Organic wastewater treatment system and method

Abstract

The present invention provides an organic wastewater treatment system and method. The organic wastewater treatment system provided by the present application includes: a low-temperature volatilization unit, a primary oxidation degradation unit, a dissolution separation unit, a secondary oxidation degradation unit and a solid-liquid separation unit. The organic wastewater treatment system provided by the present application efficiently treats the organic wastewater to be treated through the low-temperature volatilization unit, the primary oxidation degradation unit, the dissolution separation unit, the secondary oxidation degradation unit and the solid-liquid separation unit connected in sequence. Not only is the process simple, the wastewater treatment efficiency is high, and it is not affected by the wastewater quality and output fluctuations, but also it can remove highly polar and difficult to oxidize organic impurities to obtain an inorganic metal ion solution, and at the same time it can also recover volatile organic matter and oxidized volatiles, thereby realizing the added value of the chemical energy of organic wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to an organic wastewater treatment system and method. Background Art

[0002] The treatment of high-concentration organic wastewater (COD ≥ 5000mg / L) has long been a common problem in the fields of metallurgy, environment, etc. The various components in the wastewater are complex, with high content of toxic and harmful substances, including organic pollutants, metal salts, anions, etc., and poor biochemical activity. The treatment cost is high, the process is complicated, the treatment time is long, and the treatment effect is greatly affected by the output water quality and output fluctuations. In particular, when it comes to the deep treatment of difficult-to-treat pollutants, the treatment is more difficult.

[0003] At present, the main treatment methods for high-concentration organic wastewater are physical, chemical, biochemical methods and their combined processes. Existing physical treatment methods are still mainly based on adsorption methods, and cheap and highly selective adsorption materials are the main research and development direction, but overall, their removal rate of organic matter is not high, and chemical or biochemical re-treatment is still required in the future, and the adsorption materials are prone to inactivation and loss. The reported chemical methods for treating wastewater include incineration and wet oxidation. The high-temperature incineration method is limited by high energy consumption, and wet oxidation treatment is still the preferred option for wastewater treatment. The reported wastewater oxidation treatment methods include ozone oxidation, Fenton reagent method, photocatalytic oxidation decomposition method, electrochemical micro-electrolysis oxidation method, microwave catalytic wet oxidation method, chlorine dioxide oxidation method, etc. Most of these methods use strong oxidizing oxidants as pollutant degradation agents, but due to the high cost of the agents, large investment, and poor stability of the system treatment effect, their application in high-organic concentration wastewater is limited. The defects of biochemical methods for treating wastewater mainly lie in the fact that the activity of biological communities is significantly affected by toxic substances in the wastewater, and it is basically unable to directly degrade high-concentration wastewater. Some organic matter is often difficult to degrade in biochemical treatment of diluted wastewater. In addition, the typical aerobic / anaerobic combined biochemical degradation process has difficulty in process coupling and slow biochemical degradation rate.

[0004] From the perspective of existing high-concentration organic wastewater treatment technology, the problems that need to be improved are mainly manifested in: 1) The adaptability to water quality and water volume fluctuations needs to be strengthened. For example, patent CN104803463 provides a CaCO 3 Powder adsorption of benzene-containing organic matter and then high-temperature treatment of solid wastewater treatment method, this method is to solid adsorption of organic matter removed by roasting treatment, which is limited by the need to use a large amount of CaCO 31) Raw materials have poor adaptability to large amounts of wastewater; 2) The utilization rate of chemical energy in wastewater and the treatment cost need to be reduced; 3) The deep purification of pollutants that are difficult to treat with conventional biological / chemical methods. Therefore, it is necessary to develop and explore more efficient, economical, and non-secondary pollution methods to treat wastewater with high organic concentrations.

[0005] From the perspective of resource utilization, many technologies for high-concentration wastewater have been reported, such as the patent CN108793551A, which uses high temperature and high pressure to treat soluble nitrite in V 2 O 5 / SBA-15 catalyzes rapid deep oxidation of organic matter. This method recovers solid salts and degrades organic pollutants, but the oxygen supply cost is relatively high. 2 The input reaches 2.5-10.0MPa. Among them, manganese oxide and its derivatives are used as effective oxidative receptors for the oxidation of organic pollutants and are used in the treatment process of various complex biomass materials. For example, patent CN104609597A provides a method for rapid degradation of organic pollutants, which utilizes bisulfite and KMnO 4 or MnO 2 Reaction; Patent CN105417616A uses industrial waste manganese dioxide to treat organic wastewater, and uses acidic manganese dioxide and activated carbon as treatment agents for organic wastewater. The treated water still contains some difficult-to-treat organic pollutants, and the obtained Mn cannot be directly used. 2+ Ionic solution.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The main purpose of the present invention is to provide an organic wastewater treatment system and method to solve the problems in the prior art of low efficiency, complex process flow, and significant impact of wastewater quality and output fluctuations, as well as difficulty in deep treatment of some highly polar and difficult to oxidize organic impurities during resource utilization.

[0008] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided an organic wastewater treatment system, which comprises: a low-temperature volatilization unit, a primary oxidation degradation unit, a dissolution separation unit, a secondary oxidation degradation unit and a solid-liquid separation unit; wherein the low-temperature volatilization unit comprises a low-temperature volatilization reactor, which is used to volatilize the organic wastewater to be treated at low temperature to obtain volatile organic matter and pretreated organic wastewater; the primary oxidation degradation unit comprises an oxidation degradation reactor, which is used to mix the pretreated organic wastewater with a first manganese-containing oxidant and a first dilute acid to form a slurry to be oxidized once, and then perform a primary oxidation degradation to obtain a primary oxidation degradation slurry and oxidized volatiles; the dissolution separation unit comprises a first solid-liquid separator and a dissolution separation device, wherein the first solid-liquid separator and the oxidation degradation reactor are connected to the first solid-liquid separator and the second solid-liquid separator. The kettle is connected to perform solid-liquid separation on the primary oxidation degradation slurry to obtain the primary oxidation degradation liquid and the first manganese-containing slag phase; the dissolution separation device is connected to the first solid-liquid separator to mix the primary oxidation degradation slurry with the organic solvent aerosol for selective dissolution reaction and separation of the aqueous phase and the organic phase to obtain the organic phase dissolved with organic impurities and the aqueous phase of the manganese-containing solution; the secondary oxidation degradation unit includes a secondary oxidation reactor, which is used to mix the aqueous phase of the manganese-containing solution with the second manganese-containing oxidant and the second dilute acid to form a liquid to be subjected to secondary oxidation degradation for secondary oxidation degradation to obtain the secondary oxidation degradation slurry; the solid-liquid separation unit includes a second solid-liquid separator, which is connected to the secondary oxidation reactor to perform solid-liquid separation on the secondary oxidation degradation slurry to obtain the second manganese-containing slag phase and the inorganic metal ion solution.

[0009] Furthermore, the low-temperature volatilization unit also includes a first condensation absorption tower, a first gas collector and a first organic solution collection box. The first condensation absorption tower is connected to the low-temperature volatilization reactor to condense volatile substances to obtain a first non-condensable gas and a first organic solution; the first gas collector is connected to the gas phase outlet of the first condensation absorption tower to collect the first non-condensable gas; the first organic solution collection box is connected to the liquid phase outlet of the first condensation absorption tower to collect the first organic solution.

[0010] Furthermore, the first oxidative degradation unit also includes a first manganese-containing oxidant feeding device, a first dilute acid feeding device, a slurry mixing device, a second condensation absorption tower, a second gas collector and a second organic solution collecting box; the slurry mixing device is arranged on the pipeline between the low-temperature volatilization reactor and the oxidative degradation reactor, and is used to mix the pretreated organic wastewater with the first manganese-containing oxidant and the first dilute acid into a slurry to be oxidized once; the first manganese-containing oxidant feeding device is connected to the slurry mixing device, and is used to provide the first manganese-containing oxidant to the slurry mixing device, and the first dilute acid feeding device is also connected to the slurry mixing device, and is used to provide the first dilute acid to the slurry mixing device; the second condensation absorption tower is connected to the oxidative degradation reactor, and is used to condense the oxidized volatiles to obtain a second non-condensable gas and a second organic solution; the second gas collector is connected to the gas phase outlet of the second condensation absorption tower, and is used to collect the second non-condensable gas; the second organic solution collecting box is connected to the liquid phase outlet of the second condensation absorption tower, and is used to collect the second organic solution.

