Rain sewage and wastewater cooperative treatment method and system in non-ferrous metal resource recycling industry

Abstract

The invention discloses a method and a system for co-processing rain sewage wastewater in the non-ferrous metal resource recycling industry, the rain sewage wastewater comprises rainwater, general production wastewater, acidic wastewater and acidic wastewater, and the method comprises the following steps: carrying out coagulating sedimentation, filtration and low-pressure reverse osmosis desalination treatment on the rainwater and the general production wastewater; concentrated water of reverse osmosis is used as a liquid preparation of lime milk of waste acid wastewater and acidic wastewater; the method comprises the following steps: carrying out vulcanization reaction on waste acid wastewater and acid wastewater, carrying out neutralization treatment with lime milk, softening, filtering, resin softening, reverse osmosis and evaporative crystallization treatment, taking evaporated steam condensate as reuse water, and carrying out resource utilization on salt obtained by evaporative crystallization. According to the invention, zero discharge of wastewater generated in the non-ferrous metal recovery process can be realized, no wastewater is discharged to the outside, and natural water and soil are ensured not to be polluted.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly relates to a method and system for co-treatment of rainwater and sewage wastewater in the non-ferrous metal resource recovery industry. Background Art

[0002] In recent years, in response to the country's green development concept, the non-ferrous metal resource recovery industry has developed rapidly. During the process of non-ferrous metal resource recovery, a large amount of wastewater containing heavy pollutants such as heavy metals, arsenic, and soluble salts is generated, which has become a threshold restricting the process of turning non-ferrous metals from waste to treasure. Seeking production wastewater treatment technologies with better treatment effects, stronger process stability, and lower operating costs, reducing wastewater discharge, and achieving zero wastewater discharge have become the internal needs and external requirements for the development of the non-ferrous metal resource recovery industry.

[0003] In the wastewater treatment system of the non-ferrous metal smelting industry, the sources of wastewater are usually divided into initial rainwater and production wastewater; production wastewater mainly includes waste acid wastewater, acidic wastewater, and general production wastewater, etc. Waste acid wastewater mainly comes from the purification process in the sulfuric acid production from metal smelting flue gas. The wastewater is strongly acidic and has a high heavy metal content; the main sources of acidic wastewater are the post-treatment liquid of waste acid, laboratory wastewater, acid mist purification drainage, etc. The wastewater is slightly acidic and has a high heavy metal content; general wastewater refers to other wastewater discharged during the production process except waste acid wastewater and acidic wastewater, mainly including concentrated brine from desalination plants and softening water plants, indirect cooling drainage, flushing water for roads and ordinary ground, etc. The wastewater has a pH close to neutral and contains a small amount of heavy metals.

[0004] Currently, the conventional engineering design for wastewater is to mix initial rainwater, general production wastewater with waste acid wastewater and acidic wastewater, and then discharge them up to standard after treatment. However, for resource recovery factories, the above treatment method has great drawbacks: The reason is that initial rainwater and general production wastewater have a low heavy metal content, low soluble salt content, and a pH close to neutral, and the water quality is relatively good; while process wastewater (mainly waste acid wastewater and acidic wastewater) has a high arsenic and heavy metal content, high soluble salt content, and extremely poor water quality; mixing them together for treatment will increase the operating cost of treating wastewater, and at the same time will also increase the risk of non-compliance of rainwater.

[0005] At the same time, with the increasing environmental protection pressure and the more stringent environmental protection policies, the wastewater treatment of non-ferrous metal resource recovery factories generally requires zero discharge. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the present invention provides a method and system for co-treatment of rainwater and sewage wastewater in the non-ferrous metal resource recovery industry.

