Minicoy, Lakshadweep: The National Institute of Ocean Technology (Niot), a Chennai-based publicly funded research organization, is in the final stages of concluding a deal with Pune-based Kirloskar Brothers Ltd to build six desalination plants in as many islands of the archipelago in the Arabian Sea.
It will be the first time a private company is participating in a desalination technology entirely developed by a government research organization—the plants will employ the low temperature thermal desalination (LTTD) method designed by Niot.
Scientists associated with the project said each of these desalination plants would generate 100,000 litres of potable water a day, relieving pressure on the over-exploited groundwater reserves in the islands.
The project would bolster the chances of applying the technology to power plants along India’s coasts to provide potable water and be a viable alternative to the in-vogue reverse osmosis (RO) process that uses special membranes to separate minerals and salts from seawater.
Access to fresh drinking water is among India’s major woes. According to a Planning Commission report, India’s annual rainfall is 4,000 trillion litres, of which only 1,869 trillion litres are usable. Of this, less than 1,123 million litres are actually put to use and the rest is wasted.
Groundwater, which accounts for 433 million litres, contributes 70-80% of that used in farms, around 80% of the supply in rural areas, and about half of that used in cities and by industry in India.
P.K. Bansal, science minister, said given the imminent threat of climate change, renewable and “cheap techniques” such as LTTD to generate fresh water “would be among the key priorities of the government”.
Climate change, according to a report by the ministry of science and technology, already accounts for a 20% increase in water scarcity.
Demand for fresh water by the industrial sector rose from 3% of availability in 1990 to 4% in 2000, and is estimated to increase to 11.5% in 2025. Irrigation demand is projected to decline from 84% in 2000 to 73% in 2025.
LTTD involves using the differences in temperature at different depths in the sea to extract fresh water from saline water. While not a new idea, designing the components of such a plant, such as a 600-800 metre pipe to suck seawater and connecting it to 500 tonne submersible pumps, are challenging tasks that involve significant expertise and effort.
“The government will fund the project and Kirloskar’s role would essentially be that of implementing the project. They have experience in designing water pumps of various sizes and we will likely transfer technological know-how to them for the purpose,” said Shailesh Nayak, secretary, ministry of earth sciences and ocean development.
Nayak said the agreement was in the final stages of approval and not inked yet.
Niot is an autonomous body under the earth sciences ministry.
Sanjay Kirloskar, who heads Kirloskar Brothers, which has core interests in developing water supply projects, pumps, valves and hydro turbines, declined comment.
M.A. Atmanand, director at Niot, confirmed that “a private sector company would be developing these plants”, but didn’t disclose its identity.
Since 2006, the earth sciences ministry has been making concerted efforts to develop LTTD as a viable alternative to the RO technology, globally the most widely used method to extract potable water from brine. The technology’s aim, Atmanand said, is to get the private sector to adopt it for coastal power plant projects and commercial drinking water supply.
It has already commissioned two such plants in Lakshwadeep with a capacity of 100,000 litres a day—at Kavarati in 2005 and Minicoy on 22 April.
But for LTTD to be more viable than the RO technology for desalination, production costs would have to be reduced to about three paise per litre, said S. Kathiroli, former Niot director.
A million-litre-a-day plant delivers water at about six paise per litre. Scaling it 10 times will lower costs to desired levels.
But the significant cost of implementation at Rs12-20 crore per plant (on islands) and limited international adoptability remain key stumbling blocks.
In April 2007, Niot commissioned a million-litre-a-day plant on a floating barge off the Chennai coast, but it was eventually dismantled.
Nayak said the floating plant was a “proof of concept” project and not meant for commercial purposes.
Another official at the ministry of earth sciences, who didn’t want to be named, said most firms were interested in supplying purified water from the plants, than in investing money to manufacture the facilities.
A Tamil Nadu-based power plant, the North Chennai Thermal Power Station, already employs Niot and generates 250,000 litres of water a day.
The environment ministry had in an order last year recommended that thermal power projects coming up along India’s coasts use the LTTD process, as Mint has reported.
In an earlier interview, Pradeep Lenka, president and chief executive of the GVK Group, which develops power projects, said LTTD falls under the category of geothermal techniques, which are yet to be validated.
“One of the problems with geothermal approaches is that there are residues of silica and other material, which affect boilers. So all this has to be accounted for before we take up a tech. No ministry can force us on the tech to be adopted,” he said.
Sanjeev Agrawal, managing director of Amplus Infrastructure, another power project developer, is more optimistic about LTTD. “Current desalination techniques are expensive and this approach sounds reasonable,” he said. “This is a smart move by the ministry.”