Earth Sciences Ministry to set up 10 MLD low temperature thermal desal plant near Chennai

C Shivakumar
Chennai:
Ministery of Earth Sciences along with Tamil Nadu government will set up a 10 MLD low temperature thermal desalination plant about 40 km from Chennai, according to Union secretary of Earth Sciences Ministry Shailesh Nayak.

Talking to Express on the sidelines of Chemtech South 2013, Nayak said that a detailed project report is being prepared by Larsen and Toubro and NIOT in this regard to set up this barge mounted desalination plant. This is a joint initiative by the Ministry of Earth Science and Tamil Nadu government, he said.

The main purpose of the plant is to meet the drinking water requirements of the city. He said the operating cost of producing per litre of water is 19 paise.

He said it would take nearly 18 months to get the DPR ready. Interestingly, this comes in the wake of four low temperature thermal desalination plant being  commissioned in the country.

Usually under this technology, warm water is flashed inside a vacuum flash chamber and the vapour produced is condensed using cold water.

The temperature difference that exists between the warm surface sea water (28 to 30 degrees Celsius) and deep sea cold water (7 to15 degrees Celsius) would be effectively utilized to produce potable water. Nayak said the thermal desalination plant does not affect the marine eco system unlike the regular desalination plants, which lets out brine.

Nayak also said that thermal desalination plant in Tuticorin would be ready in the next two to three years. This will provide two million litres of water per day, he said.

Four Low Temperature Thermal Desalination (LTTD) plants have been successfully commissioned in the country, one each at Kavaratti (2005), Minicoy (2011), Agatti (2011) islands of Lakshadweep and at North Chennai Thermal Power Station (NCTPS),
Chennai (2008). The capacity of each of these LTTD plants is 1 lakh liter of potable water per day. The capital cost of LTTD plant at Kavaratti was Rs 5 crores, at Minicoy Rs 13 crores, at Agatti Rs. 21 crores, and at NCTPS, it was Rs. 5 crores.