Chennai Metrowater is all set to start preliminary work to establish water treatment plants along three lakes in the city and use the reclaimed water for city water supply next week.
The ₹152.40-crore project, including the drawal from abandoned quarries in Erumaiyur, were inaugurated a week ago. The water agency will begin work to design the modular water treatment plants along Retteri, Ayanambakkam and Perumbakkam lakes.
A total of 30 million litres of water per day (mld) is expected to be drawn to deal with Chennai’s growing water demand.
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Each of these lakes will have an on-site plant with a capacity to treat 10 mld and the treated water will be conveyed to the existing infrastructure.
“We are planning to go for artificial wetlands wherein natural vegetation like canna plants can be used to treat the sewage flowing into the waterbodies. This will ensure that water quality does not deteriorate,” an official said.
The design of the treatment plants was approved by IIT-Madras. The water tested from the lakes was found to be fit for drinking. Officials said an additional unit of activated carbon filter would be added to prevent any emerging heavy metal contamination in the water in the future. The project aims to supply treated water of better quality that has total dissolved solids (TDS) level less than 500 mg per litre and no faecal coliform.
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Reclaimed water
In a major leap forward, the water agency also plans to add 10 mld capacity tertiary sewage treatment plants in Nesapakkam and Perungudi to further improve the quality of sewage.
The reclaimed waste water will be blended in Porur and Perungudi lakes. Water drawn from the lakes will again be treated and linked to the existing water supply network.
Two 10-mld water treatment facilities are also being designed to be set up along Porur and Perungudi lakes with the approval of IIT-Madras.
Their capacity will be enhanced later up to 100 mld as per requirements. The projects will be completed within a year.
The scheme to draw 10 mld water from abandoned quarries in Erumaiyur will take shape in three months and work on designing the alignment of the pipeline to the Chembarambakkam treatment plant is in progress.