In a year and half, the Chennai Metrowater will be equipped to supply water reclaimed from sewage to industries and save on freshwater sources. Work is under way to build tertiary treatment reverse osmosis plants with a combined capacity of 90 million litres a day (mld) at Kodungaiyur and Koyambedu.
With coastal regulation zone (CRZ) clearance obtained from the Union Ministry of Environment, Forest and Climate Change, the work to build the plant in Kodungaiyur and the pipeline to convey treated sewage to industries has picked up pace. Tertiary treatment is an advanced process that follows secondary treatment of sewage and produces quality water. Once completed in March 2019, the plants will be first-of-its-kind tertiary treatment facility in the State. According to sources in the Metrowater, it is the first time that a tertiary treatment facility of capacity of 90 mld is being set up in the country.
Nearly 8 per cent of the work to add a 45 mld tertiary treatment unit in an area spread over 10 acres in Kodungaiyur has been completed so far. The water agency is awaiting CRZ clearance to lay a 28.5-km pipeline to convey treated sewage from Kodungaiyur to nearly 23 industries, including North Chennai Thermal Power Station in Minjur, Manali and Ennore corridor.
Officials said the pipeline would be laid along the Buckingham canal and across the Ennore creek. Moreover, about 20 % of the reject water from the facility would be discharged into the Buckingham canal. The ₹235-crore project is being executed under the Tamil Nadu Sustainable Urban Development project with assistance from World Bank.
At present, about 55 mld of water is being supplied from the desalination plant in Minjur and other sources to the industries. Similarly, nearly 18 % of the project has been completed so far in Koyambedu and a 68-km pipeline is being laid to supply to industries in Sriperumbudur, Oragadam and Irungattukottai.
Currently, the 12 sewage treatment plants in the city treat 540 mld of sewage generated in Chennai. The STPs, however, have a capacity to treat 727 mld. “We are yet to work out on the rates to supply tertiary treated water to the industries,” said an official.
