Dynamic modelling of a single-stage high-rate anaerobic reactor—I. Model derivation

A structured model of the anaerobic degradation process, incorporating dynamic equations for the description of a single-stage high-rate anaerobic reactor was validated by comparing its predictions with previously reported experimental data. This data came from two different laboratory-scale reactors and a pilot-scale reactor. With the manipulation of key model parameters, significant improvements in the fit of the model to the experimental data were possible. This study was able to show that the production and consumption of lactic acid, and the moderate hydrogen inhibition and regulation of the acidic products of the acidogenic bacteria, can be successfully modelled. Insufficient experimental data were available to draw conclusions as to the importance of product inhibition in anaerobic reactors, while the need to use deterministic models to account for pH inhibition highlighted the need to develop mechanistic models able to reflect the pH inhibited behaviour of the major anaerobic groups present in the ecosystem.