Darren Strozewski of DCS Engineering delivered a presentation to council outlining three central issues contributing to the city's water treatment failure: instrumentation issues, programming issues and the presence of zebra mussels in the city's water pump intake systems.
Of these problems, Strozewski said the water sampling points were administered at the wrong locations; the contact time with the chlorine residual was lower than it should have been and could have resulted in potential exposure to microbial contamination; and there were issues regarding testing the water membrane's integrity and durability for water filtration. The sampling points and chlorine residual contact time issues were corrected Sept. 20, while the membrane integrity test was updated Oct. 1 and programming at the water treatment plant was fixed Oct. 18.
The four types of violations the city received from the Texas Commission on Environmental Quality, divided into two groups, included Tier 2 and Tier 3 violations, Strozewski said. Tier 2 violations were related to cryptosporidium, a parasite whose removal was less than the required amount as outlined by the TCEQ. Due to the incorrect data reports compiled by the city previously, city staff confirmed that whether there ever was a presence of cryptosporidium is unknown.
With regards to zebra mussels, Strozewski said the invasive species, first found in Lake Travis in June 2017 and were discovered in Lake Pflugerville in August 2019, multiplied at a rate much higher than anticipated.
"They effectively grew faster and showed up in the plant faster than we expected," Strozewski said.
Some of the trains used in the plant's pump systems had significant damage—approximately 75%—to their exterior, resulting in larger holes in the water membranes and distinct breakage patterns. The plant has five trains, and Strozewski said that when the city starts reaching its maximum water usage per day during the summer, the goal is to have all five trains operational and in service by June 1.
Strozewski added that the plant, first brought online in 2006, now has a peak flow of approximately 13 million gallons per day, with the plant rated at 17 million gallons a day. As the city grows, Strozewski said, so, too, will some of the "imperfections" that can lead to performance issues.
"I think we need to take a serious look at expanding and increasing the productivity of it," Council Member Jeff Marsh said during council's discussion, later adding: “There’s things that we can do in the future to make this a non-issue for councils 10, 20 years down the road.”
Remedies the city has made and continues to administer, Strozewski said, include leadership changes made regarding the plant's lead operator in May as well as now implementing standard operating procedures, or SOPs, that had not been previously enforced.
City Manager Sereniah Breland confirmed that she did engage in a professional service contract Sept. 12 once she was made aware of the lack of SOPs, bringing in a third party to complete an assessment and start conducting SOPs. Breland also added that the city is currently conducting a job search to help with "staffing up to a level that we need to be at."
“It is the highest priority we have in the city right now, to protect public health for water," Breland said. "For years, it has been done wrong. We’re going to make it right."