Search Results (762)

Seawater reverse osmosis (SWRO) desalination is electricity-intensive, making its environmental performance highly dependent on the power supply. This study couples site-specific energy-system modelling with life cycle assessment to examine how renewable integration changes both total impacts and life-cycle hotspots. A modelled SWRO plant with a specific electricity consumption of 3.4 kWh m⁻³, derived from a process model for Mediterranean feedwater at 48% recovery with energy recovery devices, was assessed in Gela and Trapani, two grid-connected coastal sites with contrasting wind resources, and Lipari, a non-interconnected island with carbon-intensive backup generation. Grid-only, photovoltaic (PV)-grid, wind-grid, and PV-wind-grid configurations were modelled in HOMER Pro without storage and with excess electricity limited to 13%, then evaluated in SimaPro using Environmental Footprint 3.1. Hybrid configurations supplied 46.7%, 64.4%, and 53.3% renewable electricity in Gela, Trapani, and Lipari, reducing climate-change impacts by 30%, 42%, and 45%, respectively. Renewable integration also lowered fossil resource use, whereas PV-containing scenarios increased land and mineral/metal resource use. As electricity-related impacts declined, chemical consumption became the main non-energy hotspot, particularly for ecotoxicity, freshwater and eutrophication. Environmental performance therefore depends not only on renewable penetration, but also on technology choice and the residual electricity supply. Comprehensive system boundaries are essential when planning lower-carbon desalination for coastal and island water security. Full article

Household food demand mobilizes water, energy, and pollutants throughout supply chains. Using China’s 2023 211-sector input-output table and environmental accounts, this study traces supply-chain water withdrawal, total energy consumption, and actual loads of chemical oxygen demand (COD), ammonia nitrogen (NH₃-N), total nitrogen (TN), and total phosphorus (TP) across 21 food-related sectors, including catering services (restaurants and related commercial food service activities). Household food demand induced 257 km³ of water withdrawal, 11.7 EJ of energy consumption, and the following pollutant loads: COD (1430 × 10⁴ t), NH₃-N (20.9 × 10⁴ t), TN (129 × 10⁴ t), and TP (20.5 × 10⁴ t). Plant-based primary foods led water withdrawal and nutrient loads; animal-source primary foods generated 59.5% of COD; catering services had the largest energy share. Upstream sectors contributed 53.2% of water withdrawal, 75.6% of energy consumption, 45.1% of COD, and 52.2–52.3% of nutrient loads. Covering 80% of each burden required 12 origin–destination links for water withdrawal, 56 for energy consumption, 5 for COD, and 11 for each nutrient, indicating dispersed energy attribution. Grain, other agricultural products, and livestock and other animal products recurred as multi-pressure hotspots. A conditional 20% reduction in their direct intensities lowered water withdrawal by 15.7%, energy consumption by 2.6%, COD by 10.3%, and nutrient loads by 16.1–16.2%. These findings support targeted water and pollution measures alongside broader upstream energy-efficiency action. Full article

The water–energy–food nexus (WEF nexus) is central to sustainable development in arid regions. However, research on nexus evolution based on water consumed during food and energy production remains limited. In this study, the evolutionary patterns and influencing mechanisms of the WEF nexus in an arid region are investigated from a water footprint perspective, taking the middle reaches of the Yellow River Basin in China as a case study. The results show that from 2010 to 2021, the crop water footprint in the study area exhibited distinct varietal differences, with the highest values for legumes and the lowest for tubers, and a spatial pattern characterized by higher values in the north and lower values in the south. The energy–water footprint underwent a structural shift from grey water dominance to blue water dominance in 2015. The coupling coordination degree of the WEF nexus gradually improved from moderate imbalance to mild imbalance. The core obstacle in the water subsystem shifted from water quantity shortage to an imbalance in water use structure, while that in the energy subsystem moved from supply-side constraints to consumption-side constraints. The food subsystem was constrained by rigid factors related to arable land and ecological conditions. Consequently, the core constraint of the WEF nexus has transitioned from independent bottlenecks within individual subsystems to cross-system coupling constraints. Regulating the water footprint on both the production and consumption sides is conducive to the sustainability of the WEF nexus. The findings of this study enrich the regional empirical evidence of the nexus theory and provide a reference for research and practice concerning the optimal allocation of regional resources. Full article

