High-salinity wastewater treatment system

Abstract

The invention discloses a high-salinity wastewater treatment system, and relates to the technical field of wastewater treatment.The high-salinity wastewater treatment system comprises a three-stage clarification tank set, an activated carbon oil removal unit, a chelating resin adsorption module, an MVR evaporator and a three-evaporation four-effect evaporation.According to the high-salinity wastewater treatment system, residual metal elements such as nickel and cobalt in wastewater are adsorbed through resin; according to the system, valuable metals are recycled, resource waste is avoided, the quality of subsequent evaporated salt is remarkably improved, when the system is used for treating wastewater, metal elements in the wastewater can be effectively separated, so that high-quality sodium sulfate can be evaporated by MVR, the economic value of a product is improved, and meanwhile, in the subsequent three-evaporation four-effect evaporation process, the production cost is reduced. The produced sodium sulfate salt is subjected to optimization treatment of the system and is reasonably stored and treated, so that the double effects of resource recovery and product quality improvement are achieved, and the economic benefit and the resource utilization rate of the whole treatment process are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, in particular to a high-salt wastewater treatment system. Background Art

[0002] High-salt wastewater is widely produced in industrial fields such as chemical, pharmaceutical, electric power, and metallurgy. It is characterized by high salt content and complex composition (including heavy metals, organic matter and various inorganic salts). Direct discharge will seriously pollute water bodies and soil and damage the ecological environment. With the increasingly stringent environmental protection, efficient treatment of high-salt wastewater and resource recovery have become the core challenges of industrial pollution control. Although traditional treatment methods such as biological treatment, evaporation crystallization, and ion exchange have certain effects, they generally have high energy consumption, low by-product quality, and insufficient metal recovery rate. For example, high-salt wastewater in the chemical industry often contains precious metals such as nickel and cobalt. If they are not effectively recovered, it will not only cause waste of resources, but may also cause environmental risks.

[0003] Currently, the existing technologies for treating high-salinity wastewater have the following limitations:

[0004] Metal recovery and evaporation desalination are disconnected: While traditional resin adsorption methods can remove heavy metals, they are not deeply coupled with the evaporation system, resulting in wastewater that still contains high salt content after adsorption. Direct evaporation can easily lead to mother liquor enrichment problems, affecting the quality of salt crystals. While single evaporation technology has low energy consumption, it cannot selectively recover metals, resulting in low added value of by-products.

[0005] Low efficiency in mother liquor treatment: When treating high-concentration mother liquor, the existing evaporation crystallization method often requires frequent shutdowns for cleaning due to impurity accumulation. Furthermore, secondary evaporation equipment (such as multiple-effect evaporation) has poor adaptability to mother liquor, and is prone to scaling and material leakage, resulting in reduced salt recovery rates.

[0006] Zero emissions are difficult to achieve: Most technologies rely on terminal membrane separation or forced crystallization to achieve reuse, but the risk of membrane contamination is high, the crystallization product contains many impurities, and the quality of recycled water is unstable, making it difficult to meet emission standards.

[0007] In summary, existing technologies are difficult to achieve the goals of metal recovery, efficient evaporation and zero emission of high-salt wastewater, resulting in high treatment costs and low resource utilization. Therefore, there is an urgent need to develop a comprehensive treatment technology that integrates metal recovery, efficient evaporation and zero emission, break through the bottleneck of a single technology, reduce energy consumption while improving the quality of by-products, and ultimately achieve resource utilization and zero emission of wastewater throughout the entire process. Summary of the Invention

[0008] The purpose of the present invention is to make up for the shortcomings of the existing technology and provide a high-salt wastewater treatment system. The system can absorb residual metal elements such as nickel and cobalt in the wastewater through resin, which not only realizes the recovery of these valuable metals and avoids resource waste, but also significantly improves the quality of the subsequent distilled salt. At the same time, in the subsequent three-steam four-effect evaporation process, the sodium sulfate salt produced can be reasonably stored and processed. This dual effect of resource recovery and product quality improvement greatly improves the economic benefits and resource utilization of the entire treatment process.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: a high-salt wastewater treatment system, which comprises: a three-stage clarifier group, an activated carbon oil removal unit, a chelating resin adsorption module, an MVR evaporator, and a three-steam four-effect evaporator;

[0010] The three-stage clarifier group consists of clarifier No. 1, clarifier No. 2 and clarifier No. 3 arranged horizontally adjacent to each other. The adjacent clarifiers are connected by waist holes to separate the floating oil in the wastewater step by step and make the clarified water flow step by step.

