Trace metal behavior during in-situ iron removal tests in Leuven, Belgium

Vandenbohede, Alexander; Wallis, Ilka; Alleman, Tine

doi:10.1016/j.scitotenv.2018.08.126

Cited by 6 publications

(6 citation statements)

References 39 publications

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“…If recharge water introduces competitive ions, contaminant desorption and mobilization can occur from sorption sites associated with Fe (oxyhydr)oxides or other minerals. This was observed in Bolivar, Australia, during an ASR trial, where phosphate in the injectant limited the amount of As adsorption on Fe (oxyhydr)oxides during injection, while reductive dissolution of Fe (oxyhydr)oxides caused As mobilization during the storage and recovery phases. , At a subsurface iron removal site in Leuven, Belgium, where aerated groundwater was injected to decrease aqueous Fe(II) concentrations through precipitation and thus enhance the sorption capacity of the aquifer sediments, arsenic mobilization was attributed to competitive desorption from Fe (oxyhydr)oxides by native phosphate concentrations . Similarly, at a subsurface iron removal site in Schuwacht, The Netherlands, arsenic mobilization was attributed to both competitive desorption by phosphate and shifting redox conditions .…”

Section: Mechanisms Of Contaminant Mobilizationmentioning

confidence: 93%

“…41,145 At a subsurface iron removal site in Leuven, Belgium, where aerated groundwater was injected to decrease aqueous Fe(II) concentrations through precipitation and thus enhance the sorption capacity of the aquifer sediments, arsenic mobilization was attributed to competitive desorption from Fe (oxyhydr)oxides by native phosphate concentrations. 74 Similarly, at a subsurface iron removal site in Schuwacht, The Netherlands, arsenic mobilization was attributed to both competitive desorption by phosphate and shifting redox conditions. 73 Background phosphate concentrations have been shown to initially promote dissolution of arsenopyrite through monodentate mononuclear surface complexation in batch experiments simulating MAR.…”

Section: Mechanisms Of Contaminant Mobilizationmentioning

confidence: 99%

“…The pH increase could also enhance Mn(II) and Fe(II) sorption on Fe (oxyhydr)oxides 152 similar to methods of subsurface iron removal which target sorption of Fe(II) on Fe (oxyhydr)oxides. 73,74 However, promoting an increase in pH could be problematic for other geogenic contaminants if present (e.g., arsenate desorption from Fe (oxyhydr)oxides at pH > 8.5). 24 This highlights the need to holistically consider various contaminants and their corresponding geochemical cycles.…”

Section: Potential Mitigation Strategies Formentioning

confidence: 99%

“…We use a broad definition of MAR to describe any intentional injection or infiltration of water into an aquifer. This includes nontraditional artificial recharge sites, including subsurface iron removal sites , and experimental injection sites, ,, which have reported mobilization of geogenic contaminants, and findings are transferrable to traditional MAR sites. The majority of MAR case studies focus on injection sites which typically recharge oxic water into suboxic or anoxic aquifers with MAR-induced shifts in redox conditions being the primary driver of contaminant mobilization.…”

Section: Case Studiesmentioning

confidence: 99%

“…Pretreatment of recharge water has been proposed at sites in The Netherlands to address Mn(II) and Fe(II) issues in recovered water including adding pH-buffering amendments such as Na 2 CO 3 or NaOH to increase alkalinity and pH surrounding the ASR well and prevent dissolution of Mn/Fe carbonates. The pH increase could also enhance Mn(II) and Fe(II) sorption on Fe (oxyhydr)oxides similar to methods of subsurface iron removal which target sorption of Fe(II) on Fe (oxyhydr)oxides. , However, promoting an increase in pH could be problematic for other geogenic contaminants if present (e.g., arsenate desorption from Fe (oxyhydr)oxides at pH > 8.5) . This highlights the need to holistically consider various contaminants and their corresponding geochemical cycles.…”

Section: Potential Mitigation Strategies For Geogenic Contaminants Du...mentioning

confidence: 99%

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Mobilization of Arsenic and Other Naturally Occurring Contaminants during Managed Aquifer Recharge: A Critical Review

Fakhreddine

Prommer

Scanlon

et al. 2021

Environ. Sci. Technol.

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Population growth and climate variability highlight the need to enhance freshwater security and diversify water supplies. Subsurface storage of water in depleted aquifers is increasingly used globally to alleviate disparities in water supply and demand often caused by climate extremes including floods and droughts. Managed aquifer recharge (MAR) stores excess water supplies during wet periods via infiltration into shallow underlying aquifers or direct injection into deep aquifers for recovery during dry seasons. Additionally, MAR can be designed to improve recharge water quality, particularly in the case of soil aquifer treatment and riverbank filtration. While there are many potential benefits to MAR, introduction of recharge water can alter the native geochemical and hydrological conditions in the receiving aquifer, potentially mobilizing toxic, naturally occurring (geogenic) contaminants from sediments into groundwater where they pose a much larger threat to human and ecosystem health. On the basis of the present literature, arsenic poses the most widespread challenge at MAR sites due to its ubiquity in subsurface sediments and toxicity at trace concentrations. Other geogenic contaminants of concern include fluoride, molybdenum, manganese, and iron. Water quality degradation threatens the viability of some MAR projects with several sites abandoning operations due to arsenic or other contaminant mobilization. Here, we provide a critical review of studies that have uncovered the geochemical and hydrological mechanisms controlling mobilization of arsenic and other geogenic contaminants at MAR sites worldwide, including both infiltration and injection sites. These mechanisms were evaluated based on site-specific characteristics, including hydrological setting, native aquifer geochemistry, and operational site parameters (e.g., source of recharge water and recharge/recovery cycling). Observed mechanisms of geogenic contaminant mobilization during MAR via injection include shifting redox conditions and, to a lesser extent, pH-promoted desorption, mineral solubility, and competitive ligand exchange. The relative importance of these mechanisms depends on various site-specific, operational parameters, including pretreatment of injection water and duration of injection, storage, and recovery phases. This critical review synthesizes findings across case studies in various geochemical, hydrological, and operational settings to better understand controls on arsenic and other geogenic contaminant mobilization and inform the planning and design of future MAR projects to protect groundwater quality. This critical review concludes with an evaluation of proposed management strategies for geogenic contaminants and identification of knowledge gaps regarding fate and transport of geogenic contaminants during MAR.

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