Agricultural use of fly ash:
Expected benefits and
consequences
Christos D. Tsadilas
Hellenic Agricultural Organization “DEMETER”
Institute of Soil Mapping and Classification,
1 Theophrastos street, 413 35 Larissa, Greece,
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
PRESENTATION’S HIGHLIGHTS
• Properties, elemental composition, and organic pollutants in
Coal Fly Ash (CFA)
• Opportunities and challenges in the use of CFA for soil
improvements
• The influence of CFA on plant growth and pollutants
availability
• The recent advances made in single and multi-component
utilization of CFA
• CFA use for remediation of contaminated soils and
wastewaters
• Impact of CFA amendment on soil carbon
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
WHAT IS COAL FLY ASH
• Coal Combustion Products (Heidrich et al., 2013)
– Bottom ash
– Boiler slag
– Fluidized-bed combustion ash
– Flue gas desulfurization material
– Fly ash: the finer ash produced in coal-fired power
station, collected by using electrostatic
precipitators. It comprises about 85% of the total
ash produced. It will be abbreviated as CFA.
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
CLASSIFICATION OF COAL FLY ASHES
In terms of their potential to neutralize acidity, fly ashes
can be broadly grouped into two classes:
Class C (lignite and sub-bituminous): high in CaO
(>20%), alkali, and crystalline compounds, but low in
silica.
Class F (bituminous and anthracite): modest
concentrations of CaO (<20%) and may contain lower
proportions of crystalline components, but also have
pozzolanic properties.
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
PROPERTIES OF COAL FLY ASH
Acidity, alkalinity
(Shaheen et al., JEM in press)
Property
pH
Electrical conductivity,
CFA
4.5 – 13.25
1.10 – 19.06 dS/m
(Manoharan et al., 2010)
PROPERTIES OF COAL FLY ASH
Mineralogical properties
(Alonso and Wesche, 1991)
Property
Glassy particles, %
Crystal particles
Unburned coal
Magnetite, %
Hematite, %
Quartz, %
Mullite, %
Free CaO, %
CFA
50-90
Very small amount
Up to 16%
0.8-6.5
1.1-2.7
2.2-8.5
6.5-9.0
Up to 3.5
PROPERTIES OF COAL FLY ASH
Physical properties
(Shaheen et al., JEM in press; Basu et al., 2009)
Property
Texture
CFA
SiL
Specific surface,
Blaine method, cm2/g
2730-5290
Specific gravity, g/cm3
1.0-1.8
Water holding capacity, %
35-40
Porosity, %
50-60
Unburned coal content, %
0.5-12
Color
Water-white to to yellow-orange to deep red or
brown to opaque depending mainly on the Fe2O3
and carbon contents
PROPERTIES OF COAL FLY ASH
Elemental composition of CFA and soils - Major elements
(Shaheen et al., JEM in press; Yunusa et al., 2012)
Element, %
CFA
Soils
N
0.01-0.12
0.01-1.0
Al
Ca
0.047-31.2
0.0029–8.64
4-30
0.7-50
Fe
K
0.00032-6.8
0.00021-2.45
0.7-55
0.04-3
Mg
P
S
0.0017-7.6
0.00024-1.08
0.0013-2.0
0.06-0.6
0.005-0.2
0.01-0.20
PROPERTIES OF COAL FLY ASH
Elemental composition of CFA and soils - Trace elements
(Shaheen et al., JEM in press)
Element, mg/kg
CFA
Soils
As
b.d.l*.-6300
0.1-40
B
0.40-618
2-100
Cd
0.03-130
0.01-7.
