A novel approach for the intensification of ozonation of water and wastewater is presented using a highly efficient and compact multi-orifice oscillatory baffled column (MOBC) ozonation contactor. The MOBC uniquely yielded full (i.e. 100%) use of the ozone supplied with a very short (2.25 min) liquid contact time under continuous operation and reducing the need of further gas-liquid contacting equipment downstream from the MOBC. The increased performance of the MOBC ozonation reactor was benchmarked against a bubble column (BC) design and resulted in 20% increase on the rate of p-hydroxybenzoic acid (p-HBA) degradation, 75% increase in the rate of mineralisation of p-HBA per mole of ozone consumed, and 4.5-5.0-fold increase in the rate of mineralisation of p-HBA per mole of ozone supplied. This results from the very small size of bubbles (few hundreds of microns) and enhanced gas-liquid mass transfer and hold-up generated in the presence of small fluid pulsations and orifice baffles. (C) 2016 Elsevier B.V. All rights reserved.