Reclamation technologies for sewage-treated water

Needs Address

The need to reduce the impacts of drought and other threats in areas that may experience drought due to climate change.

Adaptation effects

・ Prevention of drought damage due to climate change

Overview and Features

・"Reclaimed water" refers to wastewater that has been treated with the purpose of being re-used. 
・Reclaimed water has been used to supply ambient water to restore water to the environment in urban areas, and for various uses in areas experiencing drought conditions. In recent years, people have seen the potential for the use of reclaimed water for fire fighting and fire prevention in disasters such as earthquakes and in disaster recovery. Other uses include sprinkling water on road surfaces to take advantage of its heat/cold thermal energy for local heating and cooling and to fight the heat island effect, as measures against global warming
・The use of reclaimed water can be classified generally as water for reclaimed wastewater, industrial, agricultural, and environmental uses.

Purposes of using reclaimed water

Source: "Sewage facilities plans: design guidelines and commentary (Part 1)" (2009) Japan Sewage Works Association

Cost

Treated wastewater reclamation and use at Shibaura Water Reclamation Center (Tokyo)
・Depreciation: 27 yen/m3 (facilities: 20 years)
・Operations and maintenance: 26 yen/m3 (membrane life: 5 years)
・(Cost: 260 yen/m3) Source: "Recent advances in water treatment technologies, and their applications for water re-use" (Fourth Report of Committee for Policy Assessment on Water Resource Policies)

Energy source

Electricity

Ease of maintenance

Management and maintenance technology for water quality control in the pipings and for continuous water quality monitoring are required.

Technology performance

Reclaimed water use in Japan is about 200million m³ in 2006, the rate of re-use  of treated wastewater is about 1.4%. 62% of these treated wastewater is used for scenery, recreation, and river maintenance as to be characterized as main use is for ambient water.

Table 1: Reclaimed water use in Japan (Fiscal year 2006)

Source: Report of Lecture Meetings on the State of Reuse of Treated Wastewater (April 2009) (in Japanese).

Considerations

The following issues have been identified as important for promoting the use of reclaime water:
・Clarifying the societal benefits of the use of reclaimed water
・Clarifying the scope of water reclamation as a part of sewage treatment projects
・ Understanding total costs, and consideration of ways to reduce cost burden
・ Increasing the economic benefits
・Examining the potential for private sector participation, as well as forms and criteria for  participation
・Understanding the regional stocks and flows of water resources
・Creating frameworks for the re-use of treated wastewater
・Promoting R&D to access technical and scientific knowledge

Co-benefit, suitability for developing countries

・Recycling of water resources
・Reduction of pollutant loads discharged into public waters

Information Resources

・Promoting the use of reclaimed water with a new purpose in society," Report of Lecture Meetings on the State of Reuse of Treated Wastewater (April 2009) (in Japanese).
http://www.mlit.go.jp/report/press/city13_hh_000064.html
・"Sewage facilities plans: design guidelines and commentary (Part 1)" (2009) Japan Sewage Works Association (in Japanese).
・"Recent advances in water treatment technologies, and their applications for water reclamation" (Fourth Report of Committee for Policy Assessment on Water Resource Policies) (in Japanese)
http://www.mlit.go.jp/tochimizushigen/mizsei/m_evaluation/evaluation01.html
・PUB, Singapore’s national water agency
http://www.pub.gov.sg/water/newater/Pages/default.aspx
・Groundwater replenishment system
http://www.gwrsystem.com