A bird's-eye view on contaminant leaching research at ECN · (1) Development and standardization of...
Transcript of A bird's-eye view on contaminant leaching research at ECN · (1) Development and standardization of...
A bird's-eye view on
contaminant leaching research at ECN
J.J. Dijkstra (ECN)
A. van Zomeren (ECN)
September 2014
ECN-L--14-048
www.ecn.nl
A bird’s-eye view on contaminant leaching research at ECN
Joris Dijkstra, Andre van Zomeren E&EE – Environmental Assessment
Rapperswil 10-11 September 2014
Outline
• About ECN • What is contaminant leaching? • Our approach and activities: highlights and examples
Important processes, findings Laboratory test development and standardization Model development to predict leaching in practice Applications of our research: tools and know-how for the industry and government
• Who are our clients • What makes the ECN approach unique compared to other institutes?
ECN R&D fields
Policy Studies
Energy Engineering
Environment Energy Efficiency
Wind Energy
Solar Energy
Biomass
Process & Energy Industry
~600 employees
Position
fundamental research
industrial development
• independent • connecting partners
Industrial partners Universities
applied research
Work field: contaminant emissions to soil and groundwater
Similar questions for different scenarios
SOURCE TERM
TRANSPORT
IMPACT
Road base
L/S
[con
c]
Point of compliance
SOURCE TERM
TRANSPORT
IMPACT
SOURCE TERM
TRANSPORT
IMPACTIMPACT
Road baseRoad baseRoad base
L/S
[con
c]
L/S
[con
c]
Point of compliancePoint of compliance
Examples of domain and regulations around leaching
• NL: Soil Quality Decree (“construction products” including recycled materials), dredged sediments (under development)
• EU: Landfill Directive (waste that cannot be re-used) • EU: Construction Products Directive / Regulation: (under development) • United States, wastes: leaching limit values • Many more examples
“Horizontal” development leaching tests • Testing can be seen as the first step in “source term” characterization • >1000 different products and scenarios, > 1000 tests? Inefficient! • Construction products, soil, waste: similar leaching mechanisms • Use that knowledge, group by mechanisms • Horizontal: -> “level playing field”, consistent regulation, cost-efficient
brick
Roof tiles
Waste materials in construction, e.g., bottom ash
Contaminated soil, sludge
brick
Roof tiles
Waste materials in construction, e.g., bottom ash
Contaminated soil, sludge
Importance of release mechanisms
Time
[conc] ?
diffusion
percolation
Release by percolation (granular) Water passes through material Equilibrium High concentration
Mass Transfer Release (monoliths) Water is around material Diffusion from material surface Lower concentration
“Tank test” CEN/TS-2, TS15863 and EPA 1315
1 Sample
n analytical samples
A1
L1
A2 An
L2 Ln
Δt1 Δtn
or Monolith
Compacted Granular
n Leaching Intervals
Δt2
Diffusion
Release fresh product during “intended use” Regulated test method in NL (NEN7375) Standardized in TC351 (“TS2”), TC 292, US-EPA
pH dependency of release
2 4 6 8 10 12pH
Soluble salts (Cl, Br)
2 4 6 8 10 12
pH2 4 6 8 10 12
pH
Anions (SO42-
AsO43-, MoO4
2-, CrO4
2-)
Cations (Ni2+, Cu2+, Zn2+)
Log release (mg/kg)
• Release is a function of physical and chemical processes. • pH is one of the dominant chemical influencing factors
• pH varies in different environments; • pH of products changes during “intended use” of products (ageing); • pH will be different during recycling and end-of-life
pH dependence test
ISO TS 21268-4, CEN TS14497, CEN TS14497, US-EPA 1313
ECN philosophy on contaminated materials
• Not the total content is relevant but potential and actual leaching!