[0007] The present invention also discloses a method for co - treating rainwater and sewage wastewater in the non - ferrous metal resource recovery industry. The rainwater and sewage wastewater include rainwater, general production wastewater, waste acid wastewater, and acidic wastewater. The co - treatment method includes: Collect rainwater and general production wastewater into a regulating tank, and fully mix and homogenize them; Perform coagulation and sedimentation treatment on the wastewater in the regulating tank; Perform first - stage multi - media filtration on the water produced after coagulation and sedimentation; Perform first - stage ultrafiltration on the water produced after the first - stage multi - media filtration; Perform low - pressure reverse osmosis desalination treatment on the water produced after the first - stage ultrafiltration. The desalted water is used as recycled water, and the high - salinity concentrated water is used as the lime - mixing water for waste acid wastewater and acidic wastewater; Collect waste acid wastewater and acidic wastewater into a waste acid tank, and fully mix and homogenize them; Perform sulfidation reaction treatment on the wastewater in the waste acid tank; Perform neutralization treatment on the water produced after the sulfidation reaction with lime milk; wherein, the lime milk is prepared by mixing lime with the mixing water; Perform softening treatment on the water produced after the neutralization reaction; Perform second - stage multi - media filtration on the water produced after the softening reaction; Perform second - stage ultrafiltration on the water produced after the second - stage multi - media filtration; Perform resin softening treatment on the water produced after the second - stage ultrafiltration; Perform medium - pressure reverse osmosis desalination treatment on the water produced after resin softening. The desalted water is used as recycled water; Perform high - pressure reverse osmosis concentration treatment on the high - salinity concentrated water after medium - pressure reverse osmosis. The water produced by high - pressure reverse osmosis is used as recycled water; Perform evaporation and crystallization treatment on the concentrated water after high - pressure reverse osmosis. The condensed steam during evaporation is used as recycled water, and the salt crystallized out during evaporation is used for resource utilization.

[0008] As a further improvement of the present invention, it further includes: performing softening treatment on the remaining high - salinity concentrated water after low - pressure reverse osmosis, the backwash wastewater of the second - stage multi - media filter, the backwash wastewater of the second - stage ultrafiltration device, the flushing wastewater and regeneration wastewater of the weak cation resin in the resin softening unit.

[0009] As a further improvement of the present invention, the turbidity of the water produced by the first - stage ultrafiltration is <0.2 NTU, and the SDI <5.

[0010] As a further improvement of the present invention, the sulfidation reaction treatment of the wastewater in the waste acid tank includes: Send the wastewater in the waste acid tank into the reaction tank, add a sulfiding agent to the reaction tank, and the sulfiding agent forms arsenic sulfide precipitation with the arsenic ions in the wastewater; the wastewater after the reaction enters the thickener, and the residence time of the wastewater in the thickener is not less than 12 h. The precipitation accumulates at the bottom of the thickener and is pumped to the dehydration system, and the arsenic-containing sludge filtered out by pressure filtration is treated as hazardous waste; the removal rate of arsenic ions and heavy metals in the effluent from the sulfidation reaction is not less than 98%.

[0011] As a further improvement of the present invention, the neutralization treatment of the water produced after the sulfidation reaction with lime milk includes: Adjust the pH of the wastewater by adding lime milk, and adjust the pH to 3 - 8; wherein, the lime is dissolved by rainwater and the highly saline concentrated water after low-pressure reverse osmosis of general production wastewater to obtain lime milk; during this process, fluoride ions react with calcium to produce precipitation to remove fluoride ions in the raw water, so that the fluoride ions in the effluent do not exceed 20 mg / L; at the same time, sulfate ions also precipitate in the form of gypsum with calcium ions, and the gypsum is treated as general solid waste, and the clear liquid is subjected to subsequent softening treatment.

[0012] As a further improvement of the present invention, it also includes: directly collecting part of the acidic wastewater into the sewage adjustment tank, fully mixing and homogenizing it, and then performing softening treatment.

