Agricultural field irrigation water treatment system without chemicals

Abstract

This utility model discloses a chemical-free farmland irrigation water treatment system, belonging to the field of farmland irrigation water treatment. The system includes, in sequence, a raw water tank, a sedimentation tank, a storage tank, a filtration system, a filtered product water tank, a bipolar membrane electrodialysis device, a water tank, an electrodialysis system, and a water reservoir. The desalinated liquid outlet of the bipolar membrane electrodialysis device is connected to the sedimentation tank via a first pipe, and the concentrated liquid outlet of the electrodialysis system is connected to the first pipe via a second pipe. This utility model eliminates the need for any added chemicals throughout the process, reducing treatment costs, preventing soil and groundwater pollution caused by chemical residues, achieving an environmentally friendly closed loop through concentrated liquid recycling, and precisely desalinating to produce compliant irrigation water, thus balancing cost, environmental protection, and water resource utilization efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of farmland irrigation water treatment, and in particular relates to a pesticide-free farmland irrigation water treatment system. Background Technology

[0002] Brackish water areas are widely distributed across my country's vast territory, especially in arid and semi-arid regions such as the Northwest and North China, where the proportion of brackish water coverage is not small. These regions are already short of water resources, and brackish water contains excessive amounts of salt, minerals, and various dissolved impurities, causing its water quality to far exceed the tolerance range for crop growth.

[0003] For a long time, traditional methods for treating brackish water irrigation have relied on adding chemical agents to soften the water and remove harmful components. However, this approach has many drawbacks. On the one hand, the cost of these agents is high, and long-term investment is a heavy burden for large-scale agricultural irrigation. On the other hand, agent residues may pollute the soil and groundwater environment, causing secondary ecological damage, and there are certain safety risks during the transportation and storage of these agents. Meanwhile, with increasingly stringent environmental protection requirements and the promotion of green agricultural development, finding efficient, economical, and environmentally friendly brackish water treatment methods is urgently needed.

[0004] Against this backdrop, there is an urgent need to develop a chemical-free irrigation water treatment system for farmland in brackish water areas. Utility Model Content

[0005] The purpose of this invention is to propose a pesticide-free farmland irrigation water treatment system to overcome at least one of the above-mentioned defects in the prior art.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This utility model provides a pesticide-free farmland irrigation water treatment system, which includes a raw water tank, a sedimentation tank, a water storage tank, a filtration system, a filtered water production tank, a bipolar membrane electrodialysis device, a water tank, an electrodialysis system, and a water tank arranged in sequence. The desalination liquid outlet of the bipolar membrane electrodialysis device is connected to the sedimentation tank through a first pipe, and the concentrate outlet of the electrodialysis system is connected to the first pipe through a second pipe.

[0008] Preferably, the bipolar membrane electrodialysis device includes a first concentration chamber and a first desalination chamber. The outlet of the filtered water product tank is connected to the first concentration chamber and the first desalination chamber respectively. The desalinated liquid outlet of the first desalination chamber is connected to the sedimentation tank through a first pipe. The concentrated liquid outlet of the first concentration chamber is connected to the water tank.

[0009] Preferably, the electrodialysis system includes a second concentration chamber and a second desalination chamber, with the water tank outlet connected to both the second concentration chamber and the second desalination chamber, the concentrate outlet of the second concentration chamber connected to the first pipe via a second pipe, and the desalination outlet of the second desalination chamber connected to the water tank.

[0010] Preferably, the filtration system includes one or more of an ultrafiltration system, a microfiltration system, or a nanofiltration system.

[0011] Preferably, it also includes a first pH meter, a second pH meter, a third pH meter, and a fourth pH meter. The probe end of the first pH meter extends to the upper part of the sedimentation tank, the probe end of the second pH meter extends into the water tank, the probe end of the third pH meter extends into the first pipe and is located near the desalination liquid outlet of the bipolar membrane electrodialysis device, and the probe end of the fourth pH meter extends into the water tank.

[0012] Preferably, it also includes a first conductivity meter, a second conductivity meter, and a third conductivity meter. The probe end of the first conductivity meter extends into the filtered water tank, the probe end of the second conductivity meter extends into the second pipe and is located near the concentrate outlet of the electrodialysis system, and the probe end of the third conductivity meter extends into the water tank.

[0013] Preferably, the current density of the bipolar membrane electrodialysis device is 50-600 A / m 2 .

