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Sea water for daily chores? NITI Aayog proposes desalination plants to ease country's water woes

The desalination plants will be floating on sea, which will leverage solar energy or ocean energy to reduce their carbon footprint and energy cost.

Sonal Khetarpal   New Delhi     Last Updated: July 15, 2019  | 15:27 IST
Sea water for daily chores? NITI Aayog proposes desalination plants to ease country's water woes

To address the country's water woes, NITI Aayog is reportedly planning to set up desalination plants to leverage India's vast coastline. The proposal talks about setting up plants along the 7,800-km coastline to make sea water potable, which could then be supplied around cities through a network of pipes.

The desalination plants will be floating on sea, which will leverage solar energy or ocean energy to reduce their carbon footprint and energy cost.

The proposal is the result of NITI Aayog's alarming report Composite Water Management Index (CWMI) released last year that predicted that 21 Indian cities, primarily Bengaluru, Chennai, Delhi and Hyderabad, would run out of water by 2020.

However, experts are of the view that desalination will have a limited role in solving India's water woes because it will only address the water problem in coastal cities.

"We need this new technology in coastal cities as water demand far exceeds the natural source of water supply. Also, the cost of desalination has reduced drastically and with renewable energy, the cost of water that comes from desalination plants is much less than what was a decade ago but we cannot use this technology in Delhi as the cost of transport will be high," says Prof Arun Kansal, Dean (Research and Relationships), Department of Regional Water Studies, TERI School of Advanced Studies.

Also, its environmental impact has to be accounted for. "Desalination plants have huge water and energy footprint," says Mahreen Matto, Programme Manager (Water Management), Centre for Science and Environment.  A desalination plant needs an intake of a minimum two times the water output, that is, to generate one litre of fresh water, it needs minimum two litre of seawater. The plant also releases brine (solution of salt in water) in the sea, which destroys underwater eco system, having serious impact on the ecology.

She points out that it's high time to come out of the colonial mindset of fetching water from far off places. "We urgently require a transition from this 'supply-and-supply-more' style of water provisions to measures that improve efficient water use, reduce leakages and recharge/restore local waterbodies. A recovery-based closed loop system is the need of the hour."

Globally, there are 18,426 desalination plants spread across 150 countries, according to the International Desalination Association (IDA), which are benefitting 300 million people. Countries like Singapore are treating their waste water and reusing it for domestic purposes so efficiently that they do not require fresh water anymore. Israel, which is the driest country in the world, leveraged desalination plant to address its fresh water needs. Despite the heavy reliance on desalination, the country has invested heavily in securing their water resources and recycling used water. It also treats 85 per cent of its wastewater, which is used for irrigation, gardening and industrial purposes.

It is important the country starts valuing local resources, rejuvenate and maintain water bodies, as they help in naturally recharging ground water and in controlling floods. What India can do is to introduce a policy to make rainwater harvesting mandatory across states and incentivise those who implement rainwater harvesting structures, she suggests.   

India has 40 days of rain on an average and large chunk of water just runs off. India needs to increase its water storage capacity, says Kansal. "India's water storage is very low and there is a potential to increase it by at least three to five times. This should be done at a decentralised level and through rejuvenating urban water bodies rather than thinking of creating another large dam and reservoir."  

According to Central Water Commission, water storage in reservoirs of most states in west and south India has dipped below the average of last 10 years.

In order to make new approaches sustainable, constant monitoring and maintenance are required. We need strong governance too to ensure we don't fall back to old ways.

Also read: Niti Aayog pushes for Rs 7,500-crore proposal for AI platform, research institutes

Also read: Niti Aayog identifies over 50 CPSE assets for disinvestment

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