Advanced treatment in full-scale wastewater treatment plants

In November 2023, an excursion was organised in the frame of the EMPEREST project in wastewater treatment plants (WWTPs) that have quartenary treatment for the removal of organic micropollutants. WWTP operators and other project partners participated in the excursion, and for most of them it was the first time they could see the advance technologies in action. The presentation of the technologies by the local experts and the unique opportunity to discuss with them about the design, daily operation, performance, troubleshooting, maintenance and, of course, financial issues, was extremely beneficial for the project partners. Two of the three technologies were tested in the EMPEREST project.

The first visit was to the Werdhölzli WWTP in Zurich, Switzerland, covering a catchment area of  482,000 population equivalents (PE). Daniel Rench, the plants' managing director, explained the reasons for choosing ozonation (the largest in Europe) and gave an insight into all relevant topics.

The next stop was at the Immendingen WWTP in Germany, which is located on the Danube River and covers about 25,000 PE. It was one of the first WWTP in Germany to use granular activated carbon (GAC) filtration  for the removal of micropollutants. Sebastian Platz, consultant at SWECO, participated in the planing of the GAC unit and was our host during the visit.

The final visit was to the Steinhäule WWTP in Ulm, Germany, which covers a catchment area of 440,000 PE. At this plant, the use of powdered activated carbon (PAC) with subsequent sand filtration was investigated in detail and led to the development of the 'Ulm process'. Christian Hiller, Department Manager, had been involved in the development of the technology and was the most suitable person to present the process.