低温下改良SBBR脱氮除磷效能及微生物种群研究

Nitrogen and Phosphorous Removal Performance and Microbial Community of Modified SBBR at Low Temperature

以SBBR高标准脱氮除磷系统为研究对象,考察了温度对该系统脱氮除磷效能及微生物种群的影响,提出了低温下SBBR系统高标准脱氮除磷的运行策略。结果表明,温度对系统的脱氮效能影响显著。当温度为10℃、COD负荷为0.82 kg(/m^(3)·d)时,系统对NH_(4)^(+)-N、TN的平均去除率分别为72.4%、70.1%,与温度为24℃时相比,去除率分别降低26.4%和26.1%;通过调整低温(10℃)下SBBR系统的运行工况及进水方式,可以有效强化SBBR脱氮除磷效能,在COD负荷为0.41 kg(/m^(3)·d)、运行工况为进水6 min—厌氧2 h—好氧9 h—缺氧3 h(二次进水)—好氧9 h—沉淀0.8 h—排水6 min条件下,对COD、NH_(4)^(+)-N、TN和PO_(4)^(3-)-P的去除率分别提高至95.3%、99.2%、95.9%、95.1%,出水水质达到《地表水环境质量标准》(GB 3838—2002)类Ⅳ类水标准。16S rRNA Amplicon高通量测序结果表明,温度对功能微生物种群结构的影响不显著,对脱氮除磷功能菌属的相对丰度影响显著。当温度由24℃降低至10℃时,硝化菌属Nitrospira、反硝化菌属Flavobacterium和Thermomonas、聚磷菌属Candidatus_Accumulibacter的相对丰度分别由1.47%、9.17%、6.27%、2.70%降至0.67%、2.66%、1.82%、0.30%;而异养硝化好氧反硝化菌属Pseudomonas、反硝化聚磷功能菌属Dechloromonas的相对丰度分别由0.07%、0.12%上升至1.05%、1.03%。

The effects of temperature on nitrogen and phosphorus removal efficiency and microbial community of a sequencing batch biofilm reactor(SBBR)under strict discharge standard were investigated,and the operational strategy for SBBR to achieve efficient nitrogen and phosphorus removal at low temperature was introduced.The temperature had a significant effect on the nitrogen removal efficiency of the system.When the temperature and COD loading rate were 10℃and 0.82 kg/(m^(3)·d),the average removal efficiencies of NH_(4)^(+)-N and TN were 72.4%and 70.1%,respectively,which decreased by 26.4%and 26.1%compared with those at 24℃.The removal efficiency of nitrogen and phosphorus was effectively enhanced by adjusting the operating condition and feeding mode of the SBBR at low temperature(10℃).When the operating conditions were as follows:COD loading rate of 0.41 kg/(m^(3)·d)and cyclic time consisting of filling(6 min),anaerobic reaction(2 h),aerobic reaction(9 h),anoxic reaction(3 h,secondary filling),aerobic reaction(9 h),settling(0.8 h)and drainage(6 min),the removal efficiencies of COD,NH_(4)^(+)-N,TN and PO_(4)^(3-)-P increased to 95.3%,99.2%,95.9%and 95.1%,respectively,and the effluent quality met the classⅣcriteria specified in Environmental Quality Standards for Surface Water(GB 3838-2002).The 16S rRNA Amplicon high-throughput sequencing indicated that temperature had no significant effect on the microbial community composition,but had a significant effect on the relative abundance of denitrifying and phosphorous accumulating genera.When the temperature decreased from 24℃to 10℃,the relative abundance of Nitrospira(nitrifying bacterium),Flavobacterium,Thermomonas(denitrifying bacteria)and Candidatus_Accumulibacter(phosphorous accumulating bacterium)decreased from 1.47%,9.17%,6.27%and 2.70%to 0.67%,2.66%,1.82%and 0.30%,respectively.In contrast,the relative abundance of Pseudomonas(heterotrophic nitrification and aerobic denitrification bacterium)and Dechloromonas(denitrifying phosphorus accumulating bacterium)increased from 0.07%and 0.12%to 1.05%and 1.03%,respectively.