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Volume 15
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Water, Volume 15, Issue 22 (November-2 2023) – 161 articles

Cover Story (view full-size image): CESER GCRD scientists Catherine Clark and Lee K. Rhea published a paper on cometabolism of 1,4-dioxane and chlorinated solvents titled “Cometabolism of Chlorinated Volatile Organic Compounds and 1,4-Dioxane in Groundwater” in the MDPI journal Water. This literature review summarizes laboratory studies on the biochemical processes of cometabolism as well as pilot and full-scale field demonstrations that utilize cometabolism to biodegrade 1,4-dioxane and chlorinated solvents. A review of these studies can help to determine whether cometabolism is the right treatment method for a 1,4-dioxane and chlorinated solvent plume and how to facilitate and monitor degradation via this process. View this paper
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14 pages, 4566 KiB  
Article
Optimization Research on the Space-V-Type Biomimetic Surface Grooves of a Marine Centrifugal Pump
by Hua Li, Zifeng Yu, Runan Hua, Chenqi Li, Chao Guo, Houlin Liu and Liang Dong
Water 2023, 15(22), 4031; https://doi.org/10.3390/w15224031 - 20 Nov 2023
Viewed by 1192
Abstract
The biomimetic surface with Space-V grooves can effectively reduce flow resistance and noise. Our investigation was in order to further enhance the drag reduction and noise reduction performance of a marine centrifugal pump with Space-V-groove-shaped biomimetic surfaces. A regression equation was established with [...] Read more.
The biomimetic surface with Space-V grooves can effectively reduce flow resistance and noise. Our investigation was in order to further enhance the drag reduction and noise reduction performance of a marine centrifugal pump with Space-V-groove-shaped biomimetic surfaces. A regression equation was established with response surface methodology between the total sound pressure level and the height (h), width (s), and spacing (b) of the biomimetic groove structure. The interaction effects of various parameters on the total sound pressure level were analyzed, and the parameter range was determined at the lowest total sound pressure level. The hydraulic performance and interior noise of the model before and after optimization were compared. The results showed that the total sound pressure level initially decreased and then increased with increasing groove height. Similarly, with an increase in groove width, the total sound pressure level decreased at first, then increased. When the height of the bionic groove is 0.5–0.7 mm, the groove width is 0.4–0.7 mm, the groove spacing is 0.7–1.3 mm, and the total sound pressure level of the centrifugal pump is the smallest, which is 180–182 dB. On the other hand, the total sound pressure level increased as groove spacing increased. Through the use of an optimized Space-V groove model, under rated working conditions, the model head is increased by 0.27 m and the efficiency is increased by 1.21%. In addition, the optimized model has excellent drag and noise reduction performance, with the drag reduction rate of 3.73% and noise reduction rate of 1.81%, which are, respectively, increased by 0.87% and 0.45% compared with before optimization. The performance of centrifugal pumps for ships can be greatly improved. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery)
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14 pages, 2779 KiB  
Article
Evolutionary Trends and Coordinated Development Analysis of Water Resources Systems and High-Quality Economic Growth in the Yangtze River Delta
by Di Liu, Qin Dai and Guanghui Yuan
Water 2023, 15(22), 4030; https://doi.org/10.3390/w15224030 - 20 Nov 2023
Cited by 1 | Viewed by 1345
Abstract
This article calculates the indices for high-quality economic development and water resource systems across 25 cities in the Yangtze River Delta from 2011 to 2021. Utilizing a multifaceted analytical framework comprising the CRITIC method, standard deviation ellipse, harmonious development coefficient, and coupling coordination [...] Read more.
This article calculates the indices for high-quality economic development and water resource systems across 25 cities in the Yangtze River Delta from 2011 to 2021. Utilizing a multifaceted analytical framework comprising the CRITIC method, standard deviation ellipse, harmonious development coefficient, and coupling coordination coefficient, we investigate spatiotemporal evolutionary trends and overarching harmonious development states between the two systems. Results indicate: (1) Throughout the research period, mean values of high-quality economic development indices fluctuated within the range of 0.05 to 0.68, while water resource carrying capacity indices oscillated between 0.18 and 0.81. (2) The epicenter of high-quality economic development indices is situated in the periphery of Lake Tai, whereas the fulcrum of the water resource system indices is located in Huzhou City, both displaying a northwest-southeast orientation. (3) Coupling coordination development exhibits a propitious advancement trajectory, with certain locales attaining exemplary coordinated growth. Full article
(This article belongs to the Special Issue Reservoir Control Operation and Water Resources Management)
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19 pages, 1341 KiB  
Article
Investigating the Influence of the Relative Roughness of the Riverbanks to the Riverbed on Equilibrium Channel Geometry in Alluvial Rivers: A Variational Approach
by Jinsheng Fan, Qiushi Luo, Yuchuan Bai, Xiaofang Liu and Renzhi Li
Water 2023, 15(22), 4029; https://doi.org/10.3390/w15224029 - 20 Nov 2023
Viewed by 1381
Abstract
The roughness of a river’s boundary significantly influences the sediment transport process and the ultimate configuration of the river’s stable cross-section. This interplay between boundary roughness and river morphology is crucial to a river’s overall behavior and form. This study aims to analyze [...] Read more.
The roughness of a river’s boundary significantly influences the sediment transport process and the ultimate configuration of the river’s stable cross-section. This interplay between boundary roughness and river morphology is crucial to a river’s overall behavior and form. This study aims to analyze the influence of the relative roughness of riverbanks to a riverbed λ on the equilibrium form of alluvial rivers using a variational method. The results show the following: (1) As the parameter λ transitions from smaller to larger values, noteworthy variations are observed in a river’s characteristics. Specifically, there is a discernible reduction in the calculated maximum sediment discharge, coupled with a corresponding expansion in the optimal width–depth ratio. For instance, when λ changes from 1 to 0.1, the optimal width–depth ratio increases by 45%, while the calculated maximum sediment discharge experiences a decrease of 1.62%. (2) An examination of hydraulic geometric relationships, derived by assigning distinct values to the relative roughness of riverbanks to the riverbed, highlights the significant influence of this relative roughness on the ultimate equilibrium configuration of the river channel. Remarkably, this effect remains consistent and stands independently of other variables such as sediment discharge, flow discharge, channel gradient, and sediment size. (3) The critical and average hydraulic geometric relationships deduced in this study closely align with previous research findings. Notably, this research contributes to addressing the existing gap in understanding the mechanistic underpinnings of how river boundary conditions impact the equilibrium forms of rivers, thereby advancing our knowledge of river morphology. Nevertheless, it is imperative to emphasize that while this study provides valuable theoretical insights, the practical application of these findings in the context of river morphological evolution necessitates further in-depth research. It calls for a more comprehensive exploration of the transition from theoretical constructs to real-world applications, thus promoting a deeper understanding of the dynamics that shape river systems. Full article
(This article belongs to the Special Issue Fluvial Systems and River Geomorphology)
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18 pages, 6328 KiB  
Article
Comparison of Pressure Pulsation Characteristics of Francis Turbine with Different Draft Tube Arrangement Direction
by Tao Zhang, Zilong Hu, Xinjun Liu, Jiahao Lu, Xijie Song, Di Zhu and Zhengwei Wang
Water 2023, 15(22), 4028; https://doi.org/10.3390/w15224028 - 20 Nov 2023
Viewed by 1452
Abstract
Hydroelectric power generation is an important clean energy source, and the stability of water turbine operation determines the quality of hydro energy utilization. For hydro turbines, the layout direction of the draft tube is often only considered from a structural perspective, ignoring the [...] Read more.
