An experimental study of bioclogging of aquifer media during artificial reinjection of groundwater

In the process of artificial recharge of groundwater, microorganisms play an important role in the blockage of aquifer media besides mechanical particle deposition and chemical precipitation.At present, however, biomass is the main research content to reflect the occurrence of bio-clogging in the process of recharge blockage, and there are few researches on the composition of microbial flora in the process of blockage.One-dimensional seepage test is carried out to examine the microbial blockage process in aquifer media.The temporal and spatial dynamic changes in permeability, index of nutrition salts and extracellular polymeric substances(EPS)of aquifer medium are analyzed.The high-throughput sequencing technique based on 16SrRNA is used to deeply analyze the diversity and structural characteristics of microbial community, and to reveal the characteristics and succession law of microbial community in the process of recharge blockage at the level of molecular.The results show that in the process of recharge, the permeability of aquifer media shows an obvious non-linear decreasing trend.In space, blockage mainly occurs on the surface of medium.In time, the permeability of each layer goes through four stages: stable fluctuation, rapid decrease, slow declines and smooth.The bacteria attached to aquifer media are mainly distributed in 28 phyla, 65 classes, 162 orders, 258 families, 425 genera and 767 species.The abundance, diversity and evenness of bacterial community are decreased.In terms of the structure and composition of flora, proteobacteria is the dominant phylum, followed by actinobacteria, and pseudomonas is the main dominant genus.There is an obvious succession of bacterial community structure attached to the medium.