Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.watres.2020.116674

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Publishing type：Research paper (scientific journal)  

© 2020 Elsevier Ltd Isolation of complex dissolved organic matter (DOM) from environmental water is a major challenge for unknown screening analysis by high-resolution mass spectrometry. In this study, DOM in process water during advanced drinking water treatment was fractionated sequentially by three solid-phase extraction (SPE) cartridges based on the polarity and charge of DOM molecules. By sequential SPE with unknown screening analysis, over 3000 DOM features were found in raw water, whereas around 2000 were obtained by a single SPE. The hydrophobic neutral (HPON) fraction contained CHO features with highest averaged molecular weight followed by hydrophobic acid (HPOA) and then hydrophilic acid (HPIA). The average degree of carbon double bond equivalents and carbon oxidation states indicated that the HPON fraction contained molecules that were more unsaturated and less oxidized than those of the HPOA and HPIA fractions. Ozone selectively decomposed (1) more unsaturated and less oxidized HPON features, (2) more unsaturated HPOA compounds, and (3) less oxidized HPIA molecules. Oxidation by-products were mostly HPON and HPIA compounds that were more oxidized than the decomposed molecules. During biological activated carbon (BAC) filtration, less oxidized HPON were preferentially removed, whereas HPOA were removed without selectivity. HPON and HPIA molecules with more oxidized character were found to be refractory to BAC treatment. HPON with more unsaturated and HPIA with more oxidized characters were decomposed by chlorine. Many types of HPIA decomposed during chlorination were the oxidation by-products of ozonation that were refractory to BAC treatment. Sequential SPE with unknown screening analysis provided previously unknown details of the molecular characteristics of DOM and its changes during advanced water treatment.

DOI： 10.1016/j.chemosphere.2020.128278

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Publishing type：Research paper (scientific journal)   Publisher：Japan Society for Environmental Chemistry  

DOI： 10.5985/emcr.20200006

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Language：Japanese   Publisher：Japan Society on Water Environment  

To verify a statistical model for predicting urban pollutant runoff developed in our previous research, newly obtained runoff data were compared with those predicted by the model. The proposed model previously was a regression model using parameters representing geological, rainfall, and hydrological characteristics. The targeted pollutants were COD, SS, TN, and TP, and their event mean concentrations (EMCs) for each rainfall were predicted. From the comparison, the model was found to predict the EMC to one order of magnitude. Moreover, the yearly mean EMC was evaluated from only the mean and standard deviation of all data for each index. The error ratio of the prediction of the mean of 50 rainfall events was within 50%. Furthermore, in order to consider the possible differences among different catchment areas, the EMC values for three catchment areas newly obtained were compared statistically with nationwide values obtained previously. Significant differences were found for one area out of the three which thus emphasizes the importance of the consideration of catchment area differences. Thereafter, the number of runoff samples in a specific watershed area required to detect the mean EMC difference from the nationwide database was derived statistically. This number was calculated to be 10 at most for detecting more than double or less than half of the database means. Lastly, a modified model that includes watershed area differences using a generalized linear mixed model was proposed.

DOI： 10.2965/jswe.44.1

CiNii Books

CiNii Research

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Other Link： http://id.ndl.go.jp/bib/031867545

Language：English   Publishing type：Research paper (scientific journal)  

Nitrification is a key function of biological activated carbon (BAC) filters for drinking water treatment. It is empirically known that the nitrification activity of BAC filters depends on water temperature, potentially resulting in the leakage of ammonium from BAC filters when the water temperature decreases. However, the ammonium removal capacity of BAC filters and factors governing the capacity remain unknown. This study employed a bench-scale column assay to determine the volumetric ammonium removal rate (VARR) of BAC collected from a full-scale drinking water treatment plant. VARR was determined at a fixed loading rate under different conditions. Seasonal variations of the VARR as well as impacts of the water matrix and water temperature on ammonium removal were quantitatively analyzed. While the VARR in an inorganic medium at 25 °C was maintained even during low water temperature periods and during breakpoint chlorination periods, the water matrix factor reduced the VARR in ozonated water at 25 °C by 33% on average. The VARR in ozonated water was dependent on water temperature, indicating that the microbial activity of BAC did not adapt to low water temperature. The Arrhenius equation was applied to reveal the relationship between VARR and water temperature. The actual ammonium removal performance of a full-scale BAC filter was predicted. VARR is useful for water engineers to reexamine the loading and filter depth of BAC filters.

DOI： 10.1021/acs.est.0c02502

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Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.watres.2020.116130

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.scitotenv.2020.143067

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.jhazmat.2020.124043

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Language：English   Publishing type：Research paper (scientific journal)  

Isotope dilution techniques (IDT) and sequential extraction procedures (SEPs) were compared to apprehend the differences between two techniques in determining metal exchangeability and vulnerability to pollute the urban groundwater. For this purpose, soil (n = 2), "soakaway" sediment deposited in the artificial infiltration facilities (AIF) (n = 4), and road dust (n = 2) were sampled from Tokyo metropolitan. Sorption coefficients of four metals (Cu, Zn, Cd and Pb) were assessed through isotopic exchangeability (E-value) and potential mobile pool i.e. addition of exchangeable, reducible and oxidizable fraction obtained by Community Bureau of Reference (BCR)-procedures. The E-value for the three samples were found smaller than the potential mobile pool but were higher than BCR-exchangeable fractions. The use of strong extractants are likely to play an active role in the disagreement between SEPs and IDT. IDT accounts for the isotopic exchangeability while BCR provides information of vulnerability of metals associated with different fractions that can leach under different environmental conditions. Sorption coefficients measured in soakaway sediment was found comparable to soil thus likely to retain metals. However, as variability in environmental conditions is likely to affect Kd, the soakaway sediment may become an active metal source in future rather than acting as the permanent sink. The study concludes that there is the possibility of errors while predicting metal vulnerability to groundwater with both techniques and thus a model compliance integrating the virtue of both techniques will be a way forward.

DOI： 10.1016/j.chemosphere.2020.126605

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Publishing type：Research paper (scientific journal)  

© 2020 Elsevier Ltd Isotope dilution techniques (IDT) and sequential extraction procedures (SEPs) were compared to apprehend the differences between two techniques in determining metal exchangeability and vulnerability to pollute the urban groundwater. For this purpose, soil (n = 2), “soakaway” sediment deposited in the artificial infiltration facilities (AIF) (n = 4), and road dust (n = 2) were sampled from Tokyo metropolitan. Sorption coefficients of four metals (Cu, Zn, Cd and Pb) were assessed through isotopic exchangeability (E-value) and potential mobile pool i.e. addition of exchangeable, reducible and oxidizable fraction obtained by Community Bureau of Reference (BCR)-procedures. The E-value for the three samples were found smaller than the potential mobile pool but were higher than BCR-exchangeable fractions. The use of strong extractants are likely to play an active role in the disagreement between SEPs and IDT. IDT accounts for the isotopic exchangeability while BCR provides information of vulnerability of metals associated with different fractions that can leach under different environmental conditions. Sorption coefficients measured in soakaway sediment was found comparable to soil thus likely to retain metals. However, as variability in environmental conditions is likely to affect Kd, the soakaway sediment may become an active metal source in future rather than acting as the permanent sink. The study concludes that there is the possibility of errors while predicting metal vulnerability to groundwater with both techniques and thus a model compliance integrating the virtue of both techniques will be a way forward.

DOI： 10.1016/j.chemosphere.2020.126605

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Language：English   Publishing type：Research paper (scientific journal)  

Recreational activities in coastal waters that are polluted by enteric viruses can result in gastroenteritis etc. In this study, the pollution profiles of enteric viruses were examined in the coastal area of Tokyo Bay, Japan, by collecting 57 water samples from three different depths (0.5 m, 3.0 m, and 5.0 m) during and after a series of heavy rainfall events. Vertically spatial and temporal changes in the concentrations of NoV genogroup I (GI) and genogroup II (GII), pepper mild mottle virus (PMMoV), and Aichi virus (AiV) were determined using quantitative reverse transcription-polymerase chain reaction, while those of the bacterial indicator, Escherichia coli, and F-specific RNA bacteriophages (FRNA phages) were monitored using culture methods. PMMoV was highly abundant (1.4 × 104-6.8 × 106 genome copies/L), whereas the concentrations of the other enteric viruses were relatively low (AiV, 1.3 × 102-2.9 × 104; GI, 2.9 × 10-5.6 × 103; GII, 2.5 × 10-1.2 × 104 genome copies/L). All of the viruses showed lower fluctuations in concentration than E. coli, which increased up to 460-fold after the rainfall event and then decreased over the subsequent two weeks. The maximum vertical difference in E. coli concentration was observed immediately after the rainfall. The E. coli reached the surface and then gradually spread down, whereas the virus concentrations exhibited few fluctuations due to the remaining effects of the previous combined sewer overflows. These findings indicate that viruses have a relatively long retention period over fecal indicator bacteria in this coastal area.

DOI： 10.1016/j.scitotenv.2020.138502

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Language：English  

Escherichia coli normally cannot grow in the environment. One environmental stress that prevents E. coli growth may be the competition for growth substrates with co-existing microorganisms. In this study, the growth substrates of E. coli were screened by high resolution mass spectrometry and compared with those of indigenous bacteria in river water. In an incubation experiment, E. coli multiplied in sterilized river water, but did not multiply when indigenous microorganisms were present in the water. By analysing dissolved organic matter in the river water before and after E. coli growth, 35 compounds were identified as putative growth substrates of E. coli. Among them, 33 compounds were also identified as putative growth substrates of indigenous bacteria. These results indicate that E. coli and indigenous bacteria compete for organic substrates in river water, which could suppress the growth of E. coli.

DOI： 10.1111/lam.13343

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.watres.2020.116130

PubMed

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© The Royal Society of Chemistry. Rapid urbanization induces organic pollution in closed water bodies and accelerates eutrophication. Dissolved organic matter (DOM), a major fraction of organic matter, causes various problems in water use. DOM sources in lakes are diverse. Moreover, DOM properties can be altered biologically and physicochemically during retention time. However, DOM in lakes consists of complex unknown substances. In the present study, high-resolution Orbitrap mass spectrometry (Orbitrap MS) was employed to determine the molecular-level composition of low-molecular-weight DOM in Lake Inba, the most polluted eutrophic lake in Japan. One-year monitoring demonstrated that the lake's DOM consisted of core components that were detected year-around and season-specific components. Although most DOM components extracted by solid phase extraction in the lake came from inflow rivers, lake-specific components were present, which could be associated with algal growth in the lake. Permanganate pretreatment was integrated with Orbitrap MS to screen for components contributing to dissolved chemical oxygen demand (DCODMn), an environmental parameter used in Japan to define the water quality of lakes and reservoirs. Results indicated that only minor and highly unsaturated components were responsible for DCODMn. With this approach, we were able to shed light on how the DOM composition in a eutrophic lake was shaped at molecular level, which cannot be achieved by conventional analysis.

DOI： 10.1039/d0ew00129e

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© 2020 IWA Publishing. All rights reserved. Dissolved organic matter (DOM) causes organic pollution in lakes, resulting in the occurrence of off-flavour etc. when lake water is used as a drinking water source. In this study, DOM in 11 major lakes in Japan was characterised by high-resolution Orbitrap mass spectrometry. Molecular formulas were assigned to 845-1,451 components per sample. Among them, 555 components were commonly found in all lakes. The DOM compositions of the 11 lakes were clustered into four groups. Correlation analysis could extract specific components whose relative intensities were associated with water quality indices such as specific ultraviolet absorbance, specific dissolved chemical oxygen demand (DCODMn), and specific trihalomethane formation potential (R = 0.80-0.93, p<0.05). Although further molecular structural analyses of DOM components are necessary, these results could be informative for exploring key candidates related to specific water quality issues. Pretreatment of samples with permanganate oxidation was applied to screen components which could contribute to DCODMn. DCODMncomponents accounted for only 7-30% of total peak intensities, indicating the limited performance of permanganate oxidation. Pre-treatment by permanganate coupled with Orbitrap MS revealed that components with higher molecular weight, higher oxygen-tocarbon ratios (O/C), and lower hydrogen-to-carbon ratios (H/C) could be responsible for DCODMn.

DOI： 10.2166/ws.2020.042

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Language：English   Publishing type：Research paper (scientific journal)  

Assays based on the polymerase chain reaction (PCR) are widely applied to quantify enteric viruses in aquatic environments to study their fates and potential infection risks. However, inhibitory substances enriched by virus concentration processes can result in inaccurate quantification. This study aimed to find a method for improving virus quantification by mitigating the effects of inhibitory environmental concentrates, using previous knowledge of the properties of the inhibitory substances. Performances of anion exchange resins, gel filtration, and a hydrophobic resin (DAX-8) were comparatively evaluated using poliovirus and its extracted RNA spiked into humic acid solutions. These solutions served as good representatives of the inhibitory environmental concentrates. A sequential treatment using DAX-8 resin and gel filtration produced the most favorable results, i.e., low virus losses that were stable and a reduced inhibitory effect. Furthermore, the sequential treatment was applied to another set of 15 environmental concentrates. Without the sequential treatment, serious underestimation (>4.0 log10 to 1.1 log10) of a molecular process control (murine norovirus) was measured for eight samples. With the treatment, the control was detected with <1.0 log10 underestimation for all samples. The treatment improved the quantification of seven types of indigenous viruses. In summary, the sequential treatment is effective in improving the viral quantification in various of environmental concentrates.

DOI： 10.1016/j.watres.2020.115652

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Publishing type：Research paper (scientific journal)  

© 2020 Japan Society on Water Environment. Polymeric materials are widely used in premise plumbing. To assess the potential of pipe materials to promote microbial regrowth in drinking water, we incubated drinking water in a new cross-linked polyethylene pipe (N-PEX), a new steel pipe lined with powdered polyethylene (N-SPE), and an old steel pipe lined with powdered polyethylene (O-SPE). As a reference, we also incubated drinking water in a carbon-free glass bottle (REF). Free chlorine rapidly depleted to below the quantification limit in the pipe incubations. While the original drinking water contained 0.4 mg C/L of dissolved organic carbon (DOC), the DOC concentration in N-PEX, N-SPE and O-SPE increased to 5.2, 3.1 and 1.7 mg C/L, respectively, after 8 days of incubation. The total cell count (TCC) in N-PEX, N-SPE, and O-SPE increased from <103 cells/mL to 6.0 × 105, 2.8 × 105, and 3.6 × 106 cells/mL after 8 days of incubation, respectively. On the other hand, the TCC in REF increased to 1.4 × 105 cells/mL after 14 days of incubation. Dominant bacterial groups were different under the different incubation conditions. These results indicated that organic matter migrating from pipe materials promote microbial regrowth and affect the microbial community composition in drinking water.

DOI： 10.2965/jwet.19-078

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© 2020 The Society for Applied Microbiology Aims: A continuous quench-flow (CQF) reactor was developed to collect samples at the reaction times of less than one second. The reactor is applied to determine ozone disinfection kinetics of poliovirus and to study whether EMA-qPCR can assess the viral infectivity after ozone disinfection. Methods: Ozone disinfection of poliovirus was conducted in the developed CQF, and the disinfection kinetics were tested in the range of 0·7–5·0 s at ozone concentration of 0·08 and 0·25 mg l−1. Inactivation, damage on viral genome and damage on capsid integrity were determined by plaque assay, quantitative reverse transcription polymerase chain reaction (RT-qPCR) and ethidium monoazide treatment coupled with RT-qPCR (EMA-qPCR), respectively. Results: By using CQF, 2·18 and 2·76 log10 reductions were observed at the reaction time of 0·7 s and ozone concentration of 0·08 and 0·25 mg l−1, respectively, followed by tailing. Ozone disinfection kinetics of poliovirus 1 were better fit by the efficiency factor Hom model than by the Chick-Watson model, or the modified Chick-Watson model. Kinetics observed were similar between RT-qPCR and EMA-qPCR assays at the reaction times of <2·0 s and ozone concentrations of 0·08 and 0·25 mg l−1. At reaction times > 5 s, viral concentration evaluated by EMA-qPCR was reduced in comparison to stable RT-qPCR results. Both assays still underestimated the virus inactivation. Conclusion: The simple developed reactor can be used to investigate viral ozone disinfection kinetics and to elucidate inactivation characteristics or mechanisms at very short exposure times. Significance and Impact of the Study: The developed CQF reactor is beneficial for better understanding of virus inactivation by ozone, and the reactor can be used to better elucidate disinfection kinetics and mechanisms for future research. This work constitutes an important contribution to the existing knowledge of the application and limitation of the EMA/PMA-qPCR to assess virus infectivity after ozone disinfection.

DOI： 10.1111/jam.14787

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Language：English   Publishing type：Research paper (scientific journal)  

Reverse osmosis (RO) membrane is widely used for household water treatment in areas with limited access to safe drinking water; however, some studies documented deterioration in the quality of RO permeate. Repeated pressurization from intermittent operation in households is suspected to have an adverse effect on RO. This study aimed to evaluate virus removal by RO used in actual households as well as the water quality of permeate, and to elucidate the main cause of RO deterioration. We conducted a survey in households in Hanoi, Vietnam, to collect 27 membranes along with their usage history, where virus removal was investigated in laboratory. Of the used RO membranes, 22% did not show the protective level, >3 log10 (99.9%) virus removal, recommended by World Health Organization. The differences in virus removal among Aichi virus, MS2 and φX-174 were <0.5 log10. All membranes with estimated pressurization times of <4000 showed >3 log10 virus removal, while 17% of membranes used for <3years, the manufacturers' warranty period, did not achieve the criterion. Therefore, virus removal performance may not be assured even if the users replace the membrane following the warranty period. Furthermore, more pressurized membranes exhibited significantly lower virus removal than less pressurized ones, suggesting a major role of repeated pressurization in the deterioration of RO. Coliforms were detected from 44% of the permeate of the point-of-use devices applying RO (RO-POU), raising concerns on the extrinsic contamination and regrowth of bacteria. Consequently, RO in households may deteriorate more rapidly than the manufactures' expectation due to repeated pressurization. RO in households should be replaced based on not only membrane age but also total pressurized times (i.e., 4000 times) to keep the protective level of virus removal. The deteriorated bacterial quality in RO permeate suggested the need for installing post-treatment, such as UV irradiation.

