A potable solution

Since installing the first one in the Andamans in 1946, India has set up over 190 desalination plants, with a total capacity of over 1.60 million cubic metres a day as of 2013. The desalination market has been growing at an annual rate of over 15 per cent over the last five years and touched $520 million in 2013.

The market is set to grow at an annual rate of around 22 per cent for the next five years, according to TechSci Research, a global market research firm.

While the market is large, it is dominated by a few global firms, since setting up desalination plants is a highly specialised field that requires large-scale technology and project management expertise.

The technology of separating brine from sea water to make it potable is expensive and energy-intensive.

Rich gulf countries, such as Saudi Arabia, use it extensively, accounting for over half the world’s desalination capacity. The estimated cost of a 150-million-litre-a-day facility, to be set up near Chennai, is ₹1,000 crore.

A method known as ‘thermal desalination’ is being worked on by the Ministry of Earth Sciences, with a litre of water costing around 19 paise. Costs, particularly in reverse osmosis systems, have been coming down in recent years. Cities such as Chennai are also experimenting with public-private partnerships.

For instance, IVRCL has built a desalination plant near Chennai on a build, own, operate, transfer basis. The cost of water would be ₹48 per thousand litres. Around 100 million litres a day of water is produced out of 275 million litres of seawater.

Solar power is also now being tried to reduce operating costs. For example, Kotri village in Rajasthan’s Ajmer district uses it to filter the brackish water from Sambhar lake.

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