Waukesha plant manager reports A ratings on CMAR; board recommends 2024 report to council

Zack Eisner, plant manager at Waukesha's Clean Water Plant, reported June 5 that the city's 2024 Compliance Maintenance Annual Report (CMAR) earned A grades in all 10 categories and that staff will recommend the report to city council.

The CMAR is the Wisconsin Department of Natural Resources' annual review of wastewater-utility performance, covering treatment, biosolids, preventive maintenance, staffing, collection systems and financial management. Eisner told the Board of Public Works the plant has performed well overall, with two small issues in 2024: a roughly 50-gallon overflow and a missed six-month average phosphorus target caused by short, high-concentration spikes in influent.

"My name is Zack Eisner. I'm with the Clean Water Plant," Eisner said during his presentation. "I'm happy to report for the ninth year in a row. We scored an A on all 10 categories." He described the overflow as about "50 gallons" and confirmed a prior missed six-month phosphorus average.

Board members asked several follow-up questions about how common A grades are, the plant's equipment replacement fund and whether biogas purification remains on the plan. When asked what percentage of plants statewide earn A grades, Eisner said, "I'd have to ask the DNR that question. I'm not sure." He explained the required equipment-replacement balance and reserve structure: the plant currently maintains about $3,600,000 in the DNR-required equipment-replacement fund and used about $40,000 in 2024; larger draws are expected for a recently awarded large project.

On future projects, Eisner said much of the long-range work will be financed from clean-water cash reserves and that the $3.6 million balance represents a DNR-required minimum tied to asset value. On biogas purification (project 14 in the plan), Eisner said the city is not proceeding immediately but will reanalyze the option around 2029 if technology or economics change.

Eisner and board members also discussed phosphorus limits by outfall. A board member noted that the Root River standard is 0.06 milligrams per liter; Eisner said the plant generally meets that limit and that occasional "slug loads" in influent can cause short spikes that affect the six-month average.

After discussion, the board voted to accept the 2024 CMAR and to recommend it to city council for formal acceptance.