The City of Lawrence, Kan., has selected McCarthy Building Co.’s water services team as general contractor for its $70-million project to improve the Kansas River Wastewater Treatment Plant.

The plant, which opened in 1956, receives nearly 80% of city wastewater, with an average flow of 8 million gallons per day. The improvements are required to meet the National Pollutant Discharge Elimination System (NPDES) regulatory permit requirements issued by the Kansas Dept. of Health and Environment. 

“As an end-of-line facility that processes and discharges effluent into the Kansas River, it’s critical that the plant utilize current technology and remain functional throughout the construction process,” said Leah Morris, engineering program manager for water and wastewater treatment for Lawrence. 

The scope of work includes replacing major motor control centers and upgrading electrical equipment, including transferring from city-owned transformers to utility-owned transformers, as well as converting from aeration to a biological nutrient removal treatment process, which includes converting four aeration basins to nutrient removal basins, converting an existing sludge holding tank to a return activated sludge ermenter, as well as upgrading to gearless, high-speed turbo blowers and a new thickened waste-activated sludge tank.

McCarthy also will build a new Supervisory Control and Data Acquisition (SCADA) facility with a new fiber loop, which will help plant staff more efficiently monitor and address system challenges. The contractor also will convert a chlorine contact basin into a new UV facility, and will upgrade grit handling equipment to current standards as well as additional upgrades, including valve replacements.

“As part of our strategic plan, this project will ensure we stay in compliance with our discharge standards and achieve our wastewater reliability and sustainability goals,” added Trevor Flynn, assistant director of municipal services and operations for Lawrence. 

Morris said one of the challenges will be to keep the facility fully operational and meeting all treatment regulations during construction. 

This is the city’s first wastewater project using a CM at risk delivery method. 

William Brennan, project manager for McCarthy, says the approach allows the project team to work through design challenges and construction risks during the design phase to mitigate impacts to the operating facility during construction and provides for work to continue while maintaining plant operations. 

The wastewater treatment plant has a dry weather capacity of 25 million gallons per day and an additional 40 mgd for wet weather.

Black & Veatch is the project consultant and McCarthy now is soliciting trade partners for the project. 

Preconstruction is underway currently with the project’s construction slated to begin in May 2023 and completion expected in fall 2026.