Water Discharge Research Articles

Experimental and numerical study on transcritical CO2 air source heat pump water heater

As environmental problems become more and more serious, CO2 is widely used as a natural work material in heat pump water heaters. In order to better improve the performance of CO2 air-source heat pump water heater, a trans-critical CO2 quasi-two-stage compression heat pump system with ejector (TCIEJ) is proposed. And a transcritical CO2 air-source heat pump water heater experimental bench was built. The effects of parameters such as cooling water flow rate, high pressure and compressor frequency on the performance of the heat pump were tested. A simulation model of TCIEJ was also developed to simulate the system performance. The results show that when the cooling water flow rate is increased from 70 kg/h to 122.5 kg/h the COP is improved by 30 %, while the cooling water discharge temperature is reduced by 15.4 %. System performance can be enhanced by increasing the cooling water flow rate within the temperature range required to meet hot water demand. When the high-pressure pressure of the TCIEJ system was increased from 8.0 MPa to 10.4 MPa, the cooling water discharge temperature increased by 17.66 °C on average. Even in the ambient temperature of 0 °C high-pressure pressure of 10.4 MPa, the compressor discharge temperature is only 85.77 °C. It shows that the combination of make-up air technology and ejectors effectively reduces the compressor discharge temperature, which is conducive to improving the compressor’s service life.

Double (W1/O/W2) emulsions prepared with natural vegetable oils and varied inner glucose concentration: Microstructure, rheology and stability

The objective was to study the microstructure, rheology and stability of double (W1/O/W2) emulsions prepared with Tween 80 as hydrophilic emulsifier and coconut, palm or sunflower oil. The effects of glucose concentration in inner aqueous phase and crystallization of lipid phase were analyzed. Aggregation of oil globules by partial coalescence was observed in emulsions prepared with coconut or palm oil because of the crystallization of the lipid phase. The increase of glucose concentration increased the amount of inner water by osmotic swelling and produced a higher partial coalescence degree due to a higher collision frequency between oil globules. Consequently, higher elastic and viscous modules were observed at higher glucose concentration. Fat crystals in lipid phase allowed a partial retention of inner water in the absence of glucose, but they also favored the release of inner water due to partial coalescence. Creaming stability was enhanced by the presence of glucose, because of the formation of a three-dimensional network of aggregated oil globules in emulsions with coconut or palm oil, and a higher packing and global density of oil globules in systems with sunflower oil. The obtained results contribute to the understanding of partial coalescence in W1/O/W2 emulsions, including its effects on inner water release and creaming stability. This work could be relevant for the design and stabilization of vegetable, lipid-reduced food emulsions prepared with natural oils.

Exploring aegle marmelos (bael fruit): understanding its health benefits and potential for therapy

The kidneys play a crucial role in maintaining the body's fluid balance through precise regulation of sodium, chloride, and water levels. They expel sodium and chloride, prompting water release and reducing fluid volume. Conversely, retaining these elements leads to water retention and increased fluid volume. This intricate mechanism ensures internal stability. Kidneys filter these substances into tubules, with most being reabsorbed into the blood and exiting as urine. Complex processes in various tubule segments complicate sodium and chloride reabsorption. Diuretics are valuable in treating edema, congestive heart failure, and hypertension. Bael (A. marmelos), a significant herb in Ayurveda, contains compounds like flavonoids and alkaloids. It's used for diarrhea, diabetes, inflammation, and hyperlipidemia. An alcoholic extract from the mature fruit of Aegle marmelos exhibits diuretic activity, potentially assisting with common kidney ailments. Bael's therapeutic potential arises from its diverse compounds and established use in traditional medicine.

Aeromagnetic data reveals buried Quaternary drainage patterns in the Gulf of St Lawrence (Canada)

Short-wavelength, low-amplitude magnetic anomalies form dendritic patterns on the shallow water (<100 m depth) Magdalen Plateau in the Gulf of St Lawrence, Canada. High-resolution seismic data indicate that these magnetic anomalies are associated with 0.6–2 km wide incised Quaternary valleys with relatively flat bottoms lying 30–70 m below the seafloor. The magnetic signature of the valleys is due to high magnetic susceptibility volcanic detritus derived from the erosion of the volcanic rocks that overlie most of the salt bodies in this area. This study shows that magnetic data may be a useful tool for mapping surficial sediments. These magnetic data provide the first offshore evidence for the direction of major water discharge. It remains unclear whether the valleys were formed by river incision during one or several regional lowstand(s) or from one or several sub-glacial discharge episode(s) across the Magdalen Plateau. The valley evidence should be incorporated into any future palaeogeographical reconstructions.

