Hazardous waste management requires an understanding of the processes which generate the wastes, a knowledge of toxicology and personnel safety, and application of state-of-the-art technology. This technology may take the form of totally new systems or the application of old methods and materials in new ways. It is to the latter that this paper is directed.
In this case, a number of waste impoundments (basins) which were decommissioned about ten years ago were being approached by rising ground water. Site remediation was deemed necessary to avoid ground water contamination. The remediation involved (1) excavation of the basins down to clean soil; (2) buildup of the basin bottoms to prevent future ground water contact; (3) processing (stabilizing) the wastes; and (4) replacement, final capping, and closure of the site.
This paper relates primarily to the processing of the wastes. Lime-based stabilization was employed to achieve pozzolanic microencapsulation. This paper describes the stabilization technique and the different types of lime used, and presents actual data on the leachate qualities of the waste materials using ASTM analysis methods, both before and after stabilization. Actual methods of carrying out the stabilization and the equipment required to do so are explained. The overall project requirements, process specifications, quality control methods, and closing plans are discussed.