High-concentration metal wastewater treatment method and system

Abstract

The invention provides a high-concentration metal wastewater treatment method and system.The method comprises the steps that the PH value of target wastewater is adjusted, so that the target wastewater is acidic, and first intermediate wastewater is formed; the first intermediate wastewater is subjected to micro-electrolysis treatment, second intermediate wastewater is formed, and the PH value of the second intermediate wastewater is higher than that of the first intermediate wastewater; performing oxygenolysis on the second intermediate wastewater to form third intermediate wastewater; the third intermediate wastewater is subjected to precipitation treatment, breakpoint chlorination and filtration treatment in sequence, and standard discharge water is obtained. According to the scheme, the wastewater treatment efficiency can be effectively improved, and the medication cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of wastewater treatment, and particularly relates to a high-concentration metal wastewater treatment method and system. BACKGROUND

[0002] In the wastewater treatment process of high-concentration metal wastewater, common methods include chemical precipitation, electrolysis, ion exchange, etc. However, the electrolysis method has high power consumption and large consumption of electrode metal when treating a large amount of wastewater, and the separated precipitates are not easy to handle and are prone to produce toxic gases. The ion exchange method uses organic skeleton ion exchange resin to effectively remove various harmful ions in wastewater, but the resin consumption is large, the regeneration liquid is difficult to handle, and a large amount of acid and alkali needs to be consumed, which greatly increases the treatment cost. In the chemical precipitation method, a large amount of ferric salt and polyaluminum chloride needs to be added, thereby increasing the salt content of water discharge, making it difficult to meet the standard for the discharge of residual metal ions in water, and chemical drugs need to be used to meet the standard, resulting in increased cost. SUMMARY

[0003] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a high-concentration metal wastewater treatment method and system to reduce the treatment cost of high-concentration metal wastewater.

[0004] To achieve the above-mentioned purposes and other related purposes, the present application provides a high-concentration metal wastewater treatment method, comprising: adjusting the pH value of the target wastewater to make the target wastewater acidic to form first intermediate wastewater; performing micro-electrolysis treatment on the first intermediate wastewater to form second intermediate wastewater, the pH value of the second intermediate wastewater being higher than that of the first intermediate wastewater; performing oxidative decomposition on the second intermediate wastewater to form third intermediate wastewater; performing precipitation treatment, breakpoint chlorination and filtration treatment on the third intermediate wastewater in sequence to obtain standard discharge water.

[0005] Optionally, the micro-electrolysis treatment on the first intermediate wastewater comprises: constructing electrodes and using the first intermediate wastewater as an electrolyte solution to form a plurality of fine cells; electrochemical reactions occur in the electrolyte solution.

[0006] Optionally, the precipitation treatment on the third intermediate wastewater comprises: performing first-time precipitation treatment on the third intermediate wastewater to obtain first subsidence and first supernatant; performing second-time precipitation treatment on the first supernatant to obtain second subsidence and second supernatant.

[0007] Optionally, the third intermediate wastewater is subjected to a first precipitation treatment, comprising: increasing the PH value of the third intermediate wastewater to above 10.0 to form a fourth intermediate wastewater; adding a first flocculating agent to the fourth intermediate wastewater to undergo hydrolysis and generate heterocharged colloids to contact with colloids and suspended solids in water to form flocculating bodies; adding a second flocculating agent to flocculate the flocculating bodies into flocculating clusters; stirring the wastewater solution containing the flocculating clusters; standing to precipitate the flocculating clusters to form the first subsidence.

[0008] Optionally, the breakpoint chlorination comprises: controlling the second supernatant to enter the chlorination tank and controlling the PH value to be between 7 and 8; adding sodium hypochlorite and ammonia nitrogen, and controlling the mass ratio of sodium hypochlorite to ammonia nitrogen to be 1:7; introducing sodium chlorate to perform a breakpoint chlorination chemical oxidation reaction, and reducing the unreacted chlorine.

[0009] Optionally, after the third intermediate wastewater is subjected to a filtration treatment, the method further comprises: subjecting the filtered remaining slurry, the first subsidence and the second subsidence to pressure filtration dewatering for solid-liquid separation.

[0010] Optionally, the PH value of the target wastewater is adjusted, comprising: adjusting the PH value of the target wastewater to 2.5-3.

