Water Discharge Research Articles

Effects of slag on mechanical and microstructural properties of iron-rich phosphoaluminate cement subjected to high temperature oil well environment

Iron-rich phosphoaluminate cement (shortened as PAC) exhibits excellent high temperature resistance characteristic, enabling it to withstand the ultrahigh temperatures required for the in situ combustion (ISC) of heavy oil. The addition of slag could influence its high temperature resistance by altering its hydration products. Hence the thickening time, physical properties, phase components and microstructure of PAC with slag that were subjected to different high temperature environment (315, 550 and 800 °C) were investigated deeply in this paper. The experimental analysis results revealed that PAC had better high temperature resistance than CAC with and without slag. The addition of slag improved effectively the high temperature resistance of PAC. The influencing mechanism of slag were as follows. C2ASH8 formed at 50 °C inhibited the conversion of C(A,P)H10 to C3AH6. C2AS3H, C3AS2H2 and C3(Fe,Al)S3 formed at 315 °C alleviated the rapid release of the compound water. The phase Ca5(PO4)3OH and C2AS was stable in the range of 550–800 °C. In addition, the capillary pore structure of PAC was optimized. Therefore, PAC with slag had the potential to be used for high temperature oil well cementing.

Łączność hydrologiczna, strukturalna i ekologiczna funkcjonalność meandrującego ekosystemu delty Dunaju

The pressure control of the climate change and anthropogenic factors have consequences on the ecological systems, generating structural changes. The abiotic (i.e., water hydrology and hydraulics, sediment load, water physic-chemistry) and biotic (i.e., biodiversity, structure and functionality of food webs) characteristics of river-channels-lakes from deltas depend on several factors; however, the main driver of these characteristics is represented by the hydrologic connectivity with the main stem of the river. Floodplain lakes can be permanently, temporarily or disconnected with the main stem of the river producing interruptions in the transfer of fresh water and thus affecting benthic macroinvertebrates, by decrease in their population, diversity and even loss of sensitive taxa. Multidisciplinary investigations (hydrodynamics, sedimentological and ecological measurements and analyses) were made to investigate a river-channel-lake site type situated on the St. George branch formed by a cutoff meander (Mahmudia meander), a connective channel (Uzlina Canal) and a lake (Uzlina Lake) to observe how much the fresh water and sediment input to the delta depressions is affected by the structural changes of the meander physiography. The Mahmudia meander was rectified 40 years ago and the response of the channel consisted in a very fast silting of the former meander, currently receiving less than 5% of the upstream water and sediment discharge. The lateral connectivity with the deltaic depressions thought the lateral canals is compromised.

Intelligent solar-driven “switch” photothermal hydrogel for clean water harvesting

Water shortage is becoming a huge challenge to mankind. Inspired by pufferfish, we developed an intelligent solar-driven “switch” hydrogel system PEG-PNIPAAm/Fe3O4 hydrogel (PPFH). This hydrogel system is characterized by a uniform porous network structure formed by the integration of hydrophilic PEG, temperature-responsive PNIPAAm polymer and Fe3O4 photothermal nanoparticles. The three-dimensional porous structure provides a higher surface area, offering more adsorption sites for water molecules. The interaction between PPFH and water primarily relies on the hydrogen bonding between the amide groups in PNIPAAm and water molecules, which enhances the hydration of the hydrogel network for rapidly water harvesting. However, when exposed to sunlight, the presence of Fe3O4 nanoparticles causes the ambient temperature to rise rapidly above the LCST, the hydrogen bonding between molecules gradually weakens, while the hydrophobic interactions among the hydrophobic groups in PNIPAAm become stronger, causing the polymer chains to contract and water releasing. The fog capture performance of PPFH can reach up to 3.2 g g−1, and under the irradiation of a sunlight (1 kW m−2), the captured water can be released within 8 min, and the water release efficiency reaches 94 %. This design concept provides the possibility for promoting the widespread implementation of hydrogels-based solar evaporators in practical purification systems in the future, alleviating water shortages issues.

