The nirS-type denitrifying bacterial community is the main drivers of the nitrogen loss process in drinking water reservoir ecosystems.The temporal patterns in nirS gene abundance and nirS-type denitrifying bacterial ...The nirS-type denitrifying bacterial community is the main drivers of the nitrogen loss process in drinking water reservoir ecosystems.The temporal patterns in nirS gene abundance and nirS-type denitrifying bacterial community harbored in aerobic water layers of drinking water reservoirs have not been studied well.In this study,quantitative polymerase chain reaction(qPCR)and Illumina Miseq sequencing were employed to explore the nirS gene abundance and denitrifying bacterial community structure in two drinking water reservoirs.The overall results showed that the water quality parameters in two reservoirs had obvious differences.The qPCR results suggested that nirS gene abundance ranged from(2.61±0.12)×10^(5) to(3.68±0.16)×10^(5) copies/mL and(3.01±0.12)×10^(5) to(5.36±0.31)×10^(5) copies/mL in Jinpen and Lijiahe reservoirs,respectively.The sequencing results revealed that Paracoccus sp.,Azoarcus sp.,Dechloromonas sp.and Thauera sp.were the dominant genera observed.At species level,Cupriavidus necator,Dechloromonas sp.R-28400,Paracoccus denitrificans and Pseudomonas stutzeri accounted for more proportions in two reservoirs.More importantly,the co-occurrence network analysis demonstrated that Paracoccus sp.R-24615 and Staphylococcus sp.N23 were the keystone species observed in Jinpen and Lijiahe reservoirs,respectively.Redundancy analysis indicated that water quality(particularly turbidity,water temperature,pH and Chlorophyll a)and sampling time had significant influence on the nirS-type denitrifying bacterial community in both reservoirs.These results will shed new lights on exploring the dynamics of nirS-type denitrifying bacteria in aerobic water layers of drinking water reservoirs.展开更多
Reservoirs have been served as the major source of drinking water for dozens of years.The water quality safety of large andmedium reservoirs increasingly becomes the focus of public concern.Field test has proved that ...Reservoirs have been served as the major source of drinking water for dozens of years.The water quality safety of large andmedium reservoirs increasingly becomes the focus of public concern.Field test has proved that water-lifting and aeration system(WLAS)is a piece of effective equipment for in situ control and improvement of water quality.However,its intrinsic bioremediation mechanism,especially for nitrogen removal,still lacks in-depth investigation.Hence,the dynamic changes inwater quality parameters,carbon source metabolism,species compositions and co-occurrence patterns ofmicrobial communitieswere systematically studied in Jinpen Reservoir within a wholeWLAS running cycle.TheWLAS operation could efficiently reduce organic carbon(19.77%),nitrogen(21.55%)and phosphorus(65.60%),respectively.Biolog analysis revealed that the microbialmetabolic capacitieswere enhanced viaWLAS operation,especially in bottomwater.High-throughput sequencing demonstrated that WLAS operation altered the diversity and distributions of microbial communities in the source water.The most dominant genus accountable for aerobic denitrification was identified as Dechloromonas.Furthermore,network analysis revealed that microorganisms interacted more closely through WLAS operation.Oxidation-reduction potential(ORP)and total nitrogen(TN)were regarded as the two main physicochemical parameters influencing microbial community structures,as confirmed by redundancy analysis(RDA)and Mantel test.Overall,the results will provide a scientific basis and an effective way for strengthening the in-situ bioremediation of micro-polluted source water.展开更多
Due to frequent drinking water pollution accidents in the past decade, it is common that mountain reservoirs were used as the source of drinking water in China. However, some coastal areas frequently suffer from typho...Due to frequent drinking water pollution accidents in the past decade, it is common that mountain reservoirs were used as the source of drinking water in China. However, some coastal areas frequently suffer from typhoon with extreme precipitation, which results in the water quality deterioration of the reservoirs. The influence of typhoons with extreme precipitation on Jiaokou reservoir and the emergency treatment process of Maojiaping water treatment plant in the past three typical typhoons with extreme precipitation from the year of 2012-2015 were studied. It was found that the degradation of water quality, such as the increase of turbidity and bacteria index, may not merely appear during the events, but last for several days. Changing the dosage of water purification agent, such as coagulant and disinfectant at right time and place may be an efficient emergency water treatment process. Based on the analysis of water quality variation rule during and after the events, it was also found that emergency treatment can be fully prepared before the arrival of a typhoon with extreme precipitation. And in order to better respond to the typhoon with extreme precipitation, several suggestions are also proposed in this paper as follows: establishing vegetated buffers at right place, such as macrophanerophytes,shrub or herbage, increasing investments in infrastructure management, merging or cancelling the small-scale water treatment plants, preparing adequate water purification agent before the typhoon comes, etc.展开更多
