Abstract

When the coal combustion products are used in soil stabilization and embankments construction, leaching of trace elements into groundwater can be a concern. This paper presents a modeling study to evaluate the impacts of leaching on groundwater from coal combustion products in roadway embankment constructions. A computer program, WiscLEACH, based on three analytical solutions for the advection-dispersion-reaction process in the subsurface was used. The soil stabilization module and embankment module were developed in the program. Predictions made with the analytical method were compared to field data from a fly ash embankment. The predicted concentrations with WiscLEACH are in reasonable agreement with the field data. Dilution factor at the point of compliance was defined and used as quantitative parameter to compare the different scenarios. Parametric studies indicate that the lowest dilution factor exponentially decrease as the thickness of the coal combustion products layer and the seepage velocity in the vadose zone increase. Correlations among the dilution factor at the point of compliance and the construction geometry and hydrogeological condition were also developed.

Issue Section:
Research Papers
Keywords:
coal combustion products, groundwater, leaching, trace elements, embankment

References

1.
ACCA
,
ACAA Coal Combustion Product Production and Use Survey
,
American Coal Ash Association
,
Aurora, CO
,
2009
.
2.
Bin-Shafique
,
S.
,
Edil
,
T. B.
,
Benson
,
C. H.
, and
Senol
,
A.
, “
Incorporating a Fly-Ash Stabilised Layer into Pavement Design
,”
Proc. ICE -Geotech. Eng.
, Vol.
157
, No.
4
,
2004
, pp.
239
–
249
.
Google Scholar
Crossref
Search ADS
 
3.
Edil
,
T. B.
,
Acosta
,
H. A.
, and
Benson
,
C. H.
, “
Stabilizing Soft Fine-Grained Soils with Fly Ash
,”
J. Mater. Civ. Eng.
, Vol.
18
,
2006
, pp.
283
–
294
 https://doi.org/10.1061/(ASCE)0899-1561(2006)18:2(283).
Google Scholar
Crossref
Search ADS
 
4.
Kim
,
B.
,
Prezzi
,
M.
, and
Salgado
,
R.
, “
Geotechnical Properties of Fly and Bottom Ash Mixtures for Use in Highway Embankments
,”
J. Geotech. Geoenviron. Eng.
, Vol.
131
, No.
7
,
2005
, pp.
914
–
924
. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:7(914)
Google Scholar
Crossref
Search ADS
 
5.
Li
,
L.
,
Benson
,
C. H.
,
Edil
,
T. B.
, and
Hatipoglu
,
B.
, “
Sustainable Construction Case History: Fly Ash Stabilization of Recycled Asphalt Pavement Material
,”
Geotech. Geolog. Eng.
, Vol.
26
,
2008
, pp.
177
–
187
. https://doi.org/10.1007/s10706-007-9155-2
Google Scholar
Crossref
Search ADS
 
6.
Li
,
L.
,
Benson
,
C. H.
, and
Edil
,
T. B.
, “
Mechanical Performance of Pavement Geomaterials Stabilized with Fly Ash in Field Applications
,”
Coal Combust. Gasif. Products
, Vol.
1
,
2009
, pp.
43
–
49
. https://doi.org/10.4177/CCGP-D-09-00018.1
7.
Apul
,
D.
,
Gardner
,
K.
,
Eighmy
,
T.
,
Linder
,
E.
,
Frizzell
,
T.
, and
Roberson
 
R.
, “
Probabilistic Modeling of One-Dimensional Water Movement and Leaching from Highway Embankments Containing Secondary Materials
,”
Environ. Eng. Sci.
, Vol.
22
, No.
2
,
2005
, pp.
156
–
169
. https://doi.org/10.1089/ees.2005.22.156
Google Scholar
Crossref
Search ADS
 
8.
Mudd
,
G. M.
,
Weaver
 
T. R.
, and
Kodikara
,
J.
, “
Environmental Geochemistry of Leachate from Leached Brown Coal Ash
,”
J. Environ. Eng.
, Vol.
130
, No.
12
,
2004
, pp.
1514
–
1526
. https://doi.org/10.1061/(ASCE)0733-9372(2004)130:12(1514)
Google Scholar
Crossref
Search ADS
 
