The D'Angelo Sewage Treatment Plant is a sewage treatment plant located on Arkham Island in Gotham City.
Owned and operated by the Gotham City Organized Crime Family, the plant is the largest processing plant of its type on the entire eastern seaboard.
During the take over of Arkham Asylum, Scarecrow's men have captured and bound the asylum's doctors and hold them hostage at the treatment plant; planting bombs and explosives around the facility as part of an unknown plan.
- The treatment plant is named after the Angelo Family of the Sicilian Mafia. The family stood as the most powerful of the Sicilian Mob families in Gotham following the execution of the Bertinelli Family until the family's head, Nino Angelo, got too ambitious and was assassinated.