Treatment of bleaching effluent in sequential activated sludge and nitrification systems.

Biological dehalogenation of bleaching effluents was studied in sequential activated sludge and nitrification systems. Increases in inorganic chloride (ICl) indicated that dechlorination of bleaching effluent takes place in both systems. In activated sludge system released ICl was 4.5-7 mg/l at TOC loading rate 0.03 - 0.07 mg/mg VSS.d, respectively. But it was decreased from 10 mg/l to 3 mg/l at TOC loading rate 0.006 - 0.06 mg/mg VSS.d, respectively.