Process system for recycling electroplating comprehensive wastewater

Abstract

The utility model provides a process system for recycling electroplating comprehensive wastewater, which relates to the technical field of wastewater treatment and is characterized in that a liquid inlet of a primary electrodeionization device is communicated with a primary wastewater treatment unit, and a fresh water outlet of the primary electrodeionization device is communicated with a secondary wastewater treatment unit; a concentrated water outlet of the first-stage electrodeionization device is communicated with the second-stage electrodeionization device; a fresh water outlet of the secondary electrodeionization device is communicated with the primary electrodeionization treatment device, and a concentrated water outlet of the secondary electrodeionization device is communicated with the solid-liquid separation device; a liquid outlet of the solid-liquid separation device is communicated with the evaporation device; the evaporation device comprises a condensed water outlet and a byproduct salt outlet, and the condensed water outlet is communicated with the secondary wastewater treatment unit; a produced water outlet of the secondary wastewater treatment unit is communicated with the produced water collecting tank; a waste liquid outlet of the second-stage wastewater treatment unit is communicated with a second-stage electrodeionization device, so that pollutants such as heavy metal ions and organic matters in wastewater can be removed, and cyclic utilization of water resources and recovery of salt resources are realized.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment, in particular to a process system for resource utilization of comprehensive electroplating wastewater. Background Art

[0002] Electroplating is a process that utilizes the principle of electrolysis to plate a thin layer of other metals or alloys on certain metal surfaces. It is a process that utilizes electrolysis to adhere a layer of metal film to the surface of metal or other material parts, thereby preventing metal oxidation (such as rust), improving wear resistance, conductivity, reflectivity, corrosion resistance (copper sulfate, etc.), and enhancing aesthetics. Electroplating wastewater contains many types of highly toxic substances, which are very harmful. Untreated electroplating wastewater that does not meet standards is discharged into rivers and seeps into the ground, which not only harms the environment, but also pollutes drinking water and industrial water. Therefore, electroplating wastewater must be strictly controlled and properly handled. However, the treatment process of existing electroplating wastewater treatment devices is cumbersome and the treatment efficiency is low, making it difficult to meet the demand for electroplating wastewater treatment.

[0003] In the current electroplating wastewater treatment process, the amount of wastewater after front-end treatment is large, and it is discharged directly after simple sand filtration and carbon filtration. The wastewater treatment is incomplete. On the one hand, the electroplating wastewater contains more salt and other harmful substances, and direct discharge will cause pollution. On the other hand, discharging electroplating wastewater will waste a lot of water resources. The current electroplating wastewater recovery process cannot achieve effective recycling of water resources and salt. Utility Model Content

[0004] The purpose of this utility model is to provide a process system for the resource utilization of comprehensive electroplating wastewater to solve the problems existing in the above-mentioned prior art. The primary wastewater treatment unit performs primary purification treatment, and the secondary electric desalination device performs secondary desalination treatment on the primary concentrated water to produce secondary concentrated water. The industrial by-product salt is produced through the solid-liquid separation device and the evaporation device, thereby realizing the effective recovery of salt in the electroplating wastewater. The secondary fresh water obtained by the secondary electric desalination device is then introduced into the primary desalination device for circulation treatment. The secondary wastewater treatment unit purifies the primary fresh water and condensed water, and the purified water obtained can be used in the production line as pure water to realize the recovery of water resources. This effectively realizes the recycling of water resources and the recovery of salt resources in electroplating wastewater.

[0005] In order to achieve the above-mentioned purpose, the present invention provides the following scheme: a process system for the resource utilization of comprehensive electroplating wastewater is provided, comprising a primary wastewater treatment unit, an electric desalination treatment unit and a secondary wastewater treatment unit, wherein the electric desalination treatment unit comprises a primary electric desalination device, a secondary electric desalination device, a solid-liquid separation device and an evaporation device, the liquid inlet of the primary electric desalination device is connected to the waste liquid outlet of the primary wastewater treatment unit, the fresh water outlet of the primary electric desalination device is connected to the secondary wastewater treatment unit, the concentrated water outlet of the primary electric desalination device is connected to the secondary electric desalination device the liquid inlet of the secondary electric desalination device is connected; the fresh water outlet of the secondary electric desalination device is connected to the liquid inlet of the primary electric desalination device, and the concentrated water outlet of the secondary electric desalination device is connected to the liquid inlet of the solid-liquid separation device; the liquid outlet of the solid-liquid separation device is connected to the liquid inlet of the evaporation device; the evaporation device includes a condensed water outlet and a by-product salt outlet, and the condensed water outlet is connected to the secondary wastewater treatment unit; the produced water outlet of the secondary wastewater treatment unit is connected to the produced water collection tank; the waste liquid outlet of the secondary wastewater treatment unit is connected to the liquid inlet of the secondary electric desalination device.

