DEVELOPMENTS IN THE CHARACTERISATION OF CONSTRUCTION MATERIALS AND WASTE MATERIALS FOR ENVIRONMENTAL IMPACT ASSESSMENT PURPOSES

H.A. van der SLOOT*, A. van ZOMEREN*, J.C.L. MEEUSSEN*, ECN, Environmental Impact Assessment GroupPetten, The Netherlands

Workshop on Environmental and Health Aspects of Coal Ash Utilization, Tel Aviv, Israel November 23, 2005

With special emphasis on beneficial use of coal fly ash

- Too many leaching tests addressing the same question

- Too many ways of data representation

- Too limited relation of test conditions with the actual problem(TCLP used far outside its scope of development, unsuitable for evaluation of construction materials)

- Too limited use and relevance of the vast amount of leaching test data generated annually in the industry and research (missing parameters)

- Key information relevant to the outcome and possible interpretation of a leaching test often not reported (pH, EC, Eh, DOC)

MAIN CONCERNS IN RELATION TO LEACHING TEST USE AND DEVELOPMENT

STRONG NEED FOR HARMONISATION OF LEACHING TEST METHODS AND DATA EVALUATION!

A robust and scientifically sound, while practical, framework for characterisation of environmental behaviour of soils, sludges, sediments, wastes and constructions materials in a range of applications and exposure scenarios is in development in EU and US

The framework is a tiered approach, allowing the user to select the level of testing and evaluation required based on the degree of conservatism needed, prior information available, and balancing costs of testing against benefits from more detailed information

FRAMEWORK

Kosson, van der Sloot, Sanchez and Garrabrants, 2002,Environ. Engr. Sci., 19, 159-203.

ROLE OF CHARACTERISATION LEACHING TESTS IN ENVIRONMENTAL JUDGEMENT

Judgement of the application of materials

Quality control of products Product improvement

Limit valuesRelation lab-practice (Scenarios)

Modelling

Efficient measurementsPrecision measurement data

Characterisation leaching tests(identification of mechanisms

and processes)

Assessibility of data: data base/expert system LeachXS

Product modificationMeasurement for verification

Development of criteria for regulation

Regulation

Compliance leaching tests

X

SCENARIO APPROACH IN JUDGING IMPACT

APPLICABLE TO:

CONSTRUCTION MATERIALS,

SOIL, SLUDGE,

SEDIMENT,

WASTE,

MINING WASTE,

PRESERVED WOOD,

AIRDUST

etc

Lab, lysimeter, field data collection, data management, data formatting, storage and retrieval

Problem definition and test selection

pH, L/S & time dependence - redox, DOC, EC, ANC

Release with time Granular MonolithicPercolation related Surface area

Source term description

Impact evaluation subsoil and groundwater

Judgement and decision makingQC; Regulatory aspects

Treatment, Disposal, Utilization, Remediation end-points, long-term stewardship requirements

Expe

rt s

yste

m /

data

base

Dat

a in

tegr

atio

n b

etw

een

fie

lds

and

test

s, m

odel

ing

and

veri

fica

tion

ag

ain

st f

ield

dat

a

Physical , chemical, biological properties

Management Scenario Description – configuration, design specifications, infiltration, climate

EN 12920

STANDARDS ARE NEEDED FOR EXISTING OR UPCOMING EU REGULATIONS

• Sewage Sludge Directive 86/278/EEC• Soil Monitoring Directive (Proposal 2004)• Biowaste Directive (Proposal 2004) • Landfill Directive 1999/31/EC• Mining waste Directive• Construction Products Directive (ER3)• Water Framework Directive• Groundwater Directive• …………..

BASIC CHARACTERISATION TESTS

TANK LEACH TEST

(MONOLITH) and

COMPACTED GRANULAR

LEACH TEST.

