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Author Röttcher, K.
Title Type Book Chapter
Year 2018 Publication Risikomanagement und Nachhaltigkeit in der Wasserwirtschaft: Erfolgreiche Navigation durch die Komplexität und Dynamik des Risikos Abbreviated Journal
Volume Issue Pages 165-174
Keywords
Abstract (up) Im vorliegenden Beitrag werden beispielhaft unterschiedliche Ansätze des Risikomanagements und das Verständnis von Nachhaltigkeit in der Wasserwirtschaft dargelegt. Die Darstellung richtet sich insbesondere an Leser aus anderen Fachdisziplinen, wie das Rechts- und Finanzwesen, den Fahrzeug- und Maschinenbau oder auch die sozialen Berufe. Die Zusammenhänge werden überblicksartig mit einzelnen konkreten Beispielen dargestellt mit dem Fokus auf die grundsätzlichen Denk- und Vorgehensweisen.
Address
Corporate Author Thesis
Publisher Springer Fachmedien Wiesbaden Place of Publication Wiesbaden Editor Michalke, A.; Rambke, M.; Zeranski, S.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 978-3-658-19684-4 Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Röttcher2018 Serial 90
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Author Brook, G.A.; Marais, E.; Srivastava, P.; Jordan, T.
Title Timing of lake-level changes in Etosha Pan, Namibia, since the middle Holocene from OSL ages of relict shorelines in the Okondeka region Type Journal Article
Year 2007 Publication Quaternary International Abbreviated Journal
Volume 175 Issue 1 Pages 29-40
Keywords
Abstract (up) In 2003 examination of aerial photographs revealed a series of previously unknown relict shorelines on the arcuate ridge, possibly a clay lunette dune, that marks the western boundary of Etosha Pan in Namibia. The shorelines are 120–600m wide and the most prominent extend for tens of km around the lunette dune. The shorelines were examined on the ground in 2004 and an attempt was made to date the three lowest levels at ca. 5, 2.5 and 1m above the present pan surface. The OSL ages obtained indicate higher and more prolonged lake conditions than today at ca. 6.4, 4.0 and 2.1ka with the youngest shoreline sediments resting on an ancient pan surface dating to ca. 13ka. The evidence indicates dry conditions in the pan at ca. 13ka, wetter conditions and higher lake levels in the middle Holocene followed by a decline in lake levels to the present. Periods of inundation were of sufficient duration to produce shorelines at the southwestern end of the pan due to the prevailing northeasterly winds that would have maximized wave action along this section of the pan margin. The Etosha findings, together with other regional paleoclimate data, suggest four periods of increased wetness in SW Africa during the Holocene at 7–5, 4.5–3.5, 2.5–1.7 and ca. 1.0ka. There is widespread evidence for the oldest of these periods suggesting that it was a prominent and widespread interval of wetness. Prior to ca. 8.0ka the climate may have been drier than today.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1040-6182 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ brook_timing_2007 Serial 97
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Author Boumaiza, L.; Ammar, S.B.; Chesnaux, R.; Stotler, R.L.; Mayer, B.; Huneau, F.; Johannesson, K.H.; Levison, J.; Knöller, K.; Stumpp, C.
Title Nitrate sources and transformation processes in groundwater of a coastal area experiencing various environmental stressors Type Journal Article
Year 2023 Publication Journal of Environmental Management Abbreviated Journal
Volume 345 Issue Pages 118803
Keywords Aquifer, Denitrification, MixSIAR, Nitrate, Nitrification, Stable isotopes
Abstract (up) In coastal salinized groundwater systems, contamination from various nitrate (NO3) inputs combined with complex hydrogeochemical processes make it difficult to distinguish NO3 sources and identify potential NO3 transformtation processes. Effective field-based NO3 studies in coastal areas are needed to improve the understanding of NO3 contamination dynamics in groundwater of such complex coastal systems. This study focuses on a typical Mediterranean coastal agricultural area, located in Tunisia, experiencing substantial NO3 contamination from multiple anthropogenic sources. Here, multiple isotopic tracers (δ18OH2O, δ2HH2O, δ15NNO3, δ18ONO3, and δ11B) combined with a Bayesian isotope MixSIAR model are used (i) to identify the major NO3 sources and their contributions, and (ii) to describe the potential NO3 transformation processes. The measured NO3 concentrations in groundwater are above the natural baseline threshold, suggesting anthropogenic influence. The measured isotopic composition of NO3 indicates that manure, soil organic matter, and sewage are the potential sources of NO3, while δ11B values constrain the NO3 contamination to manure; a finding that is supported by the results of MixSIAR model revealing that manure-derived NO3 dominates over other likely sources. Nitrate derived from manure in the study area is attributed to organic fertilizers used to promote crop growth, and livestock that deposit manure directly on the ground surface. Evidence for ongoing denitrification in groundwaters of the study area is supported by an enrichment in both 15N and 18O in the remaining NO3, although isotopic mass balances between the measured and the theoretical δ18ONO3 values also suggest the occurrence of nitrification. The simultaneous occurrence of these biogeochemical processes with heterogeneous distribution across the study area reflect the complexity of interactions within the investigated coastal aquifer. The multiple isotopic tracer approach used here can identify the effect of multiple NO3 anthropogenic activities in coastal environments, which is fundamental for sustainable groundwater resources management.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0301-4797 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ boumaiza_nitrate_2023 Serial 170
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Author Robin, V.; Beaufort, D.; Tertre, E.; Reinholdt, M.; Fromaget, M.; Forestier, S.; Boissezon, H. de; Descostes, M.
