Contribuição para o dimensionamento de leitos de secagem de lodo.

Abstract

This is a dissertation about a study of the behaviour of a natural drying bed for sludge, whith aptypical loads, larger than those recommended by the Brazilian norms (15kgSST/m2). Sludge drying with upward insuflation of air was also investigated. The reserach about natural drying was carried out with two types of beds, covered and uncoveredand, subject to atmosphenc conditions. Artificial drying consisted in blowing air in upward direction through sludge beds loaded with up to one meter of humid sludge, corresponding to a load of 312kgSST/m2. Evaporation of a layer of 250 mm of water was obtained in 45 days. Initially the dissertation presents a very brief history of the evolution of the destionation of human wastes. In its development a literature review is presented, in which the physical and atmospheric studies are reviewed. The data were collected over a period of march to june 2005, at Campina Grande, where the mass of evaporated from sludge samples as well as the solar radiation was measured by a radiometer connected to a micro-computador so that readings were taken every five minutes. These data were used and methods of mathematical modeling were applied to evaluate the obtained data. In its conclusion it was indicated which would be the optimal load to be applied on natural drying beds for the climatic conditions of Campina Grande-PB.