A membrane protection system in a landfill leachate treatment system
The reducing agent dosing system, controlled by an ORP meter and PLC module, solves the problem of nanofiltration reverse osmosis membranes being sensitive to residual chlorine, extends membrane lifespan, optimizes dosing control, and reduces production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAN PANHONG TECHNOLOGY CO LTD
- Filing Date
- 2025-07-16
- Publication Date
- 2026-06-26
AI Technical Summary
Existing nanofiltration and reverse osmosis membrane systems have poor tolerance to oxidizing substances such as residual chlorine, leading to membrane perforation and structural damage. Furthermore, the dosage of chemicals is difficult to control, affecting membrane life and production costs.
The oxidation-reduction potential of the nanofiltration system feed water is detected by an ORP meter. The reducing agent dosing device is controlled by a PLC module to automatically adjust the dosage of reducing agent in order to remove oxidizing substances in the water and protect the nanofiltration and reverse osmosis membranes.
It effectively prevents oxidation and perforation of nanofiltration and reverse osmosis membranes, extends membrane lifespan, increases system water production, enables precise control of chemical dosage, and reduces production and maintenance costs.
Smart Images
Figure CN224411581U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of wastewater treatment technology, specifically to a membrane protection system in a landfill leachate treatment system. Background Technology
[0002] Membrane technology has been developing for nearly 70 years since the 1950s. Nanofiltration and reverse osmosis are essential membrane technologies for deep desalination in water treatment, with a wide range of applications, from seawater desalination to industrial wastewater treatment. Their high precision and stability make nanofiltration and reverse osmosis membranes irreplaceable in ensuring water quality and reducing energy consumption and emissions. However, due to their high-precision manufacturing process, complex membrane materials and structures, import tariffs, and supply chain issues, their prices are high. In daily production, how to improve the lifespan of nanofiltration and reverse osmosis membranes while meeting water production requirements has become a concern for most users.
[0003] Currently available nanofiltration and reverse osmosis membranes have a certain degree of tolerance to acids and alkalis, but their tolerance to oxidizing substances such as residual chlorine is very poor. For example, the composite structure of a reverse osmosis membrane consists of a bottom layer of approximately 120μm thick polyester-reinforced nonwoven fabric, a middle layer of approximately 40μm thick porous polysulfone intermediate support layer ensuring sufficient water permeability for reverse osmosis, and an outermost, thinnest layer of approximately 0.2μm polyamide ultrathin separation layer. This thinnest layer provides the most crucial desalination and separation performance. However, the polyamide ultrathin separation layer is particularly sensitive to residual chlorine. The strong oxidizing properties of residual chlorine can cause membrane perforation and damage to the membrane structure. Simultaneously, residual chlorine lowers the redox potential in the water, accelerating the reaction of pollutants with the membrane. Residual chlorine adheres to and forms fouling on the membrane, leading to a decline in water quality. It can also react chemically with the reverse osmosis membrane material, causing degradation and reducing desalination efficiency and lifespan. Therefore, removing residual chlorine and other oxidizing substances from the incoming water is crucial for improving the permeate and desalination rates of reverse osmosis membranes and extending their lifespan. Typically, reducing agents are added upstream of the membrane equipment to break down residual chlorine and other oxidizing substances. However, in practice, the quality of incoming water varies greatly, and the content of oxidizing substances changes significantly with the composition of the incoming water and seasonal temperature. This makes it very difficult to control the dosage of reducing agent during dosing. Adding too little will not protect the membrane, while adding too much will increase the operating burden on the membrane equipment due to excessive inorganic substances. Utility Model Content
[0004] Therefore, it is necessary to provide a membrane protection system to address the problems of excessively high or low residual chlorine and other oxidizing substances in the feed water of existing nanofiltration and reverse osmosis systems, which can lead to perforation and damage of nanofiltration and reverse osmosis membranes and difficulty in controlling the dosage of chemicals. This system would prevent nanofiltration and reverse osmosis membrane modules from being oxidized and perforated, thus preventing damage to the membrane structure, improving the service life of nanofiltration and reverse osmosis membrane modules, and saving production costs.
[0005] To solve the above-mentioned technical problems, this utility model provides a membrane protection system in a landfill leachate treatment system.
