CN117285187A - Advanced treatment method and system for coal chemical wastewater - Google Patents
Advanced treatment method and system for coal chemical wastewater Download PDFInfo
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- CN117285187A CN117285187A CN202311264616.5A CN202311264616A CN117285187A CN 117285187 A CN117285187 A CN 117285187A CN 202311264616 A CN202311264616 A CN 202311264616A CN 117285187 A CN117285187 A CN 117285187A
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- 239000002351 wastewater Substances 0.000 title claims abstract description 228
- 239000000126 substance Substances 0.000 title claims abstract description 47
- 239000003245 coal Substances 0.000 title claims abstract description 45
- 238000000034 method Methods 0.000 title claims abstract description 37
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims abstract description 152
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- 239000012528 membrane Substances 0.000 claims abstract description 68
- 238000001556 precipitation Methods 0.000 claims abstract description 41
- 238000005189 flocculation Methods 0.000 claims abstract description 37
- 230000016615 flocculation Effects 0.000 claims abstract description 37
- 238000000108 ultra-filtration Methods 0.000 claims abstract description 37
- 238000005345 coagulation Methods 0.000 claims abstract description 26
- 230000015271 coagulation Effects 0.000 claims abstract description 26
- 238000010992 reflux Methods 0.000 claims abstract description 20
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 32
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 29
- 239000000701 coagulant Substances 0.000 claims description 11
- 239000007788 liquid Substances 0.000 claims description 11
- 238000001471 micro-filtration Methods 0.000 claims description 9
- 229920002401 polyacrylamide Polymers 0.000 claims description 8
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 claims description 4
- 150000002505 iron Chemical class 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims 1
- 238000004065 wastewater treatment Methods 0.000 abstract description 4
- 239000010842 industrial wastewater Substances 0.000 abstract description 2
- 239000010802 sludge Substances 0.000 description 22
- 238000001223 reverse osmosis Methods 0.000 description 14
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- 238000007872 degassing Methods 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 230000002195 synergetic effect Effects 0.000 description 3
- SIKJAQJRHWYJAI-UHFFFAOYSA-N Indole Chemical compound C1=CC=C2NC=CC2=C1 SIKJAQJRHWYJAI-UHFFFAOYSA-N 0.000 description 2
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 238000006065 biodegradation reaction Methods 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical group Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 2
- 239000005416 organic matter Substances 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 238000006385 ozonation reaction Methods 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229940037003 alum Drugs 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical group [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005842 biochemical reaction Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
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- 238000010586 diagram Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 125000000623 heterocyclic group Chemical group 0.000 description 1
- ARYKTOJCZLAFIS-UHFFFAOYSA-N hydrogen peroxide;ozone Chemical compound OO.[O-][O+]=O ARYKTOJCZLAFIS-UHFFFAOYSA-N 0.000 description 1
- PZOUSPYUWWUPPK-UHFFFAOYSA-N indole Natural products CC1=CC=CC2=C1C=CN2 PZOUSPYUWWUPPK-UHFFFAOYSA-N 0.000 description 1
- RKJUIXBNRJVNHR-UHFFFAOYSA-N indolenine Natural products C1=CC=C2CC=NC2=C1 RKJUIXBNRJVNHR-UHFFFAOYSA-N 0.000 description 1
- 229910017053 inorganic salt Inorganic materials 0.000 description 1
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 1
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000011112 process operation Methods 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003911 water pollution Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5281—Installations for water purification using chemical agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/722—Oxidation by peroxides
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F2001/007—Processes including a sedimentation step
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/08—Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD]
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/11—Turbidity
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2305/00—Use of specific compounds during water treatment
- C02F2305/02—Specific form of oxidant
- C02F2305/023—Reactive oxygen species, singlet oxygen, OH radical
-
- 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
- C02F3/02—Aerobic processes
- C02F3/12—Activated sludge processes
- C02F3/1236—Particular type of activated sludge installations
- C02F3/1268—Membrane bioreactor systems
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- 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
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- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
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- Water Supply & Treatment (AREA)
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- Organic Chemistry (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
Abstract
The invention relates to the technical field of industrial wastewater treatment, and discloses a method and a system for advanced treatment of coal chemical wastewater, wherein the method comprises the following steps: (1) Sequentially carrying out coagulation, flocculation and precipitation treatment on the biochemical-treated coal chemical wastewater; (2) Sequentially conveying the obtained first wastewater to a front ozone oxidation device and an MBR reactor for treatment, conveying the obtained wastewater a to a rear ozone oxidation device for treatment according to a reflux ratio of 0-60%, and then returning to the MBR reactor; or sequentially conveying the first wastewater to a front ozone oxidation device, a rear ozone oxidation device and an MBR reactor for treatment; (3) The wastewater from the MBR reactor is sent to an ultrafiltration device for treatment. The method provided by the invention can effectively remove the refractory soluble organic matters and the insoluble organic matters in the wastewater, thereby effectively reducing the pollution problem of the RO membrane, and simultaneously has low operation cost and good economy.
Description
Technical Field
The invention relates to the technical field of industrial wastewater treatment, in particular to a method and a system for advanced treatment of coal chemical wastewater.
Background
In the recycling process of the coal chemical wastewater, a process taking a reverse osmosis technology as a core is widely adopted by coal chemical enterprises, however, membrane pollution is the biggest problem in the application process of the Reverse Osmosis (RO) technology, and the membrane pollution type mainly comprises organic pollution, inorganic salt deposition pollution, particle and colloid pollution, biological pollution and the like, wherein the organic pollution accounts for 60-80%, and is the most common and difficult problem in the current membrane pollution type.
