Desalination Technology

Desalination Technology

Desalination refers to the process by which pure water is recovered from saline water by the application of energy. The commercially relevant desalination processes are broadly classified as thermal and membrane processes.   The Low Temperature Thermal  Desalination (LTTD) is a process by which warm surface seawater is flash evaporated under low pressure and condensed with cold deep seawater, for generation of freshwater.
The ESSO has set up till date 4 Low Temperature Thermal  Desalination (LTTD) plants successfully in the country,  one each at Kavaratti, Minicoy, Agatti, Lakshadweep and at Northern Chennai Thermal Power Station (NCTPS), Chennai. The technology is completely indigenous, robust   and environment friendly. Out of this four plants, the Minicoy and Agatti plants were established in April 2011 and July 2011, respectively. The capacity of each of these LTTD plants is 1 lakh litre per day of potable water. According to the cost estimates made recently by an independent agency for LTTD technology, the operational costs per litre  of desalinate water currently works to be 19 paise.   The ESSO had earlier demonstrated a LTTD offshore desalination Plant of 1 MLD capacity in April 2009 about 40 km off Chennai on a barge.  It is now proposed to demonstrate a 10 MLD offshore plant.  Currently, a project document of 10-MLD plant is being prepared after conducting the prefeasibility studies. The LTTD technology does not require any chemical pre and post-treatment of seawater.  Due to the safe drinking water which is being supplied by the Desalination Plant in Kavaratti since May 2005, the waterborne diseases,  have come down to less than 10 percent.   This technology has now been stabilized and uses very low amount of electricity and is being operated by local people.