Effects of biochar on remediation of heavy metal contaminated soil or marginal agricultural land

Jasmin Karer

Outline

NAWARO-SAN project – introduction

Study sites - overview Heavy metal immobilisation

Plant yields Conclusions

NAWARO-SAN project financed project, running from September 2012 to December 2014

Project partners:

Renewable primary products: yield potentials through soil remediation of

industrial wasteland or marginal agricultural land

Which soil additives are able to effectively immobilise heavy metals?

Mario Wagner Miscanthus GmbH

NAWARO-SAN project Project structure, sub projects:

• Screening experiment 1: greenhouse study, soil: humus-depleted or contaminated, crop: ryegrass (Lolium multiflorum), duration: 3 months

• Screening experiment 2: greenhouse study, soil: humus-depleted or

contaminated, crop: maize and Miscanthus, resp. willow (Salix), duration: 18 months

• Screening project 3: field study, soil: humus-depleted or

contaminated, crop: maize and Miscanthus, resp. willow, duration: 18 months

4

Screening project 1:

Historically contaminated soil:

industrial heritage site with mining and smelting activities since about 600 years.

Lead and zinc ores were processed for centuries

Photograph: Klaus Platzer

Arnoldstein

Soil characteristics Arnoldstein: heavy metal contamination pH

(CaCl2) EC

(µS cm-1) P-CAL

(mg kg-1) K-CAL

(mg kg-1) 5.97 68.8 4.5 49.0

Corg (%) CEC (mmolc kg-1) clay (%) silt (%) sand (%)

4.0 151 18 25 57 Total heavy metal contents (mg kg-1) in the top soil (0 – 20 cm):

Cd Pb Zn Cu Ni

36 2805 4496 221 56 0.5 100 150 60 60

1 trigger values for contaminant contents in the top soil (0 – 20 cm) for agricultural and horticultural use, according to ÖNORM S 2088-2

Total heavy metal content:

Trigger values1 :

BC pH (CaCl2) EC

(mS cm-1) P-CAL

(mg kg-1) S-BC 8.05 31.7 1222 P-BC 7.91 28.8 816 M-BC 7.78 56.8 853

Biochar characteristics

8

Abbreviations of Treatments

L Lime (0.5 %) S-BC Standard BC (fiber sludge + husk, 1.5 %) with compost 50/50 with N enrichment P-BC Poplar BC (1.5 %) with compost 50/50 with N enrichment M-BC Miscanthus BC (1.5 %) with compost 50/50 with N enrichtment GSFe Gravel sludge with siderite bearing material (3%)

Concentration of NH4NO3-extractable Cd

control L S-BC P-BC M-BC GSFe

mg

kg-1

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0

a

b

c c

d

e

Concentration of NH4NO3-extractable Pb

control L S-BC P-BC M-BC GSFe

mg

kg-1

0,0

0,3

0,6

0,9

1,2

1,5

1,8

2,1

2,4

a

b

ccd

d

e

Results

Concentration of NH4NO3-extractable Cd, Pb and Zn in the soil

9

trigger values for soils (derived for feed quality according to Prüeß, 1994) and Deutsches Bundesbodenschutzgesetz

Concentration of NH4NO3-extractable Zn

control L S-BC P-BC M-BC GSFem

g kg

-10

5

10

15

20

25

30

35

40

a

bb

c

dd

control L S-BC P-BC M-BC GSFe

mg

kg-1

0,0

0,1

0,2

0,3

0,4

0,5

aa

b b

c

d

Concentration of NH4NO3-extractable Cu

control L S-BC P-BC M-BC GSFe

pH (C

aCl 2

)

0

2

4

6

8

a bc cd d

pH

control L S-BC P-BC M-BC GSFe

mg

kg-1

0,00

0,01

0,02

0,03

0,04

0,05

0,06

a

bbc

c

dd

Concentration of NH4NO3-extractable Ni

Results

Concentration of NH4NO3-extractable Cu and Ni in the soil

10

L Lime (0.5 %) S-BC Standard BC (fiber sludge + husk, 1.5 %) with compost 50/50 with N enrichment P-BC Poplar BC (1.5 %) with compost 50/50 with N enrichment M-BC Miscanthus BC (1.5 %) with compost 50/50 with N enrichtment GSFe Gravel sludge with siderite bearing material (3%)

