The City of Tonganoxie’s wastewater treatment  facility study was initiated by permit compliance issues and the high rate of development in this bedroom community for Lawrence and Kansas City. BG Consultants’ involvement began with the development of a facility study and recommendations report. All aspects of the existing plant were evaluated for hydraulic and organic loading capacity. Population growth trends were used to assess the life of the current plant and plan for a future expansion to 1.5 MGD.  Through a present worth analysis, BG also compared expansion alternatives, and then made final recommendations for the immediate design and construction of Phase I improvements, which would expand the plant to a capacity of 0.75 MGD.

The plant is an activated sludge extended aeration oxidation ditch design.  In anticipation of future BNR limits, the plant included a pre-aeration anaerobic selector tank and an anoxic tank for achieving a TP of one milligram per liter and TN of eight milligrams per liter. The overall plant design included flexibility for the construction of future phases and also provided space within the process for filtration if TP limits end up being less than one milligram per liter. Sludge is processed with an aerobic digester and belt filter press for disposal at the local landfill. As a cost-saving measure for the project, all major process equipment was pre-purchased.  

Components of the Phase I improvements included:

• Site grading
• Access roads
• Influent pump station
• Headworks building with washer/compacter and automated barscreen
• Vortex grit chamber with grit classifier
• North and South splitter boxes
• Aeration basic
• Two secondary clarifiers
• UV disinfection and building
• Non-potable water pump station
• Cascade
• RAS/WAS pump station and building
• Aerated sludge tank
• Process building with belt filter press sludge room, laboratory, MCC, office, break room, piping, valves, and all other associated appurtenances