A Membrane Bioreactor (MBR) is the combination of a membrane process, usually based on Ultrafiltration membranes, with a biological wastewater treatment process, the activated sludge process. MBRs are nowadays widely used for municipal and industrial wastewater treatment.

When used with domestic wastewater, MBR processes can produce effluent of high quality enough to be discharged to coastal, surface or brackish waterways or to be reclaimed for urban irrigation. Other advantages of MBRs over conventional processes include small footprint, easy retrofit and upgrade of old wastewater treatment plants.

Two MBR configurations exist: internal/submerged, where the membranes are immersed in and integral to the biological reactor; and external/sidestream, where membranes are a separate unit process requiring an intermediate pumping step.

De.mem offers MBRs for a wide range of applications. A common design by De.mem is based on the so-called “Ludzack-Ettinger MLE process” with MBR polishing and disinfection typically using liquid chlorine to achieve the required pathogen log reduction and produce Class A effluent.