Co
7-520
1-40
Cr
10-1000
5-3000
Cu
0.002-2800
2-100
Hg
b.d.l.-1.0
-
Mn
0.006-3000
100-4000
Mo
3-160
0.2-5.0
Ni
6.3-4300
10-1000
Pb
3.1-5000
2-100
V
20-182
50-1000
Se
0.2-134
10-25
Zn
10-3500
10-300
*below detection limit
PROPERTIES OF COAL FLY ASH
Organic pollutants (Sahu et. al, 2009-Microchemical Journal)
PAHs-Polycyclic aromatic
hydrocarbons
(Sahu
et al.,ng/g
2009, Microchemical
Mean
content,
PCBs-PolychlorinatedJournal)
Mean content, ng/g
biphenyls
Average concentrations of PAHs and PCBs in CFA
Napthalene
31.09
PCB-18
ND
Acenapthalene
14.85
PCB-28
1.42
Fluorene
162.71
PCB-52
1.17
Phenantherene
8.42
PCB-77
62.53
Anthracene
0.23
PCB-101
3.02
Fluoranthene
16.48
PCB-138
2.51
Pyrene
5.35
PCB-153
2.01
Benzo(a)anthracene
14.35
PCB-180
2.18
Perylene
6.68
PCB-194
0.29
Benzo(k)Fluoranthene
5.23
PCB-44
ND
Benzo(a)pyrene
9.02
PCB126
ND
Total
354.68
Total
75.13
Fly ash utilization options
(Malik & Thapliyal, 2009)
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Advantages and constraints of Land Application of CFA
(Malik & Thapliyal, 2009)
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
• pH correction
– Increase from 4.7 to 7.7 or 5.6 to 6.7 – 7.5 (Matsi
and Keramidas, 1999; Shaheen and Tsadilas, 2010)
with alkaline CFA (pH 8.5-8.9 or 12.2)
– Decrease with acidic CFA (Neuapane and
Donahoe, 2013; Elseewi and Page, 1984)
• Electrical conductivity
– Increase (Tsadilas et al., 2002)
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
• Texture
– Changed from Sand and Clayey to Loamy with
addition 70 ton/ha (Fail and Wochok, 1977)
• Bulk density
– Decrease (Mittra et al., 2003)
• Water holding capacity
– Increased by addition at rate 8% (Chnag et al., 1977)
• Aeration, percolation, and retention
– Improved (Malik and Thapliyal, 2009)
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Plant growth and yield (Shaheen et al., JEMA, in press)
Plant
CFA rate
Yield of control
Yield of CFA amended
Pot experiments
Rice
0-8%(w/w)
25,3 g/pot
27.7 g/pot
Wheat
0-8%
3.77 g/pot
3.78 g/pot
Tomato
0-100% (v/v)
4,5 g/pot
9.5 g/pot
Faba bean
0-30%
3 g/pot
4.2 g/pot
Rye grass
0.5-5% (w/w)
15.8 g/pot
28.5 g/pot
Mentha
piperitia
0-100%
6.7
10.5
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Rice
a.g.b.*
1.5
1.7
80 t/ha
Wheat
a.g.b.
2.8
2.8
80 t/ha
Wheat
grains
1.9
2.0
100 t/ha
Maize
grains
1.5
1.6
100 t/ha
Eggplant
fruits
2.0
2.1
100 t/ha
Rice
a.g.b.
0.21
0.19
80 t/ha
Wheat
a.g.b.
0.27
0.27
80 t/ha
Wheat
grains
0.23
0.27
100 t/ha
Macronutrients , mg/kg
N
P
*:above ground biomass
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Maize
grains
0.16
0.19
100 t/ha
Eggplant
grains
0.14
0.17
100 t/ha
Rice
a.g.b.
2.5
2.6
80 t/ha
Wheat
a.g.b.
5.1
5.1
80 t/ha
Wheat
grains
1.6
1.6
100 t/ha
Maize
grains
1.5
1.6
100 t/ha
Eggplant
fruits
2.0
2.1
100 t/ha
Wheat
a.g.b.
0.9
1.1
Macronutrients , mg/kg
P
K
*:above ground biomass International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Rice
a.g.b.
0.23
0.25
80 t/ha
Wheat
a.g.b.
0.01
0.01
80 t/ha
Wheat
grains
0.15
0.18
100 t/ha
Maize
grains
0.14
0.17
100 t/ha
Eggplant
Fruits
0.39
0.43
100 t/ha
Wheat
a.g.b.
0.18
0.23
5.5 t/ha
Macronutrients , mg/kg
Ca
*:above ground biomass
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Rice
a.g.b.
0.18
0.19
80 t/ha
Wheat
a.g.b.
0.20
0.21
80 t/ha
Wheat
grains
0.10
0.13
100 t/ha
Maize
grains
0.08
0.11
100 t/ha
Eggplant
Fruits
0.19
0.23
100 t/ha
Wheat
a.g.b.
