Dehydration of Decommissioning Gels for Waste Reduction

Abstract

One method of decontamination or capture of loose contaminants during the decommissioning process is the use of gels. Gels have some advantages over water based solutions in that spills are much easier to clean up while a water based solution may penetrate the concrete or soil and spread contaminants further. One disadvantage of gels is that they include other constituents that increase the overall waste volume. Thus, while they can do an excellent job of capturing and securing loose contaminants, they will increase the total volume shipped to a waste site for disposal. Regardless of the hydrocarbon compound used in the gel, there is usually also some water present. In this work, we examine two methods for the reduction of the gel volume by eliminating the water content. For gels that use water as part of their creation, this can result in waste mass reduction by greater than 80% and possible volume reduction greater than 85%. The first method assessed is natural evaporation processes and the second method assessed is a distillation process. The first process is much slower but is more reliable in ensuring that the water is evaporated from the gel leaving a dry puck for easy disposal. The second process is able to obtain higher volume reductions faster and is also able to breakdown some of the hydrocarbons releasing other non-contaminants however the second method is more challenging to ensure there is no carry-over of the waste product. The paper will discuss the nature of the gels tested, both techniques, and the volume reduction results obtained to date.