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The containment of contaminant plumes to protect groundwater from pollution is recognized as a frequent need in brownfield redevelopment. Plume containment can be physical, with slurry walls, jet grouting etc., or hydraulic, with wells capturing the subsurface flow that crosses the contaminated front (Pump & Treat), or a combination of both types. The choice of the most suitable technique is a difficult task, since various aspects must be taken into consideration. In this paper, we present a framework for evaluating barriers in terms of effectiveness and efficiency, along with a simplified approach for the evaluation of capital and operational costs. The contaminant mass discharge escaping from the containment system is a robust indicator of its effectiveness, and can be derived from modelling results. The abstracted water flowrate is a key indicator of the efficiency and sustainability of each option, especially in the long term. The methodology is tested in a simplified case study and in a real one, highlighting the relevance of modelling results in guiding the choice and design of contaminant source containment systems.
Alessandro Casasso; Agnese Salomone; Carlo Bianco; Giovanni Prassede; Rajandrea Sethi. A Quantitative Approach to Assessing the Technical and Economic Performance of Source Containment Options for Contaminated Aquifers. Sustainability 2021, 13, 5346 .
AMA StyleAlessandro Casasso, Agnese Salomone, Carlo Bianco, Giovanni Prassede, Rajandrea Sethi. A Quantitative Approach to Assessing the Technical and Economic Performance of Source Containment Options for Contaminated Aquifers. Sustainability. 2021; 13 (10):5346.
Chicago/Turabian StyleAlessandro Casasso; Agnese Salomone; Carlo Bianco; Giovanni Prassede; Rajandrea Sethi. 2021. "A Quantitative Approach to Assessing the Technical and Economic Performance of Source Containment Options for Contaminated Aquifers." Sustainability 13, no. 10: 5346.
Non-exhaust emissions (NEE) of particulate matter (PM) from brake, tyre, road pavement and railway wear, as well as resuspension of already deposited road dust, account for up to 90% by mass of total traffic-related PM emitted. This review aims at analysing the current knowledge on road traffic NEE regarding sources, particle generation processes, chemical and physical characterization, and mitigation strategies. The literature on this matter often presents highly variable and hardly comparable results due to the heterogeneity of NEE sources and the absence of standardized sampling and measurement protocols. As evidence, emission factors (EFs) were found to range from 1 mg km−1 veh−1 to 18.5 mg km−1 veh−1 for brake wear, and from 0.3 mg km−1 veh−1 to 7.4 mg km−1 veh−1 for tyre wear. Resuspended dust, which varies in even wider ranges (from 5.4 mg km−1 veh−1 to 330 mg km−1 veh−1 for cars), is considered the prevailing NEE source. The lack of standardized monitoring approaches resulted in the impossibility of setting international regulations to limit NEE. Therefore, up until now the abatement of NEE has only been achieved by mitigation and prevention strategies. However, the effectiveness of these measures still needs to be improved and further investigated. As an example, mitigation strategies, such as street washing or sweeping, proved effective in reducing PM levels, but only in the short term. The replacement of internal combustion engines vehicles with electric ones was instead proposed as a prevention strategy, but there are still concerns regarding the increase of NEE deriving from the extra weight of the batteries. The data reported in this review highlighted the need for future studies to broaden their research area, and to focus not only on the standardization of methods and the introduction of regulations, but also on improving already existing technologies and mitigating strategies.
Amelia Piscitello; Carlo Bianco; Alessandro Casasso; Rajandrea Sethi. Non-exhaust traffic emissions: Sources, characterization, and mitigation measures. Science of The Total Environment 2021, 766, 144440 .
AMA StyleAmelia Piscitello, Carlo Bianco, Alessandro Casasso, Rajandrea Sethi. Non-exhaust traffic emissions: Sources, characterization, and mitigation measures. Science of The Total Environment. 2021; 766 ():144440.
Chicago/Turabian StyleAmelia Piscitello; Carlo Bianco; Alessandro Casasso; Rajandrea Sethi. 2021. "Non-exhaust traffic emissions: Sources, characterization, and mitigation measures." Science of The Total Environment 766, no. : 144440.
