The rate of oxygen delivery determines, in many cases, the efficiency of aerobic processes used in wastewater treatment. In this work, a plunging jet loop system with a perforated downcomer was designed and operated to study oxygen transfer rate in aqueous solutions of glucose (1-4 wt.%) and a low foam surfactant (0.037-0.074 wt.%). At normal temperature and pressure, K(L)a decreases with increasing the weight percent of glucose while it increases with increasing the surfactant concentration. Simultaneous presence of glucose and surfactant in water was found to result in intermediate values of K(L)a.