Enzyme transmission during crossflow filtration of yeast suspensions using gas/liquid two-phase flows.

The optimal conditions for recovery of an enzyme were determined using gas/liquid two-phase flows. When filtering the enzyme-only solution under single-phase flow conditions, severe fouling occurred. This fouling was manifest as a decline in flux to less than 2% of the initial water flux and a decline in protein concentration in the permeate to 30% of its initial value, during a five-hour filtration period.

Why and how membrane bioreactors with unsteady filtration conditions can improve the efficiency of biological processes.

A membrane bioreactor (MBR), an association of a bioreactor with a crossflow filtration unit, enables continuous processes with total cell retention within the reactor to be realized. Provided that high dilution rates can be applied and that inhibition processes are avoided, very high biomass concentrations can be reached, thereby improving the volumetric productivities. These membrane bioreactors have been successfully applied to various microbial bioconversion, such as alcoholic fermentation, solvents, organic acid production, starters, and wastewater treatment.

Enzyme recovery during gas/liquid two-phase flow microfiltration of enzyme/yeast mixtures.

The effect of a gas/liquid two-phase flow on the recovery of an enzyme was evaluated and compared with standard crossflow operation when confronted with the microfiltration of a high-fouling yeast suspension. Ceramic tubular and flat sheet membranes were used. At constant feed concentration (permeate recycling) and transmembrane pressure, the results obtained with the tubular membrane were dependent on the two-phase flow pattern.

Feasibility study of a compact process for biological treatment of highly soluble VOCs polluted gaseous effluent.

Volatile organic compounds (VOCs), representing a wide range of products mainly generated by industrial activity, are involved in air pollution. This study deals with a new biological treatment process of gaseous effluent combining a gas/liquid contactor called an "aero-ejector" and a membrane bioreactor. Combining these two innovative technologies enables a high elimination efficiency to be reached.

Influence of a transverse flowrate on the oxygen transfer performance in heterogeneous aeration: case of hydro-ejectors.

This paper deals with the scaling of aeration devices, and more specifically hydro-ejectors, in the case of heterogeneous aeration. Because the transfer of oxygen only occurs in a very small part of the volume of the treatment basin, the transfer performance of the aerator depends on the device itself and on the surrounding flow characteristics. First experiments were achieved with a 10 L mechanically agitated reactor in order to operate at a known kLa and liquid flowrate Q.