[0006] Preferably, the electro-dionization treatment unit includes a concentrate pretreatment device, the liquid inlet of the concentrate pretreatment device is connected to the concentrate outlet of the secondary electro-dionization device, the liquid outlet of the concentrate pretreatment device is connected to the liquid inlet of the solid-liquid separation device, and the concentrate pretreatment device includes a second reaction tank, a second flocculation tank, a second coagulant aid tank, and a second sedimentation tank that are connected in sequence; the second reaction tank, the second flocculation tank, and the second coagulant aid tank are all equipped with mechanical agitators.

[0007] Preferably, the solid-liquid separation device is an immersed membrane filtration device, and the immersed membrane filtration device includes a curtain filter membrane for filtering wastewater.

[0008] Preferably, the membrane material of the curtain filter membrane is polyvinylidene fluoride, and the base layer of the membrane sheet is PET non-woven fabric.

[0009] Preferably, the secondary wastewater treatment unit includes a low-pressure reverse osmosis device, an oxidation treatment device and a second medium-pressure reverse osmosis device, the liquid inlet of the low-pressure reverse osmosis device is connected to the fresh water outlet of the first-level electro-dimium ionization device; the produced water outlet of the low-pressure reverse osmosis device is connected to the produced water collection tank, and the waste liquid outlet of the low-pressure reverse osmosis device is connected to the liquid inlet of the oxidation treatment device; the liquid inlet of the oxidation treatment device is also connected to the condensed water outlet of the evaporation device; the liquid outlet of the oxidation treatment device is connected to the liquid inlet of the second medium-pressure reverse osmosis device, the produced water outlet of the second medium-pressure reverse osmosis device is connected to the produced water collection tank, and the waste liquid outlet of the second medium-pressure reverse osmosis device is connected to the secondary electro-dimium ionization device.

[0010] Preferably, the primary electro-desalination device and the secondary electro-desalination device both include electrodialysis equipment, and the oxidation treatment device includes a two-dimensional electrocatalytic oxidation device.

[0011] Preferably, an ultrafiltration device is connected between the oxidation treatment device and the second medium-pressure reverse osmosis device, the liquid inlet of the ultrafiltration device is connected to the outlet of the oxidation treatment device, the clean water outlet of the ultrafiltration device is connected to the second medium-pressure reverse osmosis device, and the waste liquid outlet of the ultrafiltration device is connected to the liquid inlet of the oxidation treatment device.

[0012] Preferably, the primary wastewater treatment unit includes a pretreatment device, a biochemical treatment device, a sterilization and disinfection tank device and a first medium-pressure reverse osmosis device connected in sequence; the produced water outlet on the first medium-pressure reverse osmosis device is connected to the produced water collection tank; the waste liquid outlet of the first medium-pressure reverse osmosis device is connected to the liquid inlet of the primary electric desalination device.

[0013] Preferably, the pretreatment device includes a first neutralization reaction tank, a first cyanide destruction tank, a first flocculation sedimentation tank, and a sludge concentration tank connected in sequence. The sludge concentration tank is connected to a filter press, and the filtrate outlet of the filter press is connected to the liquid inlet of the biochemical treatment device.

[0014] Preferably, the filter press is a plate and frame filter press.

[0015] Compared with the prior art, the utility model has achieved the following technical effects:

[0016] The primary wastewater treatment unit of the present invention first performs a primary purification treatment on the electroplating wastewater, and then passes the wastewater into the electric desalination treatment unit. The primary electric desalination device performs a primary desalination treatment on the wastewater, and the salt in the electroplating wastewater is concentrated in the primary stage to produce primary fresh water and primary concentrated water. The secondary electric desalination device performs a secondary desalination treatment on the primary concentrated water, and the salt in the primary concentrated water is concentrated twice to produce secondary concentrated water. The secondary concentrated water is subjected to solid-liquid separation by the solid-liquid separation device, and then evaporated in the evaporation device to produce industrial by-product salt, thereby achieving effective recovery of salt in the electroplating wastewater. The secondary fresh water obtained by the secondary electric desalination device is then passed into the primary desalination device for circulation treatment. The primary fresh water produced by the primary electric desalination device and the condensed water produced by the evaporation device are then purified by the secondary wastewater treatment unit. The purified water obtained can be used as pure water in the production line, thereby achieving water resource recovery. That is, the present invention effectively realizes the recycling of water resources and the recovery of salt resources in electroplating wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a schematic diagram of the process system for resource utilization of comprehensive electroplating wastewater in this utility model;

[0019] Figure 2 This is a schematic diagram of the primary wastewater treatment unit of the utility model;

[0020] Figure 3 This is a schematic diagram of the electric desalination treatment unit of the utility model;

[0021] Figure 4 This is a schematic diagram of the secondary wastewater treatment unit of the utility model. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0024] Please refer to Figures 1 to 4As shown, in this embodiment, a process system for recycling electroplating comprehensive wastewater is provided, which includes a primary wastewater treatment unit, an electric desalination treatment unit and a secondary wastewater treatment unit. The liquid inlet of the primary wastewater treatment unit is connected to the electroplating wastewater collection device. The electric desalination treatment unit includes a primary electric desalination device, a secondary electric desalination device, a solid-liquid separation device and an evaporation device. The liquid inlet of the primary electric desalination device is connected to the waste liquid outlet of the primary wastewater treatment unit. The salt water can be desalinated by the primary electric desalination device. The primary electric desalination device includes a fresh water outlet and a concentrated water outlet. The fresh water outlet of the primary electric desalination device is connected to the waste liquid outlet of the primary wastewater treatment unit. The outlet is connected to a liquid inlet of the secondary wastewater treatment unit, the concentrate outlet of the primary electro-deionizer is connected to the liquid inlet of the secondary electro-deionizer, and the secondary electro-deionizer is capable of desalinating salt water. The secondary electro-deionizer includes a fresh water outlet and a concentrate outlet. The fresh water outlet of the secondary electro-deionizer is connected to the liquid inlet of the primary electro-deionizer, and the concentrate outlet of the secondary electro-deionizer is connected to the liquid inlet of the solid-liquid separation device. The solid-liquid separation device includes a liquid outlet and a sludge outlet. The liquid outlet of the solid-liquid separation device is connected to the liquid inlet of the evaporation device. The sludge separated by the solid-liquid separation device is discharged from the sludge outlet. The evaporation device includes a condensate outlet and a by-product salt outlet. The evaporation device is preferably an MVR (mechanical vapor recompression) evaporator, which uses MVR technology to evaporate the liquid discharged from the solid-liquid separation device. The MVR evaporator is a new type of high-efficiency and energy-saving evaporation equipment. The MVR system is driven by electricity and utilizes the secondary steam and its energy generated by the evaporation of the material itself. It is compressed by a steam compressor to perform work, increasing the enthalpy of the secondary steam, which is then sent to the heating chamber as a heating heat source. The MVR evaporator includes a heat exchanger, a circulating pump, a separator, a heater, and a compressor. It uses low-temperature and low-pressure steaming technology and clean energy to generate steam, separating water from the medium. The MVR evaporator can perform evaporation, concentration, and crystallization during the production process. The condensate outlet of the evaporation device is connected to an inlet of the secondary wastewater treatment unit. The secondary wastewater treatment unit includes a produced water outlet and a waste liquid outlet. The produced water outlet of the secondary wastewater treatment unit is connected to the produced water collection tank, and the waste liquid outlet of the secondary wastewater treatment unit is connected to the inlet of the secondary electro-deionization device.

[0025] Working principle:

[0026] S1. The electroplating wastewater in the electroplating wastewater collection device is transported to the primary wastewater treatment unit, and the electroplating wastewater is subjected to primary treatment by the primary wastewater treatment unit. Specifically, the primary treatment can effectively remove metal ions, ammonia nitrogen, phosphorus, etc. in the electroplating wastewater, fully remove organic matter in the electroplating wastewater, and perform sterilization, disinfection and filtration.

