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One project that exemplifies how green remediation works and what the benefits are is the Lawrence Aviation Industries Superfund site in Port Jefferson Station, New York, a 126-acre site that is a former titanium sheeting manufacturing facility near Long Island Sound. From 1980 through 2005, cleanup efforts included removal of more than 1,300 leaking drums and containers storing a variety of chemicals and wastes, including trichloroethylene, tetrachloroethylene, acids, sludges, and hydraulic oils.
The EPA then decided to implement green practices to accomplish remediation of groundwater and soil contaminated with volatile organic compounds (VOCs) and polychlorinated biphenyls (PCBs) at the site and downgradient of the site where they had migrated. The plan involved removal and disposal of contaminated soils followed by air-stripping of groundwater both on-site to treat the contaminant source and off-site to handle a contaminant plume.
The green remediation strategies and benefits included both common sense and innovative thinking, and provide a sound basis for others to follow. For example, to maximize material reuse and reduce project costs and landfilled materials, the EPA sought local sources of equipment to be repurposed for the groundwater treatment systems. The result of their efforts included:
- Reconditioned and refabricated equipment that met most requirements of one treatment plant,
- An air stripper that was provided by a local dry cleaner, and
- Two aqueous phase carbon vessels, a vapor phase carbon vessel, bag filters, a blower device, piping, valves, connectors, pumps, electrical wiring, and interior light fixtures provided by a nearby manufacturer.
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Other strategies were used to both save and provide energy for the cleanup. To start, heat loss was minimized by installing steel vertical wells and thermally fusing all the pipe connections. A full well seal was assured by packing each one with 20 percent bentonite slurry along its full length, which was 250 feet below ground surface at the on-site facility and 80 to 140 feet below ground surface at the downgradient facility. The wells were connected to a single header assembly directing water to a single 1.5-ton geothermal heat exchange unit operating in the open-loop treatment system, and transferred to the treatment buildings’ ductwork, providing both heating and cooling as needed.
Groundwater is also pumped from the heat exchanger to the air stripping system that uses reactivated carbon, rather than virgin carbon, to treat air before its emission from the plant. To minimize the potential for inefficiencies from plugging in discharge piping, water is sent from the air stripping system to bag filters where solids are extracted.
By incorporating geothermal energy in the cleanup process, the two facilities each avoid using 6,000 to 7,000 kWh of grid-supplied electricity annually. In dollars, this translates to about $1,300 to $1,700 in annual operation and maintenance costs. Equally important is that the system offsets an estimated 4.1 to 4.8 metric tons of carbon dioxide (equivalent) emissions at the same time.
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At the on-site facility, the fully processed water is returned to the underlying aquifer through a network of five 258-foot injection wells approximately 1,000 feet upgradient from the extraction wells. At the downgradient facility, the fully processed water is sent to a nearby existing pond and its adjoining creek rather than to the sewer system.
Other notable accomplishments include using pervious pavement in the parking areas and providing 240 tons of uncontaminated soil excavated for the pavement to the highway department. Landscaping included replacing invasive/nonnative species with native species of plants, using trees removed during construction for mulched areas, and incorporating a variety of LEED green building practices during treatment building design and construction.
When remediation goals are met and the treatment system is decommissioned, the off-site property will be used by the local municipal parks department as a field office and concession facility for an adjacent park.