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Wastewater Facility Plan - Preliminary - 1981
I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 l Inc. Village of Greenport and Town of Southold Suffolk County, New York Sect ion 201 Wastewater Facility Plan C-36-1120 Alternatives Evaluation and Environmental Assessment Report February 1981 PREUV,�,�'N,ARY ONLY 2AHolzmacher, McLendon and Murrell, P.C. Consulting Engineers. Planners and Environmental Scientists Melville, N.Y. Farmingdale. N.Y. Riverhead. N.Y. 3'F H 2M Corp. HOLZMACHER,McLENDONand MURRELL,P.C. 1 CONSULTING ENGINEERS, ENVIRONMENTAL SCIENTISTS and PLANNERS - -PCA]H LCY" FCAD Mt-IMLLE Vl1i7 i ,15169430.900 �rL_ RraD -J_', t i. X17°29060 F' LTC°FET. r-t',r.., �� ^�Y+,33-16:694-3410❑ iY.SC1.61 -3=8007 Supervisor William Pell, III and Members of the Town Board Town of Southold Town Hall, Main Road Southold, N.Y. 11971 Mayor George W. Hubbard and Members of the Board of Trustees Inc. Village of Greenport Village Hall 236 Third Street Greenport, N.Y. 11944 Gentlemen: ROBERT G. HOLZMACHER, P.E., P.P., L.S. SAMUEL C. McLENDON, P.E. NORMAN E. MURRELL, P E. HAROLD A. DOMBECK. P.E. HUGO D. FREUDENTHAL. Ph. 0 CARL E. BECKER, P.E. JOHN J. MOLLOY, P E. DONALD A. SIOSS, P.E. GARY E. LOESCH. P.E. BRIJ M. SHRIVASTAVA. P E CHARLES E, BANKS. P E. March 18, 1981 r }8,981 Re: Town of Southold Inc. Village of Greenport 201 Wastewater Facility Study Under separate cover, we have forwarded the DRAFT of the Alternatives Evaluation and Environmental Assessment Report. This report is the second part of the 201 Wastewater Facility Study. Described therein are the needs and problems of the study area. Also described are numerous alternatives and cost evalua- tions which can resolve these problems. After analysis, we have recommended various Non -Structural and Structural Alternatives for your consideration. These are: 1. Non -Structural Recommendations a. Land Use Controls b. Fertilizer Control C. Water Supply Management d. Septic Tank Management 2. Structural Recommendations a. Expansion of the Greenport Collection System b. Scavenger Waste Treatment and Disposal C. Ultimate Sludge Disposal e N HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. Supervisor William Pell, III Mayor George W. Hubbard -2- March 18, 1981 It is necessary at this time to select those alternatives you wish to implement so that the final report can be concluded. Subsequently, application can be made to proceed to implement the project, if you wish. Further USEPA regulations require that we hold a public meeting on this report before final selec- tion is made of alternatives. Accordingly, we suggest the following: 1. A joint meeting be held with the Town and Village Boards to discuss and review this report. We suggest the week of April 6, 1981. 2. At the meeting described above, the date and location for a public meeting be established. A minimum of 30 days notice is required. We tentatively suggest the week of May 18, 1981. 3. Subsequent to the public meeting, the Town and Village Boards must determine which structural alternatives they wish to implement. While there is no commitment required to construct the recommended alternative, the final report describing the "Selected Plan" is required before further USEPA funding can be provided and the 201 Study completed. In the near future, I will contact Supervisor Pell and Mayor Hubbard to set up the meetings. Very truly yours, HOLZMACHER, McLENDON & MURRELL, P.C. H. A. Dombeck, P.E. Vice President HAD:vm 1 1 1 1 1 1 1 1 1 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ALTERNATIVES EVALUATION AND ENVIRONMENTAL ASSESSMENT REPORT INC. VILLAGE OF GREENPORT AND TOWN OF SOUTHOLD TABLE OF CONTENTS 1.0 INTRODUCTION 1.1 2.0 ASSESSMENT OF FUTURE SITUATION 2.1 2.1 PLANNING PERIOD 2.1 2.2 LAND USE 2.1 2.3 DEMOGRAPHIC PROJECTIONS 2.1 2.4 SEWERING CRITERIA 2.2 2.4.1 POPULATION DENSITY 2.5 2.4.2 NITRATE CONCENTRATION IN GROUNDWATER 2.8 2.4.3 SOIL CHARACTERISTICS AND RELATIVE GROUNDWATER ELEVATION 2.14 2.4.4 SURFACE WATER QUALITY 2.15 2.4.5 AREAS TO BE SEWERED 2.18 2.4.6 AREAS OF POSSIBLE FUTURE SEWERING NEEDS 2.21 2.5 EFFLUENT LIMITATIONS 2.22 2.6 EVALUATION OF PERFORMANCE AT THE INC. VILLAGE OF GREENPORT SEWAGE TREATMENT PLANT (STP) 2.23 2.7 EXPANSION OF THE GREENPORT SERVICE AREA 2.28 2.7.1 ADDITIONAL FLOW FROM EXPANSION OF GREENPORT SANITARY SEWER COLLECTION SYSTEM 2.30 2.8 EVALUATION OF WATER SUPPLY 2.32 i 1 1 1 1 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. TABLE OF CONTENTS - CONT'D. 3.0 FUTURE ENVIRONMENT OF THE PLANNING AREA WITHOUT THE PROJECT 4.0 ALTERNATIVES 4.1 NON-STRUCTURAL SOLUTIONS 4.1.1 INTRODUCTION 4.1.2 NO ACTION 4.1.3 NON-STRUCTURAL ALTERNATIVES 4.2 STRUCTURAL SOLUTIONS 4.2.1 INTRODUCTION 4.2.2 REGIONAL TREATMENT FACILITY 4.2.3 SUB -REGIONAL TREATMENT 4.2.4 WASTEWATER TREATMENT AND REUSE 4.2.5 LAND APPLICATION 4.2.6 SURFACE WATER DISCHARGE 4.3 DESCRIPTION OF ALTERNATIVE SLUDGE TREATMENT AND DISPOSAL PROCESSES 4.3.1 INTRODUCTION 4.3.2 SLUDGE THICKENING AND DEWATERING 4.3.3 ANAEROBIC AND AEROBIC DIGESTION 4.3.4 COMPOSTING 4.3.5 LAND APPLICATION OF SLUDGE 4.3.6 SLUDGE INCINERATION 4.3.7 CO -DISPOSAL 4.3.8 SANITARY LANDFILL 4.3.9 OCEAN DUMPING 4.3.10 SCREENING OF ALTERNATIVE SLUDGE MANAGEMENT PLANS 4.3.11 SUMMARY EVALUATION 4.4 SCAVENGER WASTE 4.4.1 INTRODUCTION 4.4.2 EXISTING DISPOSAL METHODS 4.4.3 QUALITY OF SCAVENGER WASTE 4.4.4 PRESENT AND FUTURE SCAVENGER WASTE VOLUMES 4.4.5 DESIGN CONSIDERATIONS 4.4.6 TREATMENT ALTERNATIVES ii PAGE NO. 3.1 4.1 4.3 4.3 4.4 4.4 4.28 4.28 4.29 4.30 4.54 4.59 4.73 4.75 4.77 4.78 4.79 4.80 4.81 4.83 4.85 4.86 4.87 :19'I.l 4.96 4.97 4.99 4.105 4.110 4.117 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. TABLE OF CONTENTS - CONT'D. PAGE NO. 4.4.7 REGIONAL TREATMENT - COMBINED TREATMENT WITH SHELTER ISLAND 4.140 4.4.8 SCREENING OF SCAVENGER WASTE ' TREATMENT ALTERNATIVES 4.140 4.4.9 CESSPOOL AND SEPTIC TANK ' MANAGEMENT PLAN (CSTMP) 4.152 5.0 COST- EFFECTIVE ANALYSIS OF VIABLE STRUCTURAL ALTERNATIVE WASTEWATER MANAGEMENT PLANS 5.1 ' 5.1 COST-EFFECTIVE ANALYSIS 5.3 5.1.1 METHODS AND PROCEDURES 5.3 ' 5.1.2 EXPANSION OF GREENPORT COLLECTION SYSTEM - COST ANALYSIS 5.4 5.1.3 SUB -REGIONAL TREATMENT - MATTITUCK TREATMENT FACILITY - COST ANALYSIS 5.5 5.1.4 SLUDGE ULTIMATE DISPOSAL COST ANALYSIS 5.7 5.1.5 SCAVENGER WASTE TREATMENT ALTERNATIVES - ' COST ANALYSIS 5.7 6.0 CONCLUSIONS AND RECOMMENDATIONS 6.1 6.1 NON-STRUCTURAL ALTERNATIVES 6.1 ' 6.1.1 OPTIMIZATION OF THE EXISTING GREENPORT SEWAGE TREATMENT FACILITY 6.2 6.1.2 LAND USE CONTROLS 6.2 6.1.3 FERTILIZER CONTROL 6.3 t 6.1.4 WATER SUPPLY MANAGEMENT PLAN 6.4 6.1.5 SEPTIC TANK MANAGEMENT PLAN 6.5 6.1.6 ALTERNATIVE ON-SITE SEWAGE DISPOSAL METHODS 6.5 I 6.2 STRUCTURAL ALTERNATIVES 6.6 I 6.2.1 EXPANSION OF INC. VILLAGE OF GREENPORT i COLLECTION SYSTEM 6.6 I 6.2.2 SEWERING OF THE MATTITUCK AREA 6.7 ' i 6.2.3 SCAVENGER WASTE TREATMENT AND DISPOSAL 6.8 6.2.4 ULTIMATE SLUDGE DISPOSAL 6.10 i I I 1 I , i i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. LIST OF TABLES TABLE PAGE NO. TITLE NO. 2.1 1975 POPULATION AND PROJECTIONS FOR DRAINAGE BASIN SUBDIVISIONS 2.3 2.2 POPULATION DENSITY 2.7 2.3 CHARACTERISTIC COMPARISON OF SOUTHOLD VS. EAST HAMPTON (BASED ON 1975 DATA) 2.12 2.4 INC. VILLAGE OF GREENPORT - S.T.P. PERFORMANCE 2.24 2.5 CALCULATION OF ADDITIONAL FLOW FROM THE EXPANSION OF SEWER DISTRICT 2.31 2.6 GREENPORT WATER SERVICE - WATER QUALITY TEST DATA 2.34 4.1 ANNUAL NITROGEN LOADING - EXISTING AND FUTURE 4.14 4.2 OPERATIONAL CHARACTERISTICS OF VARIOUS TREATMENT PROCESSES 4.45 4.3 EVALUATION OF ALTERNATIVES 4.47 4.4 SCREENING OF ALTERNATIVE WASTEWATER TREATMENT PROCESSES 4.48 4.5 COMPARATIVE CHARACTERISTICS OF IRRIGATION, OVERLAND FLOW AND INFILTRATION/PERCOLATION SYSTEMS 4.62 4.6 SITE CHARACTERISTICS FOR LAND DISPOSAL OF WASTEWATER 4.64 4.7 ESTIMATED SLUDGE VOLUMES 4.76 4.8 ULTIMATE SLUDGE DISPOSAL ALTERNATIVES 4.89 4.9 TYPICAL SEPTAGE (SCAVENGER WASTE) CHARACTERISTICS 4.103 4.10 SCAVENGER WASTES - RAW WASTE VARIATIONS 4.104 4.11 WASTE CHARACTERISTICS AND VARIATIONS 4.104 iv 1 1 1 1 1 1 1 1 1 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. LIST OF TABLES - CONT'D. TABLE PAGE NO. TITLE NO. 4.12 SCAVENGER WASTES RECEIVED AT BAY PARK SEWAGE TREATMENT PLANT 4.104 4.13 SCAVENGER WASTE ANALYSES (mg/1) 4.106 4.14 ADDITION OF SCAVENGER WASTES TO EXISTING GREENPORT STP 4.125 4.15 PRESENT AND FUTURE SCAVENGER WASTE FLOW TOWN OF SOUTHOLD 4.141 4.16 SCREENING MATRIX FOR THE SCAVENGER WASTE TREATMENT ALTERNATIVES 4.142 5.1 PRELIMINARY COST OF EXPANDING EXISTING SEWER SERVICE AREA 5.6 5.2 COST ANALYSIS OF MATTITUCK TREATMENT ALTERNATIVES 5.8 5.3 COST ANALYSIS OF SLUDGE DISPOSAL ALTERNATIVES (BASED ON 1 DRY TON/DAY) 5.9 5.4 SCAVENGER WASTE TREATMENT ALTERNATIVES 5.11 5.5 COST COMPARISON OF RECOMMENDED SCAVENGER WASTE TREATMENT ALTERNATIVE - SOUTHOLD VS. SOUTHOLD AND SHELTER ISLAND FLOW QUANTITIES 5.12 v HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. LIST OF FIGURES FIGURE PAGE NO. TITLE NO. 2.1 PRESENT LAND USE APPENDIX "A" 2.2 FUTURE LAND USE APPENDIX "A" 2.3 SUB DRAINAGE BASINS 2.4 2.4 RESIDENTIAL AREAS EVALUATED FOR SEWERING NEEDS 2.6 2.5 NITRATE CONCENTRATIONS IN GROUNDWATER - 1974 APPENDIX "B" 2.6 NITRATE CONCENTRATIONS IN GROUNDWATER - 1975 - 1978 APPENDIX "B" ' 2.7 SOIL LIMITATIONS 2.16 2.8 SHALLOW GROUNDWATER DEPTH 2.17 m 2.9 AREAS RECOMMENDED FOR SEWERING 2.29 4.1 COMPOSTING TOILET 4.24 4.2 TYPICAL SEPTIC TANK - MOUND SYSTEM 4.27 4.3 TRICKLING FILTER FLOW SCHEMATIC - ALTERNATIVE C-1 4.35 4.4 ROTATING BIOLOGICAL DISCS FLOW SCHEMATIC - 1 ALTERNATIVE C-2 4.37 ' 4.5 EXTENDED AERATION ACTIVATED SLUDGE FLOW SCHEMATIC - ALTERNATIVE C-3 4.38 4.6 CONTACT STABILIZATION ACTIVATED SLUDGE ' FLOW SCHEMATIC - ALTERNATIVE C-4 4.40 4.7 COMPLETE MIX ACTIVATED SLUDGE FLOW SCHEMATIC - ALTERNATIVE C-5 4.42 4.8 MARSH/POND SYSTEM FLOW SCHEMATIC - ALTERNATIVE C-6 4.44 ' 4.9 LAND APPLICATION METHODS 4.61 4.10 LOCATION OF EXISTING SCAVENGER WASTE DISPOSAL SITE 4.98 vi 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. LIST OF FIGURES - CONT'D. FIGURE PAGE NO. TITLE NO. 4.11 TYPICAL CESSPOOL 4.100 4.12 TYPICAL SEPTIC TANK 4.101 4.13 SCAVENGER WASTE SURVEY 4.108 4.14 FREQUENCY OF OCCURRENCE - TOTAL BOD 4.111 4.15 FREQUENCY OF OCCURRENCE - AMMONIA NH 3-N 4.112 4.16 FREQUENCY OF OCCURRENCE - TKN 4.113 4.17 FREQUENCY OF OCCURRENCE - TOTAL SUSPENDED SOLIDS 4.114 4.18 FREQUENCY OF OCCURRENCE - TOTAL SOLIDS 4.115 4.19 FREQUENCY OF OCCURRENCE - TOTAL VOLATILE SOLIDS 4.116 4.20 FLOW SCHEMATIC - HEAD END FACILITIES - ALTERNATIVES SW -2 TO SW -10 4.122 4.21 FLOW SCHEMATIC - ALTERNATIVE SW -3 4.126 4.22 FLOW SCHEMATIC - ALTERNATIVE SW -4 4.129 4.23 FLOW SCHEMATIC - ALTERNATIVE SW -5 4.130 4.24 FLOW SCHEMATIC - ALTERNATIVE SW -6 4.133 4.25 FLOW SCHEMATIC - ALTERNATIVE SW -7 4.134 4.26 FLOW SCHEMATIC - ALTERNATIVE SW -8 4.136 4.27 FLOW SCHEMATIC - ALTERNATIVE SW -9 4.138 LIST OF REFERENCES - LITERATURE SEARCH vii R.1 1 HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. FI 11 Li 1.0 INTRODUCTION 1� 11 1 J F HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ALTERNATIVES EVALUATION ' AND ' ENVIRONMENTAL ASSESSMENT REPORT ' 1.0 INTRODUCTION This is the second volume of three concerning Wastewater Facility Planning in the Town of Southold - Inc. Village of Greenport study area. The first volume entitled, "Engineering and Environmental ' Data Report", provided a description of the existing situation and requirements prerequisite to detailed planning for waste- water facilities. This included effluent limitations and dis- charge requirements, status of existing treatment systems, popu- lation projections, zoning, land use, environmental inventory, ' along with an overview of the historical and archeological re- sources of the study area. ' This document focuses on the various alternatives that were ' considered to solve the existing and future wastewater needs in relationship to groundwater and surface water quality. Initially, ' the future situation is reviewed with data presented on future wastewater needs to minimize groundwater quality degradation. ' Proposed sewer service areas are evaluated based on popu- lation density, land use and environmentally sensitive factors which dictate present or future needs for collection of waste- water. With this information as a baseline, various alternatives are examined with regard to: expansion of the Inc. Village of HOLZMACHER, McLENDON and MURRELL, P.C. r H2M CORP. ' Greenport wastewater treatment facility; construction of re- gional/Bub-regional treatment facilities; and/or non-structural ' alternatives for non-sewered areas. Within each major alterna- tive, various treatment methodologies are evaluated. Alterna- tives examined are evaluated based on cost, both capital and ' operations, environmental assessment and implementational feasi- bility. ' Subsequent to the various meetings to be held with repre- sentatives of USEPA, NYSDEC, SCDHS, Inc. Village of Greenport, ' Town of Southold, other interested government agencies and the public, a selection from the alternatives of Volume II will ' recommend a plan of action to be adopted. This plan will be fully developed with preliminary design, cost opinions, opera- tion and maintenance costs, environmental assessment and recom- mendations for implementation in Volume III - Selected Plan Re- port. 1 ' 1.2 HOLZMACHER, McLENDON and MURRELL, P.C. i H2M CORP. 2.0 ASSESSMENT OF FUTURE SITUATION J n r 1 11 1 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 2.0 ASSESSMENT OF FUTURE SITUATION 2.1 Planning Period It is anticipated that the final selected facility plan will be placed in operation by 1985. Based on a 20 year plan- ning period, we have forecasted wastewater management needs to the year 2005. 2.2 Land Use At the present time, a master plan for future development does not exist for the Town of Southold - Inc. Village of Green- port. A review of existing and future land use, as shown on Figures 2.1 and 2.2, shown in Appendix "A", indicates that for the most part, future development will continue the existing land use mix with one exception. This exception is that vacant and small portions of farm land will be developed as low density residential areas. Expansion of commercial districts will most likely be at existing commercial developments, rather than new commercial developments. In general, the existing land use will expand into neighboring vacant land areas. 2.3 Demographic Projections The Nassau -Suffolk Regional Planning Board (NSRPB) collected present population data from the LILCO annual population survey and developed population projections through 1995 on a townwide basis. These projections were then used to determine population projections for each sub -drainage basin within the study area in 2.1 tHOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. ' 2.4 Seweri. ng Criteria within the Nassau -Suffolk sole source aquifer, the relation- ship most. commonly evaluated in determining sewering needs in an area is population density as it relates to nitrate input to ' the groundwater. Roy F. Weston, Consulting Engineers for the ' Nassau -Suffolk 208 Study, compiled nitrate data from 1962 through 1977. Based on Weston's analysis, a nitrate (NO3 N) concentration ' of 10 mg/l (drinking water standard) in the Upper Glacial aquifer occurred at densities of 8 to 10 persons per acre or more. There- fore, they concluded that at a density of 9 persons per acre (three dwelling units per acre), sewering is recommended. The ' NSRPB has adopted this criteria of 9 persons per acre as a basis ' for sewer. i.ng needs. Only three (3) relatively small developments within the ' study area would obtain a density of 9 persons per acre, as de- termined through our population projections. However, the study ' area is not typical of the Nassau -Suffolk area examined in the 2.2 ' cooperation with the NSRPB. Population projections to the year 2005 can be found in Table 2.1, with the location of each sub - drainage basin shown in Figure 2.3. A more detailed discussion of these projections appear in subsection 3.1.3 of the Engineer- ing and Environmental Data Report (Volume I). Population den- sities have been calculated using the entire land area of each sub -drainage basin. Densities for developed areas within each ' basin are evaluated in Section 2.4.1. ' 2.4 Seweri. ng Criteria within the Nassau -Suffolk sole source aquifer, the relation- ship most. commonly evaluated in determining sewering needs in an area is population density as it relates to nitrate input to ' the groundwater. Roy F. Weston, Consulting Engineers for the ' Nassau -Suffolk 208 Study, compiled nitrate data from 1962 through 1977. Based on Weston's analysis, a nitrate (NO3 N) concentration ' of 10 mg/l (drinking water standard) in the Upper Glacial aquifer occurred at densities of 8 to 10 persons per acre or more. There- fore, they concluded that at a density of 9 persons per acre (three dwelling units per acre), sewering is recommended. The ' NSRPB has adopted this criteria of 9 persons per acre as a basis ' for sewer. i.ng needs. Only three (3) relatively small developments within the ' study area would obtain a density of 9 persons per acre, as de- termined through our population projections. However, the study ' area is not typical of the Nassau -Suffolk area examined in the 2.2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 TABLE 2.1 GREENPORT - SOUTHOLD 201. STUDY ALTERNATIVES EVALUATION &ENVIRONMFNTAL ASSESSMENT REPORT SEC- TION I II III IV V VI VII VTII IX*** Village X XI XII TOTAL STUDY AR EA 1975 POPULATION AND PROJECTIONS FOR DRAINAGE BASIN SUBDIVISIONS AREA 1975 1985* 1995 2005** (ACRES) POPU. DENS. POPU. DENS. POPU. DENS. POPU. DENS. 415 400 2,995 6,460 2,01)0 400 5,695 3,005 2, 130 575 155 540 4,025 28,885 143 0.34 185 600 1.50 780 3,209 1.07 4,165 792 0.12 1,030 1,929 0.92 2,505 577 1.44 750 1,861 0.33 2,415 3,141 1.05 4,070 1,531 0.72 1,990 2,518 4.38 2,652 240 1.55 270 557 1.03 .725 1,061 0.26 1,380 18,159 1,989 22,917 0.45 302 0.73 1.95 1,333 :3.33 1.39 5,419 1..81 0.1.6 1,337 0.21 1.20 3,258 1..56 1.88 925 2.31 0.42 2,978 0.52 1.35 5,028 1.67 0.93 2,252 1.06 4.61 2,830 4.92 1.74 302 1.95 1.34 1,043 1.93 0.34 1,989 0.49 28,996 *Populat-inn was allocated based on 1975 distribution. **Population was allocated based on 1995 distribution ***Does not. include Inc. Village of. rreenport 2.3 390 0.94 1,730 4.32 7,025 2.35 1,735 0.27 4,225 2.02 1,200 3.00 3,860 0.68 6,520 2.17 2,920 1.37 2,970 5.16 390 2.52 1,350 2.50 2,575 0.64 36,890 LIMITS OF STUDY ~4. 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"r e. ►v.' � �'%'•„ � �: _ —rn.n �: i ° t . . a i . h.°t°�+,h�.i �.� � r°, �S' `'°. r IGUHL ?--3 1 y i ..••"'. z A t., R; •p'" ... it r' :.� ,M u, '� �y `,\A. ©. ,_,@- 'Goo.. i.<�ti fT o�e�• Hon _ 'rx ��< "gyp TS ",�.t ° ".. ., - �+ ti. '. �. 1`r> 'r. °y - { .':9• Yr � - t'•' ro z ,Z '� 4`� rY�l,' ."'`a, F ! /p- w / ''c''. .. � f !4' ad k%M,' •".'. .�,�, \ / - - :1 •;t€+ ./•rte 'St.• ,�'�, i ,�'� °`"^f .r'a \ I \ _ j : P { = o a r: < '3 / '>'.. e ,y •sy • �{ ` .¢ �• � ,� "�' �' i ,�� '� !•� .� � `.y• `� _ - Papa: . .r ,xaa Y :i ':."-�• r`t .>,, . lF -.,;�° ��� `� • !t •s> ,� /•••.` ttr,./ �• �� wol < c � ��. r oma`' 3 ` C P.' II 4, N• . 6 . ✓i.+' r i r,� \;t �.+°•- 4 ' CONNECTICUT STUDY NEW YORKAREASOUNO h4� ISLAND C3 ONS NEW ► JERSEY OCEAN ATLANrIc a SUB DRAINAGE BASINS TOWN OF SOUTHOLD -INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY HOLZMACHER, McLENDON & MURRELL,PC. /H2M CORP. MELVILLE.NY. CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS FARMINGDALE. N.Y. NEWTON, N.J. I I� y i ..••"'. z A t., R; •p'" ... it r' :.� ,M u, '� �y `,\A. ©. ,_,@- 'Goo.. i.<�ti fT o�e�• Hon _ 'rx ��< "gyp TS ",�.t ° ".. ., - �+ ti. '. �. 1`r> 'r. °y - { .':9• Yr � - t'•' ro z ,Z '� 4`� rY�l,' ."'`a, F ! /p- w / ''c''. .. � f !4' ad k%M,' •".'. .�,�, \ / - - :1 •;t€+ ./•rte 'St.• ,�'�, i ,�'� °`"^f .r'a \ I \ _ j : P { = o a r: < '3 / '>'.. e ,y •sy • �{ ` .¢ �• � ,� "�' �' i ,�� '� !•� .� � `.y• `� _ - Papa: . .r ,xaa Y :i ':."-�• r`t .>,, . lF -.,;�° ��� `� • !t •s> ,� /•••.` ttr,./ �• �� wol < c � ��. r oma`' 3 ` C P.' II 4, N• . 6 . ✓i.+' r i r,� \;t �.+°•- 4 ' CONNECTICUT STUDY NEW YORKAREASOUNO h4� ISLAND C3 ONS NEW ► JERSEY OCEAN ATLANrIc a SUB DRAINAGE BASINS TOWN OF SOUTHOLD -INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY HOLZMACHER, McLENDON & MURRELL,PC. /H2M CORP. MELVILLE.NY. CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS FARMINGDALE. N.Y. NEWTON, N.J. HOLZMACHER, McLFNDON and MURRELL, P.C. / H2M CORP. 208 study. It is, therefore, reasonable that environmental fac- tors in conjunction with population densities be used as the cri- teria in considering an area to be sewered. Listed below are the criteria to be examined. -- Population density -- Nitrate concentration in groundwater -- Soil characteristics -- Depth between groundwater and surface elevation -- Surface water quality Regions hAvi.ng a high demographic density and an adverse environ- mental fin} -)act will be considered in need of sewering. 2.4.1 __Population Density In order to calculate the density of developed areas within each sub -drainage basin, data were required on future land use and projected population (see subsection 2.2 and 2.3, respec- tively). Isight (8) populated regions were examined and are out- lined on Figure 2.4. For the larger regions, the total acreage of residential land use was determined. Using the projected population of each region and the assumptions listed below, den- sities of the regions were calculated and listed on Table 2.2. Assumptions: -- Land use of one or less D.U./Acre treated as 1 D.U./Acre. -- Yield factor of 1 D.U./Acre = .85 D.U./Gross Acre -- 3.0 Persons/Househol.d(1) (I) NSRPB - 208 Study 2.5 D clr.I IaF � a L O X 6 S L A A D ! O U M p -4` ,- y - Eti G . , �o 4 "now I REGION DES*MTK)N A — MATTITuCK COIII[CTtVI or 8 —LITTLE HOG NECK sTuo► mm ro�/. � AIKA C- GREAT HOG NECK ,,,,.a. p— EASF rwAR10N RESIDENTIAL AREAS EVALUATED dt,» E — sTERLING aAs N �.��� FOR SEWERING NEEDS KEY MAP F- PIPES COVE G— CONKLING PT. TOWN OF SOUTHOLD —INC. VILLAGE OF GREENPORT H— wmm owDoORT WASTEWATER FACILITIES STUDY MELVILLE, N. V. HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMINWALE. NY CONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIENTISTS NEWT EAO N v NEWTON N J 2.6 UMTS OF STUDY AREA \ �` ] 3 4 D clr.I IaF � a L O X 6 S L A A D ! O U M p -4` ,- y - Eti G . , �o 4 "now I REGION DES*MTK)N A — MATTITuCK COIII[CTtVI or 8 —LITTLE HOG NECK sTuo► mm ro�/. � AIKA C- GREAT HOG NECK ,,,,.a. p— EASF rwAR10N RESIDENTIAL AREAS EVALUATED dt,» E — sTERLING aAs N �.��� FOR SEWERING NEEDS KEY MAP F- PIPES COVE G— CONKLING PT. TOWN OF SOUTHOLD —INC. VILLAGE OF GREENPORT H— wmm owDoORT WASTEWATER FACILITIES STUDY MELVILLE, N. V. HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMINWALE. NY CONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIENTISTS NEWT EAO N v NEWTON N J 2.6 AREA* DESIGNATION A B C D TOTAL RESIDENTIAL ACREAGE 1,530 1,705 2,151 400 TABLE 2.2 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT TOTAL POPULATION (2005) 8,755 5,425 6,520 1,740 POPULATION DENSITY ACREAGE OF ACREAGE OF LAND USE LAND USE AT AT D.U. OR 2-10 D.U. LESS/ACRE /ACRE 700 830 420 1,285 569 1,582 --- 400 FUTURE POPULATION 270 150 375 510 POPULATION AT 1-D.U. OR LESS/ACRE 1,785 1,071 1,451 FUTURE POPULATION DENSITY 2.7 POPULATION AT 2-10 D.U. /ACRE 6,970 4,354 5,069 1,740 DENSITY OF AT 2-10 D.U. /ACRE 8.4 3.4 3.2 4.35 NO. OF EXISTING MAXIMUM TOTAL D.U. D.U. AREA* RESIDENTIAL (BASED ON (BASED ON DESIGNATION ACREAGE LAND USE) ZONING) E 28 80 90 F 15 40 50 G 51 120 125 H 45 160 170 -A thru D based on Land Use and Population Projections -E thru H based on Actual Field Observations *A - Mattituck B - Little Hog Neck C - Great Hog Neck D - East Marion E - Sterling Basin F - Pipes Cove G - Conkling Point H - North Greenport **Maximum Density During Summer Months FUTURE POPULATION 270 150 375 510 POPULATION AT 1-D.U. OR LESS/ACRE 1,785 1,071 1,451 FUTURE POPULATION DENSITY 2.7 POPULATION AT 2-10 D.U. /ACRE 6,970 4,354 5,069 1,740 DENSITY OF AT 2-10 D.U. /ACRE 8.4 3.4 3.2 4.35 IHOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. ' The relatively smaller developments were examined through field observations to obtain actual house counts and potential ' expansions. Again, the assumption of 3.0 persons/household was utilized to calculate the densities listed on Table 2.2. 2.4.2 Nitrate Concentration in Groundwater ' The use of on-site subsurface septic systems is considered a primary source of nitrogen pollution to the groundwater. The ' nitrate concentration found in groundwater which is to be util- ized as a potable water supply is an important parameter. The reason being that some infants (less than 1 year old) do not have a complete intestinal flora. Consequently, the bacteria which are present are capable of reducing nitrates to nitrites, but further reduction to nitrogen gas does not occur. As a ' result, nitrites are available to combine with hemoglobin to produce methemoglobin, which is incapable of carrying oxygen. ' This results in a temporary blood disorder that can be fatal, whereby t -.he. infant suffocates and may die from methemoglobi- nemia, also known as cyanosis and "blue baby disease." Methe- moglobinemia can occur at nitrate concentrations greater than 10 mg/l -N (45 mg/l -NO3). Consequently, the USEPA and New ' York State have established a maximum allowable nitrate con- centratior; in potable water of 10 mg/l -N. The natural back- ground nitrate concentration in Suffolk County .is generally ' accepted to be 1 mg/l -N. Higher concentrations are assumed to be due to man's activities. Sources of nitrates in the Town ' 2.8 ' HOLZMACHER. Mcl ENDON and MURRELL, P.C. / H2M CORP. ' of Southold are primarily agricultural fertilizer, turf ferti- lizer, and on-site subsurface sewage disposal systems and to a ' lesser extent due to leaching from sanitary landfills, indus- trial process/sanitary stormwater recharge and rainfall. ' Nitrate concentrations in the groundwater of Southold are significantly higher than most of Suffolk County groundwater, as ' shown in subsection 3.1.1.8 B of the Engineering and Environmental Data Report. An average of 59 percent of the Upper Pleistocene (Glacial) wells tested in Southold have nitrate concentrations at ' an unacceptable level, while the Suffolk County average was only 11 percent. -(1) However, it should be substantiated that the nitrogen source stems more from the extensive use of fertilizer ' on agricultural land than from the use of fertilizers applied to lawns (residential) and on-site subsurface septic systems in ' populated areas. An evaluation of previous studies which examined areas with high nitrate concentrations indicates areas where high nitrate ' plumes have developed. Figure 2.5, shown in Appendix "B", depicts these areas based on 1974 test data. By updating this map with 1975 through 1978 nitrate data, the movement or change: in the plumes could be detected. Nitrate test data for 1977 and 1978 ' were obtained from SCDHS on private wells within Southold Town- ship. SCIMS also maintains 20 observation wells within the Town- ship that are tested annually. Highlighting those wells for ' which the nitrate concentration is equal to or greater than 8 mg/l'nitrogen, new areas with high nitrate concentrations were 2.9 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. of Southold are primarily agricultural fertilizer, turf ferti- lizer, and on-site subsurface sewage disposal systems and to a lesser extent due to leaching from sanitary landfills, indus- trial process/sanitary stormwater recharge and rainfall.. Nitrate concentrations in the groundwater of Southold are significantly higher than most of Suffolk County groundwater, as shown in subsection 3.1.1.8 B of the Engineering and Environmental Data Report. An average of 59 percent of the Upper Pleistocene (Glacial) wells tested in Southold have nitrate concentrations at an unacceptable level, while the Suffolk County average was only 11 percent.(') However, it should be substantiated that the nitrogen source stems more from the extensive use of fertilizer on agricultural land than from the use of fertilizers applied to lawns (residential) and on-site subsurface septic systems in populated areas. An evaluation of previous studies which examined areas with high nitrate concentrations indicates areas where high nitrate plumes have developed• Figure 2.5, shown in Appendix "B", depicts these areas based on 1974 test data. By updating this map with 1975 through 1978 nitrate data, the movement or change in the plumes could be detected. Nitrate test data for 1977 and 1978 were obtained from SCDHS on private wells within Southold Town- ship. SCDHS also maintains 20 observation wells within the (l') Hol-macher, McLendon & Murrell, "Comprehensive Public Water Supply Study of Suffolk County, New York", 1970. 2.10 HOLZMACHER, Mct E NDON and MURRELL, P.C. J H2M CORP. 1 ' Township that are tested annually. Highlighting those wells for which the nitrate concentration is equal to or greater than 8 ' mg/1 nitrogen, new areas with high nitrate concentrations were located as shown on Figure 2.6 (see Appendix "B"). By comparing ' the areas of high nitrate concentrations on Figures 2.5 and 2.6, ' it can be seen that the nitrate plumes have increased. Based on present. land use, the center of each plume correlates to a heavy agricultural. region. However, in some areas that are not agri- culturally worked, such as Mattituck, nitrate problems are now developing. Figure 2.6 indicates that the nitrate plumes are ' expanding into the Mattituck area from the agricultural regions, in Cutrhogue (to the east), and Northville in Riverhead (to the ' west). Further evidence that supports this expansion can be found by evalul-iting the direction of groundwater flow. The direction of ' flow corresponds with the movement of nitrates to areas outside the immediate region of farm land. These outside areas correspond ' to the addition to the plumes in 1975 through 1978. In or. :ler to differentiate between various nitrogen sources, a further evaluation is necessary. By comparing the North Fork ' (Southoli9) of Long Island to the South Fork (East Hampton), we can furtliar determine the adverse impact of fertilizer practices 1 versus they use of on-site subsurface disposal systems on the ' groundwater. Table 2.3 compares the land use and population of the Townships of Southold and East Hampton. Both towns have ' similar hycirogeological characteristics and somewhat similar residential densities. In contrast, Southold has approximately 2.11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 TABLE 2.3 GREENPORT - SOUTHOLD 201 STUDY ALTF..RNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT CHARACTERISTIC COMPARISON OF SOUTHOLD*vs. EAST HAMPTON (BASED ON 1975 DATA) EAST HAMPTON 46,416 1,580 6,034 13,053 4,789 17,842 .38 persons/acre 3.0 persons/acre *Excludes the Inc. Village of Greenport Sewer District **Based on seasonal homes being occupied for 4 months/year. SOURCE: NSRPB - 208 Study, Summary Plan 2.12 SOUTHOLD Total Acreage 29,871 Agriculture Acreage 9,060 Residential Acreage 4,150 Year-round Population 14,733 Seasonal. Population** Equivalent 3,219 Total Population Equivalent 17,953 Density (Total Average) .60 persons/acre Density (Residential Acreage) 4.3 persons/acre EAST HAMPTON 46,416 1,580 6,034 13,053 4,789 17,842 .38 persons/acre 3.0 persons/acre *Excludes the Inc. Village of Greenport Sewer District **Based on seasonal homes being occupied for 4 months/year. SOURCE: NSRPB - 208 Study, Summary Plan 2.12 HOLZMACHER. Mcl ENDON and MURRELL, P.C. / H2M CORP. 9,060 acres of agriculturally worked land, while East Hampton has only 1,580 acres. Long Island Water Resources Bulletin No. ' 8 has revealed that 100 percent of the Glacial aquifer under Southold has at least moderate to high nitrate concentrations. ' East Hampton on the other hand, has only 10 percent of its ' Glacial aquifer with moderate to high nitrate concentrations, with 90 percent of the aquifer having a low nitrate concentra- tion. The one area of East Hampton that contains the moderate to high nitrate concentration correlates to the agricultural ' land use .in the Town. In addition, we have estimated the nitrogen load to the groundwater from on-site subsurface sewage disposal systems, residential lawn fertilizers and agriculturally worked areas within Southold Township. Assuming an annual average waste- water nitrogen loading of 10 pounds per person and that 50 per- cent of the loading will leach to the groundwater, we have estimated the annual nitrogen loading to be approximately 90,000 ' pounds from on-site subsurface sewage disposal systems. Based on 4,150 acres of residential land use, of which 67 percent ' apply fertilizers to their lawns, we have estimated the acreage ' of land wtiich receives turf fertilizers. A survey conducted by Cornell Cooperative Extension in the Town of Southold estimated that 52 percent of residential land use is actually turf. Using an assu1110d rate of 1.72 pounds nitrogen per 1,000 square feet and ' a leaching factor of 60 percent, we have estimated the annual nitrogen loading clue to turf fertilizers to be approximately 1 2.13 ' HOLZMACHER, MCLENDON and MURRELL, P.C. / H2M CORP. 1 66,000 pounds. We have conservatively estimated the annual nitrogen leading from agricultural fertilizers to be approxi- mately 453,000 pounds, assuming an annual average nitrogen loading of 200 pounds per agriculturally worked acre, and that 25 percent of the nitrogen will leach to the groundwater. Our estimate. .indicates that of the three major nitrogen sources, 74 percent is from fertilizers used on agriculturally worked ' areas, 11 Percent from fertilizers applied to lawns and 15 per- cent from on-site subsurface sewage disposal systems. ' Based on the above data, we conclude that nitrate pollution in the groundwater is primarily due to the fertilizer practices used on 9,060 agricultural acres of Southold Township. Although ' on-site subsurface disposal systems constitute a nitrogen input source, structural alternatives to remove the nitrogen, such as ' area -wide sewering, will have a minor effect on groundwater quality improvement. Non-structural alternatives, such as agri- cultural anis turf fertilizer management, will have a far greater ' effect i.ri reducing the nitrate input to the groundwater. 2.4.3 Soil Characteristics and Relative Groundwater Elevation The performance of subsurface leaching systems depends ' heavily on the soil conditions and depth to groundwater in the surrounding area. The Town of Southold, with the exception of ' the Inc. Village of Greenport, relies on subsurface leaching ' systems. Detailed soil maps of Southold Township taken from the "Soi.l. Survey of Suffolk County, New York" may be found in 1 2.14 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' the appendix of Volume I. Using these maps in conjunction with the soil limitations (see subsection 3.1.1.7, Table 3-9), areas with soils that hinder the performance of a leaching system can be located. Areas with poor soil characteristics are shown on Figure 2.7. The depth of soil between.the groundwater elevation and surface elevation is an important factor to consider. Using the groundwater elevation map (see Section 3.1.1.8, Figure 3.9) and the topographic map (see Section 3.1.1.4, Figure 3.4) lo- cated in Volume I of this Report, the depth of soil can be de- ' termino(l. This soil layer acts as a buffer by filtering the discharge of the subsurface leaching systems. The deeper the ' layer of soil, the better the filtration of the water. A mini- mum depth of 10 feet should be considered sufficient to filter ' the wastewater before it reaches the water table. Areas that ' do not meet the 10 foot minimum are shown on Figure 2.8. 2.4.4 _ Surface Water Qualm ' Thera is little information leading to an indication of de- grading environmental quality of surface waters within the study area. All. surface waters, both fresh and saline, seem to show ' acceptable quality. Mattituck Creek, however, could be an area of future concern because of the projected development within ' the immediate surrounding area and the lack of sufficient tidal ' flushing within the Creek. n 1 2.15 F IGURL Z. LIMITS OF STUDY AREA.a L 0 N G / S L A N D S 0 u N W 0 4 WIti j•A t dIi / .. :� 6c �. � ar � � b •. _ i.er..Yei ^.:' _ "� � w� j [!tom ✓ _ - � � _ _` O • 1. T•'• e _ .o Nk IL it O �i �~., I Q �/ �� ' � s 1 ' d G.... .•� `i ai •S•f•C f `~`Y � y � ..i `�� .�• : i�� ; to �. * \ 9 - •' •, CONNECTICUTSTUD.•� f -`M1 ••"-• _ ��� -:i '� •t NEW YORK AREA Y \ /- SOUND \ ISLAND NEW LONG JERSEY SUFFOLK NASSAU' LEGEND OCEAN INDICATES SEVERE SOL 8p AfLAN11L z000 o +� SEWAGE DISPOOSSAL FIELDS KEY MAP SOIL LIMITATIONS TOWN OF SOUTHOLD -INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE• N.Y. HOLZMACHER, McLENDON & MURRELL, P.C. I HZM CORP. FARMINGDALE. NY CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS NEWT EAD NY NEWTON N J 2.16 LIMITS OF STUDY L 0 N G ! S L A N D JERSEY SUFFOLK NASSAU' OCEAN Bo o ArLANrIC KEY MAP 2000 0 4000 FIGURE 2.8 S 0 G N D � I '�, 4� ♦1 GH I LEG ND AREAS THAT DO NOT HAVE SHALLOW GROUNDWATER DEPTH - A MINIMUM 10 FEET DEPTH OF SOIL TO GROUNDWATER TOWN OF SOUTHOLD -INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVIL HOLZMACHER, MCLENDON & MURRELL, P.C. / H2M CORP. FARMINGDALE N Y CONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIENTISTS NEWT EAD N Y EWTON. N J 1 C HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 2.4.5 Areas to be Sewered By examining each area under the criteria previously dis- cussed, the following conclusions were reached: All of the larger regions under evaluation (A, B, C, and D, as shown on Figure 2.4), although having some minor adverse environmental impact, would not develop a population density that would substantiate sewering based on 208 density criteria of 9.0 persons per acre. However, the Mattituck region - Area A has been calculated to generate a future population density of 8.4 persons per acre, just below the 9.0 persons per acre criteria. It was therefore decided that a more detailed evalua- tion of this area was warranted. Residential areas are continu- ing to develop along Mattituck Creek and Inlet. This close proximity of dwelling units and surface waters will most likely adversely impact Mattituck Creek. The lack of tidal flushing within the inner reaches of the Creek prevents a dilution affect from the Long Island Sound, thereby causing a possible buildup of nutrients within the surface waters. The Mattituck area is therefore determined to be an environmentally sensitive area, justifying future considerations. If further studies prove that the high nitrate concentrations are primarily due to the leaching of subsurface septic systems and that Mattituck Creek water quality is degrading, sewering should be reconsidered. Sewering of an area with a density of less than 9.0 per- sons per acre would have a limited impact on improving ground- water/surface water quality. Future monitoring of the groundwater 2.18 ' HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. ' and surface water quality within populated and agricultural areas should be conducted to detect trends in the nitrate con- centration or any other parameter that might indicate pollution ' affects from on-site systems. A groundwater and surface water monitoring program will be described in subsection 4.1.3. Evaluation of the small residential areas in close proximity to the existing Greenport sanitary collection system indicates four (4) specific areas, listed below, in need of sewering: E. Sterling Basin Area F. Pipes Cove Area G. Conkling Point Area ' H. North Greenport The basic criteria that classifies these areas in need of ' sanitary sewers are population density and unsuitablility of the soils for proper operation of a subsurface disposal system. ' Poor soil permeability is a common reason for septic system failures and results in public health problems. A shallow ' depth between surface elevation and the groundwater table (less ithan 10 feet) produces insufficient filtration of the wastewater prior to entering the groundwater. Deterioration of the ground- water quality results if no further steps are taken. The following briefly describes each area. Note that all ' homes presently outside the sewer service area have on-site sub- surface sewage disposal systems, such as septic tanks or cess- pools and/or tile fields. 