DOI： 10.1016/j.scitotenv.2019.133814

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

Reverse osmosis (RO) membrane is widely used for household water treatment in areas with limited access to safe drinking water; however, some studies documented deterioration in the quality of RO permeate. Repeated pressurization from intermittent operation in households is suspected to have an adverse effect on RO. This study aimed to evaluate virus removal by RO used in actual households as well as the water quality of permeate, and to elucidate the main cause of RO deterioration. We conducted a survey in households in Hanoi, Vietnam, to collect 27 membranes along with their usage history, where virus removal was investigated in laboratory. Of the used RO membranes, 22% did not show the protective level, >3 log(10) (99.9%) virus removal, recommended by World Health Organization. The differences in virus removal among Aichi virus, MS2 and phi X-174 were <0.5 log(10). All membranes with estimated pressurization times of <4000 showed >3 logic virus removal, while 17% of membranes used for <3 years, the manufacturers' warranty period, did not achieve the criterion. Therefore, virus removal performance may not be assured even if the users replace the membrane following the warranty period. Furthermore, more pressurized membranes exhibited significantly lower virus removal than less pressurized ones, suggesting a major role of repeated pressurization in the deterioration of RO. Coliforms were detected from 44% of the permeate of the point-of-use devices applying RO (RO-POD), raising concerns on the extrinsic contamination and regrowth of bacteria. Consequently, RO in households may deteriorate more rapidly than the manufactures' expectation due to repeated pressurization. RO in households should be replaced based on not only membrane age but also total pressurized times (i.e., 4000 times) to keep the protective level of virus removal. The deteriorated bacterial quality in RO permeate suggested the need for installing post-treatment, such as UV irradiation. (C) 2019 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.scitotenv.2019.133814

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© 2019 Elsevier B.V. Multi-drug resistant microbes, pathogenic viruses, metals, and pharmaceuticals and personal care products (PPCPs) in water has become the crux of urban sustainability issues. However, vulnerability due to pollutant concurrences, source apportionment, and identification of better faecal indicators needs to be better understood. The present study focuses on the vulnerability of urban Guwahati, the largest city in Northeastern India, through analyzing the concurrence of PPCPs, enteric viruses, antibiotic resistant bacteria, metal, and faecal contamination in water. The study strives to identify a relevant marker of anthropogenic pollution for the Indian scenario. Samples from the Brahmaputra River (n = 4), tributary Bharalu River (an unlined urban drain; n = 3), and Ramsar recognized Lake (Dipor Bil; n = 1) indicate caffeine > acetaminophen > theophylline > carbamazepine > crotamiton for PPCPs and pepper mild mottle virus (PMMoV) > aichi > hepatitis A > norovirus GII > norovirus GI for enteric viruses. PMMoV was the better indicator of faecal pollution due to its prevalence, specificity and ease of detection. Antibiotic resistance was neither correlated with the prevalence of PPCPs nor E. coli. As, Co and Mn appear to be inducing antibiotic resistance in E. coli. While the risk quotient of the urban drain (Bharalu River) indicates one order higher magnitude than reported for other Indian rivers, the Lake exhibited the least pollution and better resilience. The concurrence of pollutants and multi-drug resistant E. coli, owing to the complete absence of wastewater treatment, puts the city in a highly vulnerable state. Pollution is being regulated only by the dilution capability of the Brahmaputra River, which needs to be further researched for seasonal variation.

DOI： 10.1016/j.scitotenv.2019.133640

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

It is important to evaluate the removal of enteric viruses by drinking water treatment processes so that viral infection risk can be assessed and managed. However, evaluating the removal of enteric viruses by full-scale treatment processes can be challenging due to the low numbers of viruses and the presence of substances in the water samples that inhibit detection. In this study, we evaluated the removal of pepper mild mottle virus (PMMoV) by microfiltration (MF) and slow sand filtration (SSF) at two full-scale drinking water treatment plants in Japan, quantifying virus concentrations with real-time polymerase chain reaction (qPCR). The removal of PMMoV by MF ranged from 0.0 to >0.9 log(10), although concentrations were below the detection limit for half of the treated water samples. SSF removed PMMoV by up to 2.8 log(10); however, the removal efficiency decreased to 0.0-1.0 log(10 )under cold water temperatures. Process control showed that nucleic acid extraction and qPCR efficiency were inhibited in nearly 40% of water samples. Dilution, DAX-8, and ferrihydrite treatments for purification were effective in mitigating these inhibitory effects.

DOI： 10.1038/s41545-019-0042-1

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Publishing type：Part of collection (book)   Publisher：Springer Singapore  

DOI： 10.1007/978-981-15-0291-0_182

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DOI： 10.1016/j.watres.2019.05.002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Reverse osmosis (RO) membranes are commoditized and available for household water treatment (HWT) in areas where access to safe water is limited. The RO membranes for HWT (residential RO) are typically operated intermittently without a cleaning process. This suggests that a unique mechanism of membrane deterioration, membrane oxidation, one of the main causes of RO membrane deterioration in industrial settings (desalination and wastewater reclamation), is not involved. Furthermore, the intermittent operation provides repeated shear stress on the membrane surface. This study aimed to evaluate the impact of repeated pressurization on virus (bacteriophage MS2 and phi X-174) removal by residential RO and to determine the location of integrity loss. We repeatedly pressurized and de-pressurized spiral-wound residential RO membranes for up to 10 000 cycles, while periodically evaluating virus removal. E. coli removal was also determined after 10 000 cycles. Moreover, these membranes were examined for virus and E. coli removal in a flat-sheet configuration. For the first 3000-4000 cycles, phi X-174 removal was maintained at approximately 4 log(10) (99.99%), and then dramatically decreased. After 10 000 cycles, even E. coli leaked from the membrane. The deterioration of virus removal in a flat-sheet configuration indicates integrity loss at the membrane surface. Therefore, repeated pressurization deteriorated the virus removal performance of residential RO. The number of times that the RO membrane can be pressurized should be included as a criterion to determine the frequency of membrane replacement in residential RO.

DOI： 10.1039/c8ew00944a

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DOI： 10.1007/s13201-019-0932-x

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DOI： 10.1007/s12560-019-09368-2

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DOI： 10.1039/c8ew00541a

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DOI： 10.1016/j.jviromet.2018.10.018

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Publishing type：Research paper (scientific journal)  

© 2019 Japan Society on Water Environment. In 2016, only 56.7% of the lakes and reservoirs in Japan complied with the standard of chemical oxygen demand determined by permanganate (COD Mn ). The dissolved organic matter (DOM) contributing to COD Mn in lakes is heterogenous in nature; hence, DOM compositions in different lake waters are not well known. In this study, molecular components contributing to dissolved COD Mn (DCOD Mn ) in lake water were identified via high-resolution Orbitrap mass spectrometry (Orbitrap MS). Water samples were collected from Lake Inba in September 2016. The filtered samples were oxidized by KMnO 4 according to the JIS method K0102 for different durations (ranging between 0-120 min). The DOM extracted via solid phase extraction was analyzed using Orbitrap MS, and molecular formulas were assigned. In all, 1,115 components were observed before oxidation. During time-course oxidation, components with higher unsaturation were selectively oxidized, suggesting that they contributed to the DCOD Mn in lake water. DCOD Mn components were screened for DOM in Lake Inba, and other DOM references were isolated from the Suwannee River and Lake Biwa. Only 14%-32% of the total components were regarded as DCOD Mn components, indicating the limited coverage of COD Mn . The compositions of DCOD Mn components were highly diverse, depending on the sources.

DOI： 10.2965/jwet.18-043

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DOI： 10.3390/w10121830

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DOI： 10.1016/j.watres.2017.12.068

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DOI： 10.1021/acs.est.7b04765

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society on Water Environment  

To assess the potential risk of viral infection through drinking water, a rapid and effective method to quantify pathogenic viruses is necessary. Ethidium monoazide (EMA) combined with reverse transcription qPCR (EMA-RT-qPCR) is a currently widely accepted method to assess the integrity of viruses. However, this technique can be hampered by humic acids which are co-concentrated during virus concentration processes (VCPs). Co-concentration of four commercially available humic acids (Ald, Wa, Na, and IH) during VCPs and their impacts on the subsequent EMA-RT-qPCR over spiked intact Aichi virus 1 and its naked RNA were studied. The recoveries of Ald, Wa, Na, and IH during VCPs were less than 8.9%, 5.4%, 7.2%, and 0.7%, respectively, indicating that IH was much less concentrated than other humic acids. In the concentrates, Ald, Wa, and Na caused severe inhibition of EMA-RT-qPCR, whereas only a slight inhibitory effect on IH was observed. Tests of the influence of actual drinking water concentrates on EMA-RT-qPCR indicated the absence of severe inhibition. Therefore, EMA-RT-qPCR has a high potential for monitoring enteric viruses in drinking water.

DOI： 10.2965/jwet.17-044

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society on Water Environment  

Water sampling was conducted in the coastal area of Tokyo following two rainfall events in October and November 2016. The coastal area receives, through urban rivers, a considerable amount of combined sewer overflow (CSO) pollutants from overflow chambers and pumping stations. Five pharmaceutical and personal care products (PPCPs) including acetaminophen, theophylline, crotamiton, carbamazepine, and caffeine were analyzed and used as chemical sewage markers. In addition, two types of bacteriophage were counted as markers for viral contamination as well as the fecal bacterial indicators Escherichia coli and total coliform. High contamination by PPCPs and microbial fecal indicators was observed after the rainfall events. Five key markers were selected among nine target markers using correlation analysis and were used to express the spatial distribution and temporal change in CSO pollutants. Escherichia coli showed relatively fast die-off behavior and decreased sharply from one day after the rainfall events, while bacteriophages persisted for several days after the events. Somatic coliphage showed more persistent behavior than F-specific bacteriophage. Labile markers such as caffeine also showed high rates of disappearance. In addition, monitoring results suggested that combined analyses of PPCPs and microbial fecal indicators can provide a more informed discussion on the distribution and diffusion of sewage contaminants in coastal waters following rainfall events.

DOI： 10.2965/jwet.17-052

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Quantitative detection of pathogenic viruses in the environmental water is essential for the assessment of water safety. It is known that some of natural organic substances interfere with virus detection processes, i.e., nucleic acid extraction and reverse transcription-PCR. Such substances are carried over into a sample after virus concentration. In this study, inhibitory substances in coastal water samples were characterized in view of their effects on efficiency of virus detection and property as organic matters. Among 81 samples tested, 77 (95%) showed low recoveries (&lt;10%) of spiked murine norovirus. These recovery rates were correlated with the levels of organic matter present in virus concentrates as measured by ultraviolet absorbance at 254 nm (r = -0.70 - -0.71, p &lt; 0.01). High-performance gel chromatography and fluorescence excitation-emission matrix spectroscopy revealed that organic fractions in the 10-100 kDa size range, which were not dominant in the original samples, and those possessing humic acid-like fluorescence properties were dominant in virus concentrates. The inhibitory effect was more pronounced during summer. Substances originating from seawater seemed to cause a more pronounced effect than those originating from wastewater. Our data highlight the previously unknown characteristics of natural inhibitory substances and are helpful in establishing an effective sample purification technique.

DOI： 10.1021/acs.est.7b00306

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Language：Japanese  

DOI： 10.2208/jscejhe.73.I_1381

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Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

In recent years, local heavy rainfall and associated flood disasters are becoming serious issue. It is reported that in the Tokyo metropolitan area, more than 70 percent of flood damage was attributed to the local heavy rainfall. While the progress of urban drainage network construction is still in progress and the budget for public work is under decline, application of numerical model for inundation prediction is becoming important. In this study, we analyze urban inundation by applying seamlessly integrated river-, urban-, and coastal hydraulics model in the Tsurumi river basin where integrated flood management has been taken place, with giving XRAIN, High Resolution Precipitation Nowcasting, and Short-term Precipitation Forecasting as forcings. The results showed improved advantage compared to MSM-GPV and effective combination of rainfall data shall contribute to realize the inundation prediction on a real-time basis.

DOI： 10.11520/jshwr.30.0_106

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society on Water Environment  

Lake Inba, which serves as a drinking water source in Chiba Prefecture, Japan, has not complied with the environmental standard for COD (3 mg/L) since the 1970s. The high level of dissolved organic matter (DOM) caused by eutrophication in the lake has risen the concern of water treatment. To understand the compositions and sources of DOM in Lake Inba, this study compared molecular compositions of low molecular weight DOM (LMW-DOM, &lt
1 kDa) in the lake and a major river flowing to the lake. Water samples were collected from Lake Inba and Kashima River in June 2015. After solidphase extraction, LMW-DOM was analyzed by Orbitrap mass spectrometry coupled with electrospray ionization. Based on the accurate mass data, 1,263 and 1,393 molecular formulae were assigned for the lake and river samples, respectively. Among them, 1,193 formulae were shared between the lake and the river, indicating that Kashima River was the representative source of LMW-DOM in the lake at the sampling occasion. Elemental composition of molecular formula demonstrated that 61% of the shared formulae were composed of carbon, hydrogen and oxygen. Hydrogen to carbon ratio and oxygen to carbon ratio of these common molecules were similar to the fingerprints of lignin and tannin.

DOI： 10.2965/jwet.16-054

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

The nitrogen load was determined in road runoff during rainfall events. Moreover, nitrate isotopes analysis was conducted to determine the contribution of nitrates from atmospheric deposition and leaching from road dust. The concentrations of NO3-N in road runoff were higher than those in atmospheric deposits for each rainfall event, except one event with a long antecedent dry weather period. The O-18-NO3 in road runoff was lower than in atmospheric deposits and higher than in leachate from road dust; however, no difference in N-15-NO3 was observed. By using O-18-NO3 as an indicator for evaluating NO3-N sources in road runoff, contribution ratios of NO3-N from road dust were estimated to be 14-22%, 23-25%, and 22-34% for Event 1 to Event 3, respectively. These results indicated that the NO3-N from the atmosphere accounts for more than half of the NO3-N in road runoff.

DOI： 10.1080/1573062X.2016.1148176

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Publishing type：Research paper (scientific journal)  

DOI： 10.2208/kaigan.73.I_499

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DOI： 10.2323/jgam.2017.03.003

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Language：Japanese  

雨天時における市街地流出を調査している報告書, 論文等の文献を収集し (1968〜2011年) , 一降雨を単位とした市街地の汚濁負荷 (BOD, COD, SS, TN, TP) の負荷流出データベース (DB) をまとめ, 一降雨の流量加重平均濃度 (EMC) の分布を明らかにした。続いて降雨条件, 地理的状況がEMCに及ぼす影響を回帰式で予測し, 日本全国の4地点での降雨条件を与えた際の年間流出負荷の予測値とその変動係数を導出した。その予測に基づき, 信頼性のある流出負荷量を算出するためにどの程度の降雨の採水頻度が必要になるのかをシミュレーションにより検討した。95％ 信頼区間を2倍以内程度の誤差とする場合, 水質項目によっては年間の全降雨イベントのうち半分程度を採水する必要があることを明らかにした。

DOI： 10.2965/jswe.40.115

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.2208/jscejer.72.III_361

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DOI： 10.2166/ws.2016.056

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DOI： 10.1016/j.watres.2016.05.012

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DOI： 10.1016/j.watres.2016.05.047

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IWA PUBLISHING  

Ozonation followed by a biological activated carbon (BAC) filter is a common process of advanced water purification. Ozone can generate formaldehyde (FA) as a harmful by-product, while the subsequent BAC filter is efficient at removing FA. FA adsorption is limited on activated carbon because of its hydrophilic property and low molecular weight. Thus, biological degradation by biofilms associated with the BAC is regarded as the primary treatment mechanism for FA. However, little is known about the microorganisms involved in the removal of FA. To identify specific microorganisms assimilating FA in a BAC filter, this study applied DNA stable isotope probing (DNA-SIP) combined with next-generation sequencing (NGS) technology. DNA-SIP with NGS clearly revealed that facultative methylotrophs affiliated within the specific taxonomic groups, such as Hyphomicrobium and Methylibium, were suspected to be the key players in FA removal.

DOI： 10.2166/ws.2016.039

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DOI： 10.1007/s00253-015-6969-3

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DOI： 10.2323/jgam.2016.04.001

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Language：English   Publisher：Japan Society on Water Environment  

Bacterial regrowth in reclaimed water, specifically observed when residual chlorine concentration declines along the distribution system, causes undesirable changes in water quality and hampers its acceptability. To study the impact of chlorination on regrowth and bacterial community structure, unchlorinated tertiary treated reclaimed water was collected and dosed with chlorine such that the initial doses were 1, 3, 5 mg-Cl₂/L before being stored at ambient temperature under dark condition. Chlorine measurement, cell counts and bacterial community profiling were carried out at regular intervals for 21 days. Addition of chlorine caused rapid decline in intact cell concentration and no regrowth was observed until free chlorine decayed below detection limit (0.03 mg-Cl₂/L). Upon regrowth, intact cell concentrations reached the initial level except in the case of 5 mg-Cl₂/L where the intact cell concentration was lower by 1-log₁₀. The dominant species that regrew under each condition were distinct, based on their capacity to withstand chlorine. The most chlorine-tolerant groups belonged to the order Sphingomonadales and Rhizobiales, which have been previously reported to initiate biofilms. This study demonstrates that chlorination selects specific bacterial groups which have the potential to regrow in the distribution network.