Analysis of Local Scour around Double Piers in Tandem Arrangement in an S-Shaped Channel under Ice-Jammed Flow Conditions

The stability of bridge foundations is affected by local scour, and the formation of ice jams exacerbates local scour around bridge piers. These processes, particularly the evolution of ice jams and local scour around piers, are more complex in curved sections than in straight sections. This study, based on experiments in an S-shaped channel, investigates how various factors—the flow Froude number, ice–water discharge rate, median particle diameter, pier spacing, and pier diameter—affect the maximum local scour depth around double piers in tandem and the distribution of ice jam thickness. The results indicate that under ice-jammed flow conditions, the maximum local scour depth around double piers in tandem is positively correlated with the ice–water discharge rate, pier spacing, and pier diameter and negatively correlated with median particle diameter. The maximum local scour depth is positively correlated with the flow Froude number when it ranges from 0.1 to 0.114, peaking at 0.114. Above this value, the correlation becomes negative. In curved channels, the arrangement of double piers in tandem substantially influences ice jam thickness distribution, with increases in pier diameter and spacing directly correlating with greater ice jam thickness at each cross-section. Furthermore, ice jam thickness is responsive to flow conditions, escalating with higher ice–water discharge rates and decreasing flow Froude numbers.

Sediment runoff formation in a small periglacial catchment on the King George (Vaterloo) island, Antarctica

Global climate change has most significantly affected the Polar Regions. The increase in air temperature has stimulated the melting of glaciers in the Arctic and Antarctic, which has contributed to changes in the formation of water and sediment runoff. However, there are very few quantitative estimates of the sediment redistribution in the periglacial catchments of the Polar Regions. Specific features of water and sediment runoff were studied within the catchment area of the Korabelnyj Stream located on the Fildes Peninsula in Antarctica near the Bellingshausen Ice Dome. The main aim of the study was to investigate the conditions for the formation of water and sediment runoff and to identify the proportional contribution of washout and erosion material coming from the periglacial and maritime parts of the catchment area to the sediment runoff of the stream. A set of methods and approaches, including: a) estimates of the sediment flow connectivity index; b) fingerprinting technique; c) hydrometeorological observations; d) large-scale geomorphological survey and others, was ap[1]plied to identify the conditions for the formation of surface runoff and washout, the mechanisms of sediment redistribution in various parts of the fluvial network and to quantify the proportional contribution of two main sediment sources to the sediment runoff of the stream. A fraction with a particle size of ≤63 μm was used for geochemical and spectrometric analyzes of soils and sediments. In total, the content of 34 elements was analyzed, i.e. 6 radioisotopes and 28 stable elements. It has been established that despite the significant differences in the relief of the near-glacial and maritime parts of the catchment area, the indices of sediment connectivity are quite close and amount to –1,79 and –1,35, respectively. A significant part of the material transported by temporary streams from the slopes of the catchment area is redeposited in relief depressions partially occupied by water bodies. The main volume of sediments, which is at least 60–66% of the total sediment runoff in the outlet section of the Korabelnyj Stream, comes from the periglacial part of the catchment area. This is due to the increased water discharge relative to the non-glacial part of the catchment area, which results from the melting of snow and ice accumulated on the ice dome, the high erosion of moraine deposits unprotected by vegetation, and the presence of an ice core in moraines, which prevents water filtration.

