Bubble columns are widely used for conducting gas-liquid and gas-liquid-solid mass transfer/chemical reactions. Sparger is the most important accessory because it decides the bubble size/rise velocity distribution. These, in turn, govern the radial and axial hold-up profiles, the liquid phase flow pattern and hence the performance of bubble columns. In particular, the sparger design is critical if the aspect ratio is low and the sparger design dominates the performance of the bubble column. However, systematic procedure for the selection of sparger design and type are not available in the published literature. This is the specific objective of the present work. In Part I, the performance of different spargers, including the newly developed wheel type of sparger is discussed. Thus the important considerations required for the sparger design are highlighted. The bubble column used in the manufacture of hydrogen peroxide has been considered as a case for illustration. (C) 2011 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.