Biological aerated filter with three filter layers

Abstract

The invention discloses a biological aerated filter with three filter layers. The biological aerated filter is characterized in that a filter device is provided with a supporting layer (1) with large particle size, a quartz sand filter media layer (2) with the particle size of 4 to 5mm and a light-weight filling layer (3) with the large surface particle size of 6 to 8mm from bottom to top; and the thicknesses of the three layers are respectively 800mm, 2000mm and 1000mm. A layer of light-weight filling media with larger particle size, which have the function of pretreatment, is added to the surface layer so that the surface layer can be used for carrying out biological treatment, can contain a large number of SS (suspended solids), greatly slows down the accumulation speed of the SS quantity of intermediate filter media, prolongs the time for reaching a critical value of flow and the backwashing cycle of the biological aerated filter, improves efficiency, saves water for backwashing and reduces operation costs. In addition, the relative position of the structure layers of the biological aerated filter after backwashing is not changed, and water can be supplied stably with 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 affect the treatment effect, and easily cause damage and loss of packing, and increase unnecessary backwashing water consumption and power consumption.

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