Treatment of commercial industrial wastewater using electrocoagulation: Understanding effect of operating conditions

Abstract The wastewater generated from various stages in pharmaceutical industries such as production, washing processes, and formulation contains a wide range of hazardous chemicals. The objective of this study is to investigate the application of electrocoagulation (EC) for the treatment of real industrial pharmaceutical wastewater obtained from various processing stages. Aluminium and stainless steel (SS) electrodes were used to conduct the treatment. The effects of important operating conditions for EC such as current density (1.08–3.33A/cm 2 ), electrode spacing (varied from 4 to 7 cm), pH (from 4.0 to 10.0), and poly aluminium chloride (PAC) dose (chemical oxygen demand [COD]: PAC ratio as 1:0.025–1:0.3) on the COD removal efficiency have been studied. TDS and electrical conductivity were also monitored during the treatment. The optimum COD reduction was observed at a current density of 1.33 A/cm 2 , an electrode spacing of 5 cm, a pH of 7, and a COD: PAC dosage ratio of 1:0.2. The maximum COD reduction recorded for samples A, B, C, and D corresponding to various stages were 62%, 71%, 51%, and 86%, respectively. It was also concluded that the COD reduction was improved after the addition of external coagulant as PAC. The research work has clearly confirmed that the EC process can be considered as an effective method of treatment for COD reduction.