Dive Brief:

• More than $1 billion in upgrades are coming to the Walnut Creek Wastewater Treatment Plant in east Austin. The plant, one of Austin Water's two major facilities, treats wastewater from the city's sewer system before routing it back into the Colorado River.
• The Austin City Council on May 30 approved multiple contracts to design, rebuild and replace aging parts of the 47-year-old plant and to improve its operational and environmental features. A wall will be built around the facility to protect it from floodwaters and make it more resilient to extreme weather.
• Every area of the plant will undergo construction, and all work will take place as the facility continues to operate, according to a City of Austin news release. Construction on the expansion is expected to begin in 2025. 

Dive Insight:

The project will be built via a construction manager at risk delivery method, which allows the contractor to be hired earlier and contribute to the design process in key areas like constructability, maintenance of plant operations, scheduling and coordinating work packages and cost control, according to the release.

The biggest contract approved for the expansion of the plant, with Broomfield, Colorado-based MWH Constructors, is listed in city documents as not to exceed $900 million. The city also added $71 million to an existing contract with AECOM Technical Services, bringing the total amount to a maximum of $131 million, city documents show. 

The Austin City Council also approved four amendments to existing city contracts granting a total of more than $150 million in new funding for different upgrades to the plant, according to a memo from Shay Ralls Roalson, director of Austin Water.

Those contracts are:

• Boston-based CDM Smith, an additional $2.85 million for The Walnut Creek WWTP Influent Lift Station.
• Arlington, Virginia-based Carollo Engineers, an additional $9 million for Walnut Creek WWTP Headworks #1 Improvements.
• An additional $127.3 million for MGC Contractors and $17 million for Overland Park, Kansas-based Black & Veatch, Walnut for Creek Primary Clarifier and Flow Equalization Basin Rehabilitation.

Plans involve upgrading the treatment process for the existing plant and the expansion in order to reduce the nutrients that contribute to harmful algae growth in the Colorado River, per the release. The project also entails replacing the disinfection system to use ultraviolet light, which Austin Water said will eliminate the use of chlorine chemicals for disinfection and will make the plant safer for workers and community members.

The expansion will add treatment capacity of 25 million gallons per day to serve the area’s growing population, according to the release. The existing plant is currently permitted to treat 75 million gallons per day.

“With these investments, every part of the treatment process will be enhanced and upgraded, and we will be prepared to serve the growing needs of our city,” said Roalson in the release.