A chemical high-salinity wastewater advanced treatment system and treatment method

Abstract

The application discloses a kind of chemical high-salinity wastewater advanced treatment system and processing method, belong to wastewater treatment technical field.The application is sequentially connected by aeration micro-electrolysis cell, oxidation tank, electrodialysis device and bacteria-algae biochemical tank, so as to front " micro-electrolysis + two-stage oxidation " process, rear electrodialysis process and bacteria-algae biochemical degradation process;The application first utilizes aeration micro-electrolysis cell and oxidation tank to strengthen the degradation of organic pollutants, reduce the organic load of rear device, which is conducive to improving the degradation efficiency of subsequent treatment device to pollutants in wastewater;The application is strengthened by rear electrodialysis device, and the removal of organic pollutants in wastewater, while the acid and alkali generated in the process of electrodialysis can remove the residual anion introduced by front-end process simultaneously, effectively solve the problem of large subsequent sludge treatment amount or secondary pollution caused by oxidant addition;The application is rear bacteria-algae biochemical tank, which uses suspended bacteria-algae symbiotic granular sludge, can ensure the treatment effect of nitrogen and phosphorus in wastewater.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a deep treatment system and method for high-salt chemical wastewater. Background Technology

[0002] High-salinity wastewater typically refers to wastewater with a total salt content of at least 3.5 wt%. It is generated through a wide range of sources, such as chemical plants and oil and gas extraction and processing plants. This type of wastewater contains various pollutants, including salt, oil, organic heavy metals, and radioactive substances. With the continuous development of industrial production, the discharge of high-salinity wastewater is increasing year by year. Therefore, the treatment of high-salinity wastewater plays a crucial role in wastewater treatment, representing both a key focus and a challenge in wastewater treatment research.

[0003] Current research and commonly used methods for treating high-salinity wastewater are mainly constrained by factors such as high cost of physicochemical methods and large land area requirements of biological methods. For example, invention patent CN111252889A discloses a high-salinity wastewater treatment device and method combining algal symbiosis and membrane biofilm reactor. The device includes a membrane biofilm reactor, a gas separation membrane, an algal symbiotic biofilm, and a light source. The membrane biofilm reactor is a transparent cavity with an air inlet pipe and a water outlet pipe at the top and an air inlet pipe and an air outlet pipe at the bottom. The gas separation membrane is cast into a membrane module and placed inside the cavity, with the air inlet pipe and air outlet pipe connected to both ends of the module. An algal symbiotic biofilm grows on the surface of the gas separation membrane. The light source is located outside the cavity to uniformly irradiate the membrane biofilm reactor. This device mainly relies on a composite membrane system, which is prone to membrane fouling during wastewater treatment, resulting in high maintenance costs. Furthermore, high-salinity wastewater entering the membrane biofilm reactor without pretreatment severely affects the activity of algae and bacteria, leading to low treatment efficiency for pollutants in the wastewater.

[0004] Therefore, finding more efficient and faster technologies for treating high-salinity wastewater has become an urgent problem to be solved. Summary of the Invention

[0005] In view of the deficiencies of the existing technology, the purpose of this invention is to provide a deep treatment system and method for chemical high-salt wastewater.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a deep treatment system for high-salinity chemical wastewater, comprising an aerated micro-electrolysis tank, an oxidation tank, an electrodialysis device, and a bacterial and algal biochemical tank. The aerated micro-electrolysis tank contains a micro-electrolysis packing layer and a first aeration device. The inlet of the aerated micro-electrolysis tank is located above the micro-electrolysis packing layer, and the first aeration device and the outlet of the aerated micro-electrolysis tank are located below the micro-electrolysis packing layer. The outlet of the aerated micro-electrolysis tank is connected to the inlet of the oxidation tank via a pipe. The oxidation tank contains an ultraviolet lamp assembly. The ultraviolet lamp assembly is located between the inlet and outlet of the oxidation tank. The outlet of the oxidation tank is connected to the electrodialysis device via a pipe. The wastewater outlet of the electrodialysis device is connected to the inlet of the algae-bacterial biochemical tank via a pipe. The algae-bacterial biochemical tank has an algae-bacterial biochemical zone. From top to bottom, the algae-bacterial biochemical zone is provided with a suspended algae-bacterial granular sludge layer, a interception net, and a second aeration device. The inlet of the algae-bacterial biochemical tank is located above the suspended algae-bacterial granular sludge layer, and the outlet of the algae-bacterial biochemical tank is located below the interception net.

[0008] This invention utilizes a pre-process of "micro-electrolysis + two-stage oxidation" and a post-process of electrodialysis and biochemical degradation of bacteria and algae, by sequentially connecting an aerated micro-electrolysis tank, an oxidation tank, an electrodialysis device, and a bacterial and algal biochemical tank.

