Estudo da secagem de lodo de esgoto atraves da fritura de imersão

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The increase in the population and in industrialization resulted in an increase in the volume of wastes. Part of these wastes is the wastewater and its treatment is a basic necessity of any society. Wastewater treatment generates large amounts of residues sewage sludge - that must be treated as well due to its dangerous nature and its large quantities. The objective of this work was to treat the sewage sludge, residue of a wastewater treatment plant, using a fry-drying processo Experimental work was developed in three different institutions, Unicamp (Br), University of Queensland (Au) e Ecole des Mines (Fr). The frying experiments were carried out in commercial fryers modified with the addition of thermocouples, agitators and a analytical scale. Some materiaIs like wood, baker s yeast and potatoes were fried in preliminary tests, besides the sewage sludge from the different plant dose to where the institutions were located. Curves of variation of the moisture content with time were obtained for the cited materiaIs and all curves were typical of drying processes, with the advantage that the frying process is quite faster. During the frying of sewage sludge, it was verified that, in relation to the parameters: initial mass, oil temperature, oil type and geometry of the sample, the factor geometry was the most influent on the drying rate, at least within the range chose for the variables studied. Besides the drying curves, other two important parameters were analyzed: oil uptake and calorific value. The percentage of oil into the sewage sludge sample went from 0,18% (in natura) to a medi um value of 30% to the fried sludge, depending on frying time. This increase is directly related to the loss of water during drying. The calorific value of the samples increase with frying time, reaching values around 24MJ/kg after 600s of frying. This energetic value is in the same leveI as the value for known bio-combustibles as wood as sugarcane bagasse. The process of immersion frying showed a great potential to dry materials, in special sewage sludge, obtaining a product - fried sludge - with a high energetic content, increasing its value as a combustible

ASSUNTO(S)

fritura lodo esgotos oleos e gorduras alimenticias secagem

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