Study On Anaerobic Co-Digestion Of Feces, Kitchen Residue And Reed

A large amount of feces, kitchen residue and reed produces every year, and as the main wastes with high-organic have became one of the key environmental problems. Anaerobic digestion has proved an effective way to carry out reduction and harmlessness of feces, kitchen residue and reed wastes; moreover it can produce clean energy production.Anaerobic co-digestion of feces, kitchen residue and reed, which are the main organic waste and kept at mesophilic temperature(36±1℃),7% total solid content, was investigated.Firstly, the ratio of anaerobic co-digestion of feces, kitchen residue and reed was investigated. The results show that:the influence of materials on anaerobic digestion was that kitchen residue> reed> feces, and the influence of kitchen residue was highly significant, feces and reed were not significant. Appropriate additives of feces, kitchen residue and reed were 160g,60g and 50g respectively, orthogonal experiments show that the best proportion of anaerobic digestion of reed, feces and kitchen residue was 1:3.5:2. In addition to the group, which influence of kitchen residue on anaerobic co-digestion was investigated, each group did not appear acidification, with high COD removal efficiency and COD value of the fermentation liquor was between 1000-2000 mg/L. During the process of anaerobic co-digestion, increase trend of NH3-N concentration was found. However, anaerobic co-digestion inhibition was not observed. The reactors were in good airtight condition for NO3--N concentration increased firstly and then decreased.The effects of three different kinds of inorganic additives (diatomite, bentonite, zeolite) on anaerobic co-digestion of feces, kitchen residue and reed, which are the main organic waste, was investigated, and the accelerative mechanism about the anaerobic co-digestion with the addition of inorganic additives was also briefly discussed. The results showed that kept at mesophilic temperature(36±1℃),7% total solid content, each one of the three inorganic additives had positive effects on anaerobic co-digestion of the three kinds of materials, the sequence of improvement efficiency was:zeolite> diatomite> bentonite, when anaerobic co-digestion of additives were all 5%, Ca2+ and Mg2+ released from zeolite could be utilized effectively of by the microorganisms in digestive system, which promoted the effect of zeotic. Appropriate additives of zeolite, diatomite and bentonite were 10%,5%and 10% (W/W substrate), respectively. During the process of anaerobic co-digestion, each group, which three different kinds of additives was put in respectively, did not appear acidification, with COD removal efficiency being up to more than 70%, and increase trend of NH3-N concentration was found. However, anaerobic co-digestion inhibition was not observed. The addition of zeolite resulted in significant NH3-N removals better than bentonite and diatomite.