PERCOLATION LEACHING TEST

(PrEN 14405)

Controllingfactors

Modelling leaching

Validationverification

Evaluation

Conclusions

ScenarioDescription

Materialcharacterization

GRANULAR MATERIALS

MONOLITHIC MATERIALS

or

pH DEPENDENCE TEST : BATCH MODE ANCprEn 14429 or

COMPUTER CONTROLLED

or

pH DEPENDENCE TEST : BATCH MODE ANCprEn 14429 or

COMPUTER CONTROLLED

CEN/TC 292 EN 12920

Chemical speciation aspects Time dependent aspects of release

0.1

1

10

100

1000

10000

0 2 4 6 8 10 12pH

Lea

ched

qua

ntity

(mg/

kg) MATRIX

MINERALOGY CHANGES DUE TO REMINERALIZATION

TOTAL

POTENTIALLY LEACHABLE

ACTUAL LEACHING (Metal)

SOLUTION CHEMISTRY

WASTE SLUDGE

CONTAMINATED SOIL

NATURAL SOIL

COMPOST

SEDIMENT

WOOD

STABILIZED WASTE AND CONCRETE

RELEVANT pH DOMAINS FOR DIFFERENT FIELDS

COMPARABILITY OF TESTS AND TEST CONDITIONS RELATED TO DIFFERENT EXPOSURE CONDITIONS

Relevant pH domains for assessing different questions in relation to different types of impact

0.01

0.1

1

10

100

1000

1 3 5 7 9 11 13pH

Lea

ched

at L

/S=1

0 (m

g/kg

)

PrEn 14429Duplicate test PrENSCENaNO3EDTAHacCaCl2CENSCE2Total composition

Cd

INGESTIONINHALATION

CEMENT STABILIZATION OF CONTAMINATED SOIL

NATURAL SOIL

ACIDIC ENVIRONMENTS

SOIL LIMING

Heavily Sewage Sludge

Amended Soil

Total

LeachXS Structure

pH dependent emission of Zn

0.001

0.01

0.1

1

10

100

2 4 6 8 10 12 14

pH

Emis

sion

(mg/

kg)

Cumulative release of Zn

0.001

0.01

0.1

1

10

100

0.1 1 10

L/S (l/kg)C

umul

ativ

e re

leas

e (m

g/kg

)

Cluster of QC data

Comparison of Coal fly ash data with regulatory criteria – DUTCH BuildingMaterials Decree (BMD)

For granular materials info obtained from pH dependenceand percolation is complentary. In this case, Zn proves not to be critical under any normal exposure condition.

BMD Criteria

Pilot Nauerna (12,000 m3), NL

Lysimeters (1.5 m3), NL

Percolation test equipment (0.0005 m3)

COMPARISON BETWEEN LAB,

LYSIMETER AND FIELD DATA

INDIVIDUAL WASTES VERSUS INTEGRAL WASTE MIX

Individual wastes test data

Ba0 .01

0 .1

1

10

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

Cu0.001

0 .01

0 .1

1

10

100

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)DOC

1

10

100

1000

10000

100000

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

Ni0 .001

0.01

0 .1

1

10

100

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

Mg0 .1

1

10

100

1000

10000

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

Zn0 .0 1

0 .1

1

1 0

1 0 0

1 0 0 0

1 0 0 0 0

1 3 5 7 9 1 1 1 3

pH

Leac

hed

(mg/

kg)

INDIVIDUAL WASTES VERSUS INTEGRAL WASTE MIX

Integral waste mix

Integral waste mix enriched with organic rich waste

Individual wastes

A waste mixture behaves quite systematic

Ba0 .01

0 .1

1

10

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

Cu0 .001

0 .01

0 .1

1

10

100

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

N i0 .001

0 .01

0 .1

1

10

100

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

Mg0 .10

1 .00

10 .00

100 .00

1000 .00

10000 .00

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

DOC1

10

100

1000

10000

100000

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

Zn0 .01

0 .1

1

10

100

1000

10000

1 3 5 7 9 11 13

pH

Leac

hed

(mg/

kg)

EU LFD Non-

hazardous

0.01

0.1

1

10

100

1000

1 6 11pH

[Pb]

(mg/

kg)

CARSHREDDER DREDGE SPOILDRILLING MUD SOIL CLEANUPCONT. SOIL CARSHREDDERLYS+DRILLING LYS+C&DWLYS+ORG. MAT LYS+SHREDDERLYS+STRAALGRIT LYS+SEWAGELYSIMETER LYSIMETERSOIL CLEANUP PAINT RESIDUESEWAGE SLUDGE Directive

