Freshwater Supply Research Articles

Spatiotemporal Variations and Driving Factors of Water Availability in the Arid and Semiarid Regions of Northern China

It is anticipated that global warming will modify precipitation and evapotranspiration patterns, consequently affecting water availability. Changes in water availability pose challenges to freshwater supply, food security, and ecosystem sustainability. However, the variations and driving mechanisms of water availability in the arid and semiarid regions of Northern China remain unclear. This study evaluates the accuracy of three evapotranspiration products and analyzes the changes in water availability in the arid and semiarid regions of Northern China over the past 39 years (1982–2020) along with their driving factors. The results indicate that during this period, precipitation increased at a rate of 7.5 mm/decade, while evapotranspiration rose at a higher rate of 13 mm/decade, resulting in a decline in water availability of 5.5 mm/decade. Spatially, approximately 30.17% of the area exhibited a significant downward trend in water availability, while 65.65% remained relatively stable. Evapotranspiration is the dominant factor leading to the decrease in water availability, with a contribution rate of 63.41%. The increase in evapotranspiration was primarily driven by temperature (32.53% contribution) and the saturation vapor pressure deficit (24.72% contribution). The decline in water availability may further exacerbate drought risks in arid and semiarid regions. The research results can provide a scientific basis for developing water resource management strategies and ecological restoration strategies under environmental change.

A High‐Efficiency System for Long‐Term Salinity‐Gradient Energy Harvesting and Simultaneous Solar Steam Generation

AbstractThe vast energy stored in the ocean, which receives an average solar power of ≈60 000 TW per year, surpasses human energy consumption by three orders of magnitude. Harnessing even a small fraction of it holds great promise in addressing global energy and water crises. Here, an integrated device that achieves unprecedented power density up to 1.1 W m−2 with excellent stability through a salinity concentration gradient induced by solar evaporation, while simultaneously producing clean water at a rate of 1.25 kg m−2 h−1 under one sun irradiation is presented. The remarkable electricity generation capability stems from the unique interlayer structure of polyaniline‐graphene oxide‐MnO2 (PANI@GO/MnO2) electrodes, enabling the recovery of electrochemical potentials from a wide range of ion salinity concentrations within the device and the additional Donnan potential generated by the anion‐exchange membrane. Furthermore, periodic flipping of the device effectively reactivates the electrodes and suppresses salt accumulation, enabling long‐term operation. Notably, a prototype device of 8 × 25 cm2 exhibits a short‐circuit current of 10 mA and an open‐circuit voltage of 10.2 V, as well as a clean water production rate of 24.8 g per hour. These findings shed light on the reliable technology for power and freshwater supply in marine environments.

Exploring the Interactions of Climate Change, Freshwater Supply, and Environmental Balance

Climate change has far-reaching implications for global freshwater availability and environmental balance. The increase in greenhouse gases from the burning of fossil fuels has triggered global climate change, affecting precipitation patterns, glacier melt and sea level rise. Parts of the United States are experiencing significant changes in precipitation patterns, with some areas experiencing frequent storms and others experiencing more prolonged droughts. Accelerated glacier melt is leading to fewer water sources during the dry season, and sea level rise is threatening coastal freshwater resources, triggering saltwater intrusion and a decline in freshwater quality. Wildfires in California are an important consequence of climate change, severely affecting freshwater resources and environmental balance. Wildfires lead to reduced water resources, impacting agricultural water use and irrigation infrastructure, and affecting water quality through increased sediment and pollutant loads. The 2018 Camp Hill Fire contaminated local water sources, and the rebuilding process has increased demand for water resources, exacerbating resource constraints. Global warming has lengthened wildfire seasons and increased fire intensity, leading to increased pressure on freshwater resources. By analyzing the impacts of climate change on freshwater resources, this paper hopes to draw public attention to environmental protection and provide a reference for gradually optimizing ecosystems and creating a healthy living environment.

