Water Circulation Research Articles

Cleaner and cost-efficient hydrometallurgical process for extraction of vanadium from Bayer vanadium sludge based on BaSO4, NaOH, ammonium, and water circulation

Bayer vanadium sludge(BVS) is a hazardous waste due to its high contents of V, P, As, and F. Full or partial utilization of this sludge could not only minimize the potential environmental risk but also promote resource recycling. In this work, a cleaner and cost-efficient process was proposed to selectively extract vanadium from BVS by employing BaSO4 as precipitant. Under the optimal conditions, a maximum vanadium precipitation efficiency of 97.86% is achieved, whereas only 1.15% arsenate and 0.12% fluoride are co-precipitated. Afterwards, the generation of 2Na3AsO4·NaF·19 H2O and NaSO4·NaF has enhanced the simultaneous removal of As and F during evaporation crystallization, and achieving the recycling of NaOH. A new strategy was adopted to in-situ convert Ba3(VO4)2 into Ba(VO3)2·H2O which can be directly leached in (NH4)2SO4 solution. Furthermore, 99.78% vanadium is precipitated as (NH4)2V6O16 from the leachate and the V2O5 product with a purity of 99.85% is prepared after calcination. The leaching residues and the spent liquor containing large amounts of NH4+ after (NH4)2V6O16 precipitation can be circulated to the next batch of vanadium precipitation and leaching, respectively. Herein, the process realizes the internal circulation of BaSO4, NaOH, ammonium, and water, saving production costs and avoiding environmental pollution.

Increasing actual evapotranspiration on the Loess Plateau of China: An insight from anthropologic activities and climate change

Actual evapotranspiration (ETa) is an important element of water circulation, and susceptible to environmental change. Precise estimation of ETa and identifying its key influence factors are of great importance. Loess Plateau has been largely affected by human activities and climate change, and the dynamics of ETa and its key influencing factors remain unknown in this region. The spatio-temporal variations of ETa over Loess Plateau from 2000 to 2020 were depicted on the basis of the ETWatch model. Then the individual contributions of climatic factors and human activities to ETa variation were quantified by applying generalized additive model. Results indicated that the annual average ETa during the period of 2000–2020 displayed a fluctuating increasing pattern from 386.67 mm in 2000 to 544.73 mm in 2020, with a growth rate of 6.25 mm⋅yr−1. Spatially, the ETa displays a downward pattern from southeast to northwest, which is highly similar to vegetation coverage with the coefficients of 0.766–0.832. The ETa of forest, grassland, cropland, shrub, barren land and impervious land exhibited positive or negative significantly correlations with their corresponding land cover area at the 0.05 or 0.01 level. Sunshine duration, temperature and precipitation are the top three factors showing high correlations with ETa. The results of contribution analysis suggested that the variations in ETa were largely controlled by LUCC in the Loess Plateau, where the LUCC accounted for 52.89% of the total ETa. The impacts of LUCC on ETa were greater than that of climate change on ETa, although climate change was dominant in a few years. These results could contribute to optimizing water resource management and developing various water-saving tactics in the Loess Plateau.

Feasibility analysis of storing solar energy in heterogeneous deep aquifer by hot water circulation: Insights from coupled hydro-thermo modeling

Feasibility analysis of storing solar energy in heterogeneous deep aquifer by hot water circulation: Insights from coupled hydro-thermo modeling

Water circulation in Ryugu asteroid affected the distribution of nucleosynthetic isotope anomalies in returned sample

Studies of material returned from Cb asteroid Ryugu have revealed considerable mineralogical and chemical heterogeneity, stemming primarily from brecciation and aqueous alteration. Isotopic anomalies could have also been affected by delivery of exogenous clasts and aqueous mobilization of soluble elements. Here, we show that isotopic anomalies for mildly soluble Cr are highly variable in Ryugu and CI chondrites, whereas those of Ti are relatively uniform. This variation in Cr isotope ratios is most likely due to physicochemical fractionation between 54 Cr-rich presolar nanoparticles and Cr-bearing secondary minerals at the millimeter-scale in the bulk samples, likely due to extensive aqueous alteration in their parent bodies that occurred 5.2 − 1.4 + 1.8 Ma after Solar System birth. In contrast, Ti isotopes were marginally affected by this process. Our results show that isotopic heterogeneities in asteroids are not all nebular or accretionary in nature but can also reflect element redistribution by water.

