Method for treating reverse osmosis concentrated water

Abstract

The invention relates to the technical field of wastewater treatment, and provides a reverse osmosis (RO) concentrated water treatment method which comprises the following steps: step 1, treating sewage discharged by an RO concentrated water tank through a first catalytic ozonation module, a biological aerated filter module, a second catalytic ozonation module and a drainage reflux module in sequence; 2, online water quality detectors arranged at the water inlet ends of the first catalytic ozonation module, the biological aerated filter module, the second catalytic ozonation module and the drainage backflow module are used for monitoring water quality indexes in real time, and detection data are transmitted to an automatic control system; on-line water quality index detection is adopted, hysteresis of off-line detection is avoided, unattended operation, self-control operation and high process operation flexibility can be achieved, the method is suitable for application scenes with huge incoming water quality fluctuation, and parameters of the selected process module are easy to adjust and switch.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a method for treating reverse osmosis concentrated water. Background Art

[0002] The papermaking industry, like the printing and dyeing industry, steel and other industries, is a traditional major water polluter. Its sewage discharge and COD discharge are at the forefront of industrial wastewater discharge, causing serious pollution to the water environment. Because the papermaking wastewater contains salt, hardness, heavy metals and other substances, the wastewater after biochemical treatment is far from meeting the reuse requirements, so it is necessary to use reverse osmosis technology to recycle and reuse the reclaimed water. In the process of realizing the reuse of reclaimed water, the double membrane method consisting of ultrafiltration + reverse osmosis is an important way, and its effluent can meet the reuse standards of the enterprise. In the typical process flow of the double membrane process, the enterprise wastewater is treated at the front end and the effluent enters the reclaimed water reuse system. After the double membrane treatment, the membrane clear liquid replenishes the reuse water system, and the membrane concentrate water accounting for 20% to 40% of the total water volume is treated by other treatments. At present, it is generally discharged after mixing. The pollutant index concentration of the reverse osmosis membrane concentrate is relatively high, often exceeding the corresponding emission standards, so the double membrane concentrate water needs to be treated to meet the emission requirements.

[0003] 1. The patent technology with announcement number CN114212946 A discloses an RO concentrated water treatment system and treatment method. The RO concentrated water treatment system includes a membrane Fenton system, a biological activated carbon filter and / or an aerated biological filter connected in sequence. The RO concentrated water treatment system adopts an organic combination of a membrane Fenton system and a BAC and / or BAF biofilm method, each taking advantage of its own strengths and complementing each other, thereby improving the treatment effect and reducing the overall cost; the dosage of the Fenton agent can be adjusted according to the water quality of the inlet water and the requirements of the outlet water to meet different water quality and outlet water requirements.

[0004] Its advantages are to fully explore the advantages of different processes, combine different technical solutions, and complement each other's advantages. The disadvantages are that the membrane Fenton process produces a large amount of iron sludge hazardous waste, which has a high treatment cost; the strong oxidation operating environment is more demanding on the selection of membranes, and the equipment investment and operation and maintenance costs are high; after the process combination is selected by comparison of process effects, the later operation only automatically controls the dosage of reagents, and the process cannot be changed according to changes in the quality and quantity of the influent water.

[0005] 2. The patented technology with announcement number CN1769197A discloses a method for zero-discharge recycling of industrial wastewater, including pretreatment, membrane separation, concentrated liquid treatment return and sludge treatment stages. After pretreatment, the pollution index SDI of high-concentration industrial wastewater is ≤5; then, according to the requirements of clean water quality, nanofiltration membrane or reverse osmosis membrane separation is selected, and the produced water is disinfected and applied to enterprise production; the concentrated liquid is refluxed and circulated, and used for reverse / forward flushing of multi-media filters, and the concentrated liquid is flushed into the A / O tank for anaerobic-aerobic reaction, and then refluxed and circulated; the sludge is dehydrated into mud cakes for external transportation, and the water is refluxed and circulated. Compared with the existing technology, this method regenerates high-concentration industrial wastewater, and the water quality of the produced water meets the requirements of clean water quality for enterprise production, which can be directly used in production and use, realizing zero discharge and recycling of industrial wastewater, and the water production cost of regeneration treatment is lower than the comprehensive cost required for water use by existing enterprises, bringing huge social and economic benefits to enterprises.

[0006] Its advantage is that the high-salt and high-COD membrane concentrate water after reverse osmosis membrane concentration can be reused for flushing multi-media filters, and the washing water is sent to the biochemical treatment pool for treatment. The disadvantage is that it is only suitable for membrane concentrate water that is easily biodegradable, or in scenarios where the proportion of recycled water reuse is small. For membrane concentrate water containing difficult-to-degrade organic matter, or a large proportion of recycled water reuse, the membrane concentrate water is sent to the biochemical system, and the difficult-to-degrade organic matter it contains is difficult to biodegrade, and it is enriched in the system, causing system imbalance; for scenarios where the proportion of recycled water reuse is large, the dilution effect of the biochemical unit water volume on the membrane concentrate water is reduced, and the effect of meeting the discharge standards after dilution cannot be achieved;

[0007] 3. The patent technology with announcement number CN104418423A discloses a method for catalytic ozone oxidation treatment of reverse osmosis concentrated water; peanut shell powder is impregnated with 60% phosphoric acid solution at a solid-liquid ratio of 1:1-1:3, the liquid is transferred to a crucible for activation, washed with 1% hydrochloric acid solution after cooling, washed with deionized water to pH=7, placed in an oven at 105°C to dry to constant weight, and sieved after grinding or ball milling; peanut shell activated carbon is impregnated in a transition metal ion solution with a mass concentration of 0.1-10% and a solid-liquid ratio of 1:1-1:10, dried, roasted, and ground; it is added to an ozone oxidation sewage treatment system containing reverse osmosis concentrated water, and the ozone oxidation sewage treatment temperature is 5-35°C; after the treatment is completed, the peanut shell activated carbon loaded with metal ion catalyst is separated and used for the next catalytic process; the catalyst of this method has rich pores, large specific surface area, and many surface active groups, and has strong adsorption and catalytic effects on organic pollutants in sewage.

