A RCRA CLEAN CLOSURE CERTIFICATION FOR NORTHEAST ELECTRONICS CORPORATION

Working on behalf of the Northeast Electronics Corporation (NEC), LBG was successful in obtaining Resource Conservation and Recovery Act (RCRA) Clean Closure Certification, including a release from financial assurances, for two surface impoundments in Milford, Connecticut.

NEC manufactures electronic components. In 1981, the company used two surface impoundments on its property to dry approximately 4,500 pounds of metal hydroxide sludge. In 1982, the sludge was removed from the impoundments and disposed of in accordance with all applicable hazardous waste regulations. Because the sludge was classified as a hazardous waste under RCRA, NEC was required to either permit the impoundments or close them. NEC no longer needed the impoundments, so it chose to close them.

LBG designed and implemented a ground-water monitoring program to determine if the impoundments had impacted ground water. As a result of the monitoring, Trichloroethylene (TCE) and Perchloroethylene (PCE) were detected above drinking water standards; however, none of the known sludge constituents were found.

To be granted clean closure, NEC needed to prove that the surface impoundments were not the source of the TCE and PCE.

If the company could not demonstrate this, the impoundments would have to be closed as a landfill, which would require capping as well as 30 years of post closure monitoring, a deed restriction and financial assurances.

To make the demonstration, LBG conducted a comprehensive soil and ground-water investigation involving soil sampling in and around the impoundments, the installation of additional upgradient and downgradient monitor wells, ground-water sampling and geophysical surveys. The results of the investigation showed that the impoundments were not the source of the TCE and PCE in the ground water.

To achieve clean closure, all residually contaminated soil from the impoundments was excavated and soil analyses conducted to show that the remaining soil met health-based exposure limits. Additionally, a soil-gas survey was initiated to locate the source of TCE and PCE in the ground water.

Soil containing high levels of PCE and TCE was located under the floor of a storage building directly upgradient of the surface impoundments. Once this was determined, NEC was granted clean closure by the CTDEP and the U.S. Environmental Protection Agency, including a release from financial assurances and ground-water monitoring requirements.