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TRANSCRIPT
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Aerobic vs. Anaerobic Bioreactor Landfill Case Study: the New
River Regional Landfill
Presented at SWANA’s 6th Annual Landfill Symposia
San Diego, CAJune 18-20, 2001
Debra R. Reinhart, PhDTimothy Townsend, PhD
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View of drill rig from the landfill’s entrance road.Drill Rig Panorama
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Presentation Overview
• Brief overview of NRRL bioreactor project
• Flammability issues• Cost issues• Moisture balance issues• Waste degradation issues• Process control impacts
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Project Location
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Cell 3Cells 1 & 2
Bioreactor
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Bioreactor Components
• Leachate Collection System Modifications
• Leachate/Air Injection• Gas Collection• Geomembrane Cap
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• Three Wells
• Spacing 3-5 ft
• Maintain 10 ft distancefrom top of sand drainage layer to bottom of the well
Top of Landfill
Top of Sand DrainageBlanket
10 ft
Cluster Well Sketch
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Bioreactor Gas Extraction
Cell 1Cell 2
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GeomembraneCap
Gas
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Monitoring
• Leachate• Landfill Gas• Waste Properties• Settlement
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Instrumentation
• Head on Liner• Leachate Flow• Landfill Temperature• Landfill Moisture Content
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Moisture Sensors
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New River Regional Landfill Bioreactor Demonstration ProjectCross Section on Injection Cluster Wells C8 (x=600)
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-100 0 100 200 300 400 500 600 700 800 900
Y
Elev
atio
n
Landfill Surface Well Bottom Safety Zone Bottom Liner
10 ft
CN8CL8
CJ8 CH8 CF8CD8
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0 100 200 300 400 500 600 700 800
0
100
200
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New River Regional Landfill Bioreactor Project
New River Regional LandfillLocation: Union County, Florida
Monitoring WellInjection Well
Bioreactor Landfill BoundaryAccess Road
Legend General Temperatute SketchInjection Wells Sheet Nº
1/4
File: temp def sketch.srf Date: 05/30/01Scale: 1:125Units:English
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Scale: 1:50Units:English
New River Regional Landfill Bioreactor Project
New River Regional LandfillLocation: Union County, Florida
Monitoring WellInjection Well
Bioreactor Landfill BoundaryAccess Road
Legend Temperature MapInjection Wells B (~40-50 ft deep) Sheet Nº
3/4
File: Temperature.srf Date: 05/30/01
300 350 400 450 500 550
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CN2
CL2
CJ2
CH2
CF2
CD2
CC3
CF3
CG3
CI3
CK3
CM3
CO3
CN4
CL4
CJ4
CH4
CF4
CD4
CC5
CE5
CG5
CI5
CK5
CM5
CO5
CN6
CL6
CJ6
CH6
CF6
CD6
CC7
CE7
CG7
CI7
CK7
CO7
CN8
CL8
CJ8
CF8
CD8
100102104105106108110112114115116118120122124125126128130132
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0
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7080 85 90 95 100 105 110 115 120 125 130
Temperature (degrees F)
Dep
th fr
om
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p o
f La
ndfil
l (ft
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TP3 TP2
TP4 TP1
TP4 TP5
New River Regional LandfillTemperature Profiles
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Monitoring Probe
InstrumentationPackageClay
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Instrumentation and Injection Wells
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Anaerobic vs. Aerobic Landfilling
• Flammability• Moisture Balance• Process Control• Degradation Pathways• Waste Degradation• Costs
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02468
10121416182022
0 5 10 15 20 25% Methane
% O
xyge
nMixtures that can
not be formed
ExplosiveRange
Not capable offorming flammablemixtures with air
Capable of forming flammablemixtures with air (contains too
much methane to be in explosive range)
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02468
10121416182022
0 5 10 15 20 25 30 35 40 45 50 55% Methane
% O
xyge
n
Arid Region Landfill
Air
Aerobic Landfill
Anaerobic Landfill
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Moisture Issues: Anaerobic Decomposition
→+ OHOHC 25106 24 33 COCH +
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Moisture Issues: Aerobic Decomposition
→+ 25106 6OOHC OHCO 22 56 +
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Aerobic Landfill
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Moisture Balance
Moisture,gpm/acre
Aerobic Anaerobic
Loss/Gain –Biodegradation
0.51 0.24
Removed inExhaust Gas
1.16 0.21
Required Input 0.65 0.45
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Measure GasConcentration
Plot data Immediate-ly stop airinjection
Gas inexplo-sive
range.
