What are the main conclusions from this information?
a) During ozonation of waste waters the generation of hydroxyl radicals takes place without
using additional steps. So you will always have a certain balance between direct ozone
reactions and radical reactions. Whether an additional enhancement by UV or H2O2 actually
provides advantages has to be proven separately.
b) In real waste water matrices it is difficult to determine the yield of generated hydroxyl
radicals. The UV/H2O2 process seems to be the combination with the highest yield. But, in
practice this consideration is only theoretical. This is due to the molar extinction coefficient,
different possible side reactions and maybe a restricted UV-transmission.
c) The best available method must be proven regarding waste water conditions and treatment
goals by taking actual cost into account. At the end of the day the treatment results in
relation to the cost are decisive.