Flue Gas Desulfurization Gypsum Agricultural Uses
USDA-ARS, J. Phil Campbell Sr.
Natural Resource Conservation CenterWatkinsville, GA
Dr. Harry H. Schomberg
What is Gypsum?
• CaSO4 . 2H2O (gypsum)• CaSO4 (anhydrate)• Used by Greeks and Romans• Fertilizer value recognized in 1800s• S and Ca – Plant nutrients
250 μm
Energy & Environmental Research Center
Lime slurry spray
Zimmer StationCinergy Corp.
Ohio State University Extension 2005
Flue Gas Desulfurization Process
Physical & Chemical Properties Gypsum Sources
Material Water Ca S As Hg Particlesize
Residue Price(2002)
% % % mg/kg mg/kg % $/tonFGD gypsum
5.55 23.0 18.7 0.56 <0.26 120 μm 0.4 7.00
Naturalgypsum
0.38 19.1 15.1 <0.52 <0.26 NA 12.9 12.75
Castgypsum
0.15 22.4 19.3 <0.52 <0.26 NA 0.2 NA
Drywallgypsum
10.1 21.9 18.1 0.98 <0.26 <0.5 in 2.2 11.00
EPA 503 41 17
Ohio State University Extension 2005
USDA Strategic Plan• Protect and enhance the
nation’s natural resource base and environment
• Protect watershed health to ensure clean and abundant water
• Enhance soil quality to maintain productive working cropland for food, feed, fiber and energy production
Effects of Gypsum on Soil
• Improve soil structure • Improve water infiltration,
storage and use • Improve crop yield and quality • Remediate saline and sodic soils• Reduce movement of nutrients, sediment
and agricultural chemicals to water and air
Conservation Issues in the Southeastern US
• Many of the soils are of poor quality and highly susceptible to erosion
• Large number of water bodies in the region are impaired by contaminants (sediment, nutrients, agricultural chemicals)
• Many areas in the region are suffering from drought
Soil Degradation
• Accelerated soil erosion• Loss of organic matter• Soil compaction• Soil acidification• Buildup of soluble salts,
and toxic trace elements
Results of Soil Degradation
• Reduced crop yields• Greater inputs
required for crop production
• Greater risk of environmental damage
Gypsum Improves Yields
Sumner, 2007
Gypsum and Acid SoilsIncreases subsoil calciumReduces subsoil aluminum (toxic)Allows roots to penetrate subsoilsIncreases potentially available water
Al3+ Al3+ Al3+
Al3+ Al3+ Al3+
Al3+ Al3+
Al3+ Al 3+ Al 3+
Gypsum Application
Al3+ Al3+ Al3+
Al 3+ Al3+ Al3+
Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+
Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+
Crop
Soil Crusts
(Mark Licht)
(Palle Pedersen)
OSU Extension 2005
Gypsum Reduces Erosion
Gypsum Infiltration Runoff Soil LossMg/ha mm mm Mg/ha
0 7 50 213.6 13 44 136.7 21 36 8
13.4 24 32 5
Norton and Rhoton, 2007
0
10
20
30
40
50
60
70
Blount Catlin Fayette Miami
Tota
l inf
iltra
tion,
mm
ControlGypsum
Gypsum Increases Infiltration
USDA-ARS NSEL, West Lafayette, IN)
Georgia’s Water Crisis
Uses 6.5 Billion gallons water per day!(22% by greater Atlanta)
Georgia’s Water Crisis
• 705 Billion gallons/year • 109 Days of Georgia’s Total Annual Needs . . • 2.5X to 7X quantity of water used annually for
irrigation of row crops in Georgia. . • 1.37 years of Atlanta’s annual usage . .
• FGD Gypsum on 3.5 million acres • Assume 15% increase in infiltration of
annual rainfall
FGD Gypsum to Remediate High Soil P
• Top five - GA AR AL MS & NC• 5.2 billion broilers• 7.8 million tons broiler litter• 233,000 tons N• 116,000 tons P
High Soil P
Percentage of SamplesP > 450 lb / acre
0% - 10%10% - 30%
University of GeorgiaSoil, Plant and Water LabSoil Phosphorus Levels1999-2002
FGD Gypsum to Remediate High Soil P
Franklin et al., 2007
Broiler LitterFiltered
NO3-N P PO4-P
Run
off (
mg
L-1 )
02468
102530354045
GypsumNone
76% reduction in
Dissolved TP!
Agronomic Unknowns FGD-Gypsum
• Optimal application rates • Effects on macro and micronutrients• Influence on P availability from manures• Crop response – moisture stress
Environmental Unknowns FGD-Gypsum
• Long-term effects – crop and animal • Bioaccumulation potential of Hg• Rate of vertical movement of Hg in soils • Potential volatilization of adsorbed
emissions
Metal Uptake by Peanuts – GA (EPA3052)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
As 0.1Cr 0.1Cu Cd Hg Pb Se
mg/
kg in
Pea
nut s
eed
ControlGypsum
What if?• 1 acre of soil is 1,000 tons (6 ¾ inch depth)• 250 - 500 ppb Hg FGD gypsum • Hg in typical soil –
100 ppb • 1 to 4.5 tons/acre • 17 ppm Hg limit
EPA 503
0102030405060708090
100
1 2 3 4 5 6 7 8 9 10Applications
Soil
Hg
ppb
6 ton4 ton2 ton1 ton
Research Activities
• Determine benefits and risks of FGD gypsum• Develop management practices and
technologies to – (1) improve soils for crop production and
environmental protection and – (2) remove agricultural contaminants from
water• Document benefits to support USDA
Conservation Programs and Environmental Credit Trading
ARS FGD Gypsum Research in SE
Coastal Plains
PiedmontMississippi Valley
Loess Plains
Oxford
AuburnWatkinsville
Field Experiments
• Develop guidelines for specific uses of FGD gypsum – where to use, rates, method of application,
frequency of application, etc.)• Assist USDA Natural Resources
Conservation Service in process to accept practices as eligible for Conservation Program funding
Field Experiments
• 3-4 years• Sites with different soils, climate, cropping
systems• Comparison of FGD gypsum to mined
gypsum
Field Experiments
• Soil properties– soil structure, – water infiltration, – storage of water – reduced runoff and erosion
• Document movement of trace elements such as Hg to surface and ground water
Watkinsville, GA
Co-application• Improve P management• Improve soil structure and
increase water availability• Reduce runoff and losses
of soil and nutrients
FGD-Gypsum & Poultry Litter
Watkinsville, GA
Rainfall Simulation
Total Runoff and Sediment
Nutrients in Runoff
Nutrients in Sediment
Expected Outcomes
• Guidelines for use of FGD gypsum– Water conservation– Water quality– P management
• Support for adoption of FGD gypsum as BMP – Conservation Security Program– Environmental Quality Incentives Program$$
Partnerships
• Cooperation among a variety of groups including: ARS, EPA, NRCS, Universities, Southern Company, TVA, Duke Energy, EPA, EPRI, and FGD Gypsum Network
• No single group has resources to document beneficial agricultural uses of FGD gypsum
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