A new approach for modelling simultaneous storage and growth processes for activated sludge systems under aerobic conditions

Abstract

By critically evaluating previous models, a new mechanistic model is developed to describe simultaneous storage and growth processes occurring in activated sludge systems under aerobic conditions. Identifiability was considered an important criterion during the model development since it among others helps to increase the realiability and applicability of models to full-scale WWTPs. A second order model was proposed for description of the degradation of the storage products under famine conditions. The model is successfully calibrated by only using OUR data obtained from batch experiments. Calibrations were performed with biomass from full-scale WWTPs in Belgium and Spain. Predictions of the calibrated model were successfully confirmed using off-line PHB measurements, supporting the validity of the model. An iterative experimental design procedure was successfully applied and found to remarkably improve the parameter estimation accuracy for the growth on storage parameters K1 and K2, which used to have large confidence intervals when using standard experiments. The estimated biomass growth yield on substrate (0.58 mgCOD/mgCOD) is quite close to the theoretically expected range for heterotrophic growth. This became possible by properly accounting for the storage process. Moreover, the maximum growth rate was predicted in the range 0.7-1.3 per day. This range, albeit quite lower than the values reported for the growth-based ASM models, is believed to be more realistic. Finally, the new model is expected to better and more mechanistically describe simultaneous storage and growth activities of activated sludge systems and as such could contribute to improved design, operation and control of those systems.

Direct metabolic activity measurement for unstable bioprocess experiment control

“…For microbial sludge treatment plant biomass growth rate is relatively low and-as confirmed experimentally-accumulation is the predominant reaction (Sin et al [5]). Numerous studies confirm that the observed changes in the transient behaviour of activated sludge are related to the changes in metabolic pathways corresponding to the primary and secondary growth phases.…”

Mathematical simulating the process of aerobic granular sludge treating high carbon and nitrogen concentration wastewater

“…For the model calibration, the initial concentration of active biomass X Hð0Þ , was estimated using the initial OUR level (Eq. (7)) without any substrate addition [35].…”

Modeling and simulation of the sequencing batch reactor at a full‐scale municipal wastewater treatment plant

“…Parameters are assigned with initial values for calibration from literatures as shown in Table 6. 10,29 In this work, the most important model output variables of COD, NH 4 þ -N and MLVSS concentrations are analyzed as shown in Figures 2-4.…”