1 2.19 1 1 1 1 1 1 1 HOIZMACHER. McIENOON and MURRELL. P.C. / H2M CORP. Sterling Basin Area The Sterling Basin Area presently consists of approximately 80 dwelling units which cover 28 acres. The area is located 2,750 feet east of the Inc. Village of Greenport sewer district. Calculation of a future population projects a density of 9.6 persons per acre. The impact on environmental quality was con- sidered as previously discussed in subsection 2.4.3. Unsuitable soil characteristics in relation to on-site wastewater disposal, combined with a high groundwater table (depth from surface eleva- tion to groundwater elevation is less than 10 feet) results in this area being unsuitable for continued dependence on subsurface septic systems. Pipes Cove Area Approximately 40 dwelling units now exist on 15 acres in the Pipes Cove Area. Most of the units are owned and operated by the Silver Sand Motel. The motel and resort cottages are considered seasonal, and are only heavily occupied during the summer months. Population density during the summer months may reach a maximum of 10 persons per acre. The dwelling units are situated 2,500 feet southwest of the existing sewer district. Adverse environmental impact results from poor soil character- istics and a shallow depth to groundwater. Therefore, this area is unsuitable for subsurface disposal systems. 2.20 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. C IConkling Point Area ' The Conkling Point Area consists of approximately 120 small homes on Kerwin Road along the shoreline, covering 51 ' acres. Calculating a future density reveals 7.4 persons per acre in this area. An environmental analysis discloses poor ' soil characteristics and shallow depth to the water table in this area. Therefore, this area is also unsuitable for sub- surface disposal systems. INorth Greenport ' Located adjacent to the northeast border of the Inc. Village of Greenport, approximately 160 dwelling units cover ' 45 acres of land. This area, known as North Greenport, will have a future population density of approximately 11.3 per- sons per acre. This density in itself justifies the need for sewering. 2.4.6 Areas of Possible Future Sewering Needs ' Inlet Point, located to the north of the Inc. Village of ' Greenport, consists of 75 acres that has the potential of heavy residential development. Presently there are 20 dwelling units ' within this area. Based on the zoning map, it is approximated that 165 dwelling units will be constructed in this area. Pro- jected density of this area is calculated to be 6.6 persons ' per acre. Soil characteristics are acceptable for subsurface disposal. Therefore, no immediate need for sewering exists. 1 2.21 1 HOLZMACHER, MCLENOON and MURRELL, P.C. / H2M CORP. However, if the land is developed at a greater density, re-evalua- tion of this area is recommended. ' As previously discussed, the Mattituck area does not indi- cate an immediate need for sewering. Future development is anticipated to increase the population density to 8.4 persons per acre, just below the sewering density criteria. Due to the environmental sensitivity of Mattituck Creek, implementation of ' a monitoring program to detect degradation of both groundwater and surface waters is required. If degradation is verified, re- evaluation of sewering this area is recommended. ' 2.5 Effluent Limitations It is anticipated that the effluent limitations to cover ' any type of ocean/sound disposal shall be as follows: 1. BOD -5 85 Percent Removal ' 30 mg/l (30 Day Avg.) 45 mg/l (7 Day Avg.) 2. Suspended Solids 85 Percent Removal 30 mg/l (30 Day Avg.) 45 mg/l (7 Day Avg.) ' These limitations are consistent with the existing dis- charge permit requirements, and are not anticipated to change. ' Effluent limitations for land application are expected to ' be governed by N.Y.S.D.E.C. groundwater standards, Class GA waters. Due to the fact that the receiving waters have been designated as a sole source aquifer, further consideration of the following effluent limitations is required: ' 1. Dissolved Solids, Total 1,000 mg/l ' 2. Nitrogen, Total (as N) 10 mg/l 2.22 IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. Based on this stringent nitrogen limitation, nitrification - denitrification processes or substantial land areas will be ' required prior to land application of effluent. 2.6 Evaluation of Performance at the Inc. Village_of ' Greenport Sewage Treatment Plant (STP) The existing Inc. Village.of Greenport Wastewater Treatment Facility is operating at approximately 50 percent of its design ' flow. Population projections of the existing sewer district in- dicates a minimal increase in flow, therefore, no need for ex- pansion of the facility is anticipated. A comparison between the treatment plant performance for the period of February 1978 to October 1980 and the SPDES ef- fluent limitation requirements are presented on Table 2.4. The comparison illustrates that for the period of record, the Green- port facility did not consistently meet the effluent limitations ' set forth in its SPDES permit. Major operational problems were encountered throughout 1978, with a distinct improvement in operational efficiency noticed after November 1978. The improve- ments in performance after November 1978 can be attributed to the following reasons: ' 1. Shelter Island Oyster Co., Inc. has discontinued the discharge of scallop processing waste and decreased the clam processing waste to a minimum. Previous operational observa- tions have detected that the plant cannot operate efficiently ' with a heavy scallop waste load. 1 2.23 1 1 1 1 1 1 1 1 1 1 1 TABLE 2.4 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT INC. VILLAGE OF GREENPORT - S.T.P. PREFORMANCE 2.24 B O D - 5 SUSPENDED SOLIDS DATE INF. EFF. % REMOVAL INF. EFF. % REMOVAL 2-78 235 33 86. 153 25 84* 3-78 142 20 86 171 39 77* 4-78 175 11 94 182 39 79* 5-78 112 18 84* 336 119* 65* 6-78 105 27 74* 152 39 74* 7-78 193 19 90 94 34 64* 8-78 169 17 90 174 35 80* 9-78 177 7 96 191 12 94 10-78 189 22 88 216 39 82* 11-78 188 21 89 163 44 73* 12-78 169 4 98 231 15 94 1-79 186 14 92 197 22 89 2-79 103 4 96 90 12 87 3-79 175 4 98 137 12 91 4-79 220 5 98 129 13 90 5-79 157 7 96 123 1.6 87 6-79 262 27 90 218 41 81* 7-79 159 5 97 151 59* 61* 8-79 133 20 85 141 22 84* 9-79 202 4 98 136 8 94 10-79 169 16 91 136 11 92 11-79 216 6 97 137 26 81* 12-79 136 10 93 128 18 86 1-80 253 9 96 340 24 93 2-80 255 13 95 217 25 88 3-80 310 10 97 153 26 83* 4-80 293 9 97 152 27 82* 5-80 237 15 94 94 39 59* 2.24 TABLE 2.4 CONT'D) GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT DATE INF. EFF. % REMOVAL INF. EFF. % REMOVAL 6-80 334 16 95 223 38 83* 7-80 168 11 93 163 24 85 8-80 266 16 94 221 36 84* 9-80 297 17 94 131 37 72* 10-80 322 20 94 309 21 93 SPDES PERMIT LIMITATIONS - BOD - 5 SUSPENDED SOLIDS 30 mg/l (7 day Avg.) 45 mg/l (30 day Avg.) 85% Removal 30 mg/l (7 day Avg.) 45 mg/l (30 day Avg.) 85% Removal *Non-compliance with SPDES Permit Limitations. 2.25 IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' 2. Robert Cooper Inc. has installed an on-site pretreat- ment process which provides for a better collection of solid ' fish process waste. Prior to this addition, the solids would be sent to the wastewater treatment plant for removal. 3• K.O.A. (Kampgrounds of America) has ceased discharging ' an acidic cleaning agent into their wastewater stream. Any one or combination of the above could have been the ' cause of the Greenport STP inability to consistently meet its SPDES permit. ' It can be seen that BOD -5 removal is not a problem of ' treatment efficiency at the Greenport Facility. However, con- sistent suspended solids removal has been difficult to maintain. ' As discussed in Volume I, Engineering and Environmental Data, the settling tank and weir loading designs at the treatment ' plant meet the Ten State Standards and therefore should be able ' to effectively remove the suspended solids. Therefore, the problem appears to be due to the aerated lagoon treatment pro- cess. Suspended solids can be a problem in systems where the detention time is greater than 10 days. Since the treatment ' plant has been operating at less than capacity, detention times on the order of 15-20 days have been occurring. It is therefore ' recommended that the STP consider upgrading to include an addi- tional process such as a sand filter or micro -strainer. Another reason for the poor settling rates can be attributed to the ' oil/grease problems that the Greenport STP has been subjected to. 1 2.26 HOLZMACHER, Mct.ENDON and MURRELL, P.C. / H2M CORP. Discussions with key treatment plant personnel indicate that the plant, since its recent upgrading, has been operating ' few items within expectations. However, two major problems were discussed which are described below: ' 1. Inability to Obtain Consistent Bacteria Kill. Over the past year, both the total and fecal coliform count of the effluent has not been consistently meeting the discharge ' limitations set by the permit. The chlorine residual analyzer was not operating correctly and in turn was sent to the manu- facturer for repairs and recalibration. After reinstallation, the coliform count did decrease, but not to an acceptable level. ' Investigation into the disinfection problem also indicated two ' other possible causes. One is the sampling location for the chlorine residual analyzer. If situated in a poor. location, ' false readings can be recorded thereby limiting this amount of chlorine being added to the effluent. The sample location must ' be located a sufficient distance from the point of chlorine addition to allow for effective mixing throughout the flow. The second cause is due to the operation of the chlorinator. ' The manufacturer recommends that the chlorinator operate with 40 psi of water pressure. However, the operator has indicated ' that when the potable water supply is being utilized for other ' purposes throughout the plant, the water pressure in the water line decreases. It is felt that the decrease in pressure is ' affecting the chlorinator. Installation of another backflow preventer prior to the chlorinator has been recommended in 2.27 0 0 n 1 HOLZMACHER. McLENDON and MURRELL, P.C. i H2M CORP. order to stabilize the pressure within the water supply feed line to the chlorinator. 2. Excessive Amounts of Oil. in Influent. Within recent months, excessive amounts of oil have been detected in the wastewater entering the treatment facility, causing operational problems throughout the plant. It was speculated that there are two sources of oil. One being a petroleum -base product seeping into the collection system and the second being a fish -base oil from a local seafood process- ing facility. The industry has been requested to eliminate their oil/grease discharge. The New York State Department of Transportation is drilling wells in the vicinity of the col- lection system to determine the source of the petroleum. It is thougl►t to be from some buried abandoned tanks on adjacent property to the sanitary sewer. 2.7 Ex)ansion of the Greenport Service Area With the Inc. Village of Greenport Wastewater Treatment Facility operating hydraulically at approximately 50 percent capacity, there is sufficient capacity for expansion of the existing sewer district. This section evaluates areas in need of sewering that are in close proximity to the existing col- lection system and could be incorporated within the sewer dis- trict. Since the Greenport STP has available capacity, it may be cost-effective to treat sewage from these areas at the Greenport STP. Areas to be considered are shown on Figure 2.9. 2.28 ' FIGURE N2 2.9 �Inlet Pt , �tirlin "" t>rrtl d ('rll,ll' ''i19 1 p \� at{Ey'E�t"n t 1 ail ° o , N,/ ".. Parker Rock /. o rj w poPO a G , �' ie�klQ%\ andy e Yunn6 , Pt �4, sewage wi.1 f, ♦1\ Disposal ' 11 tt Nei, 4 im m�, Un11ln' I �I IR t • Sell& se slut �..�� ?heater� 1 r• o L,ghts Suhslaliu" , O 17 P1 . Fanninr n �0' Pt ArshamogaulklN,/ J f Pipes . •� LANE ' ocem / Cove r , ° ° a LgGEND • ° 4t: INDiCATES AREAS o MSEWERING RECOMMENDED FOR° ° °° Wlckam yr • Conkling ot TOWN OF SOUTHOLD - INC, VILLAGE OF GREENPORT ' WASTEWATER FACILITIES STUDY MELVILLE HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMINKDALE. N Y CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL. SCIENTISTS NEWTO AD, N Y. NEWTON, N J ' 2.29 HOLZMACHER. McLENDON and MURRELL. P.C. / H2M CORP. Future population projections will increase the Village's ' flow to approximately 0.3 m.g.d. Examination of the seasonal influx of tourists during the summer months indicated only a slight increase in wastewater generation within the Greenport ' system. Peak daily flows (weekends during the summer) provided an increase of less than 16 percent over the average daily flow ' during 1980. Reserving a plant capacity of .35 m.g.d. for future population and seasonal peak flows, allows a maximum flow of 0.15 m.g.d. to be available for expanding the system while keeping ' the facility at or below capacity. In order to properly evaluate the areas under consideration, ' future population projections are required. The _projected popu- lations shown on Table 2.5 are based on existing dwelling units ' and zoning criteria established by the Town of Southold. Assuming ' an average household size of 3.0 persons per household, based on the NSRPB - 208 Study, densities were calculated and are listed I in Table 2.5. 2.7.1 Additional Flow from Expansion of Greenport Sanitary Sewer Collection System ' The expansion of the Greenport sanitary sewer collection system will increase the future total population being served by the sewage treatment plant by approximately 1,350 people. ' Recognizing that the existing service area will have an in- crease in population in the year 2005 of approximately 460 persons, a total increase of 1,810 above the existing popula- tion served can be expected. Using an average wastewater flow 1 2.30 TABLE 2.5 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT CALCULATION OF ADDITIONAL FLOW FROM THE EXPANSION'OF SEWER DISTRICT FUTURE POPULATION Sterling Basin 270 x 65 gpcpd(1) Pipes Cove (private) 150 x 65 gpcpd(2) 20 units x (Hotel) x 2 per/unit x 50 gpcpd(2) Conkling Pt. 375 x 65 gpcpd North Greenport 510 x 65 gpcpd Total Future Flow from Expansion 17,550 9,750 (3) 2,000 ( 3) 24,400 33,150 86,850 gpd Existing Population of Service Area = 3,940 Population Projection 2005 of Existing Area = 4,400 Net Increase = 500 persons Future Flow From Existing Area 4,400 x 65 gpcpd = 286,000 gpd Industry = 30,000 gpd Future Flow From Expansion Area = 86,850 gpd Total Future Flow 402,850 gpd (1) Infiltration/Inflow Analysis of Greenport Collection System; Holzmacher, McLendon & Murrell, P.C., 1974 (2) Assumed Hotel Wastewater generation at 75 percent of normal domestic usage (3) Maximum Average Daily Flow (summer months) 2.31 ' HOLZMACHER. McLENDON and MURRELL, P.C. 1 H2M CORP. per capita of 65 gpcpd(1) and 50 gpcpd for hotel residence, the increase in flow will be 116,725 g.p.d. Therefore, using ' the existing average daily flow of 0.286 m.g.d., plus the fu- ture increase of 0.117 m.g.d., the future average daily flow ' will be approximately 0.403. This is still below the plant's design capacity of 0.5 m.g.d. Therefore, no future expansion of the plant is expected. The calculation of future flows are ' on Table 2.5. 2.8 Evaluation of Water Supply ' Long Island has recently been classified by USEPA as being ' one of seven regions in the nation as having a sola (single) source of potable water. This designation places l,nng Island ' in a crucial planning situation, for if the groundwater becomes contaminated by point source and/or non -point source pollution, ' other feasible means of obtaining water would not be readily ' available or prohibitive, based on costs. The Town of Southold -Inc. Village of Greenport is in an ' even more critical position compared to the majority of Long Island. Most townships on Long Island obtain their potable ' water supply from both the Glacial and Magothy aquifers. How- ever, water present in the Magothy formation underlying Southold is too saline for domestic use. Therefore, the Glacial aquifer ' is the only source of potable water for the township. Due to ' (1) Holzmacher, McLendon & Murrell P.C. Stud I I/ Y for Inc. Village of Greenport, 1974. 2.32 IHOLZMACHER. McLENDON and MURRELL. P.C. / H2M CORP. delicate and finite nature of the fresh groundwater supply, extreme efforts will be required to preserve the quality and ' quantity of fresh water. Signs of groundwater contamination have already been de- tected throughout the Town. For example, the Inc. Village of Greenport operates water supply facilities that supply potable ' water to approximately 2,200 households. Nineteen (19) wells ' on six (6) well fields (only 12 wells in use) pumped approxi- mately 287 million gallons in 1979. However, the quality of ' this water has deteriorated in recent years. Table 2.6 shows chloride and nitrate concentrations for the years 1974-1979. ' It should be noted the each well field has had problems with ' some constituent as noted below: Well Fields No. 1 & 2 High Chlorides ' Well Field No. 3 High Manganese Well Field No. 4 High Chlorides ' Well Fields No. 5 & 6 High Nitrates Well Field No. 1 has shown excessive chlorides and bacteria ' contamination and is now used only as a power plant coolant source. ' Field No. 2 has also shown signs of excessive chlorides and has been put on reserve only to be used in an emergency situation. ' Well Fields No. 3, 4, 5 and 6 are presently being used as the potable water supply and are described below. ' PLANT N0._3 - This plant is situated on the southwest ' corner of North Road and Moore's Lane and consists of 6 driven wells 45 to 57 feet deep on a common suction and pumped by an 1 2.33 TABLE 2.6 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAI, ASSESSMENT REPORT WELL NO. 3* 4-6 4-7 4-8 5 6-1 6-2 NOTES: GREENPORT WATER SERVICE WATER QUALITY TEST DATA NITRATES 1974 1975 CHLORIDES 1977 1974 1975 1976 1977 1979 130 46 44.5 55 -- 135 170 120 165 132 99 120 55.5 85 86 33 80.5 70 185 62 50 170 47.5 49.5 38 37 52 41.5 42 38 27.5 28 27 25.5 26 NITRATES 1974 1975 1976 1977 1979 2.8 2.2 2.3 2.0 -- 8.0 7.1 4.6 7.7 7.0 6.9 6.5 8.2 7.0 7.4 1.3 3.1 3.4 3.2 4.3 12.5 7.4 12.1 11.9 11.3 12.5 10.9 10.5 10.1 10.4 6.05 5.5 7.9 7.5 9.1 (1) Well 43 in 1974 - High Manganese - .87 (2) Well 44-6 in 1975 - Iron at limit (potable water) (3) Well 43 in 1976 - High Manganese - 1.12 Recommended Not to Use Unless Necessary (4) Well 44-6 in 1977 - High Total Solids - 516 mg/l (5) Well 44-8 in 1979 - Total Iron - .60 *Wells 3-1 to 3-6 are six wells with common suction. 2.34 IHOLZMACHER. MCL.ENDON and MURRELL. P.C. / H2M CORP. ' electrically -driven reciprocating pump of 500 g.p.m. capacity. Composite chloride analyses (as Cl) at this station have varied ' widely from 40 to almost 500 mg/1. In recent years, iron and manganese content have increased to a point where this plant should only be used in an emergency. The southerly portion of this well field has been periodically flooded with pumped ex- cess surface water in an attempt to induce recharge, reduce ' salt water intrusion and limit the rise in chloride content ' which accompanies heavy pumping. There is also piping avail- of the northerly able to flood the northerly portion of the well field. The ' annual volume of recharge has varied from 0 to 90 percent of in 1965 to construct shallow wells within the Plant No. 3 pumpage since 1950. According to well log records and test borings made in connection with the sewage treatment well fields with the hope that an additional plant project in recent years, there is a thick, tough clay ' was installed, but only 15 gallons per minute, with a very poor specific capacity, was obtained. This well strata which underlies the area south and west of this well ' field, but which thins in its extension northerly. The details of the northerly termination of the clay are not known, but ' believed to be within the limits of the No. 3 well field. An attempt was made in 1965 to construct shallow wells within the pits of existing well fields with the hope that an additional ' 300 gallons per minute could be obtained from the shallow for- mation. One well was installed, but only 15 gallons per minute, with a very poor specific capacity, was obtained. This well was abondoned as a public supply well and the other contem- plated wells were not drilled. 1 2.35 11 1 HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. PLANT N0._4 - This plant is situated on a 15.4 acre parcel, 1,000 feet north of North Road and 1,700 feet west of Rocky Point Road, near the community of East Marion, and consists of three wells, each equipped with an engine -driven vertical deep well type pump. Two wells have a capacity of 200 g.p.m., but the third well's capacity has been reduced to 100 9 -p.m. There is no electric power to this well field. Neighboring irrigation wells and their extensive use during drought periods, the lack of control by any responsible agency over their use, and the dredging and construction of canals south of the main road, have imposed threats to the future re- liability of a saline free supply from these wells. Chloride data from 1957 to date indicated considerable variations in chlorides, with a general increase especially at Wells No. 4-6 and 4-8, where chlorides have fluctuated to 165 and 185 mg/l in 1977. PLANT NO. 5 - Until 1965, this plant supplied the entire needs of the North Fork division. It is situated in Southold on the east side of South Harbor Road, 1,000 feet south of Main Street (New York State Route 25) and did consist of four wells, from 44 to 60 feet in depth, only one of which is operable and equipped with a pumping unit. No auxiliary engine exists at this site. The only pumping unit (No. 5-5) that is available for normal supply has a capacity of 200 g.p.m. The duality of water from these wells is typically eastern Long Island shallow well quality, with excessive nitrates and appreciable chlorides 2.36 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 1 ' and hardness., This station has continued for years to supply the Southold area in a separate pressure zone from the rest of ' the system. This separate pressure zone was dictated by the existence of some old piping which may not withstand the higher ' pressures carried in the balance of the system. A continued gradual increase in pressure in this zone permits the entire system to be on one zone, and any weak point repaired or re- placed as discovered. PLANT NO. 6 - This plant is situated on Old North Road, ' 800 feet east of Horton Lane, in Southold. Well No. 6-1 is 90 ' feet deep, is equipped with an electric and diesel -driven deep well type pump with a capacity of 550 gallons per minute. Well ' No. 6-2 is 78 feet deep, and is equipped with an electric -driven deep well type pump. It has an approved capacity of 450 gallons ' per mintite, but at last report, the actual capacity had decreased ' to less than 200 gallons per minute due to the limited capacity of the aquifer in the immediate location of the screen. Both of these wells have been high in nitrate (as much as 11 mg/1) content for several years, but have remained in service. ' Before the nitrate levels were too high, a third well was recom- mended for this site, but not authorized or built. More recently, both wells have been discontinued from use because of the detec- ted presence of aldicarb at levels exceeding the New York State Department of Health limit of 7 ppb. ' Wells 6-1 and 6-2 have been the major supply to the water supply system, accounting for up to 61 percent of the water 2.37 u 1 11 1 1 1 1 0 u 1 HOLZMACHER. McLENDON and MURRELL. P.C. ! H2M CORP. pumped during the last few years. Together, these wells repre- sent over 50 percent of the available, acceptable quality well capacity with a combined capacity of 1.08 m.g.d. Until now, Wells 6-1 and 6-2 have also been the most reliable source of water which almost meets water quality standards. With the closure of Plant No. 6, the burden of supplying quantities of potable water rests on the remaining three plants, one of which (Plant No. 3) is so high in iron and manganese that it should only be used as a last resort. There are no sources in this entire area which are free from the threat of salt water intrusion, although Plant No. 3 is considered the most vulnerable and is rested for much of the year and Plant No. 6 is least likely to be affected by salinity. With the recent loss of Wells 6-1 and 6-2, the extreme manganese and iron in Plant No. 3 and the nitrates above the limit at Well No. 5-5, the only remaining good quality water is at Plant No. 4 whose yield is less than 500 g.p.m. Even here at Wells 4-6 and 4-8, the chlorides have increased to about two- thirds to three-quarters the limit and are suspect for future reliability. It is, therefore, conceivable that the system capacity could be reduced to one well (No. 4-7) at 200 g.p.m. The high concentration of chlorides is primarily due to the encroachment of salt water. With the groundwater table elevation approximately 1.8 feet above zero datum in the vicinity of Well Field No. 4, the fresh water -salt water interface is approximately 72 feet below zero datum. The three (3) wells on Well Field No. 4 2.38 HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. 11 ' are drilled to a depth near 80 feet with a surface elevation of 30 feet. Therefore, there is approximately 22 feet between the bottom of the wells and the salt water interface. Excessive pump - age reduces the hydraulic head around the well causing upconing of the interface. Consequently, the chloride concentration in ' the water being pumped increases. The excessive concentration of nitrates is primarily due to the use of fertilizers on agricultural land. The leachate of ' irrigation water and precipitation with soluble nitrogen, perco- lates down and contaminates the groundwater. A more detailed ' analysis has been included in Section 2.4. The high manganese concentration in Well Field No. 3 is due ' to a manganese strata leaching in the soil. Effects of manganese ' in potable water are poor taste and discoloration. With even 50 percent of the domestic water supply being ' pumped from small individual wells, similar pollution problems can be expected to an even greater extent. This is due to the ' fact that small individual wells tend to be shallow and are more tsusceptible to nitrate contamination than deep wells. With an estimated 12,000 persons obtaining potable water from shallow ' wells in the township, water treatment such as denitrification on an individual well basis is not feasible. Therefore, the 'alternative of eliminating or decreasing the pollution input to ' the groundwater seems to be the most cost-effective alternative. This alternative requires a combined water management, fertilizer 2.39 ' HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. i management and septic tank management plan. All three management ' plans are described in greater detail later in this report. ' In the early months of 1980, the chemical aldicarb was found in two of the public wells in Greenport and various private wells ' throughout Southold, at a level higher than the New York State Department of Health standard of 7 parts per billion. The source ' of aldicarb has been traced to the agricultural use of the pest- icide Temik, of which aldicarb is the major constituent. It has been proven that this chemical compound is highly toxic and does ' not decompose easily in Long Island groundwater because of the acidity of the groundwater. ' The United States Environmental Protection Agency has since taken action to prohibit the sale of Temik on Long Island, in ' order to prevent further contamination of the groundwater by 'aldicarb. Studies, such as those currently being performed by the Cooperative Extension Association, are currently being con- ducted to determine acceptable application rates for the chemi- cal and methods of removing aldicarb from the drinking water. 'This is only one chemical which has been examined in detail ' and detected. Further work in this area by the Village of Green- port, Town of Southold, local and state agencies is required to ' evaluate and monitor constituents in order to protect the ground- water. Due to the urgent need of new sources of water in the Vil- lage, the Inc. Village of Greenport is now implementing plans to construct 2 well sites within the area. Completion of both ' projects is expected in mid 1981. ' 2.40 HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. 1 ' 3.0 FUTURE ENVIRONMENT OF THE PLANNING AREA WITHOUT THE ' PROJECT 1 1 1 1 1 1 1 1 1 HOLZMACHER. McLENDON and MURRELL. P.C. / H2M CORP. 3.0 FUTURE ENVIRONMENT OF THE PLANNING AREA WITHOUT THE PROJECT The planning area may be described in terms of its boundaries and its physical characteristics. Physical characteristics and boundaries such as topography, climate, geology anti soils will not change from the conditions detailed in the "Engineering and Environmental Data" report. Environmental conditions that are considered part of the planning area description, that may be altered without the project, are discussed in the f(._)llowing sec- tions. ENVIRONMENTAL ASSESSMENT TO BE FURNISHED UNDER SEPARATE COVhR. 3.1 HOLZMACHER. McLENDON and MURRELL. P.C. / H2M CORP. 4.0 ALTERNATIVES IHOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. ' 4.0 ALTERNATIVES The preceding sections of the facility plan have presented ' qualitative data supporting the fact that the quality of the North Fork's potable water supply has been deteriorating over ' the past decade. If this trend is to continue, it is anticipated ' that the water quality will reach the point where it will become unfit for human consumption. Once the groundwater becomes "un- usable", measures would have to be taken to provide extensive treatment to purify the local polluted groundwater or to trans- ' port water from outside the immediate area to this area. Both ' options would be extremely expensive, requiring extensive con- struction of water mains to all homes throughout the study area. A more reasonable answer for overcoming the pollution problem is to prevent the groundwater from becoming further deteriorated. ' In order to prevent this continued deterioration, preventive ' actions must be implemented to reverse the groundwater pollution affects. The following sections will examine alternative means tof eliminating or reducing the sources of pollution. The land use of the Southold/Greenport Study Area dictates ' the degree of nitrogen pollution for the various sources. On-site sewage disposal systems have been determined to contribute only ' a small portion of the areawide problem. Therefore, structural alternatives, such as sewering, will only be considered on a limited basis. Populated regions were examined to determine if ' a need for sewering exists. Fertilizer from agricultural land is the major contributor of nitrogen pollution. Non-structural 1 4.1 HOLZMACHER. MCLENOON and MURRELL, P.C. / H2M CORP. ' alternatives, such as fertilizer management programs, will therefore be the basis for reducing groundwater pollution. ' Other management programs to be evaluated are: 1. Cesspool/Septic Tank Management Program. 2. Groundwater Monitoring and Management Program. ' 3. Land Use Management. One of the major reasons for conducting this facilities plan is related to the obvious source of groundwater pollution due to existing scavenger waste disposal via leaching lagoons. New York ' State Department of Environmental Conservation (NYSDEC) has man- dated the Town of Southold to discontinue the use of leaching lagoons and find an alternative disposal method that will be environmentally acceptable. As part of this wastewater facili- ties plan, we shall examine various scavenger waste treatment ' and disposal methods that are appropriate for the study area. ' The Town of Shelter Island also has been mandated by NYSDEC to find an alternate means of scavenger waste disposal instead ' of the present method of leaching lagoons. It was therefore proposed that the Town of Southold permit the Town of Shelter Island to join with them in developing and implementing an en- vironmentally acceptable treatment and disposal plan. It is anticipated that a cost savings due to economies of scale will be achieved by both Towns if Southold combines efforts with Shelter Island. A cost-effective analysis will be performed to determine ' if it would be advantageous for Southold to combine efforts with Shelter Island. ' 4.2 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. The following sections of this facilities plan will de- scribe and evaluate numerous alternatives concerned with the ' following subjects, all of which focus on the reduction or elimination of pollution to the groundwater: ' 1. Non -Structural Alternatives a. Optimization of Existing Facilities b. Land Use Controls 'C. Fertilizer Controls d. Water Supply Management Plan ' e. Septic Tank Management f. Alternative On -Site Sewage Disposal Methods ' 2. Structural Alternatives a. Expansion of Sewered Areas b. Wastewater Treatment and Reuse 'C. Land Application of Wastewater d. Sludge Disposal ' Scavenger Waste Treatment Disposal e. and ' Each alternative will be evaluated and compared to the other alternatives in terms of effectiveness in meeting effluent limi- tations, implementability, environmental assessment and cost. Finally, the most viable alternatives will be recommended for ' implementation. 4.1 Non -Structural Solutions 4.1.1 Introduction Various non-structural solutions have been studied to deter- mine if they can meet the needs of the study area. These include 4.3 iHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' No Action or status quo, optimization of the Inc. Village of Greenport STP, non-structural solutions, including land use ' controls, fertilizer controls and septic tank management, and alternative on-site sewage disposal methods. ' 4.1.2 No Action ' The No Action alternative, which is essentially a fore- cast of conditions in the planning area without the project ' was addressed in Section 3.0. ' 4.1.3 Non -Structural Alternatives The non-structural alternatives seem to be the most ap- propriate solutions to the groundwater pollution problems of ' the study area. Due to the population distribution through- out the entire area, any structural alternative to serve a large portion of the Township would be prohibitively costly. Non-structural solutions do present positive impacts on the environment. Non-structural solutions include: ' A. Optimization of Existing facilities B. Land Use Controls ' C. Fertilizer Controls D. Water Supply Management Plan ' E. Septic Tank Management F. Alternative On -Site Sewage Disposal Methods A. Optimization of Existing Facilities As discussed in Section 2.6 - Evaluation of Performance at the Inc. Village of Greenport (STP), the facility is only 1 1 4.4 HOLZMACHER. McLENDON and MURRELL. P.C. / H2M CORP. marginally meeting its SPDES effluent limitations. It is felt. ' that this can be partially attributed to the industrial fish ' waste being discharged into the collection system. In order to lessen the affect of this industrial waste and to try and ' correct inefficiencies of the plant so that consistent compli- ance with the effluent limitation can be achieved, the follow- ing modifications are recommended: ' 1. Improve communications between the Shelter Island oyster Co. and plant personnel. If pretreatment of industrial wastes is not achieved, the Village shall be contacted immedi- ately so that measures can be implemented to lessen the shock ' Load of these wastes into the plant. Measures might include discharge during peak plant flows in order to dilute the effect of industrial waste. The Village should require Shelter Island ' Oyster Co. to upgrade its oil/water separation (pretreatment) process, in order to lessen its impact on the efficiency of the Greenport sewage treatment processes. ' 2. A rapid filtration process after the final clari- fier is recommended to improve the overall efficiency of the ' plant, particularly with regard to suspended solids removal. 3. Plant personnel must continue to evaluate the ' problems associated with the high coliform count. It is recom- mended that another backflow preventer be installed prior to the chlorinator to maintain high water pressure. In addition, the current sampling point should be re-evaluated to ensure adequate mixing and detention time prior to sampling. 