Advanced treatment, membrane technology (MBR)
Membrane technologies are based on these elements’ ability to reject pollutants and allow water flow. They are categorized into dense membranes (formed by polymers) and porous membranes (formed by polymers and inorganic materials).
When it comes to dense membranes, separation (reverse osmosis and electrodialysis) is based on physical-chemical interactions between the permeable components and the membrane’s material. Dense membranes generally produce separation processes with a greater selectivity.
Porous membranes (ultrafiltration [UF] and microfiltration) achieve separation mechanically (through screening). Membrane bioreactors (MBR) combine biological processes of activated sludges with membrane filtration, and replace biomass separation of settlers with high efficiency membranes separation. This membrane separation causes a higher concentration of bacteria within the reactor, requiring a smaller volume and producing higher quality outlet water that generally can be directly reused.