A moving bed biofilm reactor (MBBR) is a type of wastewater treatment technology that uses small plastic carriers, or media, to support the growth of microorganisms. These microorganisms form a biofilm on the media, which helps break down organic pollutants in the water. The media is kept in constant motion, allowing for better contact between the biofilm and the wastewater, enhancing the treatment process. MBBRs are often used in municipal and industrial wastewater treatment facilities due to their efficiency and compact design. They can handle varying flow rates and are effective in removing nutrients like nitrogen and phosphorus. This technology is part of the broader field of biological wastewater treatment.