[0013] The present invention also discloses a method for co-treatment of rain and sewage wastewater in the non-ferrous metal resource recovery industry, which is used to implement the method for co-treatment of rain and sewage wastewater in the non-ferrous metal resource recovery industry. The rain and sewage wastewater includes rainwater, general production wastewater, waste acid wastewater and acidic wastewater. The co-treatment system includes: A regulating tank, a coagulation and precipitation unit, a first multi-media filter, a first ultrafiltration device and a low-pressure reverse osmosis unit are arranged in sequence along the treatment direction of rainwater and general production wastewater. The water produced by the low-pressure reverse osmosis is used as recycled water, and the concentrated water from the low-pressure reverse osmosis is used as the lime preparation water for waste acid wastewater and acidic wastewater; A waste acid tank, a sulfidation reaction unit, a neutralization reaction unit, a softening unit, a second multi-media filter, a second ultrafiltration device, a resin softening unit, a medium-pressure reverse osmosis unit, a high-pressure reverse osmosis unit and an evaporation and crystallization unit are arranged in sequence along the treatment direction of waste acid wastewater and acidic wastewater; the condensed steam from evaporation is used as recycled water, and the salt crystallized by evaporation is recycled; wherein, lime milk is added in the neutralization reaction unit, and the lime milk is prepared by lime and the preparation water.

[0014] The present invention discloses Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention is used for the comprehensive treatment of wastewater in non-ferrous metal resource recovery factories, which can achieve zero discharge of wastewater generated during the non-ferrous metal recovery process, without discharging any wastewater to the outside, and ensuring that natural water bodies and soil are not polluted.

[0015] 2. The present invention realizes the comprehensive treatment of wastewater in non-ferrous metal resource recovery factories, reducing the treatment cost: rainwater, general production wastewater, waste acid wastewater, and acidic wastewater are treated separately, saving operating costs; at the same time, the concentrated water after membrane concentration of rainwater and general wastewater is used as the dosing water for the treatment process of waste acid wastewater and acidic wastewater, without introducing fresh water from the outside, thereby reducing the wastewater volume of the whole plant, reducing the treatment cost of wastewater, and realizing the comprehensive utilization of the whole plant's wastewater.

[0016] 3. The present invention removes arsenic and heavy metals through two stages to ensure that the produced water quality meets the standards, while significantly reducing the output of hazardous waste, thereby reducing the treatment cost: the sulfide method + lime ferric salt method is used for two-stage arsenic and heavy metal removal: in the first step, the sulfide method is used to remove arsenic ions and heavy metals to a low content, and in the second step, the lime ferric salt method is used to neutralize waste acid wastewater and acidic wastewater, generating a large amount of calcium sulfate precipitation, while removing the remaining arsenic and heavy metals in the wastewater. The present invention reduces the output of hazardous waste, and only a small amount of sludge produced during the sulfide process is treated as hazardous waste, and the calcium sulfate produced by the lime ferric salt method can be recycled to production.

[0017] 4. The present invention uses a multi-stage concentration + MVR process for desalination, reducing the evaporation water volume, and at the same time uses negative pressure low-temperature evaporation with low operating costs: a medium-pressure reverse osmosis + high-pressure reverse osmosis process is used to concentrate the wastewater first, reducing the water volume entering the evaporation crystallization, thereby reducing the treatment scale of evaporation crystallization, and the produced water of reverse osmosis can be directly recycled to the factory area; the evaporation crystallization system uses a low-temperature negative pressure evaporation method, thereby reducing steam and power consumption.

[0018] 5. The present invention effectively solves the fouling problem of the reverse osmosis membrane during the high-fold concentration process: a soft reaction + resin softening two-stage softening process is used to remove the calcium and magnesium hardness in the wastewater to below 1.5 mg / L, thereby ensuring that reverse osmosis does not scale.

[0019] 6. According to the water quality characteristics, the present invention can crystallize out part of sodium sulfate, which can be used for resource utilization.

[0020] 7. All self-consumed water in the recycling system of the present invention does not use fresh water, reducing the water use cost and treatment cost.

[0021] 8. The present invention returns the regenerated water of resin softening to the neutralization reaction treatment, which can reduce the lime dosage while treating the regenerated wastewater.

[0022] 9. The produced water of the present invention can meet the water replenishment requirements of the chemical water station and the circulating water station in the factory area, realizing the recycling of water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the method for collaborative treatment of rain and sewage wastewater in the non-ferrous metal resource recovery industry disclosed by the present invention; Figure 2 It is a framework diagram of a rain and sewage wastewater co-treatment system for the non-ferrous metal resource recycling industry disclosed by the present invention; Figure 3 It is a flow chart of a rain and sewage wastewater co-treatment method for the non-ferrous metal resource recycling industry disclosed by an embodiment of the present invention.

