Volumetric mass transfer coefficient (kL(a)), is the critical transport characteristic in the design of mechanically agitated contactors. Prediction of k(L)a is nowadays mostly based on literature correlations. Our aim is to establish suitable k(L)a correlations for different types of devices that would be based on the experimental data set. In our previous work, the correlation for k(L)a prediction in coalescent batch were described only for Rushton turbines (Petricek et al., 2019). Now, we aim at the description of one universal correlation that would be viable for mechanically agitated contactors in coalescent batch for several impeller types with different diameters and their combinations on a common shaft. The measured transport characteristics were summarized into correlations. This correlation shape can be used to predict transport characteristics in industrial-scale vessels under a wide range of operational conditions. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.