Study On The Effect Of Tail Water Discharged On Bacterial Community In River And Groundwater

To explore the influence of tail water discharged on bacterial community of river and groundwater.According to the tail water,river and groundwater in CHANGZHOU SHENSHUI CHENGBEI WASTEWATER TREATMENT CO.,LTD.as the research object in this paper.Water samples were collected.A total of 5 water quality indexes were measured for ammonia nitrogen(NH3-N),nitrate nitrogen(NO3--N),nitrite nitrogen(NO2--N),total nitrogen(TN)and total organic carbon(TOC),and the changes of water quality were studied.Analysis of bacterial communities by high-throughput sequencing technology and traditional microorganism culture technology.By comparing the changes of reference sites and experimental sites,the influence of tail water discharge on bacterial communities in river and groundwater was analyzed.The relationship between bacteria and water quality was discussed in depth.The analysis of the effect of tail water discharge on the bacterial community in river and groundwater could provide theoretical guidance for the control of water pollution and the rational utilization of water resources in this area.The main results research were followed:It were measured five indicators of water quality of tail water,river and groundwater on May and June,2016.The concentration of 5 water quality indexes was measured.The results showed that the discharge of tail water has a great influence on river.From May to June,nitrate nitrogen was significantly increased by 5.68 and 4.01 times,the concentration of total nitrogen increased by 3.61 and 1.27 times,and the concentration of nitrite nitrogen was significantly reduced by 0.91 times and 0.95 times(P < 0.05),respectively.The water quality of the tail water in July(summer),September(autumn)and December(winter)in 2016.The river were measured.The water quality changes in the river reference site and the experimental site were compared,and the effects of the tail water on river quality in different seasons were analyzed.The results showed that the concentration of nitrogen in surface water was significantly affected by tail water.From summer to winter,the concentration of nitrate nitrogen increased by5.65 times,2.49 times,0.90 times,respectively.The concentration of total nitrogen increased by 2.01 times,2.29 times,0.54 times,respectively,and the concentration oftotal organic carbon increased by 0.40 times in winter.From summer to winter,the concentration of ammonia nitrogen was significantly reduced by 0.67 times,0.49 times and 0.77 times,and the nitrite nitrogen concentration was significantly reduced by 0.90 times,0.64 times,0.86 times,respectively.Total nitrogen concentration decreased by0.25 times in summer(P < 0.05).The traditional culture technology was used to analyze the community structure of the culturable bacteria in the tail water,river and ground water around the factory on May and June,2016,and analyzed the effect of tail water on structure of the cultivated bacteria community in river and groundwater.By comparing the bacterial community structure of experimental site and reference site of river,the results showed that the relative abundance of Enterococcus and Paracoccus increased by 11.00 times and 6.23 times,and the relative abundances of Azotobacter decreased by 0.89 times in May.The relative abundance of Exiguobacterium and Xanthobacter increased by 6.00 times and4.00 times,respectively.The relative abundance of the Rhodococcus was reduced by0.67 times in June.By comparing the experimental site and reference site of groundwater,the bacterial community structure can be cultivated.The results showed that the relative abundance of Serratia increased by 1.61 times,and the relative abundances of the Ochrobactrum decreased by 0.83 times in May.the relative abundance of Azomonas and Corynebacterium increased by 2.99 times and 1.19 times respectively,and the relative abundances of Azatobacter decreased by 0.67 times in June.Through the above research results showed that tail water has greater influence on the community structure of culturable bacteria in river.In order to further analyze the effect of the tail water on the bacterial community in riverr in different seasons,the number of bacteria was calculated by the traditional microbiological culture technology in July(summer),September(autumn)and December(winter)in 2016 in tail water and river.The bacterial community structure and diversity were clearly defined by high-throughput sequencing technology.The changing rule of bacterial community structure and diversity in different seasons was analyzed.The results showed that a total of 355315 high-quality sequences were obtained,and 1679 OTU were generated.The bacteria belonged to 43 gates and 612 genera.Weighted Unifrac analysis showed that there were significant differences in community composition between upstream and downstream in tail water and river.Theamount of bacteria in river decreased significantly in winter(P < 0.05),the bacterial community structure and alpha diversity decreased in summer and autumn.The relative abundance of Pseudomonas,Sphingomonas and Acinetobacter who below the Proteobacteria was greatly influenced.The relative abundance of Pseudomonas and Sphingomonas increased in summer and decreased in winter,the relative abundance of Pseudomonas and Acinetobacte decreased in autumn.Correlation analysis between bacterial community and water quality index of tail water and river under different seasons was conducted.The results showed that a significant positive correlation between the number of bacteria and ammonia nitrogen concentration and nitrite nitrogen concentration(P < 0.05),but there was no significant correlation with the other water quality.There was no significant correlation between bacterial diversity and water quality.Total nitrogen has the strongest influence on the bacterial community.Ammonia nitrogen and nitrite nitrogen were positively correlated with Acinetobacter,Micrococcaceae and Hgcl_clad,but it were negatively correlated with Halomonas and Undibacterium.Total nitrogen and nitrate nitrogen was positively correlated with Halomonas and Undibacterium,but it was negatively correlated with Acinetobacter,Micrococcaceae and Hgcl_clad.Total organic carbon was negatively correlated with Parcubacteria.