Moving Bed Bioreactor Sewage Treatment Plants (MBBR)

The Moving Bed Biofilm Reactor (MBBR) is biological treatment technology commonly used sewage treatment plants
(STPs). It is designed to treat both industrial and municipal wastewater efficiently. The MBBR process combines the
advantages of suspended growth (activated sludge) and attached growth (biofilm) systems in a single reactor.
MBBR STP process:
 Biofilm Formation: In the MBBR system, microorganisms grow on small, free-floating plastic carriers
(media), which provide a large surface area for the biofilm to attach and develop.
 Moving Media: These plastic carriers are kept in continuous motion inside the reactor by aeration or
mechanical agitation, hence the term "moving bed." The movement helps prevent clogging and keeps the
biofilm in optimal conditions for biodegradation.
Steps in the MBBR Process:
 Raw wastewater enters the treatment system after undergoing pre-treatment to remove large solids, oils,
and fats. This is typically done using a screening or grit removal process.
 The pre-treated wastewater flows into the MBBR reactor, which is filled with plastic media. Here, the
microorganisms attached to the media consume organic pollutants and nutrients in the water.
 The biofilm grows on the surface of the moving media, and as the water flows through the reactor, pollutants
like BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), and nitrogen compounds are
removed through biological degradation.
 The movement of the carriers ensures that the biofilm is continually exposed to fresh wastewater and
prevents the system from clogging.
 The MBBR tank is followed by a secondary clarifier or sedimentation tank to separate the treated biofilm and
suspended solids from the effluent water.
 After biological treatment and solid separation, the treated water follows tertiary treatment such as Filtration,
chlorination or UV disinfection before being discharged or reused.