Nanofiltration equipment with protective film function and sewage treatment system comprising nanofiltration equipment

Abstract

The utility model discloses nanofiltration equipment with a protective membrane function, the nanofiltration equipment with the protective membrane function comprises a water inlet pipe, an ORP meter (1), a nanofiltration module and a reducing agent adding part (3), the water inlet pipe is communicated with the nanofiltration module and is used for inputting water to be treated to the nanofiltration module, the ORP meter (1) is arranged on the water inlet pipe, and the reducing agent adding part (3) is arranged on the water inlet pipe. The ORP meter (1) is located at the front end of the nanofiltration module, the reducing agent adding component (3) is communicated with the water inlet pipe, and the ORP meter (1) is electrically connected with the reducing agent adding component (3); the ORP meter (1) is used for detecting the oxidation reduction potential in a water inlet pipe of the nanofiltration module and controlling the reducing agent adding component (3). The nanofiltration equipment with the protective membrane function can detect and find that residual chlorine is contained in a water body to be treated, Cl2 is changed into Cl <-> in an ionic state by adding a reducing agent, and the protective effect on a nanofiltration reverse osmosis membrane is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to nanofiltration field, specifically, relate to a kind of nanofiltration equipment with protective film function and including its sewage treatment system. BACKGROUND

[0002] Membrane technology has nearly 70 years history since 1950s, and nanofiltration reverse osmosis is indispensable as a kind of membrane technology for deep desalination of water treatment, and is widely used in many fields, from seawater desalination to industrial wastewater treatment, which cannot be separated from this technology, and nanofiltration and reverse osmosis membrane have irreplaceable role in ensuring water quality, energy saving and emission reduction due to high precision and stability.

[0003] Currently, residual chlorine and other oxidizing substances are often contained in domestic sewage, and these domestic sewage needs to be filtered through nanofiltration modules. However, the current nanofiltration reverse osmosis membrane has certain resistance to acid and alkali, but has poor resistance to residual chlorine and other oxidizing substances. Since the nanofiltration reverse osmosis membrane usually uses polyamide material as an ultra-thin separation layer to provide desalination and separation performance, the polyamide ultra-thin separation layer is particularly sensitive to residual chlorine, and the strong oxidizing property of residual chlorine can cause membrane perforation and damage the structure of the membrane. At the same time, residual chlorine can also lower the oxidation-reduction potential in water, accelerate the attachment and generation of pollutants on the membrane, and cause water quality to decrease. Residual chlorine can even react with the reverse osmosis membrane material, causing degradation of the membrane material and thus reducing the desalination efficiency and service life of the membrane. Therefore, how to improve the service life of the nanofiltration module in the process of treating domestic sewage is a problem to be solved. SUMMARY

[0004] The utility model aims at providing a kind of nanofiltration equipment with protective film function and including its sewage treatment system, which can detect and find residual chlorine in water to be treated, and make Cl2 into ion state Cl - By adding reducing agent, the protective effect of nanofiltration reverse osmosis membrane is realized.

[0005] To achieve the above purpose, the utility model provides a kind of nanofiltration equipment with protective film function, which comprises a water inlet pipe, an ORP meter, a nanofiltration module and a reducing agent adding part. The water inlet pipe is communicated with the nanofiltration module for inputting water to be treated into the nanofiltration module. The ORP meter is arranged on the water inlet pipe and located at the front end of the nanofiltration module. The reducing agent adding part is communicated with the water inlet pipe, and the ORP meter is electrically connected with the reducing agent adding part.

[0006] The ORP meter detects the oxidation-reduction potential in the water inlet pipe of the nanofiltration module, and the ORP meter controls the reducing agent adding part.

[0007] Preferably, the ORP meter is provided with a control set value, and when the value detected by the ORP meter is higher than the control set value, the ORP meter controls the reducing agent adding component to be opened.

[0008] Preferably, the reducing agent adding component comprises a first meter, which controls the adding amount of reducing agent.

[0009] Preferably, the nanofiltration module comprises a water inlet pump, a pre-filter, a high-pressure water pump, a circulating pump and a nanofiltration membrane group, the water inlet pump is arranged on the water inlet pipe and located at the front end of the pre-filter, one end of the high-pressure water pump is connected with the outlet of the pre-filter, and the other end is connected with the first inlet of the circulating pump, the outlet of the circulating pump is connected with the second inlet of the nanofiltration membrane group, the first outlet of the nanofiltration membrane group is connected with the first inlet, and the second outlet of the nanofiltration module outputs clean liquid.

