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BIOLOGICAL TREATMENT OF HIGH STRENGTH PETROCHEMICAL WASTEWATER
Citation:
Humphrey, W. AND E. Witt. BIOLOGICAL TREATMENT OF HIGH STRENGTH PETROCHEMICAL WASTEWATER. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-79/172.
Description:
The biological treatment of a complex petrochemical wastewater containing high concentrations of organic chlorides, nitrates, and amines was initially studied using a sequence of anaerobic methanogenesis and oxygen activated sludge. Bench-scale and pilot-plant treatability studies were conducted using various composite samples and process wastewater blends. The results of preliminary studies indicated the need for stream segregation and waste reduction programs at the petrochemical plant. Segregation of components of the combined plant waste stream was required to eliminate nonbiodegradable materials and pretreatment minimized the concentration of substances which were toxic or inhibitory to biological treatment. Nitrates inhibited methanogenesis in the anaerobic system but quantitative removal of nitrates was accomplished. Only partial removal of chemical oxygen demand (COD) was achieved during anaerobic denitrification because of the relatively low nitrate/COD ratio. Anerobic methanogenic treatment also was unsuccessful in reducing the COD concentration to any great extent, even after pretreatment by anaerobic denitrification. The activated sludge system was effective in removing the biodegradable portion expressed as biochemical oxygen demand (BOD) of the pretreated combined wastewater stream; but the yellow color of the effluent was unacceptably dark. The activated sludge system performed equally well when high purity oxygen, or air was used for aeration.