0.0000001

0.000001

0.00001

0.0001

0.001

0.01

0.1

1

10

100

1000

0.000001 0.0001 0.01 1 100

L/S (l/kg)

Cum

. rel

ease

, [Pb

] (m

g/kg

)

NAU Pilot NAU PilotLYSIMETER LYSIMETERLYSIMETER2 LYSIMETER-ORGLYSIMETER-ORG COL-LYS-ORGCOLUMN-LYS Directive

EU LFD-Non-hazardous

Slope 1 (solubility control)

EU LFD Inert

EU LFD Inert

Consistent behaviour between different scales of testing. Predominantly inorganic waste concept meets inert landfill criteria for Pb (and others, except Cl and SO4)

CHARACTERISATION OF LANDFILLED WASTE BEHAVIOUR AND COMPARISON WITH EU LFD CRITERIA

0.01

0.1

1

10

4 6 8 10 12 14

pH

[PA

K-E

PA]

(mg/

kg)

LYSIMETER

LYSIMETER-ORG

0.0000001

0.000001

0.00001

0.0001

0.001

0.01

0.1

1

10

0.0001 0.001 0.01 0.1

L/S (l/kg)

Cum

. rel

ease

, [P

AK-

EPA

] (m

g/kg

)

1 10

LYSIMETERLYS-ENCAPLYS-ENCAPLYS-ORGLYS-ORGCOLUMN

Increased organic matter level leads to increased PAH releaseBatch test leads to higher release than a percolation test.PAH behaviour very consistent at different scales of testing.Largely same approach in testing and judgement possible as for inorganics.

LEACHING OF PAH FROM THE NAUERNA WASTE MIX

RELEASE PREDICTION USING SIMPLE AND MORE SOPHISTICATED TOOLS - PREFERENTIAL FLOW

Solubility control and wash-out offer possibilities to predict release with reasonable certainty

Mobile non-interacting constituents (e.g Cl) can provide insight in role of preferential flow aspects at different scales of testing.

0.0001

0.001

0.01

0.1

1

10

100

1000

10000

100000

0.00001 0.001 0.1 10L/S (l/kg)

Cum

ulat

ive

rele

ase

(mg/

kg)

SO4

K=0.10; C0=750 mg/l

0.0001

0.001

0.01

0.1

1

10

100

1000

10000

0.00001 0.001 0.1 10L/S (l/kg)

Cum

ulat

ive

rele

ase

(mg/

kg)

Cl

K=0.9; C0=4000 mg/l

K=0.9; C0=4000 mg/l; delay factor: 10

Column (up-flow)

Lysimeters

Pilot Nauerna

CALCULATED CUMULATIVE WASH-OUT IN % RELATIVE TO THE COLUMN

EXPERIMENT AT LAB SCALE (Upflow, same L/S condition)

Experiment Na % K % Cl %

Nauerna Pilot 46 36 28

LYSIMETER 23 16 22

LYS + Shredder and Sludge 33 23 21

Rather consistent wash-out behaviour at the lysimeter and field scale. After correction for the lab test (85 % leached in upflow) preferential flow leaves 70 - 80 % of the material unaffected.

1. pH dependence leaching test on samples for chemical speciation purposes (monolithic materials after size reduction)

2. measurement of release from granular material (column) or monolithic specimen (type of tank test)

3. speciation modelling using LeachXS a database-coupled version of the modelling environment ORCHESTRA to identify relevant mineral phases (SI-indices)

4. refined prediction of leaching behaviour in a pH dependence test based on the selected minerals (from SI units) and other relevant phases (e.g. Fe, clay, DOC, POM)

5. this resulting speciation is used as input for the chemical reaction/transport modelling to describe the release from a column or monolithic specimen

6. model the field scenario with external factors (e.g. carbonation, oxidation) and realistic estimates of infiltration.

