Water scarcity always has existed somewhere in the world, but today the need for water – both for people and for industry – is growing at an alarming rate. About one-third of the countries in the world suffer from water shortage, and in 20 of these, real scarcity exists. Fortunately, the technologies of desalination (also called desalting) exist to remedy these critical problems; they are now affordable and are becoming cheaper. By 2010, there were more than 14,450 desalination plants operating in 100 countries.
Desalination can be useful in varying situations. In isolated arid places with no surface water, it can be the lifeblood of a community or industry. In less extreme situations, desalination can be a valuable addition to regular water supply, remedying shortages and providing continuous supply. Undrinkable water is classified as one of two types –brackish water in rivers, and sea water with high salinity in the oceans. The technologies and costs of desalinating these two types of water differ. Desalting seawater consumes much more energy. Once considered too expensive and energy-intensive to use on a large scale, the costs of desalinating water have declined to $0.45 (with subsidies) to $1 per square meter to produce. This is due to technological advances, such as improvements in energy efficiency by energy recovery devices, and an increase in the lifetime of desalination plants. As the price of desalinating water continues to fall, it may cost no more than freshwater extraction by 2020 in some parts of the world. Desalination is a real option for governments.
Outline of the report:
- The report
outlines the principal types of water desalination technologies in current use
– distillation or thermal (MSF – multi-stage flash distillation or MED multi-effect
desalination), including cogeneration of electricity and water; and membrane,
mainly reverse osmosis (RO), followed by electrodialysis (ED).
- The report surveys
the usage of desalination in 50 countries and summarizes regions, listing
decision-makers and customers for the technology.
- The major suppliers and manufactures of desalination equipment are listed and ranked by capacity installed.