When Dean Spatz began his introduction-to-engineering-design class as a sophomore at Dartmouth in 1963, reverse osmosis, the process of filtering water through a semipermeable membrane, was only four years old. Working with a team, Spatz used RO to create a prototype for turning undrinkable brackish water into a potable liquid. The commercial applications were obvious, and Spatz dedicated the rest of his time at Dartmouth to developing the nascent technology. After graduating, he founded Osmonics, Inc., one of the first reverse-osmosis companies, in his garage in Minneapolis.
Today reverse osmosis is vital to a wide array of industries. "It's absolutely astounding that it's happened so quickly," Spatz says. By far its most common use is in desalination plants, which convert seawater into drinkable water. Later this year the 250,000-square-foot Carlsbad Desalination Project near San Diego, the biggest plant in the Western Hemisphere, will begin creating roughly 52 million gallons of freshwater per day. At the heart of the plant is RO technology supplied by General Electric, which acquired Spatz's Osmonics for $253 million in 2003—just 40 years after he and his team developed their first prototype.