Appendix D
Analysis of Wastewater Treatment Plants and On-site Sewage Treatment and Disposal Systems: The Impact Index

This appendix describes the methods used creating the Impact Index found in Chapter 11. The Impact Index shows the relative pollutant loadings of wastewater treatment plants (WWTPs) and on-site sewage treatment and disposal systems (OSTDS) in individual reservoir basins. For each West-of-Hudson reservoir, Kensico Reservoir, and West Branch Reservoir, a worksheet similar to the one presented below was created. An explanation of each worksheet entry is given below, followed by the eight worksheets completed for each reservoir.

Impact Index Worksheet

Known Permanent Watershed Population1

Permitted Number of Sewage Treatment Plants2

Permitted Wastewater flow from WWTPs3

Discharger

Daily Flow

Parameter

Input from WWTPs Now4

Input w/upgrades5

Input 2010 w/growth6

Phosphorus (lbs/day)

 

 

 

Giardia Cysts (106/day)

 

 

 

Fecal Coliforms (106/day)

 

 

 

Viruses (106/day)

 

 

 

Total Suspended Solids (lbs/day)

 

 

 

Cryptosporidium Oocysts (106/day)

 

 

 



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Watershed Management for Potable Water Supply: Assessing the New York City Strategy Appendix D Analysis of Wastewater Treatment Plants and On-site Sewage Treatment and Disposal Systems: The Impact Index This appendix describes the methods used creating the Impact Index found in Chapter 11. The Impact Index shows the relative pollutant loadings of wastewater treatment plants (WWTPs) and on-site sewage treatment and disposal systems (OSTDS) in individual reservoir basins. For each West-of-Hudson reservoir, Kensico Reservoir, and West Branch Reservoir, a worksheet similar to the one presented below was created. An explanation of each worksheet entry is given below, followed by the eight worksheets completed for each reservoir. Impact Index Worksheet Known Permanent Watershed Population1 Permitted Number of Sewage Treatment Plants2 Permitted Wastewater flow from WWTPs3 Discharger Daily Flow Parameter Input from WWTPs Now4 Input w/upgrades5 Input 2010 w/growth6 Phosphorus (lbs/day)       Giardia Cysts (106/day)       Fecal Coliforms (106/day)       Viruses (106/day)       Total Suspended Solids (lbs/day)       Cryptosporidium Oocysts (106/day)      

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Watershed Management for Potable Water Supply: Assessing the New York City Strategy Known Number of OSTDS7 Estimated Wastewater flow from OSTDS8 Estimated Percent of Population served by OSTDS9 Estimated Population served by OSTDS (@2.5 persons/home)10 Parameter Input from OSTDS Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 11 17 23 Giardia Cysts (106/day) 12 18 24 Fecal Coliforms (106/day) 13 19 25 Viruses (106/day) 14 20 26 Total Suspended Solids (lbs/day) 15 21 27 Cryptosporidium Oocysts (106/day) 16 22 28 Notes 1.   Population from NYC DEP (1993), and based on 1990 Census values. 2.   Permitted number of WWTPs from Table 5-4. 3.   Permitted flow from WWTPs from Table 5-4. 4.   Obtained from NYC DEP (1993 EIS), Table NC-2 "Existing, Expanded and New WWTPs Summary of No Action/Action Impact on Pollutant Loadings by District and Drainage Basin Totals." 5.   Obtained from NYC DEP (1993 EIS), Table NC-2 "Existing, Expanded and New WWTPs Summary of No Action/Action Impact on Pollutant Loadings by District and Drainage Basin Totals." 6.   Calculated by applying the growth rate observed for the period 1990 to 1996 to the period from 1990 to 2010. The observed annual growth rate of 0.25 percent for the West-of-Hudson basin resulted in a total population increase of 5 percent in 2010. The observed annual growth rate of 1.06 percent for the East-of-Hudson basin resulted in a total population increase of 21.2 percent for the Kensico and West Branch basins in 2010. 7.   Septic system numbers from NYC DEP (1993, Table VIII F-3). 8.   Based on 50 gallons of wastewater per day per person (Chanlett, 1979). 9.   Derived by dividing the estimated population served by OSTDS (#10) by the known permanent watershed population (#1). Values slightly exceeding 100 percent appears to reflect the fact that many of the WWTPs serve schools and not residential subdivisions, while values greatly exceeding 100 percent may be attributable to large numbers of seasonal residences. 10.   Calculated by multiplying the known number of OSTDS (#7) by 2.5 residents. This assumes that there is one OSTDS per residence, 2.5 occupants per residence, and that only residences (not commercial facilities) are served by OSTDS. 2.5 occupants per household is the figure for Florida derived from the 1990 Census values for population (12,937,926) divided by the number of households (5,138,360). 11.   This is the average value for total phosphorus (0.0082 lb/day) found in effluent from conventional septic tank and drainfield systems as reported by Ayres (1993). It has been multiplied by the estimated population served by OSTDS (#10). 12.   Assumes 6.4 percent of the population using OSTDS (#10) is positive for Giardia. This is based on the average of two CDC studies of prevalence of parasites in stool specimens which reported Giardia was found in 7.2 percent of samples examined in 1987 and 5.6 percent of samples examined in 1991 (Kappus et al., 1994). The number of positive residents is then multiplied by the maximum number of Giardia cysts excreted per day by an individual (9 × 106 cysts reported by Knight, 1980). This has been multiplied by 0.05 to reflect reported failure rates (defined as surfacing sewage) for conventional systems. This assumes that the remaining 95 percent of the systems are functional and remove all Giardia cysts.

