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Water, Volume 14, Issue 1 (January-1 2022) – 133 articles

Cover Story (view full-size image): A fundamental prerequisite for the development of a reliable early warning system is the availability of accurate forecasts. In this work, we applied the WRF-ERDS workflow to the heavy rainfall event that affected the city of Palermo (Italy). The results highlight that improvement in the quantitative precipitation scenario forecast skills, supported by the adoption of the H2020 LEXIS Project computing facilities and by the assimilation of in situ observations, allowed the ERDS system to improve the prediction of peak rainfall depth. View this paper
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20 pages, 54999 KiB  
Article
Isotopic Assessment of Groundwater Salinity: A Case Study of the Southwest (SW) Region of Punjab, India
by Gopal Krishan, Mavidanam Someshwar Rao, Rajesh Vashisht, Anju Chaudhary, Jaswant Singh and Amit Kumar
Water 2022, 14(1), 133; https://doi.org/10.3390/w14010133 - 05 Jan 2022
Cited by 15 | Viewed by 5364
Abstract
In recent decades, due to rapid increases in water demand and greater usage of water for irrigation from surface canals, waterlogging problems have been created in the southwest zone of Punjab, coupled with a stagnation in saline zone formation due to salinity ingression. [...] Read more.
In recent decades, due to rapid increases in water demand and greater usage of water for irrigation from surface canals, waterlogging problems have been created in the southwest zone of Punjab, coupled with a stagnation in saline zone formation due to salinity ingression. To understand these salinity issues, the present study has been conducted in three districts (Muktsar, Fazilka, and Faridkot) of Punjab to understand the root cause. To this end, groundwater samples were collected from 142 piezometers developed at 40 sites. Electrical conductivity (EC) observations were taken in the field, and collected samples were analyzed for isotopes in the laboratory. Results found that salinity in groundwater arises from the combination of evaporation enrichment and salt dissolution. The dissolved salts may be acquired due to salts from aquifer materials or salts from surface soils dissolving and leaching down with the recharging water. Besides, the zone of interaction is mapped using stable isotopic composition. The study suggests that zone of interaction between aquifers can be effectively used in groundwater augmentation, management, and contamination control at regional and/or global scales to curb water demand in the future. Full article
(This article belongs to the Topic Organic Pollution in Soil and Groundwater)
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21 pages, 43748 KiB  
Article
Hydrochemical Characteristics of Earthquake-Related Thermal Springs along the Weixi–Qiaohou Fault, Southeast Tibet Plateau
by Huiling Zhou, Xiaocheng Zhou, Hejun Su, Ying Li, Fengli Liu, Shupei Ouyang, Yucong Yan and Ronglong Bai
Water 2022, 14(1), 132; https://doi.org/10.3390/w14010132 - 05 Jan 2022
Cited by 9 | Viewed by 3226
Abstract
The Weixi–Qiaohou Fault (WQF) is considered an important zone of the western boundary of the Sichuan–Yunnan block, and its seismicity has attracted much attention after a series of moderate–strong earthquakes, especially the Yangbi Ms6.4 earthquake that occurred on 21 May 2021. In [...] Read more.
The Weixi–Qiaohou Fault (WQF) is considered an important zone of the western boundary of the Sichuan–Yunnan block, and its seismicity has attracted much attention after a series of moderate–strong earthquakes, especially the Yangbi Ms6.4 earthquake that occurred on 21 May 2021. In the present research, we investigate major and trace elements, as well as hydrogen and oxygen isotopes, of 10 hot springs sites located along the WQF, which are recharged by infiltrated precipitation from 1.9 to 3.1 km. The hydrochemical types of most analyzed geothermal waters are HCO3SO4-Na, SO4Cl-NaCa, and SO4-Ca, proving that they are composed of immature water and thus are characterized by weak water–rock reactions. The heat storage temperature range was from 44.1 °C to 101.1 °C; the circulation depth was estimated to range between 1.4 and 4.3 km. The results of annual data analysis showed that Na+, Cl, and SO42− in hot springs decreased by 11.20% to 23.80% north of the Yangbi Ms5.1 earthquake, which occurred on 27 March 2017, but increased by 5.0% to 28.45% to the south; this might be correlated with the difference in seismicity within the fault zone. The results of continuous measurements of NJ (H1) and EYXX (H2) showed irregular variation anomalies 20 days before the Yangbi Ms6.4 earthquake. In addition, Cl concentration is more sensitive to near-field seismicity with respect to Na+ and SO42−. We finally obtained a conceptual model on the origin of groundwater and the hydrogeochemical cycling process in the WQF. The results suggest that anomalies in the water chemistry of hot spring water can be used as a valid indicator of earthquake precursors. Full article
(This article belongs to the Special Issue Earthquakes and Groundwater)
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19 pages, 8053 KiB  
Article
Estimation of Groundwater Depletion in Iran’s Catchments Using Well Data
by Zohreh Safdari, Hossein Nahavandchi and Gholamreza Joodaki
Water 2022, 14(1), 131; https://doi.org/10.3390/w14010131 - 05 Jan 2022
Cited by 6 | Viewed by 3454
Abstract
Iran is experiencing significant water challenges that have now turned water security into a national priority. By estimating secular trend groundwater storage in Iran between 2002 and 2017, we see that there is an intensive negative trend, even −4400 Mm3 in some [...] Read more.
Iran is experiencing significant water challenges that have now turned water security into a national priority. By estimating secular trend groundwater storage in Iran between 2002 and 2017, we see that there is an intensive negative trend, even −4400 Mm3 in some areas. These estimations show shifting in the climate and extra extraction from aquifers for agricultural use in some areas in Iran. The secular trend of groundwater storage changes across the whole of Iran inferred from observation well data is −20.08 GT/yr. The secular trends of GWS changes based on observation well data are: −11.55 GT/yr for the Central Plateau basin, −3.60 GT/yr for the Caspian Sea basin, −3.0 GT/yr for the Persian Gulf and Oman Sea basin, −0.53 GT/yr for the Urmieh Lake basin, −0.57 GT/yr for the Eastern Boundary basin, and −0.83 GT/yr for the Gharaghom basin. The most depleted sub-basin (Kavir Markazi) has secular trends of GWS changes of −4.503 GT/yr. This study suggests that groundwater depletion is the largest single contributor to the observed negative trend of groundwater storage changes in Iran, the majority of which occurred after the drought in 2007. The groundwater loss that has been accrued during the study period is particularly alarming for Iran, which is already facing severe water scarcity. Full article
(This article belongs to the Topic Water Management in the Era of Climatic Change)
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31 pages, 57272 KiB  
Article
Statistical and Hydrological Evaluations of Water Dynamics in the Lower Sai Gon-Dong Nai River, Vietnam
by Ngo Ngoc Hoang Giang, Chau Nguyen Xuan Quang, Do Tan Long, Pham Dinh Ky, Nguyen Duc Vu and Dung Duc Tran
Water 2022, 14(1), 130; https://doi.org/10.3390/w14010130 - 05 Jan 2022
Cited by 2 | Viewed by 3926
Abstract
The water levels downstream of the Sai Gon and Dong Nai river in Southern Vietnam have been significantly changed over the last three decades, leading to severe impacts on urban flooding and salinity intrusion and threating the socio-economic development of the region and [...] Read more.
