Study On The Purification Characteristics And Bacterial Community Structures In Constructed Wetland Of The Liao River Conservation Area

Constructed wetland technology is a promising technology in the field of water treatment.With the rapid development of this technology,research on constructed wetlands has been carried out in many countries.However,there are few studies on large scale constructed wetlands in high latitude and winter cold climates.This paper comprehensively detected the temporal and spatial change of water quality,operation conditions and the removal of main pollutants substances(COD,NH4+-N)in Dongxiliaohe,Bajiazi,Zhaosutai,Panjin constructed wetlands which built in Liaohe Reserve.Three-dimensional excitation-emission matrix fluorescence spectroscopy and Illumina Miseq high-throughput sequencing were used to detect the composition origin in the soluble organic matter(DOM)in the water and the community structure and distribution of typical wetland microorganisms.All our results indicated that all the wetlands of the high latitudes study area runs well throughout the year,including the cold winter.The water quality met the Surface Water Environment Quality Standard which belongs to the worse than Grade V water quality.The soluble organic matter(DOM)in wetland water mainly comes from the metabolism and life activities of microorganisms in the wetland.The fluorescence index(f450/500)ranged from 1.7 to 2.Illumina Miseq high-throughput sequencing indicated that 794805763 bases,2007207 reads with the average length 395.976(bp)were obtained.50 phyla,130 classes,312 orders,592 families,1276 genera,2939 species and 9467 OTUs,were identified.Proteobacteria and its subgroups was the main group in all the samples.In cold climates,Hardy microorganism,such as Psychrobacter,occupy a certain proportion in each sample.In the phylum level,there are considerable differences in microbial community structure between large-scale constructed wetlands and pilot-scale constructed wetlands.In large-scale constructed wetlands,Proteobacteria and Bacteroidetes accounted for a larger percentage,while Proteobacteria and Firmicutes contribute a large proportion in pilot-scale constructed wetlands.There were significant differences in microbial community structure between wetland sediment samples and plant samples.Cyanobacteria had significant advantages in plant samples.Gemmatimonadetes is abundant in sediment samples,but barely occurs in plant samples.The abundance of Bacteroidetes in two samples was also different.