Webster City moves toward new treatment plant
Expensive, controversial project has long history
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City Manager John Harrenstein says Webster City's new wastewater treatment plant will be, "the largest, most expensive public works project in memory." If built for the estimated $31,881,680, there's nothing in sight to rival it. The final design calls for both demolition and new construction. Significantly, it will be built under the Construction Manager-at-Risk system, one of the first such projects to be so-managed in Iowa.
Demolition Comes First
Before the 1939 construction of the city's first wastewater plant, sewers emptied directly into the Boone River. The original facility had a primary clarifier, an open-air tank, where suspended solids are separated from raw sewage, and an anaerobic sludge digester, an enclosed tank where microorganisms break-down wastewater solids.
Today's clarifiers, and a trickling filter, which removes organic matter, both built of concrete, will be demolished. The existing rotating biological contactors, [RBCs] will also be demolished.
Repeated failure of the RBCs, which facilitate oxygen transfer, is a top reason the plant must be rebuilt. In its loan application to the Iowa State Revolving Fund, the city stated, "the existing plant has 5 RBC trains with 20 total RBC units, with 14 reaching the end of their useful life."
Extensive excavation is planned to remove obsolete utilities and pipes, and grade the ground for new construction. The control building, in continuous use for 87 years, will be renovated and remain in use as an office.
New Plant Based on Proven Technology
Snyder & Associates considered several scenarios to meet the city's future wastewater treatment needs. The selected alternative will see a new plant built on the site of the old one, with new treatment facilities and equipment.
During the design process, lead engineer Darin Jacobs, P.E., Snyder & Associates stressed the wisdom in retaining RBCs in the new plant. They're reliable in operation, and offer substantial savings in electricity use vs. other technologies. With high electricity costs a reality, this is an important consideration.
The new RBCs will be built on the site's west end. This makes good use of available ground, and allows more RBCs to be added if demand increases in the future. This goes a long way to control the plant's cost, while providing an option if the city's population grows faster than
projected, or if a new industry, with wastewater requirements, locates here. Thus, the new wastewater plant is an asset in Webster City's aggressive economic development plans.
Also planned are improvements to the headworks, digester, and laboratory. Headworks screen-out debris from sewage before more extensive clean-up begins. The outdated controls in today's plant will be replaced with modern electronics.
CMAR Management Employed for First Time
For 100 years, the accepted process for building large, capital projects, has been to accept the low-cost bid. Under Iowa Code, Chapter 73A.18, cities must award contracts to the "lowest responsible bidder."
Inaccurate cost estimates, change-orders, and long completion times, are common drawbacks to the low-bid system. Material shortages, supply chain disruptions and high inflation have magnified such problems, often leading to large cost-overruns.
The city designated Woodruff Construction, Ft. Dodge, Construction Manager-At-Large [CMAR] for the wastewater project in January 19, 2026. Since then, Jacobs, and Wastewater Plant Supervisor, Nick Knowles, have worked closely with Woodruff to ensure project plans and specifications are clearly communicated. Under CMAR, in which Woodruff ultimately assumes responsibility for building the plant for a guaranteed Maximum Price [GMP], such up-front communication can save both time and money.
CMAR only became legal in Iowa on July 1, 2022. Webster City's new wastewater plant is among the first large projects to be so-managed. While Woodruff is responsible for covering cost overruns due to its own estimating errors or non-performance of its workforce, GMPs can increase due to unforeseen construction problems or delays, a change in specifications or materials requested by the city, or weather or natural disasters.