In a bid to reduce stress on freshwater sources, Chennai Metrowater has started a project on setting up tertiary sewage treatment plants at Kodungaiyur and Koyambedu and supply to industrial units.
Design under scrutiny
The design of the tertiary plants is under scrutiny and work to construct the 45-million litres a day facility each in Kodungaiyur and Koyambedu would begin in a couple of months, said sources in the Metrowater.
The tertiary treatment reverse osmosis facility planned in the existing sewage treatment plants (STP) in both the locations would further recycle the secondary treated sewage and supply to industrial units that require water of better quality. At present, the industrial belt in Manali, Ennore, Minjur and SIPCOT industrial park in Oragadam and Sriperumbudur are supplied with nearly 60 mld of treated sewage and drinking water. Metrowater estimates that the industrial demand in Minjur corridor alone would increase to 70 mld by 2020. The tertiary treatment plants would help reduce volume of treated sewage discharged into waterways and also meet industrial demands. Once the plants are commissioned, the volume of freshwater being provided to industries could be diverted to city households.
The new facility in Kodungaiyur would come up in an area spread over 10 acres at a cost of ₹255 crore and recycled sewage would be conveyed to industries, power plants and institutions in Manali, Ennore, Minjur corridor through a 28.5-km long pipeline, sources said.
Tamil Nadu State Coastal Management Authority has recommended the proposal to Union Ministry of Environment and Forest for approval with a few conditions on proper disposal of treated sewage and obtaining no objection certificate from Public Works Department for laying pipelines close to Buckingham canal.
World Bank aid
Similarly, the facility in Koyambedu would be built at a cost of ₹396 crore under Tamil Nadu Sustainable Urban Development Project (TNSUDP) with financial assistance from World Bank. The treated sewage from Koyambedu would be supplied to industries through a 70-km long pipeline.
At present, the city generates nearly 530 mld of sewage that gets treated in 12 STPs across the city. Though the capital investment in tertiary treatment is high than the other treatment facilities, it can be reclaimed within a decade and has many advantages, sources said. Work is expected to be completed in two years and such facilities would be set up in other STPs depending on the industrial demand.