[0024] In the figure: 1. Regulation tank; 2. Coagulation and sedimentation unit; 3. First multi-media filter; 4. First ultrafiltration device; 5. Low-pressure reverse osmosis unit; 6. Waste acid tank; 7. Sulfidation reaction unit; 8. Neutralization reaction unit; 9. Softening unit; 10. Second multi-media filter; 11. Second ultrafiltration device; 12. Resin softening unit; 13. Medium-pressure reverse osmosis unit; 14. High-pressure reverse osmosis unit; 15. Evaporation and crystallization unit. Specific embodiments

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] The present invention will be further described in detail below with reference to the accompanying drawings: As Figure 1 shown, the present invention provides a rain and sewage wastewater co-treatment method for the non-ferrous metal resource recycling industry. The rain and sewage wastewater includes rainwater, general production wastewater, waste acid wastewater and acidic wastewater. The co-treatment method includes: S1. Collect rainwater and general production wastewater into the regulation tank, fully mix and homogenize them to reduce the risk of water quality fluctuation; S2. Carry out coagulation and sedimentation treatment on the wastewater in the regulation tank to remove impurities such as suspended solids and colloids in the wastewater, and the generated sludge is used as general solid waste; S3. Carry out first multi-media filtration on the water produced after coagulation and sedimentation to remove the SS that has not been completely precipitated in the wastewater, so as to ensure the stable operation of the ultrafiltration device; S4. Carry out first ultrafiltration on the water produced after the first multi-media filtration. The ultrafiltration further removes insoluble substances in the wastewater. The SDI of the water produced by the first ultrafiltration can be ensured to be no higher than 5, so as to ensure the normal operation of the low-pressure reverse osmosis; S5. Carry out low-pressure reverse osmosis desalination treatment on the water produced after the first ultrafiltration. The water produced after desalination can be directly reused as recycled water to the factory area, and the concentrated water with high salt content is used as the lime preparation water for waste acid wastewater and acidic wastewater; S6. Collect the acid wastewater and acid wastewater into the acid wastewater tank, mix and homogenize them thoroughly to reduce the risk of water quality fluctuations; S7. The wastewater in the waste acid tank is subjected to a sulfidation reaction treatment. The heavy metals and arsenic ions are combined with the sulfiding agent and precipitated in the form of sulfided slag, which is treated as hazardous waste to remove the heavy metals and arsenic ions in the wastewater. The removal rate of heavy metals and arsenic ions is as high as over 98%; S8, neutralizing the produced water after the sulfidation reaction with lime milk; wherein the lime milk is prepared by lime and pharmaceutical water; by adding lime to neutralize the sulfuric acid in the wastewater, the lime can be dissolved by rainwater and high-salt concentrated water after low-pressure reverse osmosis of general production wastewater, and added to the produced water after the sulfidation reaction in the form of lime milk. A large amount of Ca2+ is also introduced during the neutralization process. 2+ , Ca 2+ Combined with sulfate ions, it generates a large amount of calcium sulfate precipitation, which can be recycled to the production unit depending on its quality; S9, softening the produced water after the neutralization reaction; softening the remaining high-salt concentrated water after low-pressure reverse osmosis, the backwash wastewater of the second multi-media filter, the backwash wastewater of the second ultrafiltration device, the flushing wastewater of the weak cationic resin of the resin softening unit and the regeneration wastewater; and directly collecting part of the acidic wastewater into the sewage regulating tank, fully mixing and homogenizing, and then softening; wherein, by adding liquid alkali and soda ash, the calcium and magnesium hardness in the wastewater is removed, the calcium and magnesium ions are combined with carbonate or hydroxide to form a precipitate, and the softening slag is treated as general solid waste; the total hardness of the produced water of the softening reaction does not exceed 150mg / L, and SS≤30mg / L; S10, subjecting the produced water after the softening reaction to a second multi-media filtration to remove the SS that has not been completely precipitated in the wastewater, thereby ensuring the stable operation of the ultrafiltration device; S11, subjecting the produced water after the second multi-media filtration to a second ultrafiltration, wherein the ultrafiltration further removes insoluble matter in the wastewater, and the SDI of the produced water after the ultrafiltration can be guaranteed to be no higher than 5, thereby ensuring the normal operation of the low-pressure reverse osmosis; S12, the water produced after the second ultrafiltration is subjected to resin softening treatment; wherein the resin softening treatment is to selectively exchange the weak acid cation exchange resin in the resin tank to remove the residual Ca in the concentrated brine. 2+ Mg 2+ Further removal is performed to prevent the calcium and magnesium ions from multiplying during high concentration, which may lead to fouling of the reverse osmosis membrane. S13, the produced water softened by the resin is subjected to medium-pressure reverse osmosis desalination treatment, and the produced water after desalination can be directly reused in the factory as recycled water; S14, subjecting the concentrated water with high salt content after medium-pressure reverse osmosis to high-pressure reverse osmosis concentration treatment, and the high-pressure reverse osmosis continues to concentrate the wastewater, and the produced water of the high-pressure reverse osmosis can be directly reused in the factory as recycled water; S15. The concentrated water after high-pressure reverse osmosis is subjected to evaporation crystallization treatment. The condensed steam during evaporation is used as recycled water and can be directly recycled to the factory area, and the salt (sodium sulfate) crystallized out by evaporation is utilized resourcefully.

