HS8.2.8

In 2020, the European Union has established a recast of the 1998 EU Directive on the quality of water intended for human consumption, hereafter called Drinking Water Directive - DWD. One of the most significant evolutions in this recast is the introduction, through articles 7 of ‘a complete risk-based approach to water safety, covering the whole supply chain from the catchment area, abstraction, treatment, storage and distribution to the point of compliance’. In practice, a 3-level risk assessment and risk management is expected: (1) at the level of the catchment area (article 8), (2) at the level of the water supply systems (article 9) and (3) at the level of the domestic distribution system (article 10). In this context, the CASPER project, funded by SPGE in the Walloon Region of Belgium, aims at developing an integrated approach for the evaluation and management of pollution risks for peri-urban groundwater catchments. The approach, which fully complies with the requirements of the DWD recast, consists of several key components. First, point and diffuse pollution sources are identified in the groundwater catchment area based on a mapping of hazardous activities combined with a specific groundwater monitoring survey aiming at identifying specific tracers of such sources of pollution. In a second step, risks associated to each of the identified source of pollution is estimated based on the measurement of pollutant mass fluxes and mass discharges downgradient these sources. Finally, a groundwater flow and transport model is developed at the scale of the groundwater catchment area, with the aim of evaluating the cumulative effect of the multiple sources on groundwater quality deterioration in the catchment and at the abstraction points. The objective here is to describe the CASPER approach and to illustrate it using ongoing investigations in a peri-urban groundwater catchment exploiting groundwater from a chalk aquifer in Western Belgium.

How to cite: Brouyère, S., Balzani, L., and Orban, P.: The CASPER project: an integrated approach for pollution risk assessment in peri-urban groundwater catchment areas, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9958, https://doi.org/10.5194/egusphere-egu22-9958, 2022.

As in the rest of the world, the issues of global climate change impact and anthropogenic pressure on fresh drinking groundwater resources are very relevant in Georgia. This is especially important for Georgia, as this country is rich in fresh groundwater resources, but at the same time there are many challenges in terms of sustainable management of this resource.

Even before climate change trends became obvious, Georgia paid significant attention to groundwater research. Before early 1990’s, continuous hydrogeological monitoring had been carried out in order to protect groundwater resources. Detailed hydrogeological surveys have determined that Georgia’s natural fresh groundwater resources amount to 573 m³/sec and that water has the highest quality. Since then, for more than three decades, no centralized hydrogeological monitoring and groundwater cadaster have been carried out. Meanwhile, demand for fresh water has been steadily increasing, and uncontrolled drilling operations have and are being conducted for groundwater extraction. Failure to comply with environmental safety standards when selecting well construction and drilling works has a negative impact on both quantitative and qualitative characteristics of groundwater resources. Under conditions of improper operation, extraction of water from aquifers above the exploitation norm leads to their dry, impact on nearby water points (including springs), groundwater-related ecosystems, etc. Also, if one well crosses several aquifers, contamination of one of them (primarily a layer near the surface) causes the contaminants to migrate to other aquifers, which were normally considered to be naturally protected.

To assess the above pressures and to plan appropriate recommendations, the primary activity is monitoring studies. After many years, Georgia has been taking significant efforts since 2013 to restore the national network for fresh groundwater monitoring. LEPL National Environmental Agency (NEA), at the initiative of the Geology Department and with support from the Czech Development Agency (CzDA), has installed modern hydrogeological monitoring equipment on two wells in the Alazani artesian basin. The measure has been followed by gradual connection of water points to the monitoring network, and currently the monitoring covers 66 water points – 60 wells and 6 natural springs. Each well is equipped with a monitoring station, which uses sensors and dataloggers to perform continuous automatic monitoring of main quantitative and qualitative parameters of groundwater regimes (water discharge, level, pressure, temperature, pH, conductivity, TDS). Monitoring of springs is carried out by electronic sensors and data collector ,,Levelogger”. Twice a year, the NEA conducts chemical and bacteriological analysis of water samples from the monitoring water points.

Surveys conducted in 2013-2021 enabled the specialists of the Geology Department of the National Environment Agency to develop recommendations, which should be implemented in stages to assess the current state of groundwater resources and to use them racionally. In this regard, an informational hydrogeological report was published in 2021 - ,,Assessment of quantitative and qualitative characteristics of Fresh drinking groundwater resources of Georgia (analysis of the current situation, forecast and recommendations)”. The report was sent to all interested organizations - the scientific community and water management policy implementing agencies.

