Water Supply Research Articles

Research Advances in Removal Efficiency and Mechanism of Microplastics in Drinking Water Treatment Plants

Microplastics, as a novel type of environmental pollutant, have attracted notable attention in environmental research due to their widespread distribution and potential biological toxicity. Drinking water treatment plants play a crucial role in ensuring the safety of the water supply, with a particular focus on the removal efficiency of microplastics in drinking water treatment plants. Different treatment processes in water plants exhibit various removal efficiencies of microplastics and they operate through distinct removal mechanisms. To comprehensively analyze the removal efficiency and mechanism of microplastics in drinking water treatment plants, this study first examined the abundance and removal efficiency of microplastics of the influent and effluent of drinking water treatment plants. Subsequently, this study reviewed the removal efficiency and mechanism of four commonly used treatment processes： coagulation/flocculation/sedimentation, sand filtration, membrane filtration, and disinfection. The shortcomings and gaps in current studies were also pointed out. Finally, the assessment of microplastics abundance and human exposure in tap water was summarized and the future research direction was prospected from the perspectives of standardized sampling detection methods, nanoplastic detection, microplastics release in water supply systems, and risk assessment.

Recycling of Reclaimed Water in China: Current Situation, Development Trend, and Countermeasures

Recycling of reclaimed water is an important way to develop water resources and reduce pollution discharge. At present, the utilization rate of reclaimed water is low in China and the recycling system is inadequate. Therefore, from the perspective of "carbon peaking and carbon neutrality" dual carbon propulsion and "water resources protection, water environment governance, and water ecological restoration" three water co-governance, this study first systematically combined the water resources situation, water supply structure, urban domestic sewage collection and treatment, and recycling of reclaimed water in all provinces （municipalities and autonomous regions）. Data collected in 2022 showed that the capacity of municipal sewage treatment was approximately 62.689 billion cubic meters annually, the capacity of reclaimed water production was approximately 28.98 billion cubic meters annually, and the utilization rate of reclaimed water was approximately 28.76%. There were 20 provinces with the utilization rate of reclaimed water less than 25%, among which the utilization rate of reclaimed water was less than 5% in Shanghai, Chongqing, Xizang, and Jiangxi. The situation of water resources did not match the development of the utilization rate of reclaimed water. Therefore the utilization paths of reclaimed water must be broadened and the utilization rate of reclaimed water must be improved crucially. Moreover, the related policies, laws, and regulations and standards of reclaimed water in China were listed. The technical and benefit feasibility analysis of reclaimed water utilization was carried out, and the development trends and existing problems of reclaimed water utilization in China were investigated. Finally, the countermeasures and suggestions of the recycling of reclaimed water from the aspects of technology development, management policy, fund guarantee, and publicity incentive are proposed, to promote the resource treatment of sewage, realize the synergistic reduction of pollution and carbon emissions in sewage treatment, help achieve the goal of carbon peak carbon neutrality, and accelerate the construction of a beautiful China. This study can provide reference and guidance for regional recycling of reclaimed water.

Inferring failure risk of on-site wastewater systems from physical and social factors

Aging infrastructure and climate change present emerging challenges for clean water supply and reliable wastewater services for communities in the United States (US). In Georgia, for example, the failure rates of on-site wastewater systems (OWTS) have increased from 10% to 35% in the last two decades as the systems age. In this work, we develop a hierarchical Bayesian model to understand the different contributions of physical and social factors driving OWTS failures using a long-term collection of 201,000 Georgia’s OWTS inspection records. The out-of-sample validation accuracy of our hierarchical Bayesian model is 70% within Georgia, outperforming other machine learning models that do not consider the multiscale nature of the problem. Overall, we find counties that experience more extreme precipitation and are situated in steeper-sloped regions are significantly associated with increased failure risks. Uncertainties, meanwhile, are largely associated with counties experiencing more precipitation and have lower median housing value.