[0009] This invention first utilizes an aerated micro-electrolysis tank and an oxidation tank to construct a combined micro-electrolysis and ultraviolet Fenton oxidation technology, which can increase the production of high-energy ions in the system, enhance the degradation of organic pollutants, reduce the organic load of downstream devices, and thus improve the system's degradation efficiency for recalcitrant pollutants in high-salt wastewater.

[0010] This invention uses a post-electrodialysis device to enhance the removal of organic pollutants from wastewater. At the same time, the acids and alkalis generated during the electrodialysis process can simultaneously remove residual anions introduced by the upstream process, effectively solving the problem of large amounts of sludge or secondary pollution caused by the addition of oxidants.

[0011] The post-construction bacterial-algae biochemical tank of this invention uses suspended bacterial-algae symbiotic granular sludge. Compared with existing immobilized sludge, the granular sludge used in this invention has greater fluidity, ensuring uniform distribution of light and carbon sources in the bacterial-algae system. This is beneficial for maintaining good growth of bacteria and algae, enhancing the biochemical synergistic effect of microalgae and sludge bacteria, and thus ensuring the nitrogen and phosphorus treatment effect in wastewater.

[0012] In a preferred embodiment of the present invention, the micro-electrolysis filler layer includes two layers of screens, with coal slag micro-electrolysis balls disposed between the two layers of screens.

[0013] In a preferred embodiment of the present invention, the oxidation tank is equipped with a dosing device for adding an oxidant to the oxidation tank.

[0014] In a preferred embodiment of the present invention, the electrodialysis device includes an electrodialysis tank, in which a first bipolar membrane, an anion exchange membrane, a cation exchange membrane, and a second bipolar membrane are sequentially arranged. The first bipolar membrane, the anion exchange membrane, the cation exchange membrane, and the second bipolar membrane are separated into an anode zone, an acid production zone, a wastewater zone, an alkaline water zone, and a cathode zone sequentially arranged within the electrodialysis tank. An acid collection tank is connected below the acid production zone, a wastewater collection tank is connected below the wastewater zone, and an alkaline water collection tank is connected below the alkaline water zone. A first electrode is arranged in the anode zone, and a second electrode is arranged in the cathode zone. The first electrode is connected to the positive terminal of a power supply via a wire, and the second electrode is connected to the negative terminal of a power supply via a wire. The inlet of the electrodialysis device is located at the upper part of the wastewater zone, and the outlet of the electrodialysis device is located at the bottom of the wastewater collection tank.

[0015] Furthermore, the first bipolar membrane includes an anion exchange layer, a transition layer, and a cation exchange layer stacked sequentially, with the anion exchange layer of the first bipolar membrane facing the anode region and the cation exchange layer of the first bipolar membrane facing the acid-producing region.

[0016] Furthermore, the second bipolar membrane has the same structure as the first bipolar membrane, with the anion exchange layer of the second bipolar membrane facing the alkaline water region and the cation exchange layer of the second bipolar membrane facing the cathode region.

[0017] In a preferred embodiment of the present invention, the amount of activated sludge added to the suspended algae granular sludge layer is 15-20 g / L, and the amount of algae inoculation is 4-7 mL / L.

[0018] Secondly, the present invention provides a method for deep treatment of high-salinity chemical wastewater, which is implemented by the high-salinity chemical wastewater deep treatment system as described in the first aspect.

[0019] As a preferred embodiment of the present invention, the method for deep treatment of high-salinity chemical wastewater includes the following steps:

[0020] S1. Wastewater is fed into an aerated micro-electrolysis tank for aerated micro-electrolysis treatment.

[0021] S2. The wastewater treated in step S1 is fed into an oxidation tank for photocatalytic oxidation treatment.

[0022] S3. Input the wastewater treated in step S2 into the electrodialysis device for electrodialysis treatment;

[0023] S4. The wastewater treated in step S3 is fed into the algae and bacteria biochemical tank for degradation treatment, and then discharged.

[0024] Furthermore, step S2 also includes adding an oxidant during the photocatalytic treatment process, wherein the amount of oxidant added is 2-4 g / L.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) This invention uses an aerated micro-electrolysis tank, an oxidation tank, an electrodialysis device, and a bacterial and algal biochemical tank connected in sequence to perform a "micro-electrolysis + two-stage oxidation" process before the electrodialysis process and the bacterial and algal biochemical degradation process after the process. This invention first uses the aerated micro-electrolysis tank and the oxidation tank to enhance the degradation of organic pollutants, reduce the organic load of the downstream device, and improve the degradation efficiency of pollutants in wastewater by the downstream treatment device. This invention enhances the removal of organic pollutants in wastewater through the downstream electrodialysis device. At the same time, the acid and alkali generated during the electrodialysis process can simultaneously remove the residual anions introduced by the upstream process, effectively solving the problem of large amount of sludge treatment or secondary pollution caused by the addition of oxidant.

