Industrial Tank Farm Release located in Fort Wayne, Indiana

Site Summary

Soil and ground water contamination by a wide range of organic chemicals was discovered at a manufacturing facility in Fort Wayne, Indiana. The contamination had migrated from a tank farm and subsurface piping into the surrounding soil. The contamination in the soil leached into the underlying ground water and spread across the property. The plume spread to cover an area of approximately 5,000 square feet.

Geology

The geology of the property was typical till plan silty clay with discontinuous, interbedded sandy silt and silt.

Hydrogeology

The first occurrence of ground water was at five to eight feet deep in a sandy silt lens less than five feet thick. The hydraulic conductivity was not known, but was expected to be relatively low.

Ground Water Contamination

The contaminants found at the site were mainly xylene, toluene and ethylbenzene. The total xylene concentration was up to 47,000 µg/L. The highest ethylbenzene concentration was 10,000 µg/L and the highest toluene concentration was 95,000 µg/L. Trace levels of chlorinated solvents and trimethylbenzene isomers were also part of the suite of contaminants.

Remediation Design

Petrox was introduced through one-inch diameter pvc injection points that were installed a using direct push sampler.

Petrox was injected into the ground water in three monthly applications of seven drums each. Calcium peroxide was added to boost the availability of oxygen for the metabolism of the contaminants. Seventy-five pounds of calcium peroxide were added during the first treatment, and 50 pounds were added during the second injection. The calcium peroxide was mixed with water to form an injectable slurry. The dissolved oxygen level was sufficiently elevated after the second injection such that a third application of calcium peroxide was not necessary.

Results

One month after the third Petrox injection, ground water samples were taken for laboratory analysis. The laboratory analysis showed a significant reduction in the contaminant concentrations. The maximum concentrations of xylene, toluene, and ethylbenzene were reduced by 98%. The table above shows the concentration reduction for the chemicals of concern.

The total Petrox cost for this site was $12,000.