Hydroelectric power generation is an important clean energy source, and the stability of water turbine operation determines the quality of hydro energy utilization. For hydro turbines, the layout direction of the draft tube is often only considered from a structural perspective, ignoring the hydrodynamic characteristics. This study adopts the computational fluid dynamics method and verifies the effectiveness of numerical simulation with experimental results, analyzing the influence of asymmetric draft tube layout direction on pressure pulsation of mixed flow turbine. The results show that under different working conditions, there is basically no difference in efficiency corresponding to different inclined directions of the draft tube, and the relative difference in performance values is less than 1%. From the perspective of internal flow, the working condition has a greater impact on the flow, and the draft tube tilt has a smaller impact. Under strong swirling flow conditions in the draft tube, the variational mode decomposition of pressure fluctuation is carried out. Research has found 7 characteristic frequency bands including 140 Hz, 80–90 Hz, 40–46 Hz, 5.5–6.5 Hz, 2.5–3 Hz, 1.67 Hz, and <1 Hz. The frequency of the dominant mode corresponding to the left tilt is higher, while the amplitude of the runner frequency is slightly lower. In general, left tilt is not only more suitable for unit layout but also has a better effect on draft tube pressure fluctuation, which is worthy of application in engineering. Full article
(This article belongs to the Special Issue Advances in Hydrodynamics of Water Pump Station System)
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12 pages, 2176 KiB  
Article
Rapid Antibiotic Adsorption from Water Using MCM-41-Based Material
by Jie Chen, Yao Yang, Yuanyuan Yao, Zhujian Huang, Qiaoling Xu, Liping He and Beini Gong
Water 2023, 15(22), 4027; https://doi.org/10.3390/w15224027 - 20 Nov 2023
Viewed by 1629
Abstract
The contamination of antibiotics in the environment has raised serious concerns, impacting both human life and ecosystems. This has led to a growing focus on the development of cost-effective and environmentally friendly adsorbent materials. Mesoporous molecular sieve MCM-41, known for its strong adsorption [...] Read more.
The contamination of antibiotics in the environment has raised serious concerns, impacting both human life and ecosystems. This has led to a growing focus on the development of cost-effective and environmentally friendly adsorbent materials. Mesoporous molecular sieve MCM-41, known for its strong adsorption capacity, low cost, and efficient regenerative properties, holds significant promise for addressing this issue. In this study, we investigated the adsorption behavior of demolded MCM-41 materials in relation to tetracycline, doxycycline, and levofloxacin at different temperatures and pH levels. Our experiments encompassed the adsorption of these three common antibiotics, revealing that a neutral or weakly acidic pH environment promoted adsorption, whereas alkaline conditions hindered it. Utilizing the equilibrium isotherm model, we determined the theoretical maximum adsorption capacities for tetracycline (TC), doxycycline (DOX), and levofloxacin (LFX) as 73.41, 144.83, and 33.67 mg g−1, respectively. These findings underscore the significant potential of MCM-41 in mitigating antibiotic wastewater contamination. Full article
(This article belongs to the Special Issue Water Resources and Sustainable Development)
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20 pages, 13939 KiB  
Article
Evaluation of the Radon Levels in the Groundwater Wells of Qatar: Radiological Risk Assessment
by Yehia Manawi, Ayesha Ahmad, Mosab Subeh, Mohammad Hushari, Sayed Bukhari and Huda Al-Sulaiti
Water 2023, 15(22), 4026; https://doi.org/10.3390/w15224026 - 20 Nov 2023
Cited by 6 | Viewed by 1895 | Correction
Abstract
The objective of this work is to give a holistic overview of the groundwater quality in Qatar in terms of its radon levels and provide a radiological risk assessment of elevated radon levels on human health. This study covered the analysis of groundwater [...] Read more.
The objective of this work is to give a holistic overview of the groundwater quality in Qatar in terms of its radon levels and provide a radiological risk assessment of elevated radon levels on human health. This study covered the analysis of groundwater collected from various locations throughout Qatar and maps using ArcGIS followed by a radiological risk assessment of radon in Qatar. There is no extensive study reported to investigate radon activity levels in groundwater across Qatar and their health effects. The radon level measurements of the Qatari groundwater ranged between 2.7 ± 0.2 and 60.7 ± 13.4 Bq/L with a mean value of 20.6 Bq/L, which is greater than the US EPA’s maximum contamination level (11 Bq/L). About 65% of the studied samples exceeded the US EPA’s MCL guidelines. The mean total annual effective dose due to radon inhalation and ingestion was 0.056 mSv/y, which is below the WHO reference level of 0.1 mSv/y. The radon radiological risk study through inhalation and ingestion clearly revealed that the contribution of the inhalation dose was higher than the ingestion dose. Full article
(This article belongs to the Section Water Quality and Contamination)
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15 pages, 5942 KiB  
Article
Vulnerability Assessment and Future Prediction of Urban Waterlogging—A Case Study of Fuzhou
by Xuerao Wang, Zhiming Zhang, Wenhan Hu, Xin Zhao, Xiaotian Qi and Ran Cai
Water 2023, 15(22), 4025; https://doi.org/10.3390/w15224025 - 20 Nov 2023
Cited by 1 | Viewed by 1638
Abstract
Evaluating waterlogging vulnerability and analyzing its characteristics and future trends can provide scientific support for urban disaster prevention and reduction. For this study, taking Fuzhou as an example, an urban waterlogging vulnerability assessment system was constructed from the three dimensions of exposure, sensitivity, [...] Read more.
Evaluating waterlogging vulnerability and analyzing its characteristics and future trends can provide scientific support for urban disaster prevention and reduction. For this study, taking Fuzhou as an example, an urban waterlogging vulnerability assessment system was constructed from the three dimensions of exposure, sensitivity, and adaptive capacity. The entropy method was used to evaluate urban waterlogging vulnerability in Fuzhou during 2014–2020. The use of CA–Markov to predict waterlogging vulnerability in 2023, 2026, and 2029 in Fuzhou is an important innovation reported in this paper. Study results showed that: (1) Vulnerability to waterlogging in Fuzhou follows a gradually decreasing “center-southeast” distribution pattern, with Level 5 areas mainly located in Cangshan District, Gulou District, and Taijiang District. (2) Changes in waterlogging vulnerability in Fuzhou from 2014 to 2020 can be divided into five change modes, with changing areas, mainly of the late-change type, accounting for 14.13% of the total area. (3) Prediction accuracy verification shows that the CA–Markov model is suitable for predicting waterlogging vulnerability in Fuzhou with high accuracy and a kappa coefficient of 0.9079. (4) From 2020 to 2029, the vulnerability level of the eastern coastal region of Fuzhou is expected to generally increase, and the vulnerability degree will continue to deteriorate. The proportion of Level 5 vulnerable areas will increase by 4.5%, and the growth rate will increase faster and faster with the passage of time. Full article
(This article belongs to the Special Issue Urban Water Management and Hydrological Process)
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19 pages, 7484 KiB  
Article
Groundwater Hydrogeochemical Processes and Potential Threats to Human Health in Fengfeng Coal Mining Area, China
by Zhiqiang Zhang, Haixue Li, Fawang Zhang, Jiazhong Qian, Shuangbao Han and Fenggang Dai
Water 2023, 15(22), 4024; https://doi.org/10.3390/w15224024 - 20 Nov 2023
Cited by 1 | Viewed by 1282
Abstract
The Fengfeng mining area is in the transition zone between the North China Plain and the Taihang Mountains, and groundwater is the main source of water supply in the district. Under the combined influence of human activities and natural geological conditions, the quality [...] Read more.
The Fengfeng mining area is in the transition zone between the North China Plain and the Taihang Mountains, and groundwater is the main source of water supply in the district. Under the combined influence of human activities and natural geological conditions, the quality of different types of groundwater varies greatly, posing a potential threat to the safety of drinking water. In this study, hydrogeochemical processes in different types of groundwater were analyzed using multivariate statistical analysis methods with ion–ratio relationships, and a groundwater quality and health risk assessment model was developed. The research findings show that the main chemical components and TDS in the groundwater have obvious spatial distribution characteristics, i.e., the content of deep karst water (DKW) in the west is significantly lower than that of shallow pore water (SPW) in the east, and the hydrochemical type has changed from HCO3–Ca to SO4–Ca. The chemical components of SPW and DKW are mainly derived from silicates and carbonates, accompanied by weathering dissolution of sulphidic minerals, especially SPW. The chemical components of the groundwater was also influenced by the cation exchange reaction and human activities. The quality of the SPW was significantly worse than that of the DKW, and the nitrates in SPW carry a high non-carcinogenic risk, especially to children. The shallow pore water is not suitable for drinking water. This study can provide guidance on the safety of drinking water in the Fengfeng coal mining area and other areas with intensive industrial, mining, and agricultural activities. Full article
(This article belongs to the Special Issue Soil-Groundwater Pollution Investigations)
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18 pages, 5242 KiB  
Article
Research on Temperature Control Index for High Concrete Dams Based on Information Entropy and Cloud Model from the View of Spatial Field
by Guang Yang, Jin Sun, Jianwei Zhang, Jingtai Niu, Bowen Luan, Zhendong Huang and Ahui Zhao
Water 2023, 15(22), 4023; https://doi.org/10.3390/w15224023 - 20 Nov 2023
Cited by 2 | Viewed by 1216
Abstract
It is significant to adopt scientific temperature control criteria for high concrete dams in the construction period according to practical experience and theoretical calculation. This work synthetically uses information entropy and a cloud model and develops novel in situ observation data-based temperature control [...] Read more.
It is significant to adopt scientific temperature control criteria for high concrete dams in the construction period according to practical experience and theoretical calculation. This work synthetically uses information entropy and a cloud model and develops novel in situ observation data-based temperature control indexes from the view of a spatial field. The order degree and the disorder degree of observation values are defined according to the probability principle. Information entropy and weight parameters are combined to describe the distribution characteristics of the temperature field. Weight parameters are optimized via projection pursuit analysis (PPA), and then temperature field entropy (TFE) is constructed. Based on the above work, multi-level temperature control indexes are set up via a cloud model. Finally, a case study is conducted to verify the performance of the proposed method. According to the calculation results, the change law of TFEs agrees with actual situations, indicating that the established TFE is reasonable, the application conditions of the cloud model are wider than those of the typical small probability method, and the determined temperature control indexes improve the safety management level of high concrete dams. Research results offer scientific reference and technical support for temperature control standards adopted at other similar projects. Full article
(This article belongs to the Special Issue Remote Sensing, Artificial Intelligence and Deep Learning in Hydraulic Structure Safety Monitoring)
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22 pages, 3689 KiB  
Article
Slope Stability Evaluation Due to Reservoir Draw-Down Using LEM and Stress-Based FEM along with Mohr–Coulomb Criteria
by Binaya Raj Pandey, Helmut Knoblauch and Gerald Zenz
Water 2023, 15(22), 4022; https://doi.org/10.3390/w15224022 - 20 Nov 2023
Cited by 1 | Viewed by 1950
Abstract
Rapid Draw-Down (RDD) in an earthfill dam has serious implications for dam safety regarding slope stability issues. The evaluation of reservoir draw-down impact on slope stability was carried out with the Limit Equilibrium Method (LEM) and stress-based Finite Element Method (FEM), using GeoStudio. [...] Read more.
Rapid Draw-Down (RDD) in an earthfill dam has serious implications for dam safety regarding slope stability issues. The evaluation of reservoir draw-down impact on slope stability was carried out with the Limit Equilibrium Method (LEM) and stress-based Finite Element Method (FEM), using GeoStudio. The time-dependent Factor of Safety (FOS) and nonlinear behavior were evaluated considering 8 h of RDD. The resulting FOS values of 1.28 and 1.27 using LEM and stress-based FEM were classified as unsafe. The minimum allowable draw-down factor of safety value is 1.3, as per the guideline. The suggested two designs, with upstream horizontal filters and increased upstream dam permeability, provided an adequate FOS. However, the nonlinear analysis with coupled FEM has shown that the upstream slope is unstable in all three cases (i.e., as-built design, increased upstream dam shell permeability, and suggested application of horizontal filter layers) considering 8 h of RDD. Several gradual draw-down rates were also tested and it has been found that the FOS increases with decreased draw-down rates. FOS charts, pressure fluctuation, and flow measurements in the upstream dam shell have revealed that slope stability is highly influenced by pore water pressure and draw-down rate. The safe allowable draw-down rate of 20 h was identified, considering the as-built design of the dam. Full article
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17 pages, 1679 KiB  
Article
Research on the Water Environment Governance of Hangzhou Bay Based on the DEA–Tobit Model
by Daizhong Tang, Tong Deng and Shanyu Lin
Water 2023, 15(22), 4021; https://doi.org/10.3390/w15224021 - 20 Nov 2023
Viewed by 1665
Abstract
With rapid urbanization and industrialization, Hangzhou Bay faces significant pressure in water environment governance. This study, based on panel data from 2011 to 2021 in Zhejiang’s Hangzhou, Jiaxing, Shaoxing, and Ningbo, employs the Super-Efficiency DEA model to assess water environment governance performance. The [...] Read more.
With rapid urbanization and industrialization, Hangzhou Bay faces significant pressure in water environment governance. This study, based on panel data from 2011 to 2021 in Zhejiang’s Hangzhou, Jiaxing, Shaoxing, and Ningbo, employs the Super-Efficiency DEA model to assess water environment governance performance. The Tobit model analyzes external environmental factors. Findings reveal fluctuating water governance efficiency during the study period, with inefficiencies from 2012 to 2019, followed by significant improvement from 2019 to 2021. Key factors impacting governance include urban water environment performance in Hangzhou, urban residents’ disposable income, population density, and secondary industry GDP development. A higher urban income enhances environmental awareness and governance performance, while population density and industrial GDP intensify resource use, energy consumption, and wastewater discharge, worsening governance pressures and performance. This research offers insights for enhancing water environment governance in Hangzhou Bay, aiding in the formulation of protection plans and management policies. Additionally, it provides valuable experiences for watershed governance globally. Full article
(This article belongs to the Special Issue Urban Water Management and Governance)
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17 pages, 5559 KiB  
Article
Evaluation of Future-Integrated Urban Water Management Using a Risk and Decision Analysis Framework: A Case Study in Denver–Colorado Metro Area (DCMA)
by Bowen He, Han Zheng and Qun Guan
Water 2023, 15(22), 4020; https://doi.org/10.3390/w15224020 - 20 Nov 2023
Cited by 4 | Viewed by 1446
Abstract
This study examines the DCMA concerning the future risk of the water security status. We considered three risk factors: population growth, economic growth, and natural water supply–demand differences. In the risk analysis part, we consulted with experts from several sectors including academia, Non-Governmental [...] Read more.
This study examines the DCMA concerning the future risk of the water security status. We considered three risk factors: population growth, economic growth, and natural water supply–demand differences. In the risk analysis part, we consulted with experts from several sectors including academia, Non-Governmental Organizations (NGOs), and industry, to predict that the probability of future water stresses in high-, medium-, and low-risk scenarios are 0.73, 0.24, and 0.03, respectively. In the decision analysis part, we adopted two multiple criteria decision analysis (MCDA) approaches that include multiple attribute value theory (MAVT) and analytic hierarchy process (AHP) methods to evaluate the best alternative decision to alleviate future water stresses in the DCMA. The sensitivity analysis demonstrates that, although expanding existing water reservation might be a solution to tackle the challenge, the best option really closely connects to the weighting scheme of the criteria considered in the framework. This study provides a valuable risk and decision analysis framework to analyze the water security status associated with the future water supply and demand gap decrease caused by three risk factors: population growth, climate change, and natural water supply. Full article
(This article belongs to the Section Urban Water Management)
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15 pages, 7295 KiB  
Article
Application of a U-Tube Oxygenator in a Litopenaeus vannamei Recirculating Aquaculture System: Efficiency and Management Models
by Jianping Xu, Yishuai Du, Guogen Su, Hexiang Wang, Jiawei Zhang, Huiqin Tian, Li Zhou, Tianlong Qiu and Jianming Sun
Water 2023, 15(22), 4019; https://doi.org/10.3390/w15224019 - 20 Nov 2023
Viewed by 1419
Abstract
This study investigated the dissolved oxygen (DO) variation pattern in a Litopenaeus vannamei recirculating aquaculture system (RAS) and established an oxygen-utilization rate (UROxygen) model, pure oxygen addition (QOxygen) model, and control model that linked a microscreen drum [...] Read more.
This study investigated the dissolved oxygen (DO) variation pattern in a Litopenaeus vannamei recirculating aquaculture system (RAS) and established an oxygen-utilization rate (UROxygen) model, pure oxygen addition (QOxygen) model, and control model that linked a microscreen drum filter (MDF) with a U-tube oxygenator. The main objective was to promote the application of the U-tube oxygenator and achieve the efficient, accurate, and automated management of DO in an RAS. To avoid wasting oxygen and ensure production safety, it was recommended to maintain the effluent of the aquaculture pond at 6.9 ± 0.4 mg/L. The modeled relationship between the RAS flow (QRAS), QOxygen, and UROxygen was UROxygen = 0.9626 × (−105.3406 + 0.9911QRAS + 10.6202QOxygen − 0.05964QRASQOxygen − 1.2628 × 10−3QRAS2 − 0.1821QOxygen2 + 6.8888 × 10−5QRAS2QOxygen + 6.3993 × 10−4QRASQOxygen2). The modeled relationship between QRAS, daily feeding rate (MFeeding), and QOxygen was QOxygen = 1.09 × (−12.8633 − 0.02793QRAS + 0.9369 MFeeding − 8.9286 × 10−4MFeedingQRAS + 5.6122 × 10−5QRAS2 − 2.3281 × 10−3MFeeding2). The modeled relationship between the MDF backwashing period (TMDF) and QOxygen was QOxygen = −11.57ln(TMDF) + 78.319. This study provided a theoretical basis and novel methods for the management of DO in an RAS, thus promoting the healthy and stable development of an L. vannamei RAS. Full article
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19 pages, 15966 KiB  
Article
Application of Judgmental Sampling Approach for the Monitoring of Groundwater Quality and Quantity Evolution in Mediterranean Catchments
by Maria Margarita Ntona, Konstantinos Chalikakis, Gianluigi Busico, Micòl Mastrocicco, Kyriaki Kalaitzidou and Nerantzis Kazakis
Water 2023, 15(22), 4018; https://doi.org/10.3390/w15224018 - 20 Nov 2023
Cited by 2 | Viewed by 2431
Abstract
Groundwater monitoring is critically important, even though it is costly and often neglected. In this study, a judgmental monitoring of groundwater offering solutions based on a cost and time-effective research approach is presented. The method was performed in three Mediterranean areas in Greece [...] Read more.
Groundwater monitoring is critically important, even though it is costly and often neglected. In this study, a judgmental monitoring of groundwater offering solutions based on a cost and time-effective research approach is presented. The method was performed in three Mediterranean areas in Greece and Italy to examine its advantages and disadvantages. As a first step, a multi-statistical analysis was practiced to assess and apportion the potential contributions of pollution sources of groundwater. Pearson correlation, principal component analysis, and factor analysis were applied to groundwater samples to characterize the evolution of hydrochemical processes. High concentrations of chlorides and nitrates highlight that salinization and the extensive use of nitrate fertilizers dominate in the coastal part of Eastern Thermaikos Gulf, the dissolution of carbonate rocks and livestock/industrial activities drive the groundwater quality status in the Upper Volturno basin, while in the Mouriki basin thermal power plant and the use of zinc fertilizers are the main factors of groundwater quality degradation. The determination of the critical sampling points was applied, considering the land use and hydrogeological and morphological characteristics of the areas. The application of the judgmental sampling approach provides reliable results regarding groundwater evolution. These results were compared to previous works and found that a non-probability sampling technique can provide the same results as a more costly method in the Mediterranean region. Thus, judgmental sampling is crucial for the optimal application of water resource management and control techniques in basins to avoid gaps in data collection. Full article
(This article belongs to the Section Hydrogeology)
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19 pages, 14579 KiB  
Article
Signal Spectrum Analysis of Sediment Water Impact of Hydraulic Turbine Based on ICEEMDAN-Wavelet Threshold Denoising Strategy
by Shufang Bai, Yun Zeng, Fang Dao, Boyi Xiao, Xiang Li and Jing Qian
Water 2023, 15(22), 4017; https://doi.org/10.3390/w15224017 - 19 Nov 2023
Cited by 2 | Viewed by 1542
Abstract
Studies show that sediment erosion is one of the main factors attributing to hydraulic turbine failure. The present paper represents an investigation into acoustic vibration signals generated by the water flow impacting the hydraulic turbine runner under three different operating conditions. Collected signals [...] Read more.
Studies show that sediment erosion is one of the main factors attributing to hydraulic turbine failure. The present paper represents an investigation into acoustic vibration signals generated by the water flow impacting the hydraulic turbine runner under three different operating conditions. Collected signals were denoised using the ICEEMDAN-wavelet threshold method, and then the spectral characteristics and sample entropy characteristics of the signals for the three operating conditions were analyzed. The results show that when clean water flows through the hydraulic turbine, the sample entropy reaches its smallest values and the dominant frequency component in the spectrogram is 59.39 Hz. When transitioning from clean water to the flood flow containing 2–4 mm sediment particles, the sample entropy is increasing and a high-frequency component higher than 59.39 Hz becomes the prominent frequency of the spectrogram. Meanwhile, the formation of high-frequency components increases with the sand-containing particle size. Based on the spectral characteristics and sample entropy characteristics of the acoustic vibration signals under different operating conditions, it can provide a reference for the sand avoidance operation of the hydraulic turbine during flood season. In addition, it provides a supplement to the existing hydraulic turbine condition’s monitoring systems and a new avenue for subsequent research on early warning of hydraulic turbine failure. Full article
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12 pages, 1140 KiB  
Article
Mechanism Analysis and Demonstration of Effective Information Extraction in the System Differential Response Inversion Estimation Method
by Yang Chen, Kexin Liu, Sijun Jiang, Yiqun Sun and Hui Chen
Water 2023, 15(22), 4016; https://doi.org/10.3390/w15224016 - 19 Nov 2023
Viewed by 1019
Abstract
The system differential response method for inverse estimation has received much attention in the hydrology literature. However, its underlying mechanisms remain largely unexplored, highlighting the need for this study. This study proposes the relation degree coefficient (RC) concept describing the nonlinear relationships between [...] Read more.
The system differential response method for inverse estimation has received much attention in the hydrology literature. However, its underlying mechanisms remain largely unexplored, highlighting the need for this study. This study proposes the relation degree coefficient (RC) concept describing the nonlinear relationships between different variables and demonstrates that the selective information extraction ability of the method was first demonstrated from a theoretical perspective. Synthetic cases were conducted to demonstrate the method performance under various variables to be estimated. The results show that the useful information is extracted from the relationship between the variables to be estimated and the observed discharge. In addition, there is a general trend that suggests that incorporating more variables into the inversion estimation can lead to enhanced estimation performance. Full article
(This article belongs to the Section Hydrology)
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20 pages, 3008 KiB  
Article
Wastewater Treatment System Optimization for Sustainable Operation of the SHARON–Anammox Process under Varying Carbon/Nitrogen Loadings
by Paulina Vilela, Kijeon Nam and Changkyoo Yoo
Water 2023, 15(22), 4015; https://doi.org/10.3390/w15224015 - 19 Nov 2023
Cited by 2 | Viewed by 1855
Abstract
Partial nitritation (PN) coupled with the anaerobic ammonium oxidation (Anammox) process has improved ammonium removal in wastewater treatment plants (WWTPs). The operation conditions of this process, i.e., the dissolved oxygen (DO) and the influent ammonium and nitrite concentrations, drive the process to an [...] Read more.
Partial nitritation (PN) coupled with the anaerobic ammonium oxidation (Anammox) process has improved ammonium removal in wastewater treatment plants (WWTPs). The operation conditions of this process, i.e., the dissolved oxygen (DO) and the influent ammonium and nitrite concentrations, drive the process to an equilibrium to suppress nitrite-oxidizing bacteria and achieve a proper nitrite over ammonium (NO2/NH4) ratio. This study aimed to implement a set of control strategies in a WWTP model BSM2-SHAMX, combining PN in a single reactor system for high-activity ammonia removal over nitrite (SHARON) to an Anammox reactor, using proportional–integrative–derivative (PID) control and model predictive control (MPC) in a cascade. For correct coupling, the PN should maintain an output NO2/NH4 ratio between 1 and 1.3, suitable for the Anammox process. In the cascade controller feedback loop, the primary control loop controls the NO2/NH4 ratio through the DO concentration from the secondary control loop, which guarantees better effluent nitrogen removal. The performance of the plant was assessed by evaluating the control strategies with different influent carbon/nitrogen (C/N) loadings. The study results showed that the MPC controllers provided better results, with an improvement of 36% in the operational cost compared to the base case with a cost around 26,000 EUR/d, and better nitrogen removal surpassing 90% removal, 10% more than the base case. Full article
(This article belongs to the Special Issue Recent Advances in Green Water Systems and Digital Twin)
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14 pages, 5203 KiB  
Article
Effect of Aeration on the Cavitation Characteristics of the Control Valve in Hydro-Driven Ship Lifts
by Jiao Wang, Yaan Hu, Liang Chen, Ruichang Hu and Hao Yuan
Water 2023, 15(22), 4014; https://doi.org/10.3390/w15224014 - 19 Nov 2023
Cited by 2 | Viewed by 1573
Abstract
In hydro-driven ship lifts, plunger valves and fixed cone valves are the most suitable structures for achieving accurate flow control under a wide range of flow conditions. In order to inhibit cavitation in these valve structures, experiments were conducted in which forced aeration [...] Read more.
In hydro-driven ship lifts, plunger valves and fixed cone valves are the most suitable structures for achieving accurate flow control under a wide range of flow conditions. In order to inhibit cavitation in these valve structures, experiments were conducted in which forced aeration was applied before the valve. The cavitation phenomena and aerated flow regime were observed through a transparent glass pipe, and the cavitation noise characteristics were recorded using a hydrophone. The test results show that aeration can reduce the valve working cavitation number, albeit to a limited degree (<5%). Based on the sound velocity theory of aerated flow and the experimental results, the relationship between the aeration concentration and the cavitation inhibition efficiency was obtained. When the aeration concentration is approximately 0.1%, cavitation can be significantly inhibited via forced aeration before the valve. Once the aeration concentration reaches 0.9%, the cavitation inhibition efficiency becomes saturated. The research results presented in this paper provide a reference for the cavitation inhibition of industrial valves. Full article
(This article belongs to the Special Issue Hydro-Sediment Dynamics in Vegetated Rivers)
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14 pages, 3258 KiB  
Article
Effective Adsorption of Chlorinated Polyfluoroalkyl Ether Sulfonates from Wastewater by Nano-Activated Carbon: Performance and Mechanisms
by Hao Yi, Xiaolin Chen, Zewei Liu, Hongxia Xi, Zecong Ding, Kai Cui and Yongyou Hu
Water 2023, 15(22), 4013; https://doi.org/10.3390/w15224013 - 19 Nov 2023
Viewed by 1273
Abstract
Chlorinated polyfluoroalkyl ether sulfonates (F-53B) were often used as mist suppressants in the chrome plating industry, resulting in the large discharge of F-53B-containing electroplating wastewater into the aquatic environment. Due to the high toxicity of F-53B, increasing attention has been paid to its [...] Read more.
