The Water Challange - Why Desalination Technology Deserves your Vote

Today, the supply of fresh water presents one of the most pressing challenges ever faced by the human race. It is a vital resource for human life. Yet, population growth and enhanced living standards, together with the expansion of industrial and agricultural activities, are creating unprecedented demands on clean water supplies all over the world. The Organization for Economic Co-operation and Development (OECD) and the United Nations (UN) have reported that 0.35 billion people in 25 different countries are currently suffering from water shortage, and this will grow to 4 billion people (two-thirds of the world population) in 52 countries by 2025. In addition, a staggering 2.6 billion people have no access to proper sanitation. .

When you consider the facts from the World Health Organization (WHO) and other agencies, the root cause of this mounting crisis becomes clear.  The world's population tripled in the 20th century, and is expected to increase by another 40-50 percent in the next 50 years. The unavoidable fact is that there is no more fresh water in the world today than there was 1 million years ago, and water as a resource cannot be replaced in the way that alternative fuel sources can replace petroleum.

Areas affected by acute water shortage are often in the poorest, most underdeveloped countries, which lack the necessary power and water-delivery infrastructures. The lack of clean water also creates considerable health, energy and economic challenges to the populations of these countries. Because of a growing population and climate change,  water shortages will eventually limit economic growth and food supplies.  The provision of clean water therefore represents one of the most pressing challenges of the 21st century.

What are the sustainable solutions to this challenge? What are the priorities? More and more reservoirs, wells, pipelines and river transfers are not the answer. Yet,  in arid countries around the world, where conventional water resources are scarce, impaired-quality (non-conventional) water sources are still available for exploitation, such as seawater, brackish water, wastewater (and various effluents) and stormwater runoff.  In particular, desalination of sea water has increasingly proved itself to be the most practical - and in many cases the only possible - solution for many countries around the globe, and particularly for the Arab World.

Today, a new generation of lower energy and sustainable technologies are needed urgently for the desalination of sea and brackish ground water, waste-water treatment, and recycle. Indeed, for many water stressed regions around the globe, tapping into the seas may be the only option available to address the gap in fresh water supply for the foreseeable future and meet the increased water demand due to population growth, expanding urbanization and industry.

The rapid development of water desalination technologies and its market in the last decade clearly reflects their growing importance. However, in spite of the significant technological advances and successes in reducing energy requirements (mainly in membrane-based processes), desalination remains an energy-intensive process, contributing to greenhouse gas (GHG) emissions and thus having a contributory effect on climate change. In some GCC/MENA (Gulf Cooperation Council/Middle East-North Africa), countries, the situation is especially challenging in terms of the cost of energy use, because thermal-based processes such as multi-stage flash (MSF) and multi-effect distillation (MED) dominate the market; these processes depend directly on the availability and cost of fossil fuel. Furthermore, they rely on the availability of good prior experience gained in these technologies, and must often deal with challenging seawater quality, especially in the Gulf region. To meet these and other related challenges, there is currently a tremendous interest in identifying breakthrough solutions that address these global problems of water security and sustainability of water resources at a lower-cost, while also being more environmentally friendly.

To be clear, our objectives should be to target a reduction in the specific energy consumption of seawater desalination to reach 2 kWh/m³ in the near-term, and to develop more sustainable desalination processes which are less dependent on conventional energy sources and more environmentally friendly in the longer term.  This will be enabled by exploring the development of new and emerging low-energy and renewable energy-driven desalination technologies. Research towards this should focus on the hybridisation of forward osmosis (FO), membrane distillation (MD), and adsorption desalination (AD), coupled with or standing alone from  conventional desalination processes such as MED and reverse osmosis (RO). In particular, both nanotechnology and membrane processes are set to play a key role as enabling technologies;  global demand for membranes alone is set to  increase by 9% annually, with a forecast of  more than US $20 billion in the water sector by 2015.

There is a clear and urgent need to undertake fundamental research in the water sciences and advance the development of water technologies to deliver innovative solutions that address these global challenges of sustainable and secure water resources. Key research objectives that will have immediate impact globally include to:

• Research and develop novel technologies for water desalination and reuse;

• Optimize and hybridise desalination and reuse technologies for enhanced performance;

• Promote water technologies for sustainable urban, agricultural and industrial applications;

• Research urban and natural hydrologic systems to enable improved water resource understanding and management;

• Disseminate knowledge through demonstration, engagement and technology transfer.

Water security is the biggest challenge we face on the planet. The Longitude Prize 2014 can be the catalyst that helps us to do something about it. We must act urgently and move ahead, if these technologies are to be available and deliver the needed solutions in time.

This editorial was written by Professor Nidal Hilal, from CWATER.

You can vote to make ‘water’ the challenge for Longitude Prize 2014 at www.bbc.co.uk/horizon and read more about the prize at www.longitudeprize.org