Manywells Landfill: determination, management & communication

1. Manywells Landfill:determination, management & communication Ann Barker Lead Officer Contaminated Land

2. Structure of presentation • Part IIA reminder • Location and background • Initial negotiations • Assessment actions • Determination • Part IIA issues post-determination • Resources Interaction with E.A. • Technical challenges • Leachate, temperature and gas • Community confidence and communications • Conclusion and recommendations

3. Part IIA: Reminder • Backstop! • Only to be used where other regimes are not applicable • Requires viable potential or actual significant pollutant linkage • Based on risk assessment • Forensics - the polluter pays – search for appropriate persons

4. Manywells: location

5. 1994: A new waste disposal landfill site is born, formed from a disused sandstone quarry in Cullingworth Photo-montage by local resident

6. Commissioned and operated as a licensed waste disposal site 1994 to 2001 Photo-montage by local resident

7. Site operator, Wastepoint Ltd, went bankrupt in 2001, deserting the site

8. Manywells became an “orphan” site

9. Site overfilled by approx 90,000 cubic metres Uncontained leachate seeping to surface

10. Waste mass towers over surrounding land levels Unstable gradients The first view… Landfill gas migration onto public bridleway and into woods

11. Exposed waste seen from bridle path

12. Background • Operational waste management issues • Odour • Flies • January 2002 • Contact from Minerals & Waste planners & E.A. • Site leachate not controlled • Multi-Agency meeting • Joint site visit • Huge public concern, political pressure to resolve • January 2003 • Site determination

13. Initial negotiations : Legal situation January 2002 • NOTE: Early days in Part IIA implementation! • Site owner/operator bankrupt – therefore does not legally exist • Property inc. waste management licence held by liquidators • Then disclaimed as ‘onerous property’ under Insolvency Act • Ownership of site reverted to Crown • Escrow fund (for restoration) tied to licence (E.A./site owner) • Planning – nothing to be achieved by enforcement – query re. Crown liabilities • Power generation company on site

14. Initial negotiations: Implications January 2002 • Waste Management legislation not applicable • Part IIA action recommended by E.A. re. controlled waters – potential Special site? • BUT - “Inspection Strategy for Contaminated Land in the Bradford District” Dec. 2001 – identified inspection priorities…

15. Inspection Strategy: Site Specific Priority Factors

16. Initial Negotiations: 2002 • Legal Counsel’s opinion – non-determination defensible where no significant pollutant linkage identified • But if E.A. stopped pumping leachate then SPL could occur…? • Therefore Assessment actions continued

17. Leachate migration

18. Groundwater: Potential migration pathway via compromised landfill liner Cross Section Waste deposits Leachate saturated waste deposits Leachate detection chamber Leachate ingress to LDC Main clay liner Leachate detection layer Rough Rock Flags (Bedrock & Minor Aquifer)

19. Site review: Controlled Waters • Source/Contaminants • Leachate breakout on edges of site with run-off over surface across industrial estate • Groundwater – leachate migration potential via compromised main liner • Potential pollutant linkages & receptors: • Surface water – via drainage systems via sewerage to Manywells Beck • Groundwater – E.A. Landsim modelling

20. Controlled Waters: significance? • Surface water – leachate from breakout diluted on site and during run-off – no significantpollutant linkage • Groundwater – potential pathway due to percolation of leachate via thin basal clay liner – potential significant pollutant linkage • Note – NO proven significant pollutant linkages

21. Assessment Actions • Conceptual site model (CSM) drafted in-house • No proven significant pollutant linkages identified • No risk to human health identified • Determination based on controlled waters resisted

22. Conceptual Site Model: a starting point

23. Assessment Actions: Landfill Gas • BUT concern about landfill gas identified • IMC consultants - commissioned to review and report on potential risks from landfill and mine gases • Potential threat to human health – potential gas migration through fractures in the rocks into • Woodland areas used for informal play by children (including dens) • Hollows in field where livestock shelter in poor weather conditions