9.
Sauer
,
J. J.
,
Benson
 
C. H.
, and
Edil
 
T. B.
, “
Metals Leaching from Highway Test Sections Constructed with Industrial Byproducts
,” Geo Engineering Report No. 05–21,
Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison
, Madison, WI,
2005
.
10.
Bin-Shafique
,
S.
,
Benson
,
C. H.
,
Edil
 
T. B.
, and
Hwang
 
K.
, “
Leachate Concentrations from Water Leach and Column Leach Tests on Fly-Ash Stabilized Soils
,”
Environ. Eng. Sci.
, Vol.
23
, No.
1
,
2006
, pp.
53
–
67
. https://doi.org/10.1089/ees.2006.23.53
Google Scholar
Crossref
Search ADS
 
11.
Edil
,
T. B.
,
Benson
,
C. H.
,
Bin-Shafique
,
M. S.
,
Tanyu
,
B. F.
,
Kim
,
W -H.
, and
Senol
,
A.
, “
Field Evaluation of Construction Alternatives for Roadways over Soft Subgrade
,” Transportation Research Record. 1786, Transportation Research Board, Washington, D.C.,
2002
, pp.
36
–
48
.
12.
Li
,
L.
,
Benson
,
C. H.
,
Edil
,
T. B.
, and
Hatipoglu
,
B.
, “
Groundwater Impacts from Coal Ash in Highways
,”
Waste Resour. Manage.
, Vol.
159
,
2006
, pp.
151
–
163
. https://doi.org/10.1680/warm.2006.159.4.151
13.
Friend
,
M.
,
Bloom
,
P.
,
Halbach
,
T.
,
Grosenheider
 
K.
, and
Johnson
 
M.
, “
Screening Tool for Using Waste Materials in Paving Projects (STUWMPP)
,” Report No. MN=RC–2005–03, Office of Research Services, MN Dept. of Transportation, MN,
2004
.
14.
Hesse
,
T. E.
,
Quigley
 
M. M.
, and
Huber
 
W. C.
, “
User’s Guide: IMPACT—A Software Program for Assessing the Environmental Impact of Road Construction and Repair Materials on Surface and Ground Water
,”
NCHRP 25–09: Environmental Impact of Construction and Repair Materials on Surface and Ground Waters
,
Oregon State University
,
Corvallis, OR
,
2000
.
15.
RTI and HydroGeoLogic
,
Draft IWEM Beta Version 2.0 with Roadway Module Technical Documentation and User’s Guide
,
2008
.
16.
Leij
,
F. J.
,
Priesack
,
E.
, and
Schaap
,
M. G.
, “
Solute Transport Modeled with Green’s Functions with Application to Persistent Solute Sources
,”
J. Contam. Hydrol.
, Vol.
41
, No.
1–2
,
2000
, pp.
155
–
173
. https://doi.org/10.1016/S0169-7722(99)00062-5
17.
Leij
,
F. J.
,
Skaggs
,
T. H.
, and
van Genuchten
,
M. T.
, “
Analytical Solutions for Solute Transport in Three-Dimensional Semi-Infinite Porous Media
,”
Water Resour. Res.
, Vol.
27
, No.
10
,
1991
, pp.
2719
–
2733
. https://doi.org/10.1029/91WR01912
Google Scholar
Crossref
Search ADS
 
18.
Gardner
,
K.
, “
National Green Highway Activities and Resources to Support Recycling and Reuse
,” Resource Conservation Challenge (RCC) 2009 Workshop, Hyatt Regency Crystal City, D.C., March 25–27,
2009
.
19.
Erbe
,
M. W.
,
Keating
,
R. W.
, and
Hodges
,
W. K.
, “
Evaluation of Water Quality Conditions Associated with the Use of Coal Combustion Products for Highway Embankments
,”
1999 International Ash Utilization Symposium, Center for Applied Energy Research
,
Univ. of Kentucky
, Paper No. 31,
1999
.
20.
Freeze
,
R. A.
, and
Cherry
,
J. A.
,
Groundwater
,
Prentice–Hall
,
Englewood Cliffs, NJ
,
1979
.
21.
Lerman
,
A.
,
Geochemical Processes in Water and Sediment Environments
,
Wiley
,
New York
,
1979
.
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