Conceptual framework to incorporate drainage solutions in the urban open space system

Cities are increasingly dealing with challenges regarding the negative impact of rapid and mismanaged urbanization. Therefore, city planning must cope with the natural environment limitations, seeking a balance between the human activities and the well-functioning of the hydrologic cycle. This work aims to present a conceptual framework able to properly integrate the stormwater dynamics into the open spaces system in a functional way, establishing a Hydrological Interest Area, HIA, to structure urban expansion integrated into and respecting watershed natural processes. The initial step is to define a HIA, primarily consisting of open spaces that can be used for supporting urban drainage functions and to order land use in the urban expansion process. This delimitation offers the background for interpreting the watershed in three functional arches, especially covering the upstream, mid-reach and downstream areas of the basin, guiding the design of a set of flood mitigation interventions focusing on the use of Blue-Green Infrastructure. To illustrate and validate the proposed methodological framework, the design is evaluated by a flood modeling tool, using a hydrological-hydrodynamic cell-model. A case study was driven in the Bambu Watershed, a rapidly developing area in the municipality of Maricá, Rio de Janeiro, Brazil. The proposed intervention includes an urban expansion scenario for a low impact development on flood behavior alongside with four parks: an upstream park with reservoirs, two multifunctional floodable urban parks, and a park dedicated to lagoon restoration. This plan complements riverbed modifications designed to enhance water discharge. The simulation showed significant reduction of water depths with a consequent decrease in exposure of buildings and roads, especially in the most critical region of the watershed. This framework highlights the importance of a multifunctional approach in land use and serves as a robust foundation for controlling urban expansion and proposing projects.

Simulation of the pulsed streamer discharge in water considering the effect of hydrostatic pressure

Streamer discharge is a very complex multi-scale and multi-physics coupling process, and there is no accurate model that can describe its development. In this paper, a two-dimensional axisymmetric fluid model is established in COMSOL to simulate and study the effects of the applied voltage amplitude, the discharge gap distance, the rising edge of pulse voltage, and hydrostatic pressure on the development of the positive streamer discharge at a needle-plate electrode in water under a nanosecond pulse voltage. The results show that increasing the voltage amplitude, decreasing the pulse rise time, and narrowing the discharge gap all increase the electric field strength of the streamer, thereby affecting the electron density of the plasma channel, among which changing the discharge gap has the greatest effect on the electron density. And under the gap of 3 mm, the peak electron density can reach 3.76 × 1023 m−3; if the discharge gap is narrowed to 1 mm, the peak electron density is reduced to 1.20 × 1023 m−3. In addition, hydrostatic pressure and water molecule spacing are closely linked. Increasing the hydrostatic pressure decreases the electric field strength and the peak electron density in the plasma channel, and its effect on the peak electron density saturates with increasing hydrostatic pressure.

Numerical Simulation Analysis of Discharge in Water Under Different Pressures

Numerical Simulation Analysis of Discharge in Water Under Different Pressures

Intelligent hybrid hydrogel with nanoarchitectonics for water harvesting from acidic fog

With the development of society, the demand for water resources has risen has increased sharply, and water shortage is becoming a huge challenge to mankind. Therefore, it is extremely urgent to develop a convenient, low-cost, and environmentally friendly fog harvesting material. In this work, inspired by lotus stem with efficient water transport characteristics, the intelligent hybrid hydrogel (IHH) synergistically combines the characteristics of the pH-sensitive PDMAEMA polymer chain and thermo-switchable PNIPAM polymer chain, which simultaneously realizes superior efficient acidic fog uptake (∼6.5 g/g), high-density acidic fog storage, ultra-fast clean water releasing in the efficiency of ∼90 % for 12 min at 60 °C and high cycling stability (∼25 cycles). It is mainly attributed that the amine groups of the PDMAEMA chains are protonated under acidic state, and further the hydration is enhanced, and thus resulting the hydrogel to absorb the acid fog and swell. The PNIPAM polymer can achieve a rapidly reversible phase transition from a hydrophilic state to a hydrophobic one when the temperature beyond LCST, achieving the water releasing quickly. This IHH achieves preliminary water purification, which converts the harvested acidic fog into clean water as the freshwater generator. The IHH offers an insight into the design of novel materials that serve as the freshwater generator in complex environments of practical applications such as fog harvesting devices or systems.

