Earth surface salt water desalination pretreatment method

Abstract

The invention relates to an earth surface salt water desalination pretreatment method applied to the technical field of water resource treatment. The earth surface salt water desalination pretreatment method comprises the steps of interception and water quality regulation, nano-bubble centrifugal purification, dynamic flocculent precipitation and the like. According to the treatment method disclosed by the invention, sand filtration and carbon filtration in a traditional process are replaced by an innovative nano-bubble centrifugal separation technology, so that the anti-pollution and anti-blocking capability and the treatment capacity are greatly improved, and the separation precision is also remarkably improved; a decision is made based on real-time monitoring data of turbidity and UV254 double parameters, so that the sedimentation tank is intelligently switched among a strong turbulent flow mode, a high turbulent flow mode, a medium turbulent flow mode and a low turbulent flow mode, the treatment efficiency and energy consumption are considered, efficient treatment of different water qualities is achieved, the anti-pollution and anti-blocking capacity is further improved, and the water quality can be effectively treated when facing a water body with large turbidity and many pollutants. The high treatment efficiency can be kept, the adaptability to water quality fluctuation is also remarkably improved, and the problem that the precipitation efficiency is suddenly reduced due to water quality fluctuation in the traditional process is solved.

Description

TECHNICAL FIELD

[0001] The application relates to a treatment method, in particular to a surface brackish water desalination pre-treatment method. BACKGROUND

[0002] With the increasing shortage of fresh water resources, seawater desalination and brackish water desalination technology has become an important way to alleviate the water resource crisis. The core equipment of the traditional desalination system has very strict requirements on the water quality of the inlet water. Usually, the key indicators such as pollution density index, turbidity and organic matter content of the raw water need to meet specific standards to avoid membrane pollution, flux attenuation and frequent cleaning.

[0003] At present, the raw water source of the desalination system mainly concentrates on deep well groundwater with relatively stable water quality. However, the exploitation of groundwater is limited by region and has the risk of resource exhaustion. In contrast, surface brackish water has the potential to become a desalination raw water in theory because of its wide distribution and strong accessibility. However, the surface brackish water is exposed to the open environment all the year round, has the defects of high turbidity, complex impurities and large water quality fluctuation, and needs to be strictly treated before entering the desalination system.

[0004] The Chinese invention application with the publication number CN107117772A discloses a surface runoff treatment system and method. The invention application performs primary filtration on the surface runoff through a primary filtration device and performs secondary filtration on the surface runoff through a secondary soil filtration.

[0005] The Chinese invention application with the publication number CN118878119A discloses a city surface runoff treatment system. The invention application realizes effective removal of various pollutants in rainwater runoff through multi-stage adsorption treatment.

[0006] For the pre-treatment of surface brackish water, the industry generally adopts a four-stage pretreatment process of "sand filtration→ activated carbon filtration→ precision filtration→ ultrafiltration". Although this treatment process has high precision and can realize that the water source meets the desalination inlet water requirements, the treatment capacity is small. Once the water body with large turbidity and many pollutants is encountered, the water flux will rapidly decrease and it is difficult to meet the continuous use. Therefore, the application provides a surface brackish water desalination pre-treatment method. SUMMARY

[0007] In view of the above prior art, the technical problem to be solved by the application is that the existing process has high precision and can realize that the water source meets the desalination inlet water requirements, but the treatment capacity is small. Once the water body with large turbidity and many pollutants is encountered, the water flux will rapidly decrease and it is difficult to meet the continuous use.

