Selected Species and Amendments for Revegetating Saline Flue Gas Desulfurization Sludge: Greenhouse Study

Abstract

Codisposing low-volume wastes from electrical generating stations with flue gas desulfurization (FGD) scrubber sludge simplifies waste disposal but produces a saline waste that presents unique challenges to revegetation. This greenhouse study identified plants and amendments for revegetating a saline FGD sludge disposal pond in eastern Arizona. Survival and growth of 16 sown accessions plus two vegetatively propagated accessions of inland saltgrass [Distichlis spicata var. stricta (Torr.) Beetle] were investigated in saline FGD sludge (ECₛₑ = 6.65 S m⁻¹). Amendments used included two soils from the disposal site, Claysprings gravelly clay (Typic Torriorthent) and Sheppard sand (Typic Torripsamment), composted steer manure, and N-P-K fertilizer. Soils and manure were added at 2:1 sludge/amendment (v/v). Plants were irrigated with a 1:1 mixture of disposal pond water and untreated well water (EC = 2.09 S m⁻¹). One accession of inland saltgrass, two cultivars of tall wheatgrass [Elytrigia pontica (Podq.) Holub ‘Largo’ and ‘Jose’], Altai wildrye [Leymus angustus (Trin.) Pilger ‘Praireland’l, tall rescue (Festuca arundinacae Schreb. ‘Alta’), and alkali sacaton [Sporobolus airoides (Torr.) Torr. ‘Saltalk’] show promise for revegetating saline FGD sludge disposal sites. Survival rates were the same in unamended sludge and in sludge amended with the clay soil or with N-P-K fertilizer. Plant dry matter produced was the same in unamended sludge and in sludge amended with either of the soils or with N-P-K. Although survival rates were significantly lower with manure than with any other amendment, due to high EC values, growth was significantly greater by all measurements, due to the high fertility of this treatment. Contribution from the Dep. of Soil, Water, and Environ. Sci., Univ. of Arizona, Tucson.