photo by: Courtesy of McCarthy Building Companies Inc.

A aerial photo shows the Kansas River Wastewater Treatment Plant, 1400 E. Eighth St., along the Kansas River.

Lawrence city leaders will soon receive a presentation on a $71 million project to reduce the pollution a sewer treatment plant discharges into the Kansas River.

As part of its meeting Tuesday, the Lawrence City Commission will receive a presentation from city staff regarding the project to update the Kansas River Wastewater Treatment Plant to improve the removal of nitrogen and phosphorus and make other updates. Both nutrients are found in human waste and damage ecosystems in high quantities.

According to the U.S. Environmental Protection Agency, nitrogen and phosphorus support the growth of algae and aquatic plants, but too much of those nutrients in the water causes algae to grow faster than ecosystems can handle. Significant increases in algae harm water quality, food resources and habitats, and decrease the oxygen that fish and other aquatic life need to survive. Large algal blooms can severely reduce or eliminate oxygen in the water, leading to illnesses in fish and the death of large numbers of fish. Some algal blooms are harmful to humans because they produce elevated toxins and bacterial growth that can make people sick if they come into contact with polluted water, consume tainted fish or shellfish, or drink contaminated water.

The city is required to meet certain environmental standards for removal of the nutrients, and under an agreement with the Kansas Department of Health and Environment it must comply with certain phosphorus levels by Dec. 31, 2027. The project, which has an estimated budget of $70.76 million, is already included in the city’s Capital Improvement Plan, and several million in contracts for professional services, engineering design and preconstruction have already been approved. Water and sewer infrastructure improvements are supported by city utility bills.

Tuesday’s presentation includes information about the project, including details about the scope of the work, the estimated costs and the duration. McCarthy Building Companies Inc. was selected as the general contractor for the project. The project includes required upgrades to target phosphorous removal, renovations of existing infrastructure and technology upgrades, according to presentation materials. Specific elements of the project include converting four water treatment basins to work under a different process, adding a Recycled Activated Sludge fermentation tank, converting a chlorine basin to an ultraviolet disinfection system, adding a new server facility, upgrading pump/valve structures, as well as replacing and adding other equipment.

The Kaw sewer plant, which is located at 1400 E. 8th St. along the Kansas River, began operating in 1956 and has seen various updates and additions over the years, according to the city’s website. The Kaw plant is one of the two City of Lawrence sewer treatment plants and handles 8 million gallons every day, equal to 80% of the city’s wastewater. The other plant, the Wakarusa Wastewater Treatment Plant, was constructed for $74 million and opened in 2018. That plant is located along the Wakarusa River.

A timeline of the Kaw sewer plant project goes through previously taken steps in the process, including design and bidding of certain elements. The timeline states work packages are currently out for advertisement and it’s anticipated that the final guaranteed maximum price for the project will be known in July. Construction is anticipated to last through Dec. 2026 and will be sequenced so the plant remains in operation.

The Lawrence City Commission will convene at 5:45 p.m. Tuesday at City Hall, 6 E. Sixth St.

Correction: This story was updated to provide the correct address of the plant.