the landfill directive & its implications for remediation · 2005. 6. 30. · the requirements that...
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The Landfill Directive & its implications for Remediation
Jan GronowScience Manager - Waste & Remediation
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Contents▪ Requirements & implications of LFD▪ Classification of LF sites▪ Treatment & sorting▪ WAC development▪ The testing hierarchy ▪ Sampling▪ Characterisation▪ Compliance testing▪ Monolithic wastes
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Acknowledgements
▪ Remediation in the context of the LFD Steve Gibbs & colleagues at Atkins Design, Environment Engineering
▪ Sampling & Testing:Kathy Lewin, Jane Turrell & Julian Ellis at WRc
▪ WACs David Hall & colleagues at Golder Associates (UK) f
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The Landfill Directive
▪ The Landfill Directive & its associated decision document has a significant impact in those parts of Europe that do not have a waste management infrastructure based on incineration.
▪ Planning for the required changes gives an opportunity to review:▪ the cost; & ▪ the sustainability of the measures put in place.
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The requirements that most affect remediation
▪ the classification of LFs and the end of the co-disposal of haz with non-haz wastes;
▪ prohibition of certain waste types from LF;▪ pre-treatment of wastes before LF; ▪ the general characterisation and testing of waste to
be landfilled ▪ the setting of waste acceptance criteria for the
deposit of waste in inert sites and the landfilling of hazardous waste.
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Waste Acceptance Criteria▪ most waste to be treated prior to Landfillng▪ inert waste sites -limit values define inert waste▪ non-haz sites - demonstrate waste is not haz▪ limit values apply only to SNRHW & wastes co-
disposed with them ▪ they define SNRHW & ∴treatment objectives for haz
waste going to non-haz sites▪ others set by permit
▪ haz waste sites - defined by EWC & HWD▪ limit values set upper limits for the landfilling of Haz
waste
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Hazardous Waste Sites▪ Haz waste defined by new EWC & HWD - not by
WACs
▪ Ban on co-deposit of haz & non-haz wastes,▪ Requirement to treat wastes prior to disposal.▪ Stringent nature of WAC for haz waste sites (TOC
6% or 10% LOI)
▪ even more stringent criteria for the placement of SNRHW (TOC 5%)
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New categories for soil wereestablished by the revised EWC.17 05 soil (including excavated soil from
contaminated sites), stones & dredging spoil
17 05 03* soil and stones containing dangerous substances
17 05 04 soils and stones other than those mentioned in 17 05 03
17 05 05* dredging spoil containing dangerous substances
17 05 06 dredging spoil other than those mentioned in 17 05 05.
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to landfill a contaminated soil
▪ it must have been treated;▪ the resultant product must not be a prohibited
waste;
▪ the product must be characterised ▪ it must be assessed as to whether it is haz or non-
haz;
▪ the product must comply with the WAC for the most appropriate class of landfill.
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What is Treatment?A physical, thermal, chemical, or biological process (including sorting) that changes the characteristics of waste in order to:▪ reduce its quantity;▪ reduce its hazardous nature; ▪ facilitate its handling (in the LF); or ▪ enhance recovery. Dilution via mixing with uncontaminated media to meet WACs is not acceptable; nor is:▪ bagging▪ wetting▪ compaction
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Sorting
▪ This appears to have potential in the short term for remediation of soils.
▪ The segregation of haz soils from non-haz is required & is likely to have economic benefits.
▪ If sorting is to be regarded as a treatment, not all of the resulting fractions can be landfilled - one fraction at least must be diverted from landfill.
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WAC Development
▪ A procedure based on GW modelling to establish a relationship between: ▪ the behaviour of inorganic contaminants released by
leaching from waste in a LF; & ▪ the risk these contaminants pose to GW.
▪ Used back-calculation: ▪ from GW quality criteria at specific compliance points
downstream of the LF;▪ to corresponding limit values for the results of leaching
tests on the waste ▪ assessed sensitivity to assumptions made & to account for
this when limit values were set.
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A Scenario for mobile contaminants
POC1 POC2
GWF
B Concentration at points of compliance
Waste
GWL
C C
Time Time
Percolation test data
1
10
100
1000
10000
0.1 1 10L/S (l/kg)
Con
cent
ratio
n (m
g/l)
Time(y)10 100 1000
100
1000
10000
0.1 1 10L/S (l/kg)Cum
ulat
ive
leac
hed
amt (
mg/
kg)
Wash-out
Time(y)10 100 1000
POC1
GWQPOC2
C
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Scenario for retarded contaminantsA
POC1 POC2
GWF
Waste
GWL
B Concentration at targets
C
Time
Percolation test data
POC1
C
0.001
0.01
0.1
1
10
0.1 1 10L/S (l/kg)
Cum
ulat
ive
leac
hed
amou
nt(m
g/kg
)
Time(y)10 100 1000
0.001
0.01
0.1
1
10
0.1 1 10L/S (l/kg)
Con
cent
ratio
n (m
g/l)
Time(y)10 100 10
GWQ
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Three Tier Hierarchy of Testing
▪ Level 1 - Characterisation- the responsibility of the person sending the
waste to landfill
▪ Level 2 - Compliance Checking- the responsibility of the operator
▪ Level 3 - on-site verification of every load- the responsibility of the operator
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Sampling
▪ There is absolutely no point in doing any testing unless the sample has been chosen correctly
▪ For the sampling of waste, a sampling plan shall be developed according to part 1 of the standard (prEN 14899:2004)
▪ The plan should include everything from the sampling objectives to the toolbox of appropriate methods for the site specific situation.
