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Technology Type Group
Household & community

Technological Maturity

Applicable immediately (tens of desalination plants are already in operation in Japan)

Technology Owners

Several manufacturers, etc.

Needs Addressed

The need to reduce the impacts of drought in areas that may experience drought due to climate change. The needs are particularly high on small islands and other places that have limited freshwater resources.

Adaptation Effects

Securing water resources to deal with drought resulting from climate change

Overview and Features

There are three methods of desalination:

  • Evaporation: A method to obtain fresh water by condensation of vapor made by evaporation of seawater.
  • Reverse osmosis: A method to obtain fresh water by filtering seawater under pressure using a semi-permeable membrane through which seawater cannot pass.
  • Electrodialysis: A method to obtain fresh water using a special membrane that can separate seawater into diluate and concentrate, and then extract freshwater from the diluate. This is at an experimental research stage.

Desalination plants are being introduced in the Middle East and Mediterranean region, and the reverse osmosis method in particular is spreading rapidly.

Reverse osmosis desalination system

Source: Fukuoka District Waterworks Agency

Cost

Hybrid systems that use both evaporation and reverse osmosis have attracted much attention recently due to low costs, now below US$0.5/m3 of fresh water produced. On the other hand, high oil prices and tight supplies of metal can increase operating and construction costs, so it may be difficult to keep the cost of water production low in the future.

Shuqaiq Water Production Project, Saudi Arabia (completed 2010)

An 850,000 kW power plant and 178,000 m3/day seawater-to-freshwater facilities were newly constructed in Shuqaiq (a city near the Yemen border on the Red Sea side), and in 2010 started supplying Saudi Power and Water Company under a twenty-year contract. Total project cost: About 2 billion dollars

Mesaido Industrial District Power and Water Project Water Production Project, Qatar (completed 2010)

This was a new construction of a 2,000 MW power plant in the Mesaido Industrial District near Doha in Qatar. Total project cost: About 2.3 billion dollars

Considerations (technology transfer criteria, challenges, etc.)

Key issues for the spread of these technologies include reducing the cost of producing fresh water, stabilizing plant performance, and establishing easy procedures for plant operation, maintenance and management.

Co-benefits, Suitability for Developing Countries

By securing new water resources, these technologies can make it possible to provide a stable supply of water for households and industry.

Examples

Case 1. Maintenance of electrical and piping systems for seawater desalinization equipment (Tuvalu)

  • Tuvalu has a tropical marine climate, and the capital city of Funafuti has an annual rainfall of only 3,000 mm. With the island being formed on a coral reef, a stable source of water is in scarce supply. Thus, residents rely on rainwater for almost all of their domestic needs, and the chronic water shortage makes them vulnerable to long-term droughts. As a result, the search for secure water sources besides rainwater is a critical issue.
  • Based on this situation, Japan provided a seawater desalinization plant through Grant Assistance for Grassroots Human Security Projects in the form of the Donation of Seawater Desalination Plant (1999) and Funafuti Island Water Supply Facilities Improvement Plan (2006), as a form of cooperation to provide equipment for a stable supply of water.
  • However, currently, the electrical control panel and seawater intake pump are not functioning, and the personnel of the public works bureau responsible for waterworks, and technicians including personnel from the private sector are having a difficult time making repairs. For this reason, technicians are being dispatched from Japan for capacity building of the public works bureau personnel for the proper repair, maintenance and operation of the seawater desalinization plant.

Case 2. Uminonakamichi Nata Seawater Desalination Plant (Fukuoka District Waterworks Agency)

  • The Fukuoka district has a limited amount of land suitable for dams and has few large rivers, and a declining trend in annual rainfall leads to frequent drought. Water demand has increased rapidly with urbanization and a growing population, creating challenges in finding new water resources.
  • In this context, Fukuoka district has started to develop desalination plants as a part of efforts to address its water needs.

Information Resources

Collection
Adaptation Technology Database

Efficient desalination

  • Reverse osmosis membrane technology

    Objective
    Mitigation
    Technology
    Efficient desalination
    Sea water desalination

    Membrane which permeates solvent (water) but does not permeate solute (salt). In desalination, pressure up to 10MPa is applied to seawater which enables water to pass through the revere osmosis membrane, while the salt is excluded.

    Currently, two types of material are used: bridged aromatic polyamides, and cellulose acetate. Membranes must withstand high pressure and also be resistant to fouling.

  • Desalination using low-grade thermal energy

    Technology
    Efficient desalination

    This technology presents a highly efficient desalination system that is affordable and self-sustainable. Fresh water is a scarce and valuable resource. Even though water is one of the most abundant resources covering three-fourths of the planet’s surface about 97% of this volume is saline and only 3% is fresh water suitable for humans plants and animals. Since salt and brackish water can be converted to fresh water through desalination desalination technologies are highly desirable.