Nemmeli desalination plants to ramp up production amid dipping storage in Chennai’s reservoirs

With storage in the city reservoirs falling sharply, Chennai Metrowater is looking to optimise its available water resources to maintain a stable daily water supply. This includes maximising production from the desalination plants at Nemmeli.

Works to replace reverse osmosis membranes, a crucial component in the desalination process, would be completed at the 110-mld and 150-mld Nemmeli desalination plant by October end and November end respectively, according to Metrowater.

The five reservoirs supplying drinking water to the city currently have a combined storage of nearly 36.3% of their total capacity as on Thursday (October 8). Their combined storage is nearly 3,840 million cubic feet of storage lower than the storage recorded on the same day last year.

The water agency has assessed that Chennai’s daily water supply can be sustained for another five months with available water resources, including in Veeranam tank. Metrowater is hoping that the ensuing Northeast monsoon would boost the reservoirs’ storage by the year end.

Officials noted that of the water supply system’s designed capacity of 1,712 million litres a day, Chennai is being supplied with 1,272 mld of drinking water now. Of this, the desalination plants at Nemmeli contributed to 175-180 mld that is nearly 15% of the total demand.

At the 110 mld desalination plant, nearly 6,543 reverse osmosis membranes have been replaced out of the total 7,056 RO membranes over the past two years. The plant is now producing 95 mld of drinking water and is expected to achieve full capacity by the month end.

Similarly, the 150 mld plant in the same site is now producing 85 mld. The components, which are being sourced from Netherlands, Germany, and the U.S., however, could not be delivered on time due to geo-political issues. This had delayed increasing drinking water production. Now, the contractors have airlifted the RO and ultra filtration membranes to replace the old ones.

The 150 mld is expected to reach its full capacity by November end once the membranes are replaced. As of now, the desalination plants are catering to south Chennai and southern suburbs. Once the 150 mld is operated to its full capacity, additional water would be conveyed to the network supplying central parts of the city, officials said.

Meanwhile, water from the abandoned quarries in Sikkarayapuram and Erumaiyur is also being pumped for use in the city water supply, officials added.