Leaching behavior of selected aromatics in cement-based solidification/stabilization under different leaching tests

Stabilization/solidification (S/S) is a common technique used for treatment of heavy metal-contaminated wastes prior to land disposal. Unfortunately, most predominately inorganic hazardous wastes also contain some hazardous o r toxic organics. These organics may not be adequately immobilized by the S /S processes. Adsorbents, such as activated carbon or organoclays, can be u sed in conjunction with the S/S reagents, but they are expensive, and often make the process noncost effective. This research investigated the use of inexpensive reactivated carbon for organics immobilization within the S/S w aste matrix. Three commonly found organic contaminants-phenol, aniline, and naphthalene-were used in this research study. The Toxicity Characteristic Leaching Procedure (TCLP) and the American Nuclear Society Test (ANS 16.1) were performed to investigate the leaching behavior of these organics. Effe ctive diffusion coefficients were determined for the release of organics in the presence of the sorbent, and compared with those when no sorbent was u sed. A relatively new analytical technique, Flow Microcalorimetry (FMC), wa s used to study the effects of different types of leachants on the desorpti on characteristics of phenol and aniline from the reactivated carbon surfac e. Even very small amounts (1-2% by weight) of this inexpensive reactivated carbon were found to be highly effective in preventing the organics from l eaching from the S/S waste form.