[0008] The advantages of this method are that the powdered ozone catalyst is self-made and the catalyst is recycled, and the catalyst investment cost is low. The disadvantages are that the membrane concentrated water is treated by a single process of catalytic ozone oxidation, which has high operating costs and poor economic efficiency.

[0009] 4. The patent technology with announcement number CN102616995A discloses an ozone catalytic oxidation and biochemical composite treatment device for reverse osmosis concentrated water and its application method, including a fixed bed catalytic oxidation tower, an air aeration degassing tower, a fluidized bed biofilm reactor, a blower, an ozone generator, and a pipeline mixer; the reverse osmosis concentrated water storage tank is connected to the fixed bed catalytic oxidation tower through pipeline one, and a pipeline mixer is installed on pipeline one, and the pipeline mixer is connected to the ozone generator; the fixed bed catalytic oxidation tower is connected to the air aeration degassing tower through pipeline two, and the air aeration degassing tower is connected to the fluidized bed biofilm reactor through pipeline three, and the outlet of the fluidized bed biofilm reactor is connected to a secondary sedimentation tank; the fixed bed catalytic oxidation tower, the air aeration degassing tower and the fluidized bed biofilm reactor are all equipped with aeration pipes connected to the blower. The reverse osmosis concentrated water in this technology does not need to adjust the pH value; because the catalyst participates in the oxidation reaction, and the oxidation reaction is only controlled at the stage of destroying the molecular structure of organic pollutants, the ozone dosage is small, only about 40 mg / L is needed, and the treatment cost is low, about 0.6 yuan / m3 of sewage; this method has no secondary pollution and is green and environmentally friendly.

[0010] The advantages of this method are that it effectively combines the two processes of catalytic ozone oxidation and biochemical degradation, has low operating costs, no secondary pollution, and is green and environmentally friendly. The disadvantages are that it is suitable for application scenarios with relatively stable influent water quality, but it is difficult to meet the needs of large fluctuations in treatment load for applications with large fluctuations in water quality and water volume.

[0011] 5. Patent technology with announcement number CN200610157470.4 discloses a method and system for treating concentrated liquid of high-concentration wastewater through a reverse osmosis process, which involves the following methods: A. primary physical and chemical treatment of landfill leachate to produce pre-treated water; B. biological treatment and membrane separation of pre-treated water using a membrane bioreactor to produce reclaimed water; C. membrane treatment of reclaimed water using a membrane treatment system, and concentrated water is transported to an enhanced drying tank; D. the enhanced drying tank dries the concentrated water to produce solid matter. The system at least comprises a regulating tank, a reaction tank, a sedimentation tank and related pump equipment for primary physical and chemical treatment of landfill leachate. The produced pre-treated water is input into a membrane bioreactor; the membrane treatment system performs a filtration process on the reclaimed water output from the membrane bioreactor to produce concentrated water, which is output to an enhanced drying tank; the enhanced drying tank dries the concentrated water to produce air-dried solid matter. The technology will not cause secondary pollution to the environment and can achieve an effective and thorough pollution control effect.

[0012] In this method, the membrane concentrate water after water reuse is dried to produce solids, which can achieve effective and thorough pollution control. The disadvantage is that the drying energy consumption is high, and it is only suitable for the treatment of small and medium-sized membrane concentrate water; for membrane concentrate water with low solid content, the economic efficiency of the scheme is poor; for the treatment of large water volume, the equipment investment is huge.

[0013] In summary, the basic process of the existing RO concentrated water treatment process is to verify the feasibility of the scheme in a small test, and then determine the process scheme after optimizing the operating parameters. The treatment object is generally relatively fixed, and it is a fixed process for specific water quality and water quantity. Only when the quality and quantity of the inlet and outlet water fluctuate, the parameters are adjusted, and the process flow is basically unchangeable. In the production of enterprises, seasonal fluctuations in production load, equipment start-up and shutdown, abnormal production conditions, changes in production processes, etc., will cause large fluctuations in system drainage, pulse shocks, or large deviations between water quality and design conditions, requiring manual intervention to meet treatment requirements or upgrade the original process. If short-term water quality shocks cannot be handled in a timely and effective manner, it often leads to excessive effluent water quality or even system collapse. In general advanced oxidation deep treatment processes, the dosage of reagents is relatively fixed. After manual inspection and analysis of sampling and detection data, parameter fine-tuning is performed, and excessive reagents are generally added to ensure that the treatment meets the standards. It is not economically cost-effective to use dedicated personnel on duty for small water volume application scenarios. Summary of the invention

[0014] The present invention proposes a method for treating reverse osmosis concentrate, which is a membrane concentrate treatment scheme comprising three modules: "front-end catalytic ozone oxidation + aerated biological filter + back-end catalytic ozone oxidation". Among them, the front-end catalytic ozone oxidation plays a pre-oxidation role, performs a ring-opening and chain-breaking reaction on organic matter, and improves the biodegradability of the incoming water. The aerated biological filter biochemically degrades the organic matter after ring opening, removes COD and total nitrogen, ammonia nitrogen, and intercepts suspended solids in the wastewater. The back-end catalytic ozone oxidation is a synergistic oxidation, such as forming a multi-effect synergy with hydrogen peroxide to form per-ozone oxidation, enhance the treatment effect, and ensure that the effluent meets the standards.

[0015] The system of the present invention initially operates by using a three-module treatment process of "front-stage catalytic ozone oxidation + aerated biological filter + back-stage catalytic ozone oxidation". The automatic control system analyzes the inlet and outlet water quality indicators of the online detection instrument, selects the treatment module to be put into use, and optimizes and adjusts the dosage of the agent, the reflux ratio, etc.

