Reverse osmosis concentrated water cleaning treatment system and treatment method thereof

Abstract

The invention provides a reverse osmosis concentrated water cleaning treatment system and a treatment method thereof, and relates to the technical field of water treatment. The system comprises a descaling, turbidity-removing and organic matter-removing integrated fluidized bed subsystem, an electrodialysis subsystem and a secondary reverse osmosis subsystem which are arranged in sequence, the descaling, turbidity-removing and organic matter-removing integrated fluidized bed subsystem comprises a crystallization and granulation fluidized bed reactor, a seed crystal feeding unit, an alkali liquor feeding unit, a medicament feeding unit, a particle discharge unit, a sludge discharge unit, a concentrated water injection unit and a water outlet unit, and a solid-liquid separator is integrally arranged at the top of the crystallization and granulation fluidized bed reactor. The system disclosed by the invention can realize multiple effects of descaling, turbidity removal and organic matter removal, and has the characteristics of small occupied area, cyclic utilization of chemicals, more recovered products, high organic matter removal rate, cleanness and high efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a reverse osmosis concentrated water cleaning treatment system and a treatment method thereof. Background Art

[0002] Industrial production will generate a large amount of wastewater, and increasing the reuse rate of wastewater is a requirement for sustainable development. "Primary treatment + secondary treatment + deep treatment + reverse osmosis treatment" and then reuse is the wastewater treatment process adopted by most companies. Reverse osmosis treatment produces a large amount of concentrated water, which accounts for about 15-30% of the treated water. Reverse osmosis concentrated water has the characteristics of high hardness, high salt content, and high organic matter content. It is often treated by evaporation and crystallization, and the treatment cost is relatively high. Some companies use reverse osmosis concentrated water in a quality-oriented manner. For example, reverse osmosis concentrated water is used for blast furnace slag flushing in the steel industry, but the amount is limited. Therefore, in production practice, the reuse rate of industrial wastewater is often reduced due to the high cost of reverse osmosis concentrated water treatment, and reverse osmosis concentrated water cleaning treatment technology is urgently needed.

[0003] Many domestic researchers treat reverse osmosis brine by electrochemical oxidation, Fenton oxidation, ozone catalytic oxidation, UV / O3 coupled oxidation treatment, activated carbon adsorption, etc. The main purpose is to remove organic matter in the water, without involving desalination, descaling and other issues. In the paper "Application of Reverse Osmosis in Steel Wastewater Treatment" (Metallurgical Power, 2023, (3)), reverse osmosis technology is used to perform secondary desalination on brine to achieve brine reduction. This technology has problems such as high secondary reverse osmosis pressure, high energy consumption, easy scaling of membrane components, and incomplete treatment of brine. In the paper "Design and Application of Crystallization Granulation Fluidized Bed Technology in Brine Softening and Hardness Removal" (Guangdong Chemical Industry, 2023, 50 (2)), crystallization granulation fluidized bed technology is used to perform chemical hardness removal pretreatment on reverse osmosis brine, without involving turbidity removal and further treatment issues.

[0004] In the invention patent "A method and system for resource-based treatment of reverse osmosis concentrated brine by bipolar membrane electrodialysis" (application number 202310374819.3), calcium and magnesium precipitants are added to the reverse osmosis concentrated brine to remove hardness and then filtered, then organic matter is removed by electro-Fenton oxidation, and then filtered a second time, and then treated by a bipolar membrane electrodialysis device. This technology uses precipitation to remove scale, which occupies a large area; multiple filtrations require a lot of equipment; electro-Fenton oxidation removes organic matter, which is expensive.

[0005] In the invention patent "A zero-discharge treatment method for reverse osmosis concentrated water" (application number 201611061964.2), the method is to treat the pre-treated reverse osmosis concentrated brine with nanofiltration to obtain SO4-rich 2 -Mg 2+ After the nanofiltration concentrate is concentrated, it can be mixed with the permeate to precipitate and remove CaSO4, and then further separated by crystallization technology;+ , Cl - 、NO3 - , K + , Ca 2+ The nanofiltration permeate is concentrated to near saturation by medium-pressure reverse osmosis, multi-effect evaporation, multi-effect membrane distillation and other processes to recover fresh water resources. Although this method recovers fresh water and solid salts and eliminates the pollution of reverse osmosis concentrated water, the evaporation and crystallization process is expensive, the solid salts produced are difficult to separate, and the process will also cause secondary pollution.

[0006] In the invention patent "A method and system for resource utilization of industrial concentrated brine" (application number 201810876087.7), after industrial concentrated brine is mixed with alkali solution, the microfiltration system removes the precipitate, and then the nanofiltration system obtains solution a mainly containing monovalent salts and solution b mainly containing divalent salts. Solution a is concentrated by the reverse osmosis system and evaporated and crystallized to obtain industrial sodium chloride products. Solution b is further removed by resin exchange and then electrolyzed to obtain alkali solution and sulfuric acid solution. Although the invention can reduce the system's dosing cost by recycling the alkali solution after electrolysis, it uses high-energy evaporation and crystallization technology.