DOI： 10.2965/jwet.15-063

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;Urbanized coastal low-lying area has vulnerability against flood and inundation, which are caused by multiple flood causing factors occurring in coast, river and urbanized areas. Several cases of inundation were examined, in which designed water levels for warning were exceeded. Submodels were seamlessly integrated to simulate inundation caused by tsunami, storm surge, as well as river flood and urban inundation. In the same time, the model evaluated the performance of structural countermeasures such as sewage network, or retardation basin, when considering disaster management plan in coastal low-lying areas. We applied the seamlessly integrated model to the highly urbanized Tsurumi River basin and investigated inundation characteristics by considering multiple flood causing factors.

DOI： 10.2208/kaigan.72.I_517

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS INC  

The aims of this study were to examine the removal of bacteria and viruses by household point-of-use (POU) treatments and to apply a previously developed large-volume virus concentration method (approximate to 20L). First, the removal of microbes by household POU treatment was investigated in the laboratory. Second, the prevalence of viruses in drinking water sources for households and the removal efficiency of microbes by POU treatments in two suburban communities in Hanoi, Vietnam, were investigated. Indigenous pepper mild mottle virus (PMMoV) was used as the main target together with adenovirus, Aichi virus, enterovirus, F-specific bacteriophage genogroup 1, and Escherichia coli to investigate the removal efficiency of household treatments. The results from laboratory and field survey were compared. From the laboratory study, ceramic membranes were not effective for removing viruses and bacteria from water; pathogen reduction was less than 1.5log(10). By contrast, reverse osmosis (RO) devices reduced microbes by 3 to &gt; 5log(10). In a field study, PMMoV was found to be the most prevalent waterborne virus. Household sand filtration was ineffective for removing E. coli, total coliforms and PMMoV; the reduction was less than 1 order of magnitude. Boiling the water and then filtering it with a ceramic membrane reduced E. coli by 3 orders of magnitude, but this was not effective for removing PMMoV. RO filtration was one of the promising methods for removing E. coli, total coliforms and PMMoV to below their detection limits in most of the samples studied. The removal of E. coli, total coliforms and PMMoV was &gt;2.3, &gt;4 and &gt;3log(10), respectively. The laboratory results of virus removal efficiency by POU devices agreed with the field study. Due to the prevalence and characteristics of PMMoV, it is a strong candidate for an indigenous indicator to investigate the viral removal efficiency of household POU treatments.

DOI： 10.1080/10934529.2016.1199650

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IWA PUBLISHING  

River water samples were taken from 32 locations around the basin of Chaophraya River and its four major tributaries in Thailand to investigate resistance ratios of Escherichia coli isolates to eight antibiotic agents of amoxicillin, sulfamethoxazole/trimethoprim, tetracycline, doxytetracycline, ciprofloxacin, levofloxacin, norfloxacin and ofloxacin. Principal component analysis was performed to characterize resistance patterns of the samples. Relevancy of the obtained principal components with urban land use and fecal contamination of the river were examined. The ratio of antibiotic-resistant bacteria is likely to increase when urban land use near the sampling site exceeds a certain ratio. The resistance ratio to fluoroquinolones tends to be high in a highly populated area. Meanwhile, no significant contribution of fecal contamination was found to increase the resistance ratio. These results suggest that an antibiotic-resistance ratio is dependent on conditions of local urbanization rather than the upstream conditions, and that the major sources of antibiotic-resistant bacteria in the Chaophraya River basin are possibly point sources located in the urban area which contains a high ratio of resistant bacteria.

DOI： 10.2166/wst.2015.502

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The potential use of rainwater harvesting in conjunction with miscellaneous water supplies and a rooftop garden with rainwater harvesting facility for temperature reduction have been evaluated in this study for Hong Kong. Various water applications such as toilet flushing and areal climate controls have been systematically considered depending on the availability of seawater toilet flushing using the Geographic Information System (GIS). For water supplies, the district Area Precipitation per Demand Ratio (APDR) has been calculated to quantify the rainwater utilization potential of each administrative district in Hong Kong. Districts with freshwater toilet flushing prove to have higher potential for rainwater harvest and utilization compared to the areas with seawater toilet flushing. Furthermore, the effectiveness of using rainwater harvesting for miscellaneous water supplies in Hong Kong and Tokyo has been analyzed and compared; this revives serious consideration of diurnal and seasonal patterns of rainfall in applying such technology. In terms of the cooling effect, the implementation of a rooftop rainwater harvesting garden has been evaluated using the ENVI-met model. Our results show that a temperature drop of 1.3 degrees C has been observed due to the rainwater layer in the rain garden. This study provides valuable insight into the applicability of the rainwater harvesting for sustainable water management practice in a highly urbanized city. (c) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.watres.2015.07.040

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Language：English  

The current study involves characterization of organic compounds, heavy metals, and ammonia as potential toxicants in one arterial road (St. 3) and two highway (St. 7 and 8) urban road dust (URD) collected in Tokyo, Japan. URD toxicity was evaluated by Toxicity Identification Evaluation using the ostracod Heterocypris incongruens direct contact test. URDs were treated with resins (10% XAD-4, 20% SIR-300 and 20% SIR-600) to determine the reduction in mortality after treatment. The mortality of ostracods exposed to St. 3 URD (baseline 80%) was significantly (p&lt;0.05) reduced to 0% and 47% after XAD-4 and SIR-300 treatment respectively. This reduction led us to suspect hydrophobic organic compounds and heavy metals as potential toxicants. Subsequent elution of the recovered XAD-4 with polar (methanol, acetone) and non-polar (dichloromethane) solvents confirmed the dominance of relatively polar hydrophobic organic toxicants. The dissolved concentration of Cu and Zn after SIR-300 treatment exceeded the 50% lethal concentration (LC50) for ostracods, which led us to suspect Cu and Zn as other probable toxicants. The concentration of Zn in a SIR-300 acidic elutriate, recovered after the termination of toxicity test, confirmed Zn as one of the toxicants in St. 3. The baseline mortality (100%) of St. 7 was significantly reduced (23%) by SIR-300 treatment. This indicated the presence of heavy metals as the probable toxicant. However, the concentration of dissolved heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in the overlying water was below previously reported LC50 values for each metal in St. 7. Recovery of Zn concentrations exceeding the LC50 in the St. 7 SIR-300 elutriate led us to suspect a dietary exposure route of Zn to the ostracod during the direct contact test. The overall results indicate that the toxicant types can vary widely depending on the road sampled.

DOI： 10.1016/j.scitotenv.2015.05.090

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Natural oestrogens, which are degraded but not completely removed in wastewater treatment plants, are suspected of causing the endocrine disruption of aquatic organisms in the receiving water body. While several bacterial isolates were reported to be oestrogen-degrading bacteria, our previous study implied that only the unidentified rod-shaped Betaproteobacteria in chains were responsible for estrone (E1) degradation by activated sludge especially at the sub-milligram per litre level. The Betaproteobacteria were suspected to be related to genera Sphaerotilus and Leptothrix according to morphological observations. Probe Spha823 was newly developed to target 16S rRNA gene clones obtained from activated sludge and closely related to the above genera. [H-3]E1-incubated sludge samples showed that most of the H-3-labelled cells hybridized with probe Spha823 by microautoradiography (MAR) fluorescent in situ hybridization. Spha823-defined cells were present in all three activated sludge samples tested, where they accounted for up to 3% of the total microbial biomass. Spha823-defined cells comprised 595-801% of the total MAR-positive cells, which suggested that the Sphaerotilus-Leptothrix-related bacteria were the most abundant micro-organisms involved in E1 degradation (at 200gl(-1)) in the activated sludge samples.
Significance and Impact of the StudyEstrone (E1) is one of the natural estrogens, which can be degraded but is not always completely removed in wastewater treatment plants. E1 is suspected of causing the endocrine disruption of aquatic organisms in the receiving water body. We identified dominant E1-incorporating bacteria, which should include E1-degrading bacteria, in activated sludge treating domestic wastewater. Sphaerotilus-Leptothrix-related bacteria, which had never been reported in the previous attempts based on culture-dependent approach, occupied 60-80% of the E1-incorporating bacteria. This study demonstrates the identification of functionally active bacteria to degrade micro-pollutants at sub-milligram per litre level.

DOI： 10.1111/lam.12407

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Language：English  

This study investigated and characterised organic matter present in sediment particles deposited in infiltration facilities using an excitation-emission matrix method combined with parallel factor analysis (EEM-PARAFAC). The organic fluorophore identified was correlated with sediment bound metals. The PARAFAC analysis identified three major components. The fluorophore in each of the three components appeared in different locations with different spectral shapes. The maximum fluorescence intensity (F max) observed for each fluorescent component was correlated with seven heavy metals (Cr, Mn, Co, Ni, Cu, Zn and Pb). F max of component 1 displayed a negative relationship with all the metals (correlation coefficient = ?0.28 to ?0.72), and F max of component 3 showed a positive relationship (0.20 to 0.62), and among them, Cu, Ni and Zn had higher correlation. Our results demonstrate that a PARAFAC approach can help to further elucidate organic matter species, thereby allowing a better understanding of the mobility of elemental species in the deposited sediment.

DOI： 10.1007/s11270-015-2426-2

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Language：English  

Road run-off water quality can be significantly impacted by many pollutants deposited on road surfaces through vehicular activities. Any control strategy for the improvement of water quality relating to organic and inorganic pollutants should be based on a detailed knowledge of pollutant built-up processes and the relationship of pollutants to one another. Total volatile suspended solids (VSS), polycyclic aromatic hydrocarbons (PAHs) and heavy metals were estimated in total suspended solids (TSS) collected in two catchments. This study found a good relationship between total VSS and TSS and between TSS and PAHs. This relationship information can be utilized for the development of effective Best Management Practices for TSS control. However, the relationship between TSS and heavy metals was identified as being strong in only some cases.

DOI： 10.1080/19443994.2014.955827

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DOI： 10.1128/AEM.00563-15

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Language：English  

DOI： 10.1128/AEM.03082-14

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

The damage to a viral capsid after low-pressure (LP) and medium-pressure (MP) UV irradiation was assessed, using the quantitative or quantitative reverse transcription PCR coupled with ethidium monoazide treatment (EMA-PCR). After UV irradiation, adenovirus 5 (Ad5) and poliovirus 1 (PV1) were subjected to a plaque assay, PCR, and EMA-PCR to investigate the effect of UV irradiation on viral infectivity, genome damage, and capsid damage, respectively. The effectiveness of UV wavelengths in a viral genome and capsid damage of both PV1 and Ad5 was also further investigated using a band-pass filter. It was found that an MPUV lamp was more effective than an LPUV lamp in inactivating Ad5, whereas there was no difference in the case of PV1. The results of viral reduction determined by PCR and EMA-PCR indicated that MP UV irradiation damaged Ad5 capsid. The damage to PV1 and Ad5 capsid was also not observed after LP UV irradiation. The investigation of effects of UV wavelengths suggested that UV wavelengths at 230-245 nm have greater effects on adenovirus capsid in addition to viral genome than UV wavelengths beyond 245 nm.

DOI： 10.1007/s12560-014-9162-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE SOC MICROBIAL ECOLOGY, DEPT BIORESOURCE SCIENCE  

To identify the microorganisms involved in benzene degradation, DNA-stable isotope probing (SIP) with C-13-benzene was applied to a methanogenic benzene-degrading enrichment culture. Pyrosequencing of ribosomal RNA (rRNA) gene sequences revealed that the community structure was highly complex in spite of a 3-year incubation only with benzene. The culture degraded 98% of approximately 1 mM C-13-benzene and mineralized 72% of that within 63 d. The terminal restriction fragment length polymorphism (T-RFLP) profiles of the buoyant density fractions revealed the incorporation of C-13 into two phylotypes after 64 d. These two phylotypes were determined to be Desulfobacterales- and Coriobacteriaceae-related bacteria by cloning and sequencing of the 16S rRNA gene in the C-13-labeled DNA abundant fraction. Comparative pyrosequencing analysis of the buoyant density fractions of C-12- and C-13-labeled samples indicated the incorporation of C-13 into three bacterial and one archaeal OTUs related to Desulfobacterales, Coriobacteriales, Rhodocyclaceae, and Methanosarcinales. The first two OTUs included the bacteria detected by T-RFLP-cloning-sequencing analysis. Furthermore, time-resolved SIP analysis confirmed that the activity of all these microbes appeared at the earliest stage of degradation. In this methanogenic culture, Desulfobacterales- and Coriobacteriaceae-related bacteria were most likely to be the major benzene degraders.

DOI： 10.1264/jsme2.ME13104

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Rainfall events can introduce large amount of microbial contaminants including human enteric viruses into surface water by intermittent discharges from combined sewer overflows (CSOs). The present study aimed to investigate the effect of rainfall events on viral loads in surface waters impacted by CSO and the reliability of molecular methods for detection of enteric viruses. The reliability of virus detection in the samples was assessed by using process controls for virus concentration, nucleic acid extraction and reverse transcription (RT)-quantitative PCR (qPCR) steps, which allowed accurate estimation of virus detection efficiencies. Recovery efficiencies of poliovirus in river water samples collected during rainfall events (&lt;10%) were lower than those during dry weather conditions (&gt;10%). The log(10)-transformed virus concentration efficiency was negatively correlated with suspended solid concentration (r(2) = 0.86) that increased significantly during rainfall events. Efficiencies of DNA extraction and qPCR steps determined with adenovirus type 5 and a primer sharing control, respectively, were lower in dry weather. However, no clear relationship was observed between organic water quality parameters and efficiencies of these two steps. Observed concentrations of indigenous enteric adenoviruses, GII-noroviruses, enteroviruses, and Aichi viruses increased during rainfall events even though the virus concentration efficiency was presumed to be lower than in dry weather. The present study highlights the importance of using appropriate process controls to evaluate accurately the concentration of water borne enteric viruses in natural waters impacted by wastewater discharge, stormwater, and CSOs. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.scitotenv.2013.08.093

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Urban road dusts (URDs, n =10) were collected from arterial, residential, parking area in highway and highway roads in and around Tokyo, Japan, to characterize toxicity of size-fractions by the ostracod Heterocypris incongruens direct contact test. The URDs were collected with vacuum cleaner and highway sweeping vehicles, dried and size-fractionated before conducting toxicity test. The LC20 and LC50 of URDs varied (v/v) from 1.6 to 49%, and 3.8 to 67% respectively. Cluster analysis of URDs based on the concentration of heavy metal and PAHs standardized with the organic matter content was able to differentiate URDs into two groups, one group of higher toxicity and the other group of medium and lower toxicity. Mortality of ostracod decreased for some of the URDs when holding time of URD-water mixture was changed from 1 h to 24 h prior to the toxicity test. Fraction of fine particles was not always more toxic than the other fractions of coarse and medium particles. Site specific differences in toxicity of size-fractionated URDs indicated the complexity in defining URD toxicity as there could be co-existence of various non-targeted toxicants. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jhazmat.2013.10.058

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IWA PUBLISHING  

In the Citadel area of Hue City, drainage systems that include canals and ponds are considerable sources of fecal contaminants to inundated water during the rainy season because canals and ponds receive untreated wastewater. It is important to investigate the characteristics of hydraulics and water pollution in canals and ponds. At the canals and ponds, water sampling was conducted during dry and wet weather periods in order to evaluate fecal contamination and to investigate changes in water pollution caused by runoff inflow. Inundated water was also collected from streets during heavy rainfall. At the canals and ponds, concentrations of Escherichia coli and total coliform exceeded the Vietnamese regulation values for surface water in 23 and 24 out of 27 samples (85 and 89%), respectively. The water samples were categorized based on the characteristics of water pollution using cluster analysis. In the rainy season, continuous monitoring was conducted at the canals and ponds using water depth and electrical conductivity (EC) sensors to investigate the dynamic relationship between water level and water pollution. It is suggested that in the canals, high EC meant water stagnation and low EC signified river water inflow. Therefore, EC might be a good indicator of water flow change in canals.

DOI： 10.2166/wst.2014.243

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IWA PUBLISHING  

Odaiba seaside park is one of the most popular waterfronts in Tokyo Bay, but is easily affected by wet weather pollutant loads through combined sewer overflows (CSOs). The monitoring data of Escherichia coli clearly showed high faecal contamination after a rainfall event on 9-11 November 2007. We estimated the amounts of discharge volume and E. coli pollutant loads of urban rivers receiving CSO from rainfall chambers as well as pumping stations and primary effluent discharge. The result suggested that Sumida River and Meguro River were more influential to the Odaiba coastal area than other sources including the nearest wastewater treatment plant. Subsequently, we simulated the dynamic behaviour of E. coli by a three-dimensional (3D) hydro-dynamic and water quality model. The model simulation reproduced that E. coli concentration after the rainfall event increased rapidly at first and later gradually decreased. The simulations with and without inflow pollutant loads from urban rivers suggested that the E. coli concentration can be influenced by the Meguro River just after the rainfall event and Sumida River about 1 week later. From the spatial and temporal distribution of surface E. coli concentration, after at least 6 days from the rainfall event, high faecal contamination spread to the whole of the coastal area.

