Remediation of PCE/TCE plume under leased building: Combination SVE and Permanganate Injection, CT
200,000 SF Leased Building had chlorinated solvent in the unsaturated zone and in groundwater
The Client had owned the building, used it for manufacturing and sold it, retaining liability for environmental cleanup of solvents under the slab.
The building was leased back for a limited period at high cost, requiring schedule maximum efficiency of remedy.
Building has limited ceiling height (12') and a smooth concrete floor that had to be restored after SVE piping installation below the slab.
Soil conditions indicated a maximum 25 foot spacing of SVE wells; over 80 wells were constructed and plumbed in 3 weeks.
Over 50 MnO4 injection points were installed at the same time.
Ten storage and mixing tanks (30,000 gallons total) were mobilized and plumbed into the injection system
Concrete floor was repaired and two (zoned) SVE plants were installed (600 and 200 CFM).
Both KMnO4 and NaMn04 were injected to balance efficacy and cost; over 300,000 gallons of solution were injected during the 30 day period authorized by CTDEP.
All operations were completed on schedule.
During follow up evaluations, a storm drain under the building was accidentally broken and injection solution was discharged to a local creek. A significant emergency response was successfully coordinated over a holiday weekend to contain the discharge and minimize environmental impacts.
Groundwater monitoring indicates that the oxidant is successfully reducing PCE/TCE levels to compliance targets.