This article presents a scoping review of the literature on digital twins (DTs) for sustainable groundwater resources management, which constitutes a very recent and rapidly expanding research field, with literature moving quickly from conceptual frameworks to application-oriented systems. The literature, selected through the PRISMA 2020 methodology, is organized into seven sub-topics: AI and ML foundations, digital twin architectures and frameworks, aquifer-scale DT applications, agricultural and water–energy–food (WEF) nexus DTs, basin and urban water DTs, sensing, monitoring and IoT infrastructures, and governance, resilience and socio-hydrology. This structure shows how the field is shifting from monitoring and prediction toward integrated decision support, where process-based models, machine learning surrogates, real-time sensing and optimization are combined to support drought mitigation, saltwater intrusion control, irrigation management, climate adaptation and basin-scale planning. Across the reviewed studies, the most recurrent contributions are the construction of hybrid model architectures, the use of DTs to close the loop between observation and control, and the growing recognition that groundwater management must incorporate governance, stakeholder decision-making and socio-hydrological feedbacks. At the same time, the literature still faces key limitations, especially uncertainty quantification, interoperability between models and data streams, transferability to data-scarce settings and limited validation under real operational conditions. Future research should therefore focus on physics-informed and explainable AI, federated and scalable DT architectures, stronger coupling with socio-hydrological and governance frameworks, and more field-tested implementations that can demonstrate robust performance across diverse hydrogeological and institutional contexts. Full article

As variable renewable generation grows, intermittent dispatch of run-of-river hydropower plants may transfer required environmental-flow releases from turbines to spillways, creating conditions that favor total dissolved gas (TDG) supersaturation and may constrain hydropower flexibility. This study presents a reproducible basin-scale screening assessment for 24 selected hydropower plants in the Brazilian Amazon and Tocantins–Araguaia basins. The analysis combines a plant inventory, spillway typology, standardized environmental-flow scenarios, and two configuration-specific linear relationships between unit discharge and the increase in TDG saturation (ΔTDG), derived from digitized Pubugou and Gongzui observations. Two release configurations were examined: flow distributed among all available bays and flow concentrated in a single bay as a theoretical hydraulic bounding case. The Pubugou-based relationship was applied only to broadly comparable ski-jump configurations within 9.1 ≤ UD ≤ 72.3 m³ m⁻¹ s⁻¹, whereas the Gongzui-based relationship was provisionally assigned, as an inventory-level first-order analog, to controlled spillways discharging into stilling basins within 34.6 ≤ UD ≤ 234.6 m³ m⁻¹ s⁻¹. Hydraulically dissimilar cases were classified as NE-H, and cases outside the applicable empirical domain as NE-UD. Digitization sensitivity, regression uncertainty, and model-form selection were explicitly evaluated and documented. None of the distributed-flow scenarios produced a numerical estimate: cases assigned to the Pubugou- or Gongzui-based relationships were classified as NE-UD, whereas hydraulically dissimilar free-surface cases were classified as NE-H. Four single-bay scenarios produced configuration-specific $\Delta \mathrm{T}\mathrm{D}\mathrm{G}$ increments: 22.5–33.4 percentage points for three Gongzui-based cases and 13.6 percentage points for one Pubugou-based case. Upstream TDG was not added, and no plant-specific final concentration or universal ranking was reported. Sinop and Colíder observations were retained as qualitative contextual evidence of limited transferability and the importance of site-specific hydraulics. The outputs support conditional monitoring prioritization under standardized assumptions, not compliance prediction, ecological-risk assessment, or gate-operation recommendations. Synchronized monitoring and plant-specific rating curves are required before TDG-related variables can be incorporated into operational planning. Full article