[0007] Therefore, although there are many studies on the treatment of reverse osmosis concentrate, the following problems still exist: ① There are many studies on the removal of single pollution factors, such as organic matter, hardness, and salt, and there is still a lack of clean and efficient overall treatment technology; ② Although there are individual technologies involving overall treatment, the process is relatively complicated, the process is long, there are many equipments, the land area is large, and the actual promotion value is low; ③ The overall treatment technology still lacks acid and alkali recovery and recycling technology, and has not solved the problems of high energy consumption, high cost, and low resource recovery rate faced by reverse osmosis concentrate treatment. Summary of the invention

[0008] The purpose of the present invention is to provide a reverse osmosis concentrated water cleaning treatment system and a treatment method thereof, so as to solve the problems faced by the current reverse osmosis concentrated water treatment technology, such as long treatment process, multiple equipment, large floor space, low recovery rate of useful components, large consumption of chemicals, and high energy consumption.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] On the one hand, the present invention provides a reverse osmosis concentrated water cleaning treatment system, including a fluidized bed subsystem for descaling, turbidity removal and organic matter removal, an electrodialysis subsystem and a secondary reverse osmosis subsystem arranged in sequence;

[0011] The scale, turbidity and organic matter removal integrated fluidized bed subsystem comprises a crystallization granulation fluidized bed reactor, a crystal seed delivery unit, an alkali solution delivery unit, a reagent delivery unit, a particle discharge unit, a sludge discharge unit, a concentrated water injection unit and a water outlet unit. A solid-liquid separator is integrated on the top of the crystallization granulation fluidized bed reactor. The crystal seed delivery unit, the alkali solution delivery unit, the particle discharge unit and the concentrated water injection unit are all connected to the crystallization granulation fluidized bed reactor. The reagent delivery unit, the sludge discharge unit and the water outlet unit are all connected to the solid-liquid separator. The water outlet unit is also connected to the acid delivery unit.

[0012] The crystallization granulation fluidized bed reactor comprises a variable diameter cylinder, in which the alkali solution and the concentrated water are mixed and crystallized by convection effect;

[0013] The electrodialysis subsystem includes a bipolar membrane electrodialysis device, and the secondary reverse osmosis subsystem includes a secondary reverse osmosis device. The bipolar membrane electrodialysis device is respectively connected to the water outlet unit, the alkali solution addition unit, the acid solution addition unit, and the secondary reverse osmosis device.

[0014] Furthermore, the reducer cylinder as a whole is a Venturi tube structure, the top of the reducer cylinder is closed, and a plurality of water outlet holes are provided on its upper side wall, the solid-liquid separator includes an annular mud discharge cylinder arranged on the outer side of the upper part of the reducer cylinder, the bottom cross-section of the mud discharge cylinder is "V"-shaped, a partition is arranged in the mud discharge cylinder, the partition divides the upper part of the inner cavity of the mud discharge cylinder into a liquid inlet chamber and a liquid outlet chamber, a plurality of pipeline mixers in a circular array are arranged on the upper part of the liquid inlet chamber, a plurality of inclined plates are equidistantly arranged on the upper part of the liquid outlet chamber, a vortex guide pipe is arranged on the upper part of the mixing tube body of the pipeline mixer, and a spiral sheet is arranged on the lower part, the vortex guide pipe is connected to the water outlet hole on the reducer cylinder through a connecting pipe, the connecting pipe is arranged obliquely, and the connecting pipe is tangentially connected to the water outlet hole and the vortex guide pipe.

[0015] Preferably, a guide plate is further provided in the mud discharge tube, and the guide plate is located below the pipeline mixer.

[0016] Furthermore, the seed delivery unit includes a seed mixing bucket, a seed delivery bucket is arranged above the seed mixing bucket, a water inlet pump is arranged on the water inlet pipe of the seed mixing bucket, the seed delivery bucket is connected to the lower part of the variable diameter cylinder through a seed delivery pipe, and a seed delivery pump is arranged on the seed delivery pipe.

[0017] Furthermore, the drug dosing unit includes a dosing tank and a drug dosing pipe. The drug dosing pipe includes a main pipe and several branch pipes connected to the main pipe. The dosing tank is connected to the main pipe. A dosing pump and a drug dosing control valve are arranged on the main pipe. The outlet end of the branch pipe extends into the upper inner part of the mixing tube body of the corresponding pipeline mixer.

[0018] Furthermore, the sludge discharge unit comprises a sludge discharge pipe, the sludge discharge pipe is connected to the bottom of the sludge discharge barrel, a sludge pump is arranged on the sludge discharge pipe, and a sludge collection tank is arranged below the outlet of the sludge discharge pipe.

[0019] Furthermore, the particle discharge unit comprises a particle discharge pipe, which is connected to the lower part of the variable diameter cylinder, a particle discharge valve is arranged on the particle discharge pipe, and a particle collection bucket is arranged below the outlet of the particle discharge pipe.

[0020] Furthermore, the concentrated water injection unit includes a concentrated water injection pipe, on which a pressure gauge and a concentrated water pump are arranged, and the outlet of the concentrated water injection pipe is connected to a concentrated water distribution plate, which is located in the lower inner part of the variable diameter cylinder, and adopts a concave structure plate body, and a number of water distribution caps are evenly arranged on the concentrated water distribution plate.

[0021] Furthermore, the alkali solution dosing unit includes an alkali storage tank and an alkali solution distribution plate. The alkali storage tank is connected to the alkali solution distribution plate through an alkali solution dosing pipe. An alkali solution pump and an alkali solution dosing control valve are arranged on the alkali solution dosing pipe. The alkali solution distribution plate is located directly above the concentrated water distribution plate and is arranged opposite to the concentrated water distribution plate. The alkali solution distribution plate adopts a concave structure plate body. A number of alkali solution nozzles are evenly arranged on the alkali solution distribution plate. The liquid inlet of the alkali storage tank is connected to the bipolar membrane electrodialysis device.

[0022] Furthermore, the water outlet unit includes a water outlet trough and a water outlet pipe. The annular water outlet trough is arranged at the upper end of the outer wall of the mud discharge tube. The water outlet trough is connected to the bipolar membrane electrodialysis device through the water outlet pipe. The water outlet pipe is provided with a real-time online pH detector and an online turbidity detector; the acid liquid dosing unit includes an acid storage tank, the acid storage tank is connected to the water outlet pipe through an acid liquid dosing pipe, an acid liquid pump is provided on the acid liquid dosing pipe, and the liquid inlet of the acid storage tank is connected to the bipolar membrane electrodialysis device.

