Microplastic ultrafiltration removal system

Abstract

The utility model belongs to water treatment technical field, and it is a kind of microplastic ultrafiltration removal system, provide a kind of microplastic ultrafiltration removal system, including filter system and control backwashing system, the filter system includes raw water tank, microplastic analysis device, chlorination device, ultrafiltration membrane system, water inlet valve group, activated carbon column, water production tank, water production valve and PLC control system, the control backwashing system includes backwash pump, backwash inlet valve, backwash discharge valve and wastewater tank, the utility model has the beneficial effects that: one, precision interception and membrane pollution control, two, energy consumption and operation cost optimization, three, safety and reliability improvement, four, intelligent operation and maintenance advantage.

Description

Technical Field

[0001] This utility model belongs to the field of water treatment technology, specifically relating to a microplastic ultrafiltration removal system. Background Technology

[0002] With the widespread use of plastic products, microplastic pollution is becoming increasingly serious, posing a potential threat to the ecological environment and human health. Traditional wastewater treatment processes have limited effectiveness in removing microplastics; therefore, developing efficient and economical microplastic removal technologies is of great significance. Ultrafiltration technology is widely used in water treatment due to its advantages of simple operation and high removal efficiency. However, traditional ultrafiltration systems have the following problems when treating water containing microplastics:

[0003] (1) Severe membrane fouling: Microplastics easily clog the pores of ultrafiltration membranes, leading to increased membrane fouling and higher operating costs.

[0004] (2) Low operating efficiency: Traditional ultrafiltration systems usually operate at a constant flow rate and cannot be optimized according to changes in water quality, resulting in energy waste.

[0005] (3) Lack of real-time monitoring: It is impossible to monitor the type, particle size and content of microplastics in real time, making it difficult to achieve precise control.

[0006] (4) Risk of chlorination degradation of microplastics: In order to control microbial contamination, chlorination is often performed before ultrafiltration. However, excessive chlorine may degrade larger microplastics into smaller microplastics, which will increase the difficulty of removal. Utility Model Content

[0007] The purpose of this invention is to address the problems of severe membrane fouling, low operating efficiency, lack of real-time monitoring, and risk of chlorination degradation of microplastics in traditional ultrafiltration systems when treating water containing microplastics, and to provide a microplastic ultrafiltration removal system.

[0008] A microplastic ultrafiltration removal system includes a filtration system and a backwash control system;

[0009] The filtration system includes a raw water tank 1, a microplastic analysis device 2, a chlorination device 3, an ultrafiltration membrane system 4, an inlet valve group 5, an activated carbon column 6, a product water tank 7, a product water valve 13, and a PLC control system 17.

[0010] The ultrafiltration membrane system 4 consists of multiple parallel ultrafiltration membrane modules. Each membrane module is equipped with an independent water inlet pipe and a water inlet valve. Multiple water inlet valves form a water inlet valve group 5, which controls the operating status of each membrane module.

[0011] The microplastic analysis device 2 is connected to the raw water tank 1. The outlet pipe of the raw water tank 1 is connected to the outlet pipe of the chlorination device 3 and multiple inlet pipes of the ultrafiltration membrane system 4. Multiple product water outlets of the ultrafiltration membrane system 4 are connected to the inlet pipe of the activated carbon column 6 through water pipes. The outlet pipe of the activated carbon column 6 is connected to the product water tank 7.

[0012] The backwash control system includes a backwash pump 14, a backwash inlet valve 15, a backwash outlet valve 16, and a wastewater tank 8; the outlet pipe of the product water tank 7 is connected to the product water port of the ultrafiltration membrane system 4 through the backwash pump 14 and the backwash valve 15, and the concentrate port of the ultrafiltration membrane system 4 is connected to the wastewater tank 8 through a water pipe and the backwash outlet valve 16.

[0013] The PLC control system 17 is connected to and controls the microplastic analysis device 2, the chlorination device 3, the inlet valve group 5, the backwash pump 14, and the backwash inlet valve 15.

