eramic Membrane Pollution and Cleaning Strategy

Ceramic membrane will produce pollution in the filtration process of various materials and liquids: concentration polarization, scaling pollution, gel polarization, solute adsorption, membrane pore blockage, microorganism and other pollution. The pollution of ceramic membrane cannot be completely avoided in the process of use. The optimization of operating parameters can only reduce pollution and improve filtration efficiency, so effective cleaning is the foundation to solve the stable operation of membrane.

1. Alkali cleaning: recycled alkali pre washing + alkali washing (alkali washing and sodium hypochlorite) + water washing + flux test;

2. Acid cleaning: acid cleaning + water cleaning + flux test;

3. Standard whole process cleaning: recycled alkali pre washing + alkali washing (alkali washing and sodium hypochlorite) + water washing + Acid Pre washing + acid washing + water washing + flux test;

4. Special cleaning agent: M430 (weak oxidation of solid), M120 (alkaline), M310 acidic.

Matters Needing Attention

1. Temperature difference change:

During the cleaning process, the temperature difference of the membrane module shall not exceed 25℃, or the temperature difference change shall be less than 10℃ per minute, otherwise, it is easy to cause cracks or fractures due to thermal shock of the membrane core;

2. Cleaning flux recovery:

If the membrane group is seriously polluted and the CIP cleaning solution is very dirty, another alkaline washing can be carried out. If the flux recovery is not good after alkaline washing, another pickling can be carried out;

3. After each feeding, it must be cleaned:

Membrane separation performance and membrane cleaning effect are the main factors to maintain the stable operation of the system. Therefore, it must be cleaned after each feeding. If it is not cleaned for a long time, the pollutants will scale on the membrane surface, grow bacteria and form a biofilm, which will damage the membrane layer and affect the service life of the membrane;

4. Keep the dirty film that has not been cleaned soaked:

The dirty membrane that has not been cleaned must not be dried out, otherwise the membrane flux may have irreparable attenuation; If this happens, during the cleaning process, the contaminated layer must be loosened by soaking in alkaline solution for a long time;

5. Sodium hypochlorite stock solution will react violently with nitric acid. It is suggested that the two transmission pipelines can be designed separately.