LANDFILL DIRECTIVE

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LANDFILL DIRECTIVE
ENGINEERING REQUIREMENTS (RGN 6)

• ROB MARSHALL
• ENVIRONMENT AGENCY
• ESA WORKSHOP
• 25 NOVEMBER 2002

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Introduction overall objectives

• RGN6 does not apply to SEPA
• RGN6 does not cover location, gas control,
  nuisance and barriers that are included in Annex
  1
• What may be acceptable for GW protection may not
  be acceptable for LFG management
• Two overarching objectives are
• No risk of unacceptable discharge/emission
• structural/physical stability

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Geological barrier

• Includes all material from underside of
  artificial sealing liner to the GW compliance
  point
• Required on base sides - steep walled quarries?
• Modelling needs to include failure/degradation of
  the artificial sealing liner

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Artificial sealing liner

• Presumption that its a geomembrane/DAC
• Could use alternative in low GW vulnerability
  areas
• Not specifically required on side slopes in Annex
  1 - but needs to be risk based and consider LFG

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Leachate management Capping

• Only criteria in Annex 1 is 0.5m thick - system
  needs risk based design and pipework
• Cap required for all hazardous non-hazardous
  sites
• Annex 1 recommendations - risk based design, but
  as minimum require a sealing system and a surface
  water drainage layer

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Landfills that do not pose a hazard

• If RA demonstrates no unacceptable risk (ie inert
  waste, no receptor or no leachate) then no
  requirement for leachate drainage
  blanket/artificial sealing liner
• Also geological barrier requirements may be
  reduced

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Previously deposited waste

• Not going to talk about definition of
  installation today - but it is a critical issue
• Piggybacking - must meet basic rules of no
  unacceptable discharge stability
• Underlying this is the position that a LFD
  compliant liner is not required (if old waste is
  within the PPC permitted area)
• Landfill gas issues still need to be considered

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Groundwater entry

• Prevent GW ingress - being interpreted in a risk
  based manner
• RA needs to satisfy
• stability
• leachate collection
• effectiveness of GW control systems
• operational control
• no unacceptable discharge

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PPC Application Form
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Engineering in the Regulatory Specification

• provide information which essentially gives a
  conceptual engineering design for the site
• table covering most commonly used engineering
  materials
• clay - thickness, hydraulic conductivity,
  consistency limits, shear strength, attenuation
  capacity, design life
• Details of construction quality assurance