APPROACH TO GEOCHEMICAL/ TRANSPORT MODELLING

INPUT PARAMETERS FOR GEOCHEMICAL MODELLING OF COAL FLY ASH

Coal fly ash (anonymous source)

Solved fraction DOC 0 DOC concentrationsSum of pH and pe 15.00 pH kg/l Polynomial coeficientsL/S 10.0000 4.90 0.0E+00 C0 0.0E+00Clay (Al oxide) 0.000E+00 kg/kg 6.20 0.0E+00 C1 0.0E+00Fe oxide (HFO) 2.000E-03 kg/kg 8.10 0.0E+00 C2 0.0E+00Organic matter - solid (SHA) 0.000E+00 kg/kg 8.90 0.0E+00 C3 0.0E+00Organic matter - liquid (DHA) 0.000E+00 kg/l 10.30 0.0E+00 C4 0.0E+00

11.70 0.0E+00 C5 0.0E+00Reactant concentrations

Reactant mg/kgAg+ n.a. F- 6.50 NO3- n.a.Al+3 1770.00 Fe+3 0.13 PO4-3 20.00

H3AsO4 0.59 Hg+2 n.a. Pb+2 5.00H3BO3 84.13 I- n.a. SO4-2 1003.73Ba+2 10.77 K+ 12.00 Sb[OH]6- 0.20Br- n.a. Li+ n.a. SeO4-2 0.90

Ca+2 20730.00 Mg+2 1201.00 H4SiO4 2071.00Cd+2 n.a. Mn+2 7.47 Sr+2 n.a.

Cl- 62.60 MoO4-2 3.06 Th+4 n.a.H2CO3 9070.00 Na+ 317.30 UO2+ n.a.CrO4-2 23.06 NH4+ n.a. VO2+ n.a.Cu+2 n.a. Ni+2 n.a. Zn+2 1.67

Selected MineralsBoehmite BaCaSO4[50%BFerrihydrite Manganite Otavite Pb[OH]2[C]Diaspore CaMoO4[c] CSH_ECN Hilgenstockite Calcite Wairakitemonosulfate_ECFluorite Brucite Strontianite Pb2V2O7Ba[SCr]O4[77% Portlandite Magnesite Willemite PbMoO4[c]

Input specification

PREDICTION OF pH DEPENDENT LEACHING BEHAVIOUR OF COAL FLY ASH

One set of conditions for all parameters simultaneously: Element availabilities, selected minerals, Fe-oxide and clay sorption, POM and DOC interaction.

0.000000001

0.00000001

0.0000001

0.000001

0.00001

0.0001

0.001

0.01

0 2 4 6 8 10 12 14

Con

cent

ratio

n (m

ol/l)

Al

0.0001

0.001

0.01

0.1

0 2 4 6 8 10 12 14 16

Ca

1E-11

1E-10

1E-09

1E-08

0.0000001

0.000001

0 2 4 6 8 10 12 14

Con

cent

ratio

n (m

ol/l)

Fe

1E-12

1E-11

1E-10

1E-09

1E-08

1E-07

1E-06

0.00001

0.0001

0 2 4 6 8 10 12 14 16

Mn

1E-10

1E-09

1E-08

1E-07

0.000001

0.00001

0 2 4 6 8 10 12 14

Con

cent

ratio

n (m

ol/l)

Pb

0.00000001

0.0000001

0.000001

0.00001

0 2 4 6 8 10 12 14

Zn

0.0000001

0.000001

0.00001

0.0001

0.001

0.01

0 2 4 6 8 10 12 14

Mg

0.00001

0.0001

0.001

0.01

0 2 4 6 8 10 12 14 16

Si

0.000001

0.00001

0.0001

0.001

0.01

0 2 4 6 8 10 12 14 16

SO4

0.00000001

0.0000001

0.000001

0.00001

0 2 4 6 8 10 12 14 16

Ba

0.0000001

0.000001

0.00001

0 2 4 6 8 10 12 14

Mo

0.00001

0.0001

0 2 4 6 8 10 12 14

K

0.0000001

0.000001

0.00001

0.0001

0 2 4 6 8 10 12 14

pH

Con

cent

ratio

n (m

ol/l)

Cr0.000000001

0.00000001

0.0000001

0.000001

0 2 4 6 8 10 12 14

pH

As

0.00000001

0.0000001

0.000001

0.00001

0 2 4 6 8 10 12 14

pH

Se

0.0000001

0.000001

0.00001

0.0001

0.001

0 2 4 6 8 10 12 14

pH

B

Prediction and partitioning in the pH dependent leaching test for Cr and Mo in Coal Fly Ash

Relevance of mineral formation, interaction with Fe phases for retention of oxyanions in coal fly ash (ettringite type phases)

MoO4-2 fractionation in the solid phase

0%

20%

40%

60%

80%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

of to

tal

conc

entra

tion

(%)

POM-bound FeOxide CaMoO4[c] PbMoO4[c] Mo-Ettr.

