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Filtration Process
Aug 10, 2017

Principle of filtration: Under the action of pressure difference, the liquid (or gas) in the suspension is trapped through the permeable medium (the filter medium) and the solid particles as the medium, Filter thus separating the liquid and the solid.

Filtration is a process of separating the solid particles suspended in a liquid or gas.

1) to achieve the two conditions of filtering:

① have the necessary equipment to achieve the separation process;

② filter on both sides to maintain a certain pressure difference (driving force).

2) commonly used filtration method can be divided into gravity filter, vacuum filtration, pressure filtration and centrifugal filtration several.

Filtration is the removal of liquid (or gas) through the media, solid particles and other substances in the suspension (or containing solid particles of hot gas) under the action of propulsion or other external forces by the filter medium so that the solids and other substances are mixed with the liquid Or gas). Filter There are many ways to filter, the use of the system is also very wide, solid - liquid, solid - gas, large particles, small particles are common.

Filter characteristics

1, high filtration efficiency: the removal rate of suspended solids in water up to 95% or more, macromolecular organic matter, viruses, bacteria, colloids, Filter iron and other impurities have a certain removal effect, after a good coagulation treatment of treated water, When the water is 10NTU, the water is below 1NTU;

2, the filtration speed: generally 40m / h, up to 60m / h, is more than 3 times the ordinary sand filter;

3, the amount of pollutants: generally 15 ~ 35kg / m3, is more than 4 times the ordinary sand filter;

4, backwash water consumption is low: backwash water consumption is less than the cycle of 1 ~ 2% of the amount of water;

5, low dosage, low operating costs: the filter bed structure and the characteristics of the filter itself, flocculant dosage is conventional technology 1/2 to 1/3. Cycle water production increased, Filter tons of water running costs also decreased;

6, covers an area of small: the same amount of water, the area occupied by ordinary sand filter 1/3 the following.

7, adjustable and strong. Filtration accuracy, interception capacity, filter resistance and other parameters can be adjusted according to need;

8, filter material durable, with a life of more than 20 years.


The flocculant is stirred by the pump impeller and then mixed with the fine solid particles in the raw water and the micro-flocculation reaction of the colloidal substance is carried out. Filter The flocculant is stirred by the pump impeller, Generating flocs larger than 5 microns in volume, flowing through the filtration system into the highly efficient asymmetric fiber filter, and the flocs are trapped by filter media.