B

.

babcock

& wilcox nuclear operations

group2016mt.athosroadIIynchburg,Va24505-5447usaphone434522.6000fax434.522.6805bwww.babcock.com July

27, 2009 Mr. David Friedman U.S. Environmental

Protection

Agency,

Region

Ill Land

& Chemical

Division

3LC20 1650

Arch Street Philadelphia,

PA 19103-2029 Ref: Petition

to Delisting

of Hazardous

Wastes (Petition)

that

was submitted

on February 21, 2003 Dear

Mr. Friedman: B&W

is providing

an update

to the referenced

petition.

B&W

has reviewed

a early internal development

work report

related

to the solubility

of Calcium

Fluoride

filter

cake

and

the technical

literature

to reference

a Calcium

Fluoride Solubility Equilibrium

Product Constant (Ksp).

A white

paper

on Calcium

Fluoride

Solubility

is attached. After

you have

had

an opportunity

to review

the information,

I would

like

to discuss

it with you

and possibly

setup

a meeting

to review

the status

of the delisting.

Should

you have any questions,

please

give

me

a call

at (434) 522-6677. Sincerely, John

M. Storton Senior Advisory

Engineer Babcock

& Wilcox Nuclear Operation

Group cc

DC Ward

RL Coats

N Whitten

LR Morrell W

H Anderson

JT Howard

File 3-33473 babcock

& wilcox nuclear operations

group,

inc.,

a Babcock

& Wilcox companyCalciumFluorideSolubilityThesludgeinB&W’sFinalEffluentPonds(FEPs)originatedfromsuspendedsolidsmeasuredastotalsuspendedsolids(TSS),carriedoverfromtheneutralizationofradioactiveandindustrialwastewaters.TheindustrialwastewatersincludeeffluentfromaprocessthatVirginiaDepartmentofEnvironmentalQuality(DEQ)consideredtogeneratealistedF006sludge.B&WsuccessfullydelistedthenewlygeneratedF006filtercakesolidsin2000.Thus,thecurrentlygeneratedfiltercakesolidsthataredischargedintothepondsarenolongerclassifiedbytheDEQasanF006waste.In2008B&WcontractedfortheremovalofthesludgeintheFEPsanditsdispositionasamixedwasteatalicenseddisposalsite.Nearlyalloftheapproximately13,200cubicyardsofsludgeinthepondswasremoved,leavingonlyabout150cubicyards.Thismemoexplainswhytherelativelyinsolublefluorideintheresidualsludgedoesnotposeathreattogroundwaterquality.B&W’swastewaterscontainspentnitricandhydrofluoricacid.Thelow-levelradioactiveandnon-radioactivewastewatersareneutralizedinseparatetreatmentsystems.Mostoftheprecipitatedsolidsareremovedusingfilterpressesandsenttodisposalaseitheralow-levelradioactivewasteorindustrialwaste.OnlyminorconcentrationsofsuspendedsolidsaredischargedtotheFEPs.B&W’sVPDESpermitallowsforthedischargeofamonthlyaveragefluoridemassof15Kgperdaywithamaximumof30Kg.B&WisincompliancewithitsVPDESpermitconditions.CurrentlyB&W’sneutralizationoperationusesacombinationoflime(Ca(OH)2)andsodiumhydroxide(NaOH).Thesodiumhydroxideisusedtoneutralizetheacidity,andlimeisaddedinastoichiometricratiobasedonthemeasuredfluorideconcentrationinthespentacidsolutiontooptimizeremovaloffluorideviacalciumfluoride(CaF2)precipitation.CaF2isanioniccompoundconsistingofcalciumandfluorinethathasaverylowsolubility.Itoccursnaturallyasthemineralfluorite(alsocalledfluorspar)andisminedasacommercialsourceoffluorine.Fluorideconcentrationsinwaterarelimitedbyprecipitationofthismineral,whichoccursbythereaction:2F+Ca2-*CaF2Atequilibrium,thefluorideconcentrationiscontrolledbythesolubilityconstraint:=[Ca2]xwhereisthefluoritesolubilityproduct,equalto1.64x10”at25°C,andthevariablesinbracketsarethemolarconcentrations(moles/liter)ofcalciumandfluoride.Thesolubilityoffluoridethusvariesinverselywiththesquarerootofthecalciumconcentration,whichcanbeexpressedas:[F]=

