CN115448449B - Denitrification carrier, and preparation method, device and application thereof - Google Patents
Denitrification carrier, and preparation method, device and application thereof Download PDFInfo
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- CN115448449B CN115448449B CN202110637543.4A CN202110637543A CN115448449B CN 115448449 B CN115448449 B CN 115448449B CN 202110637543 A CN202110637543 A CN 202110637543A CN 115448449 B CN115448449 B CN 115448449B
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- 238000002360 preparation method Methods 0.000 title claims description 14
- 239000003963 antioxidant agent Substances 0.000 claims abstract description 25
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 93
- 239000002245 particle Substances 0.000 claims description 45
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 44
- 238000000034 method Methods 0.000 claims description 38
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 34
- 239000000463 material Substances 0.000 claims description 31
- 238000009826 distribution Methods 0.000 claims description 25
- 230000008569 process Effects 0.000 claims description 25
- 239000012530 fluid Substances 0.000 claims description 24
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- 229910052757 nitrogen Inorganic materials 0.000 claims description 22
- 238000006116 polymerization reaction Methods 0.000 claims description 22
- XYLMUPLGERFSHI-UHFFFAOYSA-N alpha-Methylstyrene Chemical compound CC(=C)C1=CC=CC=C1 XYLMUPLGERFSHI-UHFFFAOYSA-N 0.000 claims description 17
- 238000002156 mixing Methods 0.000 claims description 17
- -1 polypropylene Polymers 0.000 claims description 12
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- 238000005470 impregnation Methods 0.000 claims description 10
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- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical compound O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 9
- 230000000630 rising effect Effects 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 8
- JKIJEFPNVSHHEI-UHFFFAOYSA-N Phenol, 2,4-bis(1,1-dimethylethyl)-, phosphite (3:1) Chemical compound CC(C)(C)C1=CC(C(C)(C)C)=CC=C1OP(OC=1C(=CC(=CC=1)C(C)(C)C)C(C)(C)C)OC1=CC=C(C(C)(C)C)C=C1C(C)(C)C JKIJEFPNVSHHEI-UHFFFAOYSA-N 0.000 claims description 7
- BGYHLZZASRKEJE-UHFFFAOYSA-N [3-[3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoyloxy]-2,2-bis[3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoyloxymethyl]propyl] 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate Chemical compound CC(C)(C)C1=C(O)C(C(C)(C)C)=CC(CCC(=O)OCC(COC(=O)CCC=2C=C(C(O)=C(C=2)C(C)(C)C)C(C)(C)C)(COC(=O)CCC=2C=C(C(O)=C(C=2)C(C)(C)C)C(C)(C)C)COC(=O)CCC=2C=C(C(O)=C(C=2)C(C)(C)C)C(C)(C)C)=C1 BGYHLZZASRKEJE-UHFFFAOYSA-N 0.000 claims description 7
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- 239000004698 Polyethylene Substances 0.000 claims description 4
- 229920000573 polyethylene Polymers 0.000 claims description 4
- 238000002791 soaking Methods 0.000 claims description 4
- QSRJVOOOWGXUDY-UHFFFAOYSA-N 2-[2-[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoyloxy]ethoxy]ethoxy]ethyl 3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoate Chemical compound CC(C)(C)C1=C(O)C(C)=CC(CCC(=O)OCCOCCOCCOC(=O)CCC=2C=C(C(O)=C(C)C=2)C(C)(C)C)=C1 QSRJVOOOWGXUDY-UHFFFAOYSA-N 0.000 claims description 2
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- 238000011068 loading method Methods 0.000 claims description 2
- SSDSCDGVMJFTEQ-UHFFFAOYSA-N octadecyl 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate Chemical compound CCCCCCCCCCCCCCCCCCOC(=O)CCC1=CC(C(C)(C)C)=C(O)C(C(C)(C)C)=C1 SSDSCDGVMJFTEQ-UHFFFAOYSA-N 0.000 claims description 2
- 239000002530 phenolic antioxidant Substances 0.000 claims description 2
- 229920006122 polyamide resin Polymers 0.000 claims description 2
- 229920001748 polybutylene Polymers 0.000 claims description 2
- 229920013716 polyethylene resin Polymers 0.000 claims description 2
- 229920005990 polystyrene resin Polymers 0.000 claims description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 2
- WVLBCYQITXONBZ-UHFFFAOYSA-N trimethyl phosphate Chemical compound COP(=O)(OC)OC WVLBCYQITXONBZ-UHFFFAOYSA-N 0.000 claims description 2
- XZZNDPSIHUTMOC-UHFFFAOYSA-N triphenyl phosphate Chemical compound C=1C=CC=CC=1OP(OC=1C=CC=CC=1)(=O)OC1=CC=CC=C1 XZZNDPSIHUTMOC-UHFFFAOYSA-N 0.000 claims description 2
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- 239000007790 solid phase Substances 0.000 abstract description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 10
- 239000010842 industrial wastewater Substances 0.000 description 10
- 239000010802 sludge Substances 0.000 description 10
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- 229910002092 carbon dioxide Inorganic materials 0.000 description 5
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- MMDJDBSEMBIJBB-UHFFFAOYSA-N [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] Chemical compound [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] MMDJDBSEMBIJBB-UHFFFAOYSA-N 0.000 description 2
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
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- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- XOZUGNYVDXMRKW-AATRIKPKSA-N azodicarbonamide Chemical compound NC(=O)\N=N\C(N)=O XOZUGNYVDXMRKW-AATRIKPKSA-N 0.000 description 1
- 235000019399 azodicarbonamide Nutrition 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000000071 blow moulding Methods 0.000 description 1
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- FPAFDBFIGPHWGO-UHFFFAOYSA-N dioxosilane;oxomagnesium;hydrate Chemical compound O.[Mg]=O.[Mg]=O.[Mg]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O FPAFDBFIGPHWGO-UHFFFAOYSA-N 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
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- 239000000178 monomer Substances 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 150000001451 organic peroxides Chemical group 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/28—Anaerobic digestion processes
- C02F3/2806—Anaerobic processes using solid supports for microorganisms
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/28—Anaerobic digestion processes
- C02F3/2846—Anaerobic digestion processes using upflow anaerobic sludge blanket [UASB] reactors
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/28—Anaerobic digestion processes
- C02F3/2866—Particular arrangements for anaerobic reactors
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/38—Organic compounds containing nitrogen
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Abstract
The invention relates to a denitrification carrier composition, which comprises the following raw materials in parts by weight: 100 parts of a thermoplastic resin, based on 100 parts of the thermoplastic resin, further comprising: 0.05 to 1 part of antioxidant, preferably 0.1 to 0.5 part; and 0.5 to 30 parts, preferably 5 to 15 parts of filler. The denitrification carrier composition adopts thermoplastic resin, is compounded with antioxidant and filler, and the carrier prepared from the denitrification carrier composition has controllable density range and large specific surface area, controllable pore channel structure, high mechanical strength and long service life; the pore wall is rough, denitrifying bacteria are easy to attach, the reactor is started quickly, and the biological membrane in the carrier area is high; the fluidization of the solid phase and the liquid phase is easy to fluidize, is beneficial to the contact and mass transfer of microorganisms and sewage, and has high denitrification efficiency; the denitrification carrier biomembrane volume can realize self-balancing in operation, avoids the need of staged backwashing of a conventional fixed bed, and has high denitrification load.