[0023] Furthermore, the bipolar membrane electrodialysis device adopts TWED-32-62S type, the cation membrane adopts TWDDC2 type, the anion membrane adopts TWDDA35 type, the bipolar membrane adopts TWEDBM type, and the membrane logarithm is 60.

[0024] Furthermore, the secondary reverse osmosis device adopts LCLEPRO-4040 model membrane elements.

[0025] On the other hand, the present invention provides a method for cleaning and treating concentrated water from a reverse osmosis, which is treated by the above-mentioned system for cleaning and treating concentrated water from a reverse osmosis, and specifically comprises:

[0026] (1) The reverse osmosis concentrated water is fed into a crystallization granulation fluidized bed reactor through a concentrated water injection unit, and then the alkali solution, fine crystal seeds, and reagents are respectively fed through an alkali solution feeding unit, a seed feeding unit, and a reagent feeding unit. During the operation of the crystallization granulation fluidized bed reactor, the coarse crystal seed particles rich in calcium carbonate and the concentrated sludge rich in magnesium hydroxide are respectively recovered through a particle discharge unit and a sludge discharge unit. The coarse crystal seed particles rich in calcium carbonate are sent to a wastewater desulfurization system for wastewater desulfurization, and the concentrated sludge rich in magnesium hydroxide is sent to a reprocessing link as an industrial raw material;

[0027] (2) The concentrated water treated by the integrated fluidized bed subsystem for descaling, turbidity removal and organic matter removal is sent to the electrodialysis subsystem through the water outlet unit for desalination and recovery of alkali and acid. The alkali and acid are sent to the alkali storage tank and acid storage tank respectively;

[0028] (3) The effluent from the electrodialysis subsystem is sent to the secondary reverse osmosis subsystem for treatment. The secondary reverse osmosis clean water is reused, and the secondary reverse osmosis concentrated water enters the water inlet of the enterprise's wastewater treatment system, or is directly used according to quality.

[0029] Furthermore, the fine-grained seed crystals are at least one of garnet, quartz, and calcium carbonate particles with a particle size of 60 to 800 meshes.

[0030] Preferably, the fine-grained seed crystals are garnet particles with a particle size of 60 to 100 meshes.

[0031] Furthermore, the alkali solution added to the crystallization granulation fluidized bed reactor is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, calcium hydroxide, and calcium bicarbonate, and the amount used is such that the pH value in the crystallization granulation fluidized bed reactor is between 9.5 and 11.0.

[0032] Preferably, the alkali solution added to the crystallization granulation fluidized bed reactor is at least one of sodium hydroxide and sodium carbonate, and the amount used is such that the pH value in the crystallization granulation fluidized bed reactor is between 10.0 and 11.0.

[0033] Furthermore, the reagent includes flocculant and powdered activated carbon. The flocculant is at least one of polyaluminum chloride and hydrolyzed polyacrylamide. The amount of polyaluminum chloride is 100-500 mg / L, and the amount of hydrolyzed polyacrylamide is 0-5 mg / L. The amount of flocculant is automatically adjusted according to the online detection result of effluent turbidity by an online turbidity detector. The amount of powdered activated carbon is 0-500 mg / L, so that the effluent CODCr value is less than 100 mg / L. The amount of powdered activated carbon is adjusted according to the concentration of organic matter in the effluent of the crystallization granulation fluidized bed reactor.

[0034] Furthermore, according to the online detection result of the water inlet pressure gauge, the removal time of the coarse seed particles is determined. The coarse seed particles are particles with a particle size of 2 to 3 mm and a calcium carbonate content higher than 95%.

[0035] Furthermore, the concentrated sludge collected in the sludge collection tank has a moisture content of 82-87% and a magnesium hydroxide content higher than 80%.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. In the present invention, coarse seed particles rich in calcium carbonate and concentrated sludge rich in magnesium hydroxide are recovered through a crystallization granulation fluidized bed reactor and a solid-liquid separator, and are used as a desulfurizer and industrial raw material for a desulfurization system for comprehensive utilization; an electrodialysis subsystem is used to desalinate and recover alkali solution and acid solution, which are used for fluidized bed descaling and effluent neutralization, respectively; the effluent of the electrodialysis subsystem is treated by a secondary reverse osmosis subsystem to recover clean water, and the concentrated water is used separately or returned to the enterprise wastewater treatment system; the clean and efficient characteristics of the system are fully reflected.

[0038] 2. The variable diameter cylinder of the crystallization granulation fluidized bed reactor of the present invention is designed with reaction areas of different diameters so that different areas in the fluidized bed have different rising flow rates, so that coarse seed particles rich in calcium carbonate of different particle sizes are suspended in different areas, and the newly formed calcium carbonate adsorbs organic matter, thereby achieving multiple effects of descaling, deturbidity and removal of organic matter.

[0039] 3. In the present invention, the alkali solution distribution plate and the concentrate water distribution plate form focused convection. The strong convection effect makes the concentrate water and the alkali solution highly mixed in the focal area between the alkali solution distribution plate and the concentrate water distribution plate, increasing the collision frequency and contact area between the fluids, thereby improving the reaction efficiency and mass transfer effect between the two, helping to promote the crystallization process in the local area, accelerating the precipitation of impurities in the concentrate water and the formation of particles, and further improving the concentrate water treatment efficiency.

