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MBR System FAQs & Solutions

2022-08-19

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:

FAQ	Reason	Solution
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