Viability of Ash Recycling As a Disposal Option Following Conversion of a Coal-Fired Power Plant to Biomass.

The Southern Company is evaluating conversion of several coal-fired power plants, including Plant Mitchell near Albany Georgia, to the combustion of woody biomass and agriculture residues. Part of this evaluation is an evaluation of ash disposal and recycling options. Ash generated from biomass combustion represents a large portion of nutrients removed during harvest. Land application of biomass ash is one way of recycling these nutrients back to the land while reducing disposal cost. Although the beneficial use of biomass ash as a soil amendment is well documented from a biological perspective; developing an economically-feasible land application program is dependent upon key factors that are locally-specific, such as, the proximity and spatial distribution of agricultural and forest lands, the specific ash characteristics’ potential for utilization by agricultural and forest type land uses, and the cost of distribution.  This information was used in a GIS-based study of the feasibility of recycling biomass ash from Plant Mitchell. We found recycling to be economically viable for hauling distances less than 20 miles. Assuming ash was utilized at current lime utilization rates; sufficient agricultural land was available within 16 miles to handle ash produced by Plant Mitchell. Our assumption that ash can replace traditional liming materials is currently being tested in field studies.