4.5 HOLZMACHER. McLENDON and MURRELL, P.C. ! H2M CORP. ' 4. The existing sludge disposal method of on-site landfilling will have to be discontinued in the near future. ' Planning for ultimate sludge disposal will have to be coordi- nated with the solid waste management plans to be initiated by the Town of Southold. A report prepared for the Five Eastern ' Towns recommended that the sludge quantities from the Towns would be insignificant so as not to impact the selected solid ' waste management option. Incineration, composting and the use of an acceptable -lined sanitary landfill are all potential al- ternatives for ultimate sludge disposal. B. Land Use Controls ' Land use controls can essentially prevent any major changes ' within the study area that may lead to excessive development. This alternative is presently practiced, to some degree, within ' the study area through the use of zoning. Stricter controls can be implemented to even further protect the environment. Under this alternative, legislation would be passed to help ' regulate land use in developing areas. NSRPB has projected agri- cultural acreage to decrease by some 2,000 acres. Restrictions ' should be established to control the development of this land. Town ordinances can be introduced to limit development by setting minimum lot sizes. In conjunction with this type of legislation, ' ordinances can be established that would require future high- density residential developments to provide their own sewage ' treatment capabilities. Suffolk County Department of Health Services is enforcing regulations that require the builders of 1 4.6 ' HOLZMACHER, McLENOON and MURRELL. P.C. / H2M CORP. ' large developments (expected to generate wastewater quantities of greater than 30,000 g.p.d.) to provide sufficient treatment prior to discharge. The Town should enforce this requirement and possibly consider lowering the maximum allowable flow with- out treatment, because of the sensitive nature of groundwater ' quality in the area. This type of requirement can also be initiated for development in all areas that are unsuitable for subsurface on-site systems. C. Fertilizer Controls ' In assessing the potential impact of nitrogenous ferti- lizers erti- lizers on groundwater, it is necessary to have reliable esti- mates of quantities of fertilizers applied and the subsequent ' fate of the nitrogen after application. An Island-wi.de study, performed by the Cornell University/Cooperative Extension As- sociation, as part of the 208 Study, resulted in the formula- tion of a water -nitrogen balance model which evaluates sources ' and the fate of nitrogen in the bi-county region. This report ' stated that approximately 25 percent of the nitrogen in ferti- lizers applied to agricultural farms leached to the groundwater. A total of 60 percent of the nitrogen in fertilizers applied to turf (household lawns and golf courses) leached to the ground- water. Both of these large nitrogen leaching systems can be reduced by the implementation of fertilizer controls. With approximately 30 percent (9,067 acres) of the present ' land use in Southold being agriculturally worked, a fertilizer control plan is essential. It is estimated that approximately 1 4.7 IHOLZMACHER, MtLENOON and MURRELL, P.C. / H2M CORP. ' 56 pounds of nitrogen leaches to the groundwater for every acre of agricultural land within Southold. Field studies performed ' by the Cooperative Extension Association have found that manage- ment practices can reduce this nitrogen input. ' Experimental field studies were conducted to examine dif- ferent types of fertilizer uses. Potato farms are a major con- cern since potatoes are the major crop of Southold. Results of ' the field studies indicated that equivalent yields of potatoes could be obtained with less nitrogen fertilizer than current fertilizer programs apply. The primary factor in this reduction is to supply the fertilizer when the plant requires it the most. It was found that split applications can provide fertilizer more effectively than single applications at planting, as presently practiced. Split applications decrease the total amount of fertilizer required and also decrease the amount of fertilizer potentially available for leaching. The following further describes the experimental field ' tests where a plot of land was divided with one side farmed using current management practices, the other side using ex- perimental practices. The experimental management program con- sistently used 160 lbs-N/acre. The rate applied by the current management programs ranged between 190 to 270 lbs-N/acre. The significance of this comparison is that the lower rates of ferti- lization were able to produce comparable yields.(') The premise (1) Sellwick, et al., 1977. 1 4.8 HOLZMACHER, McLENDON and MURRELL. P.C. i H2M CORP. ' of the experimental management program is that the fertilizer applications must coincide with the plant nutrient requirement. The peak of the nitrogen uptake occurs approximately six weeks after planting. Therefore, the heaviest application should ' occur at this time. The experimental fertilization program applied 60 Lbs-N/acre at planting, and followed approximately ' six weeks later with a second application of 100 lbs-N/acre. ' The current fertilizer management programs apply the bulk of the fertilizer at planting, with a light application later ' in the season. If heavy rainfall occurs in the interval, and in Southold this is more than likely, then the bulk of the fertilizer will be leached out of the root zone. Thus, in the ' experimental fertilization program, the fertilizer is made more available to the plants and less susceptible to leaching to the ' groundwater. Similar fertilizer management practice experiments were ' conducted using different types of crops common to the study area, such as cauliflower and cabbage. In order for the implementation of fertilizer controls to occur throughout the Township, farmers must be made aware of the results. Public information meetings should be arranged ' and attended by the farming sector, local officials and repre- sentatives of the Cooperative Extension Association. These new practices should be easily accepted, since they will re- duce the quantity and corresponding cost of fertilizers with no reduction in yield. 4.9 �i C C u I I r C L HOLIMACHER, McLENOON and MURRELL. P.C. / H2M CORP. Another primary source of nitrates in groundwater is that of fertilizers being applied to household lawns. Traditionally, studies of turf fertilization have been mainly directed toward achieving the highest quality of grass. Only recently has there been considerable interest in environmental degradation as a direct result of turf fertilization. Tests have shown that approximately 60 percent of the nitro- gen in fertilizers applied to a mature grass leaches to the groundwater. This will vary slightly depending upon the size of the initial application and irrigation practices. The nitro- gen 6ptake by a mature turf is relatively constant over the growing season. Therefore, the most efficient fertilizing pro- cedure would be to apply small amounts of fertilizer with fre- quent applications. Common present-day practices are to ferti- lize heavily at the beginning of the growing season and then fertilize again, but with a lighter application, late in the season. Surveys have been performed to assess the various fertili- zation rates used on Long Island. The Cooperative Extension Association conducted an extensive field survey in Southold in order to determine the characteristics of fertilizing practices. It was estimated that 67 percent of the households surveyed fertilize their lawns. The average application of those homes that fertilize was 1.72 pounds per 1,000 square feet. Other surveys have estimated the average application rate of Long Island households to be between 2.2 to 3 pounds N/1,000 square 4.10 IHOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. feet. Therefore, overfertilizing is not the case in Southold. ' The leaching problem lies in the fact that mature grass has a ' very low utilization efficiency in comparison to other crops. Turf roots are relatively shallow, therefore providing little ' contact time for a root to absorb the bulk of the nutrients (i.e. nitrogen) from the leachate. The growth of the grass ' also does not require a high rate of nitrogen at any particular ' time. Rather, it utilizes small amounts of nitrogen on a con- tinuous basis. Slow release fertilizers would help simulate ' the nitrogen requirements of the turf. Several studies have concluded that the leaching of ni- trate nitrogen is greatest when: ' a) high annual rates of nitrogen are applied; b) infrequent and heavy application of soluble t inorganic nitrogen are made; , c) irrigation or rainfall is heavy, and/or, ' d) the soil is loose, (high void ratio) and sandy. After evaluating the above conditions, it was concluded ' that nitrogen losses could be greatly reduced by irrigating at a rate commensurate with evapotranspiration, and by applying ' organic and slow release fertilizers. Mandatory use of organic, ' slow release fertilizers can be obtained through the implementa- tion of ordinances to prohibit the sale and use of other ferti- lizers within Southold and Greenport. Implementation of similar ordinances in surrounding towns or by Suffolk County would in- crease the effectiveness of this program. ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. �1 IJ u it A key factor in a nitrogen balance of household lawns is that grass is not cropped in an agricultural sense. Agricul- tural crops, once harvested, remove almost the entire amounts of nitrogen utilized by the plant. Harvesting or cutting of grass removes nitrogen only if the clippings are collected and either removed from the area or composted on-site. If the clippings are not removed and volatilization, denitrification and runoff are minimal, then virtually all the nitrogen in fertilizers supplied to mature grass will be leached. However, there is a possibility that there would be some volatilization of ammonia from the clippings. Volatilization will greatly in- crease n-crease if composting is employed. It is therefore recommended that composing of grass clippings be implemented on an indivi- dual or townwide basis to reduce nitrogen leaching due to lawn clippings. In the case of turf on sod farms, the crop is removed en- tirely at the end of the season. This will produce a large reduction of nitrogen input. The grass clippings of sod farms should also be composted. In conclusion, if the public continues to maintain an es- thetic value for their lawns, it will be impossible to com- pletely eliminate the leaching of fertilizers. However, by en- forcing the use of organic, slow release fertilizers and en- couraging composting of clippings, a large reduction of nitro- gen pollution can be obtained without affecting the esthetic value of household lawns. 4.12 ' HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. 1 Fertilizers applied to household lawns will become an even more important source of nitrogen in the future. Presently, ' there are approximately 2,200 acres of turf within the Town of Southold. Land use projections estimate that in 1995 there will be approximately 8,180 acres of turf. The increase in ' developed residential acreage emanates from existing vacant land and agricultural land converted to residential land use. ' This change will quadruple the leaching potential unless fert- ilizing characteristics practices are modified. Table 4.1 ' summarizes our estimates of nitrogen loadings due to turf ferti- lizers. Also included are the nitrogen loadings due to agri- cultural fertilizers and on-site sewage disposal systems. If ' fertilization practices do not change, a net nitrogen increase of 20 percent will leach into the groundwater over the next ten ' years. ' D. Water Supply Management Plan This section addresses the need for a water supply manage- ment plan within the study area. One of the objectives of a water supply management plan is to limit the amount of contami- nants that can enter a public water supply. Since the entire ' water supply for the study area is derived from groundwater (specifically the Glacial aquifer), it is important that the ' contaminant input into the aquifer be limited. The only major water supply system in the study area is owned and operated by ' the Inc. Village of Greenport. Presently, this supplier utilizes a water supply management plan that includes monitoring the 1 4.13 LANDUSE Existing 1975) Household Lawns Agricultural On -Site Septic Systems TABTE 4.1 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT ANNUAL NITROGEN LOADING EXISTING AND FUTURE UTILIZED INITIAL LEACHING ACREAGE LOADING(lbs) LOADING (lbs) 2,204 9,060 17,953 persons* 110,640 1,811,460 179,530 66,380 452,870 89,770 % OF TOTAL LEACHING 10.9 74.4 14.7 .P. TOTAL 2,101,630 609,020 100.0 Future (1995 Household 8,176 AC 410,420 246,250 33.7 Lawns Agricultural 7,200 AC 1,440,000 360,000 49.2 On -Site 25,000 persons* 249,720 124,860 17.1 Septic Systems TOTAL 2,100,140 731,110 100.0 *Population Equivalents 11 u 1 C 11 C 11 1 1 HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. quality of existing wells within the district. The objective of the present plan is to correct problems after they have occurred. This plan should be expanded to include measures that, if imple- mented, would prevent problems from occurring. The following subsections describe various procedures, some of which are applicable to the entire Township, while others are only applicable to the Inc. Village of Greenport water supply system: (1) Groundwater/Surface Water Monitorin2Program The purpose of a monitoring program is to detect changes in the quality of groundwater and surface water within the study area. By monitoring various constituents, further deterioration can be prevented by implementing various management programs. The major objectives of such a program within the Greenport - Southold area would be: a. Detect changes in the nitrate concentration in the groundwater throughout the study area, stressing the agricultural and densely popu- lated residential areas. b. Detect changes in the ammonia, nitrate and coliform concentrations in surface waters. C. Detect changes in the chloride concentration in the groundwater in those areas where ex- tensive pumping occurs. The locations, depths and number of sampling points are critical to obtaining meaningful data. Suffolk County 4.15 IHOLZMACHER. McLENDON and MURRELL. P.C. / H2M CORP. Department of Health Services (SCDHS) and the United States Geo- logical Survey (USGS) maintain numerous observation wells through- out Suffolk County. Utilizing these wells, the number of new wells can be reduced significantly. There may also be existing ' private wells which are inactive and therefore could the used for ' monitoring. Active wells should be avoided, since normal pump- ing creates a hydraulic cone around the well. This cone yields ' water from a strata that is larger in vertical depth than what one would obtain by sampling the strata with little or no pump- ing. Consequently, sampling from active pumping wells may re- sult in the collection of erroneous data. Two major advantages ' of using observation wells for monitoring are samples collected ' are from a selected vertical section of the aquifer and second, if the casing diameter is small, wells can be installed inexpen- sively and rapidly. The major disadvantage in using observation wells is that improper construction can contribute to vertical ' migration of contamination. ' Well clusters should be utilized in areas where the chlo- ride concentration is to be monitored. Advantages of using the ' cluster method include, 1) excellent vertical sampling made pos- sible when sufficient number of wells are constructed, 2) "tried and true" methodology, accepted and used in most contamination ' studies where vertical sampling is required, 3) relatively simple installation, and 4) low cost if only a few wells per cluster are ' required and if the drilling contractor has equipment suitable for installation of small diameter wells. However, the well 1 4.16 IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. cluster method is not problem -free. Disadvantages include, ]) ' large vertical sections of the aquifer unsampled if only a few ' wells are installed, 2) small diameter wells can be used only for monitoring and cannot be used in abatement schemes, and 3) ' in small diameter wells, sample collection is tedious and dif- ficult if the water level is below suction lift. ' As part of the selected plan report, a map will be ' prepared showing the location of monitoring wells. In addition, the analyses to be performed will be discussed in greater detail. In order for this program to be successful, an efficient record-keeping system is essential. Basic well information and ' test data would be arranged in such a manner that regional and ' local trends in water quality can easily be evaluated. Such a system will allow for the necessary controls to be implemented ' upon observation of deteriorating water quality. (2) Irrigation Wells Presently, irrigation utilizes approximately 60 per- cent of all groundwater pumpage from the Town of Southold. No control or constraints are put on irrigation practices of the ' farmers. Because of this extremely large quantity of water being withdrawn from the ground, certain restrictions should ' be developed to maintain the elevation of the water table. Even though the water is applied immediately to the land, only a small percentage is recharged back into the aquifer; the rest ' is lost through evapotranspiration. Serious groundwater de- pletion could occur if no constraints are put on irrigation ' practices, particularly during drought periods. 1 4.17 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. ' Continuous pumping with no precipitation recharge would lower the water table and increase the probability of salt water intrusion along the coastline. Irrigating during the night is one practice that will lessen the quantity of ' water lost through evapotranspiration, thereby reducing the quantity of water that has to be pumped. Moisture indicating devices that automatically start irrigation systems when the moisture within the soil drops below a predetermined level should be investigated. If imple- mented, this practice would result in irrigation only when the soil has an insufficient amount of moisture. ' (3) Controlled Pumping ' The problem of excessive chlorides, due to salt water intrusion, is directly associated with excessive pumping within ' a small area. Controlled distribution of pumpage over a larger area (i.e., all the well fields together) with the monitoring ' of the chloride concentration at each well can help prevent further salt water intrusion. (4) Increase Recharge ' The high chloride concentration problem in the public wells of Greenport is primarily due to salt water intrusion, as ' a result of excessive pumping. We believe that by increasing the recharge to the groundwater, we can reduce salt water in- trusion. Presently, subsurface disposal systems, storm water ' recharge basins and natural precipitation infiltration generate the volume of recharge into the aquifer. The recharge of 1 4.18 IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. wastewater effluent in the appropriate areas can form a barrier between the salt water and fresh water bodies. The environ- mental assessment of the alternative of recharging the Green- port Sewage Treatment Plant effluent will be examined in Sec- tion 4.2.7. (5) conservation of Water ' Water conservation is a means of reducing the total ' water pumpage being withdrawn from the aquifer. It also re- duces the total volume of wastewater being discharged back ' into the water table through leaching. Flow reduction can be achieved by simple modifications to water -use appliances and ' plumbing fixtures. With less wastewater to treat and dispose ' of, the life of on-site disposal systems would also increase. Nearly 70 percent of the total household water usage ' is generated from toilets, laundry and bath. Using low -flow toilets, "sudsaver" washing machiiies, restricted flow shower ' heads and recycling bath and laundry wastewater for toilet ' flushing are four commonly mentioned ways to save water. By reducing the toilet flushing volume to 3 gallons, clothes wash- ing to 28 gallons using a sudsaver, and bath and shower volume to 15 gallons, average water usage could be reduced by approxi- mately 17 percent.") Recycling bath and laundry wastewater ' to flush toilets requires more complex modifications, but could increase the savings to 33 percent. (1) Witt, M.D., Water Use in Rural Homes, Small Scale Waste Management Project, University of Wisconsin, 1974. 1 4.19 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' Concerted public information programs, in conjunction with requiring future housing developments to install the afore- mentioned devices, will help conserve water and preserve the ' water supply. E. Septic Tank Management ' Septic tank management is essentially the only viable non- structural method of dealing with problems with existing septic systems in the area. Although septic tank management methods ' are capable of removing septic sludges, predicting failures and preventing overflows by removing septage, they cannot increase ' the nature of percolation rates of the soil. This is, of course, the major cause of septic system failure in the study area. In ' addition, septage removed from failed systems would have to be treated and disposed of by some other method. Presently, septic wastes are disposed of to open leaching beds at the Southold ' landfill. The provisions made for disposal will be discussed in greater detail in Section 4.4 - Scavenger Waste. Septic sys- tem failures may create health hazards, become public nuisances and adversely impact ground and surface waters. F. Alternative On Site Sewage Disposal Methods ' Traditionally, sewers have been recommended to alleviate current problems with on-site sewage disposal systems. Alter- nate technology will be investigated to determine if other on- site disposal methods are available to cost-effectively treat the wastewater without adverse environmental impact. 1 4.20 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' These systems could be implemented throughout the study area to supplement or complement a septic tank management 1)1.an ' as non-sewering solutions to the wastewater needs of the area. Cesspools, septic tanks and leaching fields are a source ' of groundwater, contamination within the study area. In on-site disposal systems, bacterial action digests the solid material and the liquid effluent then leaches to the groundwater. In ' theory, filtration by earth material provides additional treat- ment so that the liquid, when it arrives at the groundwater table, has a relatively low solids concentration. However, ' many constituents carried by the effluent are introduced to the groundwater. Those which present the greatest threat to ' groundwater quality are, excessive concentrations of nitrogen, organic chemicals, detergents, metals, and to a lesser extent, viruses. This section will, therefore, examine alternative ' on-site disposal methods that might minimize the leaching of these constituents to the groundwater. ' The following summary of alternative systems is not in- tended to be an exhaustive list of every available device or process. Rather, this review classifies into general cate- gories systems which may be considered as alternatives to con- ventional collection and treatment facilities. ' 1. Toilet Facilities (a) Pit Privies - A pit privy consists of a hand -dug or ' bored pit over which a shelter is placed for privacy. Problems frequently encountered with these units included groundwater and 1 4.21 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 1 ' surface water contamination, health hazards resulting from vec- tor-borne disease transmission, and odors. Implementation and ' acceptance by the public is extremely unlikely. (b) Drum and Vault Privies - The primary reasons for the ' use of these units are that they can be used in areas of high ' water tables with no groundwater contamination and can be sub- stituted for septic tank leach field systems in areas of poor ' soil permeability. Wastes are collected above ground either in a 55 -gallon drum or in a cement vault. The accumulated wastes must be removed periodically. (c) Chemical Toilets - These devices use biodegradable ' chemicals to inhibit bacterial buildup and control odor. Wastes ' are collected in a storage container and removed periodically. Chemical toilets are currently used mainly for temporary sani- tation facilities at construction sites and athletic events, in recreational vehicles, parks and recreational areas. ' (d) Incinerating Toilets - These units are self-contained ' gas or electrically operated systems which evaporate all liquids, reduce solids and eliminate bacteria by burning. The residual ash must be removed periodically. Few incinerating units are presently in use due to high capital and operating costs. (e) Waterless Composting Toilets - Originally developed ' in Sweden, the composting toilet (or clivus multrum) is similar in operation to the backyard "privy". Both toilet and solid organic kitchen wastes are discharged to and then composted in a specially designed bin. Shower and sink wastewater is disposed 4.22 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' of by different mechanisms, such as a cesspool or septic tank system. A typical composting toilet is depicted in Figure 4.1. The system uses the heat of aerobic composting to destroy ' pathogenic organisms, decompose organic wastes and drive off the water content of the wastes. After one to two years of storage ' in the composting chamber, the organic waste is converted into a dried compost material which, if properly treated, is ready for ' garden use or other disposal. Gasses and other volatile material ' that are produced are vented through a stack. Since the clivus multrum type of system does not use water, it results in a sig- nificant water savings (as much as 40 percent in a typical house- hold). This disposal method would be effective when construct- ing new residential facilities, however, major modifications ' would be required for installation in existing facilities. 2. Graywater Blackwater Separation ' Although the need for a water -carriage system for disposal of fecal wastes (blackwater) can be solved by substituting one iof the waterless varieties discussed above, there remaims the problem of disposing of the wastewater from the kitchen, baths ' and laundry (graywater). At present, the only acceptable dis- posal methods for graywater are through sewers or septic tank/ leach field systems. There are several proprietary devices and plumbing modifications an the market which provide for graywater reclamation for use in the house or yard. 1 CIS 1 4.23 VENTILATION STACK TOILET UNIT TOILET WASTES REFERENCE: ON-SITE DISPOSAL SYSTEMS; USEPA- NATIONAL CONFERENCEy MARCH 1977 FI(;1 IRF d 1 m GARBAGE DISPOSAL UNIT FLOOR ABOVE MULTRUM COMPOSTING UNIT i/ KITCHEN ACCESS PORT WASTES II BAFFLE I I AIR MST HUMUS STORAGE `� CHAMBER COMPOSTING TONT (CLIVUS M(JLTRUM ) TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE, N.Y. HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMINGDALE.NY CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS NEWTEWT EAD. N Y NON. N J 4.24 i HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 3. Treatment and Disposal Systems (a) Home Aerobic Treatment Units - Individual home aerobic ' treatment units have been used in a few states, most notably in Colorado, as an alternative to septic tanks. These units bubble air through the incoming sewage and function in a manner similar ' to a small extended aeration activated sludge plant. Waste treatment, utilizing aerobic microorganisms, is ' more biologically efficient because the free oxygen dissolved in the wastewater allows the organisms to rapidly feed on and de- grade both the suspended and dissolved organic matter. The aerobic home treatment, however, does not remove nitrates from ' the wastewater. Reportedly, results have been disappointing due ' primarily to homeowner neglect of maintenance and insufficient design allowance for surge flows. ' (b) Evapotranspiration (ET) Systems - ET systems provide a means of wastewater disposal in some areas where site conditions are not favorable for leach field soil absorption. Evaporation 1 of moisture from the soil surface and by plant transpiration pro- vides the disposal mechanism. This system can be used in areas ' where the annual evaporation rate exceeds the annual precipitation rate by a significant amount, so that the wastewater applied to ' the ET bed can be disposed of without danger of surface or ground- water contamination. ET systems can also be designed to supple- ment absorption in slowly permeable soils. ' Utilization of the ET system on Long Island, specifically in Southold, is not feasible because the annual precipitation ' rate exceeds the annual evaporation rate. 1 4.25 IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. (c) Mound Systems - Mound systems take advantage of the soils' ability to absorb and purify wastewater. Basically, ' the method consists of artificially raising the leaching field (absorption field) above the natural soil by building the seep- age system in a mound of medium sand. Figure 4.2 depicts a typical system. The household waste enters a conventional septic tank. After treatment, the effluent is pumped to the ' percolation system located in the mound. This consists of a drain tile constructed with perforated pipe in an envelope of sand fill. In this system, the wastewater is uniformly dis- tributed over the absorption field. The mound system is cur- rently being researched and evaluated to determine the exact ' design parameters. This method is not cost-effective for in- dividual households, since it requires a pump, pump housing structure, controls and alarms, and connecting conduits, in ' addition to the septic tank and percolation system. There are operation and maintenance costs involved with this system that ' are also excessive. This method can be utilized in areas where the depth to groundwater is shallow, such as near the shoreline where septic systems are unable to percolate efficiently. ' 4. Modification of Existing Septic Tank Systems Recently, SCDHS has conducted studies which investigated ' methods to remove nitrogen from wastewater in subsurface dis- posal systems. Results have shown that nitrogen leaching to the groundwater can be reduced, but only through major modi- ' fications of the septic tank system. Modifications including 1 4.26 FI(,I IRF d 9 Tulesail Subsoil \',� Pet tot I)Ipe Clay till of topsoil Fiom � 1 house W.itel smid till t TopSoiI levelMAI LESS THAN Stolle III Plowed sm face 10' ScumHuth wutei.*" dial 1-1111 switch WATER Pump Pump switch SEPTIC TANK PUMPING CHAMBER \ 1'fi- to ? inch PVC pipe hom pumijiny chamber 1 inch perforated PVC pipe �II le� - GII SNI '!I ilii - �I' VIII' Seepage tlench 5/8 to T inch stone TYPICAL SEPTIC TANK- MOUND SYSTEM REFERENCE: ALTERNATIVES FOR SMALL WASTEWATER TREATMENT SYSTEMS ON-SITE DISPOSAL/SEPTAGE TREATMENT AND DISPOSAL USEPA TECHNOLOGY TRANSFER 1977 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE. N. V. HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMINGOALE.NY CONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIENTISTS NEWTON. A IN N Y NEWTOJ 4.27 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. the addition of a wastewater pump, methanol feed equipment, ' electrical controls and miscellaneous supplies will greatly in- crease the cost of waste disposal. This method would be more easily implemented on new residential developments, rather than ' trying to modify existing septic tank systems. In either case, major problems with this alternative are high operating costs (methanol) and frequent attention by the homeowner is required. ' SCDHS is presently investigating alternate carbon sources in hope of reducing O & M costs. 4.2 Structural Solutions 4.2.1 Introduction Historically, regional collection treatment and disposal ' of wastewater has only been implemented in densely populated regions such as cities and villages, in response to public health ' concerns. Rural areas depended strictly on individual on-site ' subsurface systems. However, rural developments are being con- sidered for regional sewage collection and treatment systems ' due to both public health and environmental concerns. With individual septic systems in Southold discharging into the groundwater'without providing an adequate degree of water ' purification, the quality of the local drinking water has been deteriorating. The following sections will evaluate various ' sewering alternatives by examining the effectiveness of the treatment processes to meet effluent limitations, associated ' capital and operating costs in maintaining these systems and I an environmental assessment of implementing these alternatives. 1 4.28 iHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' 4.2.2 Regional Treatment Facile The alternative of a regional treatment system would pro- vide for a wastewater transportation system consisting of a ' sewage treatment facility capable of serving the entire popu- lation of the Town of Southold. This would eliminate existing ' and future discharges from all sub -surface septic systems throughout the study area. An extensive collection system ' would be required to transport the sewage from the entire ' Township of 45 square miles to the treatment facility. The existing Inc. Village of Greenport Sewage Treatment Plant could be upgraded and enlarged as required, or a new regional facility could be constructed. Effluent discharge would be to Long Is- land Sound via an outfall at either the existing outfall site or to Gardiners Bay, or disposed of on land. Immediate con- siderations were given to transporting the wastewater generated throughout the study area. With slightly greater than 20,000 persons occupying over 45 square miles of land, preliminary in- vestigations indicate that the collection system required to ' connect all of the dwelling units to the treatment facility is of such magnitude that the cost for transporting the wastewater ' alone is prohibitive. Furthermore, this alternative does not take into account the need for sewering. Regional treatment results in the en- tire population being sewered, regardless of need, and is therefore not recommended. 4.29 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' 4.2.3 Sub -Regional Treatment This management alternative would provide wastewater treat- ment on a sub -regional basis as indicated below: ' 1. Expand and upgrade the existing Inc. Village of Greenport facility in order to serve the surround- ing areas. ' 2. Construct a treatment facility within the western section of the Township (i.e. Mattituck) to serve the surrounding areas. Once again, the transportation cost of conveying the waste- water from all dwelling units to a treatment facility is too significant for a town of this size. Therefore, it is bene- ficial to evaluate distinct areas in order to determine the needs for sewering. Then, only the areas in need will be ' sewered. ' As discussed in Section 2.4 - Sewering Criteria, only a few areas have shown an obvious need for sewering. These areas ' surround the Inc. Village of Greenport and will not need to be evaluated in the treatment alternatives section since sufficient ' treatment capacity is available at the existing Greenport STP. Sewering/treatment needs are not as critical in the Matti - tuck area. As previously discussed, if the recommended ground- water monitoring program for the Mattituck area indicates a need for sewering, a sub -regional treatment alternative will have to ' be implemented. The following subsection evaluates alternative treatment schemes that can be utilized in the Mattituck area, if required by the monitoring program: 1 4.30 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. ' A. Evaluation of the Mattituck Area The groundwater beneath the Mattituck area is high in ni- trates, and in some places, exceeds the drinking water standard of 10 mg/1 -N. We have recommended that a monitoring program ' be implemented in this area. If the results of this program ' indicate the source of nitrate contamination tobe on-site subsurface sewage disposal systems, then a cost - effective method of collecting and treating the wastewater from this area is needed. The intent of this section is to determine the most cost- effective method based on an evaluation of the following alter- natives: The first, Alternative A, is to take no structural ' action. The community will continue to use subsurface disposal systems. Alternative B is to collect and then pump the waste- water to the existing Inc. Village of Greenport STP. This plant is presently operating .25 mgd below design capacity. Since ' the additional flow from Mattituck would be .46 mgd, expansion of this plant would be required. Alternative C would be to construct a treatment plant in the Mattituck area to treat a ' minimum of .46 mgd. If the monitoring program indicates contam- ination, then Alternative A is not an environmentally sound plan ' and is, therefore, not recommended. To determine which Alterna- tive, B or C, is the most cost-effective, total costs of each must be calculated and analyzed. The following section will ' evaluate various treatment systems and select the most cost- effective for treating .50 mgd at Mattituck. This cost will 1 4.31 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' then be compared to the total cost of pumping the Mattituck flow to Greenport and upgrading the existing Greenport Sewage Treat- ment Plant. The following treatment processes are to be considered as a possible system to treat wastewater from the Mattituck area: ALTERNATIVE DESCRIPTION C-1 Trickling filter with primary sedi- mentation C-2 Rotating biological discs C-3 Extended aeration activated sludge ' C-4 Contact stabilization activated sludge C-5 Complete mix activated sludge ' C-6 Marsh/Pond system Each of the above alternatives will be evaluated under two ' (2) options, except Alternative C-6. Option "a" requires that the effluent be discharged into Long Island Sound by an outfall. 