Improvement of bacterial methane elimination using porous ceramsite as biocarrier

BACKGROUNDMethane is a greenhouse gas (GHG) which contributes to climate change. Biofiltration with immobilized methane-oxidizing bacteria (MOB) is a promising option to eliminate methane. In order to achieve high methane removal efficiency (RE), the appropriate carrier material with favorable characteristics to perform well in MOB immobilization and methane elimination, must be selected. RESULTSA MOB consortium was enriched from landfill soil and immobilized on porous materials to eliminate methane at high (approximate to 20% (v/v)) and low (approximate to 1% (v/v)) concentrations. The methane elimination capacities of immobilized MOB were evaluated and the microbial immobilization abilities of materials were compared. Results showed that MOB inoculated in black ceramsite (BC) permitted the highest elimination capacity (EC) of 5.36 0.29 mu mol h(-1) cm(-3) at the methane concentration of approximate to 20% (v/v), which was almost 3.6 times that of suspended cells. At a methane concentration of approximate to 1% (v/v), the MOB incorporated with red ceramsite (RC) exhibited the optimal EC of 1.48 +/- 0.03 mu mol h(-1) cm(-3), which was 64% higher than the control. Biophosphorus tests showed that BC and RC could immobilize more MOB cells than active carbon (AC), and SEM images, MB adsorption tests, BET and FTIR indicated that their large pore and surface properties might favor MOB immobilization. CONCLUSIONCeramsite with desirable porosity and surface properties could promote MOB immobilization, and further improve the methane elimination capacity, and might be a favorable biocarrier in MOB biofilters. (c) 2018 Society of Chemical Industry