Selection of pretreatment process for microbial membrane contamination

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Microbial contamination is a common challenge in water treatment systems. When microorganisms accumulate at the membrane water interface and form biofilms, they can seriously affect the performance of the membrane system. The problem of microbial contamination is particularly complex because microbes not only have some properties of colloidal substances, but also have a powerful ability to reproduce.

There are three main reasons for microbial contamination of membrane elements. First, membrane systems typically have a large membrane surface area, which provides more attachment points for microorganisms. Secondly, the filtration process of the membrane migrates microorganisms in the water to the membrane surface, further increasing the risk of contamination. Finally, flocculants, fungicides or scale inhibitors that may be used in the pretreatment process may also become nutrient sources for microorganisms if excessive, while the moist and dark environment inside the membrane components provides ideal conditions for microbial growth.

Selection of pretreatment process for microbial membrane contamination

In order to ensure the long-term stable operation of the membrane system, it is very important to prevent microbial contamination. Therefore, before the sewage enters the membrane system, it must be effectively sterilized. Reasonable sterilization treatment is the key factor to ensure the stable operation of the membrane system.

Selection of pretreatment process for microbial membrane contamination

Sterilization methods are usually divided into two categories: chemical sterilization and physical sterilization. Chemical sterilization is mainly achieved through the use of fungicides. The mode of action of these fungicides may be bactericidal or bacteriostatic. In sewage treatment, the commonly used fungicides include inorganic fungicides and organic fungicides. Inorganic fungicides are mainly oxidized, such as chlorine dioxide, liquid chlorine, ozone, etc., which have a strong oxidation capacity and can effectively kill microorganisms. Organic fungicides are mainly cationic quaternary ammonium salts, which destroy the normal physiological function of microorganisms by interacting with their cell membranes.

Selecting the right fungicide requires consideration of a number of factors, including the type of microorganism, the concentration, the water quality conditions, and the specific requirements of the treatment system. In addition, the dosage and frequency of use of fungicides also need to be strictly controlled to avoid environmental pollution and cost increase caused by excessive use.

In addition to chemical sterilization, physical sterilization methods such as ultraviolet irradiation, high temperature treatment, etc., also have certain application prospects. These methods do not require the addition of chemicals and are environmentally friendly, but may require higher equipment and operating costs.

To sum up, in order to effectively prevent microbial membrane pollution, it is necessary to carry out reasonable sterilization treatment before the sewage enters the membrane system. Selecting the appropriate bactericidal method and bactericide, and strictly controlling its use conditions, is the key to ensure the long-term stable operation of the membrane system.

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