贵州某废弃煤矿酸性废水处理系统中细菌群落结构及功能分析

Analysis of Bacterial Community Structure and Function in Acid Wastewater Treatment System of an Abandoned Coal Mine in Guizhou Province

煤矿酸性废水引起的水环境污染问题在贵州日益突出.以贵州某废弃煤矿酸性废水处理系统(碳酸盐岩反应介质)为研究对象,采用高通量测序MiSeq技术,分析该系统中细菌群落结构的沿程变化特征及其功能.结果表明:①变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)和蓝细菌门(Cyanobacteria)等广泛分布于反应系统,其中变形菌门和绿弯菌门为主要优势菌门,而蓝细菌门大多(90.95%)存在于反应池悬浮物中.②细菌群落结构受沉积物中重金属浓度影响,尤其Fe、Ni、As和Pb浓度的影响较为显著.细菌群落在系统前端(进水沟渠和反应池)和后端(沉淀池和人工湿地)存在明显差异,随反应系统处理进程,细菌α-多样性指数在沉积物中沿程增加.③废水中85%以上的Fe在多级复氧反应池中被去除,同时具备铁氧化能力的细菌〔披毛菌属(Gallionella)和Sideroxydans等〕和铁还原细菌〔地杆菌属(Geobacter)和红育菌属(Rhodoferax)等〕大多存在于多级复氧反应池沉积物中.④人工湿地对废水中Mn有很好的去除作用,湿地沉积物和植物根际土壤中铁锰氧化物富集生物土微菌属(Pedomicrobium)(8.38%±1.51%)和硝化螺旋菌属(Nitrospira)(14.75%±0.46%)丰度明显高于多级复氧反应池.研究显示,在以碳酸盐岩为主要反应介质的“多级复氧反应池+垂直流人工湿地”联合处理酸性矿山废水过程中,污染物去除机理除碳酸盐岩中和沉淀作用外,生物氧化和生物还原作用也值得关注.

The water environment pollution caused by acid mine drainage(AMD)has become more prominent in Guizhou.In this paper,an AMD treatment system(using carbonate rock as the reaction medium)of an abandoned coal mine in this area was selected to study the characteristics and functions of the bacterial community structure along the process direction through a high-throughput sequencing technology.The results showed that bacterial community in the system mainly was consisted of Proteobacteria,Chloroflexi and Cyanobacteria.Among of them,Proteobacteria and Chloroflexi were the dominant populations,and 90.95%of Cyanobacteria existed in the suspended matter in the reaction cell.The structure of bacterial community was affected by the concentration of heavy metals in sediment,and the influence of Fe,Ni,As and Pb was especially distinct.There were significant differences in bacterial communities between the front part(inlet and reaction cell)and the back part(sedimentation cell and constructed wetland)of the system.The bacterialα-biodiversity index in sediments increased along the processing flow direction.More than 85%of Fe was removed in multistage reaeration reaction cell.Meanwhile,it was found that iron oxidizing bacteria including Gallionella and Sideroxydans and iron reducing bacteria including Geobacter and Rhodoferax mainly existed in the sediment of the multistage reaeration reaction cell.Additionally,manganese(Mn)in acid wastewater could be removed well through the constructed wetland.Moreover,Pedomicrobium,which could accumulate iron and manganese oxides,was in wetland sediments and plant rhizosphere soil.The abundance of Pedomicrobium(8.38%±1.51%)and Nitrospira(14.75%±0.46%)was higher in constructed wetland than that in multi-stage reoxygenation reaction cell.When the process combining multistage reoxygenation cell with vertical flow constructed wetland with carbonate rock as the main reaction medium was applied to treat AMD,not only carbonate rock neutralization and precipitation but also biological oxidation and biological reduction all played important roles in the removal of pollutants in AMD.