High-recycling-rate wastewater zero-discharge treatment method and high-recycling-rate wastewater zero-discharge treatment system

Abstract

The invention discloses a high-recycling-rate wastewater zero-discharge treatment method and system, and belongs to the technical field of water treatment systems. The treatment system comprises a high-density sedimentation tank, a nano microbubble-iron carbon reaction device, a UASB (Upflow Anaerobic Sludge Blanket) reactor, a sludge treatment system, a crystallization and granulation fluidized bed, a sand filtration device, an ultrafiltration device, an ultraviolet disinfection device, a nanofiltration device, a reverse osmosis device and an evaporative crystallization device, the raw water tank is sequentially connected with a high-density sedimentation tank, a nano microbubble-iron carbon reaction device, a UASB (Upflow Anaerobic Sludge Blanket) reactor, a crystallization and granulation fluidized bed, a sand filtration device, an ultrafiltration device, an ultraviolet disinfection device, a nanofiltration device, a reverse osmosis device and an evaporative crystallization device; excess sludge discharged by the UASB reactor is treated by a sludge treatment system. The iron-carbon micro-electrolysis and nano micro-bubble technology is utilized to pretreat the high-salt organic wastewater, so that long-chain and cyclic organic pollutants which are difficult to degrade are subjected to bond breaking, the biotoxicity of the wastewater is remarkably reduced, the biodegradability of the wastewater is improved, and the subsequent treatment of wastewater organic matters by a biological method is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment systems, and in particular relates to a high resource utilization rate wastewater zero-discharge treatment method and system. Background Art

[0002] High-salt organic wastewater refers to industrial wastewater with a total dissolved solid (TDS) concentration higher than 1% and a chemical oxygen demand (COD) of thousands to tens of thousands of mg / L, which has the dual pollution characteristics of high salt and complex organic matter. It mainly comes from industries such as petrochemicals, pharmaceuticals, pesticide production, food processing, and printing and dyeing production. The direct discharge of salt and organic pollutants (such as benzene series and heterocyclic compounds) in this type of wastewater will cause multiple environmental risks: salt ions break the ion balance of the water body, causing osmotic pressure imbalance and even death of aquatic organisms; difficult-to-degrade organic matter is biologically toxic and can be enriched through the food chain to threaten ecological safety. Therefore, it is necessary to use technologies such as membrane separation, advanced oxidation, and evaporation crystallization to achieve salt resource recovery and efficient degradation of organic matter.

[0003] The crystallization granulation fluidized bed uses the principle of fluidized bed to make the granular material crystallize and granulate in a fluidized state. By adding chemical agents to the water, the calcium and magnesium ions in the water react to generate corresponding crystals, which adhere to the surface of the pre-added crystal seeds, thereby reducing the hardness of the water. This technology has the advantages of high treatment efficiency, stable water output, simple operation and management, small footprint, and no wastewater discharge.

[0004] Membrane separation technology + evaporation concentration technology to recover salt is an efficient and environmentally friendly method of salt recovery. Membrane separation technology, such as nanofiltration membrane, is used to pre-treat saline wastewater. According to the membrane's selective permeability to different ions, the salt in the wastewater is separated from other impurities, so that the salt is initially concentrated. The concentrated brine after membrane separation is sent to the evaporation concentration system, and the water is evaporated by heating to further increase the concentration of the brine until it reaches saturation, thereby causing the salt to crystallize and precipitate. This combination of technologies can not only effectively recover salt resources and reduce pollution to the environment, but also reduce processing costs and achieve resource recycling.

[0005] In the process of treating high-salt organic wastewater, direct biochemical treatment is used. Physical and chemical treatment has high operating costs and is difficult to achieve the expected purification effect. Usually, a combination of technologies is used. The combined process not only overcomes the limitations of biological methods for treating difficult-to-degrade organic pollutants, but also reduces treatment costs and improves the quality of effluent.