CrO4-2 fractionation in the solid phase

0%

20%

40%

60%

80%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Frac

tion

of to

tal

conc

entra

tion

(%)

POM-bound FeOxide Ba[SCr]O4[77%SO4] Cr-Ettr.

[MoO4-2] as function of pH

1.E-07

1.E-06

1.E-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Con

cent

ratio

n (m

ol/l)

Mo

Partitioning liquid and solid phase, [MoO4-2]

1.E-07

1.E-06

1.E-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Free DOC-bound POM-bound FeOxideCaMoO4[c] PbMoO4[c] Mo-Ettr.

[CrO4-2] as function of pH

1.E-07

1.E-06

1.E-05

1.E-04

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Cr

Con

cent

ratio

n (m

ol/l)

Partitioning liquid and solid phase, [CrO4-2]

1.E-07

1.E-06

1.E-05

1.E-04

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pHFree DOC-bound POM-bound

FeOxide Ba[SCr]O4[77%SO4] Cr-Ettr.

[Mg+2] as function of pH

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1.000E-02

1.000E-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [Mg+2]

Mg

[Sr+2] as function of pH

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [Sr+2]

Sr

[Al+3] as function of pH

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1.000E-02

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [A l+3]

Al

[Ca+2] as function of pH

1.000E-04

1.000E-03

1.000E-02

1.000E-01

1.000E+00

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [Ca+2]

Ca

[Cu+2] as function of pH

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [Cu+2]

Cu

[Mn+2] as function of pH

1.000E-12

1.000E-11

1.000E-10

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [Mn+2]

Mn

[SeO4-2] as function of pH

1.000E-08

1.000E-07

1.000E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [SeO4-2]

Se

[PO4-3] as function of pH

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [PO4-3]

PO4

[H4SiO4] as function of pH

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1.000E-02

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Conc

entr

atio

n (m

ol/l)

Series1 [H4SiO4]

Si

[SO4-2] as function of pH

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1.000E-02

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Conc

entr

atio

n (m

ol/l)

Series1 [SO4-2]

SO4 as S

[Ni+2] as function of pH

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Conc

entr

atio

n (m

ol/l)

Series1 [Ni+2]

Ni

[Pb+2] as function of pH

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Conc

entr

atio

n (m

ol/l)

Series1 [Pb+2]

Pb

[Fe+3] as function of pH

1.000E-12

1.000E-11

1.000E-10

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [Fe+3]

Fe

[Ba+2] as function of pH

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Conc

entr

atio

n (m

ol/l)

Series1 [Ba+2]

Ba

[Zn+2] as function of pH

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Conc

entr

atio

n (m

ol/l)

Series1 [Zn+2]

Zn

[CrO4-2] as function of pH

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [CrO4-2]

Cr

[H3BO3] as function of pH

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1.000E-04

1.000E-03

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [H3BO3]

B

[MoO4-2] as function of pH

1.000E-10

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [MoO4-2]

Mo

[Sb[OH]6-] as function of pH

1.000E-08

1.000E-07

1.000E-06

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pHC

once

ntra

tion

(mol

/l)

Series1 [Sb[OH]6-]

Sb

[VO2+] as function of pH

1.000E-09

1.000E-08

1.000E-07

1.000E-06

1.000E-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Series1 [VO2+]

V

Geochemical modelling of Cement Mortar

All elements simultaneously, including all relevant minerals, Fe oxide sorption and solid solutions such as ettringite substition

100

1000

10000

100000

0.1 1 10 100Time (days)

[Na]

(µg/

l)

Prediction of Na concentration in the tank test NEN 7345

Cumulative release of Na

100

1000

10000

100000

0.1 1 10 100

time (days)