[0011] Furthermore, the dissolution and separation unit also includes a bubble generator, an aerosol generator, a gas supply device, an organic solvent mixer, an organic solvent distillation device, a third organic solution collection box and a fourth organic solution collection box; the aerosol generator is connected to the dissolution and separation device to provide organic solvent aerosol to the dissolution and separation device, and the gas supply device is connected to the aerosol generator to provide gas to the aerosol generator; the organic solvent mixer is also connected to the aerosol generator to provide organic solvent to the aerosol generator; the bubble generator is arranged on the dissolution and separation device to explode the organic solvent aerosol in the dissolution and separation device; the organic solvent distillation device is connected to the dissolution and separation device to distill the organic phase of the dissolved organic impurities to obtain a distillation solvent and a residual liquid, the third organic solution collection box is connected to the gas phase outlet of the organic solvent distillation device to collect the distillation solvent, and the fourth organic solution collection box is connected to the liquid phase outlet of the organic solvent distillation device to collect the residual liquid; the dissolution and separation unit also includes a first slag phase collection box, which is connected to the first solid-liquid separator to collect the first manganese-containing slag phase.

[0012] Furthermore, the secondary oxidation degradation unit also includes a second manganese-containing oxidant feeding device and a second dilute acid feeding device; the second manganese-containing oxidant feeding device is connected to the secondary oxidation reactor for providing a second manganese-containing oxidant to the secondary oxidation reactor, and the second dilute acid feeding device is also connected to the secondary oxidation reactor for providing the second dilute acid to the secondary oxidation reactor.

[0013] Furthermore, in the solid-liquid separation unit, the second solid-liquid separator is also connected to the oxidative degradation reactor to return the second manganese-containing slag phase to the oxidative degradation reactor; the solid-liquid separation unit also includes a second slag phase collection box and an inorganic metal ion solution collection box, the second slag phase collection box is connected to the second solid-liquid separator for collecting the second manganese-containing slag phase, and the inorganic metal ion solution collection box is also connected to the second solid-liquid separator for collecting the inorganic metal ion solution.

[0014] According to another aspect of the present invention, a method for treating organic wastewater is also provided, and the method for treating organic wastewater comprises: step S1, volatilizing the organic wastewater to be treated at low temperature to obtain volatile organic matter and pretreated organic wastewater; step S2, mixing the pretreated organic wastewater with a first manganese-containing oxidant and a first dilute acid to form a slurry to be oxidized once, and performing a primary oxidation degradation to obtain a primary oxidation degradation slurry and oxidized volatiles; step S3, performing solid-liquid separation on the primary oxidation degradation slurry to obtain a first manganese-containing slag phase and a primary oxidation degradation feed liquid, mixing the first oxidation degradation feed liquid with an organic solvent aerosol to perform a selective dissolution reaction and performing aqueous phase and organic phase separation to obtain an organic phase dissolving organic impurities and an aqueous phase of a manganese-containing solution; step S4, performing secondary oxidation degradation on the slurry to be oxidized twice by mixing the aqueous phase of the manganese-containing solution with a second manganese-containing oxidant and a second dilute acid to obtain a secondary oxidation degradation slurry; step S5, performing solid-liquid separation on the secondary oxidation degradation slurry to obtain a second manganese-containing slag phase and a metal ion solution.

[0015] Furthermore, in step S1, the temperature of low-temperature volatilization is 60-95° C., and the time is 20-30 minutes.

[0016] Furthermore, step S1 further comprises condensing and absorbing the volatile organic matter to obtain a first non-condensable gas and a first organic solution; and / or, in step S2, the temperature of the primary oxidation degradation is 70 to 250° C. and the time is 10 to 360 minutes.

[0017] Further, after the H + The concentration is 0.5-3 mol / L, and the H in the slurry is degraded by primary oxidation. + The concentration is 10 -3 ~10 2 mol / L.

[0018] Furthermore, the mass ratio of the first manganese-containing oxidant to the pretreated organic wastewater is 1:(2-10).

[0019] Furthermore, step S2 further comprises condensing and absorbing the oxidized volatiles to obtain a second non-condensable gas and a second organic solution.

[0020] Further, in step S3, the organic solvent aerosol is a microbubble organic solvent aerosol, the diameter of the microbubble is 0.001-100 μm, and the gas in the organic solvent aerosol includes CO 2 、N 2 or at least one of an inert gas.

[0021] Furthermore, the organic solvent aerosol is prepared by passing an organic solvent through an aerosol generator; preferably, the organic solvent is a weakly polar organic solvent and / or a non-polar organic solvent, and is insoluble or slightly soluble in water;

[0022] Furthermore, the weakly polar organic solvent includes at least one of ether compounds or alkane compounds; and the non-polar organic solvent includes at least one of carbon tetrachloride, carbon disulfide, alkane compounds, kerosene, benzene and non-polar derivatives thereof.

[0023] Furthermore, the organic solvent aerosol is pressed into the primary oxidation degradation slurry at a pressure of 0.12-0.6 MPa for mixing.

[0024] Further, the temperature of the selective dissolution reaction is -10 to 90°C, the time is 0.5 to 20 minutes, and the pressure is 0.01 to 0.09 MPa;

[0025] Furthermore, the selective dissolution reaction is carried out under the action of ultrasound, the frequency of the ultrasound wave is 20kHz to 60kHz, and the intensity is 20 to 80W / cm 2 ;

[0026] Furthermore, in the primary degradation liquid, COD cr The content is 0.5~10g / L, Mn 2+ Content is 2.0~120g / L;

[0027] Furthermore, step S3 also includes distilling the organic phase containing dissolved organic impurities to obtain a distillation solvent and a raffinate.

[0028] Furthermore, in step S4, the temperature of the secondary oxidation degradation is 60 to 90° C., and the reaction time is 20 to 30 minutes.

[0029] Furthermore, the mass ratio of the second manganese-containing oxidant to the aqueous phase of the manganese-containing solution is 1:(2-10).

[0030] Further, after the H + The concentration is 0.5~3mol / L.

[0031] Furthermore, in step S5, the second manganese-containing slag phase returns to step S2 to be mixed with the first manganese-containing oxidant.

[0032] Furthermore, the COD in the organic wastewater to be treatedcr ≥5 g / L;

[0033] Furthermore, the particle sizes of the first manganese-containing oxidant and the second manganese-containing oxidant are each independently ≤0.15 mm, and the first manganese-containing oxidant and the second manganese-containing oxidant are each independently selected from pyrolusite, manganese nodules or MnO-containing 2 at least one of the waste materials;

[0034] Furthermore, the first dilute acid and the second dilute acid are each independently selected from at least one of sulfuric acid, hydrochloric acid, nitric acid or industrial waste acid, preferably sulfuric acid.

[0035] By applying the technical solution of the present application, the organic wastewater treatment system provided by the present application efficiently treats the organic wastewater to be treated through a low-temperature volatilization unit, a primary oxidation degradation unit, a dissolution separation unit, a secondary oxidation degradation unit and a solid-liquid separation unit connected in sequence. Not only is the process simple, the wastewater treatment efficiency is high, and it is not affected by the wastewater quality and output fluctuations, but it can also remove highly polar and difficult-to-oxidize organic impurities to obtain an inorganic metal ion solution, and at the same time it can also recover volatile organic matter and oxidized volatiles, thereby realizing the added value of the chemical energy of the organic wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0037] Figure 1 A schematic flow chart of an organic wastewater treatment system provided according to Example 1 of the present invention is shown.

[0038] The above drawings include the following reference numerals:

[0039] 10. Low-temperature volatilization reactor; 11. First condensation absorption tower; 12. First gas collector; 13. First organic solution collection box; 20. Oxidation degradation reactor; 21. First manganese-containing oxidant feeding device; 22. First dilute acid feeding device; 23. Slurry mixing device; 24. Second condensation absorption tower; 25. Second gas collector; 26. Second organic solution collection box; 30. Dissolution separation device; 31. Bubble assistant; 32. Aerosol generator; 33. Gas supply device; 34. Organic solvent mixer; 35. Organic solvent distillation device; 36. Third organic solution collection box; 37. Fourth organic solution collection box; 38. First solid-liquid separator; 39. First slag phase collection box; 40. Secondary oxidation reactor; 41. Second manganese-containing oxidant feeding device; 42. Second dilute acid feeding device; 50. Second solid-liquid separator; 51. Second slag phase collection box; 52. Inorganic metal ion solution collection box. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0041] As analyzed in the background technology of this application, the shortcomings of existing high-concentration organic wastewater treatment technologies are as follows: (1) Physical adsorption treatment, low organic matter removal / degradation rate, degradation rate is often less than 80%, high-concentration wastewater is difficult to feed, adsorption materials are difficult to analyze, and subsequent treatment still requires chemical oxidation or biological oxidation for re-treatment, and the treatment process is long. (2) Chemical oxidation treatment, large amount of oxidant is used, and the cost of the agent is high; it is not adaptable to large fluctuations in wastewater; after initial treatment, the problem of deep treatment is prominent, and the wet deep treatment of low-concentration difficult-to-treat pollutants is difficult, and the operation of adding catalysis / deep oxidation is high. (3) Biochemical treatment, microorganisms are restricted by the concentration of toxic species in the wastewater and cannot treat high-concentration wastewater; biochemical treatment after wastewater dilution is affected by the complex components of the wastewater, and the degradation process is slow, cumbersome, and the operation rate is low. In addition, the problem of deep degradation of pollutants is also prominent. In order to solve the problems of low efficiency, complex process flow, and significant impact of wastewater quality and output fluctuations in existing organic wastewater treatment, as well as difficulty in deep treatment of some highly polar and difficult to oxidize impurities during resource utilization, the present application provides an organic wastewater treatment system and method.

[0042] In a typical embodiment of the present application, an organic wastewater treatment system is provided, such as Figure 1As shown, the system includes: a low-temperature volatilization unit, a primary oxidation degradation unit, a dissolution separation unit, a secondary oxidation degradation unit and a solid-liquid separation unit, wherein the low-temperature volatilization unit includes a low-temperature volatilization reactor 10, which is used to volatilize the organic wastewater to be treated at low temperature to obtain volatile organic matter and pretreated organic wastewater; the primary oxidation degradation unit includes an oxidation degradation reactor 20, which is used to perform a primary oxidation degradation on the pretreated organic wastewater, the first manganese-containing oxidant and the first dilute acid mixed to form a slurry to be oxidized, to obtain a primary oxidation degradation slurry and oxidized volatiles; the dissolution separation unit includes a first solid-liquid separator 38 and a dissolution separation device 30, wherein the first solid-liquid separator 38 is connected to the oxidation degradation reactor 20, and is used to volatilize the primary oxidation degradation slurry. The slurry is subjected to solid-liquid separation to obtain a primary oxidation degradation liquid and a first manganese-containing slag phase. The dissolution separation device 30 is connected to the first solid-liquid separator 38, and is used to mix the primary oxidation degradation liquid with the organic solvent aerosol for selective dissolution reaction and to separate the aqueous phase and the organic phase to obtain an organic phase dissolving organic impurities and an aqueous phase containing manganese solution; the secondary oxidation degradation unit includes a secondary oxidation reactor 40, which is used to perform secondary oxidation degradation on the slurry to be secondary oxidized, which is mixed with the aqueous phase of the manganese-containing solution, the second manganese-containing oxidant and the second dilute acid, to obtain a secondary oxidation degradation slurry; the solid-liquid separation unit includes a second solid-liquid separator 50, which is connected to the secondary oxidation reactor 40, and is used to perform solid-liquid separation on the secondary oxidation degradation slurry to obtain a second manganese-containing slag phase and an inorganic metal ion solution.

[0043] By applying the technical solution of the present application, the organic wastewater treatment system provided by the present application efficiently treats the organic wastewater to be treated through a low-temperature volatilization unit, a primary oxidation degradation unit, a dissolution separation unit, a secondary oxidation degradation unit and a solid-liquid separation unit connected in sequence. Not only is the process simple, the wastewater treatment efficiency is high, and it is not affected by the wastewater quality and output fluctuations, but it can also remove highly polar and difficult-to-oxidize organic impurities to obtain an inorganic metal ion solution, and at the same time it can also recover volatile organic matter and oxidized volatiles, thereby realizing the added value of the chemical energy of the organic wastewater.

[0044] In view of the fact that the volatile organic matter contains small molecular phenolic compounds, ether compounds and free ammonia substances, in order to facilitate the classification and recovery of volatile organic matter, it is preferred that the low-temperature volatilization unit also includes a first condensation absorption tower 11, a first gas collector 12 and a first organic solution collection box 13. The first condensation absorption tower 11 is connected to the low-temperature volatilization reactor 10, and is used to condense the volatile organic matter, so that the volatile matter in the volatile organic matter is condensed and absorbed into the first organic solution, and the uncondensed volatile organic matter is discharged from the first condensation absorption tower 11 in the form of a first non-condensable gas. The first gas collector 12 is connected to the gas phase outlet of the first condensation absorption tower 11, and is used to collect the first non-condensable gas; the first organic solution collection box 13 is connected to the liquid phase outlet of the first condensation absorption tower 11, and is used to collect the first organic solution.

[0045] In order to further improve the efficiency of the primary oxidation degradation, the primary oxidation degradation unit preferably also includes a first manganese-containing oxidant feeding device 21, a first dilute acid feeding device 22 and a slurry mixing device 23. The first manganese-containing oxidant feeding device 21 is connected to the slurry mixing device 23, and is used to provide the first manganese-containing oxidant to the slurry mixing device 23. The first dilute acid feeding device 22 is also connected to the slurry mixing device 23, and is used to provide the first dilute acid to the slurry mixing device 23; the slurry mixing device 23 is arranged on the pipeline between the low-temperature volatilization reactor 10 and the oxidation degradation reactor 20, and is used to mix the pretreated organic wastewater with the first manganese-containing oxidant and the first dilute acid into a slurry to be oxidized once, thereby improving the dispersion uniformity of each material in the primary slurry to be oxidized, so that it is transported to the oxidation degradation reactor 20 to improve the efficiency of the primary oxidation degradation.

[0046] In order to facilitate the classification and recovery of oxidized volatiles, it is preferred that the primary oxidative degradation unit further includes a second condensation absorption tower 24, a second gas collector 25, and a second organic solution collection box 26. The second condensation absorption tower 24 is connected to the oxidative degradation reactor 20 and is used to condense the oxidized volatiles, so that the volatiles in the oxidized volatiles are condensed and absorbed into a second organic solution, and the uncondensed oxidized volatiles are discharged from the second condensation absorption tower 24 in the form of a second non-condensable gas. The second gas collector 25 is connected to the gas phase outlet of the second condensation absorption tower 24 to collect the second non-condensable gas; the second organic solution collection box 26 is connected to the liquid phase outlet of the second condensation absorption tower 24 to collect the second organic solution.

[0047] In order to further improve the removal rate of highly polar and difficult to oxidize organic impurities in the primary oxidation degradation liquid, the dissolution and separation unit preferably also includes a bubble explosion assistant 31, an aerosol generator 32, a gas supply device 33 and an organic solvent mixer 34. The gas supply device 33 is connected to the aerosol generator 32 to provide gas to the aerosol generator 32; the organic solvent mixer 34 is also connected to the aerosol generator 32 to provide a mixed organic solvent to the aerosol generator 32; the aerosol generator 32 is connected to the dissolution and separation device 30 to provide an organic solvent aerosol to the dissolution and separation device 30. The bubble explosion assistant 31 is arranged on the dissolution and separation device 30 to explode the organic solvent aerosol in the dissolution and separation device 30.

[0048] In order to further improve the utilization rate of the organic solvent, it is preferred that the dissolution and separation unit also includes an organic solvent distillation device 35, a third organic solution collecting box 36 and a fourth organic solution collecting box 37. The organic solvent distillation device 35 is connected to the dissolution and separation device 30, and is used to distill the organic phase of the dissolved organic impurities to obtain a distillation solvent and a residual liquid. The third organic solution collecting box 36 is connected to the organic solvent distillation device 35 to collect the distillation solvent. The fourth organic solution collecting box 37 is also connected to the organic solvent distillation device 35 to collect the residual liquid.

[0049] In order to facilitate the collection of the first manganese-containing organic phase, the dissolution separation unit preferably further includes a first slag phase collection box 39, which is connected to the first solid-liquid separator 38 and is used to collect the first manganese-containing slag phase.

[0050] In order to further improve the comprehensive utilization rate of the first manganese-containing slag phase, it is preferred that the first manganese-containing slag phase is used to prepare silicon-based materials.

[0051] In order to further improve the secondary oxidation degradation efficiency, the secondary oxidation degradation unit preferably also includes a second manganese-containing oxidant feeding device 41 and a second dilute acid feeding device 42. The second manganese-containing oxidant feeding device 41 is connected to the secondary oxidation reactor 40 for providing a second manganese-containing oxidant to the secondary oxidation reactor 40, and the second dilute acid feeding device 42 is also connected to the secondary oxidation reactor 40 for providing a second dilute acid to the secondary oxidation reactor 40.

[0052] In order to further improve the comprehensive utilization rate of the second manganese-containing slag phase, it is preferred that in the solid-liquid separation unit, the second solid-liquid separator 50 is also connected to the oxidative degradation reactor 20 to return the second manganese-containing slag phase to the oxidative degradation reactor 20 as the first manganese-containing oxidant.

[0053] In order to further improve energy recovery, the solid-liquid separation unit preferably further includes a second slag phase collection box 51 and an inorganic metal ion solution collection box 52. The second slag phase collection box 51 is connected to the second solid-liquid separator 50 for collecting the second manganese-containing slag phase, and the inorganic metal ion solution collection box 52 is also connected to the second solid-liquid separator 50 for collecting the inorganic metal ion solution. The second manganese-containing slag phase collection box is preferably connected to the first manganese-containing oxidant feeding device 21, so that the manganese-containing oxidant is added to the oxidative degradation reactor 20 as a manganese-containing oxidant through the first manganese-containing oxidant feeding device 21 for recycling.

[0054] In a second typical embodiment of the present application, a method for treating organic wastewater is also provided, which includes: step S1, volatilizing the organic wastewater to be treated at low temperature to obtain volatile organic matter and pretreated organic wastewater; step S2, subjecting the pretreated organic wastewater to a slurry to be oxidized once, which is mixed with a first manganese-containing oxidant and a first dilute acid, to a first oxidation degradation slurry and oxidized volatiles; step S3, subjecting the first oxidation degradation slurry to solid-liquid separation to obtain a first manganese-containing slag phase and a first oxidation degradation liquid, mixing the first oxidation degradation liquid with an organic solvent aerosol for selective dissolution reaction and separating the aqueous phase and the organic phase to obtain an organic phase in which organic impurities are dissolved and an aqueous phase of a manganese-containing solution; step S4, subjecting the aqueous phase of the manganese-containing solution to a slurry to be oxidized twice, which is mixed with a second manganese-containing oxidant and a second dilute acid, to a second oxidation degradation slurry; step S5, in step S5, subjecting the secondary oxidation degradation slurry to solid-liquid separation to obtain a second manganese-containing slag phase and a metal ion solution.

[0055] The organic wastewater treatment method provided in the present application sequentially performs low-temperature volatilization, primary oxidation degradation, selective dissolution separation, secondary oxidation degradation and solid-liquid separation on the organic wastewater to be treated. Not only is the process simple, the wastewater treatment efficiency is high and it is not affected by wastewater quality and output fluctuations, but it can also remove highly polar and difficult-to-oxidize organic impurities to obtain an inorganic metal ion solution, and at the same time it can also recover volatile organic matter and oxidized volatiles, thereby realizing the added value of the chemical energy of the organic wastewater.

[0056] The above-mentioned organic wastewater to be treated is high-concentration organic wastewater. Preferably, in the organic wastewater to be treated, COD cr ≥5g / L.

[0057] In order to further improve the efficiency of low-temperature volatilization, step S1 is preferably performed at a temperature of 60 to 95°C for 20 to 30 minutes to volatilize and separate volatile organic matter (such as small molecular phenols, ethers, etc.) and free ammonia, etc. to obtain preheated pretreated organic wastewater and volatile matter.

[0058] In order to classify and recycle the volatile organic matter, preferably step S1 also includes condensing and absorbing the volatile organic matter, so that some volatile components are condensed and absorbed to obtain a first organic solution and a first non-condensable gas.

[0059] In order to further improve the adequacy of oxidative degradation, it is preferred that step S2 adjusts the amount of the first dilute acid so that the H + The concentration is 0.5-3 mol / L, so as to deeply oxidize and degrade the slurry to be oxidized, and make the H + The concentration is 10 -3 ~10 2 mol / L.

[0060] In order to further improve the efficiency of oxidative degradation, it is preferred that the temperature of the primary oxidative degradation is 70 to 250° C. and the time is 10 to 360 min.

[0061] In order to promote the full oxidation and degradation of the pretreated organic wastewater, the mass ratio of the first manganese-containing oxidant to the pretreated organic wastewater is preferably 1: (2-10), so as to facilitate the removal of most of the organic matter in the pretreated organic wastewater by MnO 2 and its derivatives (MnO·OH, Mn 3+ ) is oxidized to CO 2 , H 2 O、NO 3 - 、SO 4 2- etc. to obtain a primary oxidation degradation slurry.

[0062] Preferably, the weight ratio of COD in the pretreated organic wastewater to tetravalent manganese in the first manganese-containing oxidant is (0.1-0.3):1, so as to further improve the oxidative degradation removal rate of COD in the pretreated organic wastewater.

[0063] In order to further simplify the process flow of the above-mentioned primary oxidative degradation, it is preferred that the primary oxidative degradation is carried out in the oxidative degradation reactor 20, and the primary oxidized slurry is stirred at an intensity of 200 to 600 r / min, and the oxidized volatiles are extracted from the top of the oxidative degradation reactor 20 and subjected to condensation and absorption treatment to obtain a second non-condensable gas and a second organic solution.

[0064] The above-mentioned primary oxidation degradation can be carried out continuously at normal pressure, or by pressurized intermittent closed reaction. When the operation is carried out continuously at normal pressure, the oxidized volatiles are continuously taken out for condensation and absorption treatment. When the operation is carried out intermittently in closed reaction, the oxidized volatiles are further condensed and absorbed after the reaction is completed.

[0065] In the above step S3, in order to facilitate the removal of highly polar and difficult-to-treat organic impurities in the primary oxidative degradation slurry, it is preferred to first separate the solids in the primary oxidative degradation slurry by filter pressing and then carry out a selective dissolution reaction to obtain a first manganese-containing slag phase and a primary oxidative degradation liquid, and the first manganese-containing slag phase is used to prepare silicon-based materials.

[0066] In order to further improve the removal rate of highly polar and difficult-to-treat organic impurities in the primary oxidation degradation liquid, it is preferred that in step S3, the organic solvent aerosol is a microbubble organic solvent aerosol, the diameter of the microbubble is 0.001 to 100 μm, and the gas of the organic solvent aerosol is a non-oxidizing gas, including but not limited to CO 2 、N 2 Or at least one of the inert gases (helium or argon, etc.).

[0067] The organic solvent aerosol is preferably prepared by passing an organic solvent through or through an aerosol generator 32. From the perspective of improving the solubility of strongly polar and difficult-to-handle organic impurities, the organic solvent is preferably a weakly polar organic solvent and / or a non-polar organic solvent, and is insoluble or slightly soluble in water. Slightly soluble means that the solubility s of the organic solvent in 100g of water satisfies 0.01g<s<1g, and insoluble means that the solubility s of the organic solvent in 100g of water satisfies s≤0.01g.

[0068] Non-polar organic solvents include but are not limited to benzene and its non-polar derivatives, carbon tetrachloride, carbon disulfide, imidazoline, alkane (such as pentane, hexane, etc.) solvents, and any one or more mixed organic solvents of kerosene; weak polar solvents include but are not limited to any one or more mixed organic solvents of ether (such as diethyl ether, propyl ether, petroleum ether, etc.) solvents or alkane (such as N-methylpyrrolidone, 1-benzyl-2-pyrrolidone, etc.) solvents.

[0069] In order to improve the mixing efficiency of the solvent aerosol and the primary oxidative degradation liquid, the solvent aerosol is preferably pressed into the primary oxidative degradation liquid for mixing. The pressure of the solvent aerosol is 0.12 to 0.8 MPa, and the pressure for the selective dissolution reaction is preferably 0.01 to 0.09 MPa.

[0070] In order to further improve the removal efficiency of organic impurities, the temperature of the selective dissolution reaction is preferably -10 to 90°C and the time is 0.5 to 20 min.

[0071] In order to further improve the efficiency of selective dissolution and separation, the selective dissolution reaction is preferably carried out under the action of ultrasound, with a wave frequency of 20kHz to 60kHz and an intensity of 20 to 80W / cm 2 .