/\![Ca]B&WCaF2Solubility1of57/27/2009AplotoffluoridesolubilityasafunctionofcalciumconcentrationisprovidedinFigure1.Attachment1providesreferencesassociatedwithcalciumfluoridesolubilityproduct.Thesolubilitycanbehighifcalciumconcentrationsarelow,butfluorideconcentrationswillremainbelowtheEPAMCLof4mg/Laslongasthecalciumconcentrationremainsabove—20mg/L.Calciumconcentrationsinwateraftercontactingthesludgeareexpectedtobewellabove20mg/Lbecauseofthepresenceoflimeandcalciumcarbonate,whicharesolublemineralsthataremajorcomponentsofthesludge(discussedbelow).Thesecompoundsshouldmaintaincalciumconcentrationswellabove20mg!L,whichwouldpreventfluorideconcentrationsfromexceeding4mg/L.Fluoridepresentinthesludgeisthusnotpredictedtoimpactgroundwaterbecauseofthehighsolublecalciumcontentofthesludge.TheB&WsolidsthataredischargedtotheFEPshaveacomplexchemicalcompositionwhichispresentedinTable1.B&Wcollectedsamplesofthesludgeforanalysistosupportdevelopmentofawasteprofileforthematerial.ThequantityoflimeusedintheneutralizationprocesshasvariedhistoricallyatB&W,fromlimebeingthesolechemicalusedinneutralizationpriorto1992,tothecurrentpracticeofaddinglimeinastoichiometricratiobasedonthefluorideconcentration.ThecompositiondatapresentedinTable1arebasedonneutralizationbeforelimewasstoichiometricallyadded.Asaresult,thereisexcesscalciumhydroxideinthefiltercakesolids.Table1ChemicalCompositionofFEPSludgeChemicalConcentrationChemicalConcentrationComponent-Component—CalciumFluoride-0-40%CalciumCarbonate5—%ronHydroxide-10-20%—CalciumHydroxide-0-15%—zirconium2-20%-{alogenicOrganic4ydroxide-(HOC)—Compounds(Sumot\iuminum10-15%helistofHOCs.)-lydroxideIn1979,B&Wconductedwastewatertreatmentpilotplantscaletestsforaproposedcommercialnuclearfuelplant.CalciumfluoridefiltercakewasteisgeneratedfromtheB&WCaF2Solubility2of57/27/2009plant’s

waste

water treatment

system.

The testing

was conducted

to address questions associated

with

the suitability

of land disposal

of CaF 2

filter

cake, generated

from acidic wastewater neutralization.

The

two constituents

of concern

in the filter

cake

are

the

low levels

of enriched

uranium

and fluoride.

The testing investigated

the potential

release

of fluoride

and uranium

to groundwater.

(“Testing

of Calcium

Fluoride

as

a Terminal

Waste Storage Material— Final Report”,

B&W Report Number

LR: 79:2000-01:1,

Dr.

LA Smith, December

20, 1979.) The B&W

pilot

plant

tests generated

a quantity

of CaF 2

filter

cake

that

was

used

for

the long

term

leach

tests.

The CaF 2

filter

cake

was dried

at 105

°C, ball-milled

to pass through

a

16 mesh

screen

and mixed,

then

four random

samples

were collected

for evaluation.

