Wastewater management is a critical function of any town or city. Austin City, which currently has 2,274,000 people inhabitants within its city limits, with that number expanding rapidly, needs higher capacity for wastewater disposal and management. 

To address the current requirement and prepare for the future, the Austin City Council recently approved funds for the upgrade of the Walnut Creek Wastewater Treatment Plant in East Austin. The City Council has allocated $1 billion toward this project. This is one of the two wastewater facilities that treat the water in the sewer system before dumping it into the Colorado River. 

The current plant, built almost five decades ago, has undergone regular enhancement to meet the city's growing needs. It initially had a capacity of treating 18 million gallons of waste, and after undergoing expansion in 1987, 1990, and 2005, it can currently process 75 million gallons of wastewater per day. This current upgrade will enhance the capacity by an additional 25 million gallons per day. 

Austin Water Director Shay Ralls Roalson stated, "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." 

The project scope includes replacing the existing disinfection system that uses chlorine with a new one that will use ultraviolet light. Some of the older parts of the plant will be replaced or rebuilt with modern enhancements to allow for better operational and environmental outcomes.

The new treatment that will be introduced will take care of removing nutrients that contribute to algae growth downstream of the Colorado River, which impacts the river's health.

A wall will also be built along the facility to prevent flooding. 

The new expansion will start in 2025, but during the ongoing construction work, the facility will not be shut down and continue operations. 

This factor will make the work much more complex, and to mitigate this, the City will be using the "construction manager at risk" process. In this process "the contractor is to be hired earlier and contribute to the design process in key areas," and will include constructability, maintenance of plant operations, scheduling, and coordinating work packages, and cost control. 

The biggest contract approved has gone to MWH Constructors, which is approximately around $900 million. An additional $71 million was added to an existing contract with AECOM Technical Services, to make it $131 million.

The Austin City Council also authorized four changes to existing city contracts, totaling over $150 million in fresh funds for various plant upgrades. These include:

1. CDM Smith received a contract worth $2.85 million for the plant's WWTP Influent Lift Station
2. Carollo Engineers received $9 million for the WWTP Headworks #1 Improvements
3. MGC Contractors and Black & Veatch received $127.3 million and $17 million, respectively, for Creek Primary Clarifier and Flow Equalization Basin Rehabilitation

The City Council has provided an approximate breakdown of the project cost:

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 the 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 the plant