Method and equipment for treating wastewater containing organic pollutants

Abstract

The present application provides a method and device for treating wastewater containing organic pollutants. The method comprises: using magnetic Janus particles and magnetic field to separate water-insoluble organic matter from the wastewater; performing distillation to separate and recover partially dissolved organic matter in the wastewater; performing biochemical treatment to degrade partially dissolved organic matter in the wastewater using microorganisms; and performing ozone catalytic oxidation to oxidize dissolved and difficult-to-degrade organic matter in the wastewater. The device comprises: an oil-water separation unit, a distillation unit, a biochemical treatment unit, and an ozone catalytic oxidation unit.

Description

Technical Field

[0001] The present invention relates to the field of treatment of wastewater containing organic pollutants, and in particular to the field of treatment of wastewater containing high-concentration COD organic solvents. Specifically, the present invention provides a method and equipment suitable for treating wastewater containing organic pollutants. Background Art

[0002] Industrial consumption of petroleum and its derivatives has caused great pollution to the environment. The oil spill caused by marine oil spills, the oily wastewater produced by oil drilling, the sludge formed on the inner wall of the oil storage tank, the oil sand on the drilling platform, etc., have all caused great pressure on the relevant wastewater treatment. The wastewater of multiphase complex mixed system is difficult to treat for environmental protection. The traditional treatment method is mostly demulsification under compound surfactants, while small molecule surfactants are usually toxic and harmful, which will cause secondary pollution to the environment.

[0003] High-concentration COD organic solvent wastewater is one of the difficult-to-treat wastewaters. It has prominent problems such as difficulty in treatment, high energy consumption, and high pollution, and has become a major threat to the natural environment and human health. At present, the traditional method of treating high-concentration COD organic solvent wastewater mainly relies on incineration, and the gas it produces is easy to cause secondary pollution. At the same time, incineration consumes huge energy and is not a green environmental protection technology.

[0004] There are many types of organic pollutants with different properties contained in high-concentration COD organic solvent wastewater, such as water-insoluble organic matter (oily), water-soluble organic matter, etc. It is difficult to remove organic pollutants of different properties through a single wastewater treatment method or equipment, that is, it is difficult to make high-concentration COD organic solvent wastewater meet the discharge standards through a single wastewater treatment method or equipment.

[0005] Therefore, for wastewater containing organic pollutants, especially high-concentration COD organic solvent wastewater, there is an urgent need to provide a green and environmentally friendly solution that can efficiently remove various organic pollutants and achieve recycling and resource processing. Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The invention provides an integrated sewage treatment device and method capable of continuously separating or removing different organic pollutants.

[0008] The present invention firstly uses magnetic Janus particles and their supporting devices to treat wastewater containing organic matter, and uses the emulsification effect of magnetic Janus particles to remove the oil phase in the wastewater, wherein the oil phase includes floating oil, emulsified oil, solid oily matter, etc. This step can achieve complete removal of the oil phase, and provides sufficient conditions for subsequent distillation treatment, biochemical treatment and ozone catalytic oxidation treatment. The wastewater discharged after the above treatment can achieve fractionation and recovery of some soluble organic matter through the distillation device, and realize the regeneration of organic solvent resources. After the wastewater is treated in the above two stages, most of the organic matter is separated and recovered, but some dissolved organic matter still remains in the wastewater and is difficult to separate. The wastewater obtained by the above two-step treatment is introduced into the biochemical treatment device, and the degradation and removal of some organic matter can be achieved through biochemical treatment. Then, by introducing it into the ozone catalytic oxidation device, the oxidation technology is used to achieve the removal of the remaining difficult-to-degrade organic matter in the wastewater. The wastewater obtained after the above series of treatments has a significantly reduced COD value, and most of the organic solvents are separated and recovered.

[0009] Solutions for solving problems

[0010] The first aspect of the present invention is to provide a method for treating wastewater containing organic pollutants, which comprises: step 1: mixing magnetic Janus particles in wastewater containing organic pollutants to obtain an emulsion, and causing magnetic Janus particle droplets as a dispersed phase in the emulsion to migrate and / or enrich through the action of a magnetic field, thereby separating water-insoluble organic matter from the wastewater, and discharging treated liquid 1;

[0011] Step 2: distilling the treatment liquid 1, separating and recovering part of the dissolved organic matter, and discharging the treatment liquid 2;

[0012] Step 3: biochemically treat the treated liquid 2, using microorganisms to degrade some dissolved organic matter, and discharge the treated liquid 3;

[0013] Step 4: Perform ozone catalytic oxidation on the treatment liquid 3.

[0014] In some specific embodiments of the present invention, the step 1 comprises: forming a water dispersion with a solid content of 1 wt% to 20 wt% from magnetic Janus particles, mixing the water dispersion with the wastewater to obtain a stable water-in-oil emulsion, wherein magnetic Janus particle droplets formed by magnetic Janus particles coating water-insoluble organic matter serve as a dispersed phase; using a magnet to allow the magnetic Janus particle droplets to migrate and / or accumulate on or near the magnet; and discharging the continuous phase;

[0015] The amount of the magnetic Janus particles used relative to the wastewater containing organic pollutants is 0.01wt%-20wt%.

[0016] The magnetic Janus particles are NH2-Fe3O4-C8 particles.

[0017] The catalyst used in step 4 is selected from Co-Mn / ZrO2 catalyst.

