performance evaluation of chemical coagulation and electro-fenton combined processes treating real pharmaceutical wastewater

Background: 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. methods: 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. further, 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. results: 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. conclusion: it is generally concluded that combined processes are more effective than the coagulation process alone in removing organic compounds from pharmaceutical wastewater.