Phased Approach for Determining the Presence of Radionuclides in Municipal Wastewater Treatment Plant Residuals

The presence of radioactive materials in biosolids—from both natural and industrial sources—has received increased attention in recent years. In the summer of 1994, Congressional hearings were held in response to a General Accounting Office Study, Action Needed to Control Radioactive Contamination at Sewage Treatment Plants (GAO/RCED-94-133). This report identified inadequacies in the regulation of radionuclide discharges to sanitary sewers, a situation that is potentially further complicated by the lack of state or federal guidance on the management of wastewater residuals containing radionuclides. As a result of the 1994 hearings, the Nuclear Regulatory Commission and the Environmental Protection Agency initiated a joint NRC/EPA survey of biosolids and ash. The survey, scheduled for completion by the end of 2001, will involve the collection and analysis of biosolids and ash samples from approximately 300 voluntary POTWs across the U.S.As a result of the NRC/EPA survey, and the historical events that preceded, municipal governments are facing increased pressure to address the potential presence of radionuclides in their wastewater treatment systems. To this end, the authors have combined their knowledge of municipal wastewater treatment operations, biosolids management and radiation protection to develop a phased approach that can be used to address the key issues associated with radionuclides in POTWs. The phases include reviews and inspections of potential dischargers, sampling and analysis reviews of existing biosolids management practices, and public relations communications. The approach can be tailored to specifically address concerns regarding the various health, safety, and environmental issues surrounding municipal residuals management programs. It should be noted that all phases are inter-related and can be performed separately or concurrently, depending upon the individual needs of the municipality. This approach also involves a vulnerability assessment that analyzes the entire residuals management program and pinpoints areas that may become problematic in the future.