References of "Orban, Philippe"
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See detailParametric assessment of hydrochemical changes associated to underground pumped hydropower storage
Pujades, Estanislao; Jurado, Anna; Orban, Philippe ULiege et al

in Science of the Total Environment (2019), 659

Underground pumped hydropower storage (UPHS) using abandoned mines is an alternative to store and produce electricity in flat regions. Excess of electricity is stored in form of potential energy by ... [more ▼]

Underground pumped hydropower storage (UPHS) using abandoned mines is an alternative to store and produce electricity in flat regions. Excess of electricity is stored in form of potential energy by pumping mine water to a surface reservoir. When the demand of electricity increases, water is discharged into the mine (i.e., underground reservoir) through turbines producing electricity. During the complete operational process of UPHS plants, hydrochemical characteristics of water evolve continuously to be in equilibrium successively with the atmosphere (in the surface reservoir) and the surrounding porousmedium (in the underground reservoir). It may lead to precipitation and/or dissolution of minerals and their associated consequences, such as pH variations. Induced hydrochemical changes may have an impact on the environment and/or the efficiency (e.g., corrosions and incrustations affect facilities) of UPHS plants. The nature of the hydrochemical changes is controlled by the specific chemical characteristics of the surrounding porous medium. However, the magnitude of the changes also depends on other variables, such as hydraulic parameters. The role of these parameters is established to define screening criteria and improve the selection procedure of abandonedmines for constructing UPHS plants. This work evaluates the role of the main hydrogeological factors for three different chemical composition of the porous medium. Results are obtained by means of numerical reactive transport modeling. Potential impacts on the environment (mainly on groundwater and surface water bodies) and on the efficiency of the UPHS plants vary considerably from a hydraulic parameter to another showing the need for a detailed characterization before choosing locations of future UPHS plants. [less ▲]

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See detailDynamics of greenhouse gases in groundwater: hydrogeological and hydrogeochemical controls
Nikolenko, Olha ULiege; Orban, Philippe ULiege; Jurado, Anna et al

in Applied Geochemistry (2019), 105

In this study the variability of greenhouse gases (GHGs) concentrations along lateral and vertical dimensions of the chalk aquifer located in the eastern part of Belgium was examined in order to ... [more ▼]

In this study the variability of greenhouse gases (GHGs) concentrations along lateral and vertical dimensions of the chalk aquifer located in the eastern part of Belgium was examined in order to understand its dependence on hydrogeological and hydrogeochemical conditions. Groundwater samples from 29 wells/piezometers were analyzed for concentrations of nitrous oxide (N2O), carbon dioxide (CO2), methane (CH4), major and minor elements and stable isotopes of nitrate (NO3−), nitrous oxide (N2O), sulfate (SO42−) and boron (B). For lateral investigations, four zones with different environmental settings were identified (southern, central, north-eastern and northern). Groundwater was oversaturated with GHGs with respect to its equilibrium concentrations with the atmosphere in all zones, except the northern one, undersaturated in N2O (0.07 ± 0.08 μgN/L vs. 0.3 μgN/L). Vertical dimension studies showed the decrease in CO2 concentration and significant changes in both isotope signatures and concentration of N2O with depth. The production of N2O could be attributed to a combination of nitrification and denitrification processes occurring at different depths. CO2 concentration is controlled by the process of dissolution of carbonate minerals which constitute aquifer geology. CH4 is produced due to methanogenesis in deeper parts of the aquifer, though its thermogenic origin is also possible. Differences in hydrogeochemical settings and changing intensity of biogeochemical processes across the area and with depth have considerable effect on GHGs concentrations. Thus, before estimating GHGs fluxes at the groundwater–river interface insights obtained from larger-scale investigations are required in order to identify the representative spatial zones which govern GHGs emissions. [less ▲]

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See detailTowards a subsurface predictive-model environment to simulate aquifer thermal energy storage for demand-side management applications
Robert, Tanguy ULiege; Hermans, Thomas ULiege; Lesparre, Nolwenn et al

in Proceedings of SSB 2018, 10th International Conference on System Simulation in Buildings (2018, December 12)