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Basic Characterisation▪ source & origin of the waste;▪ process producing the waste ▪ appearance; ∗ EWC code; ∗ relevant hazard properties; ▪ whether the waste can be recycled or recovered;▪ waste treatment applied (Reg 10(1)) ∗ composition, other characteristic properties & where relevant,
leaching test values;▪ demonstrate the waste is not prohibited under Reg 9;▪ LF class at which the waste may be accepted;∗ likely behaviour in a LF (& if relevant, leaching behaviour) & any
precautions to be taken at the landfill; ∗ key variables
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Characterisation Testing (1)▪ If hazardous - any testing to demonstrate which
hazard etc. ▪ Composition ▪ there are standard methods for:▪ sample preparation▪ sample digestion▪ analysis of digestate
▪ To inform compliance testing▪ key variables▪ variability
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Characterisation Testing (2)
▪ total availability EA NEN 7371:2004▪ pH dependence prEN 14997:2004 or
prCEN/TS 14429:2003▪ Leaching characteristics▪ upflow percolation prCEN/TS 14405:2003▪ standard leaching ▪ granular BS EN 12457:2002▪monolithic EA NEN 7375:2004
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CEN TC 292 Model
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Compliance Testing▪ When waste has been deemed acceptable for LF it
shall be subject to compliance testing.
▪ Compliance testing is to check that the waste complies with the basic characterisation
▪ The parameters to be tested are determined by the basic characterisation.
▪ The compliance tests used shall be one or more of those used in the basic characterisation.
▪ Compliance testing shall be carried out at least once a year at the frequency determined by the basic characterisation.
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Regularly Generated Wastesderived from a process with well-defined inputs that generates waste with consistent characteristics & constituents within known boundaries▪ requires infrequent characterisation but more stringent
compliance testing a more inconsistent waste produced regularly as a result of variable inputs &/or a variable ‘recipe’ (e.g. merchant treatment plant, aggregate recovery plant or waste transfer plant). ▪ requires frequent characterisation
Both types require compliance testing
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One-off Wastes▪ Compliance testing is required for all wastes
except ‘one-off’ consignments:▪ Q these are characterised immediately before
arriving at site;▪ they are individual wastes that exist & where
all of the waste is available to be sampled for characterisation;
▪ characterisation is representative of the whole consignment which might be several loads delivered over several days.
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Monolithic Wastes
Generally non-granular, deliberately produced waste forms
Monolithic WACs produced to provide the same degree of environmental
protection as the granular ones
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Characterisation of plant output
▪ Wastes entering waste-forming plant must meet TOC or LOI limits
▪ plant should provide appropriate number of monolithic testing samples at start-up & whenever the feed to the plant or the ‘recipe’ changes
▪ >40mm in any direction ▪ Compressive Strength of 1.5 MPa or greater
depending on site conditions.
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Characterisation of wastes for a site risk assessment (1)▪ 8 stage 64 day EA NEN 7375:2004 tank test gives
long term diffusive leaching from the waste product. ▪ Cumulative data should meet full 64 day leaching
limit values for monolithic wastes.▪ If a cementaceous binder is used the waste forms
should cure for 28d, as the test also indicates the longevity of the waste form.
▪ The test is to demonstrate that emissions result from diffusion & not from advection or a solubility controlled mechanism
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Characterisation of wastes for a site risk assessment (2)▪ The following tests on the ground monolith are used
for LF site risk assessments to:▪ quantify the source term; and ▪ to predict changes in leachability should the
monolith be overlain by waste of different pH & buffering capacity.
▪ max availability for leaching (EA NEN 7371:2004); ▪ pH dependent leaching (prCEN/TS 14429:2003); and▪ calculation of ANC/BNC
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Compliance testing at the LF
▪ A shortened version of the standard 64 day tank test (EA NEN 7375:2004).
▪ Cumulative leaching from the first 4 steps of the test is the benchmark for periodic compliance testing.
▪ Samples must be >40mm in any direction.▪ There is no requirement to cure the sample ▪ WAC for monolithic wastes are ¼ of the values given
for Level 1 characterisation.
▪ No need to determine EC at compliance.
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Conclusions
▪ The LFD introduces a raft of measures with considerable implications for the remediation of contaminated soils.
▪ These measures entail: ▪ increased responsibilities for waste holders to
characterise their wastes, ▪ a significant increase in the cost of landfilling ▪ a reduction in the number of landfill sites.
▪ it is time to invest in treatment technologies that reduce reliance on landfilling.
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