Troy Alabama’s Wastewater Treatment Plant was faced with broken discs causing dropping dissolved oxygen (DO) levels in their oxidation ditch. The 3.5 mgd plant opened in 1979. In 1992-1993, a disc rotor system was installed. After 23 years of service, the discs started breaking. Dave Fiveash, Troy’s Plant Manager for the past 21 years, was driven to find a solution to keep the plant operating and meeting DO requirements.