assessment and selection of various technical...

Assessment and Selection of Various Technical Grades Zero Valent Irons (ZVIs) for Remediation of Chlorinated

Ethenes for Validating Efficacy of the Rheine Site Permeable Reactive Barrier (PRB), Germany

1

Volker Birke

Faculty of Engineering,

Department of Mechanical, Process and Environmental Engineering Hochschule Wismar – University of Applied Sciences,

Technology, Business and Design, Philipp-Müller-Str. 14, 23966 Wismar, Germany

Volker Birke1, Rahul Singh1, 2, Lothar Vigelahn3,

Sumedha Chakma2, Christine Schuett4, Harald Burmeier4 1 Department of Mechanical Engineering / Process Engineering

and Environmental Engineering, Hochschule Wismar – University of Applied Sciences, Technology, Business and Design, Philipp-Müller-Str. 14, 23966 Wismar, Germany,

2 Department of Civil Engineering, Indian Institute of Technology (IIT) Delhi, Hauz Khas, New Delhi – 110016, India,

3 German Federal Environmental Agency, Wörlitzer Platz 1, 06844 Dessau-Roßlau, Germany,

4 Ostfalia University of Applied Sciences, Braunschweig, Wolfenbuettel, Germany

2

Long-term International Co-operation With

CRC CARE – Already Since 2004!

Expert Exchange

etc. on Remediation

Projects in Australia (2004 – …)

Expert Exchange

etc. on Remediation

Projects in Germany (2004 – …) Federal Republic of Germany

3

Rheine PRB Site – Cross Section • Erected 1998, pilot scale, continuous barrier, 22,5 m long • Two ZVI brands packed / loaded in two separate

segments of overlapping large diameter boreholes • Comprehensively monitored and investigated during the

German PRB R&D Program for PRBs “RUBIN” funded by the Federal Government 2000 – 2012

4 (Source: Mull and Partner (M&P) GmbH,

Germany)

Rheine PRB Site – Details

Set up of Rheine barrier using circular

caisson drilling (1998)

Rheine: Loading a borehole with ZVI

(1998)

Coring of the iron sponge section at

Rheine (Nov, 2001) 5

Startup & Status • Pilot scale - June

1998 • Bench scale: Evaluation of

microbiology – Feb. 2001

• Primary pollutants – PCE; Secondary pollutants – TCE &

cis-DCE

Reactor – 2 Iron types Granular ZVI & Iron sponge

In separate sections Construction -

“Gotthart-Maier” (GGG Iron, brand covered by IPUTEC GmbH & Co. KG, Rheinfelden, Baden-Württemberg): in the field, initially highly reactive for 1 year, constantly degrading PCE > 95 %, however dropped later to around 70 – 90 %. Although column experiments had revealed better results prior to erection of the pilot PRB! 6

“Iron Sponge” (Responge, brand covered by Mull und Partner Ing. GmbH, Hannover): in the field highly reactive over appr. 12 years, constantly degrading PCE > 99 %. Although column experiments revealed poorer results!

GGG Iron Responge

Rheine PRB Performance – Variations in both

Responge and GGG iron

7

Rationale for / Missions of Long Term

Investigations on the Rheine PRB

• Relatively high variability in reactivity of individual varieties of technical grade ZVIs at several RUBIN sites, also in several international studies.

• Systematic investigations of potentially variable reactivities of different production batches of the same technical ZVI brand were missing.

• Thorough explanations were also not available.

8

Primary Objectives of This Study

• Analyze the suitability of various technical grade ZVIs for the long term degradation of PCE in PRBs employing conditions to be encountered at the Rheine PRB site.

• Examine the variations in the PCE degradation efficiency of different production batches of the same technical grade ZVI brand.

• Explore the impact of inorganic parameters on the degradation efficiency of various ZVIs, especially the impact of microbiological activities, within long term column studies.

• Evaluation of short term batch experiments for developing a “Quick Method” for swiftly checking reactivity of ZVI brands and especially different production batches of them each, which may be very helpful for field practitioners, that is, help avoid failures when loading a PRB in the field with a potentially poor ZVI production batch.

