Physicochemical and Biological Treatability Studies on Surfactant Wastewaters

Laboratory-scale physicochemical and biological treatability studies were performed on wastewaters discharged from an industry producing household and heavy-duty detergents of powder and liquid type. The characterization of effluents led to the conclusion that the industry was highly pollutant in terms of BOD₅, COD, surfactant, phosphorus, oil-grease, suspended solids and pH. By the use of lime in the precipitation stage about 80 % of COD and more than 90 % of phosphorus and anionic surface active agents could be removed. Following the treatment with lime the biodegradation of these wastewaters was investigated in continuously fed activated sludge units. The biokinetic constants of the reaction were determined as k = 0.76 d⁻¹, K_s = 972 mg/l COD, a = 0.58 mg O₂/mg COD, b = 0.044 mg O₂/mg MLVSS.d. The experimental findings were used in the design of a full-scale treatment system.