Optimal Allocation of Urban Water Resources Based on Multi-Objective Nutcracker Optimization Algorithm

The imbalance between water supply and demand (WSD) has been growing noticeable as a result of the economy’s fast expansion which can be effectively alleviated using optimal allocation of water resources. An urban water resources allocation (WRA) model based on the innovative Multi-Objective Nutcracker Optimization Algorithm (MONOA) is proposed in this study. Taking into account economic, social and ecological benefits, a comprehensive multi-objective optimization (MOO) model is established. By introducing the opposite learning strategy, non-dominated sorting approach and crowding distance mechanism to a recently reported intelligent optimization algorithm called the Nutcracker Optimization Algorithm (NOA), the novel nature-inspired metaheuristic algorithm MONOA is proposed to solve the multi-objective optimization model. The MONOA is evaluated on ten benchmark test functions, and it exhibits superior distribution and convergence by comparing with some highly cited algorithms. The proposed model is applied to Handan, China, in order to obtain a reasonable water allocation scheme in the planning year. The simulation results reveal that the economic benefit is in the range CNY [1.36, 1.44] × 1011, water shortage is in the range [0.66, 0.98] × 108 m3 and COD emission is in the range [3.70, 3.91] × 104 t in all the obtained Pareto solutions. The water resources management departments might create customized water allocation plans by balancing different goals and taking preferences into account. Moreover, the proposed method is a general approach that can be applied to many other cities. Hence, it is of great significance to the sustainable development and utilization of urban water resources.

Water Quality Assessment using Selected Macroinvertebrate Based Indices and Water Quality Index of Sungai Air Hitam Selangor

A study was conducted from July to December 2022 at Sungai Air Hitam, a small tributary of the Selangor River located within the Tanjung Karang Sub-basin in Malaysia (coordinates: 3° 24' 27" N, 101° 25' 54" E to 3° 28' 14" N, 101° 26' 59" E). This confluence is situated near three major downstream water treatment plants. The study assessed six water quality parameters—pH, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia (NH3), and suspended solids (SS)—to calculate the Water Quality Index (WQI). Macroinvertebrates were sampled simultaneously using the dipping net method to obtain biotic indices for further evaluation of water quality. The results indicated that the WQI classified Sungai Air Hitam as Class III, with scores ranging from 56.9 to 64.6, suggesting the river is suitable for water supply and fisheries. However, the Biological Monitoring Working Party (BMWP) index categorized the water quality as poor, with scores between 30 and 42. Similarly, the Average Score Per Taxon (ASPT) ranged from 3.25 to 5.25, indicating pollution or environmental impact, while the Family Biotic Index (FBI) further classified the river as having poor to very poor water quality, with scores between 6.57 and 8.11. Overall, the study suggests that Sungai Air Hitam has experienced some degree of ecological degradation. These findings emphasize the need for continuous monitoring and remediation efforts to preserve and restore water quality.

Assessing climate-driven glacial retreat, snow-cover reduction and GLOF risks: implications for water resource management amid rising global temperatures and CO2

Context The consequences of climate change, including alterations in snow and glacier patterns and rising temperatures, pose a risk of glacial lake outburst floods (GLOFs), which can have cross-border impacts, leading to the loss of life and property downstream. Aims This research focused on the assessment of changes in snow cover within Chitral district imposed by temperature increase. Methods ArcGIS and Origin programs were used in this research to study the glacier pattern of Chitral. Results Therer was a significant increase of 266.7% in urban development and an expansion of 135.9 km2 in agricultural areas within this remote mountainous region. The findings of the study show that in the year 2000, >51.6% of Chitral district’s total land was covered by snow during early winter. However, this coverage drastically declined to ~6.8% by 2008. Across the initial two 4-year periods, ~44.7% (5694.6 km2) of the glaciated area transitioned to barren rock, whereas the overall reduction in snow-covered areas accounted for ~43.3% (5514.6 km2). Conclusion Owing to the increasing stress on freshwater resources, it is essential to conduct thorough analyses and monitoring of snow patterns to ensure sustainable freshwater availability and effective environmental risk management. Implications This study emphasises the critical consequences of climate-driven glacial retreat, waning snow cover and increased risks of glacial lake outburst floods (GLOFs) for the management of water resources with the rise in global CO2 and temperatures levels. These changes threaten the timing and availability of water supply, with impacts on agriculture, ecosystem and hydropower. Effective adaptation measures and sustainable management practices are crucial to alleviate these risks and ensure water security in a warming world.

