About 400 participants from science and practice met in the “Grand Hall” of the World Heritage site Zeche Zollverein in Essen. The motto of the event was “Closing the water cycle”, and Prof. Jardin pointed out that sustainable and integrated solutions for water management had never been more important than today.

Connection between conference topics and venue

IWA President Tom Mollenkopf and Jonathan Clement, co-chair of the program committee, commented on the characteristics of the conference venue. Mollenkopf emphasized the role of coal mining and steel industry of the industrial development of Europe, the importance of the EU as strong force for collaboration, freedom and technological development. He warned against tendencies of “anti-intellectualism” and called scientists and politicians worldwide to collaborate in order to furthermore trust science- and fact-based solutions and bring them into public discussions.

Jonathan Clement said it was time to have the LET in Germany, and it could not be better than in Essen. He announced that the attendees were going to learn about technological approaches that are really new for the water sector. These were given in 60 lectures and around 150 poster presentations. They focus on the key topics of water reuse, removing trace substances from wastewater, closing material cycles, digital twins and cyber security as well as reducing greenhouse gases.

Perspectives of the German water sector

In their welcome adress, Dr. Lisa Broß, managing director of DWA, and Dr. Wolf Merkel, executive director of the water division of DVGW, took the occasion to present the Roadmap 2030. This is the action agenda for the future of water management in Germany, developed to combat with climate-induced changes of the boundary conditions for water supply and wastewater treatment in Germany. It is based on three research pillars: extreme water, smart water and sustainable water.

Is the new UWWTD a driver for innovation and technology development?

In a panel discussion, Gari Villa-Landa Sokolova, Eureau, asked seven water experts to give their opinions, whether the new EU Urban Wastewater Treatment Directive (UWWTD) will trigger technological developments and how. As an introduction, Miriam Haritz from the German Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection, outlined the main aspects of the new directive, which is expected to be released in October 2024. From the ministry’s perspective, this regulation goes far beyond the content of the former regulation. In detail, Miriam Haritz emphazised the 4th treatment step for eliminating micropollutants that will become mandatory of treatment plants of a certain size, the integration of the extended polluter responsibility (ERP), stricter limits for N- and P-concentrations in the effluents and the mandatory of WWTP to become energy neutral by 2045. In all, Haritz named the new directive a holistic, cross-sectoral contribution to a resilient water management.

The panel`s expectations on this directive are high, but so are the challenges seen for its implementation. Tom Mollenkopf said the directive had the potential to revolutionize the water sector, however he also saw the devil in the detail. Wendy Francken, president of the European Water Association (EWA), expects the world outside Europe to look at the new directive and its effect. But she also wants to consider PFAS elimination. Additionally, she reminded to the need for both nature-based and technical solutions for stormwater management. As a representative of a utility, Morten Rebsdorf from Aarhus Vand in Denmark considered possible difficulties in the practical implementation of new treatment steps as well as in the monitoring of substances under consideration, like PFAS. According to Oliver Puckering, Innovation Manager at Xylem, there is the need for more research activities in this field, but also a need to understand the particular challenges in different European countries. And he warned against a „valley of death“ for new technologies, if data are not shared.

Bridging the gap between technology and policy

Miriam Haritz believes that bridging the gap between technological development and the policy field is a main challenge in implementing the new directive. According to Prof. Jörg Drewes, Technical University of Munich, the directive can be a game changer, depending on pioneers to step forward by building demonstration facilities. He sees a new role for research to be a companion of utilities in this process of implementation. On the question, how the requirement for energy neutrality can be fulfilled and whether we haved missed the opportunity to combine wastewater and energy sector, Morton Rebsdorf reminded to consider the system boundaries: how can WWTP sell energy and get rid of waste heat? And Natalie Páez, doctoral candiate at TUM and young water professional, looks at wastewater treatment plants as places to contribute to mitigating climate change. However, would be this happening fast enough? To her opinion the way of speeding processes up is collaboration.