接种率及尿素添加量对农村生活垃圾厌氧发酵产甲烷的影响

摘要

In order to study the effects of inoculation ratio and urea concentration on methane production of anaerobic digestion of rural do-mestic wastes(RDW), a set batch of anaerobic digestion experiments, which chose 3 levels of inoculums ratio(0.3, 0.5, 1.0)and 3 levels of urea concentration(1%, 3%,5%), were conducted. The performances of volatile fatty acids(VFA), biogas production, methane produc-tion were investigated, and also methane production was fitted with the modified Gomopertz model to assess the characteristics of the anaero-bic digestion. The results showed that under the same concentration of urea, the higher the inoculation ratio was, the more methane was pro-duced and the faster VFAs were decomposed. Under the same inoculation ratio, the methane production showed a trend of increasing at first and then decreasing as the urea concertation increased. According to the fitting results of Gompertz kinetic model, when the inoculation ratio was 1 and urea concentration was 3%, the anaerobic digestion had the best performance.The cumulative methane production(70 d)was 0.44 L·g-1 TS, and the lag phase was only 12 d.%为了解接种率及尿素添加量对农村生活垃圾厌氧发酵产甲烷的影响,选取3个水平的接种率(0.3、0.5、1.0)和3个水平的尿素添加量(1%、3%、5%)进行农村生活垃圾厌氧发酵实验.结果表明,在相同尿素添加量的条件下,接种率(0.3~1.0)越高越有利于甲烷产生,同时挥发性脂肪酸降解速率越快;而在相同接种率的条件下,随尿素添加量(1%~5%)的增加,甲烷产量呈先升高后降低的趋势.Gompertz动力学模型拟合结果表明,在接种率为1.0、尿素添加量为3%的条件下,厌氧发酵产甲烷延滞期较短(12 d),70 d累积甲烷产量最高(0.44 L·g-1 TS),发酵过程未发生酸化现象.