Treatment of municipal landfill leachate at different stabilization stages in two-stage membrane bioreactor bioaugmented with Alcaligenes faecalis no. 4

Abstract Organic and nitrogen removals in two-stage membrane bioreactor (2-stage MBR) applied to the treatment of fresh, mixed, and partially stabilized leachate at different concentrations were investigated. A pilot-scale 2-stage MBR system was operated at a different hydraulic retention time of 2.5 and 1 days during which organic loading rates were varied between 1.5 and 20.2 kg BOD/m3 d. The effect of Alcaligenes faecalis no.4 bio-augmentation and its survival during the treatment was examined. High organic and nitrogen removals (>90%) was achieved when the system was applied to fresh and mixed leachate with BOD/COD of 0.5-0.76 but the removals of COD, TKN was reduced to 58-70% and A. faecalis no.4 population became extinct when partially stabilized leachate was pre-treated and reduced its BOD/COD to 0.11. This study demonstrates the applicability of 2-stage MBR to the treatment of leachate with varied characteristics provided that its treatment conditions were properly adjusted.