ABSTRACT
Tar is decanted from the condensate and the remaining aqueous waste, known as the flushing liquor or weak ammonia liquor, is the major source of coking plant wastewater. The goal of biological treatment of coking process wastewater is to mineralize organic contaminants and to oxidize the ammonia and thiocyanate to nitrate. One of the most commonly employed biological treatment processes for coking plant wastwaters is activated sludge. Biological conversion of other organic and inorganic compounds present in coking plant wastewater has been well documented. The pilot-scale aeration basins were seeded with acclimated biomass obtained from the plant’s current treatment system. The reduction in biochemcial oxygen demand and dissolved organic carbon are indicators of organic removal by aerobic heterotrophic microorganisms. The high degree of bioconversion observed for phenolics and heterocyclic nitrogenous compounds makes the two-stage activated sludge process an attractive alternative for treating coking plant wastes.
