微生物载体对MBBR工艺性能及微生物群落结构的影响

通过选用聚氨酯吸水凝胶(porous polymer carriers, PPC)、聚氨酯海绵(polyurethane, PU)、聚丙烯(polypropylene, PP)3种材质的微生物载体,对分别投加这3种载体的移动床生物膜反应器(MBBR)的启动性能、氮去除性能及微生物群落结构进行对比分析。结果表明:在进水氨氮浓度为20 mg/L的情况下,PPC及PU载体表现出较好的挂膜启动性能和氨氮去除性能,出水氨氮平均浓度在5 mg/L左右,而PP载体的出水氨氮平均浓度将近7 mg/L,且去除效果稳定性较差;此外PU载体和PP载体的反硝化效果不理想,出水硝态氮平均浓度分别为6.07,4.87 mg/L,比PPC载体(2.80 mg/L)高出许多。微生物测序结果表明,微生物载体的选择对MBBR工艺微生物群落结构有一定影响,但Proteobacteria和Bacteroidetes始终是占比最大的细菌门类。属水平的分析表明PPC载体上存在较高丰度的反硝化Denitratisoma菌属,且PPC载体独特的结构和亲水性有助于营造缺氧环境,提高反应器整体脱氮性能和稳定性。

EFFECTS OF MICROBIAL CARRIERS ON PERFORMANCE AND MICROBIAL COMMUNITY STRUCTURE OF MBBR

In this study, three kinds of microbial carriers including porous polymer carriers(PPC), polyurethane(PU) and polypropylene(PP) were selected to compare and analyze the start-up performance, nitrogen removal performance and microbial community structure of mobile bed biofilm reactor(MBBR) with three carriers respectively. The results showed that when the influent ammonia concentration was 20 mg/L, PPC and PU carriers showed better film-hanging start-up performance and ammonia nitrogen removal performance. The average effluent ammonia nitrogen concentration was about 5 mg/L, while the average effluent ammonia nitrogen concentration of PP carrier was nearly 7 mg/L, and the removal stability was poor. In addition, denitrification effect of PU and PP carrier was not ideal, and the average concentration of effluent nitrate nitrogen was 6.07, 4.87 mg/L, respectively, much higher than PPC carrier(2.80 mg/L). The microbial sequencing results showed that the selection of microbial carriers had a certain degree of influence on microbial community structure of the MBBR process, but Proteobacteria and Bacteroidetes were always the most dominant bacterial species. Analysis at the level of genus indicated that Denitratisoma bacteria with high abundance existed on PPC carrier, and the unique structure and hydrophilicity of PPC carrier contributed to the creation of anoxic environment, and improved the overall Denitratisoma performance and stability of the reactor where it was located.