An integrated device and method for advanced treatment of sewage by coupling high-level oxidation with reverse osmosis membrane

Abstract

This invention discloses an integrated device for deep wastewater treatment using advanced oxidation coupled reverse osmosis membrane technology. This device, by incorporating an electro-oxidation tank, an ozone oxidation tank, and a reverse osmosis membrane tank, achieves excellent removal of ammonia nitrogen, chloride ions, and organic matter without the need for additional reagents, effectively avoiding secondary pollution. It boasts high removal rates, stable operation, and convenient management and maintenance, offering significant economic and environmental advantages. This invention also discloses a method for treating wastewater using the aforementioned device.

Description

Technical Field

[0001] This invention belongs to the field of wastewater recycling technology, specifically relating to an integrated device and method for deep treatment of wastewater using advanced oxidation coupled reverse osmosis membrane technology. Background Technology

[0002] In recent years, due to rapid socio-economic development and the continuous improvement of residents' living standards, human activities require more and more freshwater resources, resulting in a large amount of sewage discharge. Therefore, reclaimed water reuse has become one of the important ways to solve water shortages. In 1958, my country began to include urban sewage treatment and utilization in its scientific research projects. In 1985, my country's first truly meaningful reclaimed water reuse project was completed at the Beijing Environmental Science Research Institute, with a treatment capacity of 120 m³ / d. In 1992, my country's first urban reclaimed water reuse project for industrial use was completed in Dalian. In 2002, three standards were issued: "Water Quality Standards for Urban Sewage Reuse for Miscellaneous Uses," "Water Quality Standards for Urban Sewage Reuse for Landscape and Environmental Uses," and "Standards for Irrigation Water Quality," which greatly promoted the upgrading and transformation of urban sewage treatment plants towards reclaimed water reuse.

[0003] Reclaimed water is an important component of water resources and one of the most widely used types of water resources. The source of reclaimed water should not only utilize wastewater as a potential water source, but also make full use of the substances contained in the wastewater itself to maximize the comprehensive benefits of wastewater resource utilization.

[0004] Reverse osmosis (RO) is a process that uses the pressure difference across a semi-permeable membrane as the driving force to selectively allow the solvent to permeate through the membrane, thus achieving solvent-solute separation. Its membrane pore size reaches the nanometer scale, and the polymer materials used exhibit excellent repulsion for salts, while retaining dissolved organic matter and high-valence ions (such as calcium carbonate) in water. 2+ Mg 2+ (etc.) and low-valence ions (such as Na+, etc.) + K + (etc.) It has a good removal effect. It has the characteristics of not involving phase change, low energy consumption, and good effluent quality. Because the reverse osmosis operation pressure is relatively low, it can remove dissolved organic matter and inorganic ions in water while retaining some trace elements in the water. Its excellent purification effect can reduce the environmental and health risks of reclaimed water.

[0005] However, the treatment of concentrate and the control of membrane fouling have become persistent concerns. The concentrate contains high concentrations of various ions and organic matter, and direct discharge would cause environmental pollution. The accumulation of contaminants on the membrane leads to lower membrane flux, severely impacting the membrane's water purification efficiency and resulting in significant economic waste. Summary of the Invention

[0006] The purpose of this invention is to provide an integrated device for deep treatment of wastewater using advanced oxidation-coupled reverse osmosis membrane technology, in order to overcome the shortcomings of existing technologies.

[0007] Another objective of this invention is to provide a method for continuously treating wastewater using the aforementioned apparatus.

[0008] The first objective of this invention can be achieved through the following technical solution: an integrated device for deep treatment of wastewater using advanced oxidation-coupled reverse osmosis membrane technology, comprising:

[0009] Water storage tank, electro-oxidation tank, power supply, ozone oxidation tank, ozone generator, first buffer tank, second buffer tank, reverse osmosis membrane tank, greywater reuse tank and automatic control mechanism;

[0010] The water storage tank has four outlets, wherein the first outlet and the third outlet are respectively connected to the inlet of the reverse osmosis membrane tank through pipes, the second outlet is connected to the first inlet of the electro-oxidation tank through a pipe, and the fourth outlet is connected to the first inlet of the ozone oxidation tank through a pipe.

[0011] The pipeline connecting the water storage tank and the reverse osmosis membrane tank is equipped with a control valve, a flow meter and a booster pump; the pipeline connecting the water storage tank and the electro-oxidation tank or the ozone oxidation tank is equipped with a control valve and a flow meter.

[0012] The electro-oxidation cell is powered by a power source, and the outlet of the electro-oxidation cell is connected to the inlet of the first buffer cell via a pipe.

