生物电催化调控污泥-餐厨垃圾协同厌氧产酸研究

Microbial electrolysis cells and anaerobic digestion (MEC-AD) system was built up and the co-digestion of sewage sludge (SS) and food waste (FW) for volatile fatty acids (VFAs) production was conducted for 45 days to investigate the pattern of acidification under each FW: SS mixing ratio(VS: VS). The results showed that, under the applied voltage of 0.8 V, the stimulation of applied current could contribute to the growth of microorganisms, co-digestion efficiency and VFAs accumulation. The promotion became more obvious when the proportion of food waste was increased. The highest VFAs productivity was achieved under the mixing ratio of FW∶SS = 8∶2 and solid retention time of 7 d. The yield of acetic acid and propionic acid reached 164.7 mg·L^-1 and 102.4 mg·L^-1 respectively, and the acetic acid concentration was about 5.7 times of the control group. A large amount of isovaleric acid was produced simultaneously, with the yield of 176.1 mg·L^-1 at 38 d Under the optimal ratio, the generation of methane and carbon dioxide was evidently restrained, while hydrogen was stably produced in accordance with the trend of VFAs production. The scanning electron microscope (SEM) clearly observed the adhesion of dominant microorganisms and formation of complete biofilm. The enrichment of microorganisms on the electrode surface promoted the release of electrons and VFAs production. This study could provide some references for VFAs production and recovery and the underlying enhancement mechanisms of bio-electrochemical stimulation on metabolic efficiencies of sludge and food waste.