[0027] (2) The post-bacterial and algal biochemical tank of the present invention uses suspended granular sludge of bacterial and algal symbiosis. Compared with the existing immobilized sludge, the granular sludge used in the present invention has greater fluidity, which ensures that the light and carbon source are evenly distributed in the bacterial and algal system, which is conducive to maintaining the good growth state of bacteria and algae, enhancing the biochemical synergistic effect of microalgae and sludge bacteria, thereby ensuring the nitrogen and phosphorus treatment effect in wastewater. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the advanced treatment system for high-salt chemical wastewater provided by the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the electrodialysis device provided by the present invention;

[0030] Figure 3 A schematic diagram of the structure of the first bipolar membrane provided by the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of the bacterial and algal biochemical pool provided by the present invention.

[0032] In the diagram, 1-aerated micro-electrolysis cell, 11-micro-electrolysis packing layer, 12-first aeration device, 2-oxidation tank, 3-electrodialysis device, 31-electrodialysis cell, 311-anode zone, 312-acid production zone, 313-wastewater zone, 314-alkaline water zone, 315-cathode zone, 316-acid collection tank, 317-wastewater collection tank, 318-alkaline water collection tank, 32-first bipolar membrane, 321-anion exchange layer. 322-Transition layer, 323-Cation exchange layer, 33-Cation exchange membrane, 34-Anion exchange membrane, 35-Second bipolar membrane, 36-First electrode, 37-Second electrode, 4-Bacterial and algae biological treatment tank, 41-Water distribution trough, 42-Suspended bacterial and algae granular sludge layer, 43-Interception net, 44-Second aeration device, 45-Drainage trough, 46-Baffle plate, 47-Constant temperature and light system, 5-Dosing device, 6-Power supply. Detailed Implementation

[0033] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are commonly used reagents and instruments.

[0034] Please see Figure 1-4 This invention provides a deep treatment system for high-salinity chemical wastewater, comprising an aerated micro-electrolysis tank 1, an oxidation tank 2, an electrodialysis device 3, and a bacterial and algal biochemical tank 4. The aerated micro-electrolysis tank 1 is equipped with a micro-electrolysis packing layer 11 and a first aeration device 12. The inlet of the aerated micro-electrolysis tank 1 is located above the micro-electrolysis packing layer 11, and the outlet of the aerated micro-electrolysis tank 1 and the first aeration device 12 are located below the micro-electrolysis packing layer 11. The outlet of the aerated micro-electrolysis tank 1 is connected to the inlet of the oxidation tank 2 via a pipe. An ultraviolet lamp assembly is installed in the oxidation tank 2. The ultraviolet lamp assembly is located between the inlet and outlet of the oxidation tank 2. The outlet of the oxidation tank 2 is connected to the electrodialysis device 3 via a pipe. The wastewater outlet of the electrodialysis device 3 is connected to the inlet of the algae-bacterial biochemical tank 4 via a pipe. The algae-bacterial biochemical tank 4 has an algae-bacterial biochemical zone. The algae-bacterial biochemical zone is provided with a suspended algae-bacterial granular sludge layer 42, a interception net 43, and a second aeration device 44 from top to bottom. The inlet of the algae-bacterial biochemical tank 4 is located above the suspended algae-bacterial granular sludge layer 42, and the outlet of the algae-bacterial biochemical tank 4 is located below the interception net 43.

[0035] The present invention uses an aerated micro-electrolysis tank 1, an oxidation tank 2, an electrodialysis device 3, and a bacterial and algal biochemical tank 4 connected in sequence to perform a "micro-electrolysis + two-stage oxidation" process before the electrodialysis process and a bacterial and algal biochemical degradation process after the process.

[0036] This invention first utilizes an aerated micro-electrolysis cell 1 and an oxidation cell 2 to construct a combined micro-electrolysis and ultraviolet Fenton oxidation technology, which can increase the production of high-energy ions in the system, enhance the degradation of organic pollutants, reduce the organic load of downstream devices, and thus improve the system's degradation efficiency for recalcitrant pollutants in high-salt wastewater.

[0037] This invention, through the post-electrodialysis device 3, can enhance the removal of organic pollutants in wastewater. At the same time, the acids and alkalis generated during the electrodialysis process can simultaneously remove residual anions introduced by the front-end process, effectively solving the problem of large subsequent sludge treatment volume or secondary pollution caused by the addition of oxidants.

[0038] The post-construction bacterial-algae biochemical tank 4 of this invention uses suspended bacterial-algae symbiotic granular sludge. Compared with existing immobilized sludge, the granular sludge used in this invention has greater fluidity, ensuring uniform distribution of light and carbon sources in the bacterial-algae system. This is beneficial for maintaining good growth of bacteria and algae, enhancing the biochemical synergistic effect of microalgae and sludge bacteria, and thus ensuring the nitrogen and phosphorus treatment effect in wastewater.

[0039] In one embodiment, the micro-electrolysis packing layer 11 includes two layers of screens, with coal slag micro-electrolysis balls disposed between the two layers of screens. The particle size of the coal slag micro-electrolysis balls is 4-6 mm; the pore size of the screens is 2-3 mm.