The prior coal chemical wastewater is usually subjected to pretreatment, biochemical treatment and advanced treatment before entering a reverse osmosis membrane system, and most of organic matters in the wastewater can be removed after pretreatment and biochemical treatment, but some refractory organic matters (such as pyridine, indole, quinoline and heterocyclic matters) cannot be effectively removed. Chemical Oxygen Demand (COD) refers to the amount of oxidant consumed when a water sample is treated with a strong oxidant under certain conditions, and can be used to represent the total amount of organic matter in the wastewater, with greater COD values indicating greater levels of water pollution. The organic matters in the wastewater are mainly divided into dissolubility and non-dissolubility, the existing advanced treatment process generally adopts technologies such as flocculation precipitation, filtration and advanced oxidation treatment, wherein nondegradable and non-dissoluble COD can be basically removed through the flocculation precipitation or the filtration, and the advanced oxidation treatment technology is generally adopted for removing nondegradable and soluble COD, but has limited treatment effect, so that the soluble COD pollutants in the wastewater cannot be degraded to the limit, nondegradable and soluble COD still remains in the wastewater after the advanced treatment, and reverse osmosis membranes in the subsequent reuse water process are easy to be polluted.
Disclosure of Invention
The invention aims to solve the problem of reverse osmosis membrane pollution caused by poor removal capability of nondegradable dissolved COD in a coal chemical wastewater advanced treatment method in the prior art, and provides a coal chemical wastewater advanced treatment method and a system.
In order to achieve the above object, the present invention provides a method for advanced treatment of coal chemical wastewater, comprising the steps of:
(1) Sequentially carrying out coagulation, flocculation and precipitation treatment on the biochemical-treated coal chemical wastewater to obtain first wastewater;
(2) Sequentially conveying the first wastewater to a front ozone oxidation device and an MBR reactor for treatment, conveying the obtained wastewater a to a rear ozone oxidation device for treatment according to a reflux ratio of 0-60%, and then returning to the MBR reactor;
or sequentially conveying the first wastewater to a front ozone oxidation device, a rear ozone oxidation device and an MBR reactor for treatment;
(3) Delivering the wastewater from the MBR reactor to an ultrafiltration device for treatment;
wherein, in the MBR reactor, the used membrane is a microfiltration membrane;
in the front ozone oxidation device, the first wastewater and ozone are subjected to oxidation reaction;
in the post-ozone oxidation device, the wastewater is subjected to oxidation reaction with ozone and hydrogen peroxide.
Preferably, the step (2) specifically includes:
when COD in the first wastewater is less than 100mg/L, sequentially conveying the first wastewater to a front ozone oxidation device and an MBR reactor for treatment;
when COD in the first wastewater is more than or equal to 100mg/L and less than 300mg/L, sequentially conveying the first wastewater to a front ozone oxidation device and an MBR reactor for treatment, conveying the obtained wastewater a to a rear ozone oxidation device for treatment according to a reflux ratio of not more than 60%, and then returning to the MBR reactor;
when the COD in the first wastewater is more than or equal to 300mg/L, the first wastewater is sequentially conveyed to a front ozone oxidation device, a rear ozone oxidation device and an MBR reactor for treatment.
Preferably, in the step (1), the COD concentration in the biochemical treatment coal chemical wastewater is 100-500 mg/L, and the suspended matter concentration is more than 40 mg/L.
Preferably, in the step (1), the coagulant used for coagulation is aluminum salt or iron salt.
Preferably, in the step (1), the solid-to-liquid ratio of the coagulant to the wastewater to be treated is 30-80 mg/L during coagulation.
Preferably, in step (1), the flocculant used in the flocculation is polyacrylamide.
Preferably, in the step (1), the solid-liquid ratio of the flocculant to the wastewater to be treated is 0.5-2 mg/L when flocculation is performed.
Preferably, in the MBR reactor, the wastewater to be treated is mixed with activated carbon.
Preferably, in the MBR reactor, the solid-to-liquid ratio of the activated carbon to the wastewater to be treated is 0.5-1.0 g/L.
The invention provides a system for advanced treatment of coal chemical wastewater, which comprises a high-efficiency precipitation device, a front ozone oxidation device, a rear ozone oxidation device, an MBR reactor and an ultrafiltration device which are sequentially connected, wherein a water outlet of the MBR reactor is connected with a water inlet of the rear ozone oxidation device, a water outlet of the front ozone oxidation device is connected with a water inlet of the MBR reactor, a membrane component is arranged in the MBR reactor, and the membrane component is a microfiltration membrane;
delivering the biochemical-treated coal chemical wastewater into the efficient precipitation device to sequentially perform coagulation, flocculation and precipitation treatment;
the first wastewater from the high-efficiency precipitation device is conveyed to the front ozone oxidation device to perform oxidation reaction with ozone, then conveyed to the MBR reactor to be treated, the obtained wastewater a is conveyed to the rear ozone oxidation device to perform oxidation reaction with ozone and hydrogen peroxide according to a reflux ratio of 0-60%, then returned to the MBR reactor,
or, conveying the first wastewater from the high-efficiency precipitation device to the front ozone oxidation device to perform oxidation reaction with ozone, then conveying the first wastewater to the rear ozone oxidation device to perform oxidation reaction with ozone and hydrogen peroxide, and then conveying the first wastewater to the MBR reactor to perform treatment;
and conveying the wastewater from the MBR reactor to the ultrafiltration device for treatment.
According to the technical scheme provided by the invention, the biochemical treatment of the coal chemical wastewater is subjected to coagulation, flocculation and precipitation, then an MBR microfiltration membrane is adopted to cooperate with an ozone process, and finally an ultrafiltration membrane is used for treatment, and the nondegradable dissolved COD and insoluble COD in the wastewater can be effectively removed under the combined action of the processes, so that the COD in the wastewater is comprehensively and thoroughly removed, the pollution problem of the RO membrane is effectively reduced, and the service life of the RO membrane is prolonged; meanwhile, the invention adopts the flexible operation mode adjustment and configuration of the combined process of the front ozone oxidation device, the cooperative rear ozone oxidation device and the MBR reactor, thereby ensuring the wastewater treatment effect and simultaneously minimizing the operation cost.
Drawings
FIG. 1 is a schematic diagram of a system for advanced treatment of coal chemical wastewater.
Description of the reference numerals
1-a high-efficiency precipitation device; 2-a front ozone oxidation device; 3-a post ozone oxidation unit; a 4-MBR reactor; 5-ultrafiltration device.
Detailed Description
The following describes specific embodiments of the present invention in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
After pretreatment, biochemical treatment and advanced treatment of the existing coal chemical wastewater, insoluble organic matters can be effectively removed basically, but partial refractory soluble COD is difficult to remove, and after the soluble COD enters a reverse osmosis system of a recycling process, the soluble COD is adsorbed on the surface of a membrane to form an organic matter adsorption layer, so that the performance of the reverse osmosis membrane can be quickly degraded, the water flux of the reverse osmosis membrane is quickly and greatly reduced, and the membrane polluted by the organic matters is difficult to clean and almost irreversible.
In view of this, the present invention provides a method for advanced treatment of wastewater in coal chemical industry, please refer to fig. 1, which includes the following steps:
(1) Sequentially carrying out coagulation, flocculation and precipitation treatment on the biochemical-treated coal chemical wastewater to obtain first wastewater;
(2) The first wastewater is sequentially conveyed to a front ozone oxidation device 2 and an MBR reactor 4 for treatment, the obtained wastewater a is conveyed to a rear ozone oxidation device 3 for treatment according to a reflux ratio of 0-60%, and then the wastewater a is returned to the MBR reactor 4;
or sequentially conveying the first wastewater to a front ozone oxidation device 2, a rear ozone oxidation device 3 and an MBR reactor 4 for treatment;
(3) Delivering the wastewater from the MBR reactor 4 to an ultrafiltration device 5 for treatment;
wherein, in the MBR reactor 4, the membrane used is a microfiltration membrane;
in the front ozone oxidation device 2, the first wastewater is subjected to an oxidation reaction with ozone;
in the post-ozone oxidation device 3, the wastewater is subjected to oxidation reaction with ozone and hydrogen peroxide.
In the method provided by the invention, the processes of the microfiltration membrane (MBR 4) and the ultrafiltration membrane (ultrafiltration device 5) are adopted, and simultaneously the coagulation, flocculation, precipitation treatment, pre-ozone oxidation treatment and post-ozone oxidation treatment are cooperated, so that not only can the nondegradable non-soluble organic matters in the coal chemical wastewater be effectively removed, but also the nondegradable soluble organic matters in the coal chemical wastewater can be effectively removed, the COD concentration is greatly reduced after the wastewater is subjected to advanced treatment, the RO membrane pollution problem is effectively reduced, and the service life of the RO membrane is prolonged.
In the invention, advanced treatment is carried out on the coal chemical wastewater after biochemical treatment. It is understood that the pretreatment is also performed before the biochemical treatment, and thus, the biochemical-treated coal chemical wastewater actually refers to the pretreated and biochemical-treated coal chemical wastewater. After pretreatment and biochemical treatment, the wastewater in the coal chemical industry still contains pollutants such as higher COD and the like. The invention is not limited to specific types and contents of pollutants in the biochemical-treated coal chemical wastewater, and in a specific implementation manner, in the step (1), the COD concentration of the biochemical-treated coal chemical wastewater is 100-500 mg/L, and the suspended matter concentration is more than 40 mg/L.
The present invention is not limited to the specific type of the front ozone oxidation apparatus 2 and the rear ozone oxidation apparatus 3, as long as a reaction space can be provided, and a reaction tower, a reaction tank, etc. are preferable for easy operation. That is, the front ozone oxidation device 2 is a front ozone oxidation tank, and the rear ozone oxidation device 3 is a rear ozone oxidation tank.
In the pre-ozone oxidation device 2, the first wastewater and ozone are subjected to oxidation reaction, part of organic matters in the coal chemical wastewater are removed by oxidation through hydroxyl radicals generated by the ozone, meanwhile, the organic matters difficult to biodegrade can be converted into small-molecular organic matters easy to biodegrade, and the biodegradability of the wastewater is improved.
In a specific embodiment, the front ozone oxidation device 2 is composed of an ozone contact area and an ozone degassing area, wherein the effluent of the efficient precipitation device 1 sequentially enters the ozone contact area, the ozone degassing area and the MBR reactor 4. The ozone contact area is formed by connecting 2-3 sections of contact chambers in series and is separated by a vertical guide baffle plate, each section of contact chamber is composed of a gas distribution area and a subsequent reaction area and is separated by the vertical guide baffle plate, an ozone microporous aeration disc is arranged at the bottom of the gas distribution area, ozone gas diffuses into water through the aeration disc, and the ozone adding amount is reduced by 30-40% according to the COD concentration of sewage and 1.5-2.5 kg O 3 And (3) removing kg COD, wherein the gas distribution amount of the first gas distribution area accounts for 40-60% of the total ozone amount, the total residence time of the contact area is not less than 45min, and the effective water depth is not less than 6.0m. The effluent from the contact zone enters an ozone degassing zone through a vertical guide plate, and stays for not less than 30min so as to remove residual ozone in the wastewater and avoid the damage of the residual ozone to the subsequent MBR reactor 4.
In the present invention, the structure of the rear ozone oxidation device 3 is similar to that of the front ozone oxidation device 2, but the rear ozone oxidation device 3 is added with hydrogen peroxide (H 2 O 2 ) Due to addition of H 2 O 2 Can induce O 3 More hydroxyl free radicals with stronger oxidizing ability are generated, and the synergistic pole of the hydroxyl free radicals and the synergistic pole greatly improves the oxidizing effect. Preferably, the total residence time of the ozone contact zone in the post-ozone oxidation unit 3 is controlled to be not less than 60 minutes.
In order to cope with the complex condition of the actual operation condition and increase the flexibility of the process operation, in the invention, the step (2) adopts the three-stage process flexible combination and the multifunctional configuration of the cooperative treatment of the front ozone oxidation device 2, the MBR reactor 4 and the rear ozone oxidation device 3, and the operation cost can be minimized while ensuring the wastewater treatment effect. In a preferred embodiment, the present combined process operates in three ways:
(1) when COD in the first wastewater is less than 100mg/L, the first wastewater is sequentially conveyed to the pre-ozone oxidation device 2 and the MBR reactor 4 for treatment.
Specifically, when the COD of the first wastewater is less than 100mg/L, the first wastewater is firstly conveyed into the front ozone oxidation device 2, macromolecule, annular and other refractory organic matters in the wastewater are subjected to ring opening and chain breaking by utilizing ozone generated by the front ozone oxidation device 2, the biodegradability of the wastewater is improved, then the wastewater enters the MBR reactor 4, and the organic matters in the wastewater are removed by utilizing the biological degradation of activated sludge and the adsorption dual action of activated carbon in the MBR reactor 4.
(2) When COD in the first wastewater is more than or equal to 100mg/L and less than 300mg/L, the first wastewater is sequentially conveyed to the front ozone oxidation device 2 and the MBR reactor 4 for treatment, the obtained wastewater a is conveyed to the rear ozone oxidation device 3 for treatment according to a reflux ratio of not more than 60%, and then the wastewater a is returned to the MBR reactor 4.
Preferably, the reflux ratio of the wastewater a to the post-ozone oxidation device 3 is 20-60%.
Specifically, when COD in the first wastewater is more than or equal to 100mg/L and is less than 300mg/L, the first wastewater is firstly conveyed to the front ozone oxidation device 2, macromolecule, annular and other refractory organic matters in the wastewater are subjected to ring opening and chain breaking by utilizing ozone generated by the front ozone oxidation device 2, the biodegradability of the wastewater is improved, then the wastewater enters the MBR reactor 4, the organic matters in the wastewater are removed by utilizing the double actions of activated sludge biodegradation and activated carbon adsorption in the MBR reactor 4, the wastewater a obtained after the treatment of the MBR reactor 4 is conveyed to the rear ozone oxidation device 3 for synergistic oxidation according to the reflux ratio of 20-60%, the oxidation degradation effect of the rear ozone oxidation device 3 is enhanced by utilizing the ozone-hydrogen peroxide combined catalytic oxidation technology, the residual refractory organic matters in the wastewater are further subjected to ring opening and chain breaking, and then the effluent of the rear ozone oxidation device 3 and the effluent of the front ozone oxidation device 2 are fed into the MBR reactor 4 together, so that the refractory organic matters in the wastewater are thoroughly removed.
(3) When the COD in the first wastewater is more than or equal to 300mg/L, the first wastewater is sequentially conveyed to the front ozone oxidation device 2, the rear ozone oxidation device 3 and the MBR reactor 4 for treatment.
Specifically, when COD in the first wastewater is more than or equal to 300mg/L, the first wastewater firstly enters the front ozone oxidation device 2, macromolecule, annular and other refractory organic matters in the wastewater are initially subjected to ring opening and chain breaking by utilizing ozone generated by the front ozone oxidation device 2, then enter the rear ozone oxidation device 3, the ozone oxidation effect is enhanced by utilizing the combined catalytic oxidation technology of ozone and hydrogen peroxide in the rear ozone oxidation device 3, the residual refractory organic matters in the wastewater are further subjected to ring opening and chain breaking, namely, the refractory organic matters are fully converted into micromolecular organic matters in a step-by-step enhancement mode through two-stage ozone series connection, and then enter the MBR reactor 4, and the COD in the wastewater is fully removed by utilizing the biological degradation of activated sludge and the double adsorption of activated carbon in the MBR reactor 4.
In the invention, in the operation mode (3), the effluent of the MBR reactor 4 can also flow back to the post-ozone oxidation device 3 for further treatment, wherein the reflux ratio can be adjusted according to the proportion of 0-50%.
In a preferred embodiment, the coagulation, flocculation and sedimentation treatment in step (1) is performed in a high-efficiency sedimentation device 1. Suspended matters, turbidity and the like in the biochemical wastewater can be removed through coagulation, flocculation and precipitation treatment, the insoluble COD of the wastewater is reduced, and the subsequent ozone addition amount can be reduced. In a specific embodiment, the high-efficiency precipitation device 1 is a high-efficiency precipitation tank.
In a specific embodiment, the high-efficiency sedimentation device 1 adopts a flocculation sedimentation integrated device with a forced sludge external circulation system, the device fully utilizes sedimentation net capturing and adsorption of a reflux sludge flocculation technology to remove suspended matters and COD, and can buffer impact of abrupt change of water quality of incoming water on a subsequent unit. The high-efficiency sedimentation device 1 comprises a coagulation area, a flocculation area and a clarification sedimentation area, and the structural form can be a steel structure or concrete. Biochemical processThe treated coal chemical wastewater firstly enters a coagulation area in a high-efficiency precipitation device 1, coagulant is added in the area, the reaction time is 3-5 min, a stirrer is arranged in the coagulation area, the rotating speed is 80-100 r/min, the wastewater after coagulation reaction enters a flocculation reaction area, flocculant is added in the area, meanwhile, return sludge is also injected into the tank to enhance flocculation effect, a guide cylinder, a flocculant adding ring and a flocculation stirrer are arranged in the flocculation reaction area, the wastewater after coagulation reaction and the return sludge are mixed in a pipeline and then enter the guide cylinder of the flocculation area, the quantity of the return sludge is regulated to be controlled within the range of 3-6% of the water inflow, and after the mixed liquid reacts with the added flocculant in the guide cylinder, the mixed liquid is slowly stirred and lifted to enter the flocculation area outside the guide cylinder by the flocculation stirrer, and larger and uniform alum flocs are formed. The flocculant is added through a flocculant adding ring arranged on the guide cylinder, the flocculation stirrer is provided with variable frequency, the rotating speed adjusting range is 10-40 r/min, and the reaction time of the flocculation area is controlled to be 15-25 min. The wastewater enters a clarification and precipitation area after flocculation treatment, and the surface load of the clarification area is 3-7 m 3 /(m 2 H), arranging a chute and a mud scraper in the clarification and precipitation area, wherein the chute module can realize the efficient separation of the mud and the clean water, and the chute is obliquely arranged at an angle of 60 degrees, and the oblique length is 1.0-1.5 m; the variable frequency setting of the mud scraper adopts the central transmission, the linear speed is 1.0-3.5 m/min, the mud at the bottom of the pool can be scraped into a mud bucket of a clarification sedimentation zone by the mud scraper, the mud concentration effect is promoted, and the concentration of the concentrated mud is about 50-200 g/L. The wastewater flows from bottom to top in the clarification and sedimentation zone, and the sedimented sludge slides downwards, so that the sedimented sludge slides downwards. In the process of water flow passing through the inclined pipe, particles sink, clarified water is collected by the upper water collecting tank of the clarified precipitation zone and is discharged, and the suspended matters in the water outlet can be reduced to below 15 mg/L. The sludge hopper of the clarification and sedimentation zone is provided with a sludge return pipe and a sludge external discharge pipe, and part of sludge is continuously circulated to the flocculation reaction tank through a sludge return pump by the sludge return pipe; the sludge in the sludge discharge pipe is discharged through a sludge discharge pump, and the surplus sludge is periodically pumped out.
In a preferred embodiment, in step (1), the coagulant used for coagulation is an aluminum salt and/or an iron salt. Wherein the aluminum salt is aluminum sulfate or polyaluminum chloride. Wherein the ferric salt is ferric chloride or polymeric ferric sulfate. Further preferably, the solid-to-liquid ratio of the coagulant to the wastewater to be treated is 30 to 80mg/L at the time of coagulation.
In a preferred embodiment, in step (1), the flocculant used in the flocculation is Polyacrylamide (PAM). Further preferably, the flocculation is performed such that the solid-to-liquid ratio of the flocculant to the wastewater to be treated is 0.5 to 2mg/L.
In the present invention, the MBR Reactor 4 refers to a Membrane bioreactor (Membrane Bio-Reactor). In a preferred embodiment, a membrane module is disposed in the MBR reactor 4, the pore size of the membrane used in the membrane module is 0.1-0.4 micrometers, the membrane module can be hollow fiber or plate type, and the produced water is pumped out by an MBR suction pump. Due to the adoption of the membrane component, the active sludge microorganisms in the pool can be kept in a higher concentration range, usually 8000-12000 mg/L, so that the biochemical reaction for degrading the sewage organic matters can be performed more efficiently and thoroughly; meanwhile, due to high filtering precision of the membrane, clear and transparent effluent is ensured, and high-quality produced water is obtained.
In a preferred embodiment, in the MBR reactor 4, the wastewater is mixed with activated carbon. That is, the activated carbon powder is added into the MBR membrane reactor, and the characteristics of the activated carbon, such as adsorption and degradation of organic matters, are utilized to enable the organic matters in the wastewater to be removed more thoroughly in cooperation with the MBR process.
It is further preferable that the solid-to-liquid ratio of the activated carbon to the wastewater is 0.5 to 1.0g/L, that is, the addition amount of the activated carbon is 0.5 to 1.0g/L.
In the invention, the effluent of the MBR reactor 4 is conveyed to an ultrafiltration device 5 for further treatment, and organic matters in the water can be further removed and SDI can be reduced through the ultrafiltration device 5. In a specific embodiment, MBR effluent is pumped by a water producing pump and then enters an MBR water producing tank, and then is lifted by the pump and enters an ultrafiltration device 5, so that macromolecular organic matters, colloid substances and the like in the wastewater are further removed by utilizing the filtration effect of an ultrafiltration membrane, and the stable operation of a reverse osmosis membrane device in the subsequent recycling process is ensured. In a preferred embodiment, the ultrafiltration device 5 adopts an external pressure type hollow fiber ultrafiltration membrane, so that the recovery rate of the wastewater is improved, the recovery rate of the ultrafiltration device 5 is 90%, and the rest 10% of wastewater of the ultrafiltration device 5 is returned to the high-efficiency sedimentation tank for reprocessing.
In the invention, the high-efficiency precipitation device 1 removes insoluble organic matters in the wastewater by removing most suspended matters and turbidity in the wastewater; when the front ozone oxidation device 2 and the rear ozone oxidation device 3 are decomposed in water by ozone, hydroxyl free radicals (OH) can be generated, and the strong oxidability of the hydroxyl free radicals is utilized, so that on one hand, the ring opening and chain breaking of macromolecules or cyclic organic matters in the wastewater can be realized, the biodegradability of the wastewater can be improved, and on the other hand, the dissolved COD in the wastewater can be partially degraded; removing soluble organic matters in the wastewater through deep biodegradation of activated sludge and adsorption of activated carbon in an MBR reactor, and further removing insoluble COD in the wastewater by utilizing the interception effect of a microfiltration membrane; the ultrafiltration device can intercept macromolecular substances such as suspended matters, colloid, particles and the like in the water through an ultrafiltration membrane, and can further reduce the insoluble COD of the effluent.
When the wastewater subjected to advanced treatment is required to be recycled, the effluent of the ultrafiltration device 5 is conveyed to a reverse osmosis device for treatment.
The invention also provides a system for advanced treatment of wastewater in coal chemical industry, which comprises a high-efficiency precipitation device 1, a front ozone oxidation device 2, a rear ozone oxidation device 3, an MBR reactor 4 and an ultrafiltration device 5 which are sequentially connected, wherein a water outlet of the MBR reactor 4 is connected with a water inlet of the rear ozone oxidation device 3, a water outlet of the front ozone oxidation device 2 is connected with a water inlet of the MBR reactor 4, a membrane component is arranged in the MBR reactor 4, and the membrane component is a microfiltration membrane;
delivering the biochemical-treated coal chemical wastewater into a high-efficiency precipitation device 1 to sequentially perform coagulation, flocculation and precipitation treatment;
the first wastewater from the high-efficiency precipitation device 1 is conveyed to the front ozone oxidation device 2 to carry out oxidation reaction with ozone, then is conveyed to the MBR reactor 4 to be treated, the obtained wastewater a is conveyed to the rear ozone oxidation device 3 to carry out oxidation reaction with ozone and hydrogen peroxide according to the reflux ratio of 0-60 percent, then is returned to the MBR reactor 4,
or, the first wastewater from the high-efficiency precipitation device 1 is conveyed to the front ozone oxidation device 2 to perform oxidation reaction with ozone, then conveyed to the rear ozone oxidation device 3 to perform oxidation reaction with ozone and hydrogen peroxide, and then conveyed to the MBR reactor 4 to be treated;
the wastewater from the MBR reactor 4 is sent to an ultrafiltration device 5 for treatment.
The present invention will be described in detail by way of examples, but the scope of the present invention is not limited thereto.
Example 1
In the embodiment, the COD concentration of the pretreated and biochemically treated coal chemical wastewater is 320mg/L, wherein the solubility COD is 265mg/L, and the suspended matter concentration is 50mg/L;
(1) The coal chemical wastewater after pretreatment and biochemical treatment is conveyed into a high-efficiency precipitation device 1 and is subjected to coagulation treatment, wherein coagulant is polyaluminium chloride, the addition amount is 40mg/L, the wastewater is subjected to flocculation treatment after reacting for 2min at the rotating speed of 80 revolutions per minute, wherein flocculant is anionic PAM, the addition amount is 1mg/L, the wastewater is subjected to precipitation treatment after reacting for 20min at the rotating speed of 30 revolutions per minute, and first wastewater is obtained, and the COD concentration in the first wastewater is 260mg/L, wherein the solubility COD is 248mg/L and the suspension concentration is 15mg/L;
(2) At this time, the COD of the first wastewater is more than 100mg/L and less than 300mg/L, so that the first wastewater is firstly conveyed into the front ozone oxidation device 2 to be subjected to oxidation reaction with ozone, wherein the ozone adding amount is 180mg/L, the contact time is 60min, the obtained wastewater is conveyed into the MBR reactor 4 to be treated, a membrane component is arranged in the MBR reactor 4, the aperture of a membrane used by the membrane component is 0.2 micrometers, activated carbon powder is added into the MBR reactor 4, the adding amount of the activated carbon is 0.6g/L, the wastewater a is obtained after 180min of treatment in the MBR reactor 4, part of the wastewater a is refluxed into the rear ozone oxidation device 3 to be subjected to oxidation reaction with ozone and hydrogen peroxide, the reflux ratio of the wastewater a is 50%, the ozone adding amount is 240mg/L, and the hydrogen peroxide adding amount is 120mg/L, and the obtained wastewater is returned into the MBR reactor 4 to be treated;
(3) The wastewater from the MBR reactor 4 is conveyed to an ultrafiltration device 5, and the ultrafiltration device 5 adopts an external pressure type hollow fiber ultrafiltration membrane, and the pore diameter of the membrane is 0.05 micrometer, so as to obtain the wastewater after the advanced treatment. Through detection, the COD concentration of the wastewater after the advanced treatment is 19mg/L, wherein the solubility COD is 18mg/L, and the turbidity is 0.1NTU.
Example 2
In the embodiment, the COD concentration of the pretreated and biochemically treated coal chemical wastewater is 500mg/L, wherein the solubility COD is 422mg/L, and the suspended matter concentration is 77mg/L;
(1) Conveying pretreated and biochemically treated coal chemical wastewater into a high-efficiency precipitation device 1, performing coagulation treatment, wherein a coagulant is ferric chloride, the addition amount is 60mg/L, reacting for 2.5min at a rotating speed of 88 revolutions per minute, performing flocculation treatment on the obtained wastewater, wherein a flocculant is anionic PAM, the addition amount is 1.2mg/L, reacting for 25min at a rotating speed of 23 revolutions per minute, and performing precipitation treatment on the obtained wastewater to obtain first wastewater, wherein the COD concentration in the first wastewater is 390mg/L, the solubility COD is 371mg/L and the suspended matter concentration is 18mg/L;
(2) At this time, COD of the first wastewater is more than 300mg/L, so that the first wastewater is firstly conveyed into the front ozone oxidation device 2 to perform oxidation reaction with ozone, wherein the ozone adding amount is 260mg/L, the contact time is 60min, then the first wastewater is conveyed into the rear ozone oxidation device 3 to perform oxidation reaction with ozone and hydrogen peroxide, wherein the ozone adding amount is 300mg/L, the hydrogen peroxide adding amount is 150mg/L, the contact time is 80min, then the first wastewater is conveyed into the MBR reactor 4 to be treated, a membrane component is arranged in the MBR reactor 4, the pore diameter of a membrane used by the membrane component is 0.2 micron, activated carbon powder is added into the MBR reactor 4, the adding amount of activated carbon is 0.9g/L, and the first wastewater is treated in the MBR reactor 4 for 180min;
(3) The wastewater from the MBR reactor 4 is conveyed to an ultrafiltration device 5, and the ultrafiltration device 5 adopts an external pressure type hollow fiber ultrafiltration membrane, and the pore diameter of the membrane is 0.05 micrometer, so as to obtain the wastewater after the advanced treatment. Through detection, the COD concentration of the wastewater after the advanced treatment is 27mg/L, wherein the solubility COD is 25mg/L, and the turbidity is 0.12NTU.
Example 3
In the embodiment, the COD concentration of the pretreated and biochemically treated coal chemical wastewater is 120mg/L, wherein the solubility COD is 89mg/L, and the suspended matter concentration is 40mg/L;
(1) The coal chemical wastewater after pretreatment and biochemical treatment is conveyed into a high-efficiency precipitation device 1 and is subjected to coagulation treatment, wherein coagulant is polyaluminium chloride, the addition amount is 30mg/L, the obtained wastewater is subjected to flocculation treatment after reacting for 2min at the rotating speed of 80 revolutions per minute, wherein flocculant is anionic PAM, the addition amount is 0.8mg/L, the obtained wastewater is subjected to precipitation treatment after reacting for 20min at the rotating speed of 25 revolutions per minute, so as to obtain first wastewater, and the COD concentration in the first wastewater is 92mg/L, wherein the solubility COD is 79mg/L and the suspended matter concentration is 15mg/L;
(2) At this time, the COD of the first wastewater is less than 100mg/L, so that the first wastewater is firstly conveyed into a front ozone oxidation device 2 to perform oxidation reaction with ozone, wherein the ozone addition amount is 60mg/L, the contact time is 60min, the obtained wastewater is conveyed into an MBR reactor 4 to be treated, a membrane component is arranged in the MBR reactor 4, the aperture of a membrane used by the membrane component is 0.2 micron, activated carbon powder is added into the MBR reactor 4, the addition amount of the activated carbon is 0.5g/L, the wastewater a is obtained after 180min of treatment in the MBR reactor 4, the reflux ratio of the wastewater a to the rear ozone oxidation device 3 is 0%, namely, the wastewater does not have reflux;
(3) The wastewater from the MBR reactor 4 is conveyed to an ultrafiltration device 5, and the ultrafiltration device 5 adopts an external pressure type hollow fiber ultrafiltration membrane, and the pore diameter of the membrane is 0.05 micrometer, so as to obtain the wastewater after the advanced treatment. Through detection, the COD concentration of the wastewater after the advanced treatment is 25mg/L, wherein the solubility COD is 24mg/L, and the turbidity is 0.1NTU.
Example 4
The procedure described in example 1 was followed, except that the reflux ratio of wastewater a was 0% (i.e., wastewater a was not refluxed). Through detection, the COD concentration of the wastewater after the advanced treatment is 58mg/L, wherein the solubility COD is 56mg/L, and the turbidity is 0.15NTU.
Specifically, in the comparative example, the pretreated and biochemically treated coal chemical wastewater is detected, the COD concentration is 320mg/L, the solubility COD is 265mg/L, and the suspended matter concentration is 50mg/L;
(1) The coal chemical wastewater after pretreatment and biochemical treatment is conveyed into a high-efficiency precipitation device 1 and is subjected to coagulation treatment, wherein coagulant is polyaluminium chloride, the addition amount is 40mg/L, the wastewater is subjected to flocculation treatment after reacting for 2min at the rotating speed of 80 revolutions per minute, wherein flocculant is anionic PAM, the addition amount is 1mg/L, the wastewater is subjected to precipitation treatment after reacting for 20min at the rotating speed of 30 revolutions per minute, and first wastewater is obtained, and the COD concentration in the first wastewater is 260mg/L, wherein the solubility COD is 248mg/L and the suspension concentration is 15mg/L;
(2) At this time, the COD of the first wastewater is less than 300mg/L, so that the first wastewater is firstly conveyed into a front ozone oxidation device 2 to perform oxidation reaction with ozone, wherein the ozone addition amount is 180mg/L, the contact time is 60min, the obtained wastewater is conveyed into an MBR reactor 4 to be treated, a membrane component is arranged in the MBR reactor 4, the aperture of a membrane used by the membrane component is 0.2 micron, activated carbon powder is added into the MBR reactor 4, the addition amount of the activated carbon is 0.6g/L, the wastewater a is obtained after 180min of treatment in the MBR reactor 4, the reflux ratio of the wastewater a to the rear ozone oxidation device 3 is 0%, namely, the wastewater does not have reflux;
(3) The wastewater from the MBR reactor 4 is conveyed to an ultrafiltration device 5, and the ultrafiltration device 5 adopts an external pressure type hollow fiber ultrafiltration membrane, and the pore diameter of the membrane is 0.05 micrometer, so as to obtain the wastewater after the advanced treatment.
Comparative example 1
The process according to example 2 was carried out, in contrast to this, in step (2) the wastewater was not treated by the post-ozonation apparatus 3 (i.e., the wastewater treated by the pre-ozonation apparatus was directly fed to the MBR reactor 4 for treatment).
The COD concentration of the wastewater after the advanced treatment is 105mg/L, wherein the solubility COD is 102mg/L and the turbidity is 0.2NTU.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. The method for deeply treating the coal chemical wastewater is characterized by comprising the following steps of:
(1) Sequentially carrying out coagulation, flocculation and precipitation treatment on the biochemical-treated coal chemical wastewater to obtain first wastewater;
(2) Sequentially conveying the first wastewater to a front ozone oxidation device and an MBR reactor for treatment, conveying the obtained wastewater a to a rear ozone oxidation device for treatment according to a reflux ratio of 0-60%, and then returning to the MBR reactor;
or sequentially conveying the first wastewater to a front ozone oxidation device, a rear ozone oxidation device and an MBR reactor for treatment;
(3) Delivering the wastewater from the MBR reactor to an ultrafiltration device for treatment;
wherein, in the MBR reactor, the used membrane is a microfiltration membrane;
in the front ozone oxidation device, the first wastewater and ozone are subjected to oxidation reaction;
in the post-ozone oxidation device, the wastewater is subjected to oxidation reaction with ozone and hydrogen peroxide.
2. The method according to claim 1, wherein step (2) specifically comprises:
when COD in the first wastewater is less than 100mg/L, sequentially conveying the first wastewater to a front ozone oxidation device and an MBR reactor for treatment;
when COD in the first wastewater is more than or equal to 100mg/L and less than 300mg/L, sequentially conveying the first wastewater to a front ozone oxidation device and an MBR reactor for treatment, conveying the obtained wastewater a to a rear ozone oxidation device for treatment according to a reflux ratio of not more than 60%, and then returning to the MBR reactor;
when the COD in the first wastewater is more than or equal to 300mg/L, the first wastewater is sequentially conveyed to a front ozone oxidation device, a rear ozone oxidation device and an MBR reactor for treatment.
3. The method according to claim 1, wherein in the step (1), the COD concentration in the biochemical-treated coal chemical wastewater is 100-500 mg/L and the suspended matter concentration is more than 40 mg/L.
4. The method according to claim 1, wherein in step (1), the coagulant used for coagulation is an aluminum salt or an iron salt.
5. The method according to claim 1 or 4, wherein in the step (1), the solid-to-liquid ratio of the coagulant to the wastewater to be treated is 30 to 80mg/L at the time of coagulation.
6. The method according to claim 5, wherein in step (1), the flocculant used in the flocculation is polyacrylamide.
7. The method according to claim 1 or 6, wherein in the flocculation in the step (1), the solid-to-liquid ratio of the flocculant to the wastewater to be treated is 0.5 to 2mg/L.
8. The method of claim 1, wherein in the MBR reactor, the wastewater to be treated is mixed with activated carbon.
9. The method of claim 8, wherein the solid to liquid ratio of activated carbon to wastewater to be treated in the MBR reactor is 0.5-1.0 g/L.
10. The system for advanced treatment of the coal chemical wastewater is characterized by comprising a high-efficiency precipitation device, a front ozone oxidation device, a rear ozone oxidation device, an MBR reactor and an ultrafiltration device which are sequentially connected, wherein a water outlet of the MBR reactor is connected with a water inlet of the rear ozone oxidation device, a water outlet of the front ozone oxidation device is connected with a water inlet of the MBR reactor, a membrane component is arranged in the MBR reactor, and the membrane component is a microfiltration membrane;
delivering the biochemical-treated coal chemical wastewater into the efficient precipitation device to sequentially perform coagulation, flocculation and precipitation treatment;
the first wastewater from the high-efficiency precipitation device is conveyed to the front ozone oxidation device to perform oxidation reaction with ozone, then conveyed to the MBR reactor to be treated, the obtained wastewater a is conveyed to the rear ozone oxidation device to perform oxidation reaction with ozone and hydrogen peroxide according to a reflux ratio of 0-60%, then returned to the MBR reactor,
or, conveying the first wastewater from the high-efficiency precipitation device to the front ozone oxidation device to perform oxidation reaction with ozone, then conveying the first wastewater to the rear ozone oxidation device to perform oxidation reaction with ozone and hydrogen peroxide, and then conveying the first wastewater to the MBR reactor to perform treatment;
and conveying the wastewater from the MBR reactor to the ultrafiltration device for treatment.
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