[0006] In summary, in the existing technology, the resource treatment of high-salt organic wastewater directly adopts physical and chemical methods, which has high operating costs and poor organic effect, and is very easy to cause organic pollution in membrane treatment, making it difficult to meet the standards for water production and reuse; high-salt organic wastewater has a high organic matter content, and contains many difficult-to-degrade organic pollutants such as benzene and cyclic aromatic hydrocarbons. Direct biological treatment will have a negative impact on the growth, reproduction and metabolism of microorganisms, inhibit the activity of microorganisms, and make it difficult for them to perform normal decomposition and purification functions; salt substances in high-salt organic wastewater are directly precipitated and discharged with sludge, which is easy to cause waste of resources, increase the amount of sludge, and increase the cost of sludge disposal. Summary of the invention

[0007] The present invention aims at recycling salt resources and water resources in high-salt organic wastewater, and provides a high-resource recovery rate wastewater zero-discharge treatment method and system.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A high resource utilization rate wastewater zero discharge treatment system, the treatment system comprising a high-density sedimentation tank, a nano-micro bubble-iron-carbon reaction device, a UASB reactor, a sludge treatment system, a crystallization granulation fluidized bed, a sand filtration device, an ultrafiltration device, an ultraviolet disinfection device, a nanofiltration device, a reverse osmosis device and an evaporation crystallization device;

[0010] The sludge treatment system includes a sludge storage tank and a sludge dewatering machine;

[0011] The raw water pool is connected in sequence to a high-density sedimentation tank, a nano-micro bubble-iron-carbon reaction device, a UASB reactor, a crystallization granulation fluidized bed, a sand filtration device, an ultrafiltration device, an ultraviolet disinfection device, a nanofiltration device, a reverse osmosis device, and an evaporation crystallization device;

[0012] The residual sludge discharged from the UASB reactor flows into a sludge storage tank, which is connected to a sludge dewatering machine for sludge dewatering.

[0013] Furthermore, the sludge dewatering machine is one of a belt filter press, a plate and frame filter press, a chamber filter press, and a centrifugal sludge dewatering machine.

[0014] A method for treating high-salt organic wastewater using the above-mentioned high-resource recovery rate wastewater zero-discharge treatment system, the method comprising:

[0015] Step 1: High-salt organic wastewater enters the high-density sedimentation tank, and through flocculation and sedimentation, the suspended solids in the water are removed and the turbidity of the water is reduced. The effluent enters the nano-micro bubble-iron-carbon micro-electrolysis reaction device, and the sludge enters the sludge treatment system;

[0016] Step 2: The nano-micro bubble-iron-carbon reaction device includes a nano-micro bubble device, an iron-carbon micro-electrolysis filler and an iron-carbon micro-electrolysis reaction device; the iron-carbon micro-electrolysis reaction device is a column reactor or a tower reactor, the iron-carbon micro-electrolysis filler is fixed inside the reactor, and the aeration holes of nano-micro bubbles are arranged in the lower layer, and the water enters from the bottom and exits from the top; the effluent enters the UASB reactor; the nano-micro bubble-iron-carbon reaction device uses the redox action of the iron-carbon micro-electrolysis filler filled inside to break the bonds of long-chain and cyclic organic matter, thereby improving the biodegradability of the wastewater. At the same time, the nano-micro bubbles strengthen the redox reaction, enhance the treatment effect, and can also clean and activate the surface of the iron-carbon filler to prevent the filler surface from being blocked and passivated;

