From linear to circular water management : A case study of Sandön/Sandhamn

Sammanfattning: Even though water is essential for all living beings, the way humans manage water is traditionally linear; extract, use and dispose. By doing so, many cities have partly disconnected themselves from the environment by existing beyond the local hydrologic system. A circular water system, which reuse water within the technical water system, has the potential to improve the status of the environment and reduce pressure on existing water resources. As such it is an approach that receives increasing attention. This study aims to investigate how a circular water management approach can reduce fresh waterconsumption and decrease the human pressure on water resources through a case study of the island Sandön/Sandhamn in the Stockholm archipelago. A literature overview which identifies circular water management strategies have been performed along with a situation analysis of Sandön. To identify and assess different options of reuse the framework of strategic environmental assessment have been used. In the case of Sandön, which have a high water-demand peak during summer, decentralised solutions for one of the largest water consumers is recommended. Reclaiming water from the wastewater treatment plant to, among other, flush toilets would also be favourable. Private homeowners could also beneficially implement reuse by flushing toilets with water used to wash hands or from showers. The study shows that circular water management provides an opportunity to reduce pressure on water resources and use them in a more efficient manner. The most crucial criteria for circular water measures success is public acceptance. It is also important to thoroughly map local conditions to identify the best suitable reuse measures as each location is unique.