Based on field detected water quality data, the distribution characteristics of different forms of nitrogen in a reservoir as drinking water source in Dongguan, which locates at the Pearl River Delta of China, have be...Based on field detected water quality data, the distribution characteristics of different forms of nitrogen in a reservoir as drinking water source in Dongguan, which locates at the Pearl River Delta of China, have been analyzed in order to provide theoretical bases for prevention and reduction of eutrophication. The analyzed results show that nitrogen forms in the influent area of the reservoir are given priority to ammonia nitrogen and nitrate nitrogen, whose proportion is more than 45% respectively, and this is probably caused by the pollution of inflow water quality;but in the effluent area, the forms are given priority to nitrate nitrogen, whose proportion is as high as 96% and above;also the proportion of ammonia nitrogen drops by more than 80% during the process from the influent area to the effluent area, and this shows that the natural process of nitrification and denitrification can be well accomplished in the reservoir. We recommend here that to reduce the input amount of ammonia nitrogen and organic nitrogen into the reservoir is the most efficient way to prevent or mitigate eutrophication of water body.展开更多
In this study, the enclosure system exhibited perfect nitrogen removal performance with in situ oxygen-enhanced indigenous aerobic denitrifying bacteria in an enclosure experiment. We explored changes in the microbial...In this study, the enclosure system exhibited perfect nitrogen removal performance with in situ oxygen-enhanced indigenous aerobic denitrifying bacteria in an enclosure experiment. We explored changes in the microbial community during the nitrogen removal process using the MiSeq high-throughput sequencing technology. The results revealed a total of 7974 and 33653 operational taxonomic units(OTUs) for water and sediment systems, respectively, with 97% similarity. The OTUs were found to be affiliated with eight main phyla(Proteobacteria, Actinobacteria, Cyanobacteria, Bacteroidetes, Planctomycetes, Chloroflexi, Firmicutes, and Actinobacteria). The diversity of the enhanced system was found to be higher than that of the control system. Principal component analysis(PCA) revealed that significant spatial and temporal differences were exhibited in the microbial community during nitrogen removal in the enclosure experiment. Redundancy analysis(RDA)indicated that physical parameters(temperature, dissolved oxygen, and pH), nitrogen(total nitrogen and nitrate), functional genes(nirK and nirS), and dissolved organic carbon(DOC) were the most important factors affecting bacterial community function and composition. Lastly, the results suggested that the variation in the microbial community could be analyzed through the MiSeq high-throughput sequencing technology,which may provide technical support for future field tests.展开更多
基金supported by the National Nature Science Foundation of China (Nos. 51979217, 51978561)grant from Youth Innovation Team of Shaanxi Universities in 2020 (PI: Dr. Haihan Zhang)
文摘The nirS-type denitrifying bacterial community is the main drivers of the nitrogen loss process in drinking water reservoir ecosystems.The temporal patterns in nirS gene abundance and nirS-type denitrifying bacterial community harbored in aerobic water layers of drinking water reservoirs have not been studied well.In this study,quantitative polymerase chain reaction(qPCR)and Illumina Miseq sequencing were employed to explore the nirS gene abundance and denitrifying bacterial community structure in two drinking water reservoirs.The overall results showed that the water quality parameters in two reservoirs had obvious differences.The qPCR results suggested that nirS gene abundance ranged from(2.61±0.12)×10^(5) to(3.68±0.16)×10^(5) copies/mL and(3.01±0.12)×10^(5) to(5.36±0.31)×10^(5) copies/mL in Jinpen and Lijiahe reservoirs,respectively.The sequencing results revealed that Paracoccus sp.,Azoarcus sp.,Dechloromonas sp.and Thauera sp.were the dominant genera observed.At species level,Cupriavidus necator,Dechloromonas sp.R-28400,Paracoccus denitrificans and Pseudomonas stutzeri accounted for more proportions in two reservoirs.More importantly,the co-occurrence network analysis demonstrated that Paracoccus sp.R-24615 and Staphylococcus sp.N23 were the keystone species observed in Jinpen and Lijiahe reservoirs,respectively.Redundancy analysis indicated that water quality(particularly turbidity,water temperature,pH and Chlorophyll a)and sampling time had significant influence on the nirS-type denitrifying bacterial community in both reservoirs.These results will shed new lights on exploring the dynamics of nirS-type denitrifying bacteria in aerobic water layers of drinking water reservoirs.
基金This work was supported by the National Key Research and Development Program of China(No.2019YFD1100101)the National Natural Science Foundation of China(No.51979217)+2 种基金the Shaanxi Provincial Key Research and Development Program(No.2019ZDLSF06-03)the Youth Innovation Team of Shaanxi Universities in 2020(PI:Dr.Haihan Zhang)the Youth Innovation Team of Shaanxi Universities in 2021(No.21JP061).
