Parents sometimes take pride in the fact that they can remove the toughest stains from their children’s sports uniforms. But workers at the former Stolper Steel site off of Highway 45 and Pilgrim Road are taking it a step further.
They’re getting their hands dirty and — cleaning the dirt.
Technically, crews with KPRG and Associates aren’t really making the dirt any cleaner, they’re restoring it to what it once was.
Over the past several weeks passers-by on the highway have seen a small army of dump trucks and back hoes meandering throughout the former dilapidated Stolper Steel site, which was torn down nearly a year ago.
In April, the from Western Industries and is investing $4.7 million to raze and clean the soil. Ryan Companies, a commercial real estate firm, is proposing to build a 90,000-square-foot development on the site, which would include medical, wellness and retail uses. Occupants are expected to move into the building sometime in 2013.
However, before construction on the actual building starts, KPRG needs to do a little cleaning.
It’s All About Chemistry
Throughout the Stolper Steel site, there are pockets of soil and groundwater that have been contaminated with trichloroethylene (TCE), which was a metal degreaser and solvent that was used decades ago in the industrial process. The chemical is known to cause cancer in the liver and kidneys of test animals.
The levels of contamination are at hazardous levels especially near an old rail spur near the back of the site where materials were loaded and unloaded. Therefore, the state Department of Natural Resources has required it be decontaminated before construction begins.
“We do have some groundwater contamination in this area, and it moves to the southeast of the site,” said Tom Hoffman, village engineering director. “However, the far ends of the monitoring network indicate that it’s fairly stable, and the chemicals are naturally degrading in the water and are staying on site.”
Therefore, residents near the site don’t need to worry about contaminated drinking water. The village’s Well #3 is a deep well nearest to residents, and there are no signs of contamination in that well, according to Hoffman. Everything has been low and on site.
“If there were any concerns, we would have already contacted residents in that area,” he said.
Cleaning Dirt Here Saves Time, Money
The village opted to treat the contaminated soil on site, rather than ship it to a hazardous waste facility in Peoria, IL, or in Michigan. The village’s approach saves time and a significant amount of money.
To treat the contaminated soil, work crews are using a hydrogen peroxide and ferrous iron solution to catalyze the chemical. When it reacts, it attacks the TCE and breaks it down into a fatty acid, which eventually breaks down to carbon dioxide and water, which are harmless natural elements.
Crews use a backhoe and a sprayer to mix the solution into the soil, and get a reaction to start.
“Any of the chemistry we are using is breaking down the contaminant, and the residual chemicals break down to natural elements,” said Richard Gnat of KPRG. “It’s a very quick reaction, and happens within 24 hours.”
The treated soil is then removed from the site, and shipped to the Waste Management landfill on Boundary Road.
KPRG is only half finished once the soil is decontaminated. The next step is to clear the TCE from the groundwater on site once the TCE is removed from the soil, which is the source.
To accomplish that, KPRG will map out 174 deep injection points where workers will shoot two types of solutions into the groundwater to break down the TCE. One injection will stimulate the natural decomposition processes already taking place, and a second will include microbes to speed up that process.
“We should at some point see improvements in the groundwater,” Gnat said. “The groundwater is currently improving and stable. In the meantime, they will be able to continue with the project.”
When the 90,000-square-foot building and parking lot are constructed, they will not only add value to the village, but also act as a cap to prevent TCE from seeping further into the soil. In the meantime, remaining TCE will simply degrade.
Hoffman said the labor-intensive portion of the soil remediation will be completed in July. However, the site will be monitored for two more years to measure TCE levels in the soil.
“Everything is going very well on the site. The contractor is doing a great job and things are moving along on schedule,” Hoffman said.