Formation, release and control of dioxins in cement kilns coprocessing wastes

摘要

Co-processing and treatment of hazardous wastes in cement kilns have for decades been thought to cause increased emissions of PCDD/PCDFs - a perception that has been evaluated in this study. Hundreds of PCDD/PCDF measurements conducted by the cement industry and others in the last few years, on emissions and solid materials, as well as recent test burns with hazardous wastes in developing countries do not support this perception. Newer data have been compared with older literature data and shows that many emission factors have to be reconsidered. Early emission factors for cement kilns co-processing hazardous waste, which are still used in inventories, are shown to be too high compared with actual measurements. Less than ten years ago it was believed that the cement industry was the main contributor of PCDD/PCDFs to air; data collected in this study indicates however that the industry contributes with less than 1% of total emissions to air.