Dynamic Modelling of Trace Contaminant Removal in a Municipal Sewage Treatment Plant

The variability of influent and effluent concentrations of trace contaminants at a full-scale municipal sewage treatment plant (STP) was measured by intensive sampling at two hour intervals for eight consecutive days. From these data, the technique of time series analysis was used to generate predictive models describing the process response. The data indicated that municipal STPs are capable of efficient trace contaminant removal and significantly attenuate the variability of these contaminants in the raw influent. Significant correlations were identified between influent characteristics and effluent concentrations for selected contaminants. For three metals and three trace contaminants, adequate time series models were developed. Such models are valuable tools for the development of strategies to control trace contaminants in discharges from municipal STPs.