Volume Of Water Research Articles

An effective aeration system for high performance pond aeration at low energy cost

AbstractWith the effective use of aerators with low energy cost and high aeration performance, aquaculture areas can be developed and supported. The main objective of this study is to determine the optimal physical parameters of high aeration capacity high head conduits and to ensure low energy costs, thus to present a comprehensive review of its usability for pond aeration. In this study, a high-head gated conduit was used as the aeration unit. After obtaining the design that will maximize the aeration performance of the high-head gated conduit, a prototype model was developed to ensure its effective use in pond aeration. The parameters affecting the performance of this developed aeration system and the corresponding energy cost values were determined. According to the results, the most important parameters affecting the aeration performance are, respectively, flow rate, the opening of the gate, hydrostatic level, and jet plunge angle. In the optimal design, more than three times the unit volume of water circulating in the system is added to the system. The cost value of this operation in terms of energy was measured as 0.10 kWh/m3 air. The developed system was found to have significantly higher energy efficiency values compared to alternatives, based on specific energy consumption data.

Evaluation of sulfate rhizofiltration by Carpobrotus chilensis for treating mining waters

Chile, the world’s leading copper producer, generates significant volumes of mining waters, some of which cannot be recirculated into the production process. These mining waters are characterized by elevated sulfate ( SO 4 2 − ) concentrations, requiring sustainable management strategies for potential reuse. This study aims to evaluate the rhizofiltration technique using Carpobrotus chilensis for treating mining waters with a high SO 4 2 − concentration. Initially, the mining waters exhibited a pH of 7.97 ± 0.16 and a SO 4 2 − concentration of 2,743 ± 137 mg L−1, while the control water had a pH of 7.88 ± 0.08 and a SO 4 2 − concentration of 775 ± 19.0 mg L−1. The plants were hydroponically cultivated in 40 L containers with mining waters and drinking water as a control. Over an 8-week period, the pH of the mining water decreased to 3.12 ± 0.01, and the SO 4 2 − concentration declined to 2,200 ± 110 mg L−1. Notably, the fresh weight of roots was significantly higher in plants grown in mining water (22.2 ± 6.66 g) compared to those in the control treatment (14.3 ± 4.28 g). However, an undesirable increase in the acidity was observed in the mining waters after rhizofiltration, which was attributed to hydrogen sulfate (HSO4 -) and/or root exudates. Despite the unexpected increase in acidity, C. chilensis effectively reduced the concentration of SO 4 2 − in mining waters by 20%. Additionally, the C. chilensis roots accumulated 4.84 ± 1.40% of sulfur (S), a level comparable to thiophore plants. This study provides evidence that this non-aquatic plant can be used in sulfate rhizofiltration.

Water productivity at two sowing dates of simple white grain maize hybrids

In Mexico, maize stands out for its economic, food and cultural importance. Since ancient times, attempts have been made to increase maize grain yields with different alternatives, including hybridization. Currently, maize hybridization offers great advantages since from the first simple hybrids it is possible to evaluate important variables such as water productivity. The present work was carried out under field conditions in southern Sonora, in two sowing seasons: December 2022- May 2023 (SD 1) and April-August 2023 (SD 2). The research aimed to evaluate the effect of two sowing dates (SD) on phenology, water requirements, water productivity and grain yield. Three single white grain hybrids (L5 X L7; L1 X L2; L2 X L7) obtained from a dialelic design were evaluated. Phenophase occurrence time, irrigation time and interval, total water volume, evapotranspiration, grain yield and water productivity were the evaluated variables. The results showed that in SD 2 significantly reduced the time of occurrence of phenophases in all hybrids due to the effect of temperature. Irrigation time was significantly shorter in SD 2 compared to SD 1. Similarly, the irrigation interval decreased in SD 2 compared to SD 1 with a significant increase in the irrigation lamina. It was necessary to apply two more irrigations to achieve grain filling. Water productivity showed highly significant differences between hybrids and between sowing dates. The simple hybrid L5 X L7 showed better agronomic performance on both sowing dates, demonstrating tolerance to the increase in temperature on SD 2.