[0010] Preferably, a first pressure sensor is arranged between the circulating pump and the nanofiltration membrane group.

[0011] Preferably, a second pressure sensor is arranged at the first outlet.

[0012] Preferably, a first flow meter is arranged at the second outlet.

[0013] The utility model also provides a sewage treatment system, the sewage treatment system includes the pretreatment equipment, anaerobic treatment equipment, biochemical treatment equipment, ultrafiltration equipment, the nanofiltration equipment with the protection film function, reverse osmosis equipment and DTRO equipment which are connected gradually, the clean liquid outlet of ultrafiltration equipment is connected with water inlet pipe, the second outlet is connected with reverse osmosis equipment.

[0014] Preferably, the ultrafiltration equipment comprises a chlorination component, the chlorination component is provided with a second meter, and the second meter is electrically connected with the first meter.

[0015] Preferably, the ORP meter is arranged behind the reducing agent adding component.

[0016] According to the technical scheme, the ORP meter can detect the oxidation-reduction potential in the water inlet pipe and reflect the concentration of oxidizing substances in water. When oxidizing substances exist in water, the ORP value will increase; on the contrary, if reducing substances exist in water, the ORP value will decrease. When the content of oxidizing substances in the water inlet of the nanofiltration system is too high, the ORP meter displays a value that increases, and when the value displayed by the ORP meter exceeds a limited value, the ORP meter controls the reducing agent adding component to be opened, the reducing agent is added, and oxidation-reduction reaction occurs between the reducing agent and oxidizing substances such as residual chlorine in water, so that the oxidizing substances in water are removed, the nanofiltration membrane and subsequent reverse osmosis membrane and DTRO membrane are prevented from being oxidized and perforated, and the membrane structure is prevented from being damaged, thereby improving the service life of the nanofiltration membrane.

[0017] The reducing agent can be sodium bisulfite, sulfur dioxide or the like, which can be added to react with oxidizing substances in water, thereby reducing the oxidizing substances and reducing the ORP value.

[0018] Specifically, the oxidation-reduction reaction process is that the reducing agent reacts with chlorine, peroxide and other oxidizing substances in water to reduce them into harmless substances or substances with lower oxidation states. For example:

[0019] Sodium bisulfite (NaHSO3) can reduce residual chlorine (Cl2) in water into chloride ions (Cl-).

[0020] Sulfur dioxide (SO2) can reduce peroxide (such as H2O2) into water.

[0021] Preferably, two ORP meters can be arranged at the front end and the rear end of the reducing agent adding component, and are arranged to be far away from the reducing agent adding component, so that after the reducing agent adding component adds the reducing agent, there is enough time for the reducing agent to react with water in the water inlet pipe to complete the treatment of water entering the nanofiltration module.

[0022] The ORP meter at the front end of the reducing agent adding component is used to control the start of the ORP meter, and when the value detected by the ORP meter at the front end is too high, the reducing agent adding component is immediately controlled to add reducing agent to the water body. The ORP meter at the rear end detects the oxidation-reduction potential of the water body after the reaction, and when the oxidation-reduction potential detected by the ORP meter at the rear end has returned to a reasonable level, a signal is sent to control the reducing agent adding component to stop adding reducing agent. If the oxidation-reduction potential detected by the ORP meter at the rear end is still very high, the difference between the detected value and the control set value is controlled to control the amount of reducing agent added by the reducing agent adding component. If the above difference is large, the reducing agent adding component is controlled to increase the amount of reducing agent added, and if the above difference is small, the reducing agent adding component can be adjusted to reduce the amount of reducing agent added.

[0023] More preferably, the ORP meter located at the rear is arranged at the front end of the nanofiltration membrane to directly detect the oxidation-reduction potential of the water entering the nanofiltration membrane, so as to remove the oxidation of the water entering the nanofiltration membrane by controlling the reducing agent adding part.

