Abstract

Kraft mill generates a large amount of dregs (D) and grits (G) as solid wastes due to the causticizing process. The disposal of these wastes is expensive in terms of land requirement and maintenance. On the other hand, solid wastes have alkalinity and buffer properties, which make them appropriate for use as amendments to acidic soils. The goal of this work was to determine the physical, chemical, toxicity and hazardousness characteristics of D & G. Additionally, the effect on acidic soils' physical properties after mixing with these wastes as well as potential leach properties were evaluated. Hazardousness (inflammability, reactivity, corrosivity) and toxicity (due to inorganic compounds) assays on D & G indicated that their values are below the EPA Standard. Additionally, physicochemical characterization (pH (12.76), Ca (26.5%), Mg (1.5%), P (0.28%) and K (0.20%)) confirms their potential use in degraded solids. To study the amended soils' leaches, the behavior of a series of columns with acid soils and D&G (1:1) at rates of 2 and 6 g kg-1 was evaluated during 86 d. The physicochemical characteristics of the amended soils were improved by D&G incorporation. © 2007 Sociedad Chilena de Química.