New tiny water filter that attaches to any bottle

Scientists have developed a light-weight tiny water filter that can be fitted on to virtually any plastic bottle to provide instant clean drinking water.
"What makes our DrinkPure filter unique is that you can screw it on to virtually any plastic bottle. It doesn't require a pump or a reservoir, so it's very easy to use," said Jeremy Nussbaumer student at ETH Zurich.
"You simply screw the filter onto a bottle containing polluted water, then you can put it straight in your mouth and take a drink," said Nussbaumer.
Weighing less than 100 grammes, DrinkPure is considerably lighter than most other filters, and the flow pressure is so high that you can purify as much as a litre of water in a minute just by squeezing the bottle with your hand.

Another benefit is that the unit is less expensive and easier to manufacture than most conventional filters. These qualities, said Nussbaumer, make the filter ideal for development aid projects.
Three filtering stages make DrinkPure one of the most reliable devices currently on the market, researchers claim.

First, a pre-filter captures large particles such as sand and plant fragments; the second stage consists of an activated charcoal powder that primarily removes undesirable odours and chemical contaminants; the third and most important part of the filter is a polymer membrane that removes bacteria.
In fact, this membrane does its job more reliably than virtually any other water filter intended for outdoor use, researchers claim.

Two ETH doctoral students developed this polymer membrane and patented it three years ago. It is based on a new manufacturing process that shows great potential.