[0017] Step 3: domesticating and cultivating salt-tolerant microbial flora inside the UASB reactor, using the secondary sedimentation tank of the seaside sewage treatment plant as the inoculated sludge, controlling the salinity of the wastewater in the initial stage of cultivation, and increasing it in sequence from 0.5%, 1%, 1.5%, 2%, and 3%, and finally cultivating bacteria that can treat wastewater with a salinity of less than 3%; the hydraulic retention time of the salt-tolerant UASB reactor is 12-36h, the sludge retention time is 10-30 days, and the anaerobic environment with a dissolved oxygen content of less than 0.2mg / L is maintained; the effluent enters the crystallization granulation fluidized bed, and the sludge enters the sludge treatment system; the UASB reactor, cultivating and domesticating salt-tolerant microorganisms to form a stable microbial community in the UASB reactor, has a high removal efficiency for organic matter in high-salt organic wastewater, can convert most of the organic matter into biogas, and remove organic matter in the water;

[0018] Step 4: The sludge treatment system includes a sludge storage tank, sludge dehydration and mud cake transportation, which is used to dehydrate the generated sludge and return the filtrate after sludge dehydration to the high-density sedimentation tank to enhance the flocculation effect of the flocculant;

[0019] Step 5: Crystallization granulation fluidized bed, add appropriate seed particles and chemical agents into the device, so that the hardness ions in the water are crystallized and precipitated on the surface of the seed crystals to form larger particles, thereby achieving hardness removal, and the effluent enters the sand filter device;

[0020] Step 6: The sand filter device is a multi-media filter or a manganese sand filter, which is mainly used to remove impurities in the water, and the effluent enters the ultrafiltration device;

[0021] Step 7: The ultrafiltration device is used to further remove impurities in the water to prevent the reverse osmosis membrane from being blocked, and the effluent enters the ultraviolet disinfection device;

[0022] Step 8: In the ultraviolet sterilization device, ultraviolet lamps are used to sterilize the microorganisms that may remain in the wastewater to prevent the subsequent microbial growth in the wastewater; the effluent enters the nanofiltration device;

[0023] Step 9: Nanofiltration device intercepts divalent salt ions in the water, the produced water enters the reverse osmosis device, and the concentrated liquid enters the evaporation crystallization;

[0024] Step 10: The reverse osmosis device concentrates and reduces the wastewater, produces water for reuse, and the concentrated liquid enters evaporation and crystallization;

[0025] Step 11: Evaporation and crystallization: evaporate the concentrated liquid and recycle the impurity salt and sodium chloride.

[0026] Furthermore, in step one, the high-density sedimentation tank includes a rapid stirring zone, a flocculation zone and a sedimentation zone; the rapid stirring zone is added with a high molecular flocculant polyacrylamide, the addition amount is 3-10ppm, the hydraulic retention time of the rapid stirring zone is 1-6min, the hydraulic retention time of the flocculation zone is 5-20min, and the hydraulic retention time of the sedimentation zone is 20-60min.

[0027] Furthermore, in step 2, the nano-micro bubble device is one of a gas injection method, a pressurized dissolution method, a cyclonic liquid flow method or a micropore method.

[0028] Furthermore, in step 2, the preparation method of the iron-carbon micro-electrolysis filler is as follows: the iron powder is soaked in 10% sodium hydroxide solution for 30 minutes, then washed with deionized water until neutral, then soaked in 5% dilute hydrochloric acid for 30 minutes to activate it, remove the oxidized components on its surface, then washed with deionized water to neutralize it, and dried in a vacuum oven; the activated carbon is soaked in water, and the clean water is continuously replaced until the surface impurities are removed and the water no longer turns black, and then washed with deionized water and naturally air-dried; after the iron powder and the activated carbon are evenly mixed, the carrier, the metal catalyst powder, and the ammonium bicarbonate pore-forming agent are added in sequence, and mixed again The mixture is uniform, wherein the carrier is bentonite or attapulgite, accounting for 50wt.%-60wt.%; the metal catalyst powder accounts for 3wt.%; the ammonium bicarbonate pore-forming agent accounts for 3wt.%; the mass ratio of iron powder to activated carbon is 1:1-5:1; the mixture is placed in a granulator to form spheres of 5-20mm, the prepared spherical iron-carbon micro-electrolysis filler is placed in a vacuum drying oven at 105°C and dried for 2h, then moved into a vacuum tube furnace and sintered at a high temperature of 700-1000°C for 1-4h; the metal catalyst powder is one of manganese dioxide, copper oxide or copper powder.

