Silver Filter… The Answer to Polluted Drinking Water?
Photo: Sean Rogers
Water may very well just be the most precious resource on the planet, and over 1 billion of the world’s inhabitants lack it. In most cases it’s not even the absence of water, but the inability to access clean water. Resulting disease from bacteria kills millions of children annually, and stunts the growth of millions more. Yi Cui of Stanford University thinks he may have discovered a solution.
The advance lies in the technology of water filters. Traditional filters worked simply by forcing water through pores to extract bacteria. A downside to this process is that it requires a lot of power to constantly change out bug infested filters. Dr. Cui’s filter doesn’t merely sort out the bacteria; it kills them.
The filter is comprised of carbon nanotubes and silver wires laid across a thin strip of cotton. Silver has a reputation for killin’ bugs, and is a good conductor of the electrical current that Dr. Cui’s runs through it to make the process more efficient still.
When operated at -20 volts the apparatus killed 89% of bacteria, 77% at +20 volts (whatever that means). Notably however, at 0 volts most of the bacteria survived, meaning this thing needs to be juiced to be effective. Good news! The amount of (expensive) silver and electricity needed is minute. AND, in an experiment where contaminated water was run through 3 filters 98% of bacteria was eliminated, AND the filter is supposed to last indefinitely. An advance that could potentially have great impact on the basic needs of so many.
Find more in the October 23rd-29th edition of The Economist
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This sounds seriously awesome!
Our global inventory of water is limited and finite. the only difference of having water and not is where the water accumulates nad is disperesed from the atmospheric cycles.The filtering of existing water in some areas would be an awsome accomplishment,but further decontamination along with education in these areas would have to be included in the larger picture. The people in most of these areas of need are the main polluters of their own supply.The additional benefit of this type of bacteria killing system would be also a needed enhancement to desalination of ocean water for agricultural applications,people and animals can consume water in plant form grown close to the water source.this would add water to the global inventory and reduce energy consumption for transportation and storage facility construction.