Concentration of NH4NO3-extractable Zn

control L S-BC P-BC M-BC GSFe

mg

kg-1

0

5

10

15

20

25

30

35

40

a

bb

c

dd

Concentration of NH4NO3-extractable Zn

control P-BC GSFe P-BC + GSFe0

10

20

100

200

300

400

0 - 10 cm 10 - 20 cm

b

a

a

a

a

aa

a

mg

kg-1

Zn immobilisation in greenhouse and field experiment

11

Greenhouse Field experiment

L Lime (0.5 %) S-BC Standard BC (fiber sludge + husk, 1.5 %) with compost 50/50 with N enrichment P-BC Poplar BC (1.5 %) with compost 50/50 with N enrichment M-BC Miscanthus BC (1.5 %) with compost 50/50 with N GSFe Gravel sludge with siderite bearing material (3%)

P-BC Poplar BC (1.5 %) with compost 50/50 with N enrichment GSFe Gravel sludge with siderite bearing material (3%) P-BC + GSFe Poplar BC (1.5 %) with gravel sludge (0.75 %) and siderite bearing material (0.75 %) with N enrichment

control L S-BC P-BC M-BC GSFe

mg

kg-1

0

2

4

6

8

10

12

14

16

a

b

b

bb b

Cd concentration in Lolium multiflorum

control L S-BC P-BC M-BC GSFe

mg

kg-1

0

5

10

15

20

25

30

35

a

bbcbc

bcc

Pb concentration in Lolium multiflorum

Results screening project 1

Cd, Pb and Zn in Lolium multiflorum

12

Critical values (Cd, Pb) (according to EU Directive 2002/32/EG) Toxicity value (Zn) (Sauerbeck, 1982)

control L S-BC P-BC M-BC GSFe

mg

kg-1

0

200

400

600

800

1000

a a a

bbb

Zn concentration in Lolium multiflorum

Ni concentration in Lolium multiflorum

control L S-BC P-BC M-BC GSFe0

1

2

3

4

5

6

a

ababc

bcc

c

mg

kg-1

control L S-BC P-BC M-BC GSFe

mg

kg-1

0

10

20

30

40

a

a

bbcc c

Cu concentration in Lolium multiflorum

Results screening project 1

Cu and Ni in Lolium multiflorum

13

Dry mass of Lolium multiflorum

control L S-BC P-BC M-BC GSFe

g pe

r pot

0

1

2

3

4

5

6

aab

c

abc

bc

ab

Results: Lolium multiflorum yield

Dry mass

14

• Heavy metal immobilisation and/or growth stimulation – need of different biochars

L Lime (0.5 %) S-BC Standard BC (fiber sludge + husk, 1.5 %) with compost 50/50 with N enrichment P-BC Poplar BC (1.5 %) with compost 50/50 with N enrichment M-BC Miscanthus BC (1.5 %) with compost 50/50 with N enrichtment GSFe Gravel sludge with siderite bearing material (3%)

Results: Screening project 2 and 3

15

Miscanthus yield – greenhouse study Total maize yield –

field experiment

Mineral fertiliser 1 % P-

BC + N +

compost

3 % P-BC + N

+ compost

1.5 % GS 1.5. % Fe

1.5 % P-BC + N +

compost + 0.75 % GS +

0.75 % Fe

Control + mineral fertiliser

1 % S-BC

0.5 % S-BC + N

1 % S-BC + N

Ct and Nt in Miscanthus

control P-BC GSFe P-BC + GSFe0

1

240

45

% Nt % Ct

a

a

a a a

aa a

%

Ct and Nt in different soil depths

control P-BC GSFe P-BC + GSFe

0,2

0,4

3,0

4,0

6,0

7,0

0,0

5,0

% Nt 0 - 10 cm % Ct 0 - 10 cm % Nt 10 - 20 cm % Ct 10 - 20 cm

ab

b

a ab

a

b

aa

a a a a

a a a a

%

Results: Screening project 3, field experiment Arnoldstein

16

P-BC Poplar BC (1.5 %) with compost 50/50 with N enrichment GSFe Gravel sludge with siderite bearing material (3%) P-BC + GSFe Poplar BC (1.5 %) with gravel sludge (0.75 %) and siderite bearing material (0.75 %) with N enrichment

Conclusions Biochar supports immobilisation of certain heavy metals in contaminated

soils Variability of heavy metal immobilisation after biochar treatment depending

on the element

Wood-based biochar infers more positive effects

One biochar doesn‘t fit all - different soil contamination problems require different additives

Long term studies will help to distinguish between pH- and sorption effects

of biochar

17

Thank you!

Jasmin Karer jasmin.karer@gmx.at

NAWARO-SAN project: Franz Zehetner, Gerald Dunst, Mario Wagner, Markus Puschenreiter, Wolfgang Friesl-Hanl, and Gerhard Soja

KLI.EN-funds and FFG (New Energies 2020,

project nr. 825438)