Central Asia faces increasing pressure on transboundary water, energy and food systems, particularly in the Aral Sea Basin, where hydropower, agriculture and downstream water availability are closely linked. This study applies a spatially disaggregated Water–Energy–Food (WEF) Nexus System Dynamics Model under combined climate–socioeconomic scenarios (SSP1-2.6, SSP2-4.5 and SSP5-8.5) to assess hydropower development and policy pathways at basin and sub-basin scales in the Amu Darya and Syr Darya basins during 2015–2050. At basin scale, mean annual water supply remains stable across scenarios, at approximately 42 and 87 million hm³/year, respectively. Under national hydropower plans, installed capacity nearly doubles by 2050, reaching 10.45 and 10.65 GW, respectively. Food supply is more sensitive to climate–socioeconomic pathways than to hydropower expansion, with 2050 values ranging from 1120 to 1370 tonnes in the Syr Darya and 1405 to 1780 tonnes in the Amu Darya. Spatial simulations show that upstream-only development concentrates energy gains, whereas integrated basin-wide planning delivers more balanced WEF outcomes and the highest Aral Sea inflows, reaching 8.41 million hm³/year and 17,319 hm³/year, respectively. Persistent Amu Darya trade-offs underscore the need for transboundary coordination in reservoir operation, irrigation planning and downstream-flow safeguards. Spatial disaggregation reveals trade-offs concealed by basin-scale averages. Full article

Renewable-powered agricultural water systems are often assessed as solar-pumping devices, but their sustainability depends on a service chain linking crop-water demand, hydraulic duty point, power electronics, storage, water quality, governance, operation and end-of-life management. This structured integrative review synthesizes peer-reviewed and practice-oriented evidence on photovoltaic pumping, hybrid renewable irrigation, grid-interactive pumps, micro-hydro assistance and renewable-powered brackish-water reverse osmosis (PV-RO). Evidence was screened across four source families and coded by service function, energy architecture, hydraulic duty and dominant sustainability pathway; recurring combinations were consolidated using explicit separation and merge rules. It develops an archetype-based screening framework for ex ante appraisal of irrigation, desalination and circularity risks. Seven technology-service archetypes are identified: direct PV pumping, PV-to-tank pumping, PV with electrical buffering, grid-interactive PV pumping, PV–wind hybrid irrigation, micro-hydro-assisted irrigation and PV-RO water making. The framework links each archetype to its operating envelope, evidence maturity, enabling subsystems, sustainability pathways, minimum indicators and ordinal triggers for deeper due diligence. Hydraulic storage is usually the lowest-regret reliability buffer for open-field irrigation, whereas batteries are justified mainly when pressure stability, fertigation timing or night-time operation has high agronomic value. PV-RO is a distinct water-making archetype and is environmentally defensible only where feed-water characterization, energy recovery, pretreatment, product-water agronomy, membrane management and permitted concentrate disposal are embedded in design. Two synthetic applications demonstrate archetype selection and due-diligence escalation. Responsible deployment requires service-oriented screening that integrates hydraulic design, groundwater governance, procurement quality assurance, circularity obligations and social inclusion before field implementation. Full article

Agricultural management influences progress towards carbon neutrality through its effects on water consumption, energy use, and greenhouse gas (GHG) emissions. However, few studies have translated policies across sectors into management scenarios and evaluated their combined consequences for the agricultural carbon neutrality. We quantified the water, energy use, and carbon nexus for wheat, rice, and corn production across the North China Plain using 2018 as a baseline scenario. We then evaluated conditional management scenarios informed by China’s 14th Five-Year Plan. The three crop production generated net emissions of 1.8 × 10¹⁰ kg C yr⁻¹ in 2018, while cropland net ecosystem productivity offset 16.9% of GHG emissions related to crop production. Energy use was positively correlated with GHG emissions (r = 0.74, p < 0.01). The integrated scenario combining a 30% reduction in nitrogen fertilizer, more efficient nitrogen fertilizer production, sprinkler irrigation, and a 50% crop straw return rate reduced the water footprint, energy use, and GHG emissions by 4.9%, 27.6%, and 39.2%, respectively. By contrast, drip irrigation alone reduced the water footprint but increased energy use by 6.8% and GHG emissions by 12.9%. The results show that water saving measures do not necessarily improve the carbon neutrality when their energy requirements are overlooked. These findings also provide more enlightenment for local policy-makers. Full article