Borehole heat exchangers (BHEs) generally employ water-antifreeze solutions to allow working fluid temperatures to fall below 0 °C. However, some local regulations have forbidden antifreeze additives (even non-toxic ones) to avoid groundwater pollution in case of pipe leakage. This paper presents a techno-economic and environmental analysis of four different fluids: propylene glycol at 25% and 33% weight concentrations, calcium chloride at 20% weight concentration (CaCl2 20%), and pure water. Thermal loads from 36 case studies in six different climate zones are used to perform BHE sizing and compare the abovementioned fluids from the economic, operational, and environmental points of view. The economic analysis and the carbon footprint assessment are performed on a life cycle of 25 years considering the installation (BHE drilling, fluid) and operation (heat pump and ground-side circulation pump energy demand, fluid replacement) of the simulated GSHPs. Results highlight that using pure water as a heat carrier fluid is convenient for cooling-dominated buildings but, for heating-dominated buildings, this choice leads to a noticeable increase of the BHE needed length which is not compensated by the lower operational costs. On the other hand, avoiding the use of antifreeze additives generally leads to a reduction of the lifetime carbon footprint, with a few exceptions in very cold climates. CaCl2 20% proves to be a good choice in most cases, both from the economic and the environmental points of view, as it allows a strong reduction of the installed BHE length in cold climates with a low additional cost and carbon footprint.
Nicola Bartolini; Alessandro Casasso; Carlo Bianco; Rajandrea Sethi. Environmental and Economic Impact of the Antifreeze Agents in Geothermal Heat Exchangers. Energies 2020, 13, 5653 .
AMA StyleNicola Bartolini, Alessandro Casasso, Carlo Bianco, Rajandrea Sethi. Environmental and Economic Impact of the Antifreeze Agents in Geothermal Heat Exchangers. Energies. 2020; 13 (21):5653.
Chicago/Turabian StyleNicola Bartolini; Alessandro Casasso; Carlo Bianco; Rajandrea Sethi. 2020. "Environmental and Economic Impact of the Antifreeze Agents in Geothermal Heat Exchangers." Energies 13, no. 21: 5653.
Humic acid-coated goethite nanoparticles (HA-GoeNPs) have been recently proposed as an effective reagent for the in situ nanoremediation of contaminated aquifers. However, the effective dosage of these particles has been studied only at laboratory scale to date. This study investigates the possibility of using HA-GoeNPs in remediation of real field sites by mimicking the injection and transport of HA-GoeNPs under realistic conditions. To this purpose, a three-dimensional (3D) transport experiment was conducted in a large-scale container representing a heterogeneous unconfined aquifer. Monitoring data, including particle size distribution, total iron (Fetot) content and turbidity measurements, revealed a good subsurface mobility of the HA-GoeNP suspension, especially within the higher permeability zones. A radius of influence of 2 m was achieved, proving that HA-GoeNPs delivery is feasible for aquifer restoration. A flow and transport model of the container was built using the numerical code Micro and Nanoparticle transport Model in 3D geometries (MNM3D) to predict the particle behavior during the experiment. The agreement between modeling and experimental results validated the capability of the model to reproduce the HA-GoeNP transport in a 3D heterogeneous aquifer. Such result confirms MNM3D as a valuable tool to support the design of field-scale applications of goethite-based nanoremediation.
Milica Velimirovic; Carlo Bianco; Natalia Ferrantello; Tiziana Tosco; Alessandro Casasso; Rajandrea Sethi; Doris Schmid; Stephan Wagner; Kumiko Miyajima; Norbert Klaas; Rainer U. Meckenstock; Frank Von Der Kammer; Thilo Hofmann. A Large-Scale 3D Study on Transport of Humic Acid-Coated Goethite Nanoparticles for Aquifer Remediation. Water 2020, 12, 1207 .
AMA StyleMilica Velimirovic, Carlo Bianco, Natalia Ferrantello, Tiziana Tosco, Alessandro Casasso, Rajandrea Sethi, Doris Schmid, Stephan Wagner, Kumiko Miyajima, Norbert Klaas, Rainer U. Meckenstock, Frank Von Der Kammer, Thilo Hofmann. A Large-Scale 3D Study on Transport of Humic Acid-Coated Goethite Nanoparticles for Aquifer Remediation. Water. 2020; 12 (4):1207.
Chicago/Turabian StyleMilica Velimirovic; Carlo Bianco; Natalia Ferrantello; Tiziana Tosco; Alessandro Casasso; Rajandrea Sethi; Doris Schmid; Stephan Wagner; Kumiko Miyajima; Norbert Klaas; Rainer U. Meckenstock; Frank Von Der Kammer; Thilo Hofmann. 2020. "A Large-Scale 3D Study on Transport of Humic Acid-Coated Goethite Nanoparticles for Aquifer Remediation." Water 12, no. 4: 1207.
Borehole heat exchangers (BHEs) commonly reach depths of several tens of meters and cross different aquifers. Concerns have been raised about the possibility of boreholes to act as preferential pathways for contaminant transport among aquifers (cross-contamination). This article employs numerical modelling of contaminant transport in the subsurface to address these concerns. A common hydrogeological setup is simulated, composed of three layers: A shallow contaminated and a deep uncontaminated aquifer separated by an aquitard, all crossed by a permeable borehole. The hydraulic conductivity of the borehole and, to a lesser extent, the vertical hydraulic gradient between the aquifers are the key factors of cross-contamination. Results of the numerical simulations highlight that, despite the severe conditions hypothesized in our modelling study, the cross-contamination due to the borehole is negligible when filled with a slightly permeable material such as a geothermal grout properly mixed and injected. A good agreement was found with analytical formulas used for estimating the flow rate leaking through the borehole and for studying the propagation of leaked contaminant into the deep aquifer.
Alessandro Casasso; Natalia Ferrantello; Simone Pescarmona; Carlo Bianco; Rajandrea Sethi. Can Borehole Heat Exchangers Trigger Cross-Contamination between Aquifers? Water 2020, 12, 1174 .
AMA StyleAlessandro Casasso, Natalia Ferrantello, Simone Pescarmona, Carlo Bianco, Rajandrea Sethi. Can Borehole Heat Exchangers Trigger Cross-Contamination between Aquifers? Water. 2020; 12 (4):1174.
Chicago/Turabian StyleAlessandro Casasso; Natalia Ferrantello; Simone Pescarmona; Carlo Bianco; Rajandrea Sethi. 2020. "Can Borehole Heat Exchangers Trigger Cross-Contamination between Aquifers?" Water 12, no. 4: 1174.
One of the main technical problems faced during field-scale injections of iron microparticles (mZVI) for groundwater nanoremediation is related to their poor colloidal stability and mobility in porous media. In this study, a shear-thinning gel, composed of a mixture of two environmentally friendly biopolymers, i.e., guar gum and xanthan gum, was employed to overcome these limitations. The slurry rheology and particle mobility were characterized by column transport tests. Then, a radial transport experiment was performed to mimic the particle delivery in more realistic conditions. The gel, even at a low polymeric content (1.75 g/L), proved effective in enhancing the mobility of high concentrated mZVI suspensions (20 g/L) in field-like conditions. The high radius of influence (73 cm) and homogeneous iron distribution were achieved by maintaining a low injection overpressure (
Federico Mondino; Amelia Piscitello; Carlo Bianco; Andrea Gallo; Alessandra De Folly D’Auris; Tiziana Tosco; Marco Tagliabue; Rajandrea Sethi. Injection of Zerovalent Iron Gels for Aquifer Nanoremediation: Lab Experiments and Modeling. Water 2020, 12, 826 .
AMA StyleFederico Mondino, Amelia Piscitello, Carlo Bianco, Andrea Gallo, Alessandra De Folly D’Auris, Tiziana Tosco, Marco Tagliabue, Rajandrea Sethi. Injection of Zerovalent Iron Gels for Aquifer Nanoremediation: Lab Experiments and Modeling. Water. 2020; 12 (3):826.
Chicago/Turabian StyleFederico Mondino; Amelia Piscitello; Carlo Bianco; Andrea Gallo; Alessandra De Folly D’Auris; Tiziana Tosco; Marco Tagliabue; Rajandrea Sethi. 2020. "Injection of Zerovalent Iron Gels for Aquifer Nanoremediation: Lab Experiments and Modeling." Water 12, no. 3: 826.
Pump and treat (P&T) systems are still widely employed for the hydraulic containment of contaminated groundwater despite the fact that their usage is decreasing due to their high operational costs. A way to partially mitigate such costs, both in monetary and environmental terms, is to perform heat exchange (directly or with a heat pump) on the groundwater extracted by these systems, thus providing low-carbon and low-cost heating and/or cooling to buildings or industrial processes. This opportunity should be carefully evaluated in view of preserving (or even improving) the removal efficiency of the remediation process. Therefore, the heat exchange should be placed upstream or downstream of all treatments, or in an intermediate position, depending on the effect of water temperature change on the removal efficiency of each treatment step. This article provides an overview of such effects and is meant to serve as a starting reference for a case-by-case evaluation. Finally, the potentiality of geothermal use of P&T systems is assessed in the Italian contaminated Sites of National Interest (SIN), i.e., the 41 priority contaminated sites in Italy. At least 29 of these sites use pumping wells as hydraulic barriers or P&T systems. The total discharge rate treated by these plants exceeds 7000 m3/h and can potentially provide about 33 MW of heating and/or cooling power.
