| description |
Methane and non-methane volatile organic compounds (NMVOCs) are simultaneously produced from landfill. Four lab-scale biofilters (BF) packed with pumice and granular activated carbon (10:1, w/w) were operated with 10,000-60,000 ppm CH4 and 10-200 ppm NMVOCs such as dimethyl sulfide (DMS), benzene (B) and toluene (T) at a space velocity of 3 h-1. Ribosomal tag pyrosequencing and quantitative PCR were performed for bacterial community analysis. Methane elimination capacities proportionally increased with methane loads in all BFs. Methane could be removed up to 82.8%, while DMS, B and T were completely removed. Compared to BF 1 without the NMVOCs, DMS alone significantly enhanced the methane removal performance (BF 2), whereas B/T alone had no effect on it (BF 3). However, DMS and B/T together significantly reduced the performance (BF 4). A canonical correspondence analysis result showed that DMS and B/T strongly influenced relative abundances of the microbial composition. DMS significantly diversified and modified the bacterial and methanotrophic communities, but its effect was nullified by coexistence of B/T as same with the performance result. The existence of DMS and B/F favored the growth of Methylosarcina and Methylomonas, respectively, resulting in the substantial change of methanotrophic community. However, methanotrophic population densities on a packing material basis did not significantly differ among the BFs 1-4. It was apparent that the variation of methanotrophic performances resulted from the community change by the NMVOCs. Our results proved that the co-emitted NMVOCs along with methane are an important abiotic factor to influence performance and microbial community of methanotrophic biofilter, and also suggest that interaction effects among NMVOCs are unpredictable. |