Delafield-Hartland Wastewater Treatment Facility, Delafield, Wisconsin

New effluent limits requiring phosphorus removal and lower BOD concentrations forced changes to be made to the existing 20 year old wastewater facility. Rapid growth in the area and a new sanitary district connection brought the existing flow close to plant capacity. Foth provided engineering services from the facilities planning phase through design and construction.

Challenges:

A major challenge to this project required changing treatment process from rotating biological contractors (RBC's) to activated sludge. The change required the RBC's be maintained for treatment usage while the activated sludge process was being built. Once a portion of the activated sludge process was operational, the RBCs were demolished and the remainder of the activated sludge process was completed.

Another challenge to this project was converting the existing two-stage conventional anaerobic digesters to a temperature phased anaerobic digestion (TPAD) designed to meet Class A criteria. Improved heating capacity, sludge mixing, and an innovative operating system allowed the existing digesters to be converted to a TPAD process.

Project Specifics:
Average flow.......................................3,260,000 gpd
BOD....................................................5,538lbs /day

Benefits:

• The Delafield-Hartland Water Pollution Control Commission received a significant upgrade to their facility at an affordable price.
• The project design offers flexibility and energy efficiency. The site plan allows for further expansion up to build-out conditions for the sewer service area.
• The Class A sludge provides worker and user safety while expanding the alternatives for ultimate sludge disposal.
• Hydraulic improvements to the primary and final clarifiers have resulted in higher solids removal efficiency.
• The equipment procurement process benefited the Owner with competitive bids on the best equipment for their application.
• Worked with the Commission on obtaining approvals from the City of Delafield and obtaining project financing.