Aquifer thermal energy storageResearch of the impacts of ATES on groundwater quality

Aquifer thermal energy storage

Development of ATES in Holland

Research questions and projects

- What are the risks of ATES systems on groundwater quality (chemical, microbiological and physical)?

- Where can we allow what type of ATES systems?

Two research projects:- Matthijs Bonte: hydrochemical impacts (BTO)- Philip Visser: physical impacts (TTiW)

Approach and methods

- Monitoring ATES systems at 3 sites (mostly 7-17°C)

- Laboratory experiments (5-60°C)

- Numerical modelling (Modflow/Mt3D,Phreeqc)

Sampling and field locations

Field ATES system – Eindhoven: Monitoring program 2005-2012 (Brabant Water)

Key question: what effects are visible at field scale?

ATES siteDrinking water

Pumping station

Field data – EindhovenDepth profiles of ambient groundwater quality

-ATES system is realized in Sterksel aquifer

-Vertical redox zonation: removal of NO3, SO4; followed by appearance of CH4

Field data Eindhoven: Water quality patterns in ATES wells

Ambient concentration range

Modflow-MT3DModelling of water quality pertubations

Hydrogeology Simulated sulfate concentration

Laboratory investigations

Aim: - Detailed analyses of Hydrochemical changes

-Investigate more extreme T

- Investigate reaction kinetics at different temperatures

Types of lab experiments

-Test 1: Continuous flow test with 1 day residence time at 5,11,25 and 60ºCin three sediment samples from the Sterksel formation focus equilibrium reaction (sorption, mineral interaction)

-Test 2: Incubation test with increasing residence time (1-35d) focus kinetically restricted (redox) reactions

-Text 3: Temperature ramping test with 5d residence (T = 5 to 80ºC) focus kinetically restricted (redox) reactions

Collection of soil cores

-Percussion drilling -Ackerman coring-Working water sparged with N2-Transport in N2 filled cooling box

Sampling of influent water

Installation in lab

Results of 1 day leaching test: comparing concentration at 5, 25 and 60ºC with 11ºC

Leaching behavior 

Geochemical  

Temperature level

5ºC 25ºC 60ºC

Substances significantly thermally influenced (p<0.01) in all three experiments,

Substance present in sediment

As DOC, PK, SiAs, Mo, V

Substance not present in sediment above detection limit

Be

Not analysed F, Li

Organic matterSilicatesTrace elements

Results of 1 day leaching test: comparing concentration at 5, 25 and 60ºC with 11ºC

Leaching behavior 

Geochemical  

Temperature level

5ºC 25ºC 60ºC

Substances significantly thermally influenced (p<0.01) in all three experiments,

Substance present in sediment

As DOC, PK, SiAs, Mo, V

Substance not present in sediment above detection limit

Be

Not analysed F, Li

Leaching behavior not significantly influenced by temperature in all three experiments

Substance present in sediment

Alkalinity, SO4, Na, Mg, Sr, Ca, Fe, Mn, Al, Ba, Co, Cr,

Cu, Eu, Ho, Ni, Pb, Sb, Sc, U, Yb, Zn

Substance not present in sediment

Ag, Bi, Cd

Not analysed Br, Cl, B, In, Tl

Substance below detection limit in reference and testing temperature

Substance present in sediment

Ga, La, Th

Substance not present in sediment

Bi, Se

Organic matterSilicatesTrace elements

Most relevant for drinking water: Arsenic (but also in B, Mo, P)

Arsenic concentration as function of temperature

0

0.01

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0 10 20 30 40 50 60 70

T(degC)

Dis

so

lve

d A

s (

mg

/l)

Exp A

Exp B, Fe=3.2mg/l

Exp B, Fe=0.8mg/l

Exp C

Norm WLB

Mechanism (oxy)anion desorption from Fe-oxides due to

- primarily temperature increase

- DOC and P release (competition for sorption sites)

Arsenic sorption: described with Freundlich sorption and van ‘t Hoff equation

Sorption isotherm (Freundlich curve)

nFCKQ /1

Sorption temperature dependence:Van ‘t Hoff relation

ΔH points to Exothermicsorption (decreasing with T↑)

Literature range ~

-25 to -110kJ/mol

Van ‘t Hoff plot

R

S

RT

HKd

ln

Field evidence of As and B leaching?