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See detailGeothermal use of old mines: hydrogeological challenges for predicting efficiency and impacts
Vopat, Olivier; Orban, Philippe ULiege; Brouyère, Serge ULiege et al

Conference (2018, September 14)

Groundwater in flooded abandoned mines could be used for geothermal purposes using heat-pumps and an open loop involving pumping and re-injection. Logically, warm water is usually expected to be pumped ... [more ▼]

Groundwater in flooded abandoned mines could be used for geothermal purposes using heat-pumps and an open loop involving pumping and re-injection. Logically, warm water is usually expected to be pumped (or injected) in the deep parts of the open network, and cold water is expected to be re-injected (or pumped) in the shallower parts. However, the feasibility and the durability of future ‘Ground Source Heat Pump system’ (GSHP) must be studied through a deep characterization of the subsoil but also using numerical models able to simulate groundwater flow and heat transfer in these complex geological environments. Depending on the type of abandoned mine, the true geometry of the interconnected network of open galleries and shafts can indeed be highly complex. A high-velocity water flow is expected in this type of network, while low-velocity groundwater flow occurs in less permeable fractured and porous rock massif. The SUFT3D code that allows combining in a single model, and in a fully interacting way, linear or distributed reservoirs to model groundwater flows in mine galleries and classical groundwater flow in the variably saturated equivalent porous surrounding media is developed to model heat transfer using the similarities existing between solute and heat transfer equations. The code is then used to test on simple and synthetic case studies, the impact of the hydrogeological conditions and of technical choices on the feasibility and the durability of these geothermal systems. [less ▲]

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See detailInfluence of groundwater-surface interactions on groundwater salinity in the Senegal River Delta
Gning, Abdoul Aziz; Wheatherl, Robin; Orban, Philippe ULiege et al

Conference (2018, September 13)

The Senegal River Delta is a strategic region for the development of irrigated agriculture. However, the existence of a shallow saline aquifer, in conjunction with intensification of irrigated agriculture ... [more ▼]

The Senegal River Delta is a strategic region for the development of irrigated agriculture. However, the existence of a shallow saline aquifer, in conjunction with intensification of irrigated agriculture, has led to degradation of cultivated soils. At the end of the XXth Century, the construction of dams on the river has secured water availability throughout the year and induced a rise in surface water levels, inducing a lateral recharge of groundwater in the alluvial aquifer. Because of these major environmental changes, groundwater freshening was expected to occur. Using a combination of regional piezometric and hydrogeochemical surveys as well as local geophysical and hydrogeochemical surveys, groundwater–surface water interactions were characterized to identify the impact of artificial river management and agricultural intensification (among other rice cultivation) on the evolution of groundwater dynamics and chemistry. Results show that groundwater-surface water interactions are mainly visible near rivers where freshwater lenses have developed, with a groundwater salinity that is lower than seawater and groundwater mineralization that seems to evolve in the direction of softening through cationic exchanges related to permanent contact with fresh water. Groundwater far away from rivers and outside irrigated plots has evolved from marine water to brines under the influence of evapotranspiration. In the cultivated parcels, despite large volumes of water used for rice cultivation, groundwater does not show real softening trend. In general, mechanisms that contribute to repel salt water from the sediments correspond to a lateral flush near permanent surface water streams and not to vertical drainage and dilution with rainfall or irrigation water. It is however difficult to estimate the time required to return to more favorable conditions of groundwater salinity. [less ▲]

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See detailApsûGIS : a GIS-tool for groundwater vulnerability assessment using physical criteria
Dollé, Fabien ULiege; Thomas, Caroline ULiege; Orban, Philippe ULiege et al

Poster (2018, September 11)

The Apsû method has been developed since 2004 to produce groundwater intrinsic and specific vulnerability maps based on a quantitative description of contaminant transport processes in the subsurface. It ... [more ▼]

