Delhart general manager reviews plant upgrades, capacity and future regulatory risks

Rob Manema, general manager of the Delhart wastewater commission, told the Village of Hartland board on Tuesday that the facility completed a biological phosphorus upgrade in July 2024 and is operating within its design average but faces regulatory uncertainty on PFAS and potential future nutrient limits. "If we did nothing, the estimated chemical cost to meet limits would be about a half million dollars a year," Manema said, explaining part of the rationale for the roughly $7 million biological upgrade.

Manema said the commission, formed by the City of Delafield and the Village of Hartland in 1971, put the plant online in 1980 and completed a major capacity expansion in 2005. That project increased design flow from 2.2 million gallons per day (MGD) to 3.23 MGD; the facility’s current average flow is about 2.0 MGD and the design peak-day capacity is 6.54 MGD.

The presentation summarized past capital costs: the original 1980 plant and early interceptors, a 2005 expansion (about $16 million), a 2019 UV and disc-filter upgrade (roughly $3.7 million), and the 2024 biological phosphorus project (~$7 million). Manema said the new biological processes — including added anaerobic zones and a fermenter — reduce reliance on chemical dosing to meet phosphorus limits and will provide operational savings over the plant’s life.

Manema described performance and a recent extreme wet-weather event. He said the plant achieved roughly 99% removal of BOD, TSS and ammonia at the time of the presentation and that an August storm produced a peak-day influent flow of 6,114,000 gallons — nearly the peak-day design. "We were almost at our peak day design. We were able to process the wastewater, get it through the plant, but it was pretty challenging," he said.

On future regulatory risks, Manema noted that the EPA has issued guidance on PFAS on the drinking-water side and that wastewater regulation on PFAS remains uncertain. He said there is no widely available treatment that removes PFAS without creating a concentrated residual — which then must be disposed of, likely in landfill. "If they would actually implement something, a knee-jerk reaction would be astronomical," he said, characterizing potential near-term costs as high and long-term action as more likely.

Manema also summarized influent strengths and effluent targets the plant must meet (BOD, TSS, phosphorus and ammonia levels) and said the commission monitors other parameters such as chlorides, E. coli (seasonal) and biosolids for land application. He said the facility serves about a 22,000-person equivalent across roughly 22 square miles, including the City of Delafield, Village of Hartland, Village of Nashotah and Village of Summit.

Trustees asked about Manema’s background and staffing; Manema said he has been with Delhart for nearly two years and previously worked for 32 years with the City of Beaver Dam utility. Manema and board members also discussed collection-system infiltration and inflow (I&I) after the August storm; he said collection-system analysis and targeted repairs or grouting of leaking manholes are part of planned work to reduce storm-driven flows.

Manema recommended continued capital planning, five‑year maintenance projects and regional coordination with member municipalities on new development so the collection system and the plant can absorb future growth. He did not request board action; the presentation was informational.