[0040] Specifically, the coal slag micro-electrolysis ball includes the following raw material components: coal slag, iron powder and binder. The mass ratio of coal slag to iron powder is (0.5-2):1. The binder accounts for 10-30% of the raw materials of the coal slag micro-electrolysis ball. The coal slag is 80-200 mesh industrial gasification coal slag, and the particle size of the iron powder is 80-200 mesh.

[0041] Specifically, the preparation method of coal slag micro-electrolysis balls includes the following steps: coal slag, iron powder and binder are mixed, deionized water is added for adjustment, granulation is carried out and dried, and then calcined under a protective atmosphere and cooled to obtain coal slag micro-electrolysis balls.

[0042] The protective atmosphere includes at least one of nitrogen, helium, and argon.

[0043] During the roasting process, the temperature is first increased to 700-900℃ at a rate of 10-20℃ / min, and then roasted at 700-900℃ for 40-80 minutes.

[0044] This invention utilizes coal slag micro-electrolysis spheres. Coal slag has a high carbon content, and the sphere structure has a larger contact area with wastewater pollutants, resulting in higher micro-electrolysis reaction efficiency and improved micro-electrolysis performance.

[0045] In one embodiment, the oxidation tank 2 is equipped with a dosing device 5, which is used to add oxidant to the oxidation tank 2.

[0046] Specifically, the oxidizing agent includes at least one of potassium perchlorate and potassium permanganate.

[0047] After activation by ultraviolet light, the oxidant generates strong oxidizing particles such as anions and hydroxyl radicals. The wastewater then enters oxidation tank 2, where organic pollutants react with these strong oxidizing particles, further removing the organic pollutants. The dosing device 5 can be connected to the pipeline between oxidation tank 2 and aerated micro-electrolysis tank 1, facilitating the flow of the oxidant into oxidation tank 2 along with the wastewater.

[0048] In one embodiment, the electrodialysis device 3 includes an electrodialysis cell 31. A first bipolar membrane 32, an anion exchange membrane 34, a cation exchange membrane 33, and a second bipolar membrane 35 are sequentially arranged within the electrodialysis cell 31. The first bipolar membrane 32, anion exchange membrane 34, cation exchange membrane 33, and second bipolar membrane 35 divide the electrodialysis cell 31 into a sequentially arranged anode zone 311, an acid-producing zone 312, a wastewater zone 313, an alkaline water zone 314, and a cathode zone 315. An acid collection device is connected below the acid-producing zone 312. The wastewater collection tank 317 is connected below the wastewater zone 313, and the alkaline solution collection tank 318 is connected below the alkaline solution zone 314. A first electrode 36 is installed in the anode zone 311, and a second electrode 37 is installed in the cathode zone 315. The first electrode 36 is connected to the positive terminal of the power supply 6 through a wire, and the second electrode 37 is connected to the negative terminal of the power supply 6 through a wire. The inlet of the electrodialysis device 3 is located at the top of the wastewater zone 313, and the outlet of the electrodialysis device 3 is located at the bottom of the wastewater collection tank 317.

[0049] Specifically, the anode region 311 and the cathode region 315 are respectively filled with sodium hydroxide solution, and the mass fraction of sodium hydroxide in the sodium hydroxide solution is 2-5%.

[0050] Specifically, the rated voltage of power supply 6 is 30-40V, and the rated current is 4-5A.

[0051] Specifically, the first bipolar membrane 32 includes an anion exchange layer 321, a transition layer 322 and a cation exchange layer 323 stacked sequentially. The anion exchange layer 321 of the first bipolar membrane 32 faces the anode region 311, and the cation exchange layer 323 of the first bipolar membrane 32 faces the acid-producing region 312.

[0052] Specifically, the second bipolar membrane 35 has the same structure as the first bipolar membrane 32. The anion exchange layer of the second bipolar membrane 35 faces the alkaline water region 314, and the cation exchange layer of the second bipolar membrane 35 faces the cathode region 315.

[0053] In this invention, the cation exchange layer is a cation exchange membrane, the anion exchange layer is an anion exchange membrane, and the transition layer is a polytetrafluoroethylene membrane.

[0054] Specifically, both the first electrode 36 and the second electrode 37 are platinum electrodes.

[0055] In this invention, after energization, hydrogen ions are generated in the anode region 311 and hydroxide ions are generated in the cathode region 315. The hydrogen ions generated in the anode region 311 can pass through the first bipolar membrane 32 into the acid-producing region 312, and the hydroxide ions generated in the cathode region 315 can pass through the second bipolar membrane 35 into the alkaline water region 314. After the wastewater enters the wastewater region 313 of the electrodialysis device 3, the anions in the wastewater pass through the anion exchange membrane 34 into the acid-producing region 312 and mix with the hydrogen ions to form an acid solution. The cations in the wastewater pass through the cation exchange membrane 33 into the alkaline water region 314 and mix with the hydroxide ions to form an alkaline solution. The electrodialysis device 3 with its specific structure of this invention can effectively separate salts from high-salinity wastewater and simultaneously produce acid and alkaline solutions.

