Abstract
Among the industrial wastes, construction and demolition (C & D) wastes have been discharged in the range of about 70 million - 80 million tons/year in the past several years. Although the separation of C & D wastes has been progressed and their recycling rate has been increased since the Law for the Recycling of Construction Materials was enforced, reexamination of the meaning of these activities has not been performed yet from a viewpoint of chemical substances. In the present condition, it is difficult to control chemical substances at the construction and demolition sites. Under these conditions, the possibility of removal of hazardous chemical substances and organic contaminants at crushing and sorting facilities were investigated by using the sorted wastes from C & D wastes. The C & D wastes of 5.475 million tons/year were flowed into Saitama Prefecture in the fiscal year 2000. It was almost discharged from Saitama (56.6%) and Tokyo (36.5%). 99.3% of these wastes were processed at the intermediate treatment facilities. Especially, 67% of the amount was processed at the crushing and sorting facilities. Various kinds of chemical substances were analyzed about waste woods, waste gypsum boards, and mixed wastes which were taken from these crushing and sorting facilities. Separation of hazardous chemical substances was done successfully by dividing the waste woods into square lumbers and plates at the crushing and sorting facilities. It was also clarified that a lot of chemical substances gathered to the wood-chips for fuel or the dusts. In crushing and sorting of waste gypsum boards, the concentration of organic contaminants became high by mixing of papers. Since the degree of their contamination was high, it was required to reduce the organic substances by incineration, etc. And it was shown that disposal in a controlled landfill site was appropriate for the fine granules and dusts which were the residues of sorting. However, the dusts have a high possibility to become harmful industrial wastes as Pb. The development of some reduction methods of Pb is required.
