Investigation into the fate of a metabolic uncoupler, 2,6-dichlorophenol in the sequence batch reactor system

The fate of a metabolic uncoupler, 2,6-dichlorophenol (2,6-DCP) was investigated in the sequence batch reactor systems for 3 months by determination of 2,6-DCP in the dissolved and particulate phases. Two sequence batch reactors were used: one system was used as a control, while the other received 2,6-DCP concentrations equal to 20 mgL^-1. The results revealed that 70 ± 5% of 2,6-DCP was still in the final effluent during the day of 1-40. During the next days (days 40-70), 10 ± 4% was biodegraded with the adsorption fraction increasing from 25 ± 5% of day 40 to 50 ± 2% of day 70, while the effluent part decreasing from 65 ± 4% to 40 ± 3%. Up to the end of the experiment (days 70-90), 20 ± 2% of 2,6-DCP was biodegraded, 35 ± 2% was removed via the effluent, while 45 ± 3% was removed by the activated sludge. The addition of 2,6-DCP initially deteriorated the removal of biological nutrient (days 1-40). After acclimatization of biomass, the biological nutrient removal was recovered and 2,6-DCP could reduce sludge generation by about 5% (days 70-90).