Anaerobic biodegradation of ethylene dichloride in an anaerobic sequential batch reactor

Aims: The efficiency of an anaerobic sequencing batch reactor (ASBR) in ethylene dichloride ( EDC) and chemical oxygen demand (COD) removal at different operational conditions was evaluated. Materials and Methods: Biological EDC and COD removal was studied in a laboratory scale ASBR. The ASBR was seeded at the start-up with granular anaerobic sludge of sugarcane industry and operated at different organic loading rates (OLR), EDC loading rates, and influent concentration of COD and EDC. Results: During start-up period, COD removal efficiencies of above 80% were selected for reactor adaptation to achieve steady state during 48 days of operation. Maximum COD removal efficiency was 95% with an influent COD concentration of 1700 mg/L at 0.5 gCOD/L.d, and the efficiency rapidly dropped with increasing influent COD concentrations and OLR. When the EDC loading rate was adjusted between 0.6 to 4.7 gCOD/L.d, the EDC removal efficiencies were 95% and 46%, respectively, with influent EDC concentrations of 2000 and 16000 mg/L at the end of EDC loading stage. The kinetic study showed that the EDC and COD removal by ASBR followed the second order kinetic. Conclusions: Based on the results of this study, the ASBR process is successfully applicable for biodegradation of the COD and EDC (>90%) in wastewater treatment. The kinetic study showed that, at same time, ASBR capable to removing COD rather than EDC.