[0024] Therefore, in the nanofiltration equipment with a protective film function, the ORP meter monitors the oxidation-reduction state of the water quality in real time. When the ORP value is too high, it indicates that the concentration of oxidizing substances in the water is too high, and reducing agents need to be added to neutralize these oxidizing substances, thereby removing excess oxidizing substances, restoring the stability of the water quality, and ensuring the normal operation of the system. This control method can effectively avoid the corrosion of oxidizing substances on the membrane material and the influence of water treatment effect.

[0025] Other features and advantages of the present application will be described in detail in the following specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, and are used to explain the present application together with the following specific embodiments, but do not constitute a limitation to the present application. In the drawings:

[0027] Figure 1 It is a schematic diagram of a nanofiltration equipment with a protective film function;

[0028] Figure 2 It is a schematic diagram of a circulating pump and nanofiltration membrane group connection;

[0029] Figure 3 It is a working flow chart of a sewage treatment system.

[0030] BRIEF DESCRIPTION OF DRAWINGS

[0031] 1 ORP meter 21 water inlet pump

[0032] 3 reducing agent adding part 22 prefilter

[0033] 23 high-pressure water pump 24 circulating pump

[0034] 25 nanofiltration membrane group 4 pretreatment equipment

[0035] 5 anaerobic treatment equipment 6 biochemical treatment equipment

[0036] 7 ultrafiltration equipment 8 reverse osmosis equipment

[0037] 9 DTRO equipment 252 first outlet

[0038] 253 second outlet 241 first inlet

[0039] 251 second inlet 2 nanofiltration equipment

[0040] 26 first flow meter 28 second pressure sensor

[0041] 27 first pressure sensor DETAILED DESCRIPTION

[0042] The specific embodiments described hereinbelow are illustrative only and are not intended to limit the scope of the present application. It should be understood that various modifications can be made to the procedures and assemblies described herein without departing from the spirit of the application.

[0043] In the present application, unless otherwise specified, the orientation words contained in the terms such as "front end" and "rear" only represent the orientation of the terms in the normal use state or the common name understood by those skilled in the art, and should not be regarded as a limitation of the terms.

[0044] Referring to Figure 1 The nanofiltration equipment with the protection film function comprises a water inlet pipe, an ORP meter 1, a nanofiltration module and a reducing agent adding part 3. The water inlet pipe is communicated with the nanofiltration module and is used for inputting water to be treated to the nanofiltration module. The ORP meter 1 is arranged on the water inlet pipe and is located at the front end of the nanofiltration module. The reducing agent adding part 3 is communicated with the water inlet pipe. The ORP meter 1 is electrically connected with the reducing agent adding part 3.

[0045] The ORP meter 1 detects the oxidation-reduction potential in the water inlet pipe of the nanofiltration module. The ORP meter 1 controls the reducing agent adding part 3.

[0046] Through the implementation of the above technical solution, the ORP meter 1 can detect the oxidation-reduction potential in the water inlet pipe and reflect the concentration of oxidizing substances in the water. When there are oxidizing substances in the water, the ORP value will rise. Conversely, if there are reducing substances in the water, the ORP value will decrease. When the content of oxidizing substances in the water inlet of the nanofiltration system is too high, the displayed value of the ORP meter 1 will increase. When the displayed value of the ORP meter 1 exceeds the limited value, the ORP meter 1 controls the reducing agent adding part 3 to open, and the reducing agent is added to have an oxidation-reduction reaction with the oxidizing substances such as residual chlorine in the water, so as to remove the oxidizing substances in the water, thereby avoiding the oxidation perforation of the nanofiltration membrane and the subsequent reverse osmosis membrane and DTRO membrane, and the damage of the membrane structure, and thus improving the service life of the nanofiltration membrane.

[0047] The reducing agent can be sodium bisulfite, sulfur dioxide and the like. These reducing agents can have an oxidation-reduction reaction with the oxidizing substances in the water after being added, so as to reduce the oxidizing substances and reduce the ORP value.

[0048] The specific oxidation-reduction reaction process is that the reducing agent in the water will have a reaction with chlorine, peroxide and other oxidizing substances, so as to reduce them into harmless substances or substances with lower oxidation states. For example:

[0049] Sodium bisulfite (NaHSO3) can reduce residual chlorine (Cl2) in water to chloride ion (Cl - ).

[0050] Sulfur dioxide (SO2) can reduce peroxide (such as H2O2) to water.

