ACUITY Environmental Solutions’ own Jim Rouse will be presenting a technical paper at Battelle’s Eighth International Conference of Remediation of Chlorinated and Recalcitrant Compounds in Monterey, California on May 24th.

The paper highlights a remediation project conducted at a former plating facility, located in Muncie, IN, where the release of chromic acid resulted in extensive hexavalent chromium, antimony, arsenic and nickel contamination of the vadose and saturated environment. The impacted groundwater plume extended from the former site under adjacent streets, a park and into the surrounding residential area.


A series of bench tests established that the best reagent to remediate the contaminants was a suspension of nano-scale ferrous sulfide particles in an aqueous solution of polysulfide. Remediation of the vadose zone down to the water table at 15 feet was achieved using soil blending techniques which enabled the in situ application of the ferrous sulfide reagent.  In situ remediation of groundwater was achieved by introducing via pressure injection the ferrous sulfide slurry through a grid-based system of borings across the footprint of the plume.


Confirmative soil samples collected from the vadose zone showed that no samples had detectable hexavalent chromium and other contaminants had been geochemically fixated. Confirmation sampling of groundwater indicated complete remediation of nickel by the first quarter sampling event.  In addition, groundwater sampling also demonstrated that chromium and antimony had been remediated to project cleanup objectives after 5 quarters of sampling.  Detections of arsenic in groundwater at concentrations slightly above cleanup objectives still persist; however, detections are isolated and have decreased by orders of magnitude.  Current results will be presented as part of the paper.