Every last drop: technologies that save water on show
By Ben Coxworth
September 13, 2010
The Fraunhofer research organization is concerned about the world’s fresh water supply. According to the statistics put forth by groups like the World Commission on Water for the 21st Century, that concern is justified – over 450 million people worldwide currently face severe water shortages, and as much as two thirds of the world’s population could be “water-stressed” by 2025. Likewise, a study by the UN has predicted that water is due to become more strategically important than petroleum; in other words, wars could be fought over it. In reaction to scenarios such as these, 14 of Franhofer’s research divisions have joined together to form the Fraunhofer Alliance SysWasser, with the aim of developing sustainable water system technologies. The group will be presenting six of these technologies at this week’s IFAT/Entsorga water trade fair in Munich. Here’s a quick look at each one.
Obtaining drinking water from humidity in the air
There’s already talk of harvesting electricity from the air, so why not water, too? Fraunhofer has developed a system in which a humidity-absorbing brine (salt water) solution runs down the surface of a tower-shaped structure. That brine is then pumped via a natural vacuum effect into a tank where it is heated by solar collectors, causing the absorbed humidity to evaporate out and condense in an area where it can be collected. The system is energy self-sufficient, so it could be set up in regions where there is no electrical infrastructure.
Managing drinking water systems by computer
Using HydroDyn, its water management program, Fraunhofer says that municipalities could identify and locate leaks in their water systems. The system creates a computer model of an existing water system, and compares the output figures of that idealized system with the real figures. HydroDyn is reportedly already in use in Mongolia, Libya, Saudi Arabia and several German cities.
A system like HydroDyn might tell you the approximate location of a leak, but intelligent probes that physically inspect lines from the inside will actually show it to you. Another option for pinpointing leaks is to use long-range ultrasound waves.
Cleaning sewage water with diamonds
Fraunhofer has demonstrated that when diamond-coated electrodes are placed in the water, hydroxyl radicals will form on them and proceed to oxidize all water-borne substances containing carbon. According to the research group, this means that everything from solvents to bacteria to pesticides will be neutralized, leaving behind only harmless salts and carbon dioxide.
More cost-effective disposal
When industries generate highly-polluted water, they have to pay to get it properly disposed of as hazardous waste. Needless to say, many such industries decide it would be cheaper just to sneak it into the closest river or ocean. In an effort to keep disposal fees down, Fraunhofer has devised a “low-cost” modular vacuum evaporation process, which concentrates more pollutants in less water – companies are still getting rid of the same amount of nasty stuff, but aren’t paying for the disposal of all the water that previously would have accompanied it.
Increased yields of biogas from sewage sludge
Fraunhofer has developed a system for decreasing the volume and mass of sludge, wherein it’s treated with ultrasound and then mechanically disintegrated. The process results in more biogas production, and less solid waste. A number of sewage treatment plants are already using this technology.
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