Journal of Water and Environment Technology
Online ISSN : 1348-2165
ISSN-L : 1348-2165
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Showing 1-7 articles out of 7 articles from the selected issue
Original Articles
  • Nyimas Suryani, Atsushi Ichiki, Toshiyuki Shimizu, Sri Maryati
    Type: Original Article
    2019 Volume 17 Issue 6 Pages 375-385
    Published: 2019
    Released: December 10, 2019
    JOURNALS OPEN ACCESS

    Clean water is essential for humans, regardless of their social and economic conditions. Meanwhile, an urban kampung is typically a densely populated area in the city and consists of low-income households that cannot afford the safe water provided by formal water providers. Due to this constraint, the urban kampung of Bandung City, Indonesia has developed alternative sources of water using either deep wells or shallow dug wells. This research focuses on understanding the typology of the water supply system in this area and analysing water usage. Information regarding the current situation was obtained from field surveys, water quality tests, interviews with local stakeholders, and from questionnaires supplied to domestic respondents. The findings show that a total of 52% of the residents use communal wells or individual wells as their main water source, and the majority of the residents claim that they were satisfied with the present water supply system. However, some wells were contaminated by bacteria due to lack of water treatment systems. The data on existing usage patterns is needed as basic information to assist in the design of an improved water supply system.

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  • Miina Yanagihara, Fumiyuki Nakajima, Tomohiro Tobino
    Type: Original Article
    2019 Volume 17 Issue 6 Pages 386-394
    Published: 2019
    Released: December 10, 2019
    JOURNALS OPEN ACCESS

    Control sediment in whole-sediment toxicity testing has a wide range of properties, but the effects of the sediment composition at the molecular level have not been investigated. Therefore, we adopted a metabolomic approach to assess the effects of sediment composition at the molecular level, in particular the effects of control sediment composition on the metabolomic responses of test species under control and test conditions. The estuarine amphipod Grandidierella japonica was incubated in test chambers with four types of sediment, and the metabolomes of G. japonica were analyzed using a high-resolution mass spectrometer. Metabolomes of G. japonica exposed to a copper (Cu) solution were also obtained in the same way. We found that the metabolomic profiles were affected by the composition of the control sediment and exposure to Cu and that the exposure to Cu caused a more dominant influence than the change in the compositions of control sediments. However, the metabolites that had key roles to discriminate between the control and Cu exposure groups differed between the tested control sediments. Our results suggest that the effects of control sediment are smaller than those of toxicant exposure, and toxicity assessment using metabolomics is possible regardless of the sediment type.

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  • Shuji Fukahori, Taku Fujiwara
    Type: Original Article
    2019 Volume 17 Issue 6 Pages 395-406
    Published: 2019
    Released: December 10, 2019
    JOURNALS OPEN ACCESS

    Flexible composite sheets consisting of TiO2, zeolite, and organic polyethylene terephthalate (PET) fibers were prepared using papermaking techniques, and its strength, durability, and performance in removing sulfonamide from water were evaluated. TiO2 and zeolite powder were successfully incorporated into the sheet with high retention and a flexible, easy-to-handle, sheet-like TiO2/zeolite composite was obtained. The composite sheet is durable enough for wastewater treatment due to the inclusion of heat fusible PET fibers as a supporting matrix. The wet strength of the composite sheet was enhanced with increasing the amount of heat fusible PET fibers or drying temperature. Infrared spectroscopy revealed that the sheet strength and the integrity of the PET fibers were unaffected by exposure to ultraviolet (UV) irradiation. The TiO2/zeolite composite sheet removed sulfamethazine from water by adsorption and photocatalytic degradation and its performance was also unaffected by UV exposure.

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  • Takatoshi Fujii, Akira Umehara, Yusuke Date, Kaoru Aoki, Moemi Suzaki, ...
    Type: Original Article
    2019 Volume 17 Issue 6 Pages 407-419
    Published: 2019
    Released: December 10, 2019
    JOURNALS OPEN ACCESS

    This study aimed to identify and understand the temporal changes in the benthic ecosystem of Lake Nakaumi, which is an enclosed brackish water body, using the multivariate AZTI marine biotic index (M-AMBI) as biotic indicators and to evaluate the benthos response to the reclamation project for the lake. The monitoring data collected during 1994–2012 were used. Paraprionospio patiens, classified as second-order opportunistic species, appeared with high frequency in all the survey sites throughout the investigation period and was mostly dominant. Therefore, the variation of AMBI was small during the survey period. However, the species richness and Shannon diversity significantly increased from 1994 at the center of the lake. The benthic community of Lake Nakaumi was characterized by a coexistence of marine and brackish benthos and controlled by the Cl concentration through the change in their proportions.

