Maintenance of the 33-year-old bar screens at the Kalamazoo (Mich.) Water Reclamation Plant was stressing the operators. Shear pin failures occurred often, and almost always on weekends. The worn and corroded mild steel frames allowed chain guides to wobble, requiring constant chain tension adjustments. When some 1-inch screen rack bars broke, they weren’t replaced because of their difficult location and the unit’s age. Operators worried that rags slipping through the larger gaps would clog pumps and flood lift stations... Read more