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  • 1
    Publication Date: 2018-07-02
    Description: Publication date: Available online 30 June 2018 Source: Water Science Author(s): M. Gomo This article presents and discusses conceptual hydrogeochemical characteristics of dolomite and calcite acid mine drainage (AMD) neutralised circumneutral groundwater system. The conceptual discussions are based on the consideration of calcite and dolomite AMD buffering hydrogeochemical processes. Using theoretical chemical reaction stoichiometry, predictions are made for molar ratios of associated AMD – calcite and dolomite buffering reaction products (SO 4 2− , Ca 2+ and Mg 2+ ). Comparison is made between stoichiometrically predicted molar ratios of SO 4 2− /Ca 2+ , SO 4 2− /Mg 2+ , Ca 2+ /Mg 2+ and field data from previous studies in South Africa. There is a close match between stoichiometrically predicted molar ratios of the calcite and dolomite AMD neutralisation reaction products and field data. The results provide basis to improve the conceptual understanding of hydrogeochemical processes associated with dolomite and calcite AMD neutralisation which is important for field investigations related to mine-water quality, water management, remediation and overall environmental protection. Results further demonstrates the potential usefulness of relating ion concentration molar ratios of field measurements to stoichiometric predictions as a tool to identify hydrogeochemical processes controlling the evolution of groundwater chemistry.
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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  • 2
    Publication Date: 2018-07-02
    Description: Publication date: Available online 30 June 2018 Source: Water Science Author(s): Laniyi L. Ladokun, Bolaji F. Sule, Kajogbola R. Ajao, Adeniyi G. Adeogun This paper focuses on assessing the potential and feasibility of increasing the hydropower production of Nigeria’s three main hydropower stations by installing hydrokinetic turbines behind the existing dams. The hydrokinetic turbines will capture additional power from the energy remaining in water currents exiting draft-tube outlets and tailraces of the dams. A 2.54 m 2 prototype hydrokinetic turbine system being developed by the National Centre for Hydropower Research and Development, Nigeria was used to theoretically estimate the increased power generation capability of the stations. Preliminary results showed that there are considerable potentials in the range of kilowatts and megawatts in each hydropower station to augment the existing power infrastructure and this can be harnessed to alleviate the existing power problems in the country. It may also be an additional way of generating clean energy to mitigate the effect of climate change.
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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  • 3
    Publication Date: 2018-07-02
    Description: Publication date: Available online 30 June 2018 Source: Water Science Author(s): Muhammad Ashraf, Ahmed Hussein Soliman, Entesar El-Ghorab, Alaa El Zawahry Understanding the failure mechanisms of embankment dams due to overtopping is essential for the design of flood mitigation, flood mapping, and flood warning systems. The breach process in embankment dams can be characterized using breach parameters such as breach opening dimensions, time of breach formation, and peak breach outflow. The main objective of this study is to derive new set of statistical equations to predict the target breach parameters. A database of 126 events of embankment failure was collected and then multiple nonlinear regression analysis is used to derive the new set of equations and the uncertainty in the computed parameters was quantified. Finally, five large-scale overtopping failure tests were conducted on cohesive and non-cohesive soils embankments. The derived breach parameters equations showed good agreement with the results of the physical models for non-cohesive soil embankments, while the failure of cohesive soil embankments varied significantly with soil properties; indicating that breach parameters in cohesive soil embankment should be computed based on not only embankment dimensions but soil properties as well.
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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  • 4
    Publication Date: 2018-05-21
    Description: Publication date: Available online 19 May 2018 Source: Water Science Author(s): Hend Samir Abdel Fattah Atta, Abdel Wahab Mohamed Amer, Samir Abdel Fattah Atta The present study is an attempt to evaluate the availability of using the groundwater for different purposes at Manfalut District, Assuit Governorate. Chemical analysis of water samples in the study area at Manfalut District are located between latitudes 27°00′ & 27°30′ North and longitudes 30°30′ & 31°00′ East. It is bounded to: the East by the River Nile, the North by El-Qusiya District, the South by Assuit District and the West by the Western Desert. The concentration of total dissolved salts (TDS) of groundwater in the studied area ranges from 256 to 2816 ppm. The minimum TDS 256 ppm was recorded in the area located near Naga Hammadi canal. The maximum TDS was found in the western part near desert. This TDS level has been affected by the soil leaching and the diffusion of marine groundwater from the Miocene aquifer located in the west. The well samples which can be used in drinking purposes according to WHO standards are located in west area of River Nile, while the sample located at the second region in the western area cannot be used for drinking or domestic uses due to very high salinity. The concentrations of trace elements in the groundwater of Manfalut District were generally within the permissible limits for irrigation. No toxicity will arise by using water for permanent irrigation in all soils. However, the slight increase in Cadmium concentration in most wells should be removed first from groundwater in the study area.
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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  • 5
    Publication Date: 2018-05-20
    Description: Publication date: Available online 18 May 2018 Source: Water Science Author(s): Iikpoemugh Elo Imiete, Nadezda Viacheslovovna Alekseeva The Niger Delta region of Nigeria is faced with the problem of drinking water supply. Different methods of water purification were compared and reverse osmosis was considered a choice method for the experiment. Among the region’s brackish water reserves with heavy metal contamination, nickel and cobalt were considered. Model solutions of nickel and cobalt were prepared to mimic the brackish water contamination levels and were purified with cellulose acetate reverse osmosis membrane. Experimental results showed that purifications were more dependent on the overall salt concentrations and not on individual components.