How to cite: Gaprindashvili, G., Kitiashvili, N., and Gaprindashvili, M.: Fresh groundwater resources of Georgia - Global climate change impact, anthropogenic pressure and activities for sustainable groundwater management, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-193, https://doi.org/10.5194/egusphere-egu22-193, 2022.

Increasing urbanization and climate-change-related measures have resulted in a growing demand for knowledge of the subsurface beneath cities and urban water management. Yet, knowledge of urban subsurfaces is not well documented and the urban anthropogenic geology's impact on groundwater is poorly understood. This study examines the impact of urban geology on the water balance and the dynamics of shallow groundwater at city-scale.  

An integrated surface-subsurface hydrological model was developed based on the MIKE SHE code for an urban domain in Odense, Denmark, covering an area of 10 km². In addition to basic hydrological processes, the model included urban processes in the form of overland drainage based on the degree of paved area, perimeter drains around major buildings, subsurface drainage, leakage from the sewer system, and groundwater abstraction. Three geological models were tested as input to the hydrological model. The hydrological models were run with two different horizontal resolutions, respectively a grid size of 10x10 and 50x50 m. The three geological models varied in complexity and representation of the near-surface urban geology: (1) V0, the base model, represented the layered regional geology beneath the urban area. (2) V1, a revised version of V0, included a representation of subsurface infrastructure; road and railroad base and embankment material, basements, and utility trenches. (3) V2, a revised version of V1, in addition included data from shallow geotechnical boreholes, yielding a representation of local areas with fill material. The urban near-surface geology in V1 and V2 were represented in a voxel model with sand/clay fraction classes. All versions of the hydrological model were calibrated based on the same setup, objective functions, and a calibration dataset consisting of 53 hydraulic head time-series and stream discharge observations within the model domain.

The results showed that the heterogeneity was smoothened when the hydrological model included a complex near-surface urban geology in a 50x50 m grid size and thus an effect of the urban geology was not reflected in the simulated head or the water balance. Meanwhile, the near-surface complexity in the V1 and V2 models led to a better model performance in terms of mean error and annual amplitude error, when the hydrological model had a 10x10 m grid size, which is closer to the scale of the heterogeneities.

The study illustrates that the manmade urban geology, in terms of subsurface obstacles and utility trenches, impacts shallow groundwater dynamics and flow paths. Moreover, it documents that it is possible to represent heterogeneous urban geology in a city-scale model, given the data is available. The results suggest that to simulate the effect of urban geology on shallow groundwater the computational grid needs to be of a size that can resolve the main subsurface infrastructures. In conclusion, a representation of the urban near-terrain geology improves the simulation of shallow groundwater and thus provides a better basis for urban planning, water management, and transport modeling.

How to cite: LaBianca, A., Kidmose, J., O. Sonnenborg, T., and Høgh Jensen, K.: Impact of urban geology on shallow groundwater, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7973, https://doi.org/10.5194/egusphere-egu22-7973, 2022.

The Katari Basin and Minor Lake of Titicaca (Bolivia) is one of the most populated and under pressure basins in the country where approximately 10% of the population lives at the national level (one million inhabitants). Urban development in the basin is rapid and is characterized by poor territorial planning and socio-productive patterns without appropriation in terms of caring for the urban, peri-urban, rural and aquatic environment, which has led, among others, to an accelerated and severe deterioration of water quality throughout the basin. It is for this reason that it is necessary to integrate the management of the productive aspects of the exploitation of its water resources with various environmental and socio-economic aspects of the area.

This study is within the framework of the "Lake Titicaca Sanitation Program" financed by the Inter-American Development Bank (IDB). The main objective of this program is to contribute to the decontamination of the Katari River basin and MinorTiticaca Lake and generate the necessary conditions to improve the quality of life of the population in this region, which is included in the different actions for the development and implementation of the Katari Basin Master Plan. The Katari Basin Management Unit (UGCK) will be the main beneficiary, which depends directly on the Ministry of Environment and Water (MMAyA) of Bolivia.

