Downward flow type denitrification and phosphorous removal expanded bed biological filter and method for treating sewage by applying same

Abstract

The invention discloses a downward flow type denitrification and phosphorous removal expanded bed biological filter and a method for treating sewage by applying the same. The downward flow type denitrification and phosphorous removal expanded bed biological filter comprises a water distribution region, a filter screen plate, a floating ceramsite filter bed, a filter bed fluidization and buffering region, a filter-head filter plate, a water outlet region, a bottom water collection and gas distribution device and a water collection and gas distribution channel box, wherein the floating ceramsite filter bed is composed of crushed shale floating ceramsite arranged between the filter screen plate and the filter-head filter plate; the crushed shale floating ceramsite has an irregular shape and the density of water wetted particles is 0.95g / cm<3>+ / -0.5g / cm<3>; shale ceramsite is coarse and hydrophilic so that biofilm colonization is easy to realize; backwashing is adopted so that the activity of a biofilm is easy to maintain, the de-mold is not liable to occur and a denitrification biological nitrogen removal function is prominent; after sewage is subjected to primary micro-flocculation in the water distribution region, phosphorous-containing floc has a deep penetration distance in an expanded filter bed gap and a phosphorous removal effect is facilitated; the crushed ceramsite and the relatively large filter bed depth ensure the phosphorous removal and filtering capability. By adopting the downward flow type denitrification and phosphorous removal expanded bed biological filter, the loss of a filtering water head of an expanded bed is small and a filtering material is easy to fluidize and is not hardened.

Description

Technical field [0001] The invention relates to the field of water treatment, in particular to an expanded bed biological filter for denitrification and phosphorus removal and a method for applying the same to sewage denitrification and phosphorus removal. Background technique [0002] At present, my country's water bodies are polluted by nitrogen and phosphorus, which leads to serious eutrophication problems. Therefore, nitrogen and phosphorus are used as the key emission control indicators for sewage treatment. Sewage treatment usually adopts biological denitrification and phosphorus removal process, which uses denitrifying bacteria to convert nitrate nitrogen in the water into nitrogen and releases it from the water. Through the assimilation and adsorption of microorganisms, the phosphorus in the sewage is separated and removed with the microorganisms and sewage. For biological nitrogen and phosphorus removal. However, when the nitrogen and phosphorus indicators are strictly ...

AI Technical Summary

Problems solved by technology

However, most of the existing micro-flocculation biofilters for denitrification and phosphorus removal are fixed beds, and quartz sand or clay ceramsite is used as the filter material, which is still lacking in the coordination of biochemical and filtration functions. Good, but the surface of quartz sand is hard and smooth, and the performance of biofilm is poor, especially backwashing can easily lead to the complete elution of biofilm, and the denitrification effect is seriously damaged

As for the fixed bed of clay ceramsite filter material, due to its high density, backwashing consumes a lot of energy, and the filter material has an obvious tendency to harden, and the biochemical effect decreases accordingly.

For spherical ceramsite, it will also cause filtration leakage due to the large gap, which will have an adverse effect on the phosphorus removal effect.

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