Hydrated lime for metals immobilization and explosives transformation: Treatability study

Area of Science:

• Environmental Science
• Soil Remediation
• Analytical Chemistry

Background:

• Hand grenade training ranges pose environmental risks due to explosives like RDX and TNT, and metals such as zinc, iron, and manganese.
• Contaminants can migrate off-site via surface water and subsurface leachate, impacting surrounding ecosystems.
• In situ remediation strategies are crucial for managing contamination at these training sites.

Purpose of the Study:

• To evaluate hydrated lime as a soil amendment for in situ remediation of explosives and metals at hand grenade training ranges.
• To assess the effectiveness of hydrated lime in reducing the off-site migration of RDX and key metals in soil leachate and runoff.
• To determine if hydrated lime can stabilize soil contaminants to promote explosives decomposition.

Main Methods:

• Bench-scale columns and mesocosm-scale laboratory lysimeters were employed to simulate field conditions.
• Soil samples from a hand grenade range were treated with hydrated lime.
• Leachate and runoff water were collected and analyzed for explosives (RDX) and metals (zinc, iron, manganese).

Main Results:

• Hydrated lime treatment resulted in a 26-92% reduction of RDX in leachate and runoff.
• A significant reduction of 66-83% for zinc was observed in treated soil samples.
• The soil pH was successfully maintained above 10.5, optimal for explosives decomposition.

Conclusions:

• Hydrated lime is a promising soil amendment for the in situ remediation of explosives and metals at hand grenade training ranges.
• The study demonstrated significant reductions in contaminant migration, suggesting effective stabilization.
• The findings support the potential for successful scale-up to field studies for real-world application.