Population dynamics of microbial species under high and low ammonia nitrogen in the alternate layer bioreactor landfill (ALBL) approach

Anaerobic landfill process is still believed to be a complex ecosystem due to the lack of knowledge on the functional activities of microbial species. This research sought to introduce a novel landfill bioreactor, named here as the alternate layer bioreactor landfill (ALBL) of fresh MSW (FW) and stabilized waste (CT) to avoid inhibitory conditions for the microbial species in anaerobic landfill. The stabilized waste layer in the bottom of landfill cell significantly changed microbial ecology of fresh MSW which in turn reduced the concentrations of NH4-N (29-31%) and VFAs (33-38%) in the ALBL approach, compared to fresh MSW disposal in sanitary landfill. The reduction of NH4-N favored early onset of methanogenesis within 6 weeks and methane (CH4) content of landfill gas increased from 11% to 40-50% (v/v), owing to the coexistence of Methanosarcinales (36-50%) and Methanomicrobiales (26-28%) archaea. The acetoclastic methanogenesis was achieved by reducing NH4-N toxicity in the ALBL.