[0018] The second aspect of the present invention is to provide a treatment device for wastewater containing organic pollutants, comprising:

[0019] Oil-water separation unit: it uses magnetic Janus particles and magnetic field to separate water-insoluble organic matter from the wastewater;

[0020] Distillation unit: used to separate part of the dissolved organic matter in the wastewater;

[0021] Biochemical treatment unit: used to degrade some organic matter in dissolved form;

[0022] Ozone catalytic oxidation unit: used for catalytic oxidation of dissolved and difficult-to-degrade organic matter.

[0023] In some specific embodiments of the present invention, in the oil-water separation unit, the magnetic Janus particle droplets are migrated and / or enriched by the action of a magnetic field to separate water-insoluble organic matter;

[0024] The magnetic Janus particle droplets are dispersed phases formed by magnetic Janus particles coating water-insoluble organic matter in an emulsion obtained by emulsifying the wastewater using magnetic Janus particles as a solid emulsifier.

[0025] In some specific embodiments of the present invention, the oil-water separation unit includes a magnetic control oil-water separation device, and the magnetic control oil-water separation device includes a container capable of containing wastewater; and

[0026] A magnet is configured to generate a magnetic force on the magnetic Janus particle emulsion droplets in the container.

[0027] Optionally, the magnet is configured to be fixed or configured to be movable or rotatable.

[0028] In some specific embodiments of the present invention, the distillation unit includes a rectification tower and a condenser.

[0029] The biochemical treatment unit comprises an anoxic tank, an aerobic tank and a sedimentation tank; the anoxic tank is provided with a water inlet, a lifting pump and a grid; the aerobic tank is provided with an inlet weir, an aeration device, a reflux device, an outlet weir and biological fillers;

[0030] The ozone catalytic oxidation unit comprises a control cabinet, a circulating water reservoir, a three-stage aeration tower and an ozone generator, wherein the three-stage aeration tower is loaded with a catalyst.

[0031] The third aspect of the present invention is to provide a method for treating wastewater containing organic pollutants using the above-mentioned treatment equipment, which comprises:

[0032] A step of separating water-insoluble organic matter from the wastewater by using magnetic Janus particles and a magnetic field;

[0033] The step of distilling the treated liquid obtained in the previous step to separate and recover part of the dissolved organic matter in the wastewater;

[0034] The treatment liquid obtained in the previous step is subjected to biochemical treatment to degrade part of the dissolved organic matter in the wastewater by using microorganisms;

[0035] The treated liquid obtained in the previous step is subjected to ozone catalytic oxidation to oxidize dissolved and difficult-to-degrade organic matter in the wastewater.

[0036] Effects of the Invention

[0037] The method and equipment for treating wastewater containing organic pollutants provided by the present invention can realize the continuous and gradual separation or removal of different organic pollutants contained in the wastewater, and can realize the recovery of some organic solvents. It is an integrated sewage treatment method and equipment. It can efficiently treat wastewater containing high-concentration organic solvents to meet the discharge standards and is green and environmentally friendly.

[0038] The present invention utilizes magnetic Janus particles in combination with corresponding supporting equipment to achieve oil-water separation of high-concentration COD organic solvent wastewater, separates water-insoluble organic solvents (for example, floating oil, emulsified oil and solid oil), and the wastewater discharged after treatment enters a distillation tower for distillation, through which most of the dissolved organic solvents can be recovered. Among them, the magnetic Janus particles are environmentally friendly and can be reused.

[0039] Then, the remaining wastewater enters the biochemical water treatment device to degrade some of the dissolved organic solvents, and the discharged wastewater enters the ozone catalytic oxidation device to degrade most of the remaining dissolved organic matter. After treatment through the above technical route, the COD value of high-concentration COD organic solvent wastewater can be greatly reduced, part of the separated solvent can be recycled and reused, and the residual wastewater can be discharged in compliance with the standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 : Schematic diagram of the technical route of the present invention.

[0041] Figure 2 : (a) is a schematic diagram of a magnetically controlled oil-water separation device in a specific scheme; (b) is an enlarged view of part A in (a); (c) is a front view of the magnetically controlled oil-water separation device.

[0042] Figure 3 : Schematic diagram of an exemplary distillation unit process flow.

[0043] Figure 4 : Schematic diagram of an exemplary biochemical processing unit.

[0044] Figure 5 : Schematic diagram of an exemplary ozone catalytic oxidation unit.

[0045] Description of Reference Numerals

[0046] Figure 2 middle:

[0047] 1. Separator; 101. Water tank; 102. Driving motor; 103. Magnetic turntable; 104. Mounting slot; 105. Fixed shaft; 106. Scraper; 107. Fixed plate; 108. Tension spring; 109. Collecting cylinder; 2. Mixer; 21. Mixing box; 22. Water inlet pipe; 3. Magnetic Janus particle disperser; 4. Recycler; 41. Recycling box; 42. Sludge discharge pipe; 5. Sewage inlet pipe; 6. Vertical pipe; 7. First conduit; 8. Second conduit; 9. Dirt cover; 10. Moving magnet; 11. Fixed magnet; 12. Transparent glass plate; 13. Sewage discharge pipe; 14. Pipe cover.

[0048] Figure 3 middle:

[0049] 1-1: water inlet; 1-2: grid; 1-3: lifting pump; 2-1: water inlet weir; 2-2: aeration device; 2-3: return weir; 2-4: water outlet weir; 2-5: biological filler; 3-1: water outlet DETAILED DESCRIPTION

[0050] In this specification, the use of "may" or "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0051] In this specification, the unit names used are all international standard unit names, and unless otherwise stated, the "%" used represents weight or mass percentage.