1 In Option "b", land application will be utilized to treat and ' dispose of the effluent. The limiting factor used to select the treatment system is ' that it must be,able to achieve the expected effluent discharge criteria listed below: Minimum Percent Removal of BOD -5 = 85 Percent Maximum BOD -5 Concentration = 30 mg/1 (30 Day Avg.) Minimum Percent Removal of SS = 85 Percent Maximum SS Concentration = 30 mg/1 ' (30 Day Avg.) 1 4.32 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. In addition to these effluent standards, a nitrogen limi- tation of 10 mg/1-N will also be required for all alternatives ' under Option "b" - Land Application. Therefore, Option "b" re- quires nitrification/denitrification prior to discharge or sub- stantial land area to allow for low nitrogen loadings to the ' groundwater. If an alternative cannot achieve these performance standards, ' it will be eliminated from further evaluation. Description of Alternative Wastewater Treatment Processes 11 7 C 1. Alternative B Pumping to Greenport Sewage Treatment Plant - As previously discussed, the Inc. Village of Greenport Sewage Treatment Plant has sufficient excess treatment capacity for both the future population and future expansion within the immediate vicinity of the sewered area. We have therefore examined the alternative of transporting sewage from Mattituck to Greenport in order to utilize available excess capacity. Preliminary examination of this alternative indicates that the distance between the collection point in Mattituck and the Greenport site is over 13 miles (70,000 feet). Due to the topography between the two sites, it was determined that two (2) pump stations will be required to transport the wastewater to Greenport. 2. Alternative C -la This alternative entails the use of a single stage trick- ling filter preceded by primary sedimentation. Primary effluent 4.33 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. is sprayed on a bed of crushed rocks or other media coated with ' biological film. As the wastewater flows over the biological ' film, the soluble organics are rapidly metabolized and the col- loidal organics absorbed into the surface. Sludge is produced ' when the biological film is sloughed from the media. Clarifiers remove the solids through sedimentation. The sludge is then de - watered using sludge drying beds. Effluent from this system will ' be discharged to the Long Island Sound or Peconic Bay through an outfall pipe. The flow schematic is shown on Figure 4.3. ' 3. Alternative C -lb This alternative is identical with Alternative C -la, ex- cept that the effluent will be discharged using land application. Sufficient nitrogen removal will be required prior to land appli- cation in order to minimize the nitrogen loading to the ground- water. Since the lower portion of a deep trickling filter fre- quently supports populations of nitrifying bacteria, only a ' denitrification process will be needed. 4. Alternative C -2a The second alternative uses rotating biological discs, 1 consisting of a.series of large diameter plastic discs mounted vertically on a shaft and installed in a cylindrical tank. The ' discs are partially submerged and are slowly rotated through ' the mixed liquor. When rotated, air enters the voids while the liquid trickles out over the fixed film of biological growth ' attached to the disc. Sludge is produced when the biological growth film becomes too thick and sloughs from the disc into 1 4.34 �r r r r r r r r r rr r rr r� rr it rr lr rr w Ln % A LANDFILL GRAVITY THICKEN " DEWATERING 8 COMPOSTING C INCINERATION TE DISPOSAL FILTRATE AND SUPERNATANT LEGEND WASTEWATER TRICKLING FILTER moseloselovs SLUDGE FLOW SCHEMATIC ALTERNATIVE C— i TOWN OF SO UTHOL D - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELvaLE. N Y HOLZMACHER, MCLENDON & MURRELL, P.C. / H2M CORP. CONSULTING ENGINEERS PLANNERS and ENVIRON".lENTAL SCIENTISTS RECIRCULATION PRELIMINARY TREATMENT (SCREENING) AND GRIT REMOVAL) RAW PRIMARY TRICKLI FINAL EFFLUENT SETTLING FILTER TO OUTFALL WASTEWATER TANK UNIT LARIFIER OR LAND FROM DISINFECTION APPLICATION COLLECTION SYSTEM % A LANDFILL GRAVITY THICKEN " DEWATERING 8 COMPOSTING C INCINERATION TE DISPOSAL FILTRATE AND SUPERNATANT LEGEND WASTEWATER TRICKLING FILTER moseloselovs SLUDGE FLOW SCHEMATIC ALTERNATIVE C— i TOWN OF SO UTHOL D - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELvaLE. N Y HOLZMACHER, MCLENDON & MURRELL, P.C. / H2M CORP. CONSULTING ENGINEERS PLANNERS and ENVIRON".lENTAL SCIENTISTS IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 1 ' the tank. A final clarifier removes the solids by sedimenta- tion. Sludge will be thickened, digested and then dewatered ' on drying beds and the final effluent discharged to the Sound or Bay by an outfall. The flow schematic is located on Figure 4.4. ' 5. Alternative C -2b This alternative is similar to Alternative C -2a, except ' that the effluent will be discharged utilizing land application. Land application will require a higher degree of nitrogen re- moval than surface water discharge. By installing additional ' biodiscs, nitrification can be achieved. Furthermore, a de- nitrification process will be required. 6. Alternative C -3a 1 4.36 Under this alternative, an extended aeration activated ' treat the wastewater. This sludge plant would process operates ' in the endogenous respiration phase of the growth cycle, which necessitates a relatively low organic loading and long aeration ' time. The aeration time is approximately 24 hours compared to 6 to 8 hours for a conventional activated sludge system. The extended aeration system excludes the primary sedimentation ' phase. Following screening and degritting, raw wastewater is aerated and sent to the final clarifier. Sludge will be de ' watered on drying beds while the effluent is pumped to Long Island Sound or Peconic Bay. The flow schematic is shown on ' Figure 4.5. 1 4.36 m m m m m m m m m m r m m m m m m m r PRIMARY SEDIMENTAT TANK RAW WASTEWATER FROM COLLECTION u SYSTEM SCREENING AND GRIT REMOVAL LEGEND --- WASTEWATER J•51"•""" SLUDGE RECIRCULATION FINAL CLARIFII Qln _ mere DISINFECTION EFFLUENT TO OUTFALL OR LAND APPLICATION A LANDFILL COMPOSTING JCINERATION UL I IMA It SLUDGE DISPOSAL ROTATING BIOLOGICAL DISCS FLOW SCHEMATIC ALTERNATIVE C -2 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE, N Y HOLZMACHER, McLENDON & MURRELL, P.C. / 1-12M CORP. FAAMPX-DALE CO"JSULTING ENGINEERS PLANNERS and ENVIRONMENTAL SCIENTISTS NE'r,—eA l' 16 4a w cc RAW WASTEWATER FROM COLLECTION SYSTEM SREENING AND GRIT REMOVAL AIR LEGEND ----- WASTEWATER illi,m•e•stol SLUDGE EXTENDED EFFLUENT AERATION JCLARIFIER 00 TO TANK OUTFALL DISINFECTION OR LAND APPLICATION GRAVITY THICKENE Fill A LANDFILL ANAEROBIC DEWATERING COMPOSTING DIGESTERINCINERATION ULTIMATE SLUDGE EXTENDED AERATION ACTIVATED SLUDGE DISPOSAL FLOW SCHEMATIC ALTERNATIVE C-3 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE. N Y HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FAPIPN+GOA:F 1. - GO'JSULTING ENGINEERS PLANNERS and ENVIRONMENTAL SCIENTISTS c� c m A 4A IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' 7. Alternative C -3b This alternative is identical with Alternative C -3a, ex- cept that land application will be utilized in lieu of surface water discharge. Both nitrification and denitrification pro- cesses will be required to remove sufficient nitrogen. 8. Alternative C -4a This alternative utilizes contact stabilization, which ' is a modification of the conventional activated sludge process. The return activated sludge is reaerated before being mixed with ' the primary effluent. This reaeration permits a smaller aeration tank to be used. Effluent from the secondary clarifier would be pumped to the Sound or Bay through an outfall. Sludge would be ' dewatered using drying beds. Figure 4.6 shows the flow schematic from this alternative. ' 9. Alternative C -4b This alternative is identical to Alternative C -4a, ex- cept that land application will be utilized in lieu of surface ' water discharge. Again, both nitrification and denitrification processes will be required. 10. Alternative C -5a This fifth alternative is a complete mix activated sludge ' treatment plant. Primary effluent is mixed with return acti- 4.39 vated sludge and introduced at several points in the aeration tank. This produces a complete mixing effect within the aera- tion tank, rather than the plug flow effect of the conventional activated sludge process. Sludge is removed from the clarifier ' and dewatered using sludge drying beds. The effluent will be 4.39 PRIMARY SEDIMENTATION TANK RAW WASTEWATER FROM COLLECTION J SYSTEM SCREENING AND GRIT REMOVAL LEGEND WASTEWATER 111.51111.11 SLUDGE ECO NDAR) LARI FIER DISINFECTION EFFLUENT TO OUTFALL OR LAND APPLICATION A LANDFILL GRAVITY��i ANAEROBIC 'HICKENER DIGESTER 11@40 DEWATERING 6 COMPOSTING EC INCINERATION ULTIMATE SLUDGE DISPOSAL CONTACT STABILIZATION ACTIVATED SLUDGE FLOW SCHEMATIC ALTERNATIVE C-4 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE. N V HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARPAINGOAIE f. CONSULTING ENGINEERS PLANNERS and ENVIRONMENTAL SCIENTISTS .jF ERti-A1 ��E ��r. T 0 -AD. '- CONTACT BASIN '. RAS AIR �"""',"' REAERATIO WAS TANK ECO NDAR) LARI FIER DISINFECTION EFFLUENT TO OUTFALL OR LAND APPLICATION A LANDFILL GRAVITY��i ANAEROBIC 'HICKENER DIGESTER 11@40 DEWATERING 6 COMPOSTING EC INCINERATION ULTIMATE SLUDGE DISPOSAL CONTACT STABILIZATION ACTIVATED SLUDGE FLOW SCHEMATIC ALTERNATIVE C-4 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE. N V HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARPAINGOAIE f. CONSULTING ENGINEERS PLANNERS and ENVIRONMENTAL SCIENTISTS .jF ERti-A1 ��E ��r. T 0 -AD. '- HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. discharged via an outfall to Long Island Sound or Peconic Bay. The flow schematic is shown on Figure 4.7. ' A complete mix activated sludge plant can operate at the highest BOD -5 load per unit volume aeration tank of any acti- vated sludge system. 11. Alternative C -5b This alternative is similar to Alternative C -5a, except ' that the effluent will be discharged using land application methods. Nitrification and denitrification will be required ' to meet effluent standards. 12. Alternative C-6 This alternative consists of a natural system of treat- ing domestic sewage by land application through marshes and ponds. Wastewater would receive preliminary treatment and then ' aeration. The flow would then be pumped intermittently into a marsh which would overflow into a pond. The pond effluent would be pumped to an area where ground infiltration through a vege- tated soil would take place. This process has been tested and has comparative effluent qualities with that of an advanced ' wastewater treatment (AWT) facility. The only end product of this process is the effluent water that is recharged into the ' ground. However, it should be noted that this process has seen limited use in the United States and that the long-term effects of this treatment process are unknown. Similarly, it is not known how the system will perform if the same land is used year 1 4.41 PRIMARY SEDIMENTATION TANK RAW ERATION ECONDA EFFLUENT WASTEWATER TANK CLARIFER TO OUTFALL OR LAND SCREENING DISINFECTION APPLICATION AND GRITz :RAS REMOVAL 14„•,,,, n.. •. •,,. • •,.,...,,, •.,..,,,.., •.,,,, WAS A LANDFILL GRAVITY logEE ROBIC HICKENo( DEWATERING IIIIIIIE B COMPOSTING T C INCINERATION LEGEND ULTIMATE WASTEWATER SLUDGE voloolloo•es, SLUDGE FLOW DISPOSAL COMPLETE MIX ACTIVATED SLUDGE FLOW SCHEMATIC ALTERNATIVE C-5 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE. N r HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FAPgyBti(GDALF CONSULTING ENGINEERS PLANNERS and ENVIRONMENTAL SCIENTISTS Fli'✓FRNEAO t. •F V.TO•. '. J -A r IHOLZMACHER, McLENOON and MURRELL. P.C. / H2M CORP. 11 ' after year. Therefore, the expected life of initial land is un- known. The flow schematic for the Marsh/Pond system is shown ' on Figure 4.8. B. Screening of Alternative Wastewater Treatment Processes ' Selection of a treatment process includes an evaluation of ' the ability of a process to treat the wastewater under the ex- pected conditions at the Mattituck plant. Using a list of ' operational characteristics of the various treatment processes on Table 4.2 and a list of advantages and disadvantages on Table ' 4.3, a comparison of the alternatives can be made using a matrix. A matrix was devised to display the various wastewater treat- ment processes and to serve as a guide for screening. This matrix ' provides a quantitative summary of judgments resulting from the screening of the qualitative information on Tables 4.2 and 4.3. ' The matrix, which has been generated as a result of eval- uating the alternative wastewater treatment processes described ' previously in this section, is presented on Table 4.4. ' This matrix functions on a series of discrete decisions. Each alternative is screened with respect to various factors and assessed a rating. The rating range depends on the screen- ing factor involved. For example, under the category of "Required Operator Skills", the factor is assessed as Minimal Skills (1), Good Skills (2), or Highly Skilled (3). This is similarly done for each item under the screening factor column. The ratings for ' all alternatives are arranged at the appropriate points in the matrix. Each column of the matrix is added to provide a total 1 4.43 RAW WASTEWATER FROM COLLECTION SYSTEM AERATED PONDS SCREENING AND GRIT REMOVAL OVERFLOW MARSH I POND AREA AREA MARSH/POND SYSTEM FLOW SCHEMATIC ALTERNATIVE C - 6 TOWN OF SOUTHOLD-INC. VILLAGE OF GREENPORT WASTE WATER FACILITIES STUDY VEGETATED RECHARGE AREA EFFLUENT TO GROUNDWATER F) c HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. CONSULTING ENGINEERS PLANNERS and ENVIRONMENTAL SCIENTISTS MELVILLE. N. V FAR1.41vC DALE N R'.FR`4FAD N v tiE'r. cr. rn Z to A CD TABLE 4.2 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT 4.45 OPERATIONAL CHARACTERISTICS OF VARIOUS TREATMENT PROCESSES PROCESS ITEM TRICKLING FILTERS ROTATING DISC ACTIVATED SLUDGE ACTIVATED SLUDGEl MARSH/POND (ALT. #0 (ALT. #2) (ALT. 73) (ALT. #4) (ALT. #6) (ALT. #5) Process Characteristics Reliability with respect to: Basic Process Good Good Very Good Fair Very Good Influent Flow Variations Fair Fair Good Fair Good Influent Load Variations Fair Fair Good Fair Good Presence of Industrial Waste Good Good Good Good Fair Industrial Shock Loadings Fair Fair Good Fair Fair Low Temperatures (<200C) Sensitive Sensitive Good Good Good (will not nitrify) (will not nitrify) Expandability to Meet: Increased Plant Loadings Good Good, must add Good, ultimately more Fai; to good if Fair, more land disc modules volume will be re- designed conserva- required quired tively More Stringent Discharge Requirements with respect to: SS Good, add filtration Good, add filtration Good, add filtration Good, add polishing Fair, add additional or polishing lagoons or polishing lagoons or polishing lagoons or polishing lagoons polishing trench BOD Improved by filtration Improved by filtration Improved by filtration Improved by filtration Fair, add additional polishing trench Nitrogen Good, denitrification Good, denitrification Good,denitrification Good, nitrification- Good, denitrificatirn must be added must be added must be added denitrification must be must be added added Operational Complexity(3) 2 2 3 4 1 Ease of Operation & Maintenance Very Good Very Good Very Good Fair Very Good Power Requirements (4) Moderately High Low Relatively High High Low 4.45 ITEM TABLE 4.2 (CONT'D) OPERATIONAL CHARACTERISTICS OF VARIOUS TREATMENT PROCESSES TRICKLING FILTERS (ALT. #1) Waste Products Sludges Potential Environmental Impacts Odors Site Considerations Land Area Requirements Moderate plus buffer zones Topography Relatively level ROTATING DISC r(ATL. =E2) Sludges Odors Moderate plus buffer zones Relatively level NOTES: 1Contact stabilization (Alt. #f4) and complete Mix (Alt. #5) 2Extended aeration (Alt. #3) 3Operational Complexity Range. . . (1 -simple) to (5 -complex) 4Power Requirements - Order of Intensity: Low Moderately High Relatively High High PROCESS ACTIVATED SLUDGE ALT. #3) Sludges Large plus buffer zone Relatively level ACTIVATED SLUDGEl (ALT. #4) (ALT. #5) Sludges Moderate plus buffer zone Relatively level MARSH/POND (ALT. #6) Possible clearing of marsh annually Odors Very large Relatively level COMPARISON FACTORS Expected BOD Removal Advantages Disadvantages ALTERNATIVE #1 75-90% TABLE 4.3 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT EVALUATION OF ALTERNATIVES ALTERNATIVE ALTERNATIVE ALTERNATIVE #2 43 44 85-95% 85-95% 85-95% -good with -low sludge -flexible BOD shock load production -resistant to -simple oper. -resistant to hydraulic load -little power organic & hydra. -simple oper. -fully nitrified loads -low cost -simple oper. -low sludge -low cost production -low BOD efficiency -sensitive to temperature -denit req'd for disigsal option -sensitive to temperature -sensitive to precipitation -denit- req' d for disposal option 'b" *Complete mix alternative only (alternative 5). -large oxygen requirements -limited expansion denit. req' d for disposal option 'b" -flexible -smaller aeration tank needed -no good on industrial waste -complex oper. -Nitro.-denit. needed for disposal option fib" 4.47 ALTERNATIVE #5 85-95% -very good on shock loads -high quality eff. . -constant bio conditioner -can handle scavenger waste* -complex oper. -nitro-denit. needed for disposal option fib## ALTERNATIVE 46 95% -no sludge production -can handle diluted scavenger waste -little knowledge on process -high land requirements -high O & M -denit. req'd for disposal option 'b" 7ABLE 4.4 GREENPnRT - SOUTHOLD 201 STUDY ALTER*1ATI`IES EVF.LUATI�^: E"�VIRO^I"iF"iTAL ASSESSMENT REPORT SCREENING OF ALTERNATIVE WASTEWATER TREATMENT PROCESSES ALT. ALT. ALT. ALT. ALT. ALT. ALT. C -la & C -2a & C -3a & C -4a & C -5a & C-6 B SCREENING FACTORS C -lb C -2b C -3b C -4b C-5b(PL ' MPING) Abatement of Existing 4 4 4 4 4 4 0 Water Pollution Problems Achieve Water Quality NG 0 0 0 0 0 0 Goals for Outfall or Groundwater Recharge Monetary Costs 3 2 4 4 3 NG Process Reliability 2 1 2 2 1 Stability of Waste Sludge 2 2 2 2 0 Required Operator 1 2 3 3 1 Skills Power Requirements 2 3 3 3 2 Advantages -2 -2.5 -1 -1.5 -1.5 Disadvantages 4 4 6 4 6 TOTALS NG 16 15.5 23 20.5 15.5" NG LEGEND: 1. NG - denotes that the alternative will not be compared with the remaining alternatives due to the reason(s) cited in the report. 2. N/A - Not Applicable. 3. Abatement of Existing Water Pollution. Problems: Resolved -0, Significant -4, Moderate -6, Minimal -8, Insignificant -NG. 4. Achieve Water Quality Goals for Outfall or Groundwater Recharge: Compliance -0, Moderate Compliance -6, Minimal Compliance -8, :von -Compliance -NG. 5. Monetary Costs: Minimal -1, Moderate -2, Significant -3, Expensive -4, Very Expensive -8. 6. Process Reliability: Reliable -1, Conditional -2, Unreliable -3. 7. Stability of Waste Sludge: Very Stable -1, Stable -2, Unstable -3, No Sludge -0. 8. Required Operator Skills: Minimal Skills -1, Good Skills -2, Highly Skilled -1. 9. Power Requirements: Low -1, Moderate -2, High -3. 10. Advantages: Number of advantages x (- 0.5). 11. Disadvantages: Number of disadvantages x (2). 4.48 HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. for each alternative. This sum will then be compared with each ' sum of the various alternatives. The detailed analyses which provide the substantiation for each of the judgments in the ma- trix is contained in the following subsections: ' 1. Alternative B The pumping of wastewater from Mattituck to Greenport was ' considered as an alternative, in order to try and utilize the ' excess capacity at the Greenport STP for economic reasons. How- ever, further examination of this alternative indicates that the ' capital construction and annual O & M costs of providing for a 13 mile force main with two (2) pump stations, in addition to ' expansion of the Greenport Sewage Treatment Plant, is extremely expensive. For this reason, further consideration of this al- ternative has been eliminated. ' 2. Alternatives C -la and C -1B Since both of these alternatives will not consistently achieve the effluent quality limitation expected to be set by the discharge permit, they were assigned a rating of NG. Thus, Alternatives C -la and C -lb are eliminated from further consid- eration. 3. Alternatives C -2a and C -2b ' The use of rotating biological discs, together with sett- ling clarifiers as a treatment facility, would be an appropriate 1 selection for a Mattituck treatment plant. The somewhat simple ' operational complexity, together with a relatively low cost, ex- tends the suitability of this process for the Mattituck area. 1 4.49 ' HOLZMACHER, MCLENOON and MURRELL, P.C. / H2M CORP. for each alternative. This sum will then be compared with each ' sum of the various alternatives• The detailed analyses which provide the substantiation for each of the judgments in the ma- trix is contained in the following subsections: 1. Alternative B The pumping of wastewater from Mattituck to Greenport was ' considered as an alternative, in order to try and utilize the ' excess capacity at the Greenport STP for economic reasons. How- ever, further examination of this alternative indicates that the ' capital construction and annual O & M costs of providing for a 13 mile force main with two (2) pump stations, in addition to ' expansion of the Greenport Sewage Treatment Plant, is extremely expensive. For this reason, further consideration of this al- ternative has been eliminated. ' 2. Alternatives C -la and C -1B Since both of these alternatives will not consistently achieve the effluent quality limitation expected to be set by the discharge permit, they were assigned a rating of NG. Thus, ' Alternatives C -la and C -lb are eliminated from further consid- eration. 3. Alternatives C -2a and C -2b The use of rotating biological discs, together with sett- ling clarifiers as a treatment facility, would be an appropriate ' selection for a Mattituck treatment plant. The somewhat simple ' operational complexity, together with a relatively low cost, ex- tends the suitability of this process for the Mattituck area. 1 4.49 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' The total estimated annual cost is $287,700. for C -2a and $346,200. for C -2b. ' The screening factors were evaluated as follows: I. Abatement of Existing Water Pollution Problems: 4 - Significant 2. Achieve Water Quality Goals for Discharge: 0 - Compliance 3. Monetary Costs: 3 - Significant 4. Process Reliability: 2 - Conditional 5. Stability of. Waste Sludge: 2 - Stable ' 6. Required Operator Skills: 1 - Minimal Skills ' 7. Power Requirements: 2 - Moderate B. Advantages: 4 x -.5 = -2 _=low sludge production resistant to organic and hydraulic loads simple operations -- low cost ' 9. Disadvantages: 2 x 2 = 4 -- sensitive to temperature ' -- sensitive to precipitation 10. Total . . . . . . . . . . . . . . . 16 ' 4. Alternatives C3a and C -3b The activated sludge process using extended aeration is a ' feasible facility for a small community wastewater treatment ' plant. A high efficiency of BOD -5 and Suspended Solids re- moval together with a relatively low cost makes extended aera- tion appropriate for the Mattituck plant. The total estimated annual cost is $235,300. for C -3a and $292,900. for C -3b. ' The screening factors were evaluated as follows: 4.50 1 1 1 1 1 1 1 1 1 1 1 1 1 1 HOLZMACHER, McLENDON and MURREL.L, P.C. / H2M CORP. 1. Abatement of Existing Water Pollution Problems: 2. Achieve Water Quality Goals for Discharge: 3. Monetary Costs: 4. Process Reliability: 5. Stability of Waste Sludge: 6. Required Operator Skills: 7. Power Requirements: 8. Advantages: 5 x -.5 = -2.5 -- flexible -- resistant to hydraulic load -- simple operations -- low sludge production -- low cost 9. Disadvantages: 2 x 2 = 4 -- large oxygen requirements -- limited expansion 4 - Significant 0 - Compliance 2 - Moderate 1 - Reliable 2 - Stable 2 - Good Skills 3 - High 10. Total . . . . . . . . . . . . . . . . . 15.5 5. Alternatives C -4a and C -4b Contact stabilization activated sludge treatment process will obtain a high quality effluent, but at a relatively high cost. Total estimated annual cost is $395,900. for C -4a and $452,800. for C -4b. The screening factors were evaluated as follows: 1. Abatement of Existing Water Pollution Problems: 4 - Significant 2. Achieve Water Quality Goals for Discharge: 0 - Compliance 3. Monetary Costs: 4 - Expensive 4. Process Reliability: 2 - Conditional 4.51 ' HOLZMACHER, MCLENDON and MURRELL, P.C. i H2M CORP. ' 5. Stability of Waste Sludge: 2 - Stable 6. Required Operator Skills: 3 - Highly Skilled ' 7. Power Requirements: 3 - High 8. Advantages: 2 x -.5 = -1 flexible - smaller aeration tank needed 9. Disadvantages: 3 x 2 = 6 - no good on industrial wastes -- complex operation ' -- nitrification needed prior to denitrification 10. Total . . . . . . . . . . . . . . . 23 ' 6. Alternatives C-5a C-5b and Complete mix activated sludge for the secondary treatment facility proposed at Mattituck will obtain a high quality efflu- ent, but at a relatively high cost. If scavenger waste is to be disposed of at the treatment plant, this alternative will be feasible because its to handle high BOD a process of ability loadings. The total estimated annual cost is $395,900. for C-5a and $452,800. for C-5b. ' The screening factors were evaluated as follows: 1. Abatement of Existing Water ' Pollution Problems: 4 - Significant 2. Achieve Water Quality Goals for Discharge: 0 - Compliance ' 3. Monetary Costs: 4 Expensive ' 4. Process Reliability: 2 - Conditional 5. Stability of Waste Sludge: 2 - Stable 6. Required Operator Skills: 3 - Highly Skilled 7. Power Requirements: 3 - High ' 4.52 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. ' 8. Advantages: 3 x -.5 = -1.5 very good on BOD loading -- high quality effluent -- constant biological conditions ' 9. Disadvantages: 2 x 2 = 4 -- complex operation ' -- nitrification needed prior to denitrification 10. Total . . . . . . . . . . . . . . . . . 20.5 ' 7. Alternative C-6 The marsh/pond system of treating wastewater is a very ad- vantageous process. High quality effluent water is easily at- tended without sludge as a by-product. However, little data ' are available on how the system will fair after 20 years of service. Will the soil characteristics deteriorate over this ' period? A lack of information makes it questionable if this system should be used. Excessive land requirements of the ' marsh/pond system results in a large initial cost. The total estimated annual cost is $358,700. for Alternative C-6. ' The screening factors were evaluated as follows: 1. Abatement of Existing Water Pollution Problems: 4 - Significant 2. Achieve Water Quality Goals ' for Discharge: 0 - Compliance 3. Monetary Costs: 3 - Significant ' 4. Process Reliability: 1 - Reliable ' 5. Stability of Waste Sludge: 0 - No Sludge 6. Required Operator Skills: 1 - Minimal Skills 7. Power Requirements: 2 - Moderate [1 ' 4.53 0 FI HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 8. Advantages: 3 x -.5 = -1.5 -- no sludge production -- can handle scavenger waste -- high quality effluent 9. Disadvantages: 3 x 2 = 6 -- little knowledge on process -- high land requirements -- high operation and maintenance costs 10. Total . . . . . . . . . . . . . . . . . 15.5 4.2.4 Wastewater Treatment and Reuse Conventional means of effluent disposal on Long Island is through surface water discharge. The existing Greenport STP utilizes a Sound outfall. A Mattituck facility could possibly use a Sound or Ray outfall. However, with the study area only having one source of potable water, the alternative of wastewater reuse at either facility will be examined in order to conserve the limited groundwater resource. In most instances, it is generally not feasible to reuse a treated wastewater effluent completely or indefinitely. The reuse of treated effluents by direct or indirect means is a method of disposal. which invariably complements another dis- posal method. Usually the parameters which serve to control the amount of effluent that can be reused include: (a) avail- ability and cost of potable/irrigation water; (b) transportation and treatment costs of wastewater; and (c) water quality standards. Water reuse is generally classified according to use as follows: (1) Municipal Reuse - Treated wastewater may be used as drinking water after dilution in natural waters, i.e. rivers 4.54 r� L 1 r 1 7 L NOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. or streams. After dilution, the water is treated by coagula- tion, filtration and heavy chlorination for disinfection and then may be used for drinking water, most practicable on an emergency basis only. This practice is very similar to the situation existing on many rivers that are used for both water supply and waste disposal with the only variation being the degree of water treatment. In municipalities where inadequate water supplies exist, it may be necessary to employ advanced methods of wastewater and water treatment. These methods are capable of almost com- plete removal of impurities. Further, water treated by these methods, after disinfection, is safe to drink. However, these methods are extremely expensive and where they are found to be absolutely necessary, may be economically feasible only if a dual supply system is adopted. For example, adequately treated effluent could be reused for toilet flushing, lawn watering, park or golf course watering or other similar applications. (2) Industrial Reuse - Presently, the reuse of treated municipal wastewaters by industry is small, but the practice is on the rise. The increasing number of examples where this is carried out attests to the enormous future potential that exists. Properly treated wastewater can be used successfully for general plant application, for cooling water and also boiler feed -water. Since approximately 50 percent of all industrial water use falls within the latter two categories, it can be said that the value of treated wastewater to industry is 4.55 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 1 significant. However, treated wastewater is used industrially ' in areas where economic conditions make treatment and reuse a ' favorable choice. Generally, the factors which must be considered in deciding ' on the practicality of the reuse of wastewater plant effluent by industry are the following: A. An industry in the locality must exhibit the need for a process water which does not involve a risk to public health. (Not directly utilized in end ' product.) B. Processing costs, including wastewater trans- portation and pumping, must not exceed those of an alternate supply. ' C. The quality of the wastewater plant effluent should be consistent enough to allow its day- to-day use by the particular industry. ' Further, it has been found that the requirements for water used in industry are highly variable. Because of this, and ' the variability in quality of wastewater effluents, the neces- sary degree of treatment should usually be determined on an individual industry basis. Consequently, the cost of treating ' the water for industrial use is also variable with the particular circumstances. (3) Agricultural Reuse - Irrigation of lands with waste- water has been practiced for centuries. In certain instances, the objective is to simply dispose of the wastewater, however, ' in other instances the primary purpose is the production of crops and the raising of animals. In the United States, the practise of irrigating with treated municipal wastewaters is ' usually confined to arid or semi -arid areas. 4.56 INOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' etc., cannot be irrigated with wastewater of any kind with the only exception being the use of a well oxidized, non-putrescible ' and reliably disinfected or filtered treated wastewater which always meets strict bacterial content standards. ' Preliminary treated or undisinfected wastewater effluent is ' usually allowed for: (a) field crops such as cotton, flax, sugar beets or vegetables grown for seed production; (b) for animal ' feed and pasture crops; (c) for woodlands; and (d) for a variety of other crops where wastewater irrigation will not affect the public health. In semi -arid or arid areas where water is generally scarce and often difficult to obtain in extremely dry years, a size- able supplementary water supply can often be derived from waste- water flows. A major obstacle is that the large population con- centrations are usually located considerable distances from farm lands. Under these circumstances, transportation costs might make it uneconomical to use the treated wastewater for agri- cultural purposes. However, where municipalities are located near farm lands, the practice might prove to be highly economical. 1 4.57 The types of crops that can be irrigated with treated waste- water usually depend on: (a) the quality and quantity of waste- water; and (b) the local, State or Federal. health regulations governing the use of the wastewater or treated wastewater on the ' crops. Health considerations in the United States have dictated negligible use of raw wastewater. In addition, field crops nor- mally consumed in the raw state, i.e. lettuce, escarole, tomatoes, ' etc., cannot be irrigated with wastewater of any kind with the only exception being the use of a well oxidized, non-putrescible ' and reliably disinfected or filtered treated wastewater which always meets strict bacterial content standards. ' Preliminary treated or undisinfected wastewater effluent is ' usually allowed for: (a) field crops such as cotton, flax, sugar beets or vegetables grown for seed production; (b) for animal ' feed and pasture crops; (c) for woodlands; and (d) for a variety of other crops where wastewater irrigation will not affect the public health. In semi -arid or arid areas where water is generally scarce and often difficult to obtain in extremely dry years, a size- able supplementary water supply can often be derived from waste- water flows. A major obstacle is that the large population con- centrations are usually located considerable distances from farm lands. Under these circumstances, transportation costs might make it uneconomical to use the treated wastewater for agri- cultural purposes. However, where municipalities are located near farm lands, the practice might prove to be highly economical. 1 4.57 IHOLZMACHER, McLENDON •nd MURRELL, P.C. / HZM CORP. (4) Recreational Reuse - The watering of golf courses, park ' watering, establishment of ponds for boating and recreation, and ' maintenance of fish or wildlife ponds are some of the methods em- ployed for recreational reuse of treated wastewater. Considering ' the emphasis being placed on the recreational use of our water re- sources today, there appears to be little doubt that the increased ' development of facilities of this nature will be forthcoming in ' the future. Further, today's technology permits the production of a well suited treated wastewater for the purposes described ' above. Finally, the watering of parks with treated wastewater has been practiced for many years in this country and there is no ' viable technological reason which dictates that it should not continue. (5) Groundwater Recharge - Replenishment of groundwater supplies by groundwater recharge is one of the most common ' methods for combining water reuse and effluent disposal. Today, recharging is being practiced in many areas especially in those where the natural groundwater tables are rapidly falling or ' are being contaminated with salt water or nutrients. In Long Island, (New York), California and other coastal ' areas, rapid development of industry in conjunction with in- creased residential development have caused a lowering of the natural groundwater table, resulting in salt water intrusion ' into the fresh water aquifers along the coastline. Consequently, treated wastewater is being considered or used to replenish the groundwater and halt this intrusion in these areas. 1 4.58 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. Some of the many advantages gained by groundwater recharge ' are the following: A. Control of salt water (saline) intrusion. ' B. Reduction of aquifer overdrafts. ' C. Supplementing natural recharge where man's activities have reduced or eliminated recharge. (6) Evaluation of Wastewater Reuse - At the present time, ' wastewater reuse to some degree is a viable alternative in the ' Town of Southold - Inc. Village of Greenport. Reuse of waste- water by land application on agricultural or recreational tracts ' is recommended. A further evaluation of this alternative is ad- dressed in the following subsection entitled "Land Application". Direct reuse of wastewater as a potable water supply is ex- tremely expensive and consequently not economically feasible at this time. ' 4.2.5 Land Application ' The Greenport STP is presently discharging its effluent through an outfall to Long Island Sound. With the deterioration ' of the groundwater quality within the vicinity of the Greenport water supply area, we have investigated the feasibility of land application of effluent. Recharge of effluent to the aquifer ' could have the effect of reversing the trend in groundwater contamination due to chlorides from salt water intrusion and ' lowering the nitrate concentration of the groundwater. Land application (disposal) systems can be divided into ' three categories or classifications. These are: (1) spray irri- gation; (2) infiltration/percolation; and (3) overland flow. ' 4.59 ' HOLZMACHER, McLENDON and MURRELL, P -C, / H2M CORP. 1 These three methods are shown schematically in Figure 4.9 and comparative characteristics are given in Table 4.5. (1) Spray Irrigation - This is the most popular of the land application techniques and the most reliable. This method tinvolves applying wastewater to land, either by spraying or sur- face spreading. Supporting plant growth and treating the waste- water are the results of this technique. Treatment is accomplished by physical., chemical and bio- logical means as the wastewater seeps through the soil. Irri- gation systems are usually designed to accomplish the following ' purposes: A. To avoid the discharge of nutrients into surface waters. B. To obtain economic return from the use of waste- water nutrients for producing marketable crops, ' if feasible. C. To conserve water by utilizing wastewater for lawns, parks or golf courses. D. To preserve and enlarge green belts and open space. Pre -application treatment of wastewater is required for most irrigation systems and a wide range of treatment requirements are 1 encountered. The bacteriological quality of wastewater is usually a limiting factor where food crops or landscapes are to be irri- gated. In other instances, reduction in BOD and SS may be neces- sary to prevent clogging of distribution nozzles or to prevent generation of odors. 