Megan Navarro
WIMBERLEY — The city of Wimberley is not moving forward with a wastewater treatment plant at Blue Hole Regional Park.
This comes after Wimberley City Council unanimously voted at its Aug. 21 meeting to not approve the renewal of a Texas Pollutant Discharge Elimination System (TPDES) Permit with the Texas Commission on Environmental Quality (TCEQ).
The permit would allow the city of Wimberley to operate a wastewater treatment plant at Blue Hole. According to the permit application, the facility would be permitted for an initial capacity of 9,450 gallons per day with a future capacity of 75,000 gallons per day.
Discharges from the facility, the application continued, were expected to contain five carbonaceous biochemical oxygen demand, total suspended solids, ammonia nitrogen, Total Phosphorus, dissolved oxygen and E. coli.
“Domestic wastewater will be treated by an activated sludge process using the extended aeration mode in the interim phase. Wastewater will be pumped into the plant where it will enter the aeration basin through an initial screen,” the application reads. “The influent will then pass through the aeration zone into a clarifier. From the clarifier, the effluent will be pumped to a drip irrigation field adjacent to the plant site.”
There was also a provision for the disposal of treated wastewater via drip irrigation system and subsurface application on approximately 2.16 acres.
Council member Rebecca Minnick said that the discharge permit was initially issued in 2005, just five years before the city of Wimberley had been incorporated. It was issued with the idea that the city would have a sewage treatment plant because the downtown lots were undersized to have septic systems.
“When you walked over the bridge downtown, it smelled like [sewage] and, over time, it got worse and worse. The common wisdom was that it was compromised septic systems that were right on the creek and they were older septic systems,” she explained. “So, this whole thing of having a city-owned sewer downtown was very attractive and it's something that was advanced to clean up the creek, but there was never any money.”
Since the initial issuance of the permit, the permit would have to be renewed every five years if the city wished to keep it active. Council renewed it one last time in 2020, but, now, five years later, opted to not renew it again.
Rather than pursuing a city-owned septic downtown, the city contracted with Aqua Texas to have a wholesale agreement, where the city would have the infrastructure to get the sewage or effluent to the company, who would process it. This ultimately helped clean up the creek and not have any odor downtown anymore for the last five years, Minnick stated.
Working with Aqua Texas through the wholesale agreement, as well as the residents to conserve water, is a less costly option for the city — compared to renewing the discharge permit.
“We want to conserve water. We want to reuse water wherever we can in Wimberley and there are needs for the park. So, we could, if we can treat this sewage to level one, which is not to drink, but it is good to water the ground and to flush toilets and things like that. If we want to do that, we have other ways of doing that that are much less expensive than a package plant [or] a treatment plant. We can make use of new technology and new technology is happening all the time,” she said.
“The discharge permit, the idea is that the concept was that you would discharge level one effluent into the creek. The only times you would do that would be if there was a significant rain that outpaced the ability of the storage and our rain, even in the last five years, has got to be much less,” Minnick continued. “We're still in a drought. The likelihood that we would bring that much, and you still would have this discharge, is a little worrisome … and we have already solved this issue of the odor and getting the downtown businesses on the sewer system.”
Minnick added that the city also has an opportunity to look at doing more rainwater collection and "environmentally responsible solutions” in the park.
Wimberley City Council will meet again at 6 p.m. Thursday, Sept. 18.
