Post-treatment of treated wastewater using oxidation methods

The PILOTOX research project was conducted to prove that ozonisation is a suitable and inexpensive measure for removing pharmaceutical residues from the clear water and at the same time for disinfecting the water.

The PILOTOX research project (pilot investigations into the combined oxidative-biological treatment of wastewater treatment plant effluent for the removal of organic trace elements and active ingredients and for disinfection) was carried out in order to reduce the impact from the discharge of previously treated wastewater into rivers and lakes. For this purpose, the Technical University of Berlin in cooperation with Berliner Wasserbetriebe conducted trials at the Ruhleben wastewater treatment plant on the ozonisation of the clear water using a pilot plant from Wedeco on behalf of the Kompetenzzentrum Wasser Berlin gGmbH.

The results show that ozonisation is a suitable method for oxidative removal or transformation of the majority of the pharmaceutical residues found in the clear water from the Ruhleben wastewater treatment plant and at the same time for achieving a disinfection of the water. For a few parameters, germs were again found, but this was of no significance after mixing the ozonated clear water with Spree water, as the mixed water showed no exceeding of the EU Bathing Water Directive. An examination using various tests into the acute and chronic toxicity, into genotoxicity and into the endocrinal effect of the water showed that no ecotoxicological hazard potential could be ascertained in the oxidatively treated water samples in comparison with the untreated clear water. A calculation of the specific processing costs for a large-scale use of the ozone treatment process shows a cost range of 1.0 cent/m³ to 2.2 cent/m³.