This study investigates the transport of pesticide thiophanate methyl (TM) as well as the co-transport of TM and titanium dioxide (TiO₂) nanoparticles in a water saturated column packed with quartz sand under various water conditions. Several ionic strengths (Is) (1, 10, 50 and 100 mM) and pH (3, 5, 7, 10) values were examined. The results from the transport experiments  were fitted and analyzed with the use of the ColloidFit software, while the results from cotransport experiments were fitted with a modified mathematical model of Katzourakis and Chrysikopoulos (2015). The results suggested that the lowest mass recovery rate was for the co-transport experiments with the addition of NaCl. It was shown that TM has a weak affinity for sand but a relatively strong affinity for TiO₂ at high Is and acidic pH. Furthermore, salinity was shown to have significant effects on TM removal.

How to cite: Chrysikopoulos, C. V., Stefanarou, A. S., Katzourakis, V. E., and Malandrakis, A. A.: Transport of thiophanate methyl in porous media in the presence of titanium dioxidenanoparticles, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2118, https://doi.org/10.5194/egusphere-egu23-2118, 2023.

How to cite: Yu, Y., Flury, M., Astner, A., Hayes, D., Zahid, T., and Chowdhury, I.: Aggregation Kinetics and Stability of Biodegradable Nanoplastics: Effects of Weathering and Proteins, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-142, https://doi.org/10.5194/egusphere-egu23-142, 2023.

Most studies focus on the detection of microplastic particles in different compartments of the environment. While impacts of microplastics on aquatic systems have already a wide acceptance in public, the research on microplastics in terrestrial systems is quite young. Our study aims to decipher the consequences of microplastics on the soil-water retention curve beyond the wilting point. Using a dew point WP4C hygrometer, we measured water retention curves of loess and sand samples with added microplastics, namely amorphous biopolymer, polystyrene in two sizes and three different types of UV-aged particles. All the different microplastics were added in concentrations of 0.1 wt.%, 0.5 wt.%, and 4.5 mg/kg. Reference samples without microplastics were prepared as well. For the analysis, we fitted the Webb model and calculated the water content at the wilting point and the slope of the soil-water retention curve. Our preliminary results did not show any significant differences between the different microplastics and their concentrations, however, the lowest slope and highest water content at pF 4.2 were observed in the samples without microplastics. Furthermore, the results indicated a greater variability with increasing size of microplastic particles.

How to cite: Laermanns, H., Rolf, M., Forche, S., Castrucci, E., Stelzer, A., and Bogner, C.: The influence of microplastics on the dry end of the soil-water retention curve, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10883, https://doi.org/10.5194/egusphere-egu23-10883, 2023.

Riverbank filtration (RBF) consists in forcing surface water to infiltrate and flow through an aquifer by means of a pumping well located near a surface water body. RBF aims to take advantage of the filtration capacity of aquifers to improve the water quality by removing a wide range of pollutants, including contaminants of emerging concern, by combining of physical, chemical and biological processes. However, the efficacy of RBF for eliminating substances that are considered persistent, mobile, and toxic (PMT), or very persistent and very mobile (vPvM), is expected to be low due to the high mobility of these substances. PMT and vPvM compounds, which are accumulated in the water cycle, are harmful to humans and the environment. For this reason, the processes affecting PMT and vPvM substances during RBF processes deserve to be deeply investigated.

This study aims at investigating the processes affecting PMT and vPvM substances in a site that behaves similarly to a RBF system. The study site is located in Sant Adriá del Besòs (Barcelona, Spain), where a constant pumping to drain an underground parking lot forces the water from the Besòs river to infiltrate and travel up to 230 m through the aquifer. Groundwater samples were collected from the river, and a set of piezometers aligned along the groundwater flow line between the Besòs river, and the underground parking lot allowed monitoring of the water at different stages after its infiltration. The samples were analysed by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) and PMT and vPvM were determined by a suspected screening approach.

This investigation provides new insights into the processes affecting PMT and vPvM substances and will have tremendous implications for determining groundwater quality in managed aquifer recharge contexts.

How to cite: Pujades, E., Sáez, C., Nikolenko, O., Scheiber, L., Bautista, A., Farré, M., and Jurado, A.: Processes affecting the behaviour of persistent, mobile, and toxic substances in a riverbank filtration system, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12881, https://doi.org/10.5194/egusphere-egu23-12881, 2023.

