Avaliação dos parâmetros cinéticos de biomassa gerada em sistemas de lodo ativado.

Abstract

ABSTRACT Activated sludge systems are different from other systems of biological sewage treatment due to their capacity to remove organic material and nutrients with different configurations such as continuous flow and sequential batch systems. The oxidation of organic matter and the nitrification process are key points for the removal of nitrogen and organic material from wastewater and are performed by specific bacteria groups, heterotrophic and autotrophic, respectively. The characterization of the kinetics of these groups in three different activated sludge systems was the aim of this study. Sequential batch reactors systems (RBS) with a single reactors and with dedicated reactors for nitrification and denitrification as well a flow through system (UCT) were assembled and operated to determine the kinetic parameters the bacterial mass: Specific Oxygen Consumption rate ( SOUR ) , substrate consumption rate constant ( Kms ) and maximum specific growth constant (μm ) for the heterotrophic and , and the , maximum specific growth constant ( μm ) and halfsaturation constant (Kn ) for autotrophs. Respirometry was used for these determinations. The influence of the of system configurations ( RBS - Unit , RBS - airlift and UCT ) and operating conditions on the autotrophic and heterotrophic metabolism was evaluated. The systems were subjected to two stages in which the composition of the wastewater was different with respect to the concentration of biodegradable organic material and the organic loading rate. The results showed differences in efficiency between the stages systems, both in terms of removal of organic matter and nutrients. The metabolism of heterotrophic bacteria showed differences in the kinetic values between the stages, whereas autotrophics showed differences between the studied configurations.