Evaluation of revegetation techniques of a saline flue gas desulfurization sludge pond

Codisposal of flue gas desulfurization (FGD) sludge with low-volume generating station waste simplifies disposal but creates a saline, high-boron (B) waste that may be difficult to revegetate after site closure. Studies on a delta of waste material in a codisposal pond in eastern Arizona evaluated management techniques, amendments, and plants for revegetating this material. One study investigated leaching and ridging techniques and a second evaluated amendment with manure, wood shavings, and fly ash. Four salt-tolerant grass species and four saltbushes (Atriplex spp.) were evaluated in the two studies. Criteria for success were high survival rates and growth, as measured by grass height and shrub height×width. Leaching salts and B from the waste was not necessary for establishment and growth of transplanted shrubs and grasses. Ridging was not a successful technique, due to limited moisture and high levels of salinity and B on these structures. Gardner saltbush and [A. gardneri (Moq.) D. Dietr.] and a fourwing saltbush [A. canescens (Pursh) Nutt.] accession from the site were the most successful shrubs and alkali sacaton [Sporobolus airoides (Torr.) Torr. `Saltalk'] was the most successful grass at this disposal pond. Amendment with manure, wood shavings, or fly ash did not increase plant survival. Growth of grasses was improved with all amendments and was greatest with manure, but growth of shrubs was not improved with any amendment.