Municipal solid waste degradation and landfill gas resources characteristics in self-recirculating sequencing batch bioreactor landfill

Abstract

Based on the degradation characteristics of municipal solid waste (MSW) in China, the traditional anaerobic sequencing batch bioreactor landfill (ASBRL) was optimized, and an improved anaerobic sequencing batch bioreactor landfill (IASBRL) was put forward on the basis of leachate self-recirculation. By monitoring MSW composition, leachate characteristics variation and landfill gas (LFG) generation, the effect of IASBRL was comparatively studied by simulation landfill. Based on the adjusting, scouring and carrying effects of leachate self-recirculation, IASBRL can rapidly decrease Eh value to about −500 mV and form a suitable biochemical environment for methanogens, which provides a precondition for stable cooperation between non-methanogens and methanogens. IASBRL can avoid the accumulation of organic acids, make VFA (volatile fatty acid) concentration and CODCr decrease along with the small range fluctuations, and form a stable decomposition-consumption synergy during MSW degradation, therefore, the hydrolysis rate of easy hydrolyze material reaches 71.2% in IASBRL. From the viewpoint of LFG resources in IASBRL, the cumulative LFG production increases to 2 327.0 L, CH4 mass fraction stabilizes at about 50%, and these provide a favorable precondition for LFG development.