DOI： 10.2166/wst.2014.225

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Language：English   Publisher：Japan Society on Water Environment  

Benzene and toluene often contaminate groundwater and pose serious threat to human health due to their high toxicity. Anaerobic degradation can be a cost-effective method but the degradation mechanism remains poorly understood. We established benzene- and/or toluene-degrading bacterial cultures under methanogenic conditions from non-contaminated soil to compare their behaviour during and after enrichment. Benzene and toluene degradation rates increased during incubation, and this fact implied enrichment and/or adaptation of benzene/toluene-degrading microorganisms. The abundance of Hasda-A and/or related bacteria, defined by a primer set targeting uncultured putative benzene-degrading Desulfobacterales bacterium Hasda-A, increased only in the enrichments fed with benzene. This result indicated that Hasda-A and/or related bacteria played an important role on benzene degradation. Furthermore, to investigate the biodegradation range of benzene and toluene degraders, we added both benzene and toluene to all cultures. Toluene or benzene was also degraded by cultures that have been fed with benzene or toluene, respectively. The culture which was originally fed only with toluene had smaller benzene degradation rate than the culture fed with benzene. Similar result was obtained for toluene degradation in cultures fed with toluene or benzene. These data indicate that different microorganisms were likely involved in benzene and toluene degradation in our enrichments.

DOI： 10.2965/jwet.2014.77

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IWA PUBLISHING  

Biological activated carbon (BAC) filtration combined with preceding ozone oxidation has been established as a major advanced drinking water purification process. One of the most important functions of BAC is the biological oxidation of ammonia, which can serve as a precursor for odourous trichloramine. The activity of ammonia-oxidizing microorganisms in the BAC filter is related to the nitrification performance of BAC. In the present study, autotrophic growth competitions between ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) associated with BAC were evaluated by DNA stable isotope probing. When low levels of ammonium (0.14 mg N/L) were continuously supplied to BAC collected from a full-scale drinking water purification plant in Tokyo, AOA rather than AOB demonstrated higher autotrophic growth activity following 7 days of incubation. After 28 days, both AOA and AOB showed autotrophic growth. These results indicate that AOA outcompete AOB for the oxidation of low levels of ammonium in BAC filters.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IWA PUBLISHING  

Molecular-level characterization of dissolved organic matter (DOM) in different urban water resources (river water, groundwater, reclaimed water, and rainwater) was performed by Orbitrap Fourier transform mass spectrometry (FT-MS). The mass spectra, which were fingerprints of DOM composition, were clearly different among samples. Based on accurate molecular mass determination, about 300 molecular formulae were identified. Most of the DOM molecules were composed of carbon, hydrogen and oxygen. Molecular formulae in river water consisted of CHO mostly and much less N- and S-containing compounds than other water samples. The percentage of CHO molecules was the highest for reclaimed water. The reclaimed water sample was characterized by a few peaks with strong intensities, which were presumed to be linear alkylbenzene sulfonates, their co-products and their biodegradation products based on their molecular formulae. Some of these compounds were also detected from river water, probably indicating the impact of wastewater treatment plants located upstream of the sampling point. Orbitrap FT-MS analysis is a powerful tool to discriminate DOM composition of urban water resources.

DOI： 10.2166/ws.2014.006

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DOI： 10.1016/j.watres.2013.07.056

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DOI： 10.1016/j.geoderma.2013.07.004

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Publishing type：Part of collection (book)  

Leadership has shifted focus from the individual to the group or institute. Efforts to link leadership and the natural environment have already begun and the necessity for environmental leadership has never been higher than ever in the era of complex and evident environmental and social problems, such as climate change, global conflict, limited resources, an overwhelming amount information, etc. There is no single solution for environmental problems that can solve the conflicts of diversified community relations. Therefore, environmental leadership development is a priority element for improving the deteriorating environment. However, the current education system, especially in Asia, lacking in providing a holistic view of environmental issues, as well as inter- or trans-disciplinary and cross-cultural approaches, or a balance between the environmental, economic and social dimensions, using hands-on experience. In response, APIEL strives to fill this gap by improving education for environmental leadership with sustainability issues in mind. This chapter will review the concept of the environmental leader through a discourse on leadership. As well, it will introduce the authors' experiences in fostering environmental leader by establishing and implementing environmental leadership education over the past four years. The discourse on environmental leadership illustrates how environmental leaders have been educated to cope with emerging environmental issues. The concepts of transformational/transformative-, eco-, collective, green, and communicative leadership provide a map to understand the evolution of the theory and practice of environmental leadership education.

DOI： 10.1007/978-4-431-54340-4_2

Scopus

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DOI： 10.1111/1574-6968.12112

PubMed

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DOI： 10.1016/j.watres.2012.09.051

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PubMed

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DOI： 10.1016/j.chemosphere.2012.09.082

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PubMed

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IWA PUBLISHING  

Combined sewer overflow (CSO) from urban areas is recognized as a major pollutant source to the receiving waters during wet weather. This study attempts to categorize rainfall events and corresponding CSO behaviours to reveal the relationship between rainfall patterns and CSO behaviours in the Shingashi urban drainage areas of Tokyo, Japan where complete service by a combined sewer system (CSS) and CSO often takes place. In addition, outfalls based on their annual overflow behaviours were characterized for effective storm water management. All 117 rainfall events recorded in 2007 were simulated by a distributed model InfoWorks CS to obtain CSO behaviours. The rainfall events were classified based on two sets of parameters of rainfall pattern as well as CSO behaviours. Clustered rainfall and CSO groups were linked by similarity analysis. Results showed that both small and extreme rainfalls had strong correlations with the CSO behaviours, while moderate rainfall had a weak relationship. This indicates that important and negligible rainfalls from the viewpoint of CSO could be identified by rainfall patterns, while influences from the drainage area and network should be taken into account when estimating moderate rainfall-induced CSO. Additionally, outfalls were finally categorized into six groups indicating different levels of impact on the environment.

DOI： 10.2166/wst.2013.253

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DOI： 10.2166/wst.2013.395

Web of Science

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Language：English  

Road dust is considered to be an important source of sediment contamination in receiving water bodies; however, few studies have evaluated the toxicity of road dust to benthic organisms. This study evaluated the toxicity of road dust to a benthic ostracod, Heterocypris incongruens, using a six-day direct exposure experiment. We applied whole sediment toxicity identification evaluation (TIE) methods to identify the primary group of toxicants in road dust. Three road dust samples from Tokyo caused high ostracod mortality. The addition of hydrophobic adsorbents, Ambersorb and XAD, eliminated toxicity in all samples, suggesting that hydrophobic compounds were the main toxicants in road dust samples. A cation exchange resin, Chelex, also reduced the toxicity of two samples, although the measured concentrations of dissolved heavy metals in the test solution did not exceed the LC50 values in the literature. In addition, the sum of toxic unit (TU=measured concentration/LC50) of each individual metal which predicts the toxicity of the metal mixtures did not exceed 1.0 in all samples, suggesting that heavy metal mixtures did not have additive effects. We hypothesized that the toxicity reduction by XAD and Chelex was due to the removal of hydrophobic compounds, rather than heavy metals. Thus, a toxicity test was conducted on fractions eluted with organic solvents from the XAD and Chelex recovered from one of the road dust samples. Methanol-eluted fractions of XAD and Chelex showed 100 percent ostracod mortality, indicating that the hydrophobic organic compounds removed by these adsorbents were the principal toxicants in the road dust sample.

DOI： 10.1016/j.ecoenv.2012.12.003

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Language：English  

Eight effluent samples were collected from four conventional activated sludge wastewater treatment plants (WWTPs) to determine the complexation of Zn, Cu, Cd and Ni by dissolved organic matter (DOM) in WWTP effluent. The collected effluents were subjected to determine the labile Zn, Cu, Cd and Ni concentrations using EmporeTM chelating disk cartridge. It was observed that more than 55% of the dissolved metals were strongly complexed by ligands in the effluents. In addition, the Zn, Cu and Cd titration data obtained by square wave anodic stripping voltammetry were interpreted with Scatchard linearization to determine the conditional stability constant and the total binding site concentrations of DOM in three of the WWTP effluents. The titration data for Zn and Cu fitted to a two-ligand system while Cd data represented a one-ligand system. The conditional stability constant for Cu was greater than that for Zn with DOM in WWTP effluents. Zinc complexation parameters in natural organic matter (river water DOM and Suwanee River humic substances) were also compared with those of DOM in WWTP effluents. The results demonstrated higher stability constant and higher binding site concentrations for the DOM in WWTP effluents than the natural organic matter.

DOI： 10.2965/jwet.2013.153

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Language：English  

Twelve particle-bound polycyclic aromatic hydrocarbons (PAHs) were measured in the first flush regime of road runoff during nine events in Winterthur in Switzerland. The total PAH contents ranged from 17 to 62 μg/g. The PAH patterns measured at different time intervals during the first flush periods were very similar within each event irrespective of variation in suspended solids (SS) concentration within the first flush regime. However, the PAH patterns were different from event to event. This indicates that the environment plays an important role in PAH accumulation in SS. A toxicity identification evaluation approach using a toxicity equivalency factor (TEF) was applied to compare toxicities in the different events. The TEFs were found to be between 8 and 33 μg TEQ g(-1) (TEQ: toxic equivalent concentration). In some cases, two events having similar total PAH contents showed two fold toxicity differences.

DOI： 10.2166/wst.2013.172

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Language：Japanese   Publisher：Japan Society on Water Environment  

Elucidating the function of the microbial community in activated sludge is the key to understanding its treatment mechanism. Although the removal of organic matter is one of the major functions of a microbial community, the substrate utilization of each microorganism remains to be fully elucidated. In this study, DNA stable isotope probing (DNA-SIP) was applied to the analysis of activated sludge collected from a full-scale wastewater treatment plant to identify glucose- and acetate-assimilating bacteria. Activated sludge was fed with ¹³C-labelled glucose and ¹³C-labelled acetate individually and incubated for 60 hours. Two different substrate concentrations (100 mgC·L^-1, 1000 mgC·L^-1) with the same loading (300 mgC) were tested for glucose, while only one substrate concentration (100 mgC·L^-1, 300 mgC of loading) was tested for acetate. The DNA-SIP experiment clearly revealed that glucose was assimilated by bacteria closely related to Aeromonas, Enterobacteriaceae, and Tolumonas regardless of substrate concentration or activated sludge collected on a different day. On the other hand, a different group of bacteria closely related to Acidovorax, Acinetobacter, and Dechloromonas was identified as acetate-assimilating bacteria. Although specific glucose- and acetate-assimilating bacteria responded to glucose and acetate, most of them were not predominant in the original sludge.

DOI： 10.2965/jswe.36.77

CiNii Books

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Other Link： https://jlc.jst.go.jp/DN/JALC/10018471457?from=CiNii

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Scenario analysis of rainwater harvesting and utilization (RWHU) was performed considering various non-potable water uses in different building types over a year. Six building types were identified in the study area using GIS data: residential houses, offices, commercial buildings, restaurants, public buildings, and "others". Rainwater storage capacity was considered as 30 mm rainwater depth. Water demand for each building type was calculated as the sum of the individual water uses for toilet flushing, air conditioning, garden irrigation, and cleaning defined in this study as "miscellaneous usages". To incorporate water quality considerations, rainwater with suspended solids level of less than 2 mg l(-1) was used as the quality criterion. The RWHU scenario was compared with other storage and water use scenarios. This study quantified the rainwater availability throughout a year and its seasonal variation and consumption in each building type. The analysis clarified the effectiveness of rainwater utilization for supplementing existing water resources.

DOI： 10.1007/s11269-011-9969-9

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DOI： 10.1111/j.1574-6968.2011.02486.x

PubMed

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Aims: To investigate the prevalence, seasonality and genotype distribution of human noroviruses (NoVs) in wastewater in Japan.
Methods and Results: Influent and effluent water samples were collected monthly for a year from a wastewater treatment plant and examined for the presence of genogroups I and II (GI and GII) NoVs. Using real-time reverse transcription (RT)-PCR assays, 12 (100%) influent and six (50%) effluent samples were positive for both GI and GII NoV genomes, with a higher prevalence in winter. A total of 152 different NoV strains, comprising 84 GI and 68 GII strains, were identified using seminested RT-PCR assays followed by cloning and sequence analysis. These strains were classified into nine GI genotypes (GI/1, 2, 4, 5, 8, 9, 11, 12 and 14) and 13 GII genotypes (GII/1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 15 and 16), showing considerable genetic diversity.
Conclusions: Based on the partial capsid gene sequences, we identified a great number of NoV strains belonging to many genotypes, demonstrating that genetically diverse NoV strains are co-circulating in aquatic environments and human populations.
Significance and Impact of the Study: Our results clearly demonstrate the seasonal trend and genetic diversity of NoVs in wastewater.

DOI： 10.1111/j.1365-2672.2012.05231.x

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Publisher：8  

DOI： 10.1016/j.chemosphere.2011.11.051

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IWA PUBLISHING  

Easy-to-measure surrogate parameters for water quality indicators are needed for real time monitoring as well as for generating data for model calibration and validation. In this study, a novel linear regression model for estimating total nitrogen (TN) based on two surrogate parameters is proposed based on evaluation of pollutant loads flowing into a eutrophic lake. Based on their runoff characteristics during wet weather, electric conductivity (EC) and turbidity were selected as surrogates for particulate nitrogen (PN) and dissolved nitrogen (DN), respectively. Strong linear relationships were established between PN and turbidity and DN and EC, and both models subsequently combined for estimation of TN. This model was evaluated by comparison of estimated and observed TN runoff loads during rainfall events. This analysis showed that turbidity and EC are viable surrogates for PN and DN, respectively, and that the linear regression model for TN concentration was successful in estimating TN runoff loads during rainfall events and also under dry weather conditions.

DOI： 10.2166/wst.2012.275

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：Japanese   Publisher：Japan Society on Water Environment  

Road runoff collected in a residential area in Tokyo was analyzed to determine the concentration level and their forms of heavy metals (i.e., Ni, Cu, Zn, and Pb) and inorganic nitrogen (i.e., NO₂-N, NO₃-N, and NH₄-N). In comparison with previous literature values on highway runoff, the Ni, Cu, and Pb concentrations were to be low owing to the difference in traffic volume. However, the Zn and NO₃-N concentrations were the same as the previously reported values. In the road runoff, particulate fraction was dominant to the dissolved fraction for Ni and Pb, whereas the dissolved fraction was comparable to the particulate fraction for Cu and Zn. Nitrate in road runoff was the most dominant among the various forms of inorganic nitrogen, which accounted for 80±11% of total inorganic nitrogen. Moreover, the contributions of road surface deposits and atmospheric deposition to the heavy-metal and nitrogen load in road runoff were estimated. The results showed that a larger antecedent dry period gave a larger contribution of atmospheric deposition to the heavy-metal and nitrogen load in road runoff. The contribution of road surface deposit to heavy-metal load was larger than that to nitrogen load.

DOI： 10.2965/jswe.35.119

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DOI： 10.1128/AEM.00121-11

PubMed

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Publishing type：Research paper (scientific journal)  

Inhibitors that reduce viral nucleic acid extraction efficiency and interfere with cDNA synthesis and/or polymerase activity affect the molecular detection of viruses in aquatic environments. To overcome these significant problems, we developed a methodology for assessing nucleic acid yields and DNA amplification efficiencies for environmental water samples. This involved adding particles of adenovirus type 5 and murine norovirus and newly developed primer-sharing controls, which are amplified with the same primer pairs and result in the same amplicon sizes as the targets, to these samples. We found that nucleic acid loss during the extraction process, rather than reverse transcription-PCR (RT-PCR) inhibition, more significantly attributed to underestimation of the presence of viral genomes in the environmental water samples tested in this study. Our success rate for satisfactorily amplifying viral RNAs and DNAs by RT-PCR was higher than that for obtaining adequate nucleic acid preparations. We found that inhibitory properties were greatest when we used larger sample volumes. A magnetic silica bead-based RNA extraction method effectively removed inhibitors that interfere with viral nucleic acid extraction and RT-PCR. To our knowledge, this is the first study to assess the inhibitory properties of environmental water samples by using both control virus particles and primersharing controls. © 2011, American Society for Microbiology.

DOI： 10.1128/AEM.00077-11

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Language：English  

DOI： 10.1016/j.chemosphere.2011.04.071

J-GLOBAL

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Other Link： http://orcid.org/0000-0002-3006-7973

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ELSEVIER SCIENCE BV  

This paper reviews the outcome of field exercise 'Oasis unit' under a new postgraduate educational initiative named "Asian Program for Incubation of Environmental Leaders" (APIEL). The Oasis unit was conducted in the Heihe River basin located in the arid northwest part of China. The influence of field-oriented environmental leadership education on the development of environmental leaders was examined throughout the program. The questionnaire including leadership skills, style, and education was used to carry out a survey administered to two groups divided on the basis of field oriented educational experience. The survey compared the results of both group to evaluate how field-oriented education influenced leadership development. (C) 2011 Published by Elsevier Ltd.