Description
Technical Field
The invention belongs to the technical field of chemical industry and environmental protection, in particular relates to a wastewater technology, and further relates to a denitrification carrier, and a preparation method, a device and application thereof.
Background
In recent years, nitrogen pollution in the field of water treatment has become one of the social hot spots. Removal of nitrogen from water is one of the key problems of concern in the water treatment field. How to economically, efficiently and safely remove total nitrogen from water, develop a high-efficiency and stable bio-enhanced denitrification technology, and become a problem to be solved in the field of sewage treatment.
Biological denitrification is widely focused on the lower treatment cost, and the denitrification process commonly used in the sewage treatment field at present is a traditional activated sludge process. However, the activated sludge process has disadvantages in that the concentration of sludge is low, high-load sewage cannot be treated, and the sludge is easily expanded, occupies a large area, requires large-scale precipitation equipment, and has a large amount of surplus sludge. The biomembrane method is developed rapidly by virtue of the characteristics of high treatment efficiency, small sludge yield of residual sludge, convenient operation management and the like, and has wide application prospect in sewage treatment.
Patent CN211497306U discloses a deep-bed denitrification filter, which adopts sea sand and fine sand as filter material layers, has smaller specific surface area, fewer denitrification biological membranes, lower denitrification capacity load and lower total nitrogen concentration of water inlet which needs to be ensured to be lower.
Patent CN212246397U discloses a novel denitrification filter device based on organic polymer carrier can effectively evenly distribute water, avoids water fall and mixed dissolved oxygen in the conventional denitrification filter water distribution process, reduces the addition of extra carbon sources, but needs frequent backwashing, and influences the normal operation stability.
The carrier in the biomembrane process is used as the important component of the reactor, and is the carrier of the microbial film, and the surface property and the hydraulic fluidization property of the carrier influence the mass transfer efficiency of the substrate. The quality of the carrier performance directly influences the difficulty of film formation, the adhesion quantity of the biological film and the denitrification treatment load, and is important to improving the treatment efficiency of the biological film reactor and reducing the operation cost. Aiming at the current technological conditions of the operation of the biomembrane reactor in water treatment, the development of a novel denitrification functional carrier is needed to improve biomembrane activity and treatment load, realize high-efficiency denitrification, avoid periodic backwashing and reduce the operation and maintenance cost of the reactor.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a novel high-efficiency denitrification biological carrier for effectively removing total nitrogen in nitrogen-containing wastewater through biological denitrification.
For this purpose, the invention provides a denitrification carrier composition, which comprises the following raw materials in parts by weight: 100 parts of a thermoplastic resin, based on 100 parts of the thermoplastic resin, further comprising:
0.05-1 part of antioxidant, preferably 0.1-0.5 part of antioxidant;
and 0.5 to 30 parts, preferably 5 to 15 parts of filler.
The following raw materials used in the present invention are all commercially available or may be prepared by laboratory, and the present invention is not particularly limited thereto.
As a specific embodiment of the present invention, the thermoplastic resin is at least one selected from the group consisting of polyethylene resin, polypropylene resin, polyethylene compound resin, polystyrene resin, styrene-butadiene rubber resin, ABS resin and polyamide resin.
Preferably, the thermoplastic resin is at least selected from one polyolefin resin.
More preferably, the thermoplastic resin is at least one selected from the group consisting of polypropylene, polyethylene, polybutylene, and polypentene;
the antioxidant of the present invention may be any antioxidant conventionally used in the art, and the present invention is not particularly limited thereto.
The antioxidant is at least selected from hindered phenol antioxidants and/or phosphite antioxidants.
Preferably, the antioxidant is a hindered phenol antioxidant and a phosphite antioxidant in a mass ratio of 1 (0.8-1.2), for example, in a range of 1:0.8,1:1,1:1.2, and any combination thereof.
More preferably, the hindered phenolic antioxidant is selected from at least antioxidant 1010, antioxidant 1076, antioxidant 245 and antioxidant 246.
And/or the phosphite antioxidant is at least selected from triphenyl phosphate, trimethyl phosphate, and antioxidant 168.
In a specific embodiment of the present invention, the filler is a terpolymer microsphere. In the invention, the terpolymer is a copolymer formed by copolymerization of 3 monomers (such as maleic anhydride, styrene and alpha-methyl styrene), and the terpolymer microsphere is a sphere.
Preferably, the filler is a maleic anhydride-styrene-alpha-methylstyrene terpolymer microsphere.
More preferably, the molar ratio of styrene to alpha-methylstyrene is in the range of 9:1 to 1:9, such as 9:1,6:1,3:1,1:1,1:3,1:6,1:9, and any combination thereof.
Further preferably, the molar content of the structural units provided by maleic anhydride is 48% -51%, the molar content of the structural units provided by styrene is 10% -45%, and the molar content of the structural units provided by alpha-methyl styrene is 10% -45% based on the molar amount of the copolymer structural units in the filler.
In a specific embodiment of the present invention, the average particle diameter of the terpolymer microsphere is 500nm to 1600nm, preferably 800nm to 1500nm, for example 800nm,1000nm, 1200nm, 1500nm and any combination thereof.
In a second aspect, the present invention provides a denitrification carrier prepared from the composition.
As a specific embodiment of the present invention, the average particle diameter of the denitrification carrier is in the range of 1mm to 6mm, preferably 2mm to 2.5mm, for example, 2mm, 2.2mm, 2.5mm and any combination thereof.
As a specific embodiment of the present invention, the specific surface area of the denitrification carrier is 1m 2 /g~100 m 2 /g, preferably 10m 2 /g~60 m 2 /g, e.g. 10m 2 /g， 30 m 2 /g， 60 m 2 Ranges of/g and any combination thereof.
As a specific embodiment of the present invention, the apparent density of the denitrification carrier is 0.20. 0.20 g/cm 3 ~0.80 g/cm 3 Preferably 0.45. 0.45 g/cm 3 ~0.75 g/cm 3 For example 0.45 g/cm 3 ， 0.55 g/cm 3 ， 0.65 g/cm 3 ， 0.75 g/cm 3 And any combination thereof.
As a specific embodiment of the present invention, the open-close ratio of the carrier may be adjusted according to the need and specific process, and the closed-close ratio of the denitrification carrier is in the range of 1% -99%, preferably 25% -60%, for example 25%,35%,45%,60% and any combination thereof.
