Some liquid toxic wastes (such as those containing metals with low organic contents arising from metal finishing and plating processes) can be treated with cement. The resulting slurry, often containing about 55% solids, is allowed to solidify and then disposed to a licensed landfill.
The process for disposal or long-term containment of wastes from nuclear power generation is a function of the degree of radioactivity involved. Intermediate and low-level waste is contained in steel drums, which are filled with a cement grout, based on selected Portland cement and ggbs. The drums can then be stored either in above-ground storage or in geologically stable underground repositories. High-level waste is stored above-ground is specially engineered cooling lagoons.
For further information see Containing and encapsulating waste, published in CONCRETE in January 2003, pp 49–50. Copies are available as a free download from the Members Area of the Concrete Society web site.