Experiment and numerical simulation study of polycarboxylate superplasticizer modified cemented ultrafine tailings filling slurry: Rheology, fluidity, and flow properties in pipeline

Understanding the rheological properties of cemented paste backfill is crucial for optimizing its flowability and ensuring the efficient transportation in mine site. Due to the superfine size, the high-concentration filling slurry prepared by ultrafine tailings (the mean size < 0.019 mm) usually exhibits poor flow performance. In this study, the polycarboxylate superplasticizer (PCS) was adopted as an additive to modify cemented ultrafine tailings filling slurry. Experiment tests and numerical simulation were conducted to investigate effects of PCS dosages, solid and binder contents on rheological, fluidity, and flow performance. Results indicate that the PCS modified filling slurry conforms to Bingham model and shows shear-thinning behavior. As PCS dosage increases from 0 to 0.30 wt%, the yield stress gradually decreases, whereas the plastic viscosity initially increases then decreases. The electrostatic repulsion and steric hindrance generated by PCS can disintegrate the floc structures formed by ultrafine particles, leading to more release of free water, and reducing interparticle friction, correspondingly, improving flowability of filling slurry. The optimal PCS dosage is determined as 0.15–0.25 wt% considering transportation requirement. For a given PCS dosage, the yield stress and plastic viscosity exhibit an exponential growth with solid content, while a continuous decline with binder content. Furthermore, the fluidity increases linearly and exponentially with PCS dosage for filling slurry at solid content of 59–62 wt% and 63 wt%, respectively. An exponential model is established to quantify the relationship between yield stress and fluidity, which provides a method for predicting rheological parameters. With addition of PCS dosage, the flow performance of filling slurry is enhanced significantly in transportation pipeline. The maximal flow velocities at the pipeline center increase, and those near the pipeline wall decrease. The findings afford a practical guidance for designing and optimizing materials proportions of PCS modified filling slurry to achieve the desired flowability in mine site.

Optimization and Modelling to Enhance Hydroturbine Performance

In this study, a new design of a hydroturbine was developed, modelled, and constructed. The unique features of this turbine design required a thorough investigation and optimization process to enhance hydroturbine performance. The paper discusses numerical and experimental results obtained on the hydroturbine. The optimal angle of attack for the inlet flow direction has been computed from numerical modelling. Consequently, data on velocity, pressure, lift, and drag forces along the blade have been obtained. The study also takes into account the operation of the hydroturbine under non-rotating and rotating rotor modes. Performance metrics such as head, torque, hydraulic power, hydroturbine power, and efficiency were then calculated based on water discharge. These performance calculations were conducted using COMSOL Multiphysics, employing Direct Numerical Simulation and k-epsilon methods. Numerical calculations offer a cost-effective approach to reducing the financial burden associated with material costs for manufacturing hydroturbine prototypes.

Pengaruh Penerapan Sistem IPAL terhadap Kulitas Air Buangan Rumah Pemotongan Hewan

PT X is a company engaged in animal slaughtering and produces liquid waste in the process of its activities. Located in Banyuwangi Regency, East Java Province, this study aims to determine the effect of the implementation of the Wastewater Treatment Plant (WWTP) system on the quality of PT X's wastewater. The effect of implementing the WWTP system can be measured through baseline data collection, evaluation of WWTP effectiveness, observation of WWTP operation and maintenance, and recommendations in accordance with the Regulation of the Minister of Environment and Forestry of the Republic of Indonesia Number 68 of 2016 concerning Domestic Wastewater Quality Standards. Pollutant parameters in wastewater include BOD, COD, TSS, and O&amp;G (Oil &amp; Grease) that exceed the quality standards. After the implementation of the WWTP system, the effluent results showed a decrease and no longer exceeded the quality standards, proving that the implemented WWTP system has a positive effect on the quality of the PT X abattoir discharge water.

Saline mine water influences eukaryote life in shallow groundwater of a tropical sandy stream