[0016] The technical solution of the present invention is as follows: A method for treating reverse osmosis concentrated water, comprising the following process:

[0017] In the first step, the wastewater discharged from the RO concentrated water tank is treated in sequence through the first catalytic ozone oxidation module, the aerated biological filter module, the second catalytic ozone oxidation module, and the drainage return module;

[0018] In the second step, the online water quality detectors installed at the water inlet of the first catalytic ozone oxidation module, the aerated biological filter module, the second catalytic ozone oxidation module, and the drainage return module monitor the water quality indicators in real time, and transmit the detection data to the automatic control system;

[0019] In the third step, after the automatic control system performs system analysis and comparison, it uses the distribution controller to perform water intake, circuit breaking, or bypass operations on the first catalytic ozone oxidation module, the aerated biological filter module, the second catalytic ozone oxidation module, and the drainage return module.

[0020] Preferably, the first catalytic ozone oxidation module and the second catalytic ozone oxidation module each include a liquid oxygen storage tank, a vaporizer, an ozone generator, a centrifugal pump, a high-efficiency dosing device, and a catalytic ozone oxidation reaction tank, and the ozone generator and the centrifugal pump are both controlled to start and stop by the automatic control system;

[0021] The liquid oxygen in the liquid oxygen storage tank is vaporized by the vaporizer and then sent to the ozone generator. The formed ozone gas is mixed with the liquid in the catalytic ozone oxidation reaction tank pumped out by the centrifugal pump and enters the high-efficiency dosing device, and is recycled into the catalytic ozone oxidation reaction tank for catalytic ozone oxidation treatment.

[0022] Preferably, the aerated biological filter module comprises a dosing device, an aeration blower and an aerated biological filter, and both the dosing device and the aeration blower are controlled to start and stop by the automatic control system;

[0023] The dosing device puts biological bacteria agent for sewage treatment into the aerated biological filter, and fully contacts with the air delivered by the aeration blower, absorbs oxygen in the air, and then performs biological purification treatment on the sewage in the aerated biological filter.

[0024] Preferably, the drainage reflux module comprises a reflux pump and a discharge tank, and the reflux pump is used to pump the sewage in the discharge tank into the RO concentrate tank to achieve reflux at the water inlet of the reverse osmosis concentrate treatment system.

[0025] Preferably, the online water quality detector includes a first online analyzer, a second online analyzer, a third online analyzer and a fourth online analyzer. The first online analyzer is arranged on the pipeline from the RO concentrated water tank to the catalytic ozone oxidation reaction tank, and is used to detect the water quality to obtain the water inlet index N1. The second online analyzer is arranged on the pipeline from the catalytic ozone oxidation reaction tank to the aerated biological filter, and is used to detect the water quality to obtain the water inlet index N2. The third online analyzer is arranged on the pipeline from the aerated biological filter to the catalytic ozone oxidation reaction tank, and is used to detect the water quality to obtain the water inlet index N3. The fourth online analyzer is arranged on the pipeline from the catalytic ozone oxidation reaction tank to the discharge tank, and is used to detect the water quality to obtain the water inlet index N4. The water inlet indexes detected by the first online analyzer, the second online analyzer, the third online analyzer and the fourth online analyzer are all fed back to the automatic control system.

[0026] Preferably, the automatic control system includes a distribution controller V1, a distribution controller V2, a distribution controller V3 and a distribution controller V4, the distribution controller V1 is used to control the sewage discharge from the RO concentrated water tank to the catalytic ozone oxidation reaction tank according to the water inlet index N1 detected by the first online analyzer, the distribution controller V2 is used to control the sewage discharge from the catalytic ozone oxidation reaction tank to the aerated biological filter according to the water inlet index N2 detected by the second online analyzer, the distribution controller V3 is used to control the sewage discharge from the aerated biological filter to the catalytic ozone oxidation reaction tank according to the water inlet index N3 detected by the third online analyzer, and the distribution controller V4 is used to control the sewage backflow from the discharge tank to the RO concentrated water tank according to the water inlet index N4 detected by the fourth online analyzer.

[0027] Preferably, the first online analyzer is used to detect the water quality of the wastewater discharged from the RO concentrated water tank, and the water quality is fed back to the automatic control system to determine whether the detected water inlet index N1 is greater than the discharge standard M1;

[0028] When the water inlet index N1 is less than the discharge standard M1, step 1 is performed: the distribution controller V1, the distribution controller V2, the distribution controller V3 and the distribution controller V4 are turned on to discharge directly without passing through the catalytic ozone oxidation reaction tank, the aerated biological filter tank and the discharge tank;

[0029] When the water inlet index N1 is greater than the discharge standard M1, step 2 is executed: the automatic control system determines whether the water inlet index N1 is greater than the biodegradable index M2.

[0030] Preferably, when the water inlet index N1 is less than the biodegradable index M2 in step 2, the distribution controller V1 is turned off, the first catalytic ozone oxidation module is turned on to automatically run the program, the water inlet index N2 of the aerated biological filter module is detected by the second online detector, and the water inlet index N2 is fed back to the automatic control system to determine whether it is greater than the discharge standard M1;

[0031] When the water inlet index N2 is less than the discharge standard M1, step a is performed: the distribution controller V2, the distribution controller V3 and the distribution controller V4 are turned on to discharge the water directly without passing through the aerated biological filter tank and the catalytic ozone oxidation reaction tank;

[0032] When the water inlet index N2 is greater than the discharge standard M1, step b is executed: the automatic control system determines whether the water inlet index N2 is greater than the biodegradable index M2.