Water shortage is expected to exacerbate because of the increase pressure on water resources due to climate change and the growing population. It is deemed necessary to take advantage of all the available freshwater resources to cover the growing demand, especially in urban areas. However, urban aquifers are commonly contaminated by a wide range of organic contaminants of emerging concern (OCECs). OCECs, which comprise natural and synthetic compounds, are potentially hazardous to the environment and human health. Therefore, the processes controlling the behaviour of OCECs must be investigated to determine when and how the urban resources can be used safely and to design remediation strategies against them. The removal rate of OCECs depends on the temperature and redox conditions of groundwater that may be affected by anthropogenic activities like the exploitation of the geothermal potential of aquifers. The behaviour of some OCECs has been investigated in the context of managed aquifer recharge (MAR). However, the water range in MAR is lower than that expected around geothermal exploitations, and the behaviour of OCECs under similar conditions to that found around geothermal facilities should be evaluated. We have investigated the removal of 12 OCECs reported in the aquifers of Barcelona (Spain) by using batch experiments under different redox conditions and temperatures (25°C and 35°C). The results show that the removal rate of OCECs depends on the temperature, suggesting that the impact of geothermal exploitations must be considered when investigating the fate and evolution of OCECs in urban aquifers. Unexpectedly, it was observed that the removal rate could also decrease with the temperature, which may be related to the proliferation of different communities of bacteria depending on the temperature. Overall, this investigation supports the idea that it is possible to design geothermal facilities to promote the removal of OCECs.

How to cite: Jurado, A., Villa, M. A., Teixidó, M., Montemurro, N., Pérez, S., Foppen, J. W., and Pujades, E.: Organic contaminants of emerging concern (OCECs) in urban aquifers affected by geothermal exploitations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12959, https://doi.org/10.5194/egusphere-egu23-12959, 2023.

Phosphogypsum is a waste that results when fertilizer is obtained from phosphate through a wet chemical process. Phosphogypsum waste can entail negative consequences for the environment and human health since it is enriched in radionuclides from U-decay series and metal impurities. Phosphogypsum wastes are commonly accumulated in large stockpiles that are exposed to weathering processes. These stockpiles are located near the plants where phosphate is processed, which are usually located in coastal areas. This is the case of a phosphogypsum stack on the western side of the Tinto River estuary (Huelva, SW Spain), where the piles were directly settled on the marshland without using any isolation from 1968 to 2010. Here, in addition to the potential environmental impacts, the effect of the phosphogypsum wastes on human health are a source of concern since the piles are located near the city of Huelva (Spain). In this context, it is of paramount importance to assess the phosphogypsum leachate percolation into underlaid aquifer systems and the release of pollutants to the Tinto River.

This investigation aims at building a complex coupled hydro-chemical numerical model accounting with variable density to quantify how the pollutants are released to the environment. The first step has consisted in developing the flow numerical model that has been calibrated by fitting the piezometric head oscillations as a result of recharge processes and sea tide oscillations. The good fitting obtained during the calibration process (normalized RMS when comparing simulated and observed piezometric heads is less than the 10%) allows affirming that the estimated hydraulic parameters are accurate, and are consistent with the literature reviewed. Furthermore, the numerically calculated mass balance is consistent with the conceptually estimated one, the differences were as expected. Thus, the model allows simulating the flow processes and modelling predictive scenarios. The next steps will consist in implementing variable density and hydro-chemical, and possibly, hydromechanical processes.

This study, which uses numerical modelling, is intended to be useful for future work related to restoration measures and provides new insights into the water balance along with the complex processes occurring at the site.

How to cite: Coscia, F., Vázquez-Suñè, E., and Pujades, E.: Numerical modeling of flow in a phosphogypsum stack. Case of salt-marshes, Huelva, SW Spain., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3082, https://doi.org/10.5194/egusphere-egu23-3082, 2023.

Groundwater located in peri-urban areas may be impacted by many pollutants from different types of point or diffuse sources. About 40% of Brazil's waste is disposed of inappropriately in open dumps and constitutes a risk of contamination for aquifers. In the metropolitan region of the city of Salvador in northeastern Brazil, approximately 9,800 tons of solid waste are generated daily. This research aimed to delineate areas for the implementation of landfills and protection of peri-urban groundwater in Salvador and other catchments in northeastern Brazil. An integration of Boolean and fuzzy logic was performed using GIS, while the Analytic Hierarchy Process was used in a Multi Criteria Decision Analysis technique to generate the weights of the factors and criteria for the fuzzy model. From this methodology, two preliminary models were generated, one using the Boolean logic and the other the fuzzy logic. The first used restrictive criteria established by Brazilian legislation applied to fifteen factors/themes. In the second model, non-restrictive criteria were applied to eleven factors/themes based on technical knowledge and literature. The integration of the maps and the crossing of the models demonstrates that 6% of the studied areas are classified as highly adequate; 16% as adequate; 8% not suitable; and 70% are areas with total restrictions for locations of landfills and protection of aquifers.

