Membrane Bioreactor (MBR) as an Advanced Wastewater Treatment Technology

The development and application of a membrane bioreactor (MBR) for fullscale municipal wastewater treatment is the most important recent technological advance in terms of biological wastewater treatment. The MBR is a suspended growth-activated sludge system that utilizes microporous membranes for solid/liquid separation instead of secondary clarifiers. It represents a decisive step forward concerning effluent quality by 38 J. Radjenović et al. delivering a hygienically pure effluent and by exhibiting a very high operational reliability. Advanced MBR wastewater treatment technology is being successfully applied at an ever-increasing number of locations around the world. In this chapter, the authors have covered several aspects of MBR, with an exhaustive overview of its operational and biological performance. Different configurations and hydraulics of MBR are presented, with attention given to the fouling phenomenon and strategies for reducing it. Also, the high quality of MBR effluent is discussed, whereas in comparison with CAS removals of organic matter, ammonia, phosphorus, solids, bacteria and viruses are significantly enhanced. Emphasis has been given to the improved capability of MBR to remove organic contaminants present at trace concentration levels (ng L–1, μg L–1 and mgL–1), which to the authors’ knowledge represents a first attempt to summarize the published literature on this subject. Finally, advantages and disadvantages of MBR over CAS are concerned. In conclusion, MBR represents an efficient and costeffective process that copes excellently with the growing needs for transforming wastewater into clean water that can be returned to the hydrological cycle without detrimental effects.