Kavaratti: Nearly two decades after India pioneered an ocean-based desalination experiment in Lakshadweep, the technology that eased chronic drinking water shortages across the islands is entering a new phase of technological renewal.
During a visit to Kavaratti on March 6, Union Minister for Earth Sciences Jitendra Singh reviewed the functioning of the desalination facility and ongoing efforts to strengthen the ageing infrastructure that has been operating since 2005.
For many residents, the change has been visible in everyday life. Kadeeshomma, an 80-year-old resident of Kavaratti who spent her life on the island, recalls a time when access to freshwater was uncertain. A former government school teacher, she says the desalination plant transformed daily life.
“Water now flows from the tap regularly, but that was not always the case. The desalination plant has been a game changer for us,” she said, adding that with the island’s population increasing, she remains hopeful that the government will continue strengthening water infrastructure.
Officials said the review focused on improving the efficiency and durability of the existing plant while exploring technological upgrades.
The Ministry is also moving ahead with a new ocean thermal energy conversion (OTEC)–powered desalination facility at Kavaratti, a project that aims to simultaneously generate electricity and freshwater using the ocean’s natural thermal gradient.
The present system is based on a process called low-temperature thermal desalination (LTTD), an indigenous technology developed by the National Institute of Ocean Technology under the Ministry of Earth Sciences. The method converts seawater into potable water by utilising the natural temperature difference between warm surface water and colder deep-ocean water.
In the process, warm seawater is introduced into a low-pressure chamber, where it rapidly evaporates. Cold seawater drawn from depths of nearly 350–400 metres is then circulated through a condenser system, cooling the vapour and turning it into fresh water. The temperature contrast between surface waters, usually around 28°C, and much colder deep-sea water enables desalination without chemical additives or high-pressure membranes.
Engineers said the cold seawater intake is connected to the shore via a subsea pipeline that stretches several hundred metres, with pumps regulating the circulation required for continuous operation. When the Kavaratti plant was commissioned, it was designed to produce nearly 1 lakh litres of drinking water daily.
Over the years, however, prolonged exposure to harsh marine conditions and ageing equipment have reduced its output. Officials indicated that the plant now produces roughly 80,000 litres of potable water a day.