RIVM PB437-2

0.02

0.025

0.03

0.035

0.04

Aug-10 Nov-10 Feb-11 May-11 Sep-11 Dec-11 Mar-12 Jul-12

[As]

mg/

l

11.5

11.9

12.3

12.7

13.1

13.5

T(ºC

)

As Temp with data logger Manual T-readings

Heuvelgallerie Eindhoven (multiple MWs)

y = 0.4323e0.142x

R2 = 0.5273

0

5

10

15

20

25

30

0 5 10 15 20 25

Temp (degC)

B (u

g/l)

Result batch experiment: clear impact on sulfate reduction rate and organic carbon mobilization

01234

5678

0 10 20 30

Residence time (day)

DO

C (

mg

/l)

0123456789

10

0 10 20 30

Residence time (day)

SO

4 (m

g/l) 5 degC

12 degC

25degC

60degC

Influent

Temperature dependence of sulfate reductiondescribed with Arrhenius equation

Arrhenius plot SO4 reduction

-4

-3

-2

-1

0

1

2

3

4

2.9 3.1 3.3 3.5 3.7 3.9

1000/T(1/K)

Ln

k (

nm

ol/l

/d)

Exp A

Exp B

Exp C

Linear(Exp B)Linear(Exp A)Linear(Exp C)

Arrhenius equation:

Ea = 38-50 kJ/molQ10 = 1.7 - 2

Results temperature ramping reveals a ‘double peak’ pointing to 2 microbiological pop.

0

1

2

3

4

5

6

7

0 10 20 30 40 50 60 70 80 90

T(°C)

Eff

luen

t su

lfat

e co

nce

ntr

atio

n (

mg

/l)af

ter

5 d

ay r

esid

ence

tim

e

Topt 1 Topt 2

Linear increase in dissolved organic carbonbut not in methane

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 20 40 60 80 100 T(°C)

DO

C (

mg

/l)

-10

0

10

20

30

40

50

60

CH

4 (u

g/l

)

CH4

DOC

Influent DOC

Influent CH4

-Biological methane production, no methane producers at 70ºC?-DOC shows no correlation with SO4 reduction rate (DOC is often considered intermediate in Sulf.Red.)

Field evidence of DOC and CH4 increase?(Heuvelgallerie ATES 30ºC)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 20 40 60 80 100 T(°C)

DO

C (

mg

/l)

-200

0

200

400

600

800

1000

CH

4 (u

g/l

)

CH4- LAB

DOC- LabDOC- Field

CH4-f ield

Mapping microbiological community: TRFLP fingerprinting, distinctly different at 60ºC

96.2

87.9

85.6

77.1

96.5

86.1

69.8

81.4

64.7

42.3

40.3

30.3

43.0

16.6

T-RFLP HhaI

10095908580757065605550454035302520

T-RFLP HhaI

4.00E-3

6.00E-3

0.01 0.01 0.03 0.06 0.10 0.15 0.30 0.60 1.00 1.50 3.00 6.00 10.00 15.00 30.00 60.00 70.00 100.00

120.00

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360.00

380.00

400.00

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440.00

460.00

480.00

500.00

520.00

540.00

600.00

bp

M112677

M112678

M111863

M111864

M112679

M112681

M112682

M112683

M111865

M111866

M111867

Pos. Controle 2-8-2011

M112680

blanco 2-8-2011

M112684

2011-08-01

2011-08-01

2011-05-31

2011-05-31

2011-08-01

2011-08-01

2011-08-01

2011-08-01

2011-05-31

2011-05-31

2011-05-31

2011-08-01

2011-08-01

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

Water Kern 1 (5°C)

Water Kern 2 (12°C)

influent

kolom1

Water Kern 3 (25°C)

Zand K1 (20-25cm)

Zand K2 (20-25cm)

Zand K3 (20-25cm)

kolom2

kolom3

kolom4

Water Kern 4 (60°C)

Zand K4 (20-25cm)

