Cometabolic degradation of trichloroethylene in a hollow fiber membrane reactor with toluene as a substrate

Abstract

Contamination of air by volatile organic components (VOCs) is a serious health concern in the present industrial age. To address this issue, a study was devoted to the development of a hollow fiber membrane bioreactor (HMBR), where microorganisms immobilized on the outside of a polyvinylidene fluoride (PVDF) membrane contribute to removing toluene and trichloroethylene (TCE) from air passing through the filter. Waste gas containing toluene and TCE as contaminants was passed through the membrane and shifted to a liquid phase. The performance of fibrous-bed biofilm was evaluated with toluene as carbon source. After over 9 months of continuous operation, long-term performance was demonstrated. The hollow fiber membrane provided a large gas–liquid interface which enabled the efficient removal of the pollutants. Under inlet concentrations of 450–2400 mg m −3 for toluene and 100–160 mg m −3 for TCE, the maximum elimination capacity of toluene and TCE were 0.275 g m −2 h −1 and 0.0016 g m −2 h −1, corresponding to a volumetric of toluene membrane removal rate of 1479 g m −3 h −1 and 8.5 g m −3 h −1, respectively. During the experiments, 95% of toluene as well as 22.1% of TCE removal efficient were observed. No intermediate products such as dichloroethylenes (DCE) and vinyl chloride (VC) were detected during cometablism. Overall, the feasibility of sustained higher anaerobic biotreatment of toluene and TCE in a HFMR was approved.