[0014] The microplastic analysis device 2 used in this invention is an integrated and innovative device, whose core components are all integrated using commercially available standard sensor modules, including:

[0015] ① Infrared spectral sensor (model such as ThermoFisher Nicolet iS5, used for microplastic identification, detection wavelength range 7800-350cm) -1 (Connects to the PLC analog input module via a 4-20mA analog signal; used for microplastic type identification);

[0016] ② Laser particle size sensor (e.g., Malvern Mastersizer 3000, used for particle size distribution detection, range 0.01-3500μm); uses Modbus RTU protocol to communicate with PLC via RS485 bus; used for particle size distribution detection;

[0017] ③ Mass flow sensor (model such as Siemens SITRANSFC430, used for quantitative analysis of content, measurement accuracy ±0.5%); three-wire connection (brown wire to 24VDC positive terminal, blue wire to common terminal, black signal wire to PLC digital input channel); used for quantitative analysis of content;

[0018] ④ Image acquisition module (using a Baslerace series industrial camera with a resolution ≥ 5 megapixels, and morphological analysis using the OpenCV open-source library); fixed via a C-Mount industrial lens mount; performing morphological analysis. The infrared spectral sensor, laser particle size sensor, mass flow sensor, and image acquisition module are all existing devices and technologies.

[0019] The PLC control system 17 used in this utility model is an industrial-grade PLC controller, selected as follows:

[0020] Siemens S7-1200 series (model: 6ES7214-1HG40-0XB0) or Mitsubishi Electric FX5U-32MT / ES series; PLC control system 17 has been widely used in the water treatment field, and features: multi-channel analog input (supports 4-20mA sensor signal access), industrial Ethernet communication protocol (Modbus TCP / IP), and fuzzy control algorithm module (for dynamically adjusting ultrafiltration parameters).

[0021] The principle of this utility model:

[0022] I. The microplastic analysis device 2 in this utility model is used to monitor the type, particle size, and content of microplastics in raw water in real time, and transmits the data to the PLC control system 17; the PLC control system 17 receives the data from the microplastic analysis device 2 and controls it according to the following strategy:

[0023] (1) Chlorination control: When the microplastic particle size is less than 0.05μm, the PLC control system 17 controls the amount of chlorination added by the chlorination device 3 so that it is not degraded to the point that the particle size is too small (meaning that the particle size after microplastic degradation is not less than the average pore size of the membrane), so that it is not intercepted by the ultrafiltration membrane system 4; the specific control strategy can be: when the microplastic particle size is less than the set threshold (set to 1.0-1.5 times the average pore size of the ultrafiltration membrane), reduce the amount of chlorination or stop chlorination;

[0024] (2) Membrane module operation control: Based on the type, particle size, and content of microplastics, the PLC control system 17 flexibly adjusts the number of membrane modules participating in filtration, thereby adjusting the effective filtration area to achieve energy saving, reduce membrane fouling, and extend membrane lifespan; specific control strategies may include:

[0025] ① When the microplastic content is low, the number of membrane modules in operation can be reduced, the operating cost can be lowered, and the operating load of a single membrane module can be increased, which is beneficial to the self-cleaning of the membrane.

[0026] ② When the microplastic content is high, increase the number of operating membrane modules to increase the effective filtration area, reduce the operating load on the membrane, and slow down membrane fouling;

[0027] ③ When the microplastic particle size is greater than 10μm, the number of membrane modules in operation can be increased to ensure sufficient filtration capacity;

[0028] ④ When there are many types of microplastics, appropriate membrane modules can be selected for filtration based on the characteristics of different types of microplastics;

[0029] (3) Backwashing control: The PLC control system 17 controls the frequency and intensity of the backwashing system (including backwash pump 14 and backwash inlet valve 15) according to the water quality and filtration conditions; the specific control strategy may be: when the membrane pressure difference rises to the set threshold (set to 1.5-2.0 times the initial operating pressure difference), backwashing is started; the backwashing frequency and intensity are adjusted according to the rate of increase of the membrane pressure difference.