The water levels downstream of the Sai Gon and Dong Nai river in Southern Vietnam have been significantly changed over the last three decades, leading to severe impacts on urban flooding and salinity intrusion and threating the socio-economic development of the region and lives of many local people. In this study, the Mann-Kendall (MK) and trend-free prewhitening (TFPW) tests were applied to detect the water level trends and changepoints based on a water level time series at six gauging stations that were located along the main rivers to the sea over 1980–2019. The results indicated that the water level has rapidly increased by about 0.17 to 1.8 cm/year at most gauge stations surrounding Ho Chi Minh City, strongly relating to urbanization and the dike polder system’s impacts that eliminates the water storage space. In addition, the operation of upstream reservoirs has contributed to water level changes with significant consequences since the high-water level at Tri An station on the Dong Nai river occurs 1000–1500 times compared to 300–500 times before the operation. Although the effects of the flows from the sea are less than the two other factors, the local government should seriously consider water level changes, especially in the coastal regions. Our study contributes empirical evidence to evaluate the water level trends in the planning and development of infrastructure, which is necessary to adapt to future changes in Southern Vietnam’s hydrologic system. Full article
(This article belongs to the Special Issue Building Water Resilience to Achieve SDGs)
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23 pages, 4700 KiB  
Article
Priority Pollutants Monitoring and Water Quality Assessment in the Siret River Basin, Romania
by Roxana Zait, Brindusa Sluser, Daniela Fighir, Oana Plavan and Carmen Teodosiu
Water 2022, 14(1), 129; https://doi.org/10.3390/w14010129 - 05 Jan 2022
Cited by 8 | Viewed by 2903
Abstract
The Integrated Water Resources Management regulations aim to ensure a good status of surface water quality and its sustainable use. Water quality monitoring of various water users supports the identification of pollution sources and their environmental impacts. The priority pollutants generated by wastewater [...] Read more.
The Integrated Water Resources Management regulations aim to ensure a good status of surface water quality and its sustainable use. Water quality monitoring of various water users supports the identification of pollution sources and their environmental impacts. The priority pollutants generated by wastewater discharges from municipal, industrial wastewater treatment plants or agricultural areas are of great interest due to their eco-toxicological effects and bio-accumulative properties. The aim of this study was to monitor the priority organic and inorganic pollutants from the Siret River basin, in Romania, with the purpose of assessing the surface water quality status and evaluating it by the Water Quality Index (WAWQI) method. The monitoring of inorganic priority pollutants (e.g., As, Cd, Hg, Ni, Pb) and organic priority pollutants (e.g., Naphthalene, Anthracene, Phenanthrene, Fluoranthene, Benzo(a)anthracene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Benzo(ghi)perylene, Indeno(1,2,3-cd)pyrene, α, β, and γ-Hexachlorocyclohexane, and Di-2-ethyl-hexyl-phthalate) was conducted within the Siret River basin, during the period 2015–2020. With this purpose, 21 sampling points (18 river sections and 3 lakes) were considered to assess the water quality. The results of this study proved that the water quality within the Siret River basin is generally classified in the 2nd or 3rd class. The spatial distribution of the water quality index values, using ARCGIS, also highlighted the fact that the water quality is mostly unsuitable for drinking water supplies, being influenced by the quality of its main tributaries, as well as by the effluent of wastewater treatment plants. Full article
(This article belongs to the Section Water Quality and Contamination)
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15 pages, 4244 KiB  
Article
Water Turbidity Retrieval Based on UAV Hyperspectral Remote Sensing
by Mengying Cui, Yonghua Sun, Chen Huang and Mengjun Li
Water 2022, 14(1), 128; https://doi.org/10.3390/w14010128 - 05 Jan 2022
Cited by 23 | Viewed by 3797
Abstract
The water components affecting turbidity are complex and changeable, and the spectral response mechanism of each water quality parameter is different. Therefore, this study mainly aimed at the turbidity monitoring by unmanned aerial vehicle (UAV) hyperspectral technology, and establishes a set of turbidity [...] Read more.
The water components affecting turbidity are complex and changeable, and the spectral response mechanism of each water quality parameter is different. Therefore, this study mainly aimed at the turbidity monitoring by unmanned aerial vehicle (UAV) hyperspectral technology, and establishes a set of turbidity retrieval models through the artificial control experiment, and verifies the model’s accuracy through UAV flight and water sample data in the same period. The results of this experiment can also be extended to different inland waters for turbidity retrieval. Retrieval of turbidity values of small inland water bodies can provide support for the study of the degree of water pollution. We collected the images and data of aquaculture ponds and irrigation ditches in Dawa District, Panjin City, Liaoning Province. Twenty-nine standard turbidity solutions with different concentration gradients (concentration from 0 to 360 NTU—the abbreviation of Nephelometric Turbidity Unit, which stands for scattered turbidity.) were established through manual control and we simultaneously collected hyperspectral data from the spectral values of standard solutions. The sensitive band to turbidity was obtained after analyzing the spectral information. We established four kinds of retrieval, including the single band, band ratio, normalized ratio, and the partial least squares (PLS) models. We selected the two models with the highest R2 for accuracy verification. The band ratio model and PLS model had the highest accuracy, and R2 was, respectively, 0.65 and 0.72. The hyperspectral image data obtained by UAV were combined with the PLS model, which had the highest R2 to estimate the spatial distribution of water turbidity. The turbidity of the water areas in the study area was 5–300 NTU, and most of which are 5–80 NTU. It shows that the PLS models can retrieve the turbidity with high accuracy of aquaculture ponds, irrigation canals, and reservoirs in Dawa District of Panjin City, Liaoning Province. The experimental results are consistent with the conclusions of the field investigation. Full article
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13 pages, 7369 KiB  
Article
Optimization of Hot-Water Drilling in Ice with Near-Bottom Circulation
by Gaoli Zhao, Pavel G. Talalay, Xiaopeng Fan, Nan Zhang, Yunchen Liu, Ting Wang and Yanji Chen
Water 2022, 14(1), 127; https://doi.org/10.3390/w14010127 - 05 Jan 2022
Viewed by 1788
Abstract
Hot-water drilling in ice with near-bottom circulation is more advantageous than traditional hot-water drilling with all-over borehole circulation in terms of power consumption and weight. However, the drilling performance of this type of drill has been poorly studied. Initial experiments showed that drilling [...] Read more.
Hot-water drilling in ice with near-bottom circulation is more advantageous than traditional hot-water drilling with all-over borehole circulation in terms of power consumption and weight. However, the drilling performance of this type of drill has been poorly studied. Initial experiments showed that drilling with single-orifice nozzles did not proceed smoothly. To achieve the best drilling performance, nozzles with different orifice numbers and structures are evaluated in the present study. The testing results show that a single-orifice nozzle with a 3 mm nozzle diameter and a nine-jet nozzle with a forward angle of 35° had the highest rate of penetration (1.7–1.8 m h−1) with 5.6–6.0 kW heating power. However, the nozzles with backward holes ensured a smoother drilling process and a larger borehole, although the rate of penetration was approximately 13% slower. A comparison of the hollow and solid thermal tips showed that under the same experimental conditions, the hollow drill tip had a lower flow rate, higher outlet temperature, and higher rate of penetration. This study provides a prominent reference for drilling performance prediction and drilling technology development of hot-water drilling in ice with near-bottom circulation. Full article
(This article belongs to the Section Hydrogeology)
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13 pages, 2079 KiB  
Article
Geomatic-Based Flood Loss Assessment and Its Application in an Eastern City of China
by Youjie Jin, Jianyun Zhang, Na Liu, Chenxi Li and Guoqing Wang
Water 2022, 14(1), 126; https://doi.org/10.3390/w14010126 - 05 Jan 2022
Cited by 6 | Viewed by 2303
Abstract
Flash-flood disasters pose a serious threat to lives and property. To meet the increasing demand for refined and rapid assessment on flood loss, this study exploits geomatic technology to integrate multi-source heterogeneous data and put forward the comprehensive risk index (CRI) calculation with [...] Read more.
