Disposal, uses and treatments of combustion ashes: a review

As processes for high efficiency immobilization and forced extraction of metals and other elements cannot be evaluated well as to their long-term actual performance in the field by current leachability tests, it is presently not possible to settle the question of which process is preferable to reduce leaching. Moreover, the overall evaluation of destruction, immobilization and forced extraction is dependent on the weighting factors regarding respective environmental impacts.