Recovery efficiency of S. obliquus as a function of time at different applied currents is shown in Fig. 2b. It is clearly visible that the initial rate of microalgal recovery efficiency was high and reaction rate slowed after 30 min of reaction. This may be due to change in the ratio between charge on algal cell surface and charge ions generated at the anode. Microalgal recovery efficiency attained was 49%, 52% and 57% at 0.5 A, 1.0 A and 1.5 A respectively after an hour electrochemical harvesting process (Fig. 2b). From Fig. 2b it is noticeable that the difference between microalgal recovery efficiency at 0.5 A and 1.0 A is large and becomes constant after 30 min of reaction. In this investigation, after technoeconomic evaluation the applied current of 1.0 A was found to be the optimum value when considering the energy consumption and the algae recovery efficiency simultaneously.