DOI： 10.1016/j.sbspro.2011.03.275

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© 2011, Chinese Institute of Environmental Engineering. All rights reserved. This study was to compare the removal efficiency of assimilable organic carbon (AOC) by biological activated carbon (BAC) filtration in three advanced drinking water treatment plants in Japan. The influence of total microbial abundances and bacterial community associated with BAC on AOC removal was also investigated. Results showed that AOC concentrations were increased after ozonation treatment. BAC filtration offered high removal efficiency of AOC from 53 to 73%. The highest reduction was observed in plant A. Total microorganisms on BAC in plant A, B and C enumerated by 4',6-diamidino-2-phenylindole staining method were 4.4 × 108, 9.0 × 108 and 5.1 × 108 cells g-1 wet, respectively. Cell-specific activity of AOC removal in BAC treatment followed the order of plant A, plant C and plant B. The bacterial community structures of raw water and BAC samples were investigated by polymerase chain reaction- denaturing gradient gel electrophoresis and Terminal Restriction Fragment Length Polymorphism.Bacterial communities in raw water of all three plants were similar but significantly different from those on BAC. This suggests that community structure changes along the treatment process. Bacterial community on BAC of plant A was slightly different from those on BAC of plant B and C. The difference in service time or retention time of BAC filtration might have some influence on bacterial community structures.

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Road dust is considered an important source of sediment contamination; however, there are few studies on the toxicity of road dust on benthic organisms. This study evaluates the toxicity of road dust on the benthic ostracod, Heterocypris incongruens, through a 6-day direct exposure experiment. All six road dust samples collected in heavy traffic areas caused high mortality of the ostracod, whereas the road dust collected in a residential area did not show toxicity to the ostracod. After maintaining the mixture of road dust and water for 24 h, the toxicity of the road dust decreased significantly for three of the six samples in the heavy traffic areas, suggesting these road dust samples become less toxic in the surface runoff process. In addition, we conducted the same toxicity test on manipulated road dust using different solid/liquid ratios and holding times to evaluate the change in toxicity caused by the runoff process. Wet road dust that had been separated from a dust-water mixture after a holding time of 1 h or 24 h did not show lethal toxicity, while the water-soluble fraction of the mixture caused high mortality of the ostracod at a solid/liquid ratio of 1:2 and 1:4. However, after a 7-day holding time of the dust-water mixture, the wet road dust and the water-soluble fraction showed lethal toxicity to the ostracod. These results suggest that toxicants of road dust seemed to exist mainly in water soluble fraction eluted off by rain water; however, particle-bound fraction again showed lethal toxicity after 7 days of incubation.

DOI： 10.1016/j.scitotenv.2011.03.001

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Publisher：17  

DOI： 10.1016/j.watres.2010.07.031

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PubMed

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Publisher：17  

DOI： 10.1016/j.watres.2010.07.015

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PubMed

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2208/jscejg.66.46

J-GLOBAL

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Language：English   Publishing type：Part of collection (book)   Publisher：Elsevier  

DOI： 10.1016/B978-0-444-53199-5.00088-9

Scopus

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2166/wpt.2010.057

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IWA PUBLISHING  

Global freshwater resources are in growing demand, owing to rapid urbanization and climate change. This is particularly evident in Asian developing countries. As a result, the use of alternative water resources, such as rainwater and reclaimed water, are being considered. However, due to concerns regarding water quality, the general public is still hesitant to use these alternative resources. It is important, therefore, to develop evaluation methodologies which overcome public uncertainties over the use of community-owned water resources. This paper examines the use of water quality evaluation methodologies in Japan. The proposed method of water quality evaluation is the water quality labeling system&apos;. This method provides a good representation of the water quality in different resources. Another method used is the evaluation of CO(2) emissions through water production which provides a clear comparison between existing water supply systems and community-owned water resources. By adopting these evaluation methodologies, the public can understand the benefits and risks of using alternative water resources.

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Publisher：12  

DOI： 10.2166/wst.2010.204

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PubMed

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：English  

In-sewer deposits in combined sewer systems (CSSs) are closely related with the behavior of first foul flush and combined sewer overflows. However, the research paying attention to the role of in-sewer deposits is quite rare, furthermore, their contributions for the washoff patterns of each pollutant including pathogenic microorganisms are almost never discussed so far. The artificial flushing experiment separating the washoff of in-sewer deposits from the inflow of surface pollutants was carried out to simulate the first foul flush in a CSS. The washoff behaviors of each pollutant including bacterial indicators and enteric viruses were investigated. Several morphological analyses for the concentration and load curves of each parameter were conducted and all patterns were classified according to their washoff characteristics and first foul flush patterns. The washoff behaviors of each pollutant and microorganism are different from each other and categorized into several groups according to their (i) time-series concentration and load curves and (ii) concentration vs. flow rate curves, respectively. The first foul flush patterns of each parameter were to be categorized into typical 3 groups; strong-, partial-, and no first foul flush group. The order of these groups signifies the strength of the first foul flush phenomena and the runoff priority as well.

DOI： 10.2166/wst.2010.097

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This study was aimed at comparing the Zn and Cu binding parameters with dissolved organic matter (DOM) in road runoff, wastewater treatment plant (WWTP) effluent and influent. Conditional stability constant (K&#039;) and binding site concentration ([L]) are important to predict free or labile metal concentration and toxicity in the water environment. The values of K&#039; and [L] of three DOMs were determined by metal titration and Scatchard linearization. The Zn and Cu titration data for DOMs in WWTP effluent and influent fitted to a two-ligand model, while DOM in road runoff fitted to a single-ligand model. The order of the values of K&#039; was WWTP influent &gt; WWTP effluent &gt; road runoff both for Zn and Cu. Total ambient binding site concentration ([L(T)]) was lower in DOM of road runoff (1.4-1.5 μM) than those in DOM of WWTP effluent (1.6-2.3 μM) and influent (17-18 μM), suggesting lower metal complexation capacity in DOM of road runoff. DOM in WWTP influent was expected to bind to both Zn and Cu more strongly than that of the effluent DOM.

DOI： 10.2166/wst.2010.517

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Language：English   Publisher：Japan Society on Water Environment  

In Hanoi, the capital of Vietnam, lakes and rivers are polluted by both point pollution sources such as discharge from sewerage system; and by non-point pollution sources such as washoff from land surface and leakage from septic tanks. Several studies had mentioned about water pollution but were mainly focusing on organic pollution, feacal contamination and pollutant sources from surface runoff were not considered. To investigate the characteristics of pollutant variation in runoff water and feacal contamination by pathogenic indicators, water samples were collected in August and September 2008, by the roadside and at the inflows of lakes under wet weather condition in the downtown of Hanoi. Monitoring results showed high pollutant concentration, especially pathogenic indicators as E.coli and total coliform (TC), both in road runoff and water that flowed into lakes. Runoff water quality was much different depending on the sampling locations and patterns of rainfall. Pollutant concentration collected by the roadside tend to increase at the end of rainfall. It might be attributed to the discharge of domestic wastewater from individual households or leakage from septic systems. Time and spatial variation were much different for each event that made urban runoff water to be more difficult to control in comparison with domestic wastewater. Cluster analysis was applied to find the similarities of water quality among sampling locations. It was a useful method to find the spatial variation of pollutants and their level of pollution.

DOI： 10.2965/jwet.2010.259

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

In this study, we calculated actual evapotranspiration using a simple method with metrological data, and estimated the potential water resources of mega cities in Asia. The potential evapotranspiration was overestimated using a Hamon's equation, compared with that of a Penman's; therefore, the evapotranspiration by the Hamon's were corrected using the regression line. The amounts of the potential water resources of mega cities in Asia were large. The pre capita amounts, however,were not so much. The population of city and the district of city area affect the estimation of water balance. It is useful for the use of water resources to estimate the water balances of mega cities in Asia with the simple method in this study.

DOI： 10.11520/jshwr.20.0.24.0

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The fluorescent excitation emission matrix (FEEM) was utilized to evaluate the removal of organic matter by stabilization ponds, which consist of aeration, facultative, and oxidation ponds of a central wastewater treatment plant of an industrial estate in northern Thailand. The result shows that six fluorescent peaks of influent wastewater and effluent water after aeration, facultative, and oxidation ponds were detected from the FEEMs at 230?nmEx/295?nmEm (A), 275?nmEx/300?nmEm (B), 240?nmEx/355?nmEm (C), 280?nmEx/355?nmEm (D), 275?nmEx/410?nmEm (E) and 330?nmEx/410?nmEm (F). The putative origins of peaks A and B, C and D, and E and F were tyrosine-like, tryptophan-like, and humic and fulvic acid-like substances, respectively. The aeration pond was the main course of action used to reduce the tyrosine-like substances at peaks A and B by 88 and 52%, respectively, and tryptophan-like substances at peaks C and D by 43 and 39%, respectively. There was only a 20 per cent decrease of humic and fulvic acid-like substances at peak E and an 18 per cent decrease at peak F through the use of aeration ponds. Total per cent reductions of total fluorescent organic matter after aeration ponds; facultative ponds; and oxidation ponds were 46, 51 and 54%, respectively. These values were notably similar to the total percent reduction of DOC by the same respective processes at 54, 53, and 55%.

DOI： 10.2166/wst.2007.361

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Language：Japanese   Publisher：公益社団法人 土木学会  

始華湖は1994年12.7kmの潮受堤防竣工によって完成した人工湖である. 締切後の著しい水質悪化に伴い1997年には淡水化を断念し, 排水門による海水交換を開始したものの, 未だ水質が回復したとは言えないのが現状である. さらに周辺の工場廃水に含まれる重金属などが土砂に吸着し, 湖内に堆積する過程を通じて, 水質のみならず底質環境にも悪影響が及んでいることが懸念されている. 本研究では, 現地採取コアの重金属分析や安定同位体分析, および土砂輸送の数値解析を通して, 始華湖における堆積環境の変遷について考察する. さらに現在建設中の潮力発電施設が, 海水交換や土砂堆積へ及ぼす影響についても評価した.

DOI： 10.2208/proce1989.53.926

CiNii Research

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Language：Japanese   Publisher：日本陸水学会  

DOI： 10.14903/jslim.71.0.28.0

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

The purposes of this study are to investigate the formation and accumulation of extra-cellular polymers (ECP) by hydrogen utilizing anaerobes under high hydrogen partial pressure conditions, which are found at bottom parts of UASB reactors. Two types of enrichment culture were obtained in which hydrogen gas was intermittently replenished as a substrate with and without sulfates. One of them is an enrichment culture of hydrogen utilizing methanogen (HUM) and the other is a mixed culture of HUM and hydrogen utilizing sulfate reducing bacteria (SRB). Effects of ammonium nitrogen and cysteine on ECP formation were investigated for each culture. A remarkable accumulation of ECP by HUM was observed at the beginning of a batch experiment. in which hydrogen gas and ammonium nitrogen were sufficiently added without cysteine. However, ECPs were not significantly accumulated in the other cases for the HUM culture and all the cases for SRB. Chemical analysis of the produced ECP suggests that ECP protein was more dominant than ECP carbohydrate. HUMs played a role in producing ECP under such a special condition as well as acid producing bacteria. The experimental results suggest that ECP formation from HUM might contribute to self-granulation of sludge in UASB reactors at the bottom where high hydrogen partial pressure was established. There is also a possibility that SRB had a negative effect on sludge granulation by suppressing ECP accumulation.

DOI： 10.11532/proes1992.29.225

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

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Modified models of wash-off from roofs and roads for non-point pollution analysis during first flush phenomena (In : Urban Drainage Modeling - Proceedings of the Specialty Symposium of the World Water and Environmental Resources Congress， pp.275-286) Yasuaki Hijioka， Fumiyuki Nakajima， Hiroaki Furumai

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Modeling and field survey on wash-off behavior of suspended particles from roofs and roads (In : Urban Drainage Modeling - Proceedings of the Specialty Symposium of the World Water and Environmental Resources Congress， pp.225-237) Hiroaki Furumai， Yasuaki Hijioka， Fumiyuki Nakajima

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Language：English   Publisher：TAYLOR & FRANCIS LTD  

DOI： 10.1080/1573062X.2016.1163794

Web of Science

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Language：Japanese  

DOI： 10.1241/johokanri.60.100

J-GLOBAL

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&amp;nbsp;It has been known that in-sewer sediments significantly contribute to combined sewer overflow (CSO) loads. However, knowledge is limited on the behavior of in-sewer sediment. In this study, characteristics of the accumulation and entrainment of in-sewer sediment were analyzed in a drainage area of 42.2 km&lt;sup&gt;2&lt;/sup&gt; using a distributed sewer model based on Ackers &amp; White&#039;s theory on the sediment transport. It was found that there is a large spatial variation in the amount of sediment deposited during dry weather and entrained during wet weather. It indicated that spatial characteristics of sediment accumulation and entrainment should be considered in a sewer network in order to identify the significant sources of the CSO loads. Then the reduction of CSO loads was evaluated by removal of in-sewer sediment by flushing with water. The reduction of CSO loads by water injection for sediment flushing at 3 points was estimated and compared. The results showed that CSO loads were reduced by 18.3 % in the case of 32400 m&lt;sup&gt;3&lt;/sup&gt; of cleaning water. This study demonstrates that model analysis is useful to evaluate the effectiveness of the CSO reduction measure by the removal of in-sewer sediment by flushing with water.

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Language：English   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

DOI： 10.1016/j.watres.2015.10.063

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&amp;nbsp;Biodegradable organic matter in reclaimed water was evaluated to find strategy to control microbial regrowth. Assimilable organic carbon (AOC) was removed by activated carbon treatment, produced by ozonation, and stable in the other treatment processes. Higher AOC concentration was liable to cause microbial regrowth, and thus the regrowth can be controlled by reducing AOC concentration. Orbitrap mass spectrometer could successfully determine low molecular weight organic matters consumed by microbial regrowth by analyzing samples before and after the regrowth. The fate in the treatment processes was different among the compounds; they were either produced or removed by ozonation, or stable throughout the treatment.

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Language：Japanese   Publisher：日本微生物生態学会  

CiNii Books

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Language：Japanese   Publisher：日本微生物生態学会  

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J-GLOBAL

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CiNii Books

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Language：Japanese   Publisher：日本微生物生態学会  

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Language：Japanese   Publisher：日本微生物生態学会  

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Language：Japanese   Publisher：日本微生物生態学会  

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J-GLOBAL

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J-GLOBAL

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CiNii Books

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CiNii Books

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;Waterborne and oyster-borne diseases are great concerns in Ishinomaki coastal area because a wastewater treatment plant was unable to utilize activated sludge process after the tsunami. In this study, we detected several kinds of enteric viruses, which are one of the most probable causes of the infection, and microbial indicators in quantitative manner. Two virus concentration methods, i.e., a novel large volume method and a conventional small volume method, were performed for a comparison purpose. Efficiencies in each of nucleic acid extraction and RT-qPCR were evaluated by internal controls. Aichi viruses and GII- and GIII-F-specific RNA phages were dominantly detected. GI- and GII-noroviruses and sapoviruses, causative agents of viral gastroenteritis, were also found. Viruses and indicators seemed to diffuse from wastewater treatment plant in both horizontal and vertical directions. The large volume virus concentration method gave higher positive ratio than the small volume method. However, the virus detection was more likely to be affected by RT-PCR inhibition. High molecular weight (>10 kDa) organic compounds which absorb 254 nm ultraviolet were assumed to be causes of the inhibition. We demonstrated distributions of pathogenic viruses in Ishinomaki coastal area as well as need for methods to relieve RT-PCR inhibition efficiently.

DOI： 10.2208/jscejer.68.III_285

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Language：English   Publisher：日本微生物生態学会  

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In this study, we investigated the effects of organic acid addition and cultivation temperature on anaerobic methanogenic benzene-degrading enrichment culture which include &lt;I&gt;Syntrophobacterales&lt;/I&gt; bacterium Hasda-A, a putative benzene degrader, and its relatives. Benzoate, crotonate, fumarate and acetate, added respectively with benzene, retarded benzene degradation in all cases. However, it was implied that the addition of these organic acids may maintain the number of cells of Hasda-A and its relatives. Cultivation temperature was varied at 3&amp;deg;C intervals ranging from 25&amp;deg;C, at which we have succeeded in obtaining an anaerobic benzene degrading culture, to 37&amp;deg;C, the optimum cultivation temperature for mesophilic methanogens. It was shown that cultivation at 31&amp;deg;C or below can maintain benzene degradation rates higher than that at 34&amp;deg;C and above. In all the experiments, the number of 16S rRNA gene copy of Hasda-A and its relatives correlated with benzene degradation.

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Language：Japanese   Publisher：日本下水道協会  

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DOI： 10.2521/jswtb.46.207

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Language：English   Publisher：WILEY-BLACKWELL PUBLISHING, INC  

Aim:
To understand soil benzene monooxygenase gene diversity by clone library construction and microarray profiling.
Methods and Results:
A primer set was designed, and benzene monooxygenase gene diversity was characterized in two benzene-amended soils. The dominant sequence types in the clone libraries were distinct between the two soils, and both sequences were assigned to novel clusters. Monooxygenase gene richness and diversity increased after benzene degradation. Oligonucleotide probes for microarray analysis were designed to detect a number of sequenced clones and reported monooxygenase genes. The microarray detected several genes that were not detected in the clone libraries of the same samples. Six probes were detected in more than one soil.
Conclusions:
The primer set designed in this study successfully detected diverse benzene monooxygenase genes. The level of diversity may have increased because the degradation of benzene differed from soil to soil. Microarrays have great potential in the comprehensive detection of gene richness as well as the elucidation of key genes for degradation.
Significance and Impact of the Study:
This study introduces a new primer set that may be used to identify diverse benzene monooxygenase genes in the environment; moreover, it demonstrates the potential of microarray technology in the profiling of environmental samples.