Willingness to eat seafood among Taiwanese after the 2023 Fukushima radioactive water release: An extended Theory of Planned Behavior approach

The release of radioactive water from Fukushima in 2023 emerged as a significant nuclear issue, particularly affecting Taiwanese perceptions. This study aimed to investigate the willingness of Taiwanese people to consume seafood following the 2023 Fukushima2 incident, using an extended Theory of Planned Behavior (TPB) model. A total of 204 Taiwanese respondents completed an online questionnaire comprising 28 TPB indicators. The results from Partial Least Square Structural Equation Modeling (PLS-SEM) revealed that subjective norms had the strongest positive influence on the intention to eat seafood, followed by personal attitudes and financial considerations. Interestingly, perceived behavioral control was found to negatively impact the intention to consume seafood. This research is among the first to explore seafood consumption intentions in the wake of the Fukushima water release and provides a robust theoretical foundation for stakeholders aiming to promote seafood consumption, particularly among Taiwanese consumers.

Effect of clayey sediment compression on fluoride enrichment in the Quaternary groundwater system of Cangzhou Plain, China

The effect of clay layer compression on the enrichment of groundwater fluoride remains unknown. Quaternary groundwater with high fluoride levels at the Cangzhou Plain, which has a long history of land subsidence caused by clay layer compression, poses a potential health risk. The spatial distribution and enrichment mechanisms of groundwater fluoride are identified by sample collection, hydrochemical analysis, and geochemical inverse modeling. The results revealed that fluoride concentrations in 82 % of the 122 groundwater samples above the limit in drinking water as 1.0 mg/L in China. Fluoride in shallow groundwater (depth <20 m, ∼average = 2.08 mg/L) was mainly originated from fluorite dissolution and influenced by groundwater HCO3−, pH, and cation exchange levels. Below ∼200 m, the main source of groundwater fluoride (∼average = 3.12 mg/L) was the compression−release of clay pore water with high F− concentration, which was generated by complex water-rock interaction. Based on hydrochemical inverse simulation and end-member mixing models, the pore water released from clayey sediments supplied 53 %−56 % of deep groundwater (>200 m) and contributed 2.07 −2.87 mg/L to F− concentration. The findings of this study provide a theoretical basis for future research on prevention of high fluoride groundwater induced by clayey sediment compression.

Real-time predictive control assessment of low-water head hydropower station considering power generation and flood discharge

In the real-time operation of cascade reservoirs, when the discharge flow of the upstream power station changes frequently, the downstream power station with a low head and small storage capacity has to adjust the gate or turbine frequently to keep the water level safe. This paper proposes a real-time optimal scheduling model based on model predictive control theory(MPC), considering the interaction between power generation and flood discharge. Firstly, the correlation analysis is carried out between the outflow of the Zhentouba hydropower station(ZTB) and the inflow of the Shaping II Hydropower Station(SP), and the spatio-temporal hydraulic connection between the ZTB and SP is obtained. The fuzzy relationship between tail water level and discharge flow is accurately described using numerical simulation, considering the interaction between power generation and discharge. Secondly, based on the precise description of inflow and outflow, a high-precision water level rolling prediction model is constructed using the water balance principle. Finally, based on the MPC, the real-time control model of SP is constructed. The results show that the water level process is steadier, with fewer gate adjustments. Compared with the observed number of gate adjustments in 2020, the number of reservoir gate adjustments after model optimization is reduced by 73.26%. It improves the operation efficiency and safety of the hydropower station and provides a guidance basis for the optimal operation of the SP.

Study on flood level forecasting of tidal reach in Puyang River basin

Abstract The downstream section of the Puyang River is a tidal river reach subject to both upstream floods and downstream tides. This combined impact results in an unstable relationship between water level and discharge at the forecast station, making flood level forecasting challenging. This paper took the Linpu station on the Puyang River in Zhejiang Province as the research object. Based on the historical flood data, the cause of high water levels at Linpu station was analyzed. The flood levels at Linpu station were decomposed into flood increments and basic tidal levels. Using the multiple regression method, the prediction formula for upstream flood-induced water level increments was obtained. A flood level forecasting method based on the flood increment was developed. The result of the scheme accuracy evaluation indicates that this method has good forecasting performance. The flood level forecasting method for the tidal channel proposed in this paper has a simple structure and high accuracy, which provides a scientific basis for the prevention and control of flood and drought hazards and the decision-making of project scheduling in the tidal river.