[0008] To solve the above problems, the application provides a surface brackish water desalination pre-treatment method, which comprises the following steps:

[0009] S1, intercepting and water quality adjustment:

[0010] S11, setting an automatic grid at the water intake to intercept and remove impurities from raw water;

[0011] S12, pumping the water into a pipeline mixer, and adjusting the pH of the raw water through the pH online adjustment unit in the pipeline mixer;

[0012] S2, nano-bubble centrifugal purification: sending the water treated in step S1 into a centrifugal cyclone separator, and simultaneously injecting an oxidizing agent into the separator to separate micron-sized impurities;

[0013] S3, dynamic flocculation and sedimentation: sending the water treated in step S2 into a dynamic adjustment sedimentation tank, switching the operation mode of the dynamic adjustment sedimentation tank based on real-time water quality parameters, and adding 10-50 ppm polyaluminum chloride flocculant at a position 0.4-0.6 m upstream of the water inlet of the dynamic adjustment sedimentation tank;

[0014] S4, three-stage filtration: making the water treated in step S3 pass through a coarse filter with a pore size of 100 μm, an electric adsorption filter, and a precision filter with a pore size of 5 μm in sequence;

[0015] The dynamic adjustment sedimentation tank is provided with a rotatable guide plate group and a variable-frequency turbulence generator array. The rotatable guide plate group includes a plurality of guide plates and a servo motor for adjusting the rotation angle of the guide plates. The variable-frequency turbulence generator array is composed of a plurality of turbulence generators configured with variable-frequency function.

[0016] The switching of the operation mode of the dynamic adjustment sedimentation tank is based on a dynamic adjustment system. The dynamic adjustment system includes a water quality monitoring module and a mode adjustment module. The water quality monitoring module is used to obtain real-time water quality parameters through a turbidity sensor and an absorbance sensor. The mode adjustment module is used to switch the operation mode of the dynamic adjustment sedimentation tank by adjusting the inclination angle of the guide plates and the frequency of the turbulence generators according to the real-time water quality parameters.

[0017] In the above-mentioned surface brackish water desalination pretreatment method, the innovative nano-bubble centrifugal separation technology replaces the sand filter and carbon filter in the traditional process, which not only improves the anti-pollution blocking capacity and treatment capacity, but also significantly improves the separation precision.

[0018] As a further improvement of the present application, the turbidity sensor and the absorbance sensor are both arranged at the water outlet of the separator. The water quality monitoring module is signal-connected with the mode adjustment module. The mode adjustment module is signal-connected with the servo motor and the turbulence generator.

[0019] As a further improvement of the present application, the real-time water quality parameters include the turbidity T1 obtained through the turbidity sensor and the absorbance A obtained through the absorbance sensor. The absorbance is the absorbance of water under 254 nm wavelength ultraviolet light.

[0020] When A > 0.22 cm -1 and T1 > 150 NTU, the mode adjustment module controls the servo motor to adjust the inclination angle of the guide plate to 70°, and controls the spoiler to run at a frequency of 60 Hz, so that the dynamic adjustment sedimentation tank runs in a strong turbulent mode;

[0021] When A > 0.22 cm -1 and T1≤150 NTU, the mode adjustment module controls the servo motor to adjust the inclination angle of the guide plate to 55-65°, and controls the spoiler to run at a frequency of 45-55 Hz, so that the dynamic adjustment sedimentation tank runs in a high turbulent mode;

[0022] When A≤0.22 cm -1 and T1 > 150 NTU, the mode adjustment module controls the servo motor to adjust the inclination angle of the guide plate to 40-50°, and controls the spoiler to run at a frequency of 30-40 Hz, so that the dynamic adjustment sedimentation tank runs in a medium turbulent mode;

[0023] When A≤0.22 cm -1 and T1≤150 NTU, the mode adjustment module controls the servo motor to adjust the inclination angle of the guide plate to 10-15°, and controls the spoiler to run at a frequency of 8-12 Hz, so that the dynamic adjustment sedimentation tank runs in a low turbulent mode.

[0024] As a further improvement of the present application, the rotatable guide plate group is located at a distance of 0.3-0.5L from the inlet of the dynamic adjustment sedimentation tank, L is the length of the dynamic adjustment sedimentation tank, and the height of the lower end of the guide plate from the bottom of the dynamic adjustment sedimentation tank is 0.4H-0.6H, H is the design water depth, the total width of the guide plate group accounts for 80%-95% of the width of the dynamic adjustment sedimentation tank, and the spacing between adjacent guide plates is 0.8-1.2 times the width of the guide plate.

