Pesky invaders

Photo: Jack Furlong, Fermilab

Pesky invaders
An overgrown zebra mussel population at Fermilab received a rude awaking when operations engineers treated the lab’s water cooling system in early June to remove nearly 4000 pounds of mussels.

Foreign to the Midwest and without any natural predators in the region, zebra mussels at Fermilab can become problematic when they coat the inside of the water cooling system pipes. One zebra mussel can produce more than a million offspring each year, says Fermilab’s Randy Ortgiesen, head of the Facilities Engineering Services Section (FESS). “If left untreated, they will eventually clog up the pipes, creating a huge problem,” he says.

To remove the zebra mussels, engineers injected a chemical called EVAC into an intake pipe and opened hydrants along the system to draw the chemical through the pipes. EVAC works by coating the gills of the mussels, effectively eradicating them. EVAC is not toxic when used in low quantities and does not harm fish and birds.

FESS engineers first treated the mussels in May of 2006 when they removed and flushed more than 15,000 pounds of them from the system. This spring’s treatment, which took a little more than 24 hours, was a follow-up measure to eliminate any zebra mussel offspring, called veligers, that made it into the system from the ponds.

Fermilab engineer Anne Lucietto says the treatment program has been successful so far. “It’s something we’re going to have to keep up with,” she says. “It’s been a challenge, but I think we’ve won this round.”

Amelia Williamson