The transition toward a circular water economy addresses accelerating water scarcity and pollution. A PRISMA-2020 systematic review of 50 peer-reviewed articles (January 2018–April 2024) mapped current technologies and management strategies, seeking patterns, barriers, and critical bottlenecks. Bibliometric analysis revealed the following three dominant patterns: (i) rapid diffusion of membrane bioreactors, constructed wetlands, and advanced oxidation processes; (ii) research geographically concentrated in Asia and the European Union; (iii) industry’s marked preference for by-product valorization. Key barriers—high energy costs, fragmented regulatory frameworks, and low social acceptance—converge as critical constraints during scale-up. The following three practical action lines emerge: (1) adopt progressive tariffs and targeted tax credits that internalize environmental externalities; (2) harmonize water-reuse regulations with comparable circularity metrics; (3) create multi-actor platforms that co-design projects, boosting local legitimacy. These findings provide policymakers and water-sector practitioners with a clear roadmap for accelerating Sustainable Development Goals 6, 9, and 12 through circular, inclusive, low-carbon water systems.

This systematic review synthesizes evidence on economic instruments that mobilize renewable-energy investment in emerging economies, analyzing 50 peer-reviewed studies published between 2015 and 2025 under PRISMA 2020. We advance an Institutional Capacity Integration Framework that ties instrument efficacy to regulatory, market, and coordination capabilities. Green bonds have mobilized roughly USD 500 billion yet work only where robust oversight and liquid markets exist, offering limited gains for decentralized access. Direct subsidies cut renewable electricity costs by 30–50% and connect 45 million people across varied contexts, but pose fiscal–sustainability risks. Carbon pricing schemes remain rare given their administrative complexity, while multilateral climate funds show moderate effectiveness (coefficients 0.3–0.8) dependent on national coordination strength. Bibliometric mapping with Bibliometrix reveals three fragmented paradigms—market efficiency, state intervention, and international cooperation—and highlights geographic gaps: sub-Saharan Africa represents just 16% of studies despite acute financing barriers. Sixty-eight percent of articles employ descriptive designs, constraining causal inference and reflecting tensions between SDG 7 (affordable energy) and SDG 13 (climate action). Our framework rejects one-size-fits-all prescriptions, recommending phased, context-aligned pathways that progressively build capacity. Policymakers should tailor instrument mixes to institutional realities, and researchers must prioritize causal methods and underrepresented regions through focused initiatives for equitable global progress.

This exploratory pilot study analyzes the organizational and environmental determinants associated with stated intention to adopt biogas-solar microgrids within a circular bioeconomy framework. A quantitative, applied, cross-sectional design was used with 71 valid individual responses from participants linked to productive, agro-industrial, livestock, energy, and waste management organizations or projects, selected through nonprobabilistic convenience sampling. The analysis does not measure actual investment, implementation, or use; therefore, the results refer only to declared adoption intention and should not be generalized beyond the sample. The questionnaire measured perceived benefits, barriers, institutional conditions, financial feasibility, environmental value, organizational capabilities, and adoption intention. Content validity was supported by expert judgment, and psychometric reliability was assessed using Cronbach’s alpha and McDonald’s omega. Predictive modeling compared supervised classification, regression, and unsupervised segmentation techniques using train-test validation, cross-validation, and interpretability analyses. ExtraTrees achieved the best exploratory classification performance, with a test ROC-AUC of 0.889, while RandomForestRegressor showed the best regression performance; however, these values should be interpreted as sample-specific evidence rather than as a validated predictive tool. Organizational capabilities and environmental criteria emerged as the most influential predictors, and K-Means suggested two tentative readiness profiles with weak separation. The findings suggest that stated adoption intention is associated with a systemic configuration of organizational maturity, environmental legitimacy, financial feasibility, and institutional support, providing preliminary evidence for future larger sample validation and for decision-support discussions in sustainable energy transitions.

This study evaluates the factors associated with municipal solid waste management performance under a circular economy approach in the municipalities of Cajamarca, Peru. A hybrid analytical design was applied to 120 municipal observations, combining partial least squares structural equation modeling to estimate the measurement and structural properties of four latent constructs—legal-regulatory framework, institutional capacity, operational management, and perceived performance—and XGBoost with SHAP to explore predictive classification of participation in circular economy training. The structural results indicate that operational management plays the central articulating role in linking regulation and institutional capacity to perceived performance, whereas the predictive component showed only modest out-of-sample discrimination (AUC-ROC = 0.519). Overall, the findings suggest that the proposed hybrid pipeline is more informative for explanatory integration and variable-importance analysis than for strong predictive discrimination under the current specification.

Los procesos de tratamiento utilizados en las principales ciudades de Perú no son lo suficientemente eficientes para eliminar las aguas residuales. El objetivo fue evaluar el efecto del polvo de semilla de Moringa oleifera sobre la turbidez de las aguas residuales de los pozos de oxidación del distrito de Cajamarca, 2020. En la prueba se recolectaron siete muestras de agua residual en vasos de precipitados de 500 mL, uno de los cuales sirvió como control para medir los parámetros considerados (turbidez, conductividad, temperatura y pH). Luego, se mezclaron dosis de coagulante (0,5; 0,8; 1 g) en tres muestras de agua residual durante un período de 10 minutos a 150 y 200 RPM. Los diferentes pesos de la Moringa oleifera influyen en la turbidez del agua residual de manera inversa. Los datos no manifiestan diferencia significativa entre la turbidez y las revoluciones (p 0,67) indicando que los valores son similares o que no existe diferencia. Los diferentes pesos de la Moringa influyen en la turbidez del agua residual, la revolución o velocidad de agitación óptima es el de 200 RPM, el peso óptimo es el de 0,8 g. La Moringa disminuye el pH y aumenta la conductividad y la temperatura.

The global water crisis and the urgent need to transition toward regenerative economic models position the circular water economy as a strategic pathway for achieving Sustainable Development Goal 6. While technical feasibility and engineering performance of water reuse technologies have been extensively documented, the socio-organisational and institutional factors conditioning their adoption by industrial and urban entities remain poorly understood. This study addresses this knowledge gap by examining how organisational resources, institutional frameworks, and psychosocial factors are associated with implementation outcomes of circular water economy practices. Using partial least squares structural equation modelling (PLS-SEMs) on survey data from 150 organisational decision-makers across three Peruvian regions (Lima, Trujillo, and Cajamarca), we tested a multidimensional theoretical model integrating resource-based view, theory of planned behaviour, and institutional theory. Results reveal that external regulatory pressure (β = 0.345, p < 0.001), institutional framework quality (β = 0.287, p < 0.001), organisational resource availability (β = 0.273, p = 0.001), and pro-environmental organisational culture (β = 0.255, p = 0.013) show significant positive associations with technology implementation. Counterintuitively, individual attitudes exhibited a negative association (β = −0.350, p < 0.001), suggesting that favourable perceptions disconnected from organisational capacity may generate resistance rather than facilitate adoption. Implementation fully mediates all relationships with performance outcomes (R² = 82.3%), confirming its role as a critical bottleneck in the adoption process. These findings provide empirical evidence for prioritising institutional reforms and organisational capacity-building over awareness campaigns in water reuse promotion strategies, particularly in emerging economy contexts characterised by regulatory fragmentation and limited technical capabilities.