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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  • 6
    Publication Date: 2018-05-20
    Description: Publication date: Available online 18 May 2018 Source: Water Science Author(s): Raju Thapa, Srimanta Gupta, Shirshendu Guin, Harjeet Kaur The assessment of groundwater vulnerability is essential especially in developing areas, where agriculture is the main source of the population. In the present study, four different overlay and index method, namely, DRASTIC, modified DRASTIC, pesticide DRASTIC and modified pesticide DRASTIC are implemented with a view to identifying the most appropriate method that predicts the vulnerable zone to groundwater pollution. Sensitivity analysis reveals that net recharge is the most influential parameter of the vulnerability index. Cross comparison of model output shows the highest similarity of 97% is observed between drastic and modified drastic while the maximum difference in models prediction of 49% is observed between modified drastic and pesticide drastic. Reported nitrate concentrations in groundwater are considered for validation of model-generated final output map. The prediction power of the models are assessed using success and prediction rate method and it highlights DRASTIC model as the most suitable model with 89.69% and 84.54% of the area under area under the curve (AUC) for success and prediction rate respectively. Graphical abstract
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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  • 7
    Publication Date: 2018-05-20
    Description: Publication date: Available online 18 May 2018 Source: Water Science Author(s): ElSayed ElBastamy ElSayed This study presents an evaluation of Egyptian diatomite as a low cost adsorbent for the removal of heavy metal under different conditions (pH, weight of diatomite and contact time). The adsorption of heavy metals was investigated under various pH values ranged from 2 to 8 at 25 °C. The obtained results indicate that at low pH (2–4), the removal efficiency of diatomite for heavy metal increased slightly as the pH, adsorbent dose and contact time increased, while at pH > 4, the percentage of metal ions adsorbed decreased with increasing pH due to precipitation of heavy metals. At pH equal 4, with using 2 g L −1 of diatomite and 75 min as contact time, the maximum adsorption capacity of diatomite was obtained. The high adsorption capacity of diatomite makes it a suitable low cost material for the removal of different heavy metals from aqueous solutions.
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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  • 8
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    Publication Date: 2018-05-20
    Description: Publication date: Available online 18 May 2018 Source: Water Science Author(s): Yasser M. Shawky In the context of implementing and modifying pump stations, this study was commenced with the purpose of enhancing the flow pattern at their upstream. For that, a hydraulic study using fixed bed physical model was carried out to investigate the non-uniformity of flow distribution due to the formation of separation zone upstream of Lateral Pump Station (New Hafeer Pump Station). A new approach was investigated in the model to reduce the separation zones activity without any adverse impacts on the operation process. The approach is a combination of installing series of small Spur Dykes and Humps at the drain where the station is located. Four complementary modifications using the new approach were proposed and simulated. The results indicated the effectiveness of the investigated approach in eliminating the separation zone and hence improving the approach flow at the station entrance which makes the station units to withdraw regular and equal discharges.
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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  • 9
    Publication Date: 2018-05-20
    Description: Publication date: Available online 18 May 2018 Source: Water Science Author(s): Mohie eldin Mohamed Afify Elmashad Irrigation projects in Egypt have been facing tremendous challenges, mostly is the scarcity of irrigation water. The current research presents the effect of different cohesive admixture on the conductivity of siliceous sand in general and its other geotechnical properties. Two different types of conventional swelling clay from (Toshka, 6th of October) as well as bentonite were used to construct the irrigation canals and embankment. The results indicated that increase in the plasticity properties of the treated soil also decrease the permeability and infiltration. Moreover, the dry density of 2.08 t/m 3 was obtained from sand and 20% 6th of October mixture, also the CBR of 31.20% were obtained from sand and 8% 6th of October mixture. Increasing the bentonite ratio increases the cohesion and decreasing the permeability. The swelling ratios of sand 6th of October Clay mixture is equal to 0.28%, and the fictitious stress at which the swelling ratio is nil, is equal to 16 kPa.
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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  • 10
    Publication Date: 2018-05-20
    Description: Publication date: Available online 18 May 2018 Source: Water Science Author(s): Kayla Ouellette, Kamal A. Alsharif, John C. Capece, Hannah Torres Lands in the Everglades Agricultural Area (EAA) can be used for increased water storage in order to relieve coastal estuaries of excess runoff in the rainy season. The goals of this study were: (1) to quantify the environmental and economic tradeoffs of different water storage scenarios using water tolerant sugarcane cultivars; and (2) to quantify the amount of water storage possible in the EAA under different water storage scenarios. A mathematical model was developed to calculate soil depth, soil subsidence, depth to the water table, and water storage for three different sugarcane cultivars with different water tolerances. The results showed raising water tables on farmlands did have the environmental benefits of reduced soil subsidence, extended farm life and increased years of water storage. In addition, raising water tables in the EAA to increase water storage is overall more costly, but yearly costs are very low. Therefore, water storage on farmlands is an affordable interim method of water storage.
    Electronic ISSN: 1110-4929
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Elsevier
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