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Author Baptista, V.S.G.; Coelho, V.H.R.; Bertrand, G.F.; Silva, G.B.L. da; Caicedo, N.O.L.; Montenegro, S.M.G.L.; Stefan, C.; Glass, J.; Heim, R.; Conrad, A.; Almeida, C. das N.
Title Rooftop water harvesting for managed aquifer recharge and flood mitigation in tropical cities: Towards a strategy of co-benefit evaluations in João Pessoa, northeast Brazil Type Journal Article
Year 2023 Publication Journal of Environmental Management Abbreviated Journal
Volume 342 Issue Pages 118034
Keywords Flood control, Groundwater, Injection well, Stormwater management, Urban drainage, Aquifer storage and recovery
Abstract (up) Intense urbanisation in many coastal areas has led to intensification of groundwater consumption, while reducing permeable areas and increasing the frequency and magnitude of flooding. Among the potential strategies to compensate for these adverse effects, which are expected to become worse as a result of climate change, rooftop rainwater harvesting (RWH) in combination with managed aquifer recharge (MAR), may be indicated. This work investigated the performance of different configurations of such a system, tested as a twofold sustainable stormwater and domestic water management tool in a tropical metropole (João Pessoa, Brazil). This area located over a sedimentary aquifer system illustrates the water security challenges of densely urbanised areas in southern cities. To that end, several configurations of rooftop catchments and storage volumes were evaluated, by simulating a MAR-RWH system connected to the regional unconfined aquifer (Barreiras Formation) through a 6″ diameter injection well. Rainfall-runoff-recharge processes and water balances were simulated using monitored high-temporal resolution rainfall data. The results showed that catchments ranging from 180 to 810 m2, connected to tanks from 0.5 to 30.0 m³, are the optimal solutions in terms of efficient rainwater retention and peak flow reduction. These solutions provided mean annual estimates of aquifer recharge between 57 and 255 m³/yr from 2004 to 2019. The results of this study highlight the opportunity for MAR schemes to reconcile stormwater management and water supply goals.
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ISSN 0301-4797 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Baptista2023118034 Serial 237
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Author Zeng, S.; Song, J.; Sun, B.; Wang, F.; Ye, W.; Shen, Y.; Li, H.
Title Seepage characteristics of the leaching solution during in situ leaching of uranium Type Journal Article
Year 2023 Publication Nuclear Engineering and Technology Abbreviated Journal
Volume 55 Issue 2 Pages 566-574
Keywords In situ leaching, Leaching solution viscosity, Seepage characteristics, Seepage pressure, Uranium-bearing sandstone
Abstract (up) Investigating the seepage characteristics of the leaching solution in the ore-bearing layer during the in situ leaching process can be useful for designing the process parameters for the uranium mining well. We prepared leaching solutions of four different viscosities and conducted experiments using a self-developed multifunctional uranium ore seepage test device. The effects of different viscosities of leaching solutions on the seepage characteristics of uranium-bearing sandstones were examined using seepage mechanics, physicochemical seepage theory, and dissolution erosion mechanism. Results indicated that while the seepage characteristics of various viscosities of leaching solutions were the same in rock samples with similar internal pore architectures, there were regular differences between the saturated and the unsaturated stages. In addition, the time required for the specimen to reach saturation varied with the viscosity of the leaching solution. The higher the viscosity of the solution, the slower the seepage flow from the unsaturated stage to the saturated stage. Furthermore, during the saturation stage, the seepage pressure of a leaching solution with a high viscosity was greater than that of a leaching solution with a low viscosity. However, the permeability coefficient of the high viscosity leaching solution was less than that of a low viscosity leaching solution.
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ISSN 1738-5733 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ zeng_seepage_2023 Serial 211
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Author Wang, W.; Liang, X.; Niu, Q.; Wang, Q.; Zhuo, J.; Su, X.; Zhou, G.; Zhao, L.; Yuan, W.; Chang, J.; Zheng, Y.; Pan, J.; Wang, Z.; Ji, Z.