[0056] In one embodiment, the suspended algae and bacteria granular sludge layer 42 is formed by suspending algae and bacteria granular sludge in wastewater. The preparation method of the algae and bacteria granular sludge includes the following steps: inoculating activated sludge and algae agent into water in sequence, adding a carbon source and mixing, and culturing under light conditions for 60-90 days to obtain algae and bacteria granular sludge suspended in water; the carbon source is composed of glucose and anhydrous sodium acetate in a mass ratio of (5-10):1, the mass ratio of the carbon source to the volume of water is 3-8 g / L, the mass ratio of activated sludge to the volume of water in the suspended algae and bacteria granular sludge layer 42 is 15-20 g / L, and the volume ratio of algae agent to water is 4-7 mL / L.

[0057] In one embodiment, the algae and bacteria biochemical tank 4 is equipped with a constant temperature and light system 47. The algae and bacteria biochemical tank 4 is provided with a water distribution trough 41 and a drainage trough 45. Both the water distribution trough 41 and the drainage trough 45 have upward openings. The water distribution trough 41 is located between the water inlet of the algae and bacteria biochemical tank 4 and the algae and bacteria biochemical zone. The bottom of the water distribution trough 41 is provided with a number of water distribution holes that communicate with the algae and bacteria biochemical zone. The drainage trough 45 is located below the algae and bacteria biochemical zone and communicates with the water outlet of the algae and bacteria biochemical tank 4.

[0058] Specifically, the bacterial and algal biochemical pool 4 is equipped with several partitions 46, which are located between the water distribution trough 41 and the drainage trough 45. The partitions 46 divide the internal space of the bacterial and algal biochemical pool 4 into several bacterial and algal biochemical zones, and two adjacent bacterial and algal biochemical zones are connected through the drainage trough 45.

[0059] The present invention provides temperature and light conditions for the stable growth of bacteria and algae through a constant temperature and light system 47, and aeration through a second aeration device 44 to improve the degradation efficiency of microalgae and functional bacteria in sludge. Only after the wastewater is treated by the bacteria and algae biochemical pond 4 can it be discharged from the drainage trough 45 and the outlet.

[0060] In this invention, the aeration direction of the first aeration device 12 and the second aeration device 44 is both upward, opposite to the direction of water flow, which is conducive to stable aeration and improves the wastewater treatment efficiency of the system.

[0061] In this invention, each pipeline is equipped with a control valve.

[0062] The present invention provides a method for deep treatment of high-salinity chemical wastewater, which is implemented through the aforementioned high-salinity chemical wastewater deep treatment system.

[0063] In one embodiment, the deep treatment method for high-salinity chemical wastewater includes the following steps:

[0064] S1. The wastewater is fed into the aerated micro-electrolysis tank 1 for aerated micro-electrolysis treatment;

[0065] S2. The wastewater treated in step S1 is fed into oxidation tank 2 for photocatalytic oxidation treatment;

[0066] S3. Input the wastewater treated in step S2 into the electrodialysis device 3 for electrodialysis treatment;

[0067] S4. The wastewater treated in step S3 is fed into the algae and bacteria biochemical tank 4 for degradation treatment, and then discharged.

[0068] Specifically, in step S1, the aeration rate of the aeration micro-electrolysis treatment is 0.8-1 L / min, and the time (i.e., the hydraulic retention time in step S1) is 30-60 min. In step S1, the dosage of the coal slag micro-electrolysis balls is 30-50 g / L.

[0069] In this invention, the amount of coal slag micro-electrolysis balls added is the ratio between the mass (g) of the coal slag micro-electrolysis balls and the product of the input wastewater flow rate (L / min) and hydraulic retention time (min) in step S1.

[0070] Specifically, in step S2, during photocatalytic oxidation, an oxidant is added at a dosage of 2-4 g / L, and the pH of the wastewater is controlled at 5-8. The power of the ultraviolet lamp is controlled at 40-60 W, and the light intensity is controlled at 60-70 mW / cm². 2 The time for photocatalytic oxidation treatment (i.e., the hydraulic residence time in step S2) is 1.5-2 hours.

[0071] In this invention, the amount of oxidant added refers to the ratio between the mass (g) of the oxidant and the product of the input wastewater flow rate (L / min) and the hydraulic retention time (min) in step S2.

[0072] Specifically, in step S3, the voltage of the electrodialysis treatment is 30-40V, the current is 4-5A, and the time (i.e., the hydraulic retention time in step S3) is 40-80min.

[0073] Specifically, in step S4, the aeration rate for the degradation treatment is 1.5-2 L / min, and the time (i.e., the hydraulic retention time in step S4) is 3-4 h.

