Treatment and Disposal of Incineration Residues

Over the last decades, increasing focus has been placed in several countries on waste incineration as an attractive method to reduce landfilling of biodegradable waste and utilize the energy content of the waste. In Europe, significant efforts have been directed toward best available techniques (BATs) for waste combustion, flue gas cleaning, and residue treatment. BAT implementation results in a continuing trend of further air emissions reductions, causing pollutants in the waste to be increasingly transferred to the various solid residues of the process, which constitute the main emission route from modern waste incinerators. Among waste incineration residues, bottom ashes are generated in the largest amounts at the same time possessing technical properties most suited for utilization. Other types of residues, including fly ash and air pollution control residues, although produced in lower amounts compared to bottom ash, are more problematic to manage due to their high content of leachable hazardous constituents. From a holistic point of view, incinerator ash processing and disposal should be optimized to attain the required level of environmental protection and gain the full benefits from utilization or sustainable landfilling. A prerequisite for ash utilization is that the highly polluted residues are not mixed with bottom ash; a similar criterion also appears to be recommended in view of landfilling, since the different types of residues display notably different properties which commonly require different disposal strategies.