[0029] Furthermore, in step five, the dosage of the seed particles is 0.5-10 g / L, and the seed particles are calcium carbonate seeds, calcium sulfate seeds or garnet seeds with a particle size of 0.05-0.5 mm; the chemical agents are sodium hydroxide and sodium carbonate, the dosage is 10-200 mg / L, and the reaction time is 10-30 min.

[0030] Furthermore, in step six, the multi-media filter uses quartz sand and anthracite as filter media, and the volume ratio of quartz sand to anthracite is between 1:1 and 1:2. If the iron ion content in the water exceeds the standard, a manganese sand filter is selected. There are two conditions for judging whether the iron ion exceeds the standard: 1. The iron ion content is greater than 0.3 mg / L; 2. The wastewater appears yellow or brown. Using a manganese sand filter can reduce the iron ions in the wastewater.

[0031] Furthermore, in step seven, the ultrafiltration device is a column ultrafiltration or an immersion ultrafiltration; in step eight, the ultraviolet sterilization is a low-pressure mercury lamp or a medium-pressure mercury lamp; in step nine, the nanofiltration device is a hollow fiber nanofiltration membrane, a tubular nanofiltration membrane or a roll nanofiltration membrane; in step ten, the reverse osmosis device is a two-stage reverse osmosis, the reverse osmosis recovery rate is between 70% and 90%, and the produced water is reused after the two-stage reverse osmosis.

[0032] Furthermore, in step eleven, mechanical vapor recompression evaporation (MVR evaporation) is used for evaporation and crystallization, and the impurities in the nanofiltration membrane concentrate are evaporated and crystallized for use in industrial production or building materials; the sodium chloride in the evaporated and crystallized reverse osmosis membrane concentrate can be used as a snow melting agent, etc.

[0033] The beneficial effects of the present invention compared to the prior art are:

[0034] 1. Use iron-carbon micro-electrolysis + nano-microbubble technology to pre-treat high-salt organic wastewater, break the bonds of long-chain and cyclic organic pollutants that are difficult to degrade, such as benzene and cyclic aromatic hydrocarbons, significantly reduce the biological toxicity of the wastewater, improve the biodegradability of the wastewater, and facilitate the subsequent biological treatment of organic matter in the wastewater;

[0035] 2. Using UASB reactor to cultivate salt-tolerant microorganisms, which can adapt to wastewater in high-salt environment, and then treat high-salt organic wastewater. Compared with high-order oxidation technology or other technologies to treat organic matter, biological treatment of organic matter greatly reduces the operating cost;

[0036] 3. The crystallization granulation fluidized bed removes the hardness in the wastewater and prevents subsequent reverse osmosis membrane scaling;

[0037] 4. Use nanofiltration membrane + reverse osmosis membrane + evaporation crystallization technology to realize resource recovery of wastewater salts (miscellaneous salts and sodium chloride);

[0038] 5. Use reverse osmosis membrane technology + ultraviolet sterilization to achieve wastewater reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a process flow chart of the present invention.

[0040] Figure 2 Flow chart for the preparation of iron-carbon micro-electrolysis filler. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0042] Embodiment 1:

[0043] A high resource utilization rate wastewater zero discharge treatment system, the treatment system comprising a high-density sedimentation tank, a nano-micro bubble-iron-carbon reaction device, a UASB reactor, a sludge treatment system, a crystallization granulation fluidized bed, a sand filtration device, an ultrafiltration device, an ultraviolet disinfection device, a nanofiltration device, a reverse osmosis device and an evaporation crystallization device;

[0044] The sludge treatment system includes a sludge storage tank and a plate and frame filter press;

[0045] The raw water pool is connected in sequence to a high-density sedimentation tank, a nano-micro bubble-iron-carbon reaction device, a UASB reactor, a crystallization granulation fluidized bed, a sand filtration device, an ultrafiltration device, an ultraviolet disinfection device, a nanofiltration device, a reverse osmosis device, and an evaporation crystallization device;

[0046] The residual sludge discharged from the UASB reactor flows into a sludge storage tank, which is connected to a sludge dewatering machine for sludge dewatering.

