ABSTRACT
A simple model is developed for membrane fouling, taking into account two main fouling phenomena: cake formation, due to attached solids on the membrane surface, and pore clogging, due to retained compounds inside the pores. The model is coupled with a simple anaerobic digestion model for describing the dynamics of an anaerobic membrane bioreactor (AnMBR). In simulations, we investigate its qualitative behavior: it is shown that the model exhibits satisfying properties in terms of a flux decrease due to membrane fouling. Comparing simulation and experimental data, the model is shown to predict quite well the dynamics of an AnMBR. The simulated flux best fits the experimental flux with a correlation coefficient r2=0.968 for the calibration data set and r2=0.938 for the validation data set. General discussions are given on possible control strategies to limit fouling and optimize the flux production. We show in simulations that these strategies allow one to increase the mean production flux to 33 L/(h·m2),whereas without control, it was 18 L/(h·m2).
ABSTRACT
This paper deals with a mathematical analysis of two-steps model of anaerobic digestion process, including dynamics of soluble microbial products (SMP). We propose to investigate effects of the new variable SMP on qualitative properties of the process in different generic cases. Equilibria of the model are graphically established considering qualitative properties of the kinetics and, their stability are proved theoretically and/or verified by numerical simulations. It will shown that the model has a rich qualitative behavior as equilibria bifurcation and multi-stability according to the considered bifurcation parameter.
Subject(s)
Anaerobiosis , KineticsABSTRACT
An Anaerobic Membrane BioReactors (AnMBR) model is presented in this paper based on the combination of a simple fouling model and the Anaerobic Model 2b (AM2b) to describe biological and membrane dynamic responses in an AnMBR. In order to enhance the model calibration and validation, Trans-Membrane Pressure (TMP), Total Suspended Solid (TSS), COD, Volatile Fatty Acid (VFA) and methane production were measured. The model shows a satisfactory description of the experimental data with R2≈0.9 for TMP data and R2≈0.99 for biological parameters. This new model is also proposed as a numerical tool to predict the deposit mass composition of suspended solid and Soluble Microbial Products (SMP) on the membrane surface. The effect of SMP deposit on the TMP jump phenomenon is highlighted. This new approach offers interesting perspectives for fouling prediction and the on-line control of an AnMBR process.
