Multi-step sequential batch two-phase anaerobic composting of food waste

This study was conducted to evaluate the newly devised process, called h MU lti-step Sequential batch Two-phase Anaerobic Composting (MUSTAC). The MUST AC process consisted of several leaching beds for hydrolysis, acidification and post treatment, and a UASB reactor for methane recovery. This process to treat food waste was developed with a high-rate anaerobic composting tec hnique based on the rate-limiting step approach Rumen microorganisms were i noculated to improve the low efficiency of acidogenic fermentation. Both tw o-phase anaerobic digestion and sequential batch operation were used to con trol environmental constraints in anaerobic degradation. The MUSTAC process demonstrated excellent performance as it resulted ins large reduction in v olatile solids (VS) (84.7%) and high methane conversion efficiency (84.4%) at high organic loading rates (10.8 kg VS m(-3) d(-1)) in a short SRT (10 d ays). Methane yield was 0.27 m(3) kg(-1) VS, while methane gas production r ate was 2.27 m(3) m(-3) d(-1). The output from the post-treatment could be used as a soil amendment, which was produced at the same acidogenic ferment er without troublesome moving. The main advantages of the MUSTAC process we re simple operation and high efficiency. The MUSTAC process proved stable, reliable and effective in resource recovery as well as waste stabilization.