Granular Activated Carbon Treatment 1
Granular activated carbon (GAC) treatment is a physicochemical process that removes a wide variety of contaminants by adsorbing them from liquid and gas streams [1, p. 6–3]. 2 This treatment is most commonly used to separate organic contaminants from water or air; however, it can be used to remove a limited number of inorganic contaminants [2, p. 5–17]. In most cases, the contaminants are collected in concentrated form on the GAC, and further treatment is required.
The contaminant (adsorbate) adsorbs to the surfaces of the microporous carbon granules until the GAC becomes exhausted. The GAC may then be either reactivated, regenerated, or discarded. The reactivation process destroys most contaminants. In some cases, spent GAC can be regenerated, typically using steam to desorb and collect concentrated contaminants for further treatment. If GAC is to be discarded, it may have to be handled as a hazardous waste.
Site-specific treatability studies are generally necessary to document the applicability and potential performance of a GAC system. This chapter provides information on the technology applicability, technology limitations, a technology description, the types of residuals produced, site requirements, latest performance data, status of the technology, and sources for further information.