Modelling disinfection by-products in contact tanks

Numerical modelling has been extensively used in the field of environmental engineering as an efficient method for predicting the fate of contaminants. For chlorine disinfection contact tanks, current numerical models predict the disinfection processes as well as first-order functions for chlorine demand. In recent years, the study of the formation of Disinfection By-Products (i.e. DBPs) in drinking water has been a cause for public concern. Since both chemical analyses and monitoring of DBPs are very expensive and not yet widely available, the establishment of an efficient numerical model has become a priori for the analysis of DBPs. This study includes a second-order kinetic representation for chlorine consumption in the disinfection processes and incorporates this representation in a numerical model to predict the formation of DBPs. The model has been refined to predict the chlorine demand in the disinfection process and the distribution of the main DBPs in contact tanks, including primarily total trihalomethanes (TTHMs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA).