Soil aquifer treatment to remove priority organic pollutants in the Llobregat river area

The Llobregat River is the main source of water supply in this area. This river together with its aquifer has suffered from several damages which had contributed to endanger a suitable ecological and hydrological status; among them, pollution is a serious problem to deal with. In the last decades, the presence of organic pollutants in this river has been demonstrated [1,2]. Some of them are persistent to biological degradation and have shown to survive wastewater treatments almost unaltered and therefore they get surface waters where in some cases become recalcitrant pollutants. In order to mitigate the effect and presence of these compounds, Soil Aquifer Treatments (SAT) could be an approach since these treatments have demonstrated to be efficient to remove or decrease concentrations of such contaminants due to physico-chemical and biological processes occurring within the subsoil [3]. In the framework of the LIFE-ENSAT project, an organic substrate layer was installed in the basin of a recharge system located in the upper Llobregat delta aquifer. The aim was to enhance the degradation of contaminants through biochemical reactions on the reductive environment promoted in the unsaturated zone in order to improve the water quality of the system. In this work, the efficiency of this organic layer to remove organic pollutants included in European directives (2000/60/EC-2008/105/EC), such as triazines, pesticides or polyaromatic hydrocarbons (PAHs), has been evaluated. More than 80 compounds were analyzed; among them, 27 were priority pollutants while 6 were classified as preference substances (RD 60/2011).Peer ReviewedPostprint (published version

Reactive transport: a review of basic concepts with emphasis on biochemical processes

Reactive transport (RT) couples bio-geo-chemical reactions and transport. RT is important to understand numerous scientific questions and solve some engineering problems. RT is highly multidisciplinary, which hinders the development of a body of knowledge shared by RT modelers and developers. The goal of this paper is to review the basic conceptual issues shared by all RT problems, so as to facilitate advancement along the current frontier: biochemical reactions. To this end, we review the basic equations to indicate that chemical systems are controlled by the set of equilibrium reactions, which are easy to model, but whose rate is controlled by mixing. Since mixing is not properly represented by the standard advection-dispersion equation (ADE), we conclude that this equation is poor for RT. This leads us to review alternative transport formulations, and the methods to solve RT problems using both the ADE and alternative equations. Since equilibrium is easy, difficulties arise for kinetic reactions, which is especially true for biochemistry, where numerous challenges are open (how to represent microbial communities, impact of genomics, effect of biofilms on flow and transport, etc.). We conclude with the basic eleven conceptual issues that we consider fundamental for any conceptually sound RT effort.This work is part of grants MEDISTRAES III funded by MCIN/AEI/ PID2019-110212RB-C22 and MCIN/AEI/PID2019-110311RB-C21 and Water JPI project MARadentro (PCI2019-103603), and by the Catalan Water Agency through the project RESTORA (CA210/18/00040). IDAEA-CSIC is a Center of Excellence Severo Ochoa (Grant CEX2018-000794-S funded by MCIN/AEI/ 10.13039/501100011033).Peer ReviewedPostprint (published version

Tracer test modeling for characterizing heterogeneity and local-scale residence time distribution in an artificial recharge site

Artificial recharge of aquifers is a technique for improving water quality and increasing groundwater resources. Understanding the fate of a potential contaminant requires knowledge of the residence time distribution (RTD) of the recharged water in the aquifer beneath. A simple way to obtain the RTDs is to perform a tracer test. We performed a pulse injection tracer test in an artificial recharge system through an infiltration basin to obtain the breakthrough curves, which directly yield the RTDs. The RTDs turned out to be very broad and we used a numerical model to interpret them, to characterize heterogeneity, and to extend the model to other flow conditions. The model comprised nine layers at the site scaled to emulate the layering of aquifer deposits. Two types of hypotheses were considered: homogeneous (all flow and transport parameters identical for every layer) and heterogeneous (diverse parameters for each layer). The parameters were calibrated against the head and concentration data in both model types, which were validated quite satisfactorily against 1,1,2-Trichloroethane and electrical conductivity data collected over a long period of time with highly varying flow conditions. We found that the broad RTDs can be attributed to the complex flow structure generated under the basin due to three-dimensionality and time fluctuations (the homogeneous model produced broad RTDs) and the heterogeneity of the media (the heterogeneous model yielded much better fits). We conclude that heterogeneity must be acknowledged to properly assess mixing and broad RTDs, which are required to explain the water quality improvement of artificial recharge basins.Peer ReviewedPostprint (published version