[0011] The activated carbon oil removal unit is connected to the outlet of the clarifier and is used to further remove oil from the wastewater by activated carbon adsorption. The amount of activated carbon added is 0.03%-0.05% of the wastewater volume;

[0012] The chelate resin adsorption module comprises three resin adsorption tanks connected in series, the adsorption tanks are filled with resin and adopt a wastewater flow mode of top in and bottom out to adsorb nickel and cobalt metals in the wastewater;

[0013] The step-by-step evaporation system includes an MVR evaporator for primary evaporation and a triple-steam four-effect evaporator for secondary evaporation;

[0014] The mother liquor circulation treatment unit is used to adjust the MVR mother liquor to pH 6-8 and then pump it into the three-steam four-effect evaporator for circulation treatment, ultimately achieving zero wastewater discharge.

[0015] Furthermore, the waist hole operation steps of the three-stage clarifier group are as follows:

[0016] Wastewater is injected into the No. 1 clarifier until the liquid level reaches 50-100 mm above the top of the hole;

[0017] Open the hole between No. 1 and No. 2 clarifiers to allow the bottom water to flow into No. 2 pool;

[0018] Lead the clean water from No. 2 clarifier into No. 3 clarifier;

[0019] The clarification residence time of each stage is greater than 2 hours, and the total oil removal efficiency is greater than or equal to 90%.

[0020] Furthermore, the working process of the activated carbon oil removal unit is as follows:

[0021] Pump clarified wastewater into the degreasing tank to 90% of its capacity;

[0022] Add granular activated carbon at a ratio of 0.03%-0.05%;

[0023] Stir at 40-60 rpm for 45 ± 15 minutes;

[0024] The filter press performs solid-liquid separation at a pressure of 0.3-0.5 MPa.

[0025] Furthermore, the resin filled in the resin adsorption tank in the chelating resin adsorption module is a chelating resin that selectively adsorbs nickel and cobalt, and the resin tank is switched by valve to realize single-tank and double-tank parallel operation, which is used to selectively adsorb nickel and cobalt metals in wastewater, and recover metals and extend the resin life through the acid regeneration process.

[0026] Furthermore, the MVR evaporator in the step-by-step evaporation system is connected to the outlet of the resin adsorption tank group, which is used to perform preliminary evaporation and crystallization on the wastewater after resin adsorption and produce high-quality sodium sulfate salt, and discharge the mother liquor into the mother liquor pool.

[0027] Furthermore, the three-steam four-effect evaporator in the step-by-step evaporation module is connected to the mother liquor pool, which is used to perform secondary evaporation and concentration on the MVR mother liquor, including a pretreatment unit and an evaporation crystallization unit, to produce sub-quality sodium sulfate salt and achieve the discharge and reuse of recycled water that meets the standards.

[0028] Furthermore, the pretreatment unit of the three-steam four-effect evaporator includes: a pH adjustment module, a filter press;

[0029] The pH adjustment module is used to adjust the pH of the mother liquor to 6-8;

[0030] The filter press is used to remove impurities and crystallized salts in the mother liquor, and the filter residue is discarded.

[0031] Furthermore, the pH regulating module in the three-steam four-effect evaporator adjusts the pH by:

[0032] Monitor the mother liquor pH value in real time and start adding medicine when pH>8.5;

[0033] Inject 20% sulfuric acid solution through a metering pump at a rate of 0.5 L / min;

[0034] After reaching pH 7.0±0.5, stirring was maintained for 10 minutes.

