The AOPs altered the structure and composition of the organic
compounds in the secondary effluent which was verified by the
LC-OCD chromatograms. The average apparent molecular weight
of the organic matter in the treated effluent was decreased as
lower MW organic compounds were formed during the treatments.
The concentration of humic substances in the treated water was
substantially reduced (by 65–80%), accompanied by increasing concentration
of LMW compounds which were removed on further
irradiation. The LMW compounds have been identified previously
as carboxylic acids and carbonyl compounds [32,36,37].