h. weigand, c. gemeinhardt & c. marb€¦ · © lfu / josef-vogl-technikum / 2005 introduction...

© LfU / Josef-Vogl-Technikum / 2005

STARNET Conference 12. – 13.04.2005 Cambridge, England UK

Stabilising inorganic contaminants in soils: Considerations for the use of smart additives

H. Weigand, C. Gemeinhardt & C. Marb

Funded by


IntroductionMethods/EvaluationResults

Background

Contaminant stabilisation

Treatment of contaminatedsoils in the framework of

economic, ecologic & regulatory

interests

R&D-Project:„Methods and evaluation

criteria“

Compliancewith standards

(regulators)Technology

(market actors)



Attributes of ‘smart additives’

Promote formation of stable contaminant pools

Avoid competitive release/secondary contamination

Reduce contaminant bioavailability

Effective in the per mil to lower percent range

React fast relative to pore water residence times

Conserve soil hydraulic properties



Physico-chemical and biological tests

Additive testing with spiked solutions

Sequential extractions – contaminant binding form analysis

Batch equilibrium experiments with stabilised/original soil

Bioavailabilty/growths inhibition tests

Column experiments, lab- (V0 ~ 2 L) & pilot-scale (V0 ~ 2.000 L)

Monitored field trials



Suitability of additive

Contaminant removal from spiked solution by natural Zeolite

0

50

100

150

200

250

300

0 2 4 6 8

Solution concentration [meq/L]

Zinc Langmuir isotherm

0

50

100

150

200

250

300

0 2 4 6 8


Lead measured Langmuir isotherm

0

50

100

150

200

250

300

0 2 4 6 8


Solid

pha

se c

once

ntra

tion

[meq

/kg]

Copper measured Langmuir isotherm

measured


IntroductionMethods/EvaluationResults Accessibility of contaminant pools

Binding form analysis by sequential extraction

0

10

20

30

40

Zinc

frac

tion

[%]

0

10

20

30

40

Mobile

Exchangeable

Mn-oxides

Organic matter

Amorphous Fe-oxides

Crystalline Fe-oxides

Residual

Ars

enic

frac

tion

[%]

As-contamination

Zn-contamination

?


IntroductionMethods/EvaluationResults Applicability to mixed contamination (I)

Batch-equilibrium test, L/S 10: Firing range soil + Fe-rich additives(DeFerrisation Sludge, Goethite)

0

2

4

6

8N

one

2% 5% 8% 2% 5% 8%

Non

e

2% 5% 8% 2% 5% 8%

Non

e

2% 5% 8% 2% 5% 8%

DFS Goethite DFS Goethite DFS Goethite

Solu

tion

conc

entr

atio

n [m

g/L]

Lead AntimonyCopper


IntroductionMethods/EvaluationResults Applicability to mixed contamination (II)

Batch-equilibrium test, L/S 10: Firing range soil + P-fertiliser additives(DiAmmonium Phosphate, Triple Super Phosphate)

0

2

4

6

8N

one

0.5%

1.0%

2.0%

0.5%

1.0%

2.0%

Non

e

0.5%

1.0%

2.0%

0.5%

1.0%

2.0%

Non

e

0.5%

1.0%

2.0%

0.5%

1.0%

2.0%

DAP TSP DAP TSP DAP TSP

Solu

tion

conc

entr

atio

n [m

g/L]

Lead AntimonyCopper


IntroductionMethods/EvaluationResults Applicability to mixed contamination (III)

Additive-induced modification of solution chemistry: Indirect copper mobilisation

5

6

7

8

9

0.5% 1.0% 2.0% 0.5% 1.0% 2.0%

None DAP TSP

pH o

f bat

ch e

xtra

ct [–

]

0

10

20

30

40

DO

C c

once

ntra

tion

[mg/

L]

pH DOC

pH⇑

DOC⇑

Cu⇑

pH⇑

DOC⇑

Cu⇑


IntroductionMethods/EvaluationResults Response of biota

Growth inhibition of Lemna minor by batch extracts of stabilised smelter soil

0

100

200

300

400

500

600

Day 0 Day 4 Day 7

Lem

na fr

ond

area

[mm

²]

Control solution Zeolite fine Zeolite coarse Goethite Original soil Potassium dihydrogen phosphate Iron(II)sulphate Phosphoric acid

Additive Σ Cd, Zn, Pb [mg/L]

Zeolite fine 0.28

Zeolite coarse 0.25

Goethite 0.30

Untreated 0.31

KH2PO4 0.18

FeSO4 1.18

H3PO4 17.87


IntroductionMethods/EvaluationResults Effectivity: (Transient) flow conditions

FeSO4-treated Emerald Green site: Stabilisation vs. mobilisation

0

10

20

30

40

50

60

0 5 10 15 20

Pore volumes exchanged [–]

Ars

enic

[mg/

L]

Untreated Treated

0

2

4

6

8

10

0 5 10 15 20

Pore volumes exchanged [–]

Cob

alt,

Nic

kel [

mg/

L]

Untreated Co Treated Co Untreated Ni Treated Ni

2nd irrigationperiod

2nd irrigationperiod


IntroductionMethods/EvaluationResults Contaminant pools

Shift of As binding form pattern induced by FeSO4-treatment

After treatment

Before treatment

0

10

20

30

40

Mobile

Exchangeable

Mn-oxides

Organic matter

Amorphous Fe-oxides

Crystalline Fe-oxides

Residual

Ars

enic

frac

tion

[%]

0

10

20

30

40


IntroductionMethods/EvaluationResults Soil hydraulic properties

0.0

0.2

0.4

0.6

0.8

1.0

0 100 200 300Time [min]

Dim

ensi

onle

ss tr

acer

con

cent

ratio

n

Untreated observed Untreated fit Treated observed Treated fit

Dispersivity: tracer breakthrough

+ saturated conductivity

+ soil water retention curve


Conclusions

Screening for non-target componds: Adverse side effects

Binding form pattern: Pre- and post-treatment benchmark

Bioassays: Combined effects of contaminant and additive

Transport studies: Applicabilty under dynamic conditions

Identifying ‘smart additives’ requires array of tests

h. weigand, c. gemeinhardt & c. marb€¦ · © lfu / josef-vogl-technikum / 2005 introduction...

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