Flash-flood disasters pose a serious threat to lives and property. To meet the increasing demand for refined and rapid assessment on flood loss, this study exploits geomatic technology to integrate multi-source heterogeneous data and put forward the comprehensive risk index (CRI) calculation with the fuzzy comprehensive evaluation (FCE). Based on mathematical correlations between CRIs and actual losses of flood disasters in Weifang City, the direct economic loss rate (DELR) model and the agricultural economic loss rate (AELR) model were developed. The case study shows that the CRI system can accurately reflect the risk level of a flash-flood disaster. Both models are capable of simulating disaster impacts. The results are generally consistent with actual impacts. The quantified economic losses generated from simulation are close to actual losses. The spatial resolution is up to 100 × 100 m. This study provides a loss assessment method with high temporal and spatial resolution, which can quickly assess the loss of rainstorm and flood disasters. The method proposed in this paper, coupled with a case study, provides a reliable reference to loss assessment on flash floods caused disasters and will be helpful to the existing literature. Full article
(This article belongs to the Special Issue GIS Application: Flood Risk Management)
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22 pages, 4017 KiB  
Article
Identification of Hydrodynamic Dispersion Tensor by Optimization Algorithm Based LBM/CMA-ES Combination
by Hassan Smaoui, Lahcen Zouhri and Sami Kaidi
Water 2022, 14(1), 125; https://doi.org/10.3390/w14010125 - 05 Jan 2022
Cited by 1 | Viewed by 2045
Abstract
The hydrodynamic dispersion tensor (HDT) of a porous medium is a key parameter in engineering and environmental sciences. Its knowledge allows for example, to accurately predict the propagation of a pollution front induced by a surface (or subsurface) flow. This paper proposes a [...] Read more.
The hydrodynamic dispersion tensor (HDT) of a porous medium is a key parameter in engineering and environmental sciences. Its knowledge allows for example, to accurately predict the propagation of a pollution front induced by a surface (or subsurface) flow. This paper proposes a new mathematical model based on inverse problem-solving techniques to identify the HDT (noted D=) of the studied porous medium. We then showed that in practice, this new model can be written in the form of an integrated optimization algorithm (IOA). The IOA is based on the numerical solution of the direct problem (which solves the convection–diffusion type transport equation) and the optimization of the error function between the simulated concentration field and that observed at the application site. The partial differential equations of the direct model were solved by high resolution of (Δx=Δy=1 m) Lattice Boltzmann Method (LBM) whose computational code is named HYDRODISP-LBM (HYDRO-DISpersion by LBM). As for the optimization step, we opted for the CMA-ES (Covariance Matrix Adaptation-Evolution Strategy) algorithm. Our choice for these two methods was motivated by their excellent performance proven in the abundant literature. The paper describes in detail the operation of the coupling of the two computer codes forming the IOA that we have named HYDRODISP-LBM/CMA-ES. Finally, the IOA was applied at the Beauvais experimental site to identify the HDT D=. The geological analyzes of this site showed that the tensor identified by the IOA is in perfect agreement with the characteristics of the geological formation of the site which are connected with the mixing processes of the latter. Full article
(This article belongs to the Special Issue Methods and Tools for Assessment of Groundwater)
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21 pages, 5587 KiB  
Article
Geochemical Markers as a Tool for the Characterization of a Multi-Layer Urban Aquifer: The Case Study of Como (Northern Italy)
by Gilberto Binda, Francesca Frascoli, Davide Spanu, Maria F. Ferrario, Silvia Terrana, Roberto Gambillara, Sara Trotta, Paula J. Noble, Franz A. Livio, Andrea Pozzi and Alessandro M. Michetti
Water 2022, 14(1), 124; https://doi.org/10.3390/w14010124 - 05 Jan 2022
Cited by 7 | Viewed by 2553
Abstract
The analysis of geochemical markers is a known valid tool to explore the water sources and understand the main factors affecting natural water quality, which are known issues of interest in environmental science. This study reports the application of geochemical markers to characterize [...] Read more.
The analysis of geochemical markers is a known valid tool to explore the water sources and understand the main factors affecting natural water quality, which are known issues of interest in environmental science. This study reports the application of geochemical markers to characterize and understand the recharge areas of the multi-layer urban aquifer of Como city (northern Italy). This area presents a perfect case study to test geochemical markers: The hydrogeological setting is affected by a layered karst and fractured aquifer in bedrock, a phreatic aquifer hosted in Holocene sediments and connected with a large freshwater body (Lake Como); the aquifers recharge areas and the water geochemistry are unknown; the possible effect of the tectonic setting on water flow was overlooked. In total, 37 water samples were collected including water from two stacked aquifers and surface water to characterize hydrochemical features. Moreover, six sediment samples in the recent palustrine deposits of the Como subsurface were collected from cores and analyzed to understand the main geochemistry and mineralogy of the hosting material. The chemical analyses of water allow to observe a remarkable difference between the shallow and deep aquifers of the study area, highlighting different recharge areas, as well as a different permanence time in the aquifers. The sediment geochemistry, moreover, confirms the differences in trace elements derived from sediment-water interaction in the aquifers. Finally, an anomalous concentration of As in the Como deep aquifer was observed, suggesting the need of more detailed analyses to understand the origin of this element in water. This study confirms the potentials of geochemical markers to characterize main factors affecting natural water quality, as well as a tool for the reconstruction of recharge areas. Full article
(This article belongs to the Special Issue Geochemistry of Mineral Groundwater)
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13 pages, 2765 KiB  
Article
Degradation of Azo Dyes with Different Functional Groups in Simulated Wastewater by Electrocoagulation
by Yang Liu, Chenglong Li, Jia Bao, Xin Wang, Wenjing Yu and Lixin Shao
Water 2022, 14(1), 123; https://doi.org/10.3390/w14010123 - 05 Jan 2022
Cited by 23 | Viewed by 4429
Abstract
Increasing attention has been paid to the widespread contamination of azo dyes in water bodies globally. These chemicals can present high toxicity, possibly causing severe irritation of the respiratory tract and even carcinogenic effects. The present study focuses on the periodically reverse electrocoagulation [...] Read more.
Increasing attention has been paid to the widespread contamination of azo dyes in water bodies globally. These chemicals can present high toxicity, possibly causing severe irritation of the respiratory tract and even carcinogenic effects. The present study focuses on the periodically reverse electrocoagulation (PREC) treatment of two typical azo dyes with different functional groups, involving methyl orange (MO) and alizarin yellow (AY), using Fe-Fe electrodes. Based upon the comparative analysis of three main parameters, including current intensity, pH, and electrolyte, the optimal color removal rates for MO and AY could be achieved at a rate of up to 98.7% and 98.6%, respectively, when the current intensity is set to 0.6 A, the pH is set at 6.0, and the electrolyte is selected as NaCl. An accurate predicted method of response surface methodology (RSM) was established to optimize the PREC process involving the three parameters above. The reaction time was the main influence for both azo dyes, while the condition of PREC treatment for AY simulated wastewater was time-saving and energy conserving. According to the further UV–Vis spectrophotometry analysis throughout the procedure of the PREC process, the removal efficiency for AY was better than that of MO, potentially because hydroxyl groups might donate electrons to iron flocs or electrolyze out hydroxyl free radicals. The present study revealed that the functional groups might pose a vital influence on the removal efficiencies of the PREC treatment for those two azo dyes. Full article
(This article belongs to the Special Issue Innovative Technologies for Wastewater and Water Treatment)
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23 pages, 6406 KiB  
Article
Financial and Economic Investment Evaluation of Wastewater Treatment Plant
by Jasmina Ćetković, Miloš Knežević, Slobodan Lakić, Miloš Žarković, Radoje Vujadinović, Angelina Živković and Jelena Cvijović
Water 2022, 14(1), 122; https://doi.org/10.3390/w14010122 - 05 Jan 2022
Cited by 11 | Viewed by 10064
Abstract
Improved Cost-Benefit Analysis (CBA) analysis requires a broader analytical framework, in order to perceive each project individually from the perspective of potentially measurable and significant effects on the environment and society as a whole. The main goal of our paper is to assess [...] Read more.