1 1 4.60 SPRAY OR SURFACE APPLICATI( ROOT ZOO SUBSOIL EVAPOTRANSPIRATION IA) IRRIGATION EVAPORATION t / SPRAY OR SURFACE APPLICATION r IUUKt 4.9 'ARIABLE LOPE DEEP PERCOLATION SPRAY APPLICATION EVAPOTRANSPIRATION /� --�� T GRASS AND VEGETATIVE LITTER /11 1 N RUNOFF COLLECTION PERCOLATION 1-4 100.300 FT (C) OVERLAND FLOW SW LAND TREATMENT OF MUNICIPAL WASTEWATER EFFLUENTS USEPA TECHNOLOGY TRANSFER JANUARY 1976 LAND APPLICATION METHODS TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY M[LVILL E4N. Y. HOLLMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMNGDALE N V CONSULTING ENGINEERS PLANNERS and ENVIRONMENTAL SCIENTISTS RIVERFiEAD N v NE WT.IN. N J 4.61 TABLE 4.5 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION &ENVIRONMFNTAL ASSESSMENT RFPORT COMPARATIVF. CHARACTERISTICS OF IRRIGATION OVERLAND FLOW AND INFILTRATION/PERCOLATION SYSTFMS TYPE OF APPROACH INFILTRATION/ FACTOR IRRIGATION OVERLAND FLOW PERCOLATION Liquid Loading Rate** Annual Appli- cation Land Required for 1.0 mgd Flow Application Techniques soils Probability of Influencing Groundwater Quality Needed Depth to Groundwater 0.5-4.0 in/wk 2.0-8.0 ft/yr 140-560 acres plus buffer zones Spray or surface Moderately per- meable soils with good pro- ductivity when irrigated Moderate About 5.0 ft. 2.0-5.5 in/wk 4.0-120.0 in/wk 8.0-24.0 ft/yr 18.0-500.0 ft/yr 46-140 acres 2-62 acres plus plus buffer buffer zones zones Usually spray Usually surface Slowly perme- Rapidly permeable able soils such soils such as as clay loams sands, loamy sands, and clay and sandy foams Slight Certain Undetermined About 15.0 ft Wastewater Predominantly Surface dis- Percolation to Lost to evaporation or charge domin- groundwater deep percolation ates over eva- poration & per- colation **Irrigation rates of 4.0 in/wk are usually seasonal; yearly maximum loads of 8.0 ft/yr would average about 2.0 in/wk. SOURCE: USEPA 4.62 1 Li 0 HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. Essential to all land application techniques is the need for suitable site characteristics. Table 4.6 summarizes the basic site characteristics required for the land application techniques. Other considerations which should not be disregarded in irri- gation systems are the hydraulic and nitrogen loading rates. In most cases, one of these factors will be a limiting factor. How- ever, in special cases other loading rates such as phosphorus and organic matter, or loadings of constituents of abnormally high concentration, may be more critical. In order to obtain loading rates, water and constituent balances must usually be performed. In conducting the water balance, the factors of primary con- cern are: (a) the quantity of wastewater applied; (b) precipita- tion; (c) evapotranspiration; (d) percolation; and (e) runoff. In conducting the constituent (nitrogen or other nutrient) balance, the amount of constituent applied in the wastewater per year is compared to the amount taken up (uptake) by a particular crop (grass or other vegetation), and the amount that passes through to the groundwater. The farming operations within the Township increase the suitability of the alternative of effluent irrigation. Major crops produced in Southold are potatoes, cauliflower and sod. The use of effluent on potatoes is not recommended because tuberous crops have a potentially high probability of contami- nation from pathogenic bacteria and viruses. Effluent irrigation of cauliflower crops is not an acceptable practice because of its 4.63 ' TABLE 4.6 GRFENPORT - SOUTHOLD 201 STUDY ALTERNATIVE'S FVALUATION &ENVIRONMENTAL ASSESSMENT REPORT SITE CHARACTERISTICS FOR LAND DISPOSAL OF WASTEWATER SITE APPLICATION TFCHNI.UF.S CHARACTERISTIC SPRAY OVERLAND INFILTRATION/ ' CONSIDERATION IRRIGATION FLOW PERCOLATION Climate Warm to arid prefer- Same as spray All climates red. Severe climates acceptable only if irrigation. acceptable. Loadings may need adequate storage is to be reduced provided for wet or for cold weather. freezing conditions. Topography Slopes up to 15% for Rolling terrain-- Level terrain pre - crop irrigation are level terrain can ferred--rolling acceptable. Runoff be used to create terrain acceptable. or erosion should be uniform slopes 2 controlled. to 6%,in some cases as high as 8% Soil Type Loamy soils prefer- Clay and clay Acceptable soils red. Sandy loams to loams preferred include sand, ' clay loams are suit- sandy loams, loamy able. soils and grave]. ' Soil Drainage Well drained is pre- Poor or slow Moderate to rapid ferred. Poorly drain- drainage preferred, drainage. ed is suitable if ' drainage features are included in de- sign. r 4.64 TABLE 4.6 (CONT -D) S'rTF CHARACTFRTSTTc'S FOR LANK OF WASTF.WATFR SITE CHARACTFRISTIC SPRAY CONE'.TDFRATION IRRIGATION Soil Depth At least. 6-8 ft. or more for most de- velopment and/or wastewater renova- tion. Geologic Should not contain Formation major discontinu- ities which provide short circuits to groundwater. Groundwater Minimum depth to groundwater should be 5 ft. APPLICATION TF.CHNIQUFS OVFPLANT? TNFTLTRATION/ FLOW P F: R C'OLA`P ION Depth must be Uni form depth of 15 sufficient to ft. is preferred. form slopes and maintain vegeta- tive cover. (about 2 ft.) Same as spray Same as spray irrigation. irrigation. Groundwater should not interefere with plant growth. (About 2 ft.) ) A minimum of 15 ft. to the high water table is required. IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. short growing season and direct digestion into the human food chain. The four month season limits the use of irrigation and ' would not justify the cost of transporting the effluent froin the sewage treatment plant to the farm. Recent studies performed by ' Pennsylvania State University, have shown that a sod crop of reed canary grass is a very suitable crop for effluent irrigation. The nitrogen loading of the effluent applied at the rate of 2 in/wk provided enough nutrients to the grass that the application of fertilizer was not necessary to obtain equivalent ;iel.ds. The efficiency of sod as a wastewater renovating agent was assessed by computing a removal efficiency expressed as the ratio of the ' weight of nitrogen removed .in the harvested crop (clippings) to The average concentration of nitrate in the control plot of reed canary grass receiving applications of commercial fertilizer ' was 0.2 mg/1. This study, therefore, shows that effluent can re- place the use of fertilizers, however, a more significant nitrate ' concentration leaches to the groundwater from effluent rather than ' fertilizers. In trying to relate the data of this study to the present ' conditions of the sod farms located in Southold, certain dif- ferences should be noted. Merion bluegrass is grown instead of 1 4.66 the weight of the nitrogen applied in the wastewater. An average of over 97 percent removal efficiency was obtained through the six (6) year study period. Average concentrations of nitrate -N in the percolate at the four (4) foot soil depth was 3.5 mg/1 in the effluent irrigated areas. The average concentration of nitrate in the control plot of reed canary grass receiving applications of commercial fertilizer ' was 0.2 mg/1. This study, therefore, shows that effluent can re- place the use of fertilizers, however, a more significant nitrate ' concentration leaches to the groundwater from effluent rather than ' fertilizers. In trying to relate the data of this study to the present ' conditions of the sod farms located in Southold, certain dif- ferences should be noted. Merion bluegrass is grown instead of 1 4.66 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. reed canary grass. This condition could have a significant ' change in results of effluent irrigation due to the different ' characteristics of grass types. It is suggested that a pilot plant study be performed using existing conditions before going ' to a full scale irrigation system. Effluent irrigation will help conserve the groundwater supply. However, the additional. nitrate input will further ' deteriorate the water quality of the aquifer, which cannot be tolerated. It would be possible to apply the effluent at very low nitrogen loadings, thereby allowing optional uptake from the turf and minimal leaching of nitrogen. This, however, will require either a denitrification process at the treatment fa- cility or a blending procedure of effluent with irrigation water prior to the irrigation method. ' Another major concern when using effluent irrigation is that of public health considerations. Spray irrigation trans- ports pathogenic bacteria and viruses out of the immediate area. Recent studies have found that the median size of viable parti- cles collected downwind from effluent spray was 5 microns. This is important because this size particle is subject to inhalation by humans. Modifications and precautions must be taken to mini- mize aerosol dispersement. ' One major disadvantage of effluent irrigation for the Green- port/Southold study area is that of a short growing season. Ef- fluent irrigation can only be utilized during the growing season which lasts approximately 190 days (April through September) per 1 4.67 HOLZMACHER, McLENDON and MURRELL, P.C. I H2M CORP. ' year. Therefore, an alternate disposal method would have to be employed during the remainder of the year. For the Greenport facility, the existing outfall is most appropriate for utili- zation during the winter months, if a dual discharge permit ' could be obtained. Effluent irrigation at a Mattituck sub - regional treatment facility is somewhat unlikely due to the prohibitive estimated capital construction cost of providing ' two separate effluent disposal systems. (2) Infiltration/Percolation - In this method, wastewater ' is usually applied to the soil by spreading in basins and is treated as it travels downward through the soil. Vegetation is generally not used, although grass may be placed at the bottom and sides of the basins. Pre -application treatment is performed to reduce the SS content, and thereby allows the continuation of high application rates. Biological treatment is most often recom- mended prior to spreading, although effluent with only primary ' treatment has been used. Once again, treatment is accomplished ' by physical, chemical and biological means. Since most of the applied effluent percolates through the soil, soil drainage is usually the limiting site characteristic. Other site evaluation criteria are summarized in Table 4.6. Loading rates, liquid or nitrogen, should be considered ' limiting factors for this treatment technique. However, load- ings of salt as a result of weathering and soil lime dissolution ' may be critical in some cases. Basin loading schedules and al- ternating loading and resting periods are required to restore 1 4.68 IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. the infiltration capability of the soil surface and to promote ' optimum nitrogen removal by nitrification -denitrification. ' The water balance for this treatment technique is similar to that for irrigation, except that greater quantities of water ' are undoubtedly lost to percolation. The limiting percolation rate should be estimated for saturated soil and adverse climatic conditions. Runoff is not a consideration in this treatment ' method. Lastly, where concentrations of nitrogen compounds (es- pecially nitrates) in the groundwater are a limiting factor, the wastewater loading rate and/or schedule must be established to maximize denitrification. Previous studies have shown that infiltration/percolation techniques can only obtain approximately 80 percent nitrogen ' removal. This would reduce the nitrate concentration of the recharge to about 6 mg/l. It is felt that this concentration is still too high to recharge directly into the groundwater. There- fore, a nitrification -denitrification process will be required to reduce the nitrate concentration before land application. This in turn will increase the total cost of treatment. Methods for increasing nitrogen removal through land applications are ' being tested using different management systems which include reduction of infiltration rates or recycling high nitrate per- colate. These techniques for achieving high nitrogen removal, ' although promising, require testing on a field scale before widespread adaption. 1 4.69 7 Ll n HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. Advantages of this technique are the considerable amount of groundwater recharge obtainable and the adaptation to cold cli- mates. With groundwater quality being degraded by salt water intrusion, groundwater recharge can reverse the hydraulic gra- dient and protect the existing aquifer. Site selection is of utmost importance for this method to be efficient. With salt water intrusion being apparent at Well Field No. 4, an infil- tration basin should be located within close proximity to the wells. The adaptation of infiltration/percolation to cold cli- mate lends the method for year-round operation unlike the other methods. (3) Overland Flow - In this technique, wastewater is ap- plied to the upper reaches of sloped terraces and allowed to flow across a vegetated surface to runoff collection ditches. Soils should be relatively impermeable. Treatment is ac- complished by physical, chemical and biological means as the wastewater flows uniformly through the grass and vegetative cover. Pre -application of wastewater, at minimum, should in- clude removal of solids, grit and grease which generally hamper effective sprinkling application. If pre -application treatment includes secondary treatment, overland flow can be used for polishing of the effluent and the removal of nitrogen compounds. Recommended site characteristics for this method of treat- ment are summarized in Table 4.6. Loading rates should be determined for primary and secondary treated wastewaters. A water balance is conducted to estimate 4.70 IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. the expected runoff. The required length of runoff terrace is usually dependent on the degree of treatment required, wastewater characteristics, climate and slope of land. Once again, the effluent must go through a nitrification - denitrification process to remove all of the nitrogen so not to have nitrates leaching into the groundwater. It also has been ' observed that operational efficiency decreases in cold climates. ' (4) Environmental Considerations - Land application of treated effluent is desirable in some cases and in certain geo- graphical areas because it may serve to fertilize and irrigate cropland, recharge and conserve groundwater and provide or in- crease the buffer between the fresh -salt water interface. The ' environmental shortcomings of land application disposal tech- niques are: A. Relatively large amount of suitable land is needed for application. ' A. Large areas are needed for storage lagoons. C. Undesirable odors may be generated. ' D. Energy consumption to operate land application techniques is greater than a surface water outfall. ' E. There may be a potential hazard to public health from airborne pathogens and contaminated food crops. F. Operating costs are significantly greater than ' for a surface water outfall. G. There may be a potential impart upon groundwater quality. ' H. Surface waters may be adversely impacted by run- off from application sites. 1 4.71 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. 11 ' (5) Evaluation of Land Application - After a thorough ex- amination of all land application techniques, it is determined ' that the most feasible disposal alternatives for the Greenport ' STP's effluent are: A. Irrigation of a sod farm. ' B. Infiltration/percolation. Effluent irrigation on a sod crop would be the most ac- ceptable method, only if the amount of nitrate leaching to the ' groundwater is less than that leaching from fertilizer practices. In order to determine if a reduction in nitrate percolation can ' be achieved, it is suggested that a pilot plant study be initiated. If proven acceptable, full scale irrigation can be developed for ' either existing privately -owned sod farms or a new farm be pur- chased and operated by the Inc. Village of Greenport. Infiltration/percolation is an acceptable disposal method ' that will recharge groundwater with up to 90 percent of the ef- fluent applied to the land. Selection of a site location is in- fluential in preventing salt water intrusion. This method will, ' however, require the addition of a nitrification -denitrification process prior to land application. The additional cost of treat- ment will be reflected in the cost-effective analysis of alter- natives in Section 5.0. Previous studies at Greenport indicate ' the presence of a extensive clay layer near the treatment plant. ' As a result, some pumping will be required to reach a satisfactory site. 1 1 4.72 HOLZMACHER, McLENDON and MURRELL, P.C. / HZM CORP. 4.2.6 _ Surface Water Discharge ' Surface water effluent disposal is typically accomplished ' by submarine outfalls that transport the sewage some distance from shore prior to discharging the wastewater to the receiving waters. At the end of the outfall, the wastewater is released in a single stream or equally distributed via a manifold or ' multiple point diffuser. The combination of dispersion and dilution provides an effective effluent disposal method with ' Little impact on the surrounding environment. ' The Inc. Village of Greenport Sewage Treatment Plant cur- rently utilizes a Long Island Sound outfall to dispose of the ' effluent water. Due to the minute volume of discharge rela- tive to the volume of receiving waters, the constituents remain- ing in the wastewater become highly diluted. The Sound remains 'relatively unimpacted due to a good exchange with the Atlantic Ocean. Harvesting of shellfish is prohibited within the closure ' area around the outfall in order to rule out any possible chances of contamination. As long as the sewage treatment plant con- tinues to conform to the effluent limitation set by NYSDEC, ' there will be few adverse affects on the surrounding environ- ment. Coliform tests were performed on samples obtained from beaches in close proximity to the outfall and results have shown the water quality of the beaches to be in excellent 'condition. (1) il) 1977 Bathing Beach Water Quality Report, SCDHS 4.73 G 1 r 0 0 i C 1 L 11 11 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. Other discharge points, such as Gardiners Bay, may be an equally attractive outfall location. However, since there are no significant environmental impacts due to the existing out- fall, there is no reason to choose an alternate surface water discharge site. Surface water discharge, as currently practiced, is the most cost-effective method of effluent disposal. However, with the increase in salt water intrusion within the Southold/Green- port area, it may be advantageous to artificially recharge the groundwater aquifer in order to retard salt water intrusion and increase recharge. Surface water discharge is also feasible for the Mattituck sub -regional facility. Since an exact location for this fa- cility has not been selected, the discharge location can not be determined. Possible receiving waters are: 1) Long Island Sound; 2) Mattituck Creek; and 3) Peconic Bay. As previously discussed, a Sound outfall would provide optimal conditions for effective dilution and dispersion. However, if a facility lo- cation is selected on the south shore of Southold, it would be more cost-effective to discharge into Peconic Bay rather than to the Sound. The Peconic Bay also provides sufficient dilu- tion characteristics to receive the waste load. Mattituck Creek, however, does not receive sufficient tidal flushing to be able to accept the flow from the Mattituck area. Once a site is determined for the Mattituck Treatment Facility, a cost-effective analysis will be required prior to selecting a discharge location. 4.74 ' HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. ' 4.3 Description of Alternative Sludge Treatment and Disposal Processes ' For the purpose of this report, sludge treatment alterna- tives will be examined under two separate sub -groupings, (a) sludge treatment methods and (b) ultimate disposal methods. ' This section provides a brief description of each of the specific sludge treatment and disposal processes which might ' be utilized for either the Greenport Sewage Treatment Plant or a sub -regional wastewater management plan which would in- clude the Greenport plant and one or more additional waste- water facilities within the Township. One of the most important factors that must be examined ' when analyzing sludge treatment and disposal alternatives is the quantity of sludge to be handled. In determining a design flow for a facility, present and future sludge volumes have to ' be estimated. Table 4.7 summarizes the estimated sludge vol- umes from the Inc. Village of Greenport STP, scavenger waste ' from Southold and Shelter Island, and sludge volumes from the Shelter Island Heights Association STP. No consideration is ' given to the sludge produced from a plant to be constructed at ' Mattituck. However, scavenger waste from the Mattituck area is included which would be replaced by sludge produced from a ' Mattituck Plant, if such were constructed. 1 4.75 MUNICIPALITY Inc. Village of Greenport Town of Southold Town of Shelter Island (3) TABLE 4.7 GREENPOF,T - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT TYPE OF WASTE Wastewater Scavenger Waste (2) Wastewater Scavenger Waste TOTALS (dry solids) ESTIMATED SLUDGE VOLUMES PRESENT PRESENT FLOW SLUDGE (1) (GPD) (LBS/DAY) 260,000 369 TOTALS AT 5% SOLIDS 4,200 144 20,000 28 710 24 565 lbs/day 11,300 lbs/day 5.65 TPD YR. 2005 YR. 2005 FLOW SLUDGE (1) (GPD) (L BS/DAY) 400,600 567 12,800(4) 440 25,000 35 2,300(4) 79 (1) Sludge based on weight of dry soli0s (2) Average Suspended Solids Concentrate Utilized: Wastewater - 200 mg/l Scavenger Waste - 4,150 mg/l Assume 30 mg/l in effluent (3) All Shelter Island volumes are preliminary estimates (4) Volumes based on a implementation of a Septic Tank Management Plan (STMP) 1,121 1hs/c9ay 22,420 lbs/ciav 11.2 TPD HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. 4.3.1 Introduction The solids generated from a wastewater treatment plant repre- sent a substantial and important aspect to the total treatment process. Sludge treatment is necessary to permit disposal of ' these wastes in an environmentally sound manner. The treatment ' process to be selected depends on quality and characteristics of the sludge, method and cost of disposal, and cost of treat- ment. Treatment of sludge is performed to either reduce the volume, by removing water for final treatment and disposal, or converting ' the organic portion to a more stable and inert substance. The following are sludge treatment methods or processes which will be discussed in this section: ' Sludge thickening or dewatering will be required prior to any of the disposal methods in order to obtain a manageable ' material. Thickening involves the increase in solid concen- tration to a more dense sludge. Thickening methods include: gravity settling, flotation and centrifugation. Sludge de ' watering is designed to extract water from sludge such that 1 4.77 A. Treatment ' 1. Sludge Thickening 2. Sludge Dewatering 3. Digestion ' B. Disposal. 1. Composting ' 2. Land Application of Sludge 3. Incineration ' 4. Co -Disposal (Incineration or Composting) 5. Sanitary Landfill (Lined and Unlined) 6. Ocean Dumping ' Sludge thickening or dewatering will be required prior to any of the disposal methods in order to obtain a manageable ' material. Thickening involves the increase in solid concen- tration to a more dense sludge. Thickening methods include: gravity settling, flotation and centrifugation. Sludge de ' watering is designed to extract water from sludge such that 1 4.77 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 1 it assumes a non-fluid character. Sludge dewatering is ac- complished by a number of natural and mechanical means that incorporate the use of vacuum pressure, evaporation, centri- fugation and capillary action. Dewatering methods include: rotary vacuum filters, centrifuges, drying beds, filter presses, horizontal belt filters, rotating cylindrical devices and la- goons. The disposal of the sewage sludge produced at a treatment plant encompasses the second stage of sludge handling treat- ment processes described above, reduces the volume or changes the character of the sludge so that disposal can be facilitated. Cost is one of the primary considerations for sludge disposal methods. Thought should be given to the following items when determining the best alternative: ' 1. The cost of producing the form of sludge required for disposal. 2. Pre -transport storage cost. 3. Solids transportation to the disposal site. 4. Site storage costs. 5. Application costs. 6. Environmental protection and monitoring costs. 4.3.2 Sludge Thickening and Dewatering Conventional sedimentation processes in wastewater treat- ment achieve sludges with solids concentration of approximately ' 2 to 3 percent. Therefore, for both operational and economical 1 4.78 ' HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. ' reasons, thickening or dewatering must be implemented prior to ultimate sludge disposal. ' The existing sewage treatment plant utilizes sludge drying beds as a dewatering method. Secondary sludge from the final clarifier is pumped back to the Imhoff tanks, where it settles with the primary sludge. The sludge undergoes anaerobic diges- tion by the excessive retention time at the bottom of the Imhoff ' tank. The sludge is drawn off intermittently to the drying beds. A solids concentration of approximately 10 percent, obtained from ' the Imhoff tanks, increases to approximately 40 percent after ' sufficient time on the drying beds. Utilizing sludge drying beds is the most advantagous de- watering method for small facilities. Both low cost and mini- mal operation lends this method to be the most ideal alternative. 4.3.3 Anaerobic and Aerobic Digestion ' The major objectives of sludge digestion or stabilization are to reduce sludge volume, odors and the concentration of ' pathogenic organisms. Some form of sludge stabilization will ' be implemented unless the sludge is to be incinerated. An- aerobic and aerdbic digestion are the most popular stabilization ' methods used. A. Anaerobic Digestion ' This is a complex biochemical process in which the organic ' fraction of sludge is decomposed by anaerobic and facultative organisms. During the first phase of this two-phase process, 4.79 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. the organic portion is converted to volatile organic acids ' by the facultative, acid forming organisms. During the second ' phase, organisms convert the volatile organic acids to methane gas and carbon dioxide in the absence of free oxygen. The ' methane gas produced in this stage is the most valuable by- product of sewage treatment. Utilization of this gas can re- duce the cost of treatment by furnishing a portion of the energy ' needed for operation of the plant. The two principal uses of methane gas are heating and power production. ' B. Aerobic Digestion In this method as in anaerobic digestion, the organic frac- tion of the sludge is decomposed. A different type of organism undertakes this decomposition in the presence of oxygen. The organics are metabolized into carbon dioxide and water, and ' additional bacterial cells are formed. Dependent on the sewage treatment processes preceding sludge ' treatment, aerobic digestion may be more desirable than anaerobic ' digestion despite the loss of the methane gas by-product. 4.3.4 Composting ' Composting has been receiving increased attention as a viable sludge management alternative since the ban on ocean dumping. Briefly, the process consists of mixing the sludge ' with a bulking material, such as sawdust, wood chips, waste paper, leaves, etc. The sludge is then allowed to decompose ' for a specified period of time. This initial step is charac- terized as rapid decomposition where air is supplied by either ' 4.80 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. mechanical or forced draft systems. The reaction which takes place produces temperatures ranging from 140 degrees F to 160 ' degrees F. After this period of rapid digestion, the material is allowed to cure. The decomposition rate is slowed and the temperature of the mixture drops back to ambient with the pro- cess brought to completion. All remaining non-digestible debris present in the mixture is removed via screening. This process produces a product which is easily stored until needed, free of pathogenic organisms and odorless. How- ever, the primary problem has been lack of a market for the stable product. A market is required to produce revenue which ' would offset the high cost of operation and maintenance (par- ticularly the cost of a bulking agent and labor.) 4.3.5 _Lan_d Application of Sludge ' Sewage sludge contains many nutrients essential to plant ' life, such as the three basic plant nutrients, nitrogen, phos- phorus and potassium. The minor, but essential, nutrients in ' sludge are sulfur, calcium and iron. In addition to these ele- ments, boron, copper, magnesium, manganese and zinc are found ' in trace concentrations. Sometimes these minor elements are found in concentrations from industrial waste, which may be detrimental to plant growth. The sludge also benefits the soil ' by increasing the water holding capacity, improving the tilth and by retarding erosion. ' Sludge may be applied to crops in either the liquid or ' dried state. Common practice is to till dry sludge into the 4.81 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. soil while crops are being planted. Liquid sludge is applied ' during other times. When applying sludge to crop land, the mode of transportation, application procedure and rate of application must be considered. ' Transportation is accomplished by tank truck, barge, rail or pipeline. Transportation by tank truck is the least costly ' and most flexible method. Pipelines entail relatively high capital cost. ' Application rates depend on sludge composition, soil ' characteristics, climate, vegetation and cropping practices. The nitrogen component of sludge is the first factor that limits the rate of application, since adding excess nitrogen to soil involves the risk of polluting the groundwater with nitrates. ' High nitrate concentrations can be toxic to infants and live- stock. Therefore, it is essential that sludge be applied at a rate that would allow plants to uptake the nitrate before ' it leaches into the groundwater or runoff into surface waters. Pathogen control is also important when applying sludge to ' crop land. Some pathogens do survive the treatment process ' and remain in the soil for several months. Therefore, liquid sludge should nQt be applied to root crops or crops intended ' for human consumption in the raw form. Pastureland and farm- land used to grow forage crops can be used as land application sites. These present little problems in transmitting disease. ' Crops vary in their reaction to sludge enriched soils. Specific crops may be affected adversely by the trace elements 1 4.82 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. in the sludge. The crop may concentrate these certain trace ' elements, thereby, inhibiting future use of the harvested crop. The reaction of a specific crop to sludge application depends ' on soil type, p1l, moisture content, climate and the species of crop. ' Sludge application to agricultural land, if treated to ' reduce pathogen content, is of definite value as a source of nutrients. They are comparable to fertilizers and farmyard ' manure. It is a very popular utilization method because it is both cost-effective and simple. ' A monitoring and surveillance program for sludge disposal ' sites would be required. It is essential to monitor certain constituents in groundwater for the above mentioned reasons. ' 4.3.6 _ Sludge Incineration ' To reduce the weight and volume of sludge and produce an odorless and inert residue free of pathogenic organisms, com- bustion (incineration) is utilized for both treatment and final disposal. The basic elements of sludge incineration is part ' of an overall sludge treatment system which includes sludge thickening, sludge dewatering, a sludge feeding system, air pollution control devices, ash handling facilities and miscel- laneous related automatic controls. Due to the complexity of the method, monitoring of incoming sludge is essential to the ' proper operation of the process. 1 4.83 IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 11 ' Incineration is a two-step process involving drying and combustion. Drying should not be confused with preliminary ' dewatering; dewatering is usually accomplished by mechanical means, such as via a vacuum filter, centrifuge or filter press. The purposes of heat drying sludge are to raise the tempera-ture of the feed sludge to 212 degrees F; evaporate water from the sludge to practical limits and reduce the total volume. ' The purposes of incinerating sludge are to remove all moisture from the sludge by complete combustion; to destroy pathogenic organisms; and, produce an odorless ash. This ash would then ' be transported to a sanitary landfill for final disposal. Incineration of sludge is gaining popularity, especially at larger municipal and industrial wastewater treatment plants. In comparatively larger facilities, it has the advantages ' of economy, freedom from odor, independence of weather and ' great reduction in the volume and weight of the end product requiring disposal. However, it is not cost-effective for ' small sewage treatment plants. There must be enough sludge to necessitate the use of the costly equipment. ' Although incineration reauces the volume and removes of- fensive odors of the sludge, it also has the potential to be a contributor to air pollution. If operating procedures and in- ' coming sludge feed are not conducive to complete combustion, hydrocarbons and other objectionable products will be produced. 1 4.84 HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. ' Also, auxiliary fuel requirements will be needed to raise incinerator temperatures to the ignition point. Only if com- plete combustion is present will the process be self-sustaining. ' 4.3.7 Co -Disposal Co -disposal is the combined disposal of sludge and solid waste. Recent studies have shown that sanitary landfills are not an environmentally acceptable method of refuse disposal ' when liners, capping and leachate collection systems are not ' employed. The Town of Southold is presently evaluating alter- native methods of refuse disposal, since the existing landfill ' site will exhaust its available capacity by the year 1985. Over the next few years, the Town must choose an alternative method of refuse and sludge disposal in order to insure design, ' construction and operation of a new facility by 1985. Briefly, there are two primary methods that can be util- ized to dispose of sludge and refuse simultaneously. One is the system of incineration of solid waste and small amounts of sludge. This is somewhat similar to incineration of sludge ' as discussed in Section 4.3.6. The raw solid waste will have to be conditiongd through separation, shredding, grinding and slurry preparation so that waste can be easily mixed with sludge. This method can be used as an energy recovery system ' if the heat given off by incineration is utilized to generate ' steam which in turn can generate electricity. However, this method is cost intensive and must be designed on a large scale ' 4.85 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. operation. Southold presently generates approximately 95 tons per day (tpd) of refuse. Therefore, co -disposal incineration ' must be considered on a regional basis, incorporating surround- ing townships, if it is to be a vi -able alternative. This was ' examined in a recent study entitled "East End Solid Waste Manage- ment Study for the Towns of Southampton, Riverhead, Southold, East Hampton and Shelter Island" and found not economically ' feasible. Composting sludge with solid waste is a second means of ' co -disposal. Separated and shredded refuse can be utilized as the bulking material as described in Section 4.3.4. Composting is one of the oldest solid waste management practices available, yet its full use has not been realized. Unfortunately, the num- ber of failures of commercial composting plants in the United ' States, coupled with the lessening percentage of organic food waste in refuse, has significantly reduced the promise of this ' system as the sole method of municipal refuse disposal. The ' addition of sludge to the system may complicate operations. ' 4.3.8 Sanitary Landfill A sanitary,l.andfill can be used for the disposal of sludge, ' grease and grit before or after stabilization. A sanitary land- fill must be managed so that wastes are systematically deposited ' in designated areas, compacted in place with a tractor or roller, and covered with a 12 -inch layer of clean soil to control environ- mental impacts within set limits. When organic solids containing 1 4.86 IHOLZMACHER, McLENDON and MURRELL, P.C. 1 H2M CORP. ' free unbound water are placed in a landfill, decomposition, sur- face water contamination and leaching of sludge constituents to ' the groundwater must be considered. Decomposition may result in two problems. Odors may be produced if the required opera- tion of the facilities and soil cover is not maintained. Also, ' soil settlement might occur causing surface water ponding. Therefore, it is desirable to stabilize and dewater sludge prior to landfilling. The landfill must be managed so that surface topography would allow rainfall to run off the site rather than allow it to infiltrate into the soil. In additicia to surface topography, vegetation must be established quickly to prevent erosion. Further envrionmental measures, such as leachate lin- ing, leachate treatment and methane venting are required. En- vironmental regulatory agencies require long-term monitoring ' of landfill leachate. Stringent environmental impact control procedures have in- creased the cost of operating a landfill, though it is still generally less expensive than other disposal procedures. A second consideration would be the cost of dewatering require- ments which would increase the cost of this disposal alternative. ' 4.3.9 Ocean Dumping This has been an economical alternative for coastal cities ' for many years. Raw or digested sludge is pumped onto barges ' and carried to sea to be dumped far enough offshore to provide dilution and prevent any ill effects along the coast. ' 4.87 HOLZMACHER, MCLENOON and MURRELL, P.C. / H2M CORP. ' Due to recently promulgated USF.PA regulations which call for an end to ocean disposal by December 31, 1981, this alter- native will not be further evaluated. ' 4.3.10 Screenin%_of Alternative Sludge Mana ement Plans For the purposes of this report, a sludge treatment process ' has been defined as a combination of treatment and ultimate dis- posal methods for handling the sludge generated from the waste- water stream. The selection of an ultimate sludge disposal method is rela- tively independent of the wastewater treatment method. However, ' selection of a sludge treatment method is directly dependent on the upstream wastewater treatment methods. For example, if the chemical oxidation alternative is implemented, there would only ' be a need for dewatering and no need for stabilization. There- fore, each wastewater treatment alternative has already been matched up with a sludge treatment scheme in Sections 4.2 and 4.4. The selection of an ultimate disposal method is discussed ' later .in this section. ' Table 4.8 represents a matrix system that was prepared to display the various sludge management plans previously discussed. ' This matrix was developed to serve as a guide for comparative screening, since it provides a quantitative summary of judgments ' resulting from the screening of quantitative information. ' The detailed analyses which provided the substantiation for each of the judgments in the matrix is contained in the following sections. 