Method for treating reverse osmosis concentrated water

Abstract

The invention provides a reverse osmosis concentrated water treatment method, which comprises: sequentially carrying out electrolytic treatment, heterogeneous adsorption treatment and reverse osmosis treatment on reverse osmosis concentrated water to obtain clean water. According to the invention, the hardness and the content of microorganisms and organic pollutants in the reverse osmosis concentrated water are reduced by utilizing electrolytic treatment, and the addition of chemical reagents is avoided; then, substances which possibly have negative effects on the reverse osmosis membrane in electrolysis products are removed through heterogeneous adsorption treatment, an adopted adsorbent can be recycled, and the long-term cost is low; and finally, the reverse osmosis concentrated water is recycled through reverse osmosis treatment, so that the industrial water-saving effect is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, and particularly relates to a treatment method for reverse osmosis concentrated water. BACKGROUND

[0002] The water source of industrial circulating water is complex, and part of the circulating water (such as reclaimed water, seawater, and high-salinity underground water) has high salinity. The conventional pretreatment (coagulation and filtration) cannot remove ions, and therefore, desalination by a reverse osmosis membrane is required to ensure that the water quality of the water source meets the basic requirements of the circulating water. The recovery rate of the reverse osmosis technology for clean water is related to the water quality, and the actual recovery rate of an industrial reverse osmosis device can reach more than 75%, which is much higher than the recovery rate of a small device. Even so, the large amount of use of the industrial circulating water still causes a large amount of concentrated water during the operation of the reverse osmosis system. Therefore, it is of great industrial significance to find a stable and efficient recovery method for the reverse osmosis concentrated water.

[0003] At present, the recovery of the reverse osmosis concentrated water is usually achieved by secondary reverse osmosis or multi-stage reverse osmosis. However, the water quality of the reverse osmosis concentrated water is much more complex than that of the raw water of the water source, and the concentration of the pollutants is high and the composition is special. First, the highly concentrated hardness and salt in the concentrated water are prone to scale and precipitation on the reverse osmosis membrane, which reduces the treatment efficiency of the reverse osmosis membrane or even causes membrane blockage; the microorganisms and concentrated organic matter also cause membrane pollution and reduce the treatment efficiency. In order to solve this problem, it is usually necessary to add chemical reagents such as organic scale inhibitors (such as phosphonate and carboxylic acid) and bactericides (such as sodium hypochlorite and non-oxidizing bactericides) to the concentrated water for pretreatment to ensure the safety of the membrane. These reagents can form organic-inorganic composite pollutants in the concentrated water, which can also damage the treatment performance of the reverse osmosis membrane. In addition, the concentrated water may contain concentrated suspended particles, which will further aggregate due to the "concentration effect" in the secondary reverse osmosis system, forming "colloidal pollution" and accelerating the deactivation of the reverse osmosis membrane.

[0004] CN102139984A discloses a reverse osmosis concentrated water treatment method and a reverse osmosis concentrated water treatment system. The method comprises heating the reverse osmosis concentrated water; passing the heated reverse osmosis concentrated water into a membrane distillation assembly for membrane distillation treatment to obtain water vapor; passing the water vapor into a vapor-liquid separator to separate water droplets mixed in the water vapor; passing the water vapor into a heat exchanger to condense the water vapor into primary pure water; and passing the primary pure water into an electrodeionization membrane stack for electrodeionization treatment to obtain high-purity water.

[0005] CN101993162A discloses a reverse osmosis concentrated water treatment method, relates to a treatment method of high-concentration refractory organic wastewater, and comprises the following steps: step 1, adjusting the pH value of the reverse osmosis concentrated water to be between 6.5-7.5; step 2, coagulation and sedimentation, removing part of the suspended solids, colloids and impurities in the reverse osmosis concentrated water; step 3, carbon black-ultrasonic-Fenton oxidation; step 4, sedimentation: the reverse osmosis concentrated water treated by the carbon black-ultrasonic-Fenton oxidation is introduced into a sedimentation tank, alkali is added into the sedimentation tank, the pH value is adjusted to be between 8-8.5, and sedimentation treatment is carried out to realize solid-liquid separation.