[0025] As a further improvement of the present application, the pH online adjustment unit is configured to control the pH of the raw water to 6.5-7.5 by adding food-grade acid or alkali agent, and the oxidizing agent in step S2 is ozone, which is injected in the form of nano bubbles with a concentration of 5-8 mg / L.

[0026] As another improvement of the present application, step S1 further comprises:

[0027] S11.5, pumping the intercepted and impurity-removed raw water into a stainless steel adjustment tank, homogenizing the raw water by a submersible agitator arranged in the tank, and achieving water quality homogenization by hydraulic retention for 15-30 minutes;

[0028] Step S11.5 is after step S11 and before step S12.

[0029] As a supplement to another improvement of the present application, the injection of oxidant in step S2 is dynamically adjusted according to the algae identification result:

[0030] The oxidant is ozone with a concentration of 5-8 mg / L by default, which is injected in the form of nano-bubbles;

[0031] When the proportion of green algae cells is >60%, the oxidant is adjusted to ozone with a concentration of 10-16 mg / L, which is injected in the form of jet flow;

[0032] The algae identification result is obtained based on a microscopic imaging analyzer installed at the outlet of the conditioning tank.

[0033] As a supplement to another improvement of the present application, the dynamic adjustment system further comprises a rotating speed adjustment module, and the water quality monitoring module is further configured to obtain turbidity T2 through a turbidity sensor two arranged at the outlet of the conditioning tank, and the water quality monitoring module is signal-connected with the rotating speed adjustment module.

[0034] As a supplement to another improvement of the present application, the rotating speed of the separator in step S2 is dynamically adjusted according to T2;

[0035] When T2≤100 NTU, the rotating speed adjustment module controls the separator to operate at a rotating speed of 800 rpm;

[0036] When 100 NTU

[0037] When T2>300 NTU, the rotating speed adjustment module controls the separator to increase the rotating speed to 1200 rpm.

[0038] As a supplement to another improvement of the present application, when the rising value of T2 within 1 minute is >50 NTU, the rotating speed adjustment module controls the separator to directly increase the rotating speed to 1200 rpm.

[0039] In summary, the treatment method in the present application replaces the sand filter and carbon filter in the traditional process by the innovative nano-bubble centrifugal separation technology, which not only greatly improves the anti-fouling capacity and treatment capacity, but also significantly improves the separation precision; the real-time monitoring data of turbidity and UV254 are used for decision-making, so that the sedimentation tank intelligently switches between four turbulence modes of strong, high, medium and low, taking into account the treatment efficiency and energy consumption, realizing efficient treatment of different water qualities, further improving the anti-fouling capacity, maintaining high treatment efficiency when facing water bodies with high turbidity and many pollutants, and significantly improving the adaptability to water quality fluctuations, solving the problem of sudden reduction of sedimentation efficiency caused by water quality fluctuations in the traditional process;

[0040] This application also includes a dynamic adjustment mechanism for oxidants, which can achieve precise inactivation based on the differences in algal cell wall structure. This not only improves the efficiency of targeted inactivation of algae, but also reduces drug consumption costs and improves economic benefits.

[0041] This application addresses three major pain points in the treatment of high-turbidity surface saline water: "equipment vulnerability, high energy consumption, and fluctuating separation accuracy" through real-time turbidity sensing, dynamic speed matching, and mutation rate threshold response. It not only balances the efficiency and energy consumption of the separator but also protects the equipment. Attached Figure Description

[0042] Figure 1 This is a flowchart of the processing method in the first embodiment of this application;

[0043] Figure 2 This is a structural block diagram of the dynamic adjustment system in the first embodiment of this application;

[0044] Figure 3 This is a flowchart illustrating the logic of the mode adjustment module switching the operating mode of the dynamic sedimentation tank in the first embodiment of this application.

[0045] Figure 4 This is a flowchart of the processing method in the second embodiment of this application;

[0046] Figure 5 This is a flowchart illustrating the logic of dynamically adjusting the oxidant based on algae identification results in the second embodiment of this application.

[0047] Figure 6 This is a structural block diagram of the dynamic adjustment system in the second embodiment of this application;

[0048] Figure 7 This is a logic flowchart of the speed adjustment module dynamically adjusting the separator speed in the second embodiment of this application. Detailed Implementation

[0049] The two embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0050] First implementation method:

[0051] Figures 1-3 This paper presents a pretreatment method for surface saline water desalination, comprising the following steps:

[0052] S1. Interception and water quality regulation:

[0053] S11. An automatic screen is installed at the water intake to intercept and remove impurities from the raw water. The screen gap is 3mm to intercept large particles of debris such as tree branches and plastic.

[0054] S12. Pump water into the pipeline mixer and adjust the pH of the raw water through the pH online adjustment unit in the pipeline mixer. The pH online adjustment unit is configured to control the pH of the raw water at 6.5-7.5 by adding food-grade acid or alkali (such as food-grade sodium hydroxide or citric acid).

[0055] S2. Nanobubble Centrifugal Purification: The water treated in step S1 is sent to a centrifugal hydrocyclone separator, and an oxidant is injected into the separator simultaneously to achieve the separation of micron-level impurities. The oxidant is ozone, injected in the form of nanobubbles at a concentration of 5-8 mg / L. Centrifugal separation is coupled with nanobubble flotation technology. The nanobubbles break in the centrifugal field to generate local high temperature and high pressure, which pulverizes the cell walls of microalgae and releases intracellular pollutants for subsequent removal. By replacing sand filtration and carbon filtration in traditional processes with innovative nanobubble centrifugal separation technology, not only is the anti-fouling ability and processing capacity greatly improved, but the separation accuracy is also significantly improved.

[0056] S3, Dynamic Flocculation and Sedimentation: The water treated in step S2 is sent to the dynamic sedimentation tank. The operation mode of the dynamic sedimentation tank is switched based on real-time water quality parameters. 10-50ppm of polyaluminum chloride flocculant is added 0.4-0.6m upstream of the inlet of the dynamic sedimentation tank.

[0057] S4. Three-stage filtration: The water treated in step S3 is passed sequentially through a coarse filter with a pore size of 100μm, an electro-adsorption filter, and a precision filter with a pore size of 5μm.

[0058] The dynamic sedimentation tank is equipped with a rotatable guide plate assembly and a variable frequency baffle array. The rotatable guide plate assembly includes multiple guide plates and a servo motor for adjusting the rotation angle of the guide plates. The variable frequency baffle array consists of multiple baffles equipped with variable frequency functions.

[0059] The rotatable guide plate assembly is located 0.3-0.5L from the inlet of the dynamic sedimentation tank, where L is the length of the dynamic sedimentation tank, and the height of the lower end of the guide plate from the bottom of the dynamic sedimentation tank is 0.4H-0.6H, where H is the design water depth. The total width of the guide plate assembly accounts for 80%-95% of the width of the dynamic sedimentation tank, and the spacing between adjacent guide plates is 0.8-1.2 times the width of the guide plate.

[0060] The switching of the operating mode of the dynamic sedimentation tank is based on the dynamic adjustment system, which includes a water quality monitoring module and a mode adjustment module. The water quality monitoring module is used to obtain real-time water quality parameters through a turbidity sensor and an absorbance sensor. The mode adjustment module is used to switch the operating mode of the dynamic sedimentation tank according to the real-time water quality parameters by adjusting the inclination angle of the guide plate and the frequency of the turbulence generator.

[0061] Both the turbidity sensor and the absorbance sensor are located at the outlet of the separator. The water quality monitoring module is connected to the mode adjustment module by signal, and the mode adjustment module is connected to the servo motor and the turbulence breaker by signal. The real-time water quality parameters include the turbidity T1 (turbidity of the water after step S2) obtained by the turbidity sensor and the absorbance A obtained by the absorbance sensor. The absorbance is the absorbance of water under ultraviolet light at a wavelength of 254nm (UV254).

[0062] The mechanism by which the mode adjustment module switches the operating mode of the dynamic sedimentation tank is as follows:

[0063] When A > 0.22cm -1 When T1 > 150 NTU, the mode adjustment module controls the servo motor to adjust the tilt angle of the guide plate to 70° and controls the turbulent device to run at a frequency of 60 Hz, so that the dynamic sedimentation tank runs in a strong turbulent flow mode, which can completely eliminate the caking and colloidal penetration of high turbidity wastewater.

[0064] When A > 0.22cm -1 When T1≤150NTU, the mode adjustment module controls the servo motor to adjust the tilt angle of the guide plate to 55-65° and controls the turbulent device to run at a frequency of 45-55Hz, so that the dynamic sedimentation tank operates in a high turbulence mode, thus solving the problem of colloid removal in water with high organic matter content.

[0065] When A≤0.22cm -1 When T1 > 150 NTU, the mode adjustment module controls the servo motor to adjust the tilt angle of the guide plate to 40-50° and controls the turbulent device to run at a frequency of 30-40 Hz, so that the dynamic sedimentation tank operates in a medium turbulent mode, promoting sedimentation and reducing energy consumption.

[0066] When A≤0.22cm -1 When T1≤150NTU, the mode adjustment module controls the servo motor to adjust the tilt angle of the guide plate to 10-15° and controls the turbulent device to run at a frequency of 8-12Hz, so that the dynamic sedimentation tank operates in a low turbulence mode, protecting the flocs and further reducing energy consumption.

[0067] Decisions are made based on real-time monitoring data of turbidity and UV254 dual parameters, enabling the sedimentation tank to intelligently switch between four turbulence modes: strong, high, medium, and low. This balances treatment efficiency and energy consumption, achieving efficient treatment of different water qualities. Even when dealing with water bodies with high turbidity and a large number of pollutants, it can maintain high treatment efficiency and significantly improve adaptability to water quality fluctuations. This solves the problem of sedimentation efficiency dropping sharply due to water quality fluctuations in traditional processes.

[0068] The treatment method described in this application achieves efficient and intelligent pretreatment of surface saline water. Through automatic bar screening, large particulate impurities are effectively removed, providing a good foundation for subsequent treatment. The configuration of the online pH adjustment unit ensures the stability of the raw water's pH value, which is beneficial for subsequent treatment steps. The nanobubble centrifugal purification technology utilizes the special effect of nanobubbles in the centrifugal field, not only improving anti-fouling ability and treatment capacity and achieving the separation of micron-level impurities, but also pulverizing microalgae cell walls, releasing intracellular pollutants, and improving treatment efficiency. Through real-time monitoring of water quality parameters and intelligent switching of the dynamic sedimentation tank's operating mode, efficient treatment of different water qualities is achieved. The three-stage filtration process further improves the water purification level, ensuring the quality of the effluent.

[0069] Second implementation method:

[0070] Figure 4 - Similarly, 7 illustrates a pretreatment method for surface saline water desalination, which differs from the first embodiment in that step S1 further includes:

[0071] S11.5. Pump the intercepted and impurity-removed raw water into a stainless steel equalization tank. Use a submersible agitator installed in the tank to homogenize the raw water. Hydraulic retention time is 15-30 minutes to achieve water quality homogenization.

[0072] Step S11.5 is after step S11 and before step S12.

[0073] In this embodiment, the injection of oxidant in step S2 is dynamically adjusted based on the algae identification results. The logic for this dynamic adjustment is as follows:

[0074] The oxidant is ozone with a concentration of 5-8 mg / L, which is injected in the form of nanobubbles (same as the first implementation method);

[0075] When the proportion of green algae cells is >60%, the oxidant is adjusted to ozone with a concentration of 10-16 mg / L and injected in the form of a jet.

[0076] The algae identification results were obtained using a microscopic imaging analyzer installed at the outlet of the equalization tank.

[0077] Green algae cell walls contain high-density cellulose and antioxidant enzymes. Ozone at the default concentration (5-8 mg / L) is difficult to penetrate the cell wall effectively, and intracellular peroxidases rapidly decompose ozone free radicals. In this embodiment, when the proportion of green algae cells is >60%, increasing the ozone concentration to 10-16 mg / L significantly increases the rate of hydroxyl radical generation, breaking down the extracellular enzyme defense system of green algae cells. Furthermore, changing the ozone injection method to a jet stream generates turbulent vortices that significantly increase the collision frequency between ozone microbubbles and algal cells, overcoming the hydrophobic barrier of the green algae cell wall, thereby achieving highly efficient inactivation of green algae cells.

