Since 2006 Prof. Barjenbruch is Head of the Department of Urban Water Management at the TU Berlin. His main research topics: Wastewater and sludge treatment, water re-use, advanced wastewater treatment, rainwater management and rainwater treatment, energy optimisation and resource oriented sanitation.

He is  the vice president of the German Association for watermanagement wastewater and waste e. V. (DWA), and the Head of DWA-Group 8: „Processes of advanced waste water treatment „. Also he is a member of the International Water Association (IWA). From 1997 bis 2005 he worked as a senior engineer at the University of Rostock. Bevor he was head of the water department in a consultant company. In 1996 he made finished his PhD on the topic „Efficiency and economic of wastewater filtration“ at the University of Hannover.