Aerobic cometabolic biodegradation of 1,1,2,2-tetrachloroethane: a microcosms study

The objective of this work was to study a process of 1,1,2,2-tetrachloroethane (TeCA) biodegradation via aerobic cometabolism by methane-utilizing and propane-utilizing microbial cultures. Both cultures were studied by means of slurry microcosm tests; the propane-utilizing culture was further studied in liquid/gas bioreactors. TeCA was biodegraded by both microbial cultures via aerobic cometabolism in the 0-600 μg/L concentration range. The process was successfully continued for several months without any apparent inhibitory or toxic effect on the microbial cultures tested. In bioaugmented microcosms, the inoculation of the propane-utilizing culture developed in the slurry microcosms led to a marked reduction of the lag-period required for the onset of TeCA degradation. The positive results obtained from the liquid/gas reactors show that it is possible to grow the isolated propane-utilizing culture in a liquid/gas bioreactor without any observable loss of TeCA degradation capacity. This conclusion is relevant with respect to the production of significant amounts of inoculum to utilize in bioaugmentation treatments.