Title Fate of dioctahedral smectites in uranium roll front deposits exploited by acidic In Situ Recovery (ISR) solutions Type Journal Article
Year 2020 Publication Applied Clay Science Abbreviated Journal
Volume 187 Issue Pages 105484
Keywords Dissolution, In situ recovery, Ion exchange, Post mining, Remediation, Smectite
Abstract (up) In Situ Recovery (ISR) is the most important process of uranium production in the world (50%). It consists of an injection of a leaching solution into a permeable mineralized aquifer (sandstone), pumping of the solution after dissolution of the ore minerals and recovery of the uranium from the pregnant solution in a surface plant. In this context, the fate of swelling clay minerals such as smectites is of main importance due to their role in the mobility of cationic elements by diverse geochemical processes such as ion-exchange reactions or dissolution. The present study details analysis of dioctahedral smectites before and after in-situ leaching by acidic (H2SO4) ISR solutions. Samples were collected from two sedimentary basins hosting some of the main uranium roll front deposits exploited by acidic ISR (Tortkuduk deposit, Shu-Saryssu basin, Kazakhstan, and Dulaan Uul and Zoovch Ovoo deposits, Sainshand basin, Mongolia). Scanning Electron Microscope and X-Ray Diffraction analysis revealed that dioctahedral smectite is a ubiquitous mineral in all analyzed samples, before and after acidification, and revealed a difference of crystal chemistry of the smectites between deposits of Kazakhstan (beidellite type) and Mongolia (montmorillonite type). Chemical analysis and semi-quantification of the smectites before and after acidification also revealed a difference in chemical reactivity, with a higher dissolution of montmorillonite layers compared to beidellite ones, and the importance of ion-exchange reactions. These findings are consistent with literature data obtained on model systems. The persistence of dioctahedral smectites after several years of acidification is crucial for the understanding of geochemical processes during uranium production or remediation of the aquifers. Finally, based on the analysis of samples from U-deposits hosted in both sedimentary basins, a schematic model of the impact of acid solutions on dioctahedral smectite was proposed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-1317 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ robin_fate_2020 Serial 179
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Author Schwiede, M.; Duijnisveld, W.H.M.; Böttcher, J.
Title Investigation of processes leading to nitrate enrichment in soils in the Kalahari Region, Botswana Type Journal Article
Year 2005 Publication Physics and Chemistry of the Earth, Parts A/B/C Abbreviated Journal
Volume 30 Issue 11 Pages 712-716
Keywords Nitrate, Arenosol soils, Semi-arid, Kalahari, Cattle, Chloride, Travel time
Abstract (up) In Southern Africa elevated nitrate concentrations are observed in mostly uninhabited semi-arid areas. In the Kalahari of Botswana groundwater locally exhibits concentrations up to 600mg/l. It is assumed, that nitrate found in the groundwater originates mainly from nitrogen input and transformations in the soils. Our investigations in the Kalahari between Serowe and Orapa show that cattle raising is an important source for enhanced nitrate concentrations in the soils (Arenosols). But also in termite mounds very high nitrate stocks were found, and under natural vegetation (acacia trees and shrubs) nitrate concentrations were mostly unexpectedly high. This nitrate enrichment in the soils poses a serious threat to the groundwater quality. However, calculated soil water age distributions in the unsaturated zone clearly show that today’s nitrate pollution of the groundwater below the investigation area could originate from natural sources, but cannot be caused by the current land use for cattle raising.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1474-7065 ISBN Medium
Area Expedition Conference
Notes Integrated Water Resources Management (IWRM) and the Millennium Development Goals: Managing Water for Peace and Prosperity Approved no
Call Number THL @ christoph.kuells @ Schwiede2005712 Serial 276
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Author Hu, K.; Wang, Q.; Tao, G.; Wang, A.; Ding, D.
