秸秆干式厌氧发酵渗滤液回流技术研究

采用室内模拟试验方法，研究了秸秆干式厌氧发酵渗滤液回流量、回流方式对产气量的影响，分析比较了渗滤液的COD、VFA、pH变化以及其与产气率的相互关系。结果表明，在中温、底物浓度（TS）为18%条件下，发酵培养43 d，以0、0.2、0.4、0.6、0.8 L·d^-1的量回流，不同回流量处理间累积产气量差异不显著。底物浓度为20%、发酵84 d条件下，每天回流与产气趋势下降后回流以及两相法回流其总产气量较不回流对照分别提高了9.53%、23.13%、12.74%，其中以产气趋势下降后再回流的方式为最优。

Technique on Recycle of Leachate in Biogas Production from Rice Straw with Dry Anaerobic Digestion

The rice straw can be used for production of biogas. The recycle of the leachate may enhance the rate of biogas production for rice straw with dry anaerobic digestion. The effects of different leaehate recycle volumes and methods on biogas production from rice straw with dry anaerobic digestion were investigated. There was no obvious difference in the cumulated biogas production among the leachate recycle volumes （0, 0.2, 0.4, 0.6, 0.8 L·d^-1） in room temperature after 43 days of anaerobic digestion. In contrast, there were marked differences in the biogas production among the different leachate recycle methods. The rates of biogas production with dry anaerobic digestion in room temperature and 20% TS after 84 days were increased by 9.53% for the recycle everyday, 23.13% for the recycle while biogas production decreasing and 12.74% for the recycle using two-phase method compared to no-recycle. The changes of COD, VAS and pH in leachate were consistent with the rates of biogas production in different leachate recycle methods. The contents of degradated cellulose, hemicelluloses and lignin in rice straw were the highest in the leachate recycle while biogas production decreasing, followed by the recycle using two-phase method, the recycle everyday and no-recycle. Hence, the recycle of leachate while the rate of biogas production decreasing could maximumly enhance the biogas production and degradation of cellulose for rice straw using dry anaerobic digestion.