Estimating Sediment Trap Efficiency of Flood Events During Flood Season in the Three Gorges Reservoir

AbstractSediment trapping significantly influences the comprehensive benefits of reservoirs and hinders the connection between sediment and nutrients in the upstream and downstream of rivers. Quantifying the role of sediment trapping by dams is important because this operation controls fluvial geomorphology, aquatic ecology, and water quality, particularly for flood processes with highly variable inflows. This study developed a new model to calculate the sediment trap efficiency (TE) of flood events during the flood season in the Three Gorges Reservoir (TGR) using a generalized theoretical approach. The TE of 55 flood events that occurred since the impoundment of the TGR were calculated and ranged from 16.0% to 99.8%, with a mean of 77.8%. Contrary to the previous understanding that large reservoirs have consistently large TE values based on long‐term data, our results show that large reservoirs can have a wide range of TE values during short‐term flood events. The proposed model estimates TE using three variables: inflow discharge, outflow discharge, and reservoir water level. Furthermore, the additional sedimentation risk to the TGR by optimized scheduling during the flood season is discussed. The results provide a reference for sedimentation management and optimal operation in the TGR.

Spring water discharge and metal enrichment in urban soils

Abstract Urban centers have inherited a unique mix of persistent contamination that impacts interactions among urban soil and groundwater systems. In particular, the potential for urban groundwater to transport contaminants from surface sources through the subsurface environment and ultimately to soils is not well understood. Studies have focused on specific ‘natural’ mechanisms driving distribution of metals in urban soils. However, very few studies have examined the accumulation of contamination in soils at groundwater discharge locations (springs) and the potential for groundwater to redistribute urban legacy contaminants far from the source. Soil transects straddling four groundwater springs in Pittsburgh, Pennsylvania were sampled to evaluate patterns resulting from contaminated groundwater discharge on urban soils. Metal concentrations were measured in pore water and compared with concentrations observed in total digestions and exchangeable extractions (acetic acid) of the soil. Across the springs Co, Cr, Ni, and V (metals often used in steel alloys) were elevated downslope, suggesting contaminated groundwater discharge enriches trace metals in these locations. These processes create unexpected biogeochemical patterns on the landscape and have the potential to create hotspots of soil metal contamination at predictable points across the urban landscape.

Assessment of the water quality in the coastal Yaqui valley (Mexico): implications for human health and ecological risks.

This study examines the water quality in the Yaqui Valley in Mexico, a semi-arid region impacted by mining, agriculture, and aquaculture. Contamination sources, health risks and ecological impacts are investigated. Freshwater was found to be contaminated by dissolved As, presumed to result from mining activities in the mountains. Drainage water revealed an overall contamination by dissolved As and by suspended particles enriched with Al, Fe and Mn, associated with runoff processes. Intermittent contamination of drainage water by Cu, K+, NO3- and PO43- is attributed to the use of fertilizers or pesticides. In the coastal area, drainage water contains high concentrations of Na, Ca, SO42- and Cl, related to salinization processes, as well as higher concentrations of dissolved As, related to solid/liquid interactions that are enhanced by salinization. This drainage water discharges into the bay, degrading the seawater quality and increasing ecological risks. Outputs of this study can serve as a reference for the protection of this economically important coastal ecosystem. Concerning health risks, this study demonstrates that groundwater is also contaminated by dissolved As, believed to be associated with transfers from the geological basement to the dissolved phase of water, and other major chemicals related to salinization processes. The findings indicate that ingesting the groundwater poses a significant risk to human health with a primary exposure risk associated with dissolved As, particularly among children. This study presents crucial data for the Yaqui population, water managers and researchers, and provides novel insights into the management and mitigation of the identified risks.