[0030] II. Activated carbon column 6 is used to adsorb residual organic matter and chlorine in the ultrafiltration effluent;

[0031] Third, the early warning system 9 is connected to the outlet pipe of the activated carbon column 6 to monitor the status of microplastics, residual chlorine and secondary pollutants in the water in real time, and transmits the data to the PLC control system 17. When an excessive level is detected, an alarm is issued.

[0032] The beneficial effects of this utility model are:

[0033] I. Precise Retention and Membrane Fouling Control:

[0034] (1) Improved microplastic removal rate: Through particle size-chlorination amount feedforward control and dynamic membrane area adjustment (matching the pollution load), the overall microplastic removal rate is ≥99.8%;

[0035] (2) Reduced membrane fouling rate: The PLC control system 17 reduces the fluctuation range of single membrane flux to ±15%, reduces the membrane fouling rate by 40%-50%, and extends the chemical cleaning cycle.

[0036] (3) Backwashing efficiency optimization: The graded backwashing strategy (graded backwashing refers to gradually increasing the intensity of backwashing during the backwashing process to more effectively remove contaminants from the membrane surface; graded backwashing can be achieved through pressure grading, flow grading, time grading or combined grading; for example, backwashing can be performed at a lower pressure for a period of time, and then the pressure can be gradually increased, with each increase in pressure followed by a period of time; the PLC control system 17 can automatically select a suitable graded backwashing scheme and optimize backwashing parameters based on parameters such as membrane pressure difference and raw water quality) reduces the number of ineffective backwashings, and reduces backwashing water consumption by 35%-50%;

[0037] II. Energy consumption and operating cost optimization:

[0038] (1) Dynamic energy consumption matching: By dynamically adjusting the number of membrane modules (N=1-4 modules), under low load conditions (processing capacity <50m³), 3 The system energy consumption is reduced by 25%-35% under ( / h);

[0039] (2) Reduced reagent consumption: Intelligent control of chlorine dosage reduces chlorine dosage by 20%-30%;

[0040] (3) Extended membrane life: The membrane fouling uniformity design (alternating operation + flux balance control) extends the service life of the membrane module;

[0041] III. Enhanced Security and Reliability:

[0042] (1) Dual retention guarantee: The ultrafiltration membrane system 4 (retains particles ≥0.01μm) and the activated carbon column 6 (adsorbs nanoplastics <0.01μm) work together to ensure a low concentration of microplastics in the effluent;

[0043] (2) Real-time early warning response: The early warning system 9 has a response time of ≤30 seconds to microplastic leakage and excessive residual chlorine or disinfection by-product content. The linkage control can quickly restore water quality to meet the standards.

[0044] (3) Fault tolerance: The four-membrane parallel structure allows the other three groups to automatically increase the flux by 20% to maintain operation when a single group is offline for maintenance, resulting in high system availability;

[0045] IV. Advantages of Intelligent Operation and Maintenance:

[0046] (1) Process parameter self-learning: The PLC control system 17 optimizes the control model by training with historical data (such as dynamic adjustment of backwash trigger threshold), so that the operating efficiency increases by 10%-15% with the use time;

[0047] (2) Reduced manual intervention: Full-process automated control greatly reduces the frequency of manual inspections and reduces operation and maintenance costs;

[0048] (3) Data traceability: The system automatically generates key reports such as microplastic concentration distribution map and membrane fouling trend curve, providing data support for process optimization. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the structure of a microplastic ultrafiltration removal system as described in Example 1. Detailed Implementation

[0050] Specific Implementation Method 1: This implementation method provides a microplastic ultrafiltration removal system, which includes a filtration system and a backwashing control system.

[0051] The filtration system includes a raw water tank 1, a microplastic analysis device 2, a chlorination device 3, an ultrafiltration membrane system 4, an inlet valve group 5, an activated carbon column 6, a product water tank 7, a product water valve 13, and a PLC control system 17.

