Abstract: To ensure sustainable development of urban areas，a relatively new and very relevant and economically viable concept of decentralised or semi-centralised systems is gaining increasing interest.Fraunhofer IGB undertook the project DEUS 21 funded by BMBF of Germany，and carried out demonstration study on concept of semi-centralised urban infrastructure systems in Knittlingen.Anaerobic membrane bioreactor（AnMBR） technology has been successfully used as key process in wastewater treatment.Plant operation showed that，effluent of wastewater treatment plant was characterized by a relatively low concentration of organic substances（COD），no particles，almost no pathogenic microorganisms，and a relatively high concentration of nutrients ammonium and phosphate.This kind of effluent could be reused for agriculture and green land irrigation.The semi-centralised concept is suited best for implementation in regions with warm climate and a demand for irrigation water，in which no wastewater treatment exists yet.This approach could lead to a system of almost closed cycles of water，nutrients and energy.