The Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) has started operating its tertiary treatment ultrafiltration plant (TTUF) at Nesapakkam on a trial basis and is discharging reclaimed water into Porur lake that would be used for drinking water supply in the city.
The project is aimed at creating a climate-resilient water supply infrastructure and promote indirect use of reclaimed water for domestic purposes. The TTUF plant, which has a maximum capacity to treat 10 million litres a day, is now operated up to 80% of its capacity.
The CMWSSB officials said the quality of the reclaimed water discharged into the lake during different stages of treatment be it secondary treatment and ultrafiltration or secondary treatment and then ozonation was being tested.
“We are also validating the functioning of the plant according to the design provided. The quality of recycled water produced at the plant and blended into the lake would be tested at different storage levels,” an official said. The water quality would be tested for adherence to the drinking water standards.
The TTUF plant has been constructed on the same premises that houses sewage treatment plants at Nesapakkam. As of now, nearly 90.05 mld of sewage gets secondary treatment at the plants. A portion of it will undergo tertiary and ultrafiltration treatment and conveyed to the lake. This milestone project would not only sustain the lake’s storage but ensure availability of drinking water supply to city residents.
Minister for Municipal Administration K.N. Nehru recently reviewed the operation of the ₹27.53-crore TTUF plant. Work on the six-mld treatment plant near the Porur lake has been accelerated and it would begin to function from August on a trial basis. The water agency operates a modular treatment plant with a capacity to treat four mld of water. Once the plant is ready, water drawn from Porur lake will be treated again and conveyed to the water distribution station through a 3-km pipeline.
“We are planning to create constructed wetlands in four locations of the lake to maintain the water quality even if there are any sewage outfalls. Work is being taken to divert a minimal amount of sewage entering the lake through the Kundrathur drain,” the official said.
The CMWSSB has completed 50% of the work in the second TTUF plant coming up in Perungudi and the reclaimed water would be blended in Perungudi lake. The work is expected to be completed by year end.
