The VertiKKA project, presented by Kohlhepp, enables the treatment of grey water in combination with facade greening and photovoltaic elements. David Gaeckle presents the MeSRa research project, which is investigating a membrane bioreactor for greywater treatment in a new residential area with 2,000 inhabitants. Gregor Biastoch explains the experience gained from the TRAPA-India project on transition management for wastewater systems in India. We would like to thank Dr. Krishnakumar from NIIST for the invitation and the opportunity to contribute to the content.