连续流厌氧动态膜混合发酵系统的优化及运行效能研究

Optimization and operation performance of continuous anaerobic dynamic membrane co-digestion system

为探究厌氧动态膜反应器进行厌氧混合发酵产甲烷的连续运行效能,以玉米秸秆(CS)和餐厨垃圾(FW)为混合基质,通过批次试验优化了厌氧发酵系统启动阶段的关键参数。在此基础上启动运行了连续流厌氧动态膜混合发酵系统并解析了该系统的运行效能和动态膜截留效能。结果表明:CS与FW的最优基质混合质量比(CS/FW)为2.399时甲烷产量最高;设定CS/FW=2.399,接种比由0.272逐渐增至1.019,相应的甲烷产量先增后降,接种比应不高于0.815。设定CS/FW为2.399,在有机负荷为10.86 g/(L·d)时,采用连续进料方式运行中温厌氧动态膜混合发酵系统,经过66 d的启动和连续运行,可获得稳定的甲烷产量(平均为1.68 L/(L·d)),且系统内无总挥发性脂肪酸(TVFA)累积,碱度和pH均在厌氧发酵适宜范围内。同时,在厌氧动态膜混合发酵系统运行过程中,动态膜形成后系统的出料浊度可稳定在100 NTU以下,动态膜固液分离效果好。

To explore the operation efficiency of continuous anaerobic dynamic membrane reactor for methane production by co-digestion,corn straw(CS)and food waste(FW)were used as mixed substrates,and the key parameters in the start-up stage of anaerobic digestion system were optimized through batch test.Then the continuous anaerobic dynamic membrane co-digestion system was started and operated,and the operation efficiency and dynamic membrane interception efficiency of the continuous anaerobic dynamic membrane co-digestion system were analyzed.The results indicated that the optimal substrate mixing mass ratio of CS and FW(CS/FW)was 2.399 with the highest methane production.Under the optimal CS/FW of 2.399,when the substrate to inoculation(S/I)ratio gradually increased from 0.272 to 1.019,the corresponding methane production first increased and then decreased,indicating the S/I ratio should not be higher than 0.815.Then,the mesophilic anaerobic dynamic membrane co-digestion system was continuously operated under the organic load of 10.86 g/(L·d)and CS/FW of 2.399.After 66 days of start-up and continuous operation,the co-digestion methane production system achieved stable mean methane production of 1.68 L/(L·d)without total volatile fatty acids(TVFA)accumulation.And the alkalinity and pH were both within the appropriate range of anaerobic digestion.Meanwhile,the turbidity could be stabilized at less than 100 NTU during the operation of anaerobic dynamic membrane co-digestion system after the formation of dynamic membrane,indicating that the dynamic membrane solid-liquid separation was good.