CN115893763A - A zero-discharge and resource-based treatment system and method for high-salt wastewater - Google Patents

Abstract

The invention discloses a high-salinity wastewater zero-discharge and recycling treatment system and a method, wherein the high-salinity wastewater zero-discharge and recycling treatment system comprises a high-efficiency sedimentation tank device, a high-efficiency filtering device, an ultrafiltration device, an ion exchange device, a stripping device and an advanced catalytic oxidation device which are sequentially connected according to a treatment process of high-salinity wastewater; the water production side of the nanofiltration device is sequentially connected with a concentration electrodialysis device and a bipolar membrane electrodialysis device; the concentrated water side of the nanofiltration device is connected with an evaporation crystallization device. According to the invention, the high-efficiency precipitation tank is adopted for removing hard silicon, nano-filtration and salt separation, the electrodialysis device is used for concentrating, the bipolar membrane electrodialysis is used for preparing acid and alkali with higher added values for recycling, evaporation crystallization is used for treating high-salinity wastewater, and finally recyclable evaporation condensate water, hydrochloric acid, liquid alkali and an externally-sold industrial-grade anhydrous sodium sulfate product are produced, so that zero discharge and recycling of the high-salinity wastewater are realized, and further, the economic benefit is maximized.

Description

A zero-discharge and resource-based treatment system and method for high-salt wastewater

technical field

The invention relates to the technical field of high-salt wastewater treatment, in particular to a high-salt wastewater zero discharge and resource treatment system and method.

Background technique

At present, the national industrial water intake accounts for 20% of the national water intake. Industrial wastewater is treated by traditional processes to obtain high-salt, refractory industrial wastewater. With the rapid development of my country's industry, the discharge of high-salt wastewater is increasing day by day. At the same time, environmental protection policies are becoming increasingly stringent. Not only are there limited quotas for wastewater discharge indicators in industrial parks, but coal chemical companies, coal companies, and coal-fired power plants are required to have no industrial wastewater discharge. Therefore, the promotion and development of zero-discharge wastewater technology in the coal chemical industry, coal mine water industry, desulfurization wastewater industry of coal-fired power plants, industrial park sewage treatment plants, landfill leachate treatment plants, etc. is an inevitable requirement for efficient use of water resources.

At present, the processes for zero discharge and resource treatment of high-salt wastewater are generally pretreatment, membrane concentration (concentration treatment with various types of membranes to obtain high-salt wastewater and reuse water), nanofiltration salt separation or evaporation crystallization salt separation Combination process. The main feature of this process is to remove scaling factors such as calcium, magnesium, and silicon in wastewater through pretreatment, reduce the amount of wastewater and increase the concentration of salt through membrane concentration, and realize monovalent salt and divalent salt through nanofiltration membrane group. For salt pre-salting, use evaporation, concentration and crystallization to produce crystallized salt or use thermal salt and nitrate co-production to directly separate salt.

However, the above-mentioned process has the following disadvantages: (1) During the process of membrane concentration, the salt in the water is constantly enriched, and the organic matter is also increasing in a large amount, which aggravates the organic fouling of the reverse osmosis membrane group and makes the reverse osmosis membrane group The stable operation period is shortened, affecting the long-term stable operation of the system and increasing the system operation and maintenance costs; (2) The operating pressure of conventional membrane concentration is high, and the salt (TDS) can only be concentrated to about 50000mg/L, and the recovery rate of water (3) The combination process of reverse osmosis membrane concentration and evaporation crystallization to separate sodium sulfate and sodium chloride system requires high front-end pretreatment dosing costs, high investment and operating costs for reverse osmosis membrane groups, and high output (4) When the system is running poorly, a large amount of industrial salt is often characterized as mixed salt, causing huge waste disposal costs to the enterprise.

Therefore, in view of the problems in the above-mentioned process, it is necessary to adopt a low-cost method to effectively separate sodium sulfate and sodium chloride in wastewater, and make acid-base with higher added value from sodium chloride high-salt wastewater as a medicament It is reused in the front-end pretreatment unit to realize the deep resource utilization of high-salt wastewater; the anhydrous sodium sulfate product with high recovery value is sold as a resource; at the same time, more than 90% of the evaporated condensed water that meets the reuse requirements is recovered, and finally realized The goal of zero discharge and resource treatment and recycling of high-salt wastewater.

