A proposed protocol for evaluation of solidified wastes

Solidification technologies are potentially useful for improving the chemical and physical properties of hazardous wastes to the extent that they are suitable for less expensive disposal or even utilization. Unfortunately, in most jurisdictions worldwide, there is no mechanism for reclassifying a treated, previously hazardous waste, as non-hazardous. In response to the need for such a mechanism, the Wastewater Technology Centre has proposed a protocol of test methods for cement-based solidified wastes. The suggested test methods examine partitioning of contaminants as a result of their chemical speciation, and potential for slow release of contaminants, based on the mobility of the contaminants in the solidified waste matrix, and the durability of the matrix. Most of the suggested tests are standards from the fields of hazardous and radioactive wastes, some of which have been evaluated in a cooperative study with vendors of solidification processes, initiated by Environment Canada. Based on the performance of a solidified product in the tests, it is considered for four utilization and disposal scenarios unrestricted utilization, controlled utilization, segregated landfill and sanitary landfill. The protocol represents a first attempt to develop a management tool for solidified wastes that accounts for their physical and leaching characteristics, in the context of different disposal scenarios.