Membrane Bio-Reactor - MBR

MEMBRIGHT® is F.L.I. Brightwater's Membrane Bio Reactor (MBR) system, designed to achieve high quality effluent within a small overall foot print. The MBR process utilises the well proven activated sludge process, but replaces conventional final settlement with an ultrafine membrane which effectively filters the final effluent.  

MBR Membrane Tanks1

  MBR Membrane Plant2

Benefits of MEMBRIGHT® MBR
- The membrane is an extremely effective solids separation device.
High removal efficiency results in a very high effluent quality (2/2/0.5mg/l or better).
Simplicity of system design.
Reactor volume is greatly reduced when compared with an activated sludge plant basin due to the fact that MEMBRIGHT
® runs at active MLSS values up to 15,000 mg/l, compared with typical values for conventional activated plants of 3000 to 5000 mg/l.
No requirement for final settlement tanks.
Offers bacterial removal without the need for complicated ultra violet radiation systems.
Water re-use applications.

MEMBRIGHT® Membrane Bio Reactor General Description

Membrane Bio Reactors provide a very compact, robust, simple sewage treatment plants that are capable of producing very high quality effluents.

Various proprietary designs are available, but the F.L.I. Brightwater MEMBRIGHT® system has been developed to include a number of process and engineering advances that make for simple and reliable plants that are economical to operate.

Through continuous extensive research F.L.I. Brightwater has developed its own membrane plate and frame system – designed and fabricated in the UK. We do not, thus, have the same supplier constraints / agreements as other UK membrane bioreactor system builders - using membranes plates from further afield.  

The MEMBRIGHT® MBR system uses a flat plate membrane comprising of a composite rigid support and a proven membrane material. The combination has a good chemical resistance and is hydrophilic. This rigid membrane plate provides the interface across which solid / liquid separation, and hence filtration, occurs. The membrane material used has a nominal pore size of 0.05 micron - a true ultrafiltration membrane which confers the twin benefits of improved filtration and prolongation of run times between cleans, rather than the pseudo – ultrafiltration adopted by other suppliers. Multiple membrane plates are assembled into modules for system simplicity and ease of operation, and one or more membrane modules are then placed in the membrane bioreactor tank(s).

                                Membrane Module

The effluent flow through the MEMBRIGHT® MBR is by gravity – a MEMBRIGHT® MBR system can either be fitted into an existing gravity sewage treatment works site or be gravity fed by providing one or more stages of a lift pumping where no system hydraulic head is available.


Inlet raw effluent would typically pass through screening, degreasing and degritting prior to flowing to a flow splitting device and into the membrane bioreactor tanks.

Flow splitting divides the incoming effluent equally between the number of membrane tanks in operation. Flow passes from the splitting device and into the MBR tanks under gravity.


The MBR tanks act in the same way as the traditional activated sludge tanks albeit with a solids / liquids separation occuring in it, and in this way the hydraulic and solids retention lose their previous relationship. The tanks are configured as “dead-end” aerated suspended growth bioreactors.


The filter membranes themselves are provided as part of a filter module assembly for ease of operation. A module comes as a complete assembly with a complement of membrane plates for the particular application, the aeration diffuser system, aeration feed pipework and treated effluent outlet pipework. The filter modules are fitted into the MBR tank and aeration / liquid pipework connected.

                                Membrane module Operating

In normal operation the membrane modules operate completely submerged in the MBR tanks and as the sewage passes across the membrane under hydraulic pressure head the filter membrane treats the effluent by retaining the biomass solids and allowing a filtered effluent to pass through for direct discharge. Final effluent leaving the MEMBRIGHT® MBR tanks normally requires no further treatment prior to discharge to the receptor / re-use.

One of the unique design features of the MEMBRIGHT® MBR system is that air required as part of the biological process is distributed in such a way that it simultaneously provides a scouring of the membrane surface - adding to the duration of membrane run times. Air is supplied to the membranes by blowers mounted externally, adjacent to the MBR tank and come complete with acoustic attenuators.

Refurbishment (re-skinning) of flat MBR Membrane Plates. FLI Brightwater also offers a service to re-skin, in the UK, plates from other flat plate membrane manufacturers.


Download the MEMBRIGHT® product literature


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