[0040] 4. The present invention only uses three sets of equipment, namely, a fluidized bed subsystem for removing scale, turbidity and organic matter, an electrodialysis subsystem and a two-stage reverse osmosis subsystem, to treat reverse osmosis concentrated water. The equipment is small, easy to control automatically, and the floor space is reduced. The acid and alkali cycle is recycled and the reagent cost is low. The final concentrated water volume is low and the pollutant concentration is low, which is convenient for separate utilization or returned to the wastewater treatment system without significantly affecting the entire wastewater treatment. The entire process has the advantages of cleanliness and energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of a reverse osmosis concentrated water cleaning treatment system in the present invention;

[0042] Figure 2 for Figure 1 A three-dimensional diagram of the connection relationship between the middle reducer cylinder and the pipeline mixer;

[0043] Figure 3 for Figure 2 The main cross-sectional view of the connection relationship between the middle reducer cylinder and the pipeline mixer;

[0044] Figure 4 for Figure 1 Bottom view of the middle alkali solution distribution plate;

[0045] Figure 5 for Figure 1A three-dimensional diagram of a medium-concentrate water distribution plate;

[0046] Figure 6 A process flow chart of a reverse osmosis concentrated water cleaning treatment method in the present invention;

[0047] Figure 7 This is an apparent diagram of the coarse seed particles rich in calcium carbonate recovered in Example 3 of the present invention;

[0048] Figure 8 This is a color comparison diagram of water samples before and after reverse osmosis concentrated water treatment in Example 3 of the present invention;

[0049] Figure numerals: 11-water inlet pump, 12-seed delivery bucket, 13-seed mixing bucket, 14-seed dosing pump, 15-seed dosing pipe, 21-alkali storage tank, 22-alkali solution pump, 23-alkali solution dosing control valve, 24-alkali solution dosing pipe, 25-alkali solution distribution plate, 2501-alkali solution nozzle, 31-dosing tank, 32-dosing pump, 33-drug dosing control valve, 34-drug dosing pipe, 41-mud discharge cylinder, 42-partition, 43-pipeline mixer, 4301-mixing tube body, 4302-swirl Guide pipe, 4303-spiral blade, 44-inclined plate, 45-drain pipe, 46-guide plate, 47-sludge pump, 48-sludge collection tank, 51-particle discharge valve, 52-particle collection bucket, 61-reducing cylinder, 62-concentrate pump, 63-pressure gauge, 64-concentrate distribution plate, 6401-water distribution cap, 65-water outlet trough, 66-pH real-time online detector, 67-online turbidity detector, 68-acid storage tank, 69-acid pump, 71-bipolar membrane electrodialysis device, 81-secondary reverse osmosis device. DETAILED DESCRIPTION

[0050] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments.

[0051] Example 1

[0052] Please refer to the attached Figure 1-5As shown, a reverse osmosis concentrated water cleaning treatment system provided in this embodiment includes an integrated fluidized bed subsystem for descaling, turbidity removal and organic matter removal, an electrodialysis subsystem and a secondary reverse osmosis subsystem which are arranged in sequence; the integrated fluidized bed subsystem for descaling, turbidity removal and organic matter removal includes a crystallization granulation fluidized bed reactor, a seed delivery unit, an alkali solution delivery unit, a chemical delivery unit, a particle discharge unit, a sludge discharge unit, a concentrated water injection unit and a water outlet unit, a solid-liquid separator is integrated on the top of the crystallization granulation fluidized bed reactor, the seed delivery unit, the alkali solution delivery unit, the particle discharge unit and the concentrated water injection unit are all connected to the crystallization granulation fluidized bed reactor, the chemical delivery unit, the sludge discharge unit and the water outlet unit are all connected to the solid-liquid separator, and the water outlet unit is also connected to the acid delivery unit; the electrodialysis subsystem includes a bipolar membrane electrodialysis device 71, and the secondary reverse osmosis subsystem includes a secondary reverse osmosis device 81, and the bipolar membrane electrodialysis device 71 is respectively connected to the water outlet unit, the alkali solution delivery unit, the acid solution delivery unit and the secondary reverse osmosis device 81.

[0053] In this embodiment, the coarse seed particles rich in calcium carbonate and the concentrated sludge rich in magnesium hydroxide are recovered by the integrated fluidized bed subsystem for descaling, turbidity removal and organic matter removal, and are used as the desulfurizer and industrial raw material of the desulfurization system for comprehensive utilization; the electrodialysis subsystem is used to desalinate and recover the alkali solution and acid solution, which are used for fluidized bed descaling and effluent neutralization respectively; the effluent of the electrodialysis subsystem is treated by the secondary reverse osmosis subsystem to recover the clean water, and the concentrated water is utilized separately or returned to the enterprise wastewater treatment system.

[0054] Specifically, the crystallization granulation fluidized bed reactor includes a variable diameter cylinder 61, in which the alkali solution and the concentrated water are mixed and crystallized by convection effect; the variable diameter cylinder 61 is a venturi tube structure as a whole, the top of the variable diameter cylinder 61 is closed, and a plurality of water outlet holes are provided on the upper side wall thereof; the solid-liquid separator includes an annular mud discharge cylinder 41 arranged on the outer side of the upper part of the variable diameter cylinder 61, the bottom cross-section of the mud discharge cylinder 41 is "V"-shaped, and a partition 42 is arranged in the mud discharge cylinder 41, and the partition 42 divides the upper part of the inner cavity of the mud discharge cylinder 41 into a liquid inlet cavity and a liquid outlet cavity. A plurality of pipeline mixers 43 in a circular array are arranged on the upper part of the liquid inlet chamber, a plurality of inclined plates 44 are arranged at equal intervals on the upper part of the liquid outlet chamber, a swirl guide tube 4302 is arranged on the upper part of the mixing tube body 4301 of the pipeline mixer 43, and a spiral sheet 4303 is arranged on the lower part, and the swirl guide tube 4302 is connected to the water outlet hole on the variable diameter cylinder 61 through a connecting pipe, the connecting pipe is arranged obliquely, and the connecting pipe is tangentially connected to the water outlet hole and the swirl guide tube 4302; a guide plate 46 is also arranged in the mud discharge cylinder 41, and the guide plate 46 is located below the pipeline mixer 43. The variable diameter cylinder 61 of this embodiment is designed with reaction areas of different diameters, so that different areas in the fluidized bed have different rising flow rates, so that coarse seed particles rich in calcium carbonate of different particle sizes are suspended in different regions, and the newly formed calcium carbonate adsorbs organic matter, so as to achieve multiple functions of descaling, deturbidity removal, and organic matter removal.

