不同好氧预处理方式对餐厨垃圾产甲烷的影响

为了研究不同好氧预处理方式对餐厨垃圾厌氧消化产甲烷的影响,通过建立3个模拟厌氧生物反应器,研究了传统厌氧生物反应器C1、上层好氧预处理-厌氧生物反应器C2和底部好氧预处理-厌氧生物反应器C3 3种不同操作条件下的产甲烷过程。结果表明,挥发性有机酸的累积使C1始终处于产甲烷滞后阶段;而C2、C3的好氧预处理通过加快易水解酸化组分和过量挥发性有机酸的好氧降解,有效缓解了酸性抑制,产甲烷滞后时间明显缩短至10 d内。第32天C2停止上层曝气后,在27 d内甲烷浓度达到了50%以上,同时,产甲烷速率迅速上升,并在第81天可达到峰值773 mL/(kg·d)。C3在第11天停止底部曝气后,虽然经过22 d的时间甲烷浓度即上升至50%,但之后产甲烷速率经历回落阶段后再次逐渐上升,在实验结束时仅达到517 mL/(kg·d)。上层曝气的好氧预处理方式所需曝气时间相对较长,但其产甲烷启动快,与底部曝气相比,其后期的甲烷化过程更稳定并可达到较高的产甲烷速率。

Effects of different aerobic pretreatments on methane production from food waste

In order to study the effects of different aerobic pretreatments on methane production from food waste, three simulated anaerobic bioreactors were constructed, including traditional anaerobic bioreactor C1, upper-layer aerobic-anaerobic bioreactor C2 and bottom aerobic-anaerobic bioreactor C3. Results indicated that C1 was maintained at the lag-phase of methane production due to the accumulation of volatile fatty acids. However, the lag time of methane production in C2 and C3 could be reduced to less than 10 days. The aerobic pretreatment of C2 and C3 was capable to increase the aerobic degradation of easily hydrolysed fractions and the excess volatile fatty acids. After stopping upper layer aeration on the 32nd day, methane concentration of C2 could increase to above 50% within 27 days. And the methane production rate increased quickly, arriving to the peak value of 773 mL/(kg·d) on the 81st day. For C3, bottom aeration ceased on the 11st day, even though methane concentration reached to over 50% within 22 days, the subsequent methane production rate decreased before gradually increased again. The methane production rate in C3 could only achieve 517 mL/(kg·d). Upper-layer aerobic pretreatment might need relatively longer time, but the start-up of methane generation was accelerated. In addition, compared to bottom aerobic pretreatment, the subsequent methanogenesis process of upper-layer aerobic pretreatment was more stable and it could reach to higher methane production rate.