This paper investigates the feasibility of recovering waste energy from typical bio-gas upgrading facilities by means of a hydraulic turbine, and presents analysis of different types of hydraulic power recovery turbines. A selection method and analysis is developed which can be applied to an existing process to determine the effectiveness and energy savings of such a system for its economic viability. A practical testing rig was designed and constructed to verify the reliability and consistency of data for the both selection and optimization techniques. It was found that a centrifugal pump operating in reverse flow, essentially as a turbine, could be a possible option for waste energy recovery. (C) 2009 Elsevier Ltd. All rights reserved.