The ability of sorbent materials to adsorb and retain organic liquids under landfill conditions

A variety of sorbent materials are used in accident cleanup to contain spilled chemicals. The ability of these sorbents to retain liquids after being placed in landfills is dependent on capillary retention against the force of gravity, overburden pressure, and leaching by infiltrating water. Three commonly available sorbents were tested for their ability to retain water, xylene, acetone, TCE, and diesel oil. In all cases the sorbents retained less organic liquids than they did water against capillary drainage. Under certain simulated landfill conditions, retention of all liquids was less than that at saturation, as a result of the combination of gravitational drainage and overburden pressure which depended on the location within the landfill. For water and all the organic liquids tested except TCE, the retention increased, but in some cases only slightly with depth. For TCE the retention decreased with depth. Displacement with water resulted in large fractions of the retained organic liquids being removed from the sorbents. These results indicate that large volumes of pollutants may be released from both saturated and unsaturated sorbents placed in landfills. The use of saturation tests and consolidometer tests alone will not simulate retention under these conditions.