Zero-discharge treatment process for high-salt organic wastewater of hazardous waste treatment plant

Abstract

The invention discloses a hazardous waste treatment plant high-salt organic wastewater zero-discharge treatment device, and relates to the technical field of high-salt organic wastewater treatment, the hazardous waste treatment plant high-salt organic wastewater zero-discharge treatment device comprises a chemical hardness removal device for reducing wastewater hardness, and a water outlet of the chemical hardness removal device is communicated with an MVR evaporative crystallization device. When the device is used, the hardness of the high-salinity wastewater is firstly improved through the arranged chemical hardness removal device, and then the salt in the water is evaporated, concentrated, crystallized and separated through the MVR evaporative crystallization device, so that solid carnallite is formed and discharged out of the water body; distilled water generated by evaporation is deeply desalted through the integrated biological sewage treatment device and the membrane treatment device, so that the wastewater can reach the factory recycling standard, and the purified wastewater can be recycled in a production process, thereby achieving the purpose of zero-discharge treatment of high-salt and high-organic wastewater in a hazardous waste treatment plant. The leakage of the wastewater in the process of being discharged towards a municipal sewage treatment plant is effectively avoided, and the ecological environment is ensured not to be polluted by the high-salinity wastewater.

Description

Technical Field

[0001] The invention relates to the technical field of industrial wastewater treatment, and in particular to a zero-discharge treatment process for high-salt organic wastewater from a hazardous waste treatment plant. Background Art

[0002] The hazardous waste categories in the "National List of Hazardous Wastes" include medical waste, waste drugs, medicines, pesticide waste, waste mineral oil, oil / water, hydrocarbon / water, distillation residues, dye and paint waste, organic resin waste, surface treatment waste, copper-containing waste, organic halide waste, nickel-containing waste, organic solvent waste, waste acid, waste alkali, and other wastes.

[0003] Hazardous waste treatment plants use different disposal processes for different waste types, such as: Industrial sludge: collection - storage - drum drying and reduction - transportation; Organic silicon residue: collection - storage - standing - recovery of silicone oil - leaching - filtration - extraction - electrolysis - metal products, filter residue - recovery of silicon powder and carbon powder - drying - external transportation; Scrap iron barrels: collection - cleaning - sandblasting - painting - recycling iron barrels or collection - cutting - soaking and washing - melting and casting - iron blocks for sale; Waste plastics: collection - cutting - cleaning - melting - recycling and granulation - sale.

[0004] In the process of treating hazardous waste, hazardous waste treatment plants will produce high-salt, high-organic wastewater containing a large amount of heavy metal ions, which is difficult to treat. If it is discharged directly, it will cause serious pollution to the environment and water bodies. At present, most hazardous waste treatment wastewater is treated by simple coagulation and sedimentation and then discharged to municipal sewage treatment plants. This method has certain problems and may cause new pollution. Summary of the invention

[0005] The purpose of the present invention is to provide a zero-discharge treatment process for high-salt organic wastewater in a hazardous waste treatment plant to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a zero-discharge treatment process for high-salt organic wastewater in a hazardous waste treatment plant, wherein the high-salt organic wastewater is first discharged into a sewage regulating tank, and the wastewater in the sewage regulating tank is lifted to a chemical de-hardening device. After the chemical de-hardening device softens the wastewater, the generated chemical sludge is discharged to a sludge treatment device, dehydrated and transported to a hazardous waste treatment plant for treatment, the sludge filtered water is returned to the sewage regulating tank, the effluent from the chemical de-hardening device enters distillation, the generated solid salts are sent to the hazardous waste treatment plant, the distillation generated is cooled and sent to an integrated sewage biological treatment device, the COD is reduced by biochemical treatment, the effluent from the integrated sewage biological treatment device enters a membrane treatment device, the reverse osmosis desalted water produced by the membrane treatment device is sent to the hazardous waste treatment plant workshop for reuse as process water, and the reverse osmosis concentrate is returned to the sewage regulating tank so as to re-enter the system for the next round of treatment.

[0007] Furthermore, the chemical hardness removal device includes a caustic soda dosing device, a soda ash dosing device, a coagulant dosing device, a coagulant dosing device and a heavy metal capture agent dosing device for adding caustic soda, soda ash, coagulant, coagulant aid and heavy metal capture agent to the sequencing batch reaction precipitator respectively; and also includes an acid adding device for adding acidic agents to further reduce the hardness of water.

[0008] Furthermore, the hardened water softened by the chemical de-hardening device from the high-salt organic wastewater is evaporated, condensed and centrifuged in the MVR evaporation crystallization device to remove solid salts.

