How does reverse osmosis membrane biocide act on bacteria and biological sludge on the membrane surface?
Publish Time: 2025-06-05
In the field of water treatment, reverse osmosis (RO) technology is widely used to remove dissolved salts, organic matter and microorganisms in water. However, as the use time increases, a layer of biological sludge composed of bacteria and their metabolites often forms on the surface of the RO membrane, which not only reduces the permeation efficiency of the membrane, but may also cause system performance degradation or even failure. In order to deal with this problem, reverse osmosis membrane biocide came into being.Basic mechanism of action of bactericidesReverse osmosis membrane biocide mainly achieves bactericidal effects by interfering with the metabolism of bacteria or destroying their cell structure. First, many bactericides can penetrate the bacterial cell wall and react with key enzymes or proteins in the cell, thereby inhibiting the life activities of bacteria. For example, some oxidizing bactericides such as chlorine and hydrogen peroxide can destroy DNA or other important molecules inside bacterial cells through oxidation, leading to bacterial death. In addition, non-oxidizing bactericides may achieve similar effects by blocking the function of specific enzymes or changing the permeability of cell membranes.Mode of action against biological sludgeIn addition to directly killing bacteria, reverse osmosis membrane biocide is also effective against already formed biological sludge. Biological sludge is usually composed of living bacteria, dead bacteria and their secretions, forming a complex ecosystem. Bactericides can break down the connections between these substances and weaken the overall structure of biological sludge. Some types of bactericides contain specific chemical components that can specifically degrade polysaccharides, proteins and other main components of biofilms, making it easier for biological sludge to fall off the membrane surface and be carried away by water.Selection and application strategy of bactericidesSelecting a suitable reverse osmosis membrane biocide should not only consider its effectiveness against target microorganisms, but also pay attention to its safety and environmental impact on RO membrane materials. The ideal bactericide should be able to kill bacteria efficiently without damaging the physical and chemical properties of the membrane. In actual operation, regular dosing is often used to maintain the clean state of the system. The impact dosing method is one of the common methods, that is, applying a bactericide at a high concentration in a short period of time to quickly reduce the microbial load in the system; while the continuous low-dose dosing method is more suitable for long-term prevention purposes and maintains a relatively stable microbial level.Challenges and solutions in practiceAlthough reverse osmosis membrane biocide performs well in controlling microbial contamination, it still faces several challenges in actual application. On the one hand, the long-term use of a certain type of bactericide may induce bacterial resistance; on the other hand, the optimal bactericidal scheme required under different water quality conditions is also different. To solve these problems, experts recommend the use of multiple bactericides in rotation and the adjustment of dosing strategies according to specific working conditions. At the same time, strengthening water quality monitoring and timely grasping the dynamic changes of microorganisms are also key links in optimizing the bactericidal effect.In short, reverse osmosis membrane biocide effectively acts on bacteria and biological sludge on the membrane surface through various channels, ensuring the stable operation of the RO system. The correct selection and rational use of such chemicals can not only improve water treatment efficiency, but also extend the service life of equipment and reduce maintenance costs.
