Work has started to establish a tertiary treatment plant at Koyambedu. Once commissioned, this facility will help in reducing the volume of treated sewage being discharged into waterways and also meet industrial water requirement.
The plant, with a capacity to treat 45 million litres of sewage a day, will be added to the existing Koyambedu sewage treatment plant complex. The treated sewage will once again be treated to make it fit for industrial use.
In a bid to conserve fresh water resources, the State government is promoting recycling of sewage to cater to the industrial requirement. Nearly ₹395 crore has been sanctioned towards the project.
On Tuesday, Municipal Administration and Water Supply secretary Harmander Singh and Chennai Metrowater managing director Arun Roy reviewed the progress of the project.
It has been estimated that the demand for tertiary treated sewage would be 44.1 million litres a day for the existing industries at Sriperumbudur, Irungattukottai and Oragadam by 2019-2020. Besides setting up a tertiary treatment reverse osmosis plant, a 60-km pipeline would be laid to carry the treated sewage to SIPCOT industrial belt in Sriperumbudur, sources said.
In a secondary treatment plant, the biochemical oxygen (BOD) demand in sewage is reduced to 20 mg per litre from the nearly 350 mg/l found in raw sewage. This BOD content has to be further reduced to less than 1 mg/l to meet the industrial needs. Similar facilities would be set up at the Kodungaiyur STP to meet the industrial demand in Minjur belt, sources added.
