What is Multi-media Filter Housings?

What is Multi-media Filter Housings?

The multi-media filter utilizes one or several filter media. Under a certain pressure, water with high turbidity passes through a certain thickness of granular or non-granular materials, thus effectively removing suspended impurities and clarifying the water. Commonly used filter media include quartz sand, anthracite, manganese sand, etc. It is mainly used for turbidity removal in water treatment, softening of water, pre-treatment of pure water, etc., and the turbidity of the effluent can be reduced to below 3 degrees. The meaning of filtration, in the water treatment process, filtration generally refers to the process in which filter media layers such as quartz sand and anthracite intercept suspended impurities in water, so as to clarify the water. The porous materials used for filtration are called filter media, and quartz sand is the most common filter medium. Filter media come in various forms such as granular, powdery and fibrous. Commonly used filter media include quartz sand, anthracite, activated carbon, magnetite, garnet, ceramics, plastic balls, etc. The multi-media filter (filter bed), that is, a media filter that uses more than two kinds of media as the filter layer. In the industrial circulating water treatment system, it is used to remove impurities and adsorb oil in the sewage, so that the water quality meets the requirements for cyclic use. The function of filtration is mainly to remove suspended or colloidal impurities in water, especially to effectively remove tiny particles and bacteria that cannot be removed by precipitation technology. There is also a certain degree of removal effect on BOD and COD, etc. I. Composition of the Filter The multi-media filter is mainly composed of the filter body, supporting pipelines and valves. Among them, the filter body mainly includes the following components: the cylinder body; the water distribution component; the support component; the backwashing air pipe; the filter media; the exhaust valve (external), etc. II. Selection Criteria of the Filter Media 1. It must have sufficient mechanical strength to avoid rapid wear and breakage during the backwashing process; 2. It should have good chemical stability; 3. It should not contain substances harmful to human health and toxic substances, nor should it contain substances harmful to production and affecting production; 4. In the selection of filter media, filter media with strong adsorption capacity, large dirt interception capacity, high water production and good effluent water quality should be preferably used. Among the filter media, pebbles mainly play a supporting role. In the filtration process, due to their high strength, the spacing gaps between them are stable, and the pores are large, which is convenient for the filtered water to pass through smoothly during the forward washing process; similarly, during the backwashing process, the backwashing water and backwashing air, etc. can pass through smoothly. In the conventional configuration, pebbles are divided into four specifications, and the paving method is from bottom to top, from large to small. III. Relationship between the Particle Size of the Filter Media and the Filling Height The ratio of the height of the filter bed to the average particle size of the filter media is 800 to 1000 (design specification). The particle size of the filter media is related to the filtration accuracy. IV. Multi-media Filters Common multi-media filters used in water treatment include: anthracite-quartz sand-magnetite filters, activated carbon-quartz sand-magnetite filters, activated carbon-quartz sand filters, quartz sand-ceramic filters, etc. In the design of the filter layer of the multi-media filter, the main factors to be considered are: 1. Different filter media have a large density difference to ensure that there will be no mixing layer phenomenon after the backwashing disturbance. 2. Select the filter media according to the purpose of the produced water. 3. The particle size requires that the particle size of the lower filter media is smaller than that of the upper filter media to ensure the effectiveness and full utilization of the lower filter media. In fact, taking the three-layer filter bed as an example, the particle size of the upper filter media is the largest, and it is composed of light filter media with a small density, such as anthracite and activated carbon; the particle size of the middle filter media is moderate, and the density is moderate, generally composed of quartz sand; the lower filter media is composed of heavy filter media with the smallest particle size and the largest density, such as magnetite. Due to the limitation of the density difference, the selection of filter media for the three-layer media filter is basically fixed. The upper filter media plays a role in rough filtration, and the lower filter media plays a role in fine filtration, which gives full play to the role of the multi-media filter bed, and the effluent water quality is significantly better than that of the filter bed with a single layer of filter media. For drinking water, the use of filter media such as anthracite and resin is generally prohibited. V. Quartz Sand Filters The quartz sand filter is a filter that uses quartz sand as the filter media. It can effectively remove suspended solids in water, and has an obvious removal effect on pollutants in water such as colloids, iron, organic matter, pesticides, manganese, bacteria, and viruses. It has the advantages of small filtration resistance, large specific surface area, strong acid and alkali resistance, oxidation resistance, a wide PH application range of 2-13, and good pollution resistance. The unique advantages of the quartz sand filter also lie in that through the optimization of the design of the filter media and the filter, the self-adaptive operation of the filter is realized. The filter media has a strong adaptability to the raw water concentration, operating conditions, pretreatment process, etc., that is, during the filtration process, the filter bed automatically forms a state of being loose at the top and dense at the bottom, which is conducive to ensuring the effluent water quality under various operating conditions. During the backwashing process, the filter media are fully dispersed, and the cleaning effect is good. The sand filter has the advantages of fast filtration speed, high filtration accuracy, and large dirt interception capacity. It is widely used in the pretreatment fields of various process water, domestic water, circulating water and wastewater in industries such as power, electronics, beverages, tap water, petroleum, chemical industry, metallurgy, textile, papermaking, food, swimming pools, and municipal engineering. The quartz sand filter equipment has the characteristics of simple structure, automatic operation control, large processing flow, few backwashing times, high filtration efficiency, small resistance, convenient operation and maintenance, etc. VI. Activated Carbon Filters The filter media is activated carbon, which is used to remove color, taste, residual chlorine and organic matter. Its main action mode is adsorption, and activated carbon is an artificially made adsorbent. Activated carbon filters are widely used in the pretreatment of water for domestic use, food industry, chemical industry, power industry and other industries. Due to the well-developed pore structure and huge specific surface area of activated carbon, it has a strong adsorption capacity for dissolved organic matter in water, such as benzene compounds, phenolic compounds, etc. Moreover, it has a good removal effect on organic pollutants that are difficult to remove by biological and chemical methods, such as color, peculiar smell, surfactants, synthetic detergents and dyes. The removal rate of ions such as Ag⁺, Cd²⁺, CrO₄²⁻ in water by granular activated carbon can reach more than 85%. After passing through the activated carbon filter bed, the suspended solids in water are less than 0.1mg/L, the COD removal rate is generally 40% to 50%, and the free chlorine is less than 0.1mg/L. VII. Backwashing Process The backwashing of the filter mainly refers to that after the filter has been used for a certain period, the filter media layer intercepts and adsorbs a certain amount of sundries and stains, which makes the effluent water quality of the filter decline. The main manifestations are: the quality of the normal filtered water of the filter deteriorates, the pressure difference between the inlet and outlet pipes increases, and at the same time, the flow rate of a single filter decreases. The principle of backwashing: The water flows in the reverse direction through the filter media layer, making the filter layer expand and suspend. With the help of the shearing force of the water flow and the collision friction force of the particles, the filter media layer is cleaned, so that the dirt in the filter layer is separated and discharged with the backwashing water. Find competitive multi-media filter housings here! Contact us at hz_amanda@126.com