Nihon Suido Consultants Co.

Shinjuku, Japan

Nihon Suido Consultants Co.

Shinjuku, Japan
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Kitajima M.,University of Tokyo | Tohya Y.,Nihon University | Matsubara K.,Nihon Suido Consultants Co. | Haramoto E.,Yamanashi University | And 2 more authors.
Letters in Applied Microbiology | Year: 2010

Aims: To evaluate the reduction of human norovirus (HuNoV) by chlorine disinfection under typical drinking water treatment conditions. Methods and Results: HuNoV, murine norovirus (MNV) and poliovirus type 1 (PV1) were inoculated into treated water before chlorination, collected from a drinking water treatment plant, and bench-scale free chlorine disinfection experiments were performed for two initial free chlorine concentrations, 0·1 and 0·5 mg l-1. Inactivation of MNV reached more than 4 log 10 after 120 and 0·5 min contact time to chlorine at the initial free chlorine concentrations of 0·1 and 0·5 mg l -1, respectively. Conclusions: MNV was inactivated faster than PV1, and there was no significant difference in the viral RNA reduction rate between HuNoV and MNV. The results suggest that appropriate water treatment process with chlorination can manage the risk of HuNoV infection via drinking water supply systems. Significance and Impact of the Study: The data obtained in this study would be useful for assessing or managing the risk of HuNoV infections from drinking water exposure. © 2010 The Society for Applied Microbiology.

Kimura M.,Nihon Suido Consultants Co. | Kido Y.,Kyoto University | Nakakita E.,Nihon Suido Consultants Co.
IAHS-AISH Publication | Year: 2012

In recent times locally heavy rainfall has occurred frequently in Japan and caused serious human accidents; hence the need for flood forecasting systems has increased to reduce inundation damage. However, flood forecasting that secures lead-time for evacuations is extremely difficult because conventional radars cannot adequately measure the rainfall. Under this circumstance, X-band Polarimetrie radars have been installed, and flood forecasting with a higher accuracy is expected. In order to develop and optimize a real-time flood forecasting method for locally heavy rainfalls in urban drainage areas, we have considered several flood forecasting models with various computational accuracies and loads. Furthermore, we have evaluated these models for comprehensive prediction accuracies through case studies in an actual basin using X-band radar information. As a result, the detailed flood forecasting model might not always have the highest accuracy and the proposed simplified model which can apply the latest rainfall information with lower computational loads was effective. Copyright © 2012 IAHS Press.

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 | Year: 2010

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.

Mori S.,Nihon Suido Consultants Co. | Ihsanullah,University of Peshawar | Koizumi A.,Tokyo Metroplitan University | Maeda C.,Nihon Suido Consultants Co. | And 3 more authors.
Journal of Water Supply: Research and Technology - AQUA | Year: 2011

International discussions on the demand responsive approach (DRA) started in the mid-1990s because past supply-driven approaches had led to the failure of many water supply and sewerage/on-site sanitation (WS&S/OS) projects in developing countries (DCs). DRA has already been adopted in many WS&S/OS projects targeting a certain rural or poor urban area(s) by using various demand assessment techniques such as participatory rapid appraisal (PRA) to select optimum technical options. However, adoption of DRA in large-scale urban WS&S/OS projects (covering various areas of different socioeconomic groups with different needs) has been relatively delayed. Recently, the participatory geographic information system (PGIS) has emerged as an effective method of PRA, and high resolution satellite imagery (HRSI) has become commercially available. This paper presents a PGIS-based visual area categorization of different income groups using HRSI as a key for expediting the adoption of DRA to large-scale projects in DCs. This paper proposes an innovative pro-poor methodology of DRA for large-scale urban WS&S/OS projects. The methodology focuses on the improvement of multistage sampling in a household sample survey to plan mixed services suitable for various groups. The results of a partial application of the methodology in Pakistan are also presented. © IWA Publishing 2011.

Mashiko M.,University of Tsukuba | Fujioka M.,University of Tsukuba | Moriya K.,Nihon Suido Consultants Co. | Hagimoto T.,Hitachi River and National Highway Office | And 2 more authors.
Waterbirds | Year: 2012

Reports of hybridization among herons are not uncommon but usually document interbreeding within genera and in captivity. An inter-generic hybrid pairing between a male Little Egret (Egretta garzetta) and a female Chinese Pond Heron (Ardeola bacchus) was video-recorded in a mixed-species heronry in Japan. In June 2010, nest-building behavior and copulation by the interspecific pair were observed. In August 2010, a juvenile possessing intermediate characteristics of the two species was fed by the female Chinese Pond Heron. These observations indicated that a fertile intergeneric hybridization occurred between the two species. The Chinese Pond Heron is an irregular visitor to Japan, but has been recorded more often in recent years. A rare species such as the Chinese Pond Heron might choose heterospecific mates rather than abandoning all chances of reproduction.

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