Influência da concentração de lodo sobre a capacidade de oxigenação do aerador e a influência da concentração do sal sobre a capacidade metabólica do lodo.

Abstract

The power consumption is a major factor to be considered in operational costs for an activated sludge system, this because the electric motors commonly used energy demand to ensure aeration of mixed liquor. In this study we assessed the influence of the concentration of sludge (biomass) on the oxygen capacity of the aerator. The oxygen transfer rate was determined in laboratory scale using the dynamic method, in the presence of microorganisms, using respirometric. In this case, the aerator was connected to the respirometer that controlled aeration. The respirometer activated the aerator when the DO concentration reached a lower limit set by disabling it when it reached an upper limit also established, beginning thus cycles of periods with and without aeration. The results revealed in systems with mixed liquor sludge with high concentration of approximately 16 gSST/L o power consumption was at least 2 times higher than in systems with sludge concentration of around 5 gSST/L. Another study in this thesis was to evaluate the effect of high salt concentration of the metabolic activity of the sludge. The metabolic capacity was measured by means of kinetic constants; maximum growth rate and maximum rate of utilization of organic material, the salts were gradually added to the effluent in the form of sodium chloride (NaCI). To determine these rates respirometric method was used in determining the rate of oxygen consumption. The results showed that the increase in salt caused a loss in the metabolic activity of up to 60%.