Six artificial recharge pilot replicates to gain insight into water quality enhancement processes

The processes that control water quality improvement during artificial recharge (filtering, degradation, and adsorption) can be enhanced by adding a reactive barrier containing different types of sorption sites and promoting diverse redox states along the flow path, which increases the range of pollutants degraded. While this option looks attractive for renaturazing reclaimed water, three issues have to be analyzed prior to broad scale application: (1) a fair comparison between the system with and without reactive barrier; (2) the role of plants in prevention of clogging and addition of organic carbon; and (3) the removal of pathogens. Here, we describe a pilot installation built to address these issues within a waste water treatment plant that feeds on water reclaimed from the secondary outflow. The installation consists of six systems of recharge basin and aquifer with some variations in the design of the reactive barrier and the heterogeneity of the aquifer. We report preliminary results after one year of operation. We find that (1) the systems are efficient in obtaining a broad range of redox conditions (at least iron and manganese reducing), (2) contaminants of emerging concern are significantly removed (around 80% removal, but very sensitive to the compound), (3) pathogen indicators (E. coli and Enterococci) drop by some 3–5 log units, and (4) the recharge systems maintained infiltration capacity after one year of operation (only the system without plants and the one without reactive barrier displayed some clogging). Overall, the reactive barrier enhances somewhat the performance of the system, but the gain is not dramatic, which suggests that barrier composition needs to be improved.This study was supported by the Water Joint Programming Initiative (JPI)Water Challenges for a ChangingWorld 2014 through the project ACWAPUR (ACcelerated Water PURification during artificial recharge of aquifers: A tool to restore drinking water sources) and partially funded by the Spanish Ministry of Science, Innovation and Universities through PCIN-2015-245. We are very grateful to the staff of ‘Aguas de la Costa Brava' for their assistance, and to Ma Pau Serra-Roig and Ana Julia Acunha for their contribution to the chemical analysis and to Juli_a Garcia for his effort with the field site work.Peer ReviewedPostprint (published version

Reactive barriers for renaturalization of reclaimed water during soil aquifer treatment

Managed aquifer recharge (MAR) is known to increase available water quantity and to improve water quality. However, its implementation is hindered by the concern of polluting aquifers, which might lead to onerous treatment and regulatory requirements for the source water. These requirements might make MAR unsustainable both economically and energetically. To address these concerns, we tested reactive barriers laid at the bottom of infiltration basins to enhance water quality improvement during soil passage. The goal of the barriers was to (1) provide a range of sorption sites to favor the retention of chemical contaminants and pathogens; (2) favor the development of a sequence of redox states to promote the degradation of the most recalcitrant chemical contaminants; and (3) promote the growth of plants both to reduce clogging, and to supply organic carbon and sorption sites. We summarized our experience to show that the barriers did enhance the removal of organic pollutants of concern (e.g., pharmaceuticals and personal care products). However, the barriers did not increase the removal of pathogens beyond traditional MAR systems. We reviewed the literature to suggest improvements on the design of the system to improve pathogen attenuation and to address antibiotic resistance gene transfer.This research was funded by the Spanish Ministry of Science and Innovation CEX2018-000794-S), Water JPI (MARadentro-PCI2019-103603) and Catalan Water Agency (RESTORA-CA210/18/00040).Peer ReviewedPostprint (published version

Monitoring induced denitrification during managed aquifer recharge in an infiltration pond

Managed aquifer recharge (MAR) is a well-known technique for improving water quality and increasing groundwater resources. Denitrification (i.e. removal of nitrate) can be enhanced during MAR by coupling an artificial recharge pond with a permeable reactive layer (PRL). In this study, we examined the suitability of a multi-isotope approach for assessing the long-term effectiveness of enhancing denitrification in a PRL containing vegetal compost. Batch laboratory experiments confirmed that the PRL was still able to enhance denitrification two years after its installation in the infiltration pond. At the field scale, changes in redox indicators along a flow path and below the MAR-PRL system were monitored over 21¿months during recharge and non-recharge periods. Results showed that the PRL was still releasing non-purgeable dissolved organic carbon five years after its installation. Nitrate concentration coupled with isotopic data collected from the piezometer network at the MAR system indicated that denitrification was occurring in the saturated zone immediately beneath the infiltration pond, where recharged water and native groundwater mix. Furthermore, longer operational periods of the MAR-PRL system increased denitrification extent. Multi-isotope analyses are therefore proved to be useful tools in identifying and quantifying denitrification in MAR-PRL systems.Peer ReviewedPostprint (author's final draft