Integrated Model of Water Infrastructure Development for Water Resources Sustainabilitu (Case Study in Tual City, Indonesia)

BACKGROUND AND OBJECTIVES: Development in Indonesia which is emphasized on the large island/land areas in the Western Region of Indonesia, has resulted in the underdevelopment of the coastal areas and islands in the Eastern Region of Indonesia. Thus, the welfare and economic conditions of the people in the Eastern Region of Indonesia are lower. Development activities oriented in mainland areas or large islands also have the potential to threaten development sustainability, especially in environ-mental aspects. This research aimed to build an integrated model for water infrastructure de-velopment.METHODS: This study used a quantitative approach by collecting and analyzing data through questionnaires and used dynamic system analysis to build an integrated water infrastructure model. FINDINGS: The results of the study found that environmental degradation that occurred in Tual City was caused by high economic activity around the port of Tual, water supply conditions for the people in the exploitative small island of Tual City, as well as pollution and degradation of the soil quality around the residential area of Tual City. CONCLUSION: The clean water infrastructure integration model with rainwater harvesting and artificial reservoirs can save water purchase costs and increase water supply availability to promote sustainability without causing environmental degradation.

Evaporation and the difference between precipitation and evaporation in Bulgaria

This study examines the total evaporation and precipitation-evaporation difference in Bulgaria. Data from ERA5-Land reanalysis for the period 1979–2023 were processed using statistical methods. The results show that the main factors for evaporation in Bulgaria are air temperature and precipitation. Evaporation has a positive trend due to the rise in air temperature. This trend is significant only in mountainous regions, which are well-supplied with water. Evaporation is somewhat limited in the other parts of the country because of the water deficits in the warm part of the year. Precipitation is a possible source of water for the earth’s surface, but there has been only an insignificant increase in it in recent decades. Precipitation-evaporation difference remains relatively unchanged during the studied period, which is a favorable trend, as there is no increase in the water deficit in Bulgaria on an annual basis. In addition, most of the country has positive values in terms of the average annual values of precipitation-vaporation difference. However, there is a need to introduce monitoring of actual evaporation, because this study has shown that different calculation methods give different results, which is a significant problem in determining how much precipitation remains in a given area. The exact values of this indicator are extremely important for various sectors of the economy such as agriculture, water supply and sewage, transport, energy, etc.

Sustainable and Self-Sufficient Fresh Water Through MED Desalination Powered by a CPV-T Solar Hybrid Collector: A Numerical and Experimental Study

The effects of global warming are severely recognizable and, according to the OECD, 47% of the world’s population will soon live in regions with insufficient drinking water. Already, many countries depend on desalination for fresh water supply, but such facilities are often powered by fossil fuels. This paper presents an energy self-sufficient desalination system that runs entirely on solar power. Sunlight is harvested using parabolic trough collectors with an effective aperture area of 1.5 m × 0.98 m and a theoretical concentration ratio of 150 suns, in which a concentrator photovoltaic thermal (CPV-T) hybrid-absorber converts the radiation to electricity and heat. This co-generated energy runs a multi-effect distillation (MED) plant, whereby the waste heat of multi-junction concentrator solar cells is used in the desalination process. This concept also takes advantage of synergy effects of optical elements (i.e., mirrors), resulting in a cost reduction of solar co-generation compared to the state of the art, while at the same time increasing the overall efficiency to ~75% (consisting of an electrical efficiency of 26.8% with a concurrent thermal efficiency of 48.8%). Key components such as the parabolic trough hybrid absorber were built and characterized by real-world tests. Finally, results of system simulations, including fresh water output depending on different weather conditions, degree of autonomy, required energy storage for off-grid operation etc. are presented. Simulation results revealed that it is possible to desalinate around 2,000,000 L of seawater per year with a 260 m2 plant and 75 m3 of thermal storage.

