New ozone treatment process at Egaa Wastewater Treatment Plant

There has been a significant change in the composition of the wastewater to the Egå Wastewater Treatment Plant (WWTP) due to the expansion of Aarhus University Hospital in Skejby. Pharma residues have been registered that are above the PNEC values in the discharge from the Egå WWTP following the expansion of the hospital. This has led Aarhus Municipality to conclude that additional treatment for pharma residues must be carried out at the WWTP. A 4th treatment step therefore has to be established at Egå WWTP to achieve sufficient removal of drug residues in the effluent. A screening of available treatment technologies and theoretical modelling has been carried out based on the 10 focus substances that can be measured in the effluent from Egå WWTP. From this, it is concluded that implementing an ozone treatment step in front of the existing sand filter will be enough to remove the remaining pharma residues.