ETTL Engineers
& Consultants Inc.

 

CQC & CQA Services for Landfill Liners
and Final Cover Systems (Caps)

Highly experienced ETTL personnel are available to carry out CQC and CQA services before and during placement of composite liners when landfill cells are being constructed. As the sketch below indicates, the composite liners comprising the bottom liners and the final cover systems (or caps) of cells make use of geomembrane liners (GL) and either compacted clay liners (CCL) or geosynthetic clay liners (GCL). Photos of such liners being installed are shown below the sketch, accompanied by brief summaries of the CQC and CQA services ETTL provides.

THE FOUR LAYERS OF A TYPICAL LANDFILL CELL

FINAL COVER SYSTEM (Composite Liner)

< Top Soil (Vegetative Layer)
< GL
< CCL or GCL

TRASH

 

LEACHATE COLLECTION SYSTEM

< Geocomposites or Aggregates plus Piping

BOTTOM LINER (Composite Liner)

< GL
< CCL or GCL

GL = Geomembrane Liner --- CCL = Compacted Clay Liner

--- GCL = Geosynthetic Clay Liner


ETTL CQC and CQA Services for the Various Liner Types

Compacted Clay Liners (CCL)
ETTL monitors the compactive efforts of the contractor by carrying out moisture density testing in the field after the contractor places each lift of clay. Typical clay liners are 1' to 3' thick, depending on permit requirements. In addition, we take undisturbed samples of the clay liner, bring them to ETTL's geotechnical laboratories and carry out falling head permeability testing (which can have a turnaround time as low as 24 hours). All results are compiled in a Soil Liner Evaluation Report (SLER), reviewed and certified by an ETTL professional engineer.

Geosynthetic Clay Liners (GCL)* (See asterisked note below)
ETTL provides full-time inspection of installation of GCLs, which are comprised of sodium bentonite, bound by a woven and non-woven geotextile or adhered to a geomembrane. We measure and number panels as they are placed, making records, generating as-built drawings, which become part of a Geosynthetic Clay Liner Evaluation Report (GCLER), which in turn becomes part of the over-all Certification Report for the composite liner - either a Bottom Liner or a Final Cover System (the cap of the cell).


Above: An ETTL field technician records data as geomembrane liner panels are welded together.

Geomembrane Liners (GL)* (See asterisked note below)
ETTL also provides full-time inspection of installation of GLs, monitoring panel placement: keeping track of panel thickness and generating as-built drawings. As panels are installed and welded together, ETTL monitors seam lengths, type of seam, records dates, times, and name(s) of welding equipment operator(s), and keeps track of (monitors) non-destructive testing of the seams by the installer. Finally, ETTL selects where to destructively test seams. Three samples are cut out. One sample is tested by the installer for shear strength and peel; another sample is independently tested for the same properties, and the third sample is archived. All this information is documented in a Certification Report (Geomembrane Liner Evaluation Report: GLER).

* Before GCLs or GLs are placed in a cell, ETTL visits the GCL or GL manufacturer, takes component samples, and verifies that they meet all pertinent specifications.

 

NOTE: The laboratory tests normally carried out during landfill liner installation projects can be obtained directly from ETTL by harnessing ETTL's Contract Soil Laboratory Services. For more information, click kere.

For additional infomation on ETTL's CQC & CQA Services for Landfill Liners, contact Brandon Quinn

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