[0011] To achieve the above object and other related objects, the present application provides a high-concentration metal wastewater treatment system applied to the high-concentration metal wastewater treatment method, which comprises: a wastewater tank for storing target wastewater; an adjusting tank connected to the wastewater tank through a pipeline for adjusting the PH value of the target wastewater to form a first intermediate wastewater; a micro-electrolysis tank connected to the adjusting tank through a pipeline for micro-electrolysis treatment of the first intermediate wastewater to form a second intermediate wastewater; a chemical oxidation tank connected to the micro-electrolysis tank through a pipeline for oxidative decomposition of the second intermediate wastewater to form a third intermediate wastewater; a precipitation tank connected to the chemical oxidation tank through a pipeline for precipitation treatment of the third intermediate wastewater; a chlorination tank connected to the precipitation tank through a pipeline for breakpoint chlorination treatment of the wastewater after the precipitation treatment.

[0012] Optionally, the system further comprises a filter for filtering the wastewater treated by the chlorination tank.

[0013] Optionally, the system further comprises a filter press for dewatering the precipitate and the suspended matter.

[0014] Optionally, the micro-electrolysis tank comprises a tank body and an anode and a cathode arranged in the tank body.

[0015] As described above, the high-concentration metal wastewater treatment method and system of the present application has the following beneficial effects: In the present scheme, by adjusting the pH of the target wastewater, the solubility of metal ions is increased, preparing for subsequent micro-electrolysis treatment, and providing micro-electrolysis efficiency. By micro-electrolysis treatment in the micro-electrolysis tank, not only the pH value of the wastewater is increased, but also the dosage of the subsequent precipitation treatment process is reduced, which plays a role in improving the efficiency of wastewater treatment and reducing the cost of medicine. At the same time, Fe(OH)3 with flocculation and adsorption function is generated in the micro-electrolysis effluent, which can further improve the treatment effect of the wastewater. In addition, the micro-electrolysis treatment makes the structure and characteristics of many organic matters in the high-concentration metal wastewater reach the purpose of degrading organic matter. After micro-electrolysis treatment, in the chemical oxidation tank, macromolecular organic matter undergoes advanced oxidation reaction to become small molecular organic matter or is directly mineralized into inorganic matter such as carbon dioxide and water, and at the same time, nitrate ions and sulfate ions are removed, so that the metal nickel ions form small flocculation groups for subsequent treatment. Then, the third intermediate wastewater after oxidation and decomposition is introduced into the precipitation tank for precipitation treatment, so that the metal ions such as nickel and iron are precipitated, so that the subsequent breakpoint chlorination and filtration treatment can be carried out, so that the effluent reaches the national standard, i.e. standard discharge water. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The flow chart of the high-concentration metal wastewater treatment method in the embodiment of the present application.

[0017] Figure 2 The structural block diagram of the high-concentration metal wastewater treatment system in the embodiment of the present application. DETAILED DESCRIPTION

[0018] The embodiments of the present application are described below by specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification.

[0019] The reference signs in the drawings of the specification include: wastewater tank 201, adjustment tank 202, micro-electrolysis tank 203, chemical oxidation tank 204, oxidation buffer tank 205, precipitation tank 206, chlorination tank 207, dechlorination tank 208, ultrafiltration tank 209, clean water tank 210, filter press 211.

[0020] First, some technical names in this application are explained as follows: Macromolecule generally refers to a compound with a large molecular weight, usually composed of thousands of atoms, with a long polymer chain and a complex molecular structure.

[0021] For example, macromolecular organic matter refers to organic matter with complex structure, difficult to be biodegraded or chemically oxidized, and its molecular weight may be as high as several thousand or even tens of thousands of Daltons (Da).

[0022] Secondly, small molecules refer to compounds with small molecular weights, usually composed of fewer atoms, with relatively simple molecular structures. Small molecule compounds often have fast reaction rates in chemical reactions. In wastewater treatment, small molecule organic matter may refer to organic matter with relatively simple structure, easy to be biodegraded or chemically oxidized, and its molecular weight may be as low as tens to hundreds of Daltons (Da).

[0023] As shown in Figure 1 In an exemplary embodiment of the present application, a high-concentration metal wastewater treatment method is provided, comprising: Step S110, adjusting the pH value of the target wastewater to make the target wastewater acidic to form a first intermediate wastewater.