[0055] Specifically, the seed delivery unit includes a seed mixing bucket 13, a seed delivery bucket 12 is arranged above the seed mixing bucket 13, a water inlet pump 11 is arranged on the water inlet pipe of the seed mixing bucket 13, the seed delivery bucket 12 is connected to the lower part of the variable diameter cylinder 61 through a seed delivery pipe 15, and a seed delivery pump 14 is arranged on the seed delivery pipe 15. The seed delivery bucket 12 is used to store fine-grained seeds, and the fine-grained seeds in the seed delivery bucket 12 are delivered to the seed mixing bucket 13 via a conveyor.

[0056] Specifically, the drug dosing unit includes a drug dosing tank 31 and a drug dosing pipe 34. The drug dosing pipe 34 includes a main pipe and a plurality of branch pipes connected to the main pipe. The drug dosing tank 31 is connected to the main pipe, and a drug dosing pump 32 and a drug dosing control valve 33 are arranged on the main pipe. The outlet end of the branch pipe extends into the upper inner part of the mixing pipe body 4301 of the corresponding pipeline mixer 43. The drug dosing tank 31 is used to store drugs. Multiple drug dosing tanks 31 can be arranged in parallel to store a variety of different drugs.

[0057] Specifically, the sludge discharge unit includes a sludge discharge pipe, which is connected to the bottom of the sludge discharge barrel 41, a sludge pump 47 is provided on the sludge discharge pipe, and a sludge collection tank 48 is provided below the outlet of the sludge discharge pipe; the particle discharge unit includes a particle discharge pipe, which is connected to the lower part of the variable diameter cylinder 61, a particle discharge valve 51 is provided on the particle discharge pipe, and a particle collection bucket 52 is provided below the outlet of the particle discharge pipe. The sludge collection tank 48 is used to collect concentrated sludge, and the particle collection bucket 52 is used to collect coarse seed particles.

[0058] Specifically, the concentrated water injection unit includes a concentrated water injection pipe, on which a pressure gauge 63 and a concentrated water pump 62 are arranged, the concentrated water injection pipe outlet is connected to a concentrated water distribution plate 64, the concentrated water distribution plate 64 is located in the lower part of the variable diameter cylinder 61, the concentrated water distribution plate 64 adopts a concave structure plate body, and a number of water distribution caps 6401 are evenly arranged on the concentrated water distribution plate 64; the alkali solution addition unit includes an alkali storage tank 21 and an alkali solution distribution plate 25, the alkali storage tank 21 is connected to the alkali solution distribution plate 25 through an alkali solution dosing pipe 24, an alkali solution pump 22 and an alkali solution dosing control valve 23 are arranged on the alkali solution dosing pipe 24, the alkali solution distribution plate 25 is located directly above the concentrated water distribution plate 64, and is arranged opposite to the concentrated water distribution plate 64, the alkali solution distribution plate 25 adopts a concave structure plate body, and a number of alkali solution nozzles 2501 are evenly arranged on the alkali solution distribution plate 25, and the liquid inlet of the alkali storage tank 21 is connected to the bipolar membrane electrodialysis device 71. The alkali solution distribution plate 25 and the concentrate water distribution plate 64 form focused convection. The strong convection effect causes the concentrate water and the alkali solution to be highly mixed in the focal area between the alkali solution distribution plate 25 and the concentrate water distribution plate 64, increasing the collision frequency and contact area between the fluids, thereby improving the reaction efficiency and mass transfer effect between the two, helping to promote the crystallization process in the local area, accelerating the precipitation of impurities in the concentrate water and the formation of particles, and further improving the concentrate water treatment efficiency.

[0059] Specifically, the water outlet unit includes a water outlet trough 65 and a water outlet pipe. The annular water outlet trough 65 is arranged at the upper end of the outer wall of the mud discharge cylinder 41. As the concentrated water and alkali solution are injected into the lower part of the variable diameter cylinder 61, the liquid level of the mixed liquid in the variable diameter cylinder 61 gradually rises until it flows through the water outlet hole of the variable diameter cylinder 61 through the connecting pipe through the pipeline mixer 43 and enters the mud discharge cylinder 41. The liquid level in the mud discharge cylinder 41 rises accordingly. After the mixed liquid level reaches the upper end of the mud discharge cylinder 41, it overflows into the water outlet trough 65. 5. The bottom of the water outlet tank 65 is connected to the bipolar membrane electrodialysis device 71 through the water outlet pipe. The mixed liquid in the water outlet tank 65 enters the bipolar membrane electrodialysis device 71 through the water outlet pipe. The water outlet pipe is provided with a pH real-time online detector 66 and an online turbidity detector 67. The acid dosing unit includes an acid storage tank 68. The acid storage tank 68 is connected to the water outlet pipe through an acid dosing pipe. An acid pump 69 is provided on the acid dosing pipe. The liquid inlet of the acid storage tank 68 is connected to the bipolar membrane electrodialysis device 71.

[0060] Example 2

[0061] Please refer to the attached Figure 6 As shown, this embodiment provides a method for cleaning and treating concentrated water from a reverse osmosis, which is treated by the system for cleaning and treating concentrated water from a reverse osmosis of embodiment 1, and specifically includes:

[0062] The reverse osmosis concentrated water is sent to the crystallization granulation fluidized bed reactor through the concentrated water injection unit, and then the alkali solution, fine crystal seeds and reagents are respectively added through the alkali solution addition unit, the seed crystal addition unit and the reagent addition unit. During the operation of the crystallization granulation fluidized bed reactor, the coarse crystal seed particles rich in calcium carbonate and the concentrated sludge rich in magnesium hydroxide are respectively recovered through the particle discharge unit and the sludge discharge unit. The coarse crystal seed particles rich in calcium carbonate are sent to the wastewater desulfurization system for wastewater desulfurization, and the concentrated sludge rich in magnesium hydroxide is sent to the reprocessing link as an industrial raw material;

[0063] The concentrated water treated by the integrated fluidized bed subsystem for descaling, turbidity removal and organic matter removal is sent to the electrodialysis subsystem through the water outlet unit for desalination and recovery of alkali solution and acid solution, and the alkali solution and acid solution are sent to the alkali storage tank 21 and the acid storage tank 68 respectively;

[0064] The effluent from the electrodialysis subsystem is sent to the secondary reverse osmosis subsystem for treatment, the secondary reverse osmosis clean water is reused, and the secondary reverse osmosis concentrated water enters the water inlet of the enterprise's wastewater treatment system, or is directly used according to quality.

