Process-simplified high-salinity wastewater zero-discharge synergistic saline-alkali soil treatment device

Abstract

The utility model particularly relates to a process-simplified high-salinity wastewater zero-discharge synergistic saline-alkali land treatment device which is characterized in that the water outlet end of a high-salinity wastewater regulation reservoir is connected with the water inlet end of a wastewater pretreatment unit through a pipeline, and the water outlet end of the wastewater pretreatment unit is connected with the water inlet end of an RO (Reverse Osmosis) pre-concentration unit through a pipeline; the concentrated water end of the RO pre-concentration unit is connected with the water inlet end of the ultra-concentration RO membrane unit through a pipeline, the concentrated water end of the ultra-concentration RO membrane unit is connected with the water inlet end of the sodium sulfate saline water blending tank through a pipeline, and the water outlet end of the sodium sulfate saline water blending tank is connected with the inlet end of the double decomposition reaction device through a pipeline; and the discharge end of the double decomposition reaction device is connected with the compounding and mixing device through a pipeline. According to the utility model, the process is simplified, the investment cost is reduced, and the resource utilization rate is high.

Description

Technical Field

[0001] The utility model belongs to the technical field of saline-alkali land treatment, and in particular relates to a high-salt wastewater zero-discharge collaborative saline-alkali land treatment device with a simplified process. Background Art

[0002] Currently, the most effective method for managing saline-alkali soils is soil leaching, which consumes significant amounts of freshwater. Brine generated by agricultural irrigation and leaching of salt from saline-alkali land, as well as agricultural non-point source pollution, accounts for approximately 30% of total irrigation water. Discharge into rivers and lakes poses a serious threat to the water environment and ecology of the basin, and leads to the continuous worsening of secondary soil salinization. The national government has strictly prohibited the discharge of brine, making leaching a non-point source of pollution in saline-alkali lands impossible.

[0003] The inventor of this application, Cao Cheng, applied to the Patent Office of China for a utility model patent entitled "A Zero Discharge Device for High-salt Wastewater" on January 16, 2023. The patent was authorized and announced on May 26, 2023, with the authorization announcement number CN219079306U. It abandons the nanofiltration salt separation and subsequent RO re-concentration, ED concentration, evaporation and freezing crystallization process sections in the existing high-salt wastewater zero discharge device, greatly reducing the investment and operating costs of environmental protection facilities. At the same time, it uses chemical technology to achieve high-salt wastewater pollutant emission reduction and resource utilization, and uses RO concentrated concentrated water or nanofiltration salt separation after water and concentrated water as one of the raw materials for chemical production to produce industrial-grade baking soda, ammonium chloride, ammonium sulfate or potassium sulfate, realizing the transformation of negative benefits into positive benefits, while taking into account ecological protection and economic benefits, and promoting environmental protection projects to truly achieve synergistic efficiency in pollution control, emission reduction and carbon reduction and long-term sustainable operation.

[0004] The above technical solution still has the defect of insufficient process simplification. It adopts nanofiltration for salt separation. The water production end is mainly sodium chloride solution, and the concentration end is mainly sodium sulfate solution. Two sets of independent double decomposition reaction devices are required to perform double decomposition reactions respectively to generate sodium bicarbonate, ammonium chloride and sodium bicarbonate, ammonium sulfate, respectively. The investment in the two independent devices is large.

[0005] Simplifying the zero-discharge treatment of high-salt wastewater and synergistically combining the zero-discharge treatment of high-salt wastewater with saline-alkali land management have become technical problems that technical personnel in this field urgently need to solve. Utility Model Content

[0006] The purpose of this utility model is to provide a high-salt wastewater zero-discharge collaborative saline-alkali land treatment device with a simplified process, which realizes the resource utilization of unconventional "new water sources" such as saline-alkali land washing brine and agricultural non-point source pollution water, realizes the regeneration of high-salt waste liquid and industrial waste salt, and completely solves the dilemma of high-salt wastewater discharge in the desalination of saline-alkali land washing brine, realizes high-level utilization of water resources by quality gradient, and has significant ecological, economic and social benefits.

[0007] The utility model is realized through the following technical solutions:

[0008] That is, a high-salt wastewater zero-discharge technology coordinated saline-alkali land treatment device, which is characterized by comprising a high-salt wastewater regulating and storage pool, the outlet end of the high-salt wastewater regulating and storage pool is connected to the water inlet end of the wastewater pretreatment unit through a pipeline, the outlet end of the wastewater pretreatment unit is connected to the water inlet end of the RO pre-concentration unit through a pipeline, the concentrated water end of the RO pre-concentration unit is connected to the water inlet end of the super-concentrated RO membrane unit through a pipeline, the concentrated water end of the super-concentrated RO membrane unit is connected to the water inlet end of the sodium sulfate brine mixing tank through a pipeline, and the water outlet end of the sodium sulfate brine mixing tank is connected to the water inlet end of the sodium sulfate brine mixing tank through a pipeline. It is connected to the inlet end of the double decomposition reaction device, the discharge end of the double decomposition reaction device is connected to the compounding and mixing device through a pipeline, the RO pre-concentration unit, the super-concentration RO membrane unit and the water production end of the double decomposition reaction device, and the discharge end of the compounding and mixing device are respectively connected to the saline-alkali land treatment unit through management, the brine and polluted water generated by the saline-alkali land treatment unit are connected to the water inlet end of the brine and agricultural non-point source pollution water collection unit through a pipeline, and the water outlet end of the brine and agricultural non-point source pollution water collection unit is connected to the water inlet end of the high-salt wastewater storage tank through management.

