Treatment of bleaching effluent in sequential activated sludge and nitrification systems

Dechlorination and degradation mechanisms of bleaching effluent were studie d in a sequential activated sludge and nitrification reactor. Effect of ble aching effluent on dechlorination performances was examined at various orga nic loading rates in the system. Released inorganic chlorine (ICI) was incr eased from 4.5 to 8.5 mg/l in the first stage activated sludge reactor whil e it was decreased from 10 to 2.5 mg/l in the subsequent nitrification reac tor. Removal efficiencies of AOX were found as 15-33% and 5-25% in the acti vated sludge and the nitrification reactor respectively. TOC removal effici encies achieved were 67-85% in the activated sludge reactor. The removal ef ficiency of NH4 achieved 94-98% in the nitrification reactor. (C) 1999 Publ ished by Elsevier Science Ltd on behalf of the IAWQ. All rights reserved.