The floating pump house deployed in Porur lake as part of the project to promote use of recycled water. | Photo Credit: K. PICHUMANI

Chennai first tertiary treatment ultrafiltration (TTUF) plant will be commissioned at Nesapakkam by this month end. The pilot project is expected to promote indirect use of recycled water in the city and recharge groundwater.

Considered a major landmark in the promotion of sustainable water supply and implemented by the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB), the plant with a capacity to treat 10 million litres a day will be on trial run. The network to convey the treated water to Porur lake is ready, said sources in the board.

With an aim to create climate-resilient water infrastructure, the board had devised the project that would conserve lake’s storage, minimise stress on freshwater sources and promote indirect use of reclaimed water.

The board would draw the blended water from the lake and feed it into the existing supply network after another round of treatment.

As part of the project, the CMWSSB has deployed a floating pump house in Porur lake to draw water even from deep portions of the waterbody that has a storage capacity of 70 million cubic feet.

Sources said initially, the TTUF plant would be operated to 50% of its capacity and the quantum of water released into the lake would vary depending on the sewage discharge and the level in the lake. The plant would use major processes of pre-chlorination, ozonation and ultraviolet filtration for disinfection.

Conveyed through a 12-km pipeline, the treated water would be released into five chambers along the lake. This process would help dissipate velocity of the flow, reduce turbidity of the water and minimise soil erosion, the officials said.

The board hopes to reduce pollution in the lake after the plant at Nesapakkam is commissioned. There are plans to create constructed wetlands along the bund. This is expected to prevent encroachment of the waterbody.

Water table in localities in a radius of minimum 5-km may improve once the project becomes operational.

About 50% of the work has been completed on another 10 MLD TTUF plant coming up in Perungudi. The treater water from this plant would be released into Perungudi lake. Though work was started a few years ago, the pandemic had delayed its completion.

A team from IIT Madras, which provided the design of both the plants, would study the impact of the use of recycled water on the water table and the quality in the lake, the officials added.

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Printable version | May 12, 2022 11:24:56 pm | https://www.thehindu.com/news/cities/chennai/citys-first-tertiary-treatment-ultrafiltration-plant-ready/article65407768.ece