Capital may soon have to recycle waste-water

With no new source of water being envisaged and planned in the near future, residents of the Capital would soon have to `recycle’ waste-water for even meeting their basic daily requirements.

Officials working on the Chief Minister’s dream of providing drinking water “round the clock” to the residents of the Capital by the year 2020, claimed that as of now its realisation seemed “next to impossible” even if one took into account availability of raw water from all potential sources, reduction in transmission loss, water conservation and harvesting the ground water aquifer system of the Yamuna river.

In fact, the National Capital Region Planning Board (NCRPB) in its Regional Plan-2021 has forecasted that to bridge the huge gap between the demand and supply, the Delhi Jal Board (DJB) would have no other option, but to supply `recycled’ wastewater to meet at least 50 per cent of the requirement of the Capital in the year 2021.

For the projected population of 220 lakhs in 2021, the Capital would require at least 5,700 million litres of water per day (MLD), considering that the transmission loss comes down to 50 per cent from the existing 50 per cent. As against the Delhi Master Plan-2001 norm of 363 litres per person per day, NCRPB’s calculations are based on just 225 litres which is the existing availability of water.

Against this requirement, the total availability of water in 2021 would not be more than 3,800 MLD. This includes 200 MLD sub-surface water which can be made available from Yamuna flood plains after protecting it and ground water recharge in Delhi, 370 MLD from sub-surface water, 635 MLD from Tehri Dam and 2,135 MLD from the traditional sources of fresh water. “This would result in a shortage of 1,900 MLD and this has to be met by recycling waste water for non-potable use,” the official said.

Referring to the NCRPB’s draft Regional Plan-2021, the DJB official recommended that all new developed areas should have two lines, one for drinking water and other for non-drinking purposes. All waste requirement for non-drinking purposes in hotels, industrial units, air-conditioning plants, irrigation of parks and green areas and other non-potable demands should be met through treated recycled wastewater, the official said.

“In such a scenario, we cannot be expected to provide water supply round the clock. As of now this seems to be a distant dream, though the DJB has commissioned a pilot study to see if water could be supplied for 24 hours and seven days a week,” the official said. As regards ground water, officials said it was depleting at a very fast pace and quality was also deteriorating because of over exploitation and contamination. “Historical water bodies and ponds are being neglected and encroached upon. There has been no effort to augment all the sources of drinking water,” they said.

Among the long-term solution recommended for Delhi include construction of upstream reservoir to excess drinking water during monsoon for use in lean period and inter-basin transfer of water and construction of Tehri-type multi-purpose projects in the upstream Himalayan foothills.