Background: The plant was aging and the existing aeration system was old and not well designed. Although the influent load was well below the original design biological loading, the existing aeration system could not keep up. Basin DO levels rarely reached 0.5 mg/l, even when all three available blowers were in operation.
Bioworks’ assistance: Bioworks worked with the city’s engineer, WGK Inc, to determine the optimum
approach and found that it was simple – replace the existing aeration system with the modern Bioworks
system. No additional air was to be needed. The aeration system change-out was done in January, 2018.
In addition to the process limitations of the old system, the plant personnel also reported that working on
the old aeration system was tedious, and were impressed with OXIRISE. So, that option was included.
Results: Once the Bioworks system was installed the basin DO level increased immediately to a level
above 5 mg/l, using the same amount of air that had been used in the past (3 blowers). One blower was
then shut down, reducing the DO level to 3-4 mg/l. Finally, two of the three blowers were shut down,
reducing the basin DO level to the ideal level of 1.5-2 mg/l. Problem solved!