[0006] CN103145296A discloses a reverse osmosis concentrated water treatment method and a treatment system thereof, comprising the following steps: (1) the reverse osmosis concentrated water is first introduced into a pH adjusting tank; (2) the reverse osmosis concentrated water treated by the pH adjusting tank is introduced into a photocatalytic oxidation unit to carry out photocatalytic oxidation reaction; (3) the effluent treated by the photocatalytic oxidation unit is introduced into a neutralization reaction tank to adjust the pH value to be 6-8; (4) the effluent treated by the neutralization reaction tank is introduced into a coagulation tank, and a coagulant is added into the coagulation tank to make the colloidal particles in the reverse osmosis concentrated water coagulate with each other; (5) the effluent treated by the coagulation tank is introduced into a sedimentation tank to carry out solid-liquid separation to remove the organic colloidal particles remaining in the reverse osmosis concentrated water after the photocatalytic oxidation reaction; and (6) the effluent treated by the sedimentation tank is discharged after passing through a filter.

[0007] However, the reverse osmosis concentrated water treatment method has the problems of high treatment cost, the need of adding coagulation agents, and the need of additional treatment of the generated sediments. SUMMARY

[0008] In view of the problems in the prior art, the present application provides a reverse osmosis concentrated water treatment method, which uses electrolysis technology for the pretreatment of the reverse osmosis concentrated water, and reduces the hardness, microorganisms and organic pollutants in the concentrated water in one step, thereby avoiding the pollution problems caused by chemical pretreatment; then, non-homogeneous adsorption treatment and reverse osmosis treatment are sequentially carried out to obtain clean water at a low cost, and the goal of industrial water saving is achieved.

[0009] To achieve the above object, the present application adopts the following technical scheme:

[0010] The present application provides a reverse osmosis concentrated water treatment method, which comprises sequentially carrying out electrolysis treatment, non-homogeneous adsorption treatment and reverse osmosis treatment on the reverse osmosis concentrated water to be treated to obtain clean water.

[0011] The TDS in the clean water is <150 mg / L, the total hardness is <20 mg / L, the chloride ion content is <50 mg / L, the HCO3 - content is <10 mg / L, and the COD is <4 mg / L.

[0012] The reverse osmosis concentrated water treatment method has reasonable design, simple operation and low treatment cost. - , CO3 2- , and calcium and magnesium ions form a precipitate to remove hardness from the water; active chlorine with strong oxidizing property is generated at the anode to cooperatively remove microorganisms and organic pollutants in the reverse osmosis concentrated water; after electrolysis, the concentrated water is subjected to heterogeneous adsorption treatment to remove suspended particles floating in the concentrated water, intercept scale drifting from the cathode, and consume unreacted active chlorine, so as to achieve the purpose of relieving subsequent chemical damage to the reverse osmosis membrane.

[0013] The treatment object of the present application is reverse osmosis concentrated water obtained by pretreatment and reverse osmosis membrane treatment of surface water or municipal tap water.

[0014] The TDS in the clean water is < 150 mg / L, for example, it can be 149 mg / L, 145 mg / L, 140 mg / L, 120 mg / L or 100 mg / L, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0015] The total hardness is < 20 mg / L, for example, it can be 19 mg / L, 18 mg / L, 15 mg / L, 13 mg / L or 10 mg / L, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0016] The chloride ion content is < 50 mg / L, for example, it can be 49 mg / L, 45 mg / L, 40 mg / L, 30 mg / L or 20 mg / L, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0017] The HCO3 - content is < 10 mg / L, for example, it can be 9 mg / L, 8 mg / L, 7 mg / L, 5 mg / L or 2 mg / L, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0018] The COD is < 4 mg / L, for example, it can be 3.9 mg / L, 3.5 mg / L, 3 mg / L, 2.5 mg / L or 1 mg / L, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0019] Preferably, the TDS of the reverse osmosis concentrated water to be treated is 800-4000 mg / L, for example, it can be 800 mg / L, 1000 mg / L, 1500 mg / L, 2500 mg / L, 3500 mg / L or 4000 mg / L, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0020] The total hardness is 400-800 mg / L, for example, it can be 400 mg / L, 500 mg / L, 600 mg / L, 700 mg / L or 800 mg / L, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0021] The chloride ion content is 200-1000 mg / L, for example, it can be 200 mg / L, 300 mg / L, 500 mg / L, 600 mg / L, 800 mg / L or 1000 mg / L, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0022] The HCO3 - content is 100-600 mg / L, for example, it can be 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, 500 mg / L or 600 mg / L, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0023] The COD is 5-80 mg / L, for example, it can be 5 mg / L, 10 mg / L, 20 mg / L, 40 mg / L, 60 mg / L or 80 mg / L, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0024] Preferably, the anode in the electrolytic treatment comprises a ruthenium iridium titanium electrode or a graphite electrode.

