Greater Bayfield Wastewater Treatment Project

Welcome to the Greater Bayfield Wastewater Treatment Plant In Bayfield, Wisconsin!

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An "Above and Beyond" Demonstration Plant

Stewardship of Lake Superior is a high priority to the City and the PBSD, who enjoy its recreational and tourism benefits throughout the year. To protect this resource, the new GBWWTP applies technologies that provide wastewater treatment “above and beyond” what would normally be required. The Great Lakes Protection Fund (GLPF) and the Wisconsin Department of Natural Resources (DNR) have identified the GBWWTP as a “Demonstration Plant” that showcases environmentally friendly technologies. The GBWWTP also has many energy saving features such as high efficiency motors, lights, aeration, and UV disinfection. The GBWWTP has been online since January 2006, and it has consistently achieved its treatment goals, even at startup.

Project Funding

Approximately 70 percent of project costs were covered through grants from the Wisconsin DNR, the Great Lakes Protection Fund, and the US Army Corps of Engineers. Approximately 21 percent of the project was financed by zero-interest loans and 9 percent through low-interest loans through the DNR. These loans will be repaid over a 20 year period through revenue collected by the City and PBSD.

Greater Bayfield Commission and Municipal Officers and Primary Team Members

Description of the Greater Bayfield Wastewater Treatment Plant (GBWWTP)

Wastewater Treatment

Influent Pumping provides conveyance of wastewater to the plant. Wastewater from the City is pumped from the former City WWTP site to the GBWWTP through a 9,000 foot long 12-inch force main along Highway 13. Wastewater from Pikes Bay Sanitary District (PBSD) is pumped from their intermediate lift station through a 2,000 foot long 4-inch force main.

Hauled Waste Receiving provides wastewater treatment service for customers who have holding tanks and septic systems. During summer months, it is expected that approximately 200 hauled loads of 2,000 gallons each will be treated.

Preliminary Treatment provides fine 1/8-inch screening, which removes a significant amount of inorganic debris. Screenings are washed, pressed, and bagged for removal.

Biological Phosphorus Removal (BPR) occurs when the wastewater is mixed with return activated sludge (RAS) from the Final Clarifiers (described below) and enters a series of three tanks upstream of the oxidation ditches. By depriving the wastewater of oxygen at this stage, microorganisms in the activated sludge consume phosphorus.

Oxidation Ditches provide mixed zones for aeration, which stabilizes the waste, and mixed zones for “anoxic” (non-aerated) treatment, which removes nitrogen.

: Final Clarifiers allow the solids to settle out of the wastewater.
: Cloth Disk Filtration allows the clarified wastewater to be further polished, which allows the plant to meet its monthly average goals of 5 mg/L BOD and TSS.
: Ultraviolet Disinfection disables pathogens prior to discharge to Lake Superior.

Sludge Management

The majority of settled sludge from the Final Clarifiers is returned to the Oxidation Ditches as “RAS.” To keep the solids in balance in the activated sludge system, a portion of the sludge is “wasted” to the Aerobic Digesters, which provide oxygen and mixing for further stabilization of the solids. The stabilized solids are then discharged to the Biosolids Reed Beds, where natural transpiration through the reeds allows the solids to dry in an energy efficient manner. This method of sludge management and storage provides for approximately 7 years of sludge storage.

Schematic courtesy of Jane Carlson of Strand Associates, Inc.