Resource flow characterisation and sustainable value creation analysis for the holistic circularity assessment of wastewater systems

Abstract The water sector is at the forefront of the circular economy transition due to the direct reliance industry and society has on clean water supply and adequate wastewater management. The circular use of wastewater has attracted significant attention in recent years, however, there is a lack of universal definitions and measurement tools required to achieve the circular economy’s full potential. The proposed methodology overcomes prominent problems for the circularity assessment of wastewater treatment processes. The resource classification framework developed facilitates robust indicator calculation for comparative assessments. Combining three indicator typologies, namely resource flow, action, and sustainability indicators, enables a normative circularity assessment, that uses value propositions to identify circular actions for the systematic investigation of the impacts to sustainable value creation. The assessment is exhibited by applying it to a case study, comparing conventional and novel photobioreactor wastewater treatment technologies. Resource flow indicator results highlighted improved outflow circularity, renewable energy usage, and economic performance of the photobioreactor system. Action indicators revealed that the photobioreactor technology was successful at achieving the defined value creating goals. Lastly, sustainability indicators enabled the direct quantification of environmental, economic, and social value creation, confirming that stakeholder benefits result from the photobioreactor wastewater treatment technology.