Improved Cost-Benefit Analysis (CBA) analysis requires a broader analytical framework, in order to perceive each project individually from the perspective of potentially measurable and significant effects on the environment and society as a whole. The main goal of our paper is to assess the financial and economic justification for variant V3 (as the most technically optimal) of the wastewater treatment plant (WWTP) construction project in Nov Dojran, North Macedonia, with the purpose of advancing municipal infrastructure and environmental benefits from improved water treatment. Based on the economic analysis conducted, we conclude that the investment in the WWTP project is justified, because the economic internal rate of return is higher than the opportunity cost of capital (EIRR = 16.38%), the economic net present value is higher than 0, and EBCR (benefit-cost ratio) is greater than 1 (EBCR = 2.11). The highest environmental benefit of 49.2% in total environmental benefits is associated with nitrogen, while phosphorus is the next pollutant in the structure of environmental benefits at 46.1%. The environmental benefits of removing biological oxygen demand (BOD) and chemical oxygen demand (COD) are significantly less important, despite the removal of significant amounts of these pollutants during treatment. The situation is similar with suspended particles. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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13 pages, 1211 KiB  
Article
Heavy Metals and Nutrients Loads in Water, Soil, and Crops Irrigated with Effluent from WWTPs in Blantyre City, Malawi
by Raymond S. Malikula, Chikumbusko C. Kaonga, Harold W. T. Mapoma, Fabiano G. D. Thulu and Petra Chiipa
Water 2022, 14(1), 121; https://doi.org/10.3390/w14010121 - 05 Jan 2022
Cited by 6 | Viewed by 3073
Abstract
Heavy metals may cause acute and chronic toxic effects to humans and other organisms, hence the need to treat wastewater properly, as it contains these toxicants. This work aimed at assessing zinc, copper, cadmium, and chromium in water, soil, and plants that are [...] Read more.
Heavy metals may cause acute and chronic toxic effects to humans and other organisms, hence the need to treat wastewater properly, as it contains these toxicants. This work aimed at assessing zinc, copper, cadmium, and chromium in water, soil, and plants that are irrigated with effluent from Manase and Soche Wastewater Treatment Plants (WWTPs) in Blantyre, Malawi. Atomic Absorption Spectrophotometry (AAS) was used to assess the heavy metals. Heavy Metal Health Risk Assessment (HMHRA) on plants (vegetables) around both WWTPs was also conducted. Average daily dose (ADD) and target hazard quotients (THQ) were used to assess HMHRA. Physicochemical parameters were determined using standard methods from American Public Health Association (APHA). The heavy metal ranges were below detection limit (BDL) to 6.94 mg/L in water, 0.0003 to 4.48 mg/kg in soil, and 3 to 32 mg/L in plants. The results revealed that plants irrigated with effluent from WWTP had high values of aforementioned metals exceeding the Malawi Standards and WHO permissible limits. Furthermore, the health risk assessment values showed that vegetables consumed for a long period of time from Manase WWTP were likely to cause adverse health effects as compared to those from Soche WWTP. Full article
(This article belongs to the Special Issue New Perspective on Water Security Management)
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16 pages, 4033 KiB  
Article
Four Years of Sediment and Phosphorus Monitoring in the Kraichbach River Using Large-Volume Samplers
by Katharina Allion, Lisa Kiemle and Stephan Fuchs
Water 2022, 14(1), 120; https://doi.org/10.3390/w14010120 - 05 Jan 2022
Cited by 3 | Viewed by 1558
Abstract
Various sampling strategies come into operation to monitor water quality in rivers. Most frequently, grab samples are taken, but they are not suitable for recording the highly dynamic transport of solids and solid-bound pollutants. Composite samples reduce the influence of input and transport [...] Read more.
Various sampling strategies come into operation to monitor water quality in rivers. Most frequently, grab samples are taken, but they are not suitable for recording the highly dynamic transport of solids and solid-bound pollutants. Composite samples reduce the influence of input and transport dynamics and are better suited to determine the annual river loads. Large-volume samplers (LVSs) produce both a composite sample over a long period of time and an amount of solids which allows for further analyses. In the small sub-catchment area of the Kraichbach river in Baden-Wuerttemberg (Germany) two LVSs have been installed to sample the river flow. The concentration of solids and phosphorus in the supernatant water and the settled sediment in the sampler have been determined and mean concentrations have been derived. Annual river loads were calculated in combination with discharge data from the nearby gauging station. Two sampling strategies of the LVS were tested and compared. For the first strategy, the LVS was used to collect quasi-continuous composite samples throughout the year, whereas, with the second strategy, samples were taken specifically for different flow conditions (low, mean and high flow). This study compares the advantages and constraints of both strategies. Results indicate that the first strategy is better suited to determine annual river loads. Quasi-continuous large-volume composite sampling is recommended for further monitoring campaigns. Full article
(This article belongs to the Special Issue Monitoring, Modelling and Management of Water Quality II)
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14 pages, 2672 KiB  
Article
Aspergillus niger Culture Filtrate (ACF) Mediated Biocontrol of Enteric Pathogens in Wastewater
by Suja Subhash, Pradeesh Babu, Amrutha Vijayakumar, Reshma Alookaran Suresh, Ajith Madhavan, Bipin Gopalakrishnan Nair and Sanjay Pal
Water 2022, 14(1), 119; https://doi.org/10.3390/w14010119 - 05 Jan 2022
Cited by 6 | Viewed by 4658
Abstract
Robust control of pathogens in sewage facilitates safe reuse of wastewater rich in valuable nutrients for potential valorization through biological means. Aspergillus niger is widely reported in bioremediation of wastewater but studies on control of enteric pathogens in sewage are very sparse. So, [...] Read more.
