Grey becomes blue: reducing drinking water use

Today, green spaces tend to be irrigated with drinking water during dry periods. An alternative source of irrigation could be treated greywater – water from baths, sinks, and laundry.

For Stockholm Royal Seaport, a source-separated sewage system is planned with separate collection and treatment of greywater from households and businesses. When the area is completed, approximately 1,000m³ of greywater will be generated daily. After treatment, this water could be used to replace drinking water for irrigation.

Additional applications for the treated greywater include dust suppression during street sweeping and concrete production at a nearby concrete plant. Greywater recycling is desirable for both Stockholm Vatten och Avfall and the City of Stockholm. Stockholm Vatten och Avfall has a corporate goal to be resource-positive by 2030, which includes circular operations. The City of Stockholm regards the opportunity to water green spaces in a more sustainable manner positively.

Purpose and goal

The project's purpose is to contribute to the reduced use of drinking water in Stockholm Royal Seaport in the short and long term. The project's goal is to prepare for the substitution of drinking water with treated greywater for irrigating green spaces and to investigate the potential for other uses.

Results and experiences

The project began in December 2022, and no information has been published yet.