[0009] Furthermore, the integrated sewage biological treatment device includes an inlet tank, an anoxic tank, an aerobic tank, a secondary sedimentation tank, an inclined tube sedimentation tank, and a clear water tank; the sewage treated by the MVR evaporation crystallization device enters the inlet tank, and is lifted to the anoxic tank and the aerobic tank by a biochemical lift pump. The anoxic tank and the aerobic tank adopt a biological contact oxidation method, and the filler adopts a hanging filler. The sewage is fully in contact with the biofilm on the surface of the filler, and the COD and ammonia nitrogen in the sewage are removed by biodegradation. An aeration device is set at the bottom of the aerobic tank. According to the water quality requirements of the inlet / product water, a carbon source and an alkali are added to the anoxic tank and the aerobic tank respectively through a carbon source adding device and an alkali adding device. The nitrification liquid reflux pump is started during operation. Part of the sewage from the aerobic tank is circulated to the anoxic tank to increase the removal rates of total nitrogen and COD. At the same time, coagulant is added to the secondary sedimentation tank through the coagulant dosing equipment to accelerate the sedimentation process; the effluent from the aerobic tank flows by gravity into the secondary sedimentation tank, and the secondary sedimentation tank adopts a vertical flow sedimentation tank. The effluent from the secondary sedimentation tank flows by gravity into the inclined tube sedimentation tank, and the effluent from the inclined tube sedimentation tank flows by gravity into the clear water tank. Coagulant is added at the water inlet of the secondary sedimentation tank to improve the sedimentation effect. The secondary sedimentation tank and the inclined tube sedimentation tank discharge the biochemical sludge to the sludge thickening tank at regular intervals, and the supernatant of the sludge thickening tank is discharged to the supernatant tank, which is lifted to the inlet tank by the supernatant pump for recycling. The concentrated biochemical sludge at the bottom of the sludge thickening tank is pumped to the sludge treatment device by the sludge thickening pump.

[0010] Furthermore, the sewage treated by the integrated sewage biological treatment device enters the membrane treatment device to remove suspended matter, colloids, microorganisms and bacteria in the water through filtration.

[0011] In summary, the technical effects and advantages of the present invention are as follows: In the present invention, the hardness of the high-salt wastewater is firstly measured by the chemical hardness removal device, and then the MVR evaporation and crystallization device is used to evaporate, concentrate, crystallize and separate the salt in the water to form solid impurities and discharge the water body. The distilled water generated by evaporation is then deeply desalted by the integrated sewage biological treatment device and the membrane treatment device to meet the plant reuse standard, so that the purified wastewater can be reused in the production process, thereby achieving the purpose of zero-discharge treatment of high-salt and high-organic wastewater in hazardous waste treatment plants, effectively avoiding leakage of wastewater during discharge to municipal sewage treatment plants, and ensuring that the ecological environment is not polluted by high-salt wastewater.

[0012] In the present invention, a membrane treatment device is set up, and the membrane treatment device includes a pre-filtration device. The pre-filtration device can effectively remove suspended matter, colloids, microorganisms, bacteria, etc. in water, thereby protecting the reverse osmosis membrane from being impacted by larger particulate impurities during the filtration process, extending the service life of the reverse osmosis membrane, and improving the reliability and practicality of the treatment device. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 This is a schematic diagram of the overall structure of a zero-discharge treatment device for high-salt organic wastewater in a hazardous waste treatment plant according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a chemical hardness removal device in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an MVR evaporation crystallization device in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an integrated sewage biological treatment device in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a membrane treatment device in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a sludge treatment device in an embodiment of the present invention; Figure 7 This is a wastewater treatment process flow chart of a zero-discharge treatment device for high-salt organic wastewater in a hazardous waste treatment plant in an embodiment of the present invention.