Robust control of pathogens in sewage facilitates safe reuse of wastewater rich in valuable nutrients for potential valorization through biological means. Aspergillus niger is widely reported in bioremediation of wastewater but studies on control of enteric pathogens in sewage are very sparse. So, this study aimed at exploring the antibacterial and nematicidal activity of A. niger culture filtrate (ACF). Antibacterial activity of ACF on enteric pathogens (Klebsiella pneumoniae, Pseudomonas aeruginosa, Vibrio cholerae, Salmonella enterica, Shigella dysenteriae, Escherichia coli, Staphylococcus aureus, Klebsiella variicola) was determined by spectrophotometric growth analysis, resazurin based viability assay and biofilm formation assay. ACF showed inhibition against all enteric pathogens except Pseudomonas aeruginosa. Nematicidal studies on Caenorhabditis elegans showed 85% egg hatch inhibition and 52% mortality of L1 larvae. Sewage treatment with ACF at 1:1 (v/v) showed 2–3 log reduction in coliforms, Klebsiella, Shigella, Salmonella, S. aureus and Vibrio except Pseudomonas, indicating significant alteration of complex microbial dynamics in wastewater. Application of ACF can potentially be used as a robust biocontrol strategy against infectious microbes in wastewater and subsequent valorization by cultivating beneficial Pseudomonas. Full article
(This article belongs to the Special Issue Biotechnology Applications in Water and Wastewater Treatment)
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18 pages, 14558 KiB  
Article
Climate Change Attribution in the Lena and Selenga River Runoff: An Evaluation Based on the Earth System and Regional Hydrological Models
by Andrey Kalugin
Water 2022, 14(1), 118; https://doi.org/10.3390/w14010118 - 05 Jan 2022
Cited by 12 | Viewed by 2229
Abstract
The main goal of this study was to obtain the attribution results of a physical assessment of the modern hydrological consequences of separately natural and anthropogenic components of climate change, based on the synthesis of detailed process-based models of river runoff formation and [...] Read more.
The main goal of this study was to obtain the attribution results of a physical assessment of the modern hydrological consequences of separately natural and anthropogenic components of climate change, based on the synthesis of detailed process-based models of river runoff formation and an ensemble of Earth system models (ESMs) within the large river basins in Eastern Siberia. This approach allows calculating the river flow using ESM-based data over the observation period under two scenarios, considering: (1) the anthropogenic impact of increasing greenhouse gas emissions and (2) only internal fluctuations of the climate system and natural external forcing. According to the results of the numerical experiments, the attributions of anthropogenic components of climate change in the dynamics of the Lena runoff are weak, i.e., during the observation period, the Lena River flow statistically significantly increases, but it occurs mainly due to natural climate variability. The changes in the Selenga runoff are intensely influenced by the anthropogenic component of climate change. Since the 1970s, the Selenga runoff increased under natural climatic conditions, but since the mid-1980s, it decreased under anthropogenic greenhouse gas emissions, due to reduced summer precipitation. This was the main reason for the last low-water period of 1996–2017 in the Selenga basin. Full article
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13 pages, 2467 KiB  
Article
Aquatic Vegetation Loss and Its Implication on Climate Regulation in a Protected Freshwater Wetland of Po River Delta Park (Italy)
by Mattias Gaglio, Mariano Bresciani, Nicola Ghirardi, Alexandra Nicoleta Muresan, Mattia Lanzoni, Fabio Vincenzi, Giuseppe Castaldelli and Elisa Anna Fano
Water 2022, 14(1), 117; https://doi.org/10.3390/w14010117 - 05 Jan 2022
Cited by 5 | Viewed by 2308
Abstract
Aquatic vegetation loss caused substantial decrease of ecosystem processes and services during the last decades, particularly for the capacity of these ecosystems to sequester and store carbon from the atmosphere. This study investigated the extent of aquatic emergent vegetation loss for the period [...] Read more.
Aquatic vegetation loss caused substantial decrease of ecosystem processes and services during the last decades, particularly for the capacity of these ecosystems to sequester and store carbon from the atmosphere. This study investigated the extent of aquatic emergent vegetation loss for the period 1985–2018 and the consequent effects on carbon sequestration and storage capacity of Valle Santa wetland, a protected freshwater wetland dominated by Phragmites australis located in the Po river delta Park (Northern Italy), as a function of primary productivity and biomass decomposition, assessed by means of satellite images and experimental measures. The results showed an extended loss of aquatic vegetated habitats during the considered period, with 1989 being the year with higher productivity. The mean breakdown rates of P. australis were 0.00532 d−1 and 0.00228 d−1 for leaf and stem carbon content, respectively, leading to a predicted annual decomposition of 64.6% of the total biomass carbon. For 2018 the carbon sequestration capacity was estimated equal to 0.249 kg C m−2 yr−1, while the carbon storage of the whole wetland was 1.75 × 103 t C (0.70 kg C m−2). Nonetheless, despite the protection efforts over time, the vegetation loss occurred during the last decades significantly decreased carbon sequestration and storage by 51.6%, when comparing 2018 and 1989. No statistically significant effects were found for water descriptors. This study demonstrated that P. australis-dominated wetlands support important ecosystem processes and should be regarded as an important carbon sink under an ecosystem services perspective, with the aim to maximize their capacity to mitigate climate change. Full article
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18 pages, 3144 KiB  
Article
Machine Learning Approach to Predict Quality Parameters for Bacterial Consortium-Treated Hospital Wastewater and Phytotoxicity Assessment on Radish, Cauliflower, Hot Pepper, Rice and Wheat Crops
by Aneeba Rashid, Safdar A. Mirza, Ciara Keating, Umer Z. Ijaz, Sikander Ali and Luiza C. Campos
Water 2022, 14(1), 116; https://doi.org/10.3390/w14010116 - 05 Jan 2022
Cited by 3 | Viewed by 2655
Abstract
Raw hospital wastewater is a source of excessive heavy metals and pharmaceutical pollutants. In water-stressed countries such as Pakistan, the practice of unsafe reuse by local farmers for crop irrigation is of major concern. In our previous work, we developed a low-cost bacterial [...] Read more.
Raw hospital wastewater is a source of excessive heavy metals and pharmaceutical pollutants. In water-stressed countries such as Pakistan, the practice of unsafe reuse by local farmers for crop irrigation is of major concern. In our previous work, we developed a low-cost bacterial consortium wastewater treatment method. Here, in a two-part study, we first aimed to find what physico-chemical parameters were the most important for differentiating consortium-treated and untreated wastewater for its safe reuse. This was achieved using a Kruskal–Wallis test on a suite of physico-chemical measurements to find those parameters which were differentially abundant between consortium-treated and untreated wastewater. The differentially abundant parameters were then input to a Random Forest classifier. The classifier showed that ‘turbidity’ was the most influential parameter for predicting biotreatment. In the second part of our study, we wanted to know if the consortium-treated wastewater was safe for crop irrigation. We therefore carried out a plant growth experiment using a range of popular crop plants in Pakistan (Radish, Cauliflower, Hot pepper, Rice and Wheat), which were grown using irrigation from consortium-treated and untreated hospital wastewater at a range of dilutions (turbidity levels) and performed a phytotoxicity assessment. Our results showed an increasing trend in germination indices and a decreasing one in phytotoxicity indices in plants after irrigation with consortium-treated hospital wastewater (at each dilution/turbidity measure). The comparative study of growth between plants showed the following trend: Cauliflower > Radish > Wheat > Rice > Hot pepper. Cauliflower was the most adaptive plant (PI: −0.28, −0.13, −0.16, −0.06) for the treated hospital wastewater, while hot pepper was susceptible for reuse; hence, we conclude that bacterial consortium-treated hospital wastewater is safe for reuse for the irrigation of cauliflower, radish, wheat and rice. We further conclude that turbidity is the most influential parameter for predicting bio-treatment efficiency prior to water reuse. This method, therefore, could represent a low-cost, low-tech and safe means for farmers to grow crops in water stressed areas. Full article
(This article belongs to the Section Wastewater Treatment and Reuse)
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13 pages, 11157 KiB  
Article
UASB Performance and Perspectives in Urban Wastewater Treatment at Sub-Mesophilic Operating Temperature
by Daniele Cecconet, Arianna Callegari and Andrea G. Capodaglio
Water 2022, 14(1), 115; https://doi.org/10.3390/w14010115 - 05 Jan 2022
Cited by 11 | Viewed by 3854
Abstract
UASBs present several advantages compared to conventional wastewater treatment processes, including relatively low construction cost facilities, low excess sludge production, plain operation and maintenance, energy generation in the form of biogas, robustness in terms of COD removal efficiency, pH stability, and recovery time. [...] Read more.
