The Features Of Microbial Community In A~2/O Reators Treating The Mixture Of Landifill Leachate And Acid Mine Drainage

Acid mine drainage caused by mining process and landfill leachate generated from refuse landfill resulted in a serious secondary effects on the environment. The mixture were digested by biological treatment which could regulate the high concentration of sulfate, organic matter concentration and heavy metal ions concentration in wastewater. In this study, Anaerobic-Anoxic-Oxic(A2/O) were used to treat the mixture of AMD and landfill leachate. The sturcutre and evolution of microbial community in the reactors were investigated. The functional microorganisms were identified which were expected to reveale the relationship between reactor operation, influent characteric, microbial community and reactor performances. It was expected to provide meanful information for the treatment of AMD and landfill leachate. The main research contents and conclusions are listed as follows:(1) PCR-DGGE analysis results indicated that phylum Proteobacteria accounted for 46% of the total flora, and phylum Firmicutes accounted for 21.9% in the anaerobic reactor at the initial phase. Phylum Proteobacteria. accounted for 34.6% of the total flora, phylum Firmicutes accounted for 7.7% and phylum Thermotoga significantly improved accounted for 39% during its mid-term. In the later stage, bacterial phylum Firmicutes and phylum Bacteroidetes was significantly increased to a total amount of 60.4%. The bacteria methioned above in the reactor almost perform the function of hydrolysis acdification, and degradation of complex organic matter. The domain bacteria were phylum Proteobacteria and phylum Bacteroidetes in the aerobic and anoxic reactor, and the phylum Firmicutes grew in plenty in the later stages.(2) Clone libaray analysis results showed that the sample from landfill leachate owned 15 bacterial OTUs. In the anaerobic reactor sample,12 bacterial OTUs were detected. In the aerobic and anoxic samples, its 8 and 6 OTUs respectively. And phylum Proteobacteria, phylum Firmicutes and phylum Bacteroidetes were dominant bacteria.(3) The Illumina MiSeq sequencing system results of the four samples, phylum Proteobacteria, phylum Firmicutes and phylum Bacteroidetes were always dominant bacteria. They played a crucial role in anaerobic digestion and fermenting complex organic substance. In the anaerobic reactors, there were plenty of phylum Planctomycetes which contained various anaerobic ammonium oxidizing bacteria.(4) The Illumina MiSeq sequencing system results owned a higher sensitivity than the other two methods. It can be more comprenhensive and accurate to reflect the microbial community of the reactors. And the PCR-DGGE and clone library could only detect limited dominant microbial groups. The former is about 3-4 times sensitivity of PCR-DGGE and clone library. And the later massively underestimated the OTUs in the samples.