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  • The-Anh Nguyen, Nguyet Thi-Minh Dao, Mitsuharu Terashima, Hidenari Yas ...
    Type: Original Article
    2019 Volume 17 Issue 6 Pages 420-431
    Published: 2019
    Released: December 10, 2019
    JOURNALS OPEN ACCESS

    In the renovation design of sedimentation tanks for the wastewater treatment plant, the small settling velocity particles should be removed to improve total suspended solids (SS) removal efficiency. Theoretically speaking, when the flow rate is constant, the increased settling area in the sedimentation tank results in high removal efficiency of small settling velocity particles. Alternatively, the SS removal efficiency increases in lamella settling tank as installing inclined plates. However, the actual effect of increased settling area due to different tank configuration to improve the removal efficiency of small settling velocity particles was not fully investigated. In this study, the computational fluid dynamics model was applied to simulate the effect of increased settling area on SS removal efficiency in three types of configuration when flow rate was remained unchanged. The simulation results show that the highest SS removal efficiency was observed in the tank with increased settling area by extending the length of the tank, in which the increased settling area contributed 69% to improve the removal efficiency of small settling velocity particles. These results have an important role in optimizing the design to enhance the SS removal efficiency of the settling tank.

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  • Kazushi Noro, Yoshinori Yabuki, Arisa Banno, Yusuke Tawa, Satoshi Naka ...
    Type: Original Article
    2019 Volume 17 Issue 6 Pages 432-447
    Published: 2019
    Released: December 10, 2019
    JOURNALS OPEN ACCESS

    This study validated the chemicals monitoring ability of a polar organic chemical integrative sampler (POCIS) under non-steady-state conditions resulting from natural disasters and environmental accidents in aquatic environments via laboratory experiments. The goal of this work was to contribute toward monitoring the actual state of chemical contamination resulting from emergencies and natural disasters. A chamber replicating the chemical contamination of an aquatic environment established by a chemical exposure assessment model was set up in a clean booth. The concentrations of seven neonicotinoid pesticides were increased to a maximum of 1,000, 100, or 10 µg/L for one day and decreased by 50% per day thereafter. A POCIS was set up with polyethersulfone as the permeation membrane and a resin (Oasis hydrophilic-lipophilic balance) as the receiving phase. Calibration tests of the POCIS were also conducted. The results of this study led to the addition of six neonicotinoid pesticides to the list of POCIS-measurable targets. The results of the chamber experiments showed that a POCIS is a good tool for chemicals monitoring under non-steady-state conditions in an aquatic environment.

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  • Takashi Daifuku, Koji Ito, Arisa Banno, Yoshinori Yabuki
    Type: Original Article
    2019 Volume 17 Issue 6 Pages 448-457
    Published: 2019
    Released: December 10, 2019
    JOURNALS OPEN ACCESS

    As environmental contamination resulting from the release of polychlorinated naphthalenes (PCNs) from landfills is of concern, methods are required to quantify PCNs in landfill leachates. In this study, an isomer-specific analytical method for the determination of PCNs in leachate samples was developed using gas chromatography/high-resolution mass spectrometry. The leachate samples were flocculated and the flocks were extracted using Dean–Stark Soxhlet extraction. The sample extracts were cleaned up automatically using SPD-600GC equipped with a multilayer silica gel column (silica gel/H2SO4 silica gel/AgNO3 silica gel) and a carbon-dispersed silica gel column. The method achieved PCN recovery rates of 81%–105% with instrument detection limits between 0.05 and 0.1 pg and method detection limits (MDLs) between 0.4 and 4 pg/L for the leachate extracts. The concentrations of PCNs in the leachate samples ranged from less than the MDL to 490 pg/L. The detected PCNs mainly consisted of low-chlorinated components, and the contents of PCNs were reduced following a water treatment process. This analytical method, which is among the most comprehensive isomer-specific methods available for PCNs at present, is based on existing techniques for the quantification of polychlorinated dioxins and furans and thus can be readily adopted by other laboratories.

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