Title Experimental Study on Restoration of Polluted Groundwater from in Situ Leaching Uranium Mining with Sulfate Reducing Bacteria and ZVI-SRB Type Journal Article
Year 2011 Publication Procedia Earth and Planetary Science Abbreviated Journal
Volume 2 Issue Pages 150-155
Keywords In situ leaching of uranium, nitrate radical, sulfate radical, Sulfate-Reducing Bacteria (SRB), Zero Valent Iron (ZVI)
Abstract (up) In the case of in situ leaching of uranium, the primitive geochemical environment for groundwater is changed since leachant is injected into the water beaving uranium deposit. This increases the concentration of uranium and results in the groundwater contamination.Microbial reduction technology by Sulfate reducing bacteria and Zero Valent Iron were employed to treat uranium wastewater. The experiments were conducted to evaluate the influence of anion (sulfate and nitrate) on dealing with uranium wastewater. Experimental results show that the utilization of both SRB system and ZVI – SRB system to process uranium wastewater is affected by sulfate ion and nitrate ion. As the concentration of sulfate radical is lower than 4000mg/L, sulfate-reducing bacteria has no influence on precipitated uranium. However, as the concentration of sulfate is more than 6,000mg/L, uranium removal rate decreases significantly, from 80% to 14.1%. When adding sulfate radical on ZVI – SRB system to process uranium wastewater, its uranium removal rate is higher than SRB system. Low concentration of nitrate contributes to reduction metabolism of SRB. High concentration of nitrate inhibits the growth and metabolism of SRB and affects the treatment efficiency of uranium wastewater. When the concentration of nitrate reaches 1500mg/L, uranium removal rate is less than 0.1%. Nevertheless, as the concentration of nitrate is lower than 1000mg/L, uranium removal rate could reach more than 75%. As existence of nitrate radical, uranium removal rate of SRB by adding ZVI is higher than that without adding.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1878-5220 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ hu_experimental_2011 Serial 202
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Author Patel, D.; Pamidimukkala, P.; Chakraborty, D.
Title Groundwater quality evaluation of Narmada district, Gujarat using principal component analysis Type Journal Article
Year 2024 Publication Groundwater for Sustainable Development Abbreviated Journal
Volume 24 Issue Pages 101050
Keywords Fluoride, Groundwater quality index, Principal component analysis, Uranium
Abstract (up) In the present study, the ground water quality parameters were monitored during pre- and post-monsoon seasons across Narmada district, Gujarat, India. Monitoring was done in 89 drinking water samples collected by grid sampling method from the study area. Uranium and fluoride were analyzed along with associated parameters such as pH, dissolved oxygen, Cl−, NO3−, F−, SO42−, total alkalinity, total dissolved solids and hardness. In 4% samples the fluoride content was found to be above WHO permissible limits of 1.5 mg/L (2.36 mg/L in Undaimandava, 1.55 mg/L in Shira, 3.04 mg/L in Fatehpur and 1.83 mg/L in Dholivav) during pre-monsoon season (PRM) and 4.74 mg/L, 2.41 mg/L, 2.34 mg/L and 3.99 mg/L respectively in Bantawadi, Shira, Undai Mandava and Fatepur villages during post-monsoon (POM). The uranium level was within WHO limits in both POM and PRM seasons. The quality of the water was evaluated by Principal Component and Pearson Correlation statistical analysis techniques. The PRM and POM correlation study indicated a strong correlation of TDS with EC, Chloride, total alkalinity and bicarbonate and U while moderately strong correlation of TDS with fluoride were observed indicating that chloride, total alkalinity, bicarbonate, U and fluoride contributed to TDS and EC. Principal component analysis was applied for 14 variables, from which 3 factors were extracted during PRM and POM seasons. The extracted components, contributed 84.391% and 83.315%, to variation during PRM and POM seasons respectively. The study indicated that the analyzed water samples in Narmada district were safe for drinking purpose. However, Tilakwada tehsil groundwater was observed to be unsustainable for drinking, without further water treatment, but was appropriate for agricultural purposes. The study will help the residents of the district to understand the present water quality status and will also help in future management to protect the ground water of Narmada district.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2352-801x ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ patel_groundwater_2024 Serial 148
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Author Tisherman, R.A.; Rossi, R.J.; Shonkoff, S.B.C.; DiGiulio, D.C.