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Watershed Management for Potable Water Supply: Assessing the New York City Strategy 13.   This is the value for fecal coliform bacteria (2.7 MPN × 106/100mL) found in effluent from conventional septic tank and drainfield systems as reported by Canter and Knox (1986). It has been multiplied by 0.05 of the total daily flow from OSTDS (#8) to reflect reported failure rates (defined as surfacing sewage) for conventional systems. This assumes that the remaining 95 percent of the systems are functional and remove all fecal coliforms. 14.   This is the value for viruses (22 units/L) found in effluent from conventional septic tank and drainfield systems as reported by Anderson et al. (1991). It has been multiplied by 0.05 of the total daily flow from OSTDS (#8) to reflect reported failure rates (defined as surfacing sewage) for conventional systems. A similar process is applied to the remaining 95 percent of functional systems using the value for viruses (0.002 units/L) found 24 inches beneath the drainfield of conventional systems by Anderson et al. (1991). 15.   Based on negligible value for total suspended solids (mg/L) found in effluent from conventional septic tank and drainfield systems (K. Sherman, FL DOH, personal communication, 1998). 16.   Assumes 0.21 percent of the population using OSTDS (#10) is positive for Cryptosporidium. This is based on the average of two CDC studies of prevalence of parasites in stool specimens which reported Cryptosporidium was found in 0.23% of 216,275 stools examined in 1987 and 0.20 percent of 178,786 samples examined in 1991 (Kappus et al., 1994). The number of positive residents is then multiplied by the average number of Cryptosporidium oocysts excreted per day by each infected individual (1 × 107, which is the midpoint of the range found in Goodgame et al., 1993). This has been multiplied by 0.05 to reflect reported failure rates (defined as surfacing sewage) for conventional systems. This assumes that the remaining 95 percent of the systems are functional and remove all Cryptosporidium oocysts. 17.   This is the average value for total phosphorus (0.0014 lb/day) found in effluent from aerobic treatment systems as reported by Ayres (1993). It has been multiplied by the estimated population served by OSTDS (#10). 18.   This assumes that BACT (aerobic treatment unit) removes virtually all Giardia cysts and that the failure rate, with a stringent regulatory structure, would be negligible. 19.   This reflects the fact that BACT (aerobic treatment unit) removes virtually all fecal coliform bacteria and the failure rate, with a stringent regulatory structure, would be negligible. 20.   This is the value for viruses (0.002 units/L) found in effluent 24 inches beneath the drainfield of conventional septic tank and drainfield systems as reported by Anderson et al. (1991). It has been multiplied by the total daily flow from OSTDS (#8) and assumes that all systems would be functional with adequate regulatory oversight. 21.   Based on negligible value for total suspended solids (mg/L) found in effluent from BACT (aerobic treatment unit) (K. Sherman, FL DOH, personal communication, 1998). 22.   This assumes that functional BACT (aerobic treatment unit) removes virtually all Cryptosporidium oocysts and that the failure rate, with a stringent regulatory structure, would be negligible. 23.   This is the value from #17 with the growth factor described in #6 applied. 24.   This is the value from #18 with the growth factor described in #6 applied. 25.   This is the value from #19 with the growth factor described in #6 applied. 26.   This is the value from #20 with the growth factor described in #6 applied. 27.   This is the value from #21 with the growth factor described in #6 applied. 28.   This is the value from #22 with the growth factor described in #6 applied.

