PILOT-SCALE DEVICES FOR REMEDIATION OF MUNITIONS CONTAMINATED SOILS

An equipment is described for the remediation of(TNT) contaminated soi l in pilot scale setting. Devices were developed for the preparation o f soil samples and for the removal of water from soil after treatment of a soil slurry in a 60 L air-lift reactor, which was a prototype of larger commercial unit. The method was applied to clean up TNT-pollute d soil using Fenton reagent (H2O2+ Fe2+) as remedial technology. Pilot scale results were compared to those obtained at bench scale level. L aboratory scale experiments showed that 1% H2O2 + 640 mg Fe2+ L-1 redu ced TNT concentration from 400 mg kg(-1) to about 50 mg kg(-1), which was above the Nebraska Ordnance Plant's cleanup goal (17.2 mg TNT kg(- 1)). Adding the reagent incrementally rather than in a single dose was more effective in reducing TNT concentration at both bench and pilot scale. Faster removal of TNT was obtained in the pilot reactor: TNT co ncentration fell within 24 h below the clean-up goal and less cumulati ve amount of H2O2 (0.625 %) was required. The designed sieve size devi ce provided reliable and rapid screening of contaminated soil to a sie ve size (1 mm) optimal for reactor performance. The vacuum filter effe ctively separated water and soil from soil slurry, reducing handling a nd processing of primary residuals.