AECOM, the global infrastructure consulting firm, has been selected by the City of Austin as prime consultant for the expansion of the Walnut Creek Wastewater Treatment Plant (WWTP) in Texas, the firm as announced. This project, aimed at modernizing the ageing plant, will increase its capacity from 75 million gallons per day (MGD) to 100 MGD, supporting Austin’s growing population and enhancing the city’s wastewater infrastructure.
The Walnut Creek WWTP, originally built in 1977 with a capacity of 18 MGD, has undergone multiple expansions to reach its current capacity of 75 MGD. With this latest upgrade, AECOM will help ensure the plant can meet future demands while improving operational efficiency and environmental sustainability. The project includes replacing outdated equipment, constructing a new 25 MGD treatment train, and building a 120-inch outfall line and structure. Furthermore, advanced features like 100 MGD cloth filters for wet weather treatment and a flood wall to guard against 100-year floods will be incorporated, reflecting updated flood risk assessments from the National Weather Service’s Atlas 14 study.
AECOM’s scope of work will include process, mechanical, civil, electrical, and structural engineering services. By leveraging its global expertise in nutrient removal and wastewater treatment, AECOM aims to improve effluent water quality and protect the local ecosystem while ensuring the plant remains fully operational during the upgrades.
Last May, the Austin City Council announced the approval of contracts for the design and construction of the enhancements and expansion of the Walnut Creek Wastewater Treatment Plant, totaling an estimated cost of over $1 billion.
The project costs are approximated as: $270 million for renewal projects, including rehabilitation of key components like the primary basin and headworks; $440 million for expansion projects to increase capacity by 25 MGD with nutrient removal and UV disinfection; $220 million for treatment conversion to upgrade 75 MGD to nutrient removal and UV disinfection; and $120 million for plant protection, including a wet weather facility and flood wall to manage high flows during rain events.