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Watershed Management for Potable Water Supply: Assessing the New York City Strategy RESERVOIR: Kensico Known Permanent Watershed Population 4,432 Permitted Number of Wastewater Treatment Plants 0 Permitted Wastewater flow from WWTPs (gallons/day) 0 Known Number of OSTDS 580 Estimated Wastewater flow from OSTDS (gallons/day) 29,000 Estimated Percent of Population served by OSTDS 31 Estimated Population served by OSTDS (@2.5 persons/home) 1,450 Parameter Input from OSTDS Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 11.9 2.0 2.4 Giardia Cysts (106/day) 42 0 0 Fecal Coliforms (106/day) 146,770 0 0 Viruses (106/day) 0.1 0 0 Total Suspended Solids (lbs/day) 0 0 0 Cryptosporidium Oocysts (106/day) 0.2 0 0 RESERVOIR: West Branch Known Permanent Watershed Population 3,210 Permitted Number of Wastewater Treatment Plants 1 Permitted Wastewater flow from WWTPs (gallons/day) 20,000 Discharger Daily Flow Clear Pool Camp 20,000 Parameter Input from WWTPs Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 0.8 0.2 0.3 Giardia Cysts (106/day) 13.6 13.6 16.3 Fecal Coliforms (106/day) 302.8 302.8 363.4 Viruses (106/day) 0.4 0.4 0.5 Total Suspended Solids (lbs/day) 3.3 1.7 2.0 Cryptosporidium Oocysts (106/day) 1.2 1.2 1.4

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Watershed Management for Potable Water Supply: Assessing the New York City Strategy Known Number of OSTDS 1,777 Estimated Wastewater flow from OSTDS (gallons/day) 222,125 Estimated Percent of Population served by OSTDS 138 Estimated Population served by OSTDS (@2.5 persons/home) 4,443 Parameter Input from OSTDS Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 36.5 6.1 7.3 Giardia Cysts (106/day) 128 0 0 Fecal Coliforms (106/day) 1,139,501 0 0 Viruses (106/day) 0.9 0 0 Total Suspended Solids (lbs/day) 0 0 0 Cryptosporidium Oocysts (106/day) 0.5 0 0 RESERVOIR: Ashokan Known Permanent Watershed Population 14,294 Permitted Number of Wastewater Treatment Plants 6 Permitted Wastewater flow from WWTPs (gallons/day) 605,826 Discharger Daily Flow Belleayre Mt. Ski Center 29,000 Camp Timberlake 34,000 Onteora Schools 27,000 Mountainside Rest 3,076 Pine Hill WWTP 500,000 Rotron, Inc. 12,750 Parameter Input from WWTPs Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 2.0 1.3 1.4 Giardia Cysts (106/day) 113.4 113.4 120.2 Fecal Coliforms (106/day) 1070.3 1070.3 1134.5 Viruses (106/day) 3.5 3.5 3.7 Total Suspended Solids (lbs/day) 5.3 5.3 5.6 Cryptosporidium Oocysts (106/day) 11.2 11.2 11.9 Known Number of OSTDS 5,360 Estimated Wastewater flow from OSTDS (gallons/day) 670,000 Estimated Percent of Population served by OSTDS 94 Estimated Population served by OSTDS (@2.5 persons/home) 13,400

