A new kinetic approach to microbial storage process

In this work, a new kinetic approach was proposed to describe the microbial growth, substrate consumption, and formation and utilization of the intracellular storage products (X _STO) in activated sludge. It was found that the formation of X _STO was coupled with energy generation and respiration and that the X _STO formation rate was proportional to the substrate utilization rate. A high amount of external substrate resulted in a relatively rapid storage process with a large fraction of substrate electrons for X _STO formation. The maximum growth rate of active biomass on X _STO and the yield coefficient for growth on the storage polymers were estimated as 0.12 h⁻¹ and 0.60 g chemical oxygen demand (COD) _X g⁻¹ COD_STO, respectively. This established model was verified with the experimental results from two different case studies with pure and mixed cultures. Results showed that this kinetic model was able to accurately and mechanistically describe the microbial storage processes.