Magister : revista de formación del profesorado e investigación educativa

Resumen tomado de la publicaciónHablar de psicomotricidad es pensar en esa mutua relación existente entre actividad psíquica y función motriz. La función motriz no es nada sin el componente psíquico. Por la intervención del psiquismo, el movimiento se convierte en 'praxia'. El movimiento tiene una gran importancia en el desarrollo psíquico global del niño e incide en su personalidad, en su forma de comunicación y expresión, en la asimilación de nociones, en su escolaridad posterior, etc. Las corrientes pedagógicas actuales tienden a integrar plenamente el cuerpo en la acción educativa y a reconocer la influencia de la mediación corporal en el desarrollo neuropsicológico del niño. En ellas, se resalta la 'acción vivida o vivenciada', es decir, toda actividad corporal es creada, construida y vivida por el propio niño.AsturiasUniversidad de Oviedo. Escuela Universitaria de Magisterio; Calle Aniceto Sela, s. n.; 33005 Oviedo; +34985230970;ES

Soil aquifer treatment to remove priority organic pollutants in the Llobregat river area

The Llobregat River is the main source of water supply in this area. This river together with its aquifer has suffered from several damages which had contributed to endanger a suitable ecological and hydrological status; among them, pollution is a serious problem to deal with. In the last decades, the presence of organic pollutants in this river has been demonstrated [1,2]. Some of them are persistent to biological degradation and have shown to survive wastewater treatments almost unaltered and therefore they get surface waters where in some cases become recalcitrant pollutants. In order to mitigate the effect and presence of these compounds, Soil Aquifer Treatments (SAT) could be an approach since these treatments have demonstrated to be efficient to remove or decrease concentrations of such contaminants due to physico-chemical and biological processes occurring within the subsoil [3]. In the framework of the LIFE-ENSAT project, an organic substrate layer was installed in the basin of a recharge system located in the upper Llobregat delta aquifer. The aim was to enhance the degradation of contaminants through biochemical reactions on the reductive environment promoted in the unsaturated zone in order to improve the water quality of the system. In this work, the efficiency of this organic layer to remove organic pollutants included in European directives (2000/60/EC-2008/105/EC), such as triazines, pesticides or polyaromatic hydrocarbons (PAHs), has been evaluated. More than 80 compounds were analyzed; among them, 27 were priority pollutants while 6 were classified as preference substances (RD 60/2011).Peer Reviewe

Soil aquifer treatment to remove priority organic pollutants in the Llobregat river area

The Llobregat River is the main source of water supply in this area. This river together with its aquifer has suffered from several damages which had contributed to endanger a suitable ecological and hydrological status; among them, pollution is a serious problem to deal with. In the last decades, the presence of organic pollutants in this river has been demonstrated [1,2]. Some of them are persistent to biological degradation and have shown to survive wastewater treatments almost unaltered and therefore they get surface waters where in some cases become recalcitrant pollutants. In order to mitigate the effect and presence of these compounds, Soil Aquifer Treatments (SAT) could be an approach since these treatments have demonstrated to be efficient to remove or decrease concentrations of such contaminants due to physico-chemical and biological processes occurring within the subsoil [3]. In the framework of the LIFE-ENSAT project, an organic substrate layer was installed in the basin of a recharge system located in the upper Llobregat delta aquifer. The aim was to enhance the degradation of contaminants through biochemical reactions on the reductive environment promoted in the unsaturated zone in order to improve the water quality of the system. In this work, the efficiency of this organic layer to remove organic pollutants included in European directives (2000/60/EC-2008/105/EC), such as triazines, pesticides or polyaromatic hydrocarbons (PAHs), has been evaluated. More than 80 compounds were analyzed; among them, 27 were priority pollutants while 6 were classified as preference substances (RD 60/2011).Peer Reviewe