• Leaching depends strongly on pH
• Predictions based on generic processes: chemical speciation (rather than empirical / ad hoc approaches)
0.01
0.1
1
10
100
1000
10000
0 2 4 6 8 10 12 14 pH
Con
tam
inan
t con
cent
ratio
n (m
g/kg
)
Total concentration
Potentially leachable (“availability”)
Actual leaching
Me 2+
-(OH) x Me
Enhanced leaching by DOC
Me -DOC
ECN philosophy on contaminated materials
0.01
0.1
1
10
100
1000
10000
0 2 4 6 8 10 12 14 pH
Con
tam
inan
t con
cent
ratio
n (m
g/kg
)
Total concentration
New Concrete (pH 13)
“Aged” concrete (pH 8)
Fresh waste incineration ash (pH 12)
Landfill pH 4-6
Natural soils (pH 5-7)
(1) Development and standardization of leaching tests
• Development of generic appliccable leaching tests
• Standardization of these tests
• Development of automated systems for the market and licensing (together with Rohasys)
Standardized leaching tests with ECN involvement
Test/Matrix
Soil, sediments, compost and sludge Waste Mining waste Construction products
pH dependence test ISO/TS21268-4 CEN/TS14429 CEN/TS14429 CEN/TS14429CEN/TS14497 CEN/TS14497
EPA 1313 * EPA 1313 EPA 1313 EPA 1313Percolation test ISO/TS21268-3 CEN/TS14405 CEN/TS14405 CEN/TC351/TS-3
EPA 1314 * EPA 1314 EPA 1314 EPA 1314Monolith test CEN/TS15683 CEN/TC351/TS-2
EPA 1315 * EPA 1315 EPA 1315 EPA 1315Compacted granular test NEN7347 CEN/TC351/TS-2
EPA 1315 EPA 1315 EPA 1315 EPA 1315Redox capacity NEN 7348 NEN 7348Acid rock drainage PrEN15875
Reactive surfacesISO/CD12782 parts 1-5
* EPA drafts in preparation for inclusion in SW846
(3) Model development
Experiment
database withstability constants
Geochemical speciationmodelling
computerprogram
assumptions
Cu2+??
?
CuOH+
Cu+
Cu2+
H+ (pH)Cu2+
Experiment
database withstability constants
Geochemical speciationmodelling
computerprogram
assumptions
Cu2+??
?
CuOH+
Cu+
Cu2+
H+ (pH)Cu2+
Modified after M. Gfeller & R. Schulin, ETH, Zürich
1
(ORCHESTRA)2
• Leaching (source term) and
reactive transport in soil/groundwater are governed by the same processes
• based on fundamental thermodynamic parameters
• Sorption models with generic parameters 3,4
• Implementation in Orchestra2
• no fitting!
1 NIST/MINTEQ 4.0; 2 Meeussen (2003); 3 Milne et al. (2003); 4 Dzombak & Morel (1990)
Dijkstra et al., Environmental Science and Technology (2004), 38, 4390-4395; & (2009), 43, 6196-6201
Cd
1.E-10
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
0 2 4 6 8 10 12
pH
conc
entr
atio
n (m
ol/L
)
Pb
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
0 2 4 6 8 10 12
pH
data soil Idata soil IVdata soil VIImodel soil Imodel soil IVmodel soil VIItotal soil Itotal soil IVtotal soil VII
Zn
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
0 2 4 6 8 10 12
pH
Cu
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
0 2 4 6 8 10 12
pH
Ni
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
0 2 4 6 8 10 12
pH
conc
entr
atio
n (m
ol/L
) Ni(OH)2(s)
Pb(OH)2(s)
Zn(OH)2(s)
Guideline for modelling of leaching processes → New Work Item ISO/NP 19648 accepted
Experiment
database withstability constants
Geochemical speciationmodelling
computerprogram
assumptions
Cu2+??
?
CuOH+
Cu+
Cu2+
H+ (pH)Cu2+
Experiment
database withstability constants
Geochemical speciationmodelling
computerprogram
assumptions
Cu2+??
?
CuOH+
Cu+
Cu2+
H+ (pH)Cu2+
Modified after M. Gfeller & R. Schulin, ETH, Zürich
(ORCHESTRA)
“Available” concentrations: → Leaching at low pH (≈0.4) (ISO TS 21268-4)
Dissolved organic matter: → Humic and fulvic acids*
ISO DIS 12782-5
Reactive surfaces in the solid phase: → SOM (humic/fulvic acids)*
ISO DIS 12782-4
→ Fe/Al (hydr)oxide minerals
ISO DIS 12782-1 (Feam) ISO DIS 12782-2 (Fecryst) ISO DIS 12782-3 (Alam)
(3) Model parameterization
(3) Model development
Accessible model tools and applications
LeachXS: database expert system (ECN, Vanderbilt University, DHI) • LeachXS Lite (free license, developed mainly for US-EPA) • LeachXS Pro (License fee)
• Databases with > 10000 results of leaching tests, > 1000 materials • Tools for interpretation, regulations, statistics, plotting, reporting • Tools for modelling
(4) Applications (recent and ongoing)
• Development criteria for sustainable landfills, dredged sediments • Quality improvement steel slag • Quality improvement bottom ash • Dossiers on environmental quality of construction products • Measurement and modelling for several clients, quality improvement, ... • ....