[0014] Preferably, the current density of the electrodialysis system is 20-500 A / m 2 .

[0015] The beneficial effects of this utility model are as follows:

[0016] 1. No chemicals are added throughout the process, which reduces treatment costs, eliminates soil and groundwater pollution caused by chemical residues, achieves an environmentally friendly closed loop through the recycling of concentrated liquid, and can accurately desalinate to produce irrigation water that meets standards, thus balancing cost, environmental protection and water resource utilization.

[0017] 2. The operation without chemicals saves costs and avoids pollution. It achieves green treatment by reusing the concentrate. It produces qualified irrigation water through dual desalination processes, effectively treats brackish water and improves its utilization rate, and protects the farmland ecology. Attached Figure Description

[0018] Figure 1 This is a system block diagram of Embodiment 1 of the present invention.

[0019] The labels in the attached diagram are as follows: 1-raw water tank, 2-sedimentation tank, 3-storage tank, 4-filtration system, 5-filtered product water tank, 6-bipolar membrane electrodialysis device, 7-water tank, 8-electrodialysis system, 9-water tank, 10-first pipeline, 11-second pipeline, 12-first pH meter, 13-second pH meter, 14-third pH meter, 15-fourth pH meter, 16-first conductivity meter, 17-second conductivity meter, 18-third conductivity meter. Detailed Implementation

[0020] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0021] Contents not described in detail in this specification are existing technologies known to those skilled in the art. In the description of this utility model, it should be understood that terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this utility model. Furthermore, terms such as "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] Example 1:

[0023] like Figure 1 As shown, this embodiment provides a pesticide-free farmland irrigation water treatment system, comprising, in sequence, a raw water tank 1, a sedimentation tank 2, a water storage tank 3, a filtration system 4, a filtered product water tank 5, a bipolar membrane electrodialysis device 6, a water tank 7, an electrodialysis system 8, and a water tank 9. The desalinated liquid outlet of the bipolar membrane electrodialysis device 6 is connected to the sedimentation tank 2 via a first pipe 10, and the concentrated liquid outlet of the electrodialysis system 8 is connected to the first pipe 10 via a second pipe 11. The bipolar membrane electrodialysis device 6 includes a first concentration chamber and a first desalination chamber. The outlet of the filtered product water tank 5 is connected to both the first concentration chamber and the first desalination chamber. The desalinated liquid outlet of the first desalination chamber is connected to the sedimentation tank 2 via the first pipe 10, and the concentrated liquid outlet of the first concentration chamber is connected to the water tank 7. The electrodialysis system 8 includes a second concentration chamber and a second desalination chamber. The outlet of the water tank 7 is connected to the second concentration chamber and the second desalination chamber respectively. The concentrated liquid outlet of the second concentration chamber is connected to the first pipe 10 through the second pipe 11. The desalination liquid outlet of the second desalination chamber is connected to the water tank 9.

[0024] This system aims at chemical-free purification. Through a stepped treatment process—pretreatment, bipolar membrane electrodialysis, and deep electrodialysis desalination—combined with a concentrate recycling design, it transforms brackish water into qualified irrigation water. The specific principle is explained in three steps:

[0025] 1. Pretreatment stage: sedimentation + filtration, reducing the workload of membrane treatment.

[0026] Raw water sedimentation (raw water tank 1 - sedimentation tank 2 - storage tank 3): The brackish water (initial mineralization 5820ppm, chloride 850ppm, sulfate 430ppm) in raw water tank 1 is pumped into sedimentation tank 2, where suspended sediment, colloids, and other particulate matter naturally settle due to gravity. After settling, the clarified liquid overflows into storage tank 3, preventing bottom sediment from clogging subsequent membrane modules and initially reducing water turbidity.

[0027] Filtration and impurity removal (storage tank 3 - filtration system 4 - filtered water tank 5): Clarified water in storage tank 3 enters filtration system 4 to remove residual fine suspended solids and organic matter, further reducing the water pollution load. The treated filtered water enters filtered water tank 5 as the feed water source for bipolar membrane electrodialysis unit 6, ensuring stable operation of the membrane module.

[0028] 2. Bipolar membrane electrodialysis stage: Acid adjustment without reagents + circulation of alkaline concentrate.

[0029] The bipolar membrane electrodialysis device 6 is the reagent-free core of the system, with a built-in first concentration chamber and a first desalination chamber. It relies on the water dissociation characteristics of the bipolar membrane and the selective permeability of the ion exchange membrane to achieve directional ion migration.