[0052] "Wastewater containing organic pollutants" or "wastewater containing organic matter" in this specification refers to wastewater containing organic pollutants, sometimes also referred to as "wastewater containing organic solvents", which mainly comes from sewage containing organic solvent components, a part of the organic solvent exists in the form of oil phase, and the other part exists in dissolved form. Among them, organic pollutants existing in the form of oil phase can also be called "water-insoluble organic matter", that is, including organic matter that is immiscible with water, for example, floating oil, emulsified oil, and solid oily matter. Organic matter existing in dissolved form can also be called "dissolved form organic matter", which includes organic matter with a certain solubility in water, for example, including methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol, glycerol, acetone, tetrahydrofuran, N,N-isopropylacrylamide, ether, dimethyl ether, acetic acid, etc., and also includes organic matter with low solubility in water or insoluble in water but miscible with the above-mentioned organic matter with a certain solubility in water, for example, toluene, xylene, etc.

[0053] In this specification, "magnetic Janus particles" refer to amphiphilic particles that can respond to a magnetic field. There is no particular limitation on the type of particles, as long as they are magnetic and amphiphilic and can act as a solid emulsifier. For example, amphiphilic magnetic organic / inorganic composite particles, etc. The average particle size of the magnetic Janus particles can be 10-2000nm.

[0054] In this specification, "magnetic Janus particle emulsion" refers to an emulsion obtained by dispersing magnetic Janus particles as a solid emulsifier in a target treatment liquid and emulsifying the emulsion, in which the magnetic Janus particles cover oil droplets to form a dispersed phase and are dispersed in an aqueous phase as a continuous phase.

[0055] The target treatment liquid includes wastewater containing organic pollutants, especially wastewater containing high-concentration organic solvent pollutants, for example, high-concentration COD organic solvent wastewater, whose COD value is about 250,000-300,000 ppm.

[0056] The "COD" mentioned above refers to chemical oxygen demand, which is an important indicator for characterizing organic pollution in water bodies. It is a chemical method for measuring the amount of reducing substances in a water sample that need to be oxidized. The reducing substances in wastewater mainly include organic matter. The larger the COD value, the more serious the water body is polluted by organic matter.

[0057] The sources of the high-concentration COD organic solvent wastewater include pharmaceutical wastewater, chemical fertilizer wastewater, textile printing and dyeing wastewater, dye wastewater, leather wastewater, pesticide wastewater, etc. The amount of magnetic Janus particles relative to the target treatment liquid can be determined and adjusted according to the pollution degree and oil content of the target treatment liquid, for example, it can be 0.01-20wt%.

[0058] The present invention provides a method for treating wastewater containing organic pollutants, which comprises:

[0059] Step 1: Mixing magnetic Janus particles in wastewater containing organic pollutants to obtain an emulsion, and causing magnetic Janus particle droplets as a dispersed phase in the emulsion to migrate and / or enrich through the action of a magnetic field, thereby separating water-insoluble organic matter from the wastewater, and discharging a treated liquid 1;

[0060] Step 2: distilling the treatment liquid 1, separating and recovering part of the dissolved organic matter, and discharging the treatment liquid 2;

[0061] Step 3: biochemically treat the treated liquid 2, using microorganisms to degrade some dissolved organic matter, and discharge the treated liquid 3;

[0062] Step 4: Perform ozone catalytic oxidation on the treatment liquid 3.

[0063] In a specific embodiment, the step 1 comprises: forming the magnetic Janus particles into an aqueous dispersion having a solid content of 1 wt% to 20 wt%, mixing the aqueous dispersion with the wastewater to obtain a stable water-in-oil emulsion, wherein magnetic Janus particle droplets formed by magnetic Janus particles coating water-insoluble organic matter serve as a dispersed phase; using a magnet to cause the magnetic Janus particle droplets to migrate and / or accumulate on or near the magnet; and discharging the continuous phase.

[0064] A portion of the dissolved organic solvent in the continuous phase can be separated by distillation, and the other portion of dissolved organic pollutants that are difficult to separate by distillation can be further removed through microbial degradation and catalytic oxidation degradation.

[0065] The above steps 1-4 can be implemented in the oil-water separation unit, the distillation unit, the biochemical treatment unit, and the ozone catalytic oxidation unit, respectively.

[0066] Oil-water separation unit:

[0067] In the oil-water separation unit, water-insoluble organic matter is separated from the wastewater by using magnetic Janus particles and magnetic field. Specifically, magnetic Janus particles are formed into an aqueous dispersion with a solid content of 1wt%-20wt%, the aqueous dispersion is mixed with the wastewater, and a stable water-in-oil emulsion is obtained through appropriate shearing, wherein magnetic Janus particle droplets formed by magnetic Janus particles coating water-insoluble organic matter serve as a dispersed phase; the magnetic field generated by a magnet causes the magnetic Janus particle droplets to migrate and / or accumulate on or near the magnet, thereby separating the water-insoluble organic matter; and a continuous phase is discharged, wherein the continuous phase contains dissolved organic matter. The continuous phase enters the distillation unit as the treated liquid 1 for subsequent distillation treatment.

[0068] The oil-water separation unit comprises a magnetically controlled oil-water separation device capable of implementing the above-mentioned solution, wherein the device comprises a container capable of containing wastewater and a magnet configured to generate a magnetic force on the magnetic Janus particle droplets in the container.

[0069] The magnetic Janus particles used in the present invention are not particularly limited. Any existing Janus particles having magnetic properties and amphiphilicity and capable of being used as a solid emulsifier may be used, preferably NH2-Fe3O4-C8.

[0070] The Fe3O4 in the NH2-Fe3O4-C8 particles is magnetic, and the Fe3O4 surface has a silicon oxide shell. Part of the particle surface has amino groups (-NH2), that is, the hydrophilic part, and part has C8 groups, that is, the hydrophobic part obtained by modification with n-octyltriethoxysilane.

[0071] NH2-Fe3O4-C8 can be prepared by the following method. 1g of Fe3O4 nanoparticles with a particle size range of 100-200nm is used as carrier particles; 0.01-0.2g of ethyl orthosilicate is used to prepare a silicon oxide shell with a thickness of 5-50nm on the surface of the Fe3O4 nanoparticles through a sol-gel process to obtain composite magnetic nanoparticles; the composite magnetic nanoparticles are used as particle emulsifiers, and a stable water-in-oil emulsion is obtained by emulsifying 50g of water and 10g of paraffin at a temperature of 60°C, and solid paraffin droplets with stable particles are obtained after cooling to room temperature, and the particles are embedded in the oil-water interface, one side is exposed to the water phase, and the other side is embedded in the paraffin phase; the solid paraffin droplets obtained above are dispersed in 10g of dimethyl sulfoxide DMSO solvent, and first modified with aminopropyltriethoxysilane (the addition amount is 1%-10% of the mass of the Fe3O4 nanoparticles), and the surface grafting modification of the silane coupling agent can be achieved within 1 hour through a simple stirring process. Furthermore, the solid paraffin droplets are separated by centrifugation, dissolved in 10 g of ethanol solvent, and centrifuged again to obtain magnetic particles with amino modification on one side. The amino-modified magnetic particles are dispersed again in 10 g of ethanol, and then modified with n-octyltriethoxysilane (the addition amount is 1%-10% of the mass of the Fe3O4 nanoparticles), and the hydrophobic part of the other side can be modified again. Finally, magnetic Janus particles are obtained.

[0072] The magnet used in the present invention is not particularly limited, and any conventional magnet in the art can be used, for example, a samarium cobalt magnet, a neodymium iron boron magnet, a ferrite magnet, an aluminum nickel cobalt magnet, an iron chromium cobalt magnet, etc. The configuration of the magnet generates a magnetic field in the container or the processing chamber, and the magnetic induction intensity is in the range of 500-25000 Gauss (Gs). There is no particular limitation on the shape of the magnet, as long as it can be adapted to the processing chamber, for example, it can be plate-shaped, block-shaped, columnar, etc.

[0073] In a specific embodiment of the present invention, a magnetic oil-water separation device includes: a water tank, a water inlet, a water outlet, an oil outlet, a scraper, a supporting rotating rod, a magnet, a motor, a driven wheel, a transmission belt, etc. The power of the magnetic oil-water separation device is 0.5-1.0kw, the operating temperature is not particularly limited, and the range is 1-100℃, and the flow rate can be 0.5m 3 -2.5m 3 / h.

[0074] In a specific scheme, the specific operation process and procedure in the oil-water separation unit are as follows: an aqueous dispersion of magnetic Janus particles (solid content 1%-20wt%) is mixed with wastewater containing organic pollutants to be treated, and a stable water-in-oil emulsion is obtained through shearing; the above-mentioned water-in-oil emulsion flows into a water tank through a water inlet, and the magnet is partially immersed in the water flow and the emulsion stabilized by the magnetic particles is pulled and adsorbed through magnetic manipulation; the motor rotates to drive the transmission belt, thereby driving the driven wheel to rotate, and then driving the supporting rotating rod, which is connected to the magnet, so that the magnet rotates; the rotation of the magnet drives the magnetic Janus particle droplets adsorbed on its surface to leave the water flow; through the action of the scraper, the magnetic particles on the magnet and its stable oil phase droplets are separated from the magnet; the solvent wastewater after the oil phase is separated is discharged through the outlet to achieve oil-water separation.

[0075] In one specific embodiment, the oil-water separation unit adopts Figure 2 The oil-water separation device shown in the figure is equipped with a separator, a mixer, a magnetic Janus particle disperser and a recoverer.

[0076] Magnetic Janus particles are added to the magnetic Janus particle disperser 3 for dispersion, and then the magnetic Janus particle dispersion is introduced into the mixer 2 through the vertical pipe 6 to mix with the sewage to form an emulsion. After the magnetic Janus particles are mixed with the oily sewage, they are enriched at the oil-water interface and the oil phase is wrapped to form magnetic Janus particle droplets. The emulsion enters the separator 1 through the sewage inlet pipe 5 for separation, and the driving motor 102 is controlled to run. The output shaft of the driving motor 102 drives the magnetic turntable 103 to rotate, and the magnetic Janus particle droplets are adsorbed on the magnetic turntable 103, so that the oil pollution and the sewage can be separated. Under the action of the tension spring 108, the scraper 106 can fit tightly on the outer edge of the magnetic turntable 103, so that the magnetic Janus particle droplets on the magnetic turntable 103 can be scraped off, and the magnetic Janus particles and the coated oil phase enter the collecting cylinder 109 along the scraper 106, and enter the recovery device 4 through the first conduit 7. The recovery device 4 separates the oil pollution and the magnetic Janus particles, and transports the recovered magnetic Janus particles to the mixer 2 for reuse.

[0077] Distillation unit:

[0078] The distillation unit is used to separate part of the dissolved organic matter contained in the wastewater, and conventional distillation devices in the art can be used as long as the above-mentioned purpose can be achieved.

[0079] In a specific scheme, the processing capacity of the distillation treatment device used is 60t / d, and the wastewater it treats contains some dissolved solvents that cannot be effectively separated by the oil-water separation unit (this component is a low-boiling point component, with a boiling point lower than that of the main target product and produces an azeotropic effect with water. Its composition is uncertain and depends on the type or source of the wastewater).

[0080] Through the distillation unit, useful components in wastewater (for example, organic solvents such as methanol, ethanol and mixed products of usable components) can be purified and separated. The main processes include distillation and condensation, which will produce a part of mixed solvents with utilization value.

[0081] In a specific scheme, the production process is as follows: for wastewater that has been treated with oil-water separation, its COD data is confirmed. The wastewater to be treated is collected and placed in an intermediate storage tank for standby use. During production, the wastewater to be treated is pumped into a distillation tower using a diaphragm pump. Next, the wastewater in the distillation tower is heated and distilled step by step according to the boiling points of each target product.

[0082] Preferably, four distillations are performed according to the boiling point of the target product, the first distillation temperature is set to 75°C to fractionate out, for example, methanol, ethanol, etc., the second distillation temperature is set to 90°C to fractionate out, for example, toluene, xylene, etc., the third distillation temperature is set to 100°C to mainly fractionate out water, and the fourth distillation temperature is set to, for example, 200°C to fractionate out the medium boiling point components.

[0083] In a specific scheme, first, the distillation tower is heated by jacket steam for the first distillation, the temperature is set to 75°C, the low-boiling substances are evaporated from the wastewater to be treated, condensed in the condenser, and indirectly condensed in the condenser through cooling water (the condensation method is indirect condensation, water is used as a refrigerant, and the cooling medium is tap water), and the products (for example, mainly methanol, ethanol, etc.) are fractionated. After the above operation is completed, the remaining wastewater to be treated in the distillation tower is heated and distilled for the second time, the temperature is set to 90°C, the substances that azeotropy with water are evaporated from the wastewater to be treated, condensed in the condenser, and the products (for example, mainly toluene, xylene, etc.) are fractionated. After the above operation is completed, the remaining wastewater in the distillation tower is heated and distilled for the third time, the temperature is set to 100°C, water is evaporated from the wastewater, condensed in the condenser, and the products (mainly water) are fractionated. Finally, the remaining kettle liquid in the distillation tower is heated and distilled for the fourth time, and the temperature is raised to 200°C. At this time, the medium-boiling point components in the residual liquid evaporate and can be sold as by-products after condensation in the condenser. The distillation residue is discharged and subsequently used as the treatment liquid 2 for the next step of biochemical treatment.

[0084] The device may include a set of distillation towers and two sets of corresponding condensation devices. In the condenser, the exhaust gas is indirectly condensed by cooling water to achieve a good condensation effect. During the condensation process, the exhaust gas passes through multiple tower sections to reach the top of the tower. The height of the distillation tower (including the distillation facilities and the condensation device) is 15m, and the condenser area is 80m 2 The mass and heat transfer in the condensation process is sufficient, and the condensation efficiency is high. By accurately adjusting the temperature in the tower, the effective separation of possible azeotropes is ensured. When necessary, a small amount of extractant will be added to ensure the separation efficiency. The extractant is pumped into the inlet pipeline set in the distillation kettle. According to actual conditions, the extractant can be recycled multiple times after condensation.

[0085] Biochemical treatment unit:

[0086] After the wastewater is treated by the above two units, most of the organic matter is separated and recovered, but some water-soluble organic matter still remains in the wastewater and is difficult to separate. The biochemical treatment unit is used to biochemically treat the treatment liquid obtained in the previous step and use microorganisms to degrade some of the dissolved organic matter in the wastewater.

[0087] The biochemical treatment unit may adopt conventional devices in the art as long as the above-mentioned purpose can be achieved.

[0088] In a specific scheme, the sewage biochemical treatment unit includes three parts: anoxic tank, aerobic tank and sedimentation tank. The anoxic tank is equipped with an inlet, a lifting pump and a grid; the aerobic tank is equipped with an inlet weir, an aeration device, a reflux device, an outlet weir and biological filler; the sedimentation tank has an outlet on the outer wall. 3 / d, the temperature range of the anoxic tank is 5-25°C, and the pH value is 6.5-7.5; the temperature range of the aerobic tank is 10-35°C, and the pH value is 7.5-8.5. The device power is 5-10kW. In the present invention, conventional strains can be used in the anoxic tank and the aerobic tank. In a specific embodiment, denitrifying bacteria, such as Pseudomonas, are used in the anoxic tank; nitrite bacteria, such as Micrococcus, nitrate bacteria, such as Proteus, and polyphosphate bacteria, such as Proteus, are used in the aerobic tank, and the dosage is, for example, 10 mg / L.

