Dartmouth Engineer - The Magazine of Thayer School of EngineeringDartmouth Engineer - The Magazine of Thayer School of Engineering

Inventions: Reverse Osmosis Applications

By Lee Michaelides

Inventor: Dean Spatz ’66 Th’67

Reverse osmosis (RO) wasn’t invented at Thayer. Eighteenth-century French physicist Jean Antoine Nollet gets the credit for that. However, two centuries after Nollet’s discovery, RO was still not much more than a laboratory phenomenon until a Thayer student project helped create a new multi-million dollar RO industry.

Students Dean Spatz ’66 Th’67, right, and Chris Miller ’66 Th’67 decontaminate water through reverse osmosis.
PURE GENIUS: Students Dean Spatz ’66 Th’67, right, and Chris Miller ’66 Th’67 decontaminate water through reverse osmosis. Photograph from Thayer School Archives.

By way of review, RO is a “process by which a solvent such as water is purified of solutes by being forced through a semipermeable membrane through which the solvent, but not the solutes, may pass,” according to the American Heritage Dictionary.

When Dean Spatz ’66 Th’67 arrived at Dartmouth, commercial applications for reverse osmosis systems were in their infancy. In ES 21: “Introduction to Engineering,” Spatz and Chris Miller ’66 Th’67 were given a jar of brackish water and told to find a way to make it potable. The pair came up with a prototype for an RO purification system. They ramped up their undergraduate project into graduate-level research that eventually led to Spatz winning contracts from the Department of the Interior to develop low-pressure reverse osmosis systems. Spatz also thought up new applications for the emerging technology. Shortly after getting his degree from Thayer, for example, he built a reverse osmosis system for a friend’s maple sugar operation to separate the maple sugar from the sap.

In 1969 Spatz co-founded an RO company, Osmonics, with longtime Thayer Overseer Ralph E. Crump (see “Inventions: Cryosurgical Instruments”). The company had just two employees, Spatz and his wife, Carol, working out of their garage in Minnetonka, Minn. The husband and wife team did everything themselves, from rolling membrane elements to mailing press releases. Their first machine was sold to the Mayo Clinic for kidney dialysis. The second went to a car wash for a rinse water system. From these humble origins, the company grew into a world leader in reverse osmosis filtration. In 2003 General Electric bought Osmonics for $275 million.

—Lee Michaelides is a contributing editor at Dartmouth Engineer.

For more photos, visit our Research and Innovations set of images on Flickr.

Categories: Inventions

Tags: alumni, curriculum, entrepreneurship, history, innovation, projects, research, students

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