The "Sino-German Special Seminar on Urban Water Environment System under Extreme Weather Conditions", jointly organized by Leibniz Universität Hannover and Tsinghua University, took place on November 29, 2022. Numerous experts and scientists from Germany and China intensively exchanged their views on the question of how cities and their water management infrastructures can be adapted or further developed, especially with regard to climate change and the resulting increase in extreme weather events. In 2021, heavy flooding as a result of heavy rain in Germany led to massive flooding in North Rhine-Westphalia and Rhineland-Palatinate, resulting in 180 fatalities. In the same year, around 300 people lost their lives in the Chinese city Zhengzhou after heavy rainfall. But extreme periods of drought and heat also place a heavy burden on people and often lead to high casualty figures. Most recently, there was a historic summer of drought and heat in both Europe and China in 2022. The pictures of the dried-up Yangtze River went around the world. These phenomena demonstrate the dramatic nature of climatic developments and require swift answers as to how we want to counter such extreme weather events in the future, which will continue to increase in frequency and intensity.
The seminar was opened by the Vice President International Affairs and Sustainability of Leibniz University Prof. von Haaren and by her colleague Prof. Peixue Jiang, Vice President of Tsinghua University. A total of 7 hours of intensive exchange followed. In terms of content, both the legal framework and innovations in the field of water treatment technology as well as urban water infrastructures were addressed. And this is not only about too much or too little water in the city, but also about which pollutants are present in the water and how we can especially incorporate rainwater and wastewater into the urban water supply (e.g. for the irrigation of green spaces). During the seminar, many similarities were identified but also the country-specific differences were clearly worked out. And this is where such a bilateral exchange is of particular value, as the partner perspective brings in questions not yet asked, new ideas and impulses, so that even new paths for tackling the challenges in urban water management that exist worldwide are emerging.
To name a few highlights: Numerous impulses were given on how urban sewer systems can be further developed so that sufficient stormwater can be stored, treated and used in the city. Innovative wastewater treatment processes were also presented that increase the efficiency of wastewater treatment and, at the same time, treat the wastewater through "Advanced Oxidation Processes" so that it can be reused, for example, to irrigate vegetable crops. And how can Artificial Intelligence and digitalization help to further improve the operation and maintenance of urban water infrastructures, or even lead them to performance improvements? Last but not least, the focus was on the design of urban ecosystems, but also very specifically on wastewater-related pollutants problems such as microplastics. In addition, COVID monitoring in wastewater and the methods used here for both countries were presented. The great interest on both sides regarding these topics is shown by the fact that the event, which was streamed on several online services, had up to 15,000 listeners.