5

12

12

5

25

5

12

25

12

25

60

60

60

96.2

87.9

85.6

77.1

96.5

86.1

69.8

81.4

64.7

42.3

40.3

30.3

43.0

16.6

T-RFLP HhaI

100

95908580757065605550454035302520T-RFLP HhaI

4.00

E-3

6.00

E-3

0.01

0.01

0.03

0.06

0.10

0.15

0.30

0.60

1.00

1.50

3.00

6.00

10.00

15.00

30.00

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70.00

100.0

0

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0

220.0

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240.0

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320.0

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340.0

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360.0

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380.0

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400.0

0

420.0

0

440.0

0

460.0

0

480.0

050

0.00

520.0

054

0.00

600.0

0

bp

M112677

M112678

M111863

M111864

M112679

M112681

M112682

M112683

M111865

M111866

M111867

Pos. Controle 2-8-2011

M112680

blanco 2-8-2011

M112684

2011-08-01

2011-08-01

2011-05-31

2011-05-31

2011-08-01

2011-08-01

2011-08-01

2011-08-01

2011-05-31

2011-05-31

2011-05-31

2011-08-01

2011-08-01

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

VU lab

Water Kern 1 (5°C)

Water Kern 2 (12°C)

influent

kolom1

Water Kern 3 (25°C)

Zand K1 (20-25cm)

Zand K2 (20-25cm)

Zand K3 (20-25cm)

kolom2

kolom3

kolom4

Water Kern 4 (60°C)

Zand K4 (20-25cm)

5

12

12

5

25

5

12

25

12

25

60

60

60

Temperature

DNA fragmentsCluster analysis

PHREEQC modelling of 1-day residence time column experiments

Key question:-Can the inferred chemical processes explain the observed quality trends

Processes included:-Cation exchange-Equilibrium with carbonate solid solution-Kinetic dissolution of k-feldspar-Surface complexation of trace elements to goethite

Model optimised with PEST (Marquardt-Levenberg method)

Modelling results: pH, Ca, Mg, Sr and alkalinity:89% CaCO3, 10%(CaMg)CO3, 1%SrCO3

Modelling results: Si and KExplained by incongruent K-feldspar dissolution

Decreasing rate with time due to precipitation of secondary minerals

Modelling results: As, B, P, DOC, Mo

Expansion of PHREEQC / Dzombek & Morel database with ΔH values for surface complexation

Conclusions PHREEQC modelling

Test results can be simulated with combination of cation exchange, carbonate & K-feldspar dissolution and surface complexation

Constraint of the model is for some parameters quite poor, especially surface complexation, e.g.: ΔHAs = -38.5 ±13.3 kJ/mol (van ‘t Hoff plot: -42±2kJ/mol)

ΔHMo= -36.3 ± 32.2 kJ/mol

ΔHB = -14.9 ± 14.1kJ/mol (van ‘t Hoff plot: -22±4kJ/mol)

Due to high correlation between ΔH values (R2>0.8) Surface complexation describes competition between species, different parameters are closely linked

Conclusions: effects of ATES on water quality

Field data:-Mixing of vertical stratified water qualities dominates effects measured in field

-ATES induced mixing potentially increases vulnerability of phreatic pumping stations

Conclusions: effects of ATES on water quality

Laboratory data:-Sorption of heavy metals is strongly temperature dependent (but probably reversible)

-Sulfate reduction rate breakdown in aquifers appears to follow Arrhenius (Q10 1.7-2) but more temperature detail shows 2 maxima: ~40 and 70ºC

Field data:-Mixing of vertical stratified water qualities dominates effects measured in field

-ATES induced mixing potentially increases vulnerability of phreatic pumping stations

General conclusions

-ATES not in capture zone / protection zone’s of vulnerable pumping stations

General conclusions

-ATES not in capture zone / protection zone’s of vulnerable pumping stations

-In other area’s, impacts are probably acceptable and reversible

General conclusions

-ATES not in capture zone / protection zone’s of vulnerable pumping stations

-In other area’s, impacts are probable acceptable and reversible

-At much higher temperatures (>25ºC), ATES impacts reactive (buffering) capacity of aquifer (SOM degradation)

General conclusions

-ATES not in capture zone / protection zone’s of vulnerable pumping stations

-In other area’s, impacts are probable acceptable and reversible

-At much higher temperatures (>25ºC), ATES drastically impacts reactive (buffering) capacity of aquifer

-High T ATES is still an option, but only in aquifers where irreversible impacts are acceptable (high salinity aquifers, high vertical anisotropy)

Questions?