Alessandro Casasso; Tiziana Tosco; Carlo Bianco; Arianna Bucci; Rajandrea Sethi. How Can We Make Pump and Treat Systems More Energetically Sustainable? Water 2019, 12, 67 .
AMA StyleAlessandro Casasso, Tiziana Tosco, Carlo Bianco, Arianna Bucci, Rajandrea Sethi. How Can We Make Pump and Treat Systems More Energetically Sustainable? Water. 2019; 12 (1):67.
Chicago/Turabian StyleAlessandro Casasso; Tiziana Tosco; Carlo Bianco; Arianna Bucci; Rajandrea Sethi. 2019. "How Can We Make Pump and Treat Systems More Energetically Sustainable?" Water 12, no. 1: 67.
Ground source heat pumps (GSHPs) gained increasing interest owing to benefits such as low heating and cooling costs, reduction of greenhouse gas emissions, and no pollutant emissions on site. However, GSHPs may have various possible interactions with underground and groundwater, which, despite the extremely rare occurrence of relevant damages, has raised concerns on their sustainability. Possible criticalities for their installation are (hydro)geological features (artesian aquifers, swelling or soluble layers, landslide-prone areas), human activities (mines, quarries, landfills, contaminated sites), and groundwater quality. Thermal alterations due to the operation of GSHPs may have an impact on groundwater chemistry and on the efficiency of neighboring installations. So far, scientific studies excluded appraisable geochemical alterations within typical ranges of GSHPs (±6 K on the initial groundwater temperature); such alterations, however, may occur for aquifer thermal energy storage over 40 °C. Thermal interferences among neighboring installations may be severe in urban areas with a high plant density, thus highlighting the need for their proper management. These issues are presented here and framed from a groundwater quality protection perspective, providing the basis for a discussion on critical aspects to be tackled in the planning, authorization, installation, and operation phase. GSHPs turn out to be safe and sustainable if care is taken in such phases, and the best available techniques are adopted.
Alessandro Casasso; Rajandrea Sethi. Groundwater-Related Issues of Ground Source Heat Pump (GSHP) Systems: Assessment, Good Practices and Proposals from the European Experience. Water 2019, 11, 1573 .
AMA StyleAlessandro Casasso, Rajandrea Sethi. Groundwater-Related Issues of Ground Source Heat Pump (GSHP) Systems: Assessment, Good Practices and Proposals from the European Experience. Water. 2019; 11 (8):1573.
Chicago/Turabian StyleAlessandro Casasso; Rajandrea Sethi. 2019. "Groundwater-Related Issues of Ground Source Heat Pump (GSHP) Systems: Assessment, Good Practices and Proposals from the European Experience." Water 11, no. 8: 1573.
Aquifer tests are the most appropriate method to determine the hydraulic behavior of an aquifer and the distribution of the hydrodynamic parameters that govern such behavior. This chapter illustrates the different type of aquifer tests (i.e., pumping, recovery and slug tests) and how to plan, execute and interpret them. Pumping tests consist in measuring the drawdown induced by the extraction of water from a well at a constant discharge rate in one or more observation points. They allow to first identify the hydraulic behavior of the aquifer, and thus to classify it as confined, leaky or unconfined, and then to determine, via a type curve matching method, the aquifer’s horizontal hydraulic conductivity, transmissivity and storativity. In the case of leaky aquifers, also the leakage factor can be calculated; and in the case of unconfined aquifers, the effective porosity and the vertical hydraulic conductivity can also be derived. Clearly, this interpretation relies on a number of ideal hypotheses being satisfied; this chapter also illustrates how to interpret pumping tests in the presence of factors that cause a deviation from the ideal behavior (e.g., finite, as opposed to infinitesimal, well radius and volume; partially penetrating well; presence of recharging or impermeable boundaries; inconsistent pumping rate; permeability damage close to the well). During recovery tests, residual drawdown measurements are carried out following the interruption of the pump at the end of a constant discharge pumping test. Theis’ recovery method, based on the superposition principle and normally used for the interpretation of the test, allows to determine the transmissivity of an aquifer. The last type of aquifer test, i.e., the slug test, consists in inducing an instantaneous variation of the static water level in a well or piezometer, and subsequently measuring the recovery over time of the undisturbed level in the same well. This method is used to determine the hydraulic conductivity of the aquifer in proximity of the well. In this chapter, the most common interpretation methods are presented, as well as the strategies to overcome limitations due to the existence of factors that cause a deviation from the ideal behavior. Finally, a suite of correlation-based, laboratory, and field methods available for the determination of an aquifer’s hydrodynamic parameters in alternative to aquifer tests are presented, and the applicability to different aquifer types and situations of each method, as well as their reliability is discussed.