The implementation of a hydrological and hydrogeological model of the Basin would allow us to understand its operation; as well as quantify the general water balance of the Katari Basin and Minor Titicaca Lake. The specific objectives are: (i) Validate the conceptual hydrological model of the Katari basin and minor Titicaca lake; (ii) Update the existing spatial database for later use in the application of the hydrogeological conceptual model of the Katari basin and Minor Titicaca Lake; and (iii) Systematize the conceptual hydrogeological model of the Katari River basin for its integration with the validated surface hydrological model.

This study has allowed us to analyze the operation model of the Katari aquifers, where all hypotheses and data obtained are justified by consistent calculations. Although the hydrogeological model is considered correct, the information gaps found during the conceptualization process, as well as the results obtained through numerical modeling have shown that it is necessary to go deeper into certain aspects (sampling points inventory, improve hydrochemical monitoring, know the geology in depth in greater detail, among others).

This conceptual and numerical model, integrating the information available in a single platform, has made it possible to define the evaluation of risks or environmental impacts of the area and provide a frame of reference for other studies or more detailed models.

How to cite: Criollo, R., Scheiber, L., Poza, L., Valdivielso, S., Simunovic, P., and Vázquez-Suñé, E.: Validation, systematization and support for the implementation of a hydrological and hydrogeological model of the Katari basin and minor Titicaca lake, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7982, https://doi.org/10.5194/egusphere-egu22-7982, 2022.

Sustaining healthy living conditions in urban areas is a tremendous challenge in the European Union, and central to this mission is the supplying of freshwater resources. However, rapid urban growth and climate change will negatively impact water resources. Therefore, water shortage is encouraging research into potential alternative freshwater resources such as urban groundwater. Sometimes, urban groundwater is pumped to prevent damage to underground structures. This is the case of the underground parking lot of Sant Adrià del Besòs (Barcelona, NE Spain), where large amounts of urban groundwater are pumped to avoid seepage problems, which are directly poured to the sewage system.  This consideration ponders if this urban groundwater might be used as safe drinking-water because urban aquifers contain a vast array of pollutants such as pharmaceuticals.

This work investigated the occurrence and fate of more than 100 pharmaceuticals in the shallow aquifer of the Besòs Delta River, which main contamination source is a polluted river that receives discharges from wastewater treatment plants. To this end, river and groundwater samples were collected from February to May 2021 for the analysis of pharmaceuticals using a solid-phase extraction and high pressure liquid chromatography coupled to high resolution mass spectrometric methodology (HPLC-HRMS). Preliminary results showed that, in more than 70% of the samples, several pharmaceuticals such as anticonvulsants, antihypertensives, antibiotics, and antivirals were detected. More precisely, 38 substances were detected in all river samples and 15 were ubiquitous in groundwater samples.  The range of concentrations for all the compounds was between 2 ng/L and up to 880 ng/L. Moreover, the behavior of the compounds along the bank filtration until reach the pumping site, close to the parking lot, suggested that the natural attenuation of the pharmaceuticals likely to adsorption or oxidation-reduction processes occurred, as groundwater sampling points located close to the river presented the highest concentrations for the detected substances.  This observation allows inferring that the pumped urban groundwater could be used for different purposes including drinking water but further studies are required to quantify the coupled processes that control their fate in urban aquifers.

How to cite: Jurado, A., Labad, F., Scheiber, L., Criollo, R., Pérez, S., and Ginebreda, A.: Occurrence and fate of pharmaceuticals in urban groundwater, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7595, https://doi.org/10.5194/egusphere-egu22-7595, 2022.

The problem of nitrate contamination of groundwater is twofold. First, this pollutant degrades the quality of the water needed for human consumption and second, in excessive quantities, it disturbs the balance of ecosystems. While discrimination of the origin of this pollutant is a fundamental step in mitigation strategies, the multitude and mixing of nitrate sources generally makes this process difficult.

The Mesozoic chalk aquifer of the Mons basin (Belgium) covers an area of over 400 km². From a hydrogeological perspective, this aquifer is largely exploited for public water production (50 million m³/year) to answer the local demand but also with significant volume transfers to Brussels city and other regions. Nevertheless, year after year, an increase in nitrate concentration has been observed in several water catchments and is increasingly threatening the sustainability of some production sites. The land-uses in the area are various including fields, pastures, urban areas and industrial sites. Therefore, this diversity creates difficulties in identifying the origin of nitrate and mitigate the pollution. Finally, historical measurements of nitrate concentration in groundwater suggest the presence of denitrification processes along specific interfaces such as confined – unconfined limits.