[0015] In the figure: 1. Sewage regulating tank; 2. Chemical de-hardening device; 21. First lifting pump; 22. Sequential batch reactor precipitator; 23. De-hardening water tank; 241. Caustic soda dosing device; 242. Soda ash dosing device; 243. Heavy metal scavenger dosing device; 244. Coagulant dosing device; 245. Coagulant aid dosing device; 246. Acid dosing device; 3. MVR evaporation crystallization device; 31. First water inlet booster pump; 33. Forced circulation pump; 34. Forced circulation evaporator; 35. Separator; 351, discharge pump; 36, centrifuge; 37, primary preheater; 38, secondary preheater; 39, secondary steam compressor; 310, distilled water tank; 311, distilled water pump; 312, mother liquid tank; 313, mother liquid pump; 314, vacuum pump; 315, condenser; 4, integrated sewage biological treatment device; 41, cooler; 42, water inlet pool; 43, biochemical lifting pump; 44, anoxic pool; 45, aerobic pool; 451, nitrification liquid reflux pump; 452, fan; 46. ​​Secondary sedimentation tank; 47. Inclined tube sedimentation tank; 48. Clear water tank; 49. Sludge thickening tank; 410. Supernatant tank; 411. Sludge thickening pump; 412. Supernatant pump; 413. Carbon source adding device; 414. Alkali adding device; 415. Coagulant dosing equipment; 5. Membrane treatment device; 52. Ultrafiltration water production tank; 53. Reverse osmosis booster pump; 54. Security filter; 55. Reverse osmosis high-pressure pump; 56. Reverse osmosis circulation pump; 57. Reverse osmosis device; 58. Reverse osmosis water production tank; 581. Second water inlet booster pump; 582. Ultrafiltration backwash water pump; 59. Reverse osmosis water production pump; 5101. Reductant dosing device; 5102. Scale inhibitor dosing device; 5103. Non-oxidizing bactericide dosing device; 511. Quartz sand filter; 512. Bag filter; 513. Ultrafiltration device; 6. Sludge treatment device; 62. Sludge pump; 63. Plate and frame filter press; 64. Pressing water pump; 641. Pressing water tank; 65. Belt conveyor; 66. Dewatered sludge storage tank. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Please refer to Figure 1-Figure 7The shown device is a zero-discharge treatment device for high-salt organic wastewater in a hazardous waste treatment plant, comprising a chemical hardness removal device 2 for reducing the hardness of wastewater and a sludge treatment device 6, the water outlet of the chemical hardness removal device 2 is connected to an MVR evaporation crystallization device 3, the water outlet of the MVR evaporation crystallization device 3 is connected to an integrated sewage biological treatment device 4, the water outlet of the integrated sewage biological treatment device 4 is connected to a membrane treatment device 5, and the sludge discharge port of the chemical hardness removal device 2 and the sludge discharge port of the integrated sewage biological treatment device 4 are both connected to the sludge treatment device 6. When treating high-salt organic wastewater generated in the process of hazardous waste treatment, the device first discharges it to the sewage regulating tank 1 through a pipeline or a trench. The wastewater in the sewage regulating tank 1 is lifted by the first lifting pump 21 to the chemical de-hardening device 2. The chemical sludge generated by the chemical de-hardening device 2 is discharged to the sludge treatment device 6, and then transported to the hazardous waste treatment plant for treatment after dehydration. The sludge filtered water returns to the sewage regulating tank 1. The effluent of the chemical de-hardening device 2 enters the MVR evaporation crystallization device 3. The generated solid salt is sent to the hazardous waste treatment plant. The distilled water is cooled by the cooler 41 and sent to the integrated sewage biological treatment device 4. After biochemical treatment to reduce COD, the effluent of the integrated sewage biological treatment device 4 enters the membrane treatment device 5. The produced reverse osmosis desalted water is sent to the workshop of the hazardous waste treatment plant for reuse as process water. The reverse osmosis concentrated liquid returns to the sewage regulating tank 1 so as to re-enter the system for the next round of treatment. The whole process realizes zero discharge of wastewater in the process of hazardous waste treatment, and achieves the effects of environmental protection and energy saving.

[0018] refer to Figure 2The chemical hardness removal device 2 includes a first lifting pump 21, and the sewage is sucked into the first lifting pump 21 through the water inlet of the first lifting pump 21. The water outlet of the first lifting pump 21 is connected to the ordered batch reaction precipitator 22, and the water outlet of the sequencing batch reaction precipitator 22 is connected to the hardness removal water tank 23. The chemical hardness removal device 2 also includes a caustic soda dosing device 241, a soda ash dosing device 242, a coagulant dosing device 243, a coagulant dosing device 244 and a heavy metal capture agent dosing device 245 for adding caustic soda, soda ash, coagulant, coagulant aid, and heavy metal capture agent to the sequencing batch reaction precipitator 22 respectively. These agents can effectively remove hardness substances such as calcium and magnesium in the water to soften the water quality; the chemical hardness removal device 2 also includes an acid adding device 246, which can further reduce the hardness of the water by adding acidic agents. Such a design can not only effectively remove hardness substances in the water, but also prevent the subsequent sewage treatment process from having excessive water hardness again, thereby improving the efficiency and stability of the entire treatment system. The outlet of the acid adding device 246 is connected to the outlet pipe of the sequencing batch reactor precipitator 22. In this device, the high-salt organic wastewater generated in the hazardous waste treatment process is discharged to the sewage regulating tank 1 through a pipeline or a ditch, and is lifted to the sequencing batch reactor precipitator 22 by the first lifting pump 21. During the water intake process, the caustic soda dosing device 241, the soda ash dosing device 242, the heavy metal scavenger dosing device 243, the coagulant dosing device 244, and the coagulant aid dosing device 245 are started, and caustic soda, soda ash, heavy metal scavenger, coagulant, coagulant aid and other agents are added respectively, and the mixer is started for sufficient reaction. The sequencing batch reactor precipitator After the precipitator 22 is full of liquid, stop the first lifting pump 21 and the metering pumps of each dosing device, continue stirring and reacting for 15 to 30 minutes, stop the agitator, let it settle for 30 to 60 minutes, open the outlet valve, and start the acid adding device 246 to discharge the hardened clean water to the hardened water tank 23, control the amount of acid added to maintain the pH at 7 to 7.5, and after the drainage is completed, close the outlet valve, stop the acid adding metering pump, and then open the bottom sludge valve of the sequencing batch reactor precipitator 22 to discharge the chemical sludge to the sludge tank of the sludge treatment device 6. Through the above series of treatment steps, the hardness substances in the wastewater can be effectively removed, and deep treatment can also be performed to achieve the effect of softening the water quality.

