To determine the microalgal harvesting efficiency of microalgal
biomass, also termed as recovery efficiency, samples were collected at different time points (t) during the ECH process. Samples
were collected at 5 cm below the water surface in the ECH reactor.
In the ECH reactor, flocs of microalgae floated to the top surface of
microalgal broth. Flotation of the flocs was caused by the formation of H2 at the cathode and O2 at the anode. The microalgal recovery efficiency was determined based upon the decrease in optical
density of the microalgal suspension (measured at 680 nm with a
UV–VIS spectrometer, Spectroquant Pharo 300, Merck). The percentage recovery efficiency was subsequently calculated