The characterisation of the pollution and associated nitrate sources was carried out through multiple sampling campaigns covering the different land use zones and confined/unconfined areas. Classical hydrochemical analyses were performed to define the extent of the nitrate pollution, to locate potential denitrification zones and to highlight correlations with other major ions. In parallel, analyses of the stable isotopes of nitrate (δ¹⁵N and δ ¹⁸O) and boron (δ ¹¹B)were carried out. These isotopic ratios differ according to the chemical processes in which they were involved and allow to differentiate different sources of nitrate, including mineral or organic fertilisers, household waste degradation in landfills and possible leakage from sewer systems in urban areas.

The results of the sampling campaigns support some preliminary hypotheses while raising new questions. First, regarding the geographical distribution of nitrate, the agricultural areas in the south and west are the most affected. However, the highest local concentration peaks are generally found in urban areas, in urban zones of near former industrial sites. Furthermore, as expected, nitrate is generally absent from groundwater in confined areas of the aquifer. This observation is reinforced by higher iron concentrations and a lower redox potential in these zones. Regarding nitrate sources, isotope analyses reflect the influence of inorganic fertilisers in the most agricultural areas. At the same time, contamination due to sewage leakage seems to be significant in some specific large areas, also suggesting possible actions to mitigate the pollution.

How to cite: Christiaens, L., Goderniaux, P., Brouyère, S., and Orban, P.: Nitrate contamination in the chalk aquifer of the Mons Basin (Belgium), characterization by hydrochemical and isotopic analyses, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8553, https://doi.org/10.5194/egusphere-egu22-8553, 2022.

Groundwater catchment located in peri-urban areas may be impacted by many pollutants coming from different types of point or diffuse sources such as accidental spills, continuous hidden leaks in drainage networks, old landfills, treated/untreated wastewater and watercourses.

In the scope of the CASPER project, a new methodological approach has been developed based on field survey and interpretation of the collected data in order to distinguish between the different sources of contamination and mixtures of pollutants. First, the groundwater catchment area corresponding to the land surface perimeter in which abstracted groundwater is recharged is determined and characterised in hydrogeological terms. The possible sources of pollution are identified. In a second step, a groundwater and surface water monitoring survey is established, and water samples are collected focusing on a combination of physicochemical parameters and set of various hydrochemical indicators. In particular, different stable isotopes are considered. The NO₃- and B stable isotopes are used to distinguish between inputs linked to urban effluents, agricultural fertilisers and manure. Stable isotopes of SO₄^2- are used to distinguish between sulphide minerals oxidation, sulphur-carbon compounds mineralisation, lixiviation and human pollution. Moreover, the occurrence of specific molecules like pharmaceutical and lifestyle products (carbamazepine, caffeine, etc.) are used as effective tracers of anthropogenic contamination. Microbiological analyses are also undertaken to identify microbial populations associated with specific sources of pollution or specific biochemical reactions occurring in soil and groundwater. The resulting hydrochemical dataset is then processed using multivariate and clustering analyses.

In this context, the objective here is to describe the methodological approach developed for source identification and to illustrate this using a case study corresponding to a groundwater catchment is a chalk aquifer in Western Belgium.

How to cite: Balzani, L., Orban, P., and Brouyère, S.: Protection of peri-urban groundwater catchments: a multi-tracer approach for the identification of urban pollution sources, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11248, https://doi.org/10.5194/egusphere-egu22-11248, 2022.

Drinking water systems providing water to large cities are frequently located in alluvial or fluvio-glacial aquifers because their high permeability allows high extraction rates. Under normal conditions, these systems are recharged by river bank filtration and groundwater is collected at a sufficient distance to ensure that filtration through the aquifer provides water of good quality. However, during flood events, infiltration from the river bank may increase reducing the transit time, which may result in a higher risk of contamination. Identifying the water origin and its path from the river to the water work is key to establish operational strategies that minimize or prevent contamination during flood events. In this study, we investigate the potential of using anthropogenic gadolinium, which is increasingly used as a contrast agent in magnetic resonance imaging (MRI) and finally verted into rivers, as a conservative tracer to identify pathways of river bank filtration and then contribute to minimize the uncertainty of numerical models.

