Evaluation of the stability of arsenic immobilized by microbial sulfate reduction using TCLP extractions and long-term leaching techniques

T Jong, David Parry

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    An investigation was conducted to evaluate the stability or leachability of arsenic immobilized by microbial sulfate reduction. Anoxic solid-phase samples taken from a bioreactor previously used to treat metal and As contaminated water using sulfate reducing bacteria (SRB) were subjected to the toxicity characteristic leaching procedure (TCLP) and long-term column leaching tests. The results from TCLP experiments showed that the concentration of As leached from solid-phase sulfide material (SSM) samples after an 18 h extraction time was <300 ?g l-1, which is below the current maximum Australian TCLP leachate value for As, and thus would not be characterized as a hazardous waste. In terms of percent total As leached, this was equivalent to <8.5% for SSM samples initially containing 61.3 mg kg-1 As. The levels of As extracted by the TCLP was found to be significantly lowered or underestimated in the presence of dissolved oxygen, with As concentrations increasing with decreasing headspace-to-leachant volume ratios. The concentration of As was also consistently higher in nitrogen purged extractions compared to those performed in air. This was attributed to the dissolution of Fe-sulfide precipitates and subsequent oxidation of Fe(II) ions and precipitation of ferric(hydr)oxides, resulting in the adsorption of soluble As and corresponding decrease in As concentrations. According to the experimental data, it is recommended that TCLP tests for As leachability should be performed at least in zero-headspace vessels or preferably under nitrogen to minimize the oxidation of Fe(II) to ferric(hydr)oxides. In long-term leaching studies (?68 days), it was found that the low solubility of the SSM ensured that rate of release of As was relatively slow, and the resulting leachate concentrations of As were below the current Australian guideline concentration for arsenic in drinking water. � 2005 Elsevier Ltd. All rights reserved.
    Original languageEnglish
    Pages (from-to)254-265
    Number of pages12
    JournalChemosphere
    Volume60
    Issue number2
    Publication statusPublished - 2005

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    arsenic
    leaching
    sulfate
    toxicity
    sulfide
    leachate
    oxide
    oxidation
    nitrogen
    sulfate-reducing bacterium
    evaluation
    hazardous waste
    bioreactor
    dissolved oxygen
    solubility
    vessel
    drinking water
    dissolution
    adsorption
    ion

    Cite this

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    title = "Evaluation of the stability of arsenic immobilized by microbial sulfate reduction using TCLP extractions and long-term leaching techniques",
    abstract = "An investigation was conducted to evaluate the stability or leachability of arsenic immobilized by microbial sulfate reduction. Anoxic solid-phase samples taken from a bioreactor previously used to treat metal and As contaminated water using sulfate reducing bacteria (SRB) were subjected to the toxicity characteristic leaching procedure (TCLP) and long-term column leaching tests. The results from TCLP experiments showed that the concentration of As leached from solid-phase sulfide material (SSM) samples after an 18 h extraction time was <300 ?g l-1, which is below the current maximum Australian TCLP leachate value for As, and thus would not be characterized as a hazardous waste. In terms of percent total As leached, this was equivalent to <8.5{\%} for SSM samples initially containing 61.3 mg kg-1 As. The levels of As extracted by the TCLP was found to be significantly lowered or underestimated in the presence of dissolved oxygen, with As concentrations increasing with decreasing headspace-to-leachant volume ratios. The concentration of As was also consistently higher in nitrogen purged extractions compared to those performed in air. This was attributed to the dissolution of Fe-sulfide precipitates and subsequent oxidation of Fe(II) ions and precipitation of ferric(hydr)oxides, resulting in the adsorption of soluble As and corresponding decrease in As concentrations. According to the experimental data, it is recommended that TCLP tests for As leachability should be performed at least in zero-headspace vessels or preferably under nitrogen to minimize the oxidation of Fe(II) to ferric(hydr)oxides. In long-term leaching studies (?68 days), it was found that the low solubility of the SSM ensured that rate of release of As was relatively slow, and the resulting leachate concentrations of As were below the current Australian guideline concentration for arsenic in drinking water. � 2005 Elsevier Ltd. All rights reserved.",
    keywords = "Adsorption, Bacteria, Contamination, Dissolution, Extraction, Leaching, Microbiology, Nitrogen, Oxidation, Sulfur compounds, Water, Leachability, Solid-phase sulfide material (SSM), Sulfate reducing bacteria (SRB), Toxicity characteristic leaching procedure (TCLP), Arsenic, arsenic, dissolved oxygen, ferric hydroxide, iron, nitrogen, sulfate, sulfide, water quality, water treatment, adsorption, analytic method, article, concentration response, dissolution, evaluation, extraction, leaching, oxidation, reduction, solid, solubility, sulfate reducing bacterium, Air, Bioreactors, Drug Toxicity, Ferric Compounds, Hazardous Waste, Oxidation-Reduction, Porosity, Sulfur-Reducing Bacteria, Time Factors, Water Pollutants, Chemical, Water Purification, Water Supply",
    author = "T Jong and David Parry",
    year = "2005",
    language = "English",
    volume = "60",
    pages = "254--265",
    journal = "Chemosphere",
    issn = "0045-6535",
    publisher = "Global Science Books",
    number = "2",

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    Evaluation of the stability of arsenic immobilized by microbial sulfate reduction using TCLP extractions and long-term leaching techniques. / Jong, T; Parry, David.

