The filtering mechanism of the filter cloth filter mainly includes:

(1) Mechanical filtration. The filter material layer is composed of filter material particles of different sizes. The pores between the filter particles are like a sieve. When wastewater flows through the filter layer, suspended particles with larger pore sizes will be trapped in the pores and separated from the water. Throughout the filtration process, the pores between the particles of the filter material are getting smaller and smaller, which also has a filtering effect on fine suspended matter.

(2) Adsorption and contact coagulation. The filter material has a large surface area and strong adsorption capacity. As the wastewater passes through the filter bed, it passes through the winding waterways. There is a lot of contact between the suspended particles and the filter. During the contact process, due to the intermolecular interaction, adsorption and contact coagulation are prone to occur, especially when the flocculant is added before filtration, the contact coagulation phenomenon is more prominent. The smaller the filter particles, the better the adsorption and contact coagulation effects.

(3) Precipitation. Each pore in the filter layer acts as a shallow sedimentation tank. When the wastewater flows through, some suspended particles in the wastewater will be deposited on the surface of the filter particles.

Filtration process of filter cloth filter: When the wastewater enters the filter, larger suspended particles are trapped, and the finer suspended particles are trapped by the contact filter particles or the attached suspended particles, resulting in adsorption and contact coagulation. Some incompletely trapped materials flow into the next layer of filter material under the action of water flow; or due to excessive adsorption on the surface of the filter material particles, the pore diameter becomes smaller and the flow rate increases, and the intercepted material will also enter the next under the erosion of water Layer filter. T stream. Therefore, as the filtration time is extended, more substances are trapped deep in the filter layer. Even if the filter comes out, the water quality will deteriorate. Because the filtering mechanism of the filter with a small particle size of the upper filter material mainly includes: high contact condensation and adsorption efficiency, and a certain mechanical retention effect, most of the suspended matter is trapped in the filter layer with a small particle size of the filter material. surface. The suspended matter in the lower layer is less, and the suspended matter in the filter layer is unevenly distributed. The ability of filter media to trap suspended matter can be expressed by its ability to trap sewage. The interception capacity refers to the mass of pollutants trapped by the filter per unit volume or mass in each working cycle, and the unit is kilograms per cubic meter (kg / m3).