The test site is located in a rural sub-alpine basin. Several horizontal drains extract water from a fluvio-glacial aquifer by gravity. Under normal conditions, good quality water is collected; during flood events, due to the sudden increase in infiltration and decrease in transit times, water quality might deteriorate, as shown by the appearance of E. coli and coliforms. The concentration of anthropogenic gadolinium was measured in the river, in observation wells, and in the extracted drinking water over several years. The results demonstrated the great potential of gadolinium to identify and delineate the infiltration plumes produced by river bank filtration, which is contributing to reduce model uncertainty and evaluate the best pumping strategy for each of the drains in order to prevent water quality degradation.

How to cite: Marazuela, M. A., Brünjes, R., Tepe, N., Formentin, G., Erlmeier, K., and Hofmann, T.: Using anthropogenic gadolinium as a tracer to reduce the risk for contamination of river bank filtration systems, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4775, https://doi.org/10.5194/egusphere-egu22-4775, 2022.

Current demographics have projected that Lagos will become the world’s most populated megacity by the year 2100. This rapidly increasing human population has led to rapid depletion of groundwater resources of its highly productive coastal aquifers. The recharge processes and its drivers are yet to be quantified and understood. This challenge prompt the need to estimate the past and present recharge rate and understand the recharge processes in the megacity using WetSpass-M model. Input data such as land cover, DEM, slope, water depth, soil, temperature, precipitation, evapotranspiration, windspeed representing the past three decades (1990 to 2020) were inputted into the model. The findings established the two contrasting trends with recharge rates decreasing from 761mm/yr to 563mm/yr and runoff increasing from 292mm/yr to 400mm/yr. Similar spatial patterns of land use, simulated recharge and runoff were observed in the central area of Lagos. This supports the pressures from urbanization activities in the reduction of infiltrating water expected to recharge the aquifers and increasing runoff waters with potential of creating environmental hazards. The increasing runoff amount at the places near the water bodies serves as source water for Fiver Bank Filtration takeoff of Managed Aquifer Recharge (MAR) that can be captured, treated and stored in aquifers for later use. This when used will reduce the water availability crisis reported and projected in city of Lagos. 

How to cite: Olabode, O. and Comte, J.-C.: Conceptualization of recharge processes in the world most populous megacity in the past three decades using WetSpass-M Model: lessons and opportunities for Managed Aquifer Recharge (MAR), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12722, https://doi.org/10.5194/egusphere-egu22-12722, 2022.

Due to the current global change, there is a need looking for improved urban water management. Especially in urban areas, where most of the population is concentrated. These high dense areas require improvements on water quantity and quality, and Barcelona city is not an exception. Barcelona City Council has been studying different water alternatives to achieve the scarcity of the city since 1994. Following these new strategies, groundwater of the city is currently applied for different purposes in the city. Even more, aquifers are strategic water bodies that can be used during scarcity events for water supply ensuring an enough water quality.

In addition, Barcelona City Council installed different green infrastructures called Sustainable Urban Drainage Systems (SUDs). These installations reduce the extreme runoff events by promoting and facilitating the recharge of the aquifers. The installation of these systems are increasing, but there is a lack of the knowledge and understanding of the quality of the water infiltrated in the aquifer and their effects on the state of the groundwater bodies of the city, which can reduce the current quality of groundwater.

ASSET is a project funded and awarded by the Barcelona council under the call “Scientific research awards Urban in the Barcelona city”. The goal of this project is to evaluate the SUDs implemented in the city of Barcelona and provide improvements so that these systems are more efficient and fulfil the purpose of said facilities and advance toward an efficient and sustainable use of water, improving the adaptation capacity of the city to the current Climate Change and promoting the use of green infrastructures in their urban plans.

ASSET project aims to define an approach and set of tools for an integrated urban water management that it will help in the new plans of uses and it will ensure the good state of these resources. ASSET key drivers are: (1) Improve our knowledge on the underlying mechanisms involved and controls on contaminants-water-air interactions in an urban setting, which is crucial to reduce the exposure of environmental receptors; (2) To reduce the impact of the floods due to torrential rains increasing the permeable surfaces in the cities and peak flows that eventually arrives at the network of collectors and consequently to the treatment plant or the receiver; (3) Optimize groundwater quality control by setting out a list of performance indicators; (4)        Promote the reuse of water stored during the rainy season for its use in periods of drought; (5) Provide improved quantitative, mechanistically robust modelling tools to (i)      optimize urban water management in the context of the wider environment in the short term; and (ii) enhance our ability to develop effective strategies to mitigate the potential effects that future climate change may have on urban resources; (6)          Develop a reactive transport model to model the effectiveness of the proposed materials for the retention of contaminants.

