温度对一体式厌氧流化床膜生物反应器运行效能及微生物群落结构的影响

Effect of Temperature on the Performance and Microbial Community Structure in an Integrated Anaerobic Fluidized-bed Membrane Bioreactor Treating Benzothiazole Wastewater

本研究采用一体式厌氧流化床膜生物反应器(integrated anaerobic fluidized-bed membrane bioreactor,IAFMBR)处理含苯并噻唑的高浓度合成废水,考察了温度变化(35、25和15℃)对反应器运行效能,膜污染情况和微生物群落结构的影响.结果表明,温度下降对反应器运行效能和膜污染情况产生不利影响.当温度从35℃下降到15℃时,COD去除率下降7.4%,苯并噻唑去除率下降49.2%,挥发酸总量上升225.66 mg·L^(-1),甲烷产率(以CH_4/CODremoved计)下降0.118 m^3·kg^(-1).膜污染周期从5.2 d下降到2.5 d.对于滤饼层而言,达到膜污染时,SMP(soluble microbial product)的质量浓度从42.47 mg·L^(-1)上升到70.62 mg·L^(-1),EPS(extracellular polymeric substance)的含量(以VSS计)从46.30 mg·g^(-1)上升到82.22 mg·g^(-1);对于混合液而言,SMP的质量浓度从36.46 mg·L^(-1)上升到69.35 mg·L^(-1),EPS的含量从47.47 mg·g^(-1)上升到81.63 mg·g^(-1).蛋白质是EPS和SMP的主要成分,约占总成分的80%.微生物群落结构表明,Firmicutes(厚壁菌门)和Chloroflexi(绿弯菌门)始终是最优势的菌门,占全部菌门相对丰度的42.6%~61.0%.随着温度的下降,优势菌属分别是Clostridium(13.7%),Levilinea(15.2%)和Lactococus(17.9%).产甲烷古菌的优势菌属始终是Methanosaeta.

An integrated anaerobic fluidized-bed membrane bioreactor（ IAFMBR） was applied to treat synthetic high-strength benzothiazole wastewater. This study investigated the effect of temperature on the performance,membrane fouling and microbial community structure of IAFMBR. The results showed that decreasing temperature had an adverse effect on the performance and the cycle of membrane fouling. When temperature declined from 35℃ to 15℃,the COD efficiency dropped 7. 4%,benzothiazole removal efficiency dropped 49. 2%,the accumulation of total VFAs increased 225. 66 mg·L^-1,and methane yield（ in CH_4/CODremoved）dropped 0. 118 m^3·kg^-1. The membrane fouling cycle shortened from 5. 2 d to 2. 5 d. For cake layer,the concentration of soluble microbial product（ SMP） increased from 42. 47 mg·L^-1 to 70. 62 mg·L^-1,and the extracellular polymeric substance（ EPS） content（ in VSS） increased from 46. 30 mg·g^-1 to 82. 22 mg·g^-1 when the TMP was 15 k Pa. For mixed liquor,the concentration of SMP increased from 36. 46 mg·L^-1 to 69. 35 mg·L^-1 and the EPS content increased from 47. 47 mg·g^-1 to 81. 63 mg·g^-1. Protein was the main component of EPS and SMP,and occurred in proportion of 80%. The microbial community structure showed that the dominant phyla were Firmicutes and Chloroflexi,which accounted for 42. 6%-61. 0% of the total relative abundance. The genera Clostridium（ 13. 7%）,Levilinea（ 15. 2%）,and Lactococus（ 17. 9%） dominated with decreasing temperatures. The dominant methanogen was Methanosaeta.