9

Long Term Lab Scale Column Experiments

Schematic diagram of column experiment setup in the laboratory

10

Head Module (Gas collector)

Reactor Module (Fe-bed)

II

I

Intake Module (Glass beads)

Space

Free water gas zone

Gas outlet

Outlet

Sampling ports

GW inlet

outlet

• Dimensions: 110 cm long and 20 cm internal

diameter. • Head Module: top 15

cm length comprising the gas collection

chamber • Intake Module:

bottom 5 cm length of the column filled with glass

beads • Reactor Module: middle 90 cm length of the column filled with

ZVI; built by 18 different port & 5 cm between two ports

Details of Various Column Fillings

11

• 13 columns (S) have been installed comprising different Production Batches (PB) of various ZVI Groups:

• Gotthart-Maier Iron (GGG) (purchased from Gotthart-Maier, ,

IPUTEC, Rheinfelden, Germany) • Iron Sponge / Responge (purchased from Mittal Steel GmbH,

Hamburg, Germany) • Würth Iron, metallic shot (purchased from Eisenwerk Würth

GmbH, Bad Friedrichshall, Germany) • Some columns have been filled with GGG iron with 33 % and 50 %

fine gravel dilution.

• Artificially prepared samples of 10 mg/L PCE in deionized water plus inorganic constituents (TIC, sulfate, nitrate, chloride etc.) very well corresponding to the actual Rheine PRB site GW composition (except TOC and microorganisms) have been used in most of the column experiments.

Column Setup, Cooling Chamber @ 10° C

12

Artificial Rheine GW Sample Keg – NO BEER!

Artificial GW Sample Preparation Corresponds virtually Exactly to the Original GW Composition

of the Rheine (Rh) PRB site

13

Parameter Unit Target Values

pH - 7.3 Electrical

Conductivity S/cm 700

Oxygen mg/L <0.2 Na+ mg/L 38.67 K+ mg/L 12

Ca2+ mg/L 100 Mg2+ mg/L 5 Cl- mg/L 40

SO42- mg/L 60

NO3- mg/L 30

TIC mg/L 60 Si mg/L 6

6.0

6.5

7.0

7.5

8.0

0 24 48 72 96 120 144 168 192 216 240 264 288 312 336

pH 6.7

pH 6.5

PH- v

alue

30

40

50

60

70

time in hours

TIC

in m

g/L

pH 6.7

pH 6.5

0 24 48 72 96 120 144 168 192 216 240 264 288 312 336

time in hours

0

2,000

4,000

6,000

8,000

10,000

12,000

0 1000 2000 3000 4000 5000

PCE

in µ

g/L

time in minutes

S7 (GGG PB_1 with 50 % fine gravel, artificial Rh_GW)

13

49

81

135

199

230

247

Pore volume (V/V0)

PCE Degradation in Artificial GW Comparing

First Production Batches of Various ZVIs

14

0

2,000

4,000

6,000

8,000

10,000

12,000

0 1000 2000 3000

PCE

in µ

g/L

time in minutes

S1 (Würth metallic shot, artificial Rh_GW)

20

160

220

332

378

402

468

Sudden drop in conc. at high pore volume due to microbiology

Pore volume (V/V0)

0

2,000

4,000

6,000

8,000

10,000

12,000

0 2,000 4,000 6,000 8,000

PCE

in µ

g/L

time in minutes

S3 (Responge PB_1, artificial Rh_GW)

11

27

57

90

110

147

174

Pore volume (V/V0)

0

2,000

4,000

6,000

8,000

10,000

12,000

0 1,000 2,000 3,000 4,000 5,000 6,000

PCE

in µ

g/L

time in minutes

S4 (GGG PB_1, artificial Rh_GW)

13

55

84

114

139

165

202

Pore volume (V/V0)

Sudden drop in conc. at high pore volume due to microbiology

Findings / Discussion

15

• GGG iron efficiency for degradation of PCE was higher than Würth iron and Responge iron.

• However, Würth iron also showing effective results after long operation (around 350 pore volumes, PV) due to additional microbiological effects (sulfate reduction, production of FeS etc.) commencing not until 350 PV.

• GGG and Responge were also originally (1998) selected, overall, as both cost-effective and sustainable reactive materials for PCE and associated chlorinated compounds degradation at the Rheine site, furthermore, to compare their efficiacy in the field.

• Different production batches of GGG and Responge showed some differences in PCE degradation, however, effective results.

