I can make a claim that few others can, or would admit to. I have been to Green Bay Wisconsin. Not just to the city, or to Lambeau Field, or to one of the many breweries or eateries or wineries in the vicinity. No, I have been to the Green Bay Sewage Treatment Plant, more properly known as the Green Bay Metropolitan Sewerage District. What's shown here is one of the primary clarifiers, I believe, that I photographed on a tour in 1979. The US EPA gave money to local jurisdictions to construct wastewater treatment plants. My job was to make sure that's where the money went. Fascinating.
Here are links to the GBMSD site:
Water Quality Exhibit
Pump Station Photo
Primary Clarifier #1