UASBs present several advantages compared to conventional wastewater treatment processes, including relatively low construction cost facilities, low excess sludge production, plain operation and maintenance, energy generation in the form of biogas, robustness in terms of COD removal efficiency, pH stability, and recovery time. Although anaerobic treatment is possible at every temperature, colder climates lead to lower process performance and biogas production. These factors can be critical in determining the applicability and sustainability of this technology for the treatment of urban wastewater at low operating temperature. The purpose of this study is the performance evaluation of a pilot-scale (2.75 m3) UASB reactor for treatment of urban wastewater at sub-mesophilic temperature (25 °C), below the optimal range for the process, as related to biogas production and organic matter removal. The results show that, despite lower methane production and COD removal efficiency compared to operation under ideal conditions, a UASB can still achieve satisfactory performance, and although not sufficient to grant effluent discharge requirements, it may be used as a pretreatment step for carbon removal with some degree of energy recovery. Options for UASB pretreatment applications in municipal WWTPs are discussed. Full article
(This article belongs to the Topic Emerging Solutions for Water, Sanitation and Hygiene)
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19 pages, 5683 KiB  
Article
Sustainable Water Allocation in Umarkhed Taluka through Optimization of Reservoir Operation in the Wardha Sub-Basin, India
by Md Atif Ibne Haidar, Daniel Che and Larry W. Mays
Water 2022, 14(1), 114; https://doi.org/10.3390/w14010114 - 05 Jan 2022
Viewed by 2086
Abstract
Climate change is causing shifts in seasonal weather patterns and variation in seasonal time scales in India. Factors including uneven distribution of water, faulty agricultural practices and water policies, low prices of farm products, and debt are leading farmers to commit suicide in [...] Read more.
Climate change is causing shifts in seasonal weather patterns and variation in seasonal time scales in India. Factors including uneven distribution of water, faulty agricultural practices and water policies, low prices of farm products, and debt are leading farmers to commit suicide in Umarkhed Taluka of the Yavatmal District. This study aimed to develop a sustainable solution to water scarcity in the surrounding watershed by introducing optimization modeling in reservoir operation. Past studies have conducted different hydrologic analyses to address the water scarcity issue in this region. However, none of the studies incorporated optimization in their models. This study developed an integrated hydrologic and optimization model that can predict the daily reservoir releases for climate change scenarios from 2020 to 2069 based upon Representative Concentration Pathway (RCP-4.5 and RCP-8.5) climate change scenarios from 2020 to 2069. The integrated simulations were able to deliver around 19% more water than the historical discharge at the most downstream station of the Wardha Watershed. The simulated approaches store less water than the actual unoptimized scenario and deliver water when there is a need at the downstream locations. Finally, because the downstream locations of the Wardha Watershed receive more water, a localized storage system can be developed and a transfer method can be utilized to deliver sufficient water to the Umarkhed Taluka. Full article
(This article belongs to the Section Urban Water Management)
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22 pages, 3158 KiB  
Article
Geochemical Partitioning of Heavy Metals and Metalloids in the Ecosystems of Abandoned Mine Sites: A Case Study within the Moscow Brown Coal Basin
by Ivan Semenkov, Anna Sharapova, Sergey Lednev, Natalia Yudina, Andrey Karpachevskiy, Galya Klink and Tatiana Koroleva
Water 2022, 14(1), 113; https://doi.org/10.3390/w14010113 - 05 Jan 2022
Cited by 7 | Viewed by 2846
Abstract
Significant environmental impacts of mining activities connected with high-sulfur materials result from the production of acid mine drainage and potentially toxic elements, which easily migrate to adjacent ecosystems due to the typical absence of vegetation on spoil heaps and toeslope talus mantle. In [...] Read more.
Significant environmental impacts of mining activities connected with high-sulfur materials result from the production of acid mine drainage and potentially toxic elements, which easily migrate to adjacent ecosystems due to the typical absence of vegetation on spoil heaps and toeslope talus mantle. In this paper, we present the results of the first comprehensive study of the ecosystems affected by acidic and metal-enriched (Al, Ca, Co, Cu, Fe, Mg, Mn, Ni, and Zn) mine drainage conducted at spoil heaps and adjacent talus mantle under semihumid climate conditions within the Moscow Brown Coal Basin (Central Russian Upland, Tula Region, Russia). A total of 162 samples were collected, including 98 soil samples, 42 surface water samples, and 22 plant samples (aerial tissues of birch). Coal talus mantle materials of Regosols were characterized by the increased concentration of water-soluble Ca, K, Mg, and S, and all mobile fractions of Al, Co, S, and Zn. The chemical composition of birch samples within the zones affected by acid mine drainage differed insignificantly from those in the unpolluted ecosystems with black soils, due to the high tolerance of birch to such conditions. Differences between the affected and undisturbed sites in terms of the chemical composition decreased in the following order: waters > soils > plants. The geochemical characterization of plants and soils in coal mining areas is essential for the mitigation of negative consequences of mining activities. Full article
(This article belongs to the Special Issue Geochemistry of Landscape and Soil)
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19 pages, 3602 KiB  
Article
Hydraulic Planning in Insular Urban Territories: The Case of Madeira Island—São Vicente
by Sérgio Lousada, Leonardo Gonçalves and Alper Atmaca
Water 2022, 14(1), 112; https://doi.org/10.3390/w14010112 - 05 Jan 2022
Cited by 11 | Viewed by 1882
Abstract
This study aims to examine the flood propensity of the main watercourse of São Vicente drainage basin and, if relevant, to propose two methodologies to alleviate the impacts, i.e., detention basin sizing and riverbed roughness coefficient adjustment. Geomorphological data were obtained from the [...] Read more.
This study aims to examine the flood propensity of the main watercourse of São Vicente drainage basin and, if relevant, to propose two methodologies to alleviate the impacts, i.e., detention basin sizing and riverbed roughness coefficient adjustment. Geomorphological data were obtained from the watershed characterization process and used through the SIG ArcGIS software for the flood propensity assessment and then for the calculation of the expected peak flow rate for a return period of 100 years through the Gumbel Distribution. Subsequently, the drainage capacity of the river mouth was verified using the Manning-Strickler equation, in order to establish whether the river mouth of the watershed has the capacity to drain the entire volume of rainwater in a severe flood event. In summary, it was possible to conclude that São Vicente’s watershed river mouth is not able to completely drain the rain flow for the established return period. Thus, its drainage capacity was guaranteed by modifying the walls and streambed roughness coefficient and by sizing the detention basin using the Dutch and the Simplified Triangular Hydrograph methods. Full article
(This article belongs to the Section Oceans and Coastal Zones)
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11 pages, 2950 KiB  
Article
Effect of Radio-Frequency Treatment on the Changes of Dissolved Organic Matter in Rainwater
by Ariadi Hazmi, Maulana Yusup Rosadi, Reni Desmiarti and Fusheng Li
Water 2022, 14(1), 111; https://doi.org/10.3390/w14010111 - 05 Jan 2022
Cited by 2 | Viewed by 3769
Abstract
Rainwater is a potential source of drinking water, but has various components of dissolved organic matter (DOM). DOM is a reservoir of potential hazards in drinking water. Therefore, a new method is required to purify rainwater as a drinking water source in terms [...] Read more.
