Determinação de propriedades bioquímicas e mecânicas de biomassas de sistemas de lodo ativado para concepção de projetos otimizados

Abstract

This research aimed to study the conditions of the biochemical and mechanical properties of biomass of activated sludge systems (SSLM) and define an interface for the application of these properties in the design of projects, based on a model of activated sludge. Thus, the research was divided into two parts: (1) study the conditions of the biochemical and mechanical properties of SSLM and (2) the elaboration and application of activated sludge model. During the first stage we studied the conditions for obtaining measurements of dissolved oxygen and its influencing factors, as well as a study on the respirometry. Still in this stage are two methods of determining the kinetic constants of sedimentation were evaluated. The second stage consisted of 6 experimental operation of activated sludge systems, where each system tied up to a specific treatment goal. With experimental data obtained from activated sludge systems, elaborated a simplified procedure for predicting the cycle time and the optimal treatment volume in each treatment goal. The results showed that the first stage membranes which have less than 5 min

-1 K rel lead to impairments of determining the TCO. Results obtained in the first phase also showed that the selection of the respirometric test conditions may exert negative influence when we work under the following conditions: 15 s < λ < 5 s, SSLM concentration of > 5 g L -1 and EC > 1 mS / cm 2 . Focusing on respirometric procedures, that is attested sodium acetate (CH 3 COONa) can be considered as a good representative pattern for the heterotrophic metabolism studies and ammonium bicarbonate (NH 4 HCO 3 ) to study the nitrifying autotrophic metabolism. Is testified also that biomass showing ability to biodesfosfatação difficult in general to determine the constants related to the metabolic properties and that we should therefore give attention to these cases. It was possible to establish that the sodium azide (NaN 3 ) is an excellent inhibitor selective nitration at a concentration of 1 mg L -1 , thus allowing the study of nitrification in two steps. In the second stage, the three studied phases, the third phase was that the systems showed the best performance of removal of constituents within the proposed objectives, and that the sizing procedures were able to predict the operating conditions for RBS systems satisfactorily.