[0051] Preferably, two ORP meters 1 are provided, one at the front end of the reducing agent adding component 3 and the other at the rear end of the reducing agent adding component 3, and are set to be far away from the reducing agent adding component 3, so that after the reducing agent adding component 3 adds the reducing agent, there is enough time for the reducing agent to chemically react with the water in the water inlet pipe, completing the treatment of the water entering the nanofiltration module.

[0052] The ORP meter 1 at the front end of the reducing agent adding component 3 is used to control the start of the ORP meter 1, and when the value detected by the ORP meter 1 at the front end is too high, the reducing agent adding component 3 is immediately controlled to add reducing agent to the water body. The ORP meter 1 at the rear end detects the oxidation-reduction potential of the water body after the reaction, and when the oxidation-reduction potential detected by the ORP meter 1 at the rear end has returned to a reasonable level, a signal is sent to control the reducing agent adding component 3 to stop adding reducing agent. If the oxidation-reduction potential detected by the ORP meter 1 at the rear end is still very high, the difference between the detected value and the control set value is used to control the amount of reducing agent added by the reducing agent adding component 3. If the above difference is large, the reducing agent adding component 3 is controlled to increase the amount of reducing agent added, and if the above difference is small, the reducing agent adding component 3 can be adjusted to reduce the amount of reducing agent added.

[0053] More preferably, the ORP meter 1 at the rear end is provided at the front end of the nanofiltration membrane, directly detecting the oxidation-reduction potential of the water body entering the nanofiltration membrane, so as to remove the oxidation of the water body entering the nanofiltration membrane by controlling the reducing agent adding component 3.

[0054] Therefore, in the nanofiltration equipment with a protective film function, the ORP meter 1 monitors the oxidation-reduction state of the water quality in real time. When the ORP value is too high, it indicates that the concentration of oxidizing substances in the water is too high, and reducing agent needs to be added to neutralize these oxidizing substances, thereby removing excess oxidizing substances and restoring the stability of the water quality to ensure normal operation of the system. This control method can effectively avoid the corrosion of oxidizing substances on the membrane material and the influence on the water treatment effect.

[0055] In this fact way, preferably, the ORP meter 1 is provided with a control set value, and when the value detected by the ORP meter 1 is higher than the control set value, the ORP meter 1 controls the reducing agent adding component 3 to start.

[0056] The ORP meter 1 can monitor the oxidation-reduction potential in the water in real time, reflecting the concentration of oxidizing substances in the water.

[0057] When oxidizing substances exist in the water, the ORP value will rise. Conversely, if reducing substances exist in the water, the ORP value will drop. Moreover, the ORP value can reflect the strength of the oxidation or reduction of the water.

[0058] The ORP meter 1 is provided with a control set value. Only when the oxidation is strong enough to affect the nanofiltration membrane, the reducing agent adding part 3 needs to be started to add reducing agent to the water.

[0059] In this embodiment, preferably, the reducing agent adding part 3 comprises a first metering device, which controls the amount of reducing agent added.

[0060] When the ORP meter 1 measures a higher value of the water, the oxidation of the water is very strong, and the residual chlorine content is high, the reducing agent adding part 3 needs to add more reducing agent to the water inlet pipe. By setting the first metering device, the amount of reducing agent added can be quantified. When the ORP meter 1 measures a higher value, the first metering device is controlled to add a larger amount of reducing agent. When the ORP meter 1 measures a smaller value, the first metering device is controlled to add a smaller amount of reducing agent.

[0061] Preferably, corresponding to the value measured by the ORP meter 1, the amount of reducing agent added is set. The amount of reducing agent added can be obtained by theoretical calculation at the initial production. During the production process, by setting the ORP meter 1 near the nanofiltration membrane to monitor the oxidation-reduction potential of the water after the reducing agent is added, the set amount of reducing agent added can be revised according to the monitoring results to obtain a more reasonable amount of reducing agent added corresponding to the value measured by the ORP meter 1, so as to achieve the residual chlorine removal treatment of the water at the minimum cost.

[0062] In this embodiment, preferably, the nanofiltration module comprises a water inlet pump 21, a pre-filter 22, a high-pressure water pump 23, a circulating pump 24 and a nanofiltration membrane group 25. The water inlet pump 21 is arranged on the water inlet pipe and located at the front end of the pre-filter 22. One end of the high-pressure water pump 23 is connected with the outlet of the pre-filter 22, and the other end is connected with the first inlet 241 of the circulating pump 24. The outlet of the circulating pump 24 is connected with the second inlet 251 of the nanofiltration membrane group 25. The first outlet 252 of the nanofiltration membrane group 25 is connected with the first inlet 241. The second outlet 253 of the nanofiltration module outputs the clear liquid.

