Sustainable Landfills: The Future of Land Disposal of Municipal Solid Waste (MSW)
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Transcript of Sustainable Landfills: The Future of Land Disposal of Municipal Solid Waste (MSW)
Sustainable Landfills: The Future of Land Disposal Sustainable Landfills: The Future of Land Disposal of Municipal Solid Waste (MSW) 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
Sustainable Landfills Landfills that are designed and constructed to achieveSustainable Development (SD), or
……… … designed and constructed using SD principlesdesigned and constructed using SD principles
Sustainable Development is Sustainable Development is “development that meets the “development that meets the needs of the presentneeds of the present without compromising the ability of without compromising the ability of
future generationsfuture generations to meet their own needs to meet their own needs (1987 UN (1987 UN Commission on SD; Bruntland Report)”Commission on SD; Bruntland Report)”
Sustainable Development is “Common-Sense”Sustainable Development is “Common-Sense”
Sustainable Development & Engineering Sustainable Development & Engineering
SD is Common-Sense …….SD is Common-Sense …….
Engineers have no choice, but to apply Engineers have no choice, but to apply SD SD principles in their practice principles in their practice Sustainable InfrastructureSustainable Infrastructure
Sustainable TransportationSustainable Transportation
Sustainable Sustainable LandfillsLandfills
Engineering is “common-sense application of Engineering is “common-sense application of technology to meet human needs (current technology to meet human needs (current and future)”and future)”
Sustainable Landfills Landfills…… Landfills……
……… … designed and constructed using SD principlesdesigned and constructed using SD principles
SD Principles….SD Principles….
Current Landfilling Current Landfilling Practice….Practice…. Is this Sustainable? Is this Sustainable? Are we applying SD principles in Landfill development now? Are we applying SD principles in Landfill development now?
(you be the judge…..) (you be the judge…..)
Reduce Reduce ReuseReuse
Recycle (or recovery of Recyclables)Recycle (or recovery of Recyclables)Recovery (of Energy and Compost)Recovery (of Energy and Compost)
Open Dumps, Sanitary Landfills and Open Dumps, Sanitary Landfills and Sustainable Landfills:Sustainable Landfills: a Natural Progression??a Natural Progression??
Past:Past: We started with Open Dumps…….. (until someone showed that it is not a good practice)
ButBut, still common practice in most developing countries!!!!!
Today: We have converted Open Dumps to Sanitary Today: We have converted Open Dumps to Sanitary Landfills …..Landfills ….. Conventional “dry-tomb type” Sanitary Landfills are designed and constructed to eliminate problems associated with “Open Dumps”
Prevention of GW contamination with bottom liner systemsPrevention of GW contamination with bottom liner systems
Leachate is “garbage juice” or an aqueous liquid produced within the landfill
X-section along the length of the landfill
Stream
Area A
Area C
Area BWorking Face (Area D)
Leachate can contaminate Groundwater (unseen) or Surface Water (obvious)
““Dry Tomb” landfillDry Tomb” landfill
Problem: Landfill LeachateProblem: Landfill Leachate
Landfill ConstructionLandfill Construction
Final cover
Daily cover
Intermediate cover
Leave it Alone !!!!!Leave it Alone !!!!!
R I PR I P
Problems with the Dry-tomb Sanitary Problems with the Dry-tomb Sanitary Landfillling ApproachLandfillling 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)
Liability associated with landfill gas:
Landfill gas contains CH4 and CO2 (both are GHGs)1/3 of anthropogenic CH4 in USA come from Landfills
If gas is extracted (for energy recovery)…. Possible to minimize concerns In most cases, gas production is low; not economical to
extract methane gas for energy recovery Gas can be a major hazard (Ecuador example)
Zambisa Landfill (Quito, Ecuador)
X-section along the transverse direction
Zambisa Landfill (Quito, Ecuador)
X-section along the transverse direction
Sustainable LandfillThe Concept:The Concept: Holistic approach (not “piece-meal”)
Stabilize the waste quickly (Anaerobic and Aerobic)
“Mine” the cell, and extract recyclables & compost
Reuse space
Increase biological activity in landfill cell; possible to extract large quantities of gas in a short period of time
Sustainable LandfillSustainable Landfill
Anaerobic ReactorAnaerobic Reactor
Sustainable LandfillSustainable Landfill
Aerobic ReactorAerobic Reactor
AerobicYear 5
AerobicYear 4
AnaerobicYear 3
AnaerobicYear 2
AnaerobicYear 1
Mining/Space Recovery
Year 6
Sustainable Landfill OperationSustainable Landfill Operation(Calgary Biocell Concept)(Calgary Biocell Concept)
Problems to ResolveProblems to Resolve
Moisture Distribution Within the CellMoisture Distribution Within the Cell
What We Want…..
What We Get
Leachate Pools: Leachate Pools: Created by “over-zealous” Leachate RecirculationCreated by “over-zealous” Leachate Recirculation
Problems to ResolveProblems to Resolve
Surface Gas EmissionsSurface 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 witha gas capture systemexample: Loma Los Colorados Landfill, Chile
Loma Los Colorados Landfill, Chile
Disconnected gas wellConnected gas well
25
8
26
1
29
56
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15
185
31
19
5730
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27
14
7
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2313
1721
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90 metres
Gas Wells
Loma Los Colorados (contd…)
Landfill Gas Incinerator
CH4 burned= 85 tonnes/year (or 330 m3/d)
Total CH4 emitted/burned = 17,040 tonnes/year (exclude “leachate pool” emissions)
Loma Los Colorados Bioreactor LandfillLoma Los Colorados Bioreactor Landfill
More than 75% of the “produced methane gas” escapes More than 75% of the “produced methane gas” escapes across the cover soilacross the cover soil
(worth about $3 million/year in the “open Carbon (worth about $3 million/year in the “open Carbon market”)market”)
Landfill Methane Budget: Landfill Methane Budget:
Calgary Sustainable BiocellCalgary 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
Landfill Landfill Bio-CapsBio-Caps or MOLs or MOLs
A new concept
Use a naturally occurring bacteria to convert methane
CH4 & CO2Generation
CO2Emissions CH4 & CO2
EmissionsCommercialRecovery
CH4 & CO2 LateralMigration
Oxidation In landfill cover (Methanotrophs)
Biofiltration of CH4
Microbially mediated oxidation of CH4 is carried out by methanotrophic bacteria
(Methylomonas methanica)
CHCH44 Oxidation in Landfill Caps Oxidation in Landfill Caps
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0 50 100 150 200 250 300
Time (days)
% M
etha
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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!Thank You!