A coding error in Pflugerville Surface Water Treatment Plant's regulations system was responsible for the city's Dec. 24 water treatment issue.
According to Darren Strozewski of DCS Engineering, an engineering consultant firm based in Travis County, the programming error occurred during a two and half hour time frame on Dec. 24, potentially affecting 80,000 gallons of water. This is 2% of the city's daily water usage.
“This was not a recurrence that I wanted to happen," said Strozewski before council at a Jan. 14 meeting.
The Texas Commission on Environmental Quality issued a Tier 2 violation to the city of Pflugerville on Jan. 10 for its programming error. The Tier 2 violation does not suggest that the city's water supply has been compromised, however, so it is safe for residents to consume.
The plant's automated system regularly performs direct membrane integrity tests once a week, reported Community Impact Newspaper. For TCEQ's direct membrane integrity tests, water supply passes the exam if it is less than .33 pounds per square inch per minute (PSI).
Train No. 2 had a registered amount of 0.35 PSI/minute, but the city's software system incorrectly reported the test had passed and returned the train to water production. Since then, Pflugerville has since been manually testing each of the treatment plant's membrane integrity exams to avoid another error. SUEZ Water Technologies, owner of the city’s software system, has already worked with DCS Engineering to update the coding formula in the current water plant software.
According to Community Impact Newspaper, the city has performed membrane repairs on Trains No. 1, 2 and 4; replaced the city's river pumps; submitted to TCEQ a contact time study to ensure that the treatment plant's water is effectively administering chlorine; relocated its Manville Water Company distribution line; and went out for quotes on standard operating procedures.
Moving forward, Council Member Doug Weiss requested Breland present quarterly public updates on the city's asset management processes.