The application of quartz sand filter material in multi-media filter has reached a very mature technology. The application of quartz sand filter material in water treatment industry at home and abroad is distributed in different departments such as chemical water workshop of power plant, water supply workshop of iron and steel plant, water truck workshop of fertilizer plant, sewage station of oilfield and so on.

Quartz sand filter is often used in water treatment. Its main material for water quality treatment is quartz sand. It intercepts and adsorbs sediment, colloid, metal ions and organic matter to achieve the purpose of sewage treatment. Many factories or enterprises do not know what problems to pay attention to when choosing quartz sand filters. The quartz sand filters used in quartz sand filters are described below.

1. Selection of Quartz Sand

Quartz sand filter material is the core of the whole filter. Quartz sand can be divided into different areas according to its size. The smaller the diameter, the better the effect of water purification. However, the filtering speed that flows through the quartz sand filter will decrease, so the size of quartz sand filter material is not the smaller the better, according to the quartz sand filter. Quartz sand filter material is selected according to the requirement of outflow velocity. When filling quartz sand, attention should be paid to filling in a certain order, quartz sand should be manufactured by regular manufacturers, so that the service life will be longer.

2. Flow rate of quartz sand filter

Quartz sand filter has strict requirements on the inlet and outlet water velocity of the equipment. If the flow velocity is too high, it may cause the filter material to roll over, and the effect of water purification is not good. In addition, there are certain restrictions on the backwashing speed of quartz sand filter. When the quality of filtered water does not meet the requirements, the whole equipment needs to be backwashed at this time to get out the pollutants adsorbed by the filter material. If the backwashing speed is too high, the filter material will flow out, which will lead to waste; if the speed is too high, it will lead to waste. Small, it can not clean the effect of filter material.

3. Supporting Layer of Quartz Sand Filter

The support layer of quartz sand filter exists, on the one hand, in order to hold the filter material and control it at a certain height, on the other hand, in order to prevent the filter material from being washed out when backwashing, so as to protect the filter material. Generally, the supporting layer is divided into two layers, the filling height of 1-2 mm is 150-200 mm, and the filling height of 2-3 mm is 150-200 mm.

4. Other filter media

In addition to quartz sand as filter material, activated carbon is also a good filter material, which also has a good ability to intercept pollutants. However, in actual water purification, activated carbon is not used much. On the one hand, activated carbon is relatively light, and it is easy to be washed out when backwashing; on the other hand, the price of activated carbon is much higher than quartz sand. Considering the operation cost, it is less economical than quartz sand.

5. Position of inlet and outlet of quartz sand filter

Quartz sand filter can be divided into top-down type and bottom-up type according to the different position of the inlet and outlet. Both of them can achieve good water treatment effect. Which way to choose should be combined with the actual situation, depending on the form required in advance design.

To select quartz sand filter, we must select products manufactured by regular manufacturers and ask for product qualification certificate, so that the quality of quartz sand filter is more assured. Installation of quartz sand filter should be carried out under the guidance of specialized technicians and by experienced teachers, so as to ensure the normal and reliable operation of the whole set of equipment.

Ministry of Construction Standards of the People's Republic of China

CJ 24.1-88

Quartz Sand Filter for Water Treatment

1 Scope of application

This standard is applicable to quartz sand filter material (or natural sand mainly containing silicon) and gravel carrier material (gravel used as carrier filter material in filters) for drinking water filtration. Quartz sand filter material and gravel support material for industrial water filtration can be executed by reference.

Technical Requirements for Quartz Sand Filter Material

2.1 The sum of fragmentation rate and wear rate of quartz sand filter material should not be 1.5% (the percentage is the same as below in terms of mass).

2.2 The density of quartz sand should not be less than 2.55g/cm3. Except for those with special requirements for density in use.

2.3 Quartz sand filter material should not contain visible clay, mica and organic impurities. The water leaching solution of filter material should not contain toxic substances, and the mud content should not exceed 1%. The content of light substances with density less than 2g/cm3 should not be greater than 0.2%.

The burning reduction of 2.4 quartz sand filter material should not exceed 0.7%.

The hydrochloric acid solubility of 2.5 quartz sand filter should not exceed 3.5%.

Particle size of 2.6 quartz sand filter

2.6.1 The size range of quartz sand in single or double filter media is generally 0.5-1.2 mm. The size range of quartz sand in three-layer filter is generally 0.5-0.8 mm.

2.6.2 Among the quartz sand filters with various particle sizes, the particle size smaller than the specified lower limit should not be greater than 3%, and the particle size larger than the specified upper limit should not be greater than 2%.

2.6.3 The effective particle size and coefficient of inhomogeneity of quartz sand filter material are determined by the user.

Technical Requirements for 3 Gravel Bearing Material

3.1 Most of the grains in gravel bearing materials should be close to spherical or equilateral bodies.

The density of 3.2 gravel bearing material should not be less than 2.5g/cm3.

3.3 Gravel bearing materials should not contain visible clay, shale and organic impurities, and water leaching wave of bearing materials should not contain toxic substances.

The mud content should not exceed 1%.

The hydrochloric acid solubility of 3.4 gravel bearing material should not exceed 5%.

Particle Size of 3.5 Gravel Bearing Material

3.5.1 The particle size range of gravel supporting materials used in single or double-layer filters is generally 2-4, 4-8, 8-16 and 16-3.