Fresnel Water Purifier: A new method of water decontamination using a Fresnel lens

The World Health Organization estimates 750 million people lack clean, drinkable water, 82% of those in rural areas.  Every day 2,000 people die because of it. The Fresnel water purifier is a new design to produce drinkable water and help stop these deaths.  Fresnel lenses are inexpensive, flexible lenses that were used in rear projector televisions.  They can achieve temperatures in excess of 2000F at their focus.  Using a Fresnel lens, sunlight is directed onto a copper coil filled with water. Only when temperatures are high enough to kill disease producing, biologically active agents does a thermostat at the coil’s end open allowing water to flow.

The system is made using a salvaged Fresnel lens, a car thermostat and locally available materials for the frame.  It costs $30-70 depending on design, has an estimated life span of at least five years, and requires very little maintenance or training to operate.  Proof of concept testing in Virginia, USA, demonstrated its ability to reduce the coliform level of contaminated water to zero per 100ml.   Funded by crowd sourcing, follow on testing in the Republic of Panama demonstrated it can produce 15L/day of drinkable water.  In collaboration with the Universidad Autonoma de Chiriqui (UNACHI) in David, Panama, further testing is underway to demonstrate its effectiveness and to experiment with designs that may not only heat the water but also distill it.  Field testing is then planned in areas of poor water quality to assess if its use decreases diarrheal diseases and other illnesses.