Screening Matrix for Initial Evaluation
of Methods for Treatment of Sediments
Project acronym:
Title of project:
Project No:
SMOCS
Sustainable Management of Contaminated Sediments
Baltic Sea Region Programme Project No #39
Report status:
Date:
Final
2011-05-24
Author/Organisation:
Lennart Larsson, SGI
SMOCS WP5
SGI
2011-05-24
SCREENING MATRIX FOR INITIAL EVALUATION OF METHODS FOR
TREATMENT OF SEDIMENT
TABLE OF CONTENTS
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
Initial screening of potential site-specific methods
Introduction
Example how to use the Screening Matrix
Screening Matrix for initial evaluation of methods for treatment of sediment
Definitions of factors and abbreviations in the Matrix
Notes for “Treatable contaminants” in Table 2
Explanation on groups of contaminants in the Matrix
Conceptual idea on relationship between final concentrations, method and energy
References
1
INITIAL SCREENING OF POTENTIAL SITE-SPECIFIC METHODS
1.1 Introduction
Screening of potential methods for treatment of sediments facilitates final selection of a sitespecific method. Screening usually consists of several evaluation steps. In this report one
such step, designed as a matrix, is presented (chapter 1.3). It should primarily be used as a
first rough selection tool, if needed together with other suitable tools early in the selection
process. Hence, the matrix covers only a limited part of the initial evaluation/selection process that is needed in order to get a foundation of suitable methods that will be evaluated in
the final site-specific selection process.
This initial screening may be viewed as a part of, or complementary to, a multi-criteria decision analysis (MCDA) needed in order to find the most suitable site-specific method (may
include risk assessment/risk based selection, life cycle analysis, socio-economic objectives,
energy efficiency, stake-holder opinions etc.). Tools for MCDA are taken forward within WP3
in this SMOCS project. Additionally, a complementary user friendly decision support tool,
which takes into account broad aspects/consequences of using, or not using, different measures for remediation of contaminated areas, can be found in Andersson-Sköld et. al. (2011).
Figure 1 shows a simplified example on where the given screening Matrix may fit (second
box from the left) as a part within a suggested pathway of activities. As indicated above, the
flow path to final full scale operation may include different types of screening/evaluation
steps along the way (in, or in between, the given boxes).
Site characterisation
Initial
screening
of methods
Laboratory-/
pilot tests
Final selection of
method
Design/Construction/Implementation
Operation/
Maintenance
Figure 1. Example on flow path/pathway of activities coupled to treatment of sediments. In
order to simplify, the pathway does not include finalising the treatment.
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1.2 Example how to use the Screening Matrix
Selection of treatment method/-s is an iterative process with the goal to finally find the most
suitable site-specific method or combination of methods. As indicated above, the given Matrix (chapter 1.3) may be used iterative but shall be seen as one of several tools that may be
needed in order to select the final method. It is appropriate that the initial usage of the Matrix
results in several method candidates and these need to be further investigated on their site
specific suitably. The purpose of the Matrix is herby to support during the first selection step
of remedial alternatives. The matrix can be used according to following example.
1/ As default no restrictions are set using the remediation methods given in the Matrix. If any
site-specific restriction a priori excludes a method then delete all coupled to that method it in
the Matrix.
2/ Define the type/group of contaminants (see groups in the Matrix, with additionally support
in Table 3) that shall be remediated in the sediment. In this example it is assumed heavy
metals and PAH.
3/ Do a first site-specific setting for metals and PAH, exemplified in Table 1.
Compare Table 1 with the Matrix. The result in this example is that no method satisfies all the
demands. Herby, one or several demands need to be lowered, primarily such that has limited
site-specific negative influence if lowered.
Revised demands may correspond additionally to that
1/ it is ok with either capital intensive (significant cost in equipment etc.) or operation intensive (in both cases still with low total cost) but not both, and
2/ it is ok with no significant reduction of contaminant mass, still with the demand on reduction of environmental impact.
