Austin City Council last week gave the green light to a $1 billion upgrade to the Walnut Creek Wastewater Treatment Plant in East Austin, approving contracts to "design and construct significant enhancements and expansion” of the facility, according to a press release.

The expansion will increase the plant's treatment capacity, currently 75 million gallons per day, by 25 million gallons per day. Under the approved contracts, construction is expected to begin in 2025.
Enhancements and modernizations to rebuild or replace aging parts of the existing plant and will incorporate improved operational and environmental upgrades plantwide.
The project will replace the existing disinfection system with one that uses ultraviolet light, eliminating the use of chlorine chemicals for disinfection.
The new treatment process will also the nutrients that contribute to algae growth and blooms to benefit the health of the Colorado River downstream of Austin. A wall will be built around the plant to protect it from flooding.
The plant will continue to operate throughout construction, which is expected to start in 2025, will take place throughout the facility. In light of the complexities of operating the plant during construction and rehabilitating components that are nearly 50 years old, the city used what it calls a “construction manager at risk” process to deliver the improvements. will be used. The method "allows the contractor to be hired earlier and contribute to the design process in key areas,” according to the press release, "including constructability, maintenance of plant operations, scheduling, and coordinating work packages, and cost control.

The Walnut Creek Wastewater Treatment Plant was built in 1977 for a capacity of 18 million and was expanded in 1987, 1990, and 2005 to reach its current capacity. Between 2013 and 2024, the city invested $100 million in replacement and upgrades. Estimated for the current project are below.

Project Cost Overview (amounts are approximate):
Renewal Projects - $270 million

  • $160 million – Rehabilitation of Primary and Flow Equalization Basin Rehab
  • $90 million – Rehabilitation of Headworks #1
  • $20 million – Replace and upgrade Influent Lift Station

Expansion Projects - $440 million

  • $380 million – 25 MGD Capacity Expansion with nutrient removal and UV disinfection
  • $60 million – New influent and outfall pipelines

Treatment Conversion Projects - $220 million

  • $220 million – 75 MGD process treatment conversion to nutrient removal and UV disinfection

Protection of Plant Projects - $120 million

  • $80 million – Wet Weather Facility for high flows during rain events
  • $40 million – Flood Wall around plant