A safe, practical and economically feasible alternative to current waste management practices for low-level radioactive and toxic industrial wastes is required in today's environmentally conscious society. Solution Cavern Disposal (SCD) in caverns either purpose created or dissolved for a previous use, represents a positive engineering approach to disposal which addresses the issue of environmental security over geologic time. Because SCD is intended to be permanent, ensuring long-term isolation of waste slurry mixtures from the' biosphere is the most important aspect of this technology. Waste isolation can be achieved, in part, by choosing appropriate disposal sites, and by properly engineering a waste slurry which will compact over time when subjected to the stresses of a closing cavern.
The article will discuss our approach to SCD using engineered waste slurries designed to address the toxicity level o candidate waste materials. As well, issues related to site selection criteria, site investigation techniques, and decommissioning strategies will also be discussed Finally, experimental results showing how porosity reduction occurs in compacting slurries will also be presented.
There exists a increasing need in society for economic waste management methods to permanently dispose of various types of industrial wastes including non-toxic, toxic, and low-level radioactive. These wastes may be in the form of a liquid, a solid, or mixtures thereof Some industrial wastes can be easily cleaned, others are more reasonably recycled. However, there remain significant volumes of liquid and engineered wastes which do not degrade, cannot be recycled, and which are not totally non-toxic, for which permanent means of disposal must be used.
A short list of desirable characteristics of an ideal waste disposal approach for these wastes would include:
The waste disposal site must have an extremely small probability of interacting negatively with the biosphere;
The waste disposal technology should be relatively straightforward, economic, and flexible in its capacity to handle the waste materials;
Any waste management approach for permanent disposal must carry society's acceptance; acceptance only comes through clear understanding ofall process aspects;
The procedures for transporting, handling, and disposal of the wastes must be safe, meeting requirements of occupational health and safety agencies as well as the concerns ofimpacted communities;
The disposal sites must be permanent, should not impair current and future surface land use, and must not require permanent post-maintenance or treatments for any significant period (eg: > 10 years); and,
The price of the disposal method must allow it to operate economically.
As mentioned, there are different types of wastes for which different procedures must be developed. Although they are a vital aspect of overall waste management planning, the categories of toxic and non-toxic liquid wastes, and low-level radioactive wastes will not be treated in this article. This article will address only the technical and regulatory aspects of the disposal of non-toxic and toxic engineered wastes.
Furthermore, we limit disposal to those engineered wastes which are of low solubility in saturated brine.