• Chlorinated intermediates, such as TCE and cis-DCE, had also been removed completely from all the column experiments considering GGG and Responge iron and their different production batches.

Evaluation of Microbiological Activities in Various Column Experiments – Sulfate Degradation

16

0

10

20

30

40

50

60

70

80

0 500 1000 1500 2000 2500 3000

Sulfa

te in

mg/

L

average residence time in minutes

S1 (Würth chilled cast iron, artificial Rh_GW)

160

220

325

374

400

4710

10

20

30

40

50

60

70

80

0 1000 2000 3000 4000 5000 6000 7000

Sulfa

te in

mg/

L



11

27

57

86

109

157

166

01020304050607080

0 1000 2000 3000 4000 5000 6000 7000

Sulfa

te in

mg/

L



10

47

87

101

112

121

131

Pore volume (V/V0)

Pore volume (V/V0)

Pore volume (V/V0)

Sudden drop in sulfate conc. confirms microbiological activity

01020304050607080

0 1000 2000 3000 4000 5000

Sulfa

te in

mg/

L



13

28

46

78

96

110

129

Evaluation of Microbiological Activities in Various Column Experiments - Sulfate Reduction

(Cont.)

17

01020304050607080

0 1000 2000 3000 4000 5000

Sulfa

te in

mg/

L



9

28

52

94

130

149

192

01020304050607080

0 1000 2000 3000 4000 5000

Sulfa

te in

mg/

L



14

49

81

127

178

198

229

Pore volume (V/V0)

Pore volume (V/V0)

Pore volume (V/V0)

01020304050607080

0 1000 2000 3000 4000 5000 6000

Sulfa

te in

mg/

L


S4 (GGG PB_1, artificial Rh_GW)

13

56

84

123

150

164

208

Pore volume (V/V0)

0

2,000

4,000

6,000

8,000

10,000

12,000

0 1000 2000 3000 4000 5000

PCE

in µ

g/L

time in minutes

S10 (GGG PB_1 with 50 % fine gravel, artificial Rh_GW with ad. PCE)

4

34

59

86

117

166

208

Comparison of GGG and Responge Reactivity Regarding Original Rheine PRB and Artificial Samples

18

0

2,000

4,000

6,000

8,000

10,000

12,000

0 2,000 4,000 6,000 8,000

PCE

in µ

g/L

time in minutes


11

27

57

90

110

147

174

Pore volume (V/V0)

0

2,000

4,000

6,000

8,000

10,000

12,000

0 1000 2000 3000 4000 5000

PCE

in µ

g/L

time in minutes


13

49

81

135

199

230

247

Pore volume (V/V0) Pore volume

(V/V0)

0

2,000

4,000

6,000

8,000

10,000

12,000

0 2000 4000 6000 8000

PCE

in µ

g/L

time in minutes

S11 Responge PB_1, original Rh_GW with ad. PCE

16

40

79

113

125

130

142

Pore volume (V/V0)

01020304050607080

0 1000 2000 3000 4000 5000

Sulfa

te in

mg/

L


S10 (GGG PB_1 with 50 % fine gravel, artificial Rh_GW with ad. PCE)

24

44

85

122

162

189

204

Microbiological Activity Impacts Differences in Original and Artificial Samples – Due to Sulfate Reduction!

19

0

10

20

30

40

50

60

70

80

0 1000 2000 3000 4000 5000 6000 7000

Sulfa

te in

mg/

L



11

27

57

86

109

157

166

Pore volume (V/V0)

01020304050607080

0 1000 2000 3000 4000 5000

Sulfa

te in

mg/

L



14

49

81

127

178

198

229

Pore volume (V/V0)

0

10

20

30

40

50

60

70

80

0 1000 2000 3000 4000 5000 6000 7000

Sulfa

te in

mg/

L


S11 Responge PB_1, original Rh_GW with ad. PCE

17

30

58

83

110

128

138

Pore volume (V/V0)

Pore volume (V/V0)

Sudden drop in PCE conc. due to microbiological activity

Sudden drop in PCE conc. due to microbiological activity

Findings / Results Microbiology nested PCR direct PCR

sample

enric

hed

volu

me

euba

cter

ia

Deh

aloc

occo

ides

sp.