[0030] The water from filter product tank 5 is divided into two streams, pumped into the first concentration chamber and the first desalination chamber respectively. Driven by an electric field, the bipolar membrane dissociates into H₂. + And OH-. Cations in the water move towards the cathode, and anions move towards the anode, while H+... + The water is transferred to the first concentration chamber, where it eventually forms an acidic concentrate (acidic water is generated without the use of chemicals), which is then temporarily stored in water tank 7. The cations transferred to the first desalination chamber combine with the OH- ions released from the bipolar membrane to form an alkaline desalination solution. This alkaline desalination solution is then returned to sedimentation tank 2 via the first pipe 10, where its alkalinity is used to adjust the pH of the raw water and promote the settling of impurities in sedimentation tank 2 (replacing traditional chemical alkalis and achieving chemical-free pH adjustment).

[0031] 3. Electrodialysis deep desalination stage: reducing mineralization to achieve standard irrigation water quality.

[0032] The electrodialysis system 8 has a built-in second concentration chamber and a second desalination chamber, which are used to perform deep desalination of the acidic water in the water tank 7 to remove residual chlorides and sulfates.

[0033] The acidic concentrate in tank 7 is divided into two streams, pumped into the second concentration chamber and the second desalination chamber respectively. Under the influence of an electric field, the residual Cl- and SO42- in the second desalination chamber are... 2 Anions move towards the anode (entering the second concentration chamber), while a small number of cations move towards the cathode. Ultimately, the ion concentration in the second desalination chamber is significantly reduced, forming a low-mineralization desalinated solution (mineralization 1120 ppm, chloride 220 ppm, sulfate 50 ppm after treatment). This solution is directly stored in water tank 9 for use as irrigation water in farmland. The high-concentration ions accumulated in the second concentration chamber form a concentrated solution, which merges with the first pipe 10 through the second pipe 11 and flows back to the sedimentation tank 2. There, it participates in the pH adjustment of the raw water and the settling of impurities, achieving zero-discharge recycling of the concentrated solution.

[0034] This invention eliminates the need for any chemical additives throughout the entire process, directly saving the costs of purchasing, storing, and applying chemicals, thus reducing the treatment cost of farmland irrigation water. It completely avoids the problem of chemical residues, which in traditional chemical treatment methods can enter the soil with irrigation water, leading to soil compaction, heavy metal accumulation, and even groundwater pollution. Because no chemicals are added, secondary ecological harm is prevented at the source, protecting the farmland soil and groundwater environment. The alkaline concentrate produced by the bipolar membrane electrodialysis device 6 and the high-salt concentrate produced by the electrodialysis system 8 are both returned to the sedimentation tank 2 via pipelines. This system utilizes alkaline concentrate to adjust the pH of raw water to enhance sedimentation, while avoiding water pollution caused by direct discharge of the concentrate, thus achieving a closed loop of treatment, recycling, and reuse, meeting green and environmental protection requirements. The system employs a combination of bipolar membrane electrodialysis for preliminary desalination and electrodialysis for deep desalination, precisely removing mineralization, chlorides, and sulfates from brackish water. This ensures that all indicators meet the standards for farmland irrigation water, producing low-mineralized neutral water. This avoids soil salinization caused by high-salt irrigation, protects crop root health, and improves crop yield and quality. It achieves comprehensive management of brackish water and improves water resource utilization in brackish water areas.

[0035] The system includes a first pH meter 12, a second pH meter 13, a third pH meter 14, and a fourth pH meter 15. The probe of the first pH meter 12 extends to the upper part of the sedimentation tank 2 to monitor the pH of the supernatant in the sedimentation tank 2. The probe of the second pH meter 13 extends into the water tank 7 to monitor the pH of the acidic water in the water tank 7. The probe of the third pH meter 14 extends into the first pipe 10 and is located near the concentrate outlet of the bipolar membrane electrodialysis device 6 to monitor the pH of the alkaline water in the first pipe 10 in real time. The probe of the fourth pH meter 15 extends into the water tank 9 to monitor the pH of the final product water in the water tank 9. By monitoring the pH of the supernatant in the sedimentation tank 2, the acidic water in the water tank 7, the alkaline water in the first pipe 10, and the final product water in the water tank 9 with four sets of pH meters, the system can monitor the acidity and alkalinity of the water in each key link in real time, providing intuitive data for judging the system operation status.