[0019] refer to Figure 3, an MVR evaporation crystallization device 3, wherein the MVR evaporation crystallization device 3 comprises a first water inlet booster pump 31, wherein the water inlet of the first water inlet booster pump 31 is connected to the water outlet of the hard water removal tank 23, wherein the water outlet of the first water inlet booster pump 31 is connected to a preheating device, wherein the water outlet of the preheating device is connected to a forced circulation pump 33 for pressurizing the wastewater, wherein the water outlet of the forced circulation pump 33 is connected to a forced circulation evaporator 34, wherein the discharge port of the forced circulation evaporator 34 is connected to a separator 35, wherein the water outlet of the separator 35 is connected to a centrifuge 36, wherein the salt component in the wastewater discharged from the separator 35 is separated by the centrifugal operation of the centrifuge 36, and the water outlet of the centrifuge 36 is used to discharge the wastewater remaining after the centrifugal separation; The preheating device includes a primary preheater 37 and a secondary preheater 38, the water inlet of the primary preheater 37 is connected to the water inlet of the first water inlet booster pump 31, the water outlet of the primary preheater 37 is connected to the water inlet of the secondary preheater 38, the water outlet of the secondary preheater 38 is connected to the water inlet of the forced circulation pump 33, the heat medium of the primary preheater 37 is distilled water, the heat medium of the secondary preheater 38 is low-pressure saturated steam, the steam inlet of the secondary preheater 38 is connected to the external steam pipe, the steam outlet of the separator 35 is connected to the secondary steam compressor 39, the steam outlet of the secondary steam compressor 39 is connected to the steam inlet of the forced circulation evaporator 34, and the secondary steam compressed by the secondary steam compressor 39 enters the forced circulation evaporator 34 as a heat medium; The preheating device also includes a distilled water tank 310. The distilled water formed after steam heat exchange in the primary preheater 37 and the distilled water formed by condensation after secondary steam heat exchange in the forced circulation evaporator 34 are both transported to the distilled water tank 310 through the water outlet. The water inlet of the distilled water tank 310 is connected to a distilled water pump 311, and the distilled water pump 311 can pressurize the distilled water. The water outlet of the distilled water pump 311 is connected to the heat medium feed port of the primary preheater 37.

[0020] The MVR evaporation crystallization device 3 also includes a mother liquid tank 312, the water inlet of the mother liquid tank 312 is connected to the water outlet of the centrifuge 36, the water outlet of the mother liquid tank 312 is connected to a mother liquid pump 313, the water outlet of the mother liquid pump 313 is connected to the feed port of the separator 35, and the mother liquid pump 313 can pressurize the mother liquid discharged from the centrifuge 36.

[0021] In the device, the de-hardened water enters the primary preheater 37 after being pressurized. The primary preheater 37 adopts a plate heat exchanger. The heat medium of the primary preheater 37 adopts distilled water. The de-hardened water enters the secondary preheater 38 after passing through the primary preheater 37. The secondary preheater 38 adopts a shell and tube heat exchanger. The heat medium of the secondary preheater 38 adopts low-pressure saturated steam. The steam inlet is connected to the external steam pipe. The steam is liquefied into distilled water after heat exchange and discharged to the distilled water tank 310. The outlet water of the secondary preheater 38 and the outlet water of part of the separator 35 enter the inlet pipe of the forced circulation pump 33 together, and enter the forced circulation evaporator 34 after being pressurized. The forced circulation evaporator 34 adopts a shell and tube heat exchanger. The heat medium of the forced circulation evaporator 34 adopts secondary steam compressed by the secondary steam compressor 39 to increase the thermal enthalpy. The water after heat exchange in the forced circulation evaporator 34 reaches the boiling point and enters the separator 35. The secondary steam is discharged from the separator 35, and the aqueous solution is concentrated. The secondary steam is connected to the inlet of the secondary steam compressor 39. During the operation of the forced circulation evaporator 34, the vacuum pump 314 is continuously operated to keep the evaporation device in a negative pressure state to reduce the boiling point of the aqueous solution. A condenser 315 is arranged at the inlet pipe of the vacuum pump 314. The condenser 315 adopts a shell and tube heat exchanger, and the cold medium adopts the circulating cooling water of the plant area, so that the small amount of steam extracted is cooled into condensed water. After the concentration of the aqueous solution in the separator 35 reaches an oversaturated state, it is discharged to the centrifuge 36 by the discharge pump 351. The solid salt produced by the centrifuge 36 is collected and sent to a hazardous waste treatment plant for treatment. The mother liquor discharged from the centrifuge 36 enters the mother liquor tank 312, and is pressurized by the mother liquor pump 313 and returns to the separator 35. The compressed secondary steam is liquefied into distilled water after heat exchange in the forced circulation evaporator 34, and is discharged to the distilled water tank 310. It is pressurized by the distilled water pump 311 and enters the primary preheater 37. After heat exchange, it is discharged from the evaporation device and enters the cooler 41 and the water inlet pool 42 of the integrated sewage biological treatment device 4.

[0022] Through the above treatment, salt and other solid impurities in the wastewater can be effectively separated.