The Apsû method has been developed since 2004 to produce groundwater intrinsic and specific vulnerability maps based on a quantitative description of contaminant transport processes in the subsurface. It is based on the source-pathway-receptor approach, driven by two concepts: land surface dangerosity that accounts for lateral flow on land surface and infiltration and subsurface attenuation capacity. Vulnerability classes are based on physically-based criteria reflecting the sensitivity of groundwater to pollution events, namely contaminant travel time across the unsaturated zone, pollution duration, or contaminant concentration or mass recovery factors at the groundwater table. To facilitate the application of the Apsû method to case studies, GIS-based applications and interfaces have been developed to integrate geodatabases and user interfaces in the same environment software. The main geodatabase contains all the data required for the calculation of the vulnerability coefficient, such as spatial data (topography, land cover, hydrological network, meteorology, soil types…) and specific databases on contaminant properties (i.e. Koc values, degradation constants…), on hydrogeological properties of geological layers constituting the unsaturated zone flow path. Specific user interfaces have been developed to prepare and export spatial data required by the Apsû calculations. Once the groundwater vulnerability factors are calculated, another user interface is available to automatically create and customize different thematic layers related to groundwater vulnerability mapping. This integrated system makes it possible to automate numerous data formatting geoprocessing operations, and to ensure data integrity by minimizing user interactions with the data (spatial frame, data projection, link between spatial data and databases, etc.) and to focus work on the specificities of the areas studied and the interpretation of the vulnerability maps created. The objective of the communication is to describe the general organisation and operation of the GIS-based interface, illustrated with groundwater vulnerability case studies for aquifers of the Walloon Region of Belgium. [less ▲]

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See detailPredictive mapping of fluoride levels in groundwater in Central Benin (Western Africa) using a geostatistical approach
Tossou; Hermans, Thomas; Orban, Philippe ULiege et al

Conference (2018, September 11)

Groundwater of the crystalline aquifers of central Benin (Département des Collines) are characterized by elevated fluoride concentrations of up to 7 mg/L, whereas the standard recommended by WHO is 1.5 mg ... [more ▼]

Groundwater of the crystalline aquifers of central Benin (Département des Collines) are characterized by elevated fluoride concentrations of up to 7 mg/L, whereas the standard recommended by WHO is 1.5 mg/L. Consumption of these waters with high fluoride content impacts human health, the population of the region being effectively largely affected by dental fluorosis. Recent hydrogeochemical investigations on groundwater from the crystalline aquifers coupled to geochemical, petrological and mineralogical investigations on rock samples collected in the area of interest have revealed that the origin of these anomalous fluoride levels is geogenic with a strong contribution of ferromagnesian minerals, mainly biotite. Using the results obtained on collected samples, together with regional information on geology, a double cartography exercise was performed on the scale of the Department of the Hills in order to obtain (1) a map of estimation of fluoride concentrations in the groundwater by ordinary kriging and (ii) a probability map of exceeding the WHO guideline value (1.5 mg / L) of fluoride in water by Indicator Kriging. In addition to the cartography itself, the analysis of the spatial structure of the data (fluoride content of the groundwater) through the calculation of the variograms shows that there is a strong link between these and the dominant geological structures, confirming the geogenic origin of fluoride. The map produced using these geostatistical procedures will serve as a support for decision makers and resource managers to make the right choice of drinking water catchment areas to avoid, at least to minimize the risk of high levels of fluoride in abstracted groundwaters. [less ▲]

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See detailExperimental assessment and prediction of short-term aquifer thermal energy storage for energy demand-side management applications
Robert, Tanguy ULiege; Hermans, Thomas; Lesparre, Nolwenn et al

Conference (2018, September 10)

Groundwater heat pump (GWHP) systems are now widely used for space heating and cooling and domestic hot water production. On one hand, GWHP systems are considered as a renewable energy and on the other ... [more ▼]

Groundwater heat pump (GWHP) systems are now widely used for space heating and cooling and domestic hot water production. On one hand, GWHP systems are considered as a renewable energy and on the other hand, their increasing use impacts electrical grid balancing. Since the coupling of electrically-driven heating, ventilation, and air-conditioning (HVAC) systems with thermal energy storage (TES) is seen as a promising tool for demand-side management (DSM) in the low-voltage grid, experimental validation of aquifer thermal energy storage (ATES) capabilities at demand side management (DSM) frequencies (real time, intraday, interday, and interseasonal) is needed for the sector to adopt it. We demonstrated here that hourly to daily ATES can be efficient in terms of energy recovery rate and exergy whereas weekly to seasonal ATES bears the risk of lower recovery rates and presents almost always low exergy. Moreover, energy recovery rates are improved with the increasing use of storage and recovery cycles. To formulate this demonstration, we emulated the operating conditions of GWHP systems with ATES in several well-characterized experimental pilot sites in Wallonia. The standardized experiment we used to estimate the different hydrodynamic parameters and energy recovery at the pilot sites was based on push/pull tests with the injection of heated water, its storage for different DSM periods, and finally its recovery. Fluxes were either measured in-situ by means of the finite volume point dilution method or estimated with the local hydraulic conductivity and gradient. We report here a direct relationship between the energy recovery rate and natural groundwater fluxes. [less ▲]

