MBR System FAQs & Solutions

Membrane bioreactor is a water treatment technology which combines membrane technology and biochemical reaction in sewage treatment. Membrane bioreactor (MBR) filters the sewage in biochemical reaction tank with membrane and separates sludge and water. On one hand, membrane intercepts the microorganisms in the reaction tank, which greatly increases the concentration of activated sludge in the tank to a high level, so that the biochemical reaction of wastewater degradation runs more rapidly and thoroughly. On the other hand, the water production is clean and clear due to high filtration precision of membrane.

In order to facilitate the operation and maintenance of MBR, solve problems in the process of operation timely, the common problems and solutions are summarized as bellow:




Rapid decrease of flux

Rapid increase of trans membrane pressure

Substandard influent quality

Pretreat and remove oil & grease, organicsolvent, polymeric flocculant, epoxy resins coating, dissolved matter of ion exchange resin, etc. in feeding water

Abnormal aeration system

Set reasonable aeration intensity and uniform air distribution (horizontal installation of membrane frame)

Excessive concentration of activated sludge

Check concentration of activated sludge and adjust it to normal level via technical control

Excessive membrane flux

Lower suction rate, decide reasonable flux by test

Output water quality deteriorates

Turbidity rises

Scratched by large particles in raw water

Add 2mm fine screen before membrane system

Damage when cleaning or scratched by small particles

Repair or replace membrane element

Connector leakage

Repair leaking point of membrane element connector

Membrane service life expiration

Replace membrane element

Aeration pipe is blocked

Uneven aeration

Unreasonable design of aeration pipeline

Downward holes of aeration pipe, pore size 3-4mm

Aeration pipeline is unused for long, sludge flows into aeration pipeline and block the pores

During system shutdown period, periodically start it for a while to keep the pipeline unblocked

Blower failure

Set check valve on pipeline to prevent sewage backflow to blower

Membrane frame is not horizontally installed

Membrane frame should be installed horizontally and keep aeration holes on same liquid level

Water production capacity does not reach the designed value

Low flux when start up new system

Improper pump selection, improper membrane pore selection, small membrane area, mismatching of pipeline, etc.

Membrane service life expiration or fouling

Replace or clean membrane modules

Low water temperature

Raise water temperature or add membrane element

Post time: Aug-19-2022