Moving bed biofilm reactors (MBBR)

The Moving-Bed Biofilm Reactor (MBBR) is a moving bed plant, leading to the activated sludge biological clearing. These plants, defined biomass reactors, are different from suspended traditional systems: in fact the activated sludge within the reaction, oxidation/nitrification section, is not suspended in the water to be treated, but adheres to a series of plastic material carriers, exhibiting a high specific surface protection, when suspended and mobile inside the bioreactor. Such carriers are in plastics, whose density is similar to the water density, and they are suspended through the air inflow from the vessel bottom through lowers.

There are two MBBR systems:

MBBR only with the biomass adhesion

The total activated sludge present in the reactors are entirely attracted to the biocarriers. It is possible to treat extremely high sludge concentrations, thus disposing consistently high biomass quantities in the small volume of the bioreactor.

MBBR with an hybrid operation.

Inside the reactors there are two types of sludge: culture suspensions and biomass adhesions. The hybrid MBBRs are more flexible as they profit from the main features of the two types of sludge able to differentiate from pollutant removal and reaction kinetics according to the inlet waste. However sludge concentrations inside the reactor are lower than in the units with biomass adhesion only. A partial recycle from the activated sludge secondary sedimentation vessel in suspension is forecast, thus non adhering to the carriers.


MBBR are suitable in case of widening of existing treatment plants, with activated sludge, old-fashioned or undersized after an increase of the waste inlet. MBBR units are suitable for the domestic and industrial waste treatments, from AGRICULTURE AND FOOD INDUSTRY (dairy sector, meat processing, wine processing, good canning industry, confectionery, livestock breeding companies), TEXTILE INDUSTRY, TANNING INDUSTRY, CHEMICAL INDUSTRY AND PHARMACEUTICAL INDUSTRY.

Main MBBR benefits:
  • Possibility to widen existing plants, with a limited intervention on the wall structures;
  • Reduced oxidation section;
  • High reaction and pollutant removal kinetics;
  • Simple installation and management: it is possible to change the filling waste quantity and therefore the sludge concentration in the vessel.

STA offers MBBR customised systems, but a wide range of prefab units systems are available as well sized according to the specific pollutant load, in a traditional concrete structure or profiting from the latest up-to-date solutions available on the market with structured plastics (PE, PRFV, etc) and steel as well.