重金属Cd胁迫对厌氧氨氧化颗粒污泥脱氮效能影响及机制的研究

Effect of Cd Stress on Nitrogen Removal Efficiency of Anaerobic Ammonia Oxidation Granular Sludge and Its Mechanism

以外源Cd^(2+)和厌氧氨氧化(Anammox)颗粒污泥为探究对象,构建了升流式污泥床反应器,调查了Cd^(2+)短期和长期暴露对Anammox颗粒污泥脱氮及污泥特性的影响。结果表明,短期影响中低浓度Cd^(2+)短期暴露对Anammox颗粒污泥脱氮影响不明显但长期暴露实验中降低了脱氮性能,而高浓度Cd^(2+)短期和长期暴露均降低生物脱氮性能。Cd^(2+)降低了污泥浓度和沉淀性,但提高了胞外聚合物(EPS)含量,尤其蛋白质含量。当Cd的质量浓度为9.0 mg/L,NH_(4)^(+)-N、NO2--N和TN的去除率分别下降至81.6%、79.5%和65.3%,总悬浮固体(TSS)下降至4.51 g/L,EPS含量提高至94.1~94.6 mg/g。微生物学分析表明,Cd^(2+)存在提高了微生物丰富度和多样性,降低了Planctomycetes、Chloroflexi和Proteobacteria与生物脱氮相关微生物的丰度。

Taking exogenous Cd^(2+)and anaerobic ammonia oxidation(Anammox)granular sludge as the research object,an upflow sludge bed reactor was constructed,and the effects of short-term and long-term Cd^(2+)exposure on Anammox granular sludge denitrification and sludge characteristics were investigated.The results showed that in the short-term effect,the short-term exposure of low concentration of Cd had no significant effect on the nitrogen removal of Anammox granular sludge,but the long-term exposure experiment reduced the nitrogen removal performance,while the short-term and long-term exposure of high concentration of Cd^(2+)both reduced the biological nitrogen removal performance.Cd^(2+)decreased the sludge concentration and sedimentation,but increased the content of extracellular polymer(EPS),especially protein.When the concentration of Cd^(2+)was 9.0 mg/L,the removal efficiency of NH_(4)^(+)-N,NO_(2)^(-)-N and TN decreases to 81.6%,79.5%and 65.3%respectively,the total suspended solids(TSS)decreases to 4.51 g/L,and the EPS content increases to 94.1~94.6 mg/g.Microbiological analysis showed that the presence of Cd increased the abundance and diversity of microorganisms,and decreased the abundance of Planctomycoetes,Chloroflexi,Proteobateria and microorganisms related to biological nitrogen removal.