At a time of uncertain water supplies, how can we get the most use of our water? By passing water through a material called a reverse osmosis membrane, adding a small amount of hydrogen peroxide and exposing it to ultraviolet light, engineers in Orange County, California have been turning what used to be considered useless wastewater into drinking water for more than 25 years. David Sedlak’s research team at Berkeley has developed technologies to improve the treatment processes. Series: "Cal Future Forum: Our Changing World" [Science] [Show ID: 33071]