[0027] As Figure 2 shown, the present invention provides a method for co-treatment of rain and sewage wastewater in the non-ferrous metal resource recycling industry, which is used to implement the above-mentioned method for co-treatment of rain and sewage wastewater in the non-ferrous metal resource recycling industry. The rain and sewage wastewater includes rainwater, general production wastewater, waste acid wastewater, and acidic wastewater. The co-treatment system includes: A regulating tank 1, a coagulation sedimentation unit 2, a first multi-media filter 3, a first ultrafiltration device 4, and a low-pressure reverse osmosis unit 5 arranged in sequence along the treatment direction of rainwater and general production wastewater. The water produced by the low-pressure reverse osmosis is used as recycled water, and the concentrated water of the low-pressure reverse osmosis is used as the lime preparation water for waste acid wastewater and acidic wastewater; A waste acid tank 6, a sulfidation reaction unit 7, a neutralization reaction unit 8, a softening unit 9, a second multi-media filter 10, a second ultrafiltration device 11, a resin softening unit 12, a medium-pressure reverse osmosis unit 13, a high-pressure reverse osmosis unit 14, and an evaporation crystallization unit 15 arranged in sequence along the treatment direction of waste acid wastewater and acidic wastewater; the condensed steam during evaporation is used as recycled water, and the salt crystallized out by evaporation is utilized resourcefully; among them, lime milk is added to the neutralization reaction unit, and the lime milk is prepared by lime and the preparation water. Example

[0028] The rain and sewage wastewater of a comprehensive utilization project for recycling of multiple metal resources is treated by using the present invention; among them, This project is a zero-discharge project for clean wastewater and process wastewater in the whole factory area. The clean wastewater includes initial rainwater, concentrated water from water softening, indirect cooling drainage, workshop wash water, floor flushing water, etc.; the process wastewater includes waste acid wastewater, gold separation wastewater, silver separation wastewater after workshop treatment, acid mist absorption wastewater, laboratory wastewater, drying wastewater, car and bag washing leachate, etc.

