A system, method and process for disinfection of internal surfaces in aseptic tanks and pipelines by flooding with sanitizing fog in facilities designed to store liquids in general, the system having an external equipment with means to generate sanitizing fog, controlling means of gases flow rate, in-line detectors and draining means of gases inside the tank, input means of fog carrying means comprising inert gases. A disinfection process includes introduction of a sanitizing fog with droplets having a maximum size of 10 μm, and 5 μm in some embodiments, simultaneously with removal of gases enclosed inside the tanks and pipelines, maintaining a positive pressure inside the tanks and pipelines. The method providing reduction of oxygen concentration inside the tanks in two steps, the first step having reduction to near 10% and the second a reduction to a value below 1%, filling the tank with a sanitizing fog during the second step.
