The wastewater treatment plant is located directly east of Ulysses' Temple. After detonating the warhead near the water pipe, it can be reached by traveling along the top of the ruined building lying on its side. A rocky path continues past the building, which leads to the plant. Access is gained via a sewer grate. There is also a warhead left of the entrance which, when detonated, will have 2 lead-lined metal boxes underneath.
Once inside, tunnelers fighting several marked men will appear. Continuing into a room with two guards, a manager's terminal with an entry for the Nostalgia challenge, and a RALPHIE for the Feel Like a Kid Again challenge can be found.
- Pugilism Illustrated - In the interior office, behind the lockers.
- Two NCR Ranger action reports - Northeast of the entrance to the treatment plant and down a ledge. One of the reports is labeled 'Addendum'. Both of the reports are part of the Nostalgia challenge.