Dwindling Resources Using Sea Water

 

Over centuries, a lot of work has been done on water, which comes only second to oxygen as the life sustaining substance. While methods of water conservation are well known, we need to further augment the known methods of water management through a holistic approach to the issue of water. This means that we have to look at other sources as well besides the traditional river source. If we can think out of the box we should be able to generate new ideas. Undoubtedly, catchment area treatment & sediment control, reforestation, curbing pollution, preserving bio-diversity, salinity control, protection of water quality, combating global warming, greening of the Himalaya and reversing environmental degradation are many fields where concerted and coordinated action by all those sharing a river basin will be useful, though the focus is more on the River Basins. Rightly so – that will be the largest resource – but it is a traditional approach which needs to be supplemented by bringing in other non conventional sources as well. Unfortunately there are two lobbies in India the pro dam and the anti dam. This prevents people from thinking without prejudices. One believes that water is becoming so scarce that one has to integrate and optimize all systems with ruthlessness and with a broad vision.

Making Sea Water Potable

One area in which more work can be been done is the bulk use of saline land and the ocean water.  Ocean is a largely untapped resource – in fact all the river water is nothing but distilled sea water.   Besides reverse osmosis and the highly energy intensive distillation process no other meaningful research has been done on this subject. Sea water is a vast resource and one remembers raising this issue at a National Conference on Water – a large number of people came forward to say that it was an excellent idea – but most of it was lip service.  My submission is that since we are looking at the next few decades we have to start working towards the future when river water might not be available in prolific quantities or we may have to supplement it with other sources. Since there are only two known methods of Desalination, if, as a national policy, more funding is done on researching alternative use of ocean water from now itself, we might be able to arrive at something tangible a few years down the line.

 

A real game changer, from India’s point of view, is the news that came just two days back, India’s largest desalination plant[1] was inaugurated in Chennai on Saturday the 31st August. The facility will draw water from the Bay of Bengal, process it using the reverse osmosis technology and supply purified water to the city. The joint venture between IVRCL Infrastructures and Project Ltd and Befessa of Spain, spread across 60 acres, has been built at a cost of  Rs 600-crore at Minjur. It can desalinate 100 million litres of water per day, sufficient for around 2 million people. Thus it would cater to half of Chennai’s population of about 4.5 million. What is most interesting is the fact that the plant will supply water to the Chennai Metropolitan Water Supply and Sewerage Board at a cost of just about 5 paise per litre for the first 25 years. The competitive pricing is because the facility adopts an energy-conserving desalination process, According to CMWSSB officials yet another desalination plant with similar capacity is expected to come up in Tamilnadu by 2012. Earlier, in January this year, Saudi Arabia’s national science agency announced a new initiative to build solar-powered desalination plants to reduce water and energy costs by 40 percent. For Saudi Arabia there had been no breakthrough in the cost of desalination. The gradual reduction in cost due to improvement in technology had been mostly offset by increased material and labor cost. The initiative will be carried out in several stages, and the first plant will be a small, 30,000 cubic meter per day facility in Al-Khafji. In comparison, the Shoaiba 3 project onSaudi Arabia’s west coast is the world’s largest plant, producing 880,000 m3/d .During the initiative’s second phase, a 100,000 m3/d plant will be built. Eventually a network of plants across the country.

 

The idea that the sun is delivering per day as much energy as we consume per annum on fossil energy has inspired some scientists to find solar solutions for the global water shortage. Solar distillation units have been extensively studied and deployed on a moderate scale but little effort has been done on scaling them up for greater output. The reasons for this are not difficult to see, the most important one being  the cost. With the world water demand increasing because of rising population and industrialization and with fossil fuel prices spiraling up, it becomes imperative to look at new methods of solar distillation. These systems should be able to have the ruggedness of the fossil fuel fired plants, should be economically attractive, and, above all, should work on renewable sources of energy.

 

Indigenious work in the area in India has been sporadic and has gone largely unrecognized. One such example dates back to 1980, when a paper was published by Nimbkar Agricultural Research Institute on ‘A Scheme For Large Scale Desalination of Sea Water By Solar Energy’. The scheme had been for using solar energy available in abundance in the coastal Desert of India – The Thar Desert. The design was to produce about 5.25 x 10 m3/yr (13860 MG/yr) of fresh water with 11.52 km2 (4.5 miles2) of collector area. Economic analysis of the scheme made at that time showed that it compared favorably with the existing fossil fuel fired desalination plants of the equivalent capacity.

