Direct Photolysis

Besides initiating reactions via OH-radicals (generated from H2O2) the direct photolysis of water ingredients by UV irradiation plays a major role. However, sufficient absorption of these substances is required, which then can be selectively destroyed under proper process conditions. Especially the possibility of a selective oxidation of toxic ingredients is a major advantage in regards to efficiency and economics. 

Examples for direct photolysis of contaminants or pollutants:
EDTA (Ethylendiamintetraacetic acid)

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 the EDTA can also be completely mineralized.

DMSO (Dimethyl Sulfoxide)
   

NDMA (N-Nitrosodimethylamine)
   

DMSO and NDMA will be directly destroyed under UV-irradiation and further oxidized through subsequent reactions.