    In: Chemosphere, Vol. 60, No. 2, 2005, p. 254-265.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Evaluation of the stability of arsenic immobilized by microbial sulfate reduction using TCLP extractions and long-term leaching techniques

    AU - Jong, T

    AU - Parry, David

    PY - 2005

    Y1 - 2005

    N2 - An investigation was conducted to evaluate the stability or leachability of arsenic immobilized by microbial sulfate reduction. Anoxic solid-phase samples taken from a bioreactor previously used to treat metal and As contaminated water using sulfate reducing bacteria (SRB) were subjected to the toxicity characteristic leaching procedure (TCLP) and long-term column leaching tests. The results from TCLP experiments showed that the concentration of As leached from solid-phase sulfide material (SSM) samples after an 18 h extraction time was <300 ?g l-1, which is below the current maximum Australian TCLP leachate value for As, and thus would not be characterized as a hazardous waste. In terms of percent total As leached, this was equivalent to <8.5% for SSM samples initially containing 61.3 mg kg-1 As. The levels of As extracted by the TCLP was found to be significantly lowered or underestimated in the presence of dissolved oxygen, with As concentrations increasing with decreasing headspace-to-leachant volume ratios. The concentration of As was also consistently higher in nitrogen purged extractions compared to those performed in air. This was attributed to the dissolution of Fe-sulfide precipitates and subsequent oxidation of Fe(II) ions and precipitation of ferric(hydr)oxides, resulting in the adsorption of soluble As and corresponding decrease in As concentrations. According to the experimental data, it is recommended that TCLP tests for As leachability should be performed at least in zero-headspace vessels or preferably under nitrogen to minimize the oxidation of Fe(II) to ferric(hydr)oxides. In long-term leaching studies (?68 days), it was found that the low solubility of the SSM ensured that rate of release of As was relatively slow, and the resulting leachate concentrations of As were below the current Australian guideline concentration for arsenic in drinking water. � 2005 Elsevier Ltd. All rights reserved.

    AB - An investigation was conducted to evaluate the stability or leachability of arsenic immobilized by microbial sulfate reduction. Anoxic solid-phase samples taken from a bioreactor previously used to treat metal and As contaminated water using sulfate reducing bacteria (SRB) were subjected to the toxicity characteristic leaching procedure (TCLP) and long-term column leaching tests. The results from TCLP experiments showed that the concentration of As leached from solid-phase sulfide material (SSM) samples after an 18 h extraction time was <300 ?g l-1, which is below the current maximum Australian TCLP leachate value for As, and thus would not be characterized as a hazardous waste. In terms of percent total As leached, this was equivalent to <8.5% for SSM samples initially containing 61.3 mg kg-1 As. The levels of As extracted by the TCLP was found to be significantly lowered or underestimated in the presence of dissolved oxygen, with As concentrations increasing with decreasing headspace-to-leachant volume ratios. The concentration of As was also consistently higher in nitrogen purged extractions compared to those performed in air. This was attributed to the dissolution of Fe-sulfide precipitates and subsequent oxidation of Fe(II) ions and precipitation of ferric(hydr)oxides, resulting in the adsorption of soluble As and corresponding decrease in As concentrations. According to the experimental data, it is recommended that TCLP tests for As leachability should be performed at least in zero-headspace vessels or preferably under nitrogen to minimize the oxidation of Fe(II) to ferric(hydr)oxides. In long-term leaching studies (?68 days), it was found that the low solubility of the SSM ensured that rate of release of As was relatively slow, and the resulting leachate concentrations of As were below the current Australian guideline concentration for arsenic in drinking water. � 2005 Elsevier Ltd. All rights reserved.

    KW - Adsorption

    KW - Bacteria

    KW - Contamination

    KW - Dissolution

    KW - Extraction

    KW - Leaching

    KW - Microbiology

    KW - Nitrogen

    KW - Oxidation

    KW - Sulfur compounds

    KW - Water

    KW - Leachability

    KW - Solid-phase sulfide material (SSM)

    KW - Sulfate reducing bacteria (SRB)

    KW - Toxicity characteristic leaching procedure (TCLP)

    KW - Arsenic

    KW - arsenic

    KW - dissolved oxygen

    KW - ferric hydroxide

    KW - iron

    KW - nitrogen

    KW - sulfate

    KW - sulfide

    KW - water quality

    KW - water treatment

    KW - adsorption

    KW - analytic method

    KW - article

    KW - concentration response

    KW - dissolution

    KW - evaluation

    KW - extraction

    KW - leaching

    KW - oxidation

    KW - reduction

    KW - solid

    KW - solubility

    KW - sulfate reducing bacterium

    KW - Air

    KW - Bioreactors

    KW - Drug Toxicity

    KW - Ferric Compounds

    KW - Hazardous Waste

    KW - Oxidation-Reduction

    KW - Porosity

    KW - Sulfur-Reducing Bacteria

    KW - Time Factors

    KW - Water Pollutants, Chemical

    KW - Water Purification

    KW - Water Supply

    M3 - Article

    VL - 60

    SP - 254

    EP - 265

    JO - Chemosphere

    JF - Chemosphere

    SN - 0045-6535

    IS - 2

    ER -