IntroductionGroundwater recharge is traditionally understood to be primarily controlled by precipitation and other climatic processes. However, intensive anthropogenic water management and urbanization may weaken this relationship in megacities. This study investigates hydrological decoupling at the municipal scale in Beijing, China, and quantifies the relative contributions of anthropogenic and climatic drivers to groundwater dynamics.MethodsWe analyzed 19 years of multisource hydroclimatic data using nonparametric trend analyses, antecedent-window correlation analyses, and hierarchical multiple regression. Spatial analyses were conducted to examine the potential effects of impervious surfaces and managed vegetation on natural groundwater recharge. Future drought risks and groundwater trends were also assessed under the SSP2-4.5 and SSP5-8.5 climate scenarios for 2024–2100.ResultsAnnual precipitation showed no statistically significant correlation with groundwater depth (Spearman’s ρ = 0.04, p = 0.624), and no significant delayed associations were identified across antecedent climatic windows of 1–12 months. Hierarchical regression attributed 60.0% of the variance in groundwater depth to anthropogenic drivers, represented by total water supply, compared with 35.6% attributed to natural climatic forcing. Spatial analyses further indicated that dense impervious surfaces and managed vegetation may constrain natural recharge and weaken the influence of meteorological variability on groundwater dynamics. Both future climate scenarios indicated substantial drought risk, while historical evidence suggested that groundwater trajectories would remain strongly influenced by active water management.DiscussionThe findings indicate that anthropogenic water management can become a dominant control on urban groundwater dynamics, potentially outweighing the influence of climatic variability. This hydrological decoupling challenges conventional assumptions about precipitation-driven groundwater responses and highlights the importance of integrating water governance, urban land-surface characteristics, and climate adaptation into groundwater management strategies for heavily urbanized basins.
The Guangdong–Hong Kong–Macao Greater Bay Area is marked by pronounced urban heterogeneity, so that a uniform account of its carbon emission drivers is unlikely to hold. Using panel data for 11 cities from 2015 to 2023, this study applies the Generalized Divisia Index Method to decompose eight drivers of emission change and to classify the cities by their factor contribution structures. Economic growth (G) and output carbon intensity (CI) are the largest positive and negative contributors in ten of the eleven cities (mean G = +19.18%, mean CI = −9.94%), the exception being Macao. An exploratory Ward clustering of the four most variable factors, cross-validated against k-means, distinguishes four types of driving structure—carbon-intensity suppression, economic-scale driven, energy-scale expansion, and a specialized service-structure type (Macao); an innovation index combining research and development (R&D) intensity and patent density varies independently of these types. Decoupling is likewise uneven, ranging from strong decoupling in three cities (Foshan, Zhongshan and Hong Kong; Tapio elasticity t = −0.152 to −0.437) to weak decoupling in six (0.133 ≤ t ≤ 0.462) and expansive coupling in Huizhou and Macao. Per-capita emissions and energy-structure carbon intensity show marked dispersion. These findings inform a three-tiered policy discussion—differentiated measures, collaborative governance, and data support—for coordinated low-carbon governance in urban agglomerations.
IntroductionAgricultural-waste-derived activated carbons offer a sustainable alternative to conventional adsorbents; however, most studies rely on single biomass precursors and evaluate adsorption using only one model pollutant.MethodsIn this study, a hybrid activated carbon (HAC) derived from banana peel and olive pomace was developed and evaluated for the removal of four structurally distinct dyes: methylene blue (MB), methyl orange (MO), crystal violet (CV), and Eriochrome Black T (EBT). The effects of adsorbent dosage, pH, and contact time were investigated, followed by adsorption isotherm, kinetic, and regeneration analyses.ResultsAn adsorbent dosage of 12 g/L and pH 2 provided the most favorable adsorption conditions. The hybrid activated carbon was found to have a high removal efficiency of 97.71% for MB, 98.41% for MO, 98.70% for CV, and 98.95% for EBT, respectively, under the optimized conditions to remove different dyes with different chemical structures. The equilibrium data were generally better described by the Langmuir model, while the adsorption kinetics showed stronger agreement with the pseudo-second-order model. HAC exhibited maximum adsorption capacities of 130.34, 99.70, 112.42, and 114.52 mg/g for MO, MB, CV, and EBT, respectively, with hybridization enhancing the adsorption capacities toward MO and EBT compared with the individual activated carbons. Regeneration experiments showed that HAC retained adsorption functionality after ten cycles, although removal efficiencies decreased to approximately 42%–56%.DiscussionThe results in this study validate the potential of olive pomace and banana peel-based hybrid activated carbon as a waste derived, reusable material for the removal of dyes from contaminated wastewater, thereby valorizing agricultural waste and promoting sustainable resource utilization.
Ecological degradation has emerged as a critical challenge to achieving sustainable development, particularly in G20 economies where economic growth, social welfare objectives, and environmental constraints frequently interact. Using annual data for 17 G20 countries over 2000–2021, this study examines the effects of social welfare (SCWF), economic policy uncertainty (ECPX), trade openness (TROP), life expectancy (LIEX), natural resource rents (NARN), and tourism (TRSM) on ecological footprints (ECFP). Employing a Pooled Mean Group–Autoregressive Distributed Lag (PMG-ARDL) model, the analysis captures both short-run dynamics and long-run equilibrium relationships while accounting for cross-sectional dependence and heterogeneity across countries. The findings reveal that natural resource rents and social welfare expansion significantly increase ecological footprints, indicating that resource-intensive development and consumption-oriented welfare systems can undermine environmental sustainability. Life expectancy and economic policy uncertainty are negatively associated with ecological footprints. These estimates do not establish causal effects or demonstrate the influence of environmental regulation, which is not measured in the model. Trade openness exerts mixed effects, increasing environmental pressure in the short run but promoting ecological sustainability in the long run, whereas tourism consistently intensifies ecological degradation. These findings highlight the complex trade-offs between economic prosperity, social progress, and environmental protection in G20 economies. From an SDG perspective, the results provide important implications for achieving SDG 8 (Decent Work and Economic Growth), SDG 12 (Responsible Consumption and Production), SDG 13 (Climate Action), and SDG 15 (Life on Land). The study advocates integrated policy frameworks that promote sustainable resource management, environmentally responsible tourism, and balanced welfare strategies to support long-term ecological resilience and sustainable development.
Most of the user-interface of toilets is associated with in-situ, decentralised wastewater treatment systems. Specifically, on-site sanitation systems (OSS) and decentralised wastewater treatment systems (DEWATS) are mainly used to treat toilet blackwater (faeces, urine, and flush water). Though ideal, malodour generated within these systems can hinder their adoption, especially where sanitation infrastructure is limited. Perceived desirability and social acceptability of toilets are negatively influenced by malodour and is a major contributor to its non-use and disuse. Obnoxious odours emanate largely from bacterial activity under anaerobic conditions, through the production of volatile organic sulphur compounds, nitrogenous compounds, and volatile fatty acids. Conventional odour-abatement strategies are plagued by substantial operational inputs and generation of secondary waste streams. Against this backdrop, bacteriophages are being investigated as a precision biological option, due to their host-specificity, and ability to self-amplify. This review examines bacteriophage-based strategies alongside established approaches for managing odour-causing microorganisms, with emphasis on emission points, biochemical processes, toxicity, translational bottlenecks, and research priorities.
