It's no secret that hundreds of millions of people around the world have little or no access to drinkable water. While a number of projects are aimed at getting filtration systems to those people, many of those systems require electricity, contain costly materials such as silver, or treat the water at a slow rate. The low-cost DrinkPure filter, by contrast, is simply screwed onto the top of an existing bottle, and can purify approximately one liter (34 fl oz) of water per minute.
DrinkPure was conceived by Jeremy Nussbaumer, a student at the ETH Zurich research institute. Working with a team led by ETH's Wendelin Stark, he's created a prototype which weighs just 100 grams (3.5 oz) and that can reportedly meet the hydration needs of one person for up to a year, before needing its filtration media replaced.

Users simply fill a regular plastic bottle with untreated water, screw the filter onto the neck of that bottle, and then squeeze the bottle to force the water through. Filtration is carried out via a three-step process.
A pre-filter starts by capturing large particles such as sand and plant matter. The water then passes through a layer of activated charcoal, that helps remove odors and chemical contaminants. Finally, a proprietary polymer membrane removes bacteria. This polymer was previously developed by two other students, and contains tiny pores that allow water molecules to pass through, while blocking the passage of microbes.
Additionally, the filter as a whole is said to be less expensive and easier to manufacture than most conventional filters.
While commercial availability of DrinkPure for people such as hikers is a possibility down the road, Nussbaumer first and foremost wants to see it used in humanitarian aid. To that end, he has recently launched an Indiegogo campaign, to fund field testing of the device in Africa. A pledge of US$89 will get you a filter of your own, assuming the funding goal is met.
The DrinkPure can be seen in use, in the following video.
Sources: ETH Zurich, Indiegogo