The Army Creek Landfill site, a former sand and gravel quarry, is approximately two miles southwest of New Castle, Delaware. The site abuts Army Creek/Pond and high quality wetlands to the south and east and lies adjacent to Delaware Sand and Gravel Landfill, another Superfund site. From 1960 to 1968, when the landfill reached capacity and closed. A 1986 Record of Decision (ROD) provided for capping of the landfill and for the continued operation of the recovery well network to maintain the ground water divide. The extracted ground water currently discharged into Army Creek Pond untreated. The selected remedial action for the site includes ground water pumping using the recovery well network and treatment using a modified conventional precipitation water treatment plant which involves aeration, precipitation, sedimentation, and filtration followed by onsite discharge of the effluent to Army Creek/Pond; sampling and disposal of sludge generated during the treatment process; and monitoring of the sediment, recovered ground water, surface water, and wetlands. The estimated present worth cost for the remedial action is $4,900,000 which includes an annual O and M cost of $294,000.