Is the wastewater sector failing circular economy test?

Wastewater treatment is undergoing a dramatic transformation as utilities move from traditional efficiency models toward the principles of the circular economy (CE). A new international review published in Water reveals that while progress is being made, the lack of standardized metrics is holding back full adoption.

The research titled “From Efficiency to Circularity in the Wastewater Sector: A Review of Performance Indicators in Regulated Countries” systematically analyzes hundreds of performance indicators to determine how countries are measuring, and failing to measure, circularity in wastewater management.

Based on the review of 83 articles published after 2020, the authors identified 386 unique Key Performance Indicators (KPIs) used to assess the transition from wastewater treatment plants (WWTPs) to Water Resource Recovery Facilities (WRRFs). Their findings highlight a critical gap: most existing KPIs focus narrowly on technical performance, leaving social and environmental aspects underrepresented.

Why are current wastewater metrics falling short?

The transition toward circular economy practices in wastewater management involves more than just operational efficiency. It requires integrated strategies to reduce, recover, reuse, and recycle resources within treatment systems. Yet the review found that the vast majority of KPIs used today do not capture the full spectrum of circularity.

Out of the 386 indicators analyzed, 134 targeted technical aspects such as energy efficiency and treatment capacity, while environmental (115) and social (43) dimensions lagged far behind. This imbalance limits the ability of utilities and regulators to evaluate the broader benefits of circular strategies.

The study also highlights the dominance of KPIs related to reduction (166) and recovery (137), reflecting the sector’s focus on cutting costs and extracting valuable resources like biogas and nutrients. In contrast, reuse (54) and recycle (29) indicators are far less developed, despite their potential to close resource loops and reduce environmental footprints.

Without comprehensive metrics, it is difficult to compare performance across countries, track progress over time, or identify best practices. This fragmented approach creates uncertainty for both utilities and policymakers seeking to advance sustainability goals.

What barriers are slowing the shift to circular wastewater practices?

The review identifies several obstacles preventing wastewater facilities from fully embracing circularity. One major challenge is the absence of a universal KPI framework. Regulatory agencies in Europe and beyond lack clear legal requirements for measuring CE performance, resulting in inconsistent reporting and assessment.

High implementation costs also deter progress. Upgrading WWTPs into Water Resource Recovery Facilities often requires significant investments in new technologies and processes. Without standardized evaluation criteria, utilities struggle to justify these costs or demonstrate their long-term value.

Experience gaps further complicate adoption. Large-scale CE practices remain relatively new, and many facilities lack the expertise to integrate advanced recovery and reuse technologies effectively. This knowledge gap is compounded by the fact that most research to date has prioritized technical efficiency, neglecting how social acceptance and environmental benefits should be measured.

The study also notes that existing policies, while supportive of circular economy principles, have yet to translate into practical regulatory frameworks. Aligning KPIs with the European Union’s Circular Economy Action Plan and the Urban Wastewater Treatment Directive is seen as a crucial step toward overcoming these barriers.

How can circularity in wastewater be measured more effectively?

To accelerate the transition, the authors call for the development of a standardized, globally applicable KPI framework that balances technical, environmental, economic, and social dimensions. Such a system would enable meaningful comparisons between utilities, support evidence-based policymaking, and drive investments in sustainable technologies.

The research recommends integrating the 4R strategies, reduce, recover, reuse, and recycle, into the design of new performance indicators. By doing so, utilities can move beyond cost-cutting measures to embrace broader sustainability goals, including resource recovery, greenhouse gas reduction, and community engagement.

Another key recommendation is to strengthen the link between policy and practice. Regulators should embed circularity metrics into legal frameworks, ensuring that utilities have clear targets and accountability measures. This alignment would also support compliance with international sustainability commitments.

Wastewater treatment plants have the potential to evolve into full-fledged Water Resource Recovery Facilities, turning waste streams into valuable resources. However, achieving this transformation requires more than technology; it demands coherent metrics that capture the true value of circular practices, the study concludes.