Moving from alcohol to methane biofilters: an experimental study on biofilter performance and carbon distribution

BACKGROUND Biofilters can be used to eliminate different gaseous pollutants including alcohols (e.g. methanol, ethanol) and methane (CH 4 ) individually or in a mixture. In this regard, the biofilter adaptability to feed composition variation is an industrial requisite. Inlet gas composition changes also give a better insight about carbon input and end‐points in biofilters. In this study, the gradual conversions of two biofilters from methanol and ethanol to CH 4 were investigated. RESULTS Both biofilters reached 100% removal efficiencies for the alcohols with no initial inoculation. Keeping the total inlet load constant (30 ± 1.3 g m −3 h −1 ), CH 4 was progressively substituted in the feed with corresponding alcohol:CH 4 mass ratios of 3:1, 1:1, 1:3 and 0 g alcohol :g CH4 . Maximum CH 4 removal efficiencies of 52% and 29% were obtained (respectively) for biofilters started with methanol and ethanol. By moving from alcohols to CH 4 biofilters, the gas phase output carbon increased from 273 to 666 g carbon day −1 and from 377 to 681 g carbon day −1 respectively for the methanol‐ and ethanol‐based biofilters. CONCLUSION This study showed a successful treatment based on inlet pollutant alteration from methanol or ethanol to CH 4 in two separate biofilters. However, the methanol‐based biofilter displayed a better performance and a shorter acclimation time for CH 4 conversion. © 2019 Society of Chemical Industry