Modeling Volatile Organics in the Delaware Estuary

Abstract

A study is conducted to test whether calibrated tidal transport models linked to chemical process submodels can be applied to aquatic pollution problems using literature values for chemical properties. The chemical transport and fate model TOXIWASP is linked with the hydrodynamic model DYNHYD to calculate the upstream migration of seven volatile organic chemicals from a waste water effluent to a drinking water treatment plant in Philadelphia, Pennsylvania. Four steps of data acquisition and simulation are described: (1) Hydrodynamics; (2) mass transport; (3) sediment transport; and (4) chemical transport and transformation. Graphs and statistics indicate good agreement between simulation results and observed concentrations. Medians are predicted within factors of 1 to 4 for the different chemicals. Confidence intervals about the predictions generally envelop observed ranges. Effluent concentration estimates provide the largest source of uncertainty. Existing transport models may be adequate, but could be improved with refinement and recalibration. Volatilization kinetics are handled well enough.