Pedal Filter

I really love this idea! Using pedal power (video below) to filter water on your way home from the ol' watering hole is a great idea. It is also, however, limited by a few situations which may or may not apply depending on the location.

Terrain: When I was in the wilds of Lesotho I could barely walk up mountain slopes with a 10 gallon jug of water, let alone pedal up one with a 20 gallon bicycle.

General health of the user: If the person using the device is malnourished or otherwise unhealthy, letting the water boil on teh fire while they conserve bodily energy by not pedaling may seem a more desirable option. All this to say that the bicycle isn't a cure-all solution. Other helps, such as food, education, and medical aid, and political stability need to be implemented in-concert with one another.

Cost of the filter: Firewood in most parts of the world is a free resource, which is why it's open to abuse and is being degraded. For the very poor a water filter would have to be offered at a cost near free. Otherwise the people for whom it is designed will go back to chopping down trees.