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.

This study applied a Community-Based Participatory Research (CBPR) approach to assess water-related challenges on San Cristóbal Island, Galápagos, Ecuador. Data was collected by means of semi-structured interviews (74 households), stakeholder interviews, expert consultations, and additional 150 questionnaires (150 residents) regarding water vulnerability and flood risk. This research assessed lived experiences alongside governance mechanisms, investment plans, and socio-economic status and highlights the individual responsibility and adaptability requirements by residents of San Cristóbal in regards to water scarcity, quality and floods.

The island’s gravity-led distribution network covers 93.07% of households but operates intermittently (3 hours/day), necessitating storage at the household level and shifting maintenance responsibilities to residents. As a result, vulnerabilities differ across and within neighbourhoods according to storage type, cleaning practices, chlorine use and geographic location, none of which show consistent correlation Spatial mapping of the system revealed pressure-sensitive segments, indicating uneven performance across the system, where pressure fluctuations compromise delivery. Moreover, limited contingency support has made neighbourhoods still awaiting connection to the main supply overly dependent on limited sources, leaving them particularly vulnerable during service interruptions.

Reported system failures are widespread: 89% of interviewed households reported at least one problem, most commonly water shortages, high turbidity, and pipe breakages. Vulnerability varies between households depending on the capacity of water reserves and the potential of (re-)contamination. Even for households that report a rigid cleaning regime, these problems are present. The multiple mentions of pipe leakages and muddy water indicate seepage into the pipeline system, suggesting that water quality is compromised before it reaches the households. However, according to soe residents, contamination stems from the source, citing low efficiency at the drinking water treatment plant. This distrust in water quality translates to a high reliance on bottled water, which is uniform across the island despite its associated costs.

Reports on flood-related incidents are highly dependent on location, concentrated in places where local topography, incomplete drainage, or ravine bottlenecks amplify runoff. Notably, 23% of all questionnaire respondents reported that their homes suffer damage from flooding, highlighting the tangible impact of these events on residents. Despite significant municipal spending on flood relief, the creation of predictive flood models is restricted by limited technical knowledge and know-how, causing the infrastructural interventions to remain largely reactive, with affected areas identified only post-event. Comparing municipal investment plans with a resident weighted satisfaction index reveals that spending does not uniformly translate into higher satisfaction. Residents report greater value to reliability and communication with the community. Spatial analysis of the urban area Puerto Baquerizo Moreno shows that socio-economic vulnerability generally increases from coastal to peripheral neighbourhoods, but incomplete infrastructure, water shortages, and flooding do not always coincide with limited municipal support, meaning that some vulnerable areas still benefit from interventions while others remain underserved.

The results highlight how infrastructure performance and governance practices interact to shape everyday water-related vulnerability for the residents of San Cristóbal. The CBPR framework allows for enhancement of urban planning knowledge, with lived experiences of those most affected by it.

Per- and polyfluoroalkyl substances (PFAS) have remained persistent environmental contaminants since the 1950s, despite ongoing efforts to curb their production and find alternatives. Most health studies have focused on Perfluorooctanoic acid (PFOA) and Perfluorooctane sulphonic acid (PFOS), leaving limited data on other PFAS compounds in water. The European Union, particularly the Netherlands, has implemented stringent measures to control PFAS in drinking water due to their uncertain health impacts on
humans. Recently, the Dutch Institute for Public Health and Environment (RIVM) proposed a new guideline of 4.4 ng PFOA equivalent (PEQ) per litre for PFAS in drinking water, a substantial reduction from the current European Drinking Water Directive standards of 100 ng/L for the sum of PFAS and 500 ng/L for total PFAS.

While improving drinking water quality is expected to have positive health outcomes, the advanced treatment technologies required to meet this new guideline can be harsh, potentially releasing emissions that may cause negative health effects. This research, centred on the Leiduin drinking water treatment plant operated by Waternet in the Netherlands, investigates whether the health benefits of the new guideline outweigh the potential harms caused by the treatment processes necessary to achieve it.

To explore this, the study first calculated the Disability-Adjusted Life Years (DALYs) lost due to PFAS exposure from drinking water at the current concentrations, exceeding the 4.4 ng PEQ/L guideline, using a literature review to link guidelines with PFAS health effects. The second step involved conducting a Life Cycle Assessment (LCA) of the treatment system at the Leiduin plant, focusing on the treatment steps necessary to meet the new guideline, and calculating the DALYs lost due to the environmental impact of achieving the 4.4 ng PEQ/L standard. These DALYs were then compared to assess whether adhering to the new guideline is justified in terms of health impacts.

The results indicate that the DALYs associated with the current and proposed guidelines fall within similar ranges, showing limited health benefits. Specifically, the health benefits (in DALYs) gained from implementing the new guideline range from 0.4 to 4 per year, while the DALYs lost due to the treatment technologies required at the Leiduin plant range from 1.55 to 3.25 per year for the population receiving drinking water from the Leiduin site, depending on the type of activated carbon used in the treatment process.

These findings suggest that the potential health benefits of stricter PFAS regulations in drinking water maybe counterbalanced by the negative health impacts of the treatment technologies required to achieve
these lower concentrations

With population increases, the traditional linear economy has become increasingly unsustainable creating environmental pressures such as climate change and resource scarcity. The Dutch government has set lofty goals to create a circular economy by 2050. The agricultural sector in the Netherlands is vulnerable to climate pressures but is also highly profitable at the cost of sustainability making circular models difficult to implement. The world's first Floating Farm in Rotterdam, NL was created to bring food production into urban areas to increase the resilience of food supply chains. The Floating Farm has worked to implement a more circular dairy farming model by reducing land use and using recycled feed.

In this study, the circularity performance of the Floating Farm (FF) dairy production process was quantified using an indicator-based circularity assessment method. Indicators were derived from the FF's self-proclaimed circular actions and calculated using derived water, nutrient, and energy balances. A typical baseline farm was identified and used to compare indicator performance for which data was available and a comparison was relevant. From the mass and energy balances and indicator calculations, gaps in circularity were identified. To help close the gaps, scenarios to improve the farm's circularity were identified and assessed for feasibility. Each scenario was added to the indicator calculations to quantify the impact on indicator performance.

The results revealed several gaps in circularity, particularly concerning water and waste management. Once through cooling is currently used in the milk processing step leading to a very high water usage and wastewater production. In waste management, the entire liquid fraction of manure ends up in the sewer leading to significant nutrient and water losses. Generally, the farming model involves a trade-off that results in a loss of self-sufficiency, particularly regarding feed, water use, and electricity consumption. This is because no feed crops are grown, and there is no space for large-scale rainwater collection or solar energy production.

The scenario investigation revealed that switching the water source of once-through cooling water from the tap to river water is feasible, greatly impacts indicator calculations, and should be the priority for the farm to improve. The other three scenarios had several pros and cons but may be better suited for future versions of the farm due to the farm's current scale and lack of operational expertise in water treatment.

Despite the farm's efforts and enthusiasm, the indicator performance for most of the farm's circular actions have room for improvement. The farm has put effort into creating a circular economy but still must make significant strides to meet its goals. On top of the scenario recommendations, it was recommended that the farm install more measurement devices to increase the accuracy of future analyses and have a clearer view of process flows to more accurately identify losses.