[0047] Embodiment 2:

[0048] A method for treating high-salt organic wastewater using the high resource utilization rate wastewater zero discharge treatment system of Example 1, the method comprising:

[0049] Step 1: High-salt organic wastewater enters a high-density sedimentation tank, and through flocculation and sedimentation, the suspended solids in the water are removed, the turbidity of the water is reduced, the effluent enters a nano-micro bubble-iron-carbon micro-electrolysis reaction device, and the sludge enters a sludge treatment system; the high-density sedimentation tank includes a rapid stirring zone, a flocculation zone and a sedimentation zone; the rapid stirring zone is added with a high molecular flocculant polyacrylamide, the addition amount is 7-8ppm, the hydraulic retention time of the rapid stirring zone is 4-6min, the hydraulic retention time of the flocculation zone is 12min, and the hydraulic retention time of the sedimentation zone is 30-40min;

[0050] Step 2: The nano-micro bubble-iron-carbon reaction device includes a nano-micro bubble device, an iron-carbon micro-electrolysis filler and an iron-carbon micro-electrolysis reaction device; the iron-carbon micro-electrolysis reaction device is a column reactor or a tower reactor, the iron-carbon micro-electrolysis filler is fixed inside the reactor, and the aeration holes of nano-micro bubbles are arranged in the lower layer, and the water enters from the bottom and exits from the top; the effluent enters the UASB reactor; the nano-micro bubble-iron-carbon reaction device uses the redox action of the iron-carbon micro-electrolysis filler filled inside to break the bonds of long-chain and cyclic organic matter, thereby improving the biodegradability of the wastewater. At the same time, the nano-micro bubbles strengthen the redox reaction, enhance the treatment effect, and can also clean and activate the surface of the iron-carbon filler to prevent the filler surface from being blocked and passivated;

[0051] The preparation method of the iron-carbon micro-electrolysis filler is as follows: the iron powder is soaked in 10% sodium hydroxide solution for 30 minutes, then washed with deionized water until neutral, then soaked in 5% dilute hydrochloric acid for 30 minutes to activate it, remove the oxidized components on the surface, then washed with deionized water to neutralize it, and dried in a vacuum oven; the activated carbon is soaked in clean water, and the clean water is continuously changed until the surface impurities are removed and the water no longer turns black, then washed with deionized water and naturally air-dried; after the iron powder and the activated carbon are evenly mixed, the carrier, the metal catalyst powder, and the carbon are added in sequence. ammonium bicarbonate pore-forming agent, and mixed evenly again. In the mixture, the carrier is bentonite or attapulgite, accounting for 55wt.%; the metal catalyst powder accounts for 3wt.%; the ammonium bicarbonate pore-forming agent accounts for 3wt.%; the mass ratio of iron powder to activated carbon is 3:1; the mixture is put into a granulator to make 12mm spheres, and the prepared spherical iron-carbon micro-electrolysis filler is placed in a vacuum drying oven at 105°C for 2h and then moved into a vacuum tube furnace and sintered at a high temperature of 800°C for 2h; the metal catalyst powder is manganese dioxide;

