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Seawater desalination not environment friendly: WWF

By Staff
Google Oneindia News

New Delhi, Jul 8 (UNI) India, which is looking forward to desalinate of seawater to cope with water crisis in its deficient regions, may not be opting for an environment-friendly solution, if one goes by the latest World Wildlife Fund(WWF) report.

Desalination (removing salt from sea water) to overcome the water shortage could end up worsening the water crisis, it says.

The process of desalination, which involves the filtering and evaporation of sea water, is very energy-intensive and results in significant emissions of greenhouse gases that are responsible for global warming.

Increase in global temperature will speed up the melting of ice cover and dry up sources of water, say scientists.

Moreover, one of the consequences of result of going for desalination would be a mov e away shifting of focus from the efforts to conserve water and protect water bodies, said the Report.

"The quite possibly mistaken lure of widespread water availability from desalination ... has the potential to drive a major misdirection of public attention, policy and funds away from the pressing need to use all water wisely," it said.

The issue of the discharge of waste brine into the sea by desalination plants was also of much concern.

Concentrated brine are negatively bouyant in sea water, giving them a tendency to sink and spread along the sea bottom, displacing normally saline water, which can have a devastating effect on seabottom life.

WWF has urged the need of further research into the tolerance of marine organisms and ecosystems to higher salinity and brine waste.

At present several states in the country were playing with the idea of desalination plants, but have not moved much ahead because of the high cost technology.

Tamil Nadu has, however, gone in a big way to set up desalination plants, but now wants to set up major seawater based ones.

Israel has offered technology to India to desalinate water.

Per capita availability of water in India has dipped from 6,000 cubic metres in 1947 to 1,600 cubic metres now and it is expected to go down further to 750 cubic metres by 2025.

Per capita supply of water below 1,700 cubic metres has been termed as "stress" situation, according to International norms, while less than 1,000 cubic metres was "scarcity" and less than 500 cubic metres is taken as "absolute scarcity".

The country recently set up the world's first ever low temperature thermal desalination plant (LTTD) in Kavaratti, one of the Lakshadweep islands.

The government plans to set up such plants with a capacity of ten million litres/per day on all islands and coastal areas.

All these efforts to deal with water shortage seem to be very promising, but they involve a high cost to environment, according to the Report.

According to WWF estimates, there were more than 10,000 desalination plants around the world. More such plants were likely to come up as governments seek to supply water to fast-growing arid areas in the United States, India, China and elsewhere.

The WWF said it was not totally against big plants, but wanted that they should be set up only in places where they meet a real need and must be built and operated in a manner that caused least environmental damage.

The design of the intake system should proceed from the premise that seawater was also a habitat. Outflows for concentrated brines need to avoid sensitive marine areas and incorporate adequate dilution, mixing and dispersal elements, it said.

It advised countries like Spain, Saudi Arabia, Australia and other arid regions to rely more on water conservation and recycling and avoid huge desalination projects.

The WWF is of the view that desalination has a limited place in water supply, which needs to be considered on a case to case basis in line with integrated approches to the management of water supply and demand.

''Central to such an approach is the protection of the natural assets of catchment, rivers, floodplains, lakes, wetlands, acquifers and vapour flows which ultimately provide store suuply, and purify water and provide the best and most comprehensive protection against extreme catastrophic events,'' said the Report.


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