磺胺甲噁唑对序批式生物反应器脱氮性能及微生物群落的影响

研究了长期暴露条件下磺胺甲噁唑(SMX)对序批式生物反应器(SBR)脱氮性能及微生物群落的影响。结果表明:长期暴露于6 mg/L的SMX环境中,SBR对有机物和NH₄+-N的去除无明显变化。COD的平均去除率为(92.57±0.92)%,NH₄+-N的平均去除率达到(98.71±0.34)%;NO₂--N和NO₃--N的出水浓度随运行时间的增加而升高;在第104天时反应器比耗氧速率(SOUR)、比氨氧化速率(SAOR)、比亚硝酸盐氧化速率(SNOR)、比硝酸盐还原速率(SNRR)和比亚硝酸盐还原速率(SNIRR)较添加SMX前分别下降了23.33%、24.47%、28.29%、14.97%和15.81%。SMX的存在致使胞外聚合物(EPS)、松散型胞外聚合物(LB-EPS)和紧密型胞外聚合物(TB-EPS)及其中的蛋白质(PN)和多糖(PS)含量随运行时间的增长而增加,PN/PS呈上升趋势。活性氧(ROS)的生成量和乳酸脱氢酶(LDH)的释放量随运行时间的增长而增加。6 mg/L的SMX可使活性污泥微生物群落的丰富度降低,多样性升高,降低了变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)和γ-变形菌纲(Gammaproteobacteria)的相对丰度,从而影响了SBR的脱氮性能。

EFFECT OF SULFAMETHOXAZOLE ON NITROGEN REMOVAL AND MICROBIAL COMMUNITY OF SEQUENCING BATCH BIOREACTORS

The effects of long-term exposure to sulfamethoxazole (SMX) on nitrogen removal performance and microbial community in sequence batch bioreactor (SBR) were studied. The results showed that the removal effect of organic matter and NH₄+-N by SBR didn't change significantly after long-term exposure to a 6 mg/L SMX environment. The average removal rate of COD was (92.57±0.92)%, and that of NH₄+-N reached (98.71±0.34)%. The effluent concentrations of NO₂--N and NO₃--N increased with the increase in operation time. On the 104th day, the specific oxygen consumption rate (SOUR), specific ammonia oxidation rate (SAOR), specific nitrate oxidation rate (SNOR), specific nitrate reduction rate (SNRR), and specific nitrite reduction rate (SNIRR) decreased by 23.33%, 24.47%, 28.29%, 14.97% and 15.81%, compared with those before adding SMX. With the existence of SMX, the contents of extracellular polymeric substance (EPS), loosely bound extracellular polymeric substance (LB-EPS) and tightly bound extracellular polymeric substance (TB-EPS), protein (PN) and polysaccharide (PS) increased with the increase of operation time, and PN/PS showed an upward trend. The production of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) increased with the increase of running time. 6 mg/L SMX could reduce the richness and increase the diversity of the microbial community in activated sludge, and decrease the relative abundance of Proteobacteria, Chloroflexi, and Gammaproteobacteria, thus affecting the nitrogen removal performance of SBR.