Characterization and predicting DOM treatability by enhanced coagulation

The dissolved organic matter (DOM) plays significant role in water safety due to not only the natural occurrence but also man-induced pollution. To characterize and predict DOM treatability becomes therefore a very important and hot topic. In this paper, enhanced coagulation by four typical coagulants (FeCl3, Al2(SO4)3, polyaluminum chloride (PAC) and high performance polyaluminum chloride (HPAC)) without pH control was characterized using the chemical fractionation (resin adsorption, RA) and physical fractionation (high performance size exclusion chromatography (HPSEC) combined with peak fitting technique). Two sets of models of DOM treatability, i.e. removal efficiency, by enhanced coagulation of the four coagulants were developed by combining the chemical and physical DOM fractions based on the quantitative analysis of the removal of chemical and physical fractions of raw water. The two sets of models could be transformed to each other. The composition of the removable DOM by enhanced coagulation of the four coagulants was revealed by the two sets of models from two angles of view. The established models were validated using 29 raw waters (in thirteen Chinese drinking source waters in three seasons), and as a result the low deviation indicated that the predicted data matched well with the actual data. It provided the possibility for the application of the models in practical operation of drinking water treatment plant.