Dichloroethane Removal from Gas Streams by an Extractive Membrane Bioreactor

Abstract

A novel extractive membrane bioreactor (EMB) system, in which a silicone rubber membrane separates a contaminated gas stream from an aerated biomedium, extracted and biodegraded 1,2‐dichloroethane (DCE) from a gaseous waste stream. Selective transfer of the organic compound takes place through the silicone membrane to the biomedium, where biodegradation occurs. At a gas flow rate of 770 mL min−1 and an average DCE concentration of 0.65 mg L−1, the EMB, with 2.5 m2 of membrane surface contained in a spirally wound module, degraded 91% of the DCE. A biofilm grew on the membrane surface and caused a 600 mbar pressure drop at steady state conditions. The chloride ions released by DCE mineralization were 99% of the stoichiometric amount, while 60% of the total amount of carbon crossing the membrane as DCE was bioconverted to CO2. The overall mass transfer coefficient across the membrane in the absence of microbial activity was (0.8‐1.3) × 10−6 m s−1 and was controlled by the liquid film resistance. Extensive biofilm growth significantly lowered the DCE flux. Comparison of the EMB to a direct bioscrubbing process showed that the EMB system has superior volumetric efficiency.

Removal of dimethyl sulfide in a thermophilic membrane bioreactor

“…Several studies have reported the performance decline caused by biofilm growth. Dos Santos et al 23 attributed the decreasing reactor performance and increasing pressure drop over the liquid phase to extensive biofilm formation. Reij and Hartmans24 also observed a clogging of hollow‐fiber MBR with a biofilm of propene‐degrading Xanthobacter cells over of period of 3–6 months.…”

Membrane bioreactors for hospital wastewater treatment: recent advancements in membranes and processes

“…Compared with nonporous PDMS tubular membranes, the thickness of the non-porous PDMS layer on a substrate was decreased significantly, and resultant phenol mass transfer coefficients significantly increased to 4.1-6.5 m$s -1 [197,198]. These findings make EMBR suitable to treat inorganicorganic composite wastewater [199][200][201] Compared with conventional MBR with UF/MF membranes, MBR with NMBR (Fig. 8) can further improve solute rejection and enhance the quality of produced water.…”

Development of high-performance polydimethylsiloxane-based nanofibrous composite membranes for phenol removal from wastewater

“…to aliphatic compounds (e.g. dichloroethane [52,56], 1,3-dichloropropene [57] and dichloromethane [58,59]). Most of these compounds studied are hydrophobic or marginally soluble organic chemicals.…”

“…Most of these compounds studied are hydrophobic or marginally soluble organic chemicals. The EMBR application for treatment of wastewaters containing volatile organic compounds (VOCs) has been successfully extended to treating VOC-contaminated waste gases, and superior volumetric removal efficiency has been achieved compared to an alternative bioscrubbing process [56]. A variation of the EMBR used an anaerobic bioprocess to treat tetrachloroethene in a synthetic wastewater [60].…”