Study On Removal Of Typical Organic Micropollutants By Microorganism In Riverbank Filtration System

Technology to clean up water is becoming more important because of rising emissions of Organic micropollutants(OMPs),including medical drugs,pesticides,personal-care products and industrial products.Although the concentration of OMPs is usually in the lower range of ng/L-ug/L,it still attracts the attention of scholars due to its potential harm to aquatic organisms and human health.Riverbank filtration(RBF)is a low energy consumption and high efficiency water purification technology based on natural processes that remove pollutants from river water through a range of biochemical and physical effects occurring in a riparian soil infiltration system.The removal mechanism is mainly biodegradation driven by soil microorganism.The removal of OMPs by soil microorganisms has only been reported in laboratory,However,laboratory studies have caused problems such as underestimated removal effect of disturbed soil on OMPs and insufficient residence time for soil microbial community to adapt to OMPs.Removal of OMPs by RBF systems requires more field studies because the microbiome under field conditions is more representative,but there have been few reports of field studies.In addition,although many studies have screened and isolated a series of degrading bacteria genera capable of degrading typical OMPs through laboratory culture methods.However,it is still unclear which functional microorganisms in the RBF system at the field scale are capable of degrading typical OMPs,and how effective is this degradation.The characteristics of soil microbial community composition and microbial diversity in RBF system were analyzed by 16 S rRNA high-throughput sequencing.Finally,by combining the removal effect of the two typical pollutants with microbiological analysis,the removal effect of the RBF system on the two typical OMPs at the field scale is preliminarily discussed.The main research contents are as follows:(1)Solid phase extraction(SPE)combined with ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)was used to quantitatively determine the contents of sulfaethoxazole(SMX)and carbamazepine(CBZ)in the surface water and water extraction Wells of six sections in the upper,middle and lower reaches.The distribution characteristics of the two pollutants were analyzed.(2)Based on DNA extraction and 16 S rRNA sequencing technology,the characteristics of microbial community in the soil of the bank filtration system in the upper,middle and lower reaches of Fuhe River Basin were analyzed,and the characteristics of microbial community composition,microbial diversity and microbial richness in the soil of the bank filtration system were identified.At the phylum level,Proteobacteria,Chloroflexi,Acidobacteria,Actinobacteria and Rokubacteria dominate the soil microbial communities in the soil of RBF.(3)Soil microorganisms were analyzed at the genus level,and seven core microbial genera were found(relative abundance >1%),they include: Streptomyces spp.,Rhodococcus spp.,Ralstonia spp.,Nitrospira spp.,Gaiella spp.,Bacillus spp.,Acidothermus spp.Among them,Ralstonia spp.,Bacillus spp.are two typical sulfamethoxazole-degrading bacteria genera,Streptomyces spp.and Rhodococcus spp.are two typical carbamazepine-degrading bacteria genera.The removal effect of two typical organic micropollutants in the bank filtration system was related to the soil microorganism genus in the bank filtration system.The removal of two typical OMPs by the onshore filtration system at the field scale is preliminarily discussed.