[0063] The water inlet pump 21 pumps the water to be treated into the nanofiltration module through the water inlet pipe. After the water enters the nanofiltration module, it is first filtered by the pre-filter 22 to remove larger particulate impurities such as suspended solids, silt, rust, etc. By setting the pre-filter 22 to filter the water, it can prevent large particles from clogging the membrane pores or causing physical damage to the membrane, thereby effectively prolonging the service life of the nanofiltration membrane.

[0064] Since the nanofiltration process requires high pressure to effectively separate the dissolved substances in the water. Therefore, a high-pressure water pump 23 is needed to pressurize the water treated by the pre-filter 22 to the required working pressure, usually between 4-30 bar, the specific pressure value depends on the water quality and the type of nanofiltration membrane. The high-pressure water pump 23 not only pressurizes the water, but also needs to ensure that the flow in the water inlet pipe meets the needs of the nanofiltration module, so as to ensure the filtration efficiency of the nanofiltration module.

[0065] The water increased by the high-pressure water pump 23 is delivered to the circulating pump 24, and part of the concentrated liquid obtained by the nanofiltration membrane group 25 also enters the circulating pump 24. Under the action of the circulating pump 24, the water flow in the nanofiltration membrane system is circulated and treated, and the membrane surface is washed through this circulation of water flow, which can prevent the membrane surface from being blocked by pollutants and ensure the cleanliness of the membrane surface. The circulating pump 24 can adjust the flow and pressure to optimize the flux and life of the membrane. It can also help maintain the appropriate flow rate in the membrane system to improve water permeation and reduce energy consumption.

[0066] The circulating pump 24 inputs the treated water to the nanofiltration membrane group 25, and the water enters the nanofiltration membrane group 25 and is filtered by the nanofiltration membrane. The nanofiltration membrane is the core part of the nanofiltration module, responsible for the actual water treatment process.

[0067] The nanofiltration membrane is made of special polymer material and has a microporous structure, which can retain most of the dissolved substances, bacteria, viruses, heavy metals, pesticide residues and other harmful substances in the water. The separation performance of the nanofiltration membrane is between that of the reverse osmosis membrane and the ultrafiltration membrane, and it can usually remove macromolecular organic matter and divalent and above inorganic salts (such as calcium, magnesium, sulfate, etc.), but allows some monovalent ions (such as sodium, potassium) to pass through. The quality of the nanofiltration membrane directly affects the treatment efficiency and water quality of the entire system.

[0068] In order to provide the efficiency of filtration, a plurality of nanofiltration membranes are arranged in the nanofiltration membrane group 25, and the plurality of nanofiltration membranes are connected in parallel to filter the water to be treated delivered by the circulating pump 24 at the same time.

[0069] In this embodiment, preferably, a first pressure sensor 27 is arranged between the circulating pump 24 and the nanofiltration membrane group 25.

[0070] The nanofiltration membrane needs a certain transmembrane pressure to effectively separate, so the system pressure of the nanofiltration module needs to be monitored. The first pressure sensor 27 is arranged between the circulating pump 24 and the nanofiltration membrane group 25, which can monitor and control the system pressure of the nanofiltration module through the first pressure sensor 27, to ensure the normal operation of the nanofiltration membrane and the treatment efficiency of the nanofiltration membrane.

[0071] In this embodiment, preferably, a second pressure sensor 28 is arranged at the first outlet 252.

[0072] The first outlet 252 outputs the concentrated liquid, part of which can enter the circulating pump 24 together with the water to be treated, and most of which will be transported to the nanofiltration concentrated liquid tank for storage. A second pressure sensor 28 is arranged at the first outlet 252, and by comparing the pressure value detected by the second pressure sensor 28 with the pressure value detected by the first pressure sensor 27, it can be determined whether the working pressure difference of the nanofiltration membrane is normal.

[0073] In this embodiment, preferably, the second outlet 253 is provided with the first flow meter 26.

[0074] The first flow meter 26 arranged at the second outlet 253 is used to monitor the working efficiency of the nanofiltration membrane group 25.