[0029] (1) Inlet water quality: Clean wastewater: The pH is 6 - 7, showing neutrality; the COD is about 20 mg / L; the total salt content is about 1000 mg / L; the calcium ion content is about 25 mg / L; the magnesium ion content is about 11 mg / L; the sulfate content is 80 mg / L; the chloride content is 150 mg / L; Waste acid wastewater: containing 3% - 4% sulfuric acid; COD is about 50 mg / L; zinc ion content is about 6000 mg / L; nickel ion content is about 200 mg / L; copper ion content is about 2000 mg / L; silver ion content is about 1.0 mg / L; arsenic ion content is about 5000 mg / L; chloride ion content is about 3000 mg / L; fluoride ion content is about 2300 mg / L; (2)Effluent quality: The produced water meets the "Quality Standards for Industrial Reclaimed Water for Urban Sewage Reuse - Raw Water" (GB / T 19923 - 2005) for process and product water, as shown in Table 1; the produced water meets the requirements of the "Pollutant Discharge Standards for the Regenerated Copper, Aluminum, Lead, and Zinc Industries" (GB 31574 - 2015), as shown in Table 2; the hydrogen sulfide emission from the decontamination tower in the sulfide area of the produced water meets the requirements of the "Odor Pollutant Discharge Standards" (GB 14554 - 93). The emission rate is less than 0.33 kg / h, and the high - salinity water is equipped with an MVR evaporation device.

[0030] Table 1

[0031] Table 2

[0032] (3)Specific methods and systems for co - treating rain and sewage wastewater, including: 1) The treatment process for clean wastewater is as follows: Initial rainwater, workshop wash water, floor flushing water, concentrated chemical water, and indirect cooling drainage are collected into the clean wastewater regulation tank. After staying and homogenizing in the clean wastewater regulation tank, they are pumped to the coagulation and sedimentation unit. By adding sodium sulfide, liquid caustic soda, PFS, PAM, etc., heavy metals and suspended solids in the water are removed. The sediment after coagulation and sedimentation is subjected to pressure filtration and anode plate casting. The heavy metal removal rate of the produced water is not less than 99%, and the suspended solids do not exceed 30 mg / L.

[0033] The effluent from the coagulation and sedimentation reaction is sent into the first multi - media filter through a centrifugal pump. In the first multi - media filter, suspended particles and colloidal substances are further removed. After the produced water from the first multi - media filtration is intercepted and filtered by the first ultra - filtration device (ultra - filtration membrane), suspended solids, colloids, microorganisms, etc. in the water are removed. The effluent turbidity < 0.2 NTU, SDI < 5, ensuring the normal and stable operation of the subsequent low - pressure reverse osmosis unit.

[0034] Low - pressure reverse osmosis is used to desalt the wastewater. The produced water can reach the reclaimed water standard and is sent to the reclaimed water production tank. The TDS of the concentrated water from low - pressure reverse osmosis is about 4000 mg / L, which can be used as the lime - mixing water for the process wastewater system to prepare lime milk and be added to the neutralization reaction unit of the process wastewater.

[0035] 2) The treatment process for process wastewater is as follows: Waste acid wastewater, gold separation wastewater, silver separation wastewater, and leachate from car washing and bag washing are collected in the waste acid tank and then sent to the sulfidation reaction unit. By adding a sulfiding agent to the reaction tank of the sulfidation reaction unit, arsenic sulfide precipitation is formed with arsenic ions. The wastewater after the reaction enters the thickener, and the residence time of the wastewater in the thickener is not less than 12 h. The precipitate accumulates at the bottom of the thickening tank and is pumped to the dehydration system. The arsenic-containing sludge filtered out is treated as hazardous waste, and the hydrogen sulfide generated during the reaction is absorbed and treated; the removal rate of arsenic ions and heavy metals in the effluent from the sulfidation reaction is not less than 98%.

[0036] The effluent from the sulfidation reaction is sent to the neutralization reaction unit. By adding lime to adjust the pH of the wastewater, the pH is adjusted to 3 - 8. During this process, a large amount of calcium fluoride precipitation will be produced with fluoride ions, and the fluoride ions in the raw water are removed. The fluoride ions in the effluent do not exceed 20 mg / L; at the same time, sulfate ions and calcium ions also precipitate in the form of gypsum, and the gypsum can be treated as general solid waste. The clear liquid is sent to the softening unit for softening treatment.

