Hydrolytic acidification-catalyzed iron/anaerobic-aerobic biological dephosphorization coupling process

Abstract

The invention relates to a hydrolytic acidification-catalyzed iron / anaerobic-aerobic biological dephosphorization coupling process which is realized by a hydrolytic acidification-catalyzed iron / anaerobic-aerobic biological dephosphorization coupling device. The device is composed of a hydrolytic acidification tank, an anaerobic tank and a catalyzed iron filler therein, an aerobic tank and a precipitation tank which are sequentially connected. The process specifically comprises the following steps: sewage is fed into the hydrolytic acidification tank, and the hydraulic retention time is controlled to be 2-6 hours; the effluent water after hydrolytic acidification reaction is fed into the anaerobic tank, sludge in the anaerobic tank is refluxed by the aerobic tank, the reflux liquid brings dissolved oxygen to destroy the anaerobic phosphorus release environment of phosphorus-accumulating bacteria, and the catalyzed iron can effectively remove the dissolved oxygen and simultaneously form ferrous ions; the effluent water of the anaerobic tank passes through the aerobic tank, and the ferrous ions are oxidized to become ferric ions and be combined with phosphate ions to form precipitates, thus achieving dephosphorization effect; and the effluent water of the aerobic tank is precipitated in the precipitation tank, the effluent water is discharged, and part of sludge is refluxed to the anaerobic tank. The process provided by the invention greatly makes up the limitation of the current biological dephosphorization process, and has favorable application prospects.

Description

technical field [0001] The invention relates to the field of water pollution control engineering, in particular to a phosphorus removal process coupled with biological and physical and chemical methods, in particular to a hydrolytic acidification-catalyzed iron / anaerobic-aerobic biological phosphorus removal coupling process. Background technique [0002] With the development of society and the improvement of people's living standards, the eutrophication of water bodies has attracted more and more attention. The total phosphorus index in the discharge standards of sewage treatment plants has become more and more stringent. Phosphorus and nitrogen have become the main tasks and objectives of upgrading urban sewage treatment plants. Technical Difficulties. [0003] Phosphorus removal in urban sewage treatment plants mostly adopts biological phosphorus removal methods. The advantages are: no need to add chemicals and low cost; biological methods can reduce various pollution ind...

AI Technical Summary

Problems solved by technology

Although the biological phosphorus removal process has the above advantages, the limitations of this method are also prominent: (1) The anaerobic section and the aerobic section must be set up in the phosphorus removal process to meet the physiological requirements of phosphorus-accumulating bacteria and maintain the advantages of phosphorus-removing bacteria. Bacteria need to absorb a large amount of low molecular weight organic acids in the anaerobic stage

The sewage treatment plants with the task of phosphorus removal often also have the task of denitrification, and the biological denitrification method is almost the only choice. The denitrification section of the biological denitrification needs to consume a large amount of easily biodegradable organic matter (including low molecular weight organic acids). Therefore, there is a contradiction between biological phosphorus removal and nitrogen removal competing for carbon sources, and this contradiction is particularly prominent in the treatment of southern urban sewage

(2) There is another contradiction between biological phosphorus removal and nitrogen removal: different sludge age requirements

Although this contradiction can be alleviated by adding biological fillers and other methods, it increases investment and operating costs

(3) Poor stability of biological phosphorus removal

The limitations of the method are: (1) It is necessary to increase the chemical agent dosing unit, which increases the investment and treatment costs, and increases the treatment process; It is not conducive to nitrification reaction; (3) Adding chemical agents increases the salinity in water, which is not conducive to biochemical reactions

Although the method of chemical precipitation and phosphorus removal after biochemical reaction does not cause problems (2) and (3), it affects the water quality and natural deep purification of the water body.

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