Selenium Removal from Mine Waters
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Selenium Removal from Mine Waters Raymond J. Lovett, Ph.D. Environmental Chemist ShipShaper, LLP PowerPoint PPT Presentation


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Selenium Removal from Mine Waters Raymond J. Lovett, Ph.D. Environmental Chemist ShipShaper, LLP Morgantown, WV. National Mine Land Reclamation Center, West Virginia University United States Office of Surface Mining Magnum Coal Company Catenary Coal. SUPPORT. [Se] = 13 ug/L

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Selenium Removal from Mine Waters Raymond J. Lovett, Ph.D. Environmental Chemist ShipShaper, LLP

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Selenium removal from mine waters raymond j lovett ph d environmental chemist shipshaper llp

Selenium Removal from Mine Waters

Raymond J. Lovett, Ph.D.

Environmental Chemist

ShipShaper, LLP

Morgantown, WV


Support

National Mine Land Reclamation Center, West Virginia University

United States Office of Surface Mining

Magnum Coal Company

Catenary Coal

SUPPORT


Typical southern west virginia mine water

[Se] = 13 ug/L

[Fe] = 0.15 mg/L

[SO4-2]= 980 mg/L

Alkalinity = 235 mg/L as CaCO3

pH = 7.1

Typical Southern West Virginia Mine Water


Problems

Problems

  • Overriding Concern

    • Regulatory limit near 5 ug/L

  • Specific Problems for Treatment

    • Low level of Se

    • Differing chemistries

      • Selenate, SeO4-2, Se(VI)

      • Selenite, SeO3-2, Se(IV)


Selenium removal difficulties

Selenium Removal Difficulties

  • Different dissolved species

  • No direct precipitation chemistries

  • Reduction of selenate is difficult (slow)

  • Sulfate may interfere


Treatment system objectives

Treatment System Objectives

  • Effluent maximally 5 ug/L Se

  • Low installation cost

  • Low operating cost

  • Passive


Demonstrated chemistries

Demonstrated Chemistries

  • Adsorption or co-precipitation by Fe(III) hydroxides

  • Biological (bacterial reduction)

  • Reverse osmosis

  • Reduction by Fe(0)


Reduction with iron metal

Reduction with Iron Metal

  • SeO4-2 +Fe(0) => Fe(II,III) +Se(0)

  • SeO3-2 +Fe(0) => Fe(II,III) +Se(0)


Selenium species on iron

Selenium Species on Iron


Field trial catenary coal

Field TrialCatenary Coal

Test in a real setting

Real, variable input chemistry

Continuous Se Input


Field trial system

Field Trial System


Field trial system1

Field Trial System


Catenary post trial 1

Catenary Post Trial 1


Catenary post trial 2

Catenary Post Trial 2


Catenary post trial 3

Catenary Post Trial 3


Catenary post trial 4

Catenary Post Trial 4


Catenary post trial 5

Catenary Post Trial 5


Reduction with iron metal1

Reduction with Iron Metal

  • Potential

    • Removal of selenate and selenite

    • Passive

  • Problems

    • Iron Oxides/ Dissolved Fe, Mn

    • Exhaustion

    • Passivation

    • Expense (surface area)


Bacterial estimated cost

BacterialEstimated Cost

  • Flow = 285 gpm

  • Capital Cost = $7.2 to $10 million

  • O&M = Unknown


Reverse osmosis estimated cost

Reverse OsmosisEstimated Cost

  • Flow = 200 gpm

  • Capital Costs = $1.2 million

  • O&M = $5.85 million/year


Iron hydroxide estimated cost

Iron HydroxideEstimated Cost

  • Flow = 200 gpm

  • Capital Cost = $0.69 to 1.03 million

  • O&M = $1.39 million/year


Zerovalent iron estimated cost

Zerovalent IronEstimated Cost

  • Flow = 250 gpm*

  • Capital costs = $478,000

  • O&M = $150,000 to $300,000

    * Gravity flow, includes surge


Conclusions

Conclusions

  • Iron metal removes selenate and selenite, but currently requires long contact times

  • Manganese and iron generated

  • Temperature sensitive (?)

  • Less expensive than other methods


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