1. Urban Water and Waste Management, University of Duisburg‐Essen Essen Germany
2. Emschergenossenschaft und Lippeverband Essen Nordrhein‐Westfalen Germany
3. Ruhr University Bochum Bochum Nordrhein‐Westfalen Germany
4. Urban Water and Waste Management University of Duisburg‐Essen Essen Germany