Researchers from MIT's Field and Space Robotics Laboratory (FSRL) have designed a portable, solar-powered desalination system that is cost-effective and easy to assemble to bring drinkable water in disaster zones and remote regions around the globe.

Relief efforts in the aftermath of large-scale natural disasters often call for water as one of the very first priorities: such was the case in the Haiti earthquake back in January. When coping with disasters of this scale the possibility to obtain drinkable water locally, such as by desalination of sea water, dramatically improves the effectiveness of the rescue efforts.

Desalination systems, however, are usually quite large and need a lot of energy to operate; these situations, instead, call for a quick, effective way to turn seawater into drinkable water in loco, with a small and portable system that doesn't need external sources of electrical power to work.

The system developed by MIT researchers does exactly this, and its characteristics make it particularly apt to the task of assisting people in emergency situations. It's designed so it can be cost-effectively assembled from standard parts and put into operation within hours even without the need of technicians. Its specifics mean the apparatus could also found use in remote areas where supplying energy and clean water can be logistically complex, such as desert locations or small villages in developing countries.

Portable desalination

Photovoltaic panels power high-pressure pumps that push seawater through a filtering membrane. Unlike conventional solar-powered desalination systems that run on battery power when direct sunlight is not available, this system can operate efficiently even in cloudy conditions. Algorithms in the system's computer can change variables such as the power of the pump or the position of the valves to maximize water output in response to changing weather and current water demand.

As a result, the prototype can yield as many as 80 gallons of water a day in a variety of weather conditions while a larger version of the unit, which would only cost about US$8,000 to construct, could provide about 1,000 gallons of water per day. Because of its reduced dimensions, the team estimated that one C-130 cargo airplane could transport two dozen desalination units, enough to provide water for 10,000 people.

The researchers are now working on improving the system's efficiency even further and to change its design to make it more durable. The research was funded by MIT's Center for Clean Water and Clean Energy and the King Fahd University of Petroleum and Minerals.