The water–energy–carbon (WEC) nexus is central to sustainability, yet the role of water quality as a potential moderator within this nexus remains empirically underexplored. Using a fixed-effects panel regression model applied to provincial-level data from the Yellow River Basin over the period of 2007–2022, this study provides systematic evidence that water quality significantly moderates the WEC nexus. The empirical findings indicate that (1) water quality negatively affects the WEC nexus significantly; (2) the moderating effect presents spatial heterogeneity, showing greater carbon reduction potential in middle and lower reaches; and (3) the marginal impact of water cycle energy consumption on carbon emissions declines monotonically with improvements in water quality, with a sample-specific estimated critical point identified at a compliance rate of 88.159%—below which the marginal effect remains positive and above which it turns negative. (4) The moderating effect exhibits pronounced spatial heterogeneity, being significantly positive in the middle and lower reaches but insignificant in the upper reaches, and is significantly strengthened after the implementation of China’s strictest water resource management policy in 2013. These results suggest that water quality serves as a strategic lever for synergizing WEC governance. The findings offer theoretical and practical insights for adjusting the tightly coupled WEC nexus in the Yellow River Basin, with implications for region-specific and threshold-oriented policy design. Full article

Freeze desalination (FD) is being reconsidered as a low-temperature desalination route because it separates water through ice formation rather than evaporation or membrane pressure. This review examines FD from the perspective of sustainable water–energy systems, with emphasis on applications where conventional desalination may face technical or energy limitations. Unlike general reviews focused mainly on freezing principles, this work connects crystallization mechanisms, experimental performance, energy integration, and scale-up barriers. The literature analyzed, consisting primarily of studies published between 2015 and 2026, was grouped into four areas: modeling and simulation, experimental and pilot-scale validation, technological integration, and energy–economic assessment. Recent progress has been reported in eutectic freeze crystallization, vacuum-assisted ice–brine separation, ice morphology control, LNG cold recovery, solar-assisted FD, and hybrid systems that combine desalination with cooling or energy recovery. Reported performance varies widely. Reported SEC varies by more than an order of magnitude: values near 3 kWh/m³ occur mainly under favorable integration or external-cold assumptions, whereas conventionally refrigerated laboratory and pilot systems can require substantially more energy. This difference shows that FD performance depends strongly on crystallizer design, feedwater composition, separation strategy, and cold-energy recovery. FD should not be viewed as a direct replacement for RO, MED, or MSF. Its strongest potential is in hypersaline brine treatment, LNG terminals, cold regions, off-grid systems, island communities, and decentralized water production coupled with renewable or waste-cold sources. Full article

This study analyzes wastewater treatment plants (WWTPs) in Querétaro, Mexico, over a decade (2013–2022), highlighting the interdependencies between pollutant removal, energy consumption, and greenhouse gas (GHG) emissions. Despite being conventional systems, the WWTPs achieved high pollutant removal efficiencies (92–97% BOD₅, 50–60% TN), preventing 146.1 MtCO₂e over ten years. However, this efficiency came with some drawbacks: a 10% reduction in pollutants increased electricity consumption by 7%. CO₂ emissions from grid-fed operations increased by 130% between 2021 and 2022, emphasizing the carbon intensity of improving water quality. In 2022, the system emitted 0.002 tCO₂e/m³ of treated water, due to indirect N₂O and CH₄ emissions from untreated flows and electricity consumption. With only 70% of wastewater treated and minimal energy recovery, the existing infrastructure offers environmental benefits but operates near its efficiency limits in the face of increasing demand. The transition to energy-neutral models, through biogas cogeneration, solar integration, and advanced nutrient removal, is crucial for achieving urban water systems resilient to climate change. This case study provides valuable insights for cities seeking to balance water security, sustainability, and decarbonization in rapidly developing regions. Full article

Water-intensive industries in the Mediterranean face supply stress and decarbonisation pressure simultaneously. We develop an operations-research decision-support framework that treats the firm as one node of a small industrial resource cluster and prices the cost and carbon-equivalent emissions of five alternative supply trains—municipal water, river water, groundwater, rainwater harvesting and brewery wastewater reuse—within a multi-objective Linear Program. Each train carries engineering-grounded expenditures, energy intensities and grid emissions, and a weighted-sum scalarisation is solved daily for 365 days under three managerial scenarios. On a Cretan microbrewery whose 2022 demand of 5250 m³ is met from the municipal network, the balanced and cost-focused scenarios coincide on a single optimum that cuts the Levelised Cost of Water by 25.3% and emissions by 40.7%, while the eco-friendly scenario yields a 19.3% cost and 51.7% emissions reduction. LP duality, shadow prices and an extended sensitivity programme (diversification, capacity, grid factor, discount rate, RO recovery and demand profile) turn the optimisation into a decision-support package: optimal daily allocations, shadow-price signals on capacity and demand, and robustness diagnostics for capital planning, dispatch and risk management. Results are site-specific, but the framework and its diagnostics transfer in structure to clusters sharing the same convex-polytope source geometry; transposition to energy cooperatives is future work. Full article

