AnMBR处理剩余污泥与厨余共消化的效能研究

Study on the performance of AnMBR in treating the co-digestion of sewage sludge and food waste

构建了高固体厌氧膜生物反应器(AnMBR)工艺,考察了有机负荷(OLR)对AnMBR处理剩余污泥和厨余的影响与作用机制.当OLR为4gCOD/(L·d)时,产甲烷率可达(301.5±4.2)mLCH_(4)/gCOD_(fed),与高水解率(78.8%)和比产甲烷活性有关.OLR为4~8gCOD/(L·d)时,通过调整适宜的出水泵抽停时间比,实现了低膜污染速率(0.3kPa/d)下的稳定长效运行.经过物化清洗后,SEM-EDX分析表明膜基本可恢复初始形态,C、Fe、P等元素的含量显著降低.宏基因测序结果表明,在OLR为4gCOD/(L·d)时,Defluviitoga是优势细菌属,其相对丰度最高((45.1%),Methanosarcina为优势古菌属(76.9%).当OLR提升至8gCOD/(L·d),Methanothrix相对丰度显著增加至50.4%,为该阶段主要优势古菌属,古菌群落受OLR的影响较大;在高OLR条件下(11g COD/(L·d)),Methanoculleus的相对丰度逐步上升(0.7%增加到2.4%).宏基因测序结果表明高负荷下氢营养型产甲烷代谢活性受到抑制可能与K14126(mvhA)、K00205(fwdF,fmd)和K00125(fdhB)代谢通路占比的变化有关.适宜的OLR有利于构建稳定的群落结构和高效的厌氧共消化代谢途径,促进了有机物向甲烷的生物转化.

A high-solid anaerobic membrane bioreactor(AnMBR)process was developed to investigate the effects of organic loading rate(OLR)on the treatment of excess sludge and food waste.When the OLR was 4gCOD/(L·d),the methane yield reached(301.5±4.2)mLCH_(4)/gCOD_(fed),which was related to the high hydrolysis rate(78.8%)and specific methanogenic activity.When the OLR was 4~8gCOD/(L·d),a long-term stable operation at a low membrane fouling rate(0.3kPa/d)was achieved by adjusting the effluent pump operating mode.After physical and chemical cleaning,SEM-EDX analysis showed that the fouled membrane could be restored to the original form,and the contents of C,Fe,P and other elements were significantly reduced.Metagenomics sequencing showed that Defluviitoga was the dominant genus of bacteria when the OLR was 4gCOD/(L·d).Methanosarcina was the dominant archaea(76.9%).When the OLR increased to 8gCOD/(L·d),the relative abundance of Methanothrix improved significantly to 50.4%being the dominant archaea at this stage,and the archaea community was greatly affected by OLR variations.Under high OLR conditions(such as 11g COD/(L·d)),the relative abundance of Methanoculleus increased gradually(0.7%to 2.4%).The results of macrogene sequencing showed that the inhibition of hydrogen-trophic methanogenesis activity under high load may be related to the changes in the proportion of metabolic pathways of K14126(mvhA),K00205(fwdF,fmd)and K00125(fdhB).Selecting appropriate OLRs is conducive to establishing stable microbial community and efficient anaerobic co-digestion metabolic pathway,which promotes the bioconversion of organic wastes to methane.