A membrane bioreactor (MBR) is a technology used in wastewater treatment where a biological process is combined with membrane filtration. The biological process involves microorganisms breaking down organic matter in the wastewater, while the membrane filtration process removes solids and pathogens from the treated water. MBRs are becoming increasingly popular for wastewater treatment due to their efficiency in producing high-quality treated water and their compact design. They are used in various applications, including municipal wastewater treatment plants, industrial wastewater treatment, and decentralized wastewater treatment systems.