[0035] Compared with the existing technology, this high-salt wastewater treatment system has the following beneficial effects:

[0036] 1. The high-salt wastewater treatment system of the present invention uses resin to adsorb residual nickel, cobalt and other metal elements in the wastewater, which not only realizes the recovery of these valuable metals and avoids resource waste, but also significantly improves the quality of the subsequent distilled salt. When treating wastewater, this system can effectively separate the metal elements in the wastewater, so that MVR can evaporate high-quality sodium sulfate salt, thereby improving the economic value of the product. At the same time, in the subsequent three-steam four-effect evaporation process, the sodium sulfate salt produced is optimized by the system and reasonably stored and processed. This dual effect of resource recovery and product quality improvement greatly improves the economic benefits and resource utilization of the entire treatment process.

[0037] 2. The present invention is a new method that comprehensively uses activated carbon, resin, MVR and three-distillation four-effect, which solves the disadvantages of the traditional distillation or resin adsorption method, such as the singleness, low utilization rate and high treatment cost. It can generate sodium sulfate as a by-product while treating wastewater, thus achieving zero discharge of production wastewater. The treated recycled water is directly discharged or enters the production system for reuse, eliminating the pollution of the environment by wastewater from the source. At the same time, the recycling of wastewater reduces the company's fresh water resource procurement cost and reduces production cost. The sodium sulfate produced by the system as a by-product can bring additional economic benefits to the company.

[0038] Other advantages, objects and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be learned from the practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] 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 or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0040] Figure 1 The present invention is an operation flow chart of a high-salt wastewater treatment system;

[0041] Figure 2 This is a schematic diagram of the system composition of a high-salt wastewater treatment system. DETAILED DESCRIPTION

[0042] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0043] like Figure 2 As shown, a high-salt wastewater treatment system comprises: a three-stage clarifier group, an activated carbon oil removal unit, a chelating resin adsorption module, an MVR evaporator, and a three-steam four-effect evaporator;

[0044] The three-stage clarifier group consists of clarifier No. 1, clarifier No. 2 and clarifier No. 3 arranged horizontally adjacent to each other. The adjacent clarifiers are connected by waist holes to separate the floating oil in the wastewater step by step and make the clarified water flow step by step.

[0045] The activated carbon oil removal unit is connected to the outlet of the clarifier and is used to further remove oil from the wastewater by activated carbon adsorption. The amount of activated carbon added is 0.03%-0.05% of the wastewater volume;

[0046] The chelate resin adsorption module comprises three resin adsorption tanks connected in series, the adsorption tanks are filled with resin and adopt a wastewater flow mode of top-in and bottom-out to adsorb nickel and cobalt metals in the wastewater. The resin filled in the resin adsorption tank is a chelate resin that selectively adsorbs nickel and cobalt, and the resin tanks are switched by valves to achieve single-tank and double-tank parallel operation for selectively adsorbing nickel and cobalt metals in the wastewater, and the metals are recovered and the resin life is extended through an acid regeneration process;

[0047] The step-by-step evaporation system includes an MVR evaporator for primary evaporation and a triple-effect evaporator for secondary evaporation. The MVR evaporator is connected to the outlet of the resin adsorption tank group and is used to perform preliminary evaporation and crystallization on the wastewater after resin adsorption and produce high-quality sodium sulfate salt, and discharge the mother liquor into the mother liquor pool. The triple-effect evaporator is connected to the mother liquor pool and is used to perform secondary evaporation and concentration on the MVR mother liquor. It includes a pretreatment unit and an evaporation and crystallization unit, produces sub-quality sodium sulfate salt and achieves discharge and reuse of recycled water that meets the standards. The pretreatment unit includes: a pH adjustment module and a pH adjustment module, wherein the pH adjustment module is used to adjust the pH of the mother liquor to 6-8, and the filter press is used to remove impurities and crystallized salts in the mother liquor, and the filter press residue is scrapped;

[0048] The mother liquor circulation treatment unit is used to adjust the MVR mother liquor to pH 6-8 and then pump it into the three-steam four-effect evaporator for circulation treatment, ultimately achieving zero wastewater discharge.

[0049] Example 1

[0050] This embodiment takes the treatment of high-salt wastewater produced by a chemical enterprise as an example. Figure 1 As shown, the specific implementation process of the high-salt wastewater treatment system of the present invention is described in detail. When treating wastewater, this system can effectively separate metal elements such as nickel and cobalt and a large amount of sodium sulfate contained in high-salt wastewater, so that MVR can evaporate high-quality sodium sulfate salt, thereby improving the economic value of the product.

