Biomass growth and its mobility in an AnSBBR treating landfill leachate

This work used a pilot scale (with a total volume of 1300 L) Anaerobic Sequencing Batch Biofilm Reactor (AnSBBR) to treat landfill leachate from Sao Carlos-SP (Brazil) as well as to evaluate the biomass growth and its behavior. Biomass from the bottom of a landfill leachate stabilization pond was immobilized in polyurethane foam cubes as inoculum. The leachate characteristics varied during the experiment. Ethanol or volatile fatty acids were added as additional substrate when the leachate was temporarily recalcitrant. After acclimation, the AnSBBR presented efficiency over 70% (COD removal). A mass balance model, biomass sampling and temporal concentration profiles were performed to obtain a biomass yield coefficient of Y-x/s = 0.0251 +/- 0.0006 g(TVS) g(COD) (removed) (r(2) = 0.999). Additionally, it was observed that a variable fraction of the attached biomass may detach itself or present mobility during the batch time, however returning to fixed bed depending on the substrate type and concentration. This behavior has never been reported by the literature for attached biomass. (C) 2018 Elsevier Ltd. All rights reserved.