How to cite: Leal, L., Purificação, C., Klammler, H., and Hatfield, K.: GIS‐based multi-criteria decision analysis for suitable locations of landfills and protection of peri-urban groundwater catchments: a case study in northeastern Brazil, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4754, https://doi.org/10.5194/egusphere-egu23-4754, 2023.

Emerging contaminants are becoming more prevalent in the environment. The consequences of emerging contaminants on the urban environment and living being's health are poorly understood by society. Pharmaceutical compound removal is not considered in designing a conventional sewage treatment facility. Instead, they were primarily concerned with organic and bacterial removal. Molecules containing xenobiotics whose physicochemical characteristics, such as small molecular size, water solubility, ionizability and volatility, make it challenging to identify, quantify, and degrade these complex chemicals. In the present study, we will take samples from Surface Water (SW) and Wastewater Treatment Plants (WTP) in the fast-growing Indian secondary cities (Bhopal, Bhuj and Kozhikode). We use analytical methods, including High-Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC) coupled with Mass Spectrometry (MS) to identify these compounds. The mentioned techniques have the potential to characterise complex environmental chemicals at low concentrations. In addition, Wetlands Construction can be an alternative and affordable technology for emerging compound treatment that performs satisfactorily for a variety of sewage types, including domestic sewage and wastewater. Our study identifies the contaminants present in the environment and the most popular analytical techniques for identifying and quantifying these compounds. We also present some potential solutions for the treatment of compounds by fusing several other technologies. This shows that in order to lessen or stop the deposition of these compounds into the environment, sewage treatment technologies need to be investigated and combined.

How to cite: Kumar, S., Tripathi, I. M., and Mohapatra, P. K.: Identifying wastewater pollutants from pharmaceutical residues and xenobiotic contaminants in Indian secondary cities, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-813, https://doi.org/10.5194/egusphere-egu23-813, 2023.

Urban shallow groundwater is highly impacted in terms of hydrogeology and water quality by anthropogenic activities and infrastructure, such as heating and cooling, surface sealing, leaking sewage pipes, and underground buildings. For a sustainable management of urban water resources, a better understanding of biogeochemical processes and its dynamics on a spatial and temporal scale in the urban subsurface is needed. So far, data sets including a critical minimum number of key parameters and an appropriate resolution in space and time have often been missing. Here, we introduce a multi-tracer approach applied to assess the shallow aquifers in Vienna. Water samples were collected twice, in autumn 2021 and spring 2022, respectively, from 150 groundwater wells in the city limits of Vienna. A comprehensive set of parameters (e.g. major ions, nutrients, heavy metals, water and nitrate stable isotopes) were analyzed to evaluate the spatial and seasonal variations in water origin and quality. Statistical analysis revealed that driving factors influencing groundwater quality include aquifer properties, interactions between groundwater-surface water, and redox conditions. A combined interpretation of conservative tracers indicated zones influenced by surface water - groundwater interactions that also influenced the water chemistry. Microbial anaerobic processes govern groundwater quality. In particular, contamination of nitrate from septic water and manure is locally reduced by denitrification, as proven by compound-specific isotope analysis, improving water quality. At the same time, other anaerobic processes, such as iron and manganese reduction, sulfate reduction, and methanogenesis deteriorate water quality. Finally, groundwater temperatures, up to 27°C, were observed close to urban underground infrastructure, hinting at subsurface buildings and surface sealing as stressors in shallow groundwater. In conclusion, our high resolution spatial sampling with the large set of parameters will not only allow a better understanding of groundwater quality dynamics, but also allows to evaluate effects to groundwater biodiversity and develop predictive mathematical models.

How to cite: Kaminsky, E., Englisch, C., Griebler, C., Steiner, C., Götzl, G., Knoeller, K., Sandén, H., Laaha, G., and Stumpp, C.: What are the driving factors affecting urban groundwater quality? A multi-tracer approach for the assessment of Vienna’s shallow aquifers, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5588, https://doi.org/10.5194/egusphere-egu23-5588, 2023.

Adequate management strategies are critically required to increase the resilience and long-term availability of groundwater resources in the light of progressive climate change and accelerating urbanization. Here, robustly parameterized numerical models, designed for simulating water flow as well as solute and heat transport processes in the hydrogeological subsurface, are powerful and widely established tools supporting decision making and planning.