Water provision benefits from karst ecosystems: An example for Watuputih groundwater basin, North Kendeng Mountain, Indonesia

Karst ecosystems offer a wealth of ecosystem services, but their protection is increasingly challenging due to degradation and land-use conversion, including limestone mining. This study investigates the water provision service derived from karst ecosystems threatened by limestone mining in the Watuputih groundwater basin, Central Java, Indonesia. Water supply was quantified by measuring water discharge rates from major springs around the basin. Water usage was quantified for household consumption, agriculture, and recreation. This study also measured water infiltration rates in mining and non-mining areas to indicate the effects of limestone mining to hydrological processes. This study identified three primary springs around the basin: Sumber Seribu spring, Brubulan spring, and Kalutan spring, with discharge rates of 1,080 liters per second, 85 liters per second, and 0.76 liters per second, respectively. A local water company extracts water from Sumber Seribu spring at a rate of 80 liters per second to supply approximately 57,600 individuals. The water supply from the three springs can irrigate approximately 1,594 hectares of rice fields. Water from Sumber Seribu spring also supports recreational activities in Sumber Semen recreation park, attracting an average of 19,173 visitors per year. This study revealed a complete impairment of soil's water infiltration capacity in limestone mining areas. These findings underscore the pressing need to safeguard the Watuputih groundwater basin and to mitigate the detrimental effects of limestone mining on hydrological processes. This involves designating the Watuputih karst ecosystem as a protected area, implementing Payment for Ecosystem Services (PES) programs, and restoring degraded post-mining sites.

Highly efficient MIL-53(Al)@Biomass hybrid for oxytetracycline elimination: Adsorption, LED-induced photocatalysis and pyrolytic recycling

The presence of antibiotics in water discharges represents a hazard for the ecosystems, as it could affect the biota equilibrium at the micro and macroscales. Consequently, it is crucial to develop effective adsorption and oxidation technologies to remove antibiotics from water. Herein, we assessed the effectivity and stability of a metal organic framework-biomass hybrid (MIL-53(Al)@RH) for the removal of oxytetracycline (OTC) via adsorption and photocatalytic degradation. Under equilibrated conditions, the hybrid retained 165mgg−1 OTC. When adsorption and photocatalytic degradation were arranged in tandem, the system removed 99% of OTC with a dose of 2.83mg H2O2/mg OTC. The thermo-kinetic interpretation of the adsorption measurements was well described by Sip´s isotherm and pseudo-second kinetic models, which along with the heat of adsorption (−104.8kJmol−1) suggest a chemical interaction between the OTC and MIL-53(Al)@Rice Husk hybrid active centres. The MIL-53(Al)@RH hybrid demonstrated a remarkable stability with an OTC removal above 90% after 10 operational cycles. Moreover, pyrolysis of OTC-saturated hybrid led to a carbonaceous structure which demonstrated an outstanding OTC adsorption capacity (221mgg−1 OTC). The results demonstrate that the MIL-53(Al)@RH hybrid presents a significant prospect for combined adsorption-photocatalytic treatment of water bodies contaminated with antibiotics.

Soil erosion assessment using SWAT, in relation withLand use, agricultural practices, and future climate change in a semi-arid catchment in Tunisia

Abstract Soil erosion is a severe environmental concern arising from intensive agricultural uses, land degradation, and anthropogenic activities. This problem threatens agricultural productivity and sustainable development, particularly in emerging countries. Therefore, evaluating soil erosion is essential in conservation, planning, and management on a watershed or basin scale. This study aims to assess the erosion of soil loss in the El Gouazine Watershed, central Tunisia, using the Soil and water assessment tool (SWAT). We define the impact of soil and water conservation management implementation combined with climate change scenario. We identified the spatial distribution of erosion rates based on soil properties, topography, and land use. The observed specific erosion rate of the watershed is estimated at 1.6 t.ha−1.yr−1, whereas according to the SWAT model, the average soil loss rate is 1.4 t.ha−1.yr−1. Furthermore, the obtained results highlight importance of the slope factor in affecting the severity of the soil loss rates in the El Gouazine watershed. It was also demonstrated that it’s urgent to prioritize other measures such as contour cropping or conservation agriculture, to enhance and strengthen the soils’ resistance against the detachment due to discharge water. In this context, this research found that these techniques decrease considerably the soil loss by 22% for the strip cropping, 33% for the No-tillage, and 72% for the bench terracing. Moreover, these farming techniques, contribute at the same time to the amelioration of the water balance by reducing the evapotranspiration and enhancing the soil water storage. To go further in this study a soil erosion forecast using the worst-case scenario for climate change RCP 8.5 was conducted. an overview of the future soil erosion patterns is obtained. We noticed then a decrease of the average annual soil loss rate until 2050 and then a prominent increase from 2051 to 2100.