1. The pretreatment of the influent water body of uf membrane module
(1). Eliminate microorganisms
When the water contains microorganisms, after being added to the pretreatment system, some of the blocked microorganisms are likely to adhere to the pretreatment system. When it adheres to the surface of uf membrane module, it is likely to completely block the microwell plate, and even more serious problems will occur. Therefore, microbes such as bacteria and algae in raw water must be highly valued. In water treatment projects, oxidants such as NaClO and O3 are usually added, and the concentration is generally 1 to 5 mg/l. In addition, ultraviolet sterilization can also be applied. In the laboratory,hollow fiber uf membrane can be recycled through hydrogen peroxide (H2O2) or potassium permanganate aqueous solution for 30-60 minutes. The microbe-killing treatment can only kill microbes, but it cannot remove microbes from the water, and can only prevent microbes from multiplying.
(2). Reduce influent turbidity
When the water contains suspended solids, colloidal solutions, microorganisms and other residues, it will cause the water to become turbid to a certain extent. This turbidity will block light from passing through. This photoelectric phenomenon is related to the number, size and appearance of impurities. The turbidity of water is generally measured by corrosion degree. The turbidity formed by 1mg/l SiO2 is required to be 1 degree. The greater the degree, the greater the impurity content. Different industries have different regulations on the turbidity of water supply, and the turbidity of drinking water shall not exceed 5 degrees.
2. Adjustment requirements for the inlet water body of uf membrane module
(1) Temperature requirements
The calibrated water permeation rate of uf membrane module is generally tested with pure water at 25°C. The permeation rate of ro uf membrane is positively related to the temperature, and the temperature index is about 0.02/1°C, that is, for every 1°C increase in temperature, the permeation rate increases by about 2.0%. Therefore, when the temperature of the water supply is low (for example, less than 5°C), a certain heating method can be selected to run at a higher temperature to improve the working capacity. However, when the temperature is too high, it is not good for uf membrane module, which will cause the membrane function to change. For this matter, you can choose a cooling method to reduce the temperature of the water supply.
(2) PH value requirements
Ro uf membrane made of different raw materials has different fusion ranges for PH value. For example, cellulose ester is suitable for PH=4~6, PAN, PVDF and other membranes. It can be used in the range of PH=2~12. The scope of application must be adjusted. At present, the commonly used PH regulators mainly include acids (HCl and H2SO4), etc. and alkalis (NaOH, etc.).