Rainwater is a potential source of drinking water, but has various components of dissolved organic matter (DOM). DOM is a reservoir of potential hazards in drinking water. Therefore, a new method is required to purify rainwater as a drinking water source in terms of DOM aspects. A radio-frequency (RF) treatment system is introduced here to purify source water with a small possibility of contamination. RF is generated by applying a frequency of 1.5 MHz through a glass reactor with a diameter of 2 mm which is wrapped by a 2 mm copper wire. The results demonstrate that UV260 value and dissolved organic carbon (DOC) are reduced during RF treatment. DOC was reduced by a lower amount compared to UV260, suggesting the partial transformation of bio-refractory DOM. A fluorescence excitation-emission matrix showed that humic-like substances in rainwater were reduced faster than protein-like ones, indicating that humic-like substances are susceptible to reduction by RF treatment. The results offer information on the use of RF treatment in a rainwater purification process for the production of drinking water. Full article
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22 pages, 3043 KiB  
Article
Hunting for Information in Streamflow Signatures to Improve Modelled Drainage
by Raphael Schneider, Simon Stisen and Anker Lajer Højberg
Water 2022, 14(1), 110; https://doi.org/10.3390/w14010110 - 05 Jan 2022
Cited by 6 | Viewed by 2205
Abstract
About half of the Danish agricultural land is drained artificially. Those drains, mostly in the form of tile drains, have a significant effect on the hydrological cycle. Consequently, the drainage system must also be represented in hydrological models that are used to simulate, [...] Read more.
About half of the Danish agricultural land is drained artificially. Those drains, mostly in the form of tile drains, have a significant effect on the hydrological cycle. Consequently, the drainage system must also be represented in hydrological models that are used to simulate, for example, the transport and retention of chemicals. However, representation of drainage in large-scale hydrological models is challenging due to scale issues, lacking data on the distribution of drain infrastructure, and lacking drain flow observations. This calls for more indirect methods to inform such models. Here, we investigate the hypothesis that drain flow leaves a signal in streamflow signatures, as it represents a distinct streamflow generation process. Streamflow signatures are indices characterizing hydrological behaviour based on the hydrograph. Using machine learning regressors, we show that there is a correlation between signatures of simulated streamflow and simulated drain fraction. Based on these insights, signatures relevant to drain flow are incorporated in hydrological model calibration. A distributed coupled groundwater–surface water model of the Norsminde catchment, Denmark (145 km2) is set up. Calibration scenarios are defined with different objective functions; either using conventional stream flow metrics only, or a combination with hydrological signatures. We then evaluate the results from the different scenarios in terms of how well the models reproduce observed drain flow and spatial drainage patterns. Overall, the simulation of drain in the models is satisfactory. However, it remains challenging to find a direct link between signatures and an improvement in representation of drainage. This is likely attributable to model structural issues and lacking flexibility in model parameterization. Full article
(This article belongs to the Section Water, Agriculture and Aquaculture)
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12 pages, 1443 KiB  
Article
A First Glimpse on Cold-Adapted PCB-Oxidizing Bacteria in Edmonson Point Lakes (Northern Victoria Land, Antarctica)
by Maria Papale, Angelina Lo Giudice, Alessandro Ciro Rappazzo, Maurizio Azzaro and Carmen Rizzo
Water 2022, 14(1), 109; https://doi.org/10.3390/w14010109 - 05 Jan 2022
Cited by 1 | Viewed by 1666
Abstract
Antarctic freshwater ecosystems are especially vulnerable to human impacts. Polychlorobiphenyls (PCBs) are persistent organic pollutants that have a long lifetime in the environment. Despite their use having either been phased out or restricted, they are still found in nature, also in remote areas. [...] Read more.
Antarctic freshwater ecosystems are especially vulnerable to human impacts. Polychlorobiphenyls (PCBs) are persistent organic pollutants that have a long lifetime in the environment. Despite their use having either been phased out or restricted, they are still found in nature, also in remote areas. Once in the environment, the fate of PCBs is strictly linked to bacteria which represent the first step in the transfer of toxic compounds to higher trophic levels. Data on PCB-oxidizing bacteria from polar areas are still scarce and fragmented. In this study, the occurrence of PCB-oxidizing cold-adapted bacteria was evaluated in water and sediment of four coastal lakes at Edmonson Point (Northern Victoria Land, Antarctica). After enrichment with biphenyl, 192 isolates were obtained with 57 of them that were able to grow in the presence of the PCB mixture Aroclor 1242, as the sole carbon source. The catabolic gene bphA, as a proxy for PCB degradation potential, was harbored by 37 isolates (out of 57), mainly affiliated to the genera Salinibacterium, Arthrobacter (among Actinobacteria) and Pusillimonas (among Betaproteobacteria). Obtained results enlarge our current knowledge on cold-adapted PCB-oxidizing bacteria and pose the basis for their potential application as a valuable eco-friendly tool for the recovery of PCB-contaminated cold sites. Full article
(This article belongs to the Special Issue Microbial Life in the Cold: A Focus on Extreme Aquatic Environments)
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16 pages, 4549 KiB  
Article
Runoff Prediction Based on the Discharge of Pump Stations in an Urban Stream Using a Modified Multi-Layer Perceptron Combined with Meta-Heuristic Optimization
by Won Jin Lee and Eui Hoon Lee
Water 2022, 14(1), 99; https://doi.org/10.3390/w14010099 - 04 Jan 2022
Cited by 7 | Viewed by 1919
Abstract
Runoff in urban streams is the most important factor influencing urban inundation. It also affects inundation in other areas as various urban streams and rivers are connected. Current runoff predictions obtained using a multi-layer perceptron (MLP) exhibit limited accuracy. In this study, the [...] Read more.
Runoff in urban streams is the most important factor influencing urban inundation. It also affects inundation in other areas as various urban streams and rivers are connected. Current runoff predictions obtained using a multi-layer perceptron (MLP) exhibit limited accuracy. In this study, the runoff of urban streams was predicted by applying an MLP using a harmony search (MLPHS) to overcome the shortcomings of MLPs using existing optimizers and compared with the observed runoff and the runoff predicted by an MLP using a real-coded genetic algorithm (RCGA). Furthermore, the results of the MLPHS were compared with the results of the MLP with existing optimizers such as the stochastic gradient descent, adaptive gradient, and root mean squared propagation. The runoff of urban steams was predicted based on the discharge of each pump station and rainfall information. The results obtained with the MLPHS exhibited the smallest error of 39.804 m3/s when compared to the peak value of the observed runoff. The MLPHS gave more accurate runoff prediction results than the MLP using the RCGA and that using existing optimizers. The accurate prediction of the runoff in an urban stream using an MLPHS based on the discharge of each pump station is possible. Full article
(This article belongs to the Special Issue Advances in Real-Time Flood Forecasting)
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15 pages, 20600 KiB  
Article
Probabilistic Minimum Night Flow Estimation in Water Distribution Networks and Comparison with the Water Balance Approach: Large-Scale Application to the City Center of Patras in Western Greece
by Athanasios V. Serafeim, George Kokosalakis, Roberto Deidda, Irene Karathanasi and Andreas Langousis
Water 2022, 14(1), 98; https://doi.org/10.3390/w14010098 - 04 Jan 2022
Cited by 12 | Viewed by 3497
Abstract
Quantification of water losses (WL) in water distribution networks (WDNs) is a crucial task towards the development of proper strategies to reduce them. Currently, WL estimation methods rely on semi-empirical assumptions and different implementation strategies that increase the uncertainty of the obtained estimates. [...] Read more.