Among other applications related to more general quantity- and quality-related questions, these numerical tools can be also used, e.g., for investigating the current thermal state of the subsurface and occurring changes due to artificial and natural influences. Models designed for this very specific task should include at least all major artificial objects (e.g., underground car parks, tunnels, buildings, sewer networks) which thermally contribute to the overall groundwater heat regime. For instance, the heat exchange between the subsurface and sewer systems may significantly contribute to the subsurface urban heat island effect and should, therefore, be implemented. However, fully three-dimensional implementations of sewer networks (typically with hundreds of kilometers of pipes) are mostly out of question when applying such numerical models, since it would be associated with large computational demands and increasing numerical instabilities.

To overcome this limitation, the focus of our ongoing research is to evaluate the suitability of an adaptive surrogate method to be coupled to existing numerical heat transport models. This method is based on linking expected thermal exchange rates between small subsurface objects (e.g., sewer pipes) and their surrounding area, which depend on site-specific parameters (e.g., surface-groundwater table distance, pipe dimensions, shapes and materials), with the spatial elements of an existing model mesh, e.g., as area-averaged heat sources or sinks. Numerical heat conduction simulations performed on pipe scale while employing seasonally changing ambient and sewer conditions point towards the importance of considering both stationary (such as materials) and transient input datasets (such as temperature fluctuations) in this linking process. The collection and pre-processing of both dataset types is performed in separate workflows employing standardized geographic information system (GIS) software. Based on these input datasets, heat flux calculations can be done either employing the numerical code itself (if the model code allows user-defined calculations) or, again, in a GIS-assisted step (in order to further reduce the computational demand during the runs of the numerical model).

The conceptual workflow, first results as well as expected advances and limitations of this surrogate approach will be critically discussed using the example of the well-documented heat transport case study of ‘Basel-City’. Among others, the aforementioned stationary and transient input datasets, and based on that, processed vertical heat fluxes will be presented for selected areas of the Swiss canton.

How to cite: Binder, M., Kossek, F., Engelmann, C., and Epting, J.: Surrogate-based implementation of sewer network structures into numerical heat transport models: First results of the Basel-City case study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11717, https://doi.org/10.5194/egusphere-egu23-11717, 2023.

With time, a lot of change in the nature of impurities, especially a surge in emerging contaminants in urban wastewater has been observed due to changing lifestyle, uncontrolled and mismanaged urban sprawl, increasing pollution and disease burden, and easy access to antibiotics. Conventional sewage treatment plants have thus faced challenges in treating emerging pollutants such as antibiotics, with variable success as reported in few studies.  Antibiotics are persistent in the environment and result into development of antimicrobial resistance. The concentration of antibiotics reportedly varies from µg/L to ng/L in raw/treated sewage which is generally dependent upon differences in environmental/social factors as well as treatment technology. The present study was conducted with the purpose of identifying the role of activated sludge process (ASP) in a standalone mode as well as in a hybrid mode duly integrated with upflow anaerobic sludge blanket reactor (UASB) in removal of antibiotics from the raw sewage. The antibiotics were analysed with a Liquid Chromatography Mass Spectrometer (LCMS), and the removal efficiencies were compared for both the treatment systems. The concentration of selected antibiotics in raw/treated sewage of the hybrid UASB-ASP varied in the range of 0.92-79025.9µg/L and 0.03-3439µg/L respectively. It was observed that the concentration of erythromycin was very less inspite of being used as a wide spectrum antibiotic against gram positive/gram-negative bacteria causing upper and lower respiratory diseases. An apparent reason could be that it is mainly metabolised by human liver and only 5% is excreted in active form. Also, low concentration of sulfamethoxazole and enrofloxacin were detected in the ranges 0.04-0.92µg/L and 0.03-0.94µg/L respectively in the raw/treated sewage. Notably, even these concentrations could also inhibit bacterial growth by altering microbial production of folic acid and induce antimicrobial resistance at sub lethal concentration. The removal efficiency for UASB-ASP for selected antibiotic was between 51.09% to 95.87% indicating an efficient reduction. Low concentration of sulfamethoxazole and enrofloxacin was observed within the range of 0.15 – 0.21 g/L and 0.007 – 0.01 µg/L in the raw/treated sewage of ASP. Negative removal (increased concentration in the treated sewage) was observed for erythromycin and ciprofloxacin, apparently because of resistance to degradation. The reduction of sulfamethoxazole, enrofloxacin, tetracycline was 27%, 52%, 65% where trimethoprim demonstrated maximum removal of 88% in ASP.  The hybrid UASB-ASP performed better than the standalone ASP with respect to reduction of all antibiotics, indicating that ASP can perform more efficiently when integrated with other technologies alongwith addition of a proper dosing of chlorination. Risk associated with the selected antibiotics from sewage treatment plant to the receiving environment (both water/soil) was quantified employing hazard quotient (HQ) using predicted no effect concentration (PNEC) values derived from literature. HQ for sulfamethoxazole was calculated to be above 1, and higher values were observed for trimethoprim (in the range of 589-628), and tetracycline (in the range of 405-722) indicating potential environmental concern for aquatic environment/soil, whichever may be of concern. No risk seemed to appear for indirect human exposure to enrofloxacin as indicated by the calculated values of HQ (0.004-0.02).

