Performance Evaluation of Chemical Coagulation and Electro-Fenton Combined Processes Treating Real Pharmaceutical Wastewater

Pharmaceutical wastewater mainly contains high levels of organic matter. In order to produce a suitable wastewater for discharge into the municipal sewage, chemical and electrochemical methods have been studied. The aim of this study was to evaluate the efficiency of chemical coagulation/electro-Fenton combination process in chemical oxygen demand (COD) reduction of pharmaceutical wastewater.

The effect of Poly aluminum chloride (PAC) concentration 25-300 mg/L and pH of 3-7-10 were investigated. The effluent of chemical coagulation stage was transferred to the electro-Fenton stage. Fur
thur, the effect of H2O2 concentration 100 - 4000 mg/L, contact time of 15-120 min, voltage of 10-30 v and pH of 3-10 were investigated.

The results showed that the highest removal rate of COD was 93.5% in the optimal conditions at coagulant dose 200 mg/L and pH of 7 for the coagulation process, and at concentration of 100 mg/L hydrogen peroxide, the voltage of 20, pH of 3 and contact time of 30 min for the electro-Fenton process (EFP). The results showed that chemical and electrochemical processes are effective methods for the  pharmaceutical wastewater treatment.

It is generally concluded that combined processes are more effective than the coagulation process alone in removing organic compounds from pharmaceutical wastewater.