[0024] It should be noted that the target wastewater is metal wastewater, which can be nickel-iron wastewater, chromium-containing wastewater or copper-containing wastewater. Among them, the nickel-iron wastewater can be hydrogen production wastewater, electroplating wastewater or smelting wastewater, etc., which contains high-concentration nickel-iron. Nickel is a toxic heavy metal, which has potential harm to human health and ecological environment. High-concentration nickel-iron wastewater needs to be treated to meet the standard before being discharged. However, nickel is chemically active and easy to form strong cationic nickel (Ni²⁺) existing in wastewater, causing difficulty in wastewater treatment. At the same time, in addition to nickel ions, high-concentration nickel-iron wastewater also contains iron ions, other heavy metal ions, organic matter, acid and alkali substances, and the composition is relatively complex, which further increases the difficulty of wastewater treatment.

[0025] In this embodiment, the pH value is adjusted by adding an acid-base solution to make the target wastewater acidic, so as to improve the solubility of metal ions and prepare for the subsequent treatment steps.

[0026] Step S120, micro-electrolysis treatment is performed on the first intermediate wastewater to form a second intermediate wastewater, and the pH value of the second intermediate wastewater is higher than that of the first intermediate wastewater.

[0027] It is worth noting that micro-electrolysis treatment can change the structure and properties of many organic matters in high-concentration nickel-iron wastewater, achieving the purpose of degrading organic matter. And the micro-electrolysis effluent contains a large amount of Fe 2+The ferrous ions in the subsequent oxidation decomposition process are saved, and the Fe(OH)3 with flocculation and adsorption functions is generated, which can further improve the treatment effect of the wastewater. In addition, the pH value of the first intermediate wastewater after the micro-electrolysis is increased, which can effectively reduce the amount of alkali in the subsequent process and reduce the cost of the medicine.

[0028] In step S130, the second intermediate wastewater is subjected to oxidation decomposition, so that the macromolecular organic matters in the second intermediate wastewater are decomposed into small molecular organic matters or inorganic matters, to form third intermediate wastewater.

[0029] In the embodiment, the oxidation decomposition process causes the macromolecular organic matters in the second intermediate wastewater to undergo advanced oxidation reaction, to become small molecular organic matters or to be directly mineralized into inorganic matters such as carbon dioxide and water. At the same time, the nitrate ions and the sulfate ions are removed, and the metal nickel ions are formed into small flocculation groups, which are convenient for later treatment. Through the oxidation decomposition process, the refractory organic matters that cannot be removed by the traditional wastewater treatment technology can be effectively oxidized and removed.

[0030] In step S140, the third intermediate wastewater is subjected to precipitation treatment, breakpoint chlorination and filtration treatment in sequence, to obtain standard discharge water.

[0031] In the embodiment, after the high-concentration nickel-iron wastewater is subjected to the precipitation treatment, the heavy metal ions in the wastewater, especially the nickel ions and the iron ions, can be effectively removed. The breakpoint chlorination is further used to remove the pollution factors such as ammonia nitrogen. The filtration treatment is mainly used for solid-liquid separation, so that the final discharge water meets the national standards.

[0032] It is worth noting that the standard of the standard discharge water can be the national standard, or a water discharge standard higher than the national standard which is self-established according to the requirements. In an exemplary embodiment, the first intermediate stage wastewater is subjected to micro-electrolysis treatment, which includes step S210 and step S220.

[0033] In step S210, electrodes are constructed, and the first intermediate wastewater is used as an electrolyte solution to form a plurality of fine cells.

[0034] For example, in an acidic condition, the wastewater is used as an electrolyte solution, iron is used as an anode, and carbon-containing substances are used as a cathode, to form numerous fine primary cells.

[0035] In step S210, an electrochemical reaction occurs in the electrolyte solution.