Cum

ulat

ive

rele

ase

(mg/

m²)

slope=0.5 Orchestra CEM I (H5) data

Slope 0.5

8

8.5

9

9.5

10

10.5

11

11.5

12

12.5

0.1 1 10 100Time (days)

pHCumulative emission of K

1000

10000

100000

0.1 1 10 100

time (days)

Cum

. em

issi

on (m

g/m

²)

slope=0.5 Orchestra CEM I (H5) data

pH

Na K

Na

PREDICTION OF TANK TEST RESULTS BASED ON PH STAT DATA FOR A CEM I MORTAR

pH not yet good for this specimen inearly cycles.

Transport for “inert”species apparently well described

Liquid renewal cycles in the test

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

1.00E-01 1.00E+00 1.00E+01 1.00E+02

Time (days)

[Ca]

(µg/

l)

Cumulative release of Ca

100

1000

10000

100000

0.1 1 10 100

time (days)

Cum

ulat

ive

rele

ase

(mg/

m²)

slope=0.5 Orchestra Series2

Partitioning liquid and solid phase, [Ca+2]

1.000E-04

1.000E-03

1.000E-02

1.000E-01

1.000E+00

1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

Con

cent

ratio

n (m

ol/l)

Free DOC-bound POM-bound FeOxide Clay Minerals

[Ca+2] as function of pH

1.000E-04

1.000E-03

1.000E-02

1.000E-01

1.000E+00

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00

pH

Con

cent

ratio

n (m

ol/l)

H5 (P,1,1) [Ca+2]

Ca

CaCa

Ca

Transport for a solubility controlled major element like Ca quite well described.

PREDICTION OF TANK TEST RESULTS BASED ON PH STAT DATA FOR A CEM I MORTAR

soil: unsaturated

saturated zone (groundwater transport)

Material (e.g., aggegate)

possible liner (e.g., road)

source term

pathpoint of compliance (object)

Depending on the modeled groundwater quality at the POC (which might be chosen anywhere), limits to the release of the construction products might be adjusted such that the product eventually complies with the groundwater limit value at the POC.

Time

Con

cent

ratio

n. a

t PO

C

Groundwater limit value

Time

Con

cent

ratio

n. a

t PO

C

Groundwater limit value

APPROACH FOR DEVELOPING REGULATORY CRITERIA – Forward modelling and backwards adjustment of acceptance values based on quality criteria at POC

60 days

Modeling release from construction material by percolation

Construction material

Soil

Point of compliance

Interface reactions

pH Al

Na SO4

Mg

CaCl

H2CO3Pb

Fe

Ferri-hydrite

Alsolid

Calcite Portlandite

iterations CuH2CO3solid

Mg

Brucite

Si

Tenorite CrEttringite

Cusolid

Cusolid

Pbsolid

Construction Products Directive - Essential Requirement No3 on Health & Environment –

Release of Dangerous substancesMandate accepted by Standing Committee Construction on October 26 2004

Mandate has been issued to CEN

Work plan for BT176 is now being drafted

Start of the horizontal standardisation work on: SamplingIndoor airImpact to soil and groundwater(ECRICEM/ECO Serve Cluster 1 input)

WT-Products Non WT-Products

Assessment of construction productsin view of

CPD/ER No. 3

Conformity Evaluationacc. to prescribed Conformity System

FT-ProductsWFT-Products

Non WT-Products

ConventionallyApproved Materials

CE -markingWT = Without testing

WFT = Without further testing

FT= Further testing

CONFORMITY ASSESSMENT IN THE CPD Main aim: avoid unnecessarytesting and focus on the key issues

LIFE CYCLE ISSUES IN SOIL & GROUND AND SURFACE WATER IMPACT

• Service life: different exposure scenarios• Constructions in water• Constructions on land• Drinking water pipes/basins

• Recycling stage (bound): same as service life• Reuse stage (unbound): different exposure scenarios

• Road base/embankment• Structural fill (dikes, soundbarriers)

• “End of life”: Landfill scenarios• Inert landfill• Non-hazardous waste landfill

Characterisation testing provides information on the abovementioned life-cycle stages

