Abstract
The present study was conducted to determine the potential of utilizing the FeSO(4)·7H(2)O waste from the titanium manufacturing industry as an effective coagulant for treating industrial effluent. In this study, the secondary rubber processing effluent (SRPE) was treated using ferrous sulfate (FeSO(4)·7H(2)O) waste from the titanium oxide manufacturing industry. The FeSO(4)·7H(2)O waste coagulation efficiency was evaluated on the elimination of ammoniacal nitrogen (NH(3)-N) and chemical oxygen demand (COD) from SRPE. The central composite design (CCD) of experiments was employed to design the coagulation experiments with varying coagulation time, coagulant doses, and temperature. The coagulation experiments were optimized on the optimal elimination of NH(3)-N and COD using response surface methodology (RSM). Results showed that coagulant doses and temperature significantly influenced NH(3)-N and COD elimination from SRPE. The highest NH(3)-N and COD removal obtained were 98.19% and 93.86%, respectively, at the optimized coagulation experimental conditions of coagulation time 70 min, coagulant doses 900 mg/L, and temperature 62 °C. The residual NH(3)-N and COD in treated SPRE were found below the specified industrial effluent discharge limits set by DoE, Malaysia. Additionally, the sludge generated after coagulation of SRPE contains essential plant nutrients. The present study's finding showed that FeSO(4)·7H(2)O waste generated as an industrial byproduct in a titanium oxide manufacturing industry could be utilized as an eco-friendly coagulant in treating industrial effluent.