Facing a need to reduce effluent nitrogen and phosphorus, the Kansas city of Great Bend had a choice: Try to get it done with oxidation ditch process adjustments, or invest millions of dollars in a new clean-water plant.
The operations and laboratory team members chose process changes. With the advice of an operations specialist, the addition of a $25,000 variable-frequency drive, some diligent work and a little trial and error, they succeeded.
Effluent total nitrogen has come down from 8 to 12 mg/L to 3 to 6 mg/L on average, and total phosphorus has dropped from about 2 mg/L to 0.5 mg/L
