Although the management of microbes in drinking water is of paramount importance for public health, there remain challenges in comprehensively examining pathogenic bacteria in the water supply system at the species level. In this study, high-throughput sequencing of nearly full-length 16S rRNA genes was performed to investigate the changes of the water bacterial community in three large-scale drinking water treatment plants (DWTPs) and their corresponding distribution systems during winter and summer. Our findings revealed significant differences in the bacterial community structure between winter and summer water samples for each DWTP and its distribution management area (DMA).
View Article and Find Full Text PDFEnvironmental DNA (eDNA) has increasingly been used to detect rare species (e.g., newly introduced nonindigenous species) in both terrestrial and aquatic ecosystems, often with distinct advantages over traditional methods.
View Article and Find Full Text PDFResidual dissolved aluminum (Al) in drinking water is becoming a serious concern due to its high potential risks to human health. However, the mechanism by which residual dissolved Al forms is yet to be elucidated in detail. In this study, the effects of pre-oxidation by ozonation and chlorination on the properties of dissolved organic matter (DOM) and residual Al concentrations remaining in solution after coagulation were explored in a pilot-scale test.
View Article and Find Full Text PDFEffect of pre-chlorination and pre-ozonation on Microcystis aeruginosa (MA) and Coccomyxa subellipsoidea (CS) as disinfection by-products (DBPs) precursors was investigated after coagulation-filtration. Pre-chlorination considerably decreased the autofluorescence of algae cells but barely influenced cell granularity. In comparison, after pre-ozonation more algae cells were associated with decreased cell size; yet less reduction in the autofluorescence was observed.
View Article and Find Full Text PDFTo understand the processes of corrosion by-product release and the consequent "red water" problems caused by the variation of water chemical composition in drinking water distribution system, the effect of sulphate and dissolved oxygen (DO) concentration on total iron release in corroded old iron pipe sections historically transporting groundwater was investigated in laboratory using small-scale pipe section reactors. The release behaviors of some low-level metals, such as Mn, As, Cr, Cu, Zn and Ni, in the process of iron release were also monitored. The results showed that the total iron and Mn release increased significantly with the increase of sulphate concentration, and apparent red water occurred when sulphate concentration was above 400 mg x L(-1).
View Article and Find Full Text PDFMicrobial 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.
View Article and Find Full Text PDFThe corrosion scales on iron pipes could have great impact on the water quality in drinking water distribution systems (DWDS). Unstable and less protective corrosion scale is one of the main factors causing "discolored water" issues when quality of water entering into distribution system changed significantly. The morphological and physicochemical characteristics of corrosion scales formed under different source water histories in duration of about two decades were systematically investigated in this work.
View Article and Find Full Text PDFThree strains of Gram-negative bacteria capable of removing geosmin from drinking water were isolated from biologically active carbon and identified to be Chryseobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp.
View Article and Find Full Text PDFTwo granular activated carbon (GAC) samples with 1.5 a and 5 a age were collected, Bacterial genome DNA was extracted for the 16S rDNA gene amplification, and then a bacterial 16S rDNA gene clone library was constructed. After the phylogenetic analysis of 16S rDNA sequences, bacterial diversity and community structure of two activated carbon biofilm sample were studied.
View Article and Find Full Text PDFRed water phenomenon occurred in some communities of a city in China after water source switch in recent days. The origin of this red water problem and mechanism of iron release were investigated in the study. Water quality of local and new water sources was tested and tap water quality in suffered area had been monitored for 3 months since red water occurred.
View Article and Find Full Text PDFIdentification of compositions of the biofilm in a Beijing simulator water distribution system pipe networks by PCR and single strand conformation polymorphism (PCR-SSCP) technique and analysis of its heterotrophic bacterial by heterotrophic plate count (HPC) were performed. Results showed that when the water velocities were same, the count of heterotrophic bacterial on the zinficated steel wall was about five times of the PVC. On the other hand, when the pipe materials were zinficated steel, the count of heterotrophic bacterial in the deadwater pipe wall was about 1/5 of the 0.
View Article and Find Full Text PDFThe formation and distribution of HAAs in copper pipe during chlorination was investigated. To determine the material influence of copper pipe, parallel experiments were performed in glass pipe. Results showed that there was no obvious difference between the sum of haloacetic acids (HAAs) and trihalomethanes (THMs) produced in copper pipe compared to that produced in glass pipe over a 12h period.
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