Microalgal recovery efficiency for C. sorokiniana microalgae at different applied electrical current and at various times was evaluated and is depicted in Fig. 2a. Preliminary laboratory testing of the ECH reactor involved determining the effect of applied electrical current on the recovery efficiency of C. sorokiniana After one hour the recovery efficiency was nearly 60%, 66% and 79% at 0.5 A, 1.0 A and 1.5 A respectively. According to the results it is clearly visible that for the ECH process of C. sorokiniana microalgae at 1.5 A, it shown maximum efficiency in terms of microalgal recovery. It is well known that electrical current not only determines the flocculation process rate but also the bubble production rate and size and the flocs growth which can influence the treatment efficiency of the electrochemical harvesting process. As expected, it appears that for a given time, the microalgal recovery efficiency increased significantly with increase of applied current