Anaerobic biodegradability and toxicity of chlorophenols

Anaerobic biodegradation of several chlorophenol compounds under different conditions was studied. The experiments were carried out in batch and conti nuous processes and supplying or not an external carbon source. In the batc h bioassays the observed reductive dechlorination with external carbon was greater than without external carbon source. The addition of the external c arbon source stimulated the dechlorination, stabilized the process, and ens ured the presence of sufficient amount of active biomass. The continuous pr ocess was evaluated in a fluidized bed reactor fed with synthetic wastewate r containing 2,4,6-trichlorophenol (2,4,6-TCP) and acetic acid as primary s ubstrate. Removal efficiencies of 2,4,6-TCP were larger than 80% at influen t 2,4,6-TCP concentration of 25 mg/litre. No accumulation of lower chlorina ted phenols was observed in batch or continuous processes, suggesting compl ete dechlorination. (C) 1999 Published by Elsevier Science Ltd on behalf of the IAWQ. All rights reserved.