[0023] refer to Figure 4, an integrated sewage biological treatment device 4, the integrated sewage biological treatment device 4 includes a cooler 41, the water inlet of the cooler 41 is connected to the water outlet of the forced circulation evaporator 34, the water outlet of the cooler 41 is connected to an inlet pool 42, a biochemical lift pump 43 is arranged in the inlet pool 42, the water outlet of the biochemical lift pump 43 is connected to an anoxic pool 44, the integrated sewage biological treatment device 4 also includes an aerobic pool 45, the wastewater in the anoxic pool 44 is sent to the aerobic pool 45 by the biochemical lift pump 43 arranged in the anoxic pool 44, the aerobic pool 45 It is connected to a secondary sedimentation tank 46, and the secondary sedimentation tank 46 is connected to an inclined tube sedimentation tank 47. The outlet of the inclined tube sedimentation tank 47 is connected to a clean water tank 48. The mud discharge port of the inclined tube sedimentation tank 47 is connected to a sludge thickening tank 49. The supernatant outlet of the sludge thickening tank 49 is connected to a supernatant tank 410. A supernatant pump 412 is provided in the supernatant tank 410. The outlet of the supernatant pump 412 is connected to the water inlet tank 42. A sludge thickening pump 411 is installed at the bottom of the sludge thickening tank 49, and the mud outlet of the sludge thickening pump 411 is connected to the sludge treatment device 6. In the device, the distilled water produced by the MVR evaporation crystallization device 3 enters the cooler 41. The cooler 41 adopts an air-cooled cooler 41. After the cold air enters the cooler 41 for heat exchange, the temperature rises to become hot air and is discharged to the atmosphere. The distilled water cooled by the cooler 41 enters the water inlet pool 42 and is lifted to the anoxic pool 44 and the aerobic pool 45 by the biochemical lifting pump 43. The anoxic pool 44 and the aerobic pool 45 adopt the biological contact oxidation method, and the filler adopts the hanging filler. The sewage is fully in contact with the biofilm on the surface of the filler, and the wastewater is removed by biodegradation. To remove COD, ammonia nitrogen, etc. in sewage, an aeration device is provided at the bottom of the aerobic tank 45, and aeration and oxygenation are performed by a fan 452. According to the quality requirements of the influent / product water, a carbon source and an alkali are added to the anoxic tank 44 and the aerobic tank 45 respectively through a carbon source adding device 413 and an alkali adding device 414. During operation, a nitrification liquid reflux pump 451 is started to circulate part of the sewage from the aerobic tank 45 to the anoxic tank 44 to improve the removal rate of total nitrogen and COD. At the same time, a coagulant is added to the secondary sedimentation tank 46 through a coagulant dosing device 415 to accelerate the sedimentation process; The effluent from the aerobic tank 45 flows by gravity into the secondary sedimentation tank 46. The secondary sedimentation tank 46 adopts a vertical flow sedimentation tank. The effluent from the secondary sedimentation tank 46 flows by gravity into the inclined tube sedimentation tank 47. The effluent from the inclined tube sedimentation tank 47 flows by gravity into the clean water tank 48. Coagulant is added at the water inlet of the secondary sedimentation tank 46 to improve the sedimentation effect. The secondary sedimentation tank 46 and the inclined tube sedimentation tank 47 discharge the biochemical sludge to the sludge thickening tank 49 at a regular interval. The supernatant of the sludge thickening tank 49 is discharged to the supernatant tank 410, which is lifted to the water inlet tank 42 by the supernatant pump 412 for recycling. The concentrated biochemical sludge at the bottom of the sludge thickening tank 49 is sent to the sludge treatment device 6 by the sludge thickening pump 411.

[0024] refer to Figure 5The membrane treatment device 5 includes a pre-filtering device, the water inlet of the pre-filtering device is connected to the clean water tank 48, the pre-filtering device is used to remove impurities such as suspended matter, colloids, microorganisms, bacteria, etc. in the wastewater, the water outlet of the pre-filtering device is connected to an ultrafiltration water production tank 52, the ultrafiltration water production tank 52 is connected to a reverse osmosis booster pump 53, the reverse osmosis booster pump 53 is connected to a security filter 54, the water outlet of the security filter 54 is connected to a reverse osmosis high-pressure pump 55, the water outlet of the reverse osmosis high-pressure pump 55 is connected to a reverse osmosis circulation pump 56, the reverse osmosis circulation pump 56 is connected to a reverse osmosis device 57, the water outlet of the reverse osmosis device 57 is connected to a reverse osmosis water production tank 58, the reverse osmosis water production tank 58 is provided with a reverse osmosis water production pump 59, the water outlet of the reverse osmosis water production pump 59 is connected to the plant area reuse water point, and the concentrated liquid water outlet of the reverse osmosis device 57 is connected to the sewage regulating tank 1; The membrane treatment device 5 further comprises a reducing agent dosing device 5101 , an antiscalant dosing device 5102 and a non-oxidizing bactericide dosing device 5103 which are connected to the inlet pipe of the safety filter 54 .