The denitrification carrier has controllable density range, large specific surface area, high mechanical strength and long service life; the pore wall is rough, the pore structure is controllable, the denitrification functional bacteria can be effectively attached, and the reactor is started quickly; easy expansion fluidization, no need of periodic backwashing, realization of self-balancing of the biological film and stable operation.
In a third aspect, the present invention provides a method for preparing the denitrification carrier, comprising the steps of:
s101: mixing the raw materials, extruding, molding and granulating. The particle diameter and the surface roughness of the particles can be controlled by adjusting the feeding speed and the granulating speed.
S102: and (3) drying the particles obtained in the step (S101), and then introducing supercritical fluid to impregnate the particles to prepare the carrier. In the present invention, the supercritical fluid may be supercritical nitrogen, supercritical carbon dioxide, or the like, and the present invention is not particularly limited thereto.
S103: and (3) cooling the carrier prepared in the step (S102) and then carrying out pore canal regulation. And S102, cooling to obtain a denitrification carrier, regulating and controlling the pore channels, filling the carrier with high surface roughness into the communicated pore channels, regulating and controlling the parameters of the treatment process such as pressure, time, temperature and the like by supercritical gas treatment, separating out the filler from the surface of the pore walls, forming a large number of round holes on the pore walls, increasing the roughness of the pore walls, and greatly improving the specific surface area of the carrier.
The preparation method of the denitrification carrier of the invention comprises the steps of taking one or more thermoplastic resins as base resin, mixing with an antioxidant and a filler according to a certain proportion, extruding and granulating, and then carrying out supercritical gas treatment to prepare the thermoplastic resin porous foam with rough outer surface and inner hole wall. The porous ceramic material has the characteristics of easiness in adhesion of microorganisms, adjustable density, excellent mechanical properties, adjustable pore structure, high roughness of the outer surface of particles and the inside of pores and large specific surface area.
The apparent density, pore structure and specific surface area of the carrier are regulated and controlled by controlling the conditions of process temperature, pressure, impregnation time, pressure relief rate and the like.
In step S101, the granulation may be performed by a twin-screw extruder, or may be performed by injection molding, compression molding, blow molding, die casting, hollow molding, vacuum molding, or other processing methods to obtain molded articles such as sheets, blocks, rods, and hollow tubes.
As a specific embodiment of the present invention, in the step S101, the extrusion temperature is in a range of 170 ℃ to 230 ℃, preferably 180 ℃ to 200 ℃, for example 180 ℃, 190 ℃, 200 ℃, and any combination thereof.
As a specific embodiment of the present invention, the dicing speed is in the range of 100 rpm to 500 rpm, preferably 200 rpm to 300rpm, for example 200 rpm, 250rpm, 300rpm, and any combination thereof.
In the step S102, the treatment temperature of the supercritical fluid treatment apparatus is 130 to 180 ℃, preferably 140 to 165 ℃, such as 140, 145, 150, 155, 160, 165, and any combination thereof.
As a specific embodiment of the present invention, the working pressure of the supercritical fluid processing apparatus is in the range of 1.0MPa to 25.0MPa, preferably 7.3MPa to 15.0MPa, for example, 7.3MPa, 8.5MPa, 10.0MPa, 12.0MPa, 15.0MPa, and any combination thereof.
As a specific embodiment of the present invention, the soaking time is in the range of 1 min to 1h, preferably 10min to 30min, for example, 10min, 20min, 30min, and any combination thereof.
As a specific implementation mode of the invention, after the supercritical processing device is adopted for soaking, one-time pressure relief is adopted during pressure relief, and the pressure relief speed is 0.1 MPa/min-30 MPa/min, preferably 1 MPa/min-10 MPa/min; and/or after the impregnation is finished by adopting the supercritical processing device, adopting multiple segmented pressure relief when the pressure is relieved, wherein the pressure relief speed of each segment is 1 MPa/min-30 MPa/min, and preferably 3 MPa/min-15 MPa/min.
In a fourth aspect, the present invention provides an apparatus filled with the denitrification carrier.
The device adopts the anoxic expansion bed, adopts the anti-blocking filter head for water distribution, improves the uniformity of water distribution and increases the effective utilization rate of the carrier layer; the device occupies small area, runs stably and has high denitrification load.
As a specific embodiment of the invention, the device comprises an upflow expansion bed reactor, wherein the upflow expansion bed reactor comprises a feeding area, a water distribution area, a carrier area, a three-phase separation area and a water outlet area from bottom to top, and the carrier area is filled with a denitrification carrier.
Preferably, the loading volume of the denitrification carrier accounts for 20% -80% of the volume of the carrier zone.
Preferably, the apparatus may further comprise a wastewater treatment apparatus comprising an auxiliary line.
As shown in fig. 1 and 2, the bio-expansion bed can be vertically arranged in a cylindrical structure, can be made of steel plates, glass or other materials, has a circular cross section, has a large upper section and a small lower section, and is respectively provided with a feeding area, a water distribution area, a carrier area, a three-phase separation area and a water outlet area from bottom to top, wherein a certain number of filter heads are assembled on a distribution plate in the water distribution area to realize uniform water distribution; the carrier area is filled with denitrification carriers; the three-phase separation area consists of a central tube and a bell mouth-shaped cover body, the flaring end of the cover body is downward, carrier separation is realized, and carrier loss is prevented; a water collecting tank and a water outlet weir are arranged at the periphery of the top of the water outlet area; the outer side of the water outlet weir is provided with a water outlet filter screen and a filter screen cleaning system.
The bottom of the upflow expanded bed reactor is uniformly distributed by the filter head, a carrier region is realized by the circulating system, which is favorable for substrate transmission and blockage prevention, biomembrane self-balancing is realized by friction among carriers, the water flux of the filter screen is kept by the filter screen cleaning system, the continuous mud discharge of the device water outlet is realized, and carrier loss is prevented.
Preferably, the height-to-diameter ratio of the upflow expanded bed reactor is (1-8): 1, more preferably (2 to 4): 1.
the three-phase separator consists of a central tube, a horn-shaped upper cover body, a lower cover body and a connecting piece, wherein the flaring ends of the upper cover body and the lower cover body are downward, the shrinking end of the upper cover body is connected with the lower port of the central tube, and the upper cover body is connected with the lower cover body by the connecting piece and forms a flow passage.
The filter heads are arranged on the gas-water distribution plate, the filter heads consist of filter caps, filter gaps and filter rods, and the filter rods are arranged on the gas-water distribution plate through rubber gaskets and threads, so that uniform distribution of water flow and gas at the bottom of the reactor can be realized, and meanwhile, the function of intercepting biological carriers can be achieved.
The filter screen meshes can be wedge-shaped, round holes, square holes and the like, the filter screen cleaning mode can be one or a combination of a plurality of ultrasonic cleaning, rotating brush cleaning, scraping plate cleaning, spraying flushing and the like, the purposes of adhering sludge cleaning, continuous sludge discharge and carrier loss prevention to the outlet filter screen are achieved, and the outlet water enters a circulating pipeline or a discharge system through a water outlet after passing through the filter screen.