Rajandrea Sethi; Antonio Di Molfetta. Aquifer Characterization. Environmental and Human Impact of Buildings 2019, 55 -112.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Aquifer Characterization. Environmental and Human Impact of Buildings. 2019; ():55-112.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Aquifer Characterization." Environmental and Human Impact of Buildings , no. : 55-112.
In this chapter, analytical solutions to the differential equation of mass transport for conservative solutes are illustrated. Their derivation relies on a number of simplifying hypotheses, including that: the medium is saturated, homogeneous and isotropic; water has constant density and viscosity, regardless of solute concentration; Darcy’s law is valid; flow directions and rates are uniform; transport parameters are constant within the domain; boundary conditions are constant in time. Solutions for one-, two- and three-dimensional geometries are presented, the former being mainly used for the interpretation of laboratory experiments, the latter two being more relevant for practical applications. Pulse and continuous solute release are considered. Notably, in a three-dimensional geometry a pulse input from a point source and a continuous input from a plane source are illustrated. A solution of the differential equation of mass transfer for the former contamination scenario was derived by Baetslé, while Domenico and Robbins proposed a model for the latter.
Rajandrea Sethi; Antonio Di Molfetta. Analytical Solutions to the Differential Equation of Mass Transport for Conservative Solutes. Environmental and Human Impact of Buildings 2019, 225 -237.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Analytical Solutions to the Differential Equation of Mass Transport for Conservative Solutes. Environmental and Human Impact of Buildings. 2019; ():225-237.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Analytical Solutions to the Differential Equation of Mass Transport for Conservative Solutes." Environmental and Human Impact of Buildings , no. : 225-237.
This chapter focuses on the mechanisms that govern the propagation of contaminants in aquifers. A qualitative and analytical description of the main hydrological, physico-chemical and biological process is provided. The hydrological mechanisms responsible for the transport and spreading of contaminants derive from the presence and movement of groundwater. The first of such processes is advection, according to which a compound is transported along the main direction of flow at seepage velocity. Molecular diffusion, instead, is responsible for the migration of the contaminant from high to low concentration areas, as a result of thermal agitation of water molecules. The last hydrological process is mechanical dispersion, which is a consequence of microscale heterogeneities present in the porous medium and results in a non-uniform velocity distribution relative to seepage velocity and the emergence of a transverse velocity component. During their migration within an aquifer, chemical compounds can also undergo chemical reactions that can lead to their transformation or degradation. The main reaction models and the most common types of reactions that are likely to occur in groundwater (i.e., acid-base reactions, complexation, hydrolysis, dissolution and precipitation, radioactive decay) are illustrated. Contaminant transformation and degradation can also be biologically mediated, primarily through microbial activity; such reactions are often described through first-order reaction kinetic models or Monod’s model. Finally, contaminant concentration in groundwater is also affected by sorption, a process by which compounds are removed from solution and transferred to the solid phase through a partitioning process typically characterized through isotherms. All these processes are described individually in this chapter, although in reality they occur simultaneously. The chapters that follow describe contaminant transport accounting for the concomitance of these processes.
Rajandrea Sethi; Antonio Di Molfetta. Mechanisms of Contaminant Transport in Aquifers. Environmental and Human Impact of Buildings 2019, 193 -217.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Mechanisms of Contaminant Transport in Aquifers. Environmental and Human Impact of Buildings. 2019; ():193-217.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Mechanisms of Contaminant Transport in Aquifers." Environmental and Human Impact of Buildings , no. : 193-217.