Eukaryotic communities in groundwater may be particularly sensitive to disturbance because they are adapted to stable environmental conditions and often have narrow spatial distributions. Traditional methods for characterising these communities, focussing on groundwater-inhabiting macro- and meiofauna (stygofauna), are challenging because of limited taxonomic knowledge and expertise (particularly in less-explored regions), and the time and expense of morphological identification. The primary objective of this study was to evaluate the vulnerability of eukaryote communities in shallow groundwater to mine water discharge containing elevated concentrations of magnesium (Mg) and sulfate (SO4). The study was undertaken in a shallow sand bed aquifer within a wet-dry tropical setting. The aquifer, featuring a saline mine water gradient primarily composed of elevated Mg and SO4, was sampled from piezometers in the creek channel upstream and downstream of the mine water influence during the dry season when only subsurface water flow was present. Groundwater communities were characterised using both morphological assessments of stygofauna from net samples and environmental DNA (eDNA) targeting the 18S rDNA and COI mtDNA genes. eDNA data revealed significant shifts in community composition in response to mine waters, contrasting with findings from traditional morphological composition data. Changes in communities determined using eDNA data were notably associated with concentrations of SO42−, Mg2+ and Na+, and water levels in the piezometers. This underscores the importance of incorporating molecular approaches in impact assessments, as relying solely on traditional stygofauna sampling methods in similar environments may lead to inaccurate conclusions about the responses of the assemblage to studied impacts.

Effects of deep coal mining on groundwater hydrodynamic and hydrochemical processes in a multi-aquifer system: Insights from a long-term study of mining areas in ecologically fragile western China

The groundwater hydrodynamic and hydrochemical process of the multi-aquifer system will experience complicated and serious influence under deep coal mining disturbance. There is relatively little research that has integrated hydrodynamic and hydrochemical properties of groundwater to investigate the spatiotemporal distribution characteristics and evolution patterns of hydrogeochemistry and hydrodynamic information in deep multi-aquifer systems. The study of the groundwater hydrodynamic and hydrochemical spatiotemporal coupling response of multi-aquifer systems under the deep and special thick coal seam mining-motivated effect in ecologically fragile western mining areas is of great significance for the safe mining of coal resources and ecological environment protection. In this research, the hydrochemical analysis data composed of 218 groundwater samples from Tangjiahui coalfield, Northwest China with 1526 measurements and a 6-year (2016–2021) sampling period were collected for studying the hydrogeochemical spatiotemporal evolution process and governing mechanism of the multi-aquifer system using hierarchical cluster analysis, ion-ratio method, saturation index and multidimensional statistical analysis. Additionally, wavelet analysis and cross-wavelet coherence analysis were implemented to quantitatively recognize the spatiotemporal variation characteristics of hydrodynamic information and analyze the coherence relationships between time series. The results demonstrate that the hydrochemical characteristics exhibit significant spatial differences, while the temporal variation of hydrochemical characteristics in the Permian Shanxi Formation fractured sandstone aquifer (PSFFA), mine water (MW), and Ordovician karst limestone aquifer (OKA) is not significant. The water-rock interaction is the predominant control mechanism for the spatial evolution of hydrogeochemistry in the research area. Moreover, the large-scale mining of deep coal seams controls the type and degree of water-rock interactions by damaging the structure of aquifers and altering the hydrodynamic conditions of groundwater. The period from 2016 to 2021 exhibits multi-time scale characteristics in time series of precipitation, mine water discharge, and the water level of PSFFA and OKA. The mine water discharge has a positive correlation with the water level of PSFFA and OKA, whereas the significant period of precipitation and the water level of PSFFA coherence is not obvious. The research findings not only provide in-depth insights to protect the groundwater resources in water-shortage mining areas but also promote the secure mining of deep coal resources.

Computational Fluid Dynamics Modelling of the Temperature Distribution in Power Plant's Cooling Canal

Seawater used as a heat exchanger in the coal-fired power plant condenser system has a higher water temperature than the natural temperature of seawater. There was an increase in the temperature of the waters around the coal-fired power plant due to the discharge of boiling water reaching 6.50C. According to the regulations in force in Indonesia, the hot water temperature at the water discharge outlet should not be more than 20C of the natural temperature of seawater. The purpose of this study is to predict the pattern of temperature decrease in the temperature of the boiling water along the cooling line. The method used to predict temperature drop patterns along the cooling line uses a 3-dimensional CFD (Computational Fluid Dynamics) modelling approach with the Ansys Fluent 2023 RI application. The K-Epsilon turbulence model was chosen to describe the effect of flow turbulence on temperature changes. The modelling results were validated by comparing the actual measurements of the water temperature field data representing along the cooling line. The results showed that the performance of reducing the temperature of the water increased when passing through the cascade aeration downstream of the channel. The flow of water along the channel tends to be on the lower side, and downstream, the flow is on the left–middle side. The error calculation using MAPE resulted in 9.49%.