[0075] The performance of the nanofiltration membrane can change over time, and the first flow meter 26 can timely reflect any fluctuation or abnormality of the water flow, helping the staff to find possible membrane pollution or damage. Therefore, the arrangement of the first flow meter 26 helps to effectively evaluate the performance of the nanofiltration membrane and ensure that the system operates in the best working condition.

[0076] In one embodiment, when the value of the first flow meter 26 gradually rises or suddenly rises, the possibility of membrane damage can be considered, and the nanofiltration membrane or the nanofiltration permeate needs to be detected.

[0077] A sewage treatment system, the water treatment system comprises a pretreatment device 4, an anaerobic treatment device 5, a biochemical treatment device 66, an ultrafiltration device 7, a nanofiltration device with a protective membrane function according to any one of claims 1-7, a reverse osmosis device 8 and a DTRO device 9 connected in sequence, the permeate outlet of the ultrafiltration device 7 is connected in communication with the water inlet pipe, and the second outlet 253 is connected in communication with the reverse osmosis device 8.

[0078] The effluent of the pretreatment device 4 is pumped into the anaerobic treatment device 5, and the effluent of the anaerobic treatment device 5 flows into the biochemical system 3. The biochemical system 3, the ultrafiltration device 7, the nanofiltration device 2, the reverse osmosis device 8 and the DTRO device 9 are connected in sequence through pipelines, and the reducing agent dosing device 9 is connected to the front end of the nanofiltration system water inlet pipeline through a pipeline.

[0079] The pretreatment device 4 mainly includes a grid, a coagulation and sedimentation tank, and a regulating tank. After the garbage leachate inflow removes large floating objects and impurities through the grid, it enters the coagulation and sedimentation tank, removes part of the SS and organic matter in the water through dosing and physical sedimentation, and the sedimented permeate overflows into the regulating tank. The leachate is adjusted in water quantity and quality in the regulating tank.

[0080] Anaerobic treatment equipment 5 adopts UASB reactor. The effluent from the pretreatment system is pumped into the anaerobic system, and the leachate is evenly distributed on the bottom of the tank through the anaerobic water distribution system. The leachate passes through the water distribution area, suspended sludge bed and three-phase separator in turn on the tank bottom, reaches the water collection area, and flows into the subsequent treatment system by gravity through the water supply system. Under anaerobic conditions, hydrolytic bacteria, acid-producing bacteria and methanogenic bacteria in the reactor utilize organic pollutants in water for biological activity. The insoluble organic pollutants in water are first decomposed into soluble macromolecular substances, then into small molecular organic acids, and finally into harmless substances such as CO2, CH4 and H2O.

[0081] The biochemical system 3 is composed of two-stage A / O. The effluent from the anaerobic tank flows into the A / O tank group by gravity, and the leachate flows through the denitrification tank and the nitrification tank in turn. Through the nitrification liquid reflux, the residual organic matter, ammonia nitrogen and nitrate nitrogen in the leachate are degraded and removed under the conditions of alternating anoxia and oxygenation.

[0082] The ultrafiltration equipment 7 mainly includes a water inlet pump, a pre-filter, a circulating pump and an ultrafiltration membrane system.

[0083] The pre-filter mainly removes large particle impurities in water to protect the subsequent equipment and the ultrafiltration membrane assembly. The water inlet pump mainly supplies water for the ultrafiltration system. The circulating pump mainly makes the water body circulate continuously to ensure uniform distribution of solutes on the membrane surface, thereby ensuring stable and efficient ultrafiltration process. After the sludge-water mixture of the biochemical system is separated by the ultrafiltration system, the clear liquid enters the nanofiltration membrane system for deep treatment. The concentrated sludge is selected to be returned to the biochemical system or discharged into the sludge tank according to the condition of the biochemical system.