Des

ulfit

obac

teriu

m s

pp.

Deh

alob

acte

r spp

.

Des

ulfo

mon

ile ti

edje

i

Des

ulfu

rom

onas

spp

.

Met

hano

gens

(mcr

A)

deni

trify

ing

with

nirK

- gen

e

deni

trify

ing

with

NIR

S ge

ne

Ace

toge

nic

(FTH

FS)

Sul

fate

-(DS

R)

S1_P0 100 mL + - - - - - - - - + * +

S1_P5 100 mL + - + * - - - - + - + +

S1_P9 100 mL + - - - - - - + - + * +

S3_P9 100 mL + - - - - - - - - + + *

S3_P17 100 mL + + * - - - - - - - + * + *

S11_P0 100 mL + - - - - - + - - + +

S11_P3 100 mL + - - - - - - + - + +

S11_P9 100 mL + - - - - - - + - + + * positive, but weak signal

Measurements / data: TZW Karlsruhe, Germany – Dr Tiehm

Discussions

21

• At the end of around 1.5 years of column operations, no microbiological activities were detected (no sulfate degradation, no acetate production) in the artificial Rheine GW columns.

• However, just after that a suddenly commencing microbiological sulfate reduction (surprisingly occurring for the artificial Rheine GW in the majority of the columns after a pretty long time of operation), a significantly improved PCE degradation was observed compared to a steadily decreasing reactivity before.

• The original GW columns showed different courses / results than the artificial GW columns for Responge. According to sulfate and PCE analysis, it was observed that in the original Rheine GW columns PCE degradation had also improved due to sulfate reduction compared to Responge columns ran with artificial GW.

• Sulfate reduction and associated improved PCE degradation started earlier in original GW columns rather than in artificial GW columns.

Multiple Batch Experiments Conducted

According to Birke et al., 2014

Birke, V., Schütt, Ch., Burmeier, H., and Friedrich, H.-J. (2014) "Impact of Trace Elements and Impurities in Technical Zero-Valent Iron Brands on Reductive Dechlorination of Chlorinated Ethenes in Groundwater", 87 – 98, in: Naidu, R. and Birke, V. (2014). “Permeable Reactive Barrier: Sustainable Groundwater Remediation”, CRC Press, Boca Raton, U.S.A., 333 p.

22

Combined First Order Kinetic Plots of GGG in Batch Experiments

y = -0.0424x + 2.1464 R² = 0.987

y = -0.0752x + 1.8081 R² = 0.955

y = -0.0963x + 1.6675 R² = 0.9551

y = -0.1152x + 1.1196 R² = 0.9633 -3.0

-2.0

-1.0

0.0

1.0

2.0

3.0

0 5 10 15 20 25 30 35

lnC

, C in

mg/

L

time in hours

GGG PB 1, 15 g GGG PB 1, 30 g GGG PB 1, 40 gGGG PB 1, 60 g Linear (GGG PB 1, 15 g) Linear (GGG PB 1, 30 g)Linear (GGG PB 1, 40 g) Linear (GGG PB 1, 60 g)

Kinetics of PCE degradation employing GGG Iron at different dosages

23

Dependence of PCE Degradation in Column Experiments

24

y = -0.0488x + 2.5566 R² = 0.9791

y = -0.0292x + 2.4134 R² = 0.9742

-1

-0.5

0

0.5

1

1.5

2

2.5

3

0 20 40 60 80

lnC

, C in

mg/

L

time in hours

Dependence of PCE degradation with GGG Iron on various pore volumes

23 Pore Volume 41 Pore VolumeLinear (23 Pore Volume) Linear (41 Pore Volume)

Determining Complex Reaction Kinetics of Batch Results at Various GGG Dosages Using

EasyFit Regression Software

25

Modelling Batch Results Using EasyFit Software, Simultaneous Regression / Fit of Six Batch

Experiments (Cont.)