[0025] The inlet of the second water inlet booster pump 581 is connected to the outlet of the clear water tank 48 of the integrated sewage biological treatment device 4, and the water is pressurized to enter the quartz sand filter 511, the bag filter 512, and the ultrafiltration device 513. The ultrafiltration membrane has a filtration accuracy of 30nm, which can effectively remove suspended matter, colloids, microorganisms, bacteria, etc. in the water and protect the reverse osmosis membrane. The quartz sand filter 511 and the bag filter 512 are used to filter large particles of suspended matter and colloids in the water and protect the ultrafiltration membrane. The water produced by the ultrafiltration device 513 enters the ultrafiltration water production tank 52, and after being pressurized by the reverse osmosis booster pump 53, it enters the security filter 54, the reverse osmosis high-pressure pump 55, the reverse osmosis circulation pump 56, and the reverse osmosis device 57. The reverse osmosis product water enters the reverse osmosis water production tank 58 and is sent to the water reuse point in the plant area by the reverse osmosis water production pump 59; The reverse osmosis concentrated liquid is returned to the sewage regulating tank 1. During the operation of the reverse osmosis device 57, the reducing agent dosing device 5101, the antiscalant dosing device 5102, and the non-oxidizing bactericide dosing device 5103 are started to add relevant agents; The quartz sand filter 511 and the ultrafiltration device 513 need to be backwashed regularly by the ultrafiltration backwash water pump 582, and the reverse osmosis device 57 needs to be low-pressure flushed when starting / stopping. The backwash and flushing wastewater is discharged into the sludge concentration tank 49 of the integrated sewage biological treatment device 4 through the ditch.

[0026] refer to Figure 6The sludge treatment device 6 includes a sludge pool, in which a sludge pump 62 is provided, the sludge outlet of the sludge pump 62 is connected to a plate and frame filter press 63, the water outlet of the plate and frame filter press 63 is connected to a squeeze water pump 64, the water outlet of the squeeze water pump 64 is connected to a squeeze water tank 641, the dehydrated sludge outlet of the plate and frame filter press 63 is connected to a belt conveyor 65, and the belt conveyor 65 is connected to a dehydrated sludge storage tank 66. The sludge pool receives the chemical sludge discharged from the sequencing batch reaction precipitator 22 of the chemical hardness removal device 2 and the concentrated biochemical sludge discharged from the sludge thickening tank 49 of the integrated sewage biological treatment device 4, which are pressurized by the sludge pump 62 and sent to the plate and frame filter press 63. The sludge is dehydrated and dried to become a mud cake with a moisture content of less than 70%. It is unloaded to the dehydrated sludge storage box 66 through the belt conveyor 65 and transported to the hazardous waste treatment plant. The filtered water of the plate and frame filter press 63 is discharged to the sewage regulating tank 1 for recovery. The pressing adopts water pressing and is recycled through the pressing water tank 641 and the pressing water pump 64.

[0027] Processing process: The high-salt organic wastewater generated during the hazardous waste treatment process is discharged to the sewage regulating tank 1 through a pipeline or a ditch, and is lifted to the sequencing batch reactor precipitator 22 by the first lifting pump 21. During the water intake process, caustic soda, soda ash, heavy metal capture agent, coagulant, coagulant aid and other agents are added, and the mixer is started for full reaction. After the sequencing batch reactor precipitator 22 is full of liquid, the first lifting pump 21 and each dosing metering pump are stopped. After the stirring reaction is continued for 15 to 30 minutes, the mixer is stopped, and the precipitation is allowed to stand for 30 to 60 minutes. The outlet valve is opened, and the acid adding device 246 is started to discharge the clean water after hardness removal to the hardness removal water tank. The amount of acid added is controlled to maintain the pH at 7 to 7.5. After the drainage is completed, the outlet valve is closed and the acid adding device 246 is stopped; then the mud discharge valve at the bottom of the sequencing batch reactor precipitator 22 is opened to discharge the chemical sludge to the sludge tank of the sludge treatment device 6; The outlet of the de-hardening water tank 23 is connected to the inlet of the first water inlet booster pump 31, and after being pressurized, it enters the primary preheater 37, which adopts a plate heat exchanger and uses distilled water as the heat medium; the water outlet of the primary preheater 37 enters the secondary preheater 38, which adopts a shell and tube heat exchanger and uses low-pressure saturated steam as the heat medium, and the steam inlet is connected to the external steam pipe, and the steam is liquefied into distilled water after heat exchange and discharged to the distilled water tank 310; the water outlet of the secondary preheater 38 and the water outlet of the partial separator 35 enter the forced circulation The inlet pipe of the ring pump 33 enters the forced circulation evaporator 34 after being pressurized. The forced circulation evaporator 34 adopts a shell and tube heat exchanger, and the heat medium adopts the secondary steam compressed by the secondary steam compressor 39 to increase the thermal enthalpy; the water reaches the boiling point after heat exchange in the forced circulation evaporator 34, enters the separator 35, and the secondary steam is discharged from the separator 35, and the aqueous solution is concentrated; the secondary steam is connected to the inlet of the secondary steam compressor 39; during the operation of the MVR evaporation crystallization device 3, the vacuum pump 314 continues to operate to keep the MVR evaporation crystallization device 3 in a negative pressure state to reduce the boiling point of the aqueous solution; the inlet pipe of the vacuum pump 314 is provided with a condenser 315, and the condenser 315 adopts a shell and tube heat exchanger, and the cold medium adopts the circulating cooling water of the plant area, so that the small amount of steam extracted is cooled to condensed water; after the concentration of the aqueous solution in the separator 35 reaches the supersaturated state, it is discharged to the centrifuge 36 for dehydration by the discharge pump 351, and the solid impurities produced by the centrifuge 36 contain high organic matter, which are collected and sent to the hazardous waste treatment plant for treatment; the mother liquor discharged from the centrifuge enters the mother liquor tank 312, and returns to the separator 35 after being pressurized by the mother liquor pump 313; the compressed secondary steam is liquefied into distilled water after heat exchange in the forced circulation evaporator 34, and discharged to the distilled water tank 310, and enters the primary preheater 37 after being pressurized by the distilled water pump 311, and is discharged from the MVR evaporation crystallization device 3 after heat exchange, and enters the cooler 41 in the integrated sewage biological treatment device 4. The cooler 41 adopts an air-cooled cooler, and the distilled water quality is: TDS~1000mg / L, CODCr~500mg / L, PH 7~8.