Contents of the invention

The technical solution adopted by the present invention to solve the technical problem is: a high-salt wastewater zero-discharge and resource-based treatment system, including:

The high-efficiency sedimentation tank device is used to connect high-salt wastewater for softening pretreatment, and precipitate impurities such as calcium, magnesium, silicon, heavy metal ions, and larger suspended solids in high-salt wastewater to obtain primary treated water;

A high-efficiency filtration device and an ultrafiltration device, the primary treatment water passes through the high-efficiency filtration device and the ultrafiltration device in sequence, and the smaller suspended solids and colloids in the primary treatment water are removed to obtain secondary treatment water;

An ion exchange device for further removing residual calcium, magnesium, and heavy metals in the secondary treatment water to obtain resin produced water;

The stripping device is used to remove the alkalinity of the resin produced water, adjust the pH value of the resin produced water by adding hydrochloric acid, and remove the carbonate reaction therein, and then obtain the decarbonized produced water;

An advanced catalytic oxidation device is used to perform COD removal treatment and activated carbon adsorption treatment on the decarbonized produced water, remove organic impurities and chroma removal treatment in the decarbonized produced water, and obtain tertiary treated water;

The nanofiltration device is used to separate and purify the three times of treated water, and then generate nanofiltration product water of monovalent ion sodium chloride and nanofiltration concentrated water based on divalent ion sodium sulfate;

Concentration electrodialysis device, used to receive the nanofiltration product water, and high-fold concentration of the nanofiltration product water to obtain high-concentration sodium chloride brine;

A bipolar membrane electrodialysis device is used to electrolyze the sodium chloride brine to obtain hydrochloric acid and liquid caustic soda;

Wherein, the hydrochloric acid and liquid caustic soda produced by the bipolar membrane electrodialysis device are returned to the high-efficiency sedimentation tank device and the stripping device through pipelines for recycling.

Preferably, the high-efficiency sedimentation tank device includes a primary coagulation tank, a secondary coagulation tank, a flocculation tank, a sedimentation tank, a pH adjustment tank, and a sludge return pump, and the high-salt wastewater passes through the primary coagulation tank, Secondary coagulation tank, flocculation tank, sedimentation tank, the high-salt wastewater in the sedimentation tank is layered to form water phase and activated sludge, and the water phase enters the pH adjustment tank to form the primary treatment water, The activated sludge is returned to the primary coagulation tank through the sludge return pump.

As preferably, the liquid caustic soda produced by the bipolar membrane electrodialysis device is added in the first-stage coagulation tank, sodium carbonate is added in the secondary coagulation tank, flocculant is added in the described coagulation tank, As a coagulation aid, the hydrochloric acid produced by the bipolar membrane electrodialysis device is added to the pH adjustment tank.

As a preference, the advanced catalytic oxidation device includes an advanced catalytic oxidation tower and an activated carbon adsorption tower, and the decarburized water passes through the advanced catalytic oxidation tower and the activated carbon adsorption tower in turn, and the advanced catalytic oxidation tower and the activated carbon adsorption tower make The COD removal rate of the decarbonized water is 35%-45%.

Preferably, an evaporative crystallization device is also included, and the evaporative crystallization device is used for evaporative crystallization of the nanofiltration concentrated water to produce anhydrous sodium sulfate.

Also disclosed is a zero-discharge and resource-based treatment method for high-salt wastewater, including:

S1. The high-efficiency sedimentation tank is connected to the high-salt wastewater for softening pretreatment, and precipitates impurities such as calcium, magnesium, silicon, heavy metal ions, and larger suspended solids in the high-salt wastewater to obtain primary treated water;

S2, the primary treatment water passes through a high-efficiency filtration device and an ultrafiltration device successively to remove smaller suspended matter and colloids in the primary treatment water to obtain secondary treatment water;

S3. Removing calcium, magnesium and heavy metals remaining in the secondary treatment water through an ion exchange device to obtain resin produced water;

S4. The stripping device performs alkalinity removal treatment on the resin product water, adjusts the pH value of the resin product water by adding hydrochloric acid, and removes the carbonate reaction therein, and then obtains the decarbonized product water;

S5. Perform COD removal treatment and activated carbon adsorption treatment on the decarbonized product water through an advanced catalytic oxidation device to remove organic impurities and chroma removal treatment in the decarbonized product water to obtain tertiary treated water;

S6. Separating and purifying the tertiary treated water to generate nanofiltration product water of monovalent ion sodium chloride and nanofiltration concentrated water mainly of divalent ion sodium sulfate;

S7. High-fold concentration of the nanofiltration product water to obtain high-concentration sodium chloride brine;

S8. Electrolyzing the sodium chloride brine to obtain hydrochloric acid and liquid caustic soda;

The hydrochloric acid and liquid caustic soda produced in S8 are returned to the high-efficiency sedimentation tank device and the stripping device through pipelines for recycling.

