Cincinnati’s Experience with Maximizing Aeration System Energy Efficiency at Three WWTPs

The Metropolitan Sewer District of Greater Cincinnati (MSDGC) made or is currently making upgrades to the secondary aeration systems of its three largest wastewater treatment plants (WWTPs). Aeration systems are a large source of energy usage in wastewater plants so in addition to maintenance concerns with aging equipment, the principle reason for the upgrade is energy efficiency. The aeration blowers were replaced or are currently being replaced at all three plants and course bubble diffusers were replaced with fine bubble diffusers at one plant. All three plants are receiving new aeration control systems to operate as efficiently as possible based on dissolved oxygen demand. The new systems at all three plants are reviewed. Energy usage data comparing before and after the upgrades at the two plants where upgrades are complete are presented. Lessons learned for secondary aeration system upgrades and blower selection are presented for all three plants.