[0051] In the initial stage of wastewater treatment, a three-stage clarifier group is used to carry out preliminary treatment of the wastewater. The three-stage clarifier group consists of No. 1, No. 2 and No. 3 clarifiers. The volume of each clarifier is 180 cubic meters. They are arranged horizontally adjacent to each other and connected through waist holes. First, the workshop wastewater is pumped into No. 1 clarifier. During the wastewater injection process, the liquid level changes are closely observed. When the liquid level reaches 80mm above the top of the hole, the hole between No. 1 and No. 2 clarifiers is opened. Since a small amount of oil mixed in the wastewater will float on the surface, the bottom layer is relatively clear at this time. The clean water flows into the No. 2 clarifier under the action of the liquid level difference. During this process, the inflow speed of the wastewater must be controlled to avoid disturbing the upper floating oil and ensure that the floating oil does not enter the No. 2 clarifier. When the liquid level in the No. 1 clarifier drops to close to the bottom of the hole, the hole is closed; then, the same operation method is used to introduce the clean water in the No. 2 clarifier into the No. 3 clarifier. The residence time for each stage of clarification is set at 2.5 hours. Through this step-by-step clarification method, the total oil removal efficiency can reach 92%, effectively removing the floating oil in the wastewater and reducing the burden on subsequent treatment.

[0052] After the third stage of clarification, the wastewater enters the activated carbon oil removal unit for further oil removal. The activated carbon oil removal unit is connected to the outlet of the clarifier and is used to further remove the oil in the wastewater through activated carbon adsorption. Granular activated carbon is added according to 0.04% of the wastewater volume, and the stirring device is turned on and stirred at a speed of 50 rpm for 45 minutes. During the stirring process, the activated carbon is in full contact with the wastewater and adsorbs the residual oil in the wastewater. After the stirring is completed, a filter press is used for solid-liquid separation. The pressure of the filter press is set to 0.4 MPa. After filtration, the filter residue is oily activated carbon, which is directly scrapped. The wastewater after oil removal is directly connected to the resin pre-liquid pool for standby. At this time, the oil content in the wastewater is significantly reduced, meeting the requirements of subsequent resin adsorption.

[0053] The degreasing wastewater enters the chelate resin adsorption module for the adsorption of metal elements such as nickel and cobalt. The module contains three resin adsorption tanks connected in series. Each resin adsorption tank is cylindrical. The tank is first filled with slag to support the resin and evenly distribute the wastewater. It is then filled with chelate resin that selectively adsorbs nickel and cobalt. The wastewater flows through the resin tank in an upward and downward flow mode. During operation, single-tank and double-tank parallel operation are achieved by valve switching. The flow rate is flexibly adjusted according to the wastewater flow rate and metal ion concentration. The nickel content in the inlet and outlet wastewater is tested. When the inlet concentration is 30ppm and the outlet nickel content is greater than 0.5ppm, the resin regeneration process is started. The resin regeneration uses 8% hydrochloric acid solution to circulate and flush the resin in the tank from bottom to top. During the flushing process, the flow rate of the hydrochloric acid solution is controlled so that the nickel, cobalt and other metals in the resin are fully dissolved into the acid solution to achieve metal recovery. After the flushing is completed, the resin is rinsed and soaked with tap water until the pH value of the resin soaking water reaches neutral, and the regeneration is completed, ensuring that the resin can continue to efficiently adsorb metal ions.

[0054] The main component of the wastewater after resin adsorption is sodium sulfate solution. At this time, the wastewater enters the MVR evaporator for evaporation and crystallization. There are two sets of MVR evaporators. During the evaporation process, water is continuously fed into the evaporator, and sodium sulfate crystals are continuously produced. The temperature, pressure and other parameters in the evaporator are precisely controlled to maintain stable evaporation conditions. As the evaporation proceeds, the mother liquor is gradually enriched. After 70 hours of continuous operation, the mother liquor in the evaporator is discharged into the mother liquor pool at one time. In this process, high-quality sodium sulfate can be produced with a large output. After inspection, it is directly transferred to the warehouse. At the same time, the recycled water generated is stored in the reuse or external drainage pool and can be used for some non-productive water use links within the enterprise to achieve initial recycling of water resources.

