Mixing intensity, gas hold-up and volumetric mass transfer coefficient of various multiple-impeller configurations are measured in a vessel of inner diameter 0.29 m equipped with three impellers on a common shaft. Five types of impellers are used. Distilled water with 3 vol.% Sokrat 44 is used as a liquid phase with Newtonian behaviour and viscosity 12.9 mPa.s. Air is used as gas phase. Mixing intensity was measured using tracer experiment and Dynamic Pressure Method was used for the measurement of volumetric mass transfer coefficient. Transport characteristics are presented for individual impeller configurations as functions of power consumption and superficial gas velocity. The impellers are compared each other and with transport characteristics for non-viscous solutions measured previously