26

PCE concentration in mmol/L 15 g GGG iron

30 g GGG iron

40 g GGG iron

60 g GGG iron

80 g GGG iron

100 g GGG iron C in

mm

ol/L

time in hours

0.07

0.06

0.05

0.04

0.03

0.02

0.01

0.00 0 5 10 15 20 25 30

27

S(t)

time in hours

10

9

8

7

6

5

4

3

2

1

0

0 5 10 15 20 25 30

1 2( ) exp( )S t k k t k k t= − ⋅ + ⋅ − ⋅[ ] [ ] ( )0.15obs

d PCE k PCE S tdt

= − ⋅ ⋅ ⋅

[ ] [ ] ( )0.30obsd PCE k PCE S t

dt= − ⋅ ⋅ ⋅

[ ] [ ] ( )0.40obsd PCE k PCE S t

dt= − ⋅ ⋅ ⋅

[ ] [ ] ( )0.60obsd PCE k PCE S t

dt= − ⋅ ⋅ ⋅

[ ] [ ] ( )0.80obsd PCE k PCE S t

dt= − ⋅ ⋅ ⋅

[ ] [ ] ( )obsd PCE k PCE S t

dt= − ⋅ ⋅

Determining Complex Reactions Kinetics of Batch Results at Various GGG Dosages Using EasyFit

Regression Software and a Suitable Complex Model

Dependence of PCE Degradation on Various GGG Dosage at Different Conditions

y = 0.0019x R² = 0.9261

y = 0.0025x R² = 0.926

y = 0.0008x R² = 0.9865

y = 2E-05x R² = -1.147

0

0.05

0.1

0.15

0.2

0.25

0.3

0 20 40 60 80 100 120

Kob

s in

1/h

our

GGG iron weight in mg/L 1min/h (GGG PB3) Continous rotation (GGG PB3)1min/h (GGG PB3 Rusting with Water) 1min/h (GGG PB3 600ºC)Linear (1min/h (GGG PB3)) Linear (Continous rotation (GGG PB3))Linear (1min/h (GGG PB3 Rusting with Water)) Linear (1min/h (GGG PB3 600ºC))

28

Field Application Quality Assurance QA

• Batch experiments should be performed in parallel to the “preferred” column experiment employing 3 – 4 different amounts of the same ZVI or NZVI brand and production charge checked in the column (“preferred” = actually used for dimensioning the PRB in the field).

• k(obs) determined in the column experiment (after 20 – 30 pore volumes, because of potential initial adsorption effects to be encountered) must be assigned to a specific amount / portion of ZVI which is required in the batch experiment to provide / show approximately the same value.

Protocol to check a ZVI production batch prior to its actual application in the field / to PRB

to avoid that a less reactive batch is applied rather than tested before in column experiments!

Protocol for checking the actual reactivity

of a ZVI production batch in an „accelerated“ semi-empirical procedure

• If the batch experiment is repeated later again using the latest production batch of ZVI or NZVI to be loaded actually into a field scale PRB or to be injected into an aquifer, resp., showing approximately the same value of k(obs), there should be no concern to actually apply / use this batch in the field!

• If k(obs) were significantly lower, i.e., in the order of

100 % or more, one should be cautious regarding applying this production batch in the field! Further investigations had to be taken into account.

Put a crater in the middle of each sample with your finger. Put water on each sample, in the crater, and

look to make sure that each sample immediately absorbs water. If it does not, the entire bag is rejected.

In this example, every sample absorbed water. This iron with the water in it is disposed in the trash, as it is no longer useable.

Additional measures

• cubic foot weight (140-160 lb./ft.3 for the particular brand “ETI CC-1004” suitable for applications in PRBs),

• water absorbency, free of oil and grease,

• screen specifications,

• iron content at 85 % minimum, and

• customers packaging requirements.

Therefore, regarding Connelly ZVI, the finished product must meet

ACKNOWLEDGEMENTS • German Federal Ministry for Education and Research (BMBF) for

funding,

• Dr. Karl-Peter Knobel (scientific officer of the RUBIN program), for providing valuable advice over numerous years,

• Eisenwerk Würth GmbH, Bad Friedrichshall, Germany,

• Gotthart-Maier GmbH (Mr. Maier), Rheinfelden, Germany,

• Mittal Steel GmbH, Hamburg, Germany

• Mull-und-Partner Ing. Ges. mbH, Hannover, Germany

Special thanks to:

Connelly-GPM Inc. (Mr. Stephen M. Klein), Chicago, IL, U.S.A.

Thank you very much for your attention!

The 12 Apostles, Great Ocean Road, Port Campbell NP, Victoria, Australia

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