ESTIMATING OPERATIONAL COSTS FOR ENHANCED CONTINUITY IN WATER SUPPLY AND SANITATION SERVICES: AN INVERSE DATA ENVELOPMENT ANALYSIS APPROACH IN CHILEAN UTILITIES

Study regionThe largest 23 water utilities in Chile providing water and sanitation services to 97.9% of total urban customers. Study focusThis study introduces an innovative methodological framework based on inverse data envelopment analysis technique to quantify the additional operational costs required for water utilities to enhance their water supply and sanitation continuity while maintaining their techno-economic efficiency. This framework is pivotal for setting realistic continuity targets and assessing potential impacts on water and sanitation tariffs, thereby aiding in policy and operational planning within the water sector. New hydrological insights for the regionThe analysis was performed across four distinct continuity scenarios revealing substantial cost variability contingent on continuity targets, current service levels, and the efficiency of each utility. Results showed a median operational cost increase that varied from 28.41% in the most stringent scenario to just 0.27% in the most lenient. The financial implications of meeting these costs through water and sanitation tariffs would necessitate a median monthly increase in water bills, ranging from $17.24 per household in the most demanding scenarios to only $0.01 per household in the more lenient scenarios. This research provides a valuable tool for water sector regulators and managers, enabling informed decision-making by balancing service improvement objectives with economic considerations and customer willingness to pay for enhanced service continuity.

Mitigating aging infrastructure risks: An optimized epoxy resin system for water supply pipeline rehabilitation

Urban water supply networks are crucial for ensuring the delivery of safe drinking water to urban populations; however, the aging infrastructure in these systems has led to a rising incidence of leaks and frequent pipeline failures, posing serious risks. Traditional repair approaches encounter limitations in terms of efficiency, durability, and environmental safety, particularly when employed in potable water pipelines. To address these challenges, we developed a novel multi-component amine-cured epoxy resin system specifically optimized for in-situ curing under ambient conditions. This study comprehensively examines the mechanical properties, water absorption behavior, and curing kinetics of this resin system, formulated to reduce volatile organic compound emissions while enhancing durability under prolonged water exposure. Experimental findings demonstrate that the E2 formulation exhibited superior tensile strength, flexural properties, and fracture toughness relative to other formulations, with a two-stage water absorption model accurately predicting resin behavior in moisture-laden environments. Moreover, finite element modeling and laboratory testing confirmed the influence of bubble defects on mechanical performance, and a negative pressure defoaming technique effectively reduced defect volume, resulting in a 17.6% improvement in tensile strength. Collectively, this research advances the practical application of rapid-curing resins, offering a resilient, safe, and sustainable solution for the rehabilitation of aging water pipeline networks.

Data-driven forecasting framework for daily reservoir inflow time series considering the flood peaks based on multi-head attention mechanism

Accurate and reliable daily reservoir inflow forecast plays an essential role in several applications involving the management and planning of water resources, such as hydroelectric generation, flood control, water supply, and basin ecological dispatching. Runoff usually exhibits strong non-linearity, high uncertainty, and spatial and temporal variability. Existing techniques fail to capture complete dynamics change processes effectively. A data-driven forecasting framework for daily reservoir inflow time series considering the flood peaks based on a multi-head attention mechanism was developed, referred to as the GWOCS-VMD-CNN-Transformer (GCVCT). First, the model utilize Grey Wolf Optimizer coupled with Cuckoo Search (GWO-CS) algorithms to optimize parameters in variational mode decomposition model (VMD). This approach helps obtain highly correlated intrinsic mode function (IMF) components, enhancing the frequency resolution of the input dataset. The proposed method overcomes the bottleneck of other available methods by decomposing the time series to capture the main long-term and short-term properties of hydrological processes. Second, the convolution neural network and Transformer (CNN-Transformer) are based on a multi-head attention mechanism as the objective predictive method. Finally, six evaluation indicators verify the performance of the proposed approach. The approach’s reliability was evaluated using the historical daily reservoir inflow data from the Xiluodu (XLD) and Wudongde (WDD) reservoirs in the Jinsha River Basin, China. Several single and hybrid models were developed for comparative analysis. The results indicate that the proposed ensemble approach fits better than other developed model methods. The GCVCT model showed excellent performance in forecasting the inflows of XLD and WDD reservoirs, with NSE values of 0.985 and 0.984, respectively. Furthermore, the GCVCT framework forecast capacity for peak inflow was further verified through discussion and analysis of the 48 peak flows during the validation period, consistently outperforming other models in predicting peak flow for both study reservoirs. This framework provides an effective method for the scientific optimal scheduling of hydropower reservoirs, enabling more sustainable and efficient management practices. It also demonstrates the potential of powerful deep-learning models in intelligent hydrological forecasting.

