Dimethyl Sulfide Removal from Synthetic Waste Gas Using a Flat Poly(dimethylsiloxane)-Coated Composite Membrane Bioreactor

Abstract

The reduction of volatile organic sulfur emissions should be completely as they cause odor nuisance, even when they are emitted in very small amounts. In general, biofilters are applied for odor reduction, but their operational control is limited. A new biotechnique for the treatment of complex emissions is the use of membranes integrated within bioreactors (MBRs). In this study, the reactor performance of MBRs for removal of dimethyl sulfide (DMS) as a model compound is presented. Composite membranes with a poly(dimethylsiloxane) (PDMS)-coating layer were used. The MBRs were inoculated with the sulfur-degrading culture Hyphomicrobium VS or a suspension of Hyphomicrobium VS, ammonium-oxidizing bacteria (AOB), and nitrite-oxidizing bacteria (NOB) to colonize the PDMS-coating layer. Although inoculation with AOB and NOB might give rise to competition for space on the membrane, their presence in the MBRs appeared to be positive as they co-oxidize DMS. Dimethyl sulfide elimination depended on the inoculum type, DMS inlet concentration, gas residence time, and membrane polymer. For equal loading rates, the elimination capacity (EC) increased at larger gas residence times and inlet concentrations. The maximum EC obtained with the MBRs was 4.8 kg of DMS x m(-3) x d(-1). This value is higher than any reported figure for biofilters and biotrickling filters.

Enhanced removal of dimethyl sulfide from a synthetic waste gas stream using a bioreactor inoculated with Microbacterium sp. NTUT26 and Pseudomonas putida

“…NTUT26 and Pseudomonas putida, respectively. The value of 96.1 g-S/m 3 /h is much higher than those reported for other biosystems (7.1, 36.6, 10.8, 51.8, and 29.9 g-S/m 3 /h) [4,26,27,29,30]. Thus, the bioreactor inoculated with Microbacterium sp.…”

“…Such chemical and/or physical methods are often effective in their primary objective-the removal of the target compound-but they are associated with both high energy demands and high costs and easily result in secondary pollutants. In comparison, biological waste gas treatments, such as those consisting of a biofilter, are ecologically and economically more favorable, especially for the removal of odorous gases at low concentrations [4]. Dimethyl sulfide is the least biodegradable compound among the odorous sulfur-containing gases [5,27]; consequently, improved systems need to be designed that enhance DMS degradation.…”

Removal of dimethyl sulfide in a thermophilic membrane bioreactor

“…A maximum EC V of 54 g m −3 h −1 (EC SA 0.108 g m −2 h −1 ) was observed in the MBR at a mass loading rate of 64 g m −3 h −1 (RE 84%). Previously, De Bo et al 15 studied DMS removal in an MBR inoculated with Hyphomicrobium VS at 30 °C using a 2.5 µm PDMS/PVDF membrane. The authors obtained a maximum EC V of 133 g m −3 h −1 (EC SA 0.266 g m −2 h −1 ) at a gas residence time of 24 s with a removal efficiency of 89%.…”

“…Recently membrane bioreactors (MBRs) have been developed for removal of hydrophobic volatile organic compounds (VOCs) from waste gases 15, 16. The main advantage of MBRs over traditional bioreactors is the enhanced mass transfer of hydrophobic pollutants.…”

“…The aim of this study was to investigate the possibility of removal of DMS from waste gases under thermophilic conditions (52 °C) in an MBR using a polydimethylsiloxane/polyvinylidene difluoride (PDMS/PVDF) composite membrane and to examine the long‐term stability of the reactor at elevated temperature. The commercially available PDMS/PVDF membrane was selected because a previous study by De Bo et al 15 has proven its suitability for membrane integrated bioreactors.…”