[0027] S2. After the primary treatment of the electroplating wastewater is completed, the wastewater (concentrated water) produced by the primary wastewater treatment unit flows into the electric desalination treatment unit, specifically directly into the primary electric desalination device, through which the wastewater is concentrated by the primary electric desalination device to desalinate the wastewater. The primary electric desalination device can produce primary fresh water and primary concentrated water. The primary fresh water produced by the primary electric desalination device is passed into the secondary wastewater treatment unit for purification treatment. The primary concentrated water produced by the primary electric desalination device is passed into the secondary electric desalination device, through which the primary concentrated water is further concentrated by the secondary electric desalination device to desalinate the primary concentrated water. The secondary electric desalination device can produce secondary fresh water and secondary concentrated water. The secondary fresh water produced by the secondary electric desalination device can be passed back into the primary electric desalination device, through which the secondary fresh water is further concentrated by the primary electric desalination device to desalinate the secondary fresh water. Specifically, the conductivity of the primary fresh water is controlled to be less than 2000 us / cm, and the conductivity of the secondary concentrated water is controlled to be greater than 80000 us / cm. The secondary concentrated water produced by the secondary electric desalination device is passed into the solid-liquid separation device, and the secondary concentrated water is filtered by the solid-liquid separation device. The sludge obtained by the solid-liquid separation device is discharged from the sludge outlet. The filtrate filtered out of the solid-liquid separation device is passed into the evaporation device. The evaporation device can evaporate, concentrate and crystallize the filtrate. The condensed water obtained by the evaporation device is discharged from the condensed water outlet to the secondary wastewater treatment unit. The solid phase obtained by the evaporation device is discharged from the by-product salt outlet to obtain industrial by-product salt, thereby realizing the recovery of salt resources in electroplating wastewater. The quality of industrial by-product salt refers to the content of sulfate and chloride being above 95%, the moisture content being below 5%, and the industrial by-product salt containing copper <0.003%, nickel <0.003%, chromium <0.003%, zinc <0.02%, iron <0.05%, aluminum <0.1% and cadmium <0.0004%.

[0028] S3, the secondary wastewater treatment unit treats the primary fresh water and condensate water respectively, and can purify the produced water. The produced water has the following indicators: copper <0.02mg / L, nickel <0.01mg / L, total chromium <0.1mg / L, zinc <0.05mg / L, iron <0.1mg / L, aluminum <0.08mg / L, cadmium <0.001mg / L, silver <0.01mg / L, lead <0.001mg / L, mercury <0.0001mg / L, total nitrogen <5.0mg / L, total phosphorus <0.2mg / L, COD <50mg / L, and conductivity <200uS / cm. The water outlet of the secondary wastewater treatment unit is used to discharge the produced water and is connected to the produced water collection pool. The produced water can be used in the production line. The wastewater (concentrated water) produced by the secondary wastewater treatment unit is returned to the secondary electric desalination device in step S2 for salt concentration treatment, and the wastewater is desalinated again to realize the circulation of the system.

[0029] The primary wastewater treatment unit of the present invention first performs a primary purification treatment on the electroplating wastewater, and then passes the wastewater into the electric desalination treatment unit. The primary electric desalination device performs a primary desalination treatment on the wastewater, and the salt in the electroplating wastewater is concentrated in the primary stage to produce primary fresh water and primary concentrated water. The secondary electric desalination device performs a secondary desalination treatment on the primary concentrated water, and the salt in the primary concentrated water is concentrated twice to produce secondary concentrated water. The secondary concentrated water is subjected to solid-liquid separation by the solid-liquid separation device, and then evaporated in the evaporation device to produce industrial by-product salt, thereby achieving effective recovery of salt in the electroplating wastewater. The secondary fresh water obtained by the secondary electric desalination device is then passed into the primary desalination device for circulation treatment. The primary fresh water produced by the primary electric desalination device and the condensed water produced by the evaporation device are then purified by the secondary wastewater treatment unit. The purified water obtained can be used as pure water in the production line, thereby achieving water resource recovery. That is, the present invention effectively realizes the recycling of water resources and the recovery of salt resources in electroplating wastewater.

