Characteristics of fine processed construction and demolition waste in Japan and method to obtain fines having low gypsum component and wood contents

A method to obtain processed residue from mixed construction and demolition waste (mixed C&D-W) — free from environmental pollutants — for deposition in landfill is discussed. In particular, additional sieving, the presence of gypsum board in mixed C&D-W at the first stage of manual presorting, and the color of processed residue were studied for the basic characterization of the different fractions. Considerable precautions should be taken to prevent leaching of hazardous substances, such as T-Hg, Pb, Cr6+, As, and fluoride and its compounds, when processed residue, particularly in crushed fraction at an intermediate treatment facility, is used as construction material. A relatively high content of gypsum was noted in processed residue generated at demolition work compared to that generated at construction work in processed residue from mixed C&D-W in which the presence of gypsum board was observed at the first stage of manual presorting, and in white processed residue. Additional sieving for removal was ...