[0013] The ozone oxidation tank is supplied with ozone by the ozone generator, and the outlet end of the ozone oxidation tank is connected to the inlet end of the second buffer tank through a pipeline.

[0014] A gas flow meter is installed on the pipe connecting the ozone oxidation tank and the ozone generator;

[0015] The outlet ends of the first buffer tank and the second buffer tank are connected to the inlet end of the reverse osmosis membrane tank through pipes;

[0016] The reverse osmosis membrane tank has two outlet ends. One outlet end is connected to the inlet end of the wastewater reuse tank through a pipe, and the other outlet end is connected to the ozone oxidation tank or the second inlet end of the oxidation tank through a pipe, for returning the concentrate in the reverse osmosis membrane tank to the ozone oxidation tank or the electro-oxidation tank.

[0017] The pipeline connecting the reverse osmosis membrane tank to the ozone oxidation tank or the electro-oxidation tank is equipped with a control valve, a flow meter and a booster pump;

[0018] The control valve, flow meter, booster pump, and gas flow meter are all connected to and controlled by the automatic control mechanism.

[0019] Optionally, a control valve is provided on the pipe connecting the electro-oxidation tank to the first buffer tank, a control valve is provided on the pipe connecting the ozone oxidation tank to the second buffer tank, a control valve and a booster pump are provided on the pipe connecting the first buffer tank or the second buffer tank to the reverse osmosis membrane tank, and a control valve and a flow meter are provided on the pipe connecting the reverse osmosis membrane tank to the greywater reuse tank.

[0020] Optionally, the electro-oxidation cell includes an electro-oxidation cell perforated partition, an anode, and a cathode, wherein the anode is connected to the positive terminal of the power supply, and the cathode is connected to the negative terminal of the power supply.

[0021] Optionally, the ozone oxidation tank includes a baffle plate and a perforated baffle plate for the ozone oxidation tank, and a catalyst placement area is provided between the baffle plate and the perforated baffle plate for the ozone oxidation tank.

[0022] Optionally, the catalyst includes, but is not limited to, manganese dioxide.

[0023] Optionally, the ozone generator is supplied with a pure oxygen generator, and an exhaust gas collection pipe is provided above the tail end of the ozone generating pool.

[0024] Optionally, the reverse osmosis membrane tank includes a membrane module, with a membrane tank inlet pipe below the membrane module connected to the water storage tank, the first buffer tank, or the second buffer tank, and a concentrate return pipe above the membrane module connected to the electro-oxidation tank or the ozone oxidation tank. The concentrate return pipe is equipped with a drain valve, and a membrane tank outlet pipe above the membrane module is connected to the greywater reuse tank.

[0025] In the event of excessive concentrate volume during operation, the drain valve can discharge the excess reverse osmosis concentrate when the initial concentrate volume reaches the specified level.

[0026] Optionally, the reverse osmosis membrane used in the membrane module is an organic membrane and cannot be an aromatic polyamide membrane.

[0027] In the initial stage of operation, the wastewater in the storage tank needs to be concentrated by reverse osmosis. The flow rate of the concentrate is controlled by the concentrate return control valve and the flow meter.

[0028] The selection of the advanced oxidation tank is controlled by the concentration of ammonia nitrogen, chloride ion, organic matter and influent volume in the water. When the influent volume is large or the pollutant concentration is high, the ozone oxidation tank is selected. After the system has been running for several cycles, some sewage (raw water) can be added back from the storage tank to adjust the concentrate so that it matches the treatment capacity of the electro-oxidation tank and achieves the cleaning effect on the membrane.

[0029] Therefore, a flow meter and a control valve are installed between the water storage tank and the electro-oxidation tank or the ozone oxidation tank. When the concentrate is returned, the flow meter and control valve control the wastewater in the water storage tank to enter the electro-oxidation tank or the ozone oxidation tank and mix it with the concentrate in a certain proportion, while the mixture undergoes advanced oxidation.

[0030] The overall elevation of the integrated device of this invention can be 0 to 3m, and it is mainly built based on the secondary sedimentation tank.

[0031] The second objective of the present invention can be achieved by the following technical solution: a method for treating wastewater using the above-mentioned device, comprising the following steps:

[0032] a) During peak wastewater treatment periods, wastewater from the storage tank is fed into the reverse osmosis membrane tank via the third outlet. The concentrate produced by the reverse osmosis membrane tank is returned to the ozone oxidation tank via a booster pump, control valve, and flow meter. Wastewater treated in the ozone oxidation tank flows into the second buffer tank, is pressurized by the booster pump, and flows into the reverse osmosis membrane tank. After filtration in the reverse osmosis membrane tank, the concentrate is returned to the ozone oxidation tank. After ozone oxidation in the ozone oxidation tank, it is returned to the reverse osmosis membrane tank via the second buffer tank. This process continues until the off-peak wastewater treatment period.