The Principle of Construction of the Boiler Control System With Efficient Use of the Solid Fuel

The system for controlling the economic opera- tion of a solid fuel boiler is a device that controls and moni- tors the processes that occur during fuel combustion and water circulation in a solid fuel boiler. The system describes the combination of two main components: software and hardware. Based on these components, this article presents the method of building a system of economic operation of a solid fuel boiler, describes the development environment with its functions and capabilities, provides a detailed de- scription for the user with explanations of key points in the operation of the system. This system is aimed at improving the quality of room heating and optimizing this process in order to regulate the desired temperature for the user with minimal error. All software tools interact with each other according to clearly defined protocols, so there are no sys- tem failures.

Ballast Water Management in Ports: Monitoring, Early Warning and Response Measures to Prevent Biodiversity Loss and Risks to Human Health

Ballast water is recognised as successfully transporting non-native (potentially) invasive alien species and other harmful organisms (human pathogens and toxic phytoplankton) from one region to another. Global warming enables the successful adaptation of non-native species in new areas. The early detection of harmful species increases the likelihood that the response will be effective and cause less damage to biodiversity, ecosystems, economies and human health. Scientific evidence strongly points to the importance of prevention. In this context, this refers to continuous port monitoring, carried out with the aim of detecting harmful species soon after their introduction. The objectives of rapid detection are (a) early warning and prevention of further spread of harmful species through ballast water or natural circulation, and (b) a timely response through eradication or other appropriate strategies to reduce the number or spatial extent of introduced species. This paper provides guidance for the development of ballast water management in ports based on a literature review. Available and new methods for identifying marine species and best practises in port monitoring for the early detection of harmful species, as well as early warning and response measures following the introduction of species in ports, are presented and discussed.

Influence of temperature and process water circulation on hydrothermal carbonization of food waste for sustainable fuel production

To address the challenge posed by energy shortages, this study focuses on the conversion of food waste (FW) into valuable resources. Employing hydrothermal carbonization (HTC) technology, the research successfully converted FW into an efficient solid fuel. Furthermore, it conducted an extensive investigation into how hydrothermal temperature (ranging from 180 to 260 °C) and the recycling of process water (repeated four times) influence the physical and chemical properties, as well as the combustion characteristics, of hydrochar fuel. The study's findings reveal that with an increase in hydrothermal temperature, the hydrochar yield decreases. However, this reduction can be mitigated by increasing the number of process water cycles. Notably, when the hydrothermal temperature surpasses 220 °C, the O/C and H/C ratios of hydrochar fall within the range characteristic of lignite, resulting in a higher heating value (HHV). Moreover, as the hydrothermal temperature and the number of process water cycles rise, the –C−(C, H)/CC bonds in aromatic vibrations become stronger, indicating the occurrence of aromaticization and polymerization reactions during this process. Hydrochar exhibits a more stable covalent cross-linked structure, which broadens its combustion range and reduces its reactivity. The combustion rate of hydrochar is significantly lower than that of FW, implying that it is more readily combustible. In summary, the utilization of HTC on FW and the recycling of process water can effectively transform it into a more stable solid fuel.