In a fifth aspect, the present invention provides a sewage treatment method, including the steps of: introducing sewage to be treated into the device of claim 8 or 9, and sequentially passing through a feeding area, a water distribution area, a carrier area, a three-phase separation area and a water outlet area;
preferably, the COD value of the inflow water is 50 mg/L-15000 mg/L; and/or NO 3 Concentration of-N (NO in the present invention) 3 N means nitrate nitrogen, i.e. nitrate nitrogen) of 10 mg/L~3000mg/L。
As a specific embodiment of the invention, the ascending flow rate of the materials in the carrier zone is 10 m/h-100 m/h, preferably 20 m/h-70 m/h.
As a specific embodiment of the invention, the hydraulic retention time in the upflow expanded bed reactor is 1-48 h, preferably 5-20 h. In the present invention, the hydraulic retention time in the upflow expanded bed reactor refers to the retention time of wastewater in the reactor, which is a conventional parameter in the art.
As a specific embodiment of the invention, the upflow expanded bed reactor processes a total nitrogen load of 0.5. 0.5 kg/m 3 •d~10 kg/m 3 D, preferably 1 kg/m 3 •d~5 kg/m 3 •d。
As a specific embodiment of the invention, the expansion rate of the carrier in the carrier region is 1% -100%, preferably 10% -50%.
The denitrification carrier and the preparation method and the device have the following beneficial effects:
(1) The denitrification carrier has controllable density range and large specific surface area, controllable pore canal structure, high mechanical strength and long service life;
(2) The denitrification carrier has rough pore wall, easy attachment of denitrification flora, quick start of the reactor and high biological membrane content in the carrier area;
(3) The denitrification carrier is easy to fluidize, the flow state of the solid phase and the liquid phase is favorable for the contact and mass transfer of microorganisms and sewage, and the denitrification efficiency is high;
(4) The denitrification carrier biomembrane volume can realize self-balancing in operation, so that the periodic backwashing required by a conventional fixed bed is avoided, and the denitrification load is high;
(5) The anti-blocking filter head is adopted for uniform water distribution, so that the water distribution uniformity is improved, and the effective utilization rate of the carrier layer is increased;
(6) The device has small occupied area, stable operation and high denitrification load without separately arranging a sludge sedimentation tank.
Drawings
The invention will be described in further detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram of an apparatus of the present invention;
FIG. 2 is a schematic cross-sectional view of a filter head on a gas-water distribution plate according to the present invention;
in the drawings, the meaning of the reference numerals is as follows:
1. the device comprises a feeding area, 2 parts of a feeding pump, 3 parts of a water inlet, 4 parts of a gas-water distribution plate, 5 parts of a supporting layer, 6 parts of a carrier area, 7 parts of a water outlet area, 8 parts of a water collecting tank, 9 parts of a water outlet weir, 10 parts of a three-phase separator, 11 parts of a water outlet, 12 parts of a water outlet filter screen, 13 parts of a circulating pump, 14 parts of a cleaning system, 15 parts of a filter cap, 16 parts of a filter seam, 17 parts of a filter rod, 18 parts of a rubber pad.
Detailed Description
In order that the invention may be more readily understood, the invention will be described in detail below with reference to the following examples and the accompanying drawings, which are given by way of illustration only and are not limiting the scope of application of the invention.
As shown in fig. 1, the process flow for treating wastewater by adopting the device of the invention is as follows:
step one, a feeding zone 1 is connected with a feeding pump 2, circulating water at a water outlet 11 of an anoxic fluidized bed enters a circulating pump 13, water discharged from the circulating pump 13 and water discharged from the feeding pump 2 are mixed and then enter an expanded bed reactor through a bottom water inlet 3, water is distributed through a gas-water distribution plate 4 and then enters a carrier zone 6 through a supporting layer 5, and carrier particles in the expanded bed float along with water flow under the action of upward flowing circulating water flow, so that carriers in the carrier zone 6 are in an expanded state.
Step two, circulating water flow enters the water outlet area 7 after passing through the carrier area 6, the cross section area of the water outlet area 7 is larger than that of the carrier area 6, the rising flow speed of the water flow is reduced, fine carrier particles carried by the circulating water flow in the carrier area are intercepted by the three-phase separator 10 and are settled back to the carrier area 6 after the flow speed of the water flow is reduced, and the fine carrier is prevented from being carried out of the fluidized bed by the water flow.
And thirdly, the gas produced by the reactor can be led out from the upper port of the three-phase separator 10, water flows reach the water outlet area and then are collected in the water collecting tank 8, overflowed from the water outlet 11 through the water outlet weir 9, intercepted and filtered by the water outlet filter screen 12 and then enter the circulating pump 13, and as the circulating water contains biodegradable matrixes, microbial films grow on the fine particle carriers in the carrier area for denitrification reaction, organic matters and total nitrogen are removed, and the residual water overflows into the drain pipe discharging system through the liquid level height difference. After the reaction is completed, the entire reactor may be purged by a purge system 14.
As can be seen from fig. 2, the gas-water distribution plate 4 is fixedly provided with a filter rod 17 and a filter cap 15 which are in one-to-one correspondence, the filter cap 15 is provided with a filter slit 16, and a rubber pad 18 is arranged between the filter rod 17 and the filter cap 15.
The test methods or criteria used in the following examples and comparative examples are as follows:
(1) Density tester: CPA225D, density accessory YDK01, sartorius company, germany. The testing method comprises the following steps: and (3) using a density accessory of the Satorius balance, and obtaining the apparent density of the thermoplastic resin porous foam body by using a drainage method according to GB/T6343-2009 standard test.
(2) Scanning electron microscope: XL-30, FEI company, USA. The testing method comprises the following steps: quenching the foaming material by liquid nitrogen, spraying metal on the section, and observing the cell structure inside the foaming material by adopting a Scanning Electron Microscope (SEM).
(3) Open-close aperture ratio tester: ULTRAFOAM 1200e, quantachrome instruments, inc., U.S.A.. The testing method comprises the following steps: according to GB/T10799-2008.
(4) Specific surface area tester: ASAP2020Plus specific surface area tester, michael Ratike instruments, inc., USA. The testing method comprises the following steps: according to GB/T19587-2017.
(5) COD concentration test: COD tester, DR-890 of Hash company in America. The testing method comprises the following steps: and (5) performing according to HJ 828-2017.
（6）NO 3 -N concentration test: ion chromatograph, ICS 5000, available from Dynam, USA. The testing method comprises the following steps: according to HJ 84-2016.
