The world is facing a water quality crisis in the form of water pollution and scarcity like it has never seen before. Discharges of untreated sewage wastewater flows into the natural watercourses constitute a menace to the environment. Academia and the scientific community have explored and proposed circular economy (CE) concepts aimed at mitigating the human footprint on natural resources and focusing on ensuring sustainable water management initiatives. Under this notion conventional wastewater treatment plants (CWWTP) are turning into water resource recovery facilities, which not only clean its wastewater but also recover the useful organic resources like energy and nutrients (phosphorus and nitrogen) that otherwise are destroyed or disposed back to the environment. However, research has also indicated that the implementation of these circular economy practices lacks a system’s thinking approach when it comes to understanding the importance of social issues, where the needs and rights of all social actors and local communities are adequately considered. Consequently, this study provides a methodological approach which through qualitative and quantitative methods that integrates the opinions and preferences of stakeholders at various stages of the project, enhances the robustness of its findings. From the empirical input of key stakeholders, relevant criteria were identified to assess the sustainability impact of nutrient recovery technical alternatives from urban wastewater treatment plants.
The evaluation conducted at the Las Esclusas CWWTP in Ecuador (used as a case study) highlights the significance of social considerations, particularly in the context of implementing nutrient recovery technologies in countries from the Global South. A preliminary technical assessment showed that three commercially nutrient recovery technologies could be feasible to be implemented at this plant (precipitation/crystallization of struvite and mono-incineration & AshDEC to recover phosphorus and ammonia stripping to recover nitrogen). However, none of these technologies can be immediately implemented under current conditions. Many aspects will need to change before the plant is ready to recover nutrients like adding a secondary treatment. Yet the input from stakeholders in assessing relevant criteria for the purpose of measuring the sustainability performance per nutrient recovery technology, was instrumental to underline the importance of social aspects and emphasize the essential role of the institutional landscape. Challenges within the institutional domain, characterized by inefficiencies in the legislative and political systems, pose significant obstacles to the implementation of nutrient recovery technologies. In the specific case of Las Esclusas CWWTP, the absence of robust environmental legislation and institutional commitment towards circular economy projects, diminishes the feasibility and perceived value of implementing nutrient recovery systems. Furthermore, cross-cutting issues such as bureaucratic inefficiencies and lack of institutional transparency further complicates the attempt to progress at a faster rate within the context of the application of circular economy initiatives to the sustainable management of wastewater. Without proactive government engagement and inter-institutional collaboration, the transition to circular practices in the wastewater sector remains unlikely in countries from the Global South. This inclusive approach emphasizes the importance of considering social perspectives in wastewater management practices which ultimately contributes to more responsible and socially relevant decision-making processes.