Technologies

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Technologies for Radon Radionuclide Removal
Tom Sorg U. S. Environmental Protection Agency
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Radionuclides
Radon Rn Radium Ra Uranium U
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Radon - 222
Radioactive Element in the Uranium 238 decay
series Decay product of Ra 226 Alpha
emitter Half life of 3.8 days
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Radon - 222
Rn 222 3.8 days Po 218 3 min Pb 214
27 min Bi 214 20 min Po 214 1.6x10-6
sec Pb 210 20 years
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Radon - 222
Gas Naturally occurring ground water
contaminant Proposed MCL - 300 pCi/L MMM
Program - 4000pCi/L (AMCL)
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Radon Removal Technology

• Aeration (BAT) 70 - 99
• GAC 80 - 99

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Aeration Technology
Packed tower 90 -99 High performance PP 90 -
99 Diffused bubble 70 - 99 Tray 80 - 90
Spray 80 - 90 Mechanical surface gt90
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GAC Technology Very Small Systems/ POU/POE
GAC 80 - 99 High EBCT
requirements Potential radiation exposure
problems Potential waste disposal problems
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Radium
Ra 224 Thorium series Alpha emitter Half life
of 3.6 days Ra 226 Uranium series Alpha
emitter Half life of 1620 years
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Radium

• Ra 228
• Thorium series
• Beta emitter
• Half life of 6.7 years

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Radium
Cation Ra2 Naturally occurring ground
water contaminant Current MCL - 5 pCi/L
(Ra 226 Ra 228)
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Radium
Chemistry is similar to calcium and magnesium
(hardness elements)
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Radium Removal Technology

• Cation Exchange 65 - 95
• Lime Softening 80 - 95
• Membrane Processes 90 - 99
• Selective Complexers 97

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Radium Removal Technology
Cation Exchange - Selectivity Sequence Ra2 gt
Ba2 gt Ca2 gt Mg2 gt Na2 gt H2 Hardness can be
used as a surrogate measurement of radium
breakthrough
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Uranium
U 238 Uranium series Alpha emitter Half life
of 4.5x109 years U 234 Uranium series Alpha
emitter Half life of 2.5x105 years
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Uranium

• U 235
• Actinium series
• Alpha emitter
• Half life of 7.1x106 years

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Uranium
Cation/Anion/Neutral depending on pH Naturally
occurring ground water contaminant Curren
t MCL - none Proposed MCL in 1991 20 ug/L
30 pCi/L
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Uranium in Water Chemical Forms
pH lt 2.5 Cation - UO2 pH lt 2.5 -
7 Neutral - UO2(CO3)0 pH 7 - 10
Anion - UO2(CO3)-2 - UO2(CO3)-4

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Uranium Removal Technology

• Coagulation/Filtration 80 - 95
• Lime softening 85 - 99
• Anion Exchange 90 - 99
• Activated Alumina 90 - 99
• Membrane processes 90 - 99

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Uranium Removal Technology
Anion Exchange - High U capacity Treat 10k -100k
bed volumes Capacity sulfate dependent
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Uranium Radium Removal Technology
Cation /Anion Exchange System Ra 100 -1500 BVs U
10k -100k BVs Adjust amount of cation / anion
resin Optimum mixture - 10 anion 90
cation
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Gross Alpha, Beta Particle Photon Emiters
MCLs Gross alpha - 15 pCi/L (including Ra
226) Beta particle photon emitters - 4
mrem/year
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Gross Alpha, Beta Particle Photon Emiters BAT
Gross alpha Reverse osmosis Beta
particle Ion Exchange photon emitters
Reverse Osmosis
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SUMMARY

• Radon, radium uranium are naturally occurring
  contaminants usually occurring in ground water.

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SUMMARY - RADON

• Aeration and GAC are effective treatment
  technologies for radon.
• Of the two technologies, only aeration will be
  listed as a BAT and likely be the technology of
  choice in almost all cases.
• GAC will likely be considered for only very small
  systems and for POU/POE.

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SUMMARY - RADIUM

• All technologies effective for hardness removal
  are generally effective for radium removal.
• Cation exchange, lime softening and reverse
  osmosis are the technologies currently being
  applied for radium removal.

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SUMMARY - URANIUM

• Most conventional technologies have some
  capability for uranium removal.
• Anion exchange has been successfully applied for
  uranium removal from small ground water systems.

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Tom Sorg USEPA Cincinnati, OH 45268 513-569-7370
sorg.thomas_at_epa.gov