Along with initiating reactions via OH radicals (generated from H2O2) the direct photolysis of water ingredients by UV irradiation plays a major part. However, sufficient absorption of these substances is required, which can then selectively be destroyed under proper process conditions. Especially the possibility of a selective oxidation of toxic ingredients is a major advantage with respect to costs and efficiency.
This reaction initiates the transformation of the virtually non-biodegradable EDTA to the good biodegradable NTA, which is degradable in the biological phase of the sewage treatment plant.
With an additional oxidation cycle, the EDTA also becomes completely mineralizable.