This study examined the associations between dissolved organic matter（DOM） characteristics and potential nitrification occurrence in the presence of chloramine along a drinking water distribution system. High-perfor...This study examined the associations between dissolved organic matter（DOM） characteristics and potential nitrification occurrence in the presence of chloramine along a drinking water distribution system. High-performance size exclusion chromatography（HPSEC） coupled with a multiple wavelength detector（200–280 nm） was employed to characterise DOM by molecular weight distribution, bacterial activity was analysed using flow cytometry, and a package of simple analytical tools, such as dissolved organic carbon, absorbance at 254 nm, nitrate,nitrite, ammonia and total disinfectant residual were also applied and their applicability to indicate water quality changes in distribution systems were also evaluated. Results showed that multi-wavelength HPSEC analysis was useful to provide information about DOM character while changes in molecule weight profiles at wavelengths less than 230 nm were also able to be related to other water quality parameters. Correct selection of the UV wavelengths can be an important factor for providing appropriate indicators associated with different DOM compositions. DOM molecular weight in the range of 0.2–0.5 kDa measured at210 nm correlated positively with oxidised nitrogen concentration（r = 0.99）, and the concentrations of active bacterial cells in the distribution system（r = 0.85）. Our study also showed that the changes of DOM character and bacterial cells were significant in those sampling points that had decreases in total disinfectant residual. HPSEC-UV measured at210 nm and flow cytometry can detect the changes of low molecular weight of DOM and bacterial levels, respectively, when nitrification occurred within the chloraminated distribution system.展开更多
Nitrogen-cycling microorganisms play key roles at the intersection of microbiology and wastewater engineering.In addition to the well-studied ammonia oxidizing bacteria,nitrite oxidizing bacteria,heterotrophic denitri...Nitrogen-cycling microorganisms play key roles at the intersection of microbiology and wastewater engineering.In addition to the well-studied ammonia oxidizing bacteria,nitrite oxidizing bacteria,heterotrophic denitrifiers,and anammox bacteria,there are some other N-cycling microorganisms that are less abundant but functionally important in wastewater nitrogen removal.These microbes include,but not limited to ammonia oxidizing archaea(AOA),complete ammonia oxidation(comammox)bacteria,dissimilatory nitrate reduction to ammonia(DNRA)bacteria,and nitrate/nitrite-dependent anaerobic methane oxidizing(NO_(x)-DAMO)microorganisms.In the past decade,the development of high-throughput molecular technologies has enabled the detection,quantification,and characterization of these minor populations.The aim of this review is therefore to synthesize the current knowledge on the distribution,ecological niche,and kinetic properties of these“overlooked”N-cycling microbes at wastewater treatment plants.Their potential applications in novel wastewater nitrogen removal processes are also discussed.A comprehensive understanding of these overlooked N-cycling microbes from microbiology,ecology,and engineering perspectives will facilitate the design and operation of more efficient and sustainable biological nitrogen removal processes.展开更多
基金the Australian Research Council (ARC) for financial support of the Linkage Project 110100459 - Multi-scale Strategy to Manage Chloramine Decay and Nitrification in Water Distribution Systems
文摘This study examined the associations between dissolved organic matter（DOM） characteristics and potential nitrification occurrence in the presence of chloramine along a drinking water distribution system. High-performance size exclusion chromatography（HPSEC） coupled with a multiple wavelength detector（200–280 nm） was employed to characterise DOM by molecular weight distribution, bacterial activity was analysed using flow cytometry, and a package of simple analytical tools, such as dissolved organic carbon, absorbance at 254 nm, nitrate,nitrite, ammonia and total disinfectant residual were also applied and their applicability to indicate water quality changes in distribution systems were also evaluated. Results showed that multi-wavelength HPSEC analysis was useful to provide information about DOM character while changes in molecule weight profiles at wavelengths less than 230 nm were also able to be related to other water quality parameters. Correct selection of the UV wavelengths can be an important factor for providing appropriate indicators associated with different DOM compositions. DOM molecular weight in the range of 0.2–0.5 kDa measured at210 nm correlated positively with oxidised nitrogen concentration（r = 0.99）, and the concentrations of active bacterial cells in the distribution system（r = 0.85）. Our study also showed that the changes of DOM character and bacterial cells were significant in those sampling points that had decreases in total disinfectant residual. HPSEC-UV measured at210 nm and flow cytometry can detect the changes of low molecular weight of DOM and bacterial levels, respectively, when nitrification occurred within the chloraminated distribution system.
基金supported by the National Natural Science Foundation of China(Grant No.41701269)the National Key R&D Program of China(No.2019YFC0408800)the Fundamental Research Funds for the Central Universities(No.2020FZZX001-06).
文摘Nitrogen-cycling microorganisms play key roles at the intersection of microbiology and wastewater engineering.In addition to the well-studied ammonia oxidizing bacteria,nitrite oxidizing bacteria,heterotrophic denitrifiers,and anammox bacteria,there are some other N-cycling microorganisms that are less abundant but functionally important in wastewater nitrogen removal.These microbes include,but not limited to ammonia oxidizing archaea(AOA),complete ammonia oxidation(comammox)bacteria,dissimilatory nitrate reduction to ammonia(DNRA)bacteria,and nitrate/nitrite-dependent anaerobic methane oxidizing(NO_(x)-DAMO)microorganisms.In the past decade,the development of high-throughput molecular technologies has enabled the detection,quantification,and characterization of these minor populations.The aim of this review is therefore to synthesize the current knowledge on the distribution,ecological niche,and kinetic properties of these“overlooked”N-cycling microbes at wastewater treatment plants.Their potential applications in novel wastewater nitrogen removal processes are also discussed.A comprehensive understanding of these overlooked N-cycling microbes from microbiology,ecology,and engineering perspectives will facilitate the design and operation of more efficient and sustainable biological nitrogen removal processes.