Simulation of the use of rainwater in two schools in the public municipal education network in Aracaju-SE

With an increasing frequency periods of intense water scarcity are recorded in various parts of the planet. A measure that can be very efficient, is using rainwater, preserving potable water for use where it is needed, and contributing to the fight against urban floods. Considering the foregoing, this article aims to capture’s simulation and use of rainwater in two schools of the public municipal education network of Aracaju-SE, through the estimation of non-potable demand, estimation of the catchable volume, verification of the attendance of the estimated non-potable use and the impact of this action on the urban drainage system. Based on the roof area and the average’s data of precipitation, the volume of water captured by the roof was calculated, and finally, a demand for non-potable use was estimated, verifying if this demand is attended, in addition, the impact generated on the local urban drainage system was analyzed. The results indicate that: a) The Oviedo Teixeira School had an average demand of 258 m³, an average catchable volume of 326 m³ and an average reduction of 66% in the volume thrown into the drainage; b) The Anísio Teixeira School had an average demand of 60 m³, an average catchable volume of 140 m³, and an average reduction of 53% in the volume thrown into drainage. It is concluded that rainwater totally meets the estimated demand and rainwater harvesting positively impact on the drainage system, if used on a large scale.

Is water replenishment an effective way to improve lake water quality? Case study in Lake Ulansuhai, China

Lakes are an important component of the global water cycle and aquatic ecosystem. Lake water quality improvement have always been a hot topic of concern both domestically and internationally. Noncompliant outflow water quality frequently occurs, especially for lakes that rely mainly on irrigation return flow as their water source. External water replenishment to improve the water quality of lakes is gradually being recognized as a promising method, which however, is also a controversial method. Lake managers, in the case of constant controversy, hesitate about the appropriateness of lake water replenishing. Thus, taking Lake Ulansuhai in China as an example, this study aimed to construct a lake hydrodynamic and water quality model, under the constraint of multiple boundary conditions, that has sufficient simulation accuracy, and to simulate and analyze the changes in COD (Chemical Oxygen Demand) and TN (Total Nitrogen) concentrations in the lake area before and after water replenishment, and explore whether water replenishment was an effective method for improving lake water quality. The results showed that when the roughness value of Lake Ulansuhai was 0.02, the TN degradation coefficient K was 0.005/d, and the COD degradation coefficient K was 0.01/d; the simulation and measured values had the best fit, and the built model is reasonable and reliable can be used to simulate lake water quality changes. By external water replenishment lasting 140 days in the water volume of 4.925 × 108 m³, the COD and TN concentrations in Lake Ulansuhai could be stabilized at the Class V water quality requirement, which helped improve the self-purification ability of the lake area. Water replenishment was proved to be an effective method for improving the water quality of the lake, but water replenishment is only an emergency measure. Lake water replenishment is more applicable to areas with abundant water resources. External source control and internal source reduction of lake pollution and protection of lake water ecology are the main ways to improve lake water quality for water-deficient areas under the rigid constraints of water resources. In the future, key technologies for reducing and controlling pollution in irrigation areas, construction of lake digital twin platforms, and active promotion of lake legislation work should be the main research direction for managing the lake water environment.

Assessing irrigation impact on water quality conditions: A case study in the River Noguera Ribagorçana (NE Spain)

The need to feed an increasing population while limiting the environmental impact of agriculture is currently one of the greatest challenges relating to the food chain. One of the key factors involved in doing this is irrigation, which has a downstream impact that can be minimised if nutrient and water management are efficiently undertaken. The objective of this study was to determine which irrigation management improvements can be done at field scale in modern irrigated areas to reduce its irrigation return flow impact. The study was conducted in the Noguera Ribagorçana River basin, in NE Spain, where almost 6000 ha of land were brought into irrigation from 2000 to 2009. We based our study on a water quality dataset, measured in four different sites along a 29 km2 stretch of the river over a period of 20 years. Our results show an increase in nitrate (from 1.7 mg·L−1 to 10.5 mg·L−1) and salt concentrations (electrical conductivity from 297 to 675 µS·m−1) in the downstream course of the river compared to the most upstream monitoring site. That was exclusively associated with the irrigation return flows from the newly irrigated area. The highest nitrate and salt concentrations are found during the non-irrigation season which corresponds to the local rainy season. To reduce this impact, better irrigation management is required. Autumn leaching could be lowered by reducing irrigation volume applied during the final weeks of crop cycles in order to allow the soil to retain the volume of water received from rainfall. To deal with this issue, we propose a methodology based on soil moisture to determine the end of the irrigation season. In this way, the impact on ecosystems located further downstream would be reduced while crop yields and productivity in the area could be maintained.