Water management has become a critical dimension of sustainable architecture, as buildings increasingly interact with limited freshwater resources and energy-intensive water treatment systems. In this context, the present study provides a comprehensive bibliometric analysis and review of scientific research addressing water management within sustainable buildings in order to assess the most important quantitative information about this topic and identify the most relevant research trends. A total of 3283 documents indexed in Scopus before 2024 were identified and analyzed through a two-stage approach combining bibliometric performance indicators and network analysis using SciMAT (v1.1.06). Publication trends, document types, leading countries, institutions, sources, and thematic distributions were examined, followed by analysis of the conceptual evolution of the field. Results revealed a sustained growth in scientific output, with engineering, environmental science, and materials science as the dominant subject areas. Keyword and cluster analyses identified construction materials and their water-related properties and water resource management as central research themes, while also highlighting the nexus between water, energy, and environmental impacts in building sustainability. Based on the bibliometric findings, a structured review of current research is presented following a circular-economy-oriented framework adapted to water, organized around three strategies: decreasing water demand, optimizing the use of non-conventional water resources, and retaining water through reuse. Full article

The decarbonization of essential water supply infrastructure is a critical challenge for water-stressed and geographically constrained regions, particularly islands where both water and electricity systems are highly dependent on external or fossil-based resources. In Northern Cyprus, approximately 70% of domestic water demand is met through imported water via pipeline, while electricity generation relies predominantly on fuel oil, resulting in high greenhouse gas emissions and environmental burden. This study evaluates an integrated renewable energy-based supply system using a medium-scale concentrating solar power (CSP) plant with parabolic trough collectors coupled to thermal desalination. The proposed configuration is assessed as an alternative energy-driven infrastructure option for reducing dependence on imported water and fossil-based electricity. System performance was evaluated by estimating electricity and freshwater production under local climatic conditions, demonstrating that the proposed configuration can meet both the associated electrical energy requirements and domestic water demand in the selected region. A cradle-to-gate life cycle assessment (LCA) was conducted to quantify the environmental impacts of the integrated system and support sustainability-oriented decision-making. The LCA results identify residual fossil-based electricity, phosphoric acid consumption, and brine discharge as the main environmental hotspots. Overall, the findings show that CSP-driven desalination can provide a viable and more sustainable option for integrated energy and water supply in water-scarce coastal regions with high solar potential, highlighting its relevance for renewable energy integration, water-energy nexus planning, and resource-efficient infrastructure development. Full article

The increasing contribution of non-dispatchable renewable energy sources has changed the operating patterns of hydropower plants, especially in run-of-river schemes with limited storage capacity. Under intermittent dispatch, turbine shutdowns may occur while environmental-flow requirements must still be maintained. In these situations, spillway releases become more frequent, creating hydraulic conditions that can lead to total dissolved gas (TDG) supersaturation downstream. This study evaluates TDG supersaturation as an operational constraint in an Amazonian run-of-river hydropower plant. This assessment combines field measurements with controlled laboratory exposure tests using representative native fish species. Total gas pressure (TGP) was measured in both field and laboratory settings and converted into TDG saturation percentages. A laboratory-scale TDG generation system was developed to reproduce supersaturation conditions associated with spillway operation. Field measurements recorded TDG levels above 130% during spillway-activation events associated with dispatch decisions. In the laboratory, exposure tests showed rapid loss of viability in native Amazonian fish at TDG levels of 115% and above. These results indicate operational warning ranges for sustained spillway use. The findings suggest that TDG supersaturation should not be treated solely as an environmental issue. Rather, it represents a technical constraint on hydropower dispatch in systems with increasing renewable penetration. Incorporating TDG-related limits into operational planning and spillway management may help preserve hydropower flexibility while supporting environmental compliance. Full article