Prediction of the Potential for Odor Emissions from an Interceptor Sewer System Using a Mathematical Model with Limited Data Yields Useful Results

The potential for corrosion and odor emissions from a combined sewer interceptor system in Northwest Chicago was investigated. Seven manholes along the interceptor system were selected as monitoring locations, and eight critical physical-chemical and biological parameters were measured semiweekly at each location for four weeks during the morning and afternoon hours. Statistical analyses were performed to determine the diurnal variability of 5-day biochemical oxygen demand (${\mathrm{BOD}}_5$), as well as the variability of total sulfide with respect to ${\mathrm{BOD}}_5$ and the sewer flow rates. Subsequently, the Pomeroy–Parkhurst mathematical model was used to predict the change in total sulfide concentration in a mile-long segment of the interceptor system. The model was calibrated by modifying the sulfide flux coefficient in the generation term to reflect the conditions in these interceptors, such that the measured values and model predictions were in agreement. A strong linear relationship between the system’s wastewater flow and water quality characteristics and the modified sulfide flux coefficient was found (${\mathrm{R}}^2=0.828$). With limited wastewater characteristic data, the modified Pomeroy–Parkhurst model can be used in predicting the change in total sulfide concentrations for this interceptor.