Zeolite-amended backfills for enhanced metals containment via soil-bentonite vertical cutoff walls
Low hydraulic conductivity (k), soil-bentonite (SB) vertical cutoff walls are commonly used to contain contaminated groundwater in geoenvironmental applications. The low k of the SB cutoff walls is attributed, in part, to the high swelling property of the bentonite component of the backfill. In addition, the high cation exchange capacity (CEC) of the bentonite, typically on the order of 80 to 150 cmolc/kg, imparts some intrinsic attenuation capacity to the backfill for cations (e.g., metals) via cation exchange. However, due to the low amounts of bentonite in typical SB cutoff walls (i.e., < 10 ...