The samples

were analyzed

for specific compounds

and

the composition

data is provided

in Table

2. Long

term

leach

tests

were performed

to measure

of the leach resistance

of the CaF 2

filter cake. Long-term

leach

test samples

were prepared

using polyethylene

drying

tubes

(15.2 cm long

with

a diameter

of

1.6

cm with

a Pyrex

wool bottom

plug). Different

mixtures of soil,

soil plus

CaF 2

filter

cake,

as well

as just

CaF 2

filter

cake

were

used

in the colunm tests.

Each week-day

5 ml

of deionized

water

was added

to each

tube.

The

flow

rate

of the water through

the tube

was

not controlled.

The effluent

from

the tubes

was collected and periodically

sampled.

The long-term

leach

test results

are presented

in Table

3. Table

2 CaF 2 Filter

Cake Analysis

Results Sample

No.

CaF 2

CaSiO 3

CaCO 3

Ca(OH) 2

KOH %

%

%

%

% CaF 2

-1

46.2

21.0

6.0

13

1.8 CaF 2

-2

49.1

11.6

5.8

25.7

2.2 The CaF 2 column

data

in Table

3 indicates

only

trace concentrations

of fluoride

is present in the effluent.

These

results

can

be explained

by calcium

being contributed

by

the other slightly

soluble

calcium compounds

in the filter

cake (Table

2).

The Soil+CaF 2

column data indicates

that even

less fluoride

is present

in the effluent

when

soil

is added

to the filter

cake.

This additional

removal

process

may

be

ion exchange

of

F ions

with hydroxyl

(OTT)

ions present

in soil minerals

that contain hydroxyl

groups.

Fluoride

ions will exchange

with

OW

ions

that

are present

as structural components

in common

soilforming

minerals

such

as clays, amphiboles,

micas,

and aluminum hydroxides.

These exchange

reactions

may

be contributing

to the immobilization

of fluoride

in the

soil. B&W

CaF 2 Solubility

3 of

5

7/27/2009Table3LongTermLeachTestFluorideResults-I00E0LI*Lasttwovaluesnotincluded.TimeIntervalSoilSoil+CaF2CaF2FilterCake(days)(ppmF)(ppmF)(ppmF)00.30.41.43790.30.81.43960.10.80.74270.10.81.54400.10.81.14740.10.61.65170.10.71.45370.1<0.11.15640.1<0.11.3Mean0.1440.700*1.28StandardDeviation0.08820.1528*0.273Underconstantexposuretowaterfor564days,onlyasmallportionofthefiltercakedissolvedandtheconcentrationoffluorideintheeffluentremainedverylowthroughoutthetest.ThisimpliesthatfluorideintheCaF2filtercakehasaverylowsolubilitythatlimitsitsconcentrationinwatercontactingthematerial.Thesetestresults,supportedbysolubilitycalculations,supporttheargumentthatthefluoridepresentintheFEPsludgeisimmobileandwillnotimpactgroundwater.Figure1.FluorideSolubilityasaFunctionofCalciumConcentrations1614121086420050100150200250300350400Calcium(mg/I.)B&WCaF2Solubility4of57/27/2009AttachmentICalciumFluorideSolubilityProduct—SolubilityEquilibriumConstant(K)valuesforcalciumfluoride(OaF2)areshowninthetablebelow.Thevalueof1.64x10h1fromtheEQ3/6database,whichisinthemiddleoftherangeofpublishedvalues,wasusedtoproducethecurve.ThisrelatestoaCaF2concentrationinsolutionof1.28E-9gramsperliter.TheactualconcentrationofCaF2insolutionisdependentonavarietyofparametersincludingconcentrationofCalciumandotherionsinsolution.CalciumFluorideReference1.64x10h1EQ316Database3.98x10h1PennStateDatabase1.10x10h1Nordstrom&Jenne,19773.16x10h1Krauskopf,19671.10x10h1MINTEQDatabase2.51x10”PHREEQCDatabase2.63xi011Brown&Robertson,1977B&WCaF2Solubility5of57/27/2009