Tailoring the covalent organic frameworks based polymer materials for solar-driven atmospheric water harvesting

Atmospheric water harvesting through reticular materials is an innovation that has the potential to change the world. Here, this study offers a technique for creating a solar-powered hygroscopic polymer material for atmospheric water harvesting with the reticular materials. The results show that the porous hygroscopic polymer materials can achieve high performance with high vapor capture (up to ac. 28.8–49.7 mg/g at 28–38 %RH and 25 ℃), rapid photothermal conversion efficiency (up to 32.2 ℃ within 15 min under 1000 W/m−2 light at 25 ℃), a low desorption temperature (lower than 40 ℃), and an effective water release rate. Besides, the material also has excellent water-retention properties, which can effectively store desorbed liquid water in polymer networks for use by vegetation during water demand periods. The strategy opens new avenues for atmospheric water-harvesting materials, which will hopefully solve the global crisis of freshwater shortages.

Water Accounting

The urgent solutions required to avoid the increasingly frequent floods and droughts and many other issues regarding water access and management made water a subject that has attracted the attention of many – as they did with accounting professionals. Since businesses are among the largest consumers of freshwater worldwide, corporate engagement with water issues is required to safeguard the organization’s license to operate. Corporate Water Accounting then allows companies to determine the impacts of their water use and discharges on communities and ecosystems, evaluate their water-related material risks, track the effects of changes in their water management practices, and credibly report them to their stakeholders. Therefore, this theoretical essay addresses water issues within the accounting field by recognizing three interrelated approaches that drive corporate water accounting implementation - Water Risk, Water Resources Management, and Water Reporting. We acknowledge its concepts, some useful tools, and its most concerning challenges while tracing its current state, especially in Brazil, and our future expectations for water accounting development. Furthermore, based on the theoretical contributions discussed, we point out some challenges managers face and future research opportunities. We expect more accounting professionals and researchers to engage with corporate water accounting to overcome the gaps that challenge the field's development.

Dewatering performance of aerobic granular sludge under centrifugal with different sludge conditioning agent.

The aerobic granular sludge(AGS) technology draw scientific researchers attention, and more and more scientific research focuses on it, due to its superior advantages, such as good settling performance, high biological phase, high toxicity resistance and multiple biological effects. With the rapid development of AGS technology, a considerable amount of residual AGS will be produced, and dehydration is the biggest bottleneck of sludge reduction. This study investigated the dewatering process and method of residual AGS cultured by continuous flow experiment. Experiments were conducted using centrifugal dewatering technology with a dosing scheme to analyze the granular sludge dewatering process, and investigate the release process of EPS component in AGS dewatering. Our results implied the specific resistance of AGS has a very low value ((1.82 ± 0.03) × 109 m/kg) and it was not obvious for the conditioning effect of chemical conditioner on AGS dewatering. However, the moisture content can be reduced to 63.5% after dewatering with the presence of inorganic substances. The addition of drinking water treatment plant sludge (Alum sludge) can improve the efficiency of the dewatering of AGS. A possible dewatering process of AGS dewatering was proposed which was divided into two stages: First, a considerable amount of free water in the sludge was quickly removed under the action of gravity without pressure filtration. Second, the bound water release required cooperation between applying centrifugal or pressing force to grind granular cells and separate protein-like substances with the inorganic matter inside the granular sludge. The possible mechanism of AGS dewatering and hypothesis dewatering process are useful to optimize the AGS dewatering process.

Determination of the WQI Index to Evaluate the Water Quality of the Monjas River located in Quito

The study of water quality is important over time because it is an essential element for human beings, it has been vital for their survival, territorial expansion, and socioeconomic development. The water of the Monjas river present contamination issues, mainly due to human activities such as agriculture, animal husbandry, and gray water discharges that alter their chemical, biological, and physical properties. The purpose of this research is to evaluate whether the water conditions are suitable for agricultural use, applying the Water Quality Index (WQI) methodology, which requires a study in the laboratory for fecal coliforms, dissolved oxygen, pH, biological demand for oxygen, nitrates, phosphates, dissolved solids, turbidity, and temperature. Samples were taken at six sampling points along the riverbed. Results were compared with the parameters described by TULSMA (Texto Unificado de la Legislación Secundaria de Ministerio de Ambiente), and FAO (The Food and Agriculture Organization of the United Nations) environmental regulations. Higher values were obtained for fecal coliforms, and biochemical oxygen demand that exceeded the maximum permissible limits with respect to the rest of the parameters examined. In this study, the WQI ranged from 26 to 50, classifying the water quality of the Monjas river as unsuitable. It implies that it is not appropriate for agricultural use due to the contamination that it could cause to the crops. The main reasons for this could rely on the presence of fecal matter of human, and animal origin, fertilizers, pesticides, and household waste.