(7) Carrier layer expansion ratio: the rest height of the carrier layer is H 0 The carrier layer has a height H after expansion 1 The carrier layer expansion ratio was (H 1 - H 0 )/H 0 。
(8) Carrier layer up flow rate: the flow rate of rising water flow in the reactor, the flow rate of the reactor is Q, the diameter of the reactor is d, and the carrier is thatThe body layer rising flow rate is Q/(pi.d) 2 /4)。
The sources of materials in the following examples and comparative examples are as follows:
ternary copolymer microspheres SYXQ101, 102, 103, 104, 105: the ternary polymerization microsphere is a self-made ternary polymerization microsphere, and the preparation method comprises the following steps: in inert atmosphere, maleic anhydride, alpha-methyl styrene, styrene and an initiator are dissolved in an organic medium to form a homogeneous solution, and after the homogeneous solution is polymerized to obtain copolymer emulsion suspension, the terpolymer microsphere is obtained by centrifugal separation. The dosage of maleic anhydride and the molar ratio of styrene to alpha-methyl styrene are regulated and controlled, the self-stable dispersion of a polymerization system is realized, the prepared polymer is microsphere with excellent uniformity, no additives such as a stabilizer, a precipitant and the like are required to be added in the polymerization process, and the obtained copolymer microsphere has the characteristics of clean surface, good dispersibility in a medium and no aggregation. The initiator is an organic peroxide and/or azo compound. The organic medium is selected from organic acid alkyl ester.
Other commercial products are commercially available without any particular description.
Example 1
Taking a certain industrial wastewater with COD concentration of 3000mg/L and NO 3 The N concentration is 750 mg/L and the COD treatment load is 12.1 kg/m 3 ·d，NO 3 N treatment load of 3.2 kg/m 3 D. The reactor process parameters range as follows:
1. preparing a denitrification carrier:
(1) The polymerization temperature of the synthesized ternary polymerization microsphere SYXQ101 is 60 ℃, the polymerization time is 5 hours, and the average particle size of the copolymer microsphere is 1200nm. Total molar amount of each structural unit in the polymer: the molar content of maleic anhydride structural units was 50%, the molar content of styrene structural units was 10%, and the molar content of α -methylstyrene structural units was 40%. The molar ratio of styrene to alpha-methylstyrene was 1:9.
(2) Mixing HDPE YGH041 with filler SYXQ101, antioxidant 1010 and antioxidant 168 according to the weight ratio of 100:10:0.2:0.1, adding the composition into a feeder of a double-screw extruder, feeding the materials into the double-screw extruder through the feeder, keeping the temperature of the screw at 180-210 ℃ in the processing process, melting and mixing uniformly through the screw, drawing, extruding, granulating at the granulating speed of 250rpm, and drying at 80 ℃ to obtain material particles with rough surfaces and smooth sections.
(3) Heating the supercritical fluid treatment device to 145 ℃, putting the material particles prepared in the step (2) into the supercritical fluid treatment device, and sealing a furnace chamber. Introducing 10MPa nitrogen into the furnace chamber, and allowing supercritical carbon dioxide to diffuse into the matrix at 145 ℃ and 10 MPa. After saturation for 20min, the diffusion balance is achieved, the pressure in the furnace chamber is reduced to 4MPa in 2 min through a pressure relief valve, then the furnace chamber is opened for pressure relief foaming, cooling and shaping, and the denitrification carrier is obtained.
The denitrification carrier has a rough appearance, a large number of pores can be observed on a section, the average particle diameter is 2.5mm, and the specific surface area is 32.68m 2 Per gram, apparent density of 0.60g/cm 3 The closed porosity was 34.7%.
2. Anoxic expanded bed denitrification reaction:
(1) The inlet water and the circulating water are mixed and then enter an anoxic expansion bed, after being distributed by the gas-water distribution plate 4, the mixture enters the carrier zone 6 through the supporting layer 5, and the filling volume ratio of the denitrification carrier in the carrier zone 6 is 61 percent.
(2) The rising flow rate of the carrier area 6 is 30m/h, the expansion rate of the corresponding carrier layer is 10%, organic matters and total nitrogen in the wastewater are removed through denitrification under the action of a carrier biological film, and the hydraulic retention time is 12 h.
(3) The COD in the treated water can be reduced from 3000mg/L to below 110 mg/L, NO 3 The N can be reduced from 700 mg/L to below 15 mg/L, the COD removal rate reaches over 96 percent, and NO 3 The removal rate of N reaches 98 percent.
Example two
Taking industrial wastewater with COD concentration of 400 mg/L and NO 3 The concentration of N is 100 mg/L and the COD treatment load is 8.0 kg/m 3 ·d，NO 3 N treatment load of 2.1 kg/m 3 D. The reactor process parameters range as follows:
1. preparing a denitrification carrier:
(1) The polymerization temperature of the synthesized ternary polymerization microsphere SYXQ102 is 70 ℃, the polymerization time is 5 hours, and the average particle size of the copolymer microsphere is 1500nm. Total molar amount of each structural unit in the polymer: the molar content of maleic anhydride structural units was 48%, the molar content of styrene structural units was 12%, and the molar content of α -methylstyrene structural units was 40%. The molar ratio of styrene to alpha-methylstyrene was 2:8.
(2) After mixing the homo-polypropylene T30s with the filler SYXQ102, the antioxidant 1010 and the antioxidant 168 according to the weight ratio of 100:15:0.2:0.1, adding the composition into a feeder of a double-screw extruder, feeding the materials into the double-screw extruder through the feeder, keeping the temperature of the screw at 160-200 ℃ in the processing process, uniformly mixing by melting the screw, extruding by a draw bar, granulating at a granulating speed of 300rpm, and drying at 80 ℃ to obtain material particles with rough surfaces and smooth cut surfaces.
(3) Heating the supercritical fluid treatment device to 160 ℃, putting the material particles prepared in the step (2) into the supercritical fluid treatment device, and sealing a furnace chamber. Introducing 15MPa nitrogen into the furnace chamber, and allowing supercritical nitrogen to diffuse into the substrate at 160 ℃ and 15 MPa. After 15min of saturation, the diffusion balance is achieved, the pressure in the furnace chamber is reduced to 7MPa in 1 min through a pressure relief valve, the pressure is maintained for 10min and then reduced to 3MPa in 4 min, and then the furnace chamber is opened for pressure relief foaming, cooling and shaping, so that the denitrification carrier is obtained.
The denitrification carrier has a rough appearance, a large number of pores can be observed on a section, the average particle diameter is 2.1mm, and the specific surface area is 27.27m 2 Per gram, apparent density of 0.74g/cm 3 The closed porosity was 46.3%.
2. Anoxic expanded bed denitrification reaction:
(1) The inlet water and the circulating water are mixed and then enter an anoxic expansion bed, after being distributed by the gas-water distribution plate 4, the mixture enters the carrier zone 6 through the supporting layer 5, and the filling volume ratio of the denitrification carrier in the carrier zone 6 is 60 percent.
(2) The rising flow rate of the carrier zone 6 is 25m/h, the expansion rate of the corresponding carrier layer is 9%, organic matters and total nitrogen in the wastewater are removed through denitrification under the action of a carrier biological film, and the hydraulic retention time is 3 h.