[0089] In this process unit, BOD5 can be used as an evaluation index. BOD5 is the five-day biochemical oxygen demand, which is an indicator that indirectly indicates the degree of organic pollution in water bodies by using the amount of dissolved oxygen consumed by microbial metabolism. It can reflect the degree of organic pollution in wastewater. The more organic matter contained in the wastewater, the more oxygen is consumed, and the higher the BOD5 value is, and vice versa.

[0090] In a specific scheme, the wastewater biochemical treatment process and process are as follows: the wastewater to be treated enters from the water inlet, filters the large suspended particles through the grid, and then enters the anoxic tank. The anoxic tank is an oxygen-deficient and weakly alkaline environment. Denitrifying bacteria use organic matter in the sewage as a carbon source to reduce the large amount of NO3-N and NO2-N brought into the aerobic tank return liquid to N through denitrification. 2 Released into the air, the BOD5 concentration decreases, and the NO3-N concentration decreases significantly. The sewage in the anoxic tank is evenly distributed to the aerobic tank through the water inlet weir by the lifting pump. The sewage undergoes aerobic biodegradation in the aerobic tank. Under aerobic conditions, the organic matter is biochemically degraded by microorganisms, and the BOD5 concentration continues to decrease; through the action of nitrite bacteria and nitrate bacteria, NH3-N is oxidized into NO3-N and NO2-N, which significantly reduces the NH3-N concentration, but with the nitrification process, the concentrations of NO3-N and NO2-N increase; phosphorus also decreases at a faster rate under the action of polyphosphate bacteria. Microorganisms that can accumulate phosphorus in the activated sludge of the aerobic tank can absorb a large amount of soluble phosphorus, convert it into insoluble polyorthophosphates and store it in the body, and finally discharge the remaining sludge through the sedimentation tank to achieve the purpose of system phosphorus removal. This process has the functions of organic matter removal, nitrification denitrification and phosphorus removal.

[0091] Wastewater treated by the biochemical treatment unit, that is, the effluent after microbial degradation of some dissolved organic matter, may still contain dissolved organic matter that is difficult to be degraded by microorganisms. It is introduced as the treated liquid 3 into the subsequent ozone catalytic oxidation unit for subsequent treatment.

[0092] Ozone catalytic oxidation unit:

[0093] The treated liquid obtained from the previous unit treatment may contain organic matter in dissolved form that is difficult to be degraded by microorganisms. Ozone catalytic oxidation is performed on this wastewater to remove such substances.

[0094] In a specific embodiment of the present invention, the ozone catalytic oxidation unit mainly includes a control cabinet, a circulating water reservoir, a three-stage aeration tower, an ozone generator, etc. The three-stage aeration tower is loaded with a catalyst.

[0095] After the above-mentioned operation process, the COD value of high-concentration COD organic solvent oily wastewater is greatly reduced, but some difficult-to-degrade organic pollutants still remain. The wastewater discharged after the above three units is introduced into the ozone catalytic oxidation device, with a flow rate of 0.5-2.0 tons / hour, cyclic treatment, and a single ton-level treatment time of 2-4 hours. The control cabinet controls the process parameters, injects the wastewater into the circulating water tank, and pumps it into the three-stage aeration tower. The aeration tower has a capacity of 0.5 tons and is loaded with Co-Mn / ZrO2 catalyst.

[0096] Ozone is generated by an ozone generator with an ozone generation rate of 200g / h. Ozone is introduced into the device to achieve a catalytic oxidation process. The COD of the wastewater treated by the above process is greatly reduced.

[0097] The treatment equipment for wastewater containing organic pollutants of the present invention includes an oil-water separation unit connected in sequence; a distillation unit for separating partially dissolved organic matter in the wastewater; a biochemical treatment unit for degrading partially dissolved organic matter; and an ozone catalytic oxidation unit for catalytically oxidizing dissolved and difficult-to-degrade organic matter, thereby enabling continuous and step-by-step separation or removal of different organic pollutants contained in the wastewater. For high-concentration COD organic solvent wastewater, the COD value can be reduced from about 250,000-300,000 ppm to about 200 ppm by treatment with the above-mentioned treatment equipment. The technical solution claimed to be protected by the present invention is described below through specific embodiments.

[0098] The COD value test method of wastewater is as follows:

[0099] Take 10.00 mL of water sample, add pure water to 20.00 mL, and use different concentrations of potassium dichromate (0.25, 0.025 mol / L) for oxidation. The remaining steps are tested according to the operating method in HJ-T-70-2001.

[0100] The COD value of the oil-containing high-concentration COD organic solvent wastewater used in Example 1 is 250,000 ppm, and its source is pharmaceutical wastewater.

[0101] The COD value of the oil-containing high-concentration COD organic solvent wastewater used in Example 2 is 200,000 ppm, and its source is pharmaceutical wastewater.

