BENEFITS AND CONSTRAINTS FOR USE OF FGD PRODUCTS ON AGRICULTURAL LAND

Authors: Clark, Ralph; Ritchey, Kenneth; Baligar, Virupax

Submitted to: Fuel
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/1999
Publication Date: 2/5/2001
Citation: Clark, R.B., Ritchey, K.D., Baligar, V.C. 2001. Benefits and constraints for use of fgd products on agricultural land. Fuel 80:818-821.

Interpretive Summary: Considerable amounts of coal combustion products (CCPs) are generated when coal is burned for generation of electricity. To meet Clean Air standards, large amounts of sulfur dioxide cannot be emitted into the atmosphere, which means considerable amounts of a CCP called flue gas desulfurization products (FGDs) are produced. CCPs are the third most abundant natural resource material behind crushed stone and sand/gravel and ahead of cement and iron ore. Presently only 29% of all CCPs and 10% of FGDs are being used, and greater amounts of these materials could be used rather than discarded. Although use of CCPs in agriculture is small compared to its use with cement, construction, road and back fills, application on agricultural lands could be important in CCP management. FGD use in agriculture include amendment to mitigate low pH surface and subsoils, provide plant nutrients, improve soil physical properties, alleviate sodic soil problems, inactivate phosphorus and reduce its runoff, develop pads t keep animals/feed dry during wet weather, and co-utilize with manures, composts, and biosolids. Constraints for use of FGDs on agricultural land could be insufficient or excessive change in soil pH, excessive soluble salts, excess calcium (Ca) induced mineral imbalances, Ca exchange of aluminum (Al) to induce Al toxicity, boron toxicity, sulfite toxicity, and undesirable amounts of toxic trace elements. Most constraints should not impose problems for FGD use on agricultural land.

Technical Abstract: Considerable amounts of coal combustion products (CCPs) are generated when coal is burned for generation of electricity. To meet Clean Air standards, large amounts of S must not be emitted into the atmosphere, which means considerable amounts of flue gas desulfurization products (FGDs) are and will be produced. Beneficial uses of FGDs are continually being sought to reduce waste, decrease cost of disposal, and provide value-added products. Beneficial agricultural uses of FGDs include application as amendment to acidic soil to mitigate low pH problems (Al and Mn toxicities); provide plant nutrients (i.e., Ca, S, and Mg); improve soil physical properties (e.g., water infiltration and soil aggregation); help alleviate soil compaction and improve aggregate stability of sodic soils; and inactivate P under high P-soil conditions to reduce P runoff. Co-utilization of FGDs with organic materials (manures, composts, biosolids) should also provide many benefits when used on land. Constraints for use of FGDs on agricultural land could be both insufficient or excessive amounts of CaCO3, CaO, and/or Ca(OH)2 in raising soil pH insufficiently or too much; excessive Ca to cause imbalanced Mg, P, and K in soils/ plants; Ca displacement of Al from soil exchange sites to induce Al toxicity in plants; high B to induce B toxicity in plants; excessive sulfite which is toxic to plants; and excessive amounts of undesirable trace elements (e.g., As, Cd, Cr, Ni, Pb, and Se) which could potentially contaminate water and pose toxicity to plants/animals/microorganisms. Most constraints are not and do not need to impose problems for FGD use on land.