MUNICIPAL SOLID-WASTE INCINERATOR FLY-ASH FOR GEOTECHNICAL APPLICATIONS

Many highly urbanized cities are faced with the problem of disposal of municipal solid waste because of the scarcity of land available for l andfilling. One possible solution is the incineration of the municipal solid waste. After incineration, about 20% by weight of fly ash and o ther residues are produced. Investigations into the physical and engin eering properties of the fly ash derived from municipal solid-waste in cineration indicate that the material is a potential source of fill ma terial, with low compacted density and high strength. The fly ash rela tively free draining, with permeability of the same order of magnitude its coarse grained materials. The use of the fly ash as an admixture in the stabilization of a soft marine clay showed improved undrained s hear strengths and lower compressive properties. Leachate tests on the samples of fly ash initially indicated trace quantities of cadmium an d chromium in excess of the acceptable drinking-water limits. After le aching for 28 days, the concentrations fell below the drinking-water l imits. Lime and cement can be used to stabilize the fly ash. The conce ntrations of heavy metals in the leachates of lime and cement treated fly ash were nondetectable.