Landfill Leachate: Limit Generation, Control Disposal Sam Cooke, PE April 20, 2018 1
SCS ENGINEERS
Agenda
• Landfill Leachate Issues
• Limit Generation of Landfill Leachate•Examples• Upstream Leachate Issues
• Upstream Leachate Solutions
• Control Disposal of Landfill Leachate•Case Studies• Leachate Treatment (Biological/Filtration)
• Leachate Evaporator
• Deep Injection Well
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SCS ENGINEERS
Landfill Leachate Issues• Leachate generation reduction challenges
•Abundance of precipitation
• Side slope erosion
• Leachate seeps
• Large working faces
•Overcoming improper design
• Undersized storm water controls
• Leachate treatment challenges
• Being cut-off by the Publicly Owned Treatment Works (POTW)
• Costs to dispose (hauling, piping, pre-treatment, surcharges)
• Regulations (TMDLs, emerging contaminants, etc.)
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SCS ENGINEERS
Landfill Leachate Issues
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Example – Landfills in arid areas can also have issues• Not much precipitation at this
landfill facility
• Major leachate issues still exist
• Addressed by recirculation,
evap. ponds, dust control
• High moisture in wet waste
• Wastewater bio-solids
• H20 gets squeezed out
• What would you do?
SCS ENGINEERS
Storm Water Issues:Top deck and side slope
engineering
Possible Solutions:Top deck maintenance
Down slope pipes
Rock chutes (rip rap)
Diversion/tack-on berms
Limit Leachate Issues Through Proper Engineering & OM&M
SCS ENGINEERS
Storm Water Issues:Top deck and side slope
engineering
Possible Solutions:Top deck maintenance
Down slope pipes
Rock chutes (rip rap)
Diversion/tack-on berms
Limit Leachate Issues Through Proper Engineering & OM&M
SCS ENGINEERS
Leachate Seep Issues:Placing final cover
Cell design
Waste placement
Possible Solutions:Limit working face
Limit lateral flow within waste
Manage storm water
Balance leachate recirculation
Limit Leachate Issues Through Proper Engineering & OM&M
SCS ENGINEERS
Leachate Seep Issues:Placing final cover
Cell design
Waste placement
Possible Solutions:Limit working face
Limit lateral flow
Manage storm water
Balance leachate recirc.
Limit Leachate Issues Through Proper Engineering & OM&M
SCS ENGINEERS
Leachate Seep Issues:Cover problems
Storm water issues
Slope maintenance
Possible Solutions:Limit working face
Limit lateral flow
Manage storm water
Balance leachate recirc.
Limit Leachate Issues Through Proper Engineering & OM&M
SCS ENGINEERS
Infrastructure failures:Differential settlement
Improper design
Improper maintenance
Landfill capacity issues
Possible Solutions:Expansion joints
Expand infrastructure
Maintain system
Limit Leachate Issues Through Proper Engineering & OM&M
SCS ENGINEERS
Managing LF Extractions(So many “straws”):
Landfill gas collection
Well derived liquids
collection
Leachate collection
Vertical and horizontal
Other Issues:OM&M
Well-derived liquids
Different chemistries
Limit Leachate Issues Through Proper Engineering & OM&M
SCS ENGINEERS
Pump & Conveyance
Line Fouling:Microbiological build-up
CaCO3 precipitation
Exotic downhole
chemistries
Possible Solutions:Don’t allow it to build up
Acid washing
Mechanical pipe cleaning
Steam/water-jet cleaning
Limit Leachate Issues Through Proper Engineering & OM&M
SCS ENGINEERS
Limit
Generation
Summary
Leachate Issues Will Happen!
Can be mitigated through:
- Engineering Design
- Maintenance
- Operations
SCS ENGINEERS
Landfill Leachate Treatment• Aeration/Equalization Pond
• Aeration Tank
• Ultra Filtration
• Reverse Osmosis
• Discharge to River
• Background:•Constructed wetlands
•River
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SCS ENGINEERS
Landfill Leachate Treatment
• Two Ultra Filtration Units (semi-permeable membrane)
• Pore size range:• 0.1 micron to
0.003 micron
• Pressure: 30-150 psi
• Removes:• Colloidal particles
• Polymers
• Smallest TSS
• No TDS
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SCS ENGINEERS
Landfill Leachate Treatment
• Two Reverse Osmosis Units
• Pore size range:•0.001 micron to 0.0001 micron
• Pressure: up to 1,000 psi
• Removes:•Bacteria
•Viruses
• TDS
•95% of organic salts
•Minimal ammonia removal (gas)
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SCS ENGINEERS
Landfill Leachate Treatment
• Series of reverse osmosis cartridges in each of the five RO stages
• Each cartridge membrane is spiral wound
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SCS ENGINEERS
Landfill Leachate Treatment
• Each reverse osmosis cartridge - WW enters @ end
• Contaminated water flows thru multiple stages (“Concentrate”)
• Clean water exits the center tube (“Permeate”)
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SCS ENGINEERS
Wastewater passes through these processes:
• Aeration/EqualizationPond
• Aeration Tank
• Ultra Filtration
• Reverse Osmosis
• Discharges:• Permeate – Discharged
to River Tributary or CWL
• Concentrate –LF Recirculation
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Landfill Leachate Treatment
SCS ENGINEERS
Leachate Evaporator
• 15,000 GPD leachate disposal
• Leachate is heated by LFG•1,700 F combustion gas temperature
•180 F leachate temperature
•Water is driven off
• Only sludge remains•Concentrated slurry is dewatered
• Sludge is disposed of in thelandfill
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SCS ENGINEERS
Deep Injection Well Installation• Depth ranges: 3,500 to 12,500 feet
• Far below drinking water strata
• Within >10,000 ppm TDS formation
• Confining layer above injection
• Monitoring well also installed
• Heavily regulated
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SCS ENGINEERS
LF Leachate:
Limit
Generation
&
Control
Disposal
Summary
Leachate Issues Will Happen!
There are Many Engineering, Maintenance and Ops Solutions
Limit Leachate Generation First
If POTW is Currently Treating Your Leachate, Beware of Being Cutoff
Treatment Solutions are Available That Vary Widely in Application
SCS ENGINEERS
Thank You!
Questions and Comments
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Sam Cooke, PE
(608) 216-7382
scsengineers.com