(4) Applications (recent and ongoing)
• ECN calculated emission criteria for construction products in Soil Quality Decree; together with RIVM (national public health institute)
• First time a fundamental model approach was followed; • Approach is now being used for criteria for sustainable landfills, dredged
sediments, ...
Citation analysis (peer-reviewed) ECN leaching research*
*Search terms: leaching – waste – ash – slag (ISI Web of Science)
Results found: 3,816 Sum of the Times Cited: 33,688 Average Citations per Item: 8.83
Results found: 32 Sum of the Times Cited: 1,107 Average Citations per Item: 34.6
No.1 most cited institutes
2 papers in top-10 most cited
12 papers in top-100
All peer-reviewed papers
All peer-reviewed papers
Thank you for your attention!
Example: enhanced metal leaching in natural and waste materials
….MSWI bottom ash : copper leaching often > limit value (no recycling possible)
Waste incineration & use of ashes in construction is beneficial use
What causes enhanced metal leaching?
• Several ECN publications in high impact journals (van Zomeren, Comans et al.)
• Patent on quality improvement
using a technique based on this process
• Development and standardization of methods: ISO DIS 12782-4/5
fulvic acids (16.9%)
humic acids (0.3%)
hydrophilic acids (82.7%)
Types of models Simple empirical (fitting): “Kd” • Advantage: simple • Disadvantange: too simple, large uncertainty, no generic validity
Scientific (based on insights in processes, no fitting): • Processes on molecular scale are more general valid. Makes assessments for
specific soils possible. • Since years ECN has been co-developing these models and testing against
measurements
Empirical: lineair partitioning (Kd)
Cd 1.E-10
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
0 2 4 6 8 10 12 pH
conc
entr
atio
n (m
ol/L
)
Kd Kd = [Me]soil/[Me]solution Aanname Kd = constant! [Me]solution = [Me]soil/Kd
Main sorption processes in soils
(2) Identification of fundamental leaching processes: chemical form (“speciation”)
CuOH+
Cu2+Cu2+ Cu
Cu+
–
pH
temperature ionic strengthcomposition
(“available” fractions) time
solid particles(reactive mineral andorganic surfaces)
organische ligands(humic- and fulvic acids)
transport in soiland groundwateruptake by plants and(micro)organisms
CuOH+
Cu2+Cu2+ Cu
Cu+
–
pH
temperature ionic strengthcomposition
(“available” fractions) time
solid particles(reactive mineral andorganic surfaces)
organische ligands(humic- and fulvic acids)
transport in soiland groundwateruptake by plants and(micro)organisms
0,0E+00
1,0E-02
2,0E-02
3,0E-02
4,0E-02
5,0E-02
6,0E-02
0 200 400 600 800 1000Tijd (Jaar)
Time (years)
Aver
age
GW
con
c. (m
g/l)
Risk limit value
Stationary (Fig. 1A), lower sat.
Dynamic (Fig. 1B)
Preferential flow 20% mobile (Fig. 2A)
Preferential flow mixed layer (Fig. 3)
Copper
Model sensitivity – hydrology
Bronte
0 m
-1.0 m
-2.0 m
Gemengde bovenlaag en onderla
Bronterm
0 m
-1.0 m
-2.0 m
Gemiddeldeconcentratiegrondwater
Gemiddeldeconcentratiebodem
Stationaire waterstroming
Bronter
0 m
-1.0 m
-2.0 m
Niet-stationaire waterstroming
Bronterm
0 m
-1.0 m
-2.0 m
Gemiddeldeconcentratiegrondwater
Gemiddeldeconcentratiebodem
Nietbeschikbaar
Preferente stroming
Non-available
Source term Source term
Source term Source term
1B. Non-stationary water flow 1A.Stationary water flow
2A. Preferential flow (20%) 3. Preferential flow (mixed layer)
Average Conc. soil
Average Conc. GW
Average Conc. soil
Average Conc. GW
Original
Mixed layer
Different transport velocity in the soil
“Old” experiment at school: The ink of a marker consists of a cocktail of color agents. Some are bound more strongly to the coffe- paper (the “soil”) than others. This becomes visible when water flows through the paper due to capillary forces.
Time
Dijkstra et al., Environmental Science and Technology 43, 6196–6201 (2009)
IAGC Hitchon award 2009 for best scientific paper in Applied Geochemistry 2006-2009
on the pH-dependence test Dijkstra, J.J., Van der Sloot, H.A., Comans, R.N.J. (2006), Applied Geochemistry, 21, 335-351
ECN-L--14-048 Fout! Geen tekst met de opgegeven stijl in het document. 3
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