AUSTIN, Texas — Over the next six years, the Walnut Creek Wastewater Treatment Plant will undergo a major expansion project that Austin Water leaders say will finally help the plant keep up with the city’s growing population.
“It’s definitely a generational project for the future of Austin,” said Charles Celauro, the assistant director of engineering and technical services for Austin Water.
The Walnut Creek Wastewater Treatment Plant is one of only two wastewater treatment plants in all of Austin. It opened back in 1977, with the capacity to treat about 40 million gallons of water per day.
In the early 2000s, the plant upgraded to treat about 75 million gallons of water per day, but just in the past year, the plant has exceeded 90% capacity several times.
“The demands have outpaced capacity,” Celauro said.
Austin Water leaders said when a plant exceeds 90% capacity, that triggers a state requirement to expand the treatment plant. Back in May, Austin City Council approved a plan worth $1 billion to expand the plant and improve the existing infrastructure.
“It is definitely a generational project for the future of Austin,” Celauro said.
With the expansion, the treatment plant will now be able to treat up to an additional 25 million gallons per day, for a total capacity of about 100 million per day. The billion-dollar project will also help replace outdated equipment for areas like Head Works, the first step in the treatment process, where they separate inorganic solids from the water.
“It is all the original equipment, original electrical and controls still in operation, but it is incredibly difficult to maintain,” said Lauren Kin, the managing engineer for Austin Water.
The project will add more capacity to the aeration basins, which is the next step, where bacteria will eat on organic matter to clear the water. It will also upgrade the basins by using more modern practices, like biological nutrient removal.
“Basically, we’re going to remove phosphorus from the water and other nutrients, and that’s going to help the quality of the water that we’re going to discharge into the Colorado,” said Agmed Weber, the wastewater treatment operations manager.
Another significant improvement in the plan will be to add about 12-foot floodwalls around the entire plant. Austin Water says it’s important because the plant has experienced two floods over the years, but even more so because the facility is now in the 100-year floodplain.
“We do want to protect the existing structure, and of course the investments that we’re making over the next 10 years,” King said.
Austin Water says the expansion project will start in the summer and wrap up in 2031.