From fish to pipes, Minnesota firms see opportunity in growing water challenge

Business Martin Moylan · ·
Tilapia swim in a tank at Urban Organics, an organic fish and vegetable farm in the old Hamm's Brewery in St. Paul, Wednesday, Apr. 2, 2014. The waste water from the fish tanks provides nutrients to the hydroponically-grown greens and herbs, whose roots purify the water which then goes back into the fish tanks.