[0037] Acid mist absorption wastewater, laboratory wastewater, and drying wastewater are sent to the sewage adjustment tank. After aeration, mixing, and homogenization in the sewage adjustment tank, they are sent to the softening unit for softening treatment; at the same time, the backwash wastewater of the second multi-media filter, the backwash wastewater of the second ultrafiltration device (ultrafiltration membrane), the flushing wastewater and regeneration wastewater of the weak cation resin in the resin softening unit in the process wastewater system are also sent to the softening unit; in the softening unit, the pH of the influent is adjusted by adding sodium hydroxide, and soda solution is added to react with CO2, HCO 3- 、Ca 2+ 、Mg 2+ to generate CaCO3 and Mg(OH)2 precipitates. At the same time, PFS and PAM are added to make the precipitates form larger flocs, so as to effectively remove the suspended solids in the effluent. The total hardness of calcium and magnesium in the effluent from the softening reaction does not exceed 120 mg / L, the alkalinity content is about 300 mg / L, and the SS is not higher than 30 mg / L. Finally, after adjusting the pH by adding acid to the effluent area, the effluent is collected through the collection tank and enters the subsequent treatment structures.

[0038] The effluent from the softening unit enters the second multi-media filter through a centrifugal pump, and suspended particles and colloidal substances are further removed in the second multi-media filter. After the water produced by the second multi-media filter is intercepted and filtered by the second ultrafiltration device (ultrafiltration membrane), suspended solids, colloids, microorganisms, etc. in the water are effectively removed, and the effluent turbidity < 0.2 NTU, SDI < 5, ensuring the normal and stable operation of the subsequent treatment system.

[0039] The effluent from the second ultrafiltration device enters the weak acid cation bed. The weak acid cation bed, through the selective exchange action of the cation exchange resin in the resin tank, removes the residual Ca 2+ 、Mg2+ Thorough removal is carried out, and the total hardness of the water produced by the weak acid cation exchanger is not higher than 1.5 mg / L; ensure the long-term stable operation of the whole set of equipment.

[0040] The water produced by the weak acid cation exchanger is subjected to secondary concentration and desalination treatment through medium-pressure reverse osmosis and high-pressure reverse osmosis. The produced water part is sent to the reused water tank for reuse in the plant area. The high-concentration brine TDS is concentrated to 100,000 mg / L and sent to MVR evaporation crystallization. The steam condensate water of MVR is sent to the reused water tank for reuse in the plant area, and the sodium sulfate produced by MVR can be utilized resourcefully.

[0041] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for co - treating rain and sewage wastewater in the non - ferrous metal resource recovery industry. The rain and sewage wastewater includes rainwater, general production wastewater, waste acid wastewater, and acidic wastewater, and is characterized in that, The co-treatment method includes: Collect rainwater and general production wastewater into the regulation tank, and fully mix and homogenize them; Perform coagulation and sedimentation treatment on the wastewater in the regulation tank; Perform first multi-media filtration on the water produced after coagulation and sedimentation; Perform first ultrafiltration on the water produced after the first multi-media filtration; Perform low-pressure reverse osmosis desalination treatment on the water produced after the first ultrafiltration. The desalinated water is used as recycled water, and the high-salt-content concentrated water is used as the lime dosing water for waste acid wastewater and acidic wastewater; Collect waste acid wastewater and acidic wastewater into the waste acid tank, and fully mix and homogenize them; Perform sulfidation reaction treatment on the wastewater in the waste acid tank; Perform neutralization treatment on the water produced after the sulfidation reaction with lime milk; wherein, the lime milk is prepared by mixing lime with the dosing water; Perform softening treatment on the water produced after the neutralization reaction; Perform second multi-media filtration on the water produced after the softening reaction; Perform second ultrafiltration on the water produced after the second multi-media filtration; Perform resin softening treatment on the water produced after the second ultrafiltration; Perform medium-pressure reverse osmosis desalination treatment on the water produced after resin softening. The desalinated water is used as recycled water; Perform high-pressure reverse osmosis concentration treatment on the high-salt-content concentrated water after medium-pressure reverse osmosis. The water produced by high-pressure reverse osmosis is used as recycled water; Perform evaporation and crystallization treatment on the concentrated water after high-pressure reverse osmosis. The condensed steam during evaporation is used as recycled water, and the salt crystallized out by evaporation is utilized resourcefully.

