AAO continuous flow aerobic granular sludge nitrogen and phosphorus removal process and system
Technical Field
The invention relates to an AAO continuous flow aerobic granular sludge nitrogen and phosphorus removal process and system.
Technical Field
Compared with common activated sludge, the aerobic granular sludge technology has the characteristics of good sedimentation performance, high sludge concentration, capability of bearing high organic load, load impact, toxic substances and the like, and is a hotspot for research and report in various circles. Generally, the formation of aerobic granular sludge is a complex process comprising physical, chemical and biological actions, and the mainstream thinking describes the process as the phenomenon of organism agglomeration formed by the self-immobilization of microorganisms under certain hydrodynamic conditions. At present, the main flow mechanisms of aerobic granular sludge formation mainly include an extracellular polymer hypothesis, a self-aggregation principle, a filamentous bacteria hypothesis and a condensation nucleus mechanism. The coagulation nucleus mechanism is that aerobic granular sludge is formed, firstly, a coagulation nucleus is needed to provide a place for the aggregation and growth of microorganisms, organic small particles in water can secrete extracellular polymers under the action of hydraulic shearing force, the hydrophobicity of the cell surface is improved, the Gibbs free energy of the cell surface is reduced, and favorable conditions are provided for intercellular interaction and adhesion. Researches show that mineralized substances mainly containing metal elements such as phosphorus, calcium, magnesium and the like exist in the aerobic granular sludge, so that the mineralized substances have an important effect on the formation and the stability of the aerobic granular sludge, and meanwhile, the biological phosphorus removal function is enhanced. Most of the research is focused on sequencing batch reactors at present, and few reports are reported on the process for treating sewage by aerobic granular sludge in continuous flow.
The AAO process is a short name of an anaerobic-anoxic-aerobic method, is a common sewage treatment process and has the functions of nitrogen and phosphorus removal. In the anaerobic reactor, raw sewage and phosphorus-containing return sludge discharged from a sedimentation tank synchronously enter, the main function is to release phosphorus, and meanwhile, part of organic matters are aminated; in the anoxic reactor, the primary function is denitrification, nitrate nitrogen is sent from the aerobic reactor through internal circulation, and the amount of circulating mixed liquid is large, generally 2Q (Q is the flow of raw sewage); removing BOD in an aerobic reactor, namely an aeration tank, and carrying out nitrification and phosphorus absorption; the main function of the sedimentation tank is mud-water separation, one part of sludge flows back to the anaerobic reactor, and supernatant is discharged as treated water. The AAO process is widely applied as a traditional process, but has the defects of anaerobic environment damage caused by a large amount of nitrate ions carried by return sludge, insufficient supply of denitrification carbon source, low biological phosphorus removal efficiency and the like.
Disclosure of Invention
Aiming at overcoming the problems of culture, application and the like of the aerobic granular sludge in continuous flow and aiming at the characteristics and the defects of the AAO process, the invention provides an AAO continuous flow aerobic granular sludge nitrogen and phosphorus removal process.
In order to solve the problems, the following technical scheme is provided:
the utility model provides an AAO continuous flow good oxygen granule sludge nitrogen and phosphorus removal technology, the biochemical pond of getting into behind thick and thin grid, the primary sedimentation pond of intaking in proper order, biochemical pond constitute by anaerobic tank, oxygen deficiency pond and the aerobic tank that sets gradually, biochemical pond goes out partly backward flow of water to oxygen deficiency pond front end, another part gets into two heavy ponds and carries out mud-water separation, two heavy ponds be two district sedimentation tanks, light in weight's mud is collected the back and directly gets into concentrated mummification outward transport and handle, and the mud that the weight is heavy is collected the back partly and flows back to the anaerobic tank front end as surplus sludge, and another part is gone on the mummification and is smashed and put in to biochemical pond front end, and two heavy ponds go out water and discharge up to standard behind the disinfection facility.
A system of an AAO continuous flow aerobic granular sludge nitrogen and phosphorus removal process comprises a coarse and fine grid, a primary sedimentation tank, a biochemical tank and a secondary sedimentation tank, the inlet of the coarse and fine grid is a total water inlet, the outlet of the coarse and fine grid is communicated with the inlet of the primary sedimentation tank, the outlet of the primary sedimentation tank is communicated with the inlet of a biochemical tank, the biochemical tank consists of an anaerobic tank, an anoxic tank and an aerobic tank which are arranged in sequence, one part of the outlet of the aerobic tank is communicated with the front end of the anoxic tank through an internal return pipe, the other part of the outlet of the aerobic tank is communicated with the inlet of the secondary sedimentation tank, the secondary sedimentation tank is a double-zone sedimentation tank, a light sludge outlet of the double-zone sedimentation tank is provided with a concentration drying outward conveying device, one part of the heavy sludge outlet of the double-zone sedimentation tank is communicated with the front end of the anaerobic tank through a return pipe, and the other part of the heavy sludge outlet of the double-zone sedimentation tank is communicated with the inlet of the biochemical tank through drying and crushing equipment; the water outlet of the double-area sedimentation tank is communicated with the main water outlet after passing through a disinfection facility.