Chlorinated polyfluoroalkyl ether sulfonates (F-53B) were often used as mist suppressants in the chrome plating industry, resulting in the large discharge of F-53B-containing electroplating wastewater into the aquatic environment. Due to the high toxicity of F-53B, increasing attention has been paid to its efficient removal from wastewater. In this study, three nano-activated carbons were successfully prepared from coconut shell carbons by a simple one-step KOH activation method. The nitrogen adsorption/desorption experiments showed that the synthesized coconut shell activated carbons possessed a well-developed nano-pore structure, which was favorable for the adsorption of F-53B. The results suggested that the adsorption of F-53B on the coconut shell activated carbons followed pseudo-second-order kinetics and was better fitted in the Langmuir isotherm, indicating that the adsorption of F-53B was mainly controlled by chemical adsorption and was mainly monolayer adsorption. Theoretical calculation results revealed that the faster adsorption rate of F-53B on CSAC_800 than on CSAC_600 and CSAC_700 could be contributed to the lower adsorption energy of F-53B on CSAC_800 and the higher self-diffusion coefficients of F-53B in CSAC_800. The higher adsorption capacity of CSAC_800 (qm = 537.6 mg·g−1) for F-53B than that of CSAC_600 (qm = 396.83 mg·g−1) and CSAC_700 (qm = 476.19 mg·g−1) could be attributed to the higher specific surface area and larger number of adsorption sites of CSAC_800. The results of this study demonstrate that coconut shell activated carbons with a well-developed nano-pore structure are an effective adsorbent for F-53B removal and have a good application prospect. Full article
(This article belongs to the Special Issue Nanoparticles for Environmental Risk Reduction in Water and Wastewater)
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16 pages, 1646 KiB  
Article
Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for Cryptosporidium Oocyst Removal
by Álef Luan de Souza Pereira, Cristina Celia Silveira Brandão, Yovanka Pérez Ginoris and Carla Patrícia Pereira Alves
Water 2023, 15(22), 4012; https://doi.org/10.3390/w15224012 - 19 Nov 2023
Viewed by 1437
Abstract
Monitoring the removal of Cryptosporidium oocysts in water treatment plants is a challenge, particularly in developing countries, and the use of surrogates has proven necessary. Two surrogates already investigated and recognized by the scientific community are aerobic spore-forming bacteria (ASFB) and fluorescent polystyrene [...] Read more.
Monitoring the removal of Cryptosporidium oocysts in water treatment plants is a challenge, particularly in developing countries, and the use of surrogates has proven necessary. Two surrogates already investigated and recognized by the scientific community are aerobic spore-forming bacteria (ASFB) and fluorescent polystyrene microspheres (ME). In this context, this study evaluates and compares the performance of upflow direct filtration and downflow direct filtration, with emphasis on the removal of ASFB and ME as a surrogate of Cryptosporidium oocyst removal. Pilot filtration experiments were carried out with low turbidity Paranoá Lake water (average—3.7 NTU) with ASFB varying from 7 × 102 to 5.5 × 103 CFU/100 mL. In some experiments, water was spiked with microspheres, aiming for 105 ME/L. Two operational conditions were evaluated: (1) filters operating with the same filtration rate (5 m/h); (2) filters operating with the same flow rate of 59.41 L/h. In general, the downflow filter presented a slightly higher removal efficiency than the upflow filter but the differences were not considered statistically significant in most cases. The removal efficiency of microspheres (3 to 5 log) was higher than that of ASFB (1.2 to 4 log) in both filters, corroborating that the removal of ASFB is a conservative surrogate of the removal of Cryptosporidium. Full article
(This article belongs to the Special Issue Water Quality and Purification)
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20 pages, 3588 KiB  
Article
Sedimentation Characteristics of the Fluctuating Backwater Area at the Tail of Cascade Reservoirs: A Case Study of the Three Gorges Reservoir
by Jun Li, Hua Ge, Yanrong Ping, Xianyong Dong, Lingling Zhu and Yaochang Ma
Water 2023, 15(22), 4011; https://doi.org/10.3390/w15224011 - 19 Nov 2023
Viewed by 1234
Abstract
The construction of cascade reservoirs is associated with considerable uncertainty in sedimentation in the fluctuating backwater area of the terminal reservoir and poses challenges to water safety. The sedimentation characteristics under the influence of multiple factors in the main urban area of the [...] Read more.
The construction of cascade reservoirs is associated with considerable uncertainty in sedimentation in the fluctuating backwater area of the terminal reservoir and poses challenges to water safety. The sedimentation characteristics under the influence of multiple factors in the main urban area of the Chongqing river section were analyzed as a case study for the operation of cascade reservoirs in the Jinsha River via the utilization of a large dataset spanning back to the normal storage of the Three Gorges Reservoir. The results of this study indicate that, owing to factors such as upstream water, sediment inflow, reservoir operation, and river sand mining, this river section experienced deposition on the sand bars and erosion in the main channel. The rate of sedimentation increased with sediment inflow, peak flow rate, and duration, while the location of sedimentation shifted as the concentration ratio changed. These results may provide technical support not only for the operation of the Three Gorges Reservoir, but also for the governance of the fluctuating backwater areas of other cascade reservoirs. Full article
(This article belongs to the Special Issue Reservoir Control Operation and Water Resources Management)
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18 pages, 4859 KiB  
Article
Runoff Decline Is Dominated by Human Activities
by Ping Miao, Dagula, Xiaojie Li, Shahid Naeem, Amit Kumar, Hongli Ma, Yenong Ding, Ruidong Wang and Jinkai Luan
Water 2023, 15(22), 4010; https://doi.org/10.3390/w15224010 - 18 Nov 2023
Viewed by 1828
Abstract
Investigations into runoff change and its influencing factors hold immense significance for promoting sustainable development, efficient water resource utilization, and the improvement of the ecological environment. To reduce methodological uncertainties, this study employed six attribution analysis methods, including two statistical approaches, a Budyko [...] Read more.
Investigations into runoff change and its influencing factors hold immense significance for promoting sustainable development, efficient water resource utilization, and the improvement of the ecological environment. To reduce methodological uncertainties, this study employed six attribution analysis methods, including two statistical approaches, a Budyko equation sensitivity coefficient method, and three hydrology models, to differentiate the contributions of climate change and human activities to the runoff change in the Xiliugou basin. The results indicated an abrupt change point in 2006, and the annual runoff series from 1960 to 2020 demonstrated a significant declining trend. All the six methods revealed that human activities were the major influencing factor. The average contribution rate of climate change was noted to be 24.2%, while that of human activities was 75.8% among the six methods used for this study. The prominent human activities in the Xiliugou basin revolve around soil and water conservation measures. The research findings hold great significance for the comprehensive understanding of runoff formation and its response to the changing environment in the Xiliugou basin. Additionally, these results can provide a foundation for decision-making for water resource management and ecological protection. Full article
(This article belongs to the Special Issue Impact of Climate and Socio-Economic on Irrigation Water Management and Agricultural Water Productivity)
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18 pages, 4925 KiB  
Article
Study on the Optimization of Multi-Objective Water Resources Allocation in the Henan Yellow River Water Supply Zone
by Yanbin Li, Ke Sun, Ruyi Men, Fei Wang, Daoxi Li, Yuhang Han and Yanping Qu
Water 2023, 15(22), 4009; https://doi.org/10.3390/w15224009 - 18 Nov 2023
Cited by 3 | Viewed by 1582
Abstract
With the continuous growth in the global population, rapid socioeconomic development, and the impacts of factors like climate change, we are facing increasingly severe challenges regarding water scarcity. The scientific and rational allocation of water resources has become a key factor in ensuring [...] Read more.
