Recycling waste water to boost supply (Times of India 07 July 2012)

SINGAPORE/NEW DELHI: At the World Cities Summit that concluded this week in Singapore, after discussing over four days integrated urban solutions for liveable and sustainable cities, the delegates from 104 countries and regions didn't have to look far for a model. This city state with an area of only 710 sq km and a total population of just about 5 million has in a way become the world leader in harnessing, successfully, new technologies to deal with scant natural resources in a way that strikes a balance between its economic growth and environment.
In recycling its water and waste (to generate energy), collecting every drop of rainwater and channeling it to its 17 reservoirs, carving out wide urban public spaces as the city develops, reclaiming land from the sea, aggressive greening of surroundings and buildings, building a mass rapid transit system, capping the number of cars on the road and keeping pollution at bay, Singapore has shown its 'can do' spirit which is now inspiring other cities.
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 was available for consumption by the participants at the summit. This 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 high-grade quality, most of the NEWater is used for wafer fabrication processes, non-potable 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.