[0055] The mother liquor discharged from the MVR evaporator enters the three-steam four-effect evaporator for secondary evaporation and concentration. Before entering the three-steam four-effect evaporator, it is first processed in the pretreatment unit. First, the pH adjustment module is used to adjust the pH of the mother liquor. The pH value of the mother liquor is monitored in real time using the pH online monitoring device. When the pH is greater than 8.5, the dosing device is started and 20% sulfuric acid solution is slowly injected through the metering pump at a rate of 0.5L / min. During the adjustment process, the mother liquor is continuously stirred to fully mix the sulfuric acid solution with the mother liquor to ensure that the pH value drops evenly. When the pH value reaches 7.0±0.5, the dosing is stopped and stirring is maintained for 10 minutes to adjust the pH value. Stable, then the mother liquor enters the filter press to remove the enriched dust and a small amount of crystallized salt therein, and the filter residue produced by the filtration is scrapped. The pretreated mother liquor is pumped into the evaporation and crystallization unit of the three-steam four-effect evaporator for further evaporation, concentration and crystallization. During the evaporation process, according to the characteristics of the mother liquor and the evaporation situation, the temperature, pressure, steam flow and other parameters are optimized and adjusted to ensure the efficient and stable operation of the evaporation process. The sodium sulfate salt produced in this process is of poor quality and low output, and is stored in the warehouse for unified treatment. The recycled water produced can be discharged or reused in the production system, which further improves the utilization rate of water resources and achieves zero discharge of production wastewater.

[0056] To sum up, through the specific implementation process of this embodiment, it can be seen that the high-salt wastewater treatment system of the present invention can effectively treat high-salt wastewater containing metal elements such as nickel and cobalt, achieve the goals of metal recovery, high-quality salt product output and zero wastewater discharge, and has significant economic and environmental benefits.

[0057] Example 2

[0058] This embodiment is based on the background of an electronics manufacturing enterprise. During the production process, a large amount of high-salt wastewater is generated. This wastewater not only contains a high concentration of salt, but also contains heavy metal ions such as copper and zinc, as well as a small amount of organic matter. If discharged directly, it will cause serious pollution to the surrounding environment and also cause waste of water and metal resources. To solve this problem, the high-salt wastewater treatment system of the present invention is used to treat wastewater.

[0059] Composition and operation of processing system

[0060] (1) Three-stage clarifier group

[0061] The tertiary clarifier group consists of clarifiers No. 1, No. 2, and No. 3. The inner walls of the clarifiers are treated with anti-corrosion to prevent corrosion by wastewater. High-salt wastewater generated by the electronics manufacturing company is pumped into clarifier No. 1 through a pipe with a controlled inlet flow. The wastewater remains in clarifier No. 1 for four hours. Due to the density difference of the wastewater, large particles of suspended solids and oily substances gradually float up or settle. When the liquid level reaches 100mm above the waist hole, the hole between clarifiers No. 1 and No. 2 is opened, allowing the relatively clear wastewater at the bottom to slowly flow into clarifier No. 2. During this process, liquid level changes are monitored in real time using liquid level sensors to ensure a steady water flow and avoid disturbing the floating oil and sediment on the upper layer. Clarifier No. 2 also undergoes a four-hour sedimentation process, and the treated wastewater is then introduced into clarifier No. 3. After the three-stage clarification treatment, the suspended solids removal rate in the wastewater reaches 90%, and the oil removal rate reaches 85%, greatly reducing the burden of subsequent treatment.

[0062] (2) Activated carbon oil removal unit

[0063] The wastewater coming out of the clarifier enters the activated carbon oil removal unit, which is connected to the outlet of the clarifier and is used to further remove oil from the wastewater through activated carbon adsorption. It includes a stirring tank, a filter press and a filter residue scrapping module. Each time, clarified wastewater is pumped into the stirring tank, and then powdered activated carbon is added according to 0.05% of the wastewater volume. The stirring device is started, the stirring speed is set to 60 rpm, and the stirring time is 60 minutes. During the stirring process, the activated carbon fully adsorbs the remaining oil and some organic matter in the wastewater. In order to ensure the adsorption effect, the wastewater in the stirring tank is sampled and tested every 15 minutes to analyze the changes in the oil and organic matter content. After the stirring is completed, the wastewater is transported to the filter press through a pipeline for solid-liquid separation. After filtration, the filter residue obtained is activated carbon containing oil and organic matter, which is collected and harmlessly treated. The wastewater after oil removal enters the resin pre-liquid tank.