24. Den Making in woodland

25. Part IIA & Manywells – key points • Other regimes? • Waste management regime – failed • Planning regime – failed • Viable significant pollutant linkages? • Surface water - pathway to Manywells Beck – not ‘significant’ due to leachate dilution before leaving site • Groundwater - pathway – potentially ‘significant’ over time • Landfill gas – potentially ‘significant’ low likelihood but extreme impact on human health possible in certain conditions

26. Determination process • Note: Not many examples of determination documents available in 2002 • Collation of evidence to confirm SPL • Basic Risk Assessment • Map/plan • Format/Layout = Determination document

27. Determination Document: Page 1

28. Determination Document: SLP1

29. Determination Document: SPL2

30. Determination Document: Gas risk assessment • “Therefore the Council has concluded that the proven presence of landfill gas in the ground surrounding the site, the identification of potential pathways and the presence of identified receptors are sufficient to conclude that there is a significant possibility of significant harm being caused.”

31. Gas concentrations • Methane up to: • 58%v/v in borehole outside site boundary • 14% v/v in dry-stone wall adjacent to boundary • 8%v/v in pinholes in hollows in field • Carbon dioxide up to: • 42%v/v borehole outside site boundary • 24%v/v in dry-stone wall adjacent to boundary • 30%v/v in pinholes in hollows in field

32. Determination Document: Groundwater Risk Assessment • “Therefore the Council has concluded that: • the proven presence of landfill leachate in the leachate detection layer below the basal liner, • the modelled permeability of the secondary liner which may provide a pathway to groundwater, and, • the presence of groundwater beneath the site and of a licenced abstraction point, Manywells Spring, are sufficient to conclude that this land is in such a condition by reason of substances, in, on or under the land that pollution of controlled waters is likely to be caused.”

33. Determination Document: Map

34. Part IIA: Post determination issues • Initial remediation solution – removal of 98K tonnes material from site – practical issues • ‘Project management’ – with PCO/EHO & EHM (not key area of expertise) • E.A. still involved in site pumping leachate therefore division of responsibilities

35. Part IIA: Post determination issues • Neighbouring land owners • Power generation company • Escrow fund - E.A. High Court action • Negotiations with Crown • Site ownership issues

36. Resources: SCA / SCE(R) / CLCP

37. Interaction with E.A. • Waste management licence – disclaimed • Local E.A. waste management and Part IIA officers involved in discussions from start • Special site status investigated • National Capital Programme assessor involved from early in project • Ongoing contact and meetings with assessors

38. The Technical Challenge 1: original option Proposal:- Remove 90,000 m3 of material = 22,000 Wagon movements Issues:- • Sustainability • Environmental Considerations • Cost • Short term fix solution? RISK and Where would it go?

39. Technical Challenge 2: Control required for: • Leachate • Landfill Gas • Stability RISK

40. Technical Challenge 3: what were real problems? Significant Pollutant Linkages (SPLs) • What? • Where? • Why? SAFE site. HSE Involvement REQUIRED CLEARER DEFINITION OF THE PROBLEM TO INFORM THE SOLUTION

41. 2006 WORK Leachate Containment – drains, manholes, pumping Landfill Gas – flare, pipe network Site Investigation – 6 boreholes along spine of tip Security and Safety Assessment, Signing, Fencing and Control

42. Landfill Closure

43. Landfill Processes

44. Processes at Manywells

45. Project team and project development • Early 2007 project team expanded • Office of Government Commerce (OGC) Environmental Advice and Services shortlist • Expression of Interest • Supplier Day • Tender and Tender Evaluation Quality and Price • Appointment of MWH • Partnering – establishment of 6 working groups

46. Manywells Landfill Remediation Project Our aim is… ‘To deliver a safe and sustainable solution with an acceptable landform to a timescale which is minimally disruptive to local communities’. … by using good project management and effective communications

47. Interim Works 2007/08 • AIM – induce settlement through • Control of leachate • Generation of landfill gas • Site works October 07 – May 08 • Value £594k

48. Interim Works 2007/08 • Site investigation - locate liner and leachate leaks • Temporary clay cap - reduce water ingress • Vertical drains - promote drainage of waste mass and improve gas production. • Improve collection and control of landfill gas • Formalise leachate drainage • Increased Defra funding allowed some reshaping and deep drainage trenches