[0009] The high-salt wastewater regulating and storage tank, wastewater pretreatment unit, RO pre-concentration unit, super-concentrated RO membrane unit, sodium sulfate brine mixing tank, double decomposition reaction device, saline-alkali land treatment unit, and washing brine and agricultural non-point source pollution water collection unit of the utility model form a closed circulation loop to achieve zero discharge of wastewater.

[0010] Compared with CN219079306U, the utility model omits the low-pressure nanofiltration salt separation unit when treating high-salt wastewater, and adds an ultra-concentration RO membrane unit, thereby achieving low-energy consumption and high-concentration of wastewater, with the maximum salt concentration reaching 210g / l. Concentrated brine is used as the production raw material, ammonium bicarbonate is added, and sodium bicarbonate, ammonium chloride and ammonium sulfate are produced through a double decomposition reaction device.

[0011] The utility model does not adopt nanofiltration salt separation. The highly concentrated brine is directly concentrated and modulated by the super-concentrated RO membrane unit and then directly enters a set of double decomposition reaction device. The design of the double decomposition reaction device is optimized to directly generate sodium bicarbonate, ammonium chloride and ammonium sulfate, simplifying the process flow, reducing investment and improving efficiency.

[0012] The utility model adopts a double decomposition thermal method to produce alkali, wherein saturated brine and solid ammonium bicarbonate are subjected to double decomposition reaction to generate sodium bicarbonate precipitate, which is filtered and washed to obtain NaHCO3 crystals, which are then calcined to obtain a soda ash product. After filtering, the filtrate is first heated to remove ammonia and carbon dioxide, and then evaporated and salted, and cooled to precipitate ammonium chloride and ammonium sulfate respectively.

[0013] The double decomposition thermal method and alkali-coated process are used to produce soda ash, ammonium chloride and ammonium sulfate, which effectively solves the environmental protection problems of waste salt and waste liquid treatment, makes resources reasonably allocated, meets the circular economy development requirements put forward by the country, and is environmentally friendly.

[0014] In this scheme, brackish water, high-salt wastewater, saline-alkali land washing wastewater, and agricultural non-point source pollution are treated by this device. The resulting desalinated water is used for industrial and agricultural irrigation, as well as saline-alkali land treatment and leaching. Agricultural non-point source pollution generated by agricultural irrigation and saline-alkali land leaching is recycled, achieving water resource recycling and salt and nitrogen recycling. The baking soda produced by this device is supplied to the market, while ammonium sulfate and ammonium chloride are mixed with additives to produce compound nitrogen fertilizer, which is applied to saline-alkali land and supplied to the market.

[0015] The reactor and crystallizer of the double decomposition reaction device of the present invention are both mature commercial products in the prior art, and those skilled in the art are aware of their structures and usage methods.

[0016] The compound mixing device of the present invention can use a compound fertilizer granulation production device known in the prior art, such as, but not limited to, the invention patent technology of a novel compound fertilizer granulation production system, which was published by the Patent Office of China on December 24, 2014, with publication number CN104230438A.

[0017] The compound mixing device of the utility model uses ready-made single fertilizers, compound fertilizers or chemical raw materials (such as urea, ammonium phosphate, potassium chloride, potassium sulfate, calcium sulfate, ammonium sulfate, ammonium chloride, etc.) as raw materials, supplemented with additives, and mixes, processes and granulates to produce fertilizers.

[0018] The saline-alkali land treatment unit of the present invention refers to the treatment of saline-alkali land by using saline-alkali land treatment methods known in the prior art. For example, saline-alkali land is repaired by physical means such as soil addition, sand pressing, terraced fields, water pressure salt removal, film covering, straw covering, etc., and chemical measures such as adding organic acid, inorganic acid, desulfurization gypsum, aluminum sulfate, biochar, furfural residue, organic polymers, biological strains, organic fertilizers, and plant repair measures to achieve the goals of desalination, salt washing, salt removal, and salt control, thereby making saline-alkali land arable, and selecting salt-alkali tolerant crops such as cotton, rice, sugar beets, and forage grass to increase production and efficiency.

[0019] The utility model discloses a salt water washing and agricultural non-point source pollution water collection unit, which is a discharge collection pipeline system for collecting saline-alkali land salt washing wastewater and farmland pollution water.