[0030] In one embodiment, Figures 1 to 4 As shown, the electro-desalination unit also includes a concentrate pretreatment device. The concentrate pretreatment device's inlet is connected to the concentrate outlet of the secondary electro-desalination device, and its outlet is connected to the inlet of the solid-liquid separation device. The concentrate pretreatment device includes a second reaction tank, a second flocculation tank, a second coagulant-assisted tank, and a second sedimentation tank, which are connected in sequence. Mechanical agitators are installed in each of the second reaction tank, the second flocculation tank, and the second coagulant-assisted tank to enhance the treatment efficiency of the secondary concentrate. The second sedimentation tank is connected to the sludge thickening tank. Flocculants are added to the second flocculation tank to reduce wastewater turbidity and color and remove various high-molecular-weight substances, organic matter, certain heavy metal poisons, and radioactive substances. Chemicals are added to the wastewater to destabilize colloidal suspended particles or emulsions that are difficult to precipitate. These particles then aggregate or coalesce due to collision, forming larger particles or flocs. This allows the pollutants to sink or float naturally for removal. Coagulant-assisted reactions occur in the second coagulant-assisted tank. The secondary concentrated water produced by the secondary electro-desalination device is transported to the concentrate pretreatment device, where the residual metal ions, phosphorus, fluoride, suspended matter, etc. are reacted to form finer flocs.

[0031] In one embodiment, Figures 1 to 4As shown, the solid-liquid separation device is an immersed membrane filtration device, which includes a curtain filter membrane. Specifically, several membrane sheets are connected in parallel between two water pipes, forming a curtain structure. The membrane is immersed in contaminated water. After the contaminated water is filtered by the membrane sheets, the purified water can be discharged through the water pipe for reuse. The curtain filter membrane is a hollow fiber curtain immersion membrane assembly. In this solution, the curtain filter membrane (membrane sheet) uses a composite membrane structure made of PVDF (polyvinylidene fluoride) and a PET non-woven fabric base layer, ensuring the membrane's physical strength and chemical stability.

[0032] In one embodiment, Figures 1 to 4 As shown, the secondary wastewater treatment unit includes a low-pressure reverse osmosis device, an oxidation treatment device, and a second medium-pressure reverse osmosis device connected in sequence. The liquid inlet of the low-pressure reverse osmosis device is connected to the fresh water outlet of the first-stage electro-deionization device, the product water outlet of the low-pressure reverse osmosis device is connected to the product water collection tank, the waste liquid (concentrated water) outlet of the low-pressure reverse osmosis device is connected to the liquid inlet of the oxidation treatment device, the condensed water outlet of the evaporation device is connected to the liquid inlet of the oxidation treatment device, the liquid outlet of the oxidation treatment device is connected to the second medium-pressure reverse osmosis device, the second medium-pressure reverse osmosis device includes a product water outlet and a waste liquid (concentrated water) outlet, the product water outlet of the second medium-pressure reverse osmosis device is connected to the product water collection tank, and the waste liquid (concentrated water) outlet of the second medium-pressure reverse osmosis device is connected to the secondary electro-deionization device. In the second medium-pressure reverse osmosis device, the waste liquid undergoes medium-pressure reverse osmosis 2. The low-pressure reverse osmosis device and the second medium-pressure reverse osmosis device are both reverse osmosis devices, which include components such as a water pump, a reverse osmosis membrane element, a membrane shell, pneumatic components, and a bracket.

[0033] In this embodiment, if Figures 1 to 4 As shown, both the primary and secondary electro-desalination devices are electrodialysis equipment, which consists of main components such as a water distribution plate, an ion exchange membrane, electrodes, and a clamping device. For example, the water distribution plate, anion exchange membrane, and cation exchange membrane are alternately arranged between the positive electrode and the negative electrode to form a multi-layer compartment. Under the action of the external electric field between the positive and negative electrodes, the anions and cations in the aqueous solution entering the compartment will migrate toward the anode and cathode, respectively. Because the cation membrane only allows cations to pass and blocks anions, and the anion membrane only allows anions to pass and blocks cations (i.e., if the fixed charge on the ion exchange membrane is opposite to the charge of the ion, the ion can pass, and if their charges are the same, the ion is repelled), the anions and cations in the dilute chamber migrate to the adjacent concentrated chamber, thereby desalinating the salt water.