[0033] Preferably, when the water inlet index N2 is less than the biodegradable index M2 in step b, the distribution controller V2 is turned on, and step b1 is performed: the distribution controller V3 is turned off, the automatic control operation program of the second catalytic ozone oxidation module is turned on, the water inlet index N4 is detected by the fourth online analyzer, and the automatic control system is fed back to the automatic control system, and the automatic control system is used to determine whether the water inlet index N4 is greater than the emission standard M1;

[0034] When the water inlet index N4 is less than the discharge standard M1 in step b1, step b11 is executed: the distribution controller V4 is turned on to discharge directly;

[0035] When the water inlet index N4 is greater than the discharge standard M1 in step b1, step b12 is executed: the distribution controller V4 is closed, and the water flows back to the system water inlet RO concentrated water tank for further circulation treatment;

[0036] When the water inlet index N2 is greater than the biodegradable index M2 in step b, step b2 is performed: the distribution controller V2 is turned off, and the automatic control operation program of the aerated biological filter module is turned on, the water inlet index N3 is detected by the third online analyzer, and the automatic control system is fed back to the automatic control system, and the automatic control system is used to determine whether the water inlet index N3 is greater than the discharge standard M1;

[0037] When the water inlet index N3 is greater than the discharge standard M1, step b1 is executed;

[0038] When the water inlet index N3 is less than the discharge standard M1, step b21 is executed: the distribution controller V3 and the distribution controller V4 are turned on to discharge directly without passing through the catalytic ozone oxidation reaction tank.

[0039] Preferably, when the water inlet index N1 is greater than the biodegradable index M2 in step 2, the distribution controller V1 is turned on and step b2 is started.

[0040] The beneficial effects of the present invention are:

[0041] 1. Since the water quality of the double membrane method is often unstable and susceptible to production abnormalities, the treatment process of membrane concentrated water should adopt a technical process that can better adapt to changes in sewage quality and has a strong ability to resist impact loads, while considering meeting the disposal standards. The present invention adopts online water quality index detection to avoid the lag of offline detection, can be unattended, self-controlled operation, and has great process operation flexibility. It is suitable for application scenarios with huge fluctuations in incoming water quality. The selected process module parameters are simple to adjust and easy to switch;

[0042] 2. The present invention adopts online water quality monitoring, and can select a treatment plan (full process or partial process operation) according to needs, and adjust the dosage of the reagent (the number of stages of multi-stage aeration, the aeration volume, and the amount of emergency hydrogen peroxide added). BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0044] Figure 1 A flow chart of a method for treating reverse osmosis concentrated water proposed by the present invention;

[0045] Figure 2 This is a schematic diagram of the catalytic ozone oxidation module proposed in the present invention;

[0046] Figure 3 This is a schematic diagram of the aerated biological filter module proposed by the present invention;

[0047] Figure 4 This is a schematic diagram of the drainage return module proposed by the present invention;

[0048] Figure 5 It is a logic diagram of the automatic control operation during the reverse osmosis concentrated water treatment of the present invention. DETAILED DESCRIPTION

[0049] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] See also Figure 1 The present invention provides a method for treating reverse osmosis concentrated water, comprising the following steps:

[0051] In the first step, the wastewater discharged from the RO concentrated water tank is treated in sequence through the first catalytic ozone oxidation module, the aerated biological filter module, the second catalytic ozone oxidation module, and the drainage return module;

[0052] In the second step, the online water quality detectors installed at the water inlet of the first catalytic ozone oxidation module, the aerated biological filter module, the second catalytic ozone oxidation module, and the drainage return module monitor the water quality indicators in real time, and transmit the detection data to the automatic control system;

[0053] In the third step, after the automatic control system performs system analysis and comparison, it uses the distribution controller to perform water intake, circuit breaking, or bypass operations on the first catalytic ozone oxidation module, the aerated biological filter module, the second catalytic ozone oxidation module, and the drainage return module.

[0054] See also Figure 2The first catalytic ozone oxidation module and the second catalytic ozone oxidation module both include a liquid oxygen storage tank, a vaporizer, an ozone generator, a centrifugal pump, a high-efficiency dosing device, and a catalytic ozone oxidation reaction pool. The ozone generator and the centrifugal pump are both started and stopped by an automatic control system. The liquid oxygen in the liquid oxygen storage tank is vaporized by the vaporizer and then sent to the ozone generator. The formed ozone gas is mixed with the liquid in the catalytic ozone oxidation reaction pool pumped out by the centrifugal pump and enters the high-efficiency dosing device, and is recycled into the catalytic ozone oxidation reaction pool for catalytic ozone oxidation treatment.

[0055] See also Figure 3 The aerated biological filter module includes a dosing device, an aeration blower and an aerated biological filter. The dosing device and the aeration blower are both started and stopped by the automatic control system. The dosing device puts biological bacteria agents for sewage treatment into the aerated biological filter, and fully contacts with the air delivered by the aeration blower, absorbs oxygen in the air, and then biologically purifies the sewage in the aerated biological filter.

[0056] See also Figure 4 The drainage return module includes a return pump and a discharge tank. The return pump is used to pump the sewage in the discharge tank into the RO concentrated water tank to achieve the return of the water inlet of the reverse osmosis concentrated water treatment system.

[0057] It should be noted that the above-mentioned online water quality detector includes a first online analyzer, a second online analyzer, a third online analyzer and a fourth online analyzer. The first online analyzer is arranged on the pipeline from the RO concentrated water tank to the catalytic ozone oxidation reaction tank, and is used to detect the water quality to obtain the water inlet index N1. The second online analyzer is arranged on the pipeline from the catalytic ozone oxidation reaction tank to the aerated biological filter, and is used to detect the water quality to obtain the water inlet index N2. The third online analyzer is arranged on the pipeline from the aerated biological filter to the catalytic ozone oxidation emission tank, and is used to detect the water quality to obtain the water inlet index N3. The fourth online analyzer is arranged on the pipeline from the catalytic ozone oxidation reaction tank to the emission tank, and is used to detect the water quality to obtain the water inlet index N4. The water inlet indexes detected by the first online analyzer, the second online analyzer, the third online analyzer and the fourth online analyzer are all fed back to the automatic control system.