[0036] It is worth mentioning that the micro-electrolysis method is a good process for wastewater treatment by forming a primary cell using the principle of metal corrosion. It is to generate high and low potential difference by using micro-electrolysis materials filled in the wastewater to electrolyze the wastewater without electricity, so as to achieve the purpose of degrading organic pollutants. In the slightly acidic wastewater, the newly generated hydrogen in the electrode reaction can have an oxidation-reduction reaction with the organic and inorganic components in the wastewater, which can destroy the color-forming groups in the wastewater and even break the polymer chain, so as to achieve the purpose of decolorization. Iron is a active metal, which can reduce some nitro compounds to biodegradable amine compounds under acidic conditions. The iron ions and ferrous ions generated by electrolysis are hydrolyzed and polymerized to form iron hydroxide and ferrous hydroxide polymer, which exists in the form of colloid and has the functions of precipitation, flocculation and adsorption. The pollutants are flocculated and precipitated together, so as to remove the organic matter in the wastewater.

[0037] In an exemplary embodiment, the process of performing the precipitation treatment on the third intermediate wastewater includes at least step S210 and step S220.

[0038] Step S210, performing the first precipitation treatment on the third intermediate wastewater to obtain first subsidence and first supernatant.

[0039] In this embodiment, a chemical precipitant is added to the third intermediate wastewater for the precipitation treatment.

[0040] For example, the chemical precipitant can be polyaluminum chloride (PAC) to improve the heavy metal removal efficiency. In addition to the precipitation effect, the polyaluminum chloride also has a certain coagulation and decolorization effect, which helps to improve the visual sense of the wastewater with color and reduce the burden of the subsequent treatment process.

[0041] Step S220, performing the second precipitation treatment on the first supernatant to obtain second subsidence and second supernatant.

[0042] In this embodiment, since the content of nickel ions in the first supernatant after single precipitation is still high, a coagulant and a flocculant need to be added for secondary precipitation.

[0043] In an exemplary embodiment, the process of performing the first precipitation treatment on the third intermediate wastewater includes step S310 to step S340.

[0044] Step S310, increasing the PH value of the third intermediate wastewater to 10.0 or more to form a fourth intermediate wastewater.

[0045] For example, lime milk and sodium hydroxide are added to the third intermediate wastewater to increase the pH of the wastewater to 10.0 or more.

[0046] Step S320, adding a first flocculant to the fourth intermediate wastewater to cause hydrolysis and generate heterocharged colloids to contact with colloids and suspended solids in the water to form flocculation bodies.

[0047] For example, after adding the polyaluminum chloride (i.e., the first flocculant), hydrolysis occurs and generates heterocharged colloids to contact with colloids and suspended solids in the water to form fine flocculation bodies (commonly known as algae).

[0048] Step S330, adding a second flocculant to cause the flocculation bodies to flocculate into flocculation groups.

[0049] For example, adding polyacrylamide (i.e., the second flocculant) to form flocculation groups so that most heavy metal ions generate insoluble hydroxide precipitates in an alkaline environment.

[0050] Step S340, stirring the wastewater solution containing the flocculation groups.

[0051] It is worth noting that the appropriate stirring intensity enables the small flocculation bodies to collide with each other to form large flocculation bodies and prevents the large flocculation bodies from precipitating.

[0052] Step S350, allowing the flocculation groups to precipitate to form the first subsidence.

[0053] In this embodiment, the flocculation process is followed by sludge-water separation to form the first subsidence and the first supernatant.

[0054] In an exemplary embodiment, the breakpoint chlorination includes steps S410 to S430.

[0055] Step S410, controlling the second supernatant to enter a chlorination tank and controlling the pH value to be between 7 and 8.

[0056] It is worth noting that when the pH of the water entering the tank is controlled to be between 7 and 8, the removal rate of NH3-N (i.e., the ammonia nitrogen content index in the water) is better.

[0057] Step S420, adding sodium hypochlorite and ammonia nitrogen and controlling the mass ratio of the added sodium hypochlorite to the ammonia nitrogen to be 1:7.

[0058] It is worth noting that when the mass ratio of the added sodium hypochlorite to the ammonia nitrogen is controlled to be 1:7 during operation, the mass concentration of NH3-N in the water is basically below 10 mg / L.

[0059] Step S430, passing sodium chlorate to perform a breakpoint chlorination chemical oxidation reaction and reducing the unreacted chlorine.

[0060] It is worth mentioning that when the sodium hypochlorite is added into the wastewater containing ammonia nitrogen, when the amount reaches a certain value, the amount of chlorine ions contained in the wastewater is the least, and the concentration of ammonia is zero; continue to add sodium hypochlorite, and the free chlorine in the solution will increase. The value point is called the breakpoint, and the concentration of free chlorine ions is also the lowest in the wastewater. At this time, the chlorine is reduced, and the ammonia nitrogen is basically oxidized. Continue to add chlorine to produce free residual chlorine.

