Clay lining to protect groundwater from leachate
Clay lining to protect groundwater from leachate
(OP)
What kind of clay work the best to protect the groundwater from leachate? I know that we need a hydraulic conductivity less than 10^-9 to do that....but I read somewhere that bentonite and kaolinite don't have a low hydraulic conductivity like what we need to do the lining. I need explanation and help. Is it depends on what kind of permeability method do we use? like falling head or constant head? Or like how thick should the bentonite and kaolinite we should use?





RE: Clay lining to protect groundwater from leachate
1) gravel base layer
2) sodium bentonite GCL liner, 1 x 10 -6 cm/s
3) 60 mil HDPE geomembrane secondary liner
4) geonet collection layer
5) 60 mil HDPE geomembrane primary liner
need leak detection and collection system in layer 4
RE: Clay lining to protect groundwater from leachate
Typically from top to bottom is some type of dual liner system with a leak detection system:
top
1) 1-2 feet Drainage layer (Note: can be replaced by a geonet) (this is where the leachate pipes are located)
2) 60 mil HDPE (plastic liner)
3) 2 feet of clay with a maximum hydraulic conductivity of 1 x 10^-6 cm/s (Note: this may be replaced by a GCL liner if clay is not available)
4) 2 feet of drainage layer (Note: can be replaced by a geonet) (This is where you have a leak detection system)
5) 60 mil HDPE
6) 2 feet of clay with a maximum hydraulic conductivity of 1 x 10^-6 cm/s (Note: this may be replaced by a GCL liner if clay is not available)
7) Compacted soil
Bottom
The purpose of the dual liner system is that if the top liner system (Items 2 & 3) leak, there's a secondary system (5 & 6) to minimize the potential of releases from the landfill.
RE: Clay lining to protect groundwater from leachate
placing thick layers of clay is very costly unless you have a stockpile of clay within a close haul distance from your project, so GCL is usually far more economical. clay or low permeabilty materials which contain clay can be used for top cover and drainage layer over the landfill to reduce the infiltration and limit the amount of leachate produced.
RE: Clay lining to protect groundwater from leachate
f-d
p.s., I'm guessing your permeability in the OP is meters/second, which would relate to 10-7 cm/sec. That's very typical in the US. An earlier post suggested 10-6 cm/sec. Local environmental agency may have requirements of one value or the other.
ípapß gordo ainÆt no madre flaca!