Integrating Federal and State Requirements for Managing PCB Remediation Wastes - A Case Study at a Former MGP Site

摘要

Baltimore Gas and Electric Company's (BGE) Spring Gardens site is undergoing remediation for a historic release of PCB-contaminated oil that originally contained between 50 and 250 ppm PCBs. Extensive treatment of the co-recovered groundwater is required prior to its discharge via an NPDES-permitted outfall, because the site retains the legacy from over 100 years of manufactured (coal) gas production. The groundwater treatment system produces separated oil and several process treatment residuals. Prior to the U.S. EPA's June 1998 PCB MEGA Rule, all process residuals had to be managed based upon the PCB concentration of the original PCB source (oils). In addition, Maryland's hazardous waste regulations required that the oils and process residuals that were mixed with, or derived from, the PCB-contaminated oils had to be managed as a state hazardous waste. BGE observed, during early stages of the recovery system trials, that PCBs were not present in the process residuals, but were being segregated in the recovered oils. We realized that managing some or all of the process treatment residuals as non-PCB, non-hazardous waste could significantly reduce disposal costs. Therefore, we initiated a program in mid-1997 to obtain variances for the process residuals from TSCA and State hazardous waste regulation, realizing that separate approvals were required from both U.S. EPA's Region III and Maryland's Department of the Environment. An extensive sampling and analysis program performed at key points throughout the treatment process documented and confirmed our hypothesis that PCBs exited the system in the recovered oil and that no dilution or degradation of the PCBs was occurring. The new definition and disposal requirements for "PCB remediation waste" in EPA's MEGA Rule enabled BGE to obtain a clarification from EPA Region III, that the process residuals and recovered oil could be managed based upon their "as generated" PCB concentration, rather than based upon the PCBs in the originally-released oils. Subsequently, we were able to use the same data to obtain a similar clarification from Maryland's Department of the Environment regarding the non-hazardous status of the process residuals.