Impeller submergence governs the performance of mixing tanks employed in chemical and biochemical operations. Present work experimentally investigates the effect of impeller submergence depths on power consumption when arrowhead impeller has been used in the process. Arrowhead impeller performs better than the conventional Rushton impeller. It has been found that at higher range of impeller submergence, mixing processes consume less power. Optimal range of submergence depth is 0.8 to 0.9 times the impeller diameter.