Conductive materials enhance anaerobic membrane bioreactor (AnMBR) treating waste leachate at high organic loading rates

Abstract

The treatment of landfill leachate using anaerobic membrane bioreactors (AnMBRs) often faces challenges such as poor removal efficiency, low methane yield and membrane fouling. This study applied AnMBRs with incrementally adding conductive materials to enhance the treatment of landfill leachate under high organic loading rates(35 kg COD/(m³∙d)). With 50 g/L activated carbon, COD removal percentages and methane yield increased to 81.03 ± 2.12% and 0.34 ± 0.01 m³ CH₄/kg COD, respectively. The addition of conductive materials dramatically increased EPS content of the sludge, which not only enhanced inter-microbial electron transmission but also increased the sludge's biological activity. The primary membrane fouling type for AnMBRs was cake layer, with Ca being the main inorganic foulant, and humic substances and proteins being the principal organic foulants. Combined cleaning methods effectively removed membrane foulants, resulting in total membrane flux recovery rates of higher than 96.5%. The conductive materials stimulated the enrichment and synergistic collaboration of acid-producing bacteria and methanogenic archaea.