[0058] It should be noted that the above-mentioned automatic control system includes a distribution controller V1, a distribution controller V2, a distribution controller V3 and a distribution controller V4. The distribution controller V1 is used to control the sewage discharge from the RO concentrated water tank to the catalytic ozone oxidation reaction tank according to the water inlet index N1 detected by the first online analyzer. The distribution controller V2 is used to control the sewage discharge from the catalytic ozone oxidation reaction tank to the aerated biological filter according to the water inlet index N2 detected by the second online analyzer. The distribution controller V3 is used to control the sewage discharge from the aerated biological filter to the catalytic ozone oxidation reaction tank according to the water inlet index N3 detected by the third online analyzer. The distribution controller V4 is used to control the sewage backflow from the discharge tank to the RO concentrated water tank according to the water inlet index N4 detected by the fourth online analyzer.

[0059] Comparative Example

[0060] The traditional process that cannot be automatically adjusted was used to treat the fluctuation of feed water quality as a comparative example, that is, a membrane concentrate water treatment solution including three modules of "catalytic ozone oxidation reaction tank 1 + aerated biological filter + catalytic ozone oxidation emission tank 2" was selected to carry out RO concentrate water treatment, and the effluent was not returned.

[0061] The experimental device is designed to handle water volume of 1m 3 / h. The catalyst of catalytic ozone oxidation reaction pool 1 is a certain commercial aluminum-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 100mg / L, and the hydraulic retention time is 30min; the aerated biological filter is inoculated with the activated sludge from the secondary sedimentation tank of the paper mill, the empty tower hydraulic load is 1m / h, and the volumetric load is 0.3kg BOD / m 3 ·d, hydraulic retention time 2h; the catalyst of catalytic ozone oxidation emission pool 2 is a certain commercial model of activated carbon-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 150mg / L, and the hydraulic retention time is 30min. The influent water quality indicators are COD 230-260mg / L, BOD15-25 mg / L. After stable operation, the system effluent COD is 85-170mg / L.

[0062] The basic process of the existing RO concentrated water treatment process is to verify the feasibility of the scheme in a small test, and then determine the process scheme after optimizing the operating parameters. The treatment object is generally relatively fixed, and it is a fixed process for specific water quality and water quantity. Only when the quality and quantity of the inlet and outlet water fluctuate, the parameters are adjusted, and the process flow is basically unchangeable. In the production of enterprises, seasonal fluctuations in production load, equipment start-up and shutdown, abnormal production conditions, changes in production processes, etc., will cause large fluctuations in system drainage, pulse shocks, or large deviations between the water quality and the design situation, requiring manual intervention to meet the treatment requirements or upgrade the original process. If short-term water quality shocks cannot be handled in a timely and effective manner, it often leads to excessive effluent water quality or even system collapse. In general advanced oxidation deep treatment processes, the dosage of reagents is relatively fixed, and the parameters are fine-tuned after manual inspection and analysis of sampling and detection data. Generally, excessive reagents are added to ensure that the treatment meets the standards. Using a dedicated person on duty cannot respond to abnormal conditions in a timely and accurate manner, and it is not economically cost-effective for small water volume application scenarios. The following is an explanation of a case in actual application of a method for treating reverse osmosis concentrated water proposed in the present invention:

[0063] Example 1: The present invention is applied to the double membrane concentrated water of the water reuse system in a domestic papermaking enterprise industrial wastewater regeneration water utilization project for pilot experiments. The RO concentrated water indicators of the system are: COD 150-350 mg / L, BOD 10-30 mg / L, chromaticity 50 times, total nitrogen 30-50 mg / L, alkalinity (calculated as calcium carbonate) 1100-1300 mg / L, chloride 1000-1200 mg / L, calcium ion 600-900 mg / L, magnesium ion 30-70 mg / L.

[0064] A membrane concentrate treatment solution consisting of three modules, "catalytic ozone oxidation reaction tank 1 + aerated biological filter + catalytic ozone oxidation emission tank 2", is selected for RO concentrate treatment, and the effluent does not flow back. After the system runs stably, switch to automatic operation mode. Among them, the front-end catalytic ozone oxidation plays a pre-oxidation role, performs a ring-opening and chain-breaking reaction on organic matter, and improves the biodegradability of the incoming water. The aerated biological filter biodegrades the organic matter after the ring is opened, removes COD and total nitrogen, ammonia nitrogen, and intercepts suspended solids in the wastewater. The back-end catalytic ozone oxidation is a synergistic oxidation, such as forming a multi-effect synergy of per-ozone oxidation with hydrogen peroxide, which can enhance the treatment effect and ensure that the effluent meets the standards.

[0065] The experimental device is designed to process 1m3 / h of water. The catalyst in the catalytic ozone oxidation reaction pool 1 is a certain commercial aluminum-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 100mg / L, the automatic control system sets the ozone addition concentration to 30% of the influent COD, and the hydraulic retention time is 30min; the aerated biological filter uses the activated sludge from the secondary sedimentation tank of the paper mill to inoculate, the empty tower hydraulic load is 1m / h, and the volumetric load is 0.3kg BOD / m 3d, hydraulic retention time 2h; the catalyst of catalytic ozone oxidation emission pool 2 is a certain commercial model of activated carbon-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 150mg / L, the automatic control system sets the ozone addition concentration to 50% of the influent COD, and the hydraulic retention time is 30min. The influent water quality index COD 230-260mg / L, BOD15-25 mg / L. Set the effluent index M1: COD<100mg / L, biodegradable index M2: BOD / COD≥0.3. After the system is switched to automatic operation, it will run continuously for 7 days, and the actual operation module is "catalytic ozone oxidation reaction pool 1 + catalytic ozone oxidation emission pool 2". The system effluent COD is 90-100mg / L.

[0066] Example 2

[0067] Add appropriate amount of glucose to the RO concentrated water tank, adjust the water inlet index to: COD 300-340mg / L, BOD 90-110mg / L, select the membrane concentrated water treatment scheme including "catalytic ozone oxidation reaction tank 1 + aerated biological filter + catalytic ozone oxidation emission tank 2" three modules for RO concentrated water treatment, and the effluent does not flow back. After the system runs stably, switch to automatic operation mode.

