An improperly installed containment system appears to be the cause of contaminated groundwater at the former RB&W site at 800 Mogadore Road.
For more than a year city officials, the Ohio EPA, a local environmental firm and the out-of-town property owners have been trying to find out what was causing groundwater test wells at the former manufacturing site, now a brownfield, to show increased levels of contaminants.
Results from groundwater monitoring wells at the approximately 18-acre property, owned by Memphis, TN, based Thomas & Betts Corp., have shown that contaminants in groundwater at the property have gradually increased since 2008.
In 2005, an underground clay slurry wall and artificial cap liner were installed by Pittsburgh-based Geo-Con Environmental to seal in the chemical remains of five former open-air oil lagoons that once covered about 1.8 acres at the south end of the property. Samples pulled in July 2011 from groundwater monitoring wells surrounding the sealed area — what looks like a peaceful, grassy meadow — showed the containment system was likely responsible for leaching contaminants and causing the increased level of groundwater pollutants.
This summer, city officials agreed to partner with Thomas & Betts Corp. to conduct a "failure investigation" to study the slurry wall and try to find the cause of the increased contaminants in groundwater there.
The engineering firm that handled the failure investigation, Monroeville, PA, based D'Appolonia, determined that the slurry wall indeed appears to have failed to contain the remnants of those open-air oil pits. The firm dug a test pit to examine the wall itself and used equipment to measure groundwater levels.
The slurry wall is most easily interpreted as a bath tub — a thick wall of clay underground that surrounds the former oil pit area and extends down to a clay base beneath the soil. The slurry wall was then capped with a geomembrane material and clean soil — the grassy, curved meadow at the property's southern end — in an effort to seal in the chemical remnants of the pits from migrating outside the slurry wall.
D'Appolonia's investigation determined that the slurry wall was built as much as 3 feet too low beneath the surface level and the cap where a test pit was dug, thus leaving spots of unsealed soil where the groundwater could spill out of the sealed area between the cap and the slurry wall and into the surrounding soil, according to the firm's report.
"The observations from the test pit indicate that the low permeable cap is not effective as a barrier to groundwater movement and that such movement appears to occur, at least within the vicinity of the test pit," D'Appoloni's report states. "Leakage from the containment ... is the most reasonable explanation for the detection of increasing (contaminants) in groundwater immediately downgradient of the containment."
The firm's analysis also found that the slurry wall is working in other areas. But the wall was meant to keep water out, and the presence of groundwater within the containment system indicates that there's a leak allowing water to both enter the system and leave.
Compounding the problem is the fact two of the city's sanitary sewer lines cross through the slurry wall on their way to the water reclamation facility. Whether the area where the lines cross through, which is sealed, is contributing to either problem is unclear, according to D'Appolonia's report.
Officials involved in the cleanup, including at the Ohio EPA and the property owner's environmental consultant, Mentor-based Hzw Environmental Consultants, have suspected the slurry wall for months to be the cause of the contaminant increase.
Bridget Susel, director of Kent's Community Development Department, said the $1.34 million Clean Ohio Revitalization Fund grant awarded to the city for the property includes repair costs for the slurry wall failure.
Whether the property owner, Thomas & Betts Corp., which paid for the wall's installation in 2005, seeks some kind of reparations from GeoCon Environmental is a decision the owner and not the city would make, Susel said.
The city also is working with the property owner to pursue an "urban setting" designation for the property from the state.
"In laymens terms, it basically says nobody’s going to be drilling a well and using it for drinking water around the site," Kent Economic Development Director Dan Smith said previously.
The vacant land remains a focal point among city leaders for redevelopment into a technology park.
Smith said the 15 acres north of the 2-acre containment area is mostly clean of contaminants and could already be redeveloped. The containment area will likely never be allowed to be disturbed.
He said in a recent interview the city plans to apply for a grant of about $1 million from the state economic development office to help construct the technology park.
"We plan to put an application in (this month)," Smith said. "That (money) can be used for bricks and mortar. It can be used to put a street in. We do have a private company that we've been negotiating with that fits as an anchor tenant. It is high tech."
He said Kent leaders asked state officials if the city could move forward on redeveloping the northern portions of the site, which have been cleared of contaminated soils.
"The state said that would be fine, we could do that," Smith said.
The next step in the clean-up process is for the city to hire a certified professional to oversee repairs of the slurry wall.