In each experiment, the feed was transferred to the high pressure pump and delivered to the membrane at 86 psig and 25 °C. Membrane Output flows which include the permeate and concentrate flows were returned back to the feed tank. Every 2 h, the parameters for evaluation of RO membranes performance and its fouling were measured. These parameters were electrical conductivity and temperature of the feed, permeate and concentrate streams, volumetric flow rate of permeate and concentrate, and transmembrane pressure drop. Also, for studying the type and amount of CaCO3 fouling on the RO membrane, scanning electron microscopy (SEM) was used. Temperature variations during experiments was nearly identical although in the presence of electromagnetic field the membrane outflows temperature was slightly (about 1–2 °C) above than that for the system without an electromagnetic field, though this difference was negligible. Temperature changes are shown in Fig. 3.