Photo Fenton Oxidation Replaces Fenton Oxidation: Less Sludge and Lower Cost of Ownership!

For waste waters with a special constitution we apply Photo-Fenton-type reactions to achieve the best overall performance. Our specially designed process combines a low chemical consumption with a high degradation rate.

The advantages of the Photo-Fenton compared to the Fenton process are significantly lower operating costs, the absence of the filter press(es) and a much higher degradation rate of the Photo-Fento oxidation compared to the Fenton oxidation. Furthermore, the Photo-Fenton process can be largely automatic, unlike a Fenton process, which will always remain highly manual, as even an "automatic" filter press always requires a lot of manual intervention - the difference between theory and practice. Furthermore, a Fenton plant is getting silted up over time and maintenance is increasing significantly to keep it operational.

Wherever recalcitrant organic systems and even aromatic structures are present, photo-Fenton has gigantic advantages, since photo-oxidation quickly and effectively breaks down organic compounds and makes them more readily accessible to further oxidation.

Table: Comparison of Fenton and Foto-Fenton


Fe(2+)+H2O2 --> Fe(3+) + 1 OH-Radical + 1 OH-

Partially organic is sorbed on the FeOOH sludge (separate disposal)

H2O2 + UV --> 2 OH-Radicals

Further degradation reactions due to photolysis
Further degradation reactions by intermolecular electron transfer reactions

Formation of reactive species1 radical per H2O2
Double H2O2 consumption in comparison to UV / H2O2 (at the same degree of degradation)

2 radicals per H2O2
Additional reaction by charge transfer reactions in the photo-Fenton

Treatment efficiency

Usually limited to max. 65%,
caused by process and formation of sludge

Generally not limited by the chemsitry of the oxidation process, but in some cases extreme degradation rates not economic

AdvantagesSimple installation

Strong performance
High degradation rate
No increase of salt load
No additional sludge


Formation of sludge
Separation of sludge causes Additional OPEX and CAPEX
Huge increase of salt load
Unit requires high maintenance after some time of use
Handling and disposal of sludge from Fe-addition

Typically sligtly higher CAPEX

Automatic Fenton is not simple to realize, especially automatic sludge separation and handling

Foto-Fenton is easy to automate

Further information of Foto-Fenton.