HIGHLY EFFECTIVE DIRECT CONTACT HUMIDIFIER FOR THERMAL DESALINATION SYSTEM

The aim of the work is to increase the efficiency of thermal desalination systems with a humidification-dehumidification air cycle due to the reduction of electricity consumption. The most common designs of heat exchangers for air humidification have significant aerodynamic and hydraulic drops. To eliminate this disadvantage, it is proposed to use the internal volume of the vertical tube as an active heat and mass transfer zone during moisture evaporation from salt water to air. The operation of such desalination system has been mathematically modeled and its energy characteristics were determined. A special feature of the mathematical model is the consideration of heat and mass transfer equations for the humidifier and dehumidifier. The effective air velocity in the tube is 3 m/s. Effective operation of thermal unit with a film humidifier is possible then air mass flow is equal to the salt water flow. In this case, the geometric dimensions of the tube must be within the following limits: diameter 20...30 mm, height 2...2.5 m. The conducted mathematical modeling and obtained results give reasons to assert, that for the same rate of evaporation, the film heat exchanger has the lowest aerodynamic and hydrodynamic drops compared to other types of humidifiers. The use of such direct contact device will lead to a decrease in the electricity consumption necessary for salt water and air circulation in the humidification-dehumidification thermal installation.

Hydrogeochemical Characteristics of Geothermal Water in Ancient Deeply Buried Hills in the Northern Jizhong Depression, Bohai Bay Basin, China

The Jizhong Depression boasts rich geothermal resources with a lengthy history of geothermal exploitation. Buried hill geothermal reservoirs, which serve as primary thermal sources for hydrothermal resource exploitation, are prevalent in this region and have advantages such as extensive development potential, significant geothermal reservoir capacity, superior water quality, and straightforward recharge. This study investigates the formation and evolution of deep geothermal water in the Jizhong Depression by analyzing the hydrochemical and isotopic data of geothermal water samples collected from buried hill geothermal reservoirs in the northern part of the depression. The findings reveal that the subsurface hot water samples from the carbonate geothermal reservoirs in this region were predominantly weakly alkaline water with a pH ranging between 6.61 and 8.87. The hot water samples collected at the wellhead exhibited temperatures varying from 33.9 °C to 123.4 °C and total dissolved solids (TDS) lying between 473.9 mg/L and 3452 mg/L. Based on the δ2H-δ18O stable isotope analysis, the geothermal fluids in the Jizhong Depression are predominantly sourced from atmospheric precipitation and exist in a somewhat isolated hydrogeological environment, exhibiting pronounced water–rock interactions and deep water circulation (with depths ranging from 1324 m to 3455 m). Through a comparison of various methods, it is deduced that the most appropriate geothermometer for deep karst geothermal reservoirs in the Jizhong Depression is a chalcedony geothermometer, and when using it, the deep reservoir temperature was estimated at 63–137.6 °C. The precipitation in the adjacent mountainous areas enables the groundwater to infiltrate and descend deep into the earth along piedmont faults. Subsequently, lateral runoff over extended periods replenishes the groundwater into the depression. This process allows for the groundwater to fully absorb heat from deep heat sources, resulting in the formation of the deep geothermal reservoirs in the northern Jizhong Depression. The insights obtained from this study offer a theoretical and scientific foundation for the exploitation and utilization of regional geothermal resources and the transformation of the energy structure in China.

Development of design calculations for radiant ceiling panels incorporating phase change materials (PCMs)

Thermally active building systems (TABS) show significant benefits such as providing peak load shifting, peak load reductions, and energy savings. Phase change material (PCM) applications with water circulation have benefits similar to TABS, but PCMs can store more heat per unit volume than concrete due to the latent heat exchange. Radiant panels with PCM can be applied in building retrofit, which gives this application a significant advantage compared to TABS. A design methodology for determining heat flux does not exist though for dimensioning a radiant ceiling system that incorporates PCM. Design methods according to standards for TABS – ISO 11855-2 and for radiant panels – ISO 18566-3 were investigated. Five radiant ceiling panels incorporating PCM were selected from Denmark, Canada, Germany, the Czech Republic and Latvia. The resulting heat flux between the panel and conditioned space, i.e. the room, following methods represented in the standards, were compared with the measured or simulated values reported in the literature. The comparison showed that the calculation for TABS (ISO 11855-2) led to similar results to the measured or simulated values.