[0025] Preferably, the cathode in the electrolytic treatment comprises any one of a stainless steel plate, a titanium plate or a graphite electrode.

[0026] Preferably, the pH of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 7.5-9.0, for example, it can be 7.5, 7.7, 7.9, 8.1, 8.5 or 9.0, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0027] Preferably, the temperature of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 12-30℃, for example, it can be 12℃, 15℃, 18℃, 21℃, 25℃ or 30℃, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0028] Preferably, the device for electrolytic treatment comprises an automatic scale removal device arranged at the cathode, which timely removes scale on the surface of the cathode, thereby ensuring long-term stable operation of the cathode.

[0029] Preferably, the adsorbent used in the heterogeneous adsorption treatment comprises a mixture of activated carbon or quartz sand and calcium sulfite, which can adsorb and remove suspended solids and active chlorine in the concentrated water, and has low treatment cost.

[0030] Preferably, the empty bed contact time of the heterogeneous adsorption treatment is 5-15 min, for example, it can be 5 min, 7 min, 9 min, 11 min, 13 min or 15 min, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0031] Preferably, the particle size of the activated carbon is 8-40 mesh, for example, it can be 8 mesh, 12 mesh, 16 mesh, 20 mesh, 30 mesh or 40 mesh, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0032] Preferably, the activated carbon comprises any one or a combination of at least two of coal-based activated carbon, nut shell-based activated carbon or wood-based activated carbon, wherein a typical but non-limiting combination includes a combination of coal-based activated carbon and nut shell-based activated carbon, a combination of wood-based activated carbon and coal-based activated carbon, or a combination of nut shell-based activated carbon and wood-based activated carbon.

[0033] Preferably, in the mixture of quartz sand and calcium sulfite, the mass ratio of calcium sulfite to residual chlorine in the water after electrolytic treatment is (1.8-2.5):1, for example, it can be 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.3:1 or 2.5:1, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0034] Preferably, the particle size of the quartz sand is 0.5-1.0 mm, for example, it can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1.0 mm, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0035] Preferably, the concentrated water produced by the reverse osmosis treatment is mixed with the reverse osmosis concentrated water to be treated for cyclic treatment.

[0036] Preferably, when the reverse osmosis treatment produces concentrated water TDS > 70000 mg / L, for example, it can be 70010 mg / L, 70030 mg / L, 70050 mg / L, 71000 mg / L, 72000 mg / L or 75000 mg / L, etc., but not limited to the listed values, other values in the range of the value range are also applicable;

[0037] Or total hardness > 5000 mg / L, for example, it can be 5001 mg / L, 5010 mg / L, 5020 mg / L, 5050 mg / L, 5080 mg / L or 5200 mg / L, etc., but not limited to the listed values, other values in the range of the value range are also applicable; discharge or drying. By drying the high TDS or high hardness concentrated water produced by reverse osmosis treatment, near-zero discharge of wastewater can be achieved, and pollution of wastewater can be reduced.

[0038] As a preferred technical solution of the present application, the treatment method comprises:

[0039] The reverse osmosis concentrated water to be treated is sequentially subjected to electrolytic treatment, heterogeneous adsorption treatment and reverse osmosis treatment to obtain clean water;

[0040] The TDS of the reverse osmosis concentrated water to be treated is 800-4000 mg / L, the total hardness is 400-800 mg / L, the chloride ion content is 200-1000 mg / L, the HCO3 - Content is 100-600 mg / L, and the COD is 5-80 mg / L;

[0041] The anode in the electrolytic treatment comprises a ruthenium-iridium-titanium electrode or a graphite electrode; the cathode in the electrolytic treatment comprises any one of a stainless steel plate, a titanium plate or a graphite electrode; the pH of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 7.5-9.0; the temperature of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 12-30℃; the device for electrolytic treatment comprises an automatic scale removal device arranged at the cathode;

[0042] The adsorbent used in the heterogeneous adsorption treatment comprises a mixture of activated carbon or quartz sand and calcium sulfite; the empty bed contact time of the heterogeneous adsorption treatment is 5-15 min; the particle size of the activated carbon is 8-40 mesh; the activated carbon comprises any one of coal-based activated carbon, shell-based activated carbon or wood-based activated carbon or a combination of at least two thereof; in the mixture of quartz sand and calcium sulfite, the mass ratio of calcium sulfite to residual chlorine in the water after electrolytic treatment is (1.8-2.5):1; the particle size of the quartz sand is 0.5-1.0 mm;

[0043] The concentrated water generated by the reverse osmosis treatment is mixed with the reverse osmosis concentrated water to be treated to perform a cyclic treatment; when the TDS of the concentrated water generated by the reverse osmosis treatment is greater than 70000 mg / L or the total hardness is greater than 5000 mg / L, the concentrated water is discharged or dried;

[0044] The TDS of the cleaning water is less than 150 mg / L, the total hardness is less than 20 mg / L, the chloride ion content is less than 50 mg / L, the HCO3 - content is less than 10 mg / L, and the COD is less than 4 mg / L.