[0006] This utility model discloses a membrane protection system in a landfill leachate treatment system, comprising a pretreatment system, an anaerobic system, a biochemical system, an ultrafiltration system, a nanofiltration system, a reverse osmosis system, a DTRO system, and a membrane protection system.
[0007] The effluent from the pretreatment system is pumped into the anaerobic system, and the effluent from the anaerobic system flows by gravity into the biological system. The biological system, ultrafiltration system, membrane protection system, nanofiltration system, reverse osmosis system, and DTRO system are connected in sequence through pipelines. The membrane protection system consists of an ORP meter, a reducing agent dosing device, and a PLC module.
[0008] The membrane protection system in the landfill leachate treatment system is electrically connected to an ORP meter, a reducing agent dosing device, and a PLC module. The ORP meter's detection data is uploaded to the PLC module, which controls the start and stop of the reducing agent dosing device based on the ORP meter data. When the content of oxidizing substances in the nanofiltration system influent is too high, the ORP meter reading will increase. When the ORP meter reading exceeds a certain limit, the PLC module controls the reducing agent dosing device to start. When the content of oxidizing substances in the nanofiltration system influent is low, the ORP meter reading will decrease. When the ORP meter reading is below a certain limit, the reducing agent dosing device will be shut down.
[0009] The membrane protection system in the landfill leachate treatment system includes an ORP meter to detect the oxidation-reduction value at the inlet of the nanofiltration system, and a reducing agent dosing device to add chemicals to the nanofiltration inlet pipe.
[0010] The membrane protection system in the landfill leachate treatment system has preset limits of 100mV and 300mV for the ORP meter, and the range of the ORP meter is -2000mV to 2000mV.
[0011] The membrane protection system in the landfill leachate treatment system is described above, and the reducing agent dosing device is equipped with a frequency converter to control the dosing amount.
[0012] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0013] This invention relates to a membrane protection system in a landfill leachate treatment system. The membrane protection system includes an ORP meter, a reducing agent dosing device, and a PLC module. The ORP meter is used to detect the oxidation-reduction potential of the nanofiltration system's influent. When the content of oxidizing substances in the nanofiltration system's influent is too high, the ORP meter reading will increase. When the value uploaded to the PLC exceeds the limit of 300mV, the reducing agent dosing device is activated; when it is below the limit of 100mV, the reducing agent dosing device is deactivated. The reducing agent will undergo an oxidation-reduction reaction with residual chlorine and other oxidizing substances in the water, removing the oxidizing substances and preventing the nanofiltration membrane and subsequent reverse osmosis and DTRO membranes from being oxidized and perforated. This improves the service life of the nanofiltration membrane, reverse osmosis membrane, and DTRO membrane, increases the system's water production, and enables automatic control of the dosing of chemicals, effectively controlling the dosage and reducing subsequent production and maintenance costs. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of a membrane protection system in a landfill leachate treatment system according to an embodiment of the present invention.
[0015] Figure 2 This is a schematic diagram illustrating the working principle of the membrane protection system described in this embodiment of the present invention.
[0016] In the picture:
[0017] 1. Pretreatment system; 2. Anaerobic system; 3. Biochemical system; 4. Ultrafiltration system; 5. Nanofiltration system; 6. Reverse osmosis system; 7. DTRO system; 8. ORP meter; 9. Reducing agent dosing device; 10. Membrane protection system; 11. PLC module. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the membrane protection device in the landfill leachate treatment system of this utility model will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining this utility model and are not intended to limit this utility model.
[0019] See Figure 1 This utility model provides a membrane protection system in a landfill leachate treatment system, including a pretreatment system 1, an anaerobic system 2, a biochemical system 3, an ultrafiltration system 4, a nanofiltration system 5, a reverse osmosis system 6, a DTRO system 7, and a membrane protection system 10.
[0020] In this utility model, the effluent from the pretreatment system 1 is pumped into the anaerobic system 2, and the effluent from the anaerobic system 2 flows by gravity into the biochemical system 3. The biochemical system 3, ultrafiltration system 4, nanofiltration system 5, reverse osmosis system 6, and DTRO system 7 are connected in sequence through pipelines, and the membrane protection system 10 is connected to the front end of the nanofiltration system inlet pipeline through a pipeline.