[0034] The oxidation treatment device includes a two-dimensional electrocatalytic oxidation device, including an electrolysis device shell, an anode electrode plate, a cathode electrode plate, a liquid distribution pipe, and an aeration device; the main function of the oxidation treatment device is to remove COD (chemical oxygen demand) and ammonia nitrogen in the wastewater, using a two-dimensional electrocatalytic oxidation device. The working principle is: under a certain temperature and electric field, the organic matter in the solution is decomposed into ions and gas by electrocatalysis, with redox reaction as the core, and the organic matter is directly degraded through the anode reaction or the oxidants such as hydroxyl free radicals and ozone are generated through the anode reaction to degrade the organic matter, thereby reducing the organic pollutants in the solution.

[0035] In one embodiment, Figures 1 to 4 As shown, the secondary wastewater treatment unit also includes an ultrafiltration device, which is connected between the oxidation treatment device and the second medium-pressure reverse osmosis device. The liquid inlet of the ultrafiltration device is connected to the outlet of the oxidation treatment device. The ultrafiltration device includes a clean water outlet and a waste liquid outlet. The clean water outlet of the ultrafiltration device is connected to the second medium-pressure reverse osmosis device, and the waste liquid (concentrated water) outlet of the ultrafiltration device is connected to the liquid inlet of the oxidation treatment device. The ultrafiltration device has an ultrafiltration membrane, which can only allow solvents (such as water molecules), inorganic salts and small molecular organic matter in the wastewater to pass through the ultrafiltration membrane, while intercepting large molecular substances such as suspended matter, colloids, proteins and microorganisms in the solution, thereby achieving purification of the wastewater. Purifying the wastewater in advance through the ultrafiltration device can also ensure that the wastewater flowing through the second medium-pressure reverse osmosis device has a certain degree of purity, and can avoid a large number of impurities clogging the second medium-pressure reverse osmosis device, which will cause the purification effect of the second medium-pressure reverse osmosis device to decrease.

[0036] During use, the concentrated water produced in the primary wastewater treatment unit flows into the primary electro-deionization device, where the concentrated water is desalinated. The primary fresh water flowing out of the primary electro-deionization device through the fresh water outlet is input into the low-pressure reverse osmosis device, and the primary fresh water is filtered by the low-pressure reverse osmosis device. The filtered clean water is directly input into the produced water collection pool through the produced water outlet as produced water (low-pressure RO produced water). The wastewater (RO concentrated water) filtered by the low-pressure reverse osmosis device is input into the oxidation treatment device. In the oxidation treatment device, electrocatalytic oxidation equipment is used to remove organic matter and ammonia nitrogen in the wastewater. The wastewater is then transported to the ultrafiltration device for purification. In the ultrafiltration device, most of the large molecular organic matter and fine particulate matter remaining in the wastewater are intercepted and filtered. The filtered liquid is then transported to the second medium-pressure reverse osmosis device. The clean water filtered by the second medium-pressure reverse osmosis device is directly used as produced water (medium-pressure RO produced water) and passed into the produced water collection pool. The concentrated water obtained by the second medium-pressure reverse osmosis device is re-passed into the secondary electric desalination device, and the ultrafiltered concentrated water produced in the ultrafiltration device is then passed into the oxidation treatment device for treatment. The utility model can efficiently purify the comprehensive electroplating wastewater, and the treated low-pressure RO water and medium-pressure RO water can be reused in the production line to realize the recycling of wastewater; on the other hand, sulfate and chloride salts in the electroplating wastewater are recovered, overcoming the problem of high salt content in the discharged water after the existing electroplating wastewater treatment, realizing the resource disposal of wastewater, and having good environmental and economic benefits.

[0037] In one embodiment, Figures 1 to 4 As shown, through the primary wastewater treatment unit, a large amount of metal ions, ammonia nitrogen, phosphorus, organic matter, etc. in the wastewater can be removed, and the reverse osmosis water produced can be reused in the production line. The primary wastewater treatment unit includes a pretreatment device, a biochemical treatment device, a sterilization and disinfection device, and a first medium-pressure reverse osmosis device connected in sequence. The wastewater is subjected to medium-pressure reverse osmosis 1 in the first medium-pressure reverse osmosis device. The first medium-pressure reverse osmosis device includes a water production outlet and a waste liquid outlet. The water production outlet of the first medium-pressure reverse osmosis device is connected to the water production collection tank, and the waste liquid outlet of the first medium-pressure reverse osmosis device is connected to the liquid inlet of the primary electric desalination device. Preferably, biochemical treatment utilizes the action of microorganisms to convert organic pollutants in sewage into inorganic substances, while purifying the sewage. The action of the biochemical treatment device can remove nitrogen, phosphorus, and COD from the wastewater.

