Prospect of utilizing coal mine drainage sludge as an iron source for value-creating applications

Large quantities of sludge produced from acid mine drainage (AMD) treatment require proper disposal due to their potential environmental impacts. Sludge handling and disposal practices are used to address the environmental concerns, and they represent significant economic liability. As a sustainable management strategy, utilization of AMD sludge for beneficial applications can not only eliminate or alleviate the need of disposal, but create value from the materials. In particular, coal mine drainage sludge (CMDS) can potentially be used for various applications due to its high ferric content. However, conventional coal mine drainage (CMD) treatment and sludge disposal practices do not necessarily produce sludge with optimal properties for the applications. This calls for development and implementation of application-driven treatment and sludge management practices to generate sludge materials tailored for the target applications. This study systematically characterized causal linkages between various CMD treatment and sludge disposal factors and sludge properties reported in literature. It also reviewed and documented optimum sludge properties for beneficial applications including adsorptive pollution control, microbially facilitated ferric reduction, and catalytic degradation of wastes. The systematic understanding was then used to develop CMD treatment and sludge disposal guidelines that would facilitate production of application-specific sludge materials. Such an application-driven CMDS management approach, if successfully implemented, is expected to bring about modernization of waste management infrastructure and create values in mineral producing regions.