[0068] The catalyst of catalytic ozone oxidation reaction pool 1 is a certain commercial aluminum-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 100 mg / L, the automatic control system sets the ozone addition concentration to 30% of the influent COD, and the hydraulic retention time is 30 minutes; the aerated biological filter uses the activated sludge from the secondary sedimentation tank of the paper mill to inoculate, the empty tower hydraulic load is 1m / h, and the volumetric load is 0.3kg BOD / m 3 d, hydraulic retention time 2h; the catalyst of catalytic ozone oxidation emission pool 2 is a certain commercial model of activated carbon-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 200mg / L, the automatic control system sets the ozone addition concentration to 50% of the influent COD, and the hydraulic retention time is 30min. Set the effluent index M1: COD<100mg / L, and the biodegradable index M2: BOD / COD≥0.3. After the system is switched to automatic operation, it will run continuously for 7 days, and the operation module is "catalytic ozone oxidation reaction 1+aerated biological filter+catalytic ozone oxidation emission pool 2". The system effluent COD is 90-100mg / L.

[0069] Example 3

[0070] Adjust the inlet water index to: COD 230-260 mg / L, BOD15-25 mg / L, select the membrane concentrate water treatment solution including "catalytic ozone oxidation reaction tank 1 + aerated biological filter + catalytic ozone oxidation emission tank 2" three modules for RO concentrate water treatment, and the effluent will not flow back. After the system runs stably, switch to automatic operation mode.

[0071] Set the effluent index M1: COD < 500 mg / L, and the biodegradable index M2: BOD / COD ≥ 0.3. After the system switches to automatic operation, no module is put into operation, and the system effluent COD is 230-260 mg / L.

[0072] Example 4

[0073] Glucose solution was prepared in the RO concentrated water tank, and the inlet water index was adjusted to: COD 130-150mg / L, BOD 130-150mg / L. The membrane concentrated water treatment scheme including "catalytic ozone oxidation reaction tank 1 + aerated biological filter + catalytic ozone oxidation emission tank 2" was selected for RO concentrated water treatment, and the effluent was not refluxed. After the system runs stably, switch to automatic operation mode.

[0074] The catalyst of catalytic ozone oxidation reaction pool 1 is a certain commercial aluminum-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 100 mg / L, the automatic control system sets the ozone addition concentration to 30% of the influent COD, and the hydraulic retention time is 30 minutes; the aerated biological filter uses the activated sludge from the secondary sedimentation tank of the paper mill to inoculate, the empty tower hydraulic load is 1m / h, and the volumetric load is 0.3kg BOD / m 3 d, hydraulic retention time 2h; the catalyst of catalytic ozone oxidation emission pool 2 is a certain commercial model of activated carbon-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 200mg / L, the automatic control system sets the ozone addition concentration to 50% of the influent COD, and the hydraulic retention time is 30min. Set the effluent index M1: COD<100mg / L, the biodegradable index M2: BOD / COD≥0.3. After the system is switched to automatic operation, it will run continuously for 7 days, and the operation module is "aerated biological filter". The system effluent COD is 30-50mg / L.

[0075] Example 5

[0076] Add pure water and glucose to the RO concentrated water tank, adjust the water inlet index to: COD 150 ~ 180mg / L, BOD 60 ~ 90mg / L, select the membrane concentrated water treatment solution including "catalytic ozone oxidation reaction tank 1 + aerated biological filter + catalytic ozone oxidation emission tank 2" three modules for RO concentrated water treatment, and the effluent does not flow back. After the system runs stably, switch to automatic operation mode.

[0077] The catalyst of catalytic ozone oxidation reaction pool 1 is a certain commercial aluminum-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 100 mg / L, the automatic control system sets the ozone addition concentration to 30% of the influent COD, and the hydraulic retention time is 30 minutes; the aerated biological filter uses the activated sludge from the secondary sedimentation tank of the paper mill to inoculate, the empty tower hydraulic load is 1m / h, and the volumetric load is 0.3kg BOD / m 3 d, hydraulic retention time 2h; the catalyst of catalytic ozone oxidation emission pool 2 is a certain commercial model of activated carbon-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 200mg / L, the automatic control system sets the ozone addition concentration to 50% of the influent COD, and the hydraulic retention time is 30min. Set the effluent index M1: COD<100mg / L, the biodegradable index M2: BOD / COD≥0.3. After the system is switched to automatic operation, it will run continuously for 7 days, and the operation module is "aerated biological filter + catalytic ozone oxidation emission pool 2". The system effluent COD is 60-80mg / L.

[0078] Example 6

[0079] Every 48 hours, pure water and glucose are added to the membrane concentrate water in the RO concentrate tank with the original water quality indicators of COD 230-260 mg / L and BOD15-25 mg / L, and the inlet water indicators are adjusted to: COD 160-180 mg / L, BOD 55-70 mg / L to simulate the scenario of feed pulse fluctuation. The membrane concentrate water treatment scheme including "catalytic ozone oxidation reaction tank 1 + aerated biological filter + catalytic ozone oxidation emission tank 2" three modules is selected for RO concentrate water treatment, and the effluent does not flow back. After the system runs stably, switch to automatic operation mode.

[0080] The catalyst of catalytic ozone oxidation reaction pool 1 is a certain commercial aluminum-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 100 mg / L, the automatic control system sets the ozone addition concentration to 30% of the influent COD, and the hydraulic retention time is 30 minutes; the aerated biological filter uses the activated sludge from the secondary sedimentation tank of the paper mill to inoculate, the empty tower hydraulic load is 1m / h, and the volumetric load is 0.3kg BOD / m 3 d, hydraulic retention time 2h; the catalyst of catalytic ozone oxidation emission pool 2 is a certain commercial model of activated carbon-based catalyst, the catalyst filling height is 2 meters, the initial ozone addition concentration is 200mg / L, the automatic control system sets the ozone addition concentration to 50% of the influent COD, and the hydraulic retention time is 30min. Set the effluent index M1: COD<100mg / L, and the biodegradable index M2: BOD / COD≥0.3. After the system is switched to automatic operation and runs continuously for 7 days, the system effluent COD is 85-100mg / L.