A robust decision-making framework to improve reservoir water quality using optimized selective withdrawal strategies

In arid locations such as Oman, improving the quality of water released from a reservoir can be daunting. This is particularly true for Wadi Dayqah Dam, which struggles to provide sufficient, high-quality water for downstream needs. The study's objective was to establish more reliable operational guidelines, as well as identify vulnerable outlets and release ratios. To do so, a multi-objective optimization algorithm (NSGA-II) was combined with a selective withdrawal approach, using CE-QUAL-W2 and an Artificial Neural Network to simulate water quality in a reservoir. Then, a Robust Decision Making (RDM) approach was utilized to diagnose solutions that maintain acceptable water quality according to users’ requirements. Finally, scenario discovery models (Patient Rule Induction Method (PRIM) and Classification and Regression Tree (CART)) were used to calculate vulnerable outlets and release ratios based on the established threshold. The study adopted an XLRM framework to manage a proposed model under climate change scenarios and specify the effects of involved factors. XLRM stands for eXogenous factors, Levers used by the policy-makers, Relationships between L and X, and Measurement matrix to evaluate scenarios. This study found that a higher-quality reservoir release correlated with more activated outlets and decreased pollutant concentration. Evaluating robust solutions showed that vulnerability increased under scenarios with lower annual rainfall, and water released from low and mid-level outlets was more vulnerable than that from the surface. To enhance operational stability and reduce vulnerability, the suggestions advocate for a strategic approach in releasing varying water ratios from outlets situated at different levels. Specifically, the proposal emphasizes the controlled release of both smaller and larger volumes of water from outlets positioned at lower and higher levels within the dam structure, respectively. This deliberate variation in water release aims to bolster the overall resilience of the operational framework, contributing to a more robust and reliable system.

White Matter Microstructure Analysis in Subjective Memory Complaints and Cognitive Impairment: Insights from Diffusion Kurtosis Imaging and Free-Water DTI.

Dementia is characterized by a cognitive decline in memory and other domains that lead to functional impairments. As people age, subjective memory complaints (SMC) become common, where individuals perceive cognitive decline without objective deficits on assessments. SMC can be an early sign and may precede amnestic mild cognitive impairment (MCI), which frequently advances to Alzheimer's disease (AD). This study aims to investigate white matter microstructure in individuals with SMC, in cognitively impaired (CI) cohorts, and in cognitively normal individuals using diffusion kurtosis imaging (DKI) and free water imaging (FWI). The study also explores voxel-based correlations between DKI/FWI metrics and cognitive scores to understand the relationship between brain microstructure and cognitive function. Twelve healthy controls (HCs), ten individuals with SMC, and eleven CI individuals (MCI or AD) were enrolled in this study. All participants underwent MRI 3T scan and the BNI Screen (BNIS) for Higher Cerebral Functions. The mean kurtosis tensor and anisotropy of the kurtosis tensor showed significant differences across the three groups, indicating altered white matter microstructure in CI and SMC individuals. The free water volume fraction (f) also revealed group differences, suggesting changes in extracellular water content. Notably, these metrics effectively discriminated between the CI and HC/SMC groups. Additionally, correlations between imaging metrics and BNIS scores were found for CI and SMC groups. These imaging metrics hold promise in discriminating between individuals with CI and SMC. The observed differences indicate their potential as sensitive and specific biomarkers for early detection and differentiation of cognitive decline.

Unveiling the role of membrane properties in water and salt transport and performance of a concentration gradient battery

The concentration gradient battery (CGB) has numerous advantages, such as zero pollution emissions and the use of non-toxic electrolytes, making it a promising candidate for integrating renewable energy into the power grid. The use of high-performance membranes is a necessary condition for the application of CGB, but the specific membrane characteristics that contribute to desired CGB performance have not been clearly defined. In this study, five commercial membranes were employed to investigate the relationship among membrane permeation of water and salt, stack resistance, and battery performance. The results highlighted the pivotal roles of membrane permeability and resistivity in determining the CGB performance. Among the membrane tested, Selemion, notable for its low permeability and resistivity, was found to effectively break the trade-off between current and voltage efficiency. This superior performance is attributed to its distinctive membrane properties of low water volume fraction and high fixed charge density. This study further suggested that strategies aimed at controlling membrane swelling and increasing fixed charge density hold great promise in enhancing the membrane performance in CGB application. This research provides insights into membrane selection and customization for CGB and serves as a reference for other membrane processes focused on energy conversion.

