On the contribution of physicochemical processes for the retention of heavy metals within environmental barriers

FRANCISCA, FRANCO M.; GLATSTEIN, DANIEL A.

Cancun

Conferencia; XVI Pan-American Conference on Soil Mechanics and Geotechnical Engineering (XVI PCSMGE); 2019

PANAMERICAN ORGANIZING COMMITTEE de la International Society for Soil Mechanics and Geotechnical Engineering

Liners are engineered layers of low hydraulic conductivity typically designed to isolate solid, semisolid or liquid waste materials from the environment. The capability of a barrier to isolate, retain or sequester pollutants is of key importance, and controls the design of landfill and surface impoundments bottom liners. The purpose of this research is to highlight the importance of considering landfill liners as non-reactive materials where chemical reactions under certain circumstances may determine the mass transport through the barrier. We show that heavy metal ions can be sequestered within a barrier by adding a small amount of steel slags in the barrier. The retention of metal ions within a compacted barrier amended with steel slag is mainly associated with the increase of the pH of the barrier material. Then, the coupled hydraulic and chemical fluxes determine the percolation time for heavy metal transport through environmental barriers.