March discharge resolved with TCEQ



Due to the increased need for wastewater treatment capacity, the City of Liberty Hill was forced to bring its old sequential batch reactor (SBR) plant back online this spring, and a previously unknown issue with some other onsite work led to the discharge of 3,000 gallons on partially treated wastewater in March.

The discharge was unrelated to the operation of the new constant flow plant, City officials say.

When Pepper Lawson, one of the contractors working onsite, was removing a lift station, a number of supervisory control and data acquisition (SCADA) phone lines, which help monitor the systems and notify operators of issues, were cut. The City was unaware at the time the lines for the old plant had been cut.

“When they did that they cut through all of our lines that were to the SBR plant, so in doing that, when we got ready to pull the old plant back online not everything was operational and we didn’t know some of the alarms were not working,” said Wayne Bonnet, the City’s Public Works Director. “We wouldn’t have known that until we get into a situation that comes up.”

The investigation by the Texas Commission for Environmental Quality (TCEQ) was prompted in mid-March by three complaints alleging the plant was responsible for fish kills downstream, discharging chlorine, foam and bio-solids.

But following the investigation, the TCEQ report noted that claims of a fish kill at one site could not be substantiated because the complainant said they had already removed the fish. No other dead fish were found in a one-mile search upstream by investigators. A dead fish was found near the effluent discharge pipe at another location, but investigators said they believed the fish could have died from natural causes and had been partially eaten.

Efforts to test chlorine levels on multiple occasions in March were inconclusive and only a “slight trace of foam that was in accordance with permit conditions.”

The City had reported a chlorine release to TCEQ in January, and a violation was cited. Compliance documentation was received by TCEQ in March.

The City reported the discharge of the 3,000 gallons “of treated wastewater containing some solids” from the SBR plant and the investigators concluded that the discharge was “partially treated wastewater, containing solids.”

Bonnet said no untreated wastewater was discharged, and the claims of “solids” being discharged was not untreated material.

“That’s not the case,” Bonnet said. “There is no physical way to get untreated wastewater through the plant and out. The only way you can have solids discharged having to do with wastewater are treated solids, which are a whole different ballgame. Sludge is a combination of organics and in-organics, and decomposing organics, no matter whether it is from a wastewater treatment plant or vegetation, will leave a sludge-type material.”

The City was cited by TCEQ for the discharge violation, and has cleaned up the area around the effluent discharge pipe. Bonnet said they are also monitoring the site going forward.

“In speaking with TCEQ, we went over all this stuff and we’re moving forward,” Bonnet said. “We’re trying to get ready for the next expansion that’s going to help reduce nutrients that are put into the river.”