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Show Municipal Waste. Oxides of nitrogen fonned from MSW and RDF combustion rely upon food waste, yard waste, and some plastics as the source of nitrogen [51]. The nitrogen in these components is readily volatilized, and rarely remains in the char. Based upon the data in the EPA waste combustion data base [36] plus data from the Westchester, N.Y. facility [64], typical fuel nitrogen conversions for MSW are on the order of 11.6 percent. Wide variation occurs, however, with the range of apparent conversions being from 5% nitrogen conversion to 19 percent nitrogen conversion. This range of results is likely caused by the variability of MSW on any given day, or hour of the day. or season of the year, or region of the country. The 1l.6 percent, or 12 percent conversion rate is considered the best approach to NO. estimation given a lack of instantaneous data on fuel composition. . 3.5. Polyaromatic Hydrocarbons, Dioxins, and Furans The fmal constituents to be evaluated are PAH's, dioxins, and furans - the large molecule organic emissions from the combustion of low grade fuels in industrial boilers. These emission estimates are of particular imponance to risk assessment professionals attempting to permit facilities. Polyaromatic Hydrocarbons. PAH results were obtained from source test data as previously referenced. Analytical results from extensive tests of wood combustion [7] were analyzed, however no significant correlations were obtained. The most defmitive analytical results from the testing of MSW combustion were related to total PAH's, PCB's, and chlorinated hydrocarbons [33]. While regression equations were derived in the Lavalin study [331, they related to design parameters not included in this model (i.e. secondary air front/rear distribution ratio). Consequently, mathematical averages of emissions from source tests conducted under good combustion conditions were employed to estimate PAH concentrations. . Dioxins and Furans. Models for describing the mechanisms associated with dioxin and furan emissions abound. Analyses begin with the work of Bumb and co-workers, Trace Chemistries of FlTe [9]. More recent analyses include the analyses of Altwicker et. ale [1], Banon et. ale [3], Hagenmaier [21], Hasselriis [23], Seeker, Lanier, and Heap [45], Shaub and Tsang [49], and Tsang [58]. The kinetics of dioxin destruction, should the compound be formed, are amply discussed by Scrivner [44]. There appears to be agreement forming about the work of Banon, Hagenmaier, Seeker and others; that dioxin and furan emission formation is promoted by the presence of flyash, particularly in the temperature region of about 600 - 1000 -F. It requires formation of dioxin molecules, potentially from precursor aromatics, and the presence of significant quantities of excess chlorine. Once formed, dioxins are readily destroyed in less than 1 sec. at 1800 Of, however the destruction cwve is dramatically steep. Numerous individual source tests and data bases were analyzed to determine a method for estimating dioxin and furan emissions. Source tests on individual facilities iDcluded Quebec City [33] and Westchester, N.Y. [64]. Data bases of imponance included the work of Beychok [5, 6], California Air Resources Board [10], Keating and co-workers [30], and Midwest Research Institute [36]. 13 |