McCarthy Building Companies has completed construction at the Tomahawk Creek Wastewater Treatment Facility in Leawood, Kansas, one of the world’s largest Aqua-Aerobic disk filtration system installations for dual-use filtration.
Begun in 2018, the project was completed on schedule and on budget. The ribbon-cutting was held May 4 of this year.
Located in Johnson County, Kansas, the $270 million expansion is about 30% greater than its previous footprint and represents a complete overhaul of the existing facility, which began operation in 1955 with numerous expansions and upgrades over the years.
The current expansion includes more than 30 new structures, more than 130 installed pumps, three tower cranes, 50,000 cubic yards of concrete, more than nine miles of underground utilities and 792 deep foundation drilled shafts.
The Tomahawk Creek WWTF was a joint project of Johnson County Wastewater, McCarthy Building Companies-Kansas City, Black & Veatch and HDR. Due to the complexity and tight schedule, Johnson County chose to use the collaborative delivery method of Construction Manager at Risk with McCarthy serving as the construction manager. In addition, McCarthy’s fully owned subsidiary, Castle Contracting, provided concrete services, making the project’s concrete all self-performed.
The Tomahawk Creek WWTF serves about 150,000 residents and is one of five wastewater treatment facilities serving approximately one-half million residents in the region. In addition to improving water quality while providing cost-effective long-term treatment solutions for Johnson County customers, the new facility has the capacity to treat wet and dry weather flows from 19 million gallons per day (MGD) to 172 MGD.
During much of the construction, flow received at facility had been diverted to Kansas City, Missouri. for treatment. Following the commissioning phase conducted from September 2021 through March 2022, all flows have been treated through the plant.