[0052] The ultrafiltration membrane system 4 consists of multiple parallel ultrafiltration membrane modules. Each membrane module is equipped with an independent water inlet pipe and a water inlet valve. Multiple water inlet valves form a water inlet valve group 5, which controls the operating status of each membrane module.

[0053] The microplastic analysis device 2 is connected to the raw water tank 1. The outlet pipe of the raw water tank 1 is connected to the outlet pipe of the chlorination device 3 and multiple inlet pipes of the ultrafiltration membrane system 4. Multiple product water outlets of the ultrafiltration membrane system 4 are connected to the inlet pipe of the activated carbon column 6 through water pipes. The outlet pipe of the activated carbon column 6 is connected to the product water tank 7.

[0054] The backwash control system includes a backwash pump 14, a backwash inlet valve 15, a backwash outlet valve 16, and a wastewater tank 8; the outlet pipe of the product water tank 7 is connected to the product water port of the ultrafiltration membrane system 4 through the backwash pump 14 and the backwash valve 15, and the concentrate port of the ultrafiltration membrane system 4 is connected to the wastewater tank 8 through a water pipe and the backwash outlet valve 16.

[0055] The PLC control system 17 is connected to and controls the microplastic analysis device 2, the chlorination device 3, the inlet valve group 5, the backwash pump 14, and the backwash inlet valve 15.

[0056] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the ultrafiltration membrane system 4 consists of four parallel ultrafiltration membrane modules. Each membrane module has an independent inlet pipe with an inlet valve. The four inlet valves form an inlet valve group 5, which controls the operating status of each membrane module. Other steps are the same as in Specific Implementation Method One.

[0057] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: a raw water pump 10 is installed on the outlet pipe of the raw water tank 1. The other steps are the same as in Specific Implementation Method One or Two.

[0058] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the outlet pipe of the raw water tank 1 is equipped with an inlet valve 11. The other steps are the same as in Specific Implementation Methods One to Three.

[0059] Specific Implementation Method 5: This implementation method differs from Specific Implementation Methods 1 to 4 in that: a chlorination valve 12 is installed on the outlet pipe of the chlorination device 3. The other steps are the same as in Specific Implementation Methods 1 to 4.

[0060] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that it also includes an early warning system 9, which is connected to the outlet pipe of the activated carbon column 6. The other steps are the same as in Specific Implementation Methods One to Five.

[0061] The beneficial effects of the present invention are verified using the following embodiments:

[0062] Example 1: A microplastic ultrafiltration removal system, comprising a filtration system and a backwash control system;

[0063] The filtration system includes a raw water tank 1, a microplastic analysis device 2, a chlorination device 3, an ultrafiltration membrane system 4, an inlet valve group 5, an activated carbon column 6, a product water tank 7, a product water valve 13, and a PLC control system 17.

[0064] The ultrafiltration membrane system 4 consists of multiple parallel ultrafiltration membrane modules. Each membrane module is equipped with an independent water inlet pipe and a water inlet valve. Multiple water inlet valves form a water inlet valve group 5, which controls the operating status of each membrane module.

[0065] The microplastic analysis device 2 is connected to the raw water tank 1. The outlet pipe of the raw water tank 1 is connected to the outlet pipe of the chlorination device 3 and multiple inlet pipes of the ultrafiltration membrane system 4. Multiple product water outlets of the ultrafiltration membrane system 4 are connected to the inlet pipe of the activated carbon column 6 through water pipes. The outlet pipe of the activated carbon column 6 is connected to the product water tank 7.

[0066] The backwash control system includes a backwash pump 14, a backwash inlet valve 15, a backwash outlet valve 16, and a wastewater tank 8; the outlet pipe of the product water tank 7 is connected to the product water port of the ultrafiltration membrane system 4 through the backwash pump 14 and the backwash valve 15, and the concentrate port of the ultrafiltration membrane system 4 is connected to the wastewater tank 8 through a water pipe and the backwash outlet valve 16.

[0067] The PLC control system 17 is connected to and controls the microplastic analysis device 2, the chlorination device 3, the inlet valve group 5, the backwash pump 14, and the backwash inlet valve 15, respectively.

