The decomposition of EDTA was studied in a pilot-plant flow-through system simulating an alkaline (pH 10–11) hydrogen peroxide bleaching environment. Results obtained by gas chromatography were compared with calculated concentrations and the percentage of the residual was calculated on this basis. The amount of hydrogen peroxide decomposition was evaluated and the chelate distribution calculated. The results revealed that, under the conditions investigated, the residual averaged 94%, with lowest value 79%. An average of 26% hydrogen peroxide was decomposed during the experiments.