[0064] (3) Chelating resin adsorption module

[0065] The chelating resin adsorption module consists of three resin tanks connected in series. The adsorption tanks are filled with resin and adopt a wastewater flow method of top-in and bottom-out to adsorb nickel and cobalt metals in the wastewater. The deoiled wastewater enters from the top of the resin tank. When passing through the resin layer, heavy metal ions such as copper and zinc in the wastewater undergo chelation reactions with the active groups on the resin and are adsorbed on the resin. In order to ensure the uniformity of the adsorption effect, water distributors and water collectors are set at the top and bottom of the resin tank to enable the wastewater to pass through the resin layer evenly. The heavy metal ion content of the wastewater at the inlet and outlet of the resin tank is tested every 6 hours. When the copper ion content in the outlet wastewater is greater than 0.3ppm (the inlet concentration is 15-25ppm) or the zinc ion content is greater than 0.5ppm (the inlet concentration is 20-30ppm), it indicates that the adsorption capacity of the resin is close to saturation and needs to be regenerated. During the regeneration process, first close the wastewater inlet valve, and then inject a 7% sulfuric acid solution into the resin tank through the pipeline. The solution enters from the bottom of the resin tank and circulates and flushes the resin from bottom to top. During the flushing process, the sulfuric acid solution reacts with the heavy metal ions on the resin, displacing them and restoring the adsorption capacity of the resin. The flushing time is 3 hours, and then the resin is rinsed with clean water until the pH value of the outflowing water is close to neutral. The sulfuric acid solution containing heavy metal ions generated during the regeneration process is collected for subsequent metal recovery.

[0066] (4) Step evaporation system

[0067] The main components of the wastewater after resin adsorption are salts such as sodium sulfate and sodium chloride, which enter the MVR evaporator for preliminary evaporation and crystallization. The MVR evaporator uses a steam compressor to compress and heat the secondary steam for reuse, which is energy-saving and efficient. There are multiple heating tube bundles and evaporation chambers inside the evaporator. The wastewater is continuously fed into the evaporator at a stable flow rate, and the wastewater is evaporated and concentrated by steam heating. During the evaporation process, the temperature in the evaporator is controlled at 80-90°C and the pressure is -0.08MPa. As the water evaporates, the salt gradually crystallizes and precipitates. The crystallized salt is separated from the mother liquor by a centrifuge. The obtained salt product is dried and then quality tested. The test results show that the output salt product has a high purity, and the content of sodium sulfate reaches more than 95%. After the MVR evaporator has been running for 80 hours, the mother liquor enters the three-steam four-evaporation The three-effect evaporator performs secondary evaporation and concentration. Before entering the evaporator, the pH value of the mother liquor is first adjusted by the pH adjustment module, and the pH value of the mother liquor is monitored in real time using a pH meter. According to the test results, an appropriate amount of sodium hydroxide or hydrochloric acid solution is added to adjust the pH value to between 7 and 8. The adjusted mother liquor enters the filter press to remove impurities and a small amount of crystallized salt. The mother liquor after filter pressing enters the evaporation and crystallization unit of the three-effect evaporator. The three-effect evaporator uses steam for multiple uses to improve energy utilization. During the evaporation process, the temperature and pressure of each effect evaporator are reasonably adjusted according to the composition and concentration of the mother liquor. After evaporation and concentration, the salt in the mother liquor is further crystallized and precipitated, and the sub-quality salt product is obtained by separation through a centrifuge. The recycled water generated is directly discharged or reused in some non-productive water use links of the enterprise, realizing the recycling of water resources.

[0068] In summary, the high-salt wastewater treatment system of the present invention has significant effects and advantages in treating high-salt wastewater in electronic manufacturing enterprises, can bring good economic and environmental benefits to enterprises, achieve zero discharge of production wastewater, and reduce pollution to the surrounding environment.

