Austin Water has begun implementing new strategies to combat the prevalence of zebra mussels in its treatment plants.
Zebra mussels, which are tiny, invasive mollusks, first appeared in Austin waters in 2017 and have since infested the city’s drinking water sources: Lake Travis and Lake Austin.
To keep zebra mussels out of the water utility’s raw water infrastructure, Austin Water has started taking more aggressive steps to mitigate the effects of the troubling critters:
– Routinely clean and remove zebra mussel shells from screens and other infrastructure.
– Use divers to inspect underwater infrastructure and pressure wash grates and underwater infrastructure.
– Use rovers with cameras to inspect pipelines and underwater infrastructure not readily accessible by divers.
– Enhance protocols to evaluate taste and odor of drinking water more frequently.
– Install chemical systems to feed liquid copper sulfate pentahydrate into water pipes to keep zebra mussels from infesting pipes that take lake water to water treatment plants.
The new measures will help prevent issues like the city saw in February 2019 when dead zebra mussels attached to pipes at Ullrich Water Treatment Plant, causing water to smell and taste bad.
By dropping small amounts of liquid copper sulfate pentahydrate into the raw water pipelines, Austin Water officials have been able to keep zebra mussels from piling up in the pipelines.
“Zebra mussels are extremely sensitive to tiny, tiny amounts of copper and so any amount of copper in the water system will drive them away,” said Austin Water Director Greg Meszaros. “We’ll continue this system to keep them from building up again.”
“The number of shells that we’re removing from the system would indicate that the bulk of the mussels have died off,” Meszaros said.
Zebra mussels are still in the lakes.
Construction of the systems that feed the copper sulfate into the water were completed last month at Ullrich Water Treatment Plant and Davis Water Treatment Plant, officials said. In September 2019, a similar system was put in place at Handcox Water Treatment Plant.
The construction cost to build the system was $1.9 million, Meszaros said. The water utility will also spend up to $800,000 a year on chemical costs.
Meszaros said the copper sulfate is not going into lakes. Drinking water is still safe to use, because the chemical is only put in the water before it is treated at a plant, he said.
“We’re excited that we’re knocking them out,” Meszaros said.
Meszaros said the proliferation of zebra mussels in Central Texas is unbelievable after not having the invasive mollusks around three years ago.
“There were extreme infestations in our systems getting worse, so it was important that we deal with this,” Meszaros said.
Austin Water officials were surprised zebra mussels were attaching themselves to raw water piping because there’s no light.
“You wouldn’t think that a mussel would proliferate there but, man, they are hearty folks. They just really kind of glom onto the sides of the pipes and start clustering up. It’s amazing how fast they build up,” Meszaros said.
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