||Los Angeles-Orange County Metropolitan Area Project, Whittier, CA.;Environmental Protection Agency, San Francisco, CA. Region IX.;California State Water Resources Control Board, Sacramento.;Los Angeles County Sanitation District, CA.
The Carver-Greenfield process, which operates on the principle of multiple-effect evaporation, offers a considerable potential for drying wastewater solids. Drying of dewatered sludge cake by this method before incineration or pyrolysis offers a potential for energy self-sufficiency for the total sludge handling system. A continuous flow pilot-scale demonstration of the Carver-Greenfield process was conducted by the LA/OMA Project. A four month long demonstration study was conducted by the City of Los Angeles at their Hyperion Treatment Plant under a contract from the LA/OMA Project. The LA/OMA Project staff also visited an operating Carver-Greenfield installation treating waste activated sludge (Coors Brewery, Golden, Colorado) and another defunct installation which was plagued by operating problems (Omaha, Nebraska). From the pilot-scale demonstration study as well as from the field trips it was felt that the Carver-Greenfield process is a viable means for drying wastewater solids. The system did not seem to be too sophisticated for the use in a sewage treatment plant. Unless properly designed the system could loose considerable amount of process oil, emit hydrocarbons to the atmosphere, and create odor problem. On the basis of the experience gained from the present investigation, it was felt that a moderately large-scale demonstration plant is needed to collect reliable design and operating data.