[0081] The above examples verify the membrane concentrate water treatment scheme of the present invention through the three modules of "catalytic ozone oxidation reaction tank + aerated biological filter + catalytic ozone oxidation emission tank". Among them, the front-end catalytic ozone oxidation can play a pre-oxidation role, open the ring and break the chain reaction of organic matter, and improve the biodegradability of the incoming water. The aerated biological filter can biochemically degrade the organic matter after opening the ring, remove COD and total nitrogen, ammonia nitrogen, and intercept suspended solids in the wastewater. The back-end catalytic ozone oxidation can synergistically oxidize, such as forming a multi-effect synergy of per-ozone oxidation with hydrogen peroxide, enhancing the treatment effect and ensuring that the effluent meets the standards.

[0082] The system is initially operated using a three-module treatment process of "catalytic ozone oxidation reaction tank + aerated biological filter + catalytic ozone oxidation emission tank". The automatic control system analyzes the inlet and outlet water quality indicators of the online detection instrument, selects the treatment module to be put into use, and optimizes and adjusts the dosage of the reagent, reflux ratio, etc. to improve the treatment efficiency of RO concentrated water.

[0083] Please attach Figure 5 The working principle and use process of the present invention are as follows:

[0084] The first online analyzer is used to test the water quality of the wastewater discharged from the RO concentrated water tank, and the water quality is fed back to the automatic control system to determine whether the water inlet index N1 is greater than the discharge standard M1;

[0085] When the water inlet index N1 is less than the discharge standard M1, step 1 is executed: the distribution controller V1, the distribution controller V2, the distribution controller V3 and the distribution controller V4 are turned on, and the water is directly discharged without passing through the catalytic ozone oxidation reaction tank, the aerated biological filter tank and the catalytic ozone oxidation reaction tank;

[0086] When the water inlet index N1 is greater than the discharge standard M1, step 2 is executed: the automatic control system determines whether the water inlet index N1 is greater than the biodegradable index M2.

[0087] When the water inlet index N1 is less than the biodegradable index M2 in step 2, the distribution controller V1 is turned off, the first catalytic ozone oxidation module is turned on to automatically run the program, the water inlet index N2 of the aerated biological filter module is detected by the second online detector, and the water inlet index N2 is fed back to the automatic control system to determine whether it is greater than the discharge standard M1;

[0088] When the water inlet index N2 is less than the discharge standard M1, step a is executed: the distribution controller V2, the distribution controller V3 and the distribution controller V4 are turned on, and the water is discharged directly without passing through the aerated biological filter tank and the catalytic ozone oxidation discharge tank;

[0089] When the water inlet index N2 is greater than the discharge standard M1, step b is executed: the automatic control system determines whether the water inlet index N2 is greater than the biodegradable index M2.

[0090] When the water inlet index N2 is less than the biodegradable index M2 in step b, the distribution controller V2 is turned on, and step b1 is executed: the distribution controller V3 is turned off, and the automatic control operation program of the second catalytic ozone oxidation module is turned on, and the water inlet index N4 is detected by the fourth online analyzer, and fed back to the automatic control system, and the automatic control system is used to determine whether the water inlet index N4 is greater than the emission standard M1;

[0091] When the water inlet index N4 is less than the discharge standard M1 in step b1, step b11 is executed: the distribution controller V4 is turned on to discharge directly;

[0092] When the water inlet index N4 is greater than the discharge standard M1 in step b1, step b12 is executed: the distribution controller V4 is closed and the water is returned to the system water inlet RO concentrated water tank for further circulation;

[0093] When the water inlet index N2 is greater than the biodegradable index M2 in step b, step b2 is executed: the distribution controller V2 is turned off, and the automatic control operation program of the aerated biological filter module is turned on, the water inlet index N3 is detected by the third online analyzer, and the feedback is fed back to the automatic control system, and the automatic control system is used to determine whether the water inlet index N3 is greater than the discharge standard M1;

[0094] When the water inlet index N3 is greater than the discharge standard M1, step b1 is executed;

[0095] When the water inlet index N3 is less than the discharge standard M1, step b21 is executed: the distribution controller V3 and the distribution controller V4 are turned on to discharge directly without passing through the catalytic ozone oxidation discharge tank.

[0096] When the water inlet index N1 is greater than the biodegradable index M2 in step 2, the distribution controller V1 is turned on and step b2 is started.

[0097] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for treating reverse osmosis concentrated water, characterized in that: The process includes: In the first step, the wastewater discharged from the RO concentrated water tank is treated in sequence through the first catalytic ozone oxidation module, the aerated biological filter module, the second catalytic ozone oxidation module, and the drainage return module; In the second step, the online water quality detectors installed at the water inlet of the first catalytic ozone oxidation module, the aerated biological filter module, the second catalytic ozone oxidation module, and the drainage return module monitor the water quality indicators in real time, and transmit the detection data to the automatic control system; In the third step, after the automatic control system performs system analysis and comparison, it uses the distribution controller to perform water intake, circuit breaking, or bypass operations on the first catalytic ozone oxidation module, the aerated biological filter module, the second catalytic ozone oxidation module, and the drainage return module.

2. The method for treating reverse osmosis concentrated water according to claim 1, characterized in that: The first catalytic ozone oxidation module and the second catalytic ozone oxidation module each include a liquid oxygen storage tank, a vaporizer, an ozone generator, a centrifugal pump, a high-efficiency dosing device, and a catalytic ozone oxidation reaction tank, and the ozone generator and the centrifugal pump are both controlled by the automatic control system to start, stop and adjust; The liquid oxygen in the liquid oxygen storage tank is vaporized by the vaporizer and then sent to the ozone generator. The formed ozone gas is mixed with the liquid in the catalytic ozone oxidation reaction tank pumped out by the centrifugal pump and enters the high-efficiency dosing device, and is recycled into the catalytic ozone oxidation reaction tank for catalytic ozone oxidation treatment.

