Dechlorination of 2,4,6-TCP by an anaerobic mixed culture

The dechlorination of 2,4,6-trichlorophenol (2,4,6-TCP) by 2,4- and 3,4-dichlorophenol (DCP)-adapted microbial communities was studied. We measured the dechlorination rate at 0.196 mg/L, and identified the intermediate products as 2,4-DCP, 4-monochlorophenol (4-MCP), phenol, methylphenol, and phenyl acetic acid. We also found that 2,4,6-TCP dechlorination was inhibited by treatment with sulfate, nitrate, and ferric hydroxide, but enhanced by treatment with manganese oxide. However, we found that the addition of acetate had no significant effect on dechlorination, and also observed that 2,4,6-TCP dechlorination was reduced to 20 % following the addition of glucose. Following the individual addition of six heavy metals at concentrations of 1 mg/L each, 2,4,6-TCP was completely dechlorinated within 8 days. However, at concentrations of 10 100 mg/L, lead, nickel and mercury inhibited dechlorination and zinc, copper, and cadmium delayed dechlorination. Treatment with the microbial inhibitors bromoethanesulfonic acid (BESA) and vancomycin led to the observation that eubacteria constitutes the major microbial population involved in dechlorination.