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Watershed Management for Potable Water Supply: Assessing the New York City Strategy Parameter Input from OSTDS Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 110.0 18.3 19.4 Giardia Cysts (106/day) 386 0 0 Fecal Coliforms (106/day) 3,437,100 0 0 Viruses (106/day) 2.8 0 0 Total Suspended Solids (lbs/day) 0 0 0 Cryptosporidium Oocysts (106/day) 1.4 0 0 RESERVOIR: Schoharie Known Permanent Watershed Population 17,662 Permitted Number of Wastewater Treatment Plants 19 Permitted Wastewater flow from WWTPs (gallons/day) 1,751,113 Discharger Daily Flow Camp Loyaltown, Inc. 21,000 Colonel Chair Estates 30,000 Crystal Pond Townhouse 36,000 Elka Park 10,000 Forester Motor Lodge 3,900 Frog House Restaurant 1,788 Golden Acre Farms 9,200 Grand George WWTP 500,000 Harriman Lodge 20,000 Hunter Highlands 80,000 Latvian Church Camp 7,000 Liftside at Hunter Mountain 81,000 Mountain View Estates 13,000 Ron-De-Voo Restaurant 1,000 Snowtime 120,000 Tannersville WWTP 800,000 Thompson House Inc. 4,775 Whistle Tree Development 12,450 Parameter Input from WWTPs Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 12.7 4.5 4.8 Giardia Cysts (106/day) 536.9 299.3 317.3 Fecal Coliforms (106/day) 3,718.4 2,567.8 2,721.9 Viruses (106/day) 16.5 9.3 9.9 Total Suspended Solids (lbs/day) 29.7 10.7 11.3 Cryptosporidium Oocysts (106/day) 53.0 30.8 32.6

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Watershed Management for Potable Water Supply: Assessing the New York City Strategy Known Number of OSTDS 7,869 Estimated Wastewater flow from OSTDS (gallons/day) 98,363 Estimated Percent of Population served by OSTDS 111 Estimated Population served by OSTDS (@2.5 persons/home) 19,673 Parameter Input from OSTDS Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 161.7 26.9 28.5 Giardia Cysts (106/day) 567 0 0 Fecal Coliforms (106/day) 504,602 0 0 Viruses (106/day) 0.4 0 0 Total Suspended Solids (lbs/day) 0 0 0 Cryptosporidium Oocysts (106/day) 2.1 0 0 RESERVOIR: Cannonsville Known Permanent Watershed Population 17,000 Permitted Number of Wastewater Treatment Plants 7 Permitted Wastewater flow from WWTPs (gallons/day) 2,000,000 Discharger Daily Flow Delaware-BOCES 2,500 Delhi 515,000 SEVA Institute 7,800 Allen Center 20,000 Stamford WTP 500,000 Village of Hobart 160,000 Walton WTP 1,170,000 Parameter Input from WWTPs Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 86.6 4.3 4.6 Giardia Cysts (106/day) 69,658.6 22,847.3 24,217.8 Fecal Coliforms (106/day) 1,471.9 1,324.0 1,403.4 Viruses (106/day) 253.3 82.2 87.1 Total Suspended Solids (lbs/day) 287.3 6.3 6.7 Cryptosporidium Oocysts (106/day) 6,473.3 308.5 327

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Watershed Management for Potable Water Supply: Assessing the New York City Strategy Known Number of OSTDS 8,388 Estimated Wastewater flow from OSTDS (gallons/day) 1,048,500 Estimated Percent of Population served by OSTDS 123 Estimated Population served by OSTDS (@2.5 persons/home) 20,970 Parameter Input from OSTDS Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 172.3 28.70 30.4 Giardia Cysts (106/day) 604 0 0 Fecal Coliforms (106/day) 5,378,805 0 0 Viruses (106/day) 4.4 0 0 Total Suspended Solids (lbs/day) 0 0 0 Cryptosporidium Oocysts (106/day) 2.2 0 0 RESERVOIR: Pepacton Known Permanent Watershed Population 15,622 Permitted Number of Wastewater Treatment Plants 6 Permitted Wastewater flow from WWTPs (gallons/day) 579,400 Discharger Daily Flow Camp NuBar 12,500 Camp Tai Chi 7,500 Margaretville WWTP 400,000 Mountainside Farms, Inc. 49,800 Regis Hotel 9,600 Roxbury Run Village 100,000 Parameter Input from WWTPs Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 8.6 1.5 1.6 Giardia Cysts (106/day) 227.2 82.1 87 Fecal Coliforms (106/day) 2,396.3 407.2 431.6 Viruses (106/day) 7.0 2.6 2.8 Total Suspended Solids (lbs/day) 21.9 3.3 3.5 Cryptosporidium Oocysts (106/day) 23.5 8.9 9.4 Known Number of OSTDS 6,417 Estimated Wastewater flow from OSTDS (gallons/day) 802,150 Estimated Percent of Population served by OSTDS 103 Estimated Population served by OSTDS (@2.5 persons/home) 16,043