Geochemical evolution of the Dead Sea brine during the last glacial cycle from chemical compositions of interstitial soluble salts

The chemical evolution of the brines that filled the Dead Sea Basin during the final phase of the last interglacial and throughout the last glacial period is constructed from the temporal variations in the Na/Cl, Mg/Cl, Br/Cl, and Br/Mg ratios of soluble salts that extracted from cores that were drilled at the modern Dead Sea floor and from sediments of the last glacial Lisan Fm. that are exposed at the high terraces above the modern Dead Sea (covering the ∼ 100–13 ka period).The main observations are: (1) Variations in the Na/Cl ratios reflect processes of halite precipitation/dissolution during arid/wet periods in the drainage basin, respectively, and exchanges between the upper and the lower brines; (2) Ions of Na + and Cl-were supplied to the brines by the dissolution of halite from the Mount Sedom salt diapir, and of halite deposits, which precipitated in the lake during the hyper-arid periods of the last interglacial; (3) The upper brine of Lake Lisan was sensitive to the hydroclimatic conditions in the lake’s drainage basin, since being directly exposed to the atmosphere, and to variations in flows of freshwater and groundwater brines, which had distinct influence on its chemical record. At the same time, the lower brine was isolated from the surroundings, by the overlying brine and received chemical inputs only by restrict mixing between the brines which buffered the intensity of regional hydro-climatic events.Temporal patterns in the Na/Cl ratios indicate that between ∼ 100–30 ka, the deep brine evolved through a moderate but steady “enrichment” by Na + and Cl-ions due to continuous dissolution of halite by the upper brine of the lake. Towards the end of this period, between ∼ 43–30 ka, the Amiaz plain, a marginal basin, comprised a semi-isolated water-body that witnessed frequent episodes of halite precipitation/dissolution with temporal patterns that resemble millennial temperature (δ18O) variations in the Greenland ice core.Between ∼ 30–18 ka (MIS 2), when Lake Lisan reached its highest stands and maximumspatialexpansion, the soluble salts from the deepest basin and from the high sections of the Lisan Fm. indicate on centennial dissolution cycles of the Mount Sedom salt diapir that took place in the upper brine and sank down to the lower brine. During the ∼ 18–14 ka decline of the lake to its low levels of the Holocene, the elemental ratios reveal several episodes of enhanced supply of freshwater to the shrinking lake, causing intensified halite dissolution and supply of Na + and Cl- ions to the deep basin, setting the grounds for massive halite precipitation, which initiated after a sharp level decline at ∼ 14 ka.The long-term (∼100–13 ka) temporal pattern in the elemental ratios of the lower brine resembles global CO2concentrations and sea surface temperature trends, while the short-term fluctuations in the upper brine are correlated with short warm/cold cycles in the Greenland ice core δ18O data, indicating a strong impact of the global climate.

Hofmeister effect induced water activation of hydrogel and its applications for the accelerated solar evaporation in brine

Solar-driven desalination has emerged as a promising approach to address water scarcity caused by the decreasing supply of freshwater. Reducing the enthalpy of water vaporization is crucial for enhancing the efficiency of solar-powered desalination. In this study, inspired by the Hofmeister effect, we developed a highly hydratable network hydrogel evaporator to achieve a superior evaporation rate in brine compared with pure water. The evaporator comprised a carbonized layer as the photothermal layer and a chitosan aerogel hydrogel as the hydratable matrix. The hydrogel exhibited a dramatically reduced vaporization enthalpy of 1397 J/g and a significant evaporation rate of 2.38 kg m−2 h−1 when exposed to seawater. These results demonstrated the superior performance of hydrogel compared with pure water (1.91 kg m−2 h−1). Excellent evaporation rates and outstanding salt resistance ensured efficient coordination for practical long-term desalination applications. Further investigations revealed that the remarkable evaporation performance of the carbonized chitosan (CCS) hydrogel in brine environments was attributed to its hydrability, which was regulated by Cl−. According to the Hofmeister effect, Cl− accelerated the hydration chemistry in CCS and suppressed the associated crystallinity, which resulted in a lower enthalpy of vaporisation owing to a higher amount of intermediate water. With its superior evaporation performance in brine and comprehensive theoretical simulation analysis, this study presents an achievable and economical strategy for simultaneously addressing the water and energy crises.

