1. The root cause of the pollution of uf filter membrane

Uf filter membrane pollution refers to the solution of the concentration of particles, colloidal solutions, organics, bacteria and other biological macromolecules in the liquid and the physical and equipment effects of the membrane, which leads to adsorption and deposition on the membrane surface or membrane pores, which reduces or blocks the membrane pores. This causes the membrane's water permeability or separation ability to decrease. Membrane fouling includes the cover fouling caused by the adsorption of too much interception on the membrane surface and the inner wall of the microplate pores, and the clogging of the membrane pores by the concentration of colloidal solution, organic matter, bacteria and other biological macromolecular substances.

(1). The surface of uf filter membrane is relatively thick (about 1cm), and the pore diameter is between 0.005-0.01um. The pollution layer on the surface of the membrane is probably a double-layer structure, the top layer is a loose layer of large particles, and a fine layer of small particles is close to the surface of the membrane. Due to the existence of the pollution layer, a large number of membranes are covered. In addition, the long-term interaction between the amount and concentration of biological macromolecular substances such as organic matter and bacteria and their residues can easily form agglomerates on the surface of the membrane and prevent the passage of water.

(2). The pore size of ro uf membrane is blocked by the amount and concentration of biological macromolecules such as colloidal solution, organic matter, bacteria, or the pore size of ro uf membrane becomes smaller or completely blocked due to the deposition of impurities such as adsorbed proteins. Pollution chemicals include colloidal solutions, organic matter, edible fungi and their calcium and iron carbonate scales. When water resources containing such polluting chemicals are cut off by the ultrafiltration membrane, many pollutants are cut off by the membrane and accumulated on the surface of the membrane. Long-term continuous operation, the particles cut off by the membrane can easily produce a suspicious glue layer and block the safe passage of water flow.

2.The basic principle of whether uf filter membrane needs to be cleaned

(1). According to the changes in the pressure drop at the inlet and outlet of ultrafiltration filter, in most cases, when the gas pressure exceeds the initial value of 0.05 MPa, it indicates that the frictional resistance of the liquid has been significantly expanded. As a daily management method, a large flow cleaning method in the adiabatic process can be selected for cleaning. If it fails, organic chemical cleaning methods can be used;
(2). According to the change of water permeability or water permeability quality, when the passage water volume or water permeability quality of the ultrafiltration system drops to an unacceptable level, it indicates that the flow channel is blocked, or the concentration value is polarized, which affects the separation characteristics of the membrane. . In this case, most of the cleaning methods that are closely combined with physical-organic chemistry are used, that is, physical methods are used to quickly clean a large number of polluting chemical substances, and then organic chemical methods are used to clean, saving chemical substances.

(3). Clean on time. The ultrafiltration system in operation can be cleaned regularly according to the law of membrane fouling. Can be cleaned manually. For large and medium-sized industrial production equipment, the time should be set in sequence according to the automatic control system to be cleaned on time.