[0069] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A high-salt wastewater treatment system, characterized in that: The system consists of three-stage clarifier group, activated carbon oil removal unit, chelating resin adsorption module, MVR evaporator, three-steam four-effect evaporator; The three-stage clarifier group consists of clarifier No. 1, clarifier No. 2 and clarifier No. 3 arranged horizontally adjacent to each other. The adjacent clarifiers are connected by waist holes to separate the floating oil in the wastewater step by step and make the clarified water flow step by step. The activated carbon oil removal unit is connected to the outlet of the clarifier and is used to further remove oil from the wastewater by activated carbon adsorption. The amount of activated carbon added is 0.03%-0.05% of the wastewater volume; The chelate resin adsorption module comprises three resin adsorption tanks connected in series, the adsorption tanks are filled with resin and adopt a wastewater flow mode of top in and bottom out to adsorb nickel and cobalt metals in the wastewater; The step-by-step evaporation system includes an MVR evaporator for primary evaporation and a triple-steam four-effect evaporator for secondary evaporation; The mother liquor circulation treatment unit is used to adjust the MVR mother liquor to a pH of 6-8 and then pump it into a three-steam four-effect evaporator for circulation treatment, ultimately achieving zero wastewater discharge.

2. A high-salt wastewater treatment system according to claim 1, characterized in that: The waist hole operation steps of the three-stage clarifier group are: Wastewater is injected into the No. 1 clarifier until the liquid level reaches 50-100 mm above the top of the hole; Open the hole between No. 1 and No. 2 clarifiers to allow the bottom water to flow into No. 2 pool; Lead the clean water from No. 2 clarifier into No. 3 clarifier; The clarification residence time of each stage is greater than 2 hours, and the total oil removal efficiency is greater than or equal to 90%.

3. A high-salt wastewater treatment system according to claim 1, characterized in that: The working process of the activated carbon deoiling unit is: Pump clarified wastewater into the degreasing tank to 90% of its capacity; Add granular activated carbon at a ratio of 0.03%-0.05%; Stir at 40-60 rpm for 45 ± 15 minutes; The filter press performs solid-liquid separation at a pressure of 0.3-0.5 MPa.

4. A high-salt wastewater treatment system according to claim 1, characterized in that: The resin adsorption tank in the chelate resin adsorption module is filled with a chelate resin that selectively adsorbs nickel and cobalt, and the resin tank is switched by a valve to achieve single-tank and double-tank parallel operation, which is used for selectively adsorbing nickel and cobalt metals in wastewater, and recovering metals and extending the resin life through an acid regeneration process.

5. A high-salt wastewater treatment system according to claim 1, characterized in that: The MVR evaporator in the step-by-step evaporation system is connected to the outlet of the resin adsorption tank group, and is used to perform preliminary evaporation and crystallization on the wastewater after resin adsorption and produce high-quality sodium sulfate salt, and discharge the mother liquor into the mother liquor pool.

6. A high-salt wastewater treatment system according to claim 1, characterized in that: The three-steam four-effect evaporator in the step-by-step evaporation module is connected to the mother liquor pool and is used to perform secondary evaporation and concentration on the MVR mother liquor, including a pretreatment unit and an evaporation crystallization unit, to produce sub-quality sodium sulfate salt and achieve qualified discharge and reuse of recycled water.

7. A high-salt wastewater treatment system according to claim 6, characterized in that: The pretreatment unit of the three-steam four-effect evaporator includes: a pH adjustment module and a filter press; The pH adjustment module is used to adjust the pH of the mother liquor to 6-8; The filter press is used to remove impurities and crystallized salts in the mother liquor, and the filter residue is discarded.

8. A high-salt wastewater treatment system according to claim 1, characterized in that: The pH regulating module in the three-steam four-effect evaporator adjusts the pH by: Monitor the mother liquor pH value in real time and start adding medicine when pH>8.5; Inject 20% sulfuric acid solution through a metering pump at a rate of 0.5 L / min; After reaching pH 7.0±0.5, stirring was maintained for 10 minutes.

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