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Watershed Management for Potable Water Supply: Assessing the New York City Strategy Parameter Input from OSTDS Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 131.9 22.0 23.3 Giardia Cysts (106/day) 462 0 0 Fecal Coliforms (106/day) 4,115,029 0 0 Viruses (106/day) 3.4 0 0 Total Suspended Solids (lbs/day) 0 0 0 Cryptosporidium Oocysts (106/day) 1.7 0 0 RESERVOIR: Rondout Known Permanent Watershed Population 4,170 Permitted Number of Wastewater Treatment Plants 1 Permitted Wastewater flow from WWTPs (gallons/day) 180,000 Discharger Daily Flow Grahamsville WWTP 180,000 Parameter Input from WWTPs Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 0.3 0.3 0.3 Giardia Cysts (106/day) 12.7 12.7 13.5 Fecal Coliforms (106/day) 33.5 33.5 35.5 Viruses (106/day) 0.4 0.4 0.4 Total Suspended Solids (lbs/day) 0.1 0.1 0.1 Cryptosporidium Oocysts (106/day) 1.5 1.5 1.6 Known Number of OSTDS 1,414 Estimated Wastewater flow from OSTDS (gallons/day) 176,750 Estimated Percent of Population served by OSTDS 85 Estimated Population served by OSTDS (@2.5 persons/home) 3,535 Parameter Input from OSTDS Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 29.1 4.8 5.1 Giardia Cysts (106/day) 102 0 0 Fecal Coliforms (106/day) 906,728 0 0 Viruses (106/day) 0.7 0 0 Total Suspended Solids (lbs/day) 0 0 0 Cryptosporidium Oocysts (106/day) 0.4 0 0

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Watershed Management for Potable Water Supply: Assessing the New York City Strategy RESERVOIR: Neversink Known Permanent Watershed Population 1,557 Permitted Number of Wastewater Treatment Plants 0 Permitted Wastewater flow from WWTPs (gallons/day) 0 Known Number of OSTDS 822 Estimated Wastewater flow from OSTDS (gallons/day) 102,750 Estimated Percent of Population served by OSTDS 132 Estimated Population served by OSTDS (@2.5 persons/home) 2,055 Parameter Input from WWTPs Now Input w/ upgrades Input 2010 w/ growth Phosphorus (lbs/day) 16.9 2.8 3.0 Giardia Cysts (106/day) 59 0 0 Fecal Coliforms (106/day) 527,108 0 0 Viruses (106/day) 0.4 0 0 Total Suspended Solids (lbs/day) 0 0 0 Cryptosporidium Oocysts (106/day) 0.2 0 0 REFERENCES Anderson, D. L., A. L. Lewis, and K. M. Sherman. 1991. Human enterovirus monitoring at on-site sewage disposal systems in Florida. Pp. 94-104 In On-Site Wastewater Treatment, Proceedings of the Sixth National Symposium on Individual and Small Community Sewage Systems. St. Joseph, MI: Amer. Soc. Ag. Engineers. Ayres, A. 1993. Onsite Sewage Disposal Systems Research in Florida: An Evaluation of Current OSDS Practices in Florida . Tallahassee: Florida Department of Health and Rehabilitative Services. Canter, L. W., and R. C. Knox. 1986. Septic Tank System Effects on Groundwater Quality. Chelsea, MI: Lewis Publishers Inc. Chanlett, E. T. 1979. Environmental Protection. New York, NY: McGraw-Hill. Goodgame, R. W., R. M. Genta, A. C. White, and C. L. Chappell. 1993. Intensity of infection in AIDS-associated cryptosporidiosis. Journal of Infectious Diseases 167:704–709. Kappus, K. D., R. G. Lundgren, Jr., D. D. Juranek, J. M. Roberts, and H. C. Spencer. 1994. Intestinal parasitism in the United States: Update on a continuing problem. Am. J. Trop. Med. Hyg. 506:705–713. Knight, R. 1980. Epidemiology and transmission of giardiasis. Transactions of the Royal Society of Tropical Medicine and Hygiene 74(4):433–435. Marx, R., and E. Goldstein. 1993. A guide to New York City's reservoirs and their watersheds. New York, NY: Natural Resource Defense Council. New York City Department of Environmental Protection (NYC DEP). 1993. Final Generic Environmental Impact Statement for the Proposed Watershed Regulations for the Protection from Contamination, Degradation, and Pollution of the New York City Water Supply and its Sources . November 1993. Corona, NY: NYC DEP.