Submitted to: International Ash Utilization Symposium
Publication Type: Proceedings
Publication Acceptance Date: October 18, 1999
Publication Date: N/A
Considerable amounts of flue gas desulfurization products (FGDs) are generated when S is recovered from coal burned at electrical generating plants to meet Clean Air standards. 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 eapplication as amendment to acidic soil to mitigate low pH problems (Al toxicity); provide plant nutrients (particularly Ca, S, Mg); improve soil physical properties (water infiltration, soil aggregation, particle stability); 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 benefits when used on land. Constraints to use of FGDs on agricultural land could be both insufficient or excessive amounts of CaCO3, CaO, and/or Ca(OH)2 to not raise soil pH sufficiently or to raise soil pH too extensively; 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 (As, Cd, Cr, Ni, Pb, Se) which could potentially contaminate water and pose toxicity to plants/ animals. Most chemical constraints are not and do not need to be problems for FGD use on land if these products are used appropriately.