DOI： 10.1111/j.1472-765X.2009.02764.x

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Selective sequential dissolution (SSD) and isotopic dilution are two most commonly applied techniques for the measurement of mobile fraction of heavy metal present in the urban environment This work examined the compliance between SSD proposed by the Community Bureau of Reference (BCR) and isotopic dilution technique (IDT) for determination of mobile pool of heavy metal contained in soakaway sediment, road dust, and soil sample Heavy metals (Cu, Zn, Cd and Pb) were fractionated using the three-stage BCR protocol, while isotopically exchangeable metal concentrations (E-value) were investigated through isotopic tracers ((111)Cd, (65)Cu, (207)pb and (66)Zn) In general, total contamination level, E-value and BCR exchangeable fractions of different samples followed the similar order of road dust &gt; soakaway sediment &gt; soil Results revealed that the E-value exceeded the BCR exchangeable fraction in all samples In addition, the first three fractions of BCR which have potential to become mobile under certain environmental conditions were collectively termed as "potential mobile pool" and compared with E-value It was concluded that metal extracted by weak acid underestimates the exchangeable fraction while the potential mobile pool extracted by three reagents overestimates the real mobile forms of heavy metals However, better mobility characteristics of heavy metals can be assessed by coupling information obtained through sequential extraction and isotopic exchange.

DOI： 10.2166/wst.2010.911

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Language：Japanese   Publisher：日本微生物生態学会  

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Groundwater contamination by heavy metals from infiltration facilities receiving road runoff is of potential concern. In this study, sorption tests were conducted to evaluate the influence of the water quality of road runoff, especially dissolved organic matter (DOM), on the sorption of heavy metal species by soakaway sediment. Sequential batch tests were conducted to assess metal sorption by the soakaway sediment receiving road runoff from residential and heavily trafficked areas. Ni was adsorbed by the sediment, indicating that soakaway sediments function to prevent groundwater contamination by Ni. In contrast, Zn was released from the soakaway sediment in sorption tests using heavily trafficked road dust leachates. Ni, Cu, Zn, and dissolved organic carbon concentrations were higher in soakaway sediment leachates obtained by sorption tests using heavily trafficked road dust leachates than those using residential road dust leachates, suggesting traffic activities contaminate these pollutants. A large portion of Zn, released from the soakaway sediment, existed as stable complexes. DOM in road runoff possibly enhances the release of Zn from the sediments within infiltration facilities and might cause groundwater contamination. (c) 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jhazmat.2008.08.052

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Accumulation of heavy metals at elevated concentration and potential of considerable amount of the accumulated heavy metals to reach the soil system was observed from earlier studies in soakaways sediments within an infiltration facility in Tokyo, Japan. In order to understand the competitive adsorption behaviour of heavy metals Zn, Ni and Cu in soil, competitive batch adsorption experiments were carried out using single metal and binary metal combinations on soil samples representative of underlying soil and surface soil at the site. Speciation analysis of the adsorbed metals was carried out through BCR sequential extraction method. Among the metals, Cu was not affected by competition while Zn and Ni were affected by competition of coexisting metals. The parameters of fitted &apos;Freundlich&apos; and &apos;Langmuir&apos; isotherms indicated more intense competition in underlying soil compared to surface soil for adsorption of Zn and Ni. The speciation of adsorbed metals revealed less selectivity of Zn and Ni to soil organic matter, while dominance of organic bound fraction was observed for Cu, especially in organic rich surface soil. Compared to underlying soil, the surface soil is expected to provide greater adsorption to heavy metals as well as provide greater stability to adsorbed metals, especially for Cu.

DOI： 10.2166/wst.2009.865

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We investigated the influence of surfactants such as linear alkylbenzene sulfonates (LAS) and alcohol ethoxylates (AE) on acetate uptake by polyphosphate-accumulating organisms (PAOs) under anaerobic conditions, using the phosphate requirement for acetate uptake (+Delta P/-Delta Ac ratio). In order to estimate the +Delta P/-Delta Ac ratio, anaerobic batch tests were conducted using activated sludge collected from an anaerobic/oxic sequencing batch reactor used to treat municipal wastewater continuously supplemented with a detergent containing LAS and AE. We demonstrated that LAS and AE have both positive and negative impacts on acetate uptake by PAOs. The disadvantage is that long-term exposure to the detergent inhibits acetate uptake by PAOs, thus deteriorating the efficiency, even if the surfactants are no longer present during the tests. Furthermore, the existence of LAS and/or AE with acetate further diminishes the efficiency. The advantage is that LAS and AE are potential sources of polyhydroxyalkanoate for PAOs, because acetate is produced from the surfactants under anaerobic conditions.

DOI： 10.2166/wst.2009.104

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DOI： 10.2521/jswtb.45.63

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Language：Japanese   Publisher：Japan Society on Water Environment  

A method for the specific detection of microorganisms that assimilate radioactive substrates was combined with the use of membrane arrays consisting of random genomic DNA fragment probes prepared from the original microbial community.The feasibility of this combined method was investigated in terms of specificity, sensitivity and the applicability to the analysis of environmental samples. DNA fragment probes prepared from pure cultures exhibited specific signals to their cognate targets although one probe derived from the rRNA gene was found to be cross-hybridized. Strong correlations of signal intensity with both the amount of probe spotted and the concentration of ¹⁴C-labeled DNA in the hybridization buffer were observed after hybridization with a membrane array using whole genomic DNA as probes. A membrane array was fabricated from an activated sludge sample and hybridized with ¹⁴C-DNA extracted from the same sample grown on either ¹⁴C-acetate or ¹⁴C-methanol. One out of 48 spots was detected for each target and the positions of the two spots were found to be Identical, thus indicating the specific detection of ¹⁴C-assimilating microorganisms and a microorganism capable of assimilating both acetate and methanol.

DOI： 10.2965/jswe.32.595

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Language：Japanese   Publisher：Japan Society on Water Environment  

Urban river ecosystems are under the influence of treated wastewater effluent, but the relationship between the effluent and aquatic food web has not been well understood. In the Tama River, we investigated the effects of treated wastewater on a benthic macroinvertebrate community and main food sources for aquatic organisms including periphyton and fine particulate organic matter (FPOM). After the discharge point, the nutrient concentration significantly increased, and the δ¹⁵N of periphyton increased from 4.2‰ to 14.5‰. Furthermore, FPOM collected after the discharge point and suspended solids contained in wastewater effluent showed higher δ¹⁵N values than FPOM collected from the upstream section having no treated wastewater effect. In a macroinvertebrate community, an increase in δ¹⁵N was also observed for gatherers and filterers mainly feeding on FPOM after the discharge point. These results imply that the effects of treated wastewater discharge extend to consumers in the food web structure through primary production and FPOM.

DOI： 10.2965/jswe.32.375

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Language：Japanese   Publisher：Japan Society on Water Environment  

Urban river ecosystems are under the influence of treated wastewater effluent, but the relationship between the effluent and aquatic food web has not been well understood. In the Tama River, we investigated the effects of treated wastewater on a benthic macroinvertebrate community and main food sources for aquatic organisms including periphyton and fine particulate organic matter (FPOM). After the discharge point, the nutrient concentration significantly increased, and the δ¹⁵N of periphyton increased from 4.2‰ to 14.5‰. Furthermore, FPOM collected after the discharge point and suspended solids contained in wastewater effluent showed higher δ¹⁵N values than FPOM collected from the upstream section having no treated wastewater effect. In a macroinvertebrate community, an increase in δ¹⁵N was also observed for gatherers and filterers mainly feeding on FPOM after the discharge point. These results imply that the effects of treated wastewater discharge extend to consumers in the food web structure through primary production and FPOM.

DOI： 10.2965/jswe.32.375

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Language：Japanese   Publisher：Japan Society on Water Environment  

An A/O SBR fed with acetate as the sole carbon source was operated for 183 days to examine the dynamic behavior of Candidatus 'Accumulibacter phosphatis' (Accumulibacter) in activated sludge enhancing phosphate release activity due to an increase in pH from 7.0 to 8.2. The result obtained by real-time PCR analysis showed that the copy number of Accumulibacter gradually increased until 89 days after a lag period of around 60 days. After that, polyphosphate-accumulating organisms (PAOs) other than Accumulibacter probably proliferated, considering the dynamic change in phosphate release activity. Consequently, the significant acetate uptake by PAOs likely reduced the proliferation of glycogen-accumulating organisms at high pH.

DOI： 10.2965/jswe.32.87

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Language：English   Publishing type：Book review, literature introduction, etc.   Publisher：I W A PUBLISHING  

Lead (Pb) isotopic data were used in this study to first distinguish the partitioning of anthropogenic and natural lead in different fractions, obtained by BCR sequential extraction, and then to anticipate their mixing process in the soakaway sediment of artificial infiltration facilities (AIF). Total metal content was found higher in soakaway sediment samples than that of soil. The lowest (206)Pb/(207)Pb ratios were mostly observed in exchangeable fractions of soil and sediment samples, while residual fractions mostly showed the highest (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios than those of other fractions. In general, both ratios were higher in the soil than those of sediments. Further among soil samples, residual fraction of bottom soil exhibited higher ratios than surface soil indicating higher contribution of natural lead with depth. In addition, the difference in Pb content, partitioning and its isotope signature among four sediment samples were also investigated considering their sampling locations. The plot of (206)Pb/(207)Pb versus (208)Pb/(207)Pb showed two well demarcated cluster formations by soil and sediments samples that describe the partitioning between anthropogenic and natural lead; and some points falling in between soil and sediment samples pertinently illustrated the mixing processes between these two different pools of lead.

DOI： 10.2166/wst.2009.512

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Combined sewer overflow (CSO) has been considered to be a source of pathogenic microorganisms for aquatic environment. For the effective control and treatment of CSOs, the microbial behavior in combined sewer system (CSS) needs to be investigated. In this study, whole-day extensive monitoring of indicator microorganisms and intestinal viruses in dry weather flow (DWF) was conducted at a small residential urban drainage area with CSS. All indicator bacteria represented similar diurnal variations in the two different monitoring campaigns; their concentrations gradually decreased to the minimum at the dawn (around 5 a. m.), increased sharply to the maximum around 7 to 8 a. m., and remained rather constant from noon to midnight. On the other hand, neither coliphages nor intestinal viruses showed any concentration peaks in the morning. The maximum/minimum load ratios ranged from 18 to 42 for total coliforms, fecal coliforms and E. coli, whereas those ratios for coliphages, enteroviruses and noroviruses G2 showed greater values than those for indicator bacteria. These results indicate that the diurnal variation patterns of bacterial and viral concentrations in DWF should be considered, which affect the discharge characteristics of each microorganism and the loads of bacteria and viruses in CSOs significantly vary with the overflow time as well.

DOI： 10.2166/wst.2009.732

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Fine particulate organic matter (FPOM) plays a critical role in structuring and sustaining stream food webs by providing an essential resource for various organisms. Our goal was to elucidate FPOM dynamics by determining chemical properties, microbial respiration, and in situ decomposition rates of different FPOM fractions in relation to the parent coarse particulate organic matter (CPOM). FPOM (100-500 mu m) of defined quality was produced by feeding 5 types of CPOM to shredding amphipods (Gammarus spp.): wood, filamentous green algae, and conditioned leaves of ash, alder, and oak. Feeding and defecation of Gammarus homogenized POM of the different origins in terms of proximate lignin and nutrient content. FPOM had higher lignin content (20.5-45.6%) than did parental CPOM (5.7-26.8%), whereas molar ON decreased during the conversion of CPOM (12-109) to FPOM (10-34). Microbial respiration rates on leaf-derived FPOM were lower (0.13-0.45 mg O-2 g(-1) C h(-1)) compared to rates measured for parent CPOM (0-37-0.80 mg O-2 g(-1) C h(-1)). Furthermore, microbial decomposition over 2 mo in a stream was slower for leaf-derived FPOM (k &lt; 0.0015/d) than for the parent CPOM (k=0.0013-0.0049/d), and this pattern resulted in a positive correlation between rates of microbial respiration and decomposition. Overall, our data indicate that transformation of CPOM to FPOM has a homogenizing effect toward lower C quality, which, in turn, reduces microbial activity and decomposition rate.

DOI： 10.1899/07-106.1

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Language：English   Publisher：WILEY-BLACKWELL  

Diverse environmental genes have been identified recently. To characterize their functions, it is necessary to understand which genes and what combinations of those genes are responsible for the biodegradation of soil contaminants. In this article, a 60-mer oligonucleotide microarray was constructed to simultaneously detect di- and monooxygenase genes for benzene and related compounds. In total, 148 probes were designed and validated by pure-culture hybridizations using the following criteria to discriminate between highly homologous genes: &lt;= 53-bp identities and &lt;= 25-bp continuous stretch to nontarget sequences. Microarray hybridizations were performed using PCR products amplified from five benzene-amended soils and two oil-contaminated soils. Six of the probes gave a positive signal for more than six soils; thus, they may represent key sequences for benzene degradation in the environment. The microarray developed in this study will be a powerful tool for the screening of key genes involved in benzene degradation and for the rapid profiling of benzene oxygenase gene diversity in contaminated soils.

DOI： 10.1111/j.1574-6968.2008.01223.x

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Language：English   Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG  

In situ uptake of [2,4.6,7-H-3(N)]estrone ([H-3]E1) by the major phylogenetic groups present in activated sludge samples from two different municipal wastewater treatment plants was investigated using microautoradiography-fluorescence in situ hybridization (MAR-FISH). Approximately 1-2% of the total cells confined in the samples by an EUB probe mix contributed to E1 assimilation. Almost all the detected E1-assimilating cells involved in the early phase of E1 degradation were affiliated with the Beta- and Gammaproteobacteria. In the early phase of E1 degradation, no E1-assimilating cells affiliated with the Alphaproteobacteria, Actinobacteria, the Cytophaga-flavobacterium cluster of Phylum Bacteroidetes, or the phyla Chloroflexi, Nitrospira and Planctomycetes were detected. Bacteria affiliated with the Betaproteobacteria in the shape of long rods or chains of rods were found to contribute most to in situ E1 degradation. They contributed 61% and 82% of total E1-assimilating cells in cultures from two sources of activated sludge spiked with [H-3]E1. The E1-degrading bacteria related to the Betaproteobacteria differed phylogenetically from the aerobic E1-degrading bacterial isolates reported in previous studies. In addition, MAR-FISH revealed the significant contribution of E1-degrading bacteria affiliated with the Gammaproteobacteria in the degradation of E1 in activated Sludge. (c) 2008 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.syapm.2008.03.005

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Language：English   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Groundwater replenishment by infiltration of road runoff is expected to be a promising option for ensuring a sustainable urban water cycle. In this study, we performed a soil infiltration column test using artificial road runoff equivalent to approximately 11-12 years of rainfall to evaluate the removal of pollutants by using various chemical analyses and bioassay tests. These results indicated that soil infiltration treatment works effectively to remove most of the pollutants such as organic matter (chemical oxygen demand (CODMn) and dissolved organic carbon (DOC)), P species, polycyclic aromatic hydrocarbons (PAHs), numerous heavy metals and oestrogenic activities. Bioassay tests, including algal growth inhibition test, Microtox (R) and mutagen formation potential (MFP) test, also revealed effective removal of toxicities by the soils. However, limited amounts of NO3, Mn, Ni, alkaline earth metals, perfluorooctane sulphonate (PFOS) and perfluorooctane sulphonamide (FOSA) were removed by the soils and they possibly reach the groundwater and cause contamination. (c) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.watres.2008.02.004

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Infiltration facilities are designed for both the retention of non-point pollutants and the replenishment of groundwater in urban areas. In this study, sorption tests were conducted to evaluate the speciation of heavy metals and their behaviour in infiltration facilities receiving urban road runoff containing high DOC concentrations and stable heavy metal organic complexes. Road dust and three soakaway sediments were collected from heavy traffic areas and a residential area with an infiltration-type sewerage system in Tokyo, Japan. Sequential multiple batch tests were conducted by adding prepared road dust leachate (artificial road runoff) or deionised water to soakaway sediment to obtain soakaway sediment leachate (artificial percolating water from soakaway sediment), which mimicked the sorption by sediments in soakaways receiving urban road runoff. Heavy metal speciation was assessed by means of a combination of anion-exchange resin measurements and MINTEQA2 model calculations, and further validated by chelating resin measurements. In road dust leachates and soakaway sediment leachates, Cu predominantly existed as organic complexes and carbonates, whereas most Mn, Zn and Cd were found to exist in the form of free ions and carbonate complexes. Stable organic complexes of Cu in road dust leachates were strongly adsorbed by soakaway sediments despite the limited adsorption of DOC. On the other hand, desorption of free Mn, Zn and Cd ions from the sediment receiving road dust leachates was observed, indicating that heavy metals such as Mn, Zn and Cd may ultimately reach groundwater as free ions. (c) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chemosphere.2007.08.073

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When renewing water purification facilities, it is important to select a suitable purification system that can accommodate the quality of the respective source water. The Japan Water Research Center has been collecting a large amount of water quality data from drinking-water utilities across Japan, categorising and analysing these data, and evaluating the suitability of water purification processes. Multivariate analyses such as hierarchical cluster analysis and principal component analysis were performed to investigate the relationships between the quality of source water used for water supply and various factors that affect the purification process. Based on these results, water sources throughout Japan were clearly categorised into four groups, and suitable water purification systems were identified for the different water quality groups, The results can serve as an important reference for water utilities during future facility renewal projects. © IWA Publishing 2008.