[0033] b) During the off-peak period of wastewater treatment, the concentrate produced in the reverse osmosis membrane tank is returned to the electro-oxidation tank via a booster pump, control valve, and flow meter. The organic pollutants are completely mineralized by electro-oxidation. The wastewater treated in the electro-oxidation tank flows into the first buffer tank, is pressurized by the booster pump, and flows into the reverse osmosis membrane tank. After filtration in the reverse osmosis membrane tank, the concentrate produced is returned to the electro-oxidation tank. After oxidation in the electro-oxidation tank, it is returned to the reverse osmosis membrane tank via the first buffer tank. This process continues until the peak period of wastewater treatment. The effluent from the reverse osmosis membrane tank flows into the reclaimed water tank for reuse.

[0034] To address the problems in existing technologies, such as the high concentrations of ions and organic matter in the concentrate leading to environmental pollution from direct discharge, and the accumulation of contaminants on the membrane resulting in low membrane flux and severely impacting water purification efficiency, leading to significant economic waste, this invention offers a solution using ozone oxidation and electro-oxidation coupled with reverse osmosis membrane technology. Ozone oxidation effectively and rapidly oxidizes and decomposes organic matter and ammonia nitrogen in a short time, featuring short contact time, high oxidation efficiency, and insensitivity to temperature. It also provides functions such as sterilization, deodorization, taste removal, and decolorization. Electro-oxidation is an environmentally friendly advanced oxidation technology. No oxidant needs to be added during water treatment, minimizing the risk of chemical pollution. The reaction conditions are mild, generally carried out at ambient temperature and pressure; it also provides flotation, flocculation, sterilization, and oxidation effects.

[0035] This invention combines the advantages of reverse osmosis membranes and advanced oxidation methods (including ozone oxidation and electro-oxidation). The device is simple, easy to operate and manage, and can effectively utilize chloride ions in wastewater to remove pollutants from the concentrate, continuously alleviate membrane fouling, avoid secondary pollution, and reduce operating costs. The water in the reverse osmosis membrane effluent tank can be used for reclaimed water reuse, reducing the consumption of tap water.

[0036] In the above methods for treating wastewater:

[0037] Furthermore, in order to adjust the concentrations of ammonia nitrogen and chloride ions in the oxidation tank, step a also includes a mixing step: the wastewater in the storage tank is introduced into the ozone oxidation tank or the electro-oxidation tank through a control valve and a flow meter, and mixed with the wastewater concentrate in the ozone oxidation tank or the electro-oxidation tank; or step b also includes a mixing step: the wastewater in the storage tank is introduced into the electro-oxidation tank through a control valve and a flow meter, and mixed with the wastewater concentrate in the electro-oxidation tank.

[0038] Wastewater from the storage tank is introduced into the ozone oxidation tank or electro-oxidation tank through a flow meter and control valve, where it is mixed with the concentrated wastewater.

[0039] Optionally, in steps a to b, the wastewater in the storage tank is introduced into the reverse osmosis membrane tank, and the initial transmembrane pressure is adjusted to 1.2 to 2.0 MPa, and the cross-flow velocity is 7.49 to 14.99 cm / s.

[0040] Optionally, the ozone aeration rate in the ozone oxidation tank in step a is 100 mL / min, and the residence time is 20 min to 60 min.

[0041] Optionally, the catalyst placed in the catalyst placement area of ​​the ozone oxidation tank in step a is manganese dioxide with a content of 20 mg / L.

[0042] Optionally, the ammonia nitrogen concentration of the wastewater in step a is 5–20 mg / L, and the COD concentration is 20–50 mg / L.

[0043] Optionally, the chloride ion concentration in the wastewater described in step a is 100–300 mg / L.

[0044] If the discharged wastewater has excessively high chloride ion concentrations, it can cause significant damage to the reverse osmosis membrane. Through actual wastewater treatment plant analysis and experiments, it has been found that in most wastewater treatment plants, when the chloride ion concentration in the wastewater is between 100 and 300 mg / L, it is less likely to damage the reverse osmosis membrane in the reverse osmosis membrane tank. This is why a certain amount of wastewater (such as raw water from the storage tank) needs to be added when the wastewater in the buffer tank of step a or step b passes through the reverse osmosis membrane again.