[0065] Specifically, the fine-grained seed crystals are at least one of garnet, quartz, and calcium carbonate particles with a particle size of 60 to 800 meshes; preferably, the fine-grained seed crystals are garnet particles with a particle size of 60 to 100 meshes.

[0066] Specifically, the alkali solution added to the crystallization granulation fluidized bed reactor is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, calcium hydroxide, and calcium bicarbonate, and the amount used is such that the pH value in the crystallization granulation fluidized bed reactor is between 9.5 and 11.0; preferably, the alkali solution added to the crystallization granulation fluidized bed reactor is at least one of sodium hydroxide and sodium carbonate, and the amount used is such that the pH value in the crystallization granulation fluidized bed reactor is between 10.0 and 11.0.

[0067] Specifically, the reagent includes flocculant and powdered activated carbon. The flocculant is at least one of polyaluminum chloride and hydrolyzed polyacrylamide. The amount of polyaluminum chloride is 100-500 mg / L, and the amount of hydrolyzed polyacrylamide is 0-5 mg / L. The amount of flocculant is automatically adjusted according to the online detection result of the effluent turbidity by the online turbidity detector 67; the amount of powdered activated carbon is 0-500 mg / L, so that the effluent CODCr value is less than 100 mg / L, and the amount of powdered activated carbon is adjusted according to the concentration of organic matter in the effluent of the crystallization granulation fluidized bed reactor.

[0068] Specifically, the removal time of the coarse seed particles is determined according to the online detection result of the water inlet pressure gauge 63. The coarse seed particles are particles with a particle size of 2 to 3 mm and a calcium carbonate content higher than 95%.

[0069] Specifically, the concentrated sludge collected in the sludge collection tank 48 has a moisture content of 82-87% and a magnesium hydroxide content higher than 80%.

[0070] Example 3

[0071] The system of Example 1 and the method of Example 2 are used to treat the reverse osmosis concentrated water of the steel industry, and the process design treatment capacity is 30m 3 / h.

[0072] After testing, the total hardness of the steel industry reverse osmosis concentrated water was 1816.88 mg / L, the total alkalinity was 930.56 mg / L, the calcium ion content was 537.81 mg / L, the magnesium ion content was 107.56 mg / L, the chromaticity was 500, and the CODCr content was 180.17 mg / L.

[0073] Adjust the water inlet flow to 10.3m 3 / h, at this time, the average upward flow rate in the crystallization granulation fluidized bed reactor is 80m / h, alkali solution (NaOH) is added to make the pH value in the crystallization granulation fluidized bed reactor 10.85, and the dosage of flocculant (PAC) is 350mg / L. The fine-grained seed is 60-80 mesh garnet, 65L of garnet is added, and the seed is discharged and added every 40h.

[0074] After testing, the total hardness of the effluent from the crystallization granulation fluidized bed reactor was 315.98 mg / L, with a removal rate of 82.61%; the calcium ion was 78.43 mg / L, with a removal rate of 85.42%; the magnesium ion was 28.23 mg / L, with a removal rate of 73.75%; the chromaticity removal rate was 99.60%; the CODCr concentration was 80.79 mg / L, with a removal rate of 55.16%; after coagulation and solid-liquid separation, the effluent turbidity dropped to 0.87 NTU, and the effluent pH was 8 after acid neutralization.

[0075] In this embodiment, the bipolar membrane electrodialysis device 71 is of TWED-32-62S type, the positive membrane is TWDDC2 type, the negative membrane is TWDDA35, the bipolar membrane is TWEDBM type, the membrane logarithm is 60, the alkali concentration is 1.348mol / L, the acid concentration is 1.064mol / L, and the acid chamber product is a mixed acid composed of HCl, H2SO4 and HNO3, with a purity of HCl of 92%. Part of the alkali solution is recycled to the alkali storage tank 21, and part of the acid solution is recycled to the acid storage tank 68 to adjust the pH value of the effluent, and the remaining alkali solution and acid solution are used in other processes.

[0076] The effluent from the electrodialysis subsystem enters the secondary reverse osmosis subsystem for treatment. The secondary reverse osmosis subsystem uses the LCLEPRO-4040 membrane element purchased from DuPont, with a desalination rate of 99.5%. The secondary reverse osmosis subsystem recovery rate reaches 75%, and the daily concentrated water volume is 180t. The total hardness of the discharged concentrated water is 710.20mg / L. The final treatment method of the concentrated water from the secondary reverse osmosis subsystem is that 50% of the concentrated water is used for slag flushing in blast furnaces of steel enterprises, and 50% is returned to the coking wastewater treatment system.

[0077] Normally, pure calcium carbonate crystals appear white, while the coarse-grained seed crystals rich in calcium carbonate discharged in this embodiment have a particle size of 2-3 mm and are light yellow in color. Figure 7 Combined with the above test results, it is found that the crystallization process in the present invention can remove part of the colored substances.

[0078] Example 4

[0079] The system of Example 1 and the method of Example 2 are used to treat reverse osmosis concentrated water in the printing and dyeing industry, and the process design treatment capacity is 45m 3 / h.