[0028] The distilled water cooled by the cooler 41 enters the water inlet tank 42, and is lifted to the anoxic tank 44 and the aerobic tank 45 by the biochemical lifting pump 43. The anoxic tank 44 and the aerobic tank 45 adopt the biological contact oxidation method, and the filler adopts the hanging filler. The sewage is in full contact with the biofilm on the surface of the filler, and the COD, ammonia nitrogen, etc. in the sewage are removed by biodegradation. An aeration device is set at the bottom of the aerobic tank, and aeration and oxygenation are performed by the fan 452. According to the water quality requirements of the inlet / product water, carbon source and alkali are added. During the operation, the nitrification liquid reflux pump 451 is started to circulate part of the sewage from the aerobic tank 45 to the anoxic tank 44 to improve the removal rate of total nitrogen and COD. The effluent from the aerobic tank 45 flows by gravity into the second The sedimentation tank 46, the secondary sedimentation tank 46 adopts a vertical flow sedimentation tank, the effluent of the secondary sedimentation tank 46 flows by gravity into the inclined tube sedimentation tank 47, and the effluent of the inclined tube sedimentation tank 47 flows by gravity into the clear water tank 48. Coagulant is added at the water inlet of the secondary sedimentation tank 46 to improve the sedimentation effect. The secondary sedimentation tank 46 and the inclined tube sedimentation tank 47 regularly discharge the biochemical sludge to the sludge thickening tank 49, the supernatant of the sludge thickening tank 49 is discharged to the supernatant tank 410, and is lifted to the water inlet tank 42 by the supernatant pump 412 for recycling. The concentrated biochemical sludge at the bottom of the sludge thickening tank 49 is sent to the sludge treatment device 6 by the concentrated sludge pump 411. The water quality after biochemical treatment is: TDS~1000mg / L, CODCr<50mg / L, PH 7~8.

[0029] The outlet of the clean water tank 48 of the integrated sewage biological treatment device 4 is connected to the inlet of the second water inlet booster pump 581, and after being pressurized, it enters the quartz sand filter 511, the bag filter 512, and the ultrafiltration device 513. The ultrafiltration membrane has a filtration accuracy of 30nm, which can effectively remove suspended matter, colloids, microorganisms, bacteria, etc. in the water and protect the reverse osmosis membrane. The quartz sand filter 511 and the bag filter 512 are used to filter large particles of suspended matter and colloids in the water and protect the ultrafiltration membrane. The water produced by the ultrafiltration device 513 enters the ultrafiltration water production tank 52, and after being pressurized by the reverse osmosis booster pump 53, it enters the security filter 54, the reverse osmosis high-pressure pump 55, the reverse osmosis circulation pump 56 and finally enters the reverse osmosis device 57. The reverse osmosis device 57 adopts a concentrated water large flow circulation operation mode. Increasing the water flow rate on the membrane surface can reduce the pollution of COD to the membrane compared with the ordinary method. The recovery rate of the reverse osmosis device 57 reaches 90%, that is, the salt content of the influent is concentrated by about 10 times. The reverse osmosis product water enters the reverse osmosis water production tank 58 and is sent to the water reuse point in the plant area by the reverse osmosis water production pump 59. The reverse osmosis concentrated liquid returns to the sewage regulating tank 1; during the reverse osmosis operation, reducing agents, scale inhibitors, and non-oxidizing bactericides are added. The quartz sand filter 511 and the ultrafiltration device 513 need to be backwashed regularly. The reverse osmosis device 57 needs to be low-pressure flushed when it is started / shutdown. The backwash and flushing wastewater is discharged to the sludge concentration tank 49 of the integrated sewage biological treatment device 4 through the ditch. The water quality of the reverse osmosis device 57 produced water: TDS <20mg / L, CODCr <5mg / L, PH 6~7.