(3) The COD in the treated water can be reduced from 400 mg/L to below 30 mg/L, NO 3 The N can be reduced from 100 mg/L to below 5 mg/L, the COD removal rate reaches more than 93 percent, and NO 3 The N removal rate reaches more than 95 percent.
Example III
Taking industrial wastewater with COD concentration of 6000 mg/L and NO 3 The N concentration was 1400 mg/L and the COD treatment load was 24.3 kg/m 3 ·d，NO 3 N treatment load of 6.0 kg/m 3 D. The reactor process parameters range as follows:
1. preparing a denitrification carrier:
(1) The polymerization temperature of the synthesized ternary polymerization microsphere SYXQ103 is 80 ℃, the polymerization time is 5 hours, and the average particle size of the copolymer microsphere is 1600nm. Total molar amount of each structural unit in the polymer: the molar content of maleic anhydride structural units was 51%, the molar content of styrene structural units was 15%, and the molar content of α -methylstyrene structural units was 34%. The molar ratio of styrene to alpha-methylstyrene was 3:7.
(2) Mixing LDPE LD100AC with filler SYXQ103, antioxidant 1010 and antioxidant 168 according to the weight ratio of 100:5:0.2:0.1, adding the composition into a feeder of a double-screw extruder, feeding the materials into the double-screw extruder through the feeder, maintaining the temperature of the screw at 160-200 ℃ in the processing process, melting and mixing the materials uniformly through the screw, extruding the materials by drawing bars, granulating at a granulating speed of 210rpm, and drying at 80 ℃ to obtain material particles with rough surfaces and smooth sections.
(3) Heating the supercritical fluid treatment device to 140 ℃, putting the material particles prepared in the step (2) into the supercritical fluid treatment device, and sealing a furnace chamber. Introducing 7.5MPa of carbon dioxide into the furnace chamber, so that the supercritical carbon dioxide is diffused into the matrix under the conditions of 140 ℃ and 7.5 MPa. And after saturation for 25min, reaching diffusion balance, opening a furnace chamber to release pressure for foaming, and cooling and shaping to obtain the denitrification carrier.
The denitrification carrier has a rough appearance, a large number of pores can be observed on a section, the average particle diameter is 2.6mm, and the specific surface area is 23.19m 2 Per gram, apparent density of 0.50g/cm 3 The closed porosity was 25.6%.
2. Anoxic expanded bed denitrification reaction:
(1) The inlet water and the circulating water are mixed and then enter an anoxic expansion bed, after being distributed by the gas-water distribution plate 4, the mixture enters the carrier zone 6 through the supporting layer 5, and the filling volume ratio of the denitrification carrier in the carrier zone 6 is 65 percent.
(2) The rising flow rate of the carrier area 6 is 40m/h, the expansion rate of the corresponding carrier layer is 15%, organic matters and total nitrogen in the wastewater are removed through denitrification under the action of a carrier biological film, and the hydraulic retention time is 5 h.
(3) The COD in the treated water can be reduced from 6000 mg/L to 270-mg/L or less, NO 3 The N can be reduced from 1400 mg/L to below 28 mg/L, the COD removal rate reaches over 96 percent, and NO 3 The removal rate of N reaches 98 percent.
Example IV
Taking industrial wastewater with COD concentration of 1250 mg/L and NO 3 The N concentration is 300 mg/L and the COD treatment load is 14.3 kg/m 3 ·d，NO 3 N treatment load of 3.5 kg/m 3 D. The reactor regulation and control process parameters range is as follows:
1. preparing a denitrification carrier:
(1) The polymerization temperature of the synthesized ternary polymerization microsphere SYXQ104 is 65 ℃, the polymerization time is 5 hours, and the average particle size of the copolymer microsphere is 1500nm. Total molar amount of each structural unit in the polymer: the molar content of maleic anhydride structural units was 49%, the molar content of styrene structural units was 20%, and the molar content of α -methylstyrene structural units was 31%. The molar ratio of styrene to alpha-methylstyrene was 4:6.
(2) After mixing high melt strength polypropylene HMS20Z with filler SYXQ104, antioxidant 1010 and antioxidant 168 according to the weight ratio of 100:8:0.2:0.1, adding the composition into a feeder of a double-screw extruder, feeding the materials into the double-screw extruder through the feeder, keeping the temperature of the screw at 160-200 ℃ in the processing process, uniformly mixing by melting the screw, extruding by a draw bar, granulating at a granulating speed of 275rpm, and drying at 80 ℃ to obtain material particles with rough surfaces and smooth sections.
(3) Heating the supercritical fluid treatment device to 163 ℃, putting the material particles prepared in the step (2) into the supercritical fluid treatment device, and sealing a furnace chamber. Introducing 15MPa nitrogen into the furnace chamber, and allowing supercritical nitrogen to diffuse into the substrate at 163 ℃ under 15 MPa. After 15min of saturation, the diffusion balance is achieved, the pressure in the furnace chamber is reduced to 6MPa in 3 min through a pressure relief valve, then the furnace chamber is opened for pressure relief foaming, and the denitrification carrier is obtained after cooling and shaping.
The denitrification carrier has a rough appearance, a large number of pores can be observed on a section, the average particle diameter is 2.1mm, and the specific surface area is 19.35m 2 Per gram, apparent density of 0.69g/cm 3 The closed porosity was 52.0%.
2. Anoxic expanded bed denitrification reaction:
(1) The inlet water and the circulating water are mixed and then enter an anoxic expansion bed, after being distributed by the gas-water distribution plate 4, the mixture enters the carrier zone 6 through the supporting layer 5, and the filling volume ratio of the denitrification carrier in the carrier zone 6 is 70 percent.
(2) The rising flow rate of the carrier area 6 is 45m/h, the expansion rate of the corresponding carrier layer is 18%, organic matters and total nitrogen in the wastewater are removed through denitrification under the action of a carrier biological film, and the hydraulic retention time is 10 h.
(3) The COD in the treated water can be reduced from 1250 mg/L to below 80 mg/L, NO 3 The N can be reduced from 300 mg/L to below 10 mg/L, the COD removal rate reaches over 94 percent, and NO 3 The removal rate of N reaches 97 percent.
Example five
Taking industrial wastewater with COD concentration of 8100 mg/L and NO 3 The N concentration was 2000 mg/L and the COD treatment load was 22.3kg/m 3 ·d，NO 3 N treatment load of 5.6kg/m 3 D. The technological parameters of the regulation and control of the biological membrane amount of the reactor are as follows:
1. preparing a denitrification carrier:
(1) The polymerization temperature of the synthesized ternary polymerization microsphere SYXQ105 is 75 ℃, the polymerization time is 3h, and the average particle size of the copolymer microsphere is 1400nm. Total molar amount of each structural unit in the polymer: the molar content of the maleic anhydride structural unit was 51%, the molar content of the styrene structural unit was 27%, and the molar content of the α -methylstyrene structural unit was 22%. The molar ratio of styrene to alpha-methylstyrene was 6:4.