1 4.88 TABLE 4.8 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT LEGEND: 1. NG - denotes that the alternative ULTIMATE SLUDGE DISPOSAL ALTERNATIVES the remaining alternatives due to the reason(s) cited in the report. SANITARY LAND Groundwater Pollution: Minimal -2, Moderate -4, Significant -8. 3. SCREENING FACTORS LANDFILL APPLICATION COMPOSTING INCINERATION 1. Groundwater 2 -Minimal NG 2 -Minimal 2 -Minimal Process Flexibility: Extensive -1, Pollution 7. Required Operator Skills: Good Skills -1, Highly Skilled -3. 8. Energy Intensive: Minimal -2, Moderate -4, Significant -8. 2. Environmental 4 -Moderate 4 -Moderate 4 -Moderate Impact 3. Monetary Cost 2 -Moderate 2 -Moderate 4 -Expensive 4. Process Reliability 2 -Conditional 2 -Conditional 1 -Reliable 5. Process Flexibility 3 -Limited 2 -Moderate 1 -Extensive 6. Required Operator 1 -Good Skills 1 -Good Skills 3 -Highly Skilled Skills 7. Energy Intensive 2 -Minimal 4 -Moderate 8 -Significant TOTAL 16 NG 17 23 LEGEND: 1. NG - denotes that the alternative will not be compared with the remaining alternatives due to the reason(s) cited in the report. 2. Groundwater Pollution: Minimal -2, Moderate -4, Significant -8. 3. Environmental Impact: Minimal -2, Moderate -4, Significant -8. 4. Monetary Costs: Minimal -1, Moderate -2, Significant -3, Expensive -4. 5. Process Reliability: Reliable -1, Conditional -2, Unreliable -3. 6. Process Flexibility: Extensive -1, Moderate -2, Limited -3. 7. Required Operator Skills: Good Skills -1, Highly Skilled -3. 8. Energy Intensive: Minimal -2, Moderate -4, Significant -8. 4.89 1 1 1 1 1 1 1 1 1 1 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. The following factors were evaluated for each sludge treat- ment alternative: 1. Groundwater Contamination 2. Environmental Impact 3. Monetary Cost 4. Process Reliability 5. Process Flexibility 6. Required Operator Skills 7. Energy Intensive Sludge Disposal Alternative 1 - Sanitary Landfill As mentioned in subsection 4.3.10, a major modification to the existing landfill area will be required to meet NYSDEC guide- lines, such as double lining, and methane and leachate collection. The screening factors were evaluated as follows: 1. Groundwater Contamination: Minimal - 2 2. Environmental Impact: Moderate - 4 3. Monetary Costs: Moderate - 2 4. Process Reliability: Conditional - 2 5. Process Flexibility: Limited - 3 6. Requirgd Operator Skills: Good Skills - 1 7. Energy Intensive: Minimal - 2 Total • . . . . . . . . . . • . . . . . 16 Sludge Disposal Alternative 2 - Land Application This sludge disposal alternative could not be implemented without having the probability of groundwater degradation from 4.90 ' HOLZMACHER, McLENDON MURRELL, P.C. and / H2M CORP. leachate generation. Hence, Sludge Alternative 2 has been as- signed a rating of NG and eliminated from future considerations. Sludge Disposal Alternative 3 -_Composting The concept of composting has been known for many years. ' However, composting sludge is still considered an Innovative and Alternative Technology. It is not known if a market is available for the final product, compost. Therefore, no revenues have been assumed in our cost analysis. ' follows: The screening factors were evaluated as ' 1. Groundwater Contamination: Minimal - 2 2. Environmental Impact: Moderate - 4 ' 3. Monetary Cost: Moderate - 2 4. Process Reliability: Conditional - 2 ' 5. Process Flexibility: Moderate - 2 ' 6. Required Operator Skills: Good Skills - 1 7. Energy Intensive: Moderate - 4 ' Total . . . . . . . . . . . . . . . . . 17 Sludge Disposal Alternative 4 - Incineration ' The factors were evaluated as follows: screening ' 1. Groundwater Contamination: Minimal - 2 2. Environmental Impact: Moderate - 4 ' 3. Monetary Cost: Expensive - 4 4. Process Reliability: Reliable - 1 ' 5. Process Flexibility: Extensive - 1 ' 6. Required Operator Skills: Highly Skilled - 3 7. Energy Intensive: Significant - 8 Total . . . . . . . . . . . . . . . . . 23 ' 4.91 IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' Relative to the other alternatives being evaluated, the monetary cost of incineration is extremely expensive and gives ' reason to rate this alternative as being eliminated from future consideration. 4.3.11 Summary Evaluation After discussing the various methods of sludge treatment and disposal, the following judgments were reached: 1. For the existing STP, the sludge drying bed method should be continued and expanded dependent on the extent of increased sewering. 2. A further examination will be conducted on the following sludge management plans: Sludge Management Plan A - Sanitary Landfill - with double liner, leachate collection system and a methane collection system. Sludge Management Plan B - Land Application of Sludge. Sludge Management Plan C - Composting. Sludge Management Plan D - Incineration - Multiple Hearth. A. Sanitary Landfill - Lined Using the design criteria of 2.1 cubic yards per day of dewatered sludge (40 percent solids after drying beds), it was calculated that approximately 1.3 acres of landfill would be required for a 20 year period. These calculations were based on the wide trench method of disposal with a ten (10) foot depth. Environmental agencies will require the installation of a double, polyvinyl chloride (PVC) liner. Equipment associated 4.92 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. with the liner is a leachate collection system which will pro- vide the necessary piping to pump out any leachate that collects ' above the lining. In addition, the installation and operation of a methane ' gas collection system may also be required. A groundwater monitoring system will be required by en- vironmental agencies to determine if any leaks in the liner ' occur. B. Land Application ' Due to the agricultural nature of a significant portion of Southold, the land application of sludge could be publicly ' accepted because of the sludge's nutritional value. However, ' studies have shown that full utilization of the nutrients is not possible, thereby allowing a portion of nutrients to be ' leached. As previously discussed throughout this report, any alternative which will contribute to the degradation of the ' groundwater quality should be disregarded from further analysis. C. Composting There are two different methods of composting sludge. ' Both the static pile and windrow methods of composting, sta- bilize the sludge to a final product of humus -like material, ' free of odors and useful as a soil conditioner. ' The static pile method employes a four -step process where the sludge is mixed with a bulking material and formed into ' aerated piles. Air is then drawn through the pile with the use of a blower to provide oxygen to thermophilic microorganisms 1 4.93 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. C ' that facilitate decomposition. After twenty-one days, the sludge and bulking material are spread out in a 12 -inch layer to dry. Once dry, the sludge is separated from the bulking material ' and the humus -like sludge undergoes further curing while it is stored in piles. This is to assure that no offensive odors ' remain and that stabilization is complete. The windrow method also employes microbial degradation of ' sludge by aerobic metabolism in piles or windrows. The piles are turned periodically to provide for the microoganisms to ' carry out the stabilization process and to carry off the excess ' heat that is generated by the process. An examination of the windrow method of composting suggests ' that this process would be the most appropriate for the Greenport/ Southold sludge problem. The main difference between composting ' methods is the manner in which air is supplied to the composting ' pile. The windrow method induces air to the system by periodi- cally turning over the pile. Advantages of this process are its ' simple operation and low energy requirements. Composting provides a slow method of releasing some of the nitrogen within the sludge by converting it to nitrogen gas. ' The finished compost material can be used as a fertilizer supple- ment where nitrogen can be utilized through plant uptake. A mar- ket for compost should be readily available with both agricul- tural and horticultural activities in the immediate area. How- ever, acceptance of compost material by the public may be diffi- ' cult. 4.94 INOLZMACHER, MQLENDON and MURRELL, P.C. / H2M CORP. ' Composting of sludges is an environmentally sound treat- ment method for the study area as the sludge generated is relatively free of toxic materials. This method takes a rela- tively small area and does not have a significant potential of polluting groundwater. Although the composted sludge is ' rather low in nutrient value, it greatly improves the physical properties of soils by increasing water content and retention, ' increasing soil aeration, improving permeability and reducing crusting. For agricultural applications, it is good practice ' to use compost with inorganic fertilizer to sustain optimal ' crop yields. D. Incineration ' The multiple hearth furnace is the most commonly used sludge incineration process. This method of disposal will reduce sludge volume to approximately one-tenth of the volume ' of sludge at 20 percent solids. The residue from incineration will still require disposal, which is most commonly accomplished ' by landfilling. The Federal Air Quality Act of 1967, as well as State legis- lation, has imposed strict limits on sludge disposal by inciner- ation. Technological advances in incineration process controls would not significantly degrade air quality in the area. How- ever, to construct and operate an incinerator designed to meet emission standards would be costly in relation to other environ- mentally sound alternatives. 1 4.95 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 4.4 Scavenger Waste ' 4.4.1 Introduction ' Scavenger wastes (septic wastes) are the wastes collected from malfunctioning or fully utilized cesspools and septic ' tanks of homes, restaurants and commercial establishments. The Town of Southold currently operates a scavenger waste ' disposal site at the Town sanitary landfill. The wastes are ' brought to the landfill site and are dumped into open leach- ing basins. Although this method of disposal is the most in- expensive, there are many potential environmental problems associated with it. The New York State Department of Environ- mental Conservation has issued a State Pollution Discharge ' Elimination System (SPDES) permit which incorporates a com- pliance schedule that requires cessation of the present dis- posal practice. Part of the compliance schedule requires the Town to com- plete the 201 Wastewater Facilities Report, and within examine ' alternative scavenger waste treatment and disposal methods. The ultimate requirement of the compliance schedule is to close ' the septic waste disposal site upon construction of the alter- native treatment and disposal facility. ' This section will evaluate the current method of disposal, as well as evaluate alternative means of treatment and disposal. In addition, regional alternatives for Southold and Shelter ' Island will be evaluated. The investigations in this section have been coordinated and are consistent with the Nassau -Suffolk ' 208 Study recommendations. 1 4.96 ' HOLIMACHER. McLENDON and MURRELL, P.C. / H2M CORP. 4.4.2 Existing Disposal Methods ' There is one (1) scavenger waste disposal site currently ' in operation in the study area. The existing Southold septic waste disposal site is part of the Southold Solid Waste Dis- posal Facility (sanitary landfill) located in the community of Cutchogue on North Road (County Road 27) between Cox Lane ' and Depot Lane. The facility is situated in a rural indus- trially zoned area. The location is shown on Figure 4.10. Scavenger waste is discharged into either of two (2) un- covered, unlined, 100 feet by 75 feet leaching lagoons located in the northwest corner of the Southold landfill site. A ' third lagoon was previously utilized, but excessive usage re- sulting in soil pore cloggage has necessitated the abandonment of this lagoon. The lagoon was covered with excavated earth, ' mainly fine sand and gravel, in accordance with the latest New York State Solid Waste Management Regulations. Topographic photographs have shown that the bottom of the ' lagoons are at an elevation of 29 feet. The groundwater table in the area is approximately 3 feet above sea level. Therefore, ' there is a soil buffer zone of 26 feet between the water table and the point of surface discharge. ' This buffer provides partial cleansing of the wastes by removing many of the solids. However, the degree of treatment is not sufficient to prevent contamination of the groundwater. ' The percolate from the lagoons attributes to the degradation of the groundwater flowing beneath the site. ' 4.97 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 TOWN SANITAI AN VMS LOCATION OF EXISTING SCAVENGER WASTE DISPOSAL SITE TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY I HOLZMACHER, McLENDON & MURRELL, P.C. /H 2 M C.ORP. MELVILLE, N.Y. I CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS FARMINGDALE, N.V. NEWTON. N.J. ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' 4.4.3 Quality of Scavenger Waste A literature search was performed in order to determine the ' physical and chemical characteristics of scavenger waste based ' on previous studies and/or projects. Since the work of numerous authors and investigators was reviewed, only a summary of the ' literature search is presented in this report. Scavenger waste (septic tank/cesspool waste): (a) is ' usually an anaerobic slurry containing large quantities of grit ' and grease; (b) has poor settling and dewatering characteristics; (c) has a high solids and organic content; (d) has an offensive ' odor; and (e) may contain an accumulation of heavy metals and other chemicals if it is industrial in nature. In Figures 4.11 and 4.12, typical cesspools and septic tanks are depicted. ' The characteristics of scavenger waste are highly variable and usually depend on the origin of the waste and the frequency ' the cesspool or septic tank is pumped. For example, waste from laundromats, restaurants and commercial on-site sanitary systems will all differ in characteristics. ' Restaurant waste will generally be raw and high in grease and oil concentrations. On the other hand, residential waste, ' especially that which has not been pumped from a cesspool has a higher solid content and will be a fairly digested slurry. Since the physical and chemical characteristics of scavenger ' waste is highly variable, especially from truck load to truck load, a statistical analysis for the frequency of occurrence ' of the design parameter constituents should be performed. This information could then be employed in the basis of design. 4.99 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 FIGURE 4.11 I' MIN. 2' MAX. CONCRETE COVER q CONCRETE CHIMNEY -y- I5' MAX. I INLET � ---- 20° 1 OVERFLOW TO 2^d POOL 'F❑'_ 0 1= LEACHING SECTIONS SOLIDS L - SCAVENGER WASTE -SOLIDS+ 2' MIN. UNLEACHED WATER. GROUND WATER TYPICAL CESSPOOL TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY Y. HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARM"IE. LE, FARMMJOpAIE. N Y CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS NEWT EAD.,N V. NEWTON, N, J 4.100 1 1 1 1 1 1 1 1 1 1 1 1 I INLET— FINISHED GRADE I 2' MAX. I' MIN. %0%,mv b1VVVfl "M.0I V. TYPICAL SEPTIC TANK FIGURE 4.12 —�^ OUTLET TO I LEACHING FIELD TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY HOLZMACHER, MCLENDON a MURRELL, P.C. / H2M CORP. FARMW4 D N.V. FARMMVGOALE, N Y CONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIENTISTS NEWTFOVEREAO. N Y NEWTON. N J 4.101 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. Typical septage characteristics, as reported by the United States Environmental Protection Agency (USEPA) in their Tech- nology Transfer Seminar publication entitled, "Alternatives for Small Wastewater Treatment Systems - On -Site Disposal/Septage ' Treatment and Disposal", are shown in Table 4.9. Further, a report prepared by Eckenfelder & O'Conner in 1960 ' for the Town of Oyster Bay, reported the data presented in Table ' 4.10 for scavenger waste characteristics. The same study in- cluded the frequency distribution shown in Table 4.11. ' The concentration of BOD -5 and SS and pH values of scaven- ger wastes received for treatment at the Bay Park Sewage Treat- ment Plant in Nassau County are summarized in Table 4.12. It is demonstraLed in Tables 4.9 through 4.12, the charac- teristic variability scavenger waste can have. This fact is ' consistent with the findings of numerous other investigators. Lastly, the alternatives addressed in this section are con- sistent with those recommended for the most part in the litera- ture. These include chemical oxidation, anaerobic/aerobic ' treatment, and aerobic treatment either by rotating biological tdiscs or activated sludge preceded by chemical precipitation. Due to the similarities of the Townships of Riverhead and ' Southampton with Southold, the results of scavenger waste analyses ' in Riverhead and Southampton will be used as design criteria for selection of alternative treatment processes. ' Grab samples were taken from scavenger waste trucks arriv- ing at three facilities in Riverhead and Southampton, on various 4.102 TABLE GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT ' TYPICAL SEPTAGE (SCAVENGER WASTE) CHARACTERISTICS USEPA MEAN MINIMUM MAXIMUM PARAMETER CONCENTRATION REPORTED REPORTED VARIABILITY (1) ' Total Solids 40,000.0 1,132.0 130,475.0 115 Total VS 26,000.0 4,500.0 71,402.0 16 ' Total SS 15,000.0 310.0 93,378.0 301 VSS 18,100.0 3,660.0 51,500.0 14 ' BOD -5 5,000.0 440.0 78,600.0 179 COD 45,000.0 500.0 703,000.0 469 TOC 15,000.0 316.0 96,000.0 73 ' TKN 600.0 66.0 1,900.0 29 NH3-(N) 150.0 6.0 380.0 63 ' NO2- (N) 0.7 0.1 1.3 13 NO3-(N) 3.2 0.1 11.0 110 ' Total P 50.0 20.0 760.0 38 PO4-(P) 64.0 10.0 170.0 17 Alkalinity (CaCO3) 1,020.0 522.0 4,190.0 8 ' Grease 9,561.0 604.0 23,368.0 39 pH (units) 6 to 9.0 1.5 12.6 8 ' 2 LAS 150.0 110.0 200.0 (1) Approximate ratio of maximum value to minimum value. All concentrations measured in mg/1, unless otherwise noted. 1 '4.103 TABLE 4.10 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVE EVALUATION & ENVIRONMENTAL ASSESSMENT 10-110RT ' SCAVENGER WASTES* RAW WASTE VARIATIONS ' CONSTITUENTS BOD -5 day (mg/1) 260 to 3,000 ' Suspended Solids (mg/1) 400 to 36,800 ' pH 2.6 to 11.9 ' TABLE 4..11 WASTE CHARACTERISTICS AND VARIATIONS* ' CONCENTRATION - mq/1 % FREQUENCY TRUCK SAMPLES 10% 50% 900 ' BOD 350 900 2,200 Suspended Solids 540 3,800 22,000 COMPOSITE SAMPLES BOD (Total) 500 1,700 5,500 BOD (soluble) 150 480 1,450 Suspended Solids 1,400 5,600 23,000 C *Biological Treatment. of Septic Wastes, Town of Oyster Bay, N.Y., Eckenfelder & O'Connor, Consultants (for Tables IV -2 & IV -3). TABLE 4.12 SCAVENGER WASTES RECEIVED AT BAY PARK SEWAGE TREATMENT PLANT* MINIMUM AVERAGE MAXIMUM BOD - mg/l 440 1,020 1,460 Suspended Solids - mg/l 550 4,500 35,000 pH 1.5 7.2 12.6 *Reported in "Report Upon Scavenger Wastes, Town of Brookhaven" John J. Baffa, Consulting Engineers (for Table IV -4). 4.104 iHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 1 dates in December of 1978 and January of 1979. Analyses were ' performed on these samples for various parameters. The results ' of the analyses are shown in Table 4.13. Similar to the literature search, these analyses show a ' wide disparity between samples. In order to design a facility to treat all incoming waste, the design concentration of the ' waste must be estimated based on the above data. A frequency ' distribution analysis of the parameters will be used as the design criteria parameter concentration, as indicated in sub- section 4.4.5 - Design Considerations. ' 4.4.4 Present and Future Scavenger Waste Volumes The precise determination of incoming scavenger waste quan- tities at the Southold landfill is difficult due to the absence of accurate records. Suffolk County Department of Health Services requires the ' Town of Southold to record the volumes and origin of all scavenger waste entering the landfill site. However, due to operational ' procedures, the accuracy of the records is questionable. There- fore, a survey was conducted to obtain a more accurate record of incoming wastes. As discussed in Volume I of this report, ' an average daily flow at 3,100 gallons was estimated from a survey conducted in April of 1979, with 68 percent being resi- dential, 24 percent commercial and 8 percent generated from restaurants. Typically, residential waste is collected from ' system failures, while commercial and restaurant wastes are ' collected on a periodic maintenance basis. ' 4.105 TABLE 4.13 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT SCAVENGER WASTE ANALYSES (ma/1) LOCATION DATE BOD SS TS COD P O&G TKN NO3 NH3 TVS North Sea 12-5-78 865 204 767 1,000 6.2 536 44.8 41.0 28.0 385 12-13-78 2,920 4,430 5,960 7,300 5.9 1.26% 123.0 41.0 5.6 3,750 12-21-78 3,670 4,980 4,210 6,690 6.6 2,560 87.4 41.0 < 1.0 3,250 1-3-79 2,070 1,810 2,250 4,660 7.4 635 224.0 41.0 89.6 1,360 1-17-79 2,010 690 1,400 3,020 7.5 497 42.0 <1.0 23.8 814 1-26-79 1,830 3,450 4,000 1,400 6.9 420 88.0 41.0 11.0 1,688 2-1-79 280 101 400 470 7.3 54 95.0 41.0 20.0 192 Total 13,645 15,665 18,987 24,540 47.8 17,302 704 47.0 179 11,439 Average 1,949 2,238 2,712 3,506 6.83 2,472 101 41.0 26 1,634 Riverhead 12-5-78 1.49% 1.87% 1.97% 3.72% '7.1 7,360 448 41.0 11.2 1.5% 12-13-78 5,550 2,820 3,910 5,380 6.4 7,900 112 41.0 33.6 2,460 12-29-78 2,250 3,120 5,250 4,290 6.7 1,610 381 41.0 101 4,210 1-3-79 5,390 3,220 3,410 6,730 7.2 2,480 112 41.0 11.2 2,580 1-8-79 1,920 1,720 1,590 3.30% 6.8 1.07% 448 41.0 154 1,180 1-17-79 3,170 2,410 4,910 1.41% 6.9 1,300 109 41.0 79.8 2,980 1-22-79 1.27% 1.65% 9,000 1.93% 6.7 7,570 451 41.0 78.4 5,310 1-26-79 1.10% 1.6% 2.1% 1.81% 5.4 3,270 493 Q.0 65.0 1.55% 2-1-79 2,550 1,750 1,870 1.15% 6.0 3,770 305 Q.0 45.0 1,548 Total 59,430 66,240 70,640 149,600 59.2 45,960 2,859 <3.0 579.2 50,768 Averaae 6,603 7,360 7,849 16,622 6.58 5,107 318 <1.0 64.4 5,641 West Hampton 12-13-78 1.02% 1,800 1.42% 2.19% 6.4 1.20% 762.0 41.0 33.6 9,680 12-21-78 1.22% 1.84% 1.80% 2.62% 6.0 2,750 414 <1.0 44.8 1.22% 12-29-78 2,530 3,970 5,230 4,060 7.0 3,220 482 <1.0 123 3,770 1-3-79 1.09% 1.12% 9,130 1.59% 7.1 1.4% 963 <1.0 638 5,130 1-8-79 4,010 8,370 4,680 5,500 8.9 1,710 616 41.0 112 3,430 1-17-79 6,660 2,420 5,020 7,290 8.5 698 1,580 <1.0 1150 2,370 1-22-79 1.82% 8,290 1.20% 1.77% 7.1 5,290 1,190 < .0 196 6,810 1-26-79 6,750 2,610 5,000 1.85% 9.0 4,500 784 <1.0 468 2,800 2-1-79 6,900 8,140 1.27% 1.47% 7.4 3,810 750 <1.0 112 8,760 Total 78,350 65,200 85,960 131,750 67.4 47,978 7,541 :9.0 2877 54,950 Average 8,706 7,244 9,551 14,639 7,49 5,331 838 X1.0 320 6,106 4.106 HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. LJ ' A second survey was conducted in September of 1979 and revealed a larger volume of scavenger waste being accepted at ' the landfill. Figure 4.13 depicts the breakdown of the survey. An average daily flow was calculated as 6,390 gallons, with ' 66 percent residential, 11 percent commercial and 23 percent ' from restaurants. The increase between April and September could be due to the seasonal population fluctuation and restau- L 11 L rant activity. In determining the yearly volumes of scavenger waste dis- posed of at the leaching lagoons, the combined data of conver- sations with Town personnel, two surveys conducted on the dis- posal of scavenger wastes at Southold and the actual monthly averages of scavenger waste disposal at the Town of Riverhead disposal site provided sufficient data to obtain monthly varia- tions and average volumes. Approximate scavenger waste volumes were estimated by interpolating the two surveys onto the monthly variations as recorded by the Riverhead facility. The peak flow usually occurs in the month of August with a minimum flow occur- ring in December and January. It was therefore estimated that the present average daily volumes on a yearly basis would be approximately 4,200 gpd or 1,533,000 gpy. Future scavenger waste volumes must be estimated before a treatment facility can be adequately designed. Factors to be used to estimate these volumes include population, number of septic systems, frequency of pumping and the average volume pumped from the systems. 4.107 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 FIGURE 4.13 LEGEN O - COMMERCIAL =- RESIDENTIAL 20,000 ® - RESTAURANT 15,000 Z 910,000 5,000 0 9/10 9/11 9/12 9/13 9/14 9/15 9/16 9/17 9/18 9/19 9/20 9/21 9/22 9/23 9/24 M T W T F S S M T W T F S S M DAY NOTE: SURVEY WAS CONDUCTED IN SEPTEMBER 1979 SCAVENGER WASTE SURVEY TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILHOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMIN DALE. , FARMINGDAIE, N V CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS NEWT EAD, N Y NEWTON N J 4.108 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' If a septic tank management plan is to be implemented, ' all residents will be required to pump their septic systems every few years. We shall assume that the pumping will occur ' every three (3) years. ' As with all other alternatives, a design year of 2005 will shall be the basis of the analysis. The following calculations ' depict the procedures used to obtain future residential scaven- ger waste flow: ' Total Town Population in 2005 = 38,056 Sewered Population in 2005 = - 5,700 I Population Using On -Site Systems = 32,356 ' Assume 3.0 Capita Per Dwelling Unit(') Therefore, 32,356 CAP _ ' 3 10,785 D.U. .0 CAP/D.U. - = 10,785 Septic System ' Assume 1,500 Gallons Pumped Every 3 Years 10,785 x 1,500 gallons x .33 = 5,338,600 gpy ' The most appropriate method of projecting commercial flow is to correlate the present flow with the present land use ' acreage. The future flow can therefore be derived from the ' projected land use, as described in Section 3.1.3.1 of the Engi- neering and Data Report. The calculations are depicted below. ' Present Commercial Land Use(2) 202 Acres Future Commercial Land Use (2) 447 Acres ' (1) NSRPB - 208 Study (2) Excludes acreage located within existing sewer district t 1 4.109 HOLZMACHER, McLENDON and MURRELL, P.C. f H2M CORP. ' Acreage Increase 121 Percent Present Annual Flow 505,900 Gallons ' Future Annual Flow 505,900 x 2.21 = 1,118,000 Gallons This method of projecting the commercial flow will not be ' affected by a septic tank management plan, due to the fact that ' most commercial establishments already pump their systems rather frequently. The total future flow is then projected as 6,456,600 gallons per year for 2005. 1 4.4.5 Design Considerations ' The criteria used to aid in the evaluation of alternatives is as follows: ' 1. The 50 percent frequency of occurrence and 90 percent ' frequency of occurrence is as follows: (in mg/1) 50 Percent 90 Percent ' BOD 4,770 13,970 NH3-N 105 341 TKN 345 1,090 ' Suspended Solids 4,150 13,820 Total Solids 5,500 16,500 ' Total Volatile Solids 3,600 11,680 Figures 4.14 through 4.19, depicting the frequency of occur- rence distribution, were utilized to obtain the above parameters. ' The 50 percent occurrence concentrations will be used for the design of the alternatives. The two major criteria are suspended '4.110 FIGURE 4.14 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 FIGURE 4.15 40 30 20( 0 X) )o • • -95% 443 MG/1- • -90% 341MG/L • • O OU -4 VV% Un,& FREQUENCY OF OCCURRENCE FREQUENCY OF OCCURRENCE AMMONIA NH3-N TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE 'N.y- HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMWIGOALE, N Y CONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIENTISTS NEWTRVERHE AD, N Y ON N J 4.112 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 FREQUENCY OF OCCURRENCE FREQUENCY OF OCCURRENCE TKN 1410 MG/L 'L FIGURE 4.16 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE, N.Y. HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMINGDALE, N Y CONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIENTISTS NEWT EAO. N V NEWTON, N J 4.113 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 FIGURE 4,17 20JDOO- 18p� .300 15.820 12,000- - ------ - Z O 10,000 ---- ------ z 0 L) 6.000 ------- 4,000 2,00() 10% 550 10% 50% 90% 5% FREQUENCY OF OCCURRENCE FREQUENCY OF OCCURRENCE TOTAL SUSPENDED SOL -IDS TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE N.Y. HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMINGDALE N Y RIVERHEAD. N Y CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS NEWTON. N J 4.114 k IT • • • 20JDOO- 18p� .300 15.820 12,000- - ------ - Z O 10,000 ---- ------ z 0 L) 6.000 ------- 4,000 2,00() 10% 550 10% 50% 90% 5% FREQUENCY OF OCCURRENCE FREQUENCY OF OCCURRENCE TOTAL SUSPENDED SOL -IDS TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE N.Y. HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMINGDALE N Y RIVERHEAD. N Y CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS NEWTON. N J 4.114 FIGURE 4.18 22.000 -- -------------------- 20,000 16,000 9O%16,5(Xl M.lI- 14,000. • - J L7 • Z12,0()(1 ___.. .. -.. ._ _. _.. _--- -. •.____. __.. _.. .. __ __ _. ... _. ___. Q Q cr zi0,00(I _ W O • • V 4000 — - - 50%5,500 MG/L • • • 4,000- 10% .000-10% 1,400 MG/L O— — -- —._._------ --- -- 10% 50% % 95% FREQUENCY OF OCCURRENCE FREQUENCY OF OCCURRENCE TOTAL SOLIDS ' TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE, N.Y. HOLZMACHER, MCLENDON & MURRELL, P.C. / H2M CORP. FANMINGIALE NY CONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIENTISTS RlvErNEWTTON. ON NN. J v 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 FIGURE 4.19 FREQUENCY OF OCCURRENCE FREQUENCY OF OCCURRENCE TOTAL VOLATILE SOLIDS 20 TOWN OF SOUTHOLD - INC. VILLAGE 0 F GREENPORt WASTEWATER FACILITIES STUDY HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMIN ID, N.Y. ARMNVGALE. N. V CONSULTING ENGINEERS, PLANNERS and ENVIRONMENTAL SCIENTISTS NEWT EAD, N V NEWTON. N. J 4.116 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' solids and BOD -5 which will be approximated at 4,150 mg/l and 4,770 mg/l, respectively. ' 2. Flow equalization is recommended. With proper mixing and blending, a homogeneous mixture can be obtained. Thus, ' this results in a composite sample with the parameter concen- trations approaching the 50 percent frequency of occurrence. ' For Alternatives SW -3 through SW -6, (see Section 4.4.6, Treat- ' ment Alternatives), the flow equalization tank will also be used as a storage tank allowing the septic waste to be bled ' into the raw wastewater in proportion to the wastewater flow. 3. Plant Flow - Design Year 2005 Town of Southold ' a. With a STMP 17,700 gpd (7/Day/Week) Town of Shelter Island ' a. With a STMP 2,300 gpd (7/Day/Week) Combined Flows ' 7 Day/Week 5 Da Week ' a. With a STMP 20,000 gpd 28,000 gpd STMP = Septic Tank Management Plan ' 4.4.6 Treatment Alternatives ' Scavenger waste disposal is a problem that is not common only to Southold. All of the eastern towns in Suffolk County ' are currently using leaching lagoons, and must find an alternate means of disposal. The Towns of Riverhead and Southampton have ' joined to find a common solution to their problem. We will examine alternatives on a sub -regional basis, where Southold 4.117 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. will solve their own scavenger waste problem and also can a ' regional basis where Southold and Shelter Island will join together to solve this problem. A cost analysis will be per- formed to determine the most cost-effective alternative to ' collect and treat scavenger waste. In this evaluation, ten main flow stream treatment alter- natives will be investigated. Each alternative will be evalu- ated on a regional and sub -regional basis. "A" will represent alternatives examined on a sub -regional basis, treating only ' Southold waste. "B" will represent alternatives examined on a regional basis, treating a combined flow from Southold and ' Shelter Island. ' The alternatives are: ALTERNATIVE SW -1 - - No Action Continue Lagoon Disposal ' ALTERNATIVE SW -2 - Transporting to Other Treatment Systems ALTERNATIVES SW -3-6 - Combined Treatment at the Existing ' Greenport STP ALTERNATIVE SW -3 - Activated Sludge - Combined Flow ' ALTERNATIVE SW -4 - RBD & Effluent Polishing Combined Flow ALTERNATIVE SW -5 - RBD -Activated Sludge Combined Flow ' ALTERNATIVE SW -6 - Primary -RBD Treatment Prior to Combined Flow ' ALTERNATIVE SW -7 - Aerobic Treatment - RBD ALTERNATIVE SW -8 - Aerobic -Anaerobic Treatment ALTERNATIVE SW -9 - Chlorine Oxidation-Purifax System I ALTERNATIVE SW -10 - Natural System - Marsh -Meadow -Pond '4.118 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' In evaluating scavenger waste treatment alternatives, we ' shall assume the site to be located at or in close proximity to the existing Greenport Sewage Treatment Plant (STP). As tabu ' lated below, significant advantages can be obtained by locating the scavenger waste facility on the same site as the existing ' STP: 1. Reduction of capital construction costs. ' 2. Reduction of operating costs. 1 3. Inexpensive acquisition of land. 4. Minimize environmental impact. Some of the alternatives call for the utilization of exist- ing treatment processes through the combined treatment of sludges ' and further treatment of filtrate and supernatant. Utilizing ' existing processes eliminates the need to construct additional processes, in turn reducing the capital construction costs. ' In line with the above reasoning, operating costs will also be reduced. Items such as labor and material costs can be opti- mized by utilizing personnel more effectively. ' The Inc. Village of Greenport presently owns sufficient land adjacent to the existing plant to accommodate additional ' facilities. Agreements between the Towns of Southold and/or Shelter Island and the Inc. Village of Greenport can be arranged to decide on management and operation and maintenance of the I facilities and property. 1 4.119 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. I ' By coupling the facilities, esthetically displeasing con- ditions can be concentrated to one area rather than two or more locations throughout the Town. Adverse environmental impacts, such as odors and excessive noise would also be buffered due to the remoteness of the existing location. A. ALTERNATIVE SW -1 - (No Action - Continue Lagoon Disposal) If No Action is taken to implement an alternative treatment and disposal system of scavenger waste, New York State Depart- ment of Environmental Conservation (NYSDEC) will most likely take legal action against the Town. Monetary fines and im- prisonment of Town Officials could be the results of discharg- ing without a SPDES permit. Therefore, Alternative SW -1 has been found to be a non-viable alternative and will not be fur- ther investigated in our analysis. The present method of disposal has unacceptable environ- mental impact in terms of being a potential public health ' hazard and has a negative impact on the groundwater quality Iwithin the Town. This impact will be further discussed in Section 4.4.10 - Environmental Impact• ' B. Preliminary Treatment Facility Common to all of the alternatives, except Alternative SW -1, is preliminary treatment of scavenger waste. This head ' end facility would be required to ease the operation of a plant by simplifying the discharge of scavenger wastes from the ' haulers and removing grit and large objects from the waste stream to prevent excessive wear on equipment. 