As a preference, in S1, the high-efficiency wastewater passes through the primary coagulation tank, the secondary coagulation tank, the flocculation tank, the sedimentation tank, and the pH adjustment tank in sequence, and the high-salt wastewater in the sedimentation tank is stratified to form an aqueous phase and an active sludge, the water phase enters the pH adjustment tank to form the primary treatment water, and the activated sludge is returned to the primary coagulation tank through the sludge return pump.

As preferably, the liquid caustic soda produced in step S8 is added to the primary coagulation tank in S1, sodium carbonate is added to the secondary coagulation tank, flocculant is added to the coagulation aid in the coagulation tank Agent, the hydrochloric acid produced in step S8 is added to the pH adjustment tank.

Preferably, in S5, the decarbonized product water passes through the advanced catalytic oxidation tower and the activated carbon adsorption tower in sequence, and the organic matter and chroma in the decarbonized product water are removed through the advanced catalytic oxidation tower and the activated carbon adsorption tower.

Preferably, it also includes S9, which is used for evaporating and crystallizing the nanofiltration concentrated water to produce anhydrous sodium sulfate through a crystallization device.

Beneficial effects of the present invention:

The effective separation and high-fold concentration of sodium chloride and sodium sulfate in high-salt wastewater have been realized, and the high-value-added acid-base produced from high-concentration sodium chloride and high-salt wastewater can be reused in the front-end system as the self-use agent of the system to obtain high-quality Anhydrous sodium sulfate products with market value and evaporative condensed water that meet the requirements of reuse save the investment and operating costs of equipment to obtain sodium chloride products through evaporation and crystallization of high-concentration sodium chloride brine; realize the deep resource utilization of high-salt wastewater to the greatest extent And obtain products with high market value, and finally achieve the goal of zero discharge and resource treatment of high-salt wastewater.

Description of drawings

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is the partially enlarged view of part A in Fig. 1 of the present invention;

Fig. 3 The evaporative condensed water cooling device of the present invention.

In the picture:

1. High-efficiency sedimentation tank; 101. Primary coagulation tank; 102. Secondary coagulation tank; 103. Flocculation tank; 104. Sedimentation tank; 105. pH adjustment tank; 2. High-efficiency filter; 3. Ultrafiltration device; 4. Ion exchange device; 5. Stripping device; 6. Advanced catalytic oxidation device; 7. Nanofiltration device; 8. Concentration electrodialysis device; 9. Two-stage membrane electrodialysis device; 10. Evaporation crystallization device; 11. Evaporation raw water tank; 12. Evaporation raw water pump; 13. Heat exchanger; 14. Condensate water pump; 15. Condensate water tank; 16. Reuse water pool.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

The following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

A high-salt wastewater zero-discharge and resource-based treatment system of the present invention, please refer to Figure 1-3, includes a high-efficiency sedimentation tank device for removing calcium, magnesium, and silicon scaling ions connected to high-salt wastewater. High-efficiency filtration device 2 and ultrafiltration device 3 for filtering salty wastewater, ion exchange device 4 for further softening filtered high-salt wastewater, stripping device 5 for removing residual alkalinity from further softened high-salt wastewater, Advanced catalytic oxidation device for reducing organic matter in high-salt wastewater after removal of alkalinity 6, nanofiltration device for pre-salt separation and purification of high-salt wastewater after removal of organic matter 7, concentration of high-salt wastewater on the nanofiltration product water side Concentrated electrodialysis device 8. A bipolar membrane electrodialysis device for acid-base production of high-concentration sodium chloride brine concentrated in nanofiltration water. 9. Evaporation and crystallization of sodium sulfate crystalline salt prepared from sodium sulfate brine in nanofiltration concentrated water device 10;

High-efficiency sedimentation tank device 1, high-efficiency filtration device 2, ultrafiltration device 3, ion exchange device 4, stripping device 5, and advanced catalytic oxidation device 6 are connected in sequence according to the treatment process of high-salt wastewater, and the water production side of nanofiltration device 7 is connected in sequence Concentration electrodialysis device 8, bipolar membrane electrodialysis device 9, and nanofiltration device 7 are connected to evaporation and crystallization device 10 on the concentrated water side.