[0072] In the above-mentioned selective dissolution reaction process, the selective competitive dissolution and separation of highly polar and difficult-to-handle organic impurities is achieved by pressing the prepared organic solvent aerosol (microbubbles) into the primary oxidative degradation liquid in a negative pressure state in a manner of increasing pressure. The pressed aerosol is fully in contact with the primary oxidative degradation liquid, and the aerosol (microbubbles) are rapidly exploded by the pressure difference or ultrasonic cavitation. On the one hand, the bubble surface is broken, increasing the contact probability between the organic solvent and the organic impurities in the solution. Secondly, the foam brittleness enhances the surface activity of the organic solvent, strengthens the ability of the organic solvent to compete with the aqueous phase of the solution to dissolve organic impurities, and makes it easier for the organic impurities to be dissolved into the organic solvent. In addition, since the mutual solubility of the organic solvent used and the metal ion-rich aqueous phase is weak, the organic solvent phase that dissolves the organic impurities will move relative to each other and aggregate relative to each other, promoting the directional enrichment of stable organic impurities in the organic solvent phase and the inorganic metal ion solution aqueous phase, and then separating the organic solvent phase from the inorganic metal ion solution.

[0073] In order to further reduce energy consumption, the organic phase containing dissolved organic impurities is preferably separated from the aqueous phase of the manganese-containing solution by a layering method, preferably, by an up-and-down splitting method.

[0074] In order to further improve the comprehensive utilization rate of energy, preferably step S3 also includes distilling the organic phase containing dissolved organic impurities to obtain a distillation solvent and a raffinate, and the distillation solvent can be recycled for the preparation of the organic solvent aerosol.

[0075] The specific content of each component in the above-mentioned primary degradation liquid is not specifically limited, and COD cr The content is 0.5~10g / L, Mn 2+ The content is 2.0~120g / L.

[0076] In order to further improve the efficiency of secondary oxidation degradation, preferably, in step S4, the temperature of the secondary oxidation degradation is 60-90° C. and the reaction time is 20-30 min.

[0077] In order to promote more complete secondary oxidation degradation, the mass ratio of the second manganese-containing oxidant to the aqueous phase of the manganese-containing solution is preferably 1:(2-10).

[0078] In order to further improve the efficiency of oxidative degradation, it is preferred to adjust the amount of H in the slurry to be secondary oxidized by controlling the amount of the second dilute acid. + The concentration is 0.5~3mol / L.

[0079] In order to further improve the energy recovery rate, preferably, step S5, the second manganese-containing phase obtained by solid-liquid separation is returned to step S2 and mixed with the first manganese-containing oxidant to continue to be recycled as a manganese-containing oxidant.

[0080] In order to further improve the efficiency of oxidative degradation, it is preferred that the particle sizes of the first manganese-containing oxidant and the second manganese-containing oxidant are each independently ≤0.15 mm, and the first manganese-containing oxidant and the second manganese-containing oxidant are each independently selected from pyrolusite, manganese nodules or MnO-containing 2 Any mixture of one or more of the waste materials.

[0081] The specific types of the first dilute acid and the second dilute acid are not particularly limited, and can be used to oxidize H in the slurry. + The first dilute acid and the second dilute acid may be any dilute acid solution, including but not limited to sulfuric acid, hydrochloric acid, nitric acid or a mixed acid formed by any one or more of industrial waste acid. From the perspective of improving the oxidative degradation efficiency, it is preferred that both the first dilute acid and the second dilute acid are sulfuric acid.

[0082] The organic wastewater treatment method provided in this application has at least the following beneficial effects:

[0083] (1) The present invention has obvious advantages in treating high-concentration organic wastewater by sequentially volatilizing at low temperature, first oxidation degradation, selective dissolution separation and second oxidation degradation. The oxidation effect of volatile organic matter with manganese-containing oxidants is not ideal, and preferential volatilization separation can recover this part of organic matter; the vast majority of organic pollutants are degraded by first oxidation. 2 and MnO·OH, Mn 3+ Strong oxidizing property, the oxidation reaction product is basically CO 2 , H 2 O,CO 2 It can be used for subsequent primary oxidation degradation of the feed solution to adjust ion selective precipitation and pH and other processes; it selectively dissolves difficult-to-oxidize, highly polar organic impurities with organic solvents. After primary oxidation degradation with a manganese-containing oxidant, the organic pollutants in the solution are greatly reduced, most of which are large molecular organic matter that is difficult to treat. The competitive dissolution trend using organic solvents is relatively strong and the agent consumption is significantly reduced.

[0084] (2) By making full use of the cavitation effect of the instantaneous explosion of organic solvent aerosol (microbubbles), the solubility of organic solvent and organic impurities in the solution to be treated is enhanced, so that difficult-to-treat organic impurities can be selectively and directionally enriched from the primary oxidation degradation solution (containing a high-concentration inorganic ion solution), thereby simplifying the acidic oxidation process with manganese-containing oxidants and achieving the purpose of deep treatment of high-concentration organic wastewater.

[0085] (3) The treatment method uses low-cost manganese-containing oxidant, acid and organic solvent as treatment agents, and the organic solvent is recycled, making the treatment process cost low.

[0086] (4) It is suitable for treating various types of high-concentration organic wastewater and is less affected by wastewater quality and output fluctuations.

[0087] The beneficial effects of the present application will be further illustrated below in conjunction with embodiments.

[0088] Example 1

[0089] This embodiment provides an organic wastewater treatment system, such as Figure 1 As shown, the system includes a low-temperature volatilization unit, a primary oxidation degradation unit, a dissolution separation unit, a secondary oxidation degradation unit and a solid-liquid separation unit, wherein the low-temperature volatilization unit includes a low-temperature volatilization reactor 10, which is used to volatilize the organic wastewater to be treated at low temperature to obtain volatile organic matter and pretreated organic wastewater; the primary oxidation degradation unit includes an oxidation degradation reactor 20, which is used to perform a primary oxidation degradation on the pretreated organic wastewater, the first manganese-containing oxidant and the first dilute acid mixed into a slurry to be oxidized, to obtain a primary oxidation degradation slurry and oxidized volatiles; the dissolution separation unit includes a first solid-liquid separator 38 and a dissolution separation device 30, wherein the first solid-liquid separator 38 is connected to the oxidation degradation reactor 20, and is used to volatilize the primary oxidation degradation slurry Solid-liquid separation is performed to obtain a primary oxidation degradation liquid and a first manganese-containing slag phase. The dissolution separation device 30 is connected to the first solid-liquid separator 38, and is used to mix the primary oxidation degradation liquid with an organic solvent aerosol for selective dissolution reaction and to separate the aqueous phase and the organic phase to obtain an organic phase dissolving organic impurities and an aqueous phase containing a manganese solution. The secondary oxidation degradation unit includes a secondary oxidation reactor 40, which is used to perform secondary oxidation degradation on a slurry to be secondary oxidized that is mixed with the aqueous phase of the manganese-containing solution, a second manganese-containing oxidant and a second dilute acid, to obtain a secondary oxidation degradation slurry. The solid-liquid separation unit includes a second solid-liquid separator 50, which is connected to the secondary oxidation reactor 40, and is used to perform solid-liquid separation on the secondary oxidation degradation slurry to obtain a second manganese-containing slag phase and an inorganic metal ion solution.

[0090] The organic wastewater treatment system provided in this embodiment efficiently treats the organic wastewater to be treated by sequentially connecting a low-temperature volatilization unit, a primary oxidation degradation unit, a dissolution separation unit, a secondary oxidation degradation unit and a solid-liquid separation unit. Not only is the process simple, the wastewater treatment efficiency is high, and it is not affected by wastewater quality and output fluctuations, but it can also remove highly polar and difficult-to-oxidize organic impurities to obtain an inorganic metal ion solution, and at the same time it can also recover volatile organic matter and oxidized volatiles, thereby realizing the added value of the chemical energy of organic wastewater.

[0091] Since the volatile organic matter contains small molecular phenolic compounds, ether compounds and free ammonia substances, in order to facilitate the classification and recovery of volatile organic matter, the low-temperature volatilization unit also includes a first condensation absorption tower 11, a first gas collector 12 and a first organic solution collection box 13. The first condensation absorption tower 11 is connected to the low-temperature volatilization reactor 10, and is used to condense the volatile organic matter, so that the volatile matter in the volatile organic matter is condensed and absorbed into the first organic solution, and the uncondensed volatile organic matter is discharged from the first condensation absorption tower 11 in the form of a first non-condensable gas. The first gas collector 12 is connected to the gas phase outlet of the first condensation absorption tower 11, and is used to collect the first non-condensable gas; the first organic solution collection box 13 is connected to the liquid phase outlet of the first condensation absorption tower 11, and is used to collect the first organic solution.