Aquifer contamination occurs following a release of chemical compounds in groundwater exploited for human consumption which poses a health risk to the consumers. There is a variety of anthropogenic causes of contamination, spanning from discharge of wastewater to the ground, to industrial or mining activities, from accidental spills to agricultural activities. The wide range of sources of contamination is reflected on the extremely broad and diverse set of contaminants, including biological, chemical and radioactive constituents. This chapter is dedicated to the chemical, physical and toxicological classification and characterization of chemical contaminants. Chemically, compounds can be broadly categorized as inorganic (e.g., metals, certain anions and cations, metalloids) or organic (i.e., containing at least one organic carbon). The main organic groups are described, including hydrocarbons, halogenated hydrocarbons, phenols, chlorobenzenes, nitroaromatic compounds, and a class of recently identified hazardous compounds, named emerging organic contaminants, is presented. A physical characterization of contaminants is essential for the prediction of their behavior once they are released to the ground and migrate either across the unsaturated zone towards the saturated medium, or directly in the aquifer. The most important physical characteristics affecting contaminant migration and illustrated in this chapter are physical state, miscibility with water, mass density, solubility in water and volatility. Finally, a toxicological classification of contaminants is provided, which categorizes them as threshold or non-threshold compounds, depending on whether their health effects are manifested only above a certain concentration or are independent of the exposure level (i.e., they induce genetic mutations which lead to cancer development). This classification lays the foundations for the definition of threshold concentration values in drinking water prescribed by national and international health agencies and regulatory authorities. A comparison of the guideline or regulatory values defined by the WHO, the US-EPA, the EU and the Italian law is provided.
Rajandrea Sethi; Antonio Di Molfetta. Groundwater Contaminants. Environmental and Human Impact of Buildings 2019, 169 -192.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Groundwater Contaminants. Environmental and Human Impact of Buildings. 2019; ():169-192.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Groundwater Contaminants." Environmental and Human Impact of Buildings , no. : 169-192.
Having provided a few analytical solutions for conservative solutes in the previous chapter, here the focus is on reactive solutes. The underlying hypotheses considered to be verified in order to obtain such solutions are the same as in the case of conservative solutes, with the additional requirement that: natural degradation can be described by first-order kinetics and the sorption isotherm is linear. Solutions for continuous and pulse releases are provided for one-, two-, and three-dimensional geometries, with line sources being considered in 2D geometries, and point and plain sources being hypothesized in 3D geometries.
Rajandrea Sethi; Antonio Di Molfetta. Analytical Solutions of the Differential Equation of Mass Transport for Reactive Solutes. Environmental and Human Impact of Buildings 2019, 239 -247.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Analytical Solutions of the Differential Equation of Mass Transport for Reactive Solutes. Environmental and Human Impact of Buildings. 2019; ():239-247.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Analytical Solutions of the Differential Equation of Mass Transport for Reactive Solutes." Environmental and Human Impact of Buildings , no. : 239-247.
In order to decrease the health risk deriving from a contamination event, a number of cleanup and corrective actions, collectively called remediation, can be implemented. Remediation can be applied directly at the site of contamination (in situ) or off site (ex situ), in which case the contaminated environmental component is physically extracted and treated in dedicated facilities at the surface. There are three main remedial approaches, generally categorized as: containment, which aims at preventing the migration of the contamination and hence the exposure of sensitive targets; active restoration, which entails removing or treating the contamination; and natural attenuation, which relies on naturally occurring biological, chemical and physical degradation or transformation processes that convert contaminants into harmless compounds. This Chapter reviews the main containment and remedial strategies available for the management of a groundwater contamination event, and provides valuable information to support the choice of the most suitable approach. The presented strategies include: free product recovery for light non-aqueous phase liquid removal; vacuum enhanced extraction; subsurface containment; pump and treat; air- and bio-sparging; permeable reactive barriers; in situ flushing; in situ oxidation; in situ bioremediation. Applicability, design options and operating conditions, as well as advantages and drawbacks of the presented methods are illustrated.
Rajandrea Sethi; Antonio Di Molfetta. Remediation of Contaminated Groundwater. Environmental and Human Impact of Buildings 2019, 331 -409.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Remediation of Contaminated Groundwater. Environmental and Human Impact of Buildings. 2019; ():331-409.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Remediation of Contaminated Groundwater." Environmental and Human Impact of Buildings , no. : 331-409.
