1. The root cause of the pollution of hollow fiber ultrafiltration membrane.

Hollow fiber ultrafiltration membrane pollution refers to the amount and concentration of biological macromolecular substances such as liquid particles, colloidal solutions, organic compounds, microbial strains, etc. to be treated, and the physical and mechanical equipment effects of the membrane, resulting in adsorption on the membrane surface or membrane pores, and deposition makes the membrane pores. Shrinkage or blockage, resulting in a decrease in the water permeability or separation working capacity of the membrane. The causes of membrane fouling include the coverage pollution caused by the absorption of excess interception on the membrane surface and the inner wall of the microplate hole, the situation of colloidal solution in the membrane hole, and the concentration of biological macromolecular substances such as organic compounds and microbial strains.

2. The criteria for whether hollow fiber ultrafiltration membrane must be cleaned

(1) According to the change of the pressure drop at the inlet and outlet of ultrafiltration filter, in most cases, when the gas pressure exceeds the default value of 0.05MPa, it means that the frictional resistance of the liquid has expanded significantly. As a daily management method, the isobaric and large flow flushing method can be used for flushing, and if it is ineffective, the organic chemical cleaning method can be used;
(2) According to the change of water permeability or water permeability quality, when the water permeability or water permeability quality of ultrafiltration filter is reduced to an unacceptable level, it means that the flow channel is blocked, or the separation performance of the membrane is affected by the polarization of the concentration value. damage. In this case, a combination of physical and organic chemistry methods can be used, that is, physical methods can quickly remove a large amount of contaminating chemicals, and then use organic chemical methods to save chemicals.

(3) Cleaning on time. Uf system water treatment in operation can be cleaned regularly or manually according to the regularity of membrane fouling. For large and medium-sized equipment in industrial production, it should be cleaned on time according to the sequence of the automatic control system.