CHENNAI: In a bid to fulfil the needs of water-intensive industries in north and east Chennai, the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) has proposed to expand the capacity of its two tertiary treatment reverse osmosis (TTRO) plants at Kodungaiyur and Koyambedu from the existing 45 MLD to 60 MLD each. This will now increase the combined capacity of the two plants from 90 MLD to 120 MLD.
The two plants, which have been under construction since June 2017, will soon be equipped to recycle an additional 30 MLD of sewage that will be collected from nearby Sewage Treatment Plants (STP). Recycled water from the these two plants will cater to the needs of industries along the Oragadam-Sriperumbadur stretch in the east and along the Manali-Ennore and Manali-Minjur stretches in the northern part of the city.
Based on an initial project proposal, Metro Water said that it would cost more than `60 crore for the construction and maintenance of both TRRO plants and its pipelines. “As this project is at a proposal stage, funds for the expansion of both plants haven’t been allocated yet. Also when the plants’ capacity is raised, the TTRO membrane will be expanded to increase reverse osmosis capacity,” said a Superintendent Engineer from Metro Water.
The official said that recycled water from Koyambedu plant would be given to SIPCOT Ltd, through which industries that want to make use of this water for their factory needs can obtain it. Similarly, secondary treated effluents from the Kodungaiyur plant will be supplied mainly to the North Chennai Thermal Power Station and CPCL and will also cater for around 16 industries near the Manali industrial belt.
The main aim of these plants is to minimise the usage of fresh water for industrial purposes by which drinking water needs of the city can be prioritised instead. “The construction work will be finished by April, 2019. But we need a period of five months for testing and commissioning the various units. So by September both plants with expanded capacity will be functional,” said the official.Currently, 36 MLD of the secondary treated effluent is supplied to industries through which a revenue of `15 crore per annum is generated.
The two plants will help to save fresh water from rain-fed lakes from where industrial hubs are presently receiving water so as to enable Metro Water to augment city water supply by equivalent quantity.The Metro Water currently operates a total of 12 STPs in four locations of Kodungaiyur, Koyambedu, Nesapakkam and Perungudi. These have a combined capacity of 727 MLD but treat only about 520 MLD on a regular basis, according to its official website. Treated sewage from STPs at Kodungaiyur and Koyambedu is sent to TTROs where it will go through three basic processes of pre-treatment, ultra filtration and reverse osmosis.
Future demand
1Chennai Metro Water has conducted a survey through ITCOT Consultancy on industries on anticipated demand of water in the Manali-Ennore corridor and Manali-Minjur corridor. The survey revealed that by 2020, a total of 70 MLD of water is required
2Currently, most of the industries in these corridors do not have independent source of water and are dependent on Metro Water for supplying of surface or treated water
3The quality of water matches with the potable water quality with turbidity less than 5, hardness less than 100 mg per litres and TDS less than 70 mg per litre and zero iron level