Report: Sludge dumped into river by wastewater plant caused algae

Test results show that an unauthorized dumping of sludge by a city-operated wastewater treatment plant in Liberty Hill was to blame for the algae that blanketed the South San Gabriel River in Georgetown this spring.

The excessive algae marred the appearance of the river, and people complained they could not safely get into the water, according to a report from the Texas Commission on Environmental Quality. The report does not say whether the water is still unsafe for recreational activities, but a local hydrology professor said he would not go in the water.

Raymond Slade, a retired U.S. Geological Survey hydrologist who teaches a water data collection class at Austin Community College, said he would not wade or swim in the river because of the sludge. He also said the sludge could affect drinking water supplies because the river feeds the Trinity Aquifer and the Edwards Aquifer, where many people have private wells.

Sludge, which is produced when solids are separated from liquids in the wastewater treatment process, can contain pharmaceuticals and chemicals that are dangerous to human health, Slade said.

Liberty Hill officials did not respond to repeated requests for comment about the report on the city-owned South Fork Wastewater Treatment Plant.RELATED: Is new wastewater treatment plant to blame for algae in river?

Wastewater treatment plants in Texas are required to handle sludge in a variety of ways, including taking it to a landfill, but they are never supposed to dump it into a river, said TCEQ spokesman Brian McGovern.

The agency will mail a proposed agreement within 60 days to plant officials with corrective actions to be taken and an assessed penalty, McGovern said. He declined to comment about the amount of the penalty. The TCEQ made several recommendations for corrective actions in its report, including that plant officials submit documents showing that the sludge has been removed from the river.

Following complaints from residents near Garey Park in Georgetown, TCEQ investigators in early May found mats of algae growing on wastewater sludge both 60 feet upstream of where the treatment plant discharges treated wastewater into the river and 3.6 miles downstream from that point, the report said.

When investigators re-evaluated the river May 31 after a heavy rain, they found pockets of sludge were still there, along with a bloom of algae covering 95 percent of the river’s bottom from 50 feet upstream of the discharge point to 1,000 feet downstream from it, the report said.

Extensive algae growth can deplete oxygen levels in the water, which can kill fish.

The South Fork Wastewater Plant began operating in January and replaced an older plant the city operated with the same name and near the same site that was discharging into the river until mid-March to early April, Wayne Bonnet, the city’s public works director, has said. He also has said the city of Liberty Hill was “using the best technology we can obtain to make sure are doing the best we can as far as the environment.”

The new plant has a permit that allows it to discharge up to 1.2 million gallons of treated wastewater into the river. Ultimately it will be allowed to discharge up to 4 million gallons per day into the river, Bonnet said.

The TCEQ report also said the plant had 53 violations involving discharges it had self-reported in the past 12 months. Those discharges included exceeding the allowed level of E. coli five times and the allowed level of total phosphorus 10 times.

“Although the multiple plant violations are disturbing, perhaps a larger problem is that the existing Liberty Hill wastewater permit is far too lax to prevent excessive algae growth in the river,” Slade said of the TCEQ report. He said the Liberty Hill wastewater permit allows maximum nitrogen levels that are 75 times the level that can cause a heavy growth of algae and allows phosphorous levels at 22 times the level that can cause dense algae.

He issued a summary of the TCEQ report with Mike Clifford, a contractor working with Save Barton Creek Association on the No Dripping Sewage campaign, a coalition effort to prevent sewage pollution and work for sustainable alternatives.

Dripping Springs reached a settlement in July with environmental groups including the coalition and landowners in which the city decided to not release wastewater into Onion creek but to use it instead to irrigate parks, medians and other grassy areas.

RELATED: It’s now Dripping Springs vs. Save Our Springs in sewage dispute

The No Dripping Sewage is now circulating a petition to get lawmakers to ban the dumping of treated sewage into waterways above the Edwards Aquifer, including the South San Gabriel River, Clifford said.

“It’s very tragic what happened with the South San Gabriel River,” Clifford told the American-Statesman. “If it can be some sort of lesson to bring focus to this issue, it might end up being positive.”

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