TREATMENT OF BOTTOM SLUDGE FROM FACULTATIVE LAGOONS WITH STABILIZATION IN LABORATORY CONDITIONS TREATMENT OF BOTTOM SLUDGE FROM FACULTATIVE LAGOONS WITH STABILIZATION IN LABORATORY CONDITIONS

Abstract

In this paper we show the results obtained from the chemical stabilization process of pond sludge by adding common hydrated lime. Doses of lime at 5%, 7%, 9%, 10%, 11%, 12%, and 15% were added in controlled laboratory conditions to a sample of sludge taken from the bottom of the primary facultative pond of the wastewater treatment system in Monteria in Colombia. The sludge’s dangerousness (corrosiveness, flammability, and reactivity) and concentrations of sulfides, heavy metals (As, Ba, Cd, Cr, Hg, Ag, Pb, Se), coliforms, Salmonella, mesophilic bacteria, Ascaris lumbricoides, and other helminths were analyzed in the sludge sample before and after application of an optimal 10% dose. The reactivity due to sulfides and cyanides in the sludge sample was controlled with this dose, but coliforms and mesophilic bacteria concentrations did not decrease. Some heavy metals (Cd, Cr, Hg, Ag, Pb) increased after application of the hydrated lime dose, although the concentrations found do not pose environmental danger according to existing environmental regulations.