[0092] In order to further improve the efficiency of primary oxidation degradation, the primary oxidation degradation unit also includes a first manganese-containing oxidant feeding device 21, a first dilute acid feeding device 22 and a slurry mixing device 23. The first manganese-containing oxidant feeding device 21 is connected to the slurry mixing device 23, and is used to provide the first manganese-containing oxidant to the slurry mixing device 23. The first dilute acid feeding device 22 is also connected to the slurry mixing device 23, and is used to provide the first dilute acid to the slurry mixing device 23; the slurry mixing device 23 is arranged on the pipeline between the low-temperature volatilization reactor 10 and the oxidation degradation reactor 20, and is used to mix the pretreated organic wastewater with the first manganese-containing oxidant and the first dilute acid into a slurry to be oxidized once, thereby improving the dispersion uniformity of each material in the primary slurry to be oxidized, so that it is transported to the oxidation degradation reactor 20 to improve the efficiency of the primary oxidation degradation.

[0093] In order to facilitate the classification and recovery of oxidized volatiles, the primary oxidative degradation unit further includes a second condensation absorption tower 24, a second gas collector 25 and a second organic solution collection box 26. The second condensation absorption tower 24 is connected to the oxidative degradation reactor 20 and is used to condense the oxidized volatiles so that the volatiles in the oxidized volatiles are condensed and absorbed into a second organic solution, and the uncondensed oxidized volatiles are discharged from the second condensation absorption tower 24 in the form of a second non-condensable gas. The second gas collector 25 is connected to the gas phase outlet of the second condensation absorption tower 24 to collect the second non-condensable gas; the second organic solution collection box 26 is connected to the liquid phase outlet of the second condensation absorption tower 24 to collect the second organic solution.

[0094] In order to further improve the removal rate of highly polar and difficult-to-oxidize organic impurities in the primary oxidation degradation liquid, the dissolution and separation unit also includes a bubble explosion assistant 31, an aerosol generator 32, a gas supply device 33 and an organic solvent mixer 34. The gas supply device 33 is connected to the aerosol generator 32 to provide gas to the aerosol generator 32; the organic solvent mixer 34 is also connected to the aerosol generator 32 to provide mixed organic solvent to the aerosol generator 32; the aerosol generator 32 is connected to the dissolution and separation device 30 to provide organic solvent aerosol to the dissolution and separation device 30. The bubble explosion assistant 31 is arranged on the dissolution and separation device 30 to explode the organic solvent aerosol in the dissolution and separation device 30.

[0095] In order to further improve the utilization rate of the organic solvent, the dissolution and separation unit is selected to also include an organic solvent distillation device 35, a third organic solution collecting box 36 and a fourth organic solution collecting box 37. The organic solvent distillation device 35 is connected to the dissolution and separation device 30, and is used to distill the organic phase of the dissolved organic impurities to obtain a distillation solvent and a residual liquid. The third organic solution collecting box 36 is connected to the organic solvent distillation device 35, and is used to collect the distillation solvent. The fourth organic solution collecting box 37 is also connected to the organic solvent distillation device 35, and is used to collect the residual liquid.

[0096] In order to facilitate the collection of the first manganese-containing organic phase, the dissolution separation unit further includes a first slag phase collection box 39, which is connected to the first solid-liquid separator 38 and is used to collect the first manganese-containing slag phase.

[0097] In order to further improve the comprehensive utilization rate of the first manganese-containing slag phase, the first manganese-containing slag phase can be recycled for preparing silicon-based materials.

[0098] In order to further improve the secondary oxidation degradation efficiency, the secondary oxidation degradation unit also includes a second manganese-containing oxidant feeding device 41 and a second dilute acid feeding device 42. The second manganese-containing oxidant feeding device 41 is connected to the secondary oxidation reactor 40 for providing a second manganese-containing oxidant to the secondary oxidation reactor 40. The second dilute acid feeding device 42 is also connected to the secondary oxidation reactor 40 for providing a second dilute acid to the secondary oxidation reactor 40.

[0099] In order to further improve energy recovery, the solid-liquid separation unit also includes a second slag phase collection box 51 and an inorganic metal ion solution collection box 52. The second slag phase collection box 51 is connected to the second solid-liquid separator 50 for collecting the second manganese-containing slag phase. The inorganic metal ion solution collection box 52 is also connected to the second solid-liquid separator 50 for collecting the inorganic metal ion solution.

[0100] In addition, the second manganese-containing slag phase collecting box is connected to the first manganese-containing oxidant feeding device 21 so that the manganese-containing oxidant is added into the oxidative degradation reactor 20 through the first manganese-containing oxidant feeding device 21 for recycling.

[0101] Example 2

[0102] This embodiment provides a method for treating organic wastewater, which uses the system provided in Example 1 to treat wastewater, including the following steps:

[0103] (1) Take a certain enterprise's high-concentration sulfuric acid wastewater containing benzene (COD concentration of 4.56×10 5 g / L, free H + Concentration 4.5×10 2 g / L), the wastewater was placed in a low-temperature volatilization reactor for volatilization separation, and the temperature was raised to 70°C for 120 min to obtain pretreated organic wastewater (COD concentration of 1.23×10 5 mg / L, free H + Concentration 1.5×10 2 g / L) and volatile organic matter, the volatile organic matter is passed into the first condensation absorption tower 11 for condensation absorption collection and recovery of volatile phenols to obtain a first non-condensable gas and a first organic solution, the first non-condensable gas is collected in the first gas collector 12, and the first organic solution is collected in the first organic solution collection box 13.

[0104] (2) Pre-treated organic wastewater and the first manganese slag (MnO 2 The mineral content accounts for 82%, the Mn grade is 14.6%, and the Fe grade is 10.7%) in a mass ratio of 2:1 and a first sulfuric acid solution with a mass concentration of 20% is added to the slurry mixing device 23 to mix into a first slurry to be oxidized (H + The concentration is 2.0 mol / L), the first slurry to be oxidized is added into the oxidative degradation reactor 20, and then stirred and leached for 120 min at a temperature of 150°C to obtain a primary oxidative degradation slurry and oxidized volatiles, the oxidized volatiles are discharged from the oxidative degradation reactor 20 into the second condensation absorption tower 24 for condensation absorption to obtain a second non-condensable gas and a second organic solution, the second non-condensable gas is collected in the second gas collector 25, and the second organic solution is collected in the second organic solution collection box 26.

[0105] (3) The primary oxidation degradation slurry was filtered and separated to obtain the first manganese-containing slag phase and the primary oxidation degradation liquid. The COD concentration in the primary oxidation degradation liquid was reduced to 6800 mg / L, the Mn concentration was 26 g / L, and the free H+ ion concentration was 0.5 g / L. The first manganese-containing slag phase was recovered for the preparation of silicon-based materials. The primary oxidation degradation liquid was subjected to an organic impurity-organic solvent dissolution and removal operation. First, toluene and N-methylpyrrolidone were mixed in a mass ratio of 2:1 to form an organic solvent. Then, it was placed in an aerosol (microbubble) generator with N2 as the medium to prepare an organic solvent aerosol (microbubble diameter of 0.1 to 10 μm) for selective dissolution of organic impurities. The prepared organic solvent aerosol (microbubble) was uniformly fed into the primary oxidation degradation liquid at a pressure of 0.9 MPa. Simultaneously, an ultrasonic wave with a frequency of 60 kHz and an ultrasonic wave intensity of 40 W / cm 2 Acting on the primary oxidation degradation liquid, the organic solvent aerosol (microbubble) enters the primary oxidation degradation liquid to quickly destabilize the organic impurities in the competitive solution, and the solvent aerosol (microbubble) and ultrasound are continuously pressed in, wherein the reaction temperature is 60°C, and the reaction is allowed to stand for 6 minutes, and the middle inorganic metal ion aqueous phase solution is separated to obtain a manganese sulfate solution layer, and the lower layer recovers the organic phase of hexane-pyrrolidone mixture and its dissolved impurities, and the upper layer recovers toluene and its dissolved impurities. The COD in the inorganic metal ion solution in the manganese-containing solution aqueous phase obtained by the treatment in this step is reduced to 1.0 g / L.

[0106] (4) The aqueous phase of the manganese-containing solution obtained in step (3) is mixed with the second manganese slag (same as the first manganese slag) and the second sulfuric acid solution with a mass concentration of 20% to form a slurry to be secondary oxidized (H + The concentration is 1.0 mol / L), and the slurry to be secondary oxidized is subjected to secondary oxidation degradation. The temperature is selected to be 80°C and the reaction time is 120 min to obtain a secondary oxidation degradation slurry; wherein the mass ratio of the manganese-containing solution aqueous phase to the second manganese slag is 3:1.