4.120 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. The head end facility consists of a receiving chamber, ' influent pumps, mechanical screens, cyclone degritter and classifier, and a combination equalization/blending tank. An odor control system is also provided in this facility. ' A flow schematic is depicted on Figure 4.20. C. ALTERNATIVE SW -2 - Transport to Another Treatment System ' Alternative SW -2 includes the collection of septic wastes at a central point within the Town and then transportation to another treatment facility. Suffolk County has constructed a scavenger waste treatment facility, which is scheduled to go on-line during 1981 at the Bergen Point Sewage Treatment Plant ' located in West Babylon. In addition, the Towns of Riverhead and Southampton are planning to construct a scavenger waste ' treatment facility which is to be operational in late 1982. ' Both of these facilities will be considered in this evaluation. Components to be examined are: loading facilities construction; ' transportation vehicles acquisition; manpower; fuel; maintenance; and a tipping fee that will be instituted by the accepting ' facility. ' Selection of Alternative SW -2 requires implementation of an interim program of transporting scavenger waste to the Ber- gen Point facility until the completion of the Riverhead -South- ampton facility. At that time, the cost-effective analysis should be revised to re -confirm that transporting to and treat- ing at Riverhead would be cheaper than transporting to West Babylon for treatment. In order for Bergen Point to remain ' 4.121 TRUCKS DISCHARGE SCAVENGER WASTE ODOR CONTROL. RECEIVING CYCLONE CHAMBER DEGRITTER & SCREENS ODOR CONTROL EQUALIZATION TANK PLUS BLENDING FIGURE 4.20 TO TREATMENT UNITS Q8 HAULED TO ANOTHER TREATMENT SYSTE Z -WASHED GRIT TO LANDFILL SCREENINGS TO LANDFILL FLOW SCHEMATIC HEAD END FACILITIES - ALTERNATIVES SW -2 TO SW -10 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE. N.V. HOLZMACHER, McLENDON & MURRELL, P.C. I H2M CORP. EARMING.ALE Nv CONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIEN rISTS NFW1 EAo N v NFW17"ON N I 4.122 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' cost-effective, a significant tipping fee would have to be imposed by Riverhead and Southampton. We anticipate that ' the tipping fee at Bergen Point will be the same or slightly less than the fee to be charged at the proposed Riverhead plant. Consequently, the long-term solution under Alter- native SW -2 would be teatment at the proposed Riverhead - Southampton facility. ' If one of the other alternatives is selected, NYSDEC has indicated that the Town(s) may continue the present dis- charge methods until construction is complete. However, if in the interim period, governmental agencies require the immediate cessation of lagoon disposal, Alternative SW -2 ' on a short-term basis should be implemented. D. ALTERNATIVES SW -3-6 - Combined Treatment at the ' Existing STP Since the Inc. Village of Greenport presently operates a STP, it may be economical to modify the plant to accommo- date the additional flow from scavenger wastes. There are some existing treatment plants on Long Island currently using ' this dual system to handle a combined flow of sewage and sep- tic waste. As previously stated in Section 2.6, the existing sewage ' treatment plant is only marginally meeting the discharge limi- tations set forth in the SPDES permit. It is anticipated that ' if a concentrated waste is added to the influent, the existing 1 4.123 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. treatment processes will not provide the treatment necessary to maintain compliance with the permit. We have estimated that a combined flow of sewage and septic wastes would provide average influent concentrations of 418 mg/l ' of BOD -5 and 388 mg/l of Suspended Solids (SS), as shown in Table 4.14. This would not be adequately treated by the aerated ' lagoon system as it now exists. Upgrading or modifying the ' existing system to accommodate this highly concentrated waste- water would be required. ' Alternatives SW -3 through SW -6 are various methods whereby the existing treatment facility could be upgraded or modified. D.1 ALTERNATIVE SW -3 - Activated Sludge (Combined Flow) ' After preliminary treatment, the septic waste is bled into the raw wastewater flow stream. A complete mix process modi- fication of activated sludge is established by having the in- fluent settled sewage and return sludge flow introduced at ' several points into the aeration tank from a central channel. ' The mixed liquor is aerated as it passes from the central channel to effluent channels at both sides of the aeration tank. This ' process provides resistance to shock loads that may occur from an excessive hydraulic and/or organic loading of scavenger wastes. A flow schematic of this alternative is shown on Figure ' 4.21. One operational problem that might plague this system is ' that of obnoxious odors, a primary characteristic of scavenger 4.124 *See Section 4.4.5, we have assumed a concentration equal to the 50% frequency occurrence. TABLE 4.14 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT ADDITION OF SCAVENGER WASTES TO EXISTING GREENPORT STP GREENPORT SOUTHOLD SHELTER ISLAND SEWERED AREAS SCAVENGER WASTE SCAVENGER WASTE TOTAL Flow Year 2005 (mgd) 0.40 .0177 .0023 .42 BOD -5 Conc. (mg/1) 200 4770* 4770* 418 Loading Ln (#/Day) 667 704 92 1463 S.S. Conc. (mg/1) 200 4150* 4150* 388 Loading (#/Day) 667 613 80 1360 *See Section 4.4.5, we have assumed a concentration equal to the 50% frequency occurrence. SCAVENGER WASTE FROM HEAD END FACILITY RAW WASTE WAT E tea—T T 1 PRIMARY I AERATION FINAL ` SETTLING SETTLING TANK I TANKS TANK I tt • aaa�a'iw� I PS RAS T • • IWAS 's VACUUM / _ ANAEROBIC _ FILTER DIGESTER CHLORINE CONTACT TANK EFFLUENT DISPOSAL (OUTFALL OR LAND APPLICATION) DRYING BEDS (c) INCINERATION b) COMPOSTING LANDFILL ULTIMATE SLUDGE LESZ91dQ DISPOSAL ALTERNATIVES `—� i WASTEWATER --- SLUDGE FLOW SCHEMATIC ......••. FILTRATE 9 SUPERNATANT ALTERNATIVE SW -3 TOWN OF SOUTHOLD — INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. CONSULTING ENGINEERS PLANNERS and ENVIRONMENTAL SCIENTISTS MELVILLE N Y F AA'JIRMJC[) A,.c �. IHOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. 1 waste. To keep these odors to a minimum, the primary settling ' and aeration tanks will require some type of odor control. ' An appropriate sludge treatment system will include gravity thickening, anaerobic digestion and dewatering with the use of ' sludge drying beds with ultimate disposal at a sanitary landfill. Ultimate disposal is discussed in Section 4.3. In order to implement this alternative, the installation ' of new primary settling tanks, aeration tanks and additional sludge treatment facilities would be required. Utilization of ' existing structures would include the final settling tank, chlorination system, outfall sewer and the sludge drying beds. ' D.2 ALTERNATIVE SW -4 - Rotating Biological Discs and ' Effluent Polishing (Combined Flow) Modifying the existing treatment plant by the installation ' of a chemical addition system for scavenger waste, a Rotating Biological Disc (RBD) unit immediately after the Imhoff tanks ' and an effluent polishing process after chlorination is an ' alternative in treating the combined scavenger waste -wastewater flows. ' The RBD unit process reduces high BOD loadings into a range where an aerated lagoon system can operate efficiently. However, the Imhoff tanks are not capable of removing a signi- ficant percentage of solids. Therefore, the.aerated lagoon ' and/or final settling tank would become overloaded with solids, ' resulting in depletion of the oxygen supply and large quantities of solids in the effluent overflow. 1 4.127 i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. Implementation of this alternative would result in many operational problems which in turn reduce the efficiency of the plant. Again, odor problems will exist in the Imhoff tank and aerated lagoon areas causing the need for odor control. A selected sludge train includes anaerobic digestion and additional sludge drying beds. Ultimate sludge disposal will be at a sanitary landfill. A flow schematic of Alternative SW -4 can be found on Figure 4.22. D.3 ALTERNATIVE SW -5 - Rotating Biological Discs and Activated Sludge (Combined Flow) Alternative SW -5 is the same process as Alternative SW -3 with the addition of the rotating biological disc (RBD) process prior to the activated sludge process. The RBD units will be operated as a roughing filter. The RBD reduces the carbonaceous BOD, therefore providing a buffer for the activated sludge system and allowing for consistent BOD removal. The primary settling tanks need to be oversized in order to provide suf- ficient settling due to the high solids loading that is antici- pated. An appropriate sludge treatment system comprised of gravity thickening, anaerobic digestion, dewatering by drying beds and ultimate disposal by sanitary landfilling will be further dis- cussed in Section 4.3. A flow schematic for this alternative is located on Figure 4.23. 4.128 SCAVENGER WASTE FROM HEAD END CHEMICAL FACILITY ADDITIVE A FLOCCULATION EFFLUENT Cl2 DISPOSAL IMHOFF RBD AERATED FINAL EFFLUENT (OUTFALL • TANK UNIT LAGOONS SANK G POLISHMI6LANDRCONT Ct�O�CT SAND FILTER APPLICATION) +TANK SLUDGE CARBON AD. RAW WASTEWATER Ij= LEGEN c 1�s��N1 --- WASTEWATER SLUDGE ••••••••. FILTRATE 6 SUPERNATANT •• DRYING BEDS: FILTRATE S SUPERNATANT (c) INCINERATION �- i --(o) LANDFILL ULTIMATE SLUDGE DISPOSAL ALTERNATIVES FLOW SCHEMATIC ALTERNATIVE SW -4 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE. N.Y HOLZMACHER, McLENDON & MURRELL, P.C. / 1-12M CORP. FAP-�-.I DALE CONSULTING ENGINEERS PLANNERS a^d ENVIRONMENTAL SCIENTISTS c m N N SCAVENGER WASTE FROM HEAD END FACILITY I RAN► WASTEWATER CHEMICAL ADDITION B FLOCCULATION q2 EFFLUENT PRIMARY ROTATING AERATION FINAL DISPOSAL SETTLING BIOL OGrAL SETTLMiG ( OUTFALL OR TANK DISC TANKS TANKS CHLORINE APPLLAND ICATION) CONTACT t RAS I TANK ACT SLUDGE (— Ps wAs T S r LEGEN ---�� WASTEWATER = SIN SLUDGE -- -� Will IICIERATIai i I tGRAVITY DIGESTER 1 (b) COMPOSTING r _ +� o) LANDFILL • ULTIMATE SLUDGE lRYING BEDS ( DISPOSAL FILTRATE S SUPERNANT - ALTERNATIVES 00....••• FILTRATE & SUPERNATANT FLOW SCHEMATIC ALTERNATIVE SW -5 TOWN OF SOUTHOLD — INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY MELVILLE. N.r. HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. rAFIKAT41GOwLE Y rprrJSULTING ENGINEERS PLANNERS ago ENVIRONMENTAL SCIENTISTS In Z5 c M m N W HOLZMACHER, MCLENDON and MURRELL, P.C. / H2M CORP. Construction of this alternative would include the in- stallation of a RBD unit, and primary settling tanks, modifi- cation of the aerated lagoons and construction of additional sludge treatment facilities. Existing structures, such as the ' final settling tank, chlorine facilities, outfall sewer and ' the sludge drying beds would continue to be utilized. D.4 ALTERNATIVE SW -6 - Primary Treatment, Rotating Bio- logical Discs and Effluent Polishing (Combined Flow) Alternative SW -6 utilizes preliminary treatment, primary ' treatment and the rotating biological disc (RBD) process to treat scavenger wastes separately to reduce the waste strength to that of a typical raw wastewater. This flow is then com- bined with the raw wastewater collected from the sewered area and treated by the existing system. Minor modifications and/or ' additional equipment added to the existing plant would increase its capability to treat high organic loadings that may enter the plant. Additional aerators would be provided in the aerated ' lagoon to supply sufficient air to meet the additional oxygen demands imposed by scavenger wastes. A gravity sand filter ' would also be installed as an effluent polishing process to ' provide additional treatment to insure that the plant will meet SPDES discharge limitations. ' Scavenger waste would receive chemical addition, floccula- tion, primary settling and biological treatment via RBD units prior to being combined with the raw wastewater. 4.131 HOLZMACHER, McLENDON and MURRELL, P.C. ! H2M CORP. The sludge treatment scheme includes anaerobic digestion, ' dewatering on open and covered drying beds and ultimate disposal ' via landfilling. Thickening would not be required due to the high solid content obtained from the Imhoff and primary settling ' tanks. A flow schematic of Alternative SW -6 is located on Figure ' 4.24. Implementation of this system requires the construction of a flocculation tank, primary settling tank, RBD units, sand ' filter and anaerobic digester. Odor control facilities would be required for the settling tank and RBD units. ' The entire existing treatment facility will continue to be utilized with additional aerators and covered sludge beds ' required. ' E. ALTERNATIVE SW -7 - Aerobic Treatment - RBD Alternative SW -7, as shown schematically in Figure 4.25, tutilizes RBD units to reduce the carbonaceous BOD. Nitrifi- cation also occurs when sufficient detention time is provided. Preceding the RBD units, settling would be required. The ' operation would consist of chemical addition and mixing, floc- culation and sedimentation. After the RBD units, a final ' settling tank would be required. The effluent from the system would flow to a chlorine contact tank for disinfection and the final effluent would be discharged into an outfall sewer. ' Primary and secondary sludges will be stabilized and de - watered by gravity thickening, anaerobic digestion and drying ' beds. 4.132 m m m m m m m m m m m m m m m m m r CHEMICAL' ADDITION SCAVENGER WASTE � AR RBD HEAD�END FACILITY �I� : SCAVENGER WASTE AT 200 -300 � q/1-800 ... PRIOR TO COMBINING WITH RAW WASTEWATER EFFLUENT ! RAIN WASTEWAITER TAIM F AERA600N FIS C12 SANG (OUTFALL DISPOSAL SETTLING FILTER LAND . (ADD EXTRA APPLICATION) 1 I AERATORS) (c) INCINERATION i L- ANAEROBIC (b) COMPOSTING DIGEST ION ' LESS 1 1 --! WASTEWATER 4cl-i SLUDGE F(s) LANDFILL ULTIMATE SLUDGE SLUDGE ••••••••• FILTRATE 8 SUPERNATANT DISPOSAL ALTERNATIVES DRYING BEDS (ADDITIONAL) FLOW SCHEMATIC ALTERNATIVE SW -6 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPIORT WASTEWATER FACILITIES STUDY MELVILLE. N. V HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. °ARM�cALE N, ;NVERCONSULTING ENGINEERS. PLANNERS and ENVIRONMENTAL SCIENTISTS 1,E.Nl ,— N v 0 c Z m N FLOW SCHEMATIC �+ r ALTERNATIVE SW -7 } TOWN OF SOUTHOLD - INC. VILLAGE OF GREENP'ORT MAR 3 01981a -' , WASTEWATER FACILITIES STUDY i rneLvILLE. N . HOLZMACHER. MCLENDON & MURRELL. P.C. / H2M CORP. GAPJ�AF '. SULT NG E%G!•,=__�c PLANNEAS a^c ENVPOr,ME%TAL SCIF:NT!STS CHEMICAL ADDITION 8 FLOCCULATION SCAVENGER WASTE PRIMARY Cl2 EFFLUENT DISPOSAL FROM HEAD END SETTLING RBD SETTLING --*[]—*(OUTFALL OR LAND APPLICATION) FACILITY r '• r T • " - - - SLUDGE r • : ,1 (c) INCINERATION i mKwUM FILTER AEROBIC � (b) COMPOSTING DIGESTER .: LEGEND + T ; Q) LANDFILL ULTIMATE SLUDGE ---� WASTEWATER DRYING BEDS: DISPOSAL ALTERNATIVES +•�•.r� i SLUDGE ..................................... ........... .......... i ................................. d .•••.•... FILTRATE IS SUPERNATANT FILTRATE A SUPERNATANT FLOW SCHEMATIC �+ r ALTERNATIVE SW -7 } TOWN OF SOUTHOLD - INC. VILLAGE OF GREENP'ORT MAR 3 01981a -' , WASTEWATER FACILITIES STUDY i rneLvILLE. N . HOLZMACHER. MCLENDON & MURRELL. P.C. / H2M CORP. GAPJ�AF '. SULT NG E%G!•,=__�c PLANNEAS a^c ENVPOr,ME%TAL SCIF:NT!STS 1 HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. ' Odor control will be required at the primary settling tank and RBD units, similar to Alternative SW -6. ' F. ALTERNATIVE SW -8 - Anaerobic/Aerobic Treatment The anaerobic/aerobic treatment system employs high rate anaerobic digestion for solids degradation and stabilization. ' Further, the anaerobic stage of the process should improve pro- cess control for the secondary stage of aeration by minimizing the effects from shock -loading conditions and from the vari- ability of the properties of scavenger waste. The aerobic ' design of the aerobic stage is based on the biochemical oxygen demand to be removed. The flow schematic of Alternative SW -8 is shown in Figure 4.26. Dewatering of sludge can be accomplished utilizing a blend- ing tank that mixes sludge from the anaerobic digester with sludge from the settling tank. Filtrate from the dewatering operations would require further treatment that can be obtained ' by returning the filtrate to the head end of the Greenport STP. G. ALTERNATIVE SW -9 - Chlorine Oxidation-Purifax S stem ' BIF Purifax Inc., a unit of the General Signal Corporation, markets a fairly compact self-contained chemical oxidizer. This ' system employs the principal of chemical oxidation at low pres- sure and normal temperatures. The system treats scavenger wastes with chlorine gas to form hypochlorous acid and nascent oxygen, ' and thereby, converts organic matter into stable non -odorous sludge. ' 4.135 HEAT FIRST STAGE ANAEROBIC DIGESTER/ SCAVENGER WASTE FROM HEAD END FACILITY SLUDGE CH4 SUPERNATANT r SECOND ` STAGE ANAEROBIC , DIGESTER, 'TO SLUDGE TRAIN TO INFLUENT END OF EXISTING STP AERATED LAGOON FLAW SCHEMATIC ALTERNATIVE SW- 8 TOWN OF SOUTHOLD-INC. VILLAGE OF GREENPORT WASTE WATER FACILITIES STUDY FINAL SETTLING MELVILLE. N V HOLZMACHER, McLENDON & MURRELL. P.C. / H2M CORP. �oR•a^ ,7a -F TIIJFI`JGI'JEERS PLAN'4ERSandENVIRONMENTAL SCIFN'ISTS Fa ca G TO SLUDGE TRAIN G) C m z 'o N IHOLZMACHER, McLENDON and MURRELL, P.C. i H2M CORP. ' could be treated at the existing Greenport STP. H. ALTERNATIVE SW -10A & SW -10B - Natural Systems ' Two novel sewage treatment systems are in operation at the Brookhaven National Laboratory. Both are closed natural systems ' and are described as the M/M/P (Marsh/Meadow/Pond) and the M/P ' (Marsh/Pond) systems. In the M/M/P system, raw sewage and septic wastes are ' equalized and screened. The wastewater is then degritted and comminuted. The wastewater is subsequently aerated and pumped to a distribution header, feeding an overflow box at the heads ' of two sloped meadows. The two meadows are alternated, with one in operation while the other is being dried for crop har- vesting. After flowing by gravity through the sloped meadow, the wastewater then enters the marsh which merges with the meadow. Various biota are available for the planted marsh. ' The marsh then terminates in a stabilization pond which is stocked with a harvestable aquatic species. A common head is ' maintained in both the marsh and pond. It is at this point that the treated wastewater can be recharged to the groundwater ' 4.137 ' Figure 4.27 depicts a flow schematic for the Purifax system. This system consists of chlorine oxidizers, chlorinators, evapo- rators, sludge feed pumps, disintegrators and associated acces- sories. ' Effluent from the chlorine oxidizers can then be dewatered by either: (a) sand drying beds; or (b) flotation thickening and vacuum filtration. The filtrate from the dewatering operation ' could be treated at the existing Greenport STP. H. ALTERNATIVE SW -10A & SW -10B - Natural Systems ' Two novel sewage treatment systems are in operation at the Brookhaven National Laboratory. Both are closed natural systems ' and are described as the M/M/P (Marsh/Meadow/Pond) and the M/P ' (Marsh/Pond) systems. In the M/M/P system, raw sewage and septic wastes are ' equalized and screened. The wastewater is then degritted and comminuted. The wastewater is subsequently aerated and pumped to a distribution header, feeding an overflow box at the heads ' of two sloped meadows. The two meadows are alternated, with one in operation while the other is being dried for crop har- vesting. After flowing by gravity through the sloped meadow, the wastewater then enters the marsh which merges with the meadow. Various biota are available for the planted marsh. ' The marsh then terminates in a stabilization pond which is stocked with a harvestable aquatic species. A common head is ' maintained in both the marsh and pond. It is at this point that the treated wastewater can be recharged to the groundwater ' 4.137 CHLORIN STORAGE EVAPORATOR 8� CHLORINATOR CL2 SCAVENGER WASTE PURIFAX 10 1 FROM HEAD UNIT END FACILITY L.5EN �--�— WASTEWATER SLUDGE •••••••• FILTRATE & SUPERNATANT DRIED SLUDGE CAKE SAND DRYING TO LANDFILL BEDS ..8611.92819910 FILTRATE FILTRATE EQUALIZATION TANK FLOW SCHEMATIC ALTERNATIVE SW- 9 TOWN OF SOUTHOLD - INC. VILLAGE OF GREENPORT WASTEWATER FACILITIES STUDY TO HEAD END 'OF EXISTING GREENPORT S.T P. MELVILLE. 04 HOLZMACHER, McLENDON & MURRELL, P.C. / H2M CORP. FARMP4r DASE CONSULTING ENGINEERS PLANNERS and ENVIRONMENTAL SCIENTISTS Ft FREAD IHOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' table. The entire system is lined w' y in with either polyvinyl chloride ' (PVC) or polyethylene (PE) which prevents seepage to the ground- water table until treatment is complete. The M/P system is identical to that previously described, except that no meadow is involved. It requires 50 percent less land, but does not yield a cash crop. Both systems reportedly ' can achieve groundwater recharge limits with the M/M/P system slightly out -performing the M/P system. The major advantages to these systems are that they generate little or no sludge, ' they require comparatively little land, and have very low opera- ting costs. The major disadvantage is that these systems have ' never been demonstrated on septic tank (scavenger) wastes alone. The preliminary steps required before operation would appear ' to be equivalent to that required for the rotating biological ' disc (RBD) scheme. In addition, the effluent would also require chlorination before recharge. It has also been indicated(l) that chemical polishing might be required for strong sewages between the pond overflow and the recharge basins. For the ' wastewaters treated thus far by these systems, BOD, solids and ' nitrogen removals have been adequate to meet standards. However, the characteristics of the waste were much weaker than that which I would be anticipated from scavenger waste. Until such time as ' (1) Meadow/Marsh Systems as Sewage Treatment Plants, Maxwell M. Small, Brookhaven National Laboratory, November 1975. 1 4.139 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. it can be established that these natural systems can adequately ' treat high strength septic waste, which receives significant percentages of its load from restaurant and commercial sources, ' such natural systems cannot be recommended. 4.4.7 Regional Treatment - Combined Treatment with Shelter Island The neighboring Town of Shelter Island has recently shown ' an interest in jointly treating scavenger waste with the Town ' of Southold. It would be financially advantageous for the Town of Southold to combine efforts in order to benefit from the economy of scale achieved by the increase in facility capacity. The present unsewered population of Shelter Island is ap- proximately 1,790 persons. The population projection for the year 2005 is 4,240. Again, if we assume the implementation of ' a septic tank management plan, it is estimated that the scaven- ger waste flow will be .84 mgpy. Combining the projected flow rates for Southold and Shelter Island, the capacity of the pro- posed treatment facility would be increased from 17,700 gallons per day to 20,000 gallons per day. Table 4.15 summarizes the ' projected scavenger waste volumes for both the Town of Southold I and Shelter Island. 4.4.8 Screening of Scavenger Waste Treatment Alternatives A matrix system was devised to display the various scaven- ger waste treatment processes previously described. The matrix, shown on Table 4.16, was developed to serve as a guide for com- parative screening since it provides a quantitative summary of ' judgments resulting from screening of qualitative information. ' 4.140 TABLE 4. 15 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT PRESENT AND FUTURE SCAVENGER WASTE FLOW TOWN OF SOUTHOLD C. 10 Town of Southold with STMP (4) Town of Shelter Island (2) 16,300 2,717,000 gpy 2,140 258,000 gpy - 350 1,790 18,114 3,019,000 gpy 32,356 5,393,000 gpy 11990 287,000 gpy 4, 240 661,000 gpy E. PRESENT PRESENT 1985 1985 2005 2005 UNSEWERED SCAVENGER WASTE UNSEWERED SCAVENGER WASTE UNSEWERED SCAVENGER WASTE POPULATION (1) FLOW POPULATION (3) FLOW POPULATION (3) FLOW A. Town of 20,239 1,553,000 gpy 23,814 1,726,000 gpy 38,056 3,083,000 gpy Southold -3,940 COMM. -5,700 -5,700 1,118,000 16,300 TOTAL 18,114 32,356 7,359,000 B. Commercial COMM. 505,900 gpy 708,000 gpy 1,118,000 gpy Waste 1980 population - L.I.L.C.O. Population Survey, 1979. Adjusted for 1980. (2) C. 10 Town of Southold with STMP (4) Town of Shelter Island (2) 16,300 2,717,000 gpy 2,140 258,000 gpy - 350 1,790 18,114 3,019,000 gpy 32,356 5,393,000 gpy 11990 287,000 gpy 4, 240 661,000 gpy E. Town of 1,790 358,000 gpy 1,990 398,000 gpy 4,240 848,000 gpy Shelter Island with STMP (4) F. Southold & 18,090 3,075,000 gpy 21,790 3,417,000 gpy 36,596 6,241,000 gpy Shelter Island COMM. 505,900 708,000 1,118,000 Combined TOTAL 3,580,900 4,125,000 7,359,000 (with STMP)(4) (1) 1980 population - L.I.L.C.O. Population Survey, 1979. Adjusted for 1980. (2) Based on Average Per Capita Flow Rate of 4 Eastern Townships (114 gpcpy). (3) Based on N.S.R.P.B. 208 Study. (4) Based on each septic system being pumped once every 3 years; Average 1,500 gal. per system; 3 persons per household in Southold and 2.5 per household in Shelter Island; Adjusted for expansion of commercial land use. 4.141 SCREENING FACTORS Abatement of Existing Groundwater Pollution Problem Monetary Cost Effluent Quality Process Reliability Process Flexibility Stability of Waste Sludge Required Operator Skills Site Modification to Existing Units Advantages Disadvantages 'T'ABLF 4.16 GPFFNPORT - SOTJTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT SCREENING MATRIX FOR THE SCAVENGER WASTE TREATMENT ALTERNATIVES NO ACTION TRANSPORT PURIFAX ALT. ALT. ALT. ALT. ALT. ALT. ALT. ALT. ALT. ALT. SW -1 SW -2 SW -3 SW -4 SW -5 SW -6 Sh'-7 SW -8 SW -9 SW -10 NG 0 NG 0 0 0 0 0 0 0 3 2 3 2 2 3 3 0 2 0 0 2 2 2 1 3 1 1 2 2 2 2 2. 2 2 1 2 2 2 2 2 2 2 2 2 3 1 3 1 1 1 1 3 2 3 1 1 1 2 -1.5 -1 -1 -1.5 -1 -.5 -.5 4 6 6 2 2 2 4 NG TOTAL NG NG 16-5 19 19 9.5 12 14.5 17.5 NG 1. Abatement of existing Water Pollution Problems; Resolved -0, Significant -4, Moderate -6, Minimal -8, Insiqnificant-NG 2. Monetary Costs; Minimal -1, Moderate -2, Significant -3, Expensive -4. 3. Effluent Quality; 0ood-0, Moderate -3, Poor -4. 4. Process Reliability; Reliable -1, Conditional -2, unreliable -3. 5. Process Flexibility; Extensive -1, Moderate -2, Limited -3. 6. Stability of Waste Sludge; Very Stable -1, Stable -2, Unstable -3. 7. Required Operator Skills; Good Skills -1, Highly Skilled -3. 8. Site Modification for Accommodation w/ Fxistinq Units; Insignificant -0, Minimal -1, Moderate -2, Extensive -3. 9. Advantages; -Number of advantages x(- 0.5). 10. Disadvantages; Number of disadvantages x (2). 11. NG -denotes that the alt. will not be compared w/the remaining alts. due to the reasons) cited in the report. 12. N/A -Not Applicable. 4.142 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. IThe matrix functions are a series of discrete decisions. ' Rating factors include: abatement of existing groundwater pollution problem; monetary cost; effluent quality; process ' reliability; process flexibility; stability of waste sludge; required operator skills; site modification for accommodation ' with existing units; advantages and disadvantages. Each alter- native is screened with respect to these various factors and assessed a rating. ' The detailed commentary which provided the substantiation for each of the judgments in the matrix is contained in the ' following sections. ' With Shelter Island estimated to contribute only 11.5 percent of the combined scavenger waste flow from the two ' towns, it seems advantagous for Southold to combine efforts with Shelter Island. This should provide an economy of scale ' and, in turn, reduce their costs. The design and associated ' costs of the following scavenger waste treatment alternatives are based on a combined Southold -Shelter Island flow. Within ' the cost-effective analysis section, a comparison of treatment with and without Shelter Island will be provided. ' A. ALTERNATIVE SW -1 - No Action - Continue Existing Disposal Methods As previously indicated, continuing the present disposal ' methods will not be legally implementable. This alternative will not resolve existing groundwater pollution problems and ' is unacceptable. This alternative will be assigned a rating of NG and will not be evaluated further. 4.143 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. r C 11 0 n 0 as follows: 1. Abatement of Existing Groundwater Pollution Problem: Resolved - 0 2. Monetary Cost: Expensive - 4 3. Effluent Quality: Not Applicable - N/A 4. Process Reliability: Conditional - 2 5. Process Flexibility: Moderate - 2 6. Stability of Waste Sludge: Not Applicable - N/A 7. Required Operation Skills: Not Applicable - N/A 8. Site Modification of Existing Units: Moderate - 2 9. Advantages (1 x -0.5 = 0.5) a. totally removes waste from study area 10. Disadvantages (2 x 3 = 6) a. excessive operating costs b. probable increase in fuel cost C. possible disruption of disposal if avail- ability of fuel decreases 11. Total . . . . • • • • • • • • • • • • • • • . 15.5 4.144 B. ALTERNATIVE SW -2 - Transporting to Another Treatment ' System ' Implementation of Alternative SW -2 would completely re- solve the groundwater pollution problem which presently exists ' from scavenger waste disposal. However, annual operating costs associated with this alternative are such that the total annual ' cost is greater than all other alternatives. With the increases ' in cost of fuel becoming unpredictable, it is difficult to con- fidently estimate operating costs through the 20 year planning ' period. The total estimated annual cost is $336,300., subject to the above concerns. So the screening factors were evaluated r C 11 0 n 0 as follows: 1. Abatement of Existing Groundwater Pollution Problem: Resolved - 0 2. Monetary Cost: Expensive - 4 3. Effluent Quality: Not Applicable - N/A 4. Process Reliability: Conditional - 2 5. Process Flexibility: Moderate - 2 6. Stability of Waste Sludge: Not Applicable - N/A 7. Required Operation Skills: Not Applicable - N/A 8. Site Modification of Existing Units: Moderate - 2 9. Advantages (1 x -0.5 = 0.5) a. totally removes waste from study area 10. Disadvantages (2 x 3 = 6) a. excessive operating costs b. probable increase in fuel cost C. possible disruption of disposal if avail- ability of fuel decreases 11. Total . . . . • • • • • • • • • • • • • • • . 15.5 4.144 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' C. ALTERNATIVE SW -3 - Activated Sludge Combined Flow By over -designing the primary settling tank for solids handling and designing the aeration tank at 35 pounds -BOD -5/ 1,000 cf/day, the effluent discharge limitations should con- sistently be met. Assuming a 35 percent BOD removal in primary settling, a loading of 312 pounds of BOD per day can be ex- pected to enter the aeration tank. Gravity thickening is ' required to increase the solids content from approximately 2 - 3 percent solids to 8 - 9 percent solids. The total esti- mated annual cost is $241,900. ' The screening factors were evaluated as follows: 1. Abatement of Existing Groundwater Pollution Problem: Resolved - 0 ' 2. Monetary Cost: Significant - 3 ' 3. Effluent Quality: Good - 0 4. Process Reliability: Reliable - 1 ' 5. Process Flexibility: Moderate - 2 6. Stability of Waste Sludge: Stable - 2 7. Required Operator Skills: Highly Skilled - 3 ' 8. Site Modifications to Existing Units: Extensive - 3 9. Advantages (3 x -0.5 = -1.5) ' a. reliable process b. resistance to shock loadings C. high quality effluent 10. Disadvantages (2 x 2 = 4) ' a. odor problem at aeration tank b. requires frequent monitoring 11. Total . . . . . . . . . . . . . . . . . . . . . . 16.5 4.145 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 11 ' D. Alternative SW -4 - Addition of RBD and Effluent Polishin to Existing System - (Combined Flow) ' With Alternative SW -4 utilizing the Imhoff tanks for primary settling, sufficient settling may not take place. Effluent from ' the Imhoff tanks may be too strong to be efficiently treated by ' the existing aerated lagoon. Operational efficiencies will de- crease due to the extra solids loading from scavenger wastes. ' The elimination of this alternative is suggested due to the uncertainty of achieving sufficient treatment to meet dis- charge limitations. The total estimated annual cost is $231,300. ' The screening factors were evaluated as follows: 1. Abatement of Existing Groundwater Pollution Problem: Resolved - 0 ' 2. Monetary Cost: Moderate - 2 ' 3. Effluent Quality: Moderate - 2 4. Process Reliability: Unreliable - 3 ' 5. Process Flexibility: Moderate - 2 6. Stability of Waste Sludge: Stable - 2 ' 7. Required Operator Skills: Good Skills - 1 ' 8. Site Modification to Existing Units: Moderate - 2 9. Advantages (2 x -0.5 = -1) ' a. ease of upgrading with additional RBD units b. full utilization of existing system ' 10. Disadvantages (3 x 2 = 6) a. overload Imhoff tanks ' b. odor problem in aeration system C. low quality effluent expected 11. Total . . . . . . . . . . . . . . . . . . . . . 19 4.146 HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. E. ALTERNATIVE SW -5 - RBD Plus Activated Sludc3e 1'r(.)ctoss As with Alternative SW -3, oversizi.ng the primary settl_iny tank will provide for the removal of approximately 70 percent of the suspended solids. The rotating biological disc units ' will insure that BOD removal is accomplished. The design of Alternative SW -5 will provide excellent removal efficiencies, ' enabling the plant to meet the discharge limitations. Again, ' gravity thickening is required to increase the solids content of the sludge from 2 - 3 percent to 8 - 9 percent solids. ' The total estimated annual cost is $267,700. The screening factors were evaluated as follows: 1 I. Abatement of Existing Groundwater Pollution Problem: Resolved - 0 ' 2. Monetary Cost: Significant - 3 3. Effluent Quality: Good - 0 4. Process Reliability: Reliable - 1 ' 5. Process Flexibility: Moderate - 2 6. Stability of Waste Sludge: Stable - 2 ' 7. Required Operator Skills: highly Skilled - 3 8. Site Modification to Existing Units: Extensive - 3 9. Advantages (2 x -0.5 = -1) ' a. resistance to shock loading b. ease of upgrading with additional RBD units ' 10. Disadvantages (3 x 2 = 6) a. gravity thickening required b. little utilization of existing system 'C. requires frequent monitoring 11. Total . . . . . . . . . . . . . . . . . . . . . 19 '4.147 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. F. ALTERNATIVE SW -6 - Primary -RBD Treatment Prior to Combined Flow The design of Alternative SW -6 will require pretreatment of scavenger waste such that its characteristics are similar to that of raw wastewater. The BOD -5 and suspended solids concentration will be in the range of 200 to 300 mg/1. This existing Greenport STP system will meet effluent limitations with the addition of extra aerators and a sand filter. The total estimated annual cost is $213,200. The screening factors were evaluated as follows: 1. Abatement of Existing Groundwater Pollution Problems: Resolved - 0 2. Monetary Cost: Moderate - 2 3. Effluent Quality: Good - 0 4. Process Reliability: Reliable - 1 5. Process Flexibility: Moderate - 2 6. Stability of Waste Sludge: Stable - 2 7. Required Operator Skills: Good Skills - 1 8. Site Modifications to Existing Units: Minimal - 1 9. Advantages (3 x -0.5 = -1.5) a. full utilization of existing units b. high quality effluent C. ease of upgrading with addition of RBD units 10. Disadvantages (1 x 2 = 2) a. possible clogging of filter if large solids loadings occur. 11. Total . . . . . . . . . . . . . . . . . . . . . 9.5 4.148 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. G. ALTERNATIVE SW -7 - Aerobic Treatment - RBD The designing of Alternative SW -7 will depend on the degree of treatment required. The sizing of the RBD units will depend on whether nitrification is required in addition to carbonaceous BOD removal. The total estimated annual cost is $219,500. The screening factors were evaluated as follows: 1. Abatement of Existing Groundwater Pollution Problem: Resolved - 0 2. Monetary Cost: Moderate - 2 3. Effluent Quality: Moderate - 2 4. Process Reliability: Conditional - 2 5. Process Flexibility: Extensive - 1 6. Stability of Waste Sludge: Stable - 2 7. Required Operator Skills: Good Skills - 1 8. Site Modification to Existing Units: Minimal - 1 9. Advantages (2 x -0.5 = 1) a. ease of plant expansion with RBD units b. minimal operational needs 10. Disadvantages (1 x 2 = 2) a. Sensitive to temperature 11. Total . . . . . . . . . . . . . . . . . . . . . 12.0 H. ALTERNATIVE SW -8 - AerobicZAnaerobic Treatment Alternative SW -8 might prove to be an ineffective selection, since (a) high ammonia build-up might occur in the digester, caus- ing digester upset; and (b) pilot program would be required to as- certain viability of alternative. The total estimated annual cost is $232,600. 4.149 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. The screening factors were evaluated as follows: 1. Abatement of Existing Groundwater Pollution Problems: Resolved - 0 2. Monetary Cost: Significant - 3 3. Effluent Quality: Moderate - 2 4. Process Reliability: Conditional - 2 5. Process Flexibility: Moderate - 2 6. Stability of Waste Sludge: Stable - 2 7. Required Operator Skills: Good Skills - 1 8. Site Modification to Existing Units: Minimal - 1 9. Advantages (1 x -0.5 = -0.5) a. little operation needed 10. Disadvantages (2 x 1 = 2) a. poor effluent quality 11. Total . . . . . . . . . . . . . . . . . . . . .14.5 I. ALTERNATIVE SW -9 - Chemical Oxidation The utilization of the chemical oxidation process, widely known by its trade name "Purifax," has been proven effective in treating scavenger waste. Several facilities within the region presently use Purifax in treating scavenger waste. However, the Nassau -Suffolk 208 Technical Advisory Committee has recently ob- jected to the use of Purifax on Long Island, due to possible en- vironmental problems with sludge disposal and the impact of chlorinated organics on surface waters. In addition, Suffolk County Department of Health Services is concerned about the transportation of large quantities of chlorine through Suffolk County. The total estimated annual cost is $199,100. 4.150 HOLZMACHER. McLENDON and MURRELL. P.C. / H2M CORP. 11. Total . . . . . . . . . . . . . . . . . . . . . . 17.5 J. ALTERNATIVE SW -10 - Natural Systems ' As previously indicated, natural treatment systems have been ' proven effective for wastewater treatment and for combined septage and wastewater. However, natural systems have not been effective with wastewater to septage ratios of less than 10:1. Therefore, if this alternative is to be utilized, wastewater would have to ' be diverted from the sewage treatment plant to the scavenger ' waste plant. The capacity of the natural treatment system would then be ten times the scavenger waste flows, which in turn, in- crease the land requirements for this facility. Alternative SW -10 has been given a rating of NG due to the fact that the required ' effluent quality cannot be achieved. 1 4.151 ' The screening factors were evaluated as follows: 1. Abatement of Existing Groundwater Pollution Problems: Resolved - 0 2. Monetary Cost: Significant 3 - 3. Effluent Quality: Moderate - 2 4. Process Reliability: Conditional - 2 ' 5. Process Flexibility: Moderate - 2 6. Stability of Waste Sludge: Stable - 2 ' 7. Required Operator Skills: Good Skills - 1 'B. Site Modifications to Existing Units: Moderate - 2 9. Advantages (1 x -0.5 = -0.5) ' a. able to run intermittently 10. Disadvantages (2 x 2 = 4) ' a. environmental problems with sludge disposal b. 208 TAC will not accept alternative 11. Total . . . . . . . . . . . . . . . . . . . . . . 17.5 J. ALTERNATIVE SW -10 - Natural Systems ' As previously indicated, natural treatment systems have been ' proven effective for wastewater treatment and for combined septage and wastewater. However, natural systems have not been effective with wastewater to septage ratios of less than 10:1. Therefore, if this alternative is to be utilized, wastewater would have to ' be diverted from the sewage treatment plant to the scavenger ' waste plant. The capacity of the natural treatment system would then be ten times the scavenger waste flows, which in turn, in- crease the land requirements for this facility. Alternative SW -10 has been given a rating of NG due to the fact that the required ' effluent quality cannot be achieved. 