When MBR membranes clog, various cleaning methods can be employed to restore their performance. These methods mainly consist of physical cleaning and chemical cleaning, each with its specific operational steps and precautions.
Physical Cleaning
Physical cleaning primarily involves removing impurities and contaminants from the surface of the film through physical means, without altering the chemical properties of the film material. Common physical cleaning methods include:
Online Air Cleaning：
EquipmentBlower
OperationBy injecting air into the membrane component using a blower, bubble disturbances are created on the membrane surface to remove adhered substances. The cleaning frequency can be set according to actual conditions, such as stopping water output after a certain period of operation (e.g., 8 minutes) and then conducting a 2-minute aeration cleaning.
Online Water Reverse Osmosis：
EquipmentReverse Suction Pump
OperationUtilizing a reverse osmosis pump, the cleaning solution (such as MBR effluent or tap water) is reversed through the membrane module to flush away pollutants on the membrane surface. The cleaning frequency is typically a one-minute backwash after working for a period (such as 29 minutes).
Ultrasonic Cleaning：
EquipmentUltrasonic Cleaning Machine
OperationDirectly contact the membrane component with the ultrasonic probe to remove stubborn contaminants from the membrane surface using the vibration effect of ultrasound. The cleaning time varies depending on the degree of contamination, typically ranging from a few minutes to half an hour.
Chemical Cleaning
Chemical cleaning involves the reaction of chemical agents with contaminants on the membrane surface to achieve the removal of pollutants. Common chemical cleaning methods include:
Online Chemical Cleaning：
Pharmaceuticals(NaClO), (HCl)
OperationChemical agents are fed back into the membrane module through a reverse flush pump, allowing the agents to thoroughly contact and react with the pollutants on the membrane surface. After cleaning, rinse thoroughly with clean water. The recommended cleaning frequency should be determined based on the degree of contamination of the membrane module, such as once a week or month.
Offline chemical cleaning：
OperationWhen online chemical cleaning is no longer sufficient, the membrane components must be removed from the system and immersed in a dedicated cleaning pool for soaking. The soaking time varies depending on the type of chemical and the degree of contamination, typically ranging from a few hours to several dozen hours. After cleaning, they must be thoroughly rinsed with clear water and reinstalled into the system.
Cautionary Notes
Cleaning CycleThe cleaning cycle should be determined based on the degree of contamination of the membrane components and the quality of the treated water, to prevent over-cleaning that may damage the membrane material.
Pharmaceutical ConcentrationWhen performing chemical cleaning, control the concentration and amount to prevent corrosion or damage to the membrane material.
Operational SafetyDuring the cleaning process, safety operation should be ensured, and protective gear such as gloves and masks should be worn to prevent direct contact of chemicals with the skin and eyes.
Cleaning Effectiveness EvaluationAfter cleaning, the cleaning effectiveness of the membrane components should be evaluated, such as checking the recovery of membrane flux and observing if there are any remaining contaminants on the membrane surface.
In summary, for MBR membrane clogging issues, appropriate cleaning methods can be chosen based on the specific situation. At the same time, it is essential to strengthen daily operation management and maintenance efforts to extend the lifespan of the membrane components and enhance treatment efficiency.
