A comparision of regulated chemicals versus emitted PICs and PICs for risk analysis

摘要

In general, toxic combustion byproducts (TCBs) are the unwanted residues remaining in flue gases, combustion ashes, and wastewaters from the operation of an incineration or combustion facility. If a combustor is not well designed and operated, it may emit too high a level of TCBs. Categories of TCBs and some example constituents are as follows: 1. Acid gas: HCl, NO_x and SO_2; 2. Organics: Hydrocarbons such as dioxins and furans (PCDDs and PCDFs); 3. Particulates: Trace metals (conventional metals and radioactive metals) and soots; 4. Contaminants in ash; and 5. Contaminants in spent wastewater. Pollutants in Category (2) above are generally considered to be the products of incomplete combustion (PICs) in the field of hazardous waste incineration. TCBs has been one of the major technical and sociological issues surrounding the use of incineration as a waste treatment alternative. Because of the complexity and controversy, the U.S. EPA issued a draft "Combustion Strategy" on May 18, 1993. The objective of the "Combustion Strategy" was to address the needs of and to outline the approaches for upgrading the existing incineration standards to better control TCB emissions. This article lists those chemicals and metals which are regulated by two major U.S. environmental laws, namely, the Clean Air Act Amendments (CAAA) of 1990 and the Resource Conservation and Recovery Act (RCRA) of 1976. The CAAA is to regulate the air emissions from major sources, and the RCRA is to protect human health and the environment from the management of solid wastes, particularly from waste incineration. This paper also lists the PIC chemicals that were studied under U.S. EPA incineration research programs in the 1980s and the PIC chemicals that EPA permit writers are considering be the subject of risk analyses during the process of industry's applying for an incinerator operating permit.