The Landfill Directive & its implications for Remediation. Jan Gronow Science Manager - Waste & Remediation

Transcription

1 The Landfill Directive & its implications for Remediation Jan Gronow Science Manager - Waste & Remediation

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

3 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

4 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.

5 The requirements that most affect remediation the classification of LFs and the end of the codisposal 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.

6 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 codisposed 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

7 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%)

8 New categories for soil were established by the revised EWC soil (including excavated soil from contaminated sites), stones & dredging spoil * soil and stones containing dangerous substances soils and stones other than those mentioned in * dredging spoil containing dangerous substances dredging spoil other than those mentioned in

9 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 nonhaz; the product must comply with the WAC for the most appropriate class of landfill.

10 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

11 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.

12 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.

13 A Scenario for mobile contaminants Waste POC1 POC2 GWF B Concentration at points of compliance GWL C POC1 C POC2 GWQ Time Time C Percolation test data Concentration (mg/l) L/S (l/kg) Time(y) Cumulative leached amt (mg/kg) Wash-out L/S (l/kg) Time(y)

14 A Scenario for retarded contaminants Waste POC1 POC2 GWL GWF B Concentration at targets C POC1 GWQ Time C Percolation test data Concentration (mg/l) L/S (l/kg) Time(y) 10 Cumulative leached amount (mg/kg) L/S (l/kg) Time(y)

15 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

16 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.

17 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

18 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

19 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

20 CEN TC 292 Model

21 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.

22 Regularly Generated Wastes derived 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

23 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.

24 Monolithic Wastes Generally non-granular, deliberately produced waste forms Monolithic WACs produced to provide the same degree of environmental protection as the granular ones

25 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.

26 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

27 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

28 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.

29 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.