[0084] The nanofiltration equipment 2 mainly includes a water inlet pump, a pre-filter, a high-pressure pump, a circulating pump and a nanofiltration membrane system. The pre-filter mainly removes large particle impurities in water to protect the subsequent equipment and the nanofiltration membrane assembly. The water inlet pump mainly supplies water for the nanofiltration system. The high-pressure pump provides high pressure for the nanofiltration membrane to separate impurities and solutes in water under a certain water pressure difference. The nanofiltration circulating pump mainly provides power for the nanofiltration system to overcome the resistance loss in the system and ensure the smooth progress of the nanofiltration process. The nanofiltration system can further remove macromolecular organic matter, heavy metals and high-valence ions in the ultrafiltration effluent, and also plays a good pretreatment role for the subsequent reverse osmosis treatment, effectively avoiding scaling and blockage of reverse osmosis. The clear liquid from the nanofiltration system enters the reverse osmosis system, and the concentrated liquid enters the DTRO raw water tank.

[0085] The reverse osmosis equipment 8 mainly comprises a water inlet pump, a security filter, a high-pressure pump, a circulating pump and a reverse osmosis membrane system. The security filter can intercept particulate impurities, prevent membrane pollution and mechanical damage, protect the reverse osmosis membrane from microbial invasion, ensure the effectiveness of the addition of reagents, and maintain stable operation of the system and prolong the service life; the water inlet pump mainly supplies water for the reverse osmosis system, the high-pressure pump provides the necessary pressure for the reverse osmosis system to ensure that the water flow can effectively pass through the reverse osmosis membrane, thereby realizing water purification, and the main function of the reverse osmosis circulating pump is to circulate the treated liquid back to the front end of the reverse osmosis membrane to ensure water production efficiency and water quality purity, and the circulating pump can also reduce the pressure loss of the reverse osmosis membrane, avoiding excessive compression damage to the reverse osmosis membrane. The treated water of the nanofiltration system is further treated by the reverse osmosis system to remove almost all monovalent ions, inorganic salts, molecules, organic colloids, bacteria and pathogens in the water. Ensure that CODcr, ammonia nitrogen, total nitrogen, heavy metal ions and other indicators in the effluent meet the requirements of the reclaimed water standard, and the clear liquid of the reverse osmosis system flows into the clear water tank for reuse, and the concentrated liquid enters the DTRO raw water tank.

[0086] The DTRO equipment 9 mainly comprises a water inlet pump, a security filter, a high-pressure piston pump, a circulating pump and a DTRO membrane system. The security filter mainly removes impurities, protects downstream equipment and ensures stable operation of the system, the water inlet pump mainly supplies water for the DTRO system, the high-pressure piston pump mainly provides high-pressure water flow for the DTRO membrane, and the main function of the DTRO circulating pump is to provide sufficient flow and flow rate for the membrane assembly to ensure the cleanliness and efficient operation of the membrane surface. In the DTRO membrane column, the concentration of the raw water gradually increases as the percolate flows through the surface of the membrane, and other substances in the water are left on the concentrated water side of the membrane, and the concentrated liquid is discharged into the factory yard, and the pure water that passes through the membrane is called "permeate" and flows into the clear water tank for reuse.

[0087] The ORP meter 1 is installed between the ultrafiltration equipment 7 and the nanofiltration equipment 2; the ORP meter 1 is used to detect the oxidation-reduction potential of the nanofiltration system inlet water; the ORP meter 1 is installed at the front end of the nanofiltration system inlet water to detect the oxidation-reduction potential, when the content of oxidizing substances in the nanofiltration system inlet water is qualified, the water treatment equipment operates normally, when the content of oxidizing substances in the nanofiltration system inlet water is too high, the ORP meter 1 display value will increase, when the ORP meter 1 display value exceeds the control set value, the reducing agent adding part 3 is started to add reducing agent to react with the oxidizing substances in the water to remove the oxidizing substances in the water.

[0088] The ORP meter has a range of -2000mv to 2000mv. Preferably, the limit value of the ORP meter 1 is set to 300mv, when the measured value of the ORP meter 1 is lower than 300mv, the nanofiltration membrane is not easy to be oxidized.

[0089] In this embodiment, preferably, the ultrafiltration equipment 7 comprises a chlorine adding part, the chlorine adding part is provided with a second meter, and the second meter is electrically connected with the first meter.

[0090] The ultrafiltration device 7 includes a chlorine adding part, and the chlorine added by the ultrafiltration device 7 will remain in the water, so the first meter must be opened to add a reducing agent to the water. The amount of the reducing agent added by the first meter can be determined according to the amount of chlorine added by the second meter.

[0091] In this embodiment, the ORP meter 1 is preferably arranged behind the reducing agent adding part 3.

[0092] The amount of the reducing agent added by the first meter according to the second meter cannot always complete the reduction of the residual chlorine in the water due to the influence of time, temperature and other factors, so the ORP meter 1 is also needed to monitor the oxidation-reduction potential of the water after the addition of the reducing agent, and if the oxidation-reduction potential is found to exceed the control setting value, the amount of the reducing agent added by the first meter needs to be increased.

[0093] Therefore, in the sewage treatment system, the amount added by the second meter determines the basic amount added by the first meter, and the monitoring result of the ORP meter 1 can fine-tune the basic amount added by the first meter. If it is detected that the oxidation in the water is still higher than the setting value, the amount of the reducing agent added by the first meter can be appropriately increased, and if it is found that the water generally shows strong reducing property, the ORP meter 1 can control the first meter to appropriately reduce the amount of the reducing agent added.

[0094] The preferred embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0095] In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combination manners.

[0096] In addition, various different embodiments of the present application can also be combined in any manner, as long as they do not deviate from the idea of the present application, and they should also be considered as disclosed by the present application.

Claims

1. A nanofiltration apparatus having a protective membrane function, characterized by comprising: The nanofiltration equipment with the protective film function comprises a water inlet pipe, an ORP meter (1), a nanofiltration module and a reducing agent adding part (3), the water inlet pipe is communicated with the nanofiltration module for inputting water to be treated into the nanofiltration module, the ORP meter (1) is arranged on the water inlet pipe, the ORP meter (1) is located at the front end of the nanofiltration module, the reducing agent adding part (3) is communicated with the water inlet pipe, and the ORP meter (1) is electrically connected with the reducing agent adding part (3). The ORP meter (1) detects the oxidation-reduction potential in the water inlet pipe of the nanofiltration module, and the ORP meter (1) controls the reducing agent adding part (3).

2. The nanofiltration apparatus with a protective membrane function according to claim 1, characterized by, The ORP meter (1) is provided with a control set value, when the value detected by the ORP meter (1) is higher than the control set value, the ORP meter (1) controls the reducing agent adding part (3) to be opened.

3. The nanofiltration apparatus with a protective membrane function according to claim 2, characterized by, The reducing agent adding part (3) comprises a first meter, which controls the adding amount of the reducing agent.

4. The nanofiltration apparatus having a protective film function according to claim 1, wherein, The nanofiltration module comprises a water inlet pump (21), a pre-filter (22), a high-pressure water pump (23), a circulating pump (24) and a nanofiltration membrane group (25), the water inlet pump (21) is arranged on the water inlet pipe and located at the front end of the pre-filter (22), one end of the high-pressure water pump (23) is connected with the outlet of the pre-filter (22), the other end is communicated with the first inlet (241) of the circulating pump (24), the outlet of the circulating pump (24) is communicated with the second inlet (251) of the nanofiltration membrane group (25), the first outlet (252) of the nanofiltration membrane group (25) is communicated with the first inlet (241), and the second outlet (253) of the nanofiltration module outputs clean liquid.

5. The nanofiltration apparatus having a protective film function according to claim 4, characterized by, A first pressure sensor (27) is arranged between the circulating pump (24) and the nanofiltration membrane group (25).

6. The nanofiltration apparatus having a protective film function according to claim 5, wherein, A second pressure sensor (28) is arranged at the first outlet (252).

7. The nanofiltration apparatus having a protective film function according to claim 6, wherein, A first flow meter (26) is arranged at the position of the second outlet (253).

8. A sewage treatment system characterised in that, The sewage treatment system comprises a pretreatment equipment (4), an anaerobic treatment equipment (5), a biochemical treatment equipment (6), an ultrafiltration equipment (7), the nanofiltration equipment with the protective film function according to any one of claims 1-7, a reverse osmosis equipment (8) and a DTRO equipment (9) which are connected in sequence, the clean liquid outlet of the ultrafiltration equipment (7) is communicated with the water inlet pipe, and the second outlet (253) is communicated with the reverse osmosis equipment (8). The ultrafiltration equipment (7) comprises a chlorination part, the chlorination part is provided with a second meter, and the second meter is electrically connected with the first meter.

9. The sewage treatment system of claim 8, wherein, The ORP meter (1) is arranged behind the reducing agent adding part (3).

10. The sewage treatment system of claim 9, wherein, ​

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