The thermal conditioning research program was conducted as part of an overall long-term sludge management study for the Los Angeles and Orange County metropolitan areas. The major goal of this portion of the study was to investigate the advantages of thermal conditioning of primary and waste activated sludges prior to anaerobic digestion, on a continuous flow and pilot scale basis. The studies were designed to demonstrate whether thermal conditioning would help produce increased gas production and volatile solids destruction during subsequent anaerobic stabilization of the sludge. Anaerobic digestion and anaerobic filtration were used for sludge stabilization. The effects of thermal conditioning on sludge dewaterability were studied by means of dewatering via a filter press, vacuum filter, scroll and basket centrifuges and belt filter press. Other studies of interest included the fate of pathogens and heavy metals, and the production and control of odors during the thermal conditioning process. The pilot scale thermal conditioning unit was tested using a variety of operational conditions. Operating temperatures and pressures were varied and thermal conditioning with and without the use of oxygen was investigated. Two types of wastewater sludges were used: waste activated sludge and a blend of 65 percent raw primary and 35 percent waste activated sludge. An energy analysis was conducted to determine the net energy demands of including thermal conditioning in the sludge process.

Caption title. "May 1984." "EPA-600/2-84-104." Microform.