Vivianite crystal front dephosphorization method based on AAO/AO process

Abstract

The invention discloses a vivianite crystal front dephosphorization method based on the AAO / AO process, and belongs to the technical field of sewage processing. The method includes the steps of makingcrude sewage and sludge flowing back from a secondary depositing pool synchronously enter an anaerobic pool of the AAO / AO process for phosphorus release, putting Fe3+ / Fe2+ salt in the anaerobic pool,reducing Fe3+ into Fe2+ under the effect of dissimilar metal reducing bacteria, making Fe2+ react with phosphorus in the anaerobic pool to generate vivianite crystals, arranging an anaerobic standingarea communicated with the anaerobic pool at the rear end of the anaerobic pool, making sludge-water mixed liquid containing a large amount of vivianite enter the anaerobic standing area for depositing and separating, making the sludge containing a large amount of vivianite at the bottom of the anaerobic standing area discharged out of a system through a sludge discharge pipe, separating out supernate of the vivianite sludge, and making the supernate enter the subsequent stage of the AAO / AO process for processing. The method is simple and easy to implement, basically no additional processingunits need to be added, cost is low, and the dephosphorization effect is good.

Description

technical field [0001] The invention relates to a method for removing phosphorus, in particular to a method for removing phosphorus before crystallization of blue iron ore based on the AAO / AO process, and belongs to the technical field of sewage treatment. Background technique [0002] Phosphorus is an important element that causes water eutrophication. Therefore, with the increasing emphasis on water environmental protection, the state has higher and higher requirements for phosphorus treatment in sewage treatment plants. From the 3.0mg / L required by the secondary discharge standard, the transition 1.0mg / L required by level B, and 0.5mg / L required by most level A currently implemented. Under this requirement, various phosphorus removal processes have also been developed and applied, such as biological methods and chemical precipitation methods. The biological phosphorus removal process is usually AO or AAO process, and the existing AO phosphorus removal process (such as i...

AI Technical Summary

Problems solved by technology

The AO or AAO process is adopted by most sewage treatment plants due to its low operating costs, but a single biological method is difficult to meet the increasingly stringent phosphorus removal requirements, so chemical methods have become the gatekeeper for phosphorus removal in sewage treatment plants

[0003] At present, there have been many reports on chemical phosphorus removal. For example, the Chinese invention patent with the publication number of CN101381184A discloses a sewage treatment system and a treatment method combining biological phosphorus removal and side-channel chemical phosphorus removal. The phosphorus removal method requires additional side-stream phosphorus removal The processing unit is complex in operation and high in cost; the Chinese invention patent with the publication number of CN1654352A discloses a system and method for chemical and biological combined deep phosphorus removal of urban sewage, which directly synchronizes chemical flocculation and biological phosphorus removal in the aeration tank, Phosphorus removal directly in the aeration tank will change the characteristics of biological sludge and affect the effect of phosphorus removal; the invention patent with the publication number of CN105923761A discloses a method for enhanced phosphorus removal of ferrous salt in denitrification phosphorus removal sludge. Dosing Fe directly in the denitrification section 2+ Although the phosphorus removal effect can be enhanced to a certain extent, when using this method to run the existing AAO process, because the sludge age has a great influence on the nitrogen and phosphorus removal effect, denitrification requires activated sludge with a long sludge age, and phosphorus removal requires sludge. Activated sludge with a short age, the contradiction between the two makes the phosphorus removal effect of this method not ideal, and it is difficult to improve

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