Results are presented on the hydrodynamics of a reactor for a single liquid-gas system (distilled water-air), fitted with a flow device without any rotating parts that has been termed TPJ (Two Perpendicular Jets) gas disperser. The device disperses gases in liquids using a novel technique. The behavior of the liquid-gas system in the reactor is described. The boundary is determined between two regions of the reactor, differing widely in hydrodynamic characteristics of the flow and the structure of the two phase mixture. Local values are evaluated of the Sauter bubble diameter close to the wall and inside the reactor. Moreover, independently for each of the two regions the following quantities are determined: Sauter bubble diameter, gas holdup, extended surface area, interfacial area and a statistical model of the bubble population. All these quantities are correlated with the flow rates of the gas and liquid phases. The TPJ technique can find a number of applications, especially in heterogeneous chemical and biochemical reactors, saturators, aerators used in environmental protection and in all cases where a vigorous contact is required between gas and liquid.