[0045] Compared with the prior art, the application has at least the following beneficial effects:

[0046] The reverse osmosis concentrated water treatment method provided by the application is reasonable in design and low in treatment cost, the reverse osmosis concentrated water is first treated by electrolysis, the concentration of hardness, microorganisms and organic pollutants in the concentrated water is reduced in one step, and the pollution problem caused by chemical treatment is effectively avoided; then, the reverse osmosis concentrated water is treated by heterogeneous adsorption treatment and reverse osmosis treatment which are simple to operate and low in long-term treatment cost, the reverse osmosis concentrated water is recycled, clean water is obtained, industrial water saving is achieved, and the application is suitable for wide range of popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a schematic diagram of a reverse osmosis concentrated water treatment device system in embodiment 1 of the application.

[0048] In the figure: 1-electrolysis device; 2-heterogeneous adsorption device; 3-reverse osmosis membrane group; 4-buffer tank. DETAILED DESCRIPTION

[0049] The technical solutions of the application will be further described below with reference to the drawings and through specific embodiments.

[0050] The application will be further described below. However, the following examples are only simple examples of the application and do not represent or limit the protection scope of the application, and the protection scope of the application is subject to the claims.

[0051] Embodiment 1

[0052] The embodiment provides a reverse osmosis concentrated water treatment method, and the treatment method comprises the following steps:

[0053] The reverse osmosis concentrated water to be treated is sequentially subjected to electrolysis treatment, heterogeneous adsorption treatment and reverse osmosis treatment to obtain clean water;

[0054] The TDS of the reverse osmosis concentrated water to be treated is 2500 mg / L, the total hardness is 600 mg / L, the chloride ion content is 800 mg / L, the HCO3 - content is 400 mg / L, and the COD is 30 mg / L.

[0055] The anode in the electrolytic treatment is a ruthenium iridium titanium electrode; the cathode in the electrolytic treatment is a stainless steel plate; the pH of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 8.0; the temperature of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 25℃; the device for the electrolytic treatment comprises an automatic scale scraping device arranged at the cathode;

[0056] The adsorbent used in the heterogeneous adsorption treatment is activated carbon; the empty bed contact time of the heterogeneous adsorption treatment is 10 min; the particle size of the activated carbon is 30 mesh; the activated carbon is coal-based activated carbon;

[0057] The concentrated water produced by the reverse osmosis treatment is mixed with the reverse osmosis concentrated water to be treated for cyclic treatment; when the TDS of the concentrated water produced by the reverse osmosis treatment is >70000 mg / L or the total hardness is >5000 mg / L, it is discharged.

[0058] The reverse osmosis concentrated water treatment method described in the embodiment is carried out by using the reverse osmosis concentrated water treatment device system as follows; the schematic diagram of the reverse osmosis concentrated water treatment device system is shown in Figure 1 .

[0059] The treatment device system comprises an electrolytic device 1, a heterogeneous adsorption device 2 and a reverse osmosis membrane group 3 connected in sequence; a buffer tank 4 is further arranged between the heterogeneous adsorption device 2 and the reverse osmosis membrane group 3.

[0060] Example 2

[0061] The embodiment provides a reverse osmosis concentrated water treatment method, which comprises:

[0062] The reverse osmosis concentrated water to be treated is sequentially subjected to electrolytic treatment, heterogeneous adsorption treatment and reverse osmosis treatment to obtain clean water;

[0063] The TDS of the reverse osmosis concentrated water to be treated is 3500 mg / L, the total hardness is 800 mg / L, the chloride ion content is 1000 mg / L, the HCO3 - content is 600 mg / L, and the COD is 60 mg / L;

[0064] The anode in the electrolytic treatment is a graphite electrode; the cathode in the electrolytic treatment is a titanium plate; the pH of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 7.5; the temperature of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 12℃; the device for the electrolytic treatment comprises an automatic scale scraping device arranged at the cathode;