Dewatering and valorizing lake sediments by electroosmotic dewatering for lakes restoration.

Dredging eutrophic lake sediments can improve water quality, but it also requires dewatering and valorizing the dredged material to avoid wasting resources like phosphorus. This study experimentally investigated the basic mechanism and performance of electroosmotic dewatering of 1-L dredged sediments using different electric currents (20mA, 40mA, and 60mA) after gravity filtration. The dewatering performance, moisture content and distribution, effect of electrochemical reaction on dewaterability, energy consumption, and changes in metals and phosphorus (P) distribution and pH values were analyzed. The results indicated that electroosmotic dewatering effectively decreased sediment mass by predominantly eliminating free and a portion of interstitial water, with reductions ranging from 7 to 20%. The optimal duration and current should, however, be considered to balance water removal and energy consumption. Higher moisture removal occurred with 40mA for 24h and 60mA for 6h, while the energy consumption obtained with 60mA (0.201 kWh/kg water removed) was significantly lower than that of applying 40mA for 24h (0.473 kWh/kg water removed), with the assistance of ohmic heating, resulting in reduced viscosity and water release from capillaries. The tested conditions did not significantly extract heavy metals or P from the sediments, which may facilitate the disposal of the removed water back into the lake and the utilization of the treated sediments for different purposes. This technology is easy to operate and suitable for the treatment of dredged sediments, and the dewatering result is comparable to low pressurized filtration but at low energy consumption.

Flow Patterns Modeling over Spillway: Review Study

A spillway dam, constructed concurrently with concrete or masonry, is a vital infrastructure designed to provide the controlled release of surplus water that surpasses the dam's storage capacity. Since the Ogee spillway is among the best and most well-known worldwide, it deserves study. Weir flow, inertia, and gravity are crucial in many open-channel applications. Consequently, hydraulic performance data between model and prototype structures are commonly scaled using Froude similitude. As the upstream head decreases in a weir flow, the surface tension and viscosity forces become more important, perhaps to the point where Froude scaling fails to achieve complete model-prototype similarity. Size-scale effects are responsible for various alterations to the head-discharge connection, the nappe trajectory, and air entrainment. Hydraulic parameters were explored in this work utilizing Flow3D software to find weir geometry optimization using the CFD method. In addition, this study attempted to evaluate flow on various parts of crested weirs in three different models.

Electroosmotic strengthening of soft clay under different electrification modes

AbstractElectrification mode is one of the important factors affecting the energy consumption and drainage effect of the electroosmosis method. In this work, a series of laboratory tests were performed to explore the impact of continuous changes in the electric field on the migration of ions and electrons, as well as the migration of electroosmotic flow. The results show that different electrification modes had a significant impact on the current and water discharge. An electrode reversed from anode to cathode, from one circuit to another, is beneficial to drainage, while an electrode reversed from cathode to anode, from one circuit to another, is unfavorable to drainage. The drainage effect of the specific cyclic and progressive electroosmosis (CPE) is not as good as the conventional electroosmosis method. However, combining the two electrification modes can further enhance the shear strength of the soil near a designated electrode. The generation of transverse cracks in soil is mainly due to the drainage difference caused by the electroosmotic flow, which is caused by the adjacent electric field at that location. When the electroosmotic flow is strong, longitudinal cracks will occur in the soil along the strongest electroosmotic flow path. In practical in situ engineering applications, the electrification mode of CPE will be more energy‐efficient than conventional electrification modes with the same processing time.

