In order to ensure a stable and reliable operation of municipal MBR plants, an enhanced mechanical pretreatment of the raw wastewater is essential. Removal of hair, fibrous material and other contraries which can lead to operational problems at the membrane modules is of particular importance. As the number of full scale applications is continuously increasing, now appropriate investigations can be carried out to determine the removal efficiency of different units (screens, sieves') or different combination of units (multi staged. system). First results of such investigations on two German MBR plants were already presented [F.-B. Frechen, W. Schier and M. Wett, Water Practice & Technology, Vol. 1, No. 3, IWA Publishing, 2006, doi: 10.2166/WPT.2006057.]. In 2006, DESEE executed further investigations on another three wwtps in The Netherlands, UK and Germany. This paper summarizes the results, thus updates the information available, discusses the present findings and gives an outlook on future developments.