[0102] Preparation example: Preparation of NH2-Fe3O4-C8 particles

[0103] 1g of Fe3O4 nanoparticles with a particle size range of 100-200nm is used as carrier particles; 0.01-0.2g of tetraethyl orthosilicate is used to prepare a silicon oxide shell with a thickness of 5-50nm on the surface of the Fe3O4 nanoparticles through a sol-gel process to obtain composite magnetic nanoparticles; the composite magnetic nanoparticles are used as particle emulsifiers to emulsify 50g of water and 10g of paraffin at a temperature of 60°C to obtain a stable water-in-oil emulsion, and after cooling to room temperature, solid paraffin droplets with stable particles are obtained, and the particles are embedded in the oil-water interface, one side is exposed to the water phase, and the other side is embedded in the paraffin phase; the solid paraffin droplets obtained above are dispersed in 10g of dimethyl sulfoxide (DMSO) solvent, and first modified with aminopropyltriethoxysilane (the addition amount is 1%-10% of the mass of the Fe3O4 nanoparticles), and the surface grafting modification of the silane coupling agent can be achieved within 1 hour through a simple stirring process. Furthermore, the solid paraffin droplets are separated by centrifugation, dissolved in 10 g of ethanol solvent, and centrifuged again to obtain magnetic particles with amino modification on one side. The amino modified magnetic particles are dispersed again in 10 g of ethanol, and then modified with n-octyltriethoxysilane (the addition amount is 1%-10% of the mass of Fe3O4 nanoparticles), and the hydrophobic part of the other side can be modified again. Finally, magnetic Janus particles NH2-Fe3O4-C8 are obtained.

[0104] Embodiment 1:

[0105] For a kind of oil-containing high-concentration COD organic solvent wastewater, 1kg of magnetic Janus particles are dispersed in a water system through an ultrasonic dispersion system to obtain a dispersion. The magnetic Janus particle dispersion is mixed with high-concentration COD oil-containing organic solvent wastewater with a COD value of 250,000, and the amount of magnetic Janus particles relative to the wastewater is 1wt%. Under the action of strong mechanical stirring, stable emulsification is achieved, and the oil phase solvent is emulsified to obtain dispersed phase oil droplets. The oil droplets stabilized by the magnetic Janus particles are separated under the treatment of a magnetic separation device, thereby achieving the separation of the oil phase solvent and the water phase in the system.

[0106] The organic solvent wastewater after the oil phase solvent separation still contains some dissolved organic solvents, but its COD value drops significantly to 150,000. The above-mentioned discharged wastewater is further pumped into a distillation device, and a large amount of dissolved solvents can be separated and recovered through the distillation process. First, the distillation tower is heated by jacket steam for the first distillation, and the temperature is set to 75°C. The low-boiling substances are evaporated from the high-concentration wastewater, and the cooling water is indirectly condensed in the condenser (the condensation method is indirect condensation, using water as a refrigerant, and the cooling medium is tap water). The products (mainly methanol, ethanol, etc.) are distilled out, and the COD can be reduced from 150,000 to about 100,000. After the above operation is completed, the remaining waste liquid in the distillation tower is heated and distilled for the second time, and the temperature is set to 90°C. The substances that are azeotropic with water are evaporated from the waste liquid, condensed in the condenser, and the products (mainly toluene, xylene, etc.) are distilled out, which can reduce the COD of the waste liquid from 100,000 to about 30,000. After the above operation is completed, the remaining waste liquid in the distillation tower is heated and distilled for the third time, the temperature is set at 100°C, water is evaporated from the waste liquid, condensed in the condenser, and the product (mainly water) is fractionated. Finally, the remaining kettle liquid in the distillation tower is heated and distilled for the fourth time, the temperature is raised to 200°C, at this time, the medium boiling point components in the residual liquid are evaporated, condensed in the condenser, and sold as a by-product. The COD of the tower bottom residual liquid is basically around 20,000.

[0107] Then the above-mentioned effluent is continuously pumped into the next working unit. The biochemical treatment device first passes through the anoxic tank, whose temperature range is 5-25°C and pH value is 6.5-7.5; then passes through the aerobic tank, whose temperature range is 10-35°C and pH value is 7.5-8.5, and finally enters the sedimentation tank. The bacterial species are Proteus, Pseudomonas and Micrococcus. Among them, Pseudomonas is located in the anoxic tank, and Proteus and Micrococcus are located in the aerobic tank. The waste liquid COD is further reduced to 5000 by the biochemical treatment device. The above-mentioned effluent has undergone a series of oil-water separation, recovery of dissolved organic solvents and biochemical treatment. Most of the COD can be removed by separation, recovery and biochemical degradation, but a small amount of dissolved organic solvents that are difficult to degrade still remain. The above-mentioned effluent is further pumped into the ozone catalytic oxidation device to achieve partial removal of the remaining dissolved organic matter. The ozone catalytic oxidation device has a treatment flow of 1t / h, a circulating treatment capacity of 1t / h, an ozone consumption mass of 250g, and uses a Co-Mn / ZrO2 catalyst. Through the above-mentioned series of treatment processes, its COD value is reduced to about 200, meeting the emission standards.

[0108] Embodiment 2:

[0109] For a kind of oil-containing high-concentration COD organic solvent wastewater, 1kg of magnetic Janus particles are dispersed in a water system through an ultrasonic dispersion system to obtain a dispersion. The magnetic Janus particle dispersion is mixed with high-concentration COD oil-containing organic solvent wastewater with a COD value of 200,000, and the amount of magnetic Janus particles relative to the wastewater is 1wt%. Under the action of strong mechanical stirring, stable emulsification is achieved, and the oil phase solvent is emulsified to obtain dispersed phase oil droplets stable with magnetic Janus particles. The oil droplets stable with magnetic Janus particles are enriched on the magnet under the treatment of magnetic separation equipment, thereby realizing the separation of the oil phase solvent and the water phase in the system. The organic solvent wastewater after the oil phase solvent is separated still contains some soluble organic solvents, but its COD value is greatly reduced to 100,000.

