Morten Sielemann
Modeling pH in Natural Waters JCE
Morten Sielemann
Niels Peder Raj Andersen
Kristian Keiding
Modelling the pH variation in rivers is an interesting exercise, not only from an environmental point of view, but also because it makes use of basic physical, chemical, biological and numerical principles obtained through undergraduate courses. The pH model is built systematically using theory and logical assumptions to include or exclude different parameters and processes. After that, a short discussion will show how the initialisation values were found. The final model will show how equilibrium problems can be solved in discreet steps for a dynamic system using the simple assumption, that equilibrium reactions are much faster than transport phenomena and biological transformation. Furthermore, the model will be used to predict the behaviour of pH when changing temperature, ionic strength, buffer capacity and biological transformation rates.