“The cleanup was complicated enormously by the fact that
it wasn’t just mercury, and it wasn’t just PCBs. It was mercury
mixed with PCBs which caused the problem,” added Scott
Wilson, a vice president at Ayres who served as client liaison
Drone photograph of new Waunakee Public Library on former
Waunakee Alloy foundry site. Note new pedestrian pathway
along revitalized Six Mile Creek.
on the project. “Companies permitted to incinerate PCBs have
permits that prohibit incineration of anything with even a faint
touch of mercury on it.”
Current federal regulations regard elemental mercury as a
Resource Conservation and Recovery Act (RCRA) waste, while
PCBs are a Toxic Substance Control Act (TSCA) waste – “and
these things should never meet,” Steiner noted, explaining how
federal regulations advise disposing of PCB waste by incineration
but prohibit incineration of mercury.
“After a thorough evaluation of state and federal environmental
regulations, we advised the Village to contact the Department
of Natural Resources and call in the Environmental
Protection Agency (EPA) to perform a time-critical removal
action,” Steiner said.
The EPA conducted the removal action – a more than $1 million
clean-up effort – in July through November of 2015. With that
complete, Ayres conducted a site investigation and prepared
a remedial action options report. The firm also completed a
remedial design report, a materials management plan to manage
the soils and cap the site, wrote specifications for demolition
of the buildings, and developed a TSCA self-implementing PCB
cleanup plan for the PCB release inside the building.
An ‘interesting find’
The challenges didn’t end there. During Ayres’ investigation,
staff noted unusually wet near-surface soils, but it wasn’t
until demolition began that the source of that excessive
moisture was uncovered.
“The bulldozers and the backhoes were encountering wet soils
a foot or two below the ground surface. It just wasn’t right. The
water table was known to be lower than that, and there was
no indication, based on the geology of the site, that perched
groundwater would be encountered,” Steiner said.
“When we were ripping out concrete floor slabs in one area of
the building, the contractor came across a flowing artesian well
a few feet below the ground surface. Groundwater was flowing
4 | TRENDS
Ingenuity, Integrity, and Intelligence.