With freshwater resources becoming scarce in the wake of a failed monsoon, Chennai Metrowater plans to use tertiary treated waste water for city water supply on a trial basis. It may not happen this summer though.
The agency has called for bids to construct 10 mld capacity tertiary treatment plants each in Nesapakkam and Perungudi and release the recycled waste water into the Porur and Perungudi lakes. Their capacity could be scaled up to 100 mld, officials of the Metrowater said.
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There are plans to treat the water from these lakes and link it to the existing city water supply network. An additional 6-mld water treatment plant would be built near the Porur lake for the purpose. The project is being implemented based on the IIT-Madras model use of reclaimed water. The lakes, which are major resources for city water supply, are heavily monsoon dependent and fail to quench city’s thirst during drought. The government recently sanctioned ₹79 crore for various projects to augment water resources infrastructure, officials said.
“Only a negligible volume of recycled water would be discharged into the lakes as of now. For instance, the Porur lake has a capacity of 70 million cubic feet. If we release 100 mld of reclaimed water, it would be equal to 3.5 mcft only,” an official said. The water agency also has plans to construct on-site treatment plants in Retteri, Ayanambakkam and Perumbakkam.