Stockholm Royal Seaport

Sustainability Report

Completed Updated: 13/02/2024

Food and energy in a circular economy

Wastewater resources such as waste heat, organic matter and plant nutrients are recycled to some extent in conventional wastewater treatment plants – that is, at the end of the pipe. However, conventional systems present challenges, where plant nutrients and energy potential in particular are not fully utilised.

In order to spread knowledge internationally, this study was conducted to demonstrate the benefits of a source-separating wastewater system, one that separates toilet waste from other wastewater, thereby enabling better resource recovery from the waste water flows.

Purpose and goal

The purpose of the project was to review the potential of increased use of resources through source-separating wastewater systems.

Results and experiences

As part of the “Food and Energy in a Circular Economy” project, a study was conducted into the potential and scenarios for source-separating sewage systems in densely populated urban areas. The study shows that it is possible to significantly increase resource utilization and contribute to reduced climate impacts. This is done primarily through the recovery of waste heat at the property or district level, and by replacing commercial fertilizer with plant nutrients from wastewater. With the increased use of food waste grinders with separate collection of other waste, it is possible to significantly increase biogas recovery.

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