[0045] Optionally, the current density in the electro-oxidation cell described in step b is 10–30 mA / cm².2 The electro-oxidation time is 30–60 min.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] (1) This invention combines the advantages of reverse osmosis membrane and advanced oxidation method. The device is simple and easy to operate and manage. It can effectively use advanced oxidation technology to remove pollutants in the concentrate and use chloride ions in the wastewater to generate chloramine to continuously alleviate membrane fouling, avoid secondary pollution and reduce operating costs.

[0048] (2) The water in the reverse osmosis membrane outlet tank of the present invention can be used for greywater reuse, reducing the consumption of tap water;

[0049] (3) The electro-oxidation tank of the present invention does not require the addition of oxidant in the treatment of concentrated liquid, and the ozone oxidation tank only requires the addition of catalyst in the treatment of concentrated liquid. The risk of chemical pollution is small, the reaction conditions are mild, and it is generally carried out at room temperature and pressure. It has the functions of air flotation, flocculation, sterilization and oxidation.

[0050] (4) In this invention, when the sewage inflow rate is large and the pollutant concentration is high, an ozone oxidation tank is selected for oxidation. However, although ozone has a strong oxidation performance, its oxidation is selective. The oxidation products are mostly small molecule acids, which make it difficult to achieve complete mineralization of organic pollutants. The pollutants remain in the concentrate. Therefore, when the sewage inflow rate is small, it is best to select an electro-oxidation tank to further oxidize the concentrate. Electro-oxidation can completely mineralize organic pollutants.

[0051] (5) In general, the present invention utilizes advanced oxidation technology to oxidize wastewater concentrate and further couples it with reverse osmosis technology to achieve excellent removal of ammonia nitrogen, chloride ions and organic matter. No additional reagents are required, which can effectively avoid secondary pollution. It has a high removal rate, stable operation, and convenient management and maintenance, and has excellent economic benefits and environmental advantages. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the integrated device for deep wastewater treatment using advanced oxidation-coupled reverse osmosis membrane technology in Example 1;

[0053] Figure 2 for Figure 1 A schematic diagram of the electro-oxidation cell structure in the diagram;

[0054] Figure 3 for Figure 1 Schematic diagram of the structure of a medium-ozone oxidation pond;

[0055] Figure 4 for Figure 1 Schematic diagram of the reverse osmosis membrane tank structure;

[0056] In the diagram: 1—Water storage tank; 2—Control valve; 3—Liquid flow meter; 4—Electro-oxidation tank; 4-1—Perforated baffle; 4-2—Anode; 4-3—Cathode; 5—Power supply; 61—First buffer tank; 62—Second buffer tank; 7—Boost pump; 8—Reverse osmosis membrane tank; 9—Grey water reuse tank; 10—Ozone tank; 10-1—Pure oxygen generator; 10-2—Baffle; 10-3—Perforated baffle; 11—Ozone generator; 12—Gas flow meter; 13—Automatic control mechanism (PLC); 14—Membrane tank inlet pipe; 15—Membrane module; 16—Drain valve; 17—Concentrate return pipe; 18—Membrane tank outlet pipe. Detailed Implementation

[0057] The technical solution of this invention is not limited to the specific methods listed below, and the scale and design can be flexibly changed according to the actual situation.

[0058] Example 1

[0059] The present invention will now be described in conjunction with the accompanying drawings. The following description is merely illustrative and explanatory and should not be construed as limiting the scope of protection of the present invention.

[0060] like Figure 1 An integrated device for deep wastewater treatment using advanced oxidation-coupled reverse osmosis membrane technology, comprising:

[0061] Water storage tank 1, electro-oxidation tank 4, power supply 5, ozone oxidation tank 10, ozone generator 11, first buffer tank 61, second buffer tank 62, reverse osmosis membrane tank 8, greywater reuse tank 9, and automatic control mechanism 13;

[0062] The water storage tank 1 has four outlets, wherein the first outlet and the third outlet are connected to the inlet of the reverse osmosis membrane tank 8 through pipes, the second outlet is connected to the first inlet of the electro-oxidation tank 4 through a pipe, and the fourth outlet is connected to the first inlet of the ozone oxidation tank 10 through a pipe.

[0063] The pipeline connecting the water storage tank 1 to the reverse osmosis membrane tank 8 is equipped with a control valve 2, a flow meter 3 and a booster pump 7. The pipeline connecting the water storage tank 1 to the electro-oxidation tank 4 or the ozone oxidation tank 10 is equipped with a control valve 2 and a flow meter 3.

