A novel approach for toluene gas treatment using a downflow hanging sponge reactor

Abstract

A novel gas-scrubbing bioreactor based on a downflow hanging sponge (DHS) reactor was developed as a new volatile organic compound (VOC) treatment system. In this study, the effects of varying the space velocity and gas/liquid ratio were investigated to assess the effectiveness of using toluene gas as a model VOC. Under optimal conditions, the toluene removal rate was greater than 80%, and the maximum elimination capacity was observed at approximately 13 g-C m h. The DHS reactor demonstrated slight pressure loss (20 Pa) and a high concentration of suspended solids (up to 30,000 mg/L-sponge). Cloning analysis of the 16S rRNA and functional genes of toluene degradation pathways (tmoA, todC, tbmD, xylA, and bssA) revealed that the clones belonging to the toluene-degrading bacterium Pseudomonas putida constituted the predominant species detected at the bottom of the DHS reactor. The toluene-degrading bacteria Pseudoxanthomonas spadix and Pseudomonas sp. were also detected by tmoA- and todC-targeted cloning analyses, respectively. These results demonstrate the potential for the industrial application of this novel DHS reactor for toluene gas treatment.

Downflow Hanging Sponge System: A Self-Sustaining Option for Wastewater Treatment

“…The full scale and pilot scale DHS systems are being operating in Japan [10,16], Thailand [26], India [18,27,28], Egypt [20], and Vietnam [22,23] for various kinds of wastewater. Besides, DHS as a standalone bioreactor for rare metal recovery [29] phosphate recovery [30], gas scrubbing [31] and methane recovery [32] have also been investigated. Since, tremendous amount of researches are being carried out, more emphasis on its self-sustainability would help to validate its application for developing countries for domestic wastewater treatment.…”