[0020] The utility model simplifies the process, reduces investment cost, has high resource utilization, does not produce any secondary pollution such as industrial waste salt and hazardous waste mother liquor miscellaneous salt, realizes the resource utilization of unconventional "new water sources" such as saline-alkali land washing brine and agricultural non-point source pollution water, and simultaneously produces baking soda, ammonium chloride, and ammonium sulfate, realizes the recycling of high-salt waste liquid and industrial waste salt, and completely solves the dilemma of high-salt wastewater discharge in the desalination of saline-alkali land washing brine, realizes high-level utilization of water resources by quality gradient, and has significant ecological environmental benefits, economic benefits, and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural diagram of the utility model;

[0022] As shown in the figure: 1. High-salt wastewater storage tank; 2. Wastewater pretreatment unit; 3. RO pre-concentration unit; 4. Super RO concentration unit; 5. Sodium sulfate brine mixing tank; 6. Double decomposition reaction unit; 10. Compound mixing unit; 11. Saline-alkali land treatment unit; 12. Wash brine and agricultural non-point source pollution water collection unit. DETAILED DESCRIPTION

[0023] The following is a detailed description of the embodiments of the technical solution of the present invention in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention. It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0024] like Figure 1 As shown: a high-salt wastewater storage tank 1, a wastewater pretreatment unit 2, an RO pre-concentration unit 3, a super-RO concentration unit 4-1, a sodium sulfate brine blending tank 5, and a double decomposition reaction device 6 are connected in sequence by pipelines. The double decomposition reaction device 5 includes a reactor and a crystallizer. The crystallizer discharge port of the double decomposition reaction device 6 is connected to the feed port of the compounding and mixing device 10 through a pipeline. The discharge port of the compounding and mixing device 10 is connected to the saline-alkali land treatment unit 11 through a pipeline. The produced water of the RO pre-concentration unit 3 and the super-RO concentration unit 4-1 and the condensed water of the double decomposition reaction device 6 are respectively connected to the saline-alkali land treatment unit 11 through pipelines. The saline-alkali land washing brine and agricultural non-point source pollution water generated during the treatment of the saline-alkali land treatment unit 11 are collected by the washing brine and agricultural non-point source pollution water collection unit 12 and sent back to the high-salt wastewater storage tank 1 through a pipeline to form a circulation loop.

[0025] When the utility model is used, saline-alkali land salt washing wastewater, agricultural non-point source pollution water, brackish water and high-salt wastewater enter the wastewater pretreatment unit 2 through the high-salt wastewater regulating and storage pool 1 to remove hardness, impurities and reduce COD, and then enter the RO pre-concentration unit 3, and the produced water is reused for industrial and saline-alkali land elution; the concentrated water is further concentrated by the super-concentration RO membrane unit 4 and reused for industrial and saline-alkali land elution; the concentrated water is sodium sulfate and sodium chloride concentrated liquid as production raw materials, which are prepared in the sodium sulfate brine preparation tank 5 as production raw materials, and ammonium bicarbonate is added to generate baking soda (sodium bicarbonate) precipitation and crystallization through the double decomposition reaction device 6, the filtrate is evaporated and salt is precipitated, and ammonium sulfate and ammonium chloride are precipitated by cooling, and the evaporated condensed water is used for industrial and saline-alkali land elution; the ammonium chloride and ammonium sulfate enter the compound mixing device 7 and are compounded with additives to form compound nitrogen fertilizer, which is applied to the saline-alkali land. The saline-alkali land salt washing wastewater and agricultural non-point source pollution water generated by saline-alkali land treatment and development are collected by the salt washing water and agricultural non-point source pollution water collection unit 12 and then circulated back to the high-salt wastewater storage tank 1 to form a closed-loop circulation.

[0026] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A simplified process high-salt wastewater zero-discharge collaborative saline-alkali land treatment device, characterized in that The high-salt wastewater regulating and storage tank comprises a water outlet of the high-salt wastewater regulating and storage tank and a water inlet of a wastewater pretreatment unit through a pipeline, a water outlet of the wastewater pretreatment unit and a water inlet of an RO pre-concentration unit through a pipeline, a concentrated water end of the RO pre-concentration unit and a water inlet of an ultra-concentrated RO membrane unit through a pipeline, a concentrated water end of the ultra-concentrated RO membrane unit and a water inlet of a sodium sulfate brine blending tank through a pipeline, a water outlet of the sodium sulfate brine blending tank and an inlet of a double decomposition reaction device through a pipeline. The discharge end of the double decomposition reaction device is connected to the compounding and mixing device through a pipeline, the RO pre-concentration unit, the super-concentration RO membrane unit and the water production end of the double decomposition reaction device, and the discharge end of the compounding and mixing device are respectively connected to the saline-alkali land treatment unit through management, the brine and polluted water produced by the saline-alkali land treatment unit are connected to the water inlet end of the brine and agricultural non-point source pollution water collection unit through a pipeline, and the water outlet end of the brine and agricultural non-point source pollution water collection unit is connected to the water inlet end of the high-salt wastewater storage tank through management.

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