Title Reformability evaluation of blasting-enhanced permeability in in situ leaching mining of low-permeability sandstone-type uranium deposits Type Journal Article
Year 2023 Publication Nuclear Engineering and Technology Abbreviated Journal
Volume 55 Issue 8 Pages 2773-2784
Keywords Analytic hierarchy process-entropy method, Fuzzy mathematics method, Mechanical property, Mineral composition, Pore structure, Split Hopkinson pressure bar
Abstract (up) It is essential to evaluate the blasting-enhanced permeability (BEP) feasibility of a low-permeability sandstone-type uranium deposit. In this work, the mineral composition, reservoir physical properties and rock mechanical properties of samples from sandstone-type uranium deposits were first measured. Then, the reformability evaluation method was established by the analytic hierarchy process-entropy weight method (AHP-EWM) and the fuzzy mathematics method. Finally, evaluation results were verified by the split Hopkinson Pressure Bar (SHPB) experiment and permeability test. Results show that medium sandstone, argillaceous sandstone and siltstone exhibit excellent reformability, followed by coarse sandstone and fine sandstone, while the reformability of sandy mudstone is poor and is not able to accept BEP reservoir stimulation. The permeability improvement and the distribution of damage fractures before and after the SHPB experiment confirm the correctness of evaluation results. This research provides a reformability evaluation method for the BEP of the low-permeability sandstone-type uranium deposit, which contributes to the selection of the appropriate regional and stratigraphic horizon of the BEP and the enhanced ISL of the low-permeability sandstone-type uranium deposit.
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ISSN 1738-5733 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ wang_reformability_2023 Serial 194
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Author Liu, Z.; Tan, K.; Li, C.; Li, Y.; Zhang, C.; Song, J.; Liu, L.
Title Geochemical and S isotopic studies of pollutant evolution in groundwater after acid in situ leaching in a uranium mine area in Xinjiang Type Journal Article
Year 2023 Publication Nuclear Engineering and Technology Abbreviated Journal
Volume 55 Issue 4 Pages 1476-1484
Keywords Acid in situ leaching of uranium, Pollution evolution, Sulfate elimination, Sulfur isotopes analysis
Abstract (up) Laboratory experiments and point monitoring of reservoir sediments have proven that stable sulfate reduction (SSR) can lower the concentrations of toxic metals and sulfate in acidic groundwater for a long time. Here, we hypothesize that SSR occurred during in situ leaching after uranium mining, which can impact the fate of acid groundwater in an entire region. To test this, we applied a sulfur isotope fractionation method to analyze the mechanism for natural attenuation of contaminated groundwater produced by acid in situ leaching of uranium (Xinjiang, China). The results showed that δ34S increased over time after the cessation of uranium mining, and natural attenuation caused considerable, area-scale immobilization of sulfur corresponding to retention levels of 5.3%–48.3% while simultaneously decreasing the concentration of uranium. Isotopic evidence for SSR in the area, together with evidence for changes of pollutant concentrations, suggest that area-scale SSR is most likely also important at other acid mining sites for uranium, where retention of acid groundwater may be strengthened through natural attenuation. To recapitulate, the sulfur isotope fractionation method constitutes a relatively accurate tool for quantification of spatiotemporal trends for groundwater during migration and transformation resulting from acid in situ leaching of uranium in northern China.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1738-5733 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ liu_geochemical_2023 Serial 192
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Author Zhao, Y.; Li, X.; Lei, L.; Chen, L.; Luo, Z.
Title Permeability evolution mechanism and the optimum permeability determination of uranium leaching from low-permeability sandstone treated with low-frequency vibration Type Journal Article
Year 2023 Publication Journal of Rock Mechanics and Geotechnical Engineering Abbreviated Journal
Volume 15 Issue 10 Pages 2597-2610
Keywords Chemical reactive rate, Low-frequency vibration, Low-permeability sandstone, Optimum permeability, Permeability evolution mechanism, Uranium migration
Abstract (up) Low-frequency vibrations can effectively improve natural sandstone permeability, and higher vibration frequency is associated with larger permeability. However, the optimum permeability and permeability evolution mechanism for uranium leaching and the relationship between permeability and the change of chemical reactive rate affecting uranium leaching have not been determined. To solve the above problems, in this study, identical homogeneous sandstone samples were selected to simulate low-permeability sandstone; a permeability evolution model considering the combined action of vibration stress, pore water pressure, water flow impact force, and chemical erosion was established; and vibration leaching experiments were performed to test the model accuracy. Both the permeability and chemical reactions were found to simultaneously restrict U6+ leaching, and the vibration treatment increased the permeability, causing the U6+ leaching reaction to no longer be diffusion-constrained but to be primarily controlled by the reaction rate. Changes of the model calculation parameters were further analyzed to determine the permeability evolution mechanism under the influence of vibration and chemical erosion, to prove the correctness of the mechanism according to the experimental results, and to develop a new method for determining the optimum permeability in uranium leaching. The uranium leaching was found to primarily follow a process consisting of (1) a permeability control stage, (2) achieving the optimum permeability, (3) a chemical reactive rate control stage, and (4) a channel flow stage. The resolution of these problems is of great significance for facilitating the application and promotion of low-frequency vibration in the CO2 + O2 leaching process.
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ISSN 1674-7755 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ zhao_permeability_2023 Serial 198
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