 

One does not know as to what happened to the scheme nor is one suggesting that the same scheme could be implemented today. In fact some more sophisticated systems using solar energy might have been developed. Considering that energy for driving a car is derived from hydrogen extracted from water is some of the newly launched green cars. Something that wasn’t considered possible a few years ago. The major problem is to develop a mindset, in which, we as a country, should be willing to risk investment in R & D for leading edge technologies ahead of the west.  Already resorts and hotels around the world, such as the Hyatt  Regency, Grand Cayman Islands, rely on seawater reverse osmosis systems for potable and irrigation  water direct from the sea for their guests. Off the shelf Sea water desalination systems are commercially available with capacities as high as 6,000 gallons (22,712 litres) per day, though the cost is still high (though not prohibitive) at about $ 40000 (Rs. 18,56,004) for a plant of that capacity.

Countries which research in the leading edge technologies related to environment will be the super power of the future. There is an ongoing research in a few select countries on optimizing the Efficiency of Reverse Osmosis Seawater Desalination. Uri Lachish, guma science has done some study based on van’t Hoff’s theory of the osmotic pressure, for which he received the first Noble prize in chemistry. As recently as 2004, Zonnewater BV, from Netherland , developed a desalination unit based on solar energy (95% thermal and 5% photovoltaic or wind energy), suited for coastal areas with an average temperature of 30 degrees Celsius. However, at lower temperatures, the system will work as well but output will diminish. The founder and only employee of Zonnewater, Mr Jan de Koning a former employee of a chemical multinational started this company in 2002. The goal was to develop a reliable, simple, maintenance-free and optimized drinking water system that needs no regular spare parts (like filters or membranes) and is based entirely on renewable energy. And the Innovation: Aqua Solaris Family Well: one cubic meter of clever physics and technology producing 40 liters of premium drinking water per day for the main needs of one family. The Agri Well requires approximately five square meters of ground cover and 200 liters per day output – the basis for a family, a small drinking water business, irrigating a small vegetable garden, etc. Large-scale systems for solar desalination, wastewater treatment and a simple and reliable technology for drinking water sterilization are in development.

 

Yet another example of  renewable sources of energy for desalination – Tidal Power.  It is the cost advantage Mr Engelsman’s Energetech is capitalising on using its own wave energy machine to power an on-board desalination plant. Fifty per cent of the cost of a litre of water is energy. Conventional desalination plants require huge amounts of energy, meaning the water produced is considerably more expensive than tap water. Under Mr Engelsman’s plan, to harness the power of the ocean, the energy cost is reduced to zero – cutting the price of the desalinated water to 55 cents per cubic metre. That is close to the price of the cheapest water in Sydney, which Mr Engelsman puts at 47 cents per cubic metre. This proves that the ability to make low-cost water is a completely viable option. The scheme also has other benefits – it does not emit greenhouse gases, it does not tie up valuable land and it is easier to dispose of by-products like brine. A Port Kembla prototype is the only one of its kind though the company already envisages clusters along the coast, linked together, feeding water to coastal towns and industries, at a price that makes it hard to say no to desalinated water. At Port Kembla in New South Wales, a turbine designed by Energetech is generating seven kilowatts of power per metre of wave. The design of the wave energy machine is simple: v-shaped arms force the incoming waves into a chamber, pushing air up and down. The air moves past a turbine with rotating blades that act like aeroplane wings, keeping it spinning in one direction and generating energy. In reality it is nothing other than a fan in an airstream.

One doesn’t have to mention so many Indian companies operating in the area of desalination. For example Shivsu Canadian Clear Crystaline Waters (India) Pvt Ltd. has executed 5000 seawater desalination plants worldwide with options of containerized desalination plants as well as on site plants. But they use the conventional sources of energy. Of the more than 7,500 desalination plants in operation worldwide, 60% are located in the Middle East. In contrast, 12% of the world’s capacity is produced in theAmericas, with most of the plants located in the Caribbean and Florida. To date, only a limited number of desalination plants have been built in India, primarily because the cost of desalination is generally higher than the costs of other water supply alternatives available However, as drought conditions occur and concern over water availability increases, desalination projects are bound to find favour.

 

Most of the ground breaking research has been done by individuals who are often not taken seriously. How many of us remember an Indian scientist who claimed to have developed fuel from grain and whom the cynical Indian media joined the International press in ridiculing. Was it vested interests? Now bio fuel is a watch word the world over, but even if one uses the most powerful search engines one will not be able to discover that ingenious gentleman’s name.


[1] Hindustan Times, 1st August , 2010

 

Copyright Manohar Khushalani

 

The author was formerly a Head of Water Resources and Chief General Manager in Scott Wilson and a Jt. Advisor to Central Board of Irrigation and Power. Amongst others he is Consultant to Wapcos, Synergics, PACT, Geoinformatics, InspireOne. He has worked as a Director in design and research wing of Central Water Commission in areas of Dams, Hydraulic Gates, Instrumentation and Environment. He was also a Director at National Water academy, Khadagwasla. He is the co-author of Irrigation Practice and Design(Five Volumes) Published by Oxford & IBH and Sponsored by National Book Trust. He is also running a fortnightly Ezine on Culture (http://www.UnoUniverse.info). He has trained and taught extensively in the same areas as well.

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *