基于仿生学的一体式两相厌氧反应器的运行研究
The performance of an integrated two-phase anaerobic reactor based on bionics
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摘要: 反刍动物瘤胃对纤维素类物质具有强大的消化功能,在厌氧发酵领域备受关注。基于仿生学的原理,设计了一体式两相新型厌氧反应器,并以秸秆、猪粪和河道底泥为底物进行干式共发酵,研究了该反应器的水解酸化和产甲烷性能。结果表明,反应器在1~9 d的产气速率快,期间单位体积累积产气量增长速率为366.87 mL/(L·d),最快产气速率22.3 mL/(gVS·d);发酵过程累积产气量为0.13 L/g挥发性固体;发酵过程中pH在7.3~8.2间变化,pH与挥发性脂肪酸(VFAs)浓度整体上呈现相反的变化趋势,反应器内未发现氨抑制现象;在第1~21 d,主反应室产生的溶解性化学需氧量(SCOD)在次反应室中被充分利用,实现了水解过程和水解产物利用过程的分离;厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)是反应器中最丰富的两个菌门,均具有水解和产酸能力。基于瘤胃设计的反应器既具有不同水解程度底物分层和持续吸收VFAs的效果,又有上部水解和产酸、下部产甲烷的一体式两相厌氧发酵效果。该反应器可有效延长固体物质的停留时间,提高底物的水解酸化效率,减少反应器内局部酸抑制现象的发生。Abstract: Lignocellulosic biomass can be effectively digested in animal rumen, which makes rumen-derived anaerobic digestion as an attractive strategy. Based on the principles of bionics, this study designed an integrated two-phase anaerobic reactor, and investigated its hydrolysis acidification and methane-producing capability by feeding with straw, pig manure and river sediment as substrates. The results indicated that the biogas production rate in 1-9 d was fast and the increasing rate of cumulative gas production was 293.46 mL/(L·d), the fastest biogas production rate in this period was 22.3 mL/(gVS·d), and the cumulative gas production was 0.13 L/g volatile solid. The pH value ranged from 7.3 to 8.2, and showed an overall opposite variation trend with the concentration of volatile fatty acids (VFAs), indicating that ammonia inhibition did not occur in the reactor. Soluble chemical oxygen demand (SCOD) produced by main reaction chamber was substantially utilized in secondary reaction chamber in 1-22 d, realizing the separation of hydrolysis process and the utilization process of hydrolysis products. In the reactor, Firmicutes and Bacteroidetes were the two most abundant bacterial phylums, and had hydrolysis and acid-production capacity. The reactor had not only the effects of substrate stratification and continuous absorption of VFAs, but also upper hydrolysis and acid production, and lower methane production. Therefore, the reactor can effectively prolong the solid residence time, improve the hydrolysis and acidification efficiencies, and eliminate partial acid inhibition in the reactor.
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