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An Alternative for Membranes in Water Purification
PARC researchers have developed an alternative for purifying water that uses less energy than reverse osmosis membrane systems. This new method involves pumping the water in a spiral tube connector, with small branches that lead off. Particles of contaminate being larger than water molecules tend to be forced to the outside walls of the tubing, where they can be diverted away.
.."The purifier requires a constant flow rate of water so that the movements of the particles conform to predicted patterns. That flow of water can be achieved with a low power pump that can be driven by a panel of solar cells."
ed.z.: Nifty idea..but....but..delicate and expensive and just complicated. I think plain old gravity works pretty good for a power source as well. I think we are seeing here a a brain and perhaps culture bias disconnect with developed versus developing world mindset/solution to a problem. I am in the middle there by choice so it really stands out to me. In the developed world, everything has to be done with a complicated and expensive machine. First, learn to melt out iron ore and smelt it, then make steel and develop forging, then design a bulldozer and an infernal combustion engine and some fuels etc to go move that pule of dirt over there. Joe developing world dude still thinks in terms of economical to him and practical muscle power-they'd just grab the next 20 guys and give them baskets and the pile of dirt would be moved in no time at all. Same with these filters. Biochemical energy-lunch- to move 10 gallons uphill a few feet isn't bad at all, whereas solar panels are expensive (a single big panel and a charge controller and a battery are maybe one year's pay to some poor guys on this planet, now ad in the cost of this new device) and if that was all the local juice I had, I'd rather it was going into a truck battery so I could hang out around the old hut at night and maybe have a light so the chidrens could be reading their school work and maybe run a radio and be recharging the cheap connection to the outside world cellphone. Could do all that with a single PV panel, as long as it wasn't running the water contraption all day long..
We have a variety of good ceramic and charcoal and sand filters now that used in series and in conjunction with each other and cheaply can do 99.99% of the filtration needed to remove most of the stuff, and good old sunlight can do the rest shining on the water for a spell direct UV or even a little solar thermal action to heat it up for a while using a reflector oven thing. Water goes in at the top of a column, drips down, comes out pretty clean. Simple. Developing world guys understand "river water goes in top, drink from bottom" in (what can be) a cheap and mostly hand made from local materials device. Sand is easy to find, charcoal is easy to make, and baked clay ceramics have been used for thousands of years. Put those three together you have an indigenous filtration system that can be manufactured most anyplace for much less cash,. or even zero cash, pure sweat equity and some scrounged containers. Now, for maybe making some homebrew *fuel*, the spin contraption might be pretty useful in making your brew a little higher test.