Cost Effective Leachate Treatment Options for Restored Landfills A Case Study of Two Landfills

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Cost Effective Leachate Treatment Options for
Restored Landfills A Case Study of Two
Landfills
BSc, MSc Cathriona Cahill (RPS Consulting
Engineers) BA, BAI Cora Plant (RPS Consulting
Engineers)
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Overview

• Legislative Background
• Restoration Aftercare
• Landfill Leachate Treatment
• Case Studies
• Dungarvan Landfill (Closed, unlined)
• Integrated Constructed Wetlands
• Kyletalesha Landfill (Active, lined unlined)
• Willow Short Rotation Coppice
• Conclusions

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Legislative Background

• 1993 EPA were established
• 1996 Waste Management Act
• Procedures for Waste Licensing
• Restoration Aftercare
• Env. Monitoring/Management
• 30 years!
• The Waste Management (Licensing)(Amendment)
  Regulations, 2002
• maintain a financial provision for the closure,
  restoration and aftercare of the facility

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Restoration Aftercare Costs

• Continued monitoring and reporting to the agency
• Maintain a landfill gas management system
• Maintain effective leachate treatment disposal
  mechanisms
• Challenges!

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Landfill Leachate Treatment

• Complete on-site treatment
• On-site treatment to remove methane and
  subsequent disposal to sewer
• Tankering from on-site storage area
• Dilute Disperse Principle

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Dungarvan Landfill

• Co. Waterford
• 6 hectares (5 ha waste)
• Commenced operation in 1968
• Dilute Disperse Principle (unlined)
• Waste Licence 2002
• Closed in 2004
• Little Revenue

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Restoration Aftercare Plan

• Framework
• Installation of Integrated Constructed Wetlands
  into the Capping System
• Treatment of leachate
• Cost Effective
• Low Maintenance
• Area of Nature Conservation
• Public Amenity Area

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Integrated Constructed Wetlands

• Design Approach developed by DoE (NPWS)
• Shallow ponds
• Thrive conc. 100mg/l ammonium
• 15 18 dilution prior to treatment
• 125-200m3 day
• 1m3 requires 100m2 ICW
• Discharge to adjacent River Colligan
• High Assimilative Capacity
• Tidal

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Design Approach

• Incorporate ICW into Capping System
• Landscape fit
• 2.3ha available ICW
• Cost savings on installation of capping system
• Safely Sealed System
• Leachate Control System
• Alarm system
• Restrict uncontrolled emissions to River Colligan

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Programme

• EPA have accepted the concept of ICW
• Waste Licence Review
• Emission Limit Values
• Emissions to River Colligan
• Management and Maintenance Plans
• Mass Balance Calculations
• Capping commenced in July 2007
• Establish ICW in 2008

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Kyletalesha Landfill

• Co. Laois, Midlands
• Licensed 47,100 tonnes/annum
• Site area
• Approx 70 hectares
• Lined unlined cells
• Combination of Leachate Treatment on-site
  Tankering off-site

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Leachate Management Plan

• Assessment of Existing Practices
• Assessment of Disposal Options

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Leachate Disposal Mechanisms

• Leachate Infrastructure
• Gravity Pumped Systems
• Lined Storage Lagoon (2,800m3) pre 2007
• Unlined Storage Lagoon (7,000m3) pre 2007
• Leachate Storage Tank (900m3) 2007
• Leachate Disposal
• Peat Treatment Beds (1999 - 2006)
• Tankering off-site (current)

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Disposal Options

• Willow Short Rotation Coppice
• Treatment on-site
• Removal of harmful constituents
• Possible source of revenue
• Low management
• Compact system
• Lined system
• Completely Enclosed

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Suitability for Kyletalesha

• Limiting Factors
• Rate of Adsorption
• Typically 4,500m3/hectare/annum
• Longer growing season in Ireland 10 months
• Chlorine
• 940 Kg/annum

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Leachate Composition
Maximum Leachate Generation and Cl concentrations
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Application Rates
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Conclusions

• Cost Effective Solution for the disposal of
  leachate dependant on the following criteria 
• Available space
• Concentration of the limiting factors in the
  leachate and the dilution capability requirements
  
• Availability of discharge point
• The stage of landfill operation active or
  capped
• Foundations are designed and incorporated in the
  capping system