A report on the combination of chemical and biological processes in the treatment of paint manufacturing wastewaters

Abstract

The project aimed at the study of the combination of a chemical coagulation/flocculation step with an aerobic biological process, using feed batch operation, to treat real paint manufacturing wastewater. The results of the study indicate that the combination of coagulation/ flocculation and biological processes is a cost effective in the treatment of paint manufacture wastewaters. For initials, Chemical Oxygen Demand (COD) of 18590 mg/L, Biological Oxygen Demand (BOD) of 1492 mg/L and colour of 0.9 absorbency, coagulation/flocculation using iron chloride and chimec 5161 allows 92% of COD, 97% of colour and 44.5% of Biological Oxygen Demand (BOD) removals, and residuals Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD) of 1553 and 828 mg/L respectively. However, the combination of chemical and biological process operates a clear effluent with residuals Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD) of 680 and 113 mg/L, corresponding to 96 and 92% removal rates respectively. Aerobic biological treatment using feed batch operation permit a removal rate of r= 873 mg/L, and an average growth yield coefficient of 0.3 g of biomass/g COD.