| description |
For evaluating tobermolite as a bed material for methanotrophic biofiltration, a lab-scale biofilter was operated over 5 months, with perlite as a reference material. Removal efficiency reached 61% in the perlite-biofilter, while 100% in the tobermolite-biofilter with a retention time (RT) of 20 min at inlet methane concentrations of 40,000-100,000 ppm. As the RT of the tobermolite-biofilter was stepwise reduced, the efficiency reached 100% at 15 min, and 80% at 10 min with acclimation periods. Maximum elimination capacity of the tobermolite-biofilter was 8,592 g-CH4•m-3•d-1 (10 min), over 5 fold greater than that of the perlite-biofilter. Pyrosequencing results showed that methanotrophs comprised 6 vs. 77% in the perlite- vs. tombermolite-biofilter, respectively. In addition, quantitative PCR showed that methanotrophic population levels were stable in the tobermolite-biofilter during the operation. The results indicated that selective growth and population stability of methanotrophs by tobermolite resulted in the high efficiency in methane-biofiltration. |