Among them, the high-efficiency sedimentation tank device 1 is used to connect high-salt wastewater for softening pretreatment, and precipitate impurities such as calcium, magnesium, silicon, heavy metal ions, and larger suspended solids in high-salt wastewater to obtain primary treated water;

The high-efficiency filtration device 2 and the ultrafiltration device 3, the primary treated water passes through the high-efficiency filtration device 2 and the ultrafiltration device 3 successively, and the smaller suspended solids and colloids in the primary treated water are removed to obtain the secondary treated water;

The ion exchange device 4 is used to remove calcium, magnesium and heavy metals remaining in the secondary treatment water to obtain resin produced water;

The stripping device 5 is used to remove the alkalinity of the resin product water, adjust the pH value of the resin product water by adding hydrochloric acid, and remove the carbonate reaction therein, and then obtain the decarbonized product water;

The advanced catalytic oxidation device 6 is used to perform COD removal treatment and activated carbon adsorption treatment on the decarbonized produced water, remove organic impurities and chroma removal treatment in the decarbonized produced water, and obtain tertiary treated water;

The nanofiltration device 7 is used to separate and purify the tertiary treated water, and then generate the nanofiltration product water of the monovalent ion sodium chloride and the nanofiltration concentrated water mainly of the divalent ion sodium sulfate;

Concentration electrodialysis device 8 is used to receive nanofiltration product water, and high-fold concentration of nanofiltration product water to obtain high-concentration sodium chloride brine;

The bipolar membrane electrodialysis device 9 is used to electrolyze sodium chloride brine to obtain hydrochloric acid and liquid caustic soda; the hydrochloric acid and liquid caustic soda produced by the bipolar membrane electrodialysis device 9 are returned to the high-efficiency sedimentation tank 104 and blow-off device through pipelines 5 recycling.

The evaporation and crystallization device 10 is used to concentrate and crystallize nanofiltration concentrated sodium sulfate brine to obtain industrial grade sodium sulfate by using mechanical steam in a compression process or a multi-effect evaporation crystallization process. Finally, the effective separation and high-fold concentration of sodium chloride and sodium sulfate in high-salt wastewater are realized, and high-concentration sodium chloride and high-salt wastewater is used to produce higher value-added acid-base as the system's own chemical agent and reuse it in the front-end system. To achieve the deep resource utilization of high-salt wastewater and obtain products with high market value, and finally achieve the goal of zero discharge and resource treatment of high-salt wastewater.

In this embodiment, the high-efficiency sedimentation tank 104 device 1 includes a primary coagulation tank 101, a secondary coagulation tank 102, a flocculation tank 103, a sedimentation tank 104, a pH adjustment tank 105, and a sludge return pump, and the high-salt wastewater passes through the The primary coagulation tank 101, the secondary coagulation tank 102, the flocculation tank 103, and the sedimentation tank 104. The high-salt wastewater in the sedimentation tank 104 is stratified to form water phase and activated sludge, and the water phase enters the pH adjustment tank 105 to form a To treat water, the activated sludge returns to the primary coagulation tank 101 through the sludge return pump, so that the activated sludge circulates in the primary coagulation tank 101, the secondary coagulation tank 102, the flocculation tank 103, and the sedimentation tank 104. During the circulating flow of activated sludge in the primary coagulation tank 101, the secondary coagulation tank 102, the flocculation tank 103 and the sedimentation tank 104, the activated sludge can speed up the process of the primary coagulation tank 101, the secondary coagulation tank 102 and the flocculation tank. 103 The speed of reaction and flocculation.

In this embodiment, the liquid caustic soda produced by the bipolar membrane electrodialysis device 9 is added to the primary coagulation tank 101, sodium carbonate is added to the secondary coagulation tank 102, flocculant, auxiliary Coagulant, the hydrochloric acid produced by the bipolar membrane electrodialysis device 9 is added to the pH adjustment tank 105, and the hydrochloric acid and soda ash produced by the bipolar membrane electrodialysis device 9 are rationally utilized to maximize the deep resource utilization of high-salt wastewater and Obtain products with high market value, and finally achieve the goal of zero discharge and resource treatment of high-salt wastewater, thereby greatly reducing the treatment cost of high-salt wastewater.