[0064] The electro-oxidation cell 4 is powered by the power source 5, and the outlet end of the electro-oxidation cell 4 is connected to the inlet end of the first buffer cell 61 through a pipe.

[0065] A control valve 2 is installed on the pipeline connecting the electro-oxidation tank 4 and the first buffer tank 61;

[0066] The ozone oxidation tank 10 is supplied with ozone by the ozone generator 11, and the outlet end of the ozone oxidation tank 10 is connected to the inlet end of the second buffer tank 62 through a pipeline.

[0067] A control valve 2 is installed on the pipe connecting the ozone oxidation tank 10 and the second buffer tank 62;

[0068] A gas flow meter 12 is installed on the pipe connecting the ozone oxidation tank 10 and the ozone generator 11.

[0069] The outlet ends of the first buffer tank 61 and the second buffer tank 62 are connected to the inlet end of the reverse osmosis membrane tank 8 through pipes.

[0070] A control valve 2 and a booster pump 7 are installed on the pipe connecting the first buffer tank 61 or the second buffer tank 62 to the reverse osmosis membrane tank 8.

[0071] The reverse osmosis membrane tank 8 has two outlet ends. One outlet end is connected to the inlet end of the wastewater reuse tank 9 through a pipe, and the other outlet end is connected to the second inlet end of the ozone oxidation tank 10 or the oxidation tank 4 through a pipe. This is used to return the concentrate in the reverse osmosis membrane tank 8 to the ozone oxidation tank 10 or the electro-oxidation tank 4.

[0072] The pipeline connecting the reverse osmosis membrane tank 8 to the ozone oxidation tank 10 or the electro-oxidation tank 4 is equipped with a control valve 2, a flow meter 3 and a booster pump 7;

[0073] The pipeline connecting the reverse osmosis membrane tank 8 and the greywater reuse tank 9 is equipped with a control valve 2 and a flow meter 3.

[0074] Control valve 2, flow meter 3, booster pump 7, and gas flow meter 12 are all connected to and controlled by automatic control mechanism 13.

[0075] like Figure 2 As shown, the electro-oxidation cell 4 includes an electro-oxidation cell perforated partition 4-1, an anode 4-2, and a cathode 4-3. The anode 4-2 is connected to the positive terminal of the power supply 5, and the cathode 4-3 is connected to the negative terminal of the power supply 5.

[0076] In this embodiment, a boron-doped diamond electrode is used as the anode, and a ruthenium-titanium coated electrode is used as the cathode.

[0077] like Figure 3 As shown, the ozone oxidation tank 10 includes a baffle 10-2 and an ozone oxidation tank perforated baffle 10-3, and a catalyst placement area is provided between the baffle 10-2 and the ozone oxidation tank perforated baffle 10-3.

[0078] The catalyst in the catalyst placement area is manganese dioxide.

[0079] The ozone generator 11 is supplied with gas by the pure oxygen generator 10-1, and an exhaust gas collection pipe is provided above the tail end of the ozone generation tank.

[0080] like Figure 4As shown, the reverse osmosis membrane tank 8 includes a membrane module 15. Below the membrane module 15 is a membrane tank inlet pipe 14 connected to the water storage tank 1, the first buffer tank 61, or the second buffer tank 62. Above the membrane module 15 is a concentrate return pipe 18 connected to the electro-oxidation tank 4 or the ozone oxidation tank 10. The concentrate return pipe 18 is equipped with a drain valve 16. Above the membrane module 15 is also a membrane tank outlet pipe 17 connected to the greywater reuse tank 9.

[0081] In the event of excessive concentrate volume during operation, drain valve 16 can discharge the excess reverse osmosis concentrate when the initial concentrate volume reaches the specified level.

[0082] The reverse osmosis membrane used in membrane module 15 is an organic membrane and cannot be an aromatic polyamide membrane.

[0083] The method for treating wastewater using the above-mentioned device includes the following steps:

[0084] a) During peak wastewater treatment periods, wastewater in storage tank 1 is fed into reverse osmosis membrane tank 8 via the third outlet. The concentrate produced in reverse osmosis membrane tank 8 is returned to ozone oxidation tank 10 via booster pump 7, control valve 2, and flow meter 3. Wastewater treated in ozone oxidation tank flows into second buffer tank 62, is pressurized by booster pump 7, and flows into reverse osmosis membrane tank 8. After filtration in reverse osmosis membrane tank 8, the concentrate is returned to ozone oxidation tank 10. After ozone oxidation in ozone oxidation tank 10, it is returned to reverse osmosis membrane tank 8 via second buffer tank 62. This process continues until the non-peak wastewater treatment period.

