Abstract: Method of desalination and wastewater treatment in a microbial desalination cell reactor is provided, the microbial desalination cell reactor has three compartments, an anodic compartment, a cathodic compartment and a saline compartment, the method is carried out by (a) adding electrically conductive particles or electrically conductive material in the anodic compartment and cathodic compartment, (b) adding bacteria species of the genus Geobacter in the anodic compartment and several solutions in the compartments (c) replacing the solutions in the cathodic compartment and in the saline compartment and (d) oxidizing organic matter present in wastewater by bacteria from the genus Geobacter in the anodic compartment and desalinating the solution in the saline compartment and (e)after 20 to 30 operation cycles, replacing the solution in the saline compartment by a solution of hypochlorite salt.