Moving Bed Bio-Reactor (MBBR) is the latest technology to emerge in the treatment of municipal and industrial wastewater. Encompassing the benefits of activated sludge and fixed-film technologies without any of the downsides, MBBR technology offers the ideal solution in BOD & COD removal, as well as nitrification.


The MBBR system consists of an aeration tank similar to that of an activated sludge tank. Plastic carriers (media) within the MBBR encourage the biological breakdown of substrate in the influent wastewater. The media provide a protected surface area for aerobic and anaerobic bacterial communities, known as biofilm, to thrive. This additional surface area and the mixing of carriers due to the aeration system increases the contact between the biofilm and nutrients within wastewater, leading to higher levels of degradation and therefore increased productivity by the MBBR.

MBBR technology is self-maintaining, optimising levels of biofilm in response to influent wastewater. The biofilm responds to load fluctuations automatically, making MBBR an ideal solution for overloaded wastewater treatment plants. As populations numbers increase in municipalities, MBBR is a cost effective and high efficiency alternative to the building of new treatment plants. Typically, only one feed pump is supplied as part of the MBBR package, but a second pump can be supplied on request. 10mtrs of inlet, outlet and de-sludge hose come as standard.​

Advanced Solutions and Technologies Ltd can offer new or retro-fit MBBR plants into various types of existing treatment plants.  Please see our Aghagallon Case Study for one such example.


  • Retrofit existing fixed film plants and increase there capacity by an average of 35% without changing blowers
  • Removal of Ammonia (NH3) in tertiary treatment mode
  • Roughing filter in carbonaceous (BOD) treatment mode
  • Mobile emergency response unit
  • The MBBR system can be easily configured to deal with Total Nitrogen
  • Retrofits are a cost effective way of utilising the existing structure and sweating the assets to gain value for money and use

Key Advantages of MBBR

Small Footprint

High Performance

Cost Effective

Ease of Operation

High Loading Rate

Single Pass Treatment

Resilient to Toxic Shock

No Desludging

Flexible Modular Design

No Mechanical Parts

No Blocking Tendency

Minimal Operator Involvment


Expertly designed for use within a MBBR, the media used by AS & Tech is high-density polyethylene (HDPE). The carriers are injection moulded, ensuring each carrier is identical. Designed to be compact in size, the carriers offer in excess of 600 m2/m3 of surface area for breakdown of the biomass. With a specific gravity of 0.95g/cm3, as the biofilm builds up on the media it leads to neutral buoyancy. Uniformly distributed medium bubble diffusers placed along the bottom of the tank and the gravity of the media ensure mixing throughout the system.

To prevent the HDPE carriers from escaping from each cell, a simple screen (see photos) placed on the outlet of each cell within the MBBR prevents any media carry-over from occurring.

Advantages & Applications of MBBR

Considered a biofilm process, the MBBR system is becoming increasingly popular across Europe for wastewater solutions. Like traditional biofilm processes, including the Submerged Aerated Filter (SAF), Trickling filter, Rotating Biological Contactor (RBC) and the Biological Aerated Filter (BAF), less space is required than activated sludge systems due to the higher concentration of the biomass.

Whilst most traditional biofilm processes experience clogging and build of head-loss, the MBBR technology incorporates floating carriers meaning the system is not liable to suffer the same disadvantages.

MBBR systems do not require a sludge recirculation line, which is the case for activated sludge systems. The MBBR does need to be de-sludged, but very infrequently, as most residual solids are carried over into the final settling tanks. The unit comes complete with desludge lines to aid both the desludge and drain down (if moving the unit to a new site) process.

MBBR is often installed as a retro-fit to an existing activated sludge plant, to increase the capacity of the system. The degree of filling of carriers can be adapted to the specific situation. Retro-fits cater for an existing treatment plant to increase its capacity without increasing the footprint by constructing new tanks.

The mobile MBBR unit is small enough for easy transport between treatment sites. It can be used as a temporary unit whilst remediation works are carried out on site, or installed as the best solution on small to medium sites. Units can be purchased outright or hired (subject to availability).

The MBBR can be operated in both carbonaceous and tertiary mode. Once the favoured bacteria are established within the unit for carbonaceous or tertiary, the MBBR can easily deal with BOD removal as well as the removal of ammonia via nitrification.

Performance Capability

The AS750 MBBR unit consists of 4 off treatment cells, each cell is 1.5metre x 1.5 metre square. In tertiary mode, the mobile AS750 MBBR unit can reduce ammonia (NH3) levels by up to 90% (based on primary settled domestic sewage) when operated at the optimal flow rate of 3.5l/s. Whilst operating in tertiary mode, the mobile MBBR achieves a 50% reduction in BOD without any settlement. When settlement does occur, there is typically a 70% reduction in levels of BOD in the effluent. When running in carboneous mode the flow rate through the AS750 MBBR can be increased to 6.0l/s based on a typical discharge consent of 20:30.

Design & Energy Saving Features

A separate kiosk for the MBBR comes as standard, which contains the control panel as well as 2 duty/standby blowers. For the 750 P.E. MBBR unit, each blower is 4kW and powered by invertors. This reduction in blower size ensures savings on both operational and capital costs for the customer.

When constructing new MBBR systems, the filling degree can be adjusted after the build is completed. For example, an MBBR designed with 40% fill of media can later be increased to 70% of media. This could be in response to population increases for municipal wastewater treatment plant or increased wastewater production from an industrial factory.

Retrofitted MBBR’s usually require a downgrade in the size and/or speed of blowers. For example, a converted MBR plant upgraded to an MBBR plant can see energy saving costs of up to 50% compared to original running costs.

Our design features can be made bespoke to suit your needs.