Municipal solid waste bottom residue

In 1980, 2.8 million tons of municipal solid waste was burned in the USA, yielding approximately 33% municipal waste combustion (MWC) ash. By 1990, the amount burned had increased to 32 million tons, creating approximately 25% of MWC ash or residue [265-267]. Controlled combustion of municipal solid waste produces two types of ash fly and bottom ash. Most MWC ash (80-99%) is bottom ash however, it usually contains a high percentage of toxic materials, and the leachates may not meet environmental standards. 

The aim of this chapter is to present a conceptual model of the leaching process in landfills based on two exemplary field studies at a municipal solid waste incinerator (MSWI) bottom ash landfill, Landfill Lostorf, and a lysimeter investigation, Landfill Teuftal, containing cement-stabilized MSWI air pollution control (APC) residues. 

Solid residues with final storage quality should have properties very similar to the Earths crust (natural sediments, rocks, ores, soil). This can be achieved in several ways, for example by assortment or thermal, chemical and biological treatment. In most cases, this standard is not attained by simple incineration of municipal solid waste - that is, by only the reduction of organic fractions. There is, in particular, the problem of easily soluble minerals such as sodium chloride. Future efforts should be aimed at optimizing the incineration process in a sense that critical components are concentrated in the filter ash and in the washing sludge, whereas the quality of the bottom ash is improved in such a way that deposition is facilitated and even reuse of this material is possible due to either the low concentrations or chemically inert bonding forms of metals. 

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