Opportunity
Beginning in 1963, a family-owned municipal landfill served the residents of Plattekill, New York, a farming community in Ulster County known for its hunting, fishing, and apple orchards. Around 1970, a Dutchess County company began transporting waste there, and in 1975 the company bought the facility.
In 1976, the Ulster County Department of Health and New York State Department of Law revoked the Hertel Landfill’s permit, citing violations that included allegations of illegal industrial dumping. The landfill was permanently closed in 1977, and in 1981 five groundwater monitoring wells were installed.
A 1985 site inspection found “exposed wastes, stained soils, industrial-type odors and multi-colored seepage entering the adjacent wetlands.” Since all local drinking water comes from private wells, residents were concerned about contamination of groundwater and of Black Creek, which flows past a high school three miles downstream.
Solution
Based on the results of the monitoring, the Hertel Landfill was designated a Superfund site in 1986. In 1990, the US EPA completed a Remedial Investigation/Feasibility Study, providing the basis for a Record of Decision (ROD). The ROD recommended that the landfill be capped and that groundwater be recovered and treated by ultraviolet oxidation with membrane microfiltration.
Mott MacDonald was selected in 1996 by the Hertel Steering Committee to conduct a remedial investigation that would assess the recommendations of the ROD. We designed a revised remediation plan that included reconsolidation of waste, offsite disposal of buried drums, regrading of landfill areas, and installation of a methane venting system, leachate collection system, and a permanent cap.
Mott MacDonald later analyzed local supplies of potable water and modeled the extent of groundwater contamination in two aquifer units that covered 16 square miles (41 square kilometers). The study showed that the groundwater extraction and treatment program would have a negative impact on local wetlands, and that the cap and leachate collection system as installed had reduced the migration of contaminants.
In 2005, finding that existing remediation efforts were effective, the EPA amended the ROD to include a long-term monitoring program and eliminate the proposed groundwater extraction and treatment program.
Outcome
Our analysis helped avoid the unnecessary expense and negative impact on wetlands of recovering and treating local groundwater. Estimated savings were $800,000 in capital expenditures and 30 years of operation and maintenance costs totaling $7 million.
We continue to ensure the quality of the local environment by monitoring air, surface water, sediment, and groundwater, as well as maintaining the protective cap on the landfill.