Li D.,CAS Research Center for Eco Environmental Sciences |
Li Z.,CAS Research Center for Eco Environmental Sciences |
Yu J.,CAS Research Center for Eco Environmental Sciences |
Cao N.,Water Quality Monitoring Center |
And 2 more authors.
Applied and Environmental Microbiology | Year: 2010
The role of bacteria in the occasional emergence of red water, which has been documented worldwide, has yet to be determined. To better understand the mechanisms that drive occurrences of red water, the bacterial community composition and the relative abundance of several functional bacterial groups in a water distribution system of Beijing during a large-scale red water event were determined using several molecular methods. Individual clone libraries of the 16S rRNA gene were constructed for three red water samples and one sample of normal water. Beta-, Alpha-, and Gammaproteobacteria comprised the major bacterial communities in both red water and normal water samples, in agreement with previous reports. A high percentage of red water clones (25.2 to 57.1%) were affiliated with or closely related to a diverse array of iron-oxidizing bacteria, including the neutrophilic microaerobic genera Gallionella and Sideroxydans, the acidophilic species Acidothiobacillus ferrooxidans, and the anaerobic denitrifying Thermomonas bacteria. The genus Gallionella comprised 18.7 to 28.6% of all clones in the three red water libraries. Quantitative real-time PCR analysis showed that the 16S rRNA gene copy concentration of Gallionella spp. was between (4.1 ± 0.9) × 107 (mean ± standard deviation) and (1.6 ± 0.3) × 108 per liter in red water, accounting for 13.1% ± 2.9% to 17.2% ± 3.6% of the total Bacteria spp. in these samples. By comparison, the percentages of Gallionella spp. in the normal water samples were 0.1% or lower (below the limit of detection), suggesting an important role of Gallionella spp. in the formation of red water. Copyright © 2010, American Society for Microbiology.
Wang Y.-R.,Jilin University |
Wang Y.-R.,Changchun University of Technology |
Li W.-Y.,Water Quality Monitoring Center |
Zhou B.,Jilin University |
Zhao X.,Jilin University
Chemical Research in Chinese Universities | Year: 2013
With Ti(SO4)2, SnCl4·5H2O and urea as raw materials, SnO2-TiO2 nanocomposites were synthesized via low temperature hydrothermal method at 80-100 °C in aqueous solutions. The morphologies of the products were altered systematically by varying the Ti/Sn molar ratio of the reactants, and rutile-phase particles were obtained with an average diameter of about 52.2 nm at a molar ratio of Ti/Sn=7.5. The surface composition of the composite was revealed by X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) to be solely TiO2 with a rutile structure. This new composite material exhibits a high ultraviolet absorption capacity, and its photocatalytic activity for phenol oxidation is much lower than that of the commercial titania nanoparticles(P25). © 2013 Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH.
Zhang M.,Tsinghua University |
Liu W.,Tsinghua University |
Nie X.,Tsinghua University |
Li C.,Tsinghua University |
And 3 more authors.
Microbes and Environments | Year: 2012
Microbial community structures in biofilms of a clearwell in a drinking water supply system in Beijing, China were examined by clone library, terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing of the amplified 16S rRNA gene. Six biofilm samples (designated R1-R6) collected from six locations (upper and lower sites of the inlet, middle and outlet) of the clearwell revealed similar bacterial patterns by T-RFLP analysis. With respect to the dominant groups, the phylotypes detected by clone library and T-RFLP generally matched each other. A total of 9,543 reads were obtained from samples located at the lower inlet and the lower outlet sites by pyrosequencing. The bacterial diversity of the two samples was compared at phylum and genus levels. Alphaproteobacteria dominated the communities in both samples and the genus of Sphingomonas constituted 75.1%-99.6% of this phylum. A high level of Sphingomonas sp. was first observed in the drinking water biofilms with 0.6-1.0 mg L-1 of chlorine residual. Disinfectant-resistant microorganisms deserve special attention in drinking water management. This study provides novel insights into the microbial populations in drinking water systems and highlights the important role of Sphingomonas species in biofilm formation.
Yuan R.,University of Science and Technology Beijing |
Zhou B.,University of Science and Technology Beijing |
Wu X.,Beijing Municipal Environmental Monitoring Center |
Gu J.,Water Quality Monitoring Center |
Zhang L.,Water Quality Monitoring Center
Research of Environmental Sciences | Year: 2015
With economic development, pollution of surface water has become more and more serious. In addition, the requirements for drinking water quality have become more stringent after the “Standards for Drinking Water Quality” (GB/T 5749-2006) were implemented. In order to remove organic pollutants, biological activated carbon was employed as an important process in drinking water treatment. The filtration rate, carbon media height, temperature and carbon agearethe key factors affecting the treatment effect of the carbon filter. With Danjiangkou Reservoir water used as raw water, coagulation, sedimentation and sand filtration were employed as the influent of the carbon filter, and the effects of new-carbon, 1-year-carbon, 3-year-carbon and 5-year-carbon (the carbon age in May 2011) taken from a waterworks in Beijing were investigated based on the permanganate index and UV254 removal efficiencies during the period between April 2011 and May 2013.The results showed that with the increase of filtration rate, the removal efficiency of organic matter decreased. When the filtration rate was 8 m/h, the removal efficiencies of permanganate index and UV254 reached 41.9% and 41.2%, respectively. With the deepening of the media depth of the carbon filter, the total UV254 removal efficiency increased, but the removal amount by each millimeter of carbon was reduced. In summer, with high temperature, and with the help of the 1-year-carbon in the carbon filter, the permanganate index and UV254 removal efficiencies were 44.2%-57.4% and 38.5%-53.1%, respectively, higher than those in winter (38.9%-51.1% and 31.7%-45.5%, respectively). At the beginning of the usage of the activated carbon, the organic matters were mainly removed through adsorption. Since the carbon was used longer, the biodegradation became the dominant effect, and the influence of the carbon age was smaller. Therefore, the life cycle of the biological activated carbon can be extended appropriately for cost saving. ©, 2015, Editorial Department of Molecular Catalysis. All right reserved.
Zhang M.-L.,Beijing Technology and Business University |
Zhang M.-L.,Tsinghua University |
Liu W.-J.,Tsinghua University |
Li C.-P.,Tsinghua University |
And 2 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2015
To evaluate the microbial safety during the source water switch in a drinking water treatment plant in Beijing, bacterial community compositions and potential pathogensin the raw water and finished water were analyzed by pyrosequencing. The bacterial diversity of finished water was significantly lower than raw water. Proteobacteria were observed as one of the most dominant populations both in raw water and finished water, ranging from 11.99% to 95.48%. Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria dominated in this group. However, the relative abundance varied in raw water and finished water. Cyanobacteria were found in raw water and finished water after water switch. Several potential pathogens were detected in the finished water and the majorbacteria were Acinetobacterand Delftia. The occurrence of pathogens was associated with increased health risk. PCoA results showed that bacterial community structure in raw water before switch was significantly different from that after water switch, but water switch had little effect on the bacterial composition of finished water. The water treatment plant operated stably during water switch. ©, 2015, Chinese Society for Environmental Sciences. All right reserved.