Farmland non-point source phosphorus pollution precise treatment system and control method based on enrichment-reuse

Abstract

The invention discloses a farmland non-point source phosphorus pollution precise treatment system based on enrichment-reuse and a control method thereof. The farmland non-point source phosphorus pollution precise treatment system comprises a water control unit, a purification unit, a desorption unit and an energy supply unit. The purification unit is mounted in the water control unit, and the water control unit is externally connected with the desorption unit; the water control unit is used for water flow control; the purification unit is used for purifying the farmland non-point source polluted water and comprises directional phosphorus absorption matrix filler, and the directional phosphorus absorption matrix filler is lanthanum-based coating molecular balls and lanthanum-based coating molecular bricks; the desorption unit is used for desorbing when the phosphorus adsorption capacity of the purification unit is saturated; the energy supply unit is used for supplying power to the system; accurate treatment of farmland non-point source phosphorus pollution based on enrichment-reuse is realized.

Description

Technical Field

[0001] The present invention relates to the field of farmland non-point source pollution control, and specifically to a precise control system for farmland non-point source phosphorus pollution based on enrichment and reuse and its control method. Background Technique

[0002] Farmland non-point source pollution refers to the nutrients generated by the unreasonable use of chemical fertilizers. Driven by precipitation and affected by topography, the farmland return water is formed in the forms of farmland surface runoff, farmland drainage, and underground leakage. Nutrients such as nitrogen and phosphorus, as well as organic or inorganic pollutants such as pesticides and heavy metals, pollute the adjacent receiving water bodies, with characteristics such as randomness, dispersion, and wide range. The problem of farmland non-point source pollution has become a key factor affecting the water quality of river basins such as rivers and lakes, which is not conducive to the realization of green, sustainable, and high-quality agricultural development. In addition, the production of phosphate fertilizers mainly relies on phosphate rocks with limited reserves. From a resource strategy perspective, it is necessary to further improve the utilization efficiency of phosphorus in farmland. The farmland return water during the fertilization period is fertile water. Therefore, concentrating the nutrients in the farmland return water and recycling them to the farmland to supply crop growth is a solution to simultaneously solve environmental pollution and improve fertilizer utilization efficiency.

[0003] In the prior art, the main ways to reduce and reuse nutrients are the ecological pond method, the plant absorption method, and the filler adsorption method: (1) The ecological pond is obtained by carrying out waterway and ecological transformation using surrounding ponds and wetlands. Through the control of sluice valves, the high-concentration surface runoff in the early stage enters the ecological pond, and when water is needed in the farmland in the later stage, it is preferentially dispatched. The ecological pond method has achieved good benefits of "storing in small amounts and withdrawing in large amounts" for non-point source sewage, but this method requires a sufficient proportion of land area and a large amount of engineering work, and it cannot be fully applicable to all scenarios. (2) The plant absorption method is to plant aquatic plants in the path through which the farmland return water flows (such as ditches, ponds, etc.), and the harvested plants are prepared into organic fertilizers or carbonized and returned to the field. The plant absorption method has the effect of beautifying the environment at the same time, but its digestion efficiency is still limited, it is highly sensitive to temperature and season, and it is very dependent on artificial management. (3) The filler adsorption method is to use high-adsorption rate and slow-release fillers to be arranged at the checkpoints through which the farmland return water flows, and the fillers after adsorption saturation are directly returned to the field as slow-release fertilizers. Nowadays, many adsorption fillers have been developed, and the upper limit of the adsorption capacity has been continuously broken through. The advantage of the filler adsorption method is that it is not limited by temperature and