重金属对硫酸盐还原菌影响

含重金属硫酸盐废水是我国工业水污染的突出问题,利用硫酸盐还原菌的生物去除重金属的方法具有投资少、成本低、能耗少、去除率高,没有二次污染等优点而成为研究的热点。文章以混合培混养物作为接种污泥,考察不同浓度的重金属离子(Cu2+、Cd2+、Ni2+、Hg2+)对硫酸盐还原菌(Sulfate reducing bacteria,SRB)的抑制作用。研究表明:10 mg/L的Cu2+、Cd2+和20 mg/L的Hg2+对SRB还原硫酸盐的影响较小,硫酸盐最大去除率可分别达到94.1%、94.6%、91.3%,与空白(93.9%)相近;20 mg/L的Cu2+对SRB的抑制最为强烈,硫酸盐最大还原率仅为48.2%,剩余金属离子(Cd2+、Ni2+、Hg2+)都分别随着浓度的增大而对SRB的抑制作用增强;相同浓度的重金属离子对SRB的抑制顺序为Ni2+>Cu2+>Cd2+>Hg2+,抑制浓度分别为10、20、30、60 mg/L。最后阐述了各个反应器中硫酸盐还原率最大时,(WCOD/WSO42-)与硫酸盐还原率的关系。

Effect of Heavy Metal on Sulfate Reducing Bacteria

This paper related to a bench scale experiment for treatment of wastewater containing both sulfate and heavy metals ions of Cu2+,Cd2+,Ni2+ and Hg2+ with emphasis on influences of heavy metals on sulfate-reduction bacteria(SRB)in the anaerobic activated sludge system(UASB reactor).The experiment presented the maximum sulfate reduction rates-all above 91%-when affected by Cu2+,Cd2+ and Hg2+ of limited concentrations respectively;the strongest inhibitory effect exerted by heavy metal ions,e.g.copper ion,when its concentration rose to as high as 20 mg/L,as a result,the sulfate reduction rate was brought down to 48.2%.According to the experiment,inhibitory rating of the above heavy metals was Ni >Cu>Cd>Hg.In addition,due to the fact that COD in the wastewater sample decreased when sulfate being removed,relationship between COD reduction and sulfate reduction rate (WCOD/WSO42-) was studied in this paper.