Comparing the new revised settings/demands with the Matrix reveals that there is only one
method, Stabilisation/Solidification ex situ, that satisfies all the demands. If in this stage the
demands had ended up with still no suitable method, a second revised demand list had to be
done and compared with the Matrix.
Further, ending up in only one method gives, in this stage, too limited supply, or number of
methods, to proceed further with. At least three methods should be finally selected from this
initial screening in order to have relevant number of methods to evaluate towards other types
of evaluation schemes or programs (see Introduction above). Herby, further originally demand or demands need to be lowered, also here with primary focus only to change those
demands that at this stage can be easiest accepted for the final outcome.
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Table 1. Example on first setting for screening with the Matrix in chapter 1.3. Left column (Factor / Parameter) is a copy of part of the first row in
the Matrix (turned 90 degrees), chapter 1.3. The two columns to the right contains the first settings or demands for a method to be used for treatment of the selected sediment. The settings is then compared with the content in the Matrix.
3
A = Average
B = Bad
C = Capital
ET = Not applicable
F = Full Scale
G = Good
L = Liquid
M = Medium
N = No
O = Operation & Maintenance
P = Pilot Scale
S = Solid
T = Both
V = Gas
Y = Yes
Z = Other (see Table 2)
A: UPTAKE TECHNOLOGY
Dry excavation
Dry Excavation
Mechanical: Grab dredgers
Mechanical: Backhoe dredgers
Mechanical: Bucket (ladder) dredgers
Hydraulic: Cutter suction dredger
Hydraulic: Trailing suction hopper dredgers
Freeze dredging
Environmental dredging
Dredging
4
CODE
Tin-organic compounds (TBT)
Inorganic (Metals)
Fuels (e.g. diesel, gasoline, fuel oils)
Halogenated semi-volatile hydrocarbons (e.g. PCB)
Non-halogenated semi-volatile hydrocarbons (e.g. PAH)
Halogenated volatile hydrocarbons (e.g. PCE, TCA)
Non-halogenated volatile hydrocarbons (e.g. BTEX)
Cost (Good=low)
Treatment -\ Remediation time (Good=short)
Technical reliability / Maintenance
Method availability in Europe
O-intensive or C-intensive
SMOCS WP5
Rest products produced
Method needs treatment train
Development status
Treated masses can be used in structure application
Containment (Yes means both Y and N valid)
Reduction of contaminant mass
Reduction of environmental impact
Applicable in 1: Sand; 2: Silt; 3: Clay; 4: Gyttja
Technical applicability for sediment
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2011-05-24
1.3 Screening Matrix for initial evaluation of methods for treatment of sediment
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2011-05-24
B: IN SITU TREATMENT (Z, see Table 2)
In Situ Physical/Chemical Treatment
Stabilisation/Solidification
Chemical oxidation (ISCO)
Electrokinetic separation
Capping
