I saw an ad for this Solar Cube in a magazine recently. It uses solar and wind power to provide drinking water and emergency electricity. The system can purify water from any source and is able to turn up to 1,500 gallons of seawater a day or 3,500 gallons of fresh water a day into drinking water. The cube is powered by 24 volt batteries which are charged by solar panels and a wind generators. The cube is able to clean its own filters and will last, according to the manufacturer, for a minimum of seven years.
PUR® Purifier of Water is a product developed by Proctor and Gamble for sale at no-profit to users and NGOs. It’s pretty cool. The product contains powdered ferrous sulfate (a flocculant) and calcium hypochlorite (a disinfectant). Users add the contents, stir, let the solids settle to the bottom of the bucket, strain the water through a cotton cloth into a second bucket, and wait 20 minutes for the hypochlorite to inactivate the microorganisms.
PUR inactivates viruses, bacteria, and protozoa. In addition, PUR removes arsenic and turbidity (dirt) from water, leaving the water safe to drink. PUR costs around ten cents to treat the drinking water for a family of five for one day, and reduces the incidence of diarrhea in young children by around 50%.