Removal efficiencies for 52 pesticides and pharmaceuticals from wastewater effluent by coupling solar heterogeneous photo-oxidation with TiO2 and infiltration in saturated soil column

Water resource management has become a hot button issue in recent decades. Countries facing water shortages as a result to climate change must adapt their water supply. The reuse of wastewater treatment plant effluents is becoming increasingly common around the world. However, the effluent quality must be improved before its reutilization to avoid contamination of the receiving environment. Pharmaceuticals and pesticides are particularly monitored because of their ubiquitous behaviours and limited removal by conventional wastewater treatment plants. The aim of this study was to combine heterogeneous photo-oxidation with TiO2 and soil infiltration to increase the elimination of contaminants of emerging concern (CECs). These advanced treatments were applied on an effluent coming from a WWTP equipped with a Ultrafor membrane bioreactor (sludge ages: 8–30 days, biomass concentration: 8-12 g.L−1, hydraulic retention: 6.7-8 h). The concentration of CECs was determined to evaluate the efficiency of coupling treatments. Photo-oxidation alone showed an impressive 98 % removal under spring conditions, while 66 % removal was observed under winter conditions. The differences observed for photo-oxidation were related to UV flux density, lower in winter than in spring (4.4 kJ.L−1 vs 6.6 kJ.L−1) and initial concentrations of the effluent higher in winter (50 μg.L−1 vs 26 μg.L−1). For both experiments, additional soil infiltration increased the global concentration of CECs removal to at least 89 % with equal removal contributions observed for some compounds. From the 52 CECs quantified in the WWTP effluent, at least 30 were totally removed by the advanced treatments while 4 compounds showed recalcitrant behaviours with global removal <60 %.

Identification of the number of leaks in water supply pipes based on wavelet scattering network and Bi-LSTM model with Bayesian optimization

Water supply pipeline leaks have significant impacts on urban areas and daily life. Acoustic techniques are widely applied in its leak detection, but there is a lack of research on quantifying multiple leaks in pipelines. This study presents a novel approach using a Wavelet Scattering Network (WSN) and Bi-directional Long and Short-Term Memory (Bi-LSTM) model with Bayesian optimization to identify leak quantities accurately. The WSN autonomously extracts signal features, which are subsequently processed by the Bi-LSTM for classification. Through Bayesian optimization, the model’s hyperparameters are refined to enhance performance. The results exhibit an impressive 90.8 % classification accuracy, showcasing the model’s effectiveness in accurately identifying leak quantities. In comparison with existing models, the proposed method stands out for its superior recognition accuracy, shorter training time, and enhanced noise immunity. Ablation experiments further confirm the distinct roles and contributions of the WSN, Bayesian optimization, and Bi-LSTM components in achieving these exceptional results.

Effects of a bypass-type multistage sand-filled dam on water supply in a drought-vulnerable area in Mullocheon catchment, South Korea