Soil flushing
G
B
A
G
A
1-4
1-2
2-4
1-4
1-2
Y
Y
Y
Y
Y
Monitored natural attenuation
Enhanced attenuation
Phytoremediation
B
A
B
1-2
1-2
1-4
Y
Y
Y
Electrical resistance heating
Steam injection and extraction
Conductive heating
Radio frequency heating
In situ vitrification
B
A
B
B
A
2-4
1-2
2-4
2-4
2-4
Y
Y
Y
Y
Y
Stabilisation/Solidification
Gas-phase chemical reduction
Liquefied gas solvent extraction
Separation
Dehalogenation
G
G
G
G
G
1-4
1-4
1-4
1-2
1-2
Y
Y
Y
Y
Y
Bioslurry
Biopiles
Landfarming
Composting
Phytoremediation
G
G
G
G
A
1-2
1-2
1-2
1-2
1-4
Y
Y
Y
Y
Y
Thermal desorption
Incineration
Pyrolysis
G
G
G
1-3
1-3
1-3
Y
Y
Y
N
Y
Y
N
Y
Y
N
N
Y
N
Y
Y
Y
N
Y
F
F
F
F
F
N
N
Y
N
N
(S)
N
L
(S)
L
C
O
O
O
O
G
M
B
M
G
M
M
M
M
M
G
G
M
G
M
M
M
B
G
B
B
A
A
A
G
B
A
A
A
G
G
B
A
G
A
G
A
A
G
A
B
B
B
A
A
G
Z
G
G
G
B
Z
Z
A
G
O
O
N
G
G
M
M
M
B
B
M
B
G
G
G
G
G
A
A
G
B
B
A
A
B
B
B
Z
G
A
B
Z
A
Z
Z
Z
T
T
T
T
T
M
M
B
B
B
G
G
M
M
M
G
M
G
M
B
M
B
B
B
B
G
G
A
G
G
G
G
A
G
G
G
A
A
G
G
G
A
A
G
G
G
A
A
G
G
B
B
B
B
G
B
B
A
A
G
C
T
T
O
T
G
B
M
G
M
G
M
M
G
B
G
G
M
G
M
G
B
M
M
B
B
B
A
A
B
B
G
A
A
G
G
B
G
A
B
G
G
G
A
G
B
B
A
B
B
G
B
B
A
B
B
B
B
A
B
T
N
N
N
N
G
G
G
G
M
M
G
G
G
B
M
M
M
M
B
B
G
G
G
G
A
G
G
A
A
G
A
A
A
B
G
A
A
A
A
A
B
B
Z
B
G
G
G
G
A
Z
B
B
B
A
B
B
Z
B
Z
T
T
T
G
G
G
M
M
B
G
G
G
M
B
B
G
G
A
G
G
A
G
G
G
G
G
G
G
G
A
B
D
B
B
G
Z
In Situ Biological Treatment
Y
Y
Y
N
N
N
Y
Y
Y
F
F
F
N
N
N
N
N
(L),S
In Situ Thermal Treatment
Y
Y
Y
Y
Y
N
N
N
N
Y
Y
Y
Y
Y
N
F
F
F
(F)
F
Y
N
N
N
N
L.V
L,V
L,V
L,V
S,V
C: EX SITU TREATMENT
Ex Situ Physical/Chemical Treatment
N
Y
Y
Y
Y
Y
N
N
N
N
Y
Y
Y
Y
Y
F
F
F
F
F
N
Y
N
Y
Y
(S)
V
L
S
V
Ex Situ Biological Treatment
Y
Y
Y
Y
Y
N
N
N
N
N
Y
Y
Y
Y
Y
F
F
F
F
F
Y
N
N
N
N
S,L,V
V
N
N
S,(L)
Ex Situ Thermal Treatment
Y
Y
Y
N
N
N
Y
Z
Z
F
F
F
Z
N
N
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L,S
S,L,V
S,L,V
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D. DEWATERING TECHNOLOGY
Lagooning
Lagooning
Mechanical Dewatering (MDW)
Mechanical Dewatering (MDW)
Geotubes
Geotubes
Thermal Dewatering
Thermal Dewatering (Drying)
Thermal Dewatering (Freezing)
Combined Technologies
Thermally Assisted Dewatering
Electro-Dewatering (EDW)
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1.4 Definitions of factors and abbreviations in the Matrix
Table 2. Some factors and definitions used in the Matrix.
FACTOR
Development status
Treatment train
Rest product produced (need to be taken care of/treated)
O-intensive or K-intensive
(O: Operation and maintenance; C: Capital)
DEFINITION
F: Method has been used in full scale during remedia- P: Method only been tested in laboratory, pilot or in
tion.
Y: Method usually used in combination with other
treatment methods
S: Solid phase
L: Liquid phase
O: Extensive/intensive
C: Capital intensive
operation, maintenance
full scale for limited technical optimisation.
N: Method can be used without the necessity of
coupling with other methods (parallel or serie).