In the present embodiment, the nanofiltration device 7 adopts a nanofiltration membrane with a sulfate radical rejection rate higher than 97%, and the sulfate radical content in the nanofiltration concentrated water is not less than 50000 mg/L, and passes through the nanofiltration membrane with a sulfate radical rejection rate higher than 97%. The filter membrane makes the separation of the monovalent ion sodium chloride and the divalent ion sodium sulfate in the nanofiltration device 7 more complete.

Preferably, the concentrated electrodialysis device 8 concentrates the brine of the nanofiltration product water to a TDS concentration of 150,000-200,000 mg/L to obtain high-concentration sodium chloride brine.

Preferably, the advanced catalytic oxidation device 6 includes an advanced catalytic oxidation tower and an activated carbon adsorption tower. 35% to 45%, and then effectively remove the organic matter and stains in the decarbonized product water.

As preferably, in the stripping device 5, the pH value of the resin product water is adjusted by adding hydrochloric acid, so that its pH value is between 4 and 6. It should be noted that the hydrochloric acid required in the stripping device 5 comes from bipolar membrane electrodialysis The device 9 reacts the hydrochloric acid produced by the bipolar membrane electrodialysis device 9 with the carbonate in the resin produced water to generate carbon dioxide and water, and finally blows the carbon dioxide out through the decarburization fan, thereby achieving the effect of decarburization and alkali removal of the resin produced water .

In this embodiment, the high-efficiency filter device 2 adopts a fiber filter material filter, and the turbidity of the effluent is ≤3NTU.

In this embodiment, the ion exchange device 4 is filled with resin, and the outlet water hardness is ≤5 mg/L.

In this embodiment, an evaporative crystallization device 10 is also included. The evaporative crystallization device 10 uses MVR evaporative crystallization or multi-effect evaporative crystallization technology to evaporate and crystallize nanofiltration concentrated water to produce anhydrous sodium sulfate, and recover anhydrous sulfuric acid with higher value Sodium products are sold as resources, and finally achieve the goal of zero discharge, resource treatment and recycling of high-salt wastewater.

More preferably, in the process of preparing anhydrous sodium sulfate in the evaporation and crystallization device 10, water vapor will also be produced. In the present invention, the water vapor is condensed and recovered, and then the deep resource utilization of high-salt wastewater is realized to the greatest extent. and obtain products with high market value, and finally realize the goal of zero discharge and resourceful treatment of high-salt wastewater; specifically, the evaporative crystallization device 10 is provided with an evaporative condensed water cooling device; the evaporative condensed water cooling device includes an evaporative raw water tank 11, Raw water pump 12, heat exchanger 13, condensed water tank 15, condensed water pump 14, evaporating crystallizer, reuse water pool 16; evaporating raw water tank 11 is connected to the inlet of evaporating raw water pump 12 through a raw water pipeline, heat exchanger 13 is refrigerant inlet The raw water inlet pipe is connected to the outlet of the evaporating raw water pump 12, the refrigerant outlet of the heat exchanger 13 is connected to the evaporation crystallizer through the raw water outlet pipe, and the heat medium inlet of the heat exchanger 13 is connected to the evaporating condensate pump through the condensed water inlet pipe 14 is connected to the outlet end, and the heat medium outlet end of the heat exchanger 13 is connected to the reuse water pool 16 through the condensed water outlet pipe.

More specifically, the raw water outlet pipe passes through the heat exchanger 13 and then branches off to a raw water return pipe to return to the evaporation raw water tank 11 to ensure a stable large flow of refrigerant during operation and the outlet temperature of the evaporative condensed water does not exceed the temperature.

The present invention also discloses a high-salt wastewater zero-discharge and resource-based treatment method, including:

Also disclosed is a zero-discharge and resource-based treatment method for high-salt wastewater, including:

S1. The high-efficiency sedimentation tank is connected to the high-salt wastewater for softening pretreatment, and precipitates impurities such as calcium, magnesium, silicon, heavy metal ions, and larger suspended solids in the high-salt wastewater to obtain primary treated water;

S2, the primary treatment water passes through the high-efficiency filtration device and the ultrafiltration device successively to remove the smaller suspended solids and colloids in the primary treatment water to obtain the secondary treatment water;

S3. Removing calcium, magnesium and heavy metals remaining in the secondary treatment water through an ion exchange device to obtain resin produced water;