Potential impact of climate change on water productivity and water footprints of rice and wheat in the Indo-Gangetic plains of India.

Agriculture faces a significant problem as a result of the decline in per capita freshwater supply that has been observed over the past couple of decades. Better water management strategies are required in order to make agriculture water secure, environmentally sustainable, and economically attractive. The goal of this study was to develop water productivity scenarios for rice and wheat crops in India's Indo-Gangetic Plain (IGP) by analysing agricultural production from the perspective of water consumption. To pinpoint the areas that are hydrologically suitable for growing rice and wheat crops under RCP4.5 and RCP8.5 climate change scenarios, water footprints and water productivity have been mapped. The study found that changes in temperature trends under future climate scenarios are probably going to increase crop water requirements, leading to greater water footprints for IGP regions. Water risk hotspots have been identified in the IGP for the rice- and wheat-growing states of Uttar Pradesh, Punjab, and Haryana. In order to achieve food security in a sustainable way, attention should be given to increase the water productivity of both crops.

Performance simulation of solar-driven absorption heat pump-membrane distillation system for combined desalination brine concentration with feed recirculation and cooling applications

Desalination is the primary choice for securing freshwater provision in water-stressed regions and reduces the gap between rising demand and dwindling natural freshwater resources. However, global desalination plants are dominated by fossil fuel-driven desalination technologies with a 40–50 % recovery ratio. Hence, it is critical to decarbonize desalination and address brine effluent ecological concerns. In this paper, a solar-powered absorption heat pump (AHP)-membrane distillation (MD) system concept was proposed and analysed for small-scale RO plant brine reject management and space cooling applications. The MD subsystem is based on commercial MD modules with batch feed recirculation to reach saturation (from 70 to 260 g/kg salinity). The MD system's heating and cooling consumptions are supplied by the AHP (6.54 MWh and 13.47 MWh, respectively, for a complete batch cycle). The AHP is designed to supply hot water at 85 °C with 701.63 kW heating capacity and co-produced chilled water at 16 °C with a cooling capacity of 857.86 kW, about 67 % is utilized to cool down the brine reject to feed temperature. The thermal and exergy COPs were 1.273 and 0.40 at a driving heat of 135 °C. The solar-powered AHP-MD system is useful for sustainable desalination deployment besides space cooling applications.

Influence of Longitudinal Fragmentation on Length–Weight Relationships of Fishes in the Someșul Cald River, Romania

Romania has a rich hydrographic network, which permitted the construction of over 80 large dams on its water courses, estimating a number between 545 and 674 hydropower plants that were either built or were in a different construction stage on the rivers of Romania in 2021. These hydropower plants were often built outside specific legislation regarding ecological impacts, especially before 1990. Longitudinal fragmentation of rivers causes severe ecological impacts on biodiversity, food chains, and nutrient cycles. Someșul Cald River is the main tributary of Someșul Mic River, the most important water source for the northwestern region of Transylvania. On its course, several dams and reservoirs were built from 1968 to 1980 for electricity production and population freshwater supply. The present study aimed to analyze the length–weight relationships (LWRs) and condition factors occurring in the longitudinally fragmented Someșul Cald River. The LWRs, relative condition factor Kn, and Fulton condition factor K were determined based on total length and wet body weight. Comparisons of LWRs, Kn, and K across river sections constrained by dams showed that some fish species exhibited similar growth patterns and physiological conditions, while others differed significantly. Freshwater fish physiology is altered by longitudinal fragmentation, both natural and artificial. Barriers such as dams influence the energy gradient, limiting feed availability and, consequently, the life history of fish species. Long-term management plans regarding conservation should take into consideration existing fish species population dynamics, along with their physiological and somatic status.