V: Gas phase
N: No/none
T: Both O and C
N: Neither O nor C
Z = Other
IN SITU TREATMENT
Treatable contaminants have been divided in seven groups
In general for the In Situ methods: The evaluation for Technical applicability, Availability, Reliability, Cost and
Contaminants are afflicted with significant uncertainties, except for the methods Stabilisation/Solidification
(s/s) and Capping. With this exception, all the methods have sparsely, if all, been used for treatment of sediment In Situ. All usage of the evaluations for these in situ methods (except s/s and Capping) shall therefore
be done with this reservation.
Effectiveness depends on contaminant, application and design /See chapter “1.5 Notes for Table 2”
and evaluation is based on judged treatability in literature
Method availability in Europe
Technical reliability / Maintenance
In relation to the other listed remediation methods
Treatment -\ Remediation time
Based on the time it takes to treat the less recalcitrant group of
substances/compounds. Time corresponds to an assignment to
remediate approx. 30 000 ton wet sediment.
B = Bad
M = Medium
G = Good
Less than two suppliers
Low reliability
Extensive maintenance
More than 3 years In Situ
2 - 4 suppliers
Average reliability
Average maintenance
1 – 3 years
More than 4 suppliers
High reliability
Low maintenance
Less than 1 year
More than 1 year Ex Situ
0.5 – 1 year
Less than 0.5 year
More than €300/ton
€150/ton – €300/ton
Less than €150/ton
No or low remediation effect
in pilot-, or full-scale
Limited effectiveness has been
shown in pilot-, or full-scale
Method shown to be effective in
pilot-, or full-scale
Cost
Cost does not include transport, set up, demobilisation and pre/post-treatment (if needed) of the sediment before /after the
remediation. NOTE! All listed costs are in most cases based on
estimations! (No offer/request has been directed to any selected
distributor/entrepreneur).
Treatable contaminants have been divided in seven groups
and evaluation is based on judged treatability in literature.
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1.5 Notes for “Treatable contaminants” in Table 2
The information below is coupled to Table 2, specifically the row “Treatable contaminants”
which in turn is coupled to the validation given as abbreviation “Z” for treatable contaminants
in the Matrix.
Chemical oxidation In Situ / Inorganics: Depending on type of oxidant, TOC in sediment (steering
amount of oxidant needed), radius of influence and inorganic, oxidation of some inorganics can
change their characteristics, e.g. solubility, precipitation, toxicity.
Chemical oxidation In Situ / Tin-organic compounds: No information available, however theoretically Tin-organic compounds ought to be easy oxidised based on the knowledge that sun radiation can
break down these molecules.
Electrokinetic separation In Situ / Tin-organic compounds: These compounds may theoretically
be separated provided that pH is high, due to that their solubility increases with increased pH (very low
solubility at neutral pH, very high solubility at very high pH). Low pH may have somewhat similar but
not as strong effect.
Monitored natural attenuation: Average for fuels with short-medium sized molecules, bad for long
sized molecules. No information available for TBT.
Enhanced attenuation: The method is capable of generating low redox which for some heavy metal
e.g. Cr6+ may transform them to less toxic ions i.e. Cr3+). No information available for TBT.
Phytoremediation In Situ: No information available for TBT.
Bioslurry: Method not suitable for inorganics, however biotreatment may change redox which may
change their leachability/sorption, e.g. precipitation.
Landfarming: TBT compounds can be removed provided that the method is perfumed under significant sun radiation. Landfarming in tent or indoors is not suitable for TBT-contaminated soils, provided
no artificial UV-radiation.
Composting: Normally, bulking agents are initially added and if such, in the form of selected bark or
woodchips from special trees, then white rot fungus may be added, with good potential for degrading
chlorophenols (e.g. PCP; defined as halogenated semi-volatile compounds).
Phytoremediation Ex situ: No information available for TBT.
Thermal desorption Ex situ: The method includes both LTTD and HTTD. HTTD is usually coupled to
other techniques e.g. incineration plant, s/s treatment of treated soils etc.
Hot gas decontamination: The method is designed for larger matrices than sand (scraps, structures
etc.) and the status is on the border between pilot scale and established full scale.