[0074] The present invention provides the following embodiments to facilitate understanding of the invention. These embodiments are provided not to limit the scope of the claims.

[0075] In the following examples, the algae agent is GY-H20 cloud microalgae from Shanghai Biotechnology Co., Ltd.

[0076] The wastewater conditions in the following examples are: COD content 25000±230 mg / L, Cl... - The content was 90±2.5 mg / L, NH4 + The content of -N was 330±11 mg / L, the content of TN (total nitrogen) was 410±17 mg / L, and the content of TP (total phosphorus) was 80±2.4 mg / L.

[0077] The suspended algae and bacteria granular sludge layer 42 described below is formed by suspending algae and bacteria granular sludge in water. The preparation method of the algae and bacteria granular sludge includes the following steps: inoculating activated sludge and algae agent into water in sequence, adding carbon source and mixing, and culturing under light conditions for 75 days to obtain algae and bacteria granular sludge suspended in water; the carbon source is composed of glucose and anhydrous sodium acetate in a mass ratio of 8:1, the mass ratio of the carbon source to the volume of water is 5 g / L, the mass ratio of the activated sludge to the volume of water is 20 g / L, and the volume ratio of the algae agent to the water is 7 mL / L.

[0078] Examples 1-11

[0079] An embodiment of the advanced treatment system and method for high-salinity chemical wastewater according to the present invention is shown below. The structure of the advanced treatment system for high-salinity chemical wastewater is as follows: Figure 1-4 As shown, it includes an aerated micro-electrolysis cell 1, an oxidation cell 2, an electrodialysis device 3, and a bacterial and algal biochemical cell 4.

[0080] The aerated micro-electrolysis tank 1 is equipped with a micro-electrolysis packing layer 11 and a first aeration device 12. The inlet of the aerated micro-electrolysis tank 1 is located above the micro-electrolysis packing layer 11, and the first aeration device 12 and the outlet of the aerated micro-electrolysis tank 1 are located below the micro-electrolysis packing layer 11. The outlet of the aerated micro-electrolysis tank 1 is connected to the inlet of the oxidation tank 2 through a pipe. The micro-electrolysis filler layer 11 includes two layers of sieves, with coal slag micro-electrolysis balls placed between the two layers of sieves; the dosage of coal slag micro-electrolysis balls is shown in Table 1; the particle size of the coal slag micro-electrolysis balls is 5 mm; the sieve aperture is 3 mm; the coal slag micro-electrolysis balls include the following raw material components: coal slag, iron powder and binder, with a mass ratio of coal slag to iron powder of 1:1, and the binder accounting for 20% of the raw materials of the coal slag micro-electrolysis balls; the coal slag is 100 mesh industrial gasification coal slag, and the iron powder has a particle size of 100 mesh; the preparation method of the coal slag micro-electrolysis balls includes the following steps: after mixing the coal slag, iron powder and binder, deionized water is added for adjustment, granulation is performed, drying is carried out, and then calcination is performed under a nitrogen atmosphere. During calcination, the temperature is first raised to 800℃ at a heating rate of 15℃ / min, and calcined at 800℃ for 60 min; finally, it is naturally cooled to room temperature to obtain the coal slag micro-electrolysis balls.

[0081] An ultraviolet lamp assembly is installed inside oxidation tank 2, located between the inlet and outlet of oxidation tank 2. The outlet of oxidation tank 2 is connected to the electrodialysis device 3 via a pipe. Oxidation tank 2 is equipped with a dosing device 5, which is used to add an oxidant, potassium perchlorate, to oxidation tank 2.

[0082] The electrodialysis device 3 includes an electrodialysis cell 31. A first bipolar membrane 32, an anion exchange membrane 34, a cation exchange membrane 33, and a second bipolar membrane 35 are sequentially arranged within the electrodialysis cell 31. The first bipolar membrane 32, anion exchange membrane 34, cation exchange membrane 33, and second bipolar membrane 35 divide the electrodialysis cell 31 into an anode zone 311, an acid-producing zone 312, a wastewater zone 313, an alkaline zone 314, and a cathode zone 315, arranged sequentially. An acid-producing zone 312 is connected to an acid collection tank 316 below it, a wastewater zone 313 is connected to a wastewater collection tank 317 below it, and an alkaline zone 314 is connected to an alkaline collection tank 318 below it. A first electrode 36 is arranged in the anode zone 311, and a second electrode 37 is arranged in the cathode zone 315. The first electrode 36 is connected to the positive terminal of a power supply 6 via a wire, and the second electrode 37 is connected to the negative terminal of the power supply 6 via a wire. The inlet is located at the top of the wastewater zone 313, and the outlet of the electrodialysis device 3 is located at the bottom of the wastewater collection tank 317. The anode zone 311 and the cathode zone 315 are respectively filled with sodium hydroxide solution, and the mass fraction of sodium hydroxide in the sodium hydroxide solution is 4%. The rated power supply 6 is 35V and the rated current is 4.4A. The first bipolar membrane 32 includes anion exchange layer 321, transition layer 322 and cation exchange layer 323 stacked in sequence. The anion exchange layer 321 of the first bipolar membrane 32 faces the anode zone 311, and the cation exchange layer 323 of the first bipolar membrane 32 faces the acid production zone 312. The second bipolar membrane 35 has the same structure as the first bipolar membrane 32. The anion exchange layer of the second bipolar membrane 35 faces the alkaline water zone 314, and the cation exchange layer of the second bipolar membrane 35 faces the cathode zone 315. The first electrode 36 and the second electrode 37 are both platinum electrodes.

