OCR Text |
Show incinerated relatively significant concentrations of HCl were detected in the flue gases. This indicates that PVC is not the only source of HCl during the incineration of MSW. Also, several ~o8d burning experiments conducted by various researchers' have demonstrated that chlorinated aromatic hydrocarbons, PCDDs and PCDFs are produced without the addition of HCl, PVC or other chlorine sources. The objective of this paper is to test the hypothesis that a reduction in PCDD/PCDF emissions can be achieved by removing plastics, specifically PVC, from the solid waste stream. The approach involves an examination of the data available on the characterization of MSW, and a review and an analysis of PCDD/ PCDF emission data from actual incinerators. Chlorine Content of Municipal Solid wastes The sources of chlorine in typical municipal solid waste must be understood if one is to propose/implement the reduction of PCDD/PCDF emissions by lowering the chlorine content of the MSW. Numerous studies have reported on the composition and chlorine content of MSW. Not surprising, the results differ widely. However, all agree that the sources of chlorine are numerous, and removing one item, e.g., chlorinated-plastics, will not eliminate chlorine from the waste stream. An early study by Alter 9 of the relative content of chlorine in the various household components of MSW as percentage of the total is shown in Table 1. A municipal waste characterizf5ion program conducted in 1979 in Dearborn Heights, Michigan reported similar findings (Table 2). Clearly removing one component of the waste stream, e.g. plastics, or one specific item, e.g. PVC, will not eliminate chlorine from the waste. The most comprehensive study of the chlorine content of municipal solid waste was conducted by researchers at the National Bureau of Sirndards at two sites, Baltimore County, MD, and Brooklyn, NY . The total chlorine and water soluble chlorine contents of the components of the MSW were determined from sampling studies carried out for a five day period (Table 3). The total chlorine contents of the overall MSW samples at Baltimore County, and Brooklyn, are 0.45 and 0.89 mass % on a day basis, respectively. |