[0021] The pretreatment system 1 mainly includes structures such as a screen, coagulation sedimentation tank, and equalization tank. After the landfill leachate water passes through the screen to remove large floating objects and impurities, it enters the coagulation sedimentation tank. Through chemical dosing and physical sedimentation, some of the suspended solids (SS) and organic matter in the water are removed. The clear liquid after sedimentation overflows into the equalization tank, where the leachate is used to adjust the water quantity and quality.
[0022] Anaerobic System 2 employs a UASB reactor. Pretreatment system effluent is pumped into the anaerobic system, where it is evenly distributed at the bottom of the tank via an anaerobic distribution system. The leachate then sequentially passes through the distribution zone, suspended sludge bed, and three-phase separator before reaching the collection zone. From there, it flows by gravity into the subsequent treatment system via the feedwater system. Under anaerobic conditions, hydrolytic bacteria, acid-producing bacteria, and methanogenic bacteria within the reactor utilize organic pollutants in the water for biological activity. The sparingly soluble organic pollutants are first decomposed into soluble macromolecules, then into smaller organic acids, and finally into harmless substances such as CO2, CH4, and H2O.
[0023] Biological system 3 consists of two-stage A / O. The effluent from the anaerobic tank flows by gravity into the A / O tank group, and the leachate flows sequentially through the denitrification tank and the nitrification tank. Through the nitrification liquid recirculation, under alternating anoxic and aerobic conditions, the remaining organic matter, ammonia nitrogen, and nitrate nitrogen in the leachate are degraded and removed.
[0024] The ultrafiltration system 4 mainly includes an inlet pump, a pre-filter, a circulation pump, and an ultrafiltration membrane system.
[0025] The pre-filter mainly removes large particulate impurities from the water, protecting downstream equipment and ultrafiltration membrane modules. The feed pump mainly supplies water to the ultrafiltration system, while the circulation pump mainly circulates the water continuously, ensuring the uniform distribution of solutes on the membrane surface, thereby guaranteeing the stability and efficiency of the ultrafiltration process. After the sludge-water mixture of the biological system is separated by the ultrafiltration system, the clarified liquid enters the nanofiltration membrane system for further treatment. The concentrated sludge is either returned to the biological system or discharged into the sludge tank, depending on the condition of the biological system.
[0026] The nanofiltration system mainly consists of an inlet pump, a pre-filter, a high-pressure pump, a circulation pump, and a nanofiltration membrane system. The pre-filter primarily removes large particulate impurities from the water, protecting downstream equipment and the nanofiltration membrane module. The inlet pump supplies water to the nanofiltration system. The high-pressure pump provides high pressure to the nanofiltration membrane, separating impurities and solutes under a certain pressure difference. The nanofiltration circulation pump provides power to the nanofiltration system, overcoming resistance losses within the system and ensuring smooth nanofiltration. The nanofiltration system further removes large molecular organic matter, heavy metals, and high-valence ions from the ultrafiltration water, while also providing excellent pretreatment for subsequent reverse osmosis treatment, effectively preventing scaling and fouling in the reverse osmosis system. The clarified solution from the nanofiltration system enters the reverse osmosis system, while the concentrated solution enters the DTRO raw water tank.
[0027] The reverse osmosis system mainly includes a feed pump, a security filter, a high-pressure pump, a circulation pump, and a reverse osmosis membrane system. The security filter intercepts particulate impurities, prevents membrane fouling and mechanical damage, protects the reverse osmosis membrane from microbial attack, ensures the effectiveness of reagent addition, and maintains stable system operation and extends its lifespan. The feed pump primarily supplies water to the reverse osmosis system, while the high-pressure pump provides the necessary pressure to ensure water flow effectively through the reverse osmosis membrane, thus purifying the water. The main function of the reverse osmosis circulation pump is to circulate the treated solution back to the front end of the reverse osmosis membrane to ensure water production efficiency and water purity. The circulation pump also reduces pressure loss from the reverse osmosis membrane, preventing excessive compression and damage. The effluent from the nanofiltration system is further treated by the reverse osmosis system, removing almost all monovalent ions, inorganic salts, molecules, organic colloids, bacteria, pathogens, etc., ensuring that CODcr, ammonia nitrogen, total nitrogen, and heavy metal ions in the effluent meet reuse water standards. The clarified solution from the reverse osmosis system flows into the clear water tank for reuse, while the concentrated solution enters the DTRO raw water tank.