[0052] Step 3: domesticating and cultivating salt-tolerant microbial flora inside the UASB reactor, using the secondary sedimentation tank of the seaside sewage treatment plant as the inoculated sludge, controlling the salinity of the wastewater in the initial stage of cultivation, and increasing it in sequence from 0.5%, 1%, 1.5%, 2%, and 3%, and finally cultivating bacteria that can treat wastewater with a salinity of less than 3%; the hydraulic retention time of the salt-tolerant UASB reactor is 12-36h, the sludge retention time is 10-30 days, and the anaerobic environment with a dissolved oxygen content of less than 0.2mg / L is maintained; the effluent enters the crystallization granulation fluidized bed, and the sludge enters the sludge treatment system; the UASB reactor, cultivating and domesticating salt-tolerant microorganisms to form a stable microbial community in the UASB reactor, has a high removal efficiency for organic matter in high-salt organic wastewater, can convert most of the organic matter into biogas, and remove organic matter in the water;

[0053] Step 4: The sludge treatment system includes a sludge storage tank, sludge dehydration and mud cake transportation, which is used to dehydrate the generated sludge and return the filtrate after sludge dehydration to the high-density sedimentation tank to enhance the flocculation effect of the flocculant;

[0054] Step 5: Add appropriate seed particles and chemicals to the crystal granulation fluidized bed to make the hardness ions in the water crystallize and precipitate on the surface of the seed particles to form larger particles, thereby removing the hardness, and the effluent enters the sand filter device; the amount of the seed particles added is 6g / L, and the seed particles are calcium carbonate seeds with a particle size of 0.3mm; the chemical agent is sodium hydroxide, the amount added is 50-60mg / L, and the reaction time is 20min.

[0055] Step 6: The sand filter device is a multi-media filter or a manganese sand filter, which is mainly used to remove impurities in the water, and the effluent enters the ultrafiltration device; the multi-media filter uses quartz sand and anthracite as filter media, and the volume ratio of quartz sand to anthracite is between 1:1 and 1:2. If the iron ion content in the water exceeds the standard, a manganese sand filter is selected. There are two conditions for judging whether the iron ion exceeds the standard: 1. The iron ion content is greater than 0.3 mg / L; 2. The wastewater appears yellow or brown. Using a manganese sand filter can reduce the iron ions in the wastewater.

[0056] Step 7: The ultrafiltration device is used to further remove impurities in the water to prevent the reverse osmosis membrane from being blocked, and the effluent enters the ultraviolet sterilization device; the ultrafiltration device is a column ultrafiltration device;

[0057] Step 8: In the ultraviolet sterilization device, ultraviolet lamps are used to sterilize the microorganisms that may remain in the wastewater to prevent the subsequent microbial growth in the wastewater; the effluent enters the nanofiltration device; the ultraviolet sterilization is a low-pressure mercury lamp;

[0058] Step nine: a nanofiltration device is used to intercept divalent salt ions in the water, and the produced water enters the reverse osmosis device, and the concentrated liquid enters the evaporation crystallization; the nanofiltration device is a hollow fiber nanofiltration membrane;

[0059] Step 10: The reverse osmosis device concentrates and reduces the wastewater, produces water for reuse, and the concentrated liquid enters evaporation and crystallization; the reverse osmosis device is a two-stage reverse osmosis, and the reverse osmosis recovery rate is between 85% and 90%. The produced water is reused after the two-stage reverse osmosis.

[0060] Step 11: Evaporation and crystallization: The concentrated liquid is evaporated and treated, and the impurity salt and sodium chloride are utilized as resources. In step 11, the evaporation and crystallization adopts mechanical vapor recompression evaporation (MVR evaporation), and the impurity salt of the nanofiltration membrane concentrated liquid is evaporated and crystallized for industrial production or building materials; the sodium chloride of the reverse osmosis membrane concentrated liquid can be used as a snow melting agent, etc.

[0061] The method of Example 2 was used to treat a certain chemical wastewater. The water quality information of the chemical wastewater is shown in the following table. The treated water volume is 780 d / t. The treatment results are shown in the following table.