(2) Mixing LD100AC, EVA V4110J, HMS Z, a filler SYXQ105, an antioxidant 1010 and an antioxidant 168 according to a weight ratio of 20:10:70:25:0.2:0.1, adding the composition into a feeder of a double-screw extruder, feeding the materials into the double-screw extruder through the feeder, keeping the temperature of the screw at 160-200 ℃ in the processing process, melting and mixing the materials uniformly through the screw, extruding the materials through a draw bar, granulating at a granulating speed of 275rpm, and drying at 80 ℃ to obtain material particles with rough surfaces and smooth sections.
(3) Heating the supercritical fluid treatment device to 158 ℃, putting the material particles prepared in the step (2) into the supercritical fluid treatment device, and sealing a furnace chamber. Introducing 8MPa of carbon dioxide into the furnace chamber, and then introducing nitrogen to enable the pressure to reach 18MPa. The supercritical mixed gas is diffused into the matrix at 158 ℃ and 18MPa. After saturation for 30min, the diffusion balance is achieved, the pressure in the furnace chamber is reduced to 4MPa in 2.5 min through a pressure relief valve, then the furnace chamber is opened for pressure relief foaming, and the denitrification carrier is obtained after cooling and shaping.
The denitrification carrier has a rough appearance, a large number of pores can be observed on a section, the average particle diameter is 2.3mm, and the specific surface area is 48.09m 2 Per gram, apparent density of 0.55g/cm 3 The closed porosity was 30.1%.
2. Anoxic expanded bed denitrification reaction:
(1) The inlet water and the circulating water are mixed and then enter an anoxic expansion bed, after being distributed by the gas-water distribution plate 4, the mixture enters the carrier zone 6 through the supporting layer 5, and the filling volume ratio of the denitrification carrier in the carrier zone 6 is 80 percent.
(2) The rising flow rate of the carrier zone 6 is 49m/h, the expansion rate of the corresponding carrier layer is 16%, organic matters and total nitrogen in the wastewater are removed through denitrification under the action of a carrier biological film, and the hydraulic retention time is 15 and h.
(3) The COD in the treated water can be reduced from 8100 mg/L to below 400 mg/L, NO 3 The N energy is reduced from 2000 mg/L to below 40 mg/L, the COD removal rate is over 95 percent, and NO 3 The removal rate of N reaches 98 percent.
Comparative example one
Taking a certain industrial wastewater with COD concentration of 3000mg/L and NO 3 -N concentrationThe degree of the wastewater is 750 mg/L, and the COD treatment load is 11.2 kg/m 3 ·d，NO 3 N treatment load of 3.2 kg/m 3 D. This was treated by the same apparatus and process flow as in example 1, but the carrier preparation step three was carried out by using a chemically foamed extrusion molded body. Mixing the material particles obtained in the second step of preparing the carrier and 4 parts of AC foaming agent (azodicarbonamide), adding into a single screw extruder, extruding into strip-shaped foam bodies from a front end nozzle of the extruder, and cutting the foam bodies to obtain carrier with an average particle size of 2.3mm and a specific surface area of 0.75m 2 Per g, apparent density of 0.88g/cm 3 The closed porosity was 69.6%. NO after anoxic expanded bed treatment 3 -N removal rate is 50%.
Comparative example two
Taking a certain industrial wastewater with COD concentration of 3000mg/L and NO 3 The N concentration was 750 mg/L and the COD treatment load was 11.2 kg/m 3 ·d，NO 3 N treatment load of 3.2 kg/m 3 D. This was treated by the same apparatus and process flow as in example 1, but the carrier preparation step three was carried out by using a chemically foamed extrusion molded body. Mixing the material particles prepared in the second step of carrier preparation and 6 parts of AC foaming agent, adding into a single screw extruder, extruding into strip-shaped foam bodies from a front end nozzle of the extruder, and cutting the foam bodies to obtain carrier with an average particle size of 2.3mm and a specific surface area of 5.11m 2 Per g, apparent density of 0.68g/cm 3 The closed porosity was 27.7%. NO after anoxic expanded bed treatment 3 The N removal rate was 60%.
Comparative example three
Taking a certain industrial wastewater with COD concentration of 3000mg/L and NO 3 The N concentration was 750 mg/L and the COD treatment load was 11.2 kg/m 3 ·d，NO 3 N treatment load of 3.2 kg/m 3 D. This was treated by the same apparatus and process flow as in example 1, but the carrier preparation step three was carried out by using a chemically foamed extrusion molded body. Mixing the material particles prepared in the second step of carrier preparation and 8 parts of AC foaming agent, adding into a single screw extruder, extruding into strip-shaped foam bodies from a front end nozzle of the extruder, and cutting the foam bodies to obtain carrier with an average particle size of 2.9mm and a specific surface area of 8.86m 2 Per g, apparent density of 0.43g/cm 3 The closed porosity was 15.1%. NO after anoxic expanded bed treatment 3 The N removal rate was 83%.
Comparative example four
Taking a certain industrial wastewater with COD concentration of 3000mg/L and NO 3 The N concentration was 750 mg/L and the COD treatment load was 11.2 kg/m 3 ·d，NO 3 N treatment load of 3.2 kg/m 3 D. The same apparatus and process flow as in example 1 were used to treat the same, but no filler was added in the first stage of carrier preparation, and the carrier obtained had an average particle diameter of 2.5mm and a specific surface area of 6.40m 2 Per g, apparent density of 0.58g/cm 3 The closed porosity was 38.2%. NO after anoxic expanded bed treatment 3 The N removal rate was 70%.
Comparative example five
Taking a certain industrial wastewater with COD concentration of 3000mg/L and NO 3 The N concentration was 750 mg/L and the COD treatment load was 11.2 kg/m 3 ·d，NO 3 N treatment load of 3.2 kg/m 3 D. The same equipment and process flow as in example 1 were used to treat the same, but the filler in the carrier preparation step was changed to talc powder, which was produced by DalianFuji mineral company and had a particle size distribution of 2 to 5. Mu.m, and the obtained carrier had an average particle size of 2.5mm and a specific surface area of 9.63m 2 Per gram, apparent density of 0.65g/cm 3 The closed porosity was 41.5%. NO after anoxic expanded bed treatment 3 -N removal rate was 85%.
It should be noted that the above-described embodiments are only for explaining the present invention and do not constitute any limitation of the present invention. The invention has been described with reference to exemplary embodiments, but it is understood that the words which have been used are words of description and illustration, rather than words of limitation. Modifications may be made to the invention as defined in the appended claims, and the invention may be modified without departing from the scope and spirit of the invention. Although the invention is described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, as the invention extends to all other means and applications which perform the same function.
