Work to construct Chennai’s fourth desalination plant at Perur at full swing

Construction of Chennai's fourth desalination plant at Perur is underway, with a capacity to treat 400 mld of seawater.

Work is in full swing to construct the city’s fourth desalination plant at Perur along East Coast Road (ECR), just a few kilometres away from the existing plant at Nemmeli.

Even as the third desalination plant, with a capacity to treat 150 million litres of seawater a day (mld) at Nemmeli, is all set to be inaugurated in a few weeks, civil work has been started to build the facility at Perur, which may be the largest desalination plant in Southeast Asia.

The seawater reverse osmosis (RO) desalination plant will have two 200-mld units, having the capacity to treat 400 mld in total. This will ensure that the plant produces 200 mld of treated water at any point of time, said officials of the Chennai Metropolitan Water Supply and Sewerage Board or Metrowater.

Excavation work to build various units, such as intake sump and treated water storage system, has started. Moreover, work to build a compound wall and provide separate access to two burial grounds at the site is also in progress.

The new plant will have various components such as lamellar clarifier units, dissolved air flotation to remove lighter materials, such as algae and oil, and gravity dual media filters (GDMF) to separate total suspended solids in the seawater. The pre-treatment process, particularly GDMF units, added in the Perur plant will be more efficient in removing the finer particle impurities from raw water. The pre-filtration units have been fine tuned for this purpose.

With the plant expected to be an energy guzzler, there are plans to install energy recovery devices and booster pumps to save on power.

The ₹4,276-crore plant will also incorporate the recommendations of the National Institute of Ocean Technology (NIOT) regarding environmental concerns, including an erosion management plan. Diffusers have been incorporated in the brine (reject water) outfall system for marine life protection as recommended by NIOT. They will slow the release of brine and disperse the high salt concentration over a wider space so as to avoid impacting the local ecosystem negatively, officials said.