Study on Alkali Reduction Effect of SAP on Cementitious Composites

In order to improve the high alkalinity environment inside the cementitious composites, the effect of SAP doping on the pH value and compressive strength of cement slurry was investigated by doping Super Absorbent Polymer (SAP). The test results show that SAP can reduce the pH value of cementitious composites at 28d to a certain extent; the pH value of cementitious composites at 28d is significantly reduced when SAP doping is 0.3%, and the compressive strength is improved compared with that of the control group; SAP particles will form cracks with the middle of the cement matrix after the release of water to reduce the alkaline material outflow from the cement matrix, which will make the pH value of SAP specimens reduced.

Synthesis of a superabsorbent hydrogel from Artocarpus heterophyllus Lam seed polysaccharides and its application in relieving drought stress in plants

AbstractSustainability in agriculture can only be achieved by protecting important resources, one of them being water. Availability of water in the soil greatly influences agricultural productivity. Hydrogels play a key role in ensuring water availability and achieving agricultural sustainability. A novel superabsorbent hydrogel was synthesized from Artocarpus heterophyllus Lam seed polysaccharides. The synthesized hydrogel was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, and scanning electron microscopy. Swelling capacity of the hydrogel in different solutions, water retention duration, its influence on the soil water holding capacity (SWHC), and degradation in soil were assessed. The hydrogel absorbs up to 326 g/g and degrades naturally at around 1.4 wt% daily. The hydrogel improved the SWHC by 34% at a concentration of 0.3% w/w. Further pot experiments with black gram (Vigna mungo (L.) Hepper) plants showed that the superabsorbent hydrogel ensured water availability for 35 days and relieved the plants from drought‐induced stress. The data presented here indicates that the synthesized hydrogel can potentially be used as a soil conditioner for the sustained release of water and fertilizer.

Ship scheduling problem in an anchorage-to-quay channel with water discharge restrictions

The optimization of ship scheduling in water-land transshipment plays a crucial part in enhancing transportation efficiency and alleviating traffic congestion on inland waterways, particularly when the service capacity of locks is insufficient. This study focuses on the ship scheduling problem in an anchorage-to-quay channel, where the navigation of ships is influenced by the water discharge during flood seasons. A new mixed-integer linear programming (MILP) model is formulated for this problem, in which the interconnected decision of ships’ navigation and berthing activities, the variation of water discharge in the waterway channel, and the change of navigation scenarios (i.e., normal or flood impact) are explicitly taken into account. Then a multi-population genetic algorithm (MPGA) is applied to solve this model. Numerical experiments conducted for the Three Gorges Dam (TGD) demonstrated that the proposed heuristic method can tackle the ship scheduling problem within a reasonable time, which is also effective in assisting ships to match acceptable water discharge time window by slightly adjusting the departure time of ships at the anchorage or quay. Furthermore, the proposed method can ensure the navigational safety of ships and improve the efficiency of ship transportation in different scenarios, and quantitatively evaluate the water discharge impact.

Reflection of Daily, Seasonal and Interannual Variations in Run-Off of a Small River in the Water Isotopic Composition (δ2H, δ18O): A Case of the Ala-Archa Mountain River Basin with Glaciation (Kyrgyzstan, Central Asia)

Small intermountain river basins are most suitable for developing new methods to estimate water balance due to their well-defined catchment boundaries, relatively rapid runoff processes, and accessible landscapes for study. In general terms, dissecting the hydrograph of a small mountain river requires calibration of the flow model against multi-year data sets, including (a) glacier mass balance and snow water content, (b) radiation balance calculation, (c) estimation of the groundwater contribution, and (d) water discharge measurements. The minimum primary data set is limited to the precipitation and temperature distributions at the catchment. This approach postulates that the conditions for the formation of all components of river flow are known in advance. It is reduced to calculating the dynamic balance between precipitation (input part) and runoff, ablation, and evaporation (output part). In practice, accurately accounting for the inflow and outflow components of the balance, as well as the impact of regulating reservoirs, can be a challenging task that requires significant effort and expense, even for the extensively researched catchments. Our studies indicate the potential benefits of an approach based on one-time, but detailed, observations of stable isotope composition, temperature, and water chemistry, in addition to standard datasets. This paper presents the results of the 2022–2023 work conducted in the basin of the small mountain river Ala-Archa, located on the northern slope of the Kyrgyz Range in Tien-Shan, which was chosen as an example due to its well-studied nature. Our approach could identify previously unknown factors of flow formation and assess the time and effectiveness of work in similar conditions.