3. The method for treating reverse osmosis concentrated water according to claim 2, characterized in that: The aerated biological filter module includes a dosing device, an aeration blower and an aerated biological filter, and the dosing device and the aeration blower are both controlled by the automatic control system to start and stop and flow control; The dosing device puts biological bacteria agent for sewage treatment into the aerated biological filter, and fully contacts with the air delivered by the aeration blower, absorbs oxygen in the air, and then performs biological purification treatment on the sewage in the aerated biological filter.

4. The method for treating reverse osmosis concentrated water according to claim 3, characterized in that: The drainage reflux module includes a reflux pump and a discharge tank. The reflux pump is used to pump the sewage in the discharge tank into the RO concentrated water tank to achieve reflux at the water inlet of the reverse osmosis concentrated water treatment system.

5. The method for treating reverse osmosis concentrated water according to claim 4, characterized in that: The online water quality detector includes a first online analyzer, a second online analyzer, a third online analyzer and a fourth online analyzer. The first online analyzer is arranged on the pipeline from the RO concentrated water tank to the catalytic ozone oxidation reaction tank, and is used to detect the water quality to obtain the water inlet index N1. The second online analyzer is arranged on the pipeline from the catalytic ozone oxidation reaction tank to the aerated biological filter, and is used to detect the water quality to obtain the water inlet index N2. The third online analyzer is arranged on the pipeline from the aerated biological filter to the catalytic ozone oxidation reaction tank, and is used to detect the water quality to obtain the water inlet index N3. The fourth online analyzer is arranged on the pipeline from the catalytic ozone oxidation reaction tank to the discharge tank, and is used to detect the water quality to obtain the water inlet index N4. The water inlet indexes detected by the first online analyzer, the second online analyzer, the third online analyzer and the fourth online analyzer are all fed back to the automatic control system.

6. The method for treating reverse osmosis concentrated water according to claim 5, characterized in that: The automatic control system includes a distribution controller V1, a distribution controller V2, a distribution controller V3 and a distribution controller V4. The distribution controller V1 is used to control the sewage discharge from the RO concentrated water tank to the catalytic ozone oxidation reaction tank according to the water inlet index N1 detected by the first online analyzer. The distribution controller V2 is used to control the sewage discharge from the catalytic ozone oxidation reaction tank to the aerated biological filter according to the water inlet index N2 detected by the second online analyzer. The distribution controller V3 is used to control the sewage discharge from the aerated biological filter to the catalytic ozone oxidation reaction tank according to the water inlet index N3 detected by the third online analyzer. The distribution controller V4 is used to control the sewage backflow from the discharge tank to the RO concentrated water tank according to the water inlet index N4 detected by the fourth online analyzer.

7. A method for treating reverse osmosis concentrated water according to claim 6, characterized in that: The first online analyzer is used to detect the water quality of the wastewater discharged from the RO concentrated water tank, and the result is fed back to the automatic control system to determine whether the detected water inlet index N1 is greater than the discharge standard M1; When the water inlet index N1 is less than the discharge standard M1, step 1 is performed: the distribution controller V1, the distribution controller V2, the distribution controller V3 and the distribution controller V4 are turned on to discharge directly without passing through the catalytic ozone oxidation reaction tank and the aerated biological filter tank; When the water inlet index N1 is greater than the discharge standard M1, step 2 is executed: the automatic control system determines whether the water inlet index N1 is greater than the biodegradable index M2.

8. The method for treating reverse osmosis concentrated water according to claim 7, characterized in that: When the water inlet index N1 is less than the biodegradable index M2 in step 2, the distribution controller V1 is turned off, the first catalytic ozone oxidation module is turned on to automatically run the program, the water inlet index N2 of the aerated biological filter module is detected by the second online detector, and the water inlet index N2 is fed back to the automatic control system to determine whether it is greater than the discharge standard M1; When the water inlet index N2 is less than the discharge standard M1, step a is performed: the distribution controller V2, the distribution controller V3 and the distribution controller V4 are turned on to discharge the water directly without passing through the aerated biological filter tank and the catalytic ozone oxidation reaction tank; When the water inlet index N2 is greater than the discharge standard M1, step b is executed: the automatic control system determines whether the water inlet index N2 is greater than the biodegradable index M2.

9. The method for treating reverse osmosis concentrated water according to claim 8, characterized in that: When the water inlet index N2 is less than the biodegradable index M2 in step b, the distribution controller V2 is turned on, and step b1 is performed: the distribution controller V3 is turned off, the automatic control operation program of the second catalytic ozone oxidation module is turned on, the water inlet index N4 is detected by the fourth online analyzer, and the automatic control system is used to determine whether the water inlet index N4 is greater than the emission standard M1; When the water inlet index N4 is less than the discharge standard M1 in step b1, step b11 is executed: the distribution controller V4 is turned on to discharge directly; When the water inlet index N4 is greater than the discharge standard M1 in step b1, step b12 is executed: the distribution controller V4 is closed, and the water flows back to the system water inlet RO concentrated water tank for further circulation treatment; When the water inlet index N2 is greater than the biodegradable index M2 in step b, step b2 is performed: the distribution controller V2 is turned off, and the automatic control operation program of the aerated biological filter module is turned on, the water inlet index N3 is detected by the third online analyzer, and the automatic control system is fed back to the automatic control system, and the automatic control system is used to determine whether the water inlet index N3 is greater than the discharge standard M1; When the water inlet index N3 is greater than the discharge standard M1, step b1 is executed; When the water inlet index N3 is less than the discharge standard M1, step b21 is executed: the distribution controller V3 and the distribution controller V4 are turned on to discharge directly without passing through the catalytic ozone oxidation reaction tank.

10. The method for treating reverse osmosis concentrated water according to claim 9, characterized in that: When the water inlet index N1 is greater than the biodegradable index M2 in step 2, the distribution controller V1 is turned on and step b2 is started.

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