Landfarming of municipal sewage sludge at Oak Ridge, Tennessee

The City of Oak Ridge, Tennessee, has been applying municipal sanitary sludge to 9 sites comprising 90 ha on the US Department of Energy (DOE) Oak Ridge Reservation (ORR) since 1983. Approximately 13,000,000 L are applied annually by spraying sludge (2 to 3% solids) under pressure from a tanker. Under an ongoing monitoring program, both the sludge and the soil in the application areas are analyzed for organic, inorganic, and radioactive parameters on a regular basis. Organic pollutants are analyzed in sludge on a semiannual basis and in the soil application areas on an annual basis. Inorganic parameters are analyzed daily (e.g., pH, total solids) or monthly (e.g., nitrogen, manganese) in sludge and annually in soil in application areas. Radionuclides (Co-60, Cs-137, I-131, Be-7, K-40, Ra-228, U-235, U-238) are scanned daily during application by the sewage treatment plant and analyzed weekly in composite sludge samples and annually in soil. Additionally, data on radioactive body burden for maximally exposed workers who apply the sludge show no detectable exposures. This monitoring program is comprehensive and is one of the few in the United States that analyzes radionuclides. Results from the monitoring program show heavy metals and radionuclides are not accumulating to levels in the soil application areas