How to cite: Scheiber, L., Teixidó, M., Criollo, R., Labad, F., Vázquez-Suñé, E., and Izquierdo, M.: ASSET project. Assessing SUDs Efficiency to Reduce Urban Runoff Water Contamination., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5474, https://doi.org/10.5194/egusphere-egu22-5474, 2022.

Rising populations, exacerbated urbanization, and climate change pose uncertainties on our traditional urban drinking water supplies. Stormwater harvesting schemes could replenish over-drafted groundwater resources, augmenting urban water supplies. However, urban stormwater runoff carries a myriad of dissolved contaminants (e.g., organics, metals, nutrients), which impair receiving water bodies. Moreover, some organic contaminants of urban origin —particularly persistent contaminants of emerging concern (known as CECs), like pesticides, plasticizers, flame retardants, etc.— may not be adequately removed by conventional infiltration treatments.Thus, it is important to fully understand their fate, transport, and effect in the built environment, while designing novel ‒or upgrading conventional‒ treatment systems. First, we have conducted field sampling campaigns to investigate contaminant presence, transport, and source apportionment, during storm events. Preliminary results have confirmed presence of pharmaceuticals (and their corresponding metabolites), pesticides and flame retardants in urban rainwater. Regarding potential treatments prior discharge to both surface and groundwater bodies, we have investigated several passive treatments. To enhance the treatment performance of conventional media, herein we propose sustainable, low-cost and low-energy reactive geomedia. For instance, pyrogenic carbonaceous materials (e.g., biochar) can adsorb trace organic and metal contaminants. We have conducted preliminary laboratory-scale batch experiments to investigate their removal capacities. Our results showed that biochar displayed faster sorption kinetics (<24h) and capacity compared to the other studied materials. Sand, commonly used in infiltration schemes, showed almost no reactivity, highlighting the need to study alternative materials to retain organic and inorganic contaminants from stormwater runoff. 

How to cite: Teixidó, M., Scheiber, L., Cruz-Castillo, E., Criollo, R., Montemurro, N., Labad, F., Pérez, S., and Vázquez-Suñé, E.: Occurrence and Removal of Emerging Contaminants in Urban Stormwater Runoff, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12636, https://doi.org/10.5194/egusphere-egu22-12636, 2022.

Pressure over water resources is increasing rapidly as a result of climate change and growing population. In this context, urban aquifers emerge as a valuable resource of fresh-water for cities. However, the quality of urban groundwater is degraded due to the presence of contaminants of emerging concern (CECs) that reach continuously urban aquifers from different recharge sources. The effects of CECs are largely unknown, but it is expected that they pose a risk for human health, soil, plants and animals. CECs are naturally degraded in aquifers and their degradation rates depend on the physico-chemical conditions (i.e., redox conditions and water temperature) of the groundwater, which may vary as a result of anthropogenic activities. Therefore, it is needed to establish the impact of anthropogenic activities on CECs to determine their behaviour under modified and variable physico-chemical conditions and allow the safely use of urban groundwater. One of these anthropogenic activities that potentially modify the physico-chemical conditions is the use of the subsurface to obtain cooling and heating energy through low-enthalpy geothermal energy (LEGE) systems. LEGE is a renewable and carbon-free energy whose utilization is currently growing. Thus, it is expected that in a near future the density of LEGE systems will increase over most cities. Then, our objective is to determine the impact of LEGE systems on the behaviour of CECs.

We have investigated the behaviour of CECs under the influence of LEGE by means of numerical models and considering different representative scenarios. The results show that the physico-chemical variations induced by LEGE systems modify notably the degradation rates of CECs, and thus, their concentrations on the downgradient side. Our results have significant implications for predicting the behaviour of CECs in urban aquifers and suggest the possibility of specifically design LEGE systems to improve in a passive way the quality of urban groundwater by eliminating CECs.

How to cite: Pujades Garnes, E., Jurado, A., Scheiber, L., Teixidó, M., Criollo, R., Vilarrasa, V., and Vázquez-Suñé, E.: On the influence of shallow geothermal energy on the behaviour of contaminants of emerging concern, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9140, https://doi.org/10.5194/egusphere-egu22-9140, 2022.