Primary Raw Materials

Alternative raw materials

Stage 1 Raw material supplies

Stage 2:Manufacture of construction materials and elements

Recycling of construction debris

Stage 4:Service Life

Stage 3:Construction Process Stage 5:

Demolition

Release into the environment

Energy

Dust, noise emissions

Energy

“End of Life”

Environmental impact (dusting)

Supply of information on technical and environmental

quality: Database/

expert system

Characterisation (ITT) of monolith/ granular leaching behaviour

Monolith/granular QC and compliance leaching test

Characterisation of granular leaching

Granular compliance test

TEST USE IN RELATION TO THE LIFE CYCLE OF CONSTRUCTION PRODUCTS

RELEVANT PAPERSHOW TO JUDGE RELEASE OF DANGEROUS SUBSTANCES FROM CONSTRUCTION PRODUCTS TO SOIL AND GROUNDWATER

CPD Topic 1 - Soil and groundwater impact

CPD Topic 2 - Hierarchy in testing: Characterisation, initial type testing, further testing and selection of tests in specific stages of material judgement

CPD Topic 3 – Proposal for reference to ER 3 aspects in product standards and in CE marking

J. J. Dijkstra (ECN) H. A. van der Sloot (ECN) G. Spanka (VDZ) G. Thielen(VDZ) ECN-C--05-045

DEVELOPMENT OF HORIZONTALLY STANDARDIZED LEACHING TESTS FOR CONSTRUCTION MATERIALS:A MATERIAL BASED OR RELEASE BASED APPROACH?

Identical leaching mechanisms for different materials

H.A. van der Sloot and J.J. Dijkstra ECN-C--04-060

Presentations at Workshop by EAWAG in Meiringen May 2005

CONCLUSIONSCharacterisation leaching tests, such as developed in CEN/TC 292/WG 6, provide the source term for modelling long term release from coal fly ash, wastes, contaminated sites and construction materials.

A limited number of well selected leaching tests can provide thecrucial answers needed to assess impact and evaluate sustainability.

Comparison between laboratory scale leaching tests, lysimeter experiments and full scale verification is needed to be able to develop sustainable utilisation and disposal concepts. First steps are very promising.

Understanding the role of mineral formation, sorption onto clay,Fe-oxides and “residual” organic matter (non-degradable) in relation to mobilisation in DOC-bound form is of importance to minimize porewater concentrations in the material matrix.

CONCLUSIONS Reduction of DOC levels in leachate by proper acceptance criteria will lead to significantly decreasing concentrations of inorganic and organic contaminants in the leachate from any type of material. This does not imply banning organic matter as residual, non-degradable organic matter is quite acceptable (provides binding).

Transport modeling in its simplest form already provides goodprediction potential for long term release for a range of constituents.

The leaching of organic contaminants and the judgement of impact can be addressed in a very similar manner as for inorganiccontaminants.

An expert system coupled with a database of characterisation and field data will provide a very useful tool for constrction and wastetreatment industry, consultants and regulators

CONCLUSIONSWith the modelling capabilities now presented sequential chemical extraction (SCE) is outdated

The present model capabilities replace the widely used Kd concept by a more detailed description of the actual chemistry. The main aspect being the mutual interaction between constituents which is ignored in a Kd approach.

Multi element and multi parameter modelling allows identification of missing or inadequate stability data for minerals or sorption parameters.

CONCLUSIONSThe methodology and release controlling processes illustrated here for coal fly ash and cement with coal fly ash are equally relevant for contaminated soil, amended soil, mining waste and alternative materials used in construction.

The emphasis on specific release controlling factors may be stronger for one material than for another, but all aspects may play a role as different parameters are affected by different release controls (e.g. Cu is very sensitive to even very small amounts of DOC).

Understanding leaching behaviour should be exploited more extensively as it holds the key to treat materials in such a way that long term solutions are achieved rather than reaching temporary gains.

FUTUREChallenges: proper description of pH and DOC generation from various materials for prediction of inorganic and organic contaminant release from construction materials, soil and disposed waste.

Mining of old data sources containing valuable leaching data currently inaccessible because of poor data format, non-electronic data forms.

