In this study, electrocoagulation was evaluated for landfill leachate as a complex wastewater. Effects of all significant parameters including inter-electrode gap, current density, electrode material, time, pH, electrode numbers, salinity, and concentration were investigated. This study reports the changing patterns for chemical xxygen demand (COD) removal, temperature, voltage, and pH during EC for both Fe and Al electrodes under different conditions. According to the results, the best COD removals were achieved at shortest inter-electrode distance (0.5 cm), highest current density (1000 A m⁻²), highest number of electrodes (6 plates), longest time (60 min), and within acidic pH. Furthermore, for different NaCl concentrations (0–16 g l⁻¹), both falling and rising patterns were observed. This study also provides separate results for the effect of operational parameters on pH, voltage, temperature, and energy consumption during EC. With higher inter-electrode distances, voltage and temperature rose to larger values, whereas pH fell. Besides, increases in initial pH caused rises in all voltage, temperature and pH parameters during EC. Experiments also displayed that higher values of voltage, temperature, and pH occurred at larger current densities. Additionally, with time, pH increased to more basic measures, and voltage similarly increased. Results also reported that although addition of NaCl into medium could drop the voltage and temperature, it formed both falling and rising patterns for pH at different NaCl concentrations. Plus, according to the results, voltage, temperature, and pH all experienced rising patterns in accordance with the increase in the number of electrodes. Finally, a comparative study of energy consumption was performed to analyse the operation parametric effect.

The dewatering of algal culture requires coagulation of the algal cells. However, the coagulation in a continuous operation is slowed down through the excretion of Soluble Algal Products (SAPs). Electrocoagulation (EC), already utilized as a coagulation technique, has been investigated for its effects on SAPs characterizations. A mixed culture of Chlorella vulgaris, Scenedesmus Obliquus, Botryococcus braunii, Botryococcus sudeticus, and Afrocarpus falcatus was prepared and SAPs characteristics, including Specific Ultra Violet Absorbance (SUVA), Zeta potential, Molecular Weight (MW) fractionation, Dissolved Organic Carbon (DOC), protein and carbohydrate content, Excitation-Emission Matrix, and hydrophobicity using XAD resins, were measured and evaluated before and after electrocoagulation using mild steel and aluminum electrodes at 5 and 10 min. The results showed several improvements after EC. According to results, EC can render SAPs hydrophobicity up to 95 %, and the fluorescence peak results showed the complete removal of humic-like. Moreover, the SAPs were removed up to 21, 60, and 47 % for protein, carbohydrate and DOC, respectively. Results collectively showed that electrocoagulation might be able to mitigate the negative effects of growth on flocculation.

For further applications of microalgae such as bio-products, microalgal harvesting from its culture medium (e.g. wastewater) must be studied. This becomes more essential when investigating whether or not cells can stay viable to be recycled into the system. Microalgae culture, wastewater, and a mixture of both were separately electrocoagulated at wastewater Chemical Oxygen Demand ranging 66–2700 mg.l-1 and biomass dry weights between 1 and 8 g.l-1. The mixed culture contained species of C. Vulgaris, S. Obliquus, B. Braunii, B. Sudeticus, and A. Falcatus, since mixed culture technique can reduce the expenses in industrial scales by eliminating the costly sterilization strategies necessary to avoid contamination. The mixed samples were successfully separated with the efficiencies between 44-87% and 70–80% at different Chemical Oxygen Demand and biomass dry weights, respectively. In addition, it was shown that growth elements of carbon and nitrogen, although at lower rates, were consumed confirming the viability of the cells after electrocoagulation. The consumption rates for electrocoagulated samples were smaller than non-electrocoagulated samples only by 16, 12, and 31% in carbon, nitrate and ammonium concentrations, respectively. According to the obtained results electrical separation of microalgae could effectively harvest microalgae from wastewater without affecting the viability of the biomass.