Study regionMullocheon catchment, Gangwon-do, South Korea Study focusClimate change can lead to extreme droughts worldwide, and regions relying on valley streams without large reservoirs are more vulnerable to drought. To address this, a bypass-type multistage sand-filled dam (BMSD) was constructed in a drought-prone area in South Korea, specifically in the Mullocheon catchment, to supply water to a small-population village. The BMSD was connected in series with an existing small pond, and the drainage rates were integrated through a single conduit. Quantitatively analyzing the contribution of the newly constructed sand-filled dam was challenging, so this study investigated the effect of the sand dam on water supply capacity using a bed-mounted infiltration system. The contribution of the sand-filled dam to the total drainage rate was calculated using observation data. New hydrological insights for the regionThe hydraulic conductivity of the riverbed and the drainage rate of the intake pond were estimated using the observed water level and flow rate. Prior to the installation of the sand dam, from January to May 2021, the total precipitation was approximately 284.72mm, and the average drainage rate was 76.78m³/d. After the sand dam was installed, from January to May 2022, the precipitation was 165.13mm, and the average drainage rate increased by 45.4% to 124.49m³/d. It was observed that during normal periods, the supply was more than three times greater than before, and even during droughts, the supply met the residents' needs. This indicates that the sand-filled dam’s storage effect has enhanced drought resilience.

Collaborative water-electricity operation optimization of a photovoltaic/pumped storage-based aquaculture energy system considering water evaporation effects

The increasing global population, economic development, and urbanization trends have led to a heightened demand for seafood, presenting a significant challenge to the growth trajectory of the food industry. As the most rapidly expanding segment within the food industry, aquaculture presents a sustainable solution to mitigate the overexploitation of marine resources and address the growing demand for food. Aquaculture's sufficient aquatic expanses offer considerable potential for PV deployment, thereby relieving the demand for limited land resources. However, existing research rarely addresses the collaborative operation of water and electricity in aquaculture systems. The effects of water evaporation from PV panel-covered water surfaces on the collaborative water-electricity operation are generally neglected. Hence, this work proposes a collaborative water-electricity operation of a photovoltaic (PV)-pumped storage-based aquaculture energy system considering the water evaporation effects. This optimization method accounts for the reduced water evaporation due to PV panel shading. Water surface PV and pumped storage are integrated into the system to fulfill electricity needs, with pumped storage serving as a dual-purpose device for water and electricity supply. Environmentally sustainable water-electricity generation and aquaculture energy system requirements are established. Water surface PV electricity generation is modeled based on climate and engineering conditions, while aquaculture pond electricity requirement includes oxygenation, feeding, and water replenishment. Finally, a collaborative water-electricity operation model is introduced to optimize operation strategies for various devices. A case study on a fish-light complementation project demonstrates that this optimization method can reduce reliance on the utility grid and overall system operational costs.

Key point of desert riparian forest development in the arid area: The response of phreatic water table depth to ecological water supply

Desert riparian forest vegetation maintains the fragile balance of ecosystems in extreme arid areas. Raising the phreatic water table through efficient ecological water supply is the key to the desert riparian forests in extreme arid areas. The main objective of this study is to explore an innovative framework in which the response of phreatic water table depth (PWTD) to ecological water supply flow (EWSF) can be effectively reflected. The framework is based on the computationally efficient integrated surface water - groundwater model (ISGWM), through which surface water processes, groundwater recharge and discharge processes, and PWTD changes under different EWSF can be accurately simulated. A large number of simulations were conducted to reflect the response of PWTD to EWSF, and to explore the suitable EWSF and its intra-annual process considering the efficiency of PWTD reduction. The applicability and advantages of ISGWM were evaluated for the Tarim River Basin (TRB), a typical inland river basin, northwest China. The response of PWTD to EWSF was studied in 55 gate control areas in the mainstream of TRB. The formulas of suitable EWSF of 55 gates with different initial PWTDs were fitted. It is more beneficial to concentrate the ecological water supply in flood season (Jun.-Oct.). Overall, the ISGWM can accurately describe the multi-process of surface water and groundwater interactions. This study can provide scientific support for water resources management and allocation in the TRB and other similar inland river basins.