S4. The stripping device performs alkalinity removal treatment on the resin product water, adjusts the pH value of the resin product water by adding hydrochloric acid, and removes the carbonate reaction therein, and then obtains the decarbonized product water;

S5. Perform COD removal treatment and activated carbon adsorption treatment on the decarbonized product water through the advanced catalytic oxidation device, remove organic impurities and chroma removal treatment in the decarbonized product water, and obtain tertiary treated water;

S6. Separating and purifying the water treated three times, and then generating nanofiltration product water of monovalent ion sodium chloride and nanofiltration concentrated water mainly of divalent ion sodium sulfate;

S7, high-fold concentration of nanofiltration product water to obtain high-concentration sodium chloride brine;

S8, electrolyzing sodium chloride brine to obtain hydrochloric acid and liquid caustic soda;

The hydrochloric acid and liquid caustic soda produced in S8 are returned to the high-efficiency sedimentation tank and the stripping device through pipelines for recycling.

As a preference, in S1, the high-efficiency wastewater passes through the primary coagulation tank, the secondary coagulation tank, the flocculation tank, the sedimentation tank, and the pH adjustment tank in sequence, and the high-salt wastewater in the sedimentation tank is stratified to form water phase and activated sludge. Phase enters the pH adjustment tank to form primary treatment water, and the activated sludge returns to the primary coagulation tank through the sludge return pump.

As preferably, the liquid caustic soda produced in step S8 is added to the primary coagulation tank described in S1, sodium carbonate is added to the secondary coagulation tank, flocculant and coagulant are added to the coagulation tank, and the pH is adjusted Add the hydrochloric acid produced in step S8 in the pool.

Preferably, in S5, the decarbonized product water passes through the advanced catalytic oxidation tower and the activated carbon adsorption tower in sequence, and the organic matter and chroma in the decarbonized product water are removed through the advanced catalytic oxidation tower and the activated carbon adsorption tower.

Preferably, it also includes S9, which is used for evaporating and crystallizing the nanofiltration concentrated water to produce anhydrous sodium sulfate through a crystallization device.

Embodiment effect is as follows:

(1) The high-salt wastewater produced by coal chemical wastewater industry, coal-fired power plant desulfurization wastewater industry, coal mine water industry, printing and dyeing wastewater industry, papermaking wastewater industry, etc. has complex water quality and large fluctuations. The settling tank device is used for softening treatment. In this embodiment, the concentration of calcium in the effluent is as low as 28 mg/L, the concentration of magnesium is as low as 7 mg/L, and the concentration of silicon is as low as 15 mg/L.

(2) The high-salt wastewater after softening treatment enters the fiber bundle filter device, and the effluent turbidity is 3NTU in this embodiment; the produced water enters the ultrafiltration device for further filtration;

(3) The filtered high-salt wastewater is transported to an ion exchange device to further remove calcium, magnesium, and heavy metal ions. In this embodiment, the total hardness of the effluent (in terms of calcium carbonate) is as low as 5 mg/L;

(4) Transport the resin produced water to the stripping device for alkalinity removal treatment. In this embodiment, the alkalinity of the decarburized produced water is 49 mg/L;

(5) Transport the decarbonized product water to an advanced catalytic oxidation device for COD and chroma removal treatment. In this embodiment, the removal rate of organic matter is 40%, and the effluent color is less than 10 degrees to obtain oxidized product water;

(6) Send the oxidized water to the nanofiltration device to separate and purify the brine, and use the selective permeability of the nanofiltration device 1 for different ions to divide the high-salt wastewater into the nanofiltration product water mainly composed of monovalent ions—— Sodium chloride containing brine, nanofiltration concentrated water based on divalent ions—sodium sulfate containing brine; the operating pressure of the membrane in this embodiment is about 34bar, and the recovery rate is 80%. The high-salt wastewater entering the nanofiltration device is mainly The water quality indicators are shown in the table below:

amount of water TDS Chloride Sulfate <![CDATA[m³/h]]> mg/L mg/L mg/L 100 65684 24670 11674

