A pilot study on integrated two-stage anaerobic digestion of food waste in an innovative dual-cylinder reactor
(2.Beijing Zhongyuan Energy Co., Ltd, Beijing, China 100083)
(3.Shifang Environmental Protection & Bio-energy Co., Ltd, Jinan, China 250101)
【Abstract】In this study, an innovative integrated two-stage (ITS) anaerobic reactor was designed and constructed in pilot scale. The integrated reactor used the dual-cylinder configuration to separate the acidogenic stage in inner cylinder with the methanogenic stage in outer cylinder. The reactor was operated for 184 days treating food waste with elevated organic loading rates (OLR) . The ITS reactor showed high efficiency and stability. In the stable operation stages, the organic load was 3.0 kgVS/ (m3·d), volumetric gas production rate reached an average of 1.69 m3/(m3·d) , and highest value was up to 2.72 m3/(m3·d); the gas production rate was 0.57 m3/(kgVS·d) , and the organic solids removal rate was 77.2%. Due to stage separation effect, pH value of outer cylinder was about 0.3–0.4 unit higher than that of inner cylinder, the average volatile fatty acids (VFAs) and soluble chemical oxygen demand (sCOD) concentration of outer cylinder was 25% and 23% lower than that of inner cylinder, respectively. The ITS anaerobic reactor realized the separation of acidogenic and methanogenic stages in one reactor. The inner acidogenic stage performed the hydrolysis and acidogenic steps and reduced the impact of acid accumulation on the outer methanogenic stage, which played a key role in the stable operation of the reactor.
【Keywords】 anaerobic digestion; food waste; integrated two-stage reactor; methanogensis;
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