Ex-Situ Blending – Shooting Range, AL

Overview

Site is a former shooting range and historic “dump”.
Earthen berm contained lead contamination from spent cartridges, approx. 100 cubic yards failed TCLP (total lead >1,000 ppm).
Eden conducted a treatability study to identify best fit chemistry for reduction/ stabilization.
Treatability study compared various blends of lime, Portland cement, metakaolin, silica fume, and calcium polysulfide.
Optimal treatment conditions created using a 5% calcium polysulfide solution followed by 7% Portland cement powder.

Scope included excavation and power screening using a trommel screener to remove rocks/debris (>1/2”).
Soils targeted for blending (approx. 100 cubic yards) were directed into lined roll-offs.
Remainder of the soils were transported to a Subtitle D landfill.
Soil blending was performed using a spray application of calcium polysulfide followed Portland cement.
After approx. 24 hours of partial curing, TCLP lead samples were collected. All TCLPs were ND which allowed Subtitle D landfill disposal.

In the middle of the job, a 3 to 4’ wide DEEP hole appeared in front of the bank.
Hole opens up to a wider passageway - possible mineshaft? – city archaeologists currently evaluating.
Required extra staging prior to loading soils – Beware of old dump sites!
A total of 1,245 tons of soil were transported off-site for non-hazardous waste disposal at a significant cost savings (total job cost <$170,000).