[0062]

Claims

1. A high resource utilization rate wastewater zero discharge treatment system, characterized by: The treatment system comprises a high-density sedimentation tank, a nano-micro bubble-iron-carbon reaction device, a UASB reactor, a sludge treatment system, a crystallization granulation fluidized bed, a sand filtration device, an ultrafiltration device, an ultraviolet disinfection device, a nanofiltration device, a reverse osmosis device and an evaporation crystallization device; The sludge treatment system includes a sludge storage tank and a sludge dewatering machine; The raw water pool is connected in sequence to a high-density sedimentation tank, a nano-micro bubble-iron-carbon reaction device, a UASB reactor, a crystallization granulation fluidized bed, a sand filtration device, an ultrafiltration device, an ultraviolet disinfection device, a nanofiltration device, a reverse osmosis device, and an evaporation crystallization device; The residual sludge discharged from the UASB reactor flows into a sludge storage tank, which is connected to a sludge dewatering machine for sludge dewatering.

2. A high resource utilization rate wastewater zero discharge treatment system according to claim 1, characterized in that: The sludge dewatering machine is one of a belt filter press, a plate and frame filter press, a chamber filter press, and a centrifugal sludge dewatering machine.

3. A method for treating high-salt organic wastewater using the high-resource utilization rate wastewater zero-discharge treatment system according to claim 1 or 2, characterized in that: The method is: Step 1: High-salt organic wastewater enters the high-density sedimentation tank, and through flocculation and sedimentation, the suspended matter in the water is removed and the turbidity of the water is reduced. The effluent enters the nano-micro bubble-iron-carbon reaction device, and the sludge enters the sludge treatment system; Step 2: The nano-micro bubble-iron-carbon reaction device includes a nano-micro bubble device, an iron-carbon micro-electrolysis filler and an iron-carbon micro-electrolysis reaction device; the iron-carbon micro-electrolysis reaction device is a column reactor or a tower reactor, the iron-carbon micro-electrolysis filler is fixed inside the reactor, and aeration holes of nano-micro bubbles are arranged in the lower layer, and water enters from the bottom and exits from the top; the effluent enters the UASB reactor; Step 3: domesticating and cultivating salt-tolerant microbial flora inside the UASB reactor, using the secondary sedimentation tank of the seaside sewage treatment plant as inoculated sludge, controlling the salinity of the wastewater in the initial stage of cultivation, and increasing it from 0.5%, 1%, 1.5%, 2%, and 3% in sequence, and finally cultivating bacteria that can treat wastewater with a salinity of less than 3%; the hydraulic retention time of the salt-tolerant UASB reactor is 12-36h, the sludge retention time is 10-30 days, and the anaerobic environment with dissolved oxygen below 0.2mg / L is maintained; the effluent enters the crystallization granulation fluidized bed, and the sludge enters the sludge treatment system; Step 4: The sludge treatment system includes a sludge storage tank, sludge dehydration and mud cake transportation, which is used to dehydrate the generated sludge and return the filtrate after sludge dehydration to the high-density sedimentation tank to enhance the flocculation effect of the flocculant; Step 5: Crystallization granulation fluidized bed, add appropriate seed particles and chemical agents into the device, so that the hardness ions in the water are crystallized and precipitated on the surface of the seed crystals to form larger particles, thereby achieving hardness removal, and the effluent enters the sand filter device; Step 6: The sand filter device is a multi-media filter or a manganese sand filter, and the effluent enters the ultrafiltration device; Step 7: The ultrafiltration device is used to further remove impurities in the water to prevent the reverse osmosis membrane from being blocked, and the effluent enters the ultraviolet disinfection device; Step 8: In the ultraviolet sterilization device, ultraviolet lamps are used to sterilize the microorganisms that may remain in the wastewater to prevent the subsequent microbial growth in the wastewater; the effluent enters the nanofiltration device; Step 9: Nanofiltration device intercepts divalent salt ions in the water, the produced water enters the reverse osmosis device, and the concentrated liquid enters the evaporation crystallization; Step 10: The reverse osmosis device concentrates and reduces the wastewater, produces water for reuse, and the concentrated liquid enters evaporation and crystallization; Step 11: Evaporation and crystallization: evaporate the concentrated liquid and recycle the impurity salt and sodium chloride.

