Melting and stone production using MSW incinerated ash

Most of the municipal solid waste (MSW) in Japan is incinerated and the gen erated ash is landfilled. However, environmental pollution problems have in creased and Japan has decreased final disposal sites for landfills. With th e application of a melting system, the volume of incinerated ash can be red uced and the effective use of melted slag is being developed for use in civ il engineering works. However, the low strength of melted slag as a vitreou s structure has limited its effective use. As a solution for this deficienc y, a technology to crystallize melted slag into higher strength produced st ones was developed. With the joint cooperation of Chiba Prefecture and Kama gaya City, a demonstration plant for melting and stone production with a ca pacity of 4.8 tons of incinerator ash per day was constructed. The demonstr ation test was conducted from May 1998 to June 1999 with satisfactory resul ts stated below. Long-term stable operation and performance of the plant ha ve been confirmed and effective applications of produced stones have been d emonstrated on a commercial scale. The results are as follows. 1. A stable, continuous operation and good quality produced stones have bee n confirmed by treating more than 750 tons of MSW incinerated ash. 2. More than 99.9% of dioxins contained in the incinerated ash were decompo sed, and the concentration of dioxins in produced stones were less than the detection limit set by Japanese environmental standards. 3. Leaching values of hazardous heavy metals of produced stones sufficientl y met the environmental standard on soil pollution of the Environment Agenc y with superior leaching behavior for the Vitreous slag, thus confirming th eir safe applications. 4. The effective application of produced stones for aggregate was tested ba sed on Japanese Industrial Standards and every figure of test results met t he Japanese standard values. The use of produced stones as raw materials fo r permeable pavement blocks has been confirmed in commercial construction f or a park in Chiba Prefecture. Asphalt use was also demonstrated by paving a commercial roadway in Kamagaya City. (C) 2001 Elsevier Science Ltd. All r ights reserved.