REDUCTIVE DECHLORINATION OF TETRACHLOROETHENE TO ETHENE BY COMPOST SAMPLES WITH DIFFERENT MATURITY

摘要

In this study, microcosms were set up to evaluate two compost samples, bagasse compost and yardwaste compost, for their capacity of reductive dechlorination of tetrachloroethene (PCE). The experiments were conducted by adding 5 g samples into serum bottles containing 300 mM PCE, and then the bottles were sealed with Teflon seal. The PCE and its by-products concentrations were monitored. The experimental results showed that all the composted samples had the capacity to reduce PCE, and the less matured sample had greater reductive power than the more matured one. However, the addition of 2-bromoethanesulfonic acid (one inhibition agent for methanogens) would decrease the dehalogenation rate of PCE for bagasse compost samples significantly, while sodium molybdate 2-hydrate (one inhibition agent for sulfur reducing bacteria) would alter the reducing capacity of yard waste compost samples, indicating that the microorganisms responsible for the dehalogenation of PCE were different in different compost samples. The solution remained at suitable pH for dechlorination throughout the experiment, suggesting compost samples had enough buffering capacity. Overall, due to their high carbon content, diverse microbial activity, and protective physical structure, compost samples could serve as suitable media for the purpose of reductive dechlorination of PCE.