[0065] The adsorbent used in the heterogeneous adsorption treatment is a mixture of quartz sand and calcium sulfite; the empty bed contact time of the heterogeneous adsorption treatment is 15 min; in the mixture of quartz sand and calcium sulfite, the mass ratio of calcium sulfite to residual chlorine in the water after electrolytic treatment is 2.0:1; the particle size of the quartz sand is 1.0 mm;

[0066] The concentrated water generated by the reverse osmosis treatment is mixed with the reverse osmosis concentrated water to be treated for cyclic treatment; when the TDS of the concentrated water generated by the reverse osmosis treatment is >70000 mg / L or the total hardness is >5000 mg / L, drying is performed.

[0067] Example 3

[0068] The present embodiment provides a treatment method for reverse osmosis concentrated water, which comprises:

[0069] The reverse osmosis concentrated water to be treated is sequentially subjected to electrolytic treatment, heterogeneous adsorption treatment and reverse osmosis treatment to obtain clean water;

[0070] The TDS of the reverse osmosis concentrated water to be treated is 1200 mg / L, the total hardness is 400 mg / L, the chloride ion content is 200 mg / L, the HCO3 - content is 200 mg / L, and the COD is 5 mg / L;

[0071] The anode in the electrolytic treatment is a ruthenium-iridium-titanium electrode; the cathode in the electrolytic treatment is a graphite electrode; the pH of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 9.0; the temperature of the reverse osmosis concentrated water to be treated in the electrolytic treatment is 30℃; the device for electrolytic treatment comprises an automatic scale removal device arranged at the cathode;

[0072] The adsorbent used in the heterogeneous adsorption treatment is a mixture of quartz sand and calcium sulfite; the empty bed contact time of the heterogeneous adsorption treatment is 5 min; in the mixture of quartz sand and calcium sulfite, the mass ratio of calcium sulfite to residual chlorine in the water after electrolytic treatment is 2.2:1; the particle size of the quartz sand is 0.5 mm;

[0073] The concentrated water generated by the reverse osmosis treatment is mixed with the reverse osmosis concentrated water to be treated for cyclic treatment; when the TDS of the concentrated water generated by the reverse osmosis treatment is >70000 mg / L or the total hardness is >5000 mg / L, the concentrated water is discharged.

[0074] In summary, according to Examples 1-3, the treatment method for reverse osmosis concentrated water provided by the present application reduces the concentrations of hardness, microorganisms and organic pollutants in the concentrated water through electrolytic treatment; then, clean water is obtained through heterogeneous adsorption treatment and reverse osmosis treatment, and the TDS of the clean water is <150 mg / L, the total hardness is <20 mg / L, the chloride ion content is <50 mg / L, the HCO3- The content is <10 mg / L, and the COD is <4 mg / L, so that the reverse osmosis concentrated water is recycled, and the industrial water saving goal is achieved.

[0075] Example 4

[0076] The treatment method for the reverse osmosis concentrated water is the same as that in Example 1, except that the pH of the reverse osmosis concentrated water to be treated in the electrolysis treatment is 7.0.

[0077] Example 5

[0078] The treatment method for the reverse osmosis concentrated water is the same as that in Example 1, except that the pH of the reverse osmosis concentrated water to be treated in the electrolysis treatment is 9.5.

[0079] It can be concluded from the comparison between Example 1 and Examples 4-5 that, in Example 4, the pH of the reverse osmosis concentrated water to be treated in the electrolysis treatment is lower than the specified pH range of 7.5-9.0 in the present application, which causes the alkaline substances generated in the cathode to be neutralized, thereby inhibiting the hardness removal process in the cathode and affecting the treatment effect of the electrolysis process; in Example 5, the pH of the reverse osmosis concentrated water to be treated in the electrolysis treatment is higher than the specified pH range of 7.5-9.0 in the present application, which causes the pH of the concentrated water after electrolysis treatment to be too high, thereby causing the risk of alkaline corrosion and scaling on the reverse osmosis membrane, and additional acid needs to be added to adjust the pH, thereby increasing the operating cost.

[0080] Comparative Example 1

[0081] The treatment method for the reverse osmosis concentrated water is the same as that in Example 1, except that the electrolysis treatment is replaced by a coagulation and sedimentation treatment, and the coagulation and sedimentation treatment uses polyaluminum chloride.