[0083] The wastewater outlet of the electrodialysis device 3 is connected to the inlet of the algae-bacterial biochemical tank 4 via a pipe. The algae-bacterial biochemical tank 4 has an algae-bacterial biochemical zone, which, from top to bottom, consists of a suspended algae-bacterial granular sludge layer 42, a retaining net 43, and a second aeration device 44. The inlet of the algae-bacterial biochemical tank 4 is located above the suspended algae-bacterial granular sludge layer 42, and the outlet of the algae-bacterial biochemical tank 4 is located below the retaining net 43. The algae-bacterial biochemical tank 4 is equipped with a constant temperature and light system 47. The algae-bacterial biochemical tank 4 contains a water distribution trough 41 and a drainage trough 45. All 5 have upward openings; the water distribution trough 41 is located between the inlet of the algae and bacteria biochemical pool 4 and the algae and bacteria biochemical zone, and the bottom of the water distribution trough 41 is provided with several water distribution holes that communicate with the algae and bacteria biochemical zone; the drainage trough 45 is located below the algae and bacteria biochemical zone, and the drainage trough 45 communicates with the outlet of the algae and bacteria biochemical pool 4; several partitions 46 are provided inside the algae and bacteria biochemical pool 4, and the partitions 46 are located between the water distribution trough 41 and the drainage trough 45. The partitions 46 divide the internal space of the algae and bacteria biochemical pool 4 into several algae and bacteria biochemical zones, and two adjacent algae and bacteria biochemical zones are connected through the drainage trough 45.

[0084] The treatment method is implemented through a deep treatment system for high-salinity chemical wastewater, and includes the following steps:

[0085] S1. The wastewater is fed into the aerated micro-electrolysis tank 1 for aerated micro-electrolysis treatment;

[0086] S2. The wastewater treated in step S1 is fed into oxidation tank 2 for photocatalytic oxidation treatment;

[0087] S3. Input the wastewater treated in step S2 into the electrodialysis device 3 for electrodialysis treatment;

[0088] S4. The wastewater treated in step S3 is fed into the algae and bacteria biochemical tank 4 for degradation treatment, and then discharged.

[0089] In step S1, the aeration rate of the micro-electrolysis treatment is 1 L / min, and the time is 60 min.

[0090] In step S2, during photocatalytic oxidation, an oxidant is added. The dosage of the oxidant is shown in Table 1. The pH value of the wastewater is also shown in Table 1. The power of the ultraviolet lamp is controlled at 50W, and the light intensity is controlled at 65mW / cm². 2 The photocatalytic oxidation treatment time was 2 hours.

[0091] In step S3, the voltage of the electrodialysis treatment is 35V, the current is 4.4A, and the time is 60min.

[0092] In step S4, the aeration rate for the degradation treatment is 2 L / min, and the time is 3.5 h.

[0093] The changes in COD, ammonia nitrogen, and total phosphorus in wastewater after treatment in step S4 of each embodiment were determined using a multi-parameter rapid water quality analyzer. The test method is as follows: 2 mL of the water sample to be tested was added to the COD, ammonia nitrogen, and total phosphorus pretreatment agents respectively and mixed evenly. Three sets of samples were taken for each indicator for testing. The samples were placed in digesters for digestion at a temperature of 150℃ for 120 min. After digestion, the digestion tubes were removed and cooled to room temperature before being measured using a multi-parameter rapid water quality analyzer.

[0094] Table 1

[0095]