[0061] For example, the second supernatant wastewater enters the chlorination tank to further remove the pollution factors such as ammonia nitrogen by the method of breakpoint chlorination chemical oxidation, and then the unreacted chlorine is reduced in the dechlorination tank to reduce the secondary pollution caused by residual chlorine in water.

[0062] For example, when the unreacted chlorine is reduced, the dechlorination can be carried out by adding a reducing agent Na2S2O3 to ensure that the total residual chlorine index after dechlorination meets the discharge standard.

[0063] In an example embodiment, after the third intermediate wastewater is filtered, the method further comprises: pressure filtration dewatering the filtered remaining pulp, the first subsidence and the second subsidence to separate the solid and liquid.

[0064] In this embodiment, in order to increase the wastewater treatment effect, the filtered remaining pulp, the first subsidence and the second subsidence are pressure filtration dewatered to separate the solid and liquid. The pressure filtration dewatering will be returned to the wastewater tank for wastewater treatment.

[0065] In an example embodiment, the PH value of the target wastewater is adjusted, including: adjusting the PH value of the target wastewater to 2.5-3.

[0066] In this embodiment, in order to improve the treatment effect of the subsequent treatment process, the PH value of the target wastewater is adjusted to 2.5-3.

[0067] It should be noted that the pH is adjusted before microelectrolysis, which has the following but not limited effects: (1) to facilitate demulsification and separation; (2) to adjust the water quality so that the water quality is balanced, which is beneficial to the next process; (3) to keep the water inflow constant, to provide stable and quantifiable water supply for the subsequent process.

[0068] In an example embodiment of the present application, a high-concentration metal wastewater treatment system is provided for the high-concentration metal wastewater treatment method described above, and the system comprises: The wastewater tank 201 is used to store the target wastewater; The adjustment tank 202 is connected to the wastewater tank 201 through a pipeline to adjust the PH value of the target wastewater to form the first intermediate wastewater; The microelectrolysis tank 203 is connected to the adjustment tank 202 through a pipeline to microelectrolyze the first intermediate wastewater to form the second intermediate wastewater; The chemical oxidation tank 204 is connected with the micro-electrolysis tank 203 through a pipeline for water communication, and is used for oxidizing and decomposing the second intermediate wastewater to form third intermediate wastewater; The sedimentation tank 206 is connected with the chemical oxidation tank 204 through a pipeline for water communication, and is used for sedimentation treatment of the third intermediate wastewater; The chlorination tank 207 is connected with the sedimentation tank 206 through a pipeline for water communication, and is used for breakpoint chlorination treatment of the wastewater after the sedimentation treatment.

[0069] As shown in the examples, Figure 2 As shown in the examples, the wastewater tank 201, the conditioning tank 202, the micro-electrolysis tank 203, the chemical oxidation tank 204, the oxidation buffer tank 205, the sedimentation tank 206, the chlorination tank 207, the dechlorination tank 208, the ultrafiltration tank 209 and the clean water tank 210 are connected in sequence along the water flow direction, wherein the oxidation buffer tank 205 can store wastewater from different time periods or different sources, and through mixing and equalization, the water quality entering the subsequent treatment units is more stable, the formation of dead water zones is reduced, and the progress of the oxidation reaction is promoted. The dechlorination tank 208 is used for reducing the chlorine that has not been completely reacted, so as to reduce the secondary pollution caused by residual chlorine in the water, the ultrafiltration tank 209 is used for filtration treatment of the wastewater, and the clean water tank is used for storing the clean water output by the ultrafiltration tank.

[0070] As shown in the examples, the wastewater tank 201, the conditioning tank 202, the micro-electrolysis tank 203, the chemical oxidation tank 204, the oxidation buffer tank 205, the sedimentation tank 206, the chlorination tank 207, the dechlorination tank 208, the ultrafiltration tank 209 and the clean water tank 210 are connected through a pipeline for water communication, and the wastewater is pumped through the pipeline by setting a pump on the pipeline.

[0071] As shown in the examples, the sedimentation tank includes a first sedimentation tank and a second sedimentation tank, and the first sedimentation tank and the second sedimentation tank are connected through a pipeline. The first sedimentation tank is used for first sedimentation treatment, and the second sedimentation tank is used for second sedimentation treatment.