Simultaneously removal of PAHs from contaminated soil and effluent by integrating soil washing and advanced oxidation processes in a continuous system: Water saving, optimization and scale up modeling

Every year a large amount of clean water turns into contaminated effluent by soil washing (SW) process. The release of this effluent has become a growing environmental threat. In this study, a sustainable approach was developed for effective removal of PAHs from contaminated soil and the effluent by integrating SW and advanced oxidation processes (AOPs) in a continuous system. In the constructed continuous system, first small amount of clean water passed through the contaminated soil to remove PAHs. Then, the polluted effluent was treated by a quick AOPs and recycled for SW processes again and again until a complete removal of PHE be achieved. The performance of the continuous system was optimized and compared with batch system (no circulation) at lab scale. In addition, a scale up modeling was developed to predict the performance of continuous system at large scale. According to the results, under the optimum conditions: Tween 80 (TW80) = 6 g/L, ultrasonic = 160 kW, UV = 30 W, O3 = 5 g/h and TiO2 = 2 g/m2, the final PHE degradation efficiency of 98 % and 94 % were achieved by the continuous and batch systems after 130 and 185 min, respectively. The continuous system used 5 times less water volume than the batch system but resulted in better PAHs degradation. The scale up modeling revealed at large scale (100 kg soil), the continuous system could decrease the energy consumption and the required washing solution (water + TW80) up to 50 % and 80 %, respectively in comparison to the batch system. This work suggests a promising and practical approach for contaminated soil remediation without producing polluted water.

Note on volume and distribution of fresh water in the Amazon River plume under low discharge conditions

In this research communication, we report the results of a field survey conducted in a part of the plume of the Amazon River between 0° and 5°N and offshore of the 28 m isobaths in November of 2022, during the low river discharge season. By comparing the observed vertical salinity profiles ‘disturbed’ by continental discharges within the plume with the virtually ‘undisturbed’ ones outside the plume, we estimated the total content of fresh water in the area covered by the measurements as 203 ± 22 km3, which equals to less than 3% of the average annual Amazon River discharge. Furthermore, we argue that the river-borne continental water was not confined to the upper mixed layer and show that about 37%, or 76 km3, of its volume was entrained into the plume-underlying layer between the mixed layer and the salinity maximum. This point is additionally supported by analysis of chromophoric dissolved organic matter (CDOM) fluorescence in water samples, demonstrating significant concentrations of terrigenous CDOM to depths up to 140 m. We also observed that there was a significant direct correlation between the volume of freshwater accumulated in the affected layer and background stratification (expressed as buoyancy frequency) in the unaffected layer below it.

Effect of Shoutai Pills on expression of key glycolytic proteins and apoptosis related factors at maternal fetal interface in mouse model of threatened abortion with syndrome of kidney deficiency