Title Groundwater uranium contamination from produced water disposal to unlined ponds in the San Joaquin Valley Type Journal Article
Year 2023 Publication Science of The Total Environment Abbreviated Journal
Volume 904 Issue Pages 166937
Keywords Groundwater, Oil & gas, Produced water, San Joaquin Valley, Uranium
Abstract (up) In the southern San Joaquin Valley (SJV) of California, an agriculturally productive region that relies on groundwater for irrigation and domestic water supply, the infiltration of produced water from oil reservoirs is known to impact groundwater due to percolation from unlined disposal ponds. However, previously documented impacts almost exclusively focus on salinity, while contaminant loadings commonly associated with produced water (e.g., radionuclides) are poorly constrained. For example, the infiltration of bicarbonate-rich produced waters can react with sediment-bound uranium (U), leading to U mobilization and subsequent transport to nearby groundwater. Specifically, produced water infiltration poses a particular concern for SJV groundwater, as valley-fill sediments are well documented to be enriched in geogenic, reduced U. Here, we analyzed monitoring well data from two SJV produced water pond facilities to characterize U mobilization and subsequent groundwater contamination. Groundwater wells installed within 2 km of the facilities contained produced water and elevated levels of uranium. There are \textgreater400 produced water disposal pond facilities in the southern SJV. If our observations occur at even a fraction of these facilities, there is the potential for widespread U contamination in the groundwaters of one of the most productive agricultural regions in the world.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0048-9697 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ tisherman_groundwater_2023 Serial 159
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Author Naghedifar, S.M.; Ziaei, A.N.; Naghedifar, S.A.; Ansari, H.
Title A new model for simulation of collection and conveyance sections of Qanat Type Journal Article
Year 2020 Publication Journal of Hydrology Abbreviated Journal
Volume 590 Issue Pages 125218
Keywords Richards’ equation, Saint-Venant equation, Numerical modeling, Qanat-aquifer system
Abstract (up) In this paper, a new numerical model has been developed for simulation of Qanat-aquifer system. This model employs quasi-3D mixed-form of Richards’ equation and 1D fully-hydrodynamic form of Saint-Venant equations to simulate subsurface and overland flow, respectively. In order to handle non-orthogonal grids, subsurface flow module benefits from coordinate transformation technique. Using the above-mentioned governing equations, the presented model is able to simulate water flow inside both collection and conveyance sections of the gallery as well as dynamics of groundwater and vadose zone from impermeable bed rock to the soil-air interface. Since measured data corresponding to the hydraulics of Qanats is scarce, the overland and subsurface modules have been validated with analytical, numerical and experimental benchmarks in the literature. Subsequently, the model was employed to simulate ten different hypothetical aquifer-Qanat systems with different properties including the depth of groundwater aquifer, roughness of the gallery and saturated hydraulic conductivity of the gallery-aquifer boundary and the influence of each the parameters was monitored on the outflow rate at the appearance point of each Qanat. Furthermore, the advance of water inside two initially dry galleries were simulated at different time levels up to steady state. Eventually, the streamlines have been shown at the steady state for two Qanat-aquifer systems. Although, the presented study sheds light on some aspects of Qanat-aquifer hydraulics, the validation of the presented model with in-lab or on-field data remains ongoing for the future researches.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-1694 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Naghedifar2020125218 Serial 254
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Author Shayakhmetov, N.M.; Alibayeva, K.A.; Kaltayev, A.; Panfilov, I.
Title Enhancing uranium in-situ leaching efficiency through the well reverse technique: A study of the effects of reversal time on production efficiency and cost Type Journal Article
Year 2023 Publication Hydrometallurgy Abbreviated Journal
Volume 219 Issue Pages 106086
Keywords Economic evaluation, Hydrodynamic enhancement of mineral production, In-situ leaching, Mineral recovery, Optimal reversal time, Well reversing technique
Abstract (up) In this study, the application of the Well Reversal Technique (WRT) and the impact of reversal time on the efficiency of uranium mining via In-Situ Leaching (ISL) were investigated. A prevalent issue in ISL mineral extraction is the formation of stagnant zones caused by limited access of the lixiviant, which leads to increased operating expenditures. The WRT, which involves altering the function of some wells from injection to production or vice versa, is a potential solution to this problem. The efficiency of WRT is heavily dependent on the well pattern and reversal time. Two commonly used well patterns in ISL are the 9-spot (row arrangement) and 7-spot (hexagonal arrangement). The objective of this study was to determine the optimal reversal time for a 9-spot well pattern through mathematical modeling of hydrodynamic and physico-chemical processes and subsequent economic assessment. A mathematical model of uranium extraction processes was developed using the principles of mass conservation, Darcy’s, and mass action laws. The results obtained for a 9-spot well pattern without reversal, with two reversal options, and a 7-spot scheme were analyzed comparatively. The 7-spot scheme without reversal was found to be the most effective of the options examined. The application of WRT on a 9-spot well pattern allows to enhance production efficiency to a level comparable to that of a 7-spot well pattern. Additionally, the effect of reversal time on recovery was studied based on two well reversal options. The results from calculation revealed that the optimal scenario was when the well reversal is conducted immediately after the time point at which the average concentration of the pregnant solution in the production wells reaches its peak value. The overall efficiency of WRT application was determined through economic calculations of capital (CAPEX) and operating (OPEX) expenditures. Based on economic calculations, it was determined that the utilization of WRT results in a 3–18% increase in mineral production efficiency for a 9-point scheme, depending on the chosen reversal method.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-386x ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ shayakhmetov_enhancing_2023 Serial 203
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