Gasoutside ofexplosive
MonitoringPoint inAnaerobic?
MonitoringPoint inAerobic
O2 >2 %CH4 2 %
ConsiderIncr. Flow
Decrease Air
YesNo
O2 10%
Control Diagram
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MeasureTemperature
T < 140 °F
T > 140 °FT < 160 °F
T > 160 °FT < 170 °F
T > 170 °F
Possible concern. Check gas concentrations.If anaerobic → Add leachateIf aerobic → Reduce air flow rate. Track the rate oftemperature increase of this area. If a rate of 1°F perday (weekly average) is exceeded, stop air injectionand add leachate/water.
Temperature may be below optimum. Investigateand revise operations as desired. Not a safety hazard.
Optimum conditions. Operate and monitor asscheduled.
Condition of concern. Stop air injection. Addleachate at permitted amount only, or request thatDEP allows more liquid volume injection.
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Waste Degradation
• Different pathways– Some compounds are recalcitrant under aerobic
conditions and degrade under anaerobic conditions and vice versa
• Energy yields– Aerobic reactions yield more energy, this can lead
to elevated temperatures under low MC• Byproduct formation
– H2S– Methane
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Waste Stabilization
0.00
10.00
20.00
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40.00
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70.00
80.00
0 10 20 30 40 50
Time, years
CO
D, g
/L
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Leachate COD Reduction Half-Lives
Scale OperatingRegime
COD Half-Life,Days
Laboratory Anaerobic Wet 26 – 157Laboratory Anaerobic Conventional 150 – 1369Laboratory Semi-aerobic Wet 24Laboratory Semi-aerobic Conventional 26
Pilot Anaerobic Wet 117Pilot Anaerobic Conventional 99Full Anaerobic Wet 285 – 383Full Anaerobic Conventional 3650
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Cost Issues
Aerobic– Energy
Requirements– Loss of methane– Potential GHG
emission offset credits
– Additional moisture requirements
Anaerobic– Gas
collection/treatment– Additional leachate
treatment
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Energy Considerations –Aerobic Landfill
• Blowers– Push air through landfill– 4.75 x volume of anaerobic gas production– NRRL Aerobic Energy Requirements 12 x
Anaerobic
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Conclusions• Power requirements are twelve times higher for an
aerobic bioreactor as compared to the anaerobicbioreactor.
• Aerobic bioreactor moisture requirements are 29%higher.
• Due to the presence of diluent gases in aerobicbioreactor gases, flammable conditions are unlikelyto develop, particularly if process conditions ensurelow oxygen levels.
• The addition of water and air significantlyaccelerations the rate of reduction of organic materialin leachate.
• Oxygen content and internal temperature are criticalcontrol components for aerobic and anaerobicbioreactors
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Schedule (Estimated)
• Permit Award: December 2000• Instrumentation Installation: Spring
2001• Bioreactor Construction: Fall 2001• Begin Bioreactor Operation: Late
2001
Aerobic vs. Anaerobic Bioreactor Landfill Case Study: the New River Regional LandfillDrill Rig PanoramaPresentation OverviewSlide Number 4Slide Number 5Slide Number 6Bioreactor ComponentsCluster Well SketchBioreactor Gas ExtractionGeomembrane�CapSlide Number 11MonitoringInstrumentationMoisture SensorsSlide Number 15Slide Number 16Slide Number 17Slide Number 18Monitoring ProbeInstrumentation and Injection WellsAnaerobic vs. Aerobic LandfillingSlide Number 22Slide Number 23Moisture Issues: Anaerobic DecompositionMoisture Issues: Aerobic DecompositionAerobic Landfill Moisture BalanceSlide Number 28Slide Number 29Waste Degradation Waste StabilizationLeachate COD Reduction Half-Lives Cost IssuesEnergy Considerations – Aerobic LandfillConclusionsSchedule (Estimated)