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 or toxic organics. These organics may not be adequately immobilized by the S/S processes. Adsorbents, such as activated carbon or organoclays, can be used 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 waste 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. Effective diffusion coefficients were determined for the release of organics in the presence of the sorbent, and compared with those when no sorbent was used. A relatively new analytical technique, Flow Microcalorimetry (FMC), was used to study the effects of different types of leachants on the desorption characteristics of phenol and aniline from the reactivated carbon surface. Even very small amounts (1–2% by weight) of this inexpensive reactivated carbon were found to be highly effective in preventing the organics from leaching from the S/S waste form.

VIKRAM M. HEBATPURIA, HASSAN A. ARAFAT, PAUL L. BISHOP, NEVILLE G. PINTO. Environmental Engineering Science. November 1, 1999, 16(6): 451-463. doi:10.1089/ees.1999.16.451.