[0080] After testing, the total hardness of the reverse osmosis concentrated water from the printing and dyeing industry was 760.52 mg / L, the total alkalinity was 870.36 mg / L, the calcium ion content was 240.81 mg / L, the magnesium ion content was 38.39 mg / L, the chromaticity was 150, and the CODCr content was 216.15 mg / L.

[0081] Adjust the water inlet flow to 11.5m 3 / h, at this time, the average rising velocity in the fluidized bed is 80m / h, alkali solution (NaOH) is added to make the pH value 10.50, the addition amount of flocculant (PAC) is 150mg / L, the addition amount of hydrolyzed polyacrylamide (PAM) is 1.25mg / L, and the amount of powdered activated carbon is 80mg / L. The fine-grained seed is 60-80 mesh garnet seed, 98L garnet is added, and the seed is discharged and added every 40h.

[0082] After testing, the total hardness of the effluent from the crystallization granulation fluidized bed reactor was 113.60 mg / L, with a removal rate of 86.95%; the calcium ion was 11.56 mg / L, with a removal rate of 95.20%; the magnesium ion was 17.35 mg / L, with a removal rate of 54.81%; the chromaticity removal rate reached 99.20%; the CODCr concentration was 62.15 mg / L, with a removal rate of 71.25%; after coagulation and solid-liquid separation, the effluent turbidity dropped to 0.82 NTU, and the effluent pH value was 8 after acid neutralization.

[0083] In this embodiment, the bipolar membrane electrodialysis device 71 is of TWED-32-62S type, the positive membrane is TWDDC2 type, the negative membrane is TWDDA35, the bipolar membrane is TWEDBM type, the membrane logarithm is 60, the alkali concentration is 1.100 mol / L, the acid concentration is 1.023 mol / L, the acid chamber product is a mixed acid composed of HCl, H2SO4 and HNO3, and the purity of HCl is 91%. Part of the alkali solution is recycled to the alkali storage tank 21, part of the acid solution is recycled to the acid storage tank 68, and the remaining alkali solution and acid solution are used in other processes.

[0084] The effluent from the electrodialysis subsystem enters the secondary reverse osmosis subsystem for treatment. The secondary reverse osmosis subsystem uses LCLEPRO-4040 membrane elements purchased from DuPont, with a desalination rate of 99.5%. The recovery rate of the secondary reverse osmosis subsystem reaches 85%, and the daily amount of brine produced is 270t. The total hardness of the discharged brine is 755.80mg / L. All the brine from the secondary reverse osmosis subsystem is returned to the printing and dyeing wastewater treatment system.

[0085] The above description is a further detailed description of the present invention in combination with a specific preferred embodiment, and it cannot be determined that the specific implementation of the present invention is limited to the above description. For ordinary technicians in the technical field of the present invention, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should all fall within the scope of protection of the present invention.

Claims

1. A reverse osmosis concentrated water cleaning treatment system, characterized in that: It includes a fluidized bed subsystem for descaling, turbidity removal and organic matter removal, an electrodialysis subsystem and a secondary reverse osmosis subsystem which are arranged in sequence; The scale, turbidity and organic matter removal integrated fluidized bed subsystem comprises a crystallization granulation fluidized bed reactor, a crystal seed delivery unit, an alkali solution delivery unit, a reagent delivery unit, a particle discharge unit, a sludge discharge unit, a concentrated water injection unit and a water outlet unit. A solid-liquid separator is integrated on the top of the crystallization granulation fluidized bed reactor. The crystal seed delivery unit, the alkali solution delivery unit, the particle discharge unit and the concentrated water injection unit are all connected to the crystallization granulation fluidized bed reactor. The reagent delivery unit, the sludge discharge unit and the water outlet unit are all connected to the solid-liquid separator. The water outlet unit is also connected to the acid delivery unit. The crystallization granulation fluidized bed reactor comprises a variable diameter cylinder, in which the alkali solution and the concentrated water are mixed and crystallized by convection effect; The electrodialysis subsystem includes a bipolar membrane electrodialysis device, and the secondary reverse osmosis subsystem includes a secondary reverse osmosis device. The bipolar membrane electrodialysis device is respectively connected to the water outlet unit, the alkali solution addition unit, the acid solution addition unit, and the secondary reverse osmosis device.

2. A reverse osmosis concentrated water cleaning treatment system as claimed in claim 1, characterized in that: The reducer cylinder as a whole is a Venturi tube structure, the top of the reducer cylinder is closed, and a plurality of water outlet holes are provided on its upper side wall. The solid-liquid separator includes an annular mud discharge cylinder arranged on the outer side of the upper part of the reducer cylinder, and the bottom cross-section of the mud discharge cylinder is "V"-shaped. A partition is arranged in the mud discharge cylinder, and the partition divides the upper part of the inner cavity of the mud discharge cylinder into a liquid inlet cavity and a liquid outlet cavity. A plurality of pipeline mixers in a circular array are arranged on the upper part of the liquid inlet cavity, and a plurality of inclined plates are equidistantly arranged on the upper part of the liquid outlet cavity. A swirl guide pipe is arranged on the upper part of the mixing tube body of the pipeline mixer, and a spiral sheet is arranged on the lower part. The swirl guide pipe is connected to the water outlet hole on the reducer cylinder through a connecting pipe. The connecting pipe is arranged obliquely, and the connecting pipe is tangentially connected to the water outlet hole and the swirl guide pipe. A guide plate is also arranged in the mud discharge cylinder, and the guide plate is located below the pipeline mixer.