[0038] In this embodiment, if Figures 1 to 4As shown, the pretreatment device includes a first neutralization reaction tank, a first cyanide breaking tank, a first flocculation sedimentation tank, a sludge thickening tank, and a filter press connected in sequence. The filter press is connected to the sludge thickening tank, and the filtrate outlet of the filter press is connected to the liquid inlet of the biochemical treatment device. Preferably, the filter press is a plate and frame filter press. The plate and frame filter press is an intermittent solid-liquid separation device with the characteristics of being light, flexible, and reliable. The plate and frame filter press is composed of filter plates and filter frames arranged to form filter chambers. Under the action of a feed pump, the feed liquid is transported to each filter chamber, and the solid and liquid are separated by the filter medium. The plate and frame filter press is low-investment, energy-saving, and highly safe. When in use, the electroplating comprehensive wastewater is collected and flows into the pretreatment device of the primary wastewater treatment unit. In the pretreatment device, the metal ions, ammonia nitrogen, phosphorus, etc. in the wastewater react chemically and react again with the flocculant and coagulant aid to generate coarser flocs. After filtration by the plate and frame filter press, the filtrate is transported to the biochemical treatment device. In the biochemical treatment device, the organic matter in the wastewater is decomposed into water and carbon dioxide by microorganisms and removed, and the ammonia nitrogen is converted into nitrogen and removed. It is then transported to the sterilization and disinfection device for disinfection. The treated effluent is transported to the first medium-pressure reverse osmosis device. The obtained fresh water (product water) can be used for the production line to achieve recycling. The wastewater (concentrated water) obtained by the first medium-pressure reverse osmosis unit flows into the primary electric desalination device of the electric desalination treatment unit. Preferably, the biochemical treatment device includes a regulating tank, an anaerobic tank, an anoxic tank, and an aerobic tank. Each tank body is connected in sequence, wherein the anaerobic tank and the anoxic tank are equipped with a stirrer, and the aerobic tank is equipped with an aeration pipe. The sludge generated by the biochemical treatment device is transported to the sludge thickening tank with a diaphragm pump. The outlet of the biochemical treatment device is connected to the inlet of the sterilization and disinfection device, and the outlet of the sterilization and disinfection device is connected to the inlet of the first medium-pressure reverse osmosis device. The sterilization and disinfection device includes a regulating tank and a disinfection tank. The sterilization and disinfection methods adopted include: ozone, ultraviolet radiation, and the addition of chemical agents, such as sodium hypochlorite and chlorine dioxide. The regulating tank can be used to adjust the wastewater to a suitable pH value according to the disinfection method adopted. The utility model treats the electroplating comprehensive wastewater through a primary wastewater treatment unit, an electric desalination treatment unit, and a secondary wastewater treatment unit, effectively removing pollutants such as heavy metal ions and organic matter in the electroplating wastewater, and producing pure water and industrial salt at the same time. It overcomes the problem of high salt content in the discharged water after the existing electroplating wastewater treatment, and realizes the resource-based disposal of the electroplating comprehensive wastewater.

[0039] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all perspectives, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims, not the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be encompassed within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0040] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A process system for recycling electroplating wastewater, characterized in that: It includes a primary wastewater treatment unit, an electric desalination treatment unit and a secondary wastewater treatment unit, the electric desalination treatment unit includes a primary electric desalination device, a secondary electric desalination device, a solid-liquid separation device and an evaporation device, the liquid inlet of the primary electric desalination device is connected to the waste liquid outlet of the primary wastewater treatment unit, the fresh water outlet of the primary electric desalination device is connected to the secondary wastewater treatment unit, and the concentrated water outlet of the primary electric desalination device is connected to the liquid inlet of the secondary electric desalination device; the fresh water outlet of the secondary electric desalination device is connected to the liquid inlet of the primary electric desalination treatment device, and the concentrated water outlet of the secondary electric desalination device is connected to the liquid inlet of the solid-liquid separation device; the liquid outlet of the solid-liquid separation device is connected to the liquid inlet of the evaporation device; the evaporation device includes a condensed water outlet and a by-product salt outlet, and the condensed water outlet is connected to the secondary wastewater treatment unit; the produced water outlet of the secondary wastewater treatment unit is connected to the produced water collection tank; the waste liquid outlet of the secondary wastewater treatment unit is connected to the liquid inlet of the secondary electric desalination device.