[0082] Since the coagulation and sedimentation method is used to treat the reverse osmosis concentrated water in the present comparative example, precipitates are generated, which need to be treated additionally, thereby increasing the treatment cost of the reverse osmosis concentrated water. Moreover, the flocculation method has limited effect on the removal of hardness, COD, and microorganisms in the concentrated water, and cannot protect the reverse osmosis membrane.

[0083] Comparative Example 2

[0084] The treatment method for the reverse osmosis concentrated water is the same as that in Example 1, except that no heterogeneous adsorption treatment is performed.

[0085] Since no heterogeneous adsorption treatment is performed in the present comparative example, the suspended particles floating in the concentrated water after electrolysis treatment, the scale generated from the cathode, and the unreacted active chlorine can enter the reverse osmosis membrane, which not only causes chemical damage to the reverse osmosis membrane, but also reduces the filtration efficiency of the membrane, shortens the service life of the membrane, and increases the treatment cost of the reverse osmosis concentrated water.

[0086] Comparative Example 3

[0087] The present comparative example provides a treatment method of reverse osmosis concentrated water, which is the same as example 1 except that no reverse osmosis treatment is performed.

[0088] The present comparative example does not perform reverse osmosis treatment, so the concentration of total hardness and chloride ions in the concentrated water after heterogeneous adsorption treatment is high, which does not meet the requirements of industrial circulating water, and the recovery of reverse osmosis concentrated water cannot be achieved.

[0089] In summary, the treatment method of reverse osmosis concentrated water provided by the present application is reasonable in design and low in processing cost. Firstly, the reverse osmosis concentrated water is treated by electrolysis, which reduces the concentrations of hardness, microorganisms and organic pollutants in the concentrated water in one step, avoiding the generation of additional pollutants by chemical treatment. Then, the clean water source for industrial circulating water is obtained by using heterogeneous adsorption treatment and reverse osmosis treatment, achieving industrial water saving.

[0090] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by any person skilled in the art, and all such changes or replacements fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for treating reverse osmosis concentrate, characterized in that, The processing method includes: The reverse osmosis concentrate to be treated is sequentially subjected to electrolysis, heterogeneous adsorption, and reverse osmosis to obtain clean water. The clean water has a TDS of <150 mg / L, a total hardness of <20 mg / L, a chloride ion content of <50 mg / L, and an HCO3 content of <150 mg / L. - The content is <10mg / L, and the COD is <4mg / L.

2. The processing method according to claim 1, characterized in that, The TDS of the reverse osmosis concentrate to be treated is 800-4000 mg / L, the total hardness is 400-800 mg / L, the chloride ion content is 200-1000 mg / L, and the HCO3 content is... - The content is 100-600 mg / L, and the COD is 5-80 mg / L.

3. The processing method according to claim 1 or 2, characterized in that, The anode in the electrolytic process includes a ruthenium-iridium-titanium electrode or a graphite electrode; Preferably, the cathode in the electrolytic process comprises any one of a stainless steel plate, a titanium plate, or a graphite electrode.

4. The processing method according to any one of claims 1-3, characterized in that, The pH of the reverse osmosis concentrate to be treated in the electrolysis process is 7.5-9.

0.

5. The processing method according to any one of claims 1-4, characterized in that, The temperature of the reverse osmosis concentrate to be treated in the electrolysis process is 12-30℃.

6. The processing method according to any one of claims 1-5, characterized in that, The electrolytic treatment apparatus includes an automatic scraping device located at the cathode.

7. The processing method according to any one of claims 1-6, characterized in that, The adsorbent used in the heterogeneous adsorption treatment includes activated carbon or a mixture of quartz sand and calcium sulfite. Preferably, the contact time of the empty bed in the heterogeneous adsorption treatment is 5-15 min.

8. The processing method according to claim 7, characterized in that, The activated carbon has a particle size of 8-40 mesh; Preferably, the activated carbon includes any one or a combination of at least two of coal-based activated carbon, fruit shell activated carbon, or wood-based activated carbon.

9. The processing method according to claim 7, characterized in that, In the mixture of quartz sand and calcium sulfite, the mass ratio of calcium sulfite to residual chlorine in the water after electrolytic treatment is (1.8-2.5):1; Preferably, the particle size of the quartz sand is 0.5-1.0 mm.

10. The processing method according to any one of claims 1-9, characterized in that, The concentrate produced by the reverse osmosis treatment is mixed with the reverse osmosis concentrate to be treated and then recycled. Preferably, when the concentrated water produced by reverse osmosis has a TDS > 70000 mg / L or a total hardness > 5000 mg / L, it is discharged or dried.

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