| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method by which an operation rate and a scale of a sludge dehydration equipment can be reduced, an amount of use of chemical such as alkali metal carbonate, a coagulant, a coagulant aid and a dehydration aid necessary for treatment of calcium included in incineration fly ash can be reduced, and maintenance work such as scale removal can be reduced, by reducing an amount of generation of inorganic sludge mainly composed of a calcium compound in leachate treatment equipment in a final disposal site.SOLUTION: In a method for landfill disposal of calcium-containing incineration fly ash in a final disposal site, a method of preventing calcium elution in the final disposal site comprises a preceding process of inhibiting elution of calcium before the incineration fly ash is brought into the final disposal site and a post-process of separating-removing the calcium in a leachate by addition of the alkali metal carbonate after being brought into the final disposal site. The preceding process includes a process of adding to the incineration fly ash, water and the alkali metal carbonate corresponding to 0.10-0.75 time of a theoretical equivalent of a carbonate ion of a formula (1) with respect to an eluted calcium ion from the incineration fly ash, and kneading the water and the alkali metal carbonate with the incineration fly ash, the formula (1):Ca+CO→CaCO, the sum total of an amount of use of an alkali metal carbonate in the preceding process and the post-process is the theoretical equivalent or less of the formula (1) with respect to the eluted calcium ion from the incineration fly ash.</p> |
