Assessment of Heavy Metals Inactivation in Contaminated Soil by Coal Fly and Bottom Ashes

The study compared coal fly and bottom ashes for their ability to inactivate metals and lead to soil remediation. Soil was artificially contaminated with Cu, Zn, Pb and Cd at five degrees. Next, both ashes were added at five rates: 0, 0.5, 1.0, 1.5 and 2.0% and all treatments incubated. Data showed that for moderately contaminated soils, ash rates of 0.5 - 1.0% were efficient from 40 to 70% for Zn and Cd, and raised markedly to between 70 and 93% for Cu and Pb. For extremely contaminated soils, the rates of ashes at 1.0, 1.5 and 2% were much more efficient (60 - 80%). The use of fly and bottom ashes for metal inactivation and soil remediation should give greater consideration to the effect of pH and the type of heavy metals than the content of SiO₂and Al₂O₃. Fly ash displayed superior inactivation and remediation effects to the bottom ash.