Biological removal of chloro-organic compounds from bagasse soda pulp bleaching effluent by Coriolus versicolor

Abstract

The potential of rainbow fungus (Coriolus versicolor) for bioremediation of bagasse soda pulp bleaching effluent containing chlorinated organic compounds was investigated without co-substrate addition. Initially, the effect of each of the operating variable including time, temperature, pH, and biomass on color reduction was investigated. The highest color reduction (percentage of the original value) was observed applying a treatment time of 6 days (58%), a pH of 3 (48%), a biomass dose of 9 g L -1 (59%), and a temperature of 35°C (48%). Then, the combined effect of parameters was studied to reach the best combinations of parameters leading to the highest color reduction. The highest performance of rainbow fungus on color reduction (66%) was observed when applying the combination of variables including temperature, treatment time, biomass dose, and pH combination of 35°C, 6 days, 9 g L -1, and 3, respectively. At this condition, COD and BOD of effluent were decreased by 45% and 53%, respectively. It was also found that Coriolus versicolor can efficiently reduced various toxic compounds; chlorophenols, chloroguaiacols, and chlorocatechols present in the effluent to the levels less than their lethal concentration ( 96 LC 50 ) even without addition of cosubstrate. In general, rainbow fungus can efficiently modify the undesirable physico-chemical characteristics of bagasse soda pulp bleaching effluent.