Site Name: ISLIP MUNICIPAL SANITARY LANDFILL
EPA ID: NYD980506901 EPA Region: 02 Metro Statistical Area: 5380
BLYDENBURG RD/LG ISLAND MOTOR, HAUPPAUGE, NY 11751
Operable Unit: 01
ROD ID: EPA/ROD/R02-92/183 ROD Date: 09/30/92
Contaminant: VOCs, Other Organics, Metals
Keys: Aeration; Air Monitoring; Arsenic; Benzene; Capping; Carbon Adsorption (GA); Carcinogenic Compounds; Chromium; Clean Air Act; Clean Water Act; Contingent Remedy; Direct Contact; Ground Water; Ground Water Monitoring; Ground Water Treatment; Institutional Controls; Landfill Closure; Lead; MCLs; Metals; O&M; Onsite Containment; Onsite Disposal; Onsite Treatment; Organics; PCE; RCRA; Safe Drinking Water Act; Soil; Solvents; Collection/Diversion; TCE; Toluene; Treatability Studies; VOCS.
Abstract:
SITE HISTORY/DESCRIPTION: The 107.5-acre Islip Municipal Sanitary Landfill site is located in Hauppauge, Town of Islip, Suffolk County, New York. Land use in the surrounding area is predominantly residential, with a day care center and an apartment complex located adjacent to the northern edge of the landfill. The Glacial and Magothy aquifers underlying the site are a primary source of potable water in the region, and five public supply wells are located within a 2-mile radius of the site. Two perennial surface water bodies, the Connetquot Brook and the North Branch of the Nissequogue River, are located nearby and are used for recreational purposes. From 1963 to 1990, the site was operated as a municipal landfill; an incinerator, which was constructed onsite, operated from 1963 to 1968. Landfilling activities have occurred in phases. Encompassing 55.4 acres, Phase I (unlined area) and Phase II (lined area) of the landfill received waste from the early 1960's through the early 1980's. It is believed that in 1978, sixty to seventy 55-gallon drums of waste dry-cleaning solvent were disposed of in these areas. The 13.4 acres planned for Phase III will be used for disposal of clean fill, and the remainder of the property is used for temporary storage of ash fill, sand storage and borrow areas, setback/buffer zones, vehicle storage, and other support uses. In 1979, the Town purchased two houses adjacent to the site because of high concentrations of methane detected in their basements. An active gas-collection system was installed to control migration of explosive gases beyond the site boundary. Ground water investigations, which were conducted in 1980, revealed VOC contamination in private wells. Public water mains or alternative water supplies were extended to affected residents. During 1987, the unlined area was capped, and a liner/leachate collection system was installed over the cell for vertical expansion of landfilling operations. In 1990, the state required the site to stop receiving municipal waste and begin implementing a complete closure program of the entire landfilled area. This ROD addresses a final remedy for the contaminated soil, debris, and ground water at the site. The primary contaminants of concern affecting the soil, debris, and ground water are VOCs, including benzene, PCE, TCE, and toluene; other organics; and metals, including arsenic, chromium, and lead. PERFORMANCE STANDARDS OR GOALS: Chemical-specific ground water clean-up goals, which are based on SDWA MCLs and state standards, include benzene 5 ug/l (MCL); PCE 5 ug/l (MCL); TCE 5 ug/l (MCL); toluene 5 ug/l (MCL); arsenic 0.025 mg/l (state); chromium 50 ug/l; and lead 0.02 mg/l (state). INSTITUTIONAL CONTROLS: This remedy includes recommendations that deed and well restrictions be imposed to prevent the installation of drinking water wells in impacted areas.
Remedy:
SELECTED REMEDIAL ACTION: The selected remedial action for this site includes installing a modified geosynthetic membrane cap over 52 acres of the landfill; constructing a stormwater system to direct and control runoff from the site to recharge basins; allowing ground water with total VOC concentrations less than 50 ug/l to naturally attenuate; extracting and onsite treatment of ground water with total VOC concentrations greater than 50 ug/l using aeration, with discharge of the treated water onsite to a recharge basin; determining if carbon absorption will be required as a polishing treatment step to ensure compliance with state discharge limits; conducting a treatability study to determine the effectiveness of aeration in precipitating metals from the ground water, and providing for a contingency remedy that treats ground water using chemical precipitation and air stripping; evaluating the ground water treatment system to determine whether an air pollution control device is necessary; monitoring ground water and air; and implementing institutional controls including deed and ground water restrictions to prevent the installation of drinking water wells in impacted areas. The estimated present worth cost for this remedial action is $17,942,025, which includes a present worth O&M cost of $4,588,875 for 30 years.