Cu^(2+)、Ag^(+)和Hg^(2+)冲击对好氧活性污泥胞外聚合物含量及组成的影响

The effect of Cu^(2+),Ag^(+) and Hg^(2+) impact on the content and composition of extracellular polymeric substances(EPS)from aerobic activated sludge

微生物产生的胞外聚合物可减小外来因素对微生物的危害,含有高浓度重金属离子的工业废水对活性污泥的影响较大。以好氧活性污泥作为研究对象,考察了不同浓度Cu^(2+)、Ag^(+)和Hg^(2+)冲击条件下LB-EPS(loosely-bound EPS)和TB-EPS(tightly-bound EPS)的变化特点。结果表明,在相同浓度条件下,3种重金属离子对LB-EPS和TB-EPS的影响程度由高至低的顺序为Hg^(2+)、Ag^(+)、Cu^(2+)。在一定浓度范围的Cu^(2+)、Ag^(+)、Hg^(2+)的冲击条件下,LB-EPS中各类有机物含量均呈逐渐上升的趋势,而TB-EPS中各类有机物含量则持续下降。两者的负相关性分析结果表明,LB-EPS中部分有机物含量的增大主要来源于TB-EPS中对应成分的溶解与释放。当重金属冲击浓度过高时,微生物细胞结构的完整性与新陈代谢功能会严重受损。

Extracellular polymeric substances(EPS)produced by microorganisms can protect them from the external threats,and industrial wastewater containing high concentration of heavy metal ions has a greater impact on activated sludge.With aerobic activated sludge as the research object,the change characteristics of LB-EPS(loosely-bound EPS)and TB-EPS(tightly-bound EPS)under impact conditions of different concentrations of Cu^(2+),Ag^(+)and Hg^(2+)are investigated.The results show that under the same concentration conditions,the order of influence of three heavy metal ions on LB-EPS and TB-EPS from high to low is Hg^(2+),Ag^(+),Cu^(2+).Under the impact conditions of Cu^(2+),Ag^(+)and Hg^(2+)in a certain concentration range,the content of various organic substances in LB-EPS gradually increases,while the content of various organic substances in TB-EPS continues to decline.The negative correlation analysis results show that the increase of some organic content in LB-EPS is mainly due to the dissolution and release of corresponding components in TBEPS.When the impact concentration of heavy metal is too high,the integrity of microbial cell structure and metabolic function will be seriously damaged.