Are Membrane Bioreactors Ready for Widespread Application?

There’s a lot to admire about membrane bioreactors (MBRs). This emerging wastewater-treatment technology combines a suspended growth biomass, similar to those used in the traditional activated sludge process, with a membrane system that replaces gravity sedimentation and that retains biomass and clarifies effluent. MBRs offer a host of technical advantages over activated sludge systems, such as small size, and seem to be well suited for applications such as water reuse. In April 2003, the authors were part of a Rockefeller Foundation-sponsored team residency in Bellagio, Italy, that explored the potential of MBRs for sustainable, decentralized sanitation. In this paper we describe our approach to assessing technical readiness. We also report on whether MBR technology is ready for more widespread application in developed and developing countries. Because developed nations are already adopting MBRs for certain applications, the key issue is their readiness for a wider range of uses. This sets the stage for adoption to be considered in developing countries, because developed and developing nations share many technical issues. However, the opportunities for MBR technology differ, in part because the technical infrastructure and social settings vary.