Influence Analysis of Impeller-Guide Vane Matching on Energy and Pressure Pulsation in a Tubular Pump Device

Tubular pump devices offer advantages such as low hydraulic losses, a simple structure, and easy maintenance. They find extensive application in areas such as irrigation, flood control, and water diversion. The performance and security of the pump are directly impacted by the contact between the impeller and guide vane. The matching relationship between the number of impeller blades and guide vanes significantly influences this interaction in tubular pump devices. To explore this impact, a Very-Large-Eddy Simulation turbulence model was employed to simulate the 3D flow fields of six different number matching relationships in a shaft tubular pump device. The analysis focused on the energy performance of the different schemes, the flow distribution of the guide vanes, and the velocity circulation at the guide vanes’ outlet. Entropy theory and energy gradient theory were employed to understand how the number matching relationship influences energy performance. Additionally, pressure pulsations were analyzed at the impeller and guide vanes for different matching configurations. The results indicate that although increasing the number of impeller blades can lead to higher water circulation, increased energy, and potentially unstable water flow, an increase in impeller blades number results in improved flow distribution in each guide vane groove, leading to an overall enhancement in the efficiency of the pump device. Similarly, increasing the number of guide vanes may increase the non-uniformity of the guide vane flow rate, but it also enhances the ability of the guide vanes to regulate water circulation and recover energy, thereby benefiting the overall efficiency.

Intraannual Variability of the Cyclonic Circulation of Water in the Middle Caspian Sea

Intraannual Variability of the Cyclonic Circulation of Water in the Middle Caspian Sea

Aeration strength analysis of overflow weir in siphon well based on numerical simulation of water–air two‐phase flow

AbstractThe phenomenon of water aeration is serious after the overflow weir in the siphon well at the cooling water circulation system of coastal power plants. At present, designing special hydraulic structures is an effective way to reduce the intensity of aeration. In this paper, three engineering structure schemes were designed, and the three‐dimensional Realizable k–ε turbulence model was used. The volume of fluid method was introduced to capture the free water surface, and the unstructured grid was used to construct the two‐phase turbulent flow field. The aeration concentration and pressure distribution, obtained by numerical simulation, were basically consistent with the physical model test results. The results showed that the flow field at the orifice plates of cases 1 and 2 changed drastically, and the turbulent kinetic energy downstream of the orifice plate decreased with the increase of the number of holes. As for case 3, it showed that the high‐speed water flow fell into the water cushion pool, tumbling and sucking up a lot of air, and the turbulent kinetic energy and Reynolds stress were significantly greater than the other two cases. The hydraulic structure changed the cavitation characteristics of the downflow water, and the sequence of aeration concentration of the horizontal section was case 3 > case 1 > case 2. The aeration concentration was only 9.18%–17.86% in case 2. The aeration concentration at stable time is expressed as a function of the relative water depth y/y90 and the turbulent diffusion coefficient D. The distribution formula of aeration concentration was established, and its validity was verified by literatures. The results of this study will provide a certain reference for in‐depth analysis of water–air mixing motion characteristics, and simultaneously, it will have a guiding significance for the design of siphon well defoaming engineering.

Water Circulation System of a Sunken Plaza Based on the Concept of a Sponge City Utilizing Groundwater

Water Circulation System of a Sunken Plaza Based on the Concept of a Sponge City Utilizing Groundwater

Randomly Distributed Crab Burrows Enhance Groundwater Flow and Salt Transport in Creek‐Marsh Systems

AbstractMacropores created by crab burrowing are commonly found in vegetated coastal wetlands. However, their impact on surface water‐groundwater interactions and salt transport is insufficiently understood. In this study, we used numerical models to quantify the impact of crab burrows with random spatial distribution, morphology, and openings on groundwater flow and salt transport in creek‐marsh systems. Results showed that these burrows can lead to a more complex network of preferential flow paths and burrow flushing capabilities than those with a single pipeline. The velocity magnitude varied over seven orders in the burrowed mud layer. Local increases in the hydraulic gradient occurred in the burrows, leading to faster water circulation and salt transport as well as turnover of soil aeration. The salinity front in the burrowed marsh reached two‐m deeper than in the unburrowed marsh. Burrow flushing depth and intensity is significantly enhanced in burrows with multiple openings. This study emphasized the complexity of tortuous burrows regulating groundwater flow and solute transport through modeling realistic crab burrows. This work supports fiddler crabs as ubiquitous “ecoengineers” who can produce more significant impact on local hydrological cycle and ecosystem‐scale geochemical processes than previously indicated.