In the embodiment, the interception rate of the nanofiltration membrane to the sulfate radical is about 97%, and the interception rate to the chloride ion is about -0.6%, that is, after the high-salt wastewater passes through the nanofiltration device, the monovalent ion chloride ion is enriched and the divalent ion Only 3% of sulfate radicals permeated, and most of the sulfate radicals were trapped in the sodium sulfate brine on the concentrated water side of the nanofiltration. In this way, the high-efficiency separation of sodium sulfate and sodium chloride in high-salt wastewater was completed, and obtained Sodium sulfate and sodium chloride are two different ionic states of brine, and the main indicators of the two brines are shown in the following table:

(7) The sodium chloride-containing brine of the nanofiltration water is sent to the electrodialysis device for concentration enrichment to realize concentration reduction of high-salt wastewater. In this embodiment, the homogeneous ion exchange membrane selected for the concentration electrodialysis membrane group; in this embodiment, the amount of high-salt wastewater after passing through the concentration electrodialysis device is reduced from 80m ³ /h, TDS about 49900mg/L to about 10m ³ /h, 200000mg/L;

(8) The high-concentration sodium chloride brine is transported to the bipolar membrane electrodialysis concentration to obtain higher value-added hydrochloric acid and liquid caustic soda; The catalytic membrane converts the sodium chloride salt with a concentration of 200000mg/L into sodium hydroxide with a mass concentration of about 8% and hydrochloric acid with a mass concentration of about 7%;

(9) The nanofiltration concentrated water is transported to the MVR evaporation and crystallization device to obtain evaporation condensate meeting the reuse requirements and industrial-grade anhydrous sodium sulfate products. The quality of sodium sulfate crystalline salt meets the requirements of "GB/T6009-2014 Industrial Anhydrous Sodium Sulfate 》Class II first-class product standard (purity 98%);

(10) Further, the liquid caustic soda produced by bipolar membrane electrodialysis electrolysis is transported to the first-stage coagulation tank of the high-efficiency sedimentation tank and the evaporation crystallization device, and the obtained hydrochloric acid is transported to the pH adjustment tank, the stripping device, and the nanofiltration device.

The above disclosures are only a few specific embodiments of the present invention, but the present invention is not limited thereto, and any changes conceivable by those skilled in the art shall fall within the protection scope of the present invention.

Claims (10)

1. The utility model provides a high salt waste water zero release and resourceful processing system which characterized in that includes:

the efficient sedimentation tank device is used for introducing high-salinity wastewater to carry out softening pretreatment, and sedimentating impurities such as calcium, magnesium, silicon, heavy metal ions, larger suspended matters and the like in the high-salinity wastewater to obtain primary treated water;

the primary treated water sequentially passes through the high-efficiency filtering device and the ultrafiltration device, and small suspended matters and colloids in the primary treated water are removed to obtain secondary treated water;

the ion exchange device is used for removing calcium, magnesium and heavy metals in the secondary treatment water to obtain resin produced water;

the blowing-off device is used for carrying out alkalinity removal treatment on the resin produced water, adjusting the pH value of the resin produced water by adding hydrochloric acid, and removing carbonate in the resin produced water for reaction so as to obtain decarbonized produced water;

the advanced catalytic oxidation device is used for carrying out COD (chemical oxygen demand) removal treatment and activated carbon adsorption treatment on the decarbonized produced water, removing organic impurities and chromaticity in the decarbonized produced water and carrying out removal treatment to obtain tertiary treated water;

the nanofiltration device is used for separating and purifying the three times of treated water so as to generate nanofiltration produced water of monovalent ion sodium chloride and nanofiltration concentrated water mainly containing divalent ion sodium sulfate;

the concentration electrodialysis device is used for receiving the nanofiltration produced water and concentrating the nanofiltration produced water at high power to obtain high-concentration sodium chloride brine;

the bipolar membrane electrodialysis device is used for electrolyzing the sodium chloride saline to prepare hydrochloric acid and liquid caustic soda;

and hydrochloric acid and caustic soda liquid prepared by the bipolar membrane electrodialysis device flow back to the efficient sedimentation tank device and the stripping device through pipelines for recycling.

2. The high-salinity wastewater zero-discharge and resource treatment system according to claim 1, wherein the high-efficiency sedimentation tank device comprises a primary coagulation tank, a secondary coagulation tank, a flocculation tank, a sedimentation tank, a pH adjusting tank and a sludge reflux pump, the high-salinity wastewater sequentially passes through the primary coagulation tank, the secondary coagulation tank, the flocculation tank and the sedimentation tank, the high-salinity wastewater is layered in the sedimentation tank to form a water phase and activated sludge, the water phase enters the pH adjusting tank to form the primary treatment water, and the activated sludge is refluxed to the primary coagulation tank through the sludge reflux pump.