Simulation of a Tidal Current-Powered Freshwater and Energy Supply System for Sustainable Island Development

Sustainable development of islands cannot be achieved without the use of renewable energy to address energy and freshwater supply issues. Utilizing the widely distributed tidal current energy in island regions can enhance local energy and water supply security. To achieve economic and operational efficiency, it is crucial to fully account for the unique periodicity and intermittency of tidal current energy. In this study, a tidal current-powered freshwater and energy supply system is proposed. The marine current turbine adopts a direct-drive configuration and will be able to directly transfer the power of the turbine rotation to the seawater pump to improve the energy efficiency. Additionally, the system incorporates batteries for short-term energy storage, aimed at increasing the capacity factor of the electrolyzer. A simulation is conducted using measured inflow velocity data from a full 12 h tidal cycle. The results show that the turbine’s average power coefficient reaches 0.434, the electrolyzer’s average energy efficiency is 60.9%, the capacity factor is 70.1%, and the desalination system’s average specific energy consumption is 6.175 kWh/m3. The feasibility of the system design has been validated.

Sun-powered solutions: Investigating productivity and economics of small-scale solar desalination system

Freshwater demand is one of the most critical challenges facing many countries in the world. Jordan is a country in the middle east that is considered one of the poorest countries for renewable freshwater supplies in the world. Though desalination may be one of the solutions to the problem, the cost and energy expenses could be an obstruction. However, with an abundance of annual solar irradiance in Jordan, solar desalination systems, particularly small-scale ones, are considered better alternatives. In this study, a residential-scale solar desalination system is investigated. The design includes evacuated-tube solar heaters with a heat pipe, and flashing units comprising three desalination stages. The experiments included single-stage, double-stage, and triple-stage desalination. The results showed that production rates of 2.2 kg/m2 using single-stage, 4.7 kg/m2 using double-stage, and 6.4 kg/m2 using triple-stage desalination were obtained from the system. The solar water heater used in the system exhibited an average thermal efficiency of 73 %. The economic analysis revealed that the payback period for the triple-stage desalination system is 8 years. The annualized rate of return was calculated to be 2.2 %, assuming the system operates for 4 h per day and 300 days per year.

A Review of Renewable Energy Powered Seawater Desalination Treatment Process for Zero Waste

Freshwater resources have faced serious threats in recent decades, primarily due to rapid population growth and climate change. Seawater desalination has emerged as an essential process to ensure a sustainable supply of freshwater to meet the global demand for freshwater. However, this approach has some shortcomings, such as the disposal of brines containing high levels of contaminants creating environmental problems, and the energy-intensive nature of desalination, primarily powered by fossil fuels, which contribute to greenhouse gas emissions. Consequently, as a solution, the zero liquid discharge approach has been identified by the body of research to be one of the viable methods to solve these problems. Over 90% of freshwater and reusable salts could be recovered through this approach. Adopting renewable energy-powered systems could make zero-liquid discharge desalination plants operate in an entirely environmentally friendly and sustainable manner. This review explores the integration of renewable energy-powered systems for the optimisation of seawater desalination treatment processes for zero-waste and improved productivity. The review also examines technologies and strategies that improve the efficiency and sustainability of desalination systems. By analysing recent research, we provide insights into the advancements, challenges, and prospects for optimizing renewable energy-powered seawater desalination processes aimed at achieving zero waste.

