Chapter 12 - Stabilization/solidification of acid mine drainage treatment sludge

Abstract

Responsible management of acid mine drainage treatment sludge (AMD sludge), in accordance with increasingly restrictive environmental regulations, is of crucial importance. Stabilization/solidification (S/S) of AMD sludge is considered a sustainable management method before landfilling or disposal to limit its environmental impacts. Most S/S processes use General Use (GU) Portland cement as hydraulic binder during treatment. However, since GU cement is considered a nonrenewable resource with high energy-consuming and carbon footprint production, the reuse of low-carbon waste materials as replacement for GU in the S/S process is privileged for AMD sludge management. Hence, the objective of this chapter was to focus on the possible use of alternative GU binders, such as the pozzolanic additives [fly ash (FA) and ground-granulated blast-furnace slag (GGBFS)] in the S/S of AMD sludge. Chemical stabilization, in addition to the durability of the low-carbon S/S sludge composites, as a potential management technique for AMD sludge will be presented. An example of the assessment of the residue stability of AMD passive treatment and its S/S with GGBFS and FA will be discussed in detail. The main findings allow the evaluation of the efficiency of S/S of AMD passive treatment residues to better anticipate their potential fate in accordance with environmental criteria.