Optimization of coagulation process for the treatment of the characterized slaughterhouse wastewater

The wastewater of a slaughterhouse was characterized for parameters like pH, COD, BOD, TDS and TSS. All parameters were above the permissible limits of National Environmental Quality Standards of Pakistan. The slaughterhouse wastewater is rich in organic matter with BOD and COD being 5820 mg/L and 6970 mg/L, respectively. In this study, wastewater was treated by coagulation process using lime and alum (both individually and in combination) as coagulants. COD removal increased with increase in alum dose to a maximum of 92%. The high sludge volume made the process infeasible. Increase in lime dose increased the COD reduction to a maximum of 74%. The sludge settling speed was very high and sludge volume was low as compared with alum. The combined doses of lime and alum gave removal of COD to a maximum of 85% with sludge volume comparable to lime. The optimum dose of lime and alum reduced BOD, TSS, and TDS to a maximum of 85%, 98% and 77%, respectively. The combination of coagulation/precipitation gave enhanced COD removal with minimal sludge produced.