How to cite: Hazra, M., Joshi, H. J., and Vellanki, B. P.: Efficiency of activated sludge process for reduction of antibiotics from municipal wastewater , EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14782, https://doi.org/10.5194/egusphere-egu23-14782, 2023.

Nanoscience and nanotechnology have revolutionized many sectors of the industry with the development of novel materials and technologies. With the increasing use of nanomaterials in products and applications, the presence of nanoparticles in the environment, such as in soil, sediments, water, air, and biota, is inevitable. Understanding of the physical and chemical processes and environmental conditions that govern the fate and behavior of nanomaterials in the environment is essential to strengthen the environmental and human health security. This study discusses the role of physical and chemical processes and environmental conditions on the fate, transport, behavior, transformation, and toxicity of metal based nanoparticles and their environmental impacts, with a focus on terrestrial and aquatic systems, as well as plants and microorganisms. Research on the interactions of nanomaterials with the environment and biological systems will allow the development of models contributing to advancing knowledge on the behavior and fate of nanoparticles in the environment and assessing their potential risk in the environment.

How to cite: Darnault, C.: Nanomaterial Interactions with the Environment and Biological Systems: Implications for Soil, Water, Plants, and Microorganisms, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10830, https://doi.org/10.5194/egusphere-egu23-10830, 2023.

Escherichia coli, as an indicator of fecal contamination, can move from manure-amended soil to groundwater under rainfall or irrigation events. Predicting its vertical transport in the subsurface is essential for the development of engineering solutions to reduce the risk of microbiological contamination. In this study, we collected 302 datasets from 39 published papers addressing E. coli transport through saturated porous media and trained an automated machine learning model (H2O AutoML) to predict bacterial transport. Bacterial concentration, porous medium type, particle size, ionic strength, pore water velocity, and column length were used as input variables while the first-order attachment coefficient and spatial removal rate were set as target variables. The six input variables have low correlations with the target variables, namely, they cannot predict target variables independently. However, with the automated machine learning model, input variables can effectively predict the target variables. Among 20 candidate models, Gradient Boosting Machine showed the best performance. Among the six input variables, pore water velocity, ionic strength, particle size, and column length were more important than bacterial concentration and porous medium type. This method of using historical literature data to train automated machine learning models provides a new avenue for predicting the transport of other contaminants in the environment.

How to cite: Chen, F., Zhou, B., Yang, L., Chen, X., and Zhuang, J.: Predicting bacterial transport through saturated porous media using an automated machine learning model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16985, https://doi.org/10.5194/egusphere-egu23-16985, 2023.

With the increasing research on particles and biocolloids in terrestrial and aquatic systems, the transport and deposition of particles and biocolloids in porous media has become an important research topic. Based on the transport and deposition experiments of heavy metal pollutants and suspended-colloidal particles (SPs) in porous media, a nonlinear attachment-detachment model with adsorption hysteresis is proposed, which uses an adsorption function and scanning desorption isotherms to model the deposition effect of SPs. The reaction rate constant related to hysteretic characteristics essentially reflects the nonequilibrium hydrodynamic process during the transport of SPs. Static deposition tests and column experiments with pulse injection are used to calibrate the transport parameters. Column penetration experiments are performed under variable injection concentrations and seepage velocities. The results show that there is good agreement between simulated and experimental breakthrough curves (BTCs).

This model shows that increasing or decreasing the seepage velocity results in substantial changes in the penetration concentration of SPs, which is closely related to the adsorption hysteresis and the deposition dynamics of SPs. When the injection concentration is increased, the effluent concentration clearly increases, which reflects a nonlinear deposition process. In contrast, with a decrease in the injection concentration, the release effect of the already deposited SPs prolongs the penetration process, which is also related to the hysteresis. Previously proposed linear attachment-detachment models probably result in an overestimation of the adsorption capacity of porous media.

How to cite: Bai, B., Wu, H., and Bai, F.: A nonlinear attachment-detachment model with adsorption hysteresis for suspension-colloidal transport, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1194, https://doi.org/10.5194/egusphere-egu23-1194, 2023.