DOI： 10.2166/ws.2008.071

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Concern about the sustainability of urban water use is the strong motivation to understand the potential of rainwater use and water recycling in urbanized cities. The history of water supply in Tokyo and its experience may provide useful information to develop sustainable urban water use and find future possible tasks in rapidly growing cities. Besides, various innovative strategies to meet the current and future water demand in Tokyo may help us to consider new approaches adjusting to the developing mega cities in Asia. In this paper, the past and current practices on utilization of latent water resources such as rainwater and reclaimed wastewater in Tokyo are summarized from the viewpoint of sustainable water use.
The storage of rainwater is a useful measure for water demand in emergency cases. In addition, the rainwater use can work as a kind of environmental education to make citizens aware of sustainable urban water use. There are 850 facilities for rainwater use in Tokyo. Since reclaimed wastewater use has several benefits, a huge water volume has been utilized for various purposes such as washing, water-cooling, toilet flushing, waterway restoration and creation of recreational waterfront. From the viewpoint of human health risk, new micropollutants such as estrogens, endocrine disrupters and surfactants should be considered as quality guideline parameter besides the conventional ones. Importance of infiltration facilities should be also highlighted to secure the sound water cycle. Groundwater recharge through the infiltration facilities provide a potential storage of water resource which can be withdrawn in the future if necessary. (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.pce.2008.02.029

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Language：English   Publisher：ROYAL SOC CHEMISTRY  

The labile species of Ni, Cu, Zn, Cd, and Pb in the Tama River, an urban river in Tokyo, Japan, were measured using diffusive gradients in thin films (DGT) method under dry and wet weather conditions, and the results were compared with total dissolved concentrations in hourly samples collected in parallel. A total of 10 DGT deployments were made and 251 hourly samples were collected during 2 rounds of sampling, conducted between August and October, 2006. Two types of diffusive gradients in thin films (DGT) devices - DGT-RG for labile inorganic and DGT-APA for total (inorganic and organic) labile species - were applied throughout the samplings. The proportions of metals measured by DGT, compared with the dissolved metal concentrations (filtered using a membrane of 0.5 mu m pore size), were 38 +/- 5% (RG) and 45 +/- 8% (APA) for Ni and 45 +/- 22% (RG) and 53 +/- 23% (APA) for Zn. No labile Cu was detected throughout the sampling; Cu was assumed to be in stable complexed forms. Labile Pb was detected in 3 out of 10 deployments only; the rest were lower than the detection limit. Dissolved and labile Cd concentrations were below the detection limits. Three rain events encountered during the sampling periods were evaluated. Rains brought considerably higher loads of metals in dissolved form, and DGT measurements indicated that labile metal loads also increased. Selected DGT measurements were compared with the WHAM 6 speciation model and found to be similar to the model-computed results.

DOI： 10.1039/b709717d

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Language：Japanese   Publisher：Japan Society on Water Environment  

To investigate the behavior of heavy metals in infiltration facilities receiving urban road runoff, we performed batch tests, which mimicked the sorption of heavy-metal species in road runoff by soakaway sediments. In soakaway sediment leachates, Ni and Cu were dominantly present as stable complexes, whereas most Zn existed as free ions and labile complexes. Ni and Cu in road runoff were adsorbed by all the soakaway sediments, whereas Zn was released from some soakaway sediments. Instead of the total Zn content in the soakaway sediments, the soluble fraction of Zn (i.e., the concentration of Zn released from sediments by deionized water) was a governing factor for the sorption from soakaways receiving road runoff; however, the behavior of Ni and Cu was not well explained by the total metal content, soluble fraction, and organic content. Desorption tests are useful in identifying soakaway sediments with limited adsorption capacities for Zn. The control and management of sediments based on desorption tests would be effective in minimizing groundwater contamination by heavy metals through infiltration facilities.

DOI： 10.2965/jswe.31.685

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Language：Japanese   Publisher：Japan Society on Water Environment  

To investigate the behavior of heavy metals in infiltration facilities receiving urban road runoff, we performed batch tests, which mimicked the sorption of heavy-metal species in road runoff by soakaway sediments. In soakaway sediment leachates, Ni and Cu were dominantly present as stable complexes, whereas most Zn existed as free ions and labile complexes. Ni and Cu in road runoff were adsorbed by all the soakaway sediments, whereas Zn was released from some soakaway sediments. Instead of the total Zn content in the soakaway sediments, the soluble fraction of Zn (i.e., the concentration of Zn released from sediments by deionized water) was a governing factor for the sorption from soakaways receiving road runoff; however, the behavior of Ni and Cu was not well explained by the total metal content, soluble fraction, and organic content. Desorption tests are useful in identifying soakaway sediments with limited adsorption capacities for Zn. The control and management of sediments based on desorption tests would be effective in minimizing groundwater contamination by heavy metals through infiltration facilities.

DOI： 10.2965/jswe.31.685

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The size distributions of zinc and copper species in the effluent of a wastewater treatment plant were determined by a combination of ultrafiltration and chelating disk cartridge fractionation. The results showed that 75-87% of total Zn and 84-86% of total Cu were strongly complexed or particle-bound in the final effluents. It was also found that the major part of Cu was bound to ligands in the &lt; 500 Da fraction while the trend for Zn was not so clear and exhibited significant seasonal variability. Labile Cu and Zn were detected not only in the smallest fraction (&lt; 500 Da) but also in the larger fractions. It meant that the labile species in the effluent were not equivalent to free metal ions. Conditional stability constants and ligand concentrations were also determined from the measured metal concentrations by square wave anodic stripping voltammetry. Existence of two types of ligand for each metal was inferred from the experimental data. Conditional stability constant obtained for the stronger type Ligand of Zn was higher than that of Cu, although the estimated Ligand concentrations were almost similar.

DOI： 10.2166/wst.2008.480

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PubMed

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Language：Japanese   Publisher：Japan Society on Water Environment  

An anaerobic aerobic sequencing batch reactor was operated for 185 days using municipal wastewater supplemented with a laundry detergent including LAS and AE to examine the efficiency of acetate uptake and the availability of the surfactants as a potential PHA source of PAOs under exposure to the detergent. Over the experimental period, the phosphate requirement for acetate uptake (+ΔP/-ΔAc ratio) was estimated by an anaerobic batch test with the addition of acetate. Consequently, it was found that the exposure to the detergent deteriorated the acetate uptake efficiency of PAOs. On the other hand, even though the detergent was added as a sole carbon source in the anaerobic batch test, a significant phosphate release was observed. The organic matter originating from the detergent was then divided into acetate and other organics, and their contributions to phosphate release were estimated using activated sludge collected on the 185th day. 60% of the total released phosphate was caused by the uptake of degradation products of LAS except lower fatty acids such as acetate. Comparing the maximum amounts of released phosphate between the two anaerobic batch tests in which acetate and the detergent were used, the latter was beyond the former after the start of the detergent addition. That is, PAOs that can not utilize acetate but can utilize degradation products of LAS contributed to phosphate removal gradually.

DOI： 10.2965/jswe.31.755

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Language：Japanese   Publisher：Japan Society on Water Environment  

To protect the aquatic ecosystem, it is important to evaluate the toxicity of contaminated sediments. Moreover, the identification of chemical compounds responsible for the toxicity is needed for effective remediation. In this study, we aimed to identify the principal toxicants of urban river sediments, applying Toxicity Identification Evaluation (TIE) methods to the toxicity test with an ostracod (a benthic crustacean). The toxicity test was conducted using sediments amended with three adsorbents: Zeolite, Chelex-100 and Ambersorb-572. Four of the nine urban river sediment samples showed lethal toxicity to the ostracod, but none of the three adsorbents reduced the mortality of the ostracod. Growth inhibition was observed in all the samples; however, the addition of the carbonaceous adsorbent Ambersorb-572 suppressed the growth inhibition in the 6 samples. This indicates that hydrophobic substances in the sediments inhibit the growth of the ostracod.

DOI： 10.2965/jswe.31.671

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J-GLOBAL

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J-GLOBAL

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Language：Japanese   Publisher：日本微生物生態学会  

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Language：English   Publisher：BLACKWELL PUBLISHING  

Catechol 2,3-dioxygenase (C23O) is an extradiol dioxygenase that plays an important role in degrading aromatic compounds such as those found at polluted sites. However, little is known about the diversity of C23O genes in unpolluted environments. In such environments, various factors, including the quality and quantity of dissolved organic matter (DOM), could influence the composition and behaviour of bacterial community possessing C230 genes. We investigated C23O genes in bacteria responding to DOM from various sources in a eutrophic lake by PCR and cloning. Six microcosms filled with lake water containing indigenous bacteria and DOM from different sources were incubated for 10 days. After 1 or 2 days of incubation, C23O genes were detected in the microcosms enriched with DOM recovered from inflow river water and humus from reed grass. The sequences were very diverse but had features conserved in extradiol dioxygenases. The clone libraries generated on day 2 showed distinctive compositions among microcosms, indicating that bacteria possessing a variety of C23O genes responded differently to DOM from different sources. After 10 days of incubation, C23O genes in a previously unidentified gene cluster, 'Cluster X', became dominant in the libraries.

DOI： 10.1111/j.1574-6941.2007.00347.x

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Language：English   Publisher：SPRINGER  

We constructed a 60-mer oligonucleotide microarray on the basis of benzene monooxygenase gene diversity to develop a new technology for simultaneous detection of the functional gene diversity in environmental samples. The diversity of the monooxygenase genes associated with benzene degradation was characterized. A new polymerase chain reaction (PCR) primer set was designed using conserved regions of benzene monooxygenase gene (BO12 primer) and used for PCR-clone library analysis along with a previously designed RDEG primer which targeted the different types of benzene monooxygenase gene. We obtained 20 types of amino acid sequences with the BO12 primer and 40 with the RDEG primer. Phylogenetic analysis of the sequences obtained suggested the large diversity of the benzene monooxygenase genes. A total of 87 60-mer probes specific for each operational taxonomical unit were designed and spotted on a microarray. When genomic DNAs of single strains were used in microarray hybridization assays, corresponding sequences were successfully detected by the microarray without any false-negative signals. Hybridization with soil DNA samples showed that the microarray was able to detect sequences that were not detected in clone libraries. Constructed microarray can be a useful tool for characterizing monooxygenase gene diversity in benzene degradation.

DOI： 10.1007/s00253-007-0877-0

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PubMed

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Language：English   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Individual particles containing Cr and/or Pb and other major components were identified in road dust from a heavily used road (hereinafter 'heavy traffic road dust'), road dust from a residential area and soakaway sediment by electron probe microanalyser to locate their sources and carrier particles. Individual particles containing high levels of Cr and/or Pb (&gt;=-0.2%) were identified using wavelength dispersive spectrometry (WDS) map analysis. Chromium, Pb and other major elements were then determined by means of a combination of WDS and energy-dispersive spectrometry in all identified particles, 50 particles containing neither Cr nor Pb from each type of road dust and soakaway sediment, and yellow road line markings. WDS map analysis revealed that many particles containing both Cr and Pb were present among the identified particles in heavy traffic road dust, whereas they were minor components in road dust from the residential area and soakaway sediment. The plots of X-ray intensities of Cr vs. Pb were linear for the identified particles containing both Cr and Pb in heavy traffic road dust, and the line closely fitted the plots for the three yellow road line marking samples. Individual particles were then classified using cluster analysis of element components. The results revealed that the adsorption of source materials or released metals onto soil minerals occurred in road dust and soakaway sediment, that the yellow road line markings were sources of Cr and Pb in heavy traffic road dust, and that materials containing Fe as a major component, such as stainless steel, were additional sources of Cr in both road dust and soakaway sediment. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chemosphere.2006.11.044

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PubMed

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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To reduce the CSO (Combined Sewer Overflow) pollutant discharge, one of the effective options is cleaning of sewer pipes before rainfall events. To maximize the efficiency, identification of pipes to be cleaned is necessary. In this study, we discussed the location of pipe deposit in dry weather in a combined sewer system using a distributed model and investigated the effect of pipe cleaning to reduce the pollutant load from the CSO. First we simulated the dry weather flow in a combined sewer system. The pipe deposit distribution in the network was estimated after 3 days of dry weather period. Several specific pipes with structural defect and upper end pipes tend to have an accumulation of deposit. Wet weather simulations were conducted with and without pipe cleaning in rainfall events with different patterns. The SS loads in CSO with and without the pipe cleaning were compared. The difference in the estimated loads was interpreted as the contribution of wash-off in the cleaned pipe. The effect of pipe cleaning on reduction of the CSO pollutant load was quantitatively evaluated (e.g. the cleaning of one specific pipe could reduce 22% of total CSO load). The CSO simulations containing pipe cleaning options revealed that identification of pipes with accumulated deposit using the distributed model is very useful and informative to evaluate the applicability of pipe cleaning option for CSO pollutant reduction.

DOI： 10.2166/wst.2007.097

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Language：Japanese   Publisher：Japan Society on Water Environment  

To investigate the diurnal behavior of linear alkylbenzene sulphonates (LAS) in domestic wastewater from a residential district on a fine-weather day, wastewater was collected for 24 hours from an upper part of a combined sewer. Dissolved LAS (D-LAS) concentration and loading began to increase from early morning and reached the highest values at 9:00. Then, they gradually decreased until noon. Multi-dimensional scaling (MDS) analysis using total LAS (T-LAS) composition showed that around the peak time wastewater was largely derived from laundry. On the other hand, there were significant shifts in D-LAS concentration and loading as well as T-LAS composition on the MDS map from 12:00 to 0:00. Therefore, LAS discharge showed a marked diurnal change. In the above investigation, the LAS adsorbed onto SS (A-LAS) and the D-LAS that is commonly analyzed were assayed. As a consequence, the former occupied larger fraction than the latter. Additionally, A-LAS composition differed from D-LAS composition, because C₁₃-LAS was predominant in A-LAS, whereas C₁₁-LAS was dominated in D-LAS. From the results, it was found that using the T-LAS obtained by analyzing A-LAS as well as D-LAS was desirable, for example, to assess the environmental pollution risk caused by combined sewer overflow. Moreover, the amount of LAS discharged from household per person per day was estimated at 1.2 g · p.e^-1 · day^-1 by taking notice of T-LAS.

DOI： 10.2965/jswe.30.579

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Language：Japanese   Publisher：Japan Society on Water Environment  

We measured the mutagen formation potential (MFP) of 42 river water samples from 37 rivers throughout Japan using the Ames mutagenicity assay, to investigate the nationwide level of mutagen precursors contained in river water. The MFP of river water was highest when Salmonella typhimurium strain TA100 was used without metabolic activation. The MFPs ranged from 210 to 20,200 net rev. · l^-1 and the median was 2,520 net rev. · l^-1, which shows that the values varied greatly between samples. About 60% of the samples showed MFPs in the range from 1,500 to 3,500 net rev. · l^-1. Dissolved organic carbon (DOC), E₂₆₀, NH₄-N, NO₂-N, NO₃-N and T-N concentrations were also measured. A strong positive relationship was observed between logarithmically-transformed DOC and MFP. However, the MFP/DOC ratio varied widely from 110 to 2,160 net rev. · mg^-1. We also investigated the relationship between MFP and river basin characteristics such as population density. The results suggest that mutagen precursors are strongly influenced by human activities. In addition, rivers were classified using a cluster analysis of water qualities (MFP, DOC, E₂₆₀, NH₄-N and NO₂-N+NO₃-N).

DOI： 10.2965/jswe.30.433

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Language：English   Publisher：I W A PUBLISHING  

Heavy metals speciation analysis was carried out on sediment samples accumulated within soakaways in an old stormwater infiltration facility in Tokyo, Japan and on a soil core sample collected near the facility. Heavy metals content in soakaways sediments were much elevated compared to nearby surface soil with the content for Zn, Pb and Cd reaching about 5 to 10 times the content in surface soil. Speciation results revealed that significant amount of the accumulated heavy metals were present in potential mobile fractions, posing threat of release to underlying soil with changing environmental conditions. Detail analyses of soil characteristics indicated significant heterogeneity with depth, especially between the surface soil and underlying soil at site. Decrease in potential adsorption sites with depth was observed in case of underlying soil. Reduced adsorption capacity for heavy metals was evidenced for underlying soil when compared with surface soil. Furthermore, less capability of the soil organic matter to bind heavy metals was evidenced through speciation analyses, which raises concern over the long-term pollution retention potential of the underlying soil receiving infiltrated runoff.

DOI： 10.2166/wst.2007.746

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Language：English   Publisher：TAYLOR & FRANCIS LTD  

A long-term runoff monitoring was carried out in a highway drainage system in Winterthur, Switzerland. Several runoff quantity simulations were carried out using the distributed model 'InfoWorks-CS'. Serial rainfall monitoring data were used for investigation of water runoff behaviour from the highway. The inter-event time definition was calculated from the runoff simulation and applied for better accurate runoff volume determination. Under continuous rainfall condition, the quantity simulation showed a good agreement with the measured hydrograph. However, in some cases where rainfall was not continuous, overestimation of runoff volume and difference in peak height/timing was found after rainfall halting. It was believed that the initial/depression loss on road surface was recovered during the halting period of rainfall and caused the difference in the runoff volume and peak height/timing difference in simulation. The consideration of regenerated depression loss significantly improved runoff simulation results in the on-and-off type rainfall events. This result showed that it was essential to estimate the inter-event time definition to consider appropriateness of the initial or intermediate loss.