[0030] The sludge pool of the sludge treatment device 6 receives the chemical sludge discharged from the batch reaction precipitator 22 of the chemical hardness removal device and the concentrated biochemical sludge discharged from the sludge thickening tank 49 of the integrated sewage biological treatment device 4, and is pressurized by the sludge pump 62 and sent to the plate and frame filter press 63 for dehydration. After the sludge is dehydrated and dried, the moisture content is lower than 70%, and it becomes a mud cake, which is transported by the belt conveyor 65 and unloaded to the dehydrated sludge storage box 66 and transported to the hazardous waste treatment plant. The filtered water of the plate and frame filter press 63 is discharged to the sewage regulating tank 1 for recovery. The working steps of the plate and frame filter press 63 include pressing the filter plate, feeding, pressing, loosening the filter plate, unloading the mud, etc. The pressing adopts water pressing, and the water is supplied by the pressing water tank 641 and the pressing water pump 64 for recycling.

[0031] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A zero-discharge treatment process for high-salt organic wastewater from a hazardous waste treatment plant, characterized by: High-salt organic wastewater is first discharged into the sewage regulating tank. The wastewater in the sewage regulating tank is lifted to the chemical de-hardening device. After the chemical de-hardening device softens the wastewater, the generated chemical sludge is discharged to the sludge treatment device, dehydrated and transported to the hazardous waste treatment plant for treatment. The sludge filtered water returns to the sewage regulating tank. The effluent from the chemical de-hardening device enters distillation. The generated solid salts are sent to the hazardous waste treatment plant. The distillation generated is cooled and sent to the integrated sewage biological treatment device. The COD is reduced through biochemical treatment. The effluent from the integrated sewage biological treatment device enters the membrane treatment device. The reverse osmosis desalted water produced by the membrane treatment device is sent to the hazardous waste treatment plant workshop for reuse as process water. The reverse osmosis concentrate returns to the sewage regulating tank so that it can re-enter the system for the next round of treatment.

2. A zero-discharge treatment process for high-salt organic wastewater from a hazardous waste treatment plant according to claim 1, characterized in that: The chemical hardness removal device includes a caustic soda dosing device, a soda ash dosing device, a coagulant dosing device, a coagulant dosing device and a heavy metal capture agent dosing device for adding caustic soda, soda ash, a coagulant, a coagulant aid and a heavy metal capture agent to the sequencing batch reaction precipitator respectively; and also includes an acid adding device for adding an acidic agent to further reduce the hardness of water.

3. A zero-discharge treatment process for high-salt organic wastewater from a hazardous waste treatment plant according to claim 2, characterized in that: The de-hardened water from high-salt organic wastewater softened by the chemical de-hardening device is evaporated, condensed and centrifuged in the MVR evaporation and crystallization device to remove solid salts.

4. A zero-discharge treatment process for high-salt organic wastewater from a hazardous waste treatment plant according to claim 3, characterized in that: The integrated sewage biological treatment device comprises an inlet tank, an anoxic tank, an aerobic tank, a secondary sedimentation tank, an inclined tube sedimentation tank, and a clear water tank; the sewage treated by the MVR evaporation crystallization device enters the inlet tank, and is lifted to the anoxic tank and the aerobic tank by a biochemical lift pump; the anoxic tank and the aerobic tank adopt a biological contact oxidation method, and the filler adopts a hanging filler, so that the sewage is in full contact with the biofilm on the surface of the filler, and the COD and ammonia nitrogen in the sewage are removed by biodegradation; an aeration device is arranged at the bottom of the aerobic tank, and according to the water quality requirements of the inlet / product water, a carbon source and an alkali are added to the anoxic tank and the aerobic tank respectively through a carbon source adding device and an alkali adding device; during the operation, a nitrification liquid reflux pump is started to return part of the nitrification liquid to the aerobic tank; The sewage from the aerobic tank is circulated to the anoxic tank to improve the removal rates of total nitrogen and COD. At the same time, coagulant is added to the secondary sedimentation tank through the coagulant dosing equipment to accelerate the sedimentation process; the effluent from the aerobic tank flows by gravity into the secondary sedimentation tank, which adopts a vertical flow sedimentation tank. The effluent from the secondary sedimentation tank flows by gravity into the inclined tube sedimentation tank, and the effluent from the inclined tube sedimentation tank flows by gravity into the clear water tank. Coagulant is added at the water inlet of the secondary sedimentation tank to improve the sedimentation effect. The secondary sedimentation tank and the inclined tube sedimentation tank discharge the biochemical sludge to the sludge thickening tank at regular intervals, and the supernatant of the sludge thickening tank is discharged to the supernatant tank, which is lifted to the inlet tank by the supernatant pump for recycling. The concentrated biochemical sludge at the bottom of the sludge thickening tank is pumped to the sludge treatment device by the sludge thickening pump.

5. A zero-discharge treatment process for high-salt organic wastewater from a hazardous waste treatment plant according to claim 4, characterized in that: The sewage treated by the integrated sewage biological treatment device enters the membrane treatment device and is filtered to remove suspended matter, colloids, microorganisms and bacteria in the water.

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