기체상 톨루엔 처리를 위한 중공사막 결합형 생물반응기의 적용성 검토

Abstract

A hollow fiber membrane bioreactor(HFMB) has emerged as a treatment technology for the air emission of biodegradable volatile organic compounds(VOCs). The Hollow fiber membrane serves as a support for VOC-degrading microorganisms and provides a large surface area for the VOC and oxygen mass transfer. In this study, a lab-scale HFMB was operated to investigate the feasibility of applying this novel technology for the removal of toluene, the model VOC. At a liquid medium exchange rate of 0.6L/day, the HFMB showed stable long-term performance with high toluene-degrading activities in a range of 2.69～3.18㎍ toluene/mg SS․hr. In addition, the maximum elimination capacity(EC) was found to be 500g/m3․hr that was significantly higher than that reported in the literature. These findings imply that the HFMB be a feasible alternate over conventional packed-bed type biofilters. However, bioreactor performance gradually declined when the HFMB was subjected to a low liquid medium exchange rate, presumably due to the limitation of nutrients necessary for microbial growth and/or the accumulation of toxic byproducts. Also, an increase in pressure drop across the hollow fiber membrane module was observed with the increasing operation time, indicating that biofouling on the membrane surface by microorganisms played a major role on the pressure drop. As a result, more integrated research is required to improve the HFMB performance as well as to minimize the pressure drop across the membrane.