The Effects of Modified Flue Gas Desulfurization Residue on Growth of Sweet Potato and Soil Amelioration

We report on treatment and disposal of flue gas desulfurization (FGD) as a solid and hazardous waste. The effects of modified flue gas desulfurization residue (MFGDR) prepared by calcining a mixture of dry/semi-dry FGD residue, potassium feldspar, and/or limestone power on growth of plant and soil amelioration are investigated. The effect of MFGDR on the sweet potato was evaluated by analyzing the soil physiochemical properties and heavy metal speciation in the soil, and the yield, quality, and heavy metal concentrations of the sweet potato. The results indicated that applying MFGDR as soil ameliorant increased total yield by 53.38 %, safety, and the quality of sweet potato. The concentrations of Cd, Cr, Cu, Pb, and As in the sweet potato reduced by 31.34, 70.57, 22.17, 79.49, and 100 %, respectively. The improvements were attributed to enhancement of soil mineral composition contained in MFGDR. The MFGDR could also improve the soil physicochemical properties and decreased phytoavailability of heavy metals. The application of MFGDR in agriculture not only was a potential and useful technique for recycling and utilization of FGD residue, but also had potential benefits for soil amelioration, plant growth, and decrease of heavy metals in grown products.