MBR/UF and MABR membranes

Ultrafiltration is a process that uses organic polymeric membranes to filter particles based on their size and it is typically used to separate or remove bacteria and macromolecules with a molecular weight greater than about 300,000 daltons from wastewater in both municipal and industrial applications. The configuration in which the membrane is used within a biological process is called MBR (Membrane BioReactor) which indicates the water purification process with activated sludge (BioReactor) in which the liquid-solid separation phase is carried out through a membrane filtration unit (the Membranes) instead of a secondary clarifier, that is the usual sludge separation stage adopted in conventional activated sludge plants. On the other hand, when membranes are  used as a polishing stage after a biological process, it is called TT (Tertiary Treatement), which is a process whose ultrafiltration aims to remove bacteria and macromolecules downstream in a secondary clarifier stage. Another possible application of polymeric membranes is in the production of drinking water from sea water/rivers/lakes etc. where ultrafiltration is introduced as a fundamental treatment to remove suspended solids and bacteria before sending the water to furthers polishing stages (activated carbon/UV) and to the distribution network.

Gas permeable membranes for biofilm aeration, on the other hand, are a recently introduced innovative technology often referred to as MABR (Membrane Aerated Biological Reactor). This technology is applied to the treatment of municipal wastewater which is based on the ability of bacterial biofilms to develop and grow on membranes that act both as a support for their growth and as a means through which the oxygen necessary for their reproduction is supplied.