[0068] The ultrafiltration membrane system 4 consists of four parallel ultrafiltration membrane modules. Each membrane module is equipped with an independent water inlet pipe and a water inlet valve. The four water inlet valves form a water inlet valve group 5, which controls the operating status of each membrane module.

[0069] The raw water tank 1 is equipped with a raw water pump 10 on its outlet pipe;

[0070] The water outlet pipe of the raw water tank 1 is equipped with an inlet valve 11;

[0071] The chlorination device 3 is equipped with a chlorination valve 12 on its outlet pipe;

[0072] A microplastic ultrafiltration removal system also includes an early warning system 9, which is connected to the outlet pipe of the activated carbon column 6.

[0073] The workflow of the microplastic ultrafiltration removal system described in Example 1 is as follows: First, raw water is drawn from the raw water tank 1 into the microplastic analysis device 2 for real-time monitoring. The microplastic analysis device 2 uses an infrared spectral sensor and a laser particle size sensor to detect the type, particle size distribution (distinguishing between <1μm, 1-10μm, and >10μm) and concentration of microplastics in real time. After the detection data is uploaded to the PLC control system 17, the chlorine dosage of the chlorination device 3 is dynamically adjusted through the built-in algorithm. When the proportion of <10μm microplastics exceeds 60%, the chlorine dosage is limited to ≤0.5mg / L to prevent excessive oxidation and breakage. For PET (polyethylene terephthalate resin) or PVC (polyvinyl chloride resin) and other recalcitrant plastics, the dosage is increased to 1.0-1.5mg / L to enhance the pretreatment effect.

[0074] The ultrafiltration membrane system 4 uses four sets of parallel PVDF hollow fiber membrane modules (each set with an area of ​​50m²). The PLC control system 17 calculates the number of membrane modules to be activated based on the real-time treatment volume and microplastic concentration. For example, when the treatment volume is 80m³ / h and the concentration is 3000 particles / L, all four sets of membranes are automatically activated. At the same time, one set of membranes is rotated into standby mode every 2 hours to balance the fouling load. If the transmembrane pressure difference (TMP) of a single set of membranes is 15% higher than that of other sets, its inlet valve opening is automatically reduced to 70%.

[0075] In the post-treatment stage, water flows through activated carbon column 6 to adsorb residual nano-sized microplastics and remove residual chlorine. The early warning system 9, using a laser particle size analyzer, immediately activates the PLC control system 17 when the number of particles >0.1μm exceeds 10 / mL or the residual chlorine is ≥0.15mg / L. This triggers an additional membrane unit to be started, the backwashing frequency of activated carbon column 6 is increased to 2 times / h, and the permeate valve 13 is closed, switching to wastewater tank 8. Simultaneously, an alarm message is sent to the monitoring center via the Modbus TCP protocol. During installation and commissioning, it is essential to ensure that the four membrane units are arranged in a regular quadrilateral with a center-to-center distance ≥1.5m. The microplastic analyzer is calibrated daily using standard polystyrene microspheres to within ±5% of the error, and the backwashing fuzzy control weight coefficients are optimized through the self-learning function of the PLC control system 17.

[0076] The microplastic analysis device 2 used in Example 1 is an integrated and innovative device, whose core components are all integrated using commercially available standard sensor modules, including:

[0077] ① Infrared spectral sensor (e.g., ThermoFisher Nicolet iS5, used for microplastic identification, detection wavelength range 7800-350cm); connected to the PLC analog input module via a 4-20mA analog signal; used for microplastic identification;

[0078] ② Laser particle size sensor (e.g., Malvern Mastersizer 3000, used for particle size distribution detection, range 0.01-3500μm); uses Modbus RTU protocol to communicate with PLC via RS485 bus; used for particle size distribution detection;

[0079] ③ Mass flow sensor (model such as Siemens SITRANSFC430, used for quantitative analysis of content, measurement accuracy ±0.5%); three-wire connection (brown wire to 24VDC positive terminal, blue wire to common terminal, black signal wire to PLC digital input channel); used for quantitative analysis of content;

[0080] ④ Image acquisition module (using a Baslerace series industrial camera with a resolution ≥ 5 megapixels, and morphological analysis using the OpenCV open-source library); fixed via a C-Mount industrial lens mount; performing morphological analysis. The infrared spectral sensor, laser particle size sensor, mass flow sensor, and image acquisition module are all existing devices and technologies.

