Like many inventors, Bob Nepper, 82, is a compulsive improver. Nepper, an electrical engineer who lives in North St. Paul, Minnesota, has pet projects that have included a self-guided lawn mower and an outside faucet that can run hot and cold. His basement is stocked with tools like a lathe and a milling machine to craft his ideas.
But Nepper, who retired from 3M Company decades ago, is most obsessed with building a low-cost way to purify water in the world’s poorest countries.
Image: Angela Jimenez / New York Times News Service - Bob Nepper, an electrical engineer who retired from 3M Company decades ago, is working on a low-cost way to purify water in the world’s poorest countr