[0085] b) During the off-peak period of wastewater treatment, the concentrate produced in the reverse osmosis membrane tank 8 is returned to the electro-oxidation tank 4 via the lift pump 7, control valve 2 and flow meter 3. The organic pollutants are completely mineralized by electro-oxidation. The wastewater treated in the electro-oxidation tank 4 flows into the first buffer tank 61, and is then pressurized by the lift pump 7 and flows into the reverse osmosis membrane tank 8. After filtration in the reverse osmosis membrane tank 8, the concentrate is returned to the electro-oxidation tank 4. After oxidation in the electro-oxidation tank 4, it is returned to the reverse osmosis membrane tank via the first buffer tank 61. This process continues until the peak period of wastewater treatment. The effluent from the reverse osmosis membrane tank flows into the reclaimed water tank for reuse.

[0086] Step a also includes a mixing step: the wastewater in the storage tank 1 is introduced into the ozone oxidation tank 10 through the control valve 2 and the flow meter 3, and mixed with the wastewater concentrate in the ozone oxidation tank 10.

[0087] Step b also includes a mixing step: the wastewater in the storage tank 1 is introduced into the electro-oxidation tank 4 through the control valve 2 and the flow meter 3, and mixed with the wastewater concentrate in the electro-oxidation tank 4.

[0088] In steps a to b, the wastewater in the storage tank 1 is introduced into the reverse osmosis membrane tank 8, and the initial transmembrane pressure is adjusted to 1.2 to 2.0 MPa, and the cross-flow velocity is 7.49 to 14.99 cm / s.

[0089] In step a, the ozone aeration rate in the ozone oxidation tank is 100 mL / min, and the residence time is 20 min to 60 min.

[0090] The wastewater described in step a has an ammonia nitrogen concentration of 5–20 mg / L, a COD concentration of 20–50 mg / L, and a chloride ion concentration of 100–300 mg / L.

[0091] The current density in the electro-oxidation cell 4 described in step b is 10–30 mA / cm². 2 The electro-oxidation time is 30–60 min.

[0092] In the initial stage of operation, the wastewater in the water storage tank 1 needs to be concentrated. The flow rate of the concentrated liquid is controlled by the control valve 2 and the flow meter 3. When the concentrated liquid accumulates to a certain value, the control valve 2 is closed by the automatic control mechanism 13.

[0093] The overall elevation of this integrated device is 0-3m, and it is mainly built on the secondary sedimentation tank of the sewage treatment plant.

[0094] In practice, the effluent from the secondary sedimentation tank is collected in the storage tank 1. The water in the storage tank 1 first enters the reverse osmosis membrane tank 8 for concentration and filtration. The concentrate flows into the ozone oxidation tank 10. The flow rate of the concentrate is controlled by the concentrate return control valve 2 and the flow meter 3. When the concentrate accumulates to a certain value, the inlet valve 2 is closed by the automatic control system 13.

[0095] The electro-oxidation tank 4 is powered by the power source 5. The mixed liquid reacts in the electro-oxidation tank 4, where pollutants such as ammonia nitrogen are removed.

[0096] The ozone oxidation tank 10 is supplied with ozone by the ozone generator 11. The mixed liquid reacts in the ozone oxidation tank 10, and pollutants such as ammonia nitrogen and organic matter are removed here.

[0097] The selection of an advanced oxidation tank is controlled by the concentrations of ammonia nitrogen, chloride ions, organic matter, and influent flow rate in the water. When the influent flow rate is large or the pollutant concentration is high (such as during the daytime or peak sewage treatment period), an ozone oxidation tank is selected. After the system has run for several cycles, some sewage (raw water) can be added back from the storage tank to adjust the concentrate to match the treatment capacity of the oxidation tank and achieve the cleaning effect on the membrane.

[0098] Although ozone has strong oxidizing properties, its oxidation is selective, and the oxidation products are mostly small-molecule acids, making it difficult to completely mineralize organic pollutants, which remain in the concentrate. Therefore, when the wastewater inflow is low (such as at night, during off-peak wastewater treatment periods), an electro-oxidation tank is used to further oxidize the concentrate, which can completely mineralize organic pollutants.

[0099] After oxidation, the water flows into the first buffer tank 61 or the second buffer tank 62 through the control valve 2, and then flows into the reverse osmosis membrane tank 8 through the membrane tank inlet pipe 14. It is filtered by the membrane module 15. The membrane tank inlet pipe 14 has a booster pump 7, which can transport the water in the first buffer tank 61 or the second buffer tank 62 to the membrane module 15. Excess concentrate can be discharged through the drain valve 16 on the concentrate return pipe 18. The reverse osmosis effluent flows into the greywater reuse tank 9 through the membrane tank outlet pipe 17, and can be used for greywater reuse.