DOI： 10.1080/15730620601145873

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Language：Japanese   Publisher：日本下水道協会  

CiNii Books

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J-GLOBAL

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Language：Japanese   Publisher：Japanese Society of Microbial Ecology  

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J-GLOBAL

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J-GLOBAL

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

This study clarifies the relation between activity location and groundwater infiltration. A new index (water supply footprint index: WSFP) is introduced to evaluate area-based self-sufficiency of water supply by use of groundwater infiltration. Four areas with different planning conditions are designated for case studies. For present conditions, the WSFP in the planned area is higher than that of the unplanned area with farmlands. However, results show that efficiencies of improvement, by introducing a watersupply network or new facilities for infiltration, are high in the planned area than in unplanned area.

DOI： 10.2208/proer.34.507

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Di-(2-ethylhexyl) phthalate (DEHP) is widely used and abundantly exists in the environment. Due to fresh water contamination, DEHP can enter drinking water treatment and be adsorbed on solid floc generated mostly from coagulation and flocculation processes. This study aimed to quantify the distribution of DEHP in liquid/solids (floating scum, suspended solids and settled sludge) after coagulation and flocculation processes with/without bubble. For this purpose, we developed a closed jar tester to prevent DEHP volatilization and contamination from the laboratory environment. According to DEHP adsorption results, the aluminium coagulant is an important factor for DEHP adsorption and the floating solid contained more DEHP than the settled solid. 60-72% of initial DEHP was found in solid under conditions with aluminium coagulant, whereas 3-5% of initial DEHP was found in solid under the condition without coagulant. When the bubble presented, DEHP concentration in the solids in the top and middle layers increased. The 55 minutes of operation time (coagulant, flocculation and settling processes) was not long enough to achieve the equilibrium of DEHP adsorption especially in the cases with coagulant.

DOI： 10.2166/ws.2006.705

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Language：Japanese   Publisher：Japan Society on Water Environment  

Leaching tests on road dust are necessary to clarify the transport of heavy metals in water cycle in urban areas. In this study, leaching tests were conducted to evaluate the leaching characteristics of heavy metals from road dust in a heavy-traffic area and in a residential area. The results show that the leached concentrations of Cr, Fe, Ni and Cu from road dust in the heavy-traffic area were significantly higher than those from road dust in the residential area. Additionally, the leached fractions of Cr from road dust in the heavy-traffic area were also significantly larger than those from road dust in the residential area. The leached fractions of Cr from road dust seem to be derived from traffic sign markers such as yellow paint. Leaching tests on size-fractionated road dust revealed that the leached concentrations of Al, Cr, Cu, As and Cd were higher in their fine fractions (< 106 μm), whereas the leached concentrations of Mn, Zn and Pb were higher in their coarse fractions (106∼2000 μm). There were different tendencies in leaching characteristics from fine to coarse fractions among the heavy metals.

DOI： 10.2965/jswe.29.731

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

Firstly, phosphate release activity test in which commercial laundry detergents and LAS were added to an actual anaerobic aerobic activated sludge showed the increase of phosphate concentration and PHA content, and subsequent phosphate uptake activity test exhibited the remarkable decrease of phosphate concentration. Therefore, surfactant was likely to be finally accumulated as PHA. Secondly, the adsorption amount of LAS to actual anaerobic aerobic activated sludge in anaerobic tank as well as a daily change in LAS concentration of influent wastewater were examined, so that the adsorption amount of LAS in a lab activated sludge which has never been exposed by any surfactant was adjusted to the actual level by adding detergent including LAS and AE, and sole LAS. Finally, phosphate release test was conducted using the adjusted activated sludge to investigate the effect of sutfactant on acetate uptake by polyphosphate-accumulating organisms. The addition of the detergent hought the increase of acetate uptake rate and the decrease of +ΔP/-ΔAc value. On the other hand, the addition ofthe sole LAS caused respective opposite effects. In other words, LAS decreased acetate uptake rate and its energy efficiency, while AE would increase them.

DOI： 10.11532/proes1992.43.333

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Recently, it is expected to utilize reclaimed wastewater water for a new water source in urban areas. However, adequate assessment about the relative risk and the acceptance of the reclaimed wastewater should be conducted from the viewpoint of water usage. In this study, we relatively evaluated the quality of reclaimed wastewater in comparison with a "criterion" based on nationwide distribution of river water quality.<BR>At first, we selected 36 rivers with various sizes of the river basin area from all over Japan. Then, after we analyzed and collected various chemical and biological items of water quality of each river, those in the selected rivers were manipulated in the form of non-exceeding probability. The probability results were similar in key water quality items to those of all the major rivers in Japan, which suggest that the distributions of water quality items based on the selected rivers can represent all the major rivers in Japan.<BR>Next, we compared the water qualities of secondary effluent and reclaimed wastewaters treated with sand filter, ozone and soil aquifer, with the distribution of water quality of the selected rivers. For an example, estrogen-like activity of secondary effluent equivalent to over the 90th percentile of the rivers decreased to about the 40th percentile of the rivers that is medium quality level through the ozonization process or the soil aquifer treatment. The other water quality items except nitrogens were also greatly improved by the above processes to the same way.

DOI： 10.11532/proes1992.43.501

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DOI： 10.11353/sesj1988.19.445

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DOI： 10.11353/sesj1988.19.453

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Language：Japanese   Publisher：SOCIETY OF ENVIRONMENTAL SCIENCE, JAPAN  

DOI： 10.11353/sesj1988.19.425

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In streams, particulate organic matter (POM) serves as a pivotal link between dissolved nutrients, microbes and organisms at higher trophic levels. Especially in forested streams, such linkage with allochthonous POM is fundamental for saprophytic chain of stream ecosystems. Here, we reviewed current understanding of riverine POM by focusing its classification, dynamics, and ecological role in streams. Generally, coarse particulate organic matter (CPOM, &gt
1 mm) is broken down to fine particulate organic matter (FPOM, 0.45 μm-1mm) and dissolved organic matter (DOM, &lt
0.45μm) while providing essential energy and nutrients for microbes and aquatic fauna. Since input and transport of POM depend highly on season and discharge fluctuation, POM concentration in temperate streams shows wide ranges: 0.001 to 3 mgC L-1 for CPOM and 0.05 to 1 mgC L-1 for FPOM. For deposited POM density, channel unit such as riffle and pool is also influential. Major ecological roles of riverine POM are 1) habitat for aquatic fauna, 2) energy and nutrient supply for microbes, 3) energy and nutrient supply for aquatic fauna, and 4) material transport to downstream reaches and ocean. Colonization of fungi and bacteria on POM mediates carbon and nutrient uptake of aquatic fauna, especially macroinvertebrates. In stream ecosystems, therefore, POM is a major driving force and repeatedly experiences biological interaction and transformation, which is referred as organic matter spiraling. Thus, understanding of organic matter dynamics and its biological interaction is essential for conservation and restoration of stream ecosystems. © 2006, Ecology and Civil Engineering Society. All rights reserved.

DOI： 10.3825/ece.9.85

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DOI： 10.2208/jscejg.62.74

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A field investigation of infiltration facilities, built two decades ago in Tokyo, was carried out and sediment samples were collected from 12 infiltration inlets of three different locations. Heavy metals contents in the inlet sediment, road dusts and soils samples were analysed and compared. The particle size distribution analysis showed its variation in depth as well as from inlet to inlet. The nature of organic substances present in sediment found changes in particle sizes as well as in depth. The heavy metals content in the sediment samples ranged from 6-143 (Cr), 1-84 (Ni), 49-331 (Cu), 210-2186 (Zn) and 2-332 (Pb) mu g/g. The heavy metal content ranges were similar to road dust, which indicated road dust as a possible source for sediment for the infiltration inlets. The lower heavy metals content in many sediment samples than the soil indicated possible release/desorption of heavy metals under newly created environments such as an anaerobic environment. Among the heavy metals there was a relatively good relationship between Cu and Zn, indicating the existence of their common sources.

DOI： 10.2166/wst.2006.584

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An in vitro bioaccessibility test was applied for assessing the transfer of polycyclic aromatic hydrocarbons (PAHs) present in road dust, into benthic organisms living in a receiving water body. The road dust is supposed to be urban runoff particles under wet weather conditions. Sodium dodecyl sulfate (SDS) solution was used as a hypothetical gut fluid. Pyrene, fluoranthene and phenanthrene were the main PAH species in the SIDS extractable fraction of road dust, as well as the whole extract. Benzo(ghi)perylene showed relatively low concentrations in the SIDS extract in spite of a high concentration in the original dust. The PAH composition in benthic organisms (polychaetes) did not correspond with that of the surrounding sediment and the PAHs detected were also detected in high concentrations in the SDS extract of road dust. When testing the toxicity of the extracted contaminants by a standardised algal toxicity test, SIDS extracts of a detention pond sediment showed higher toxicity than the pore water of the corresponding sediment. Sediment suspension showed a comparative toxicity with 0.1% SIDS extract. From the results, the in vitro bioaccessibility test seems more suitable to evaluate the exposed contaminants than the traditional organic solvent extraction method and the SDS extracted fraction is applicable to toxicity tests reflecting the digestive process.

DOI： 10.2166/wst.2006.583

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Runoff monitoring of six rainfall events was carried out in a highway, Winterthur, Switzerland focusing on first flush (runoff volume up to 2.88 mm). Six runoff events were used to investigate the characteristics of particle-associated PAHs in first flush. The fine fraction (&lt; 45 mu m) had a relatively higher contribution than the coarse fraction. A significant contribution of the coarse fraction was observed at some periods when the runoff flow rapidly increased. Fluctuation of PAH content during a runoff event was significant in the coarse fraction and, in contrast, the PAH content in the fine fraction was less fluctuating. The weighted average PAH content in each event ranged from 17 to 62 mu g/g in total SS, from 23 to 54 mu g/g in the fine fraction and from 16 to 84 mu g/g in the coarse fraction. The loading of particle-associated PAHs from the first flush of highway runoff ranged from 0.06 to 0.22 g/ha in a total of 12 PAH species.

DOI： 10.2166/wst.2006.058

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A long-term continuous runoff monitoring was carried out in a highway in Winterthur, Switzerland. The total suspended solids (TSS) samples were fractionated into fine (&lt; 45 mu m) and coarse (&gt; 45 mu m) fraction and their washoff behavior was studied. The fine and coarse fraction showed different washoff behaviors. During the runoff the concentration of the fine fraction was less fluctuated compared to coarse. The fluctuation of the coarse fraction was more influenced by TSS concentration. The PAH content measurement in fine fraction showed less fluctuation compared to the coarse fraction. The PAH content in the coarse fraction was found decreasing with increasing the coarse fraction contribution to TSS. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.watres.2005.09.045

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Polycyclic aromatic hydrocarbons (PAHs) present in size- and density-fractionated road dust were measured to identify the important fractions in urban runoff and to analyse their sources. Road dust was collected from a residential area (Shakujii) and a heavy traffic area (Hongo Street). The sampling of road dust from the residential area was conducted twice in different seasons (autumn and winter). The collected road dust was separated into three or four size-fractions and further fractionated into light (&lt; 1.7 g/cm(3)) and heavy (&gt; 1.7 g/cm(3)) fractions by using cesium chloride solution. Light particles constituted only 4.0 +/- 1.4%, 0.69 +/- 0.03% and 3.4 +/- 1.0% of the road dust by weight for Shakujii (November), Shakujii (February) and Hongo Street, respectively but contained 28 +/- 10%, 33 +/- 3% and 44 +/- 8% of the total PAHs, respectively. The PAH contents in the light fractions were 1-2 orders of magnitude higher than those in the heavy fractions. In the light fractions, the 12PAH contents in February were significantly higher than the 12PAH contents in November (P &lt; 0.01), whereas in the heavy fractions, no significant difference was found (P &gt; 0.05). Cluster analysis revealed that there was a significant difference in the PAH profiles between locations rather than between size-fractions, density-fractions and sampling times. Multiple regression analysis indicated that asphalt/pavement was the major source of Shakujii road dust, and that tyre and diesel vehicle exhaust were the major sources of finer and coarser fractions collected from Hongo Street road dust, respectively. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chemosphere.2005.04.003

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Language：Japanese   Publisher：Japanese Society of Microbial Ecology  

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Language：Japanese   Publisher：化学工業社  

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In this study, coagulation experiments were conducted using three coagulants (ferric chloride (FC), poly ferric sulfate (PFS) and poly aluminum chloride (PAC)) to evaluate DOM (dissolved organic matter) removal performance in lake water. DOM removal was characterized not only by comprehensive indices such as dissolved organic carbon (DOC) and UV absorbance at 260nm (UVA(260)) but also by spectrofluorimetry and pyrolysis gas chromatography/mass spectrometry (py-GC/MS) analysis, which are useful techniques to obtain information on the structure of a higher percentage of DOC was removed by ferric coagulants than by the aluminum coagulant (FC: 53%, PFS: 41%, PAC: 36%). Similar trends were observed in the coagulation-induced decrease of UVA(260) and trihalomethane formation potential (THMFP). Spectrofluorimetry showed that higher concentrations of coagulant increased the removal of DOM with fluorescence components. However, fluorescence intensity was not reduced by increased coagulant concentrations at emission wavelengths shorter than 350 nm. Treatments with ferric coagulants were more effective in removing fluorescent components than PAC. Comparison of pyrochromatograms before and after coagulation revealed that the peak area of propanoic acid decreased most significantly after coagulation by FC among 16 identified fragment compounds. Four fragment compounds differed greatly in their coagulation behaviour, depending on the coagulant used.

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The Japanese Archipelago (land area: 377 880 km 2) extends over a distance of c. 2000 kin, with a maximum width of 300 km. Geologically, it is a young and tectonically very active area. Japan is a mountainous, wet and forested country, with its people concentrated in densely populated urban areas along the coast and on alluvial plains. Rivers are short (max. length: 370 km), steep, and exhibit flashy flow regimes. The river regime coefficient ranges from 200 to 400, which is up to an order-of-magnitude, higher than that of most continental rivers. Japan has a rich freshwater fauna and flora with a high proportion of endemic species. A distinct latitudinal gradient (subarctic to subtropical climate) in combination with the radial character of the river network results in high spatial differentiation of the freshwater fauna.
While water quality has improved remarkably during the past decades, Japanese rivers are still heavily impacted by canalization. loss of most dynamic flood plains, flow regulation, invasion by exotic species, and intensive urbanization. Currently 49% of the entire human population concentrates on 14% of the land, and the annual flood damage is the highest worldwide. As a consequence, major recent restoration initiatives aim to protect people and property against floods as well as simultaneously improving the ecological integrity of river ecosystems. Copyright (c) 2005 John Wiley & Sons, Ltd.

DOI： 10.1002/rra.835

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Language：English   Publisher：I W A PUBLISHING  

Although there have been simulation researches focusing on reduction of stormwater peak flow, by introduced infiltration facilities, model simulation of dynamic runoff behavior is still limited for frequently occurring rainfall events with weak intensity. Therefore, dynamic simulation was carried out in two urban drainages with infiltration facilities incorporated with a distributed model using two methods for describing functions of infiltration facilities. A method adjusting effective rainfall model gave poor simulation of runoff behavior in light rainfalls. Another method considering dynamic change of storage capacity as well as infiltration rate gave satisfactory estimation of the runoff in both drainages. In addition, assumption of facility clogging improved the agreement between measured and simulated hydrographs in small and medium-sized rainfall. Therefore, the proposed method might be useful for quantifying the,secondary effects of the infiltration facilities on groundwater recharge and urban non-point, pollutant trapping. as well as runoff reduction.

Web of Science

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Language：English   Publisher：I W A PUBLISHING  

A long-term monitoring investigation was carried out in a highway drainage system in Winterthur, Switzerland. Several runoff quality and quantity simulations were carried out using the distributed model "InfoWorks-CS". Serial rainfall monitoring data was used for investigation of SS runoff. behavior from the highway. Under continuous rainfall conditions, the quantity simulation showed a good agreement with the measured hydrograph. However, in some cases where rainfall was not continuous, overestimation of the peak height was found at the later stage after the end of the rainfall. It was believed that the initial/depression loss on the road surface was recovered during the halting period of rainfall. The consideration of regenerated depression loss significantly improved runoff simulation results in the on-and-off type rainfall events. A single event quality simulation underestimated the SS load in light rainfall events. One of the reasons was possibly inadequate consideration of pipe sediment conditions. A long term simulation was carried out to establish the initial condition of surface and pipe sediment for the target event. The newly simulated pollutograph gave a good agreement with the measured one. It revealed that it was essential to consider appropriateness of the initial condition,of pipe sediment as well as surface sediment.

Web of Science

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Language：Japanese  

CiNii Books

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DOI： 10.2208/proce1989.52.886

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

DOI： 10.2208/proce1989.52.891

CiNii Books

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Other Link： https://jlc.jst.go.jp/DN/JALC/00368607446?from=CiNii

Language：Japanese   Publisher：Japan Society of Civil Engineers  

The water environmet is one of the most important factors to indicate "Quality of Life" in neighborhood scale. This study aims to estimate the evaluation model for water environment based on the questionnaire survey in Okayama city. It is also examined that the evaluation reliability by residents for bio-chemical water quality in town stream. As the results, it is clarified that the certain amount of water flow is required to realize acceptable evaluation of water environment by neighbors. Contrarily, it is also found that higher water quality from bio-chemical points of view is not always necessary in town planning. The most significant political suggestion from the concept of water recycle is to utilize underground water resources that comes from sewage.

DOI： 10.2208/proer.33.125

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