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Removal of perfluoroalkyl acids from the drinking water production chainChristian Eschauzier and Pim de Voogt.

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Outline

• Introduction

• Sources of PFAA to groundwater

• Behavior of PFAA in drinking water production

• Conclusions

2

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Perfluoroalkyl acids - properties

• Chain length varies nCF2 +F = 3 to 17

• Very persistent, possibly bioaccumulative and toxic.

• Water solubility: 9.5 g/L � high!

• Multiple uses

Acid

hydrophilic

Perfluoroctanoic acid (PFOA)

Very stable bond

Fully fluorinated chain

hydrophobic

Introduction

• PFAA in environmental compartments

• Surface water, biota, air

• Human serum

• Exposure pathways (denHollander, 2010)

• Drinking water(Vestergren, 2009)

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Introduction

Perfluoroalkyl acids in drinking water: Sources, fate and removal.

• Sources: to groundwater and surface waters

• Fate: During treatment

• Removal: Affinity adsorption

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Introduction

6

•PFAA in surface waters

•Surface vs. Drinking water

•Background concentrations:

• low ng/L level e.g. Ericson(2009)

•In surface waters or groundwater contaminated areas: high concentrations

•Unknown concentrations in Dutch drinking water •Info mainly focuses on PFOA and PFOS•Info does not focus on different treatment steps

Takagi, 2008

PFOA

0

50

100

150

200

250

300

350

400

450

Mar-06 Oct-06 Apr-07 Nov-07 Jun-08 Dec-08 Jul-09 Jan-10

Datum

Co

nc

. n

g/L

Hochbehälter „Vogled“

Übergabeschacht Marktl

Hochbehälter Eschelberg

LGL, 206 to 2009

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• Low concentrations in general (ng/L)

• Much less info available

• Sources

• fire fighting practise

• Landfills

• Producing/using companies

• Drinking water treatment less thorough

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Sources to groundwater

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Case study

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Groundwater: Case study

• Chain length dependent behaviour

• PFOS not mobile

• Point source: Landfill

• Diffuse source: Rainwater

• PFOS mobility

• Removal from groundwater…?

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Fate: During treatment

•Drinking water production of Amsterdam•Two sampling rounds •Hydrological retention time taken into account•More than 60 samples analyzed in duplicate over two seasons

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11

F

Drinking

Water

Production

from river

Rhine water

in NL

with sampling

points

Drinkingwater treatment

12Watercycle Research Institute

G

H I

J

Drinkingwater treatment

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PFAA behaviour during DW treatment

•Similar PFAA profile in

the surface water as through

the pre-treatment process

•PFAA present in all samples

• PFBA (52 ng/L max)

• PFBS (42 ng/L max) (in raw water)

Inf.

Lek c

anal

Effl. c

oagula

tion

Effl. r

apid

san

d filtr

atio

n

0

5

10

15

Co

nc.

ng

/L

Afte

r dune

passa

ge

Effl. r

apid

san

d filtr

atio

n

Effl. o

zonat

ion

Infl

GAC fi

ltrat

ion

Effl. F

irst G

AC fi

ltrat

ion

Effl. G

AC fi

ltrat

ion

Drin

king w

ater

0

5

10

PFBA

PFHxA

PFOA

PFNA13

36

28

32

Inf.

Lek c

anal

Effl. c

oagula

tion

Effl. r

apid

san

d filtr

atio

n

0

10

20

30

40

Co

nc.

(ng

/L)

Afte

r dune

passa

ge

Effl. r

apid

san

d filtr

atio

n

Effl. o

zonat

ion

Infl

GAC fi

ltrat

ion

Effl. F

irst

GAC fi

ltrat

ion

Effl. G

AC fi

ltrat

ion

Drin

king w

ater

0

10

20

30PFBSPFHxSPFOS

A B

C D

Results 2GAC filtration

•No removal of PFAA throughout the purification process except for GAC filtration.

•No removal of ≤C8 carboxylic acids and ≤ C5 sulfonic acids

•Filter age dependency of the removal capacity

-100

-80

-60

-40

-20

0

20

Lead PFCALag PFCA

C5 C6 C7 C8 C9 C10

Lead PFSALag PFSA

ALkyl chain length

Rem

oval (%

)

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PFOA

0.1 1 10 1000.1

1

10

100

JapanUSUK

Influent (ng/L)

Eff

luen

t (n

g/L

)

PFOS

0.1 1 10 1000.1

1

10

100

JapanUSUK

Influent (ng/L)

In a broader perspective

Conclusions

• From all tested processes only GAC removes PFAA

• No removal of short chained PFAA• PFBS which is used PFOS substituent

• PFHxA which is partly replacing PFOA

• Margins to existing guidelines are large

• 300 ng/L PFOS + PFOA

• PFBA 7000 ug/L (Wilhelm, 2010)

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Acknowledgments

• EU project PERFOOD (KBBE-227525)

• TTIW Wetsus

• BTO

• Wellington Laboratories

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