Membrane bioreactors represent a promising technology for wastewater treatment, already applied to a wide variety of industrial effluents and sewage. Gas or air sparging is a commonly applied approach to generate surface shear to control fouling phenomena and cake formation causing flux reduction. In inside-out tubular membranes, gas sparging is usually applied to promote the development of a slug flow regime. Our present paper describes the development of a novel technique to study particle dynamics in tubular systems under slug flow regime. It combines the use of a laser beam generator to illuminate model particles, which are then motion pictured by means of a high speed camera. Digital video analysis is subsequently used to follow and study particle movements. The presented technique can be combined with other approaches such as CFD analysis in order to advance in the understanding of particle dynamics in tubular membrane systems. (C) 2010 Elsevier B.V. All rights reserved.