Treatment of automotive wastewater by coagulation-flocculation using poly-aluminum chloride (PAC), ferric chloride (FeCl3) and aluminum sulfate (alum)
A physicochemical treatment (coagulation-flocculation) was applied for automotive wastewater using poly-aluminum chloride (PAC), ferric chloride (FeCl3) and aluminum sulfate (alum) aided by anionic polyacrylamide as flocculant to determine the effectiveness of coagulation method for removal of COD, TSS and heavy metals (Fe, Ni and Zn). The results obtained proved that PAC was comparatively more efficient to FeCl3 and alum. At defined optimum experiment condition (coagulant dose: 70 mg/L, coagulant aid dose: 2 mg/L and pH 7), PAC showed 70% removal for (chemical oxygen demand) COD and 98% of (total suspended solid) TSS. For FeCl3 and alum, the maximum removal for COD were 64% and 54%, meanwhile TSS removal were 91% and 94%. Heavy metals removal using PAC also showed better results in which produced 98% of iron removal, 83% of zinc removal and 63% of nickel removal under optimum condition. The comparison revealed that the use of PAC aided by anionic polyacrylamide produced higher removal for COD, TSS and heavy metals compared to FeCl3 and alum for automotive wastewater treatment.