[0072] In the embodiment, the wastewater pool 201 is arranged to accommodate industrial wastewater. The pH of the target wastewater is adjusted in the adjusting pool to increase the solubility of metal ions, so as to prepare for the subsequent micro-electrolysis treatment and improve the micro-electrolysis efficiency. The micro-electrolysis treatment is performed in the micro-electrolysis pool 203, so as to not only increase the pH of the wastewater, but also reduce the amount of chemicals used in the subsequent precipitation treatment and the like. Meanwhile, the Fe(OH)3 with flocculation and adsorption functions is generated in the micro-electrolysis effluent, so as to further improve the treatment effect of the wastewater. In addition, the micro-electrolysis treatment changes the structure and characteristics of many organic matters in the high-concentration nickel-iron wastewater, so as to achieve the purpose of degrading the organic matters. After the micro-electrolysis treatment, the macromolecular organic matters are subjected to the advanced oxidation reaction in the chemical oxidation pool 204, so as to become small-molecular organic matters or be directly mineralized into inorganic matters such as carbon dioxide and water. Meanwhile, the nitrate ions and the sulfate ions are also removed, so that the nickel ions form small flocculation groups, which are convenient for the subsequent treatment. Then, the third intermediate wastewater after the oxidation and decomposition is introduced into the precipitation pool 206 to perform the precipitation treatment, so as to precipitate the nickel-iron and other metal ions. The subsequent breakpoint chlorination and filtration treatment are performed, so that the effluent reaches the national standard, that is, the standard discharge water is obtained.

[0073] In an exemplary embodiment, the system further comprises a filter for filtering the wastewater after the chlorination pool treatment.

[0074] Exemplarily, the filter is a ceramic flat membrane arranged in the ultrafiltration pool 209, so as to reduce the colority and the suspended matters of the supernatant, so as to achieve the discharge standard.

[0075] In an exemplary embodiment, the system further comprises a filter press 211 for pressure filtration and dewatering of the precipitate and the suspended matters.

[0076] In the embodiment, the filter press 211 is used to perform pressure filtration and dewatering of the precipitate and the suspended matters, so as to form a mud cake and water discharged by the filter press. The water discharged by the filter press is re-introduced into the wastewater pool for treatment.

[0077] Exemplarily, the filter press 211 is used to compress the sludge in the precipitation pool 206, the ultrafiltration pool 209 and the clean water pool 210.

[0078] In an exemplary embodiment, the micro-electrolysis pool comprises a pool body and an anode and a cathode arranged in the pool body.

[0079] In the embodiment, the wastewater is used as an electrolyte solution, iron is used as the anode, and carbon-containing substances are used as the cathode, so as to form numerous fine primary cells, and electrochemical reactions occur in the aqueous solution.

[0080] In an exemplary embodiment, the material of the wastewater pool 201 is a corrosion-resistant material such as PP, PVC and stainless steel 316L. The wastewater pool 201 can be provided with a liquid level sensor for controlling the water inflow / outflow and a stirring device for preventing precipitation.

[0081] In an exemplary embodiment, the adjusting tank 202 can be provided with a pH adjusting device, a pH on-line monitor, and a stirring device. The pH adjusting device is used to adjust the pH value of the wastewater to the required range for the micro-electrolysis process. The pH on-line monitor can feedback control the amount of chemicals added. The stirring device can be mechanical stirring or aeration stirring to ensure uniform pH.

[0082] In an exemplary embodiment, the micro-electrolysis tank 203 can be provided with a water distribution system, such as a perforated pipe or a water distributor, to ensure uniform water flow, and an aeration device, such as a bottom aeration pipe.

[0083] In an exemplary embodiment, the system further comprises an automatic control device (such as a PLC system integration), an abnormal alarm device (such as pH value exceeding the standard, abnormal liquid level), and an emergency tank. The emergency tank is used to treat sudden high-concentration wastewater.

[0084] The high-concentration metal wastewater treatment method and system of the present application have the advantages of simple operation, stable operation, low cost, high treatment efficiency, etc., and can also save water and chemical usage, reduce environmental pollution, and promote sustainable development. The method and system can be applied to high-concentration metal wastewater treatment in electroplating, metallurgy, chemical industry, etc., such as high-concentration metal wastewater treatment in an electrochemical tank, and the process parameters can be adjusted according to the actual water quality.

