The City's Water Pollution Control Plant staff provides the day-to-day operation of the plant, six lift stations, and is responsible for the maintenance of the collection systems. Plant staff is also responsible for the maintenance of the storm sewer collection system. The wastewater plant is located at 3976 20th Street.
The City of Grinnell Water Pollution Control Plant consists of a rotary trickling filter plant with separate sludge digestion. Treatment units include mechanical bar screens, grit removal, two circular primary clarifiers, a single rotary trickling filter, two circular final clarifiers, a single anaerobic digester, a 0.75-million-gallon sludge storage tank, and a three-cell stormwater equalization basin with a 16-million-gallon capacity.