Evaluación de la preoxidación para remover carbono orgánico disuelto y disminuir la formación de trihalometanos en la potabilización

. Organic matter in drinking water can cause problems to the purification plants, such as changes in the water ́s organoleptic properties, an increase of the purification costs and increases in the disinfection byproducts.Objective. Evaluate pre-oxidation as an alternative to improve the removal of disolved organic carbón (DOC) and/or reduce the formation of trihalomethanes during the purification processes. Materials and methods. Experiments were carried out by means of a jar test in which the efficiency of two coagulants (aluminum hydroxychloride and aluminum sulphate) and two oxidation agents (Hydrogen peroxide and chlorine dioxide) to remove DOC and reduce trihalomethanes as a byproduct of the disinfection with sodium hypochlorite. Turbidity, color, pH and UV254 changes were also assessed. Results. In terms of DOC removal, there is a significant difference (p = 0,033) vetween the use of aluminum sulphate and aluminum oxychloride, and the latter is more efficient. Preoxidation improves the color removal and the turbidity, and only with hydrogen peroxide an increase in the DOC removal was proved. Conclusions. Preoxidation with H2O2 in purification processes is a feasible alternative to remove not humic and hjydrophilic organic matter. The trihalomethanes ́ values were not above those allowed in Colombia and USA, 200 μg/L and 80 μg/L, respectively.