This chapter provides a methodological approach for the characterization of a contamination event. This includes an examination of both the unsaturated (i.e., soil, soil gas and pore water) and the saturated media (i.e., soil and groundwater), and is structured around three main phases, i.e., collection and organization of existing data, development of a conceptual model, verification of the hypotheses made in the conceptual model through targeted investigations and sampling. After illustrating different strategies available for defining the sampling design, sampling techniques for the different phases of the unsaturated and saturated media are described. In the unsaturated medium, soil sampling can be carried out through rotary or direct push techniques; active and passive sampling methods are available for the collection of soil gas samples; lysimeters or filter-tip samplers can be used for sampling pore water. Sampling of the saturated medium should allow to obtain a three-dimensional reconstruction of the contaminated areas. Hence, recommendations on the spatial distribution of monitoring wells, on the available options for vertical sampling and on well-purging prior to sampling are provided. These aspects are fundamental for ensuring the collection of representative samples. Subsequently, the most important aspects that need to be kept into account when planning a sampling campaign are illustrated, in particular as regards sampling rate, sample collection method, sampling devices (e.g., bailers, pumps). On site measurement of water quality parameters is also considered, and the possibility of filtering samples during collection is discussed. Quality assurance and control protocols aimed at ensuring accuracy, precision and defensibility of acquired data are then illustrated. Finally, a brief overview of sample storage, blank collection and sampling materials is provided.
Rajandrea Sethi; Antonio Di Molfetta. Characterization of a Contamination Event. Environmental and Human Impact of Buildings 2019, 263 -299.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Characterization of a Contamination Event. Environmental and Human Impact of Buildings. 2019; ():263-299.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Characterization of a Contamination Event." Environmental and Human Impact of Buildings , no. : 263-299.
The focus of this chapter is human health risk assessment, which quantifies the human or environmental toxicological effects deriving from the release of a contaminant at a source and its migration towards exposed receptors. Essentially, this entails a quantitative description of the relations in the system “source—pathway—receptor”. The procedure of risk assessment consists in a sequence of steps, starting from site assessment investigations, through the definition of a conceptual model (i.e., identification of potential receptors and migration and exposure pathways, selection of constituents of concern), the determination of concentrations at the point of exposure, actual risk calculation, to a risk management decision making stage (i.e., uncertainty assessment, risk acceptability evaluation, determination of the maximum acceptable concentration levels at the source and the selection of appropriate interventions). The risk assessment itself can be carried out at an increasing degree of detail, through a tiered approach, illustrated in the chapter. A relevant focus of this chapter is the calculation of the concentration at the point of exposure via the determination of the natural attenuation factor. This factor is the cumulative result of the contaminant concentration attenuation in the course of its migration from the source to the point of exposure (e.g., partitioning between environmental components, attenuation in the unsaturated medium, dilution in the aquifer or in rivers, volatilization). Having determined the concentration at the point of exposure, the calculation of the rate of exposure is presented. With these two parameters it is then possible to calculate the risk deriving the exposure to carcinogenic or threshold compounds, following a contamination event. The carcinogenic risk is quantified by the incremental lifetime cancer risk, which is a function of the slope factor (defined in Chap. 9); the non-carcinogenic risk, instead, is quantified by the hazard quotient, which is a function of the reference dose (also defined in Chap. 9). Once the risk has been calculated, its acceptability can be evaluated according to the local legislation, and measures to manage it can be put into place.
Rajandrea Sethi; Antonio Di Molfetta. Human Health Risk Assessment. Environmental and Human Impact of Buildings 2019, 301 -329.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Human Health Risk Assessment. Environmental and Human Impact of Buildings. 2019; ():301-329.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Human Health Risk Assessment." Environmental and Human Impact of Buildings , no. : 301-329.
This chapter derives the differential equations of mass transport, distinguishing between conservative solutes (i.e., exclusively undergo hydrological processes) and reactive solutes (i.e., also undergo physico-chemical and/or biological processes). The differential equations are derived by imposing the mass balance of a generic solute in a representative elementary volume during a certain time interval.
Rajandrea Sethi; Antonio Di Molfetta. The Mass Transport Equations. Environmental and Human Impact of Buildings 2019, 219 -223.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. The Mass Transport Equations. Environmental and Human Impact of Buildings. 2019; ():219-223.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "The Mass Transport Equations." Environmental and Human Impact of Buildings , no. : 219-223.
In the previous chapter, the methods available for assessing the productivity and efficiency of a well were illustrated. However, a water supply system extends beyond the aquifer-well system, and is composed also of water transmission, treatment, storage and distribution elements. In this chapter, methods for the estimation of head losses occurring from the pumping well along the pipe network that transfers water to the treatment plant, before distribution to consumers, are illustrated. Along this network, there are distributed head losses, in straight pipes, and local head losses, in valves, bends and outlets into reservoirs. Commonly used empirical equations for the calculation of these losses and a method for identifying the optimal operating pumping rate are provided, based on a comparison between pump-related and system head losses. Furthermore, other aspects that need to be kept in mind in the design and long term maintenance of a highly efficient water supply system are highlighted.