[0078] Therefore, by setting up a dynamic adjustment mechanism for oxidants, this application can achieve precise inactivation based on the differences in algal cell wall structure, which can not only improve the efficiency of targeted inactivation of algae, but also reduce drug consumption costs and improve economic benefits.

[0079] The dynamic adjustment system also includes a speed regulation module, and the water quality monitoring module is used to obtain turbidity T2 (turbidity of the homogenized water in the equalization tank) through a turbidity sensor 2 set at the outlet of the equalization tank. The water quality monitoring module is connected to the speed regulation module.

[0080] The separator speed in step S2 is dynamically adjusted according to T2;

[0081] When T2≤100NTU, the speed regulation module controls the separator to run at 800rpm, saving energy;

[0082] When 100NTU<T2≤300NTU, the speed regulation module controls the separator to increase the speed to 1000rpm, balancing efficiency and energy consumption;

[0083] When T2 > 300 NTU, the speed regulation module controls the separator to increase the speed to 1200 rpm to resist shock.

[0084] When T2 increases by more than 50 NTU within one minute, the speed regulation module controls the separator to directly increase the speed to 1200 rpm. For example, when turbidity rises sharply at the beginning of a rainstorm, the speed is immediately increased to 1200 rpm to prevent large particles from depositing and damaging the bearings.

[0085] By using real-time turbidity sensing, dynamic speed matching, and mutation rate threshold response, the system solves the three major pain points in the treatment of high-turbidity surface saline water: "equipment vulnerability, high energy consumption, and fluctuating separation accuracy". It not only balances the efficiency and energy consumption of the separator, but also protects the equipment.

[0086] In light of current practical needs, the above-described embodiments adopted in this application are not limited to these. Any changes made within the scope of knowledge possessed by those skilled in the art without departing from the concept of this application still fall within the protection scope of this invention.

Claims

1. A pretreatment method for surface saline water desalination, characterized in that, Includes the following steps: S1. Interception and water quality regulation: S11. Install an automatic screen at the water intake to intercept and remove impurities from the raw water; S12. Pump water into the pipeline mixer and adjust the pH of the raw water through the online pH adjustment unit in the pipeline mixer; S2, Nanobubble Centrifugal Purification: The water treated in step S1 is sent into a centrifugal hydrocyclone separator, and an oxidant is injected into the separator simultaneously. S3, Dynamic Flocculation and Sedimentation: The water treated in step S2 is sent to the dynamic sedimentation tank. The operation mode of the dynamic sedimentation tank is switched based on real-time water quality parameters. 10-50ppm of polyaluminum chloride flocculant is added 0.4-0.6m upstream of the inlet of the dynamic sedimentation tank. S4. Three-stage filtration: The water treated in step S3 is passed sequentially through a coarse filter with a pore size of 100μm, an electro-adsorption filter, and a precision filter with a pore size of 5μm. The dynamic sedimentation tank is equipped with a rotatable guide plate assembly and a variable frequency baffle array. The rotatable guide plate assembly includes multiple guide plates and a servo motor for adjusting the rotation angle of the guide plates. The variable frequency baffle array consists of multiple baffles configured with variable frequency function. The switching of the operating mode of the dynamic sedimentation tank is based on a dynamic adjustment system, which includes a water quality monitoring module and a mode adjustment module. The water quality monitoring module is used to acquire real-time water quality parameters through a turbidity sensor and an absorbance sensor. The mode adjustment module is used to switch the operating mode of the dynamic sedimentation tank according to the real-time water quality parameters by adjusting the inclination angle of the guide plate and the frequency of the turbulence generator.

2. The pretreatment method for surface saline water desalination according to claim 1, characterized in that, Both the turbidity sensor and the absorbance sensor are located at the outlet of the separator. The water quality monitoring module is connected to the mode adjustment module, and the mode adjustment module is connected to the servo motor and the flow disruptor.

3. The pretreatment method for surface saline water desalination according to claim 2, characterized in that, The real-time water quality parameters include turbidity T1 obtained by turbidity sensor 1 and absorbance A obtained by light absorption sensor, wherein the absorbance is the absorbance of water under ultraviolet light at a wavelength of 254nm. When A > 0.22cm -1 When T1 > 150 NTU, the mode adjustment module controls the servo motor to adjust the tilt angle of the guide plate to 70° and controls the turbulent device to run at a frequency of 60 Hz, so that the dynamic sedimentation tank runs in a strong turbulent flow mode. When A > 0.22cm -1 When T1≤150NTU, the mode adjustment module controls the servo motor to adjust the tilt angle of the guide plate to 55-65°, and controls the turbulent device to run at a frequency of 45-55Hz, so that the dynamic sedimentation tank operates in a high turbulence mode. When A≤0.22cm -1 When T1 > 150 NTU, the mode adjustment module controls the servo motor to adjust the tilt angle of the guide plate to 40-50° and controls the turbulent device to run at a frequency of 30-40 Hz, so that the dynamic sedimentation tank operates in medium turbulence mode. When A≤0.22cm -1 When T1≤150NTU, the mode adjustment module controls the servo motor to adjust the tilt angle of the guide plate to 10-15° and controls the turbulent device to run at a frequency of 8-12Hz, so that the dynamic sedimentation tank operates in a low turbulence mode.

4. The pretreatment method for surface saline water desalination according to claim 3, characterized in that, The rotatable guide plate assembly is located 0.3-0.5L from the inlet of the dynamic sedimentation tank, where L is the length of the dynamic sedimentation tank. The lower end of the guide plate is 0.4H-0.6H above the bottom of the dynamic sedimentation tank, where H is the design water depth. The total width of the guide plate assembly accounts for 80%-95% of the width of the dynamic sedimentation tank, and the spacing between adjacent guide plates is 0.8-1.2 times the width of the guide plate.

5. The pretreatment method for surface saline water desalination according to claim 1, characterized in that, The pH online adjustment unit is configured to control the pH of the raw water at 6.5-7.5 by adding food-grade acid or alkali. The oxidant in step S2 is ozone, which is injected in the form of nanobubbles at a concentration of 5-8 mg / L.

6. The pretreatment method for surface saline water desalination according to claim 1, characterized in that, Step S1 further includes: S11.

5. Pump the intercepted and impurity-removed raw water into a stainless steel equalization tank, and homogenize the raw water using a submersible agitator installed in the tank, with a hydraulic retention time of 15-30 minutes. Step S11.5 is after step S11 and before step S12.

7. A pretreatment method for surface saline water desalination according to claim 6, characterized in that, The injection of oxidant in step S2 is dynamically adjusted based on the algae identification results: The oxidant is ozone with a concentration of 5-8 mg / L, injected in the form of nanobubbles by default; When the proportion of green algae cells is >60%, the oxidant is adjusted to ozone with a concentration of 10-16 mg / L and injected in the form of a jet. The algae identification results were obtained using a microscopic imaging analyzer installed at the outlet of the regulating tank.

8. A pretreatment method for surface saline water desalination according to claim 7, characterized in that, The dynamic adjustment system also includes a speed regulation module, and the water quality monitoring module is used to obtain turbidity T2 through a turbidity sensor 2 installed at the outlet of the regulating tank. The water quality monitoring module is signal-connected to the speed regulation module.

9. A pretreatment method for surface saline water desalination according to claim 8, characterized in that, The separator speed in step S2 is dynamically adjusted according to T2. When T2≤100NTU, the speed regulation module controls the separator to run at a speed of 800rpm; When 100NTU<T2≤300NTU, the speed regulation module controls the separator to increase the speed to 1000rpm; When T2 > 300 NTU, the speed regulation module controls the separator to increase the speed to 1200 rpm.

10. A pretreatment method for surface saline water desalination according to claim 9, characterized in that, When T2 increases by more than 50 NTU within one minute, the speed regulation module controls the separator to directly increase the speed to 1200 rpm.

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