Comparison of a novel electro-fenton method with Fenton's reagent in treating a highly contaminated wastewater

This study applied a novel electrochemical process called the Fered-Fenton method to treat a highly concentrated wastewater. By combining electrochemi cal reduction and chemical oxidation, the process can remove organic compou nds and heavy metals in a batch reactor. A PVC-stabilizer processing wastew ater was treated in this investigation owing to its high heavy metal concen tration (Pb = 7,500 mg/l) and high organic concentration (COD = 11,000 mg/l ). The major organic component was acetate. Direct anodic oxidation showed no effect on COD removal. Fenton's method only removed 36% of COD using 4,0 00 mg-Fe2+/l and 28,000 mg-H2O2/l dosage. In the Fered-Fenton process, abou t 89% of COD was removed with 2,000 mg-Fe3+/l and 28,000 mg-H2O2/l. Further more, the COD removal attained an efficiency of about 98% for 56,000 mg-H2O 2/l used. Results presented herein demonstrate that the Fered-Fenton method is superior to direct anodic oxidation and Fenton's method in this case. F urthermore, the changes of the intermediate compounds including acetate, ox adate, and formate during the reaction were analyzed, which provided us wit h the information to propose degradation reactions of the wastewater in thi s system.