The ozonation treatment carried out in the framework of the LIFE STO3RE project manages to transform the unpleasant smell produced by pig slurry and excess sludge produced in the WWTPs into a characteristic smell of wet straw. Ozone, by means of the partial oxidation of organic matter, increases the production of biogas, reduces the concentration of micropollutants, removes pathogens and, in addition, significantly improves the olfactory perception.

This fact shows that the incorporation of an ozonation treatment, in a process subsequent to anaerobic digestion, significantly increases the value of the high quality biofertilizer obtained by the LIFE STO3RE plant.