Managing dissolved methane gas in anaerobic effluents using microbial resource management-based strategies

This study reports the findings of three independent microbial resource management-based strategies to manage dissolved methane (D-CH4) gas in anaerobic effluents. In the first approach, an aerobic methanotroph Methylococcus capsulatus was immobilized. A maximum of 1.75 kg COD m(-3) d(-1) at a hydraulic retention time of 0.5 h was recorded in the attached growth aerobic methane oxidizing reactor. In the second strategy, denitrifying methane oxidizing organisms (DAMO) were first enriched in a lab-scale batch reactor which enabled a maximum methane oxidation rate of 0.31 kg CODm(-3) d(-1). In the last strategy, a mixed community of aerobic ammonia oxidizers was immobilized on sponge carriers and used to convert the D-CH4 gas into useful biofuel methanol at a rate of 0.73 kg CODm(-3) d(-1) equivalent of COD with a methanol production of 31.5 g CODm(-3) d(-1). On a COD basis, the amount of methanol generated could denitrify nearly 7 mg L-1 of NO3-N.