Biogas and Leachate Treatment Experiences in Ireland

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Biogas and Leachate Treatment Experiences in
Ireland Margaret Heavey, Head of Landfill
Operations Gabriel Dennison, Technical Director
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Greenstar (Ireland) who we are

• Established 1999
• Irish owned and managed
• 600 employees in 25 locations
• Irelands largest waste management company
• Recycling, Composting, Residual Landfill /
  energy recovery
• Manages household, commercial and industrial
  (CI) waste
• Operates 4 of Irelands 5 private non-hazardous
  landfills
• Industry award for National Recycler of the year
  2006

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Presentation Format

• Regulatory issues that affect leachate and
  Biogas planning
• General summary of biogas treatment technologies
• Landfill biogas progress in Ireland
• Greenstars experiences - biogas
• General summary of leachate treatment
  technologies
• Leachate treatment in Ireland
• Greenstars experiences - leachate

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Biogas / Leachate - Regulatory Issues

• EU landfill directive
• Kyoto Agreement
• EPA buffer guidance restrict landfills to
  relatively remote locations
• Planning restrictions in proximity to
  significant receiving water bodies
• Failure by local authorities to close small old
  landfills as planned
• Planning uncertainty due to slow rate of
  progress with incineration plans
• Capacity constraints - Municipal Waste Water
  Treatment Plants
• Capacity constraints - National Electricity Grid
• Electricity prices

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Landfill Biogas Technologies

• Landfill gas typically 50 - 75 Methane
• Utilisation guide limits gt200kt, gt25 organic
  gt4m depth gt 50 CH4
• Most common utilisation technology - internal
  combustion engines
• Using boilers to generate heat is also used but
  less common
• Landfill gas as a vehicle fuel pilot stage
  research in USA
• Pre-treatment of gas corrosive compounds-
  moisture content
• Waste acceptance procedures and filling methods
• Flaring of gas using Enclosed flares

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Biogas Technologies - Ireland

• Many small local authority landfills practise
  passive venting
• Most common gas technology is flaring
• Due to landfill size and remoteness only 8
  landfills generate electricity
• High costs of electricity grid connection make
  below 1MW unviable
• Landfills lt 100,000 tpa unviable due to grid
  costs
• 18 months to 3 years electricity grid
  application process duration
• High cost of upgrading electricity network over
  long distances
• Landfill gas planning uncertainty associated
  with landfill size restrictions
• Large scale landfills have better gas generation
  efficiencies

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Biogas Utilisation Greenstar experience

• KTK landfill, Co Kildare, Ireland
• 275,000 tpa No food or green waste
• leachate recirculation
• flaring and utilising 7,500 m3/ hr gas
• Generating 3.75 MW of electricity
• limiting factor is electricity grid
• Joint Venture Greenstar Gas Energy
• 25 owned GAS GmbH Germany
• 75 owned Greenstar

Greenstar 4.5 MW Utilisation Plant, KTK landfill
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Biogas Utilisation Greenstar experience

• June 2006, engine M1 suffered catastrophic
  failure after less than 1 year
• Investigation of other two engines M2 and M3
  showed similar symptoms
• Build up of siloxane deposits on cylinder liners
• Piston and liner seized leading to failure
• November 2006 dewatering / chilling treatment
  system installed
• Increased maintenance regime

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Landfill Leachate Worldwide

• MSW leachate worldwide has similar
  characteristics (Enviros,UK 2005)
• Climatic conditions (rainfall, temperature)
  affect volumes and treatment
• Discharge consent limits vary determine level
  of treatment required
• Young leachate (acetogenic) is different to
  older (methanogenic) leachate

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Leachate Treatment Technologies

• Most common treatment in Europe involves
  Municipal Waste Water Treatment Plants (MWWTP)
• On-site typically includes aerobic treatment to
  reduce BOD and NH4-N
• Discharge consent limits vary countries /sewer
  discharge / surface water
• Ammonical Nitrogen removal (nitrification) can
  be temperature sensitive
• Nutrient removal (nitrates) may be a requirement
  of the regulatory authority.
• Biological denitrification, air stripping,
  reverse ozmosis, reed bed polishing
• Hard COD may need to be removed ( activated
  carbon, ozonation, UV )
• Discharge of COD subject to toxicity testing.
• Leachate evaporation technologies used in France
  and Finland
• Leachate discharged to sewer is likely to need
  methane removal

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Leachate Treatment Ireland

• 3 purpose designed Leachate Treatment Plants in
  Ireland
• 1 extended aeration 1 SBR technology 1
  Biofiltration using peat.
• EPA set discharge limits on BOD, NH4-N, pH, SS
• All landfills in Ireland are currently using
  MWWTPs to treat their leachate
• Road transportation distances of gt 20km are
  typical
• Local authorities do not charge themselves
  leachate treatment costs
• Many MWWTPs need upgrading and capacity
  increases
• No national policy on effluent treatment charges
  at MWWTPs prices vary
• Since May 2007 MWWTPs are to be regulated by the
  EPA

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SBR system, Arthurstown Landfill Co. Kildare
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Greenstar Leachate Management

• Due to planning limitations landfills are not
  near receiving waters
• Recirculation of leachate to promote
  stabilisation and gas production
• Currently treating the small volumes for
  disposal at MWWTPs
• Investigating pre-treatment and centralised
  alternatives
• Difficult to plan long-term solution until upper
  tonnage limit known
• Aftercare planning the walk away solution
• Sustainability is the key

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Recommendations

• Ireland needs to close down old inefficient
  landfills lt 50,000 tpa
• In the short-term Ireland needs to facilitate
  the development / expansion of existing modern
  landfills to a scale which will economically
  support bioenergy utilisation and efficient
  leachate management.
• Adopt findings of Eunomia (UK) 2007 report
  Waste Policy Planning and Regulation in Ireland
  recommending MBT and landfill as an interim
  alternative to incineration for Ireland to meet
  EU landfill diversion targets
• Regulation needed to encourage the source
  segregation of gypsum
• Re-examine Inert Landfill limits for wastes
  containing sulphates
• Investment in national waste water treatment
  infrastructure
• Investment in national electricity grid
  financial instruments

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www.greenstar.ie Thank You