Metrowater to scale up tertiary treated water use in Chennai, says official

Chennai water agency invests in wastewater reuse and circular economy solutions to ensure sustainable water management and supply.

In a bid to overcome the challenge of inequitable water supply, the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) is investing in wastewater reuse and circular water economy solutions. The water agency is now scaling up tertiary treated water availability with more plants in the city.

At the Regional Water Summit on ‘Transforming Water Management for a Resilient Future’, organised by the Associated Chambers of Commerce and Industry of India (ASSOCHAM) in the city on Thursday, T.G. Vinay, Managing Director, CMWSSB, spoke on the challenges and the road ahead for sustainable water management.

Stressing the need for a shift towards circular water economy, where wastewater is recycled and freshwater consumption is minimised, Mr. Vinay said the CMWSSB already had a tertiary treated ultrafiltration (TTUF) plant at Nesapakkam to recharge the Porur lake, which is used to supply water to the city.

The agency is investing in more TTUF plants in Perungudi and Perumbakkam. While a 10-mld (million litres a day) TTUF plant is in the commissioning stage on Langs Garden Road in Egmore, a 5-mld plant is being built near the Villivakkam lake. A detailed project report has been readied for scaling up TTUF capacity to 110 mld in Nesapakkam and Perungudi.

Noting that the spotlight is on tertiary treated reverse osmosis wastewater for industrial supply and revenue generation, Mr. Vinay said the water agency was now in talks with organisations such as CREDAI to use treated wastewater for construction purposes and laundry, apart from district cooling systems, to reduce the burden on freshwater. The TTRO water supply from Koyambedu and Kodungaiyur also earned revenue of about ₹80 crore per year.

Though desalination has sustained water availability, there is a need to optimise freshwater sources owing to the difference in production costs. While treating 1 kilolitre of freshwater costs ₹8, production cost of desalinated water was ₹46 per kilolitre.

Chennai has come a long way in strengthening its availability of water resources. Besides exploring options to increase freshwater resources along with the Water Resources Department (WRD), the CMWSSB is also taking measures for on-demand management, such as reducing leakages, replacing pipelines of the old network, and water metering. Non-revenue water contributes 20%-30% of water supply. The water agency is planning to invest in internet of things-based management for optimal use of infrastructure, Mr. Vinay added.