文摘Reservoirs have been served as the major source of drinking water for dozens of years.The water quality safety of large andmedium reservoirs increasingly becomes the focus of public concern.Field test has proved that water-lifting and aeration system(WLAS)is a piece of effective equipment for in situ control and improvement of water quality.However,its intrinsic bioremediation mechanism,especially for nitrogen removal,still lacks in-depth investigation.Hence,the dynamic changes inwater quality parameters,carbon source metabolism,species compositions and co-occurrence patterns ofmicrobial communitieswere systematically studied in Jinpen Reservoir within a wholeWLAS running cycle.TheWLAS operation could efficiently reduce organic carbon(19.77%),nitrogen(21.55%)and phosphorus(65.60%),respectively.Biolog analysis revealed that the microbialmetabolic capacitieswere enhanced viaWLAS operation,especially in bottomwater.High-throughput sequencing demonstrated that WLAS operation altered the diversity and distributions of microbial communities in the source water.The most dominant genus accountable for aerobic denitrification was identified as Dechloromonas.Furthermore,network analysis revealed that microorganisms interacted more closely through WLAS operation.Oxidation-reduction potential(ORP)and total nitrogen(TN)were regarded as the two main physicochemical parameters influencing microbial community structures,as confirmed by redundancy analysis(RDA)and Mantel test.Overall,the results will provide a scientific basis and an effective way for strengthening the in-situ bioremediation of micro-polluted source water.
基金supported by the National Science Foundation of China(NSFC)(grant number 51438006)Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Due to frequent drinking water pollution accidents in the past decade, it is common that mountain reservoirs were used as the source of drinking water in China. However, some coastal areas frequently suffer from typhoon with extreme precipitation, which results in the water quality deterioration of the reservoirs. The influence of typhoons with extreme precipitation on Jiaokou reservoir and the emergency treatment process of Maojiaping water treatment plant in the past three typical typhoons with extreme precipitation from the year of 2012-2015 were studied. It was found that the degradation of water quality, such as the increase of turbidity and bacteria index, may not merely appear during the events, but last for several days. Changing the dosage of water purification agent, such as coagulant and disinfectant at right time and place may be an efficient emergency water treatment process. Based on the analysis of water quality variation rule during and after the events, it was also found that emergency treatment can be fully prepared before the arrival of a typhoon with extreme precipitation. And in order to better respond to the typhoon with extreme precipitation, several suggestions are also proposed in this paper as follows: establishing vegetated buffers at right place, such as macrophanerophytes,shrub or herbage, increasing investments in infrastructure management, merging or cancelling the small-scale water treatment plants, preparing adequate water purification agent before the typhoon comes, etc.
文摘Based on field detected water quality data, the distribution characteristics of different forms of nitrogen in a reservoir as drinking water source in Dongguan, which locates at the Pearl River Delta of China, have been analyzed in order to provide theoretical bases for prevention and reduction of eutrophication. The analyzed results show that nitrogen forms in the influent area of the reservoir are given priority to ammonia nitrogen and nitrate nitrogen, whose proportion is more than 45% respectively, and this is probably caused by the pollution of inflow water quality;but in the effluent area, the forms are given priority to nitrate nitrogen, whose proportion is as high as 96% and above;also the proportion of ammonia nitrogen drops by more than 80% during the process from the influent area to the effluent area, and this shows that the natural process of nitrification and denitrification can be well accomplished in the reservoir. We recommend here that to reduce the input amount of ammonia nitrogen and organic nitrogen into the reservoir is the most efficient way to prevent or mitigate eutrophication of water body.
基金supported by the National Science and Technology Pillar Program(Grant No.2012BAC04B02)the National Natural Science Foundation of China(Grant No.51478378)
文摘In this study, the enclosure system exhibited perfect nitrogen removal performance with in situ oxygen-enhanced indigenous aerobic denitrifying bacteria in an enclosure experiment. We explored changes in the microbial community during the nitrogen removal process using the MiSeq high-throughput sequencing technology. The results revealed a total of 7974 and 33653 operational taxonomic units(OTUs) for water and sediment systems, respectively, with 97% similarity. The OTUs were found to be affiliated with eight main phyla(Proteobacteria, Actinobacteria, Cyanobacteria, Bacteroidetes, Planctomycetes, Chloroflexi, Firmicutes, and Actinobacteria). The diversity of the enhanced system was found to be higher than that of the control system. Principal component analysis(PCA) revealed that significant spatial and temporal differences were exhibited in the microbial community during nitrogen removal in the enclosure experiment. Redundancy analysis(RDA)indicated that physical parameters(temperature, dissolved oxygen, and pH), nitrogen(total nitrogen and nitrate), functional genes(nirK and nirS), and dissolved organic carbon(DOC) were the most important factors affecting bacterial community function and composition. Lastly, the results suggested that the variation in the microbial community could be analyzed through the MiSeq high-throughput sequencing technology,which may provide technical support for future field tests.
