Geosynthetics October/November 2021 - 16

Using bentonite-polymer composite GCLs to contain CCR leachates
10
10
-9
-10
Qin/Qout
10
-11
10
-12
(4a) K and Qin/Qout
1.5
2
0.5
1
(4b) pH and EC
50
100
150
Cumulative Inflow (mL)
FIGURES 4a and 4b Hydraulic conductivity and flow ratio (Qin/Qout) (4a) and pH ratio (pHout/
pHin) and EC ratio (ECout/ECin) (4b) as a function of cumulative inflow for hydraulic conductivity
test on GCL BPC6.3 permeated with CCR-VA2 leachate.
FIGURE 5 Hydraulic conductivity
versus ionic strength of the
CCR leachates. Zone enclosed
by dashed lines corresponds to
hydraulic conductivities of NaB
GCLs to CCR leachates.
10-12
10-11
10-10
10-9
10-8
10-7
10-6
10-5
BP4.0
BP5.8
BP6.3
BP8.6
BP8.9
BP9.0
BP9.7
NaB
NaB results from Chen et al. (2019)
10-3 101
102
Ionic Strength (mM)
16
Geosynthetics | October November 2021
103
Results
Hydraulic conductivity
Typical graphs of hydraulic conductivity,
Qin/Qout, pHout/pHin and ECout/ECin
versus cumulative inflow are shown in
Figures 4a and 4b, which show data from
the test on GCL BP6.3 permeated with
the CCR-VA2 leachate. The final hydraulic
conductivity was 4.2 × 10-12 m/s.
Hydraulic conductivity of the GCL gradually
decreased and then leveled out after
3.4 ounces (100 mL) of inflow. The ratio
200
50
Hydraulic Conductivity
100
0.01
0.1
1
10
100
150
Cumulative Inflow (mL)
Closed = pHout /pHin
Open = ECout /ECin
0.5
1
1.5
2
250
200
250
rolls following the method described in
Jo et al. (2001). Excess geotextile fibers
were carefully removed from the edge
of GCL specimens, and bentonite paste
prepared with the permeant liquid was
applied to the edge of specimens to prevent
bentonite loss that could potentially
induce sidewall leakage. The GCL specimens
were placed between two nonwoven
geotextiles (mass per area = 7.1
ounces per square yard [240 g/m2]) to
evenly distribute flow and to prevent
fouling with polymer eluted from the
GCL. The effective stress was set at 2.9
psi (20 kPa) and the average hydraulic
gradient was 190.
GCL specimens were hydrated with
CCR leachate for 48 hours prior to permeation.
Hydration was conducted in
the permeameters with the cell pressure
applied, the headwater applied and the
effluent valve closed. Permeation followed
immediately afterward and was
conducted until the hydraulic conductivity
was steady, the ratio of incremental
outflow to inflow (Qout/Qin) was within
1.00 ± 0.25, and the pH and EC of the
effluent were within 10% of those of the
influent. Duplicate tests were conducted
to ensure the results were reproducible.
When relatively high hydraulic conductivities
(10-8 m/s) were obtained, the
influent was spiked with Rhodamine WT
dye to stain flow paths through the GCL.
Q /Q
in
out
EC
out
/EC
in
pH
out
/pH
Hydraulic Conductivity (m/s)
in
Hydraulic Conductivity (m/s)

Geosynthetics October/November 2021

Table of Contents for the Digital Edition of Geosynthetics October/November 2021

Geosynthetics October/November 2021 - Cover1
Geosynthetics October/November 2021 - Cover2
Geosynthetics October/November 2021 - 1
Geosynthetics October/November 2021 - 2
Geosynthetics October/November 2021 - 3
Geosynthetics October/November 2021 - 4
Geosynthetics October/November 2021 - 5
Geosynthetics October/November 2021 - 6
Geosynthetics October/November 2021 - 7
Geosynthetics October/November 2021 - 8
Geosynthetics October/November 2021 - 9
Geosynthetics October/November 2021 - 10
Geosynthetics October/November 2021 - 11
Geosynthetics October/November 2021 - 12
Geosynthetics October/November 2021 - 13
Geosynthetics October/November 2021 - 14
Geosynthetics October/November 2021 - 15
Geosynthetics October/November 2021 - 16
Geosynthetics October/November 2021 - 17
Geosynthetics October/November 2021 - 18
Geosynthetics October/November 2021 - 19
Geosynthetics October/November 2021 - 20
Geosynthetics October/November 2021 - 21
Geosynthetics October/November 2021 - 22
Geosynthetics October/November 2021 - 23
Geosynthetics October/November 2021 - 24
Geosynthetics October/November 2021 - 25
Geosynthetics October/November 2021 - 26
Geosynthetics October/November 2021 - 27
Geosynthetics October/November 2021 - 28
Geosynthetics October/November 2021 - 29
Geosynthetics October/November 2021 - 30
Geosynthetics October/November 2021 - 31
Geosynthetics October/November 2021 - 32
Geosynthetics October/November 2021 - 33
Geosynthetics October/November 2021 - 34
Geosynthetics October/November 2021 - 35
Geosynthetics October/November 2021 - 36
Geosynthetics October/November 2021 - 37
Geosynthetics October/November 2021 - 38
Geosynthetics October/November 2021 - 39
Geosynthetics October/November 2021 - 40
Geosynthetics October/November 2021 - 41
Geosynthetics October/November 2021 - 42
Geosynthetics October/November 2021 - 43
Geosynthetics October/November 2021 - 44
Geosynthetics October/November 2021 - Cover3
Geosynthetics October/November 2021 - Cover4
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-december-2021-january-2022
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-october-november-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-august-september-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-june-july-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-april-may-2021
https://www.nxtbook.com/ifai/geosynthetics/geosynthetics-february-march-2021
https://www.nxtbook.com/ifai/geosynthetics/1220GS
https://www.nxtbook.com/ifai/geosynthetics/1020GS
https://www.nxtbook.com/ifai/geosynthetics/0820GS
https://www.nxtbook.com/ifai/geosynthetics/0620GS
https://www.nxtbook.com/ifai/geosynthetics/0420GS
https://www.nxtbook.com/ifai/geosynthetics/0220GS
https://www.nxtbook.com/ifai/geosynthetics/1219GS
https://www.nxtbook.com/ifai/geosynthetics/1019GS
https://www.nxtbook.com/ifai/geosynthetics/0819GS
https://www.nxtbook.com/ifai/geosynthetics/0619GS
https://www.nxtbook.com/ifai/geosynthetics/0419GS
https://www.nxtbook.com/ifai/geosynthetics/0219GS
https://www.nxtbook.com/ifai/geosynthetics/1218GS
https://www.nxtbook.com/ifai/geosynthetics/1018GS
https://www.nxtbook.com/ifai/geosynthetics/0818GS
https://www.nxtbook.com/ifai/geosynthetics/0618GS
https://www.nxtbook.com/ifai/geosynthetics/0418GS
https://www.nxtbook.com/ifai/geosynthetics/0218GS
https://www.nxtbookmedia.com