O sistema de lodo ativado sob condições dinâmicas em regiões tropicais.

Abstract

In the practice of sewage treatment, the systems with suspended sludge presented a dynamic behavior. This is due to the cyclical nature of the applied organic and hydraulic load. The fundamental parameter to evaluate the behavior of these systems under dynamic conditions is the rate of oxygen consumption (TCO). Using TCO, Marais and his group of researchers developed a kinetic model that describes the use of biodegradable organic material influencing the microorganisms present in the system. This model describes the variations with time of the parameters related to the use of the biodegradable material: concentration of the organic material in the effluent, organic sludge concentration and rate of oxygen consumption. The model was tested for a temperature range of 14 to 20 ° C and has great practical applicability in projects and optimization of systems with suspended sludge, allowing to determine the capacity of oxygenation to be installed and the minimum age of sludge for removal efficient organic material. In order to test the applicability of this model to the prevailing conditions in the Northeast of Brazil, an experimental investigation of an activated sludge system was carried out in laboratory scale, operated under dynamic conditions of organic and hydraulic loads, using crude sewage Based on the results obtained, it was verified that the model is "valid for temperatures up to 28 ° C, becoming applicable for projects in tropical regions. It was possible to determine the constants that define the composition of the influent organic material and the kinetic constants describing the use of the stored material. The calculated values ​​for the organic material composition constants were similar to those found by Marais (for the temperature range of 14 to 20 ° C). However, the values ​​of the kinetic constants of use of the stored material differed.