3. The high-salinity wastewater zero-discharge and recycling treatment system according to claim 2, wherein the first-stage coagulation tank is filled with liquid caustic soda produced by the bipolar membrane electrodialysis device, the second-stage coagulation tank is filled with sodium carbonate, the flocculation tank is filled with flocculating agent and coagulant aid, and the pH adjusting tank is filled with hydrochloric acid produced by the bipolar membrane electrodialysis device.

4. The high-salinity wastewater zero-discharge and recycling treatment system according to claim 1, characterized in that the advanced catalytic oxidation device comprises an advanced catalytic oxidation tower and an activated carbon adsorption tower, the decarbonized produced water sequentially passes through the advanced catalytic oxidation tower and the activated carbon adsorption tower, and the COD removal rate of the decarbonized produced water is 35-45% through the advanced catalytic oxidation tower and the activated carbon adsorption tower.

5. The high-salinity wastewater zero-discharge and resource treatment system according to claim 1, further comprising an evaporative crystallization device, wherein the evaporative crystallization device is used for evaporating and crystallizing the nanofiltration concentrated water to produce anhydrous sodium sulfate.

6. A high-salinity wastewater zero-discharge and resource treatment method is characterized by comprising the following steps:

s1, high-salinity wastewater is introduced into a high-efficiency sedimentation tank to be softened and pretreated, and impurities such as calcium, magnesium, silicon, heavy metal ions and larger suspended matters in the high-salinity wastewater are precipitated to obtain primary treated water;

s2, the primary treated water sequentially passes through a high-efficiency filtering device and an ultrafiltration device, and small suspended matters and colloids in the primary treated water are removed to obtain secondary treated water;

s3, removing residual calcium, magnesium and heavy metals in the secondary treatment water through an ion exchange device to obtain resin produced water;

s4, removing alkalinity of the resin produced water by using a blowing-off device, adjusting the pH value of the resin produced water by adding hydrochloric acid produced by the bipolar membrane electrodialysis device, and removing carbonate in the resin produced water for reaction to obtain decarbonized produced water;

s5, carrying out COD (chemical oxygen demand) removal treatment and activated carbon adsorption treatment on the decarbonized produced water through an advanced catalytic oxidation device, removing organic impurities and chromaticity in the decarbonized produced water, and obtaining third-time treated water;

s6, separating and purifying the three times of treated water to generate nanofiltration produced water of monovalent ion sodium chloride and nanofiltration concentrated water mainly containing divalent ion sodium sulfate;

s7, concentrating the nanofiltration produced water in a high-power manner to obtain high-concentration sodium chloride brine;

s8, electrolyzing the sodium chloride saline water to prepare hydrochloric acid and liquid caustic soda;

and (4) refluxing the hydrochloric acid and the liquid caustic soda prepared in the step (S8) to the high-efficiency sedimentation tank device and the stripping device through pipelines for recycling.

7. The high-salinity wastewater zero-discharge and resource treatment method according to claim 6, characterized in that in S1, high-efficiency wastewater sequentially passes through a primary coagulation tank, a secondary coagulation tank, a flocculation tank, a sedimentation tank and a pH adjusting tank, the high-salinity wastewater is layered in the sedimentation tank to form a water phase and activated sludge, the water phase enters the pH adjusting tank to form the primary treatment water, and the activated sludge flows back to the primary coagulation tank through a sludge reflux pump.

8. The method for zero discharge and resource treatment of high-salinity wastewater according to claim 7, characterized in that in S1, the liquid caustic soda produced in the step S8 is added into the primary coagulation tank, sodium carbonate is added into the secondary coagulation tank, a flocculating agent and a coagulant aid are added into the flocculation tank, and hydrochloric acid produced in the step S8 is added into the pH adjusting tank.

9. The method as claimed in claim 6, wherein in S5, the decarbonized water product is passed through an advanced catalytic oxidation tower and an activated carbon adsorption tower in sequence, and organic matters and color in the decarbonized water product are removed by the advanced catalytic oxidation tower and the activated carbon adsorption tower.

10. The high-salinity wastewater zero-discharge and recycling treatment method according to claim 6, further comprising S9, evaporating and crystallizing the nanofiltration concentrated water through a crystallization device to produce anhydrous sodium sulfate.

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