Integrated geophysical and remote sensing/GIS interpretation for delineating the structural elements and groundwater aquifers of the Foumban locality, Western Highlands of Cameroon (WHC)

This study was conducted in the Foumban locality, in the Western Highlands of Cameroon (WHC) where a majority of the population is suffering from scarcity of water for domestic purposes and many other related uses. Thus, it aims at investigating the structural and geo-electrical characteristics of the aquifer system of the locality, based on an integrated approach (Geophysics and GIS). For this purpose, the Landsat 8 image with 30 × 30 m resolution and 20 vertical electrical sounding (VES) data were analysed with ArcGIS, ENVI version 5.3, Stereonet v9.3.2 and QWSELN software, coupled with the principal component analysis (PCA). Based on the structural aspect, a total of 224 fractures with lengths higher than 1 km have been identified and drawn. They are mainly grouped in the Centre, North-East and South-East of the study area. Five main families within linear directions have been identified: N10-20 (13.84%), N20-30 (17.86%), N50-60 (9.82%), N80-90 (5.90%) and N140-150 (7.59%). They are mostly oriented NE-SW, following the Cameroon Volcanic Line (CVL). These fractures which play an important role in the capacitive and drainage function of the fractured aquifer result from the tectonic movements and decompression of rock masses. According to the geoelectrical characteristics, different VES curve types have been identified, corresponding to various alternate layers of conductive, semi resistive and resistive formations; with thickness ranging between 0.41 to 47 m and resistivity values between 82 to 3410 Ωm. The three cross-section realised (A-A’, B-B’ and C-C’) show that those alternate materials (topsoil, laterite, weathered layer, fractured basement and fresh basement rock) are discontinuous both vertically and horizontally, highlighting the geometry and hydrogeological complexity of these areas. This study is a contribution to a better understanding of the basement aquifers milieu; it could be used by the water supply departments and decision makers for locating appropriate positions of new productive wells in the study area.

Numerical Simulation Study on Reverse Source Tracing for Heating Pipeline Network Leaks Based on Adjoint Equations

In order to identify the leak source in complex heating pipeline networks, a timely and effective simulation of the leakage process was conducted. The open-source computational fluid dynamics software OpenFOAM 5.0 was combined with the PISO algorithm to simulate the pressure during the leakage in water supply networks, transforming the reverse source tracing problem into the solution of an adjoint equation. The validation of the transient adjoint equation for single-phase flow was completed through simulation, and the pressure wave change graph at the moment of the network leakage was solved, which was consistent with the experimental results. Using the open-source finite element analysis software OpenFOAM 5.0, the positioning accuracy of pipeline leak points can be controlled within the range from 92% to 96%. Based on the pressure wave change graph, the position of the leak source in the complex network was determined using the reverse source tracing method combined with the second correlation theory. The results show that the calculation speed of the PISO algorithm combined with the adjoint equation is significantly better than that of the individual SIMPLE and PISO algorithms, thereby proving the superiority of the adjoint method.

Calla lily-inspired 3D evaporator: A dual interface design for enhanced solar water evaporation

Due to the exponential growth of the global population, groundwater resources have long been insufficient to meet the escalating demand for potable water. In recent years, interfacial solar stream generation (ISSG) technology has emerged as a pivotal approach in generating clean water. The paramount performance factors of solar thermal evaporators encompass their exceptional light absorption capacity, efficient water transport, and effective thermal management. Among these factors, the 3D interface evaporator stands out due to its inherent advantages and ingenious structural design that enhances overall performance. In this study, the structure of calla lilies was used as inspiration, we propose a novel design featuring a 3D inverted conical double-sided evaporator (3D-ASIE) which effectively traps sunlight within its core, thereby augmenting light absorption capabilities while simultaneously forming a dual-evaporation interface. The inverted conical structure comprises two cellulose/TiN aerogel films with superior light absorption and heat insulation properties along with a polytetrafluoroethylene (PTFE) hydrophilic film that is skillfully bent and assembled together. To ensure continuous water supply during evaporation, the tail end of the hydrophilic membrane is immersed in water. During interfacial evaporation process, activation of the outer photothermal layer of our 3D-ASIE facilitates steam diffusion along both inner and outer surfaces of the inverted cone structure concurrently resulting in an impressive dual-evaporative effect. Under sunlight intensity level at 1 kW m−2, our 3D-ASIE exhibits remarkable performance with an evaporation flux reaching up to 2.97 kg m−2 h−1 alongside an efficiency as high as 94.7 %, thus demonstrating immense potential for large-scale solar desalination applications.