Staff: wastewater plant upgrades caused temporary emissions rise; full benefits expected by 2030

Committee members queried staff about a roughly 9% increase in plant‑level emissions reported in the draft inventory. A member noted the staff report’s language and asked whether the increase reflected higher effluent emissions tied to aeration basin work. Plant staff responded that renovations left three of four basins operating in a hybrid mode and that balancing old and new aeration technology during construction has complicated operations and temporarily raised emissions.

Staff said the schedule anticipates startup of the new system in 2027 and that full benefits — including reductions in nitrous‑oxide emissions — would not materialize until closer to 2030. "According to Plant Staff's calculations, we should see it it's a temporary increase. And once all the work is done, starting in 2027, it should go back down to normal levels," Watts said. Committee members requested clearer language in the staff report to explain the temporary nature and the timeline for recovery.

Staff offered to provide follow‑up details offline, including the specific drivers behind the reported per‑gallon emissions change and any interim mitigation steps the plant can take to limit emissions during construction.

What happens next: staff will provide follow‑up material on the wastewater plant emissions in an upcoming report and clarify the schedule and expected emission trajectory through 2030.