Water-starved Delhi, which has to depend on its neighbours – and to some extent on a rapidly diminishing groundwater supply – has turned to Singapore for its NEWater – treated waste water that is collected through the Deep Tunnel Sewerage System (DTSS), an underground network, built with an eye on the future.
Singapore relies on neighbour Malaysia for about 40% of its water consumption but the agreement will end in 50 years. Anticipating a crunch, the Singapore Water Reclamation Study was initiated in 1998 as a joint initiative between the Public Utilities Board (PUB), the national water agency, and the ministry of environment and water resources. Now there are five NEWater plants that cater to about 30% of the demand. It’s also investing in desalination.
“Because of its highgrade quality, most of the NEWater is used for wafer fabrication processes, nonpotable applications in manufacturing processes as well as air-con cooling towers in commercial buildings. This has freed up a large amount of drinking water,” say PUB officials. The treated water has been put through several tests and its quality is better than what’s prescribed by WHO for potable water.
Treatment of the waste water involves a three-stage process, starting with microfiltration, moving to reverse osmosis and ending with ultraviolet rays. In Delhi, a water reclamation plant with a capacity of 40 million gallons per day will be set up at the Coronation Pillar sewage treatment plant. “The STP will supply us with treated effluent which will be put through a secondary level of treatment and then returned to the river about 20 km upstream of Wazirabad for mixing with our raw water supply. We are then looking at two additional treatment processes – aeration and sunlight and then another stage at the water treatment plant,” said a DJB official.
The project will benefit 3-4 million people in Delhi. Under the memorandum of understanding signed between the governments of Delhi and Singapore, the project will operate on a public private partnership model with Temasek Foundation providing Singapore $463,149 for the plant. “The Singapore government will help Delhi Jal Board (DJB) in preparing an initial feasibility report and a detailed project report. The tender for the project will be issued not before the beginning of 2014 but we are hoping that the work will be completed in the next four years,” said a DJB official.