Lakshadweep leads
The country’s first LTTD plant - with a capacity of 1 lakh litres fresh water a day - was developed and commissioned in May 2005
at Kavaratti. Prithviraj Chavan said that the plant had so far produced over 155 million litres of fresh water. Lakshadweep Islands have the advantage of ocean depth (around 500
metres) available within few hundred meters from the coast and, hence, island-based plants are possible.
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New Delhi, November 26
Scarcity of potable water could soon be a thing of the past, at least in coastal and island states. The Low Temperature Thermal Desalination System (LTTD) converts saline seawater into potable water - that too for six to seven paise a litre!
The first plant set up at Kavaratti in the Lakshadweep archipelago has been converting seawater into potable water for 10 paise a litre, Minister of Earth Sciences Prithviraj Chavan told the Rajya Sabha today. “The estimated cost of production at the demonstration plant includes electricity, capital and other fixed costs. The operational cost works out to about six-seven paise a litre,” he said.
Three similar plants of one-lakh litre per day capacity are proposed to be set up at Agatti, Androth and Minicoy in the Lakshwadeep Islands. The technology - based on indigenously designed, developed and demonstrated desalination techniques by the National Institute of Ocean Technology (NIOT) - uses warm surface seawater, flash evaporated at low pressure. The vapour is then condensed with cold deep-sea water to get potable water.
“The technology is efficient and suitable for island territories of India,” Chavan said, adding that two plants were already operational. March 2010 is the target for completion of one of the plants at Agatti while it is March 2011 for the other two. Another LTTD plant of one lakh litres per day capacity was also established at Northern
Chennai Thermal Power Station in March 2009. It uses waste heat discharge from the power plant.
A scheme is also being formulated for large-scale desalination units at coastal power plants and the remaining three islands of Lakshadweep Islands on public-private partnership basis.
Experts say global water consumption is doubling every 20 years - more that twice the rate of human population growth. The world’s water use is expected to triple in the next 50 years. Almost half of the world’s population lives in 263 international river basins, but two-thirds of these basins have no treaties to share water. The world’s population is already using about 54 per cent accessible freshwater. By 2025, the human share will be 70 per cent. If per capita consumption of water continues to rise at its current rate, humankind could be using over 90 per cent of all available freshwater within 25 years, experts say.