4. A high resource utilization rate wastewater zero discharge treatment method according to claim 3, characterized in that: In step one, the high-density sedimentation tank includes a rapid stirring zone, a flocculation zone and a sedimentation zone; the rapid stirring zone is added with a high molecular flocculant polyacrylamide, the addition amount is 3-10ppm, the hydraulic retention time of the rapid stirring zone is 1-6min, the hydraulic retention time of the flocculation zone is 5-20min, and the hydraulic retention time of the sedimentation zone is 20-60min.

5. A high resource utilization rate wastewater zero discharge treatment method according to claim 3, characterized in that: In step 2, the nano-micro bubble device is one of gas injection method, pressure dissolution method, cyclonic liquid flow method or micropore method.

6. A high resource utilization rate wastewater zero discharge treatment method according to claim 3 or 5, characterized in that: In step 2, the preparation method of the iron-carbon micro-electrolysis filler is as follows: the iron powder is soaked in 10% sodium hydroxide solution for 30 minutes, then washed with deionized water until neutral, then soaked in 5% dilute hydrochloric acid for 30 minutes to activate it, remove the oxidized components on the surface, then washed with deionized water to neutralize it, and dried in a vacuum oven; the activated carbon is soaked in clean water, and the clean water is continuously changed until the surface impurities are removed and the water no longer turns black, then washed with deionized water and naturally air-dried; after the iron powder and activated carbon are evenly mixed, the carrier, metal catalyst powder, and ammonium bicarbonate pore-forming agent are added in sequence, and mixed evenly again In the mixture, the carrier is bentonite or attapulgite, accounting for 50wt.%-60wt.%; the metal catalyst powder accounts for 3wt.%; the ammonium bicarbonate pore-forming agent accounts for 3wt.%; the mass ratio of iron powder to activated carbon is 1:1-5:1; the mixture is placed in a granulator to form spheres of 5-20mm, the prepared spherical iron-carbon micro-electrolysis filler is placed in a vacuum drying oven at 105°C and dried for 2h, then moved into a vacuum tube furnace and sintered at a high temperature of 700-1000°C for 1-4h; the metal catalyst powder is one of manganese dioxide, copper oxide or copper powder.

7. A high resource utilization rate wastewater zero discharge treatment method according to claim 3, characterized in that: In step five, the dosage of the seed particles is 0.5-10 g / L, and the seed particles are calcium carbonate seeds, calcium sulfate seeds or garnet seeds with a particle size of 0.05-0.5 mm; the chemical agents are sodium hydroxide and sodium carbonate, the dosage is 10-200 mg / L, and the reaction time is 10-30 min.

8. A high resource utilization rate wastewater zero discharge treatment method according to claim 3, characterized in that: In step six, the multi-media filter uses quartz sand and anthracite as filter media, and the volume ratio of quartz sand to anthracite is between 1:1 and 1:2; if the iron ion content in the water exceeds the standard, a manganese sand filter is selected.

9. A high resource utilization rate wastewater zero discharge treatment method according to claim 3, characterized in that: In step seven, the ultrafiltration device is a column ultrafiltration or an immersion ultrafiltration; in step eight, the ultraviolet sterilization is a low-pressure mercury lamp or a medium-pressure mercury lamp; in step nine, the nanofiltration device is a hollow fiber nanofiltration membrane, a tubular nanofiltration membrane or a roll nanofiltration membrane; in step ten, the reverse osmosis device is a two-stage reverse osmosis, the reverse osmosis recovery rate is between 70% and 90%, and the produced water is reused after the two-stage reverse osmosis.

10. A high resource utilization rate wastewater zero discharge treatment method according to claim 3, characterized in that: In step eleven, the evaporative crystallization adopts mechanical steam recompression evaporation.

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