Sludge management is an ever-increasing issue as the inventory of sludge continues to grow through perpetual pump and treat. Current sludge management practices, in general, are ad hoc and frequently do not address long-term storage, and in some cases, long-term stability issues. While there are a variety of sludge disposal practices that have been applied, many have not been fully investigated and monitoring data on the performance of these technologies is limited and not readily available. Further research is required into disposal options that can recover metal, densify existing sludge or safely dispose of the material in a way such that it can be either easily reclaimed or disposed in mine workings. Promising options must be both technologically feasible and also cost effective. In addition, sludge management options must be able to meet increasing environmental standards and regulatory pressures.

This report contains a review of technologies related to the management of acidic drainage treatment sludges. The bulk of the report assesses technologies available for sludge management including conventional disposal technologies, reprocessing options for metal recovery, novel sludge reuse technologies and reclamation of sludge areas. The sludge management toolbox is limited. The knowledge gaps are identified and discussed, and recommendations are made for further work.

With such limited data available on sludge characteristics, standardized methods, and long-term laboratory and field performance, it is important to focus efforts to address some of these gaps in the knowledge base. Best practices for sludge management and standard testing methodologies need to be defined. The development of Sludge Management Guidelines is fundamental in ensuring that appropriate management options for sludges are implemented.