Claims (18)
1. The denitrification carrier prepared from the denitrification carrier composition is characterized by comprising the following raw materials in parts by weight: 100 parts of a thermoplastic resin, based on 100 parts of the thermoplastic resin, further comprising:
0.05-1 part of antioxidant;
and 0.5-30 parts of filler;
the filler is maleic anhydride-styrene-alpha-methyl styrene ternary polymerization microsphere; based on the molar amount of the copolymer structural units in the filler, the molar content of the structural units provided by maleic anhydride is 48% -51%, the molar content of the structural units provided by styrene is 10% -45%, and the molar content of the structural units provided by alpha-methyl styrene is 10% -45%; the mol ratio of the styrene to the alpha-methyl styrene is 9:1-1:9; the average particle size of the ternary polymerization microsphere is 500-1600 nm;
the preparation method of the denitrification carrier comprises the following steps:
s101: mixing the raw materials, extruding, molding and granulating;
s102: drying the particles obtained in the step S101, and then introducing supercritical fluid to impregnate the particles to prepare a carrier;
s103: cooling the carrier prepared in the step S102, and then carrying out pore canal regulation;
the average grain diameter of the denitrification carrier is 1 mm-6 mm; and/or the specific surface area of the denitrification carrier is 1m 2 /g~100 m 2 /g; and/or the apparent density of the denitrification carrier is 0.20 g/cm 3 ~0.80 g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the And/or the closed pore ratio of the denitrification carrier is 1% -99%.
2. The denitrification carrier according to claim 1, wherein the antioxidant is 0.1 to 0.5 parts; the filler is 5-15 parts.
3. The denitrification carrier according to claim 1 or 2, wherein the thermoplastic resin is at least one selected from the group consisting of polyethylene resin, polypropylene resin, polyethylene compound resin, polystyrene resin, styrene-butadiene rubber resin, ABS resin and polyamide resin; and/or the antioxidant is at least selected from hindered phenolic antioxidants and/or phosphite antioxidants.
4. The denitrification carrier according to claim 1, wherein the thermoplastic resin is at least one selected from the group consisting of polypropylene, polyethylene, polybutylene and polypentene.
5. The denitrification carrier according to claim 3, wherein the antioxidant is a hindered phenol antioxidant and a phosphite antioxidant in a mass ratio of 1 (0.8-1.2).
6. The denitrification carrier according to claim 3, wherein the hindered phenol antioxidant is at least selected from the group consisting of antioxidant 1010, antioxidant 1076, antioxidant 245 and antioxidant 246; and/or the phosphite antioxidant is at least selected from triphenyl phosphate, trimethyl phosphate, and antioxidant 168.
7. The denitrification carrier according to claim 1, wherein the average particle diameter of the ternary polymerization microsphere is 800nm to 1500nm.
8. The denitrification carrier according to claim 1, wherein the denitrification carrier has an average particle diameter of 2mm to 2.5 mm; and/or the specific surface area of the denitrification carrier is 10m 2 /g~60 m 2 /g; and/or the apparent density of the denitrification carrier is 0.45 g/cm 3 ~0.75 g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the And/or the closed pore ratio of the denitrification carrier is 25% -60%.
9. The method for preparing a denitrification carrier according to any one of claims 1 to 8, comprising the steps of:
s101: mixing the raw materials, extruding, molding and granulating;
s102: drying the particles obtained in the step S101, and then introducing supercritical fluid to impregnate the particles to prepare a carrier;
s103: cooling the carrier prepared in the step S102, and then carrying out pore canal regulation;
in the step S101, the extrusion temperature is 170-230 ℃; and/or the dicing speed is 100 rpm to 500 rpm.
10. The method for preparing a denitrification carrier according to claim 9, wherein the extrusion temperature is 180 ℃ to 200 ℃; and/or the dicing speed is 200 rpm to 300 rpm.
11. The method for preparing a denitrification carrier according to claim 9, wherein in the step S102, the impregnation temperature of the supercritical fluid is 130 ℃ to 180 ℃; and/or the number of the groups of groups,
the impregnation working pressure of the supercritical fluid is 1.0-25.0 MPa; and/or the number of the groups of groups,
the soaking time is 1 min-1 h; and/or the number of the groups of groups,
after the supercritical fluid impregnation is completed, one-time pressure relief is adopted in pressure relief, and the pressure relief speed is 0.1-30 MPa/min; and/or the number of the groups of groups,
after the supercritical fluid impregnation is completed, multiple segmented pressure relief is adopted in pressure relief, and the pressure relief speed of each segment is 1-30 MPa/min.
12. The method for preparing a denitrification carrier according to claim 11, wherein the impregnation temperature of the supercritical fluid is 140 ℃ to 165 ℃; and/or the number of the groups of groups,
the impregnation working pressure of the supercritical fluid is 7.3-15.0 MPa; and/or the number of the groups of groups,
the soaking time is 10-30 min; and/or the number of the groups of groups,
after the supercritical fluid impregnation is completed, one-time pressure relief is adopted in pressure relief, and the pressure relief speed is 1-10 MPa/min; and/or the number of the groups of groups,
after the supercritical fluid impregnation is completed, multiple segmented pressure relief is adopted in pressure relief, and the pressure relief speed of each segment is 3-15 MPa/min.
13. An apparatus packed with the denitrification carrier according to any one of claims 1 to 8.
14. The apparatus of claim 13, comprising an upflow expanded bed reactor comprising, in order from bottom to top, a feed zone, a water distribution zone, a carrier zone, a three-phase separation zone, and a water outlet zone, the carrier zone being packed with a denitrification carrier; and/or, the height-to-diameter ratio of the upflow expanded bed reactor is (1-8): 1.
15. the apparatus of claim 14, wherein the loading volume of the denitrification carrier is 20% -80% of the volume of the carrier zone;
and/or, the height-to-diameter ratio of the upflow expanded bed reactor is (2-4): 1.
16. the sewage treatment method is characterized by comprising the following steps of: introducing sewage to be treated into the device of any one of claims 14-15, and sequentially passing through a feeding area, a water distribution area, a carrier area, a three-phase separation area and a water outlet area.
17. The method of claim 16, wherein the COD value of the incoming water is 50 mg/L to 15000 mg/L; and/or NO 3 The concentration of the N is 10 mg/L to 3000mg/L; and/or the number of the groups of groups,
the rising flow rate of the materials in the carrier area is 10 m/h-100 m/h; and/or the number of the groups of groups,
the hydraulic retention time in the upflow expanded bed reactor is 1-48 h; and/or the number of the groups of groups,
the upflow expanded bed reactor processes a total nitrogen load of 0.5. 0.5 kg/m 3 •d~10 kg/m 3 D; and/or the number of the groups of groups,
the expansion rate of the carrier in the carrier region is 1% -100%.
18. The method of claim 17, wherein the ascending flow rate of material in the carrier zone is 20 m/h to 70 m/h; and/or the number of the groups of groups,
the hydraulic retention time in the upflow expanded bed reactor is 5-20 h; and/or the number of the groups of groups,
the total nitrogen load of the upflow expanded bed reactor treatment is 1 kg/m 3 •d~5 kg/m 3 D; and/or the number of the groups of groups,
the expansion rate of the carrier in the carrier region is 10% -50%.
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