Landfill gas management

Sanitary Landfill and Hazardous waste management

1. Prof. M.R.Ezhilkumar
Assistant Professor
Department of Civil Engineering
Sri Krishna College of Engineering and Technology
Coimbatore
[email protected]
IonlyfeelangrywhenIseewaste.
WhenIseepeoplethrowingaway
thingswecoulduse.–Mother
Teresa
1
17CE413
SOLID AND HAZARDOUS
WASTE MANAGEMENT
3.3 –Landfill gas management

2. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 2
Learning Outcomes
☼Landfill gas
☼Generation
☼Movement
☼Control
3.3 –Landfill gas management

3. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 3
Video Session

4. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 4
Landfill Gas
Stages of Gas Generation
I.Aerobic
II.Anaerobic, non-
methanogenic (acid
anaerobic)
III.Anaerobic,
methanogenic, unsteady
IV.Anaerobic,
methanogenic, steady

5. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 5
Landfill Gas
Stoichiometric Estimate of Potential
Gas Potential
Biochemical Methane Potential

6. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 6
Landfill Gas
Problems with Stoichiometric Estimates
Some fractions are not biodegradable (lignin, plastics)
Moisture limitations
Toxins
Some fractions are not accessible (plastic bags)

7. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 7
Landfill Gas
Estimates of Gas Production Rates
Rapid degradation conditions: 3 to 7 years (4 to 10 L/kg/yr)
Moderate degradation conditions: 10 to 20 years (1.5 t 3 L/kg/yr)
Slow degradation conditions: 20 to 40 years (0.7 to 1.5 L/kg/yr)

8. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 8
Landfill Gas
Gas Enhancement Techniques
Moisture Content
Shredding
Leachate Recycle
Inoculum Addition
Buffer
Nutrient Addition
Temperature

9. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 9
Landfill Gas
Gas Composition -Major Gases
Methane (45 -60 % by volume)
Carbon Dioxide (40 -60 % by volume)
Nitrogen (2 -5 % by volume)
Oxygen (0.1 -1.0 % by volume)
Ammonia (0.1 -1.0 % by volume)
Hydrogen (0 -0.2% by volume)

10. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 10
Landfill Gas
Gas Composition -Trace Gases (less than 0.6 % by volume)
Odor causing compounds
Aromatic hydrocarbons
Chlorinated solvents
Aliphatic hydrocarbons
Alcohols
Polyaromatichydrocarbons

11. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 11
Landfill Gas
Why Bother with Landfill Gas?
Odor
Toxics
Greenhouse Gas
Explosive Gas
Potential Energy Source

12. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 12
Landfill Gas
Landfill Gas Management
• Containment
–Natural barriers
High groundwater table
Streams/Waterbodies tied to
groundwater
Impermeable geologic strata
–Manmade barriers
Composite liner
Composite cover
Cutoff walls
Negative pressure trenches
Positive pressure systems
(Brewers Stadium)

13. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 13
Landfill Gas
Landfill Gas Management
Landfill Gas Collection Systems
–Components
•Gas extraction wells or
trenches
•Gas extraction well heads
•Gas header pipes
•Condensate management
•Drip legs
•Condensate knockouts
•Control valves
•Blower station
•Flare (open or closed)

14. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 14
Landfill Gas
Components of Gas Recovery System
One or more wells placed within the refuse
A header system to connect the wells to the gas pumphousesystem creating
the suction
A flare system providing the opportunity to combust the landfill gas in the event
that the gas is not needed
An end user of the gas

15. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 15
Landfill Gas
Landfill Gas Management
Landfill Gas Collection Systems (continued)
–Objective of system
•Migration control
•Regulatory compliance
•Energy recovery “$”
•Listen to clients needs
•Always consider health and safety

16. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 16
Landfill Gas
Landfill Gas Management
Landfill Gas Collection System Design Steps
–Consider objectives
–Define limits of landfill
• Horizontally and vertically
–Gas extraction wells or trenches
–Layout gas wells
• Shallow wells -small ROI; • Deep wells -large ROI
• Typically 150’ ROI (per NR 500); • Liquid levels in landfill

17. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 17
Landfill Gas
Landfill Gas Management
Landfill Gas Collection System Design Steps (continued)
–Locate gas header pipe
–Establish condensate management
–Adjust gas wells, if needed
–Prepare a well schedule (example)
• 0.5 to 1.5 cfm/slotted foot of pipe
–Determine gas generation and flow

18. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 18
Landfill Gas
Landfill Gas Management
Landfill Gas Collection System Design Steps (continued)
–Header and blower sizing calculations
• Calculate by hand
• Spreadsheet
• Computer model KY GAS (Hardy cross method)
–Condensate calculations
–Select blower flare system

19. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 19
Landfill Gas
Landfill Gas Management
Rules of Thumb for Header Design
•Avelocityof50feetpersecondisthemaximumallowedduringconcurrent
flowconditions
•Avelocityof30feetpersecondisthemaximumallowedduring
countercurrentflowconditions
•Avelocityof30feetpersecondisthemaximumallowedwithincondensate
managementstructures
•Apressuredropof1inchwatercolumnper100feetofheaderisthe
maximumallowedunderanyflowconditions

20. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 20
Landfill Gas
Landfill Gas Management
Rules of Thumb for Header Design (continued)
•Flowconditionswithinaheadermustnotexceedeitherpressurelossnor
velocitylimitations
•10inchesofvacuumrequiredatfurthestextractionwell
•10to20inchlossofvacuumatblowerflarestation

21. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 21
Landfill Gas
Landfill Gas Migration -Wells

22. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 22
Landfill Gas
Landfill Gas Migration -Trench

23. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 23
Landfill Gas
Passive systems

24. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 24
Landfill Gas
Passive Landfill Gas Control

25. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 25
Landfill Gas
Landfill Gas Control

26. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 26
Landfill Gas
Landfill Gas is Typically Extracted to a Blower-Flare Station

27. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 27
Landfill Gas
Gas Extraction Wells
Vertical piping system: installed following the refuse placement
Horizontal piping system:installed as the refuse is placed
Design considerations
•Spacing: zone of influence -apparent zone of vacuum influence around
a well
•Location: site topography, age of refuse, and system expansion over
time
•Depth: refuse depth, leachate mound, and cell construction

28. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 28
Landfill Gas
Gas Extraction Wells
Factors affecting performance of gas extraction system
Daily cover
Elevated or perched liquids
Shallow depth
Sludge or liquid depth
Permeability of final cover

29. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 29
Landfill Gas
Gas Extraction Wells
Passive Wells (wells open to
atmosphere)
Active Wells (wells connected
to a gas extraction system).

30. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 30
Landfill Gas
Vertical Piping System

31. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 31
Landfill Gas
Equilateral Triangular Distribution

32. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 32
Landfill Gas
Types of Collection Wells: Vertical wells

33. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 33
Landfill Gas
Condensate collection and Pump Station
Landfill gas condensate –as gas cools while it is transported through the gas
collection system a liquid is formed (cutting of vacuum to the wells), separated
from gas flow and collected in the low spots of the system
Pumping station reservoir –condensate forced to drain into it from low spots

34. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 34
Landfill Gas
Gas Treatment Methods
Gasflaring–controlledcombustionunit,reducesodorsandmore
environmentallysoundthanpassiveventing,encloseflaresmoreefficientthan
openflares
Gasprocessingandenergyrecovery–gasprocessedbyremovingwater,
carbondioxide,andotherimpurities

35. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 35
Landfill Gas
Oxidation of Methane in Landfill “Bio Cover” (by Methanotrophs)

36. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 36
Landfill Gas
Oxidation of Methane in Landfill “Bio Cover” (by Methanotrophs)

37. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 37
Landfill Gas
Factors affecting gas generation

38. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 38
Landfill Gas
Comparison of Biodegradation Time

39. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 39
Assessment Time
Review
Question
Recommendasuitablelandfillgasmanagement

40. SHWM –Module 3 –SANITARY LANDFILL AND HAZARDOUS WASTE MANAGEMENT Mr.M.R.Ezhilkumar 40