[0096] As shown in Table 1, the advanced treatment system for high-salt chemical wastewater described in this invention can effectively remove pollutants from wastewater, achieving COD removal rates of ≥53%, ammonia nitrogen removal rates of ≥65%, total phosphorus removal rates of ≥63%, and total nitrogen removal rates of ≥64%. This invention controls the dosage of coal slag micro-electrolysis balls at 40-45 g / L, the dosage of oxidant at 4-5 g / L, and the pH value at 6-7, resulting in even better wastewater treatment performance.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A deep treatment system for high-salinity chemical wastewater, characterized in that, The system includes an aerated micro-electrolysis tank, an oxidation tank, an electrodialysis device, and a bacterial and algal biochemical tank. The aerated micro-electrolysis tank contains a micro-electrolysis packing layer and a first aeration device. The inlet of the aerated micro-electrolysis tank is located above the micro-electrolysis packing layer, while the first aeration device and the outlet of the aerated micro-electrolysis tank are located below the packing layer. The outlet of the aerated micro-electrolysis tank is connected to the inlet of the oxidation tank via a pipe. The oxidation tank contains an ultraviolet lamp assembly located within the oxidation tank. The inlet of the tank is connected to the outlet of the oxidation tank, and the outlet of the oxidation tank is connected to the electrodialysis device through a pipe; the wastewater outlet of the electrodialysis device is connected to the inlet of the bacterial and algal biochemical tank through a pipe. The bacterial and algal biochemical tank has a bacterial and algal biochemical zone, which is provided with a suspended bacterial and algal granular sludge layer, a interception net and a second aeration device from top to bottom. The inlet of the bacterial and algal biochemical tank is located above the suspended bacterial and algal granular sludge layer, and the outlet of the bacterial and algal biochemical tank is located below the interception net. The oxidation tank is equipped with a dosing device for adding an oxidant to the oxidation tank. The oxidant includes at least one of potassium perchlorate and potassium permanganate. The bacterial and algal biochemical pool is equipped with a constant temperature and light system; The suspended bacterial and algae granular sludge layer is formed by suspending bacterial and algae granular sludge in wastewater; The preparation method of the bacterial and algal granular sludge includes the following steps: activated sludge and algae agent are sequentially inoculated into water, and a carbon source is added and mixed. Under light conditions, the mixture is cultured for 60-90 days to obtain bacterial and algal granular sludge suspended in water. The carbon source is composed of glucose and anhydrous sodium acetate in a mass ratio of (5-10):

1. The mass ratio of the carbon source to the volume of water is 3-8 g / L, the mass ratio of the activated sludge to the volume of water is 15-20 g / L, and the volume ratio of the algae agent to the water is 4-7 mL / L.

2. The advanced treatment system for high-salinity chemical wastewater as described in claim 1, characterized in that, The micro-electrolysis filler layer includes two layers of screens, with coal slag micro-electrolysis balls disposed between the two layers of screens.

3. The advanced treatment system for high-salinity chemical wastewater as described in claim 1, characterized in that, The electrodialysis device includes an electrodialysis tank, in which a first bipolar membrane, an anion exchange membrane, a cation exchange membrane, and a second bipolar membrane are sequentially arranged. The first bipolar membrane, anion exchange membrane, cation exchange membrane, and second bipolar membrane divide the electrodialysis tank into an anode zone, an acid-producing zone, a wastewater zone, an alkaline zone, and a cathode zone, arranged sequentially. An acid-producing zone is connected to an acid collection tank below it, a wastewater zone is connected to a wastewater collection tank below it, and an alkaline zone is connected to an alkaline collection tank below it. A first electrode is arranged in the anode zone, and a second electrode is arranged in the cathode zone. The first electrode is connected to the positive terminal of a power source via a wire, and the second electrode is connected to the negative terminal of a power source via a wire. The inlet of the electrodialysis device is located at the upper part of the wastewater zone, and the outlet of the electrodialysis device is located at the bottom of the wastewater collection tank.

4. The advanced treatment system for high-salinity chemical wastewater as described in claim 3, characterized in that, The first bipolar membrane includes an anion exchange layer, a transition layer and a cation exchange layer stacked sequentially, with the anion exchange layer of the first bipolar membrane facing the anode region and the cation exchange layer of the first bipolar membrane facing the acid-producing region.

5. The advanced treatment system for high-salinity chemical wastewater as described in claim 3, characterized in that, The second bipolar membrane has the same structure as the first bipolar membrane, with the anion exchange layer of the second bipolar membrane facing the alkaline water region and the cation exchange layer of the second bipolar membrane facing the cathode region.

6. A method for deep treatment of high-salinity chemical wastewater, characterized in that, This is implemented using the advanced treatment system for high-salinity chemical wastewater as described in any one of claims 1-5.

7. The method for deep treatment of high-salinity chemical wastewater as described in claim 6, characterized in that, Includes the following steps: S1. Wastewater is fed into an aerated micro-electrolysis tank for aerated micro-electrolysis treatment. S2. The wastewater treated in step S1 is fed into an oxidation tank for photocatalytic oxidation treatment. S3. Input the wastewater treated in step S2 into the electrodialysis device for electrodialysis treatment; S4. The wastewater treated in step S3 is fed into the algae and bacteria biochemical tank for degradation treatment, and then discharged.

8. The method for deep treatment of high-salinity chemical wastewater as described in claim 7, characterized in that, Step S2 also includes adding an oxidant during the photocatalytic treatment process, with the amount of oxidant added being 2-4 g / L.

9. The method for deep treatment of high-salinity chemical wastewater as described in claim 7, characterized in that, In step S3, the voltage of the electrodialysis treatment is 30-40V, the current is 4-5A, and the time is 40-80min.

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