This study aims to explore the mechanism of Shoutai Pills in treating threatened abortion. According to the random number table method, ICR female mice were randomized into a normal group, a model group, a dydrogesterone group, and a Shoutai Pills group, with 15 mice in each group. Mice were administrated with normal saline(normal and model groups) or the suspension of Shoutai Pills or dydrogesterone by gavage at 9:00 am every day. At 16:00 every day, mice in the normal group were administrated with an equal volume of distilled water, while those in the model, Shoutai Pills, and dydrogesterone groups were administrated with hydrocortisone solution by gavage for 4 consecutive days. ICR female and male mice were caged in a ratio of 2∶1 during the pre-estrous or estrous period. From the first day of pregnancy, drug administration was continued for 5 consecutive days. On day 6, mice were administrated with mifepristone by gavage to establish the model of kidney deficiency-induced abortion. On day 6 of pregnancy, 10 female ICR mice were randomly selected from each group, and the uterus was collected for observation of the pathological changes of trophoblasts at the maternal-fetal interface by hematoxylin-eosin(HE) staining. The protein levels of key enzymes of glycolysis, hexokinase 2(HK2), enolase 1(ENO1), pyruvate kinase M2(PKM2), and lactate dehydrogenase A(LDHA), were determined by Western blot and immunofluorescence. The expression of apoptosis-related proteins including B cell lymphoma-2(Bcl-2), Bcl-2-associated protein X(Bax), and cysteinyl aspartate-specific proteinase-3(caspase-3) was determined by Western blot and real-time PCR. Terminal-deoxynucleoitidyl transferase-mediated nick-end labeling was employed to examine apoptosis. The embryo loss rate of the remaining five female mice was calculated by trypan blue staining method on day 14 of pregnancy. On day 14 of pregnancy, the embryo loss rate of the normal group was 5.00%, which was lower than that(27.78%) in the model group(P<0.05). Dydrogesterone and Shoutai Pills groups showed reduced embryo loss rates(10.26% and 7.50%, respectively) compared with the model group. On day 6 of pregnancy, compared with the normal group, the model group showed down-regulated expression of HK2, ENO1, PKM2, LDHA, and Bcl-2 and up-regulated expression of Bax and caspase-3(P<0.05). Compared with the model group, dydrogesterone and Shoutai Pills up-regulated the expression of HK2, ENO1, PKM2, LDHA, and Bcl-2 and down-regulated the expression of Bax and caspase-3(P<0.05). Compared with that in the normal group, the apoptosis rate in the model group increased(P<0.05). Compared with the model group, dydrogesterone and Shoutai Pills reduced the apoptosis rate(P<0.05). In conclusion, Shoutai Pills can reduce the embryo loss rate and protect embryos by promoting aerobic glycolysis at the maternal-fetal interface and inhibiting the apoptosis of trophoblasts in mice.

Comprehensive investigation of capacitive deionization cells by response surface methodology

Freshwater resources are limited; thus, different technologies for desalination of brackish and seawater have been developed. Capacitive deionization (CDI) is one of the most promising desalination technologies owing to its low cost, simplicity, nonmoving parts, and low energy consumption. However, its energy consumption significantly increases with desalination of high-salinity water. In this regard, a good understanding of the effects of different process parameters on CDI energy consumption is crucial for further performance improvement. Therefore, the surface response methodology (RSM) was adopted to systematically study the effects of applying voltage, Stern layer capacity, volume and concentration of feed water, and volume of micropores on energy consumption and desalination time. The results showed that the Stern layer capacity and volume of micropores reduced desalination time by approximately 25% without significant changes in energy consumption. With the design of an improved electrode (improving the micropore structure for ion adsorption), the desalination time (Cycle) was reduced and a slight reduction in energy consumption was achieved. It can be claimed that any improvement in the physical (porosity) and electrical properties of the electrodes, results in an important increase in the performance of the CDI system.

Effect of ultrafiltration on whole blood coagulation profile during cardiopulmonary bypass in cardiac surgery: a retrospective analysis.

Ultrafiltration (UF) would enhance coagulation profiles by concentrating coagulation elements during cardiopulmonary bypass (CPB) for cardiac surgery. We retrospectively reviewed electronic medical records of 75 patients who had undergone cardiac surgery with rotational thromboelastometry-based coagulation management in a university hospital and analyzed the UF-induced changes in the maximum clot firmness (MCF) of extrinsically activated test with tissue factor (EXTEM) during CPB in 30 patients. The median volume of filtered-free water was 1,350 ml, and median hematocrit was significantly increased from 22.5% to 25.5%. As the primary measure, UF significantly increased the median MCF-EXTEM from 48.0 mm to 50.5 mm (P = 0.015, effect size r = 0.44). The area under the receiver operating characteristic curve pre-UF MCF-EXTEM for discrimination of any increase of MCF-EXTEM after applying UF was 0.89 (95% CI [0.77, 1.00], P < 0.001), and its cut-off value was 50.5 mm (specificity of 81.8% and sensitivity of 84.2% in Youden's J statistic). In the secondary analyses using the cut-off value, UF significantly increased the median MCF-EXTEM from 40.5 mm to 42.5 mm in 18 patients with pre-UF MCF-EXTEM ≤ 50.5 mm. However, it did not increase MCF-EXTEM in 12 patients with pre-UF MCF-EXTEM > 50.5 mm. There was a significant interaction between pre-UF MCF-EXTEM values and applying UF (P < 0.001 for the subgroup, P = 0.046 for UF, P = 0.003 for interaction). Applying UF improved clot firmness, and the improvement was more pronounced when pre-UF MCF-EXTEM had been reduced during CPB.

