A device and method for the treatment of fluids using electrostatic fields generated by a high voltage electric current, which reduces or eliminates calcification, scaling and microbiological contamination. A high voltage negative DC current is applied to a core electrode, generating an electrostatic field which traverses a dielectric sleeve surrounding the core electrode and charges the exterior surface of the dielectric sleeve. Organic and inorganic particles as well as biological contaminants which pass through the electrostatic field or contact the surface of the dielectric sleeve are then charged. Fluid flowing through the device is agitated by a combination of spiral vane sections surrounding the dielectric sleeve and helical baffle sections lining the housing wall. Charged inorganic particles coalesce into spherical aggregates which resist adhesion to pipes and vessels and can be filtered by techniques such as RO without deteriorating the filter membrane. The device can thus be used to pre-treat water so as to enhance the performance and durability of purification systems such as RO filtration systems.