The term MABR stands for “Membrane Aerated Biological Reactor”, and it defines a particular application of gas permeable membranes in the municipal wastewater treatment field based on the ability of organic biofilms to develop and grow on membranes that act at the same time as a support and device for the supply of the oxygen necessary for their reproduction, with a very low energy consumption and a high transfer efficiency.
In a MABR system, the driving force for the transfer of oxygen in the membrane is represented by its concentration gradient, rather than by the pressure. Consequently, the blowers responsible for supplying air to the membranes of the MABR process must only overcome the pressure drops caused by the length of the membranes and related pipes and instruments and can therefore operate at a low pressure with a very low energy consumption.
With this technology it is possible to obtain a very high Oxygen Transfer Efficiency (OTE), even within shallow tanks such as those of prefabricated solutions that can be adopted for small plants, for existing tanks used for aeration with surface turbines and for secondary clarifiers.
Another important feature of an MABR system is the biological process that occurs in these systems: oxygen and nutrients diffuse from two opposite sides within the biofilm that grows on the membranes. The oxygen is delivered to the membrane/biofilm interface, while the nutrients come from the wastewater/biofilm interface: this way it is possible to obtain simultaneous nitrification/denitrification processes, thanks to the development of the different colonies of microorganisms that are part of the biofilm at high biological specialization.