Resourceful treatment system for wastewater with high organic matter content and high sodium nitrate content

Abstract

The utility model discloses a resourceful treatment system for wastewater with high organic matter content and high sodium nitrate content. The resourceful treatment system comprises a wastewater pretreatment system, a nanofiltration unit, a sodium chloride evaporation unit, a sodium nitrate freezing unit, a sodium sulfate evaporation unit, a wet catalytic oxidation device, a mixed salt evaporation unit and a carnallite drying unit. The device has the advantages that the device is simple in connecting structure and easy to realize, sodium nitrate crystal salt is not produced in the rear-end mixed salt evaporation process, and meanwhile, the part of sodium nitrate has higher economic benefits; the concentration multiple of mixed salt evaporation is improved, and the amount of dried carnallite is reduced, so that the carnallite treatment cost is reduced.

Description

Technical field:

[0001] The utility model relates to a wastewater treatment system, in particular to a wastewater resource treatment system containing high organic matter and high sodium nitrate. Background technology:

[0002] At present, the components of wastewater generated by industrial production are complex. The wastewater discharged by some enterprises contains not only sodium sulfate and sodium chloride, but also some ammonia salts, nitrates, etc., and also contains relatively high organic matter. The existing sewage treatment methods usually adopt the form of biochemical + reclaimed water + zero discharge to extract sodium sulfate and sodium chloride from the wastewater, but the remaining sodium nitrate basically exists in the miscellaneous salts, resulting in the final output of a large amount of miscellaneous salts and poor resource utilization. Utility model content:

[0003] The utility model aims to provide a high-organic matter and high-sodium nitrate wastewater resource treatment system which has a simple connection structure, improves economic benefits, and reduces the cost of miscellaneous salt disposal.

[0004] The utility model is implemented by the following technical scheme: The purpose of this patent is to provide a high-organic matter, high-sodium nitrate wastewater resource treatment system, which includes a wastewater pretreatment system, a nanofiltration unit, a sodium chloride evaporation unit, a sodium nitrate freezing unit, a sodium sulfate evaporation unit, a wet catalytic oxidation device, a mixed salt evaporation unit and a mixed salt drying unit; the water outlet of the wastewater pipeline is connected to the water inlet of the wastewater pretreatment system; the water outlet of the wastewater pretreatment system is connected to the water inlet of the nanofiltration unit, and the water outlet of the nanofiltration unit is connected to the water inlet of the sodium chloride evaporation unit. The mother liquor outlet of the sodium chloride evaporation unit is connected to the liquid inlet of the sodium nitrate freezing unit, the concentrated water outlet of the nanofiltration unit is connected to the liquid inlet of the sodium sulfate evaporation unit, the mother liquor outlets of the sodium nitrate freezing unit and the sodium sulfate evaporation unit are evenly connected to the liquid inlet of the wet catalytic oxidation device, the liquid outlet of the wet catalytic oxidation device is connected to the liquid inlet of the mixed salt evaporation unit, the discharge port of the mixed salt evaporation unit is connected to the feed port of the wastewater pretreatment system; the mother liquor outlet of the mixed salt evaporation unit is connected to the liquid inlet of the mixed salt drying unit.

[0005] Furthermore, the wastewater pretreatment system includes a primary sedimentation tank, a regulating tank, a high-density tank for hardness and silicon removal, an ultrafiltration membrane unit and a reverse osmosis unit which are connected in sequence, and the concentrate outlet of the reverse osmosis unit is connected to the water inlet of the nanofiltration unit; the outlet end of the wastewater pipeline and the outlet of the mixed salt evaporation unit are evenly connected to the inlet of the primary sedimentation tank.

[0006] The utility model has the following advantages: the utility model has a simple connection structure and is easy to implement. The treatment system extracts most of the sodium nitrate in the sodium chloride mother liquor by adding a sodium nitrate freezing unit, thereby ensuring that no sodium nitrate crystal salt is produced during the mixed salt evaporation process at the rear end, and this part of the sodium nitrate has higher economic benefits. Moreover, the system adds a wet catalytic oxidation device before entering the mixed salt to degrade the organic matter in the mother liquor before entering the mixed salt evaporation unit, thereby increasing the concentration multiple of the mixed salt evaporation, reducing the amount of mixed salt to be dried, and thus reducing the cost of miscellaneous salt disposal. Description of the drawings:

[0007] In order to more clearly illustrate the embodiments of the utility model 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 described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0008] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0009] Wastewater pretreatment system 1, primary sedimentation tank 11, regulating tank 12, high-density tank for hardness and silicon removal 13, ultrafiltration membrane unit 14, reverse osmosis unit 15, nanofiltration unit 2, sodium chloride evaporation unit 3, sodium nitrate freezing unit 4, sodium sulfate evaporation unit 5, wet catalytic oxidation device 6, mixed salt evaporation unit 7, mixed salt drying unit 8, wastewater pipeline 9. Specific implementation method:

