In-situ Stabilization/Solidification of PCB (Polychlorinated Biphenyls)-Contaminated Soil

摘要

An evaluation was performed of the International Waste Technologies HWT-20 additive and the Geo-Con, Inc. deep-soil-mixing equipment for an in situ stabilization/solidification process and its applicability as an onsite treatment method for waste site cleanup. A demonstration was held at a General Electric Co. electric service shop in Hialeah, Florida which provided the bulk of the information for the technology evaluation. Conclusions were reached concerning the technology's suitability for use in cleanups of various contaminants and at different locations: immobilization of polychlorinated biphenyls (PCBs) appears likely, although due to low leachate concentrations for both the treated and untreated soils, a result of the low soil concentrations encountered in most of the tests, it cannot be confirmed; heavy metals can probably be immobilized; volatile organics can be reduced to low concentrations in treated soil leachates, but the ability to immobilize is not clear; a small volume increase on the order of magnitude of 5%-10% can be expected; the solidified material shows satisfactory physical properties, with high unconfined compressive strengths, moderately low permeabilities, and satisfactory integrity for the wet/dry samples, but unsatisfactory integrity for the freeze/thaw samples; and microstructural results indicate a dense, low-porosity, homogeneous mass, indicating a potential for long-term durability.