Erratum to: Clean Techn Environ Policy (2008) 10:377–387 DOI 10.1007/s10098-008-0153-8

Page 381 of the original publication contains the following error:

Page # 381, Lines 17–20: “The fractional gas hold up (εg) in the tapered bubble column was determined by measuring the height of the aerated liquid (H) and that of the clear liquid without any aeration (H o).”

In this sentence “height” should be read as “volume”. Accordingly, H and H o would represent respective volumes rather than heights (Eq. 2 and in List of symbols).