The Research On The Anaerobic Co-digestion Of The Food Waste And Landfill Leachate

The output of food waste in China increases rapidly in recent years. Using anaerobic digestion of food waste system to produce biogas has become an ideal choice to reduce environmental damage and waste of resources, but the single-phase anaerobic digestion of food waste is easy to cause acid suppression, which would seriously affect the effect of gas methane. Meanwhile, Landfill leachate is a kind of organic waste containing a rich blend of ammonia nitrogen. It has become one of the environmental problems because of the great amount and difficulty in degradation. The previous studies of our research group have shown that digesting these two combined with anaerobic can well solve the problem that single-phase anaerobic digestion of food waste easily get acidified. It can also improve the anaerobic performance of digestion and producing gas at the same time. The development of this technology has great application prospect, so the research of this paper is carried out.This study has adopted the method that adding concentrated solution into co-anaerobic digestion material liquid, observing the influence of the concentrated solution on the combined anaerobic digestion, thus further exploring the law of gas production and influence factors of anaerobic digestion. The total mass of material liquid is 1500 g, the ratios of activated sludge is 20%, the solid rate of food waste is 4%, digestion temperature of 35 ?. Under such condition of anaerobic digestion, by monitoring the digestive fluid p H, concentration of ammonia nitrogen, volatile fatty acids(VFAs), BOD5, CODcr and gas rate, cumulative gas production and gas composition changes in the process of combined anaerobic digestion as the indexes to analyze the stability of the system and anaerobic digestion performance.The experimental results show that :(1) In the first experiment, the concentrated solution affects combined anaerobic digestion process by promoting food waste hydrolysis. To for regulating fluid digestion jar of The acidification speed, gas rate, total volume and methane content of the digester using concentrated solution as regulating fluid were significantly higher than using water as regulating fluid. this showed that the concentration of concentrated liquid has a positive effect on the co-anaerobic digestion;(2) In the second experiment, the digester of the highest concentration of ammonia nitrogen had best gas production. The cumulative gas production reached 165% of the theoretical value of the single-phase, the highest volume in digestion appeared in the second day, 62l/d, anaerobic digestion of food waste, gas methane content remained above 60%;(3) It is feasible to combine the concentrated liquor and landfill leachate as digestive substrate to co-anaerobic digestion with food waste.