[0100] Example 2

[0101] The method for treating wastewater using the integrated device for advanced oxidation-coupled reverse osmosis membrane technology described in Example 1 includes the following steps:

[0102] The raw water (i.e., the wastewater in storage tank 1) was measured to have a pH of 7.00, conductivity of 5.12 (mS / cm), NH3-N of 5.2 mg / L, COD of 45 mg / L, and Cl- concentration of 100 mg / L. - =300mg / L.

[0103] After the raw water is filtered in the reverse osmosis membrane tank 8 and treated in the ozone oxidation tank 10, the concentrate flows into the electro-oxidation tank 4, where it is subjected to oxidation at a temperature of 29℃ and a current density of 30mA / cm³. 2 Under certain conditions, the influent was electro-oxidized for 60 minutes, and then the treated effluent was collected. The effluent NH3-N = 0.84 mg / L.

[0104] The measured values ​​of NH3-N in the effluent from electro-oxidation were 0.24 mg / L, free chlorine was 154.85 mg / L, and the contents of nitrate nitrogen and nitrite nitrogen in the water were both less than 0.1 mg / L. It can be inferred that ammonia nitrogen was converted into nitrogen gas and released into the environment.

[0105] The effluent from electro-oxidation is fed into the first buffer tank 61, along with three times the volume of raw water. It then passes through a reverse osmosis membrane in the reverse osmosis membrane tank 8. Measurements show a pH of 8-9, conductivity of approximately 15 μS / cm, NH3-N of approximately 0.1 mg / L, and COD of 0-2 mg / L. This demonstrates that the device has a high removal rate of NH3-N from wastewater and also effectively removes chloride ions and organic matter.

[0106] The above examples illustrate the present invention. It is important to note that these specific embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention. Non-essential modifications and adjustments made by others based on the present invention still fall within the scope of protection of the present invention.

Claims

1. A method for treating wastewater using an integrated device that utilizes electro-oxidation coupled with reverse osmosis membrane technology for deep wastewater treatment, characterized in that: Includes the following steps: a) During the peak period of wastewater treatment, the wastewater in the storage tank (1) enters the reverse osmosis membrane tank (8) through the third outlet end. The concentrate produced by the reverse osmosis membrane tank (8) is returned to the ozone oxidation tank (10) through the lift pump (7), control valve (2) and flow meter (3). The wastewater treated by the ozone oxidation tank (10) flows into the second buffer tank (62), and is pressurized by the lift pump (7) and flows into the reverse osmosis membrane tank (8). After being filtered by the reverse osmosis membrane tank (8), the concentrate produced is returned to the ozone oxidation tank (10). After being oxidized by ozone in the ozone oxidation tank (10), it is returned to the reverse osmosis membrane tank (8) through the second buffer tank (62). This process continues until the non-peak period of wastewater treatment. b) During the non-peak period of wastewater treatment, the concentrate produced in the reverse osmosis membrane tank (8) is returned to the electro-oxidation tank (4) via the booster pump (7), control valve (2) and flow meter (3). The organic pollutants are completely mineralized by electro-oxidation. The wastewater treated in the electro-oxidation tank (4) flows into the first buffer tank (61), and is pressurized by the booster pump (7) and flows into the reverse osmosis membrane tank (8). After being filtered by the reverse osmosis membrane tank (8), the concentrate is returned to the electro-oxidation tank (4). After being oxidized by the electro-oxidation tank (4), it is returned to the reverse osmosis membrane tank via the first buffer tank (61). This process continues until the peak period of wastewater treatment. The effluent from the reverse osmosis membrane tank flows into the reclaimed water tank for reuse. The integrated device for deep wastewater treatment using advanced oxidation-coupled reverse osmosis membrane technology includes: Water storage tank (1), electro-oxidation tank (4), power supply (5), ozone oxidation tank (10), ozone generator (11), first buffer tank (61), second buffer tank (62), reverse osmosis membrane tank (8), greywater reuse tank (9) and automatic control mechanism (13). The water storage tank (1) has four outlets, wherein the first outlet and the third outlet are connected to the inlet of the reverse osmosis membrane tank (8) through pipes, the second outlet is connected to the first inlet of the electro-oxidation tank (4) through pipes, and the fourth outlet is connected to the first inlet of the ozone oxidation tank (10) through pipes. The pipeline connecting the water storage tank (1) to the reverse osmosis membrane tank (8) is equipped with a control valve (2), a flow meter (3) and a booster pump (7). The pipeline connecting the water storage tank (1) to the electro-oxidation tank (4) or the ozone oxidation tank (10) is equipped with a control valve (2) and a flow meter (3). The electro-oxidation cell (4) is powered by a power source (5), and the outlet end of the electro-oxidation cell (4) is connected to the inlet end of the first buffer tank (61) through a pipe. The ozone oxidation tank (10) is supplied with ozone by the ozone generator (11), and the outlet end of the ozone oxidation tank (10) is connected to the inlet end of the second buffer tank (62) through a pipe. A gas flow meter (12) is installed on the pipe connecting the ozone oxidation tank (10) and the ozone generator (11). The outlet ends of the first buffer tank (61) and the second buffer tank (62) are connected to the inlet end of the reverse osmosis membrane tank (8) through pipes; The reverse osmosis membrane tank (8) has two outlet ends, one of which is connected to the inlet end of the wastewater reuse tank (9) through a pipe, and the other outlet end is connected to the second inlet end of the ozone oxidation tank (10) or the oxidation tank (4) through a pipe, for returning the concentrate in the reverse osmosis membrane tank (8) to the ozone oxidation tank (10) or the electro-oxidation tank (4); The pipeline connecting the reverse osmosis membrane tank (8) to the ozone oxidation tank (10) or the electro-oxidation tank (4) is equipped with a control valve (2), a flow meter (3) and a booster pump (7). The control valve (2), flow meter (3), booster pump (7), and gas flow meter (12) are all connected to and controlled by the automatic control mechanism (13).