Quantification of water losses (WL) in water distribution networks (WDNs) is a crucial task towards the development of proper strategies to reduce them. Currently, WL estimation methods rely on semi-empirical assumptions and different implementation strategies that increase the uncertainty of the obtained estimates. In this work, we compare the effectiveness and robustness of two widely applied WL estimation approaches found in the international literature: (a) the water balance, or top-down, approach introduced by the International Water Association (IWA), and (b) the bottom-up or minimum night flow (MNF) approach, based on a recently proposed probabilistic MNF estimation method. In doing so, we use users’ consumption and flow-pressure data from the 4 largest pressure management areas (PMAs) of the WDN of the city of Patras (the third largest city in Greece), which consist of more than 200 km of pipeline, cover the entire city center of Patras, and serve approximately 58,000 consumers. The obtained results show that: (a) when MNF estimation is done in a rigorous statistical setting from high resolution flow-pressure timeseries, and (b) there is sufficient understanding of the consumption types and patterns during day and night hours, the two approaches effectively converge, allowing for more reliable estimation of the individual WL components. In addition, when high resolution flow-pressure timeseries are available at the inlets of PMAs, the suggested version of the bottom-up approach with probabilistic estimation of MNF should be preferred as less sensitive, while allowing for confidence interval estimation of the individual components of water losses and development of proper strategies to reduce them. Full article
(This article belongs to the Section Urban Water Management)
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13 pages, 4002 KiB  
Article
Integrating Stable Isotopes with Mean Residence Time Estimation to Characterize Groundwater Circulation in a Metamorphic Geothermal Field in Yilan, Taiwan
by Ching-Huei Kuo, Pi-Yi Li, Jun-Yi Lin and Yi-Lin Chen
Water 2022, 14(1), 97; https://doi.org/10.3390/w14010097 - 04 Jan 2022
Cited by 1 | Viewed by 1770
Abstract
This paper presents a water circulation model by combing oxygen and hydrogen stable isotopes and mean residence time (MRT) estimation in a high-temperature metamorphic geothermal field, Tuchen, in Yilan, Taiwan. A total of 18 months of oxygen and hydrogen stable isotopes of surface [...] Read more.
This paper presents a water circulation model by combing oxygen and hydrogen stable isotopes and mean residence time (MRT) estimation in a high-temperature metamorphic geothermal field, Tuchen, in Yilan, Taiwan. A total of 18 months of oxygen and hydrogen stable isotopes of surface water and thermal water show the same variation pattern, heavier values in summer and lighter values in the rest of the year. A shift of δ18O with a relative constant δD indicates the slow fluid–rock interaction process in the study area. Two adjacent watersheds, the Tianguer River and Duowang River, exhibit different isotopic values and imply different recharge altitudes. The seasonal variation enabled us to use stable isotope to estimate mean residence time of groundwater in the study area. Two wells, 160 m and 2200 m deep, were used to estimate mean residence time of the groundwater. Deep circulation recharges from higher elevations, with lighter isotopic values, 5.9‰ and 64‰ of δ18O and δD, and a longer mean residence time, 1148 days, while the shallow circulation comes from another source with heavier values, 5.7‰ and 54.4‰ of δ18O and δD, and a shorter mean residence time, 150 days. A two-circulation model was established based on temporal and spatial distribution characteristics of stable isotopes and the assistance of MRT. This study demonstrates the usefulness of the combined usage for further understanding water circulation of other various temperatures of metamorphic geothermalfields. Full article
(This article belongs to the Section Hydrogeology)
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25 pages, 7898 KiB  
Article
Accurate Storm Surge Prediction with a Parametric Cyclone and Neural Network Hybrid Model
by Wei-Ting Chao and Chih-Chieh Young
Water 2022, 14(1), 96; https://doi.org/10.3390/w14010096 - 04 Jan 2022
Cited by 6 | Viewed by 3161
Abstract
Storm surges are one of the most devastating coastal disasters. Numerous efforts have continuously been made to achieve better prediction of storm surge variation. In this paper, we propose a parametric cyclone and neural network hybrid model for accurate, long lead-time storm surge [...] Read more.
Storm surges are one of the most devastating coastal disasters. Numerous efforts have continuously been made to achieve better prediction of storm surge variation. In this paper, we propose a parametric cyclone and neural network hybrid model for accurate, long lead-time storm surge prediction. The model was applied to the northeastern coastal region of Taiwan, i.e., Longdong station. A total of 14 historical typhoon events were used for model training and validation, and the results and questions associated with this hybrid approach carefully discussed. Overall, the proposed method reduced the complexity of network structure while retaining the important typhoon indicators. In particular, local pressure and winds estimated from the storm parameters through physically-based parametric cyclone models allow for inferring the possible future influence of a typhoon, unlike the simple collection and direct usage of observation data from local stations in earlier works. Meanwhile, the error-tolerance capability of the neural network alleviated some discrepancy in the model inputs and enabled good surge prediction. Further, the proposed method showed better and faster convergence thanks to the retention of storm information and the reduced dimensions of the search space. The hybrid model presented excellent performance or maintained reasonable capability for short lead-time and long lead-time storm surge prediction. Compared with the pure neural network model under the same network dimensions, the present model demonstrated great improvement in accuracy as the prediction lead time increased to 8 h, e.g., 33–40% (13–21%) and 32–37% (18–29%) RMSE and CE, respectively, in the training/validation phase. Full article
(This article belongs to the Section Oceans and Coastal Zones)
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16 pages, 2233 KiB  
Article
Anodic Oxidation of Industrial Winery Wastewater Using Different Anodes
by Yeney Lauzurique, Lidia Carolina Espinoza, César Huiliñir, Verónica García and Ricardo Salazar
Water 2022, 14(1), 95; https://doi.org/10.3390/w14010095 - 04 Jan 2022
Cited by 13 | Viewed by 2493
Abstract
Winery wastewater represents the largest waste stream in the wine industry. This deals with the mineralization of the organic matter present in winery wastewater using anodic oxidation and two types of anodes—namely, a boron-doped diamond electrode (BDD) and two mixed metal oxides (MMO), [...] Read more.
Winery wastewater represents the largest waste stream in the wine industry. This deals with the mineralization of the organic matter present in winery wastewater using anodic oxidation and two types of anodes—namely, a boron-doped diamond electrode (BDD) and two mixed metal oxides (MMO), one with the nominal composition Ti/Ru0.3Ti0.7O2 and the other with Ti/Ir0.45Ta0.55O2. To conduct the study, the variability of different quality parameters for winery wastewater from the Chilean industry was measured during eight months. A composite sample was treated using anodic oxidation without the addition of supporting electrolyte, and the experiments were conducted at the natural pH of the industrial wastewater. The results show that this effluent has a high content of organic matter (up to 3025 ± 19 mg/L of total organic carbon (TOC)), which depends on the time of the year and the level of wine production. With MMO electrodes, TOC decreased by 2.52% on average after 540 min, which may be attributed to the presence of intermediate species that could not be mineralized. However, when using a BDD electrode, 85% mineralization was achieved due to the higher generation of hydroxyl radicals. The electrolyzed sample contained oxamic, acetic, and propionic acid as well as different ions such as sulfate, chloride, nitrate, and phosphate. These ions can contribute to the formation of different species such as active species of chlorine, persulfate, and perphosphate, which can improve the oxidative power of the system. Full article
(This article belongs to the Special Issue Advanced Electrochemical Technologies for Water Treatment)
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