3. A reverse osmosis concentrated water cleaning treatment system as claimed in claim 2, characterized in that: The crystal seed delivery unit comprises a crystal seed mixing bucket, a crystal seed delivery bucket is arranged above the crystal seed mixing bucket, a water inlet pump is arranged on the water inlet pipe of the crystal seed mixing bucket, the crystal seed delivery bucket is connected to the lower part of the variable diameter cylinder through a crystal seed delivery pipe, and a crystal seed delivery pump is arranged on the crystal seed delivery pipe; the pharmaceutical dosing unit comprises a dosing tank and a pharmaceutical dosing pipe, the pharmaceutical dosing pipe comprises a main pipe and a plurality of branch pipes connected to the main pipe, the dosing tank is connected to the main pipe, a dosing pump and a pharmaceutical dosing control valve are arranged on the main pipe, and an outlet end of the branch pipe is provided with a dosing pump and a pharmaceutical dosing control valve. The water outlet unit includes a water outlet trough and a water outlet pipe. The annular water outlet trough is arranged at the upper end of the outer wall of the mud discharge tube. The water outlet trough is connected to the bipolar membrane electrodialysis device through the water outlet pipe. The water outlet pipe is provided with a real-time online pH detector and an online turbidity detector. The acid dosing unit includes an acid storage tank. The acid storage tank is connected to the water outlet pipe through an acid dosing pipe. An acid pump is arranged on the acid dosing pipe. The liquid inlet of the acid storage tank is connected to the bipolar membrane electrodialysis device.

4. A reverse osmosis concentrated water cleaning treatment system as claimed in claim 3, characterized in that: The sludge discharge unit includes a sludge discharge pipe, which is connected to the bottom of the sludge discharge cylinder, a sludge pump is arranged on the sludge discharge pipe, and a sludge collection tank is arranged below the outlet of the sludge discharge pipe; the particle discharge unit includes a particle discharge pipe, which is connected to the lower part of the variable diameter cylinder, a particle discharge valve is arranged on the particle discharge pipe, and a particle collection bucket is arranged below the outlet of the particle discharge pipe.

5. A reverse osmosis concentrated water cleaning treatment system as claimed in claim 4, characterized in that: The concentrated water injection unit comprises a concentrated water injection pipe, on which a pressure gauge and a concentrated water pump are arranged, the concentrated water injection pipe outlet is connected to a concentrated water distribution plate, the concentrated water distribution plate is located in the lower inner part of the variable diameter cylinder, the concentrated water distribution plate adopts a concave structure plate body, and a plurality of water distribution caps are evenly arranged on the concentrated water distribution plate; the alkali solution adding unit comprises an alkali storage tank and an alkali solution distribution plate, the alkali storage tank is connected to the alkali solution distribution plate through an alkali solution dosing pipe, an alkali solution pump and an alkali solution dosing control valve are arranged on the alkali solution distribution plate, the alkali solution distribution plate is located directly above the concentrated water distribution plate and is arranged opposite to the concentrated water distribution plate, the alkali solution distribution plate adopts a concave structure plate body, a plurality of alkali solution nozzles are evenly arranged on the alkali solution distribution plate, and the liquid inlet of the alkali storage tank is connected to the bipolar membrane electrodialysis device.

6. A method for cleaning and treating concentrated water from a reverse osmosis, using the system for cleaning and treating concentrated water from a reverse osmosis according to any one of claims 1 to 5, characterized in that: Specifically include: (1) The reverse osmosis concentrated water is fed into a crystallization granulation fluidized bed reactor through a concentrated water injection unit, and then the alkali solution, fine crystal seeds, and reagents are respectively fed through an alkali solution feeding unit, a seed feeding unit, and a reagent feeding unit. During the operation of the crystallization granulation fluidized bed reactor, the coarse crystal seed particles rich in calcium carbonate and the concentrated sludge rich in magnesium hydroxide are respectively recovered through a particle discharge unit and a sludge discharge unit. The coarse crystal seed particles rich in calcium carbonate are sent to a wastewater desulfurization system for wastewater desulfurization, and the concentrated sludge rich in magnesium hydroxide is sent to a reprocessing link as an industrial raw material; (2) The concentrated water treated by the integrated fluidized bed subsystem for descaling, turbidity removal and organic matter removal is sent to the electrodialysis subsystem through the water outlet unit for desalination and recovery of alkali and acid. The alkali and acid are sent to the alkali storage tank and acid storage tank respectively; (3) The effluent from the electrodialysis subsystem is sent to the secondary reverse osmosis subsystem for treatment. The secondary reverse osmosis clean water is reused, and the secondary reverse osmosis concentrated water enters the water inlet of the enterprise's wastewater treatment system, or is directly used according to quality.

7. A method for cleaning and treating concentrated reverse osmosis water according to claim 6, characterized in that: The fine-grained seed crystals are garnet particles with a particle size of 60 to 100 meshes.

8. A method for cleaning and treating concentrated reverse osmosis water according to claim 6, characterized in that: The alkali solution added to the crystallization granulation fluidized bed reactor is at least one of sodium hydroxide and sodium carbonate, and the amount thereof is such that the pH value in the crystallization granulation fluidized bed reactor is between 10.0 and 11.

0.

9. A method for cleaning and treating reverse osmosis concentrated water according to claim 6, characterized in that: The reagents include flocculants and powdered activated carbon. The flocculant is at least one of polyaluminium chloride and hydrolysed polyacrylamide. The dosage of polyaluminium chloride is 100-500 mg / L, and the dosage of hydrolysed polyacrylamide is 0-5 mg / L. The dosage of the flocculant is automatically adjusted according to the online detection result of the effluent turbidity by the online turbidity detector. The dosage of the powdered activated carbon is 0-500 mg / L, so that the effluent CODCr value is less than 100 mg / L. The dosage of the powdered activated carbon is adjusted according to the concentration of organic matter in the effluent of the crystallization granulation fluidized bed reactor.

10. A method for cleaning and treating concentrated reverse osmosis water according to claim 6, characterized in that: According to the online detection result of the water inlet pressure gauge, the removal time of the coarse seed particles is determined. The coarse seed particles are particles with a particle size of 2 to 3 mm and a calcium carbonate content higher than 95%.

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