2. The process system for recycling electroplating comprehensive wastewater according to claim 1 is characterized in that: The electro-dionization treatment unit includes a concentrate pretreatment device, the liquid inlet of the concentrate pretreatment device is connected to the concentrate outlet of the secondary electro-dionization device, the liquid outlet of the concentrate pretreatment device is connected to the liquid inlet of the solid-liquid separation device, and the concentrate pretreatment device includes a second reaction tank, a second flocculation tank, a second coagulant aid tank, and a second sedimentation tank that are connected in sequence; the second reaction tank, the second flocculation tank, and the second coagulant aid tank are all equipped with mechanical agitators.

3. The electroplating comprehensive wastewater resource recovery process system according to claim 1 is characterized in that: The solid-liquid separation device is an immersed membrane filtration device, and the immersed membrane filtration device includes a curtain filter membrane for filtering wastewater.

4. The electroplating comprehensive wastewater resource recovery process system according to claim 3 is characterized in that: The membrane material of the curtain filter membrane is polyvinylidene fluoride, and the base layer of the curtain filter membrane is PET non-woven fabric.

5. The process system for recycling electroplating wastewater according to claim 1 is characterized in that: The secondary wastewater treatment unit includes a low-pressure reverse osmosis device, an oxidation treatment device and a second medium-pressure reverse osmosis device. The liquid inlet of the low-pressure reverse osmosis device is connected to the fresh water outlet of the first-level electric deionization device; the produced water outlet of the low-pressure reverse osmosis device is connected to the produced water collection tank, and the waste liquid outlet of the low-pressure reverse osmosis device is connected to the liquid inlet of the oxidation treatment device; the liquid inlet of the oxidation treatment device is also connected to the condensed water outlet of the evaporation device; the liquid outlet of the oxidation treatment device is connected to the liquid inlet of the second medium-pressure reverse osmosis device, the produced water outlet of the second medium-pressure reverse osmosis device is connected to the produced water collection tank, and the waste liquid outlet of the second medium-pressure reverse osmosis device is connected to the secondary electric deionization device.

6. The process system for recycling electroplating wastewater according to claim 5, characterized in that: The primary electro-desalination device and the secondary electro-desalination device both include electrodialysis equipment, and the oxidation treatment device includes a two-dimensional electrocatalytic oxidation device.

7. The process system for recycling electroplating wastewater according to claim 5, characterized in that: An ultrafiltration device is connected between the oxidation treatment device and the second medium-pressure reverse osmosis device. The liquid inlet of the ultrafiltration device is connected to the outlet of the oxidation treatment device, the purified water outlet of the ultrafiltration device is connected to the second medium-pressure reverse osmosis device, and the waste liquid outlet of the ultrafiltration device is connected to the liquid inlet of the oxidation treatment device.

8. The process system for recycling electroplating wastewater according to claim 1 is characterized in that: The primary wastewater treatment unit includes a pretreatment device, a biochemical treatment device, a sterilization and disinfection tank device and a first medium-pressure reverse osmosis device connected in sequence; the water production outlet on the first medium-pressure reverse osmosis device is connected to the water production collection tank; the waste liquid outlet of the first medium-pressure reverse osmosis device is connected to the liquid inlet of the primary electric desalination device.

9. The process system for recycling electroplating wastewater according to claim 8, characterized in that: The pretreatment device includes a first neutralization reaction tank, a first cyanide destruction tank, a first flocculation sedimentation tank, and a sludge concentration tank connected in sequence. The sludge concentration tank is connected to a filter press, and the filtrate outlet of the filter press is connected to the liquid inlet of the biochemical treatment device.

10. The process system for recycling electroplating wastewater according to claim 9, characterized in that: The filter press is a plate and frame filter press.

Images