Influence of oxidation of dissolved organic matter (DOM) on subsequent water treatment processes

The influence of oxidation processes on dissolved organic matter (DOM) with respect to its flocculation properties and its biodegradability was investigated. In the experiments, DOM samples of a brown water lake and of commercially available lignin sulfonic acids were used. Ozonation treatment, hydrogen peroxide (H2O2) in combination with UV irradiation, and UV irradiation only were applied in the oxidation of the DOM samples. The impact of the oxidation on the DOM was characterized by size exclusion chromatography, UV absorbance, and fluorescence spectroscopy. In order to investigate the flocculation properties of the DOM before and after oxidation, sedimentation field-flow fractionation experiments were performed. The biodegradability was probed in a biofilm reactor. Due to the oxidation, the biodegradability and flocculation was changed depending on the process applied and the degree of oxidation of the DOM.