In 1999, Roux Associates, on behalf of BASF Corporation, developed andimplemented an integrated, sustainable and innovative system to replace an aging,conventional wastewater treatment plant (WWTP) at a former manufacturing facility inVirginia. The integrated treatment system consists of a constructed treatment wetland(CTW) that utilizes biologically-mediated processes to treat leachate generated from adecommissioned landfill, and 18.5 acres of adjacent phytotechnology plantings to reduceleachate generation, consume effluent from the CTW and mitigate stormwater runoff tothe CTW. This passive, gravity flow CTW system provides BASF with a sustainable,cost-effective, low operation and maintenance (O&M) alternative to conventionaltreatment.The former BASF Fibers Plant in James City County, Virginia, contains a 32-acre decommissionedlandfill within a 60-acre drainage area in the south-central section of theproperty. Historically, leachate and stormwater runoff from the landfill area was collectedwithin a 16-acre man-made marsh termed the dredge spoils area (DSA) and pumped to anon-site WWTP prior to discharge to a permitted surface water outfall. The principal constituentsof concern are acidity, zinc and iron.To facilitate decommissioning of the on-site WWTP and closure of the existing solidwaste landfill, a full-scale CTW system was retrofitted into the existing DSA impoundmentto provide pretreatment of stormwater and leachate prior to discharge to a localPOTW. The CTW system consists of an engineered sequence of aerobic and anaerobictreatment units and utilizes the mechanisms of anaerobic bicarbonate production, settlement/aeration and sulfate reduction to mitigate pH, iron and zinc. The system has operatedsuccessfully since 2000 and has undergone several enhancements, including:· Treatment unit enhancements to optimize the system hydraulics, address challengesassociated with extreme weather events (I.e., hurricanes) and optimize biologically-mediated treatment processes within the system;· Collection/conveyance modifications to increase pumping capacity to the POTWfrom 50,000 gallons per day (gpd) up to 300,000 gpd; and· Installation of an 18.5-acre phytotechnology plot on the landfill surface using approximately17,000 hybrid poplar trees to reduce leachate generation and mitigatestormwater runoff.This presentation offers an overview of the landfill and surrounding drainage area waterbalance and the application of CTW/Phytotechnologies to provide a sustainable and integratedsite water management strategy for leachate minimization and treatment. Specific
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