温度对厌氧膜生物反应器处理生活污水效能的影响

Effect of temperature on the efficacy of anaerobic membrane bioreactors for domestic wastewater treatment

为探明温度对厌氧膜生物反应器处理实际生活污水效能的影响,本研究考察了在不同温度(25、20和15℃)及水力停留时间(hydraulic retention time,HRT)(12 h和8 h)下,AnMBR的产甲烷效能以及膜污染特性。结果表明,当温度为25℃时,COD去除率达到81.9%,最高甲烷产率为0.21 L·g^(−1)。20℃时,系统的厌氧消化性能与25℃相比差异不大,但当温度下降到15℃时,COD去除率为73.5%,最高甲烷产率只有0.08 L·g^(−1)。微生物群落分析结果表明,乙酸营养型是主要的产甲烷途径,随着温度降低乙酸营养型产甲烷菌的丰度明显减少,因此,产甲烷菌活性降低是导致15℃时反应器厌氧消化性能下降的主要原因。当温度为25℃,反应器在HRT为8 h的膜污染速率是HRT为12 h的31.33倍。因此,在较低的运行温度下,系统难以实现在低HRT的长期稳定运行。膜阻力分析结果表明随着温度的降低,膜孔的有机物堵塞阻力占总阻力的比例有所增大,这是由于低温下胞外聚合物的增加所导致的。COD平衡结果表明,溶解性甲烷的释放量与甲烷的溶解性以及出水通量的大小有关。

This study investigated the impact of temperature on the efficiency of an anaerobic membrane bioreactor(AnMBR)treating real domestic wastewater.Methanogenic efficacy and membrane fouling characteristics were evaluated at different temperatures(25,20,and 15℃)and hydraulic retention times(HRTs)(12 hours and 8 hours).Results showed that COD removal rate was 81.9%and the maximum methane yield was 0.21 L·g^(−1) by AnMBR at 25℃.The anaerobic digestion performance of AnMBR at 20℃was similar to that at 25℃.However,COD removal rate was 73.5%and the maximum methane yield was 0.08 L·g^(−1) at 15℃.Microbial community analysis indicated acetate as the primary methanogenic pathway,and decreased temperatures led to a significant decrease in the abundance of acetate-consuming methanogens.The decline in anaerobic digestion performance at 15℃was attributed to the diminished microbial activity of methanogens.At 25℃,the membrane fouling rate with an HRT of 8h was 30.33 times higher than 12h,highlighting challenges in achieving long-term stable operation at lower HRTs and temperatures.Membrane resistance analysis revealed an increase in organic matter blockage with decreasing temperature,potentially due to elevated extracellular polymer production.COD equilibrium results showed a correlation between dissolved methane release and both methane solubility and the effluent flux magnitude.