Wastewater director outlines odor mitigation, force‑main repairs and $131M five‑year investment plan

Darren Mearing, director of the City of Dubuque Water and Resource Recovery Center, told the council on April 22 that the facility is addressing odor concerns, repair and reliability issues caused in part by an early‑December explosion that disrupted an anaerobic digester, and a multi‑year capital plan that staff say will total roughly $131 million over five years.

Mearing described the recovery center’s daily mission — treating wastewater, recovering resources and protecting public health — and said the facility treats roughly 6.7 million gallons of wastewater per day and typically removes about 94% of pollutants before discharge. He said the facility’s current design flow is 9.1 million gallons per day and that it is running at about 63% of design capacity (about 6.7 MGD). The facility employs 17.25 full‑time equivalents, including operations, maintenance and laboratory staff.

Staff highlighted several near‑term capital priorities tied to sewer‑collection capacity and system reliability. Mearing reported a projected $26 million Old Mill Road lift‑station project to boost Catfish Creek sewer‑shed pumping capacity, and a broader estimate of about $83.8 million of collection‑system improvements in the Catfish Creek sewer shed through FY29. He said the city plans roughly $131 million in sewer and treatment system investments over five years to support growth and to replace aging infrastructure. Mearing also described an exposed segment of a 42‑inch force main along the Mississippi River and said the city will partner with the U.S. Army Corps of Engineers on bank stabilization work, with the city contributing about $3 million of an $8 million project.

The presentation described odor‑reduction and reliability work: periodic dosing trials (ferric chloride and hydrogen peroxide) to limit hydrogen sulfide and struvite formation, installation of a new ferric‑dosing port for digesters, plans to reconfigure dosing locations and an odor‑monitoring proposal to install electronic “e‑nose” sensors at the facility perimeter to provide objective, real‑time odor measurements. Mearing said the city had received EPA findings on its industrial pretreatment program and is working to correct deficiencies; he said the program is expected to be in full compliance by the end of the fiscal year.

Mearing also described a high‑strength waste receiving and storage project (to meter hauled wastes and protect digester stability) with a budget estimate of about $7.3 million; he said the city applied for community project funding in the amount of $5.2 million to offset local hauled‑waste costs. The industrial control system rehabilitation (electrical control replacements) and other equipment upgrades were presented as priorities to improve reliability; staff noted supply‑chain problems and obsolescence as reasons for accelerated replacement timelines. Mearing said the facility is also pursuing a computerized maintenance management system and continuing efforts to reduce energy use per million gallons treated.

Council members commended staff for responsiveness and asked questions about liability and recovery for the December explosion; Mearing said the city had put the contractor on notice and is quantifying damages with legal staff. A public hearing drew no virtual comments and no formal council vote was recorded on the FY26 presentation.