The Landfill Directive & its implications for Remediation

Jan GronowScience Manager - Waste & Remediation

Contents▪ Requirements & implications of LFD▪ Classification of LF sites▪ Treatment & sorting▪ WAC development▪ The testing hierarchy ▪ Sampling▪ Characterisation▪ Compliance testing▪ Monolithic wastes

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

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.

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.

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

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%)

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.

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.

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

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.

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.

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

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

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

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.

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

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

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

CEN TC 292 Model

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.

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

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.

Monolithic Wastes

Generally non-granular, deliberately produced waste forms

Monolithic WACs produced to provide the same degree of environmental

protection as the granular ones

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.

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

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

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.

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.