Relating monolithic and granular leaching from contaminated soil treated with different cementitious binders.

Area of Science:

• Environmental Engineering
• Geotechnical Engineering
• Waste Management

Background:

• Contaminated soils pose environmental risks, necessitating effective remediation strategies.
• Stabilization/solidification (S/S) is a common technique for immobilizing contaminants in soil.
• Understanding metal leaching from S/S treated soils is crucial for long-term environmental protection.

Purpose of the Study:

• To evaluate the leachability of metals from contaminated soil treated with various cementitious binders.
• To investigate the relationship between monolithic leaching and granular leachability over time.
• To provide design insights for S/S applications in contaminated soil remediation.

Main Methods:

• Soil contaminated with metals (Cd, Cu, Pb, Ni, Zn) and diesel was treated with 5% and 10% Portland cement, cement-fly ash, cement-slag, and lime-slag binders.
• Monolithic leaching tests were conducted over 64 days.
• Granular leachability was assessed on samples aged 49 and 84 days.

Main Results:

• Surface wash-off was the dominant leaching mechanism for monolithic samples.
• Granular leachability generally followed 4th and 6th-degree polynomial functions of monolithic leaching, except for Copper (multistage dose-response model).
• Leaching relationships were influenced by metal type, binder formulation, and curing age.

Conclusions:

• The study establishes a predictive relationship between monolithic and granular leachability for S/S treated soils.
• Binder selection and curing time are critical factors influencing long-term metal immobilization.
• Results offer valuable data for designing effective S/S strategies for contaminated soil remediation.