0.16
0.30
5.5 t/ha
Macronutrients , mg/kg
Mg
*:above ground biomass
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Rice
a.g.b.
0.18
0.19
80 t/ha
Wheat
a.g.b.
0.11
0.11
80 t/ha
Wheat
grains
0.25
0.25
100 t/ha
Maize
grains
0.08
0.11
100 t/ha
Eggplant
Fruits
0.12
0.19
100 t/ha
Macronutrients , mg/kg
S
*:above ground biomass
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Turf grass
whole plant
10.8
13.7
560 t/ha
Ryegrass
a.g.b.
10-60
16-90
100 t/ha
Wheat
a.g.b.
9.5
11.0
5.5 t/ha
Rice
a.g.b.
7.9
8.2
80 t/ha
Wheat
a.g.b.
2.2
2.6
80 t/ha
Maize
grains
2.1
2.2
100 t/ha
Eggplant
fruits
4.0
4.6
100 t/ha
Mustard
seeds
6.3
2.6
100 t/ha
Micronutrients , mg/kg
B
Cu
*:above ground biomass International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Rice
a.g.b
26.3
23.3
80 t/ha
Wheat
a.g.b.
23.4
23.0
80 t/ha
Wheat
Grains
1.5
1.7
100 t/ha
Maize
Grains
12.3
13.0
100 t/ha
Eggplant
Fruits
11.7
12.3
100 t/ha
Chicory
a.g.b
30.1
10.5
60 t/ha
Mustard
seeds
18.5
13.4
100 t/ha
Turfgrass
whole plant
59.0
44.0
100 t/ha
Micronutrients , mg/kg
Zn
*:above ground biomass International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Rice
a.g.b
25.6
26.1
80 t/ha
Wheat
a.g.b.
21.8
19.6
80 t/ha
Wheat
Grains
13.8
14.3
100 t/ha
Maize
Grains
11.5
12.2
100 t/ha
Eggplant
Fruits
15.8
16.5
100 t/ha
Mustard
seeds
15.5
10.5
100 t/ha
Turfgrass
whole plant
264
100
280 t/ha
Micronutrients , mg/kg
Mn
*:above ground biomass
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Rice
a.g.b
176
197
80 t/ha
Wheat
a.g.b.
138
127
80 t/ha
Wheat
Grains
34
38
100 t/ha
Maize
Grains
28
29
100 t/ha
Eggplant
Fruits
11
12
100 t/ha
Mustard
seeds
186
95
100 t/ha
Micronutrients , mg/kg
Fe
*:above ground biomass
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
Plant tissue
Control
CFA treated soil
CFA rate
Wheat
Grains
0.36
0.39
100 t/ha
Maize
Grains
0.45
0.50
100 t/ha
Eggplant
Fruits
0.36
0.41
100 t/ha
Turfgrass
Whole plant
4.5
18
280 t/ha
Micronutrients , mg/kg
Mo
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Effects of Land Application of CFA
Nutrient uptake (Shaheen et al., JEMA, in press)
Element
Plant
CFA treated soil
CFA rate
Potentially toxic Elements , mg/kg
Cd
Chicory, rice, mustard
No significant influence
200 t/ha
Pb
Wheat, maize, eggplant,
mustard
No significant influence
100 t/ha
Wheat, maize, eggplant,
chicory, rice
No significant influence
Mustard
Significant increase from 8.6 to
106.8 in seeds
100 t/ha
Wheat, maize, eggplant
No significant influence
100 t/ha
200 t/ha
Ni
Se, Cr
Results of some case studies in Greece
China – Greece bilateral project
“Agro-Environmental effects of the recycling of municipal sewage sludge and
coal fly ash”
Pot experiment
• Experimental Design: Randomized complete blocks
• Replications: 4
• Treatments
• C: control, soil alone
• IF: soil with inorganic fertilizers
• T1: soil plus 30 g fly ash/pot
• T2: soil plus 90 g fly ash/pot
• SS1: soil plus 2.63 g Sewage sludge/pot
• SS2: soil plus 5.25 g Sewage sludge/pot
• SS3: soil plus 10.5 g Sewage sludge/pot
Results of some case studies in Greece
China – Greece bilateral project
“Agro-Environmental effects of the recycling of municipal sewage sludge and
coal fly ash”
Adsorption experiment
Adsorption experiment was conducted in samples obtained at the end of the incubation
which were air-dried, ground and passed through a 2-mm sieve. Adsorption isotherms of Cd,
Cu, Pb & Zn were obtained by weighing 3 g of soil into acid-washed polyethylene bottles
prior to addition of 30 ml of 0.01 M CaCl2 solution containing different concentrations from
the studied elements as cadmium chloride.