[0107] (5) filtering and secondary oxidation degradation of the slurry to obtain an inorganic metal ion solution and a second manganese-containing slag phase; wherein the inorganic metal ion solution contains Mn 2+ The concentration is 32 g / L and the COD is 0.24 g / L, which can be used for subsequent electrolysis or metal ion recovery; the second manganese-containing slag phase returns to step (2) and is mixed with the first manganese slag to be recovered and used as a manganese-containing oxidant.

[0108] Example 3

[0109] This embodiment provides a method for treating organic wastewater, which uses the system provided in Example 1 to treat wastewater, including the following steps:

[0110] (1) Take the high COD coking wastewater (COD concentration of 5.0×10 5mg / L, total ammonia concentration of 5000 mg / L, pH 7.2), the wastewater was placed in a low-temperature volatilization reactor for volatilization separation, and the temperature was raised to 90 °C for 60 min to obtain pretreated organic wastewater (COD concentration of 4.4×10 5 The volatile organic matter is introduced into a first condensation absorption tower 11 for condensation, absorption, collection and recovery of the volatilized volatile phenols to obtain a first non-condensable gas and a first organic solution. The first non-condensable gas is collected in a first gas collector 12, and the first organic solution is collected in a first organic solution collection box 13.

[0111] (2) Pretreated organic wastewater, high-grade first pyrolusite (Mn grade is 46.2%) and hydrochloric acid with a mass concentration of 15% are added to an oxidative degradation reactor 20 in a mass ratio of 5:1:1, and then stirred and leached at a temperature of 130° C. for 60 minutes to obtain a primary oxidative degradation slurry and oxidized volatiles. The oxidized volatiles are discharged from the oxidative degradation reactor 20 into a second condensation absorption tower 24 for condensation absorption to obtain a second non-condensable gas and a second organic solution. The second non-condensable gas is collected in a second gas collector 25, and the second organic solution is collected in a second organic solution collection box 26.

[0112] (3) The primary oxidation degradation slurry was filtered and separated to obtain a first manganese-containing slag phase and a primary oxidation degradation feed liquid. The COD concentration in the primary oxidation degradation feed liquid was reduced to 1900 mg / L, the Mn concentration was 96 g / L, and the free H + The ion concentration is 0.1 g / L; the first manganese-containing slag phase is recovered for the preparation of silicon-based materials. The organic impurities-organic solvent dissolution and removal operation is carried out on the primary oxidation degradation liquid. Carbon tetrachloride: n-hexyl ether: pyrrolidone are mixed in a mass ratio of 1:1:2 to form an organic solvent, and then it is placed in an aerosol (microbubble) generator with CO 2 The organic solvent aerosol (microbubble) is prepared as a medium, and the prepared organic solvent aerosol (microbubble) is uniformly fed into the primary oxidation degradation liquid at a pressure of 0.5 MPa. Simultaneously, the solution pressure is kept at 0.05 MPa during selective dissolution and separation by means of exhaustion, so that it reacts with organic impurities in the manganese sulfate solution. The solvent aerosol is continuously pressed in, the reaction temperature is controlled at 30°C, and the reaction is allowed to stand for 4 minutes to separate the middle aqueous phase to obtain a manganese-containing solution aqueous phase with impurities removed, the carbon tetrachloride-pyrrolidone mixture and its dissolved impurities are recovered in the lower layer, and the hexyl ether and its dissolved impurities are recovered in the upper layer.

[0113] (4) subjecting the inorganic metal ion solution to secondary oxidation degradation of manganese oxide, mixing the aqueous phase of the manganese-containing solution with a second pyrolusite (same as the first pyrolusite) and a second sulfuric acid solution with a mass concentration of 20% to form a slurry to be secondary oxidized (H +The concentration is 0.5 mol / L), and the slurry to be secondary oxidized is subjected to secondary oxidation degradation. The degradation temperature is selected to be 60° C. and the reaction time is 30 min to obtain a secondary oxidation degradation slurry; wherein the mass ratio of the manganese-containing solution aqueous phase to the second pyrolusite is 6:1.

[0114] (5) filtering and secondary oxidation degradation of the slurry to obtain an inorganic metal ion solution and a second manganese-containing slag phase; wherein the inorganic metal ion solution contains Mn 2+ The concentration is 96g / / L, and the COD is 0.2g / L, which can be used for electrolytic preparation of electrolytic manganese; the second manganese-containing slag phase returns to step (2) and is mixed with the first manganese-containing oxidant to be recycled as the manganese-containing oxidant.

[0115] Comparative Example 1

[0116] The difference between this comparative example and Example 2 is that in step (3), after filtering and separating the primary oxidative degradation liquid, the primary oxidative degradation liquid is directly subjected to steps (4) and (5), and the inorganic metal ion solution obtained has Mn 2+ The concentration is 26g / / L and the COD is 6.8g / L.

[0117] Comparative Example 2

[0118] The difference between this comparative example and Example 2 is that in step (3), a mixed solution of toluene and N-methylpyrrolidone (mass ratio 2:1) is used to replace the organic solvent aerosol and mix with the primary oxidation degradation liquid for selective dissolution and separation. In the inorganic metal ion solution obtained in step (5), Mn 2+ The concentration is 27g / / L and the COD is 5.2g / L.

[0119] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0120] The organic wastewater treatment method provided in the present application sequentially performs low-temperature volatilization, primary oxidation degradation, selective dissolution separation, secondary oxidation degradation and solid-liquid separation on the organic wastewater to be treated. Not only is the process simple, the wastewater treatment efficiency is high and it is not affected by wastewater quality and output fluctuations, but it can also remove highly polar and difficult-to-oxidize organic impurities to obtain an inorganic metal ion solution, and at the same time it can also recover volatile organic matter and oxidized volatiles, thereby realizing the added value of the chemical energy of the organic wastewater.

[0121] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An organic wastewater treatment system, It is characterized in that The organic wastewater treatment system comprises: A low-temperature volatilization unit, the low-temperature volatilization unit comprising a low-temperature volatilization reactor (10), the low-temperature volatilization reactor (10) being used to volatilize the organic wastewater to be treated at low temperature to obtain volatile organic matter and pretreated organic wastewater; A primary oxidation degradation unit, the primary oxidation degradation unit comprising an oxidation degradation reactor (20), the oxidation degradation reactor (20) being used to perform primary oxidation degradation on a slurry to be oxidized formed by mixing the pretreated organic wastewater with a first manganese-containing oxidant and a first dilute acid, to obtain a primary oxidation degradation slurry and oxidized volatiles; A dissolution and separation unit, the dissolution and separation unit comprising a first solid-liquid separator (38) and a dissolution and separation device (30), the first solid-liquid separator (38) being connected to the oxidative degradation reactor (20) and used for performing solid-liquid separation on the primary oxidative degradation slurry to obtain a primary oxidative degradation liquid and a first manganese-containing slag phase; the dissolution and separation device (30) being connected to the first solid-liquid separator (38) and used for mixing the primary oxidative degradation liquid with an organic solvent aerosol to perform a selective dissolution reaction and separate an aqueous phase from an organic phase to obtain an organic phase dissolving organic impurities and an aqueous phase containing a manganese solution; A secondary oxidation degradation unit, the secondary oxidation degradation unit comprising a secondary oxidation reactor (40), the secondary oxidation reactor (40) being used to perform secondary oxidation degradation on a solution to be secondary oxidized which is a mixture of the aqueous phase of the manganese-containing solution, a second manganese-containing oxidant and a second dilute acid, to obtain a secondary oxidation degradation slurry; A solid-liquid separation unit, wherein the solid-liquid separation unit comprises a second solid-liquid separator (50), wherein the second solid-liquid separator (50) is connected to the secondary oxidation reactor (40) and is used for performing solid-liquid separation on the secondary oxidation degradation slurry to obtain a second manganese-containing slag phase and an inorganic metal ion solution.

