酸化冲击对低pH厌氧发酵系统性能的影响

为了研究酸化冲击对厌氧发酵有机废水能源回收系统的影响，利用自制的厌氧内循环反应器（anaerobic internal circulation reactor，AICR），以模拟糖蜜废水为底物，逐步提高进水容积负荷以模拟高容积负荷下出现的酸化冲击。研究了反应器酸化前后运行参数，并利用高通量测序检测了酸化后系统微生物群落结构。结果表明：酸化会导致颗粒污泥解体，产气速率和COD去除率下降，产甲烷活性严重抑制，同时发酵类型也发生转变。反应器酸化以后，发酵类型从丁酸型发酵类型转变为混合酸发酵类型，在进水负荷不变的情况下，总产气速率下降约50%，从2 100 mmol·（L·d）-1下降至1 056 mmol·（L·d）-1。酸化后的系统中，非产氢发酵细菌为优势细菌（54.7%），而产氢细菌所占比例较少（37.3%），未检测到产甲烷细菌。

Effect of acidification shock on performance of anaerobic fermentation system at low pH

The objective of this experiment is to investigate the effect of acidification shock on the performance of anaerobic fermentation systems for energy recovery from organic wastewater. Variations in detection parameters were systematically analyzed in an anaerobic internal circulation reactor (AICR) fed with synthetic molasses wastewater. Influent volume loading was increased step by step to simulate the emergence of acidification shock on a high-volume loading. After acidification shock was applied,high-throughput sequencing technology was used to analyze the structure of the microbial community. The results showed that acidification shock had a fatal effect on the system. Acidification caused reductions in total biogas production rate and COD removal rate,disintegrated the granular sludge,transformed the fermentation type,and completely inhibited methanogens. With the implementation of the acidification shock,butyric-type fermentation was transformed into mixed-acid fermentation,which has a lower hydrogen-producing capacity than that of butyric-type fermentation. Total biogas production rate was reduced by about 50% (from 2 100 mmol·(L·d)-1 to 1 056 mmol·(L·d)-1) under the circumstances of no change in influent volume loading. The result of the microbial community analysis showed that the percentage of non-hydrogen producing bacteria was 54.7%, whereas the percentage of hydrogen producing bacteria was only 37.7% in the system,and methane-producing bacteria were not detected after acidification.