Municipal-treated wastewater as a practical alternative to conventional rice irrigation: Effects on antibiotic resistance genes, virulence factors and human bacterial pathogens in soil, and responses of rice grain quality

Reuse of municipal-treated wastewater for agricultural irrigation is becoming increasingly prevalent due to growing demand and decline in freshwater supplies. However, the microbial contamination profile, including antibiotic resistance genes (ARGs), virulence factors (VFs), and human bacterial pathogens (HBPs) in agricultural soil irrigated with municipal-treated wastewater for paddy cultivation, was unknown. Here, metagenomic analysis was applied to provide a systematic insight into the resistome, VFs and HBPs in paddy soils irrigated with municipal-treated wastewater. The obtained results revealed that the residual antibiotics in municipal-treated wastewater has an impact on the antibiotic resistome by increasing both the total number and abundance of ARGs. Furthermore, it was found that sul1 could serve as a potential risk indicator for assessing ARG contamination. VFs, core HBP abundance, and dangerous pathogens remain unaffected by municipal-treated wastewater irrigation for paddy. The good coexistence patterns of ARGs-HBPs and ARGs-VFs demonstrated the presence of resistant pathogenic bacteria. The network analysis revealed that ARGs-bearing Legionella pneumophila, Mycobacterium marinum, Bordetella pertussis, Staphylococcus aureus, and Pseudomonas aeruginosa might be ranked as high-risk HBPs. Additionally, our investigation also demonstrated that reuse of municipal-treated wastewater for agricultural irrigation had no detrimental effects on rice plant growth and grain quality. This study was the first to investigate the response of VFs and HBPs in paddy soil under long-term municipal-treated wastewater irrigation. The obtained results provide a scientific basis for the safe application of municipal-treated wastewater.

An efficient water quality index forecasting and categorization using optimized Deep Capsule Crystal Edge Graph neural network.

The world's freshwater supply, predominantly sourced from rivers, faces significant contamination from various economic activities, confirming that the quality of river water is critical for public health, environmental sustainability, and effective pollution control. This research addresses the urgent need for accurate and reliable water quality monitoring by introducing a novel method for estimating the water quality index (WQI). The proposed approach combines cutting-edge optimization techniques with Deep Capsule Crystal Edge Graph neural networks, marking a significant advancement in the field. The innovation lies in the integration of a Hybrid Crested Porcupine Genghis Khan Shark Optimization Algorithm for precise feature selection, ensuring that the most relevant indicators of water quality (WQ) are utilized. Furthermore, the use of the Greylag Goose Optimization Algorithm to fine-tune the neural network's weight parameters enhances the model's predictive accuracy. This dual optimization framework significantly improves WQI prediction, achieving a remarkable mean squared error (MSE) of 6.7 and an accuracy of 99%. By providing a robust and highly accurate method for WQ assessment, this research offers a powerful tool for environmental authorities to proactively manage river WQ, prevent pollution, and evaluate the success of restoration efforts. PRACTITIONER POINTS: Novel method combines optimization and Deep Capsule Crystal Edge Graph for WQI estimation. Preprocessing includes data cleanup and feature selection using advanced algorithms. Deep Capsule Crystal Edge Graph neural network predicts WQI with high accuracy. Greylag Goose Optimization fine-tunes network parameters for precise forecasts. Proposed method achieves low MSE of 6.7 and high accuracy of 99%.

Experimental study based on the usage of polymers for greywater treatment

Water scarcity presents a pressing challenge in Egypt, exacerbated by factors such as population growth, urbanization, and climate change impacts. With over 95% reliance on the Nile River for freshwater supply, Egypt's water resources are strained, particularly with a population exceeding 100 million. Egypt's arid climate intensifies water scarcity, necessitating sustainable management strategies. This study explored greywater treatment as a solution to alleviate water scarcity in Egypt, investigating its technical feasibility, economic viability, and environmental benefits. Greywater, derived from domestic activities, is an underutilized resource that can be reclaimed and treated for reuse, reducing demand for freshwater sources. Through greywater treatment systems, households and communities can recycle water, conserve resources, and mitigate pollution. The study investigated using polymers as a coagulant in greywater treatment, examining its efficacy in removing contaminants and improving water quality. Experimental trials were conducted to evaluate the performance of polymer addition in greywater treatment compared to conventional methods. Results demonstrate that polymer addition reduces turbidity, suspended solids, and organic pollutants in greywater. Poly aluminum chloride (PAC) polymer, in particular, exhibits strong coagulation capabilities, versatility across pH ranges, and high efficiency in contaminant removal. Additionally, PAC offers operational advantages such as low dosage requirements and reduced sludge production.

