Treatment of tannery wastewater with high nitrogen content using anoxic/oxic membrane bio-reactor (MBR).

Bench scale membrane bio-reactors were operated to investigate the treatment efficiency of tannery wastewater with high organic and nitrogen contents and the optimum operating conditions were derived. The optimum ratio of the volume of anoxic denitrification tank to aerobic nitrification tank was 50% when denitification/nitrication MBR process was used to treat tannery wastewater. It was also found that supplementation of phosphorus to maintain COD:T-P ratio of 100:1 was needed to achieve the best performance. Under these conditions, the effluent COD and T-N were 160 and 54 mg/L, respectively which satisfied the effluent limits for the tannery wastewater.