With the continuous growth in the global population, rapid socioeconomic development, and the impacts of factors like climate change, we are facing increasingly severe challenges regarding water scarcity. The scientific and rational allocation of water resources has become a key factor in ensuring sustainable development. The Henan Yellow River water supply zone occupies a crucial position in the socioeconomic development of Henan Province. Currently, there is a shortage of water resources with relatively low utilization rates. To alleviate the contradiction between water supply and demand, a study on the optimization of water resources (with p = 90%) for the years 2025 and 2030 was conducted. In this study, we constructed a multi-objective optimization model with the objectives of maximizing economic benefits, minimizing total water shortage, and maximizing water use efficiency. The second-generation non-dominated sorting genetic algorithm (NSGA-II) was utilized to solve this model. The results indicate that by 2025, the optimized allocation of water resources will correspond to 17.663 billion m3, reducing the average water shortage rate in the research area to 9.69%. By 2030, the optimized allocation of water resources will further increase to 18.363 billion m3, bringing down the average water shortage rate to 8.34%. Concurrently, the supply structure of the research area will significantly improve after optimization. This is manifested through an increase in the proportion of surface water supply and a substantial rise in the proportion of supply from other water sources, while the proportion of groundwater supply noticeably decreases. These research findings can serve as a reference for the rational utilization and distribution of water resources in the future and can also offer insights for optimizing water resource allocation in other regions. Full article
(This article belongs to the Special Issue Impacts of Climate Change on Water Resources and Water Risks, the 2nd Edition)
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12 pages, 2092 KiB  
Article
Feasibility Study of Using Excess Sludge Fermentation Broth as a Co-Metabolic Carbon Source for 2,4,6-Trichlorophenol Degradation
by Jianguang Wang, Zhirong Sun and Jun Li
Water 2023, 15(22), 4008; https://doi.org/10.3390/w15224008 - 18 Nov 2023
Cited by 1 | Viewed by 1501
Abstract
Excess sludge fermentation is a commonly employed method for carbon sources in wastewater treatment plants, but its use as a carbon source for chlorophenol removal has been relatively underexplored. In this study, a laboratory-scale sludge fermentation SBR (FSBR) was integrated with a 2,4,6-trichlorophenol [...] Read more.
Excess sludge fermentation is a commonly employed method for carbon sources in wastewater treatment plants, but its use as a carbon source for chlorophenol removal has been relatively underexplored. In this study, a laboratory-scale sludge fermentation SBR (FSBR) was integrated with a 2,4,6-trichlorophenol (2,4,6-TCP) degradation SBR (DSBR), resulting in a stable removal of 2,4,6-TCP without the need for external carbon sources. In this coupled system, the concentrations of volatile fatty acids in FSBR remained constant, with acetic acid, propionic acid, butyric acid, and valeric acid concentrations reaching 322.04 mg COD/L, 225.98 mg COD/L, 274.76 mg COD/L, and 149.58 mg COD/L, respectively, and the acid production efficiency increased to 88.40%. Throughout the 110-day operational period, the activated sludge concentration in the DSBR was consistently maintained at 3021 ± 110 mg/L, and the sludge SVI remained stable at 70 mL/g. The maximum amount of 2,4,6-TCP removed reached 240.13 mg/L within a 12 h operating cycle. The use of excess sludge fermentation can completely replace commercial carbon sources for 2,4,6-TCP removal, leading to cost savings in chlorophenol treatment and broadening the applicability of this technology. Full article
(This article belongs to the Special Issue Occurrence, Risk Assessment and Removal of Emerging Contaminants in Aquatic Environment)
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48 pages, 4804 KiB  
Article
Watershed Development and Eutrophying Potable Source-Water Reservoirs in a Warming Temperate/Subtropical Region
by JoAnn M. Burkholder, Carol A. Kinder and Elle H. Allen
Water 2023, 15(22), 4007; https://doi.org/10.3390/w15224007 - 17 Nov 2023
Viewed by 1560
Abstract
Reservoirs are increasingly valuable worldwide as potable source waters, yet in many geographic regions, their limnology and trophic status are poorly known. We characterized 14 drinking water reservoirs and their watersheds across the warming temperate/subtropical southeastern USA. Selected reservoirs had at least three [...] Read more.
Reservoirs are increasingly valuable worldwide as potable source waters, yet in many geographic regions, their limnology and trophic status are poorly known. We characterized 14 drinking water reservoirs and their watersheds across the warming temperate/subtropical southeastern USA. Selected reservoirs had at least three years of accessible summer water quality data during 2010–2020, including Secchi depth, nutrients, and algal biomass as chlorophyll a, and depth profiles for temperature and dissolved oxygen. Most watersheds, including lands within a 10-km radius of the reservoirs, had sustained substantial urbanization and/or intensive industrialized animal production, in some cases including the discharge of partially treated human sewage or livestock slaughterhouse wastes near or into the reservoirs. Five reservoirs were assessed as mesotrophic; the others were eutrophic. Most were stratified, but ephemeral near-surface thermoclines were common, and many were too shallow (median depth 5.0 m) to maintain uniform temperatures in the relatively warm hypolimnia. Bottom-water hypoxia/anoxia occurred throughout the summers but, surprisingly, in 8 of 14 reservoirs hypoxia commonly extended to surface waters. In the Southeast as in many regions, drinking water reservoirs are poorly protected and degrading as livestock production and/or urban development increasingly characterize their watersheds. The eutrophication trajectory of these valuable resources should be used as an indicator of ecosystem health and water quality in developing more protective management and policy actions. Full article
(This article belongs to the Special Issue Eutrophication and Harmful Algae in Aquatic Ecosystems)
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17 pages, 6079 KiB  
Article
Using Activated Biochar from Caryocar brasiliense Pequi Almonds for Removing Methylene Blue Dye in an Aqueous Solution
by André Luiz Ferreira Carvalho Melo, Marcelo Teixeira Carneiro, Alan Ícaro Sousa Morais, Bartolomeu Cruz Viana, Francisco Eroni Paz Santos, Josy Anteveli Osajima, Roosevelt D. S. Bezerra, Ramón Raudel Peña-Garcia, Luciano C. Almeida, Santiago Medina Carrasco and Edson C. Silva-Filho
Water 2023, 15(22), 4006; https://doi.org/10.3390/w15224006 - 17 Nov 2023
Cited by 1 | Viewed by 1528
Abstract
Water pollution remains a global problem that urges researchers to develop new technologies aimed at environmental restoration. Here, this study aimed at obtaining an activated biochar from pequi almonds for dye removal. Before and after adsorption, the materials underwent characterization using techniques such [...] Read more.