2. The method according to claim 1, characterized in that: Step a further includes a mixing step: the wastewater in the storage tank (1) is introduced into the ozone oxidation tank (10) through the control valve (2) and the flow meter (3) and mixed with the wastewater concentrate in the ozone oxidation tank (10); Step b further includes a mixing step: the wastewater in the storage tank (1) is introduced into the electro-oxidation tank (4) through the control valve (2) and the flow meter (3) and mixed with the wastewater concentrate in the electro-oxidation tank (4).

3. The method according to claim 1, characterized in that: In steps a to b, the wastewater in the storage tank (1) is introduced into the reverse osmosis membrane tank (8), and the initial transmembrane pressure is adjusted to 1.2~2.0MPa and the crossflow velocity is 7.49~14.99 cm / s.

4. The method according to claim 1, characterized in that: The wastewater described in step a has an ammonia nitrogen concentration of 5-20 mg / L, a COD concentration of 20-50 mg / L, and a chloride ion concentration of 100-300 mg / L.

5. The method according to claim 1, characterized in that: step The current density in the electro-oxidation cell (4) described in b is 10~30 mA / cm². 2 The electro-oxidation time is 30~60 min.

6. The method according to claim 1, characterized in that: A control valve (2) is provided on the pipe connecting the electro-oxidation tank (4) to the first buffer tank (61). A control valve (2) is provided on the pipe connecting the ozone oxidation tank (10) to the second buffer tank (62). A control valve (2) and a booster pump (7) are provided on the pipe connecting the first buffer tank (61) or the second buffer tank (62) to the reverse osmosis membrane tank (8). A control valve (2) and a flow meter (3) are provided on the pipe connecting the reverse osmosis membrane tank (8) to the greywater reuse tank (9).

7. The method according to claim 1, characterized in that: The electro-oxidation cell (4) includes an electro-oxidation cell perforated partition (4-1), an anode (4-2), and a cathode (4-3). The anode (4-2) is connected to the positive terminal of the power supply (5), and the cathode (4-3) is connected to the negative terminal of the power supply (5).

8. The method according to claim 1, characterized in that: The ozone oxidation tank (10) includes a baffle (10-2) and an ozone oxidation tank perforated baffle (10-3), and a catalyst placement area is provided between the baffle (10-2) and the ozone oxidation tank perforated baffle (10-3).

9. The method according to claim 1, characterized in that: The reverse osmosis membrane tank (8) includes a membrane module (15). Below the membrane module (15) is a membrane tank inlet pipe (14) connected to the water storage tank (1), the first buffer tank (61), or the second buffer tank (62). Above the membrane module (15) is a concentrate return pipe (18) connected to the electro-oxidation tank (4) or the ozone oxidation tank (10). The concentrate return pipe (18) is equipped with a drain valve (16). Above the membrane module (15) is also a membrane tank outlet pipe (17) connected to the greywater reuse tank (9).

Images