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