Sustainable Landfills: The Future of Land Disposal

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Sustainable Landfills The Future of Land
Disposal of Municipal Solid Waste (MSW)
Patrick Hettiaratchi Associate Professor,
Department of Civil Engineering CEERE (
Center for Environmental Engineering Research
Education) Faculty of Engineering, University of
Calgary Chair, Environmental Engineering
Division (EED), Canadian Society for Civil
Engineering (CSCE) April 17, 2003
Presentation to CSCE Calgary Section
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Sustainable Landfills
Landfills that are designed and constructed to
achieve Sustainable Development (SD), or
designed and constructed using SD principles
Sustainable Development is development that
meets the needs of the present without
compromising the ability of future generations to
meet their own needs (1987 UN Commission on SD
Bruntland Report)
Sustainable Development is Common-Sense
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Sustainable Development Engineering
SD is Common-Sense .
Engineering is common-sense application of
technology to meet human needs (current and
future)
Engineers have no choice, but to apply SD
principles in their practice

• Sustainable Infrastructure

• Sustainable Transportation

• Sustainable Landfills

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Sustainable Landfills
Landfills
designed and constructed using SD principles
SD Principles.
Recycle (or recovery of Recyclables)
Recovery (of Energy and Compost)
Current Landfilling Practice.

• Is this Sustainable?

• Are we applying SD principles in Landfill
  development now?
• (you be the judge..)

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Open Dumps, Sanitary Landfills and Sustainable
Landfills a Natural Progression??
Past We started with Open Dumps.. (until
someone showed that it is not a good practice)
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• Today We have converted Open Dumps to Sanitary
• Landfills ..
• Conventional dry-tomb type Sanitary Landfills
  are
• designed and constructed to eliminate problems
• associated with Open Dumps

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Problem Landfill Leachate

• Leachate is garbage juice or an aqueous
  liquid produced within the landfill

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Landfill Construction
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Leave it Alone !!!!!
R I P
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Problems with the Dry-tomb Sanitary Landfillling
Approach

• Un-sustainable??? Loss of Space. Need to find
  new space every few years (Toronto, Edmonton)

• Long-term liability Need to monitor potential
  impact for a long- time (until waste stability is
  achieved)

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Zambisa Landfill (Quito, Ecuador)
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Zambisa Landfill (Quito, Ecuador)
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Sustainable Landfill
The Concept

• Holistic approach (not piece-meal)

• Increase biological activity in landfill cell
  possible to
• extract large quantities of gas in a short
  period of time

• Stabilize the waste quickly (Anaerobic and
  Aerobic)

• Mine the cell, and extract recyclables
  compost

• Reuse space

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Sustainable Landfill
Anaerobic Reactor
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(No Transcript)
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Sustainable Landfill
Aerobic Reactor
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Sustainable Landfill Operation (Calgary Biocell
Concept)
Anaerobic Year 2
Anaerobic Year 1
Anaerobic Year 3
Mining/ Space Recovery Year 6
Aerobic Year 5
Aerobic Year 4
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Problems to Resolve
Moisture Distribution Within the Cell
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Leachate Pools Created by over-zealous
Leachate Recirculation
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Problems to Resolve
Surface Gas Emissions

• Could occur during construction of the biocell
  (may take 1 or 2 years to completely fill a cell)

• Significant quantities can escape from surface
  even with
• a gas capture system
• example Loma Los Colorados Landfill, Chile

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Loma Los Colorados Landfill, Chile
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Loma Los Colorados (contd)
Gas Wells
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Landfill Gas Incinerator
CH4 burned 85 tonnes/year (or 330 m3/d)
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Loma Los Colorados Bioreactor Landfill
Landfill Methane Budget
Total CH4 emitted/burned 17,040 tonnes/year
(exclude leachate pool emissions)
More than 75 of the produced methane gas
escapes across the cover soil (worth about 3
million/year in the open Carbon market)
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Calgary Sustainable Biocell

• Pilot Project (1 hectare 50,000 tonnes of waste)

• Partners/Participants City of Calgary,
  University of Calgary and Stantech Consultants

• Mitigation Measures

• Biocap, or Methane Oxidation Layer (MOL), to
  control methane gas emissions during
  construction and operation

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Landfill Bio-Caps or MOLs

• A new concept
• Use a naturally occurring bacteria to convert
  methane

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Biofiltration of CH4
Microbially mediated oxidation of CH4 is carried
out by methanotrophic bacteria
(Methylomonas methanica)
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CH4 Oxidation in Landfill Caps
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Conclusions

• Waste disposal has progressed from open dumps
  (in the past) to sanitary landfills (in the
  present). Sustainable Landfills could be the
  future.
• Sustainable landfilling follows a holistic
  approach. It is consistent with the current
  thinking (in terms of SD).
• Technical challenges need to be overcome,
  before Sustainable Landfill concept could be
  universally applied.
• Civil Engineers should take a lead to role to
  ensure SD principles are adopted in the practice
  of land disposal.

Thank You!