Landfill Leachate:Limit Generation,Control Disposal

Sam Cooke, PEApril 20, 2018

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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 Leachate Issues – Temporary

Rain Cover

SCS ENGINEERS

Limit Leachate Issues – Temporary Rain Cover

SCS ENGINEERS

Leachate Issues – It rained a lot over

the weekend!

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• Aeration pond with multiple aerators

• Equalization

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SCS ENGINEERS

Landfill Leachate Treatment• Aeration pond

with multiple aerators

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SCS ENGINEERS

Landfill Leachate Treatment• Aeration tank with coarse bubble aerators

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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

Deep Injection Well Installation• Injection water treatment for solids removal

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SCS ENGINEERS

Deep Injection Well Installation• Injection water treatment for solids removal

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SCS ENGINEERS

Deep Injection Well Operation

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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

scooke@scsengineers.com

scsengineers.com