Microbial monooxygenase-catalyzed biodegradation of gas-phase chlorinated hydrocarbon in a parallel trickling biofilter system

A novel parallel trickling biofilter (TBF) system consisting of two units of TBF in a parallel mode, one for trichloroethylene (TCE) biodegradation and the other for biofilm reactivation, was developed and operated to evaluate the potential of this system for the long-term continuous treatment of gas phase TCE using B. capacia G4 biofilm. TCE removal efficiency and degradation rate decreased with increase in inlet TCE concentration due to the toxic effect of TCE and its degradation products. More than 50% of TCE was degraded for feed concentrations ranging from 5 to 17 ppm, and almost 100% removal was achieved when TCE was introduced at concentration of < 5 ppm_v. The TCE degradation decreased drastically after the introduction of high concentration of TCE above 28 ppm_v, which showed that the parallel TBF system consisting of B. cepacia G4 biofilm could be applied for the treatment of low TCE concentration below 20 ppm_v. TCE removal efficiency was decreased with decrease in empty bed retention time (EBRT). The low removal efficiency of 26% was obtained at 2.6 min of EBRT. When the parallel TBF system was operated for the long-term removal of TCE, semi-continuous supply of growth substrate led to the increase of large quantities of biomass, which clogged the system. Thus, the method for the biomass reactivation under non- or limited-growth condition needs to be investigated. This is an abstract of a paper presented at the 223rd ACS National Meeting (Orlando, FL 4/7-11/2002).