[0010] Example: Figure 1 As shown, a system for resource treatment of high-organic matter and high-sodium nitrate wastewater includes a wastewater pretreatment system 1, a nanofiltration unit 2, a sodium chloride evaporation unit 3, a sodium nitrate freezing unit 4, a sodium sulfate evaporation unit 5, a wet catalytic oxidation device 6, a mixed salt evaporation unit 7 and a mixed salt drying unit 8; the water outlet of the wastewater pipeline 9 is connected to the water inlet of the wastewater pretreatment system 1; the water outlet of the wastewater pretreatment system 1 is connected to the water inlet of the nanofiltration unit 2, the water outlet of the nanofiltration unit 2 is connected to the water inlet of the sodium chloride evaporation unit 3, and the sodium chloride The mother liquor outlet of the evaporation unit 3 is connected to the liquid inlet of the sodium nitrate freezing unit 4, the concentrated water outlet of the nanofiltration unit 2 is connected to the liquid inlet of the sodium sulfate evaporation unit 5, the mother liquor outlets of the sodium nitrate freezing unit 4 and the sodium sulfate evaporation unit 5 are connected to the liquid inlet of the wet catalytic oxidation device 6, the liquid outlet of the wet catalytic oxidation device 6 is connected to the liquid inlet of the mixed salt evaporation unit 7, the material outlet of the mixed salt evaporation unit 7 is connected to the material feed inlet of the wastewater pretreatment system 1; the mother liquor outlet of the mixed salt evaporation unit 7 is connected to the liquid inlet of the mixed salt drying unit 8.

[0011] The wastewater pretreatment system 1 includes a primary sedimentation tank 11, a regulating tank 12, a high-density tank 13 for hardness and silicon removal, an ultrafiltration membrane unit 14 and a reverse osmosis unit 15 which are connected in sequence. The concentrated water outlet of the reverse osmosis unit 15 is connected to the water inlet of the nanofiltration unit 2; the outlet end of the wastewater pipeline 9 and the discharge port of the mixed salt evaporation unit 7 are evenly connected to the inlet of the primary sedimentation tank 11.

[0012] Working principle:

[0013] 1) High-organic matter and high-sodium nitrate wastewater first passes through the wastewater pretreatment system 1 for hardness removal, silicon removal, and double membrane pretreatment before entering the nanofiltration unit 2 for salt separation;

[0014] 2) After the salt separation in the nanofiltration unit 2, the produced water mainly contains sodium chloride + sodium nitrate, and the concentrated water mainly contains sodium sulfate and a very small amount of sodium nitrate;

[0015] 3) The water produced by the nanofiltration is passed through the sodium chloride evaporation unit 3 to produce sodium chloride crystal salt (purity ≥ 97%), and the mother liquor of the sodium chloride evaporation contains a large amount of sodium nitrate;

[0016] 4) The sodium chloride evaporation mother liquor enters the sodium nitrate freezing unit 4 to freeze out sodium nitrate crystals (purity ≥ 98%), and most of the sodium nitrate in the sodium chloride mother liquor is extracted to ensure that no sodium nitrate crystals are produced during the rear mixed salt evaporation process, and this part of sodium nitrate has a higher economic benefit;

[0017] 5) The concentrated water from the nanofiltration passes through a sodium sulfate evaporation unit 5 to crystallize sodium sulfate crystalline salt;

[0018] 6) The frozen mother liquor of sodium nitrate and the evaporated mother liquor of sodium sulfate enter the wet catalytic oxidation device 6 together to reduce the organic matter content in the mother liquor, and then enter the mixed salt evaporation unit 7 after the organic matter in the mother liquor is degraded, thereby increasing the concentration multiple of the mixed salt evaporation and reducing the amount of mixed salt to be dried, thereby reducing the cost of miscellaneous salt disposal;

[0019] 7) The effluent from the wet catalytic oxidation device 6 enters the mixed salt evaporation unit 7 to crystallize a mixed salt of sodium chloride + sodium sulfate, which is sent to the primary sedimentation tank 11 to dissolve and then, after being pre-treated with the wastewater, is separated again by the nanofiltration unit 2;

[0020] 8) The mixed salt evaporation mother liquor enters the impure salt drying unit 8 to crystallize the impure salt.

[0021] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 system for recycling wastewater containing high organic matter and high sodium nitrate, characterized in that: The invention comprises a wastewater pretreatment system, a nanofiltration unit, a sodium chloride evaporation unit, a sodium nitrate freezing unit, a sodium sulfate evaporation unit, a wet catalytic oxidation device, a mixed salt evaporation unit and a mixed salt drying unit; the water outlet of the wastewater pipeline is connected with the water inlet of the wastewater pretreatment system; the water outlet of the wastewater pretreatment system is connected with the water inlet of the nanofiltration unit, the water production outlet of the nanofiltration unit is connected with the water inlet of the sodium chloride evaporation unit, the mother liquor outlet of the sodium chloride evaporation unit is connected with the liquid inlet of the sodium nitrate freezing unit, the concentrated water outlet of the nanofiltration unit is connected with the liquid inlet of the sodium sulfate evaporation unit, the mother liquor outlets of the sodium nitrate freezing unit and the sodium sulfate evaporation unit are evenly connected with the liquid inlet of the wet catalytic oxidation device, the liquid outlet of the wet catalytic oxidation device is connected with the liquid inlet of the mixed salt evaporation unit, the material outlet of the mixed salt evaporation unit is connected with the material inlet of the wastewater pretreatment system; the mother liquor outlet of the mixed salt evaporation unit is connected with the liquid inlet of the mixed salt drying unit.

2. A high-organic matter and high-sodium nitrate wastewater resource treatment system according to claim 1, characterized in that: The wastewater pretreatment system includes a primary sedimentation tank, a regulating tank, a high-density tank for hardness and silicon removal, an ultrafiltration membrane unit and a reverse osmosis unit which are connected in sequence. The concentrated water outlet of the reverse osmosis unit is connected to the water inlet of the nanofiltration unit; the water outlet end of the wastewater pipeline and the discharge port of the mixed salt evaporation unit are evenly connected to the inlet of the primary sedimentation tank.

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