Geologic requisites for successful underground waste management include: (1) porous and permeable reservoir rocks, in which the storage space may be caverns, intergranular pores, or fracture crevices; (2) impermeable seals to prevent escape of fluid wastes; (3) adequate understanding of hydrologic parameters, and planning to prevent undesirable migration of fluids; and (4) compatibility between waste materials and the reservoir rocks and their natural fluids.

Layered sedimentary rocks, rather than igneous or metamorphic rocks, provide the most suitable reservoir space, for both geologic and hydrologic reasons, but they must lie below, and be well shielded from, fresh groundwater aquifers. If wastes are hazardous to the biosphere, objective reservoir zones must be located deep enough to provide permanent protection to groundwater aquifers.

The site must be reasonably stable and not actively moving along or broken by faults.

Choice of a suitable underground disposal site can be made only after a thorough investigation of available subsurface data, or by drilling and various other processes of subsurface exploration if sufficient data are not available. Preliminary investigations and later subsurface operations will be expensive but they cannot be avoided in locating new sites. Public insistence on an end to pollution must be accompanied by public understanding that a clean environment can be purchased only by higher taxes (if government managed) or by higher prices for consumer goods (if industry managed), plus individual cleanliness.

As waste-management costs rise, it will become more economical to convert wastes into usable products, in effect eliminating rather than managing wastes.

End_of_Article - Last_Page 2084------------