American Society of Civil Engineers


Japanese Project Spirit 21: Development and Testing of CSO Treatment Technologies and Instrumentation Systems


by N. Horie, (Director, First Research Department, Japan Institute of Wastewater Engineering Technology, 1-22-8 Nishiikebukuro, Toshimaku, Tokyo 171-0021, Japan E-mail: n-horie@jiwet.or.jp), M. Kabata, (Chief Researcher, First Research Department, Japan Institute of Wastewater Engineering Technology, 1-22-8 Nishiikebukuro, Toshimaku, Tokyo 171-0021, Japan), and H. Sano, (Senior Researcher, First Research Department, Japan Institute of Wastewater Engineering Technology, 1-22-8 Nishiikebukuro, Toshimaku, Tokyo 171-0021, Japan)

pp. 1-7, (doi:  http://dx.doi.org/10.1061/40792(173)197)

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Document type: Conference Proceeding Paper
Part of: Impacts of Global Climate Change
Abstract: The early sewer systems were built in Japan as combined sewer systems(CSS), which played an important role in urban development. In recent years, significant pollution of receiving waters by combined sewer overflows (CSOs) conveying large oil balls was reported and the Ministry of Land, Infrastructure and Transport (MLIT) addressed this issue by establishing a CSS Advisory Committee with a mandate to report on CSO control. This study was followed by publications of Guidelines and Explanation of CSO control by the Japan Sewage Works. To develop appropriate technologies, MLIT initiated a project called Sewage Project, Integrated and Revolutionary Technology for the 21st Century, or SPIRIT 21. The project conducts research in the following areas of CSO treatment and instrumentation: (a) debris removal (screen), (b) high rate filtration, (c) coagulation and separation, (d) disinfection, and (e) measurement and control instrumentation. 24 technologies were proposed in all by the private industry and proceeded to field test in 13 cities. Up to Mar.2005 all technologies have been tested successfully and proposed for use in practical applications. For examples, two types of high rate filtration, ballasted clarification with microsand, and bromine disinfection. In two filtration plants, upflow filters employing special filter media and operated with or without coagulant addition, achieved suspended solids removals up to 70%, at surface load rates up to 1000 m/day. Ballasted clarification was another process successfully tested and approved for practical applications. Bromine disinfection was found feasible for use in CSO disinfection, with the main advantage of short reaction times. The project is operated in partnership of five groups: (a) MLIT — defined and promoted the project theme, (b) Academic institutions — provide technical advice for evaluation of R&D plans and results, and conduct basic research, (c) Municipalities — provide demonstration sites, (d) Private sector — propose/supply technologies, and fund and operate projects, and (e) JIWET coordinates and manages the project. MLIT started "Urgent Subsidy for CSS improvement" in 2002, that requires municipalities to submit "CSO urgent improvement plan" to MLIT by Mar.2005 Amended Ordinance of Sewerage Law stipulated structure of outlet facilities and effluent quality standard to be fulfilled within 10 years, with exception of some large cities within 20 years. The SPIRIT21 result indicate that this project succeeds in providing CSO treatment technologies to Japanese municipalities addressing CSO problems.


ASCE Subject Headings:
Combined sewers
Field tests
Japan
Overflow
Partnerships
Wastewater management
Water treatment