[0081] The PLC control system 17 used in this invention is an industrial-grade PLC controller, selected from either Siemens S7-1200 series (model: 6ES7214-1HG40-0XB0) or Mitsubishi Electric FX5U-32MT / ES series. The PLC control system 17 has been widely used in the water treatment field and features: multi-channel analog input (supporting 4-20mA sensor signal access), industrial Ethernet communication protocol (Modbus TCP / IP), and fuzzy control algorithm module (for dynamically adjusting ultrafiltration parameters).

[0082] The PLC control system 17 used in Example 1 is an industrial-grade PLC controller, selected from either Siemens S7-1200 series (model: 6ES7214-1HG40-0XB0) or Mitsubishi Electric FX5U-32MT / ES series. The PLC control system 17 has been widely used in the water treatment field and features: multi-channel analog input (supporting 4-20mA sensor signal access), industrial Ethernet communication protocol (ModbusTCP), and fuzzy control algorithm module (for dynamically adjusting ultrafiltration parameters).

Claims

1. A microplastic ultrafiltration removal system characterized in that A microplastic ultrafiltration removal system includes a filtration system and a backwash control system; The filtration system includes a raw water tank (1), a microplastic analysis device (2), a chlorination device (3), an ultrafiltration membrane system (4), an inlet valve group (5), an activated carbon column (6), a product water tank (7), a product water valve (13), and a PLC control system (17). The ultrafiltration membrane system (4) consists of multiple parallel ultrafiltration membrane groups. Each membrane group is equipped with an independent water inlet pipe and a water inlet valve. Multiple water inlet valves form a water inlet valve group (5), which controls the operating status of each membrane group. The microplastic analysis device (2) is connected to the raw water tank (1). The outlet pipe of the raw water tank (1) is connected to the outlet pipe of the chlorination device (3) and multiple inlet pipes of the ultrafiltration membrane system (4). Multiple product outlets of the ultrafiltration membrane system (4) are connected to the inlet pipe of the activated carbon column (6) through water pipes. The outlet pipe of the activated carbon column (6) is connected to the product water tank (7). The backwash control system includes a backwash pump (14), a backwash inlet valve (15), a backwash outlet valve (16), and a wastewater tank (8); the outlet pipe of the product water tank (7) is connected to the product water port of the ultrafiltration membrane system (4) through the backwash pump (14) and the backwash valve (15), and the concentrate port of the ultrafiltration membrane system (4) is connected to the wastewater tank (8) through the water pipe and the backwash outlet valve (16); The PLC control system (17) is connected to the microplastic analysis device (2), chlorination device (3), water inlet valve group (5), backwash pump (14) and backwash water inlet valve (15) respectively, and controls them.

2. The microplastics ultrafiltration removal system of claim 1, wherein The ultrafiltration membrane system (4) consists of four parallel ultrafiltration membrane groups. Each membrane group is equipped with an independent water inlet pipe and a water inlet valve. The four water inlet valves form a water inlet valve group (5), which controls the operating status of each membrane group.

3. The microplastics ultrafiltration removal system of claim 1, wherein The raw water tank (1) is equipped with a raw water pump (10) on its outlet pipe.

4. The microplastics ultrafiltration removal system of claim 1, wherein The water outlet pipe of the raw water tank (1) is equipped with an inlet valve (11).

5. The microplastics ultrafiltration removal system of claim 1, wherein The chlorination device (3) is equipped with a chlorination valve (12) on its outlet pipe.

6. The microplastics ultrafiltration removal system of claim 1, wherein It also includes an early warning system (9), which is connected to the outlet pipe of the activated carbon column (6).

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