The technical conception of the invention is as follows: the invention adopts the double-zone sedimentation tank to separate and collect the sludge according to the weight, the sludge with the light weight is composed of the microorganisms with shorter generations and is directly discharged out of the sewage treatment system, the sludge with the heavy weight is composed of the microorganisms with longer generations, and one part of the sludge flows back, thereby being beneficial to the denitrification and dephosphorization of the microorganisms, promoting the improvement of the sludge quality in the biochemical tank and being beneficial to the granulation of the aerobic sludge; the sludge with heavy weight is dried and crushed and then used as second sludge to flow back to a sewage treatment system, the formation and the stability of aerobic granular sludge are promoted by utilizing a condensation nucleus mechanism, and a carbon source is provided for denitrification; after the aerobic granular sludge is formed, the sludge-water separation effect is improved, and the biological nitrogen and phosphorus removal is enhanced by utilizing mechanisms such as synchronous nitrification and denitrification, biological mineralization and the like; the sludge is recycled, the addition of external carbon sources and the disposal of the sludge are reduced, and certain economic benefit is obtained.
The beneficial effects of the invention are mainly embodied as follows:
(1) and (3) selectively collecting sludge by using a double-zone sedimentation tank, and manually separating the sludge according to the weight.
(2) The sludge is utilized in a targeted manner according to characteristics, the sludge with light weight is directly discharged from a sewage treatment system to directly remove biological organic matters and phosphorus, one part of the sludge with heavy weight flows back to a biochemical tank to promote the high force and granulation of the sludge quality, so that biological nitrogen and phosphorus removal is facilitated, the other part of the sludge with heavy weight is dried and crushed to be used as second sludge to flow back, and the formation of aerobic granular sludge is promoted to improve the sludge-water separation efficiency and strengthen the biological nitrogen and phosphorus removal.
(3) The method has the advantages of recycling waste, utilizing excess sludge for recycling, providing crystal nuclei for granulation of aerobic sludge, providing a carbon source for denitrification, and reducing the additional carbon source and sludge treatment cost.
(4) The improvement is simple, and to current a large amount of sewage treatment facilities that adopt the AAO technology, only need carry out simple transformation with sedimentation tank and pipe network, utilize its original sludge drying facility, only need add crushing apparatus, and it is simple and convenient to implement, with low costs.
Drawings
FIG. 1 is a schematic flow diagram of an AAO continuous flow aerobic granular sludge nitrogen and phosphorus removal process.
Detailed Description
The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto.
Referring to fig. 1, an AAO continuous flow aerobic granule sludge nitrogen and phosphorus removal technology, the influent water gets into biochemical pond after thick and thin grid, the primary sedimentation pond in proper order, biochemical pond constitute by anaerobic tank, oxygen deficiency pond and the aerobic tank that sets gradually, biochemical pond effluent is partly to flow back to oxygen deficiency pond front end, another part gets into two sedimentation tanks and carries out mud-water separation, two sedimentation tanks be two district sedimentation tanks, light in weight's mud is collected the back and directly gets into concentrated mummification outward transport and deals with, heavy in weight's mud is collected the back partly and flows back to the anaerobic tank front end as surplus mud, another part mummification is smashed and is put in to biochemical pond front end, two sedimentation tanks effluent discharge up to standard behind the disinfection facility.
A system of an AAO continuous flow aerobic granular sludge nitrogen and phosphorus removal process comprises a coarse and fine grid, a primary sedimentation tank, a biochemical tank and a secondary sedimentation tank, the inlet of the coarse and fine grid is a total water inlet, the outlet of the coarse and fine grid is communicated with the inlet of the primary sedimentation tank, the outlet of the primary sedimentation tank is communicated with the inlet of a biochemical tank, the biochemical tank consists of an anaerobic tank, an anoxic tank and an aerobic tank which are arranged in sequence, one part of the outlet of the aerobic tank is communicated with the front end of the anoxic tank through an internal return pipe, the other part of the outlet of the aerobic tank is communicated with the inlet of the secondary sedimentation tank, the secondary sedimentation tank is a double-zone sedimentation tank, a light sludge outlet of the double-zone sedimentation tank is provided with a concentration drying outward conveying device, one part of the heavy sludge outlet of the double-zone sedimentation tank is communicated with the front end of the anaerobic tank through a return pipe, and the other part of the heavy sludge outlet of the double-zone sedimentation tank is communicated with the inlet of the biochemical tank through drying and crushing equipment; the water outlet of the double-area sedimentation tank is communicated with the main water outlet after passing through a disinfection facility.
Example 1: an AAO continuous flow aerobic granular sludge nitrogen and phosphorus removal process, wherein sludge from an aeration tank of a sewage treatment plant is inoculated into a reactor at 1000mg/L, the inoculated sludge is in a floc form, SVI is 80ml/g, and sodium acetate, ammonia oxide and potassium dihydrogen phosphate are prepared into a sludge with COD of 1000mg/L, NH4 +The sewage with the N concentration of 60mg/L, TP and the concentration of 10mg/L is continuously fed with water for operation, the internal reflux ratio of the sludge is set as 2Q (Q is the water inlet flow rate), the light sludge of the double-zone secondary sedimentation tank is directly discharged, one part of the heavy sludge is refluxed, the other part of the heavy sludge is dried and then crushed into 800 meshes and is put into the front end of the biochemical tank, the aerobic sludge is granulated after the reactor is continuously operated for 25 days, the sedimentation degree is 20-30m/h, the SVI is<50ml/g, COD removal rate of about 95%, TN removal rate of about 87% and TP removal rate of about 92%.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.