[0085] The above embodiments are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

Claims

1. A method for treating high-concentration metal wastewater, characterized in that, include: The pH value of the target wastewater is adjusted to make it acidic, thus forming the first intermediate wastewater; The first intermediate wastewater is subjected to micro-electrolysis treatment to form a second intermediate wastewater, the pH value of which is higher than that of the first intermediate wastewater. The second intermediate wastewater is oxidized and decomposed to form the third intermediate wastewater; The third intermediate wastewater is subjected to sedimentation, breakpoint chlorination, and filtration treatment in sequence to obtain standard discharge water.

2. The method for treating high-concentration metal wastewater according to claim 1, characterized in that, The wastewater from the first intermediate stage is subjected to micro-electrolysis treatment, including: Electrodes were constructed, and multiple microcells were formed using the first intermediate wastewater as the electrolyte solution. An electrochemical reaction occurs in an electrolyte solution.

3. The method for treating high-concentration metal wastewater according to claim 1, characterized in that, The third intermediate wastewater is subjected to sedimentation treatment, including: The third intermediate wastewater is subjected to a first sedimentation treatment to obtain a first sediment and a first supernatant. The first supernatant was subjected to a second precipitation treatment to obtain the second sediment and the second supernatant.

4. The method for treating high-concentration metal wastewater according to claim 1, characterized in that, The third intermediate wastewater undergoes a first sedimentation treatment, including: Increase the pH value of the third intermediate wastewater to above 10.0 to form the fourth intermediate wastewater; The first flocculant is added to the fourth intermediate wastewater to cause hydrolysis and generate oppositely charged colloids that come into contact with colloids and suspended solids in the water to form flocs; A second flocculant is added to cause the flocs to flocculate into flocs; Stir the wastewater solution containing flocculent flocculation; Allowing the mixture to stand allows the flocs to settle and form the first sediment.

5. The method for treating high-concentration metal wastewater according to claim 3, characterized in that, Breakpoint chlorination includes: Control the flow of the second supernatant into the chlorination tank and maintain the pH value between 7 and 8; Add sodium hypochlorite and ammonia nitrogen, and control the mass ratio of sodium hypochlorite to ammonia nitrogen to be 1:7; Sodium chlorate is introduced to carry out a breakpoint chemical oxidation reaction with chlorination, and the unreacted chlorine is reduced.

6. The method for treating high-concentration metal wastewater according to claim 3, characterized in that, After filtering the third intermediate wastewater, the method further includes: The remaining slurry after filtration, the first sediment, and the second sediment are dehydrated by pressure filtration to separate solids and liquids.

7. The method for treating high-concentration metal wastewater according to any one of claims 1 to 7, characterized in that, pH adjustment of the target wastewater includes: The pH value of the target wastewater is adjusted to 2.5~3.

8. A high-concentration metal wastewater treatment system, characterized in that, The system, applied to the high-concentration metal wastewater treatment method as described in any one of claims 1 to 7, comprises: Wastewater pond, used to store the target wastewater; The equalization tank is connected to the wastewater tank via a pipeline and is used to adjust the pH value of the target wastewater to form the first intermediate wastewater. A micro-electrolysis cell, connected to the equalization tank via a pipeline, is used to micro-electrolyze the first intermediate wastewater to form a second intermediate wastewater. A chemical oxidation tank, connected to the micro-electrolysis tank via a pipeline, is used to oxidize and decompose the second intermediate wastewater to form a third intermediate wastewater. A sedimentation tank, connected to the chemical oxidation tank via a pipeline, is used to treat the third intermediate wastewater through sedimentation. The chlorination tank, connected to the sedimentation tank via a pipeline, is used to perform breakpoint chlorination treatment on the wastewater after sedimentation.

9. The high-concentration metal wastewater treatment system according to claim 8, characterized in that, The system also includes a filter element for filtering the wastewater treated by the chlorination tank.

10. The high-concentration metal wastewater treatment system according to claim 8, characterized in that, The system also includes a filter press for dewatering precipitates and suspended solids; the microelectrolysis cell includes a cell body and an anode and a cathode disposed within the cell body.

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