Pamela Wolfe
Innovation is finally driving desalination costs downwards to affordable levels at a time when the demand for clean drinking water in Asia, Europe, the Middle East and the Americas is rising rapidly. Water scarcity problems in growing urban centres located in arid, coastal regions are not the only reasons why municipalities are investing in desalination and membrane plants; contaminated water supplies in inland areas also account for this growth in investment.
According to the latest "Reverse Osmosis, Ultrafiltration and Microfiltration: World Markets," published by McIlvaine Company, "orders for membrane desalination equipment will reach US$ 1.8 billion annually by 2007, which is driving the total cross flow membrane equipment market worldwide to more than US$ 8 billion in 2007."
Once mostly limited to oil-rich Middle East nations that could invest millions in costly desalination plants, the technology is now considered affordable given advances in technology and design that have increased water production rates and decreased energy costs. Large-scale desalination can now produce water as low as US$ .50 per cubic metre of water.
Hybrid plant designs enhance the advantages of reverse osmosis, multiple-effect and multi-stage flash technologies and minimise their disadvantages. Integrated power and desalination plants save energy costs by using waste heat generated in the on-site power plant. Desalination costs could fall much farther by developing low-cost, alternative technologies that depend on renewable energy resources to power up small plants in countries scarce in drinking water and infrastructure funding. And a new innovation, the Rapid Spray Evaporation™ from the US company AquaSonics, promises to further reduce seawater desalination costs by at least 50%, eliminate brine and create dry salt as a by-product (page 28).
In India, desalination is now considered an indispensable option given the limited resources available to increase water supply in the city of Chennai, where the Tamil Nadu government is speeding up a desalination project to solve a long-run water shortage situation. This water supply alternative, government officials contend, could prove a valuable source to bridge the gap in supply that arises from insufficient inflows to conventional systems – either the local sources or from inter-state sharing networks. This US$ 331-million desalination project signals a shift in water management policy that previously considered only rainwater harvesting and wastewater recycling as alternative water supply solutions in addition to traditional sources.
Even in the United Kingdom, plans are reportedly underway to construct a desalination plant in east London and six new reservoirs in response to rising water demands and dwindling supplies, according to the Independent newspaper on 26 October.
In the US state of California, 20 new desalination plants are in some phase of development in addition to 12 small desalination plants that have been operating along the Pacific coast, according to the McIlvaine report (www.mcilvainecompany.com). The report explained that the this surge in activity is being driven by "the continuing reduction in the operating cost of RO systems," while the cost of procuring and treating surface water has continued to rise.
China is investing heavily in its water and wastewater treatment infrastructure to improve the poor quality of its rivers, lakes and stream from which it draws its water supplies. In the meantime, consumers are increasingly turning to bottled water, which is produced by reverse osmosis plants.
In the Middle East, which depends on desalinated water for drinking water and irrigation for much of its water supply, more than US$ 100 billion is projected to be invested in power and water desalination projects within the next decade. Here, the private sector will play a major role in financing these projects because governments in the region can no longer afford the massive investment without help from the private sector. For example, the total project cost of the Umm Al Nar power and water project in Abu Dhabi reached US$ 2.1 billion; this type of investment rivals only those in the oil and gas industry. The United Arab Emirates, the second biggest desalination market in the world after Saudi Arabia, will have a major share in this market.
Pamela L. Wolfe, Managing Editor
