Grout and Slurry Walls for Hazwaste Containment: The Down Side

ABSTRACT

The results of engineering case studies at two Superfund sites have demonstrated the inability to contain hazardous wastes with grout curtains and slurry walls. The nature of the chemical wastes attack and change the porosity and properties of these engineered containment structures. For example, it has been shown that the permeability of a bentonite slurry mixture can increase by several orders of magnitude in the presence of chemical waste leachate. These structures are also difficult to key or seal to bedrock which itself may be inherently fractured or become fractured during the keying process. Thus, grout curtain and slurry wall containment structures should only be viewed as a temporary means of reducing the influx of groundwater into the wastes and not as long term permanent remedies in lieu of detoxification, conversion or destruction of the wastes.