Prediction of release behaviour of mixture of materials

Developing generic scenario descriptions based on fundamental leaching information for easy application by end-users in construction applications, contaminated soil site evaluation, treatment of waste and development of sustainable landfill concepts.

ACKNOWLEDGEMENT

In this work information has been presented from Sustainable Landfill project that is an initiative of the Dutch

Cooperation of Waste Processing Industries, Afvalzorg, Essent, and VBM.

Part of the work presented relates to activities in ECO Serve (EU project) as well as work for the Dutch Ministry of

Environment

INFORMATION ON LEACHING AVAILABLE AT:

LEACHING BACKGROUNDwww.leaching.net (Wascon 2003 workshop)

CONSTRUCTION PRODUCTS DIRECTIVEwww.cenorm.be/cenorm/workarea/sectorfora/construction+sector+network/conference.asp

LEACHING IN PROJECT HORIZONTALwww.ecn.nl/horizontal

GRACOS EU project on contaminated soil and sedimentwww.uni-tuebingen.de/gracos

Additional Background Slides

CEN/TC 292 -ENV 12920

Controllingfactors

Modelling leaching

Validationverification

Evaluation

Conclusions

ScenarioDescription

Materialcharacterization

pH DEPENDENCE TEST TO ASSESS SENSITIVITY TO CHANGES IN pH, EH

AND TEMPERATURE

(PrEn14429 Batch mode test)

ADVANTAGES OF pH DEPENDENCE TEST

- Identification of sensitivity of leaching to small pH changes

- Provides information on pH conditions imposed by external influences

- Basis for comparison of international leaching tests- Basis for geochemical speciation modelling- Provides acid neutralization capacity information- Mutual comparison of widely different materials to assess similarities in leaching behaviour

- Recognition of factors controlling release- For non-interacting species possible to assess sub-sampling error

Applicable to almost any material

CEN/TC 292 -ENV 12920

Controllingfactors

Modelling leaching

Validationverification

Evaluation

Conclusions

ScenarioDescription

Materialcharacterization

Liquid to solid ratio (L/S) related to a time scale by infiltration rate, density and height of application.

TEST CONDITIONS:Pre-equilibration after saturation for more than 48 hrs

Up-flow

L/S range 0.1 - 10 (100 - 1000 yrs)

Test data in mg/l or mg/kg cumulative

PERCOLATION TEST TO ASSESS LONG TERM RELEASE FOR GRANULAR MATERIALS PrEn14405

ADVANTAGES OF PERCOLATION TEST

- Identification of solubility control versus wash out- Indication of pore water concentrations relevant to field leachate from low L/S data

- Local equilibrium established quite rapidly - Basis for geochemical speciation modelling- Allows comparison with lysimeter and field data provided L/S value can be obtained from such measurements

- Projection towards long term behaviour possibleSolubility controlled releaseWash-out of non-interacting species

Applicable to many materials. Limited or not applicable to clayey soils and sediments (low permeability).

CEN/TC 292 -ENV 12920

Controllingfactors

Modelling leaching

Validationverification

Evaluation

Conclusions

ScenarioDescription

Materialcharacterization

TEST CONDITIONS:First step: pre-equilibration for 48 hrs at liquid to volume ratio: 5 Second step: leaching at low L/V ratio (1) for 24 hrsThen contact times: 2, 4, 8,16, 32 and 64 daysLeachant: demineralised water (own pH)

Expression of results in mg/m2 (cumulative)against time

TANK LEACH TEST OR COMPACTED GRANULAR LEACH TEST (CGLT) FOR MONOLITHIC MATERIALS (modified)

CGLT = Compacted Granular Leach Test

EXPERIMENTAL SET-UP

ADVANTAGES OF TANK LEACHING TEST OR COMPACTED GRANULAR LEACH TEST

- Relevant for materials with monolithic character (durable materials) or materials behaving as monolith (low permeability soil and sediments)

- Identification of solubility control versus dynamic leaching possible

- Isolation of surface wash-off effects- Quantification of intrinsic release parameters - Basis for reactive/transport modelling- Projection towards long term behaviour possible

Applicable to sediments, clayey soils, stabilised materials and construction materials produced