Double-layer filter material biological aerated filter

Abstract

The invention provides a double-layer filter material biological aerated filter, which is mainly composed of a water inflow distribution device, a support layer, a double filter material layer, a process aerating device, a backwash aerating device, a central drainage device, and a water outlet; and is characterized in that: a piece of equipment is filled with filter materials of coarse and fine different diameters to form a double filter material layer, which is used for realizing simultaneous decarburization and nitrification functions, the central drainage device is arranged at a place of junction of the upper and lower filter material layer, the branch pipe of a central drainage pipe is opened with small holes for discharging backwash sludge, and two lower layers can make use of different backwash modes. The double-layer filter material biological aerated filter has the advantages that: (1) decarburization and nitrification functions can be simultaneously achieved in a BAF, the filter has a high removal rate for organic matters and ammonia nitrogen, the backwash water consumption is low; and (2) the gas-water ratio is low and only of 2:1-6:1, the operating cost is low, the floor space is small, the system is simple, and the investment is small.

Description

technical field [0001] The invention belongs to a sewage treatment device, in particular to a double-layer filter material aerated biological filter for treating low-concentration domestic sewage. Background technique [0002] Biological aerated filter (BAF) is a sewage treatment process that emerged in the late 1980s and early 1990s. It was initially used as a tertiary treatment, and later developed into a direct secondary treatment. It uses rough and porous granular filter material. Biofilm grows on the surface of the filter material, and aeration is provided at the bottom of the pool. When the sewage flows through the filter bed, the pollutants are first filtered and adsorbed, and then oxidized and decomposed by the microorganisms on the surface of the filter material. Its biggest feature is that it integrates biological oxidation and interception of suspended solids, saves subsequent sedimentation tanks, has the advantages of large volume load, short hydraulic retention ...

AI Technical Summary

Problems solved by technology

Due to the short age and rapid growth of heterotrophic bacteria sludge, the water head loss in the filter layer near the water inlet increases rapidly, requiring frequent backwashing. If the backwashing water distribution is uneven, the phenomenon of filter material sticking is easy to occur, and finally It will cause the quality of the effluent from the filter to deteriorate, the resistance will increase, and it will have to be shut down for maintenance

(3) BloFOR is not easy to backwash

Strong backwashing intensity, large backwashing water consumption (up to 40%), long backwashing time, and long recovery time after backwashing (>Zh)

(4) It is not conducive to complete the decarburization and nitrification functions at the same time

If the removal of organic matter and ammonia nitrogen is completed in one equipment, it will affect the growth of nitrifying bacteria due to the rapid growth of heterotrophic bacteria and the need for frequent backwashing

If the decarburization and nitrification functions are completed in two series-connected BAFs, since the removal of organic matter is completed in a very short area, the height of the decarburization section is very low at a normal flow rate of 4-6m / h, causing equipment If the load is increased by increasing the filtration rate, the power loss will be increased and the backwash cycle will be shortened, which is also uneconomical

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