Biological aerated filter with large particle-size and light-weight filler at surface layer

Abstract

The invention discloses a biological aerated filter with large particle-size and light-weight filter at the surface layer, wherein a filter unit of the biological aerated filter is provided with a support layer (1) and a filtering material layer (2) from bottom to top. The biological aerated filter is characterized in that a large particle-size and light-weight filter layer (3) is arranged at the upper part of the filtering material layer (2). In the biological aerated filter, filtering materials with different particle sizes are adopted, wherein the filtering material with larger particle size is adopted in the support layer, the material with smaller particle size is adopted in a middle layer, and the light-weight filtering material with larger particle size is added in the surface layer. The light-weight filtering material with larger particle size in the surface layer plays a pretreatment role and ensures that not only the biological treatment can be carried out in the surface layer, but also a great deal of SS can be accommodated, thereby reducing the accumulation speed of the SS amount of the filtering material in the middle layer, prolonging the time that the flow volume reaches a critical value and also the backwashing period of the biological filter, improving the efficiency, saving the backwashing water consumption and reducing the operation cost; and the filter has relatively unchanged structure layer position after backwashing, stable water outlet and higher quality.

Description

Technical field: [0001] The invention relates to a sewage downward flow aerated biological filter, in particular to an aerated biological filter with three layers of filters. Background technique: [0002] Microbial cells can firmly attach to almost any suitable carrier surface in the water environment, and grow and multiply on it. The extracellular polymers extending from the inside of the cell to the outside of the cell make the microbial cells form a fibrous tangle structure, which is convenient called a biofilm. The particulate matter in the feed water of the biological aerated filter is trapped on the surface of the filter and in the voids of the packing, and the excessively grown microorganisms also gather on the surface of the filter and in the voids of the packing. With the continuous operation of the treatment process, the SS in the packing increases, Porosity is reduced. At or near the design flow rate, the total head loss approaches the head necessary to pass th...

AI Technical Summary

Problems solved by technology

However, frequent flushing will cause the biofilm to fall off seriously, resulting in the reduction of biomass in the packing layer, which will aff

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