Compartmentation of microbial communities in structure and function for methane oxidation coupled to nitrification–denitrification

Abstract

A hollow-fiber membrane biofilm reactor was designed and constructed to achieve simultaneous nitrification–denitrification coupled to methane oxidation in low O2/CH4 ratio and high nitrogen removal rate. Three O2/CH4 ratio stages were operated. Ammonia removal rates reached 77.5 and 95 mg/(L·d) at the O2/CH4 ratio of 1.47 and 2.1, respectively. Microbial community analysis revealed that aeration through physical partition and O2/CH4 ratio stages achieved compartmentation of microbial community in structure and function. Combined functional genes analysis using qPCR, the aeration through gas distributer was proved to promote the enrichment of autotrophic ammonia oxidizers in the suspended liquid/mixed filler samples, and the aeration through hollow-fiber membrane favored the growth of methanotrophs and heterotrophic nitrification-aerobic denitrification bacteria. This study helps to develop effective regulatory strategies for high nitrogen removal based on the understanding of the community assembly process and the key driving factors.