Rajandrea Sethi; Antonio Di Molfetta. Optimization of a Water Supply System. Environmental and Human Impact of Buildings 2019, 127 -136.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Optimization of a Water Supply System. Environmental and Human Impact of Buildings. 2019; ():127-136.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Optimization of a Water Supply System." Environmental and Human Impact of Buildings , no. : 127-136.
Water supply systems must be designed in such a way to ensure groundwater extraction sustainability. In addition, the quality of pumped water must also be guaranteed, and this entails protecting the groundwater source from contamination. To do so, it is necessary to identify the physical and hydraulic characteristics of the soil, the unsaturated medium and the aquifer itself that influence the migration of contaminants spilled at the surface towards the aquifer, and hence potentially towards sensitive targets (i.e., drinking water pumping wells). The susceptibility of an aquifer to become polluted following a contaminant spill is called vulnerability, and its assessment is the focus of this chapter. Of the four categories of vulnerability assessment methods, i.e., overlay, index and statistical methods, and process-based simulation models, this chapter presents examples of the former two, which are of easier implementation and are widely used. Overlay methods define aquifer vulnerability on the basis of groundwater circulation and rely on the superposition of maps of the hydrogeologic, structural and morphologic setting. Index methods, instead, are based on the assignment of scores (sometimes weighed) to sets of parameters that are likely to affect the degree of vulnerability. Specific methods of these two categories described in detail in this chapter are the one developed by the Bureau de Recherches Géologiques et Minières in France, the Italian CNR-GNDCI and SINTACS methods, the US-EPA DRASTIC method and the British GOD method. The suitability of different methods is discussed, and how vulnerability assessment can be used to determine the risk of contamination is presented. On this basis, an example of contamination risk reduction strategies is illustrated.
Rajandrea Sethi; Antonio Di Molfetta. Aquifer Vulnerability and Contamination Risk. Environmental and Human Impact of Buildings 2019, 137 -159.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Aquifer Vulnerability and Contamination Risk. Environmental and Human Impact of Buildings. 2019; ():137-159.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Aquifer Vulnerability and Contamination Risk." Environmental and Human Impact of Buildings , no. : 137-159.
The largest source of human drinking water is stored and flows in the subsurface. Geological formations saturated in mobile groundwater that can be exploited for human use are called aquifers. This chapter introduces basic notions that set the ground for the understanding and description of subsurface water flow. First, the main properties of water are illustrated, with a particular focus on the forces it establishes with the solid matrix of a porous medium and on how these affect its mobility. Then, broad aquifer classifications are provided, based on their geographical location, their permeability characteristics as a function of the type of porosity (i.e., intergranular, fracture or karst), and their degree of confinement. The latter, which categorizes aquifers as unconfined, leaky or confined, has crucial implications on both their storage capacity and hydrodynamic behavior. The key parameters that characterize an aquifer’s storage capacity are porosity and storativity. While the former is indicative of the total amount of water that can be stored within a porous medium, the latter indicates the fraction that can be released. Both these notions apply to any aquifer type although the mechanism of water release is distinct in unconfined and confined aquifers: in the former, water is released under the effect of gravity alone, and storativity is called specific yield; in the latter, water is released as a result of water expansion that follows a pressure drop. Subsurface water transport, instead, is driven by the existence of a hydraulic gradient (i.e., a drop in hydraulic head, or piezometric level). Under specific hypotheses, groundwater flow can be described by Darcy’s law, which establishes a proportionality relationship between flow rate and hydraulic gradient, and can be used to map an aquifer’s flow field. The relation defined by Darcy’s law is measured by an aquifer-specific parameter called hydraulic conductivity. This parameter is crucial not only in the description of the transport capacity of a porous medium, but also in the calculation of its productivity, which is a function of the hydraulic conductivity and the thickness of an aquifer.
Rajandrea Sethi; Antonio Di Molfetta. Basic Concepts. Environmental and Human Impact of Buildings 2019, 1 -25.
AMA StyleRajandrea Sethi, Antonio Di Molfetta. Basic Concepts. Environmental and Human Impact of Buildings. 2019; ():1-25.
Chicago/Turabian StyleRajandrea Sethi; Antonio Di Molfetta. 2019. "Basic Concepts." Environmental and Human Impact of Buildings , no. : 1-25.