Results of some case studies in Greece
China – Greece bilateral project
Pot experiment - Results
Treatm
Biomass,
g/pot
pH
HwsB,
mg/kg
EC,
mmhos/cm
Cu,
mg/kg
Pb,
mg/kg
Ni,
mg/kg
Zn,
mg/kg
C
4.65ab
5.02b
0.45b
0.082a
35a
4.16a
49a
43a
IF
7.01c
4.81a
0.17a
0.109b
75c
7.87c
105cd
90c
T1
4.13a
6.62e
0.84cd
0.163b
64b
6.93bc
91b
75b
T2
4.79ab
7.48f
1.38e
0.63d
75c
7.33bc
110cd
103c
SS1
5.90abc
6.54de
0.58b
0.204b
74c
7.31bc
106c
98c
SS2
6.71bc
6.39c
0.69bc
0.25c
77c
6.94bc
104c
99c
SS3
6.22bc
6.43cd
0.96c
0.221bc
79c
6.62b
118d
96c
a
4500
4000
3500
3000
b
2500
2000
b
b
1500
1000
b
b
b
500
0
Control
FA1
FA2
FA1SS1 FA1SS2
SS1
SS2
Zn_Distribution coefficient (L/kg)
Cu_Distribution coefficient (L/kg)
China – Greece bilateral project
Pot experiment - Results
350
a
300
250
200
150
ab
100
50
b
b
ab
Control
FA1
FA2
250
200
ab
b
100
c
c
c
50
Pb_Distribution coefficient (L/kg)
Cd_Distribution coefficient (L/kg)
300
ab
FA1SS1
FA1SS2
SS1
SS2
Treatments
a
150
b
0
Treatments
350
b
3500
a
3000
ab
2500
b
b
2000
1500
c
c
c
SS1
SS2
1000
500
0
0
Control
Control
FA1
FA2
FA1SS1
FA1SS2
SS1
FA1
FA2
FA1SS1
FA1SS2
SS2
Treatments
Treatments
Distribution coefficient (Kd) indicates the capability of a soil to retain a solute and consequently its distribution between
solid and liquid phase.
Results of some case studies in Greece
China – Greece bilateral project
Field experiment
Treatments
A: No amendments, no fertilizers
B: Application of inorganic Fertilizers
C: Application of 22.5 ton/ha CFA
D: Application of 67.5 ton/ha CFA
E: Application of 22.5 ton/ha CFA plus 6.3 ton/ha MSS
F: Application of 22.5 ton/ha CFA plus 22.5 ton/ha MS
Results of some case studies in Greece
China – Greece bilateral project
Field experiment - Results
Treatm
Total biomass, ton/ha
Grain yield, ton/ha
A, No amendments, no
fertilizers
5.09 a
3.09ab
B, Application of inorganic
Fertilizers
8.38bc
3.21ab
C, Application of 22.5 ton/ha
CFA
8.67bc
3.51abc
D, Application of 67.5 ton/ha
CFA
9.14cd
3.76bc
E, Application of 22.5 ton/ha
CFA plus 6.3 ton/ha MSS
7.54bc
3.97c
F, Application of 22.5 ton/ha
CFA plus 22.5 ton/ha MS
9.97d
4.14c
Results of some case studies in Greece
China – Greece bilateral project
Field experiment - Results
Treatm
A, no
Plant N, %
Plant P,
mg/kg
Plant K,
mg/kg
Plant Ca,
mg/kg
Plant Mg,
mg/kg
0.90a
0.12a
0.50ab
1.11ab
0.51a
1.73b
0.34b
0.47a
0.78a
0.60a
1.97b
0.36b
0.53b
1.25ab
0.66a
1.60b
0.31b
0.72c
1.77b
0.58a
1.67b
0.32b
0.71c
0.69a
0.64a
1.57b
0.34b
0.69c
0.67a
0.90b
amendments,
no fertilizers
B, inorganic
Fertilizers
C, 22.5 ton/ha
CFA
D, 67.5 ton/ha
CFA
E, 22.5 ton/ha
CFA plus 6.3
ton/ha MSS
F, 22.5 ton/ha
CFA plus 22.5
ton/ha MSS
Results of some case studies in Greece
China – Greece bilateral project
Field experiment - Results
Treatm
A, no
Plant Cu,
mg/kg
Plant Zn, mg/kg
Plant Fe, mg/kg
Plant Mn,
mg/kg
5.09a
3.09ab
0.90a
1.21a
8.38bc
3.21ab
1.73b
3.47b
8.67cd
3.51abc
1.97b
3.65b
9.14cd
4.76bc
1.60b
3.10
7.54b
2.97a
1.67b
3.17b
9.97d
4.14c
1.57b
3.37b
amendments, no
fertilizers
B, inorganic
Fertilizers
C, 22.5 ton/ha
CFA
D, 67.5 ton/ha
CFA
E, 22.5 ton/ha
CFA plus 6.3 ton/ha
MSS
F, 22.5 ton/ha CFA
plus 22.5 ton/ha
MSS
Effects of Land Application of CFA
• Biological properties (Basu et al., 2009)
– Inhibition of microbial respiration, enzymatic activity, N
mineralization and nitrification mainly due to the excessive
levels of soluble salts and trace elements in un-weathered
CFA and high pH.
– Reduction of growth of soil born pathogenic
