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Minato-ku, Japan

Arai Y.,Tokyo Metroplitan University | Koizumi A.,Tokyo Metroplitan University | Inakazu T.,Tokyo Metroplitan University | Watanabe H.,Nihon Suido Consultants Co. | Fujiwara M.,Japan Water Research Center
Journal of Water Supply: Research and Technology - AQUA

Many of the waterworks facilities in Japan were constructed during the rapid economic growth period. Today, the deterioration and renovation of these aged facilities have become a pressing issue. There are approximately 600,000km worth of water pipelines laid out across Japan, accounting for about 70% of the nation's water-related assets (totalling ¥40 trillion). To provide water that is safe to use, it is necessary to improve and innovate water purification technologies; not only that, it is also vital to properly maintain and manage the pipelines. The current research aims to apply reliability engineering in the waterworks field as one possible approach and to show its viability; it will also obtain vital messages revealed within pipeline incident data. In other words, we collected the information concerning water distribution pipeline incidents through questionnaire surveys and then analysed the cumulative failure distribution (unreliability) by pipeline material, the failure probability density and failure rate, among others. © IWA Publishing 2010. Source

Suzuki Y.,Japan Water Research Center | Adachi W.,Japan Water Research Center | Amano M.,Nippon Jogesuido Sekkei Co. | Fujiwara M.,Nippon Jogesuido Sekkei Co.
Journal of Water Supply: Research and Technology - AQUA

In Japan, many drinking water systems were developed during the 1960s and 1970s, and a considerable proportion of them is now showing various signs of aging or seismic vulnerability. The major issue for many drinking water utilities is how to update those facilities in the best way to improve their deteriorating/insufficient performance. The existing performance assessment methods for water supply facilities need relatively high technical knowledge and they are only applicable to evaluate individual facilities. The Japan Water Research Center (JWRC) has thus developed a performance assessment method for drinking water infrastructure which requires no special technical investigation or a complicated calculation. Thus, staff of small- and medium-scale drinking water utilities can easily carry out logical function evaluation for their facilities using performance indices and answering questions on daily operation and maintenance. This development is part of the e-Pipe research project that was conducted at JWRC from 2008 through 2010 with Health and Labour Sciences Research Grants from the Ministry of Health, Labour and Welfare. © IWA Publishing 2014. Source

Kirimura A.,Japan Water Research Center | Suzuki Y.,Japan Water Research Center | Aizawa T.,Japan Water Research Center | Fujiwara M.,Japan Water Research Center | Miyajima M.,Kanazawa University
International Efforts in Lifeline Earthquake Engineering - Proceedings of the 6th China-Japan-US Trilateral Symposium on Lifeline Earthquake Engineering

As the Seismic Design Code (SDC) has revised its requirement following major earthquakes in the past decades, old water infrastructure in Japan must be seismically upgraded to keep up with the latest SDC. As a first step, such upgrade usually requires an assessment whether a specific civil structure is seismically resistant. The Detailed Evaluation Method (DEM) is wellknown as a full evaluation method, but due to its complexity and required high technical knowledge, the Simplified Evaluation Method (SEM) is normally applied to prioritize the structures for DEM testing. This simple assessment method, however, falls behind the current civil engineering technology in some respects, being thirty years old. Therefore, we propose a new SEM with a revised procedure, which adopts a three-step approach where the target structure is evaluated according to "threat of liquefaction," "year of construction" and then "structural resistibility.". Source

Kamoshita M.,Japan National Institute of Public Health | Kosaka K.,Japan National Institute of Public Health | Endo O.,Azabu University | Asami M.,Japan National Institute of Public Health | Aizawa T.,Japan Water Research Center

The mutagenic activities of 5-methyl-2-nitrophenol (5M2NP), a chlorination by-product of butamifos, its structural isomer 2-methyl-5-nitrophenol (2M5NP), and related compounds were evaluated by the Ames assay. The mutagenic activities of 5M2NP and 2M5NP were negative or not particularly high. However, those of their chlorinated derivatives were increased in Salmonella typhimurium strain TA100 and the overproducer strains YG1026, and YG1029 in the absence and/or presence of a rat liver metabolic activation system (S9 mix), particularly for YG1029. The mutagenic activities of 6-chloro-2-methyl-5-nitrophenol (6C2M5NP) in YG1029 in the absence and presence of S9 mix were 70 000 and 110 000 revertants mg -1, respectively. When nitro functions of 6C2M5NP and 4-chloro-5-methyl-2-nitrophenol (4C5M2NP) were reduced to amino functions, their mutagenic activities were markedly decreased. The mutagenic activities of 5M2NP and 4C5M2NP were lower than those of 2M5NP and 6C2M5NP, respectively. Thus, it was shown that substituent position is a key factor for the mutagenic activities of methylnitrophenols (MNPs) and related compounds. The mutagenic activities of the extracts of 2M5NP in chlorination increased early during the reaction time and then decreased. The main chlorination by-product contributing to the mutagenic activities of the extracts of 2M5NP in chlorination was 6C2M5NP. The results of chlorination of 2M5NP suggested that MNPs were present as their dichlorinated derivatives or further chlorination by-products in drinking water. © 2009 Elsevier Ltd. All rights reserved. Source

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