[0036] The system includes a first conductivity meter 16, a second conductivity meter 17, and a third conductivity meter 18. The probe of the first conductivity meter 16 extends into the filtered water product tank 5 to monitor the conductivity of the filtered water product in the tank 5. The probe of the second conductivity meter 17 extends into the second pipe 11 and is positioned near the concentrate outlet of the electrodialysis system 8 to monitor the conductivity of the concentrate in the second pipe 11 in real time. The probe of the third conductivity meter 18 extends into the water tank 9 to monitor the conductivity of the final product water in the water tank 9. The three sets of conductivity meters monitor the conductivity of the product water from the filtered water product tank 5, the concentrate from the second pipe 11, and the final product water from the water tank 9, respectively, to obtain real-time data on the filtration and impurity removal effect, the ion enrichment degree of the concentrate, and the mineralization of the final product water, providing data support for understanding the ion content of the water at each stage.

[0037] Among them, the current density of the bipolar membrane electrodialysis device 6 is 50-600 A / m 2 The current density of the electrodialysis system 8 is 20-500 A / m³. 2 It can adapt to different raw water salinity levels, balancing treatment efficiency and energy consumption, and ensuring stable system operation.

[0038] Example 2:

[0039] The difference between this embodiment and Embodiment 1 lies in the raw water being treated. Before treatment, the raw water in this embodiment had a mineralization of 8300 ppm, chloride of 1000 ppm, and sulfate of 730 ppm. After treatment, the final treated water had a mineralization of 1340 ppm, chloride of 320 ppm, and sulfate of 120 ppm, thus meeting irrigation water requirements.

[0040] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A pesticide-free farmland irrigation water treatment system, characterized in that: It includes, in sequence, a raw water tank, a sedimentation tank, a water storage tank, a filtration system, a filtered product water tank, a bipolar membrane electrodialysis device, a water tank, an electrodialysis system, and a water tank; The desalination liquid outlet of the bipolar membrane electrodialysis device is connected to the sedimentation tank through a first pipe. The concentrate outlet of the electrodialysis system is connected to the first pipe via a second pipe.

2. The pesticide-free farmland irrigation water treatment system according to claim 1, characterized in that: The bipolar membrane electrodialysis device includes a first concentration chamber and a first desalination chamber; The outlet of the filtered water production tank is connected to the first concentration chamber and the first desalination chamber, respectively. The desalination liquid outlet of the first desalination chamber is connected to the sedimentation tank through a first pipe; The concentrated liquid outlet of the first concentration chamber is connected to the water tank.

3. The pesticide-free farmland irrigation water treatment system according to claim 1, characterized in that: The electrodialysis system includes a second concentration chamber and a second desalination chamber; The water tank outlet is connected to the second concentration chamber and the second desalination chamber, respectively. The concentrated liquid outlet of the second concentration chamber is connected to the first pipe through a second pipe; The desalination liquid outlet of the second desalination chamber is connected to the water tank.

4. The pesticide-free farmland irrigation water treatment system according to claim 1, characterized in that: The filtration system includes one or more of ultrafiltration, microfiltration, or nanofiltration systems.

5. The pesticide-free farmland irrigation water treatment system according to claim 1, characterized in that: It also includes a first pH meter, a second pH meter, a third pH meter, and a fourth pH meter; The probe end of the first pH meter extends above the interior of the sedimentation tank; The probe end of the second pH meter extends into the water tank; The probe end of the third pH meter extends into the first pipe and is located near the desalination liquid outlet of the bipolar membrane electrodialysis device. The probe end of the fourth pH meter extends into the water tank.

6. The pesticide-free farmland irrigation water treatment system according to claim 1, characterized in that: It also includes a first conductivity meter, a second conductivity meter, and a third conductivity meter; The probe end of the first conductivity meter extends into the filtered water production tank; The probe end of the second conductivity meter extends into the second pipe and is positioned near the concentrate outlet of the electrodialysis system. The probe end of the third conductivity meter extends into the water tank.

7. The pesticide-free farmland irrigation water treatment system according to claim 1, characterized in that: The bipolar membrane electrodialysis device has a current density of 50-600 A / m 2 .

8. The pesticide-free farmland irrigation water treatment system according to claim 1, characterized in that: The current density of the electrodialysis system is 20-500 A / m 2 .

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