Beyond the Wedge: Impact of Tidal Streams on Salinization of Groundwater in a Coastal Aquifer Stressed by Pumping and Sea‐Level Rise

AbstractSaltwater intrusion (SWI) is a well‐studied phenomenon that threatens the freshwater supplies of coastal communities around the world. The development and advancement of numerical models has led to improved assessment of the risk of salinization. However, these studies often fail to include the impact of surface waters as potential sources of aquifer salinity and how they may impact SWI. Based on field‐collected data, we developed a regional, variable‐density groundwater model using SEAWAT for east Dover, Delaware. In this location, major users of groundwater from the surficial aquifer are the City of Dover and irrigation for agriculture. Our model includes salinized marshland and tidal streams, along with irrigation and municipal pumping wells. Model scenarios were run for 100 years and included changes in pumping rates and sea‐level rise (SLR). We examined how these drivers of SWI affect the extent and location of salinization in the surficial aquifer by evaluating differences in chloride concentration near surface waters and the subsurface freshwater‐saltwater interface. We found the presence of the marsh inverts the typical freshwater‐saltwater wedge interface and that the edge of the interface did not migrate farther inland. Additionally, we found that tidal streams are the dominant pathways of SWI at our site with salinization from streams being exacerbated by SLR. Our results also show that spatial distribution of pumping affects both the magnitude and extent of salinization, with an increase in concentrated pumping leading to more intensive salinization than a more widely distributed increase of the same total pumping volume.

Optimizing sustainable multiple biomass-to-biofuel conversion network with integrated water resource management utilizing data-driven robust planning

Until now, the biofuel supply chain has lacked an integrated approach to address its fundamental challenges in real-world implementation. The first challenge is maintaining a continuous supply flow in the biofuel network, which can significantly impact economic outcomes and performance measures. The second challenge involves managing water resources for biofuel production to preserve freshwater reserves. The third challenge is managing operational risks, such as uncertainty in biofuel demand, which leads to conservative planning and underscores the need for realistic uncertain programming approaches. To address these challenges, the proposed study designs a biofuel conversion network that utilizes third-generation feedstocks and non-edible seed sources, sourcing necessary water from wastewater resources. This practical solution addresses water-energy relationship concerns, reducing dependency on limited freshwater supplies. To achieve a continuous and cost-effective feed supply, this study incorporates a pre-processing phase using a hybrid Multi-Criteria Decision-Making model. This approach ensures the feed supply remains consistent, economical, and sustainable. To manage the uncertainty in biofuel demand, we developed a robust optimization model with an intersected uncertainty set using a data-driven approach. This approach aims to reduce conservatism in the obtained solutions, making the model more practical for real-world implementation. The numerical results reveal some practical implementation for policymakers. The proposed robust optimization using the configured uncertainty set offers a tool to manage the conservatism of renewable energy demand uncertainty and operational risks more effectively than traditional approaches (0.914%). This formulation can help policymakers to maintain greater robustness against fluctuations in confidence levels. Additionally, the simultaneous use of third-generation and non-edible feedstocks creates a multi-biomass-to-biofuel conversion network, offering practitioners a practical solution that significantly reduces reliance on freshwater resources. Furthermore, policymakers can leverage the proposed pre-processing phase to promote economic and continuous supply feed based on geographical, resource accessibility, and infrastructure criteria.

