The processes effectiveness depends on the age of landfill
Landfill age < 5 years (young) 5-10 years (medium)
>10 years (Old)
Leachate type Biodegradable Intermediate Stabilized
Processes Treatment efficiency
Biological treatment Good Fair Poor
Treatment Process effectiveness based on landfill age
Biological treatment Good Fair Poor
Adsorption Fair-Poor Good-Fair Good
Coagulation-floculation
Fair-Poor Good-Fair Good
Chemical Oxidation Fair-Poor Fair Fair
Membraneprocesses (RO)
Fair Good Good
LandfillBlowerFlare
Station
Gas Wells
Note:Must Drain
Condensate
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(a) Must minimize infiltration (b) Must act as a hydraulic barrier (similar to that in a
liner)(c) Must enhance surface run-off( )
(d) Must prevent surface erosion(e) Must prevent landfill gas from escaping(f) Must support vegetation(g) Must exhibit long-term slope stability(h) Must withstand surface exposure to loads (eg.
traffic) and environmental conditions.
HW Landfill (India) MSW Landfill (India)
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Cost of geo-membrane: 50 cents to 1$ per square feetCost of geo-textiles: 50 cents per square feetCost of geo-nets: 1$ per square feet
Tipping fee in US: 20$ to 50$ per tonne of MSWLandfilling cost in India: Rs. 200 to 500per tonne of MSW, Rs. 2000 per tonne of Hazardous Wastes
MSW is to be processed first for recoveryComposting or vermi-composting
Long time for stabilization of wasteLandfill area is blocked for about a centuryyLeachate is to be treated and managed
Any alternative ?? Yes…………. Go for another concept
Landfill is considered to be a big bioreactorNo processing of biodegradablesLeachate is collected; but circulated back to the landfilllandfillWaste stabilization is much faster
Aerobic – 5 to 8 yearsAnaerobic – 8 to 12 years
Landfill area is available for re-use quicklyLandfill becomes ‘sustainable’
YES. Bioreactor landfills are not allowed in India nowBut there are on-going attempts to make bioreactor landfills in India
Research is on in this area:University of FloridaAnna UniversityIIT Delhi
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Waste+ Water
ExhaustGas
Air Leachateor Water
+ Microorganisms
“A bioreactor landfill is a controlled landfill or landfill cell where liquid and gas conditions are actively managed in order to accelerate or enhance biostabilization of the waste. The b l df ll f l hbioreactor landfill significantly increases the extent of organic waste decomposition, conversion rates, and process effectiveness over what would otherwise occur with the landfill.”
SWANA Bioreactor Committee
Composite linerAppropriate density of MSWAppropriate daily coverLeachate recirculation systemLeachate recirculation systemActive gas collection systemAppropriate final cover systemCompetent landfill operator
Important factors:
Storm water managementmanagement
Leachate storage
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Increased gas production during a shorter time frame may make the lu
me Bioreactor Landfill
yeconomics of landfill gas to energy more attractive
0 10 20 30 40Time (Years)
Gas
Vo
Traditional Landfill
Time (Years)
If leachate is added at too great of a rate, leachate breakouts and seeps can occur.
Even under normal operating conditions, seeps can occur because of nature of waste and cover soil in a landfill.
Problems with seeps:Off-site leachate migration
Odors
Vectors
Path for gas emission
Interception of leachate by highpermeability cover layers and subsequent transmission of leachateto the side slopeof the landfill can result
High PermeabilityCover Soil
Leachate Seep(Outbreak)
in seeps
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Interception of leachate by lowpermeability cover layers and subsequenttransmission of leachate to the side slopeof the landfill can result in seeps
Lesson 9, Slide 41
Low PermeabilityCover Soil
Leachate Seep(Outbreak)
Excessive pore water pressures in a landfill can lead to instability problems.
Strength of waste may become reduced following decomposition.
If uncontrolled, increased gas production from bioreactor operation
Bioreactor landfills may require different types of gas collection systems compared to traditional landfills (wells can become flooded).
When methane is mixed with the right amount of oxygen, an ignited flame can be sustained.
Most landfill gas as it exists in the landfill, a Most landfill gas as it exists in the landfill, a gas well or an extraction pipe (≈ 50% CH4, 50% CO2), does not contain enough oxygen to support a flame. It is not explosive.
Only when the gas is mixed with the appropriate amount of air can a flame occur (5 to 15 % by Volume)
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Initial capital costs and operation costs may be greater for bioreactor landfills compared to those of traditional landfills
At most operations this can be offset by the gains as described previously
Vertical Injection Cluster Wells
Use multiple smallpdiameter wells.
Long-term sustainabilityLiquids managementAirspace recoveryAerobic vs anaerobicAerobic vs. anaerobicHeterogeneity of wasteGeotechnical Stability
Thanks to
Dr. Dinesh KumarMunicipal Corporation of Delhi
Prof. Manoj DattaIndian Institute of Technology, Delhi