Incineration: If the produced ashes have acceptable low leachable contaminants when used as final
product or in product mix, then bottom ash may be used as fillings and fly ash as part of binder mix in
stabilisation/solidification.
Pyrolysis: If the product has acceptable low leachable contaminants when used as final product or in
product mix, then it may be used as fillings. No information available for TBT.
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1.6 Explanation on groups of contaminants in the Matrix
In the left upper part of the Matrix main groups of chemicals/contaminants are displayed. Table 3 gives information on what these groups (left column) of contaminants
may contain. Centre column in the table gives example on sub-groups and right column example on specific chemical within corresponding main group.
Table 3. Examples on substances/compounds that are included in the different contaminant groups in the right part of the Matrix.
Group of chemicals
in Matrix
Non-halogenated
volatile
hydrocarbons (VOC)
Halogenated volatile
hydrocarbons (VOC)
Non-halogenated
semi-volatile
hydrocarbons (SVOC)
Halogenated semivolatile hydrocarbons
(SVOC)
Fuels (e.g. diesel,
gasoline, fuel oils)
Inorganic
Tin-organic
compounds
Example of
subgroups
Example
Light aliphates,
Hexane, Octane (Light alifates), Benzene, ToluMonocyclic hydrocarbons ene, Ethylbenzene, Xylenes (Petrol, fuels/propellants, solvents)
Chlorinated aliphates
Perchloroethylene (PCE), Trichloroethylene (TCE)
Trichloroethane (TCA), Methylchloride (CM) (Chlorinated solvents)
Heavier aliphates,
Dodecane, Pentadecane (Heavier Aliphates in e.g.
Polycyclic aromatic
Diesel, Fuel oil, Greese, Transformer oil), Anthrahydrocarbons,
cene, Bens(a)pyrene, Methyl-Phenanthrene (PolyHeterocyclic aromatic
cyclic aromatic hydrocarbons/PAH and alkylated
hydrocarbons
PAH in e.g. Creosote, Transformer oil, Fuel
oil/Heating oil), Dibenzofuran, Benzotiophene,
Carbazole (Heterocyclic hydrocarbons in Creosote).
Chlorinated polyaromatic Polychlorinated Biphenyls (PCB) (Transformer oil),
hydrocarbons,
Pentachlorophenol (PCP) (Wood impregnating
Chlorinated phenols,
chemicals), Polychlorinated Dioxins/Furans
Halogenated Cyclo(PCDD/F) (In Polychlorinated Phenol-based Wood
alkanes
impregnating chemicals), Hexabromocyclododecane (HBCDD) (flame retardant)
Product specific (fuels)
Commercial product-specific mixtures of all the
group (not chemically
above mentioned non-halogenated subgroups,
based sub-group as the
containing light - medium – heavier aliphatic hyabove)
drocarbons and/or light-medium-heavier aromatic
hydrocarbons
Heavy metals
Copper, Chromium, Arsenic, Cadmium, Lead,
Mercury (Metal work, wood impregnating chemicals)
Tin-organic compounds
Tributyltin (TBT) (Protective paints for boat-/vessel
bottoms)
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1.7 Conceptual idea on relationship between final concentrations, method and
energy
Size of the interval between start and final concentration of selected contaminants
before and after a remediation may have major impact on the final remediation cost.
One of several factors for such impact is consumption of energy. Figure 2 gives a
simplified conceptual idea on relationship between degree of contaminant reduction,
obtained by exemplified methods, and cost via consumption of energy.
Figure 2. Simplified conceptual idea on relationship between potential final
concentrations, obtained by some exemplified methods, initial
concentration (at least, or significant larger than, 1000 ppm) and relative
energy consumption. Energy for dredging not included.
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1.8 References
Andersson-Sköld Y., Helgesson H., Enell A., Suer P., Bergman R., 2011. Matrix decision support tool for evaluation of environmental, social and economic aspects of
land use. SGI Varia 613, Swedish Geotechnical Institute.
http://www.swedgeo.se/upload/publikationer/Varia/pdf/SGI-V613.pdf
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