The U.S. Environmental Protection Agency has finalized an Administrative Settlement Agreement and Order on Consent (Settlement) directing Bridgeton Landfill to start work on several critical components of the isolation barrier system in the North Quarry portion of the West Lake Landfill Site. In December 2015, EPA announced its decision to require the construction of an isolation barrier system.  The Enforcement Action Memorandum that accompanies the Settlement outlines the first steps in the implementation of that decision. “EPA has valued the state of Missouri’s efforts to manage their portion of the site,” said EPA Region 7 Administrator Mark Hague.  “We believe this Settlement will initiate needed actions in the North Quarry while the state continues its efforts to require Bridgeton Landfill to address the ongoing subsurface reaction.”

The actions required by the Settlement include installation of a Heat Extraction System in the “neck” portion of the Bridgeton Landfill, development of an inert gas injection system, and installation of an ethylene vinyl alcohol copolymer (EVOH) cover over the North Quarry portion of the Bridgeton Landfill. The Settlement also requires the installation of two sulfur dioxide (SO2) air monitors and installation of additional North Quarry Subsurface Temperature Monitoring Probes (TMPs).  The TMPs will monitor landfill temperatures that could be a precursor to, or indicative of, a subsurface reaction in the North Quarry. Pursuant to the terms of the Settlement, Bridgeton Landfill is required to submit work plans for the Heat Extraction System, inert gas injection, TMPs and SO2 monitors within 30 days.  Bridgeton Landfill is also required to submit work plans for the EVOH cover within 60 days.  The Settlement further requires completion of the Heat Extraction System in the “neck” within four months of the construction start date.

EPA is working in close coordination with the Missouri Department of Natural Resources, which remains the lead agency for oversight of the Bridgeton Landfill, or Operable Unit 2 of the West Lake Landfill Site. EPA continues to work on the technical and legal details of the remaining portions of the isolation barrier system, and will provide these details to the public when they are available.

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