Photobioreactor connected to complete mixed unit for mass transfer
A continuous 2.2 L photobioreactor was operated coupled to a 0.13 L vessel as gas/liquid mass transfer unit (Fig. 1). Microalgae culture was continuously circulated between the photobioreactor and the mass transfer unit. The system was operated injecting a gas mixture simulating biogas (70% N2 ; 30% CO2) in the mass transfer unit. Gas injection was controlled on-line in order to keep the photobioreactor pH in the range 7.5e8.0. Gas recirculation was applied in the mass transfer unit, so it was assumed that its hydraulic behaviour was that of a complete mix compartment. Applied dilution rate in the photobioreactor was 0.06 d?1(feed flow of medium:0.144 L d?1)