Influence of Endogenous OUR Determination on the KLa$${K_L}a$$, Exogenous OUR, Total Oxygen Consumption and Heterotrophic Yield in a Completely Mixed Batch Reactor

Abstract

Abstract In wastewater treatment, waste removal and biomass activity are important processes which need to be monitored for a good process control. The difficulties in the interpretation of the total COD, BOD and VSS measurements encouraged the development of respirometric methods for assessing the kinetic constants. Respirometry is an important technique in assessing biological reaction in wastewater treatment. K L a $${K_L}a$$ , depends on endogenous oxygen uptake rate (OURend), is a key constant in evaluating respirogram-specific parameters. Generally, OURend is assumed constant in the dissolved oxygen equations. However, it is not the case. Consequently, this paper deals with the influence of OURend calculations region on K L a $${K_L}a$$ determination, exogenous oxygen uptake rate (OURexo), total oxygen consumption and heterotrophic yield (Y H). It was shown that the value of OURend and K L a $${K_L}a$$ varied considerably, a maximum of 56%, depending on where to consider C fin, on the oxygen concentration variation curve. Even though, the variation on OURend and K L a $${K_L}a$$ is important its influence on Yo/x and Y H is attenuated to 7.5% and 6%, respectively. This may be due to the local nature of the first parameters (OURend and K L a $${K_L}a$$ ) and the global nature of the later ones. Moreover, this can be seen through the variation of the calculated amount of oxygen consumed (QThete) which is of the order 7.6%.