COMPREHENSIVE PROCESS DESIGN BY INTEGRATION OF VERSATILE REFINED STOICHIOMETRIC MODEL WITH “PLUG-IN” KINETIC MODULES

Wastewater treatment process models, as they have evolved in recent years, may broadly be classified as stoichiometric models and kinetic models. Stoichiometric models are typically simple tools that primarily maintain an inventory of flow and pollutant quantities entering and leaving individual unit processes and describe process transformations mainly in terms of empirical stoichiometric parameters. The models must also quantitatively account for effects of process and non-process recycles within the facility. The simple platform, however, limits the capability of the stoichiometric models to adequately describe the complex kinetics of physical-chemical and/or biological transformations that occur within each unit process. Sophisticated kinetic models are available that provide modules for accurate, rigorous simulation of individual unit processes, but are cumbersome and inefficient for use in tracking facility-wide mass balances. This paper describes a new modeling technique that combines the simplicity and comprehensive mass balance capability of a spreadsheet based “refined stoichiometric” model developed by CH2M HILL (Pro2D) with the accuracy of a sophisticated kinetic model (GPS-X by Hydromantis). The use of this technique in facilitating comprehensive facility process design is demonstrated. The demonstration shows how rigorous mass balance including recycles and rigorous process kinetics can be simultaneously accomplished and automated through the use of Dynamic Data Exchange (DDE) capability.