microorganisms.
– Increase of Rhizobium sp and P-solubilizing bacteria.
– Class of CFA does not cause negative effects on microbial
communities and improves populations of fungi including
arbuscular mycorrhizal fungi .
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Constraints of CFA application to the land
• Application cost
– High handling and transportation cost
• Due to pozzolanic nature, formation of
compacted or cemented layers in case of
excessive application
• Increase of soil salinity
• Increase of toxic heavy metal concentration
and uptake by plants
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Co-application of CFA with organic soil amendments
Co-application of CFA with Sewage Sludge (SS) or manures when
applied in appropriate amounts can help to mitigate their
undesirable effects when they are applied alone and
enhance their beneficial effects.
Examples
– Increase of organic carbon content which is low in CFA
– Improve of the impacts of pozzollanic properties of CFA
– Decrease availability of toxic trace elements content in
both amendments
– Reduce acidification due to organic matter mineralisation
of SS
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Use of CFA for remediation of contaminated lands and
waters
Contaminated soils
• Decrease metals availability through pH increase due
to alkaline CFA application
• Decrease organic-micro-pollutants (pesticides and
herbicides) due to CFA high sorption capacity
Contaminated waters
• Removal of TEs and pesticides from contaminated
wastewaters using alkaline CFA
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
CFA and carbon sequestration
• Recent research showed that CFA application reduces CO2
emission through a mechanism called carbonation (Ro, 2012,
J. Soils Sediments).
• In addition it was found that CFA application increases activity
of peroxidase, which is a soil carbon stabilization enzyme and
reduces dissolved organic carbon due to the adsorption of
carbon in fly ash (Masto et al., 2014, Energy Sources).
• It means that we should investigate more deeper the
utilization of CFA for reducing CO2 emissions .
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Summary and conclusions
• Coal Fly Ash management is a serious problem
worldwide
• Agricultural use of CFA seems to be an interesting
alternative
• Advantages
– Improves some soil physical, chemical, and biological
properties (texture, pH, water retention capacity, porosity,
surface area, essential macro and micro to plant growth
nutrients, increases nutrient uptake by the plants and their
growth and yield, reduces soil born pathogenic organisms, and
increases rhizobium and P-solubilizing bacteria.
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
Summary and conclusions -continued
• Constraints:
– Inert material, low in organic carbon, low N, and P content
– Rich in potentially toxic heavy metals and high in soluble
salts
– Application cost
• Co-application of CFA with Sewage Sludge (SS) or manures
when applied at appropriate amounts may mitigate their
undesirable effects caused when they are applied alone and
enhance their beneficial effects.
• The utilization of CFA for Carbon sequestration in soils must
be further investigated.
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014
THANK YOU
FOR YOUR ATTENTION
International Workshop on the Use of Coal Ash in Agriculture.
National Coal Ash Board. Tel-Aviv , Israel 27-9 May, 2014