[0028] The DTRO system mainly includes a feed pump, a security filter, a high-pressure plunger pump, a circulation pump, and a DTRO membrane system. The security filter primarily removes impurities, protects downstream equipment, and ensures stable system operation. The feed pump mainly supplies water to the DTRO system. The high-pressure plunger pump mainly provides high-pressure water flow to the DTRO membrane. The main function of the DTRO circulation pump is to provide sufficient flow rate and velocity to the membrane modules, ensuring the cleanliness and efficient operation of the membrane surface. In the DTRO membrane column, as the permeate flows across the membrane surface, the concentration of the raw water gradually increases. Other substances in the water are retained on the concentrate side of the membrane. The concentrate is discharged into the plant storage area, while the pure water that permeates through the membrane, known as "permeate," flows into the clear water tank for reuse.
[0029] See Figure 2 The membrane protection system 10 includes an ORP meter 8, a reducing agent dosing device 9, and a PLC module 11. The ORP meter 8 is used to detect the oxidation-reduction potential of the nanofiltration system's influent. When the content of oxidizing substances in the nanofiltration system's influent is within acceptable limits, the water treatment equipment operates normally. When the content of oxidizing substances in the nanofiltration system's influent is too high, the ORP meter 8's detection value will increase. When the ORP meter 8's detection value exceeds the limit of 300mV, the reducing agent dosing device 9 is activated, adding reducing agent to react with the oxidizing substances in the water to remove them. The amount of agent added depends on the difference between the detection value uploaded to the PLC module 11 and 300mV. When the amount of oxidizing substances in the water is low, and the ORP meter 8's detection value is below 100mV, the reducing agent dosing device 9 stops adding agents. This allows for control of the dosing amount based on the incoming water conditions, saving on dosing costs.
[0030] As one possible implementation, the range of the ORP meter 8 is -2000mv to 2000mv. The preset limits of the ORP meter are 100mv and 300mv. When the measured value of the ORP meter 8 is lower than 100mv, the nanofiltration and reverse osmosis membranes are not easily oxidized. When the measured value of the ORP meter 8 is higher than 300mv, a reducing agent needs to be added.
[0031] As one possible implementation, the PLC module 11 is connected to a frequency converter to control the dosage. The more the ORP meter 8 measures a value greater than 300mV, the greater the dosage of reducing agent.
[0032] The embodiments described above are merely illustrative of the implementation of this utility model, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.
Claims
1. A membrane protection system in a landfill leachate treatment system, comprising a pretreatment system (1), an anaerobic system (2), a biochemical system (3), an ultrafiltration system (4), a nanofiltration system (5), a reverse osmosis system (6), a DTRO system (7), and a membrane protection system (10), characterized in that... The effluent from the pretreatment system (1) is pumped into the anaerobic system (2), and the effluent from the anaerobic system (2) flows by gravity into the biochemical system (3). The biochemical system (3), ultrafiltration system (4), membrane protection system (10), nanofiltration system (5), reverse osmosis system (6), and DTRO system (7) are connected by pipelines. The membrane protection system (10) consists of an ORP meter (8), a reducing agent dosing device (9), and a PLC module (11).
2. The membrane protection system in a landfill leachate treatment system according to claim 1, characterized in that: The ORP meter (8), reducing agent dosing device (9) and PLC module (11) in the membrane protection system are electrically connected. The detection data of the ORP meter (8) is uploaded to the PLC module (11), and the PLC module (11) controls the start and stop of the reducing agent dosing device (9) according to the data of the ORP meter (8).
3. The membrane protection system in a landfill leachate treatment system according to claim 1, characterized in that: ORP meter (8) detects the oxidation-reduction value at the inlet of nanofiltration system (5), and reducing agent dosing device (9) adds the agent to the nanofiltration inlet pipe.
4. A membrane protection system in a landfill leachate treatment system according to claim 1, 2, or 3, characterized in that: The preset limit values of the ORP meter (8) are 100mv and 300mv, and the range of the ORP meter (8) is -2000mv to 2000mv.
5. The membrane protection system in a landfill leachate treatment system according to claim 1, characterized in that: The membrane protection system (10) is equipped with a frequency converter to control the dosage.