Download - Managing Leachate Seeps Below Final Cover Managing... · Below Final Cover Ali Khatami, Ph.D., P.E. SCS Engineers SCS ENGINEERS Leachate Seeps • Many reasons for leachate seeps

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S C S E N G I N E E R S

Managing Leachate SeepsBelow Final Cover

Ali Khatami, Ph.D., P.E.SCS Engineers


Leachate Seeps

• Many reasons for leachate seeps

• Operator manages leachate seeps while slope unclosed

• Various means and methods for management of leachate seeps

• Full closure and leachate seeps

• Partial closure and leachate seep

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Leachate Seeps Below Geomembrane


Leachate Toe Drain System

(LTDS)

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Location of LTDS


Leachate at Toe of Slope

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Leachate Pool at Perimeter Berm


Removing Leachate by Vac Truck

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Vac Truck


Exposing Anchor Trench

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Excavating Overfill


Excavating Overfill

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Grading Slope


Graded Slope

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Graded Slope


Graded Slope

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LTDS Geocomposite Deployment


LTDS Geocomposite

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LTDS Geocomposite


Anchor Trench Excavation

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Anchor Trench for LTDS Geocomposite


Bottom of LTDS Geocomposite

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Extension of LTDS Geocomposite


Extended LTDS Geocomposite on Slope

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Anchor at High End of Seep


Connection Points to Cleanouts

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Connection Point to Sump Riser


Connection Point to Sump Riser

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Deployment of LTDS Geotextile


LTDS Pipe Placement

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Vertical Pipe


LTDS Pipe Placement

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Vertical Pipe


LTDS Pipe Connection to Cleanout Pipe

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Connection of LTDS Pipe to Sump Riser



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LTDS Gravel Placement

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Forming Gravel around LTDS Pipe



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Gravel at End of LTDS Pipe

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Closing LTDS Burrito


Placement of Soil Above LTDS Burrito

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Soil Above LTDS Burrito


LTDS at Completion

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LTDS Pipe at Cell Construction Time


LTDS Drain Pipes

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LTDS Drain Pipe into Leachate Sump



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Sump and LTDS Drain Pipe

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LTDS Drain Pipe at Leachate Sump


LTDS Drain Pipe into Leachate Corridor

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Closed Burrito


Cover Geomembrane Welded toBottom Geomembrane

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Cover Geomembrane Welded toBottom Geomembrane


Granular Bentonite Over Extrusion Weld

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Granular Bentonite Over Extrusion Weld


GCL Strip Over Granular Bentonite

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Cover Soil Placement

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Slope Final Condition


Slope Final Condition

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Benefits of LTDS

• Collects and removes leachate below final cover geomembrane

• Eliminates ponding of leachate below final cover geomembrane at toe of slope

• Provides gas collection at toe of slope

• Connects to leachate collection sump, sump riser, or cleanouts

• Addresses aggressive leachate seeps on slope


Construction Recommendations

• Construct LTDS and drain pipes at time of cell development

• Set LTDS pipe invert below top of berm

• Leave no sand between LTDS geocomposite and LTDS geotextile

• Construct vertical pipes for future connection to gas system

• Do not use sacrificial geomembrane over LTDS, use geotextile to allow infiltration