The Colton WWTP in Colton, CA was upgraded in summer 1998. The primary upgrade was the addition of two reinforced concrete race-track style aeration basins and circular clarifiers.
Three new clarifiers, an oxidation ditch and a sludge pumping station are under construction as part of a $ 6,500,000 project to up-grade an existing sewage treatment plant in the Chicago suburb of Hanover Park.