Avaliação da quantidade de nitrogênio e de microrganismos patogênicos em lodo anaeróbio higienizado com cal para reúso agrícola.

Abstract

Domestic sewage contains microorganisms that associate to solid particles to form sewage sludge. The sludge also contains nutrients, which favours its use as organic fertilizer, after alkaline treatment. The purpose of this experiment was to evaluate the modifications occurred in the characteristics of the sludge and its agricultural potential after alkaline treatment with Ca(OH)2. The concentrations of Ca(OH)2 used in the treatment increased the sludge pH to above 12 and provoked an unfavourable environment for the survival of pathogenic microorganisms. The data showed that sludge treated with Ca(OH)2 can be used for the correction of acid soils or as organic fertilizer, provided the relation between soil fertility and plant nutrient requirements is known.