2. The co-treatment method for rain and sewage wastewater in the non-ferrous metal resource recycling industry according to claim 1, characterized in that, It also includes: Perform softening treatment on the remaining high-salt-content concentrated water after low-pressure reverse osmosis, the backwash wastewater of the second multi-media filter, the backwash wastewater of the second ultrafiltration device, the flushing wastewater and regeneration wastewater of the weak cation resin in the resin softening unit.

3. The collaborative treatment method for rain and sewage wastewater in the non-ferrous metal resource recycling industry according to claim 1 or 2, characterized in that, The effluent turbidity of the water produced by the first ultrafiltration is <0.2 NTU, and the SDI <5.

4. The co-treatment method for rain and sewage wastewater in the non-ferrous metal resource recycling industry according to claim 1 or 2, characterized in that, The sulfidation reaction treatment of the wastewater in the waste acid tank includes: Send the wastewater in the waste acid tank into the reaction tank, add a sulfiding agent to the reaction tank, and the sulfiding agent forms arsenic sulfide precipitate with the arsenic ions in the wastewater; the reacted wastewater enters the thickener, and the residence time of the wastewater in the thickener is not less than 12 h. The precipitate accumulates at the bottom of the thickener and is pumped to the dehydration system, and the arsenic-containing sludge filtered out by pressure filtration is treated as hazardous waste; the removal rate of arsenic ions and heavy metals in the effluent of the sulfidation reaction is not less than 98%.

5. The co-treatment method for rain and sewage wastewater in the non-ferrous metal resource recovery industry according to claim 1 or 2, characterized in that, The neutralization treatment of the water produced after the sulfidation reaction with lime milk includes: Adjust the pH of the wastewater by adding lime milk, and adjust the pH to 3-8; wherein, the lime is dissolved by the high-salt-content concentrated water after low-pressure reverse osmosis of rainwater and general production wastewater to obtain lime milk; during this process, fluoride ions react with calcium to produce a precipitate to remove fluoride ions in the raw water, so that the fluoride ions in the effluent do not exceed 20 mg / L; at the same time, sulfate ions also precipitate in the form of gypsum, and the gypsum is treated as general solid waste, and the supernatant is subjected to subsequent softening treatment.

6. The co-treatment method for rain and sewage wastewater in the non-ferrous metal resource recycling industry according to claim 1 or 2, characterized in that, It also includes: Directly collect part of the acidic wastewater into the sewage regulation tank, fully mix and homogenize it, and then perform softening treatment.

7. A method for co - treating rain and sewage wastewater in the non - ferrous metal resource recovery industry, which is used to implement the method for co - treating rain and sewage wastewater in the non - ferrous metal resource recovery industry as described in any one of claims 1 to 6. The rain and sewage wastewater includes rainwater, general production wastewater, waste acid wastewater, and acidic wastewater, and is characterized in that, The co-treatment system includes: A regulating tank, a coagulation and sedimentation unit, a first multi-media filter, a first ultrafiltration device, and a low-pressure reverse osmosis unit are arranged in sequence along the treatment direction of rainwater and general production wastewater. The produced water of the low-pressure reverse osmosis is used as recycled water, and the concentrated water of the low-pressure reverse osmosis is used as the lime preparation water for waste acid wastewater and acidic wastewater. A waste acid tank, a sulfidation reaction unit, a neutralization reaction unit, a softening unit, a second multi-media filter, a second ultrafiltration device, a resin softening unit, a medium-pressure reverse osmosis unit, a high-pressure reverse osmosis unit, and an evaporation and crystallization unit are arranged in sequence along the treatment direction of waste acid wastewater and acidic wastewater; the condensed steam from evaporation is used as recycled water, and the salts crystallized out by evaporation are utilized resourcefully; among them, lime milk is added in the neutralization reaction unit, and the lime milk is prepared by mixing lime with the preparation water.

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