[0110] The above-mentioned discharged wastewater is further pumped into a distillation device, and a large amount of soluble solvents are separated and recovered through the distillation process, and the COD value of the effluent from this section is reduced to 30,000. Then the above-mentioned effluent is continuously pumped into the next working unit, and the COD is further reduced to 3,000 through a biochemical treatment device. The above-mentioned effluent has undergone a series of oil-water separation, recovery of dissolved organic solvents and biochemical treatment, and most of the COD is removed by separation, recovery and biochemical degradation, but a small amount of soluble and difficult-to-degrade COD remains. The above-mentioned effluent is further pumped into an ozone catalytic oxidation device to partially remove the remaining dissolved COD. The treatment flow rate of the ozone catalytic oxidation device is 1t / h, the circulation treatment capacity is 1t / h, the ozone consumption mass is 200g, and a Co-Mn / ZrO2 catalyst is used. Through the above-mentioned complete series of treatment processes, its COD value is reduced to about 200, meeting the emission standards.

Claims

1. A method for treating wastewater containing organic pollutants, characterized in that: include: Step 1: Mixing magnetic Janus particles in wastewater containing organic pollutants to obtain an emulsion, and causing magnetic Janus particle droplets as a dispersed phase in the emulsion to migrate and / or enrich through the action of a magnetic field, thereby separating water-insoluble organic matter from the wastewater, and discharging a treated liquid 1, wherein the magnetic Janus particles are NH2-Fe3O4-C8 particles, and a portion of the surface of the NH2-Fe3O4-C8 particles has an amino group, i.e., a hydrophilic portion, and a portion has a C8 group, i.e., a hydrophobic portion obtained by modification with n-octyltriethoxysilane; Step 2: distilling the treatment liquid 1, separating and recovering part of the dissolved organic matter, and discharging the treatment liquid 2; Step 3: biochemically treat the treated liquid 2, using microorganisms to degrade some dissolved organic matter, and discharge the treated liquid 3; Step 4: performing ozone catalytic oxidation on the treatment liquid 3; Furthermore, the step 1 comprises: forming a water dispersion with a solid content of 1wt% to 20wt% from the magnetic Janus particles, mixing the water dispersion with the wastewater to obtain a stable water-in-oil emulsion, wherein magnetic Janus particle droplets formed by magnetic Janus particles coating water-insoluble organic matter serve as a dispersed phase; using a magnet to make the magnetic Janus particle droplets migrate and / or accumulate on or near the magnet; and discharging the continuous phase; The amount of the magnetic Janus particles used relative to the wastewater containing organic pollutants is 0.01wt%-20wt%.

2. The processing method according to claim 1, characterized in that: The catalyst used in step 4 is selected from Co-Mn / ZrO2 catalyst.

3. A treatment device for wastewater containing organic pollutants, characterized in that: It includes the following units connected in sequence: Oil-water separation unit: It uses magnetic Janus particles and magnetic field to separate water-insoluble organic matter from the wastewater. The magnetic Janus particles are NH2-Fe3O4-C8 particles. A part of the surface of the NH2-Fe3O4-C8 particles has amino groups, i.e., hydrophilic parts, and a part of the surface has C8 groups, i.e., hydrophobic parts obtained by modification with n-octyltriethoxysilane. The amount of the magnetic Janus particles relative to the wastewater containing organic pollutants is 0.01wt%-20wt%; Distillation unit: used to separate part of the dissolved organic matter in the wastewater; Biochemical treatment unit: used to degrade some organic matter in dissolved form; Ozone catalytic oxidation unit: used for catalytic oxidation of dissolved and difficult-to-degrade organic matter; In the oil-water separation unit, the magnetic Janus particle droplets are migrated and / or enriched by the action of a magnetic field to separate water-insoluble organic matter; The magnetic Janus particle droplets are dispersed phases formed by magnetic Janus particles coating water-insoluble organic matter in an emulsion obtained by emulsifying the wastewater using magnetic Janus particles as a solid emulsifier.

4. The processing device according to claim 3, characterized in that The oil-water separation unit includes a magnetic control oil-water separation device, and the magnetic control oil-water separation device includes a container capable of containing wastewater; and A magnet is configured to generate a magnetic force on the magnetic Janus particle emulsion droplets in the container.

5. The processing device according to claim 4, characterized in that The magnet may be fixedly configured or configured to be movable or rotatable.

6. The processing device according to any one of claims 3 to 5, characterized in that: The distillation unit comprises a rectification column and a condenser; The biochemical treatment unit comprises an anoxic tank, an aerobic tank and a sedimentation tank; the anoxic tank is provided with a water inlet, a lifting pump and a grid; the aerobic tank is provided with an inlet weir, an aeration device, a reflux device, an outlet weir and biological fillers; The ozone catalytic oxidation unit comprises a control cabinet, a circulating water reservoir, a three-stage aeration tower and an ozone generator, wherein the three-stage aeration tower is loaded with a catalyst.

7. A method for treating wastewater containing organic pollutants using the treatment equipment according to any one of claims 3 to 6, comprising: A step of separating water-insoluble organic matter from the wastewater by using magnetic Janus particles and a magnetic field; The step of distilling the treated liquid obtained in the previous step to separate and recover part of the dissolved organic matter in the wastewater; The treatment liquid obtained in the previous step is subjected to biochemical treatment to degrade part of the dissolved organic matter in the wastewater by using microorganisms; The treated liquid obtained in the previous step is subjected to ozone catalytic oxidation to oxidize dissolved and difficult-to-degrade organic matter in the wastewater.

Images