Treatment of Paint Manufacturing Wastewater by the Combination of Chemical and Biological Processes

This work studied the combination of a chemical coagulation/flocculation step with an aerobic biological process, using feed-batch operation, to treat real paint manufacturing wastewater (PMW). The results indicate that the combination of coagulation flocculation and biological process is an efficient alternative in the treatment of PMW. For initials COD of 18590 mg/L, 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 BOD removals, and residuals COD and BOD of 1553 and 828 mg/L, respectively. However, the combination of chemical and biological process generates a clear effluent with residuals COD and BOD of 680 and 112 mg/L, corresponding to 96 and 92.5% removal rates, respectively. Aerobic biological treatment using feed batch operation permits a COD removal rate of rCOD = 873 mg/L, and an average growth yield coefficient of 0.3 g of biomass / g COD.