Use of numerical modelling in the prediction of membrane scaling. Reaction between antiscalants and feedwater

Empirical equations and numerical modelling methods are used to predict the possibility of sediments precipitating on the membrane used during the reverse osmosis process. The use of empirical formulae allows approximations to be made of the trends which can exist on the surface of the membrane during the water treatment process, The use of numerical modelling enables more accurate forecasting to be made of precipitation phenomena because it takes into account the process parameters (pressure and temperature) and a detailed identification of the physicochemical properties of feedwater. The modelling of phenomena associated with the prediction of membrane scaling should also be carried out for water to which doses of selected antiscalants have been added. These products activate chemical reactions on the surface of the membrane giving rise to new, different mineral forms causing a decrease in membrane effectiveness. In this paper, the results of comprehensive research and analysis carried out on selected waters are presented. They include forecasting by the use of empirical formulae and thermodynamic models. The results of these predictions were verified on the basis of actual laboratory tests and microscope-based studies of sediments secondarily produced on the reverse osmosis membranes. The research results demonstrate the existence of reactions determined by the physicochemical properties of the antiscalants and the water subjected to a water treatment process.