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See detailDynamics of greenhouse gases in the aquifers of two agricultural catchments of Belgium
Jurado, Anna; Nikolenko, Olha ULiege; Orban, Philippe ULiege et al

Conference (2018, September 10)

Greenhouse gases (GHGs) are an environmental problem because their concentrations in the atmosphere are continuously increasing. Agricultural practices represented up to one third of anthropogenic ... [more ▼]

Greenhouse gases (GHGs) are an environmental problem because their concentrations in the atmosphere are continuously increasing. Agricultural practices represented up to one third of anthropogenic emissions of GHGs such as nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2), which all contribute to climate change and N2O to stratospheric ozone destruction. This study presents recent case studies in two different agricultural areas of the Walloon Region (Belgium). To this end, the dynamics of CO2, CH4 and N2O were studied in the aquifers of the Triffoy and Geer catchments. In order to get an insight into GHGs production/consumption processes, the results of the stable isotope analyses of NO3-, N2O, SO42-, B, DOC and 3H along with the hydrogeochemical data were used. Our study attempts to acquire additional evidence about (1) the processes that consume and produce GHGs in groundwater in these two catchments (2) the spatial variability of N2O along the lateral and vertical dimensions of the Geer aquifers and (3) the dynamics of GHGs in the river-groundwater interface in the Triffoy catchment. Results indicate that groundwater is oversaturated in N2O and CO2 with respect to atmospheric equilibrium but only marginally for CH4, suggesting that groundwater can be a source of these GHGs to the atmosphere. Nitrification and nitrifier-denitrification seems to be the main process for the accumulation of N2O in groundwater of the two catchments and the oxic conditions prevailing in the aquifers are not prone to the accumulation of CH4. Groundwater is probably an important source of N2O and CO2 into the river but when the measures are scaled at catchment scale, these fluxes are probably relatively modest. Nevertheless, their quantification would better constrain nitrogen and carbon budgets in natural systems. [less ▲]

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See detailRecent advances for monitoring groundwater and pollutant fluxes using single-well applied tracer techniques
Jamin, Pierre ULiege; Orban, Philippe ULiege; Verreydt, Goedele et al

Conference (2018, September 10)

In many different hydrogeological investigations, quantifying groundwater fluxes is essential but often challenging due to the variability of hydraulic conditions in space and time. Traditional approaches ... [more ▼]

In many different hydrogeological investigations, quantifying groundwater fluxes is essential but often challenging due to the variability of hydraulic conditions in space and time. Traditional approaches used to estimate groundwater fluxes are based on hydraulic conductivity obtained from field pumping or slug tests that provide only order-of-magnitude estimates and hydraulic gradients that can also vary, especially in areas of active groundwater discharge or pumping. The Finite Volume Point Dilution Method (FVPDM) is a recently developed applied tracer technology able to measure accurately groundwater fluxes and to monitor continuously their changes with time. We report 10 years of application of the FVPDM in contrasted hydrogeological contexts, from porous alluvial to fractured-rock aquifers, including strong interactions with surface water and contrasting groundwater flow dynamics. The obtained results prove that the FVPDM is able to measure a wide range of groundwater fluxes from a few centimetres per day to hundreds of metres per day. These results also emphases the variability in groundwater fluxes, (1) with time in aquifers influenced by variable hydraulic conditions such as tidal effects and (2) in space where orders of magnitude difference in groundwater fluxes are observed between nearby monitoring wells at a given site. Preliminary results of continuing work have also shown the potential for the FVPDM approach to be coupled with contaminant specific sensors and with passive sampling technologies to quantify contaminant mass fluxes in the subsurface. Recent developments have also investigated the ability to assess groundwater flow directions at the well scale. [less ▲]

