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The Relationship Between Chlorine in Waste Streams and Dioxin Emissions trom Wasta Combustor Sucks Cluster Analysis was used to analyze the PCDD/F signatures. Signatures were deemed differ- ' ant if the cluster coefficient was greater than that which the errors and uncertainty inherent in the PCDD/F sampling and analysis method explain at the 95% statistical confidence level. Quantity change assessment began by graphing the data to identify visible trends. This was followed by a variety of methods. Canonical correlation, ordinary least squares and lag-one autocorrelation linear regression and Principal Components Analysis [PCA) were used to iden- tify statistically significant relationships. Parameters like chlorine and temperature that might ' be contributing to observed concentration changes were evaluated using Analysis Of Variance [ANOVA]. Blocking variables that indicate the presence or absence of an effect (e.g., PVC plastics added or not) were used to account for incremental changes in operating parameters and configurations in the ANOVA. Continuous variables were used to account for continuous parameters like temperature and flue gas oxygen content. The statistical significance of each coefficient waz used to determine whether the associated variable caused a measurable effect. Findings ' The data assembled for this study come from the major types of waste combustors. Input chlorine concentrations range from 0.1% to over 76% (Figure 1) and having gaseous HCl con- centrations measured before the APCS from 20 to nearly 8,000 ppmdv @ 7% OZ (Figure 2). This range of chlorine concentrations and the differing nature of the PCDD/F congener distri- butions make it inappropriate to analyze these data as a complete set. Rather, the data were analyzed by combustor type. Municipal Waste Combustors [MWC]--Data from the 63 MWC facilities in the database were used in this portion of the study. Several of the facilities were subjected to parametric tests 1, that focused on PCDD/F formation. A number of spiking tests added mixed plastics, PVC (1 and salt to the normal feed to explicitly determine the relationship between PCDD/F concen- ~ tntions and chlorine. Finally, many tests included some measurement of chlorine feed rate. For spiking tests without measured uncontrolled HCl concentrations (i.e., HCl data before the acid gas control system), the variables representing step changes in feed composition were used to identify these intentional interventions in the analysis. Comparison of the individual signatures obtained from each facility found that some test runs apparently differ from the bulk of the test runs by more than nominal method imprecision. 4