Water pollution remains a global problem that urges researchers to develop new technologies aimed at environmental restoration. Here, this study aimed at obtaining an activated biochar from pequi almonds for dye removal. Before and after adsorption, the materials underwent characterization using techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Raman spectroscopy, and thermogravimetric analysis (TG). The biochar from the pequi almond was called BA, and the activated biochar from the pequi almond was called ABA. The influence of the pH, contact time, and adsorbate concentration on adsorption was investigated using the dye methylene blue. The morphological assessment revealed higher cracks and pores in the ABA than in the BA. The TG showed that the BA lost approximately 19% more mass than the ABA, indicating that activation occurred. The activation contributed to the decrease in the degree of disorder in the BA because of the increased number of graphitic carbon atoms (ordered) in the ABA, as observed via Raman. The adsorption kinetics followed a pseudo-second-order model, while the adsorption isotherms followed the Langmuir model. The BA adsorption capacity was 500.00 mg g−1, constituting a robust solution for dye removal from aqueous environments. Therefore, this implies the success of the process. Full article
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19 pages, 490 KiB  
Review
Adsorption Technologies for the Removal of Cytostatics in Water: A Review
by Alicia L. Garcia-Costa, Teresa I. A. Gouveia, Arminda Alves and Mónica S. F. Santos
Water 2023, 15(22), 4005; https://doi.org/10.3390/w15224005 - 17 Nov 2023
Cited by 2 | Viewed by 1389
Abstract
One of the most common treatments for cancer disease requires the administration of cytostatics, which are very effective drugs in the elimination of cancerous cells, but are toxic for healthy tissues. After being administered to patients, they are excreted and frequently reach natural [...] Read more.
One of the most common treatments for cancer disease requires the administration of cytostatics, which are very effective drugs in the elimination of cancerous cells, but are toxic for healthy tissues. After being administered to patients, they are excreted and frequently reach natural water bodies, due to their poor degradation in wastewater treatment plants (WWTPs), posing a global threat to the environment and human health. The study of proper treatment approaches for the effective removal of these hazardous drugs in WWTPs is thus a topic of concern and of utmost importance to ensure environmental integrity, resilience and sustainability. The aim of this work is to perform a comprehensive review of the application of adsorption-based processes for the treatment of aqueous matrices contaminated with cytostatics, which has never been addressed before. A detailed discussion on the operating conditions, type and concentrations of sorbents used, toxicity of the effluents and other relevant parameters is presented. This paper aims to help identify the most promising sorbents and conditions, the current knowledge gaps, and future challenges/perspectives on adsorption technologies (isolated or coupled with other processes) to tackle the problem of cytostatic fingerprints in water courses. Additionally, information concerning the implementation of these technologies from an environmental and economic (life cycle assessment) perspective is given. Full article
(This article belongs to the Special Issue Occurrence of Pharmaceuticals in Water and Their Removal Technologies)
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11 pages, 233 KiB  
Editorial
New Advances in Water Hammer Problems
by Kamil Urbanowicz and Helena Margarida Ramos
Water 2023, 15(22), 4004; https://doi.org/10.3390/w15224004 - 17 Nov 2023
Cited by 1 | Viewed by 2638
Abstract
When the flow within pressurized pipes experiences abrupt stoppages, initiation, or directional alteration, it gives rise to the phenomenon of water hammer, characterized by the propagation of waves [...] Full article
(This article belongs to the Special Issue About an Important Phenomenon—Water Hammer)
22 pages, 4316 KiB  
Article
Simulating Potential Impacts of Solar MajiPump on the Economy and Nutrition of Smallholder Farmers in Sub-Humid Ethiopia
by Jean-Claude Bizimana, Belainew B. Yalew, Tewodros T. Assefa, Sisay A. Belay, Yonas M. Degu, Tafadzwanashe Mabhaudhi, Manuel R. Reyes, P. V. Vara Prasad and Seifu A. Tilahun
Water 2023, 15(22), 4003; https://doi.org/10.3390/w15224003 - 17 Nov 2023
Cited by 1 | Viewed by 1671
Abstract
Irrigation is widely considered a potential means to improve agricultural productivity, nutrition, and income, as farmers can carry out farming and production year-round. However, the feasibility of irrigation technologies is highly dependent on the long-term economic return farmers achieve. Solar-based irrigation could address [...] Read more.
Irrigation is widely considered a potential means to improve agricultural productivity, nutrition, and income, as farmers can carry out farming and production year-round. However, the feasibility of irrigation technologies is highly dependent on the long-term economic return farmers achieve. Solar-based irrigation could address the challenges of underinvestment in irrigation within Africa. Evidence on the economic viability of the adopted solar pumps such as MajiPump is very scant and focused on ex post evaluation. This study evaluated the income and nutritional feasibility of solar-powered irrigation using the MajiPump in sub-humid Ethiopian highlands using the farm simulation (FARMSIM) model and compared it with the manual pulley system. Results from the FARMSIM model show that farmers’ adoption of Maji solar pump technology to grow vegetables is economically feasible with financial support such as credit or loan for initial and capital investment to acquire the pump. The average profit under the solar MajiPump, drip irrigation, and conservation agriculture was 3.6 times higher than that of the baseline scenario. While the pulley technology provides the same amount of irrigation water to grow vegetables, its feasibility is limited due to high labor costs and time, estimated to be more than seven times the baseline. The simulation results show that the alternative scenarios’ nutrition level has improved relative to other scenarios and met the minimum daily average nutrition requirement level for proteins, iron, and vitamin A but fell short in fat, calcium, and calories. The results suggest that farmers who adopt improved small-scale irrigation technologies (solar MajiPump and drip system) have a higher potential to increase production and income from irrigated crops and improve their nutrition if part of the income generated is used to purchase supplemental food for their nutrition. Full article
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14 pages, 11723 KiB  
Article
Changes in the Urban Hydrological Cycle of the Future Using Low-Impact Development Based on Shared Socioeconomic Pathway Scenarios
by Eui Hyeok Yoon, Jang Hyun Sung, Byung-Sik Kim, Kee-Won Seong, Jung-Ryel Choi and Young-Ho Seo
Water 2023, 15(22), 4002; https://doi.org/10.3390/w15224002 - 17 Nov 2023
Cited by 2 | Viewed by 1513
Abstract
Representative Concentration Pathway (RCP) scenarios have been used for various studies in the field of climate change. In this regard, the Shared Socioeconomic Pathway (SSP) scenario has been newly introduced to examine climate change impacts, but relevant research is still insufficient. For this [...] Read more.
Representative Concentration Pathway (RCP) scenarios have been used for various studies in the field of climate change. In this regard, the Shared Socioeconomic Pathway (SSP) scenario has been newly introduced to examine climate change impacts, but relevant research is still insufficient. For this reason, new SSP scenarios with a combination of Low-Impact Development (LID) techniques are applied to predict rainfall-runoff efficiency and hydrological variation. The inter-model variability in the monthly average precipitation for each GCM according to new SSP scenarios under future climate was investigated. Based on the RCP 4.5 and RCP 8.5 scenarios, the results show precipitation changes with an increase of 4.8% and 12.3%, respectively. Furthermore, precipitation projections under SSP2-4.5 and SSP5-8.5 scenarios are predicted to increase by 13.9% and 20.6%, respectively, indicating that the magnitude of precipitation increases with new climate change scenarios. The Storm Water Management Model (SWMM) during the future period indicated that LID applications will reduce runoff compared with scenarios with no LID application. In particular, the introduction of permeable pavement and infiltration trenches revealed the best runoff reduction performance among the combinations of LID techniques considered. In addition, this study projected changes in the urban hydrological cycle for the climate over the next 30 years to reflect the implementation of urban hydrological cycle plans, which take approximately 10 years. Overall, it was found that, in the future, LID applications will contribute to improving the sustainability of the urban hydrological cycle of the study area. The results of our study can provide future directions for water management strategies in Korea. Full article
(This article belongs to the Special Issue Climate Change Impacts on Land Surface, Hydrological Processes and Water Management)
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