Improvement of methane biofiltration by the addition of non-ionic surfactants to biofilters packed with inert materials

摘要

The effect of non-ionic surfactants on the biofiltration of methane (CH_4) was analyzed. Two biofilters (BF) treating CH_4 were operated for one year at fixed CH_4 concentration of 4.8 gm~(-3) and air flow rate of 0.25 rrr~(-3)h~(-1). Three polyoxyethylenes (Brijs), and 3 mono polyoxyethylenesorbitans (Tweens) were added to the nutrient solution at a concentration of 0.5% (w/w). Without surfactant, CH_4 conversion had an average level of 35%, with Brijs the CH4 conversion varied between 38% and 46%, and with Tweens between 43% and 48%. The non-ionic surfactants decreased the biomass accumulation in the packed bed due to their detergent character. Biofilters were operated in a range of nitrogen concentration in the nutrient solution from 0.5 to 2gN L~(-1) using Tween 20 at a concentration of 0.5% (w/w). The EC_(max) observed in this study, 45 gm~(-3 )h~(-1), occurred when the nitrogen concentration was 1 gN L~(-1) .