The Present-Day Structure of the Temperature and Current Fields in Lake Sevan

Long-term features of the vertical and horizontal structure of water temperature field in Lake Sevan are discussed. It is shown that the climate warming has led to an increase in epilimnion temperature in Bol’shoi Sevan in July by 2.0‒3.0°C. The increase in water temperature in hypolimnion was not greater than 1.1°C. In autumn (October), the epilimnion became 1.2°C warmer, while hypolimnion temperature practically has not changed on the average over years. Temperature fields were used to calculate the density currents in summer and autumn periods. A dominating cyclonic water circulation was revealed all over the lake, confirmed by chlorophyll distribution by satellite image data. In the case of large horizontal gradients of water density, the flow velocity can reach 50 cm/s. Autonomous buoy stations revealed a wide range of water temperature variations due to internal waves of different nature. The reversible vertical mixing of water mass by internal waves plays an important role in the distribution of nutrients and plankton within the water mass. The water level rise by ~3 m, unlike it drop by 1981 by 18.48, has not caused any significant changes in lake hydrological regime.

Effects of different conditions on the artificial incubation effect and physiological indexes of redclaw crayfish eggs

We explored the effects of different conditions on the artificial incubation of redclaw crayfish eggs in an effort to improve this process. Samples at the egg and juvenile stages were selected. The samples at different stages were separated from the pleopods, then they were placed in incubator boxes and sterilized with different disinfectant solutions. The density was 300,400 and 500 eggs/incubator box, the vibration frequency was 11,16 and 26 vibrations/min, and the water circulation cycle was 2.1, 4.8 and 7.1 cycles/h. The results showed the eggs disinfected with 3000 ppm formaldehyde for 15 min had stronger antioxidant capacity. The hatching and survival rates of five pairs of appendage stage group were significantly lower than those of other groups. In the egg stage, acid phosphatase (ACP) level of compound eye pigmentation stage group was significantly higher than those of other groups. In the juvenile stage, malondialdehyde (MDA) content of five pairs of appendage stage group was significantly higher than those of other groups. The survival rate of 500 eggs/box group was significantly higher than that of other groups. In the egg stage, alkaline phosphatase (AKP) level of 400 eggs/box group was significantly higher than that of other groups. The survival rate of 11 vibrations/min group was significantly higher than that of other groups. In the egg stage, ACP and AKP levels of 11 vibrations/min group were significantly higher than those of 26 vibrations/min group. In the juvenile stage, superoxide dismutase (SOD), ACP and AKP levels of 11 vibrations/min group was significantly higher than those of 26 vibrations/min group. In the juvenile stage, AKP level of 4.8 cycles/h group was significantly lower than that of other groups. In conclusion, egg development at the stage after seven pairs of appendages, with a density of 400 eggs/box, vibration frequencies set at 11 vibrations/min achieved high hatching rates (93.58 %) and survival rates (75.67 %). Moreover, bronopol or hydrogen peroxide might have a better choice to replace formaldehyde if further exploration was conducted to reduce stimulation of the in vitro-grown egg. These conditions could be used on a large scale to optimize the production of redclaw crayfish.

