The Fredericksburg (Iowa) Wastewater Treatment Plant has faced challenges from change in its industrial flow and from upgrades to aging equipment.A key operating objective has been to limit electricity costs while still providing adequate aeration for treatment. In 2014, as part of a plant upgrade, the city replaced two old centrifugal blowers with a pair of turbo blowers outfitted with variable-frequency drives.The new configuration enables more effective control of dissolved oxygen concentrations in the plant’s three aerated lagoons. It is projected to save $30,000 per year on electricity and has ended an intermittent odor issue caused by low oxygen conditions
