Case Study: Utility-Grade Relays Protect Critical Motors At Denver-Area Wastewater Plant

The Denver-based Metro Wastewater Reclamation District (Metro), the largest wastewater treatment plant between the Mississippi River and West Coast, has some daunting challenges in disposing of solid waste and returning clean water to the community.

Metro's water throughput from its 380- square-mile district is 150 million gallons per day. The water it purifies contributes 90 percent of the South Platte River's annual flow at the point of discharge. Any sustained interruption of reclamation processes could therefore have a devastating impact on this vital natural resource.

Metro not only treats, but also markets the solid wastes removed from the water it collects from 256 miles of interceptor sewers. Anaerobically treated biosolids extracted from the water are used to improve soil and to enrich agricultural lands. Metro facilities produce 74 dry tons of biosolids daily and apply them to 50,000 acres of district-owned land near Deer Trail, Colorado, and on privately owned land in northeastern Colorado.