Comparative analysis of glymphatic system alterations in multiple sclerosis and neuromyelitis optica spectrum disorder using MRI indices from diffusion tensor imaging.

The glymphatic system is a glial-based perivascular network that promotes brain metabolic waste clearance. Glymphatic system dysfunction has been observed in both multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD), indicating the role of neuroinflammation in the glymphatic system. However, little is known about how the two diseases differently affect the human glymphatic system. The present study aims to evaluate the diffusion MRI-based measures of the glymphatic system by contrasting MS and NMOSD. This prospective study included 63 patients with NMOSD (n = 21) and MS (n = 42) who underwent DTI. The fractional volume of extracellular-free water (FW) and an index of diffusion tensor imaging (DTI) along the perivascular space (DTI-ALPS) were used as indirect indicators of water diffusivity in the interstitial extracellular and perivenous spaces of white matter, respectively. Age and EDSS scores were adjusted. Using Bayesian hypothesis testing, we show that the present data substantially favor the null model of no differences between MS and NMOSD for the diffusion MRI-based measures of the glymphatic system. The inclusion Bayes factor (BF10) of model-averaged probabilities of the group (MS, NMOSD) was 0.280 for FW and 0.236 for the ALPS index. Together, these findings suggest that glymphatic alteration associated with MS and NMOSD might be similar and common as an eventual result, albeit the disease etiologies differ. Previous literature indicates important glymphatic system alteration in MS and NMOSD. We explore the difference between MS and NMOSD using diffusion MRI-based measures of the glymphatic system. We show support for the null hypothesis of no difference between MS and NMOSD. This suggests that glymphatic alteration associated with MS and NMOSD might be similar and common etiology.

On the Spatio‐Temporal Scales of the Subtropical Mode Water Formation in the South Atlantic

AbstractWe examined the changes in the ocean’s upper layer structure involved in the formation of the subtropical mode water in the South Atlantic. Here we present the results from a survey done in the region of formation between 37°W and 32°W and 34°S and 37°S from July–October 2018, using high‐resolution measurements obtained from an underwater glider. From its records, the mode water development was observed for the first time in the South Atlantic as localized chimney‐like patterns in the temperature, salinity, and potential vorticity (PV) measurements with a horizontal scale of (7 ± 2) km, associated with wintertime oceanic convective processes. Over time, these submesoscale structures tend to expand and dominate the region as a large volume of mode water. These vertical structures present highly homogeneous temperature and salinity values. The observed PV was on the order of 5.0 × 10−11 m−1 s−1, which is one order of magnitude smaller than the pre‐existent mode water at the lower layers; negative values were observed, indicating active convection. A 1‐D vertical model was used to predict the depth of the mixed layer conditioned by the surface fluxes and triggered by its changes in winter to late spring. Comparisons of the sea surface temperature measured from satellite collocated with the glider’s measurements showed a very good agreement. From this analysis, we were able to establish the decorrelation scales that characterize mode water formation. Further inspection of the glider data yielded temporal decorrelation scales indicative of convection modified by planetary rotation.

Variation in water utilization by mammal diversity in Khao Phaeng Ma Non-hunting area, Thailand

Access to suitable water sources is important for mammals. This study aimed to compared mammal diversity and water use among water springs, standard artificial ponds, and water pans within the Khao Phaeng Ma Non-Hunting Area in 2020 and 2021. Two camera traps were installed at each water sources for 749 nights with a total of 12 camera traps of 6 water sources. A total of 19,467 photographs were recorded comprising 13,777 photographs of gaur (Bos gaurus, vulnerable and the most important species in the area), and 5690 photographs of other mammals. In the wet season, relative use was highest at standard artificial pond number 2, which is established in the forest plantation area (4 × 4 m spacing, 12–20 m height, and 60%–80 % crown cover) and has a high volume of water, and at water pan number 1, which mimics a natural water spring in the man-made grassland and can supply water to mammals throughout the year. In the dry seasons, relative use was highest at water pan numbers 1 and 2; at the same time, other water sources dried up. During the study period, the number of mammal species was highest at water pan number 1 (10 species, diversity index [H′] = 1.38), and water pan number 2 (11 species, H′ = 1.75). Grazers and browsers, including gaur, sambar deer (Rusa unicolor), northern red muntjac (Muntiacus vaginalis), omnivores (e.g. wild boar, Sus scrofa), and Asian black bear (Ursus thibetanus), used the water pan in the artificial grassland and standard artificial pond in the forest plantation rather than the water spring in the dry evergreen forest. Beside forest types, the use of water springs was associated with water period (months), while the use of standard artificial pond and water pans was associated with water surface area, water depth, altitude, species diversity, and species richness, and number of mammals photographed. The results show that water pans were more suitable for utilization by mammals than are other water sources.

Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designs

Water management plays a key role in ensuring optimum polymer electrolyte fuel cell (PEFC) performance, and flow field design can influence the ability of a cell to balance maintaining hydration, whilst avoiding flooding and cell failure. This work deepens the understanding of water evolution in different PEFC flow channel designs, namely single serpentine (SS), double serpentine (DS) and parallel, using our novel high-speed neutron computed tomography method. We developed our previously-reported method by introducing continuous cell rotation, enabling 18 s per tomogram during 1 h holds at 300, 400 and 500 mA cm−2. The volume of water evolved in the cathode, membrane electrode assembly and anode was quantified, and key mechanisms for water droplet formation in the different flow channel designs were elucidated. The parallel flow field design had the poorest water management, with 47% of the cathode flow channel becoming filled after 1 h at 400 mA cm−2. This significant flooding blocked reactant sites and contributed to unstable cell performance and, ultimately, cell failure at higher current densities. The SS cell displayed the best water management, with only 11% of the cathode channel filled with water after 1 h at 500 mA cm−2, compared with 28% of the DS cathode channel. 3D visualisation and analysis of droplet behaviour elucidated how water ‘slugs’ in the SS were removed in the gas stream, whereas three of the four parallel cathode flow channels became entirely filled with water plugs, blocking gas flow and exacerbating cell flooding. The new insights gained here are expected to extend to novel flow field designs and image-based models, with the use of operando neutron CT demonstrated as a powerful technique for both visualising and quantifying water management in operating PEFCs, as well as deepening the knowledge of droplet behaviour in different flow field types.

Reverse osmosis-based water treatment for green hydrogen production

We analyze the use of excess natural gas (currently flared/vented) to instead treat oilfield-produced water via reverse osmosis (RO) to generate ultrapure electrolysis-grade water (Total Dissolved Solids (TDS): 0.028‐0.5 ppm) for green hydrogen production. We combine an analytical ε-MTU model and CPavg model to predict average permeate concentration, to obtain improved estimates of electrolysis-grade water production from RO systems. The theoretical upper limit of the recovery of a RO system (similar to Carnot efficiency of heat engines) is established. Analysis is conducted for conditions corresponding to Niobrara Shale field (TDS: 29.1 g/L), as well as for brackish water (TDS: 5-15 g/kg) and seawater (TDS: 35–45 g/kg) feeds. Results show that electrolysis-grade water production can be as high as 0.75 m3 per cubic meter of water treated, with 1.38 m3 of natural gas providing the required energy. This translates to hydrogen production of 74.6 kg per cubic meter of produced water treated. Relatively low volumes of gas can treat large water volumes (<4 % of excess gas in Niobrara Shale can treat the entire quantity of produced water). These numbers highlight the benefits of our approach of utilizing two waste streams to create a high-value commodity, critical for decarbonization.

Energy trade tempers Nile water conflict

The demand for energy, water and food in Africa continues to increase, resulting in growing pressure on contentious multisector resource systems like the River Nile. The ongoing dispute over Nile resources could become a zero-sum game if addressed from a water-centric viewpoint. Understanding how energy system management impacts water infrastructure introduces new opportunities to solve water conflicts. Although benefit-sharing of water resources in the Nile Basin has been promoted to counteract water volume disputes, it has not yielded actionable solutions to the toughest negotiations over the past two decades. Here we develop a detailed and integrated energy–river basin system simulator of 13 East African countries, including the Nile Basin, and show how new electricity trade agreements between Ethiopia, Sudan and Egypt could help resolve the ongoing water dispute over the Grand Ethiopian Renaissance Dam. The results show that increasing energy trade can reduce Egyptian water deficits, reduce regional greenhouse gas emissions, increase hydropower generation in all three countries, reduce energy curtailment in Sudan and increase Ethiopia’s financial returns from electricity. This study underscores how spatial quantification of river–energy system interdependencies can help decision-makers find actionable multisector benefit-sharing solutions.