Isotope characterisation of groundwater resources in uranium impacted Fazilka, Punjab

AbstractGroundwater is the most reliable source for freshwater supplies in India and abroad. Population rise has affected the groundwater resources both in terms of quality and quantity. Punjab, being an agrarian state, is highly dependent on groundwater resources for both irrigation and drinking purposes. Recent studies have indicated presence of uranium in groundwater especially in southwestern parts of Punjab. In this research, water samples were collected from Fazilka district of Punjab for evaluating the water quality focussing uranium and identifying source and recharge processes of groundwater. Uranium concentration was found in both shallow and deep groundwater samples. Inter-ionic correlations signify that alkalinity and electrical conductivity of the water samples control the uranium mobilization from the aquifer matrix. Isotopic systematics demonstrate that groundwater recharge is mainly through rainwater infiltration.

Simulating the emergence of institutions that reverse freshwater salinization: An agent-based modeling approach

Salt concentration in global freshwater supplies has increased steadily, leading to the Freshwater Salinization Syndrome (FSS). To curb the FSS, stakeholders can self-organize to develop institutions, or a set of rules that limit salt emissions. This research develops an agent-based modeling framework to explore how institutions reverse the FSS. Property owners are represented as agents that apply rules of behavior to apply salt to deice pavement in response to winter weather, vote on institutions, and comply with or defect from institutions. Salt enters the soil-groundwater system through infiltration, which is modeled using a transit time distribution approach. Results demonstrate that stable institutions lead to positive economic outcomes for stakeholders, based on their ability to apply salt during winter events and access high-quality drinking water. Simulations are analyzed to explore institutions, or limits to the application of salt, that emerge based on the interactions of stakeholders as they agree on salt application limits, the intensity of monitoring for defectors, and sanctions. Institutions that emerge effectively limit the concentration of salt in drinking water. The emergence of stable institutions low rates of innovation among stakeholders, and the concentration of salt in groundwater exceeds standards due to high rates of defection among stakeholders. This research demonstrates how self-organized institutions can lead to sustainable application strategies that reverse the FSS.

Technological aspects of growing commercial trout on the basis of IP «Ak Balyk»

The materials for the preparation of the article were based on samples and observations taken at the stage of entering the IP "white fish".Research on this topic was carried out using hydrochemical methods, production technologies and evaluation of fish products.As a result of the study, it was found that:1. A fish pond with an area of 1.2 hectares, an average depth of about two meters with a fresh water supply of 16 liters/ sec.2. A basin area with a total water volume of 985.8 m3 and a water exchange rate of 46 l/sec, for commercial trout cultivation.There are no sources of anthropogenic impact and factors negatively affecting the ecology of the environment in the fish farming area of IP "Ak Balyk".According to hydrochemical indicators, the water on the farm meets the requirements for fish farming.

3D‐Shape Recoverable Hydrogel with Highly Efficient Water Transport for Solar Water Desalination

AbstractPorous hydrogels have been developed to be highly efficient interfacial solar vapor generation materials for obtaining affordable freshwater supplies. However, realizing hydrogel materials with portability, adequate water supply, and durable mechanical properties remains challenging. Herein, a scalable and portable hydrogel with 3D‐shaped recovery, highly efficient water transport, and robust mechanical stability is reported, which is prepared by foaming polyvinyl alcohol (PVA) and modification of phosphotungstic acid (PTA). Due to the interconnected porous structure and highly permeable polymer network, the PVA/PTA‐PH hydrogel has good repetitive compressibility and rapid shape recovery when in contact with water. Combined with light‐absorbing nanoparticles, the PVA/PTA‐PH hydrogel presents an impressive solar evaporation rate of 3.876 kg m−2 h−1 and a photothermal conversion efficiency of ≈94% under 1‐sun irradiation. With 3D‐shape recovery and highly efficient water transport, the compressed hydrogel can be quickly unfolded without human intervention and restored to five times the original size for the working state. The good portability, excellent seawater desalination performance, and simple preparation process are anticipated to make the PVA‐/PTA‐PH hydrogel a promising material to continuously and conveniently produce pure water from seawater.