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

The effect of non-ionic surfactants on the biofiltration of methane (CH4) was analyzed. Two biofilters (BF) treating CH4 were operated for one year at fixed CH4 concentration of 4.8 g m−3 and air flow rate of 0.25 m−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, CH4 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 2 gN L−1 using Tween 20 at a concentration of 0.5% (w/w). The ECmax observed in this study, 45 g m−3 h−1, occurred when the nitrogen concentration was 1 gN L−1.

► The control of biomass accumulation (exo-polymers) in the packed bed using non-ionic surfactants improves the stability and performance of biofilter.
► The CH4 conversion in the biofilter increases around 40% when surfactant is added.
► Non-ionic surfactants are economic and biodegradable compounds which can be used in the biofiltration of low water soluble pollutants.
► The effects of non-ionic surfactants allow decreasing the biofilter size and operating costs for treating low water soluble compounds, such as CH4.