Operating Principle and Maintenance of MBR Flat Sheet Membrane Filtration

MBR membrane filtration principle

MBR flat sheet membrane physical filtration principle

MBR flat sheet membrane is immersed in wastewater, and the wastewater flows between two flat sheet membranes. Clean water flows into the filter plate of the flat sheet membrane through pressure or external suction, and then flows out to the collection pool through the water outlet of the flat sheet membrane, achieving solid-liquid separation.

The sludge accumulated on the membrane surface is separated from the MBR flat sheet membrane surface due to the shear force of the air bubbles, thus ensuring the continuous solid-liquid separation capacity of the membrane.

MBR flat sheet membrane biological filtration principle

In addition to the physical filtration principle of ordinary membranes, a layer of dense biofilm grows uniformly outside the thin film layer of the flat sheet membrane during actual operation, which contributes greatly to solid-liquid separation.

Most solid particles are actually intercepted by this layer of biofilm, and the filtering of the biofilm greatly slows down the pollution rate of the MBR physical flat sheet membrane. The MBR flat sheet membrane can run for several months without cleaning, mainly due to the presence of the biofilm.

Knowledge of MBR flat sheet membrane operation and maintenance for wastewater treatment

As an efficient and low-pollution purification technology that integrates separation and concentration, MBR flat sheet membrane separation technology has the characteristics of simple operation, convenient maintenance, low energy consumption, and strong adaptability, and has gradually been recognized and applied by environmental protection workers and those concerned with the environment. Although the initial MBR membrane price can be higher than other technologies, it delivers significant savings in the long run, providing an affordable solution for wastewater treatment. 

Daily inspection

In order to ensure the stable operation of the MBR flat sheet membrane components, the aeration state of the MBR flat sheet membrane and the stability of the biological treatment are particularly important, and the following daily inspections need to be carried out.

Transmembrane pressure difference: Check the stability of transmembrane pressure difference. A sudden increase in transmembrane pressure difference indicates membrane blockage, which may be caused by abnormal aeration status or deterioration of sludge properties.

In this case, check the following parameters and take necessary actions, such as chemical cleaning of the membrane component. If you are not familiar with it, ask the disinfectant products manufacturer for more information.

Aeration status: Check if the aeration air volume of the MBR flat sheet membrane is the standard volume and if it is evenly aerated. If abnormal aeration air volume or obvious uneven aeration is found, necessary measures should be taken.

For example, remove the scaling of the MBR flat sheet membrane aeration pipe, check the installation status, check the blower, and adjust the aeration.

Membrane cleaning

The cleaning of the MBR flat sheet membrane is an online flushing, which means that the membrane component does not need to be removed from the membrane pool, and it can be cleaned directly in the membrane pool. Generally, sodium hypochlorite (at a concentration of 0.5%) or oxalic acid (at a concentration of 0.5%) are used to clean the MBR flat sheet membrane.

Before cleaning, first turn off the suction pump and blower, and let the medicine flow into the membrane plate through the medicine inlet installed on the upper part of the MBR flat sheet membrane component, and the amount of medicine injected should be controlled according to the operation manual.

Generally, the amount of each drug used for cleaning each membrane is about 3L/5L. After injecting the medicine, soak it for about 1-3 hours, and then drain the medicine with a suction pump. If necessary, confirm and re-inject hydrochloric acid or an equivalent drug, soak it for about 1-3 hours, and then drain the medicine with a suction pump. The entire cleaning process will last for 4-5 hours, and the MBR flat sheet membrane will resume its membrane flux after cleaning.