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See detailSimulation of groundwater and heat transfer for the geothermal use of flooded abandoned old-mines
Vopat, Olivier; Orban, Philippe ULiege; Brouyère, Serge ULiege et al

Conference (2018, September)

Groundwater in flooded abandoned mines could be used for geothermal purposes using heat-pumps and an open loop involving pumping and re-injection. Logically, warm water is usually expected to be pumped ... [more ▼]

Groundwater in flooded abandoned mines could be used for geothermal purposes using heat-pumps and an open loop involving pumping and re-injection. Logically, warm water is usually expected to be pumped (or injected) in the deep parts of the open network, and cold water is expected to be re-injected (or pumped) in the shallower parts. However, the feasibility and the durability of future ‘Ground Source Heat Pump system’ (GSHP) must be studied through a deep characterization of the subsoil but also using numerical models able to simulate groundwater flow and heat transfer in these complex geological environments. Depending on the type of abandoned mine, the true geometry of the interconnected network of open galleries and shafts can indeed be highly complex. A high-velocity water flow is expected in this type of network, while low-velocity groundwater flow occurs in less permeable fractured and porous rock massif. The SUFT3D code that allows combining in a single model, and in a fully interacting way, linear or distributed reservoirs to model groundwater flows in mine galleries and classical groundwater flow in the variably saturated equivalent porous surrounding media is developed to model heat transfer using the similarities existing between solute and heat transfer equations. The code is then used to test on a simplified case study based on the characteristics of the Werister coal mine (Belgium), the impact of the hydrogeological conditions and of technical choices on the feasibility and the durability of these geothermal systems. [less ▲]

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See detailNumerical study of the Martelange mine to be used as lower reservoir for constructing an Underground Pumped Storage Hydropower plant
Pujades, Estanis; Orban, Philippe ULiege; Archambeau, Pierre ULiege et al

in Advances in Geosciences (2018), 45

Underground Pumped Storage Hydropower (UPSH) using abandoned mines has been considered as a potential high capacity Energy Storage Systems. In UPSH plants, the excess of electricity is stored in the form ... [more ▼]

Underground Pumped Storage Hydropower (UPSH) using abandoned mines has been considered as a potential high capacity Energy Storage Systems. In UPSH plants, the excess of electricity is stored in the form of potential energy by pumping water from an underground reservoir (abandoned mine in this paper) to a surface reservoir, while electricity is produced (when the demand increases) discharging water from the surface into the underground reservoir. The main concerns may arise from the water exchanges occurring between the underground reservoir and the surrounding medium, which are relevant in terms of environmental impact and UPSH efficiency. Although the role of the water exchanges has been previously addressed, most studies are based on synthetic models. This work focuses on a real abandoned slate mine located in Martelange (Belgium). The effects of different rehabilitation works to prepare the mine as an underground reservoir are assessed in terms of groundwater exchanges and their associated consequences. [less ▲]

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See detailHydrochemical changes induced by underground pumped storage hydropower: influence of aquifer parameters in coal mine environments
Pujades, Estanis; Jurado, Anna; Orban, Philippe ULiege et al

in Advances in Geosciences (2018), 45

Underground pumped storage hydropower (UPSH) induces hydrochemical changes when water evolves to reach equilibrium with the atmosphere (in the surface reservoir) and with the surrounding medium (in the ... [more ▼]

Underground pumped storage hydropower (UPSH) induces hydrochemical changes when water evolves to reach equilibrium with the atmosphere (in the surface reservoir) and with the surrounding medium (in the underground reservoir). These hydrochemical changes may impact the environment and the efficiency, especially in coal mine environments were the presence of sulfide minerals is common. For this reason, it is needed to ascertain the variables that control the behavior of the system in order to establish criteria for the selection of abandoned mines to be used as underground reservoirs in future UPSH plants. Coupled hydro-chemical numerical models are used for investigating the influence of hydraulic parameters on the hydrochemical changes when pyrite is present in the surrounding medium. Results allow understanding how the hydraulic conductivity and the porosity affect the hydrochemical changes and their associated consequences in this kind of environments. [less ▲]

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