A study on the geothermal circulation system of granite: An example from the Lancang area, Yunnan

This study assesses the geothermal water circulation process of a granite geothermal system in the Lancang area, Yunnan. Cycling processes are studied using water chemistry and isotope analysis techniques. The results show that the water chemistry type of the hot springs in Lancang is Na-HCO3, with TDS values ranging from 246 to 724 mg/l. The granite pluton, as the main heat source, has a high radiogenic heat generation rate (4.17 μW/m3 on average). δD and δ18O in Lancang are close to the global atmospheric and local precipitation lines, indicating that geothermal water originates from atmospheric precipitation. Moreover, the mountainous area from 1295.3 to 1624.5 m above sea level is the main precipitation recharge area. In addition, the main ions of geothermal water mainly come from the dissolution, weathering, and cation exchange of silicate minerals in granite, and Ca2+ and Mg2+ in the water are exchanged with Na+ and K+ in the reservoir, significantly increasing the Na+ and K+ concentrations in the water. The reservoir temperatures are 126.60 °C to 151.32 °C based on the SiO2 geothermometer, and the depths range from 2283.05 to 4024.59 m. The NW- and NE-oriented fault system in Lancang serves as a channel for geothermal water to exit the ground and form hot springs; this water is also mixed with cold water during upwelling, and the mixing ratios are 63 %-84 %. Finally, the model of geothermal water circulation in the Lancang is established.

Mineral Scaling Impact on Petrophysical Properties of Reservoir Rock in a Geothermal Field Located in Northwestern Iran

Summary As the usage of geothermal energy as a zero-emission power resource continues to grow in significance, comprehending the interplay between physical and chemical processes within geothermal reservoirs becomes crucial. In this study, a computationally efficient fluid flow and heat transfer model, combined with a fluid chemistry model, is used to simulate fluid circulation and mineral precipitation in reservoir rock, resulting in changes in rock porosity and permeability. A 2D hybrid approach is employed to solve transient mass and momentum conservation equations, coupled with an analytical solution of the energy equation proposed in the literature for geological formations. A marching algorithm is utilized to calculate velocity and temperature fields in the axial direction within the production zone. Mineral scaling is addressed using the outputs of the hybrid model to perform saturation index (SI) and solution/dissolution computations for qualitative and quantitative mineral precipitation modeling. Multiple criteria are considered to assess the likelihood and intensity of fouling issues. The analysis results are used in an empirical model to estimate rock secondary porosity and permeability changes over a 5-year period of heat extraction. The developed simulator is applied to model a site in the Sabalan geothermal field in Iran, and its initial verification is conducted using data from the same site in the literature. The findings in the study for a sensitivity on fluid circulation rate reveal that increasing water circulation flow rate increases precipitation rate and pumping power required. Furthermore, even minor instances of pore blockage can result in notable reductions in permeability. Consequently, ensuring precise control over pressure and temperature during the production phase becomes progressively crucial for both reservoir integrity and production assurance. The proposed framework provides a promising approach for accurate and efficient simulation of geothermal reservoirs to optimize power generation and minimize environmental impact.

Effect of Hydraulic Structure on Mitigating Extreme Hydrological Conditions of a Small River in the Temperate Zone (Główna River, Central Europe)

Water resources are of elementary economic and environmental importance, and the observed global transformations as well as regional environmental conditions necessitate activities aimed at providing an optimal amount of water at different levels. One such solution is hydrotechnical infrastructure that permits the precise control of the amount of water in the catchment. This paper presents results concerning changes in the water flow in the Główna River in Poland before (1955–1983) and after (1984–2021) the construction of the Kowalski Reservoir. In the former period, there were no changes in water flow, and the obtained results were not statistically significant (p 0.05). In the period after the construction of the reservoir, a decreasing trend in monthly flow was observed in December, April, July, September, and October. Moreover, a decrease in 1, 3, 7, and 90 day maximum flow was observed. For maximum 30 day flow, the changes were below the threshold of the adopted significance level. Moreover, minimum flow in the period after the construction of the reservoir showed no significant decreasing trend. In hydrological terms, the reservoir served its purpose by contributing to the stabilisation of the water flow. This information is important from the point of view of an increase in retention and corresponds with a broader programme conducted in the territory of Poland. In the context of the construction of further reservoirs, it is important to investigate the current range of changes in water circulation for objects of the type already functioning in the environment, constituting an actual point of reference.