2. The organic wastewater treatment system according to claim 1, It is characterized in that The low-temperature volatilization unit further comprises a first condensation absorption tower (11), a first gas collector (12) and a first organic solution collection box (13); the first condensation absorption tower (11) is connected to the low-temperature volatilization reactor (10) and is used to condense the volatile organic matter to obtain a first non-condensable gas and a first organic solution; the first gas collector (12) is connected to the gas phase outlet of the first condensation absorption tower (11) and is used to collect the first non-condensable gas; the first organic solution collection box (13) is connected to the liquid phase outlet of the first condensation absorption tower (11) and is used to collect the first organic solution; And / or, the primary oxidation degradation unit further comprises a first manganese-containing oxidant feeding device (21), a first dilute acid feeding device (22), a slurry mixing device (23), a second condensation absorption tower (24), a second gas collector (25) and a second organic solution collecting box (26); the slurry mixing device (23) is arranged on the pipeline between the low-temperature volatilization reactor (10) and the oxidation degradation reactor (20), and is used to mix the pretreated organic wastewater with the first manganese-containing oxidant and the first dilute acid into the slurry to be oxidized once; the first manganese-containing oxidant feeding device (21) is connected to the slurry mixing device (23), and is used to feed the slurry to the slurry mixing device (23). The device (23) provides the first manganese-containing oxidant, and the first dilute acid supply device (22) is also connected to the slurry mixing device (23) for providing the first dilute acid to the slurry mixing device (23); the second condensation absorption tower (24) is connected to the oxidation degradation reactor (20) for condensing the oxidized volatiles to obtain a second non-condensable gas and a second organic solution; the second gas collector (25) is connected to the gas phase outlet of the second condensation absorption tower (24) for collecting the second non-condensable gas; the second organic solution collection box (26) is connected to the liquid phase outlet of the second condensation absorption tower (24) for collecting the second organic solution.

3. The organic wastewater treatment system according to claim 1 or 2, It is characterized in that The dissolution and separation unit further comprises a bubble explosion assistant (31), an aerosol generator (32), an air supply device (33), an organic solvent mixer (34), an organic solvent distillation device (35), a third organic solution collection box (36) and a fourth organic solution collection box (37); The aerosol generator (32) is connected to the dissolution and separation device (30) and is used to provide the organic solvent aerosol to the dissolution and separation device (30); the gas supply device (33) is connected to the aerosol generator (32) and is used to provide gas to the aerosol generator (32); the organic solvent mixer (34) is also connected to the aerosol generator (32) and is used to provide the organic solvent to the aerosol generator (32); the bubble explosion assistant (31) is arranged on the dissolution and separation device (30) and is used to explode the organic solvent aerosol in the dissolution and separation device (30); The organic solvent distillation device (35) is connected to the dissolution separation device (30) and is used to distill the organic phase containing the dissolved organic impurities to obtain a distillation solvent and a residual liquid. The third organic solution collection box (36) is connected to the gas phase outlet of the organic solvent distillation device (35) and is used to collect the distillation solvent. The fourth organic solution collection box (37) is connected to the liquid phase outlet of the organic solvent distillation device (35) and is used to collect the residual liquid. The dissolution separation unit further comprises a first slag phase collecting box (39), wherein the first slag phase collecting box (39) is connected to the first solid-liquid separator (38) and is used for collecting the first manganese-containing slag phase.

4. The organic wastewater treatment system according to claim 1 or 2, It is characterized in that The secondary oxidation degradation unit further comprises a second manganese-containing oxidant feeding device (41) and a second dilute acid feeding device (42); the second manganese-containing oxidant feeding device (41) is connected to the secondary oxidation reactor (40) for providing the second manganese-containing oxidant to the secondary oxidation reactor (40), and the second dilute acid feeding device (42) is also connected to the secondary oxidation reactor (40) for providing the second dilute acid to the secondary oxidation reactor (40).

5. The organic wastewater treatment system according to claim 1 or 2, It is characterized in that In the solid-liquid separation unit, the second solid-liquid separator (50) is also connected to the oxidative degradation reactor (20) to return the second manganese-containing slag phase to the oxidative degradation reactor (20); The solid-liquid separation unit further comprises a second slag phase collecting box (51) and an inorganic metal ion solution collecting box (52), wherein the second slag phase collecting box (51) is connected to the second solid-liquid separator (50) and is used to collect the second manganese-containing slag phase, and the inorganic metal ion solution collecting box (52) is also connected to the second solid-liquid separator (50) and is used to collect the inorganic metal ion solution.

6. A method for treating organic wastewater, It is characterized in that The method for treating organic wastewater comprises: Step S1, volatilizing the organic wastewater to be treated at low temperature to obtain volatile organic matter and pretreated organic wastewater; Step S2, subjecting the pretreated organic wastewater, the first manganese-containing oxidant and the first dilute acid to a mixture to form a slurry to be oxidized, to primary oxidation degradation, to obtain a primary oxidation degradation slurry and oxidized volatiles; Step S3, performing solid-liquid separation on the primary oxidative degradation slurry to obtain a first manganese-containing slag phase and a primary oxidative degradation feed liquid, mixing the primary oxidative degradation feed liquid with an organic solvent aerosol to perform a selective dissolution reaction and performing separation of an aqueous phase and an organic phase to obtain an organic phase dissolving organic impurities and an aqueous phase containing a manganese solution; Step S4, subjecting the aqueous phase of the manganese-containing solution to a mixture of a second manganese-containing oxidant and a second dilute acid to obtain a secondary oxidation degradation slurry, to secondary oxidation degradation slurry; Step S5, performing solid-liquid separation on the secondary oxidation degradation slurry to obtain a second manganese-containing slag phase and an inorganic metal ion solution.

7. The method for treating organic wastewater according to claim 6, It is characterized in that In the step S1, the temperature of the low-temperature volatilization is 60 to 95° C. and the time is 20 to 30 minutes.

8. The method for treating organic wastewater according to claim 7, It is characterized in that The step S1 further comprises condensing and absorbing the volatile organic matter to obtain a first non-condensable gas and a first organic solution; And / or, in step S2, the temperature of the primary oxidation degradation is 70-250° C. and the time is 10-360 min.

9. The method for treating organic wastewater according to claim 8, It is characterized in that The H + The concentration is 0.5~3mol / L; The mass ratio of the first manganese-containing oxidant to the pretreated organic wastewater is 1:(2-10); The step S2 further comprises condensing and absorbing the oxidized volatiles to obtain a second non-condensable gas and a second organic solution.

10. The method for treating organic wastewater according to claim 6, It is characterized in that In step S3, the organic solvent aerosol is a microbubble organic solvent aerosol, the diameter of the microbubble is 0.001-100 μm, and the gas in the organic solvent aerosol includes CO 2 、N 2 or at least one of an inert gas.

11. The method for treating organic wastewater according to claim 10, It is characterized in that The organic solvent aerosol is prepared by passing an organic solvent through an aerosol generator (32); the organic solvent is a weakly polar organic solvent and / or a non-polar organic solvent, and is insoluble in water or slightly soluble in water.

12. The method for treating organic wastewater according to claim 11, It is characterized in that The weakly polar organic solvent includes at least one of an ether compound or an alkane compound; the non-polar organic solvent includes at least one of carbon tetrachloride, carbon disulfide, an alkane compound, kerosene, benzene and its non-polar derivatives; The organic solvent aerosol is pressed into the primary oxidation degradation liquid at a pressure of 0.12-0.6 MPa for mixing; The selective dissolution reaction is carried out at a temperature of -10 to 90°C, a time of 0.5 to 20 minutes, and a pressure of 0.01 to 0.09 MPa; The selective dissolution reaction is carried out under the action of ultrasound, the ultrasound frequency is 20kHz to 60kHz, and the intensity is 20 to 80W / cm 2 ; In the primary oxidation degradation liquid, COD cr The content is 0.5~10g / L, Mn 2+ Content is 2.0~120g / L; The step S3 further comprises distilling the organic phase containing dissolved organic impurities to obtain a distillation solvent and a raffinate.

13. The method for treating organic wastewater according to claim 6, It is characterized in that In the step S4, the temperature of the secondary oxidation degradation is 60-90° C., and the reaction time is 20-30 min.

14. The method for treating organic wastewater according to claim 13, It is characterized in that The mass ratio of the second manganese-containing oxidant to the aqueous phase of the manganese-containing solution is 1:(2-10); The H + The concentration is 0.5~3mol / L.

15. The method for treating organic wastewater according to any one of claims 6 to 14, It is characterized in that In the step S5, the second manganese-containing slag phase returns to the step S2 and is mixed with the first manganese-containing oxidant.

16. The method for treating organic wastewater according to claim 15, It is characterized in that The COD in the organic wastewater to be treated cr ≥5 g / L; The particle sizes of the first manganese-containing oxidant and the second manganese-containing oxidant are each independently ≤0.15 mm, and the first manganese-containing oxidant and the second manganese-containing oxidant are each independently selected from pyrolusite, manganese nodules or MnO-containing 2 at least one of the waste materials; The first dilute acid and the second dilute acid are each independently selected from at least one of sulfuric acid, hydrochloric acid, nitric acid or industrial waste acid.

17. The method for treating organic wastewater according to claim 16, It is characterized in that The first dilute acid and the second dilute acid are sulfuric acid.

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