CHENNAI: With the five reservoirs supplying drinking water to the city now nearly 90% full, the Chennai Metropolitan Water Supply and Sewerage Board (Metro Water) has reduced production at its 150 MLD (million litres per day) Nemmeli desalination plant to cut operational expenses.
A senior Metro Water official told TNIE that the 150 MLD plant had recently undergone maintenance, and production has been kept at a nominal level since the works were completed. “Supplying one kilolitre of desalinated water costs between Rs 50 and Rs 60, whereas supplying lake water costs only about Rs 8 per kilolitre. Since the reservoirs have sufficient storage, the 150 MLD plant is not being run at full capacity,” he said.
According to Metro Water data, the 150 MLD desalination plant has been producing only about 50 MLD over the past few weeks, while the nearby 110 MLD plant is producing around 90 MLD. The 100 MLD desalination plant at Minjur has been under repair for several months and is expected to resume operations in a few months.
Meanwhile, Metro Water drew 402 MLD of drinking water from the Chembarambakkam water treatment plant (WTP) on February 6, compared to 266 MLD on the same day last year. On Friday, the utility (Metro Water) supplied a total of 1,233 MLD of water across the city, of which 143 MLD came from the two desalination plants at Nemmeli.
Of the five reservoirs, Poondi is at 100% capacity with 3,231 mcft (million cubic feet) of water as of Friday. Redhills and Chembarambakkam are at 88% capacity with 2,924 mcft and 3,223 mcft respectively. Kannankottai–Thervoykandigai has reached 84% of its total capacity of 500 mcft, while Cholavaram stands at about 52%. On the same date last year, the reservoirs had a combined storage of 10,392 mcft, about 112 mcft less than the present level.
For comparison, on January 2, 2019, one of the city’s worst drought years, the four reservoirs of Poondi, Cholavaram, Redhills and Chembarambakkam together held just 1,376 mcft. The Kannankottai-Thervoykandigai reservoir was not yet integrated into the drinking water network at the time.