1 4.151 HOLZMACHER, McLENDON and MURRELL, P.C. i H2M CORP. ' 4.4.9 Cesspool and Septic Tank Management Plan (CSTMP) Although there are no specific USEPA or NYSDEC require- ments for cesspool and septic tank management, regulatory ' agencies require that a management program be proposed and adopted by the Town of Southold and/or the Town of Shelter Island. With the exception of the Inc. Village of Greenport, the ' remainder of Southold is served by individual on-site septic ' systems. In Shelter Island, aside from the Shelter Island Heights Association, the remainder of Shelter Island is served ' by on-site septic systems. Therefore, in order to regulate the cesspools and septic tanks in both Towns, a CSTMP is re- quired. ' The purpose of a cesspool and septic tank management plan are manifold and include: ' 1. Providing for the protection of the environment by proper installation and management of septic and cesspool ' systems. ' 2. Providing for periodic maintenance of septic tanks and cesspools in order to prolong the life of leaching systems ' and the attendant impacts associated with their failure. 3. Extending the life of the septic leaching system by ' proper management practices might in many instances reduce the need for extensive sewering and its associated costs particularly in sparsely populated areas. ' 4.152 HOLZMACHER, MCLENDON and MURRELL. P.C. / H2M CORP. ' 4. Proper disposal of septic and cesspool wastes in order to safeguard the ground and surface waters from contamination, as well as prevention of public health and nuisance problems associated with improper septage disposal. 5. Provide for an accurate record system which in turn ' can help designate problem areas. The CSTMP should address the following four (4) catagories: ' A. Total Management Responsibility located, to inspect, take water and wastewater samples and to ' 1. Tax, collect service charges, or in some other way 5. raise revenue to finance the management plan operations. ' 2. Perform a survey to locate and establish the number ' of existing on-site systems in the Town of Southold. Another ' approach is to register each on-site system when it requires ' pumping, regardless of whether the system has failed or needs to be cleaned. ' 3. Obtain easements, as may be required, over the primary treatment and effluent disposal sections of an on-site system. 4. Enter outside premises where the on-site system is ' located, to inspect, take water and wastewater samples and to provide routine maintenance or remedy overloaded systems. ' 5. Institute abatement proceedings. 6. Review the need for sewers, when and if needed. ' 7. Adopt and enforce appropriate ordinances governing ' sewage disposal practices. CI' 1 4.153 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. B. Levy annual registration fees, registration numbers ' and decals to private scavenger waste collectors/haulers. Decals must be displayed on all vehicles discharging at the scavenger waste facility. ' 9. Require initial and renewal licensing of septic and cesspool systems and levy a fee for same, as may be established ' by the Town Board. ' 10. Hire consultants and contract for services when required. 11. Enter into contract with other agencies or private parties for disposal of septage effluents. 12. Coordinate a comprehensive drainage basin protection ' program (groundwater monitoring) in conjunction with the Suffolk County Department of Health Services, NYSDEC and other ' regulatory agencies. 13. Require haulers to inform scavenger waste facility operators of the following, prior to dumping waste: (a) Verification as to where the wastes came from should be required via a signed form from residence, com- mercial establishment, etc. Form should give name, address, cause for pumping and approximate volume. (b) Classify type of waste on truck, i.e. residential, commercial, industrial, etc. (c) Give approximate volume from each source obtained in (a) above, if more than one source is on truck. 1 ' 4.154 ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. B. Maintenance ' The Town must be able to ensure that, during the operating ' life of on-site systems, they are properly maintained and func- tioning at their optimal level. ' To accomplish system maintenance, Southold needs to: 1. Issue maintenance permits for individual sites in ' the Town and inspect them annually or as otherwise determined. ' 2. Require that each residence or commercial establish- ment have their septic tank or cesspool pumped once every three ' (3) years of use or as operating experience dictates. The septage will be transported to the scavenger waste treatment ' facility. ' 3. Maintain adequate records. 4. Operate and maintain the scavenger waste treatment facility. C. Environmental Monitoring ' Southold must be able to ensure that the total effect of ' the operations of the sum of the systems within the boundaries of the Town are not degrading the quality of the environment. ' To accomplish environmental monitoring, the Town needs to be able to enter onto property and collect samples from ' the potable water supply well for monitoring purposes. The following periodic sampling schedule is recommended: ' 1. Septic tank influent and effluent composite samples. 2. Grab sample from water supply well or adjacent surface water (for both cesspool and septic tank systems). 1 4.155 1 1 1 1 1 1 1 1 HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. The water sampling program will provide an early warning of potential well contamination (nitrate -nitrogen and/or total coliform MPN). D. Problem Correction The Town must be able to ensure that if a system malfunc- tions, the necessary powers and capabilities for prompt correc- tion of the malfunctioning system are at hand and applied. To accomplish problem correction, the Town must be able to: 1. Declare and abate a nuisance. 2. Recommend correction procedures. 3. Correct a malfunctioning system, and bill the owner, if the homeowner fails to repair the system within a reasonable time set by the Town. 4. Take other measures necessary to resolve problems that concern an area as a whole, rather than an individual malfunction- ing system. For instance, establish alternate on-site or com- munity sewage systems; or provide for the installation of lateral sewers and treatment of wastewater at the regional or sub -regional facilities. 4.156 HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. 5.0 COST-EFFECTIVE ANALYSIS OF VIABLE STRUCTURAL ALTERNATIVE WASTEWATER MANAGEMENT PLANS ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 5.0 COST-EFFECTIVE ANALYSIS OF VIABLE STRUCTURAL AL.TERNATI_VE WASTEWATER MANAGEMENT PLANS ' After screening the various wastewater management alter- natives that were described in Chapter 4.0, the following are the most viable wastewater/scavenger waste management alter- natives: I - NO ACTION ALTERNATIVE ' II - EXPANSION OF THE GREENPORT SANITARY COLLECTION SYSTEM ' III - SUB -REGIONAL TREATMENT AT MATTITUCK Alternative C-2 Rotating Biological Discs (RBD) ' Alternative C-3 Extended Aeration Activated Sludge Alternative C-4 Contact Stabilization Activated ' Sludge Alternative C-5 Complete Mix Activated Sludge Alternative C-6 Marsh -Pond IV - EFFLUENT DISPOSAL (Mattituck and Greenport) ' 1. Outfall Discharge 2. Land Application ' V - SLUDGE DISPOSAL ALTERNATIVE SD Alternative 1 - Sanitary Landfill ' SD Alternative 3 - Composting SD Alternative 4 - Incineration ' VI - SCAVENGER WASTE TREATMENT ALTERNATIVES Alternative SW -2 - Transporting to Other ' Treatment Systems Alternative SW -3 - Activated Sludge Combined Flow at Greenport Alternative SW -4 - RBD & Effluent Polishing, Combined Flow at Greenport ' 5.1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 HOLZMACHER, McLENOON and MURRELL, P.C. / H2M CORP. Alternative SW -5 - RBD - Activated Sludge Com- bined Flow at Greenport Alternative SW -6 - Primary RBD Treatment Prior to Combining with Greenport Alternative SW -7 - Aerobic RBD Treatment Alternative SW -8 - Aerobic -Anaerobic Treatment Alternative SW -10 - Natural System-Marsh/Meadow/ Pond The alternatives described above have been evaluated to ensure that they can provide the basic function for which they were intended. The following sections will further investigate the alternatives based on a cost-effective analysis. 5.2 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' 5.1 Cost -Effective_ Analysis One of the major factors that is utilized in the alter- native selection process is that of monetary costs associated ' with the implementation of a management plan. Federal guide- lines require the selection process to be based on "The Most Cost -Effective Alternative" concept. This can be defined as the waste treatment management system having the lowest present ' worth and/or equivalent annual value, without overriding adverse ' non -monetary costs. The following subsections will analyze each set of alternatives in order to obtain the most cost-effective alternative: ' 5.1.1 Methods and Procedures Cost analysis for this phase of alternative evaluation is ' a comparative process. Given this fact and the number of alter- natives requiring evaluation, the majority of the cost estimates were based on USEPA publications rather than detailed engineer's estimates. These publications include various formulas and curves generated as a result of nationwide surveys. Cost factors were ' applied to these costs to reflect local labor and material costs. The following general assumptions were made to help compare alternatives: ' 1. 1980 was arbitrarily chosen as the design year. An En- gineering News Record Construction Cost Index of 3,130., repre- senting January 1980, was used. 1 5.3 1 1 L i 11 0 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 2. Salvage values for all alternatives were excluded, since accurate data were not attainable without detailed analy- sis and were judged insignificant. The omission of salvage values should not alter the outcome. 3. A service and interest factor of 27 percent was used, representing engineering, contingencies, legal and administra- tion costs and interest during construction. 4. Land costs were based on $10,000. per acre. 5. Cost comparisons were based on the total annual cost which equals the amortized capital cost plus the annual opera- tion and maintenance cost. Amortization was calculated using 7-1/8 percent interest for 20 years. In most cases, cost estimates were derived from various USEPA publications. In some instances, however, assumptions had to be made, costs modified and adjustments to the particu- lar alternative taken into consideration. Due to the large number of alternatives evaluated, it is not feasible to pro- vide the details of all cost estimates, procedures and varia- tions. In all cases, however, the costs were analyzed to en- sure their accuracy for the intended purposes. For similar reasons, all formulas and curves are not duplicated in this document, but may be found in the references. 5.1.2 Expansion of Greenport Collection System - Cost Analysis The construction costs for the collection system, pumping stations and force mains are based on engineering estimates 5.4 HOLZMACHER. McLENDON and MURRELL. P.C. I H2M CORP. recently prepared for another collection system within Suffolk County. The unit costs on which the estimates are based are: ' Pipe Unit Price 6" D.I. Pipe - Force Main $35.00/L.F. 8" V.C. Pipe - Gravity 60.00/L.F. 8" V.C. Pipe - Gravity (Dewatering) 80-OU/L.F. Calculations were executed to determine the most economi- cal sewer layout in order to connect the areas in need of sewer- ing to the existing system. Field observations of the areas were ' used to determine the approximate needs and locations of gravity sewers, force mains and pump stations. Total costs required to expand the Greenport Collection System, to include Conkling Point, ' Pipes Cove, Sterling Basin and North Greenport, are depicted on Table 5.1. 5.1.3 Sub -Regional Treatment - Mattituck Treatment Facility - Cost Analysis As previously discussed in Section 4.2.3, it is questionable ' whether the Mattituck area should be sewered at this time. If the results of the recommended groundwater monitoring program indicate that individual septic systems are severely impacting ' the groundwater quality, then implementation of a sewering plan should commence. Most of the construction and operation and maintenance costs for these facilities were obtained from the USEPA publication entitled "Cost -Effective Wastewater Treatment Systems", dated i 1 5.5 TABLE 5.1 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT PRELIMINARY COST OF EXPANDING EXISTING SEWER SERVICE AREA APPROX. LENGTH OF PIPE (FEET) COLLECTORS CAPITAL PUMPING TOTAL REQ'D (1) FORCE COST SEWER COST ANNUP.L AREA COLLECTORS DEWATERING MAIN CONSTURCTION CAPITAL 0&14 COST (2) Conkling Pt. -- 6,700 12,000 956,000 150,000 5,000 Pipes Coves 1,200 1,500 2,500 280,000 150,000 5,000 Sterling Basin 3,200 2,000 4,800 520,000 150,000 5,000 Ln North Greenport 6,700 -- -- 402,000 -- -- rn SUB -TOTAL 11,100 10,200 19,300 2,158,000 450,000 15,000 Eng., Admin., -- -- -- 583,000 122,00 Legal & Conting. (27%) TOTAL $2,741,000 $572,000 $15,000 $330,800 NOTES: (1) Length of collector requiring dewatering estimated utilizing groundwater and surface elevations. (2) Capital Costs amortized at 7-1/8% interest over 20 yrs. (Crf = 0.095323) HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. July 1975. The costs for the Marsh -Pond Treatment System were ' estimated with the use of the publication "Natural Sewage Re- cycling Systems", dated January 1977. A design sewage flow of 0.5 million gallons per day was utilized in estimating capital ' costs. Table 5.2 summarizes our cost analysis. ' 5.1.4 Sludge - Ultimate Disposal - Cost Analysis Due to the unique local conditions (i.e., sensitivity of ' groundwater quality) and the small quantity of sludge, prelimin- ary cost estimates had to be developed in order to perform the ' cost analysis for the ultimate sludge disposal alternatives. ' Table 5.3 summarizes the cost analysis for sanitary landfill, composting and incineration. The facility costs were based on ' disposing of 1 dry ton of sludge per day. ' 5.1.5 Scavenger Waste Treatment Alternatives - Cost Analysis The construction and operation and maintenance costs for ' Alternatives SW -3, 4, 5, 6, 7 and 8 were obtained from the USEPA publication entitled "Cost Effective Wastewater Treatment System", ' dated July 1975. Preliminary cost estimates were prepared in ' order to perform the cost analysis for Alternatives SW -2 and SW -9. ' The cost estimates are based on a facility designed to handle an average flow rate of 20,000 gallons per day (based on ' a 7 -day week) of scavenger waste. As previously discussed, this ' flow represents the combined waste from Southold and Shelter Is- land, assuming that a cesspool and septic tank management plan ' will be implemented. 1 5.7 ALTERNATIVE ITEM A. Construction Cost - Unit Processes (incl. Sludge Train of anaerobic di estion and drying beds - Effluent Disposal (1? - Site Work, Electr., HVAC, Piping & Mobil. B. SUB -TOTAL C. Enc., Admin, Legal & Conting. (27% of Sub -Total) D. TOTAL CAPITAL COST E. Amortized Capital Cost (2) F. 0 & M Cost 0. TOTAL ANNUAL COST TABLE 5.2 rPFENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT COST ANALYSIS OF MATTITUCK TREATMENT ALTERNATIVES ($ X 103) C -la C -lb C -2a C -2b C -3a C -3b C -4a C -4b C -5a C -5b C-6 1,182 1,549 1,182 1,549 840 1,200 1,919 2,273 1,919 2,273 1,140 295 411 295 411 295 411 295 411 295 411 411 346 346 346 346 346 346 346 346 346 346 446 1,823 2,306 1,823 2,306 1,481 1,957 2,560 3,030 2,560 3,030 1,997 492 623 492 623 400 528 961 818 691 818 539 2,315 2,929 2,315 2,929 1,881 2,485 3,251 3,848 3,251 3,848 2,536 220.7 279.2 220.7 279.2 179.3 236.9 309.9 366.8 309.9 336.8 241.7 68 68 67 67 56 56 86 86 86 86 117 228.7 347.2 287.7 346.2 235.3 292.9 395.9 452.8 395.9 452.8 358.7 (1) Sub -Alternative a. utilizes outfall disposal. Sub -Alternative b. utilizes land application cost based on infiltration - percolation method. (2) Amortized over 20 years ENR Cost Index. = 3,130 Jan., 1980. SOURCES: 1. Wastewater Treatment Facilities for Sewered Small Communities? USEPA, 1977. 2. Natural Sewage Recyclina Systems; Maxwell M. Small, January, 1977. MW 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 TABLE 5.3 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT COST ANALYSIS OF SLUDGE DISPOSAL ALTERNATIVES (BASED ON 1 DRY TONZDAY) ITEM Capital Cost Amoritized (1) Annual Capital Annual O & M LANDFILL DISPOSAL $178,000 (3) 16,900 15,000 TOTAL ANNUAL COST $ 31,900 COMPOSTING (4) $141,000 13,200 25,000 $ 38,400 (2) INCINERATION $692,000 66,000 50,000 $116,000 (2) NOTES: (1) Amortized over 20 yrs at 7-1/8% interest (CRF=0.095323). (2) Excludes any revenues that might be received from sale of end product (ie. compost, electricity). (3) Includes installation of double liner with leachate and methane removal capabilities, as part of an overall liner installation at the landfill in compliance with Part 360. (4) Static Pile Method. 5.9 ' HOLZMACHER, McLENDON and MURRELL. P.C. / H2M CORP. ' Table 5.4 summarizes the cost analysis. The total costs exclude ultimate sludge disposal costs. ' It should be noted that the cost-effective analysis does not take into account the cost of utilizing the Greenport fa- cility. A cost will be associated with utilizing the Green- port STP to provide further treatment of the effluent or by- product of the scavenger waste alternatives. At this time, ' it is felt that this cost could be neglected since the cost- effective analysis is basically a comparative analysis. All ' alternatives will require this "user charge", with the excep- tion of Alternatives SW -2 and SW -10. As previously discussed, ' Alternative SW -2 was eliminated due to high costs and the un- certainty of fuel costs and availability. Alternative SW -10 was eliminated because of its inability to treat scavenger ' waste. Calculation of a cost savings due to economy of scale from combining waste flows with Shelter Island is difficult to perform. The construction cost equations, utilized in the cost-effective analysis, do not provide sufficient accuracy ' in comparing such small changes in flow. Actual savings will be further realized when a more accurate cost estimate is per- formed in the selected plan. ' However, in utilizing the construction cost equation, Table 5.5 was prepared to compare the cost of treating Southold ' flow versus Southold and Shelter Island. As can be seen, an 5.10 TABLE 5.4 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT REPORT SCAVENGER WASTE TREATMENT ALTERNATIVES G. TOTAL ANNUAL $336,300 $241,900 $231,300 $267,700 $213,200 $219,500 $232,600 $199,100 COST :TOTES: 1. Amortized over 20 years at 7-1/8% interest (CRF = .095323) 2. Base year 1980; ENR Cost Index = 3,130, January 1980. 5.11 ITEM SW -2 SW -3 SW -4 SW -5 SW -6 SW -7 SW -8 SW -9 A. Construction Cost -Pretreatment $ 86,000 $136,000 $136,000 $136,000 $136,000 $136,000 $136,000 $136,000 -Unit Processes 780,000 402,000 504,000 682,000 518,000 514,000 950,000 730,000 -Sludge Handling -- 586,000 498,000 586,000 498,000 498,000 118,000 118,000 -Site Elect., -- 162,000 162,000 200,000 162,000 162,000 200,000 162,000 Mobilization., Pipingetc. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - B. Sub -Total $866,000 $1,286,000 $1,300,000 $1,604,000 $1,314,000 $1,31Q,000 $1,404,000 $1,146,000 C. Eng., Admin., 234,000 347,000 351,000 433,000 355,000 354,000 379,000 309,000 Legal, Contin. (27% of Sub -Total) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - D. TOTAL CAPITAL 1,100,000 $1,633,000 $1,651,000 $2,037,000 $1,669,000 $1,664,000 $1,783,000 $1,455,000 COST E. Amortized 104,800 155,700 157,400 194,200 159,100 158,600 170,000 138,000 Capital Cost F. 0 & M Cost 231,500 86,200 73,900 73,500 54,100 60,900 62,600 61,000 G. TOTAL ANNUAL $336,300 $241,900 $231,300 $267,700 $213,200 $219,500 $232,600 $199,100 COST :TOTES: 1. Amortized over 20 years at 7-1/8% interest (CRF = .095323) 2. Base year 1980; ENR Cost Index = 3,130, January 1980. 5.11 1 1 1 1 1 1 1 1 1 1 1 TABLE 5. 5 GREENPORT - SOUTHOLD 201 STUDY ALTERNATIVES EVALUATION & ENVIRONMENTAL ASSESSMENT R1 -?PORT COST COMPARISON OF RECOMMENDED SCAVENGER WASTE TREATMENT ALTERNATIVE SOUTHOLD VS. SOUTHOLD & SHELTER ISLAND FLOW QUANTITIES Southold Flow Cost Item (17,700 apd) Construction Cost - Pretreatment $ 130,000 - Unit Process 465,000 - Sludge Handling 440,000 - Sitework, Elect., 144,000 Mobiliz., Piping, etc. Sub -Total $ 1,179,000 - Engineering, Admin, Legal 318,000 and Conting. - TOTAL CAPITAL $ 1,497,000 - Amortized Capital 142,700 - 0 & M Cost 47,900 - TOTAL ANNUAL COST $ 190,600 Southold's Share $ 190,600 Shelter Island's Share --- Southold & Shelter Island Flow (20,000 apd) $ 136,000 518,000 498,000 162,000 $ 1,314,000 355,000 $ 1,669,000 159,100 54,100 $ 213,200 $ 188,700* 24, 500* *Divisi.on of Cost based strictly on flow proportions. 5.12 HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. ' annual cost savings of $1,900. can be obtained by Southold if efforts are to be combined. This verifies the recommendation ' that Southold should implement a plan with Shelter Island to treat their wastes together. ' 5.13 HOLZMACHER, McLENOON and MURRELL. P.C. / H2M CORP. 6.0 CONCLUSIONS AND RECOMMENDATIONS ' HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 6.0 CONCLUSIONS AND RECOMMENDATIONS ' The Town of Southold and the Inc. Village of Greenport must ' continue to respond to the increasing demands for potable water, agricultural irrigation and water-based recreational opportunities ' within the study area. Numerous structural and non-structural alternatives were evaluated which focus on the preservation of ' the underlying groundwater aquifer and/or surface waters. By ' eliminating and/or reducing groundwater/surface water contamina- tion, the quality of both groundwater and surface water will be ' maintained. The following section provides recommendations as to the structural and non-structural alternatives that should be imple- mented. These recommendations will be further expanded upon in the final document entitled "Selected Plan". The Selected Plan ' will provide procedures and associated costs of implementing non- structural alternatives and include the preliminary engineering ' designs for the recommended wastewater/scavenger waste structural ' alternatives. 6.1 Non -Structural Alternatives ' It has been determined that non-structural alternatives, if ' implemented, will have a very significant impact on the current sources of groundwater/surface water pollution. The following sections highlight the various non-structural alternatives that were examined. i 1 6.1 HOLZMACHER, McLENOON and MURRELL, P.C. •I H2M CORP. 0 6.1.1_ Optimization of the Existing Greenport Sewaqe ' Treatment Facility ' The Facility Plan has evaluated the existing Greenport Sewage Treatment Plant and evaluated various methods to optimize its ' operations and efficiency. Since the recommended treatment al- ternative for scavenger waste disposal utilizes the Greenport ' facility, implementation of the optimization methods is not neces- sary. Under the recommended scavenger waste treatment alternative, the Greenport STP will be upgraded to handle the additional waste ' loading from the scavenger waste. ' 6.1.2 Land Use Controls It is recommended that land use regulations be utilized to ' control point and non -point sources of pollution throughout the ' study area. The County of Suffolk has already established regu- lations requiring new developments expected to generate over ' 30,000 gallons of wastewater per day to provide acceptable treat- ment prior to discharge. The Town and Village should see that ' this regulation is enforced within their jurisdiction. They should ' also establish an appropriate regulatory program which can regulate the location, modification or construction of any facility (in- dustrial, commercial or residential) within the study area that may result in an adverse impact on the environment. The munici- palities must be able to control the development of the study area, ' such that no direct, adverse impact is placed on the groundwater aquifer. 1 6.2 1 1 L 1 HOLZMACHER, McLENDON and MURRELL. P.C. ' H2M CORP. 6.1.3 Fertilizer Control With fertilizers estimated to contribute the major portion of the nitrogen leaching to the groundwater within the Town of Southold, it is recommended that efforts be made to minimize the nitrogen input to the groundwater. Quantities of fertilizers applied to household lawns are expected to increase nearly four fold in the next twenty years. The Town should, therefore, man- date the use of slow release organic fertilizers through the implementation of ordinances prohibiting the sale and use of other fertilizers within the Town. Related to lawn fertilization is the problem of grass clip- ping disposal. Many homeowners presently do not remove the clippings when cutting the lawn. It is recommended that the Town encourage individual composting to provide for volatili- zation of ammonia (form of nitrogen) from the clippings. Pro- viding public awareness through informational meetings and literature should encourage individual implementation of com- posting techniques. Agricultural fertilization in Southold has been cited as contributing the bulk of nitrogen entering the groundwater through leaching. Experimental fertilizer management field studies, conducted by Cornell Cooperative Extension, have found that the nitrogen input to the groundwater can be reduced with- out decreasing the crop yield by varying the timing of applica- tion. Public information meetings should be arranged and at- tended by the farming sector and representatives of Cornell Cooperative Extension, in order to discuss these findings• 6.3 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. 6.1.4 __Water Supply Management Flan IIt is imperative that the groundwater/surface water quality ' of the study area be maintained and improved where possible. An integral part of this plan is a comprehensive groundwater/surface ' water monitoring program. Trends in regional and local ground- water quality will be determined, based on the monitoring system. Areas indicating a deterioration in quality will be acted upon ' by implementing the necessary management controls. Observation wells should be located in areas of unsewered, ' high density, residential land use, such as within Mattituck, agricultural areas, and areas where the land use is expected ' to change in the future to a more dense residential land use. ' Nitrogen should be utilized as the key pollutant parameter, because of its presence in sources such as domestic sewage and ' fertilizers. Results of a monitoring program can be the guide- lines for delineating areas requiring structural corrective ' measures. ' Pesticide testing should also be conducted periodically within the monitoring program to determine if excessive amounts ' of toxic chemicals are accumulating within the soil and ground- water. Early detection of such conditions can minimize the ad- verse impact of such chemicals through prohibiting the use of ' specified pesticides. In addition to monitoring, other techniques to be incor- porated are: a. Increase control over irrigation practices. 1 6.4 HOLZMACHER, MCLENOON and MURRELL, P C. ! H2M CORP. ' b. Increase the quantity of recharge. C. Implementation of conservation techniques. 6.1.5 Septic Tank Management Plan ' Implementation of a Septic Tank Management Plan (STMP) will ensure the proper functioning of on-site waste disposal ' systems. Provisions should be made for routine pumping (once ' every three years) and maintenance of on-site systems, in order to extend the service life of the leaching facility and ' to ensure its continued efficiency. The Town will maintain and operate a scavenger waste treatment and disposal facility. As part of the STMP, regulations are recommended to pro- hibit the use of certain chemicals utilized for cleaning or extending the service life of on-site systems. A program to ' identify such products is presently being conducted by Suffolk County. The Town should adopt and enforce a policy banning these products or enforce the County ban once it becomes law. 6.1.6 Alternative On -Site Sewage Disposal Methods After reviewing the various alternative on-site disposal ' methods, it seems unlikely to implement any major modifications ' to existing septic systems. At this time, implementation of any viable alternative would not be cost effective. The Town ' should, however, continue to consult the Suffolk County De- partment of Health Services for updated results as to the treatment improvement experiments of conventional septic sys- I toms. 1 6.5 HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. ' Sewage Disposal Plans for new developments (residential, commercial and industrial) should be examined by the Town for ' the suitability of the soil and groundwater elevation for con- ventional septic systems. The mound system should be employed ' in areas of high groundwater to allow for sufficient percolation prior to wastewater entering the groundwater. ' Literature should be provided to the public on the com- posting toilet and alternative toilet facilities. However, due to the lack of public acceptance in various areas throughout the United States, it is unlikely that these systems will have any major beneficial impact. 6.2 Structural Alternatives In addition to the non-structural alternatives recommended in Section 6.1, structural alternatives are required in order to effectively treat and dispose of scavenger u aste generated ' within the study area. We have also recommended that those densely -developed areas in the vicinity of Greenport be incor- porated by expanding the current sanitary collection system. The following sections briefly describe the recommended struc- tural alternatives to be implemented within the study area. 6.2.1 Expansion of Inc. Village of Greenport Collection System The small communities of Sterling Basin, Pipes Cove, Conk - ling Point and North Greenport have all shown a need for sewer- , ing, due to high residential development and being located in environmentally sensitive areas, as previously discussed. Being 1 6.6 HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. in close proximity to the existing Greenport collection system, ' the most cost-effective method of treatment is to transport the sewage to the existing sewage treatment plant. Excess capacity ' is available at the plant to handle both the future needs of the ' existing collection district, plus the aforementioned expanded areas. The estimated cost for construction of pump stations, ' force mains, laterals and gravity sewer is $3,313,000. Amortized over 20 years at 7-1/8 percent interest, this results in an annual capital cost of $315,000. Based on estimated annual operation and maintenance costs of $15,000., the total annual cost is estimated at $330,800. ' 6.2.2 SewerinQ of the Mattituck Area At this time, the Mattituck area does not indicate a need for sewering. However, examination of both future land use and the configuration of Mattituck Creek indicates the strong possi- bility of sewering in the future. Residential development along ' Mattituck Creek, in conjunction with a lack of tidal flushing ' within the surface water body, dictates probable contamination in the future. As part of our non-structural recommendations, ' the groundwater and surface water monitoring program will ob- serve patterns of pollution within the Mattituck area and deter- mine if on-site disposal systems are a major source of contami- nation. With the high probability of on-site systems adversely af- fecting the environment, we analyzed various treatment alterna- tives for the Matticuck area. A cost-effective analysis selected 1 6.7 HOLZMACHER. McLENDON and MURRELL, P.C. / H2M CORP. ' Alternative C -3a to be the most appropriate process for providing treatment for this area. The extended aeration, activated sludge tplant would be designed to treat up to 0.50 m.g.d., with a Sound ' or Bay outfall to discharge the treated effluent. The sludge train would entail gravity thickening, anaerobic digestion and ' dewatering, utilizing sludge drying beds. Ultimate disposal of the sludge will be handled off-site with the Greenport sludge. Implementation of this alternative is estimated to cost ' $1,881,000, excluding the cost of sanitary sewers and laterals. Based on 7-1/8 percent interest and amortized over 20 years, the I annual capital cost is $179,300. Utilizing an estimated annual operation and maintenance cost of $54,000., the total annual cost Iis estimated at $235,300. 6.2.3 Scavenger Waste Treatment and Disposal The present scavenger waste disposal method of utilizing ' leaching lagoons has been classified by New York State Depart- ment of Environmental Conservation as being environmentally un- acceptable. NYSDEC has mandated the Town of Southold to find ' alternate means of disposal. The Facility Plan has evaluated various treatment processes, including combined treatment with ' the Greenport Sewage Treatment Plant. As a result of the cost- effective analysis and screening process, Alternative SW -6 is recommended as the most applicable treatment process for treat- ing and disposing of scavenger waste. This alternative utilizes a separate pre-treatment process for scavenger waste prior to 1 6.8 IHOLZMACHER. McLENDON and MURRELL. P.C. i H2M CORP. combining with the Greenport STP wastewater flow. Unit pro- cesses of screening, degritting and primary settling will pre- treat the scavenger waste before it flows to a Rotating Biolo- gical Disc, where the BOD -5 concentration can be reduced to ' that of a typical wastewater (250 mg/l BOD -5). The scavenger ' waste will then be bled into the main wastewater stream at the head end of the Greenport plant. The existing STP will be up- graded with the addition of an effluent polishing process, such as a sand filter. Effluent will continue to be discharged through the existing outfall. The recommended sludge train ' will include anaerobic digestion, additional sludge drying beds (covered) and ultimate disposal, as discussed in the following ' subsection (6.2.4). Since the cost-effective analysis justifies a cost savings to the Town of Southold, as well as the Town of Shelter Island, ' it is recommended that the Towns negotiate an agreement for im- plementation of the recommended alternative in providing treat ' ment and disposal of scavenger waste. The estimated capital cost for scavenger waste treatment ' and disposal is $1,669,000. This cost amortized over 20 years at 7-1/8 percent interest, results in annual capital costs of ' $159,100. Annual operation and maintenance costs are estimated at $54,100. The resultant total annual cost is estimated at $213,200. Based on 87.5 percent Federal and New York State ' funding, the costs to Southold and Shelter Island are: 1 6.9 HOLZMACHER. McLENDON and MURRELL, P.C. i H2M CORP. Amortized Operation & Total ^' Town Ca2ital Costs* Maintenance Casts** Annual Costs Southold $17,600. $47,879. $65,479. Shelter Is. 2,288. 6,221. 8,509. ' Total Towns $19,888. $54,100. $73,988. * I,,ocal share based on 12.5% **Local share based on 100% 6.2.4 Ultimate Sludge Disposal ' Dewatered sludge from the existing sewage treatment plant in ' Greenport and any other plant that is to be constructed in the future (i.e, Mattituck) has been recommended to be ultimately ' disposed of at an environmentally secure landfill. Current prac- tices of landfill disposal utilizing the open pit method will be- come unacceptable in the near future. We have estimated the in- cremental costs of utlimate sludge disposal based on utilizing a portion of a sanitary landfill which will be constructed to ' conform with Part 360 requirements (i.e., double liner, leachate and methane collection). ' This alternative ultimate sludge disposal method is sub- ject to Southold's plans with regard to solid waste management. If a solid waste disposal plan is selected that also has the ' capabilities of providing sludge disposal, a cost-effective analysis will have to be prepared to compare co -disposal of ' solid waste with sludge versus sanitary landfilling of sludge. ' The estimated capital cost of this ultimate sludge dis- posal alternative is $178,000. Amortized over 20 years at 7-1/8 1 6.10 HOLZMACHER, McLENDON and MURRELL, P.C. i H2M CORP. 1 ' percent interest, this cost results in an annual capital cost of $16,900. The total annual costs are $31,900. based on an ' operation and maintenance cost of $15,000/year. e. Implementation recommendations Respectfully submitted, HOLZMACHER, McLENDON & MURRELL, P.C. Gary "E. Loesch, P.E. ' Project Manager o. A&.4 Dennis M. Kelleher Project Engineer The final document of the facility plan, entitled, "Selected Plan" will proceed based on the aforementioned recommendations and ' comments received from the Inc. Village of Greenport, Towns of Southold and Shelter Island, Suffolk County Department of Health ' Services, New York State Department of Environmental Conservation, and the United States Environmental Protection Agency. The Selected Plan will include: ' a. Preliminary design b. Capital costs 'C. Operation and maintenance costs ' d. Environmental assessment e. Implementation recommendations Respectfully submitted, HOLZMACHER, McLENDON & MURRELL, P.C. Gary "E. Loesch, P.E. ' Project Manager o. A&.4 Dennis M. Kelleher Project Engineer HOLZMACHER, McLENDON and MURRELL, P.C. / H2M CORP. LIST OF REFERENCES - LITERATURE SEARCH (1) Alternatives for Small Wastewater Treatment Systems, EPA Technology Transfer Seminar Publication EPA -625/4-77-011. (2) Eckenfelder & O'Connor, Report on Scavenger Wastes for the Town of Oyster Bay, "Biological Treatment of Septic Tank Wastes". (3) Baffa, John J., Consulting Engineers, Report on Scavenger Wastes, Town of Brookhaven. (4) Holzmacher, McLendon & Murrell, Consulting Engineers, Engineering Report, Town of Smithtown, "Scavenger Waste", June 1970. (5) Eckenfelder & O'Connor, Consultants, "Biological Treat- ment of Septic Tank Wastes, Town of Oyster Bay", Decem- ber 1960. (6) Lockwood, Kessler & Bartlett, Inc., Consulting Engineers, Engineering Report, "Sanitary Landfill Disposal of Refuse and Sanitary Disposal of Septic Tank Sludge", Town of East Hampton, September 1961, May 1962. (7) Standards for Sewage and Waste Disposal Systems. Design of Residential Subsurface Sewage Disposal Facilities by Suffolk County Department of Health Services, Division of Public Health. The Bureau of Environmental Health Services, February 1972. (8) Small, Maxwell M., BNL 50630 Natural Sewage Recycling Systems, Brookhaven National Laboratory, January 1977. (9) Kolega, J.J. et al., Anaerobic -Aerobic Treatment of Septage, Department of Agricultural Engineering at the University of Connecticut, Storrs, Conn., 1973. (10) Holzmacher, McLendon & Murrell, P.C., Consulting Engi- neers, Engineering Report and Study, Town of Riverhead and Southampton, "Scavenger Waste in Riverhead and Southampton", June 1979.