Avaliação do processo de secagem térmica de lodo de esgoto sanitário

Abstract

Sanitary sewage sludge is composed of a complex mixture of inorganic and organic solids. Its treatment aims to reduce the content of biodegradable organic material and moisture, in order to obtain a stable material with higher concentration of solids. It is a challenge to find economically viable and ecologically safe treatments. Among several treatments, thermal drying has been pointed out as the most capable of perfecting routines and minimizing operating costs. In this work an experimental research was conducted at the Experimental Station of Biological Treatment of Sanitary Sewers of the State University of Paraíba, Campina Grande-PB, Brazil. The objective was to analyze the convective drying behavior of sewage sludge at the following temperatures: 60, 70, 80 and 90, and variation of 2,5 ° C, as well as to select among the mathematical models presented in the literature which best represents the drying behavior of this residue. The sludge studied was collected in a UASB reactor; and the tests carried out with an initial mass of 500g of sanitary sewage sludge. It was observed that the sludge presented an initial moisture content of 92.51%, being classified as fluid or diluted sludge, reinforcing the necessity of the drying process. Among the mathematical models studied, the models of Midilli and Page presented better statistical adjustments and represented more accurately the sludge drying process among the temperatures studied. It is suggested 90ºC the temperature with better relation cost / benefit for the drying process.