Modelling of activated sludge processes with structured biomass.

The model was developed using observations from both pure and mixed cultures under dynamic feast-famine conditions. The researchers focused on RNA and protein synthesis as indicators of growth readiness. They hypothesized that these systems are activated only in the presence of external substrates. The model structure was designed to simulate substrate diversion toward growth or storage. Dynamic experiments provided data for model validation. Key parameters included PHA turnover rates and growth phase transitions. The model was tested against observed behavior in sequencing batch reactors (SBRs). The evaluation focused on predicting mixed culture responses accurately.

The proposed model successfully predicted PHA turnover in bacterial cells under dynamic conditions. It described mixed culture SBR behavior with reasonable accuracy. However, the model overestimated growth rates during the famine phase. RNA and protein synthesis dynamics were central to the predictions. The model's structure aligned with observed substrate allocation patterns. PHA accumulation and utilization phases were captured effectively. Growth phase predictions showed some discrepancies, particularly in low-substrate conditions. The model provides a mechanistic basis for future improvements in activated sludge modeling.

The model contributes to mechanistically based descriptions of activated sludge processes. It successfully captures PHA turnover and overall SBR behavior. However, the overestimation of famine-phase growth rates indicates room for refinement. The model is based on RNA and protein synthesis dynamics observed in dynamic cultures. The authors suggest further development to improve accuracy in low-substrate conditions. This framework provides a foundation for more precise simulations. The model's structure reflects observed substrate allocation patterns. Future work should focus on validating predictions against additional experimental data.