Public Work Utilities Division technician David Bodway with “Cousin It,” one of two submersible pumps at a City of Peoria, Ariz., wet well. The pump station’s average flow is about 1.1 mgd; peak, 1.8 mgd.
Unlike a high-speed, low-torque chopper pump, a sewage grinder is a low-speed, high-torque piece of equipment. A 29:1 gear reducer enables this 10-hp JWC Environmental grinder to deliver 45,000 pounds of cutting force. A chopper pump generates roughly one-tenth the force.
After substantial outreach, residents still think it’s OK to flush consumer goods — as Portland Water District employee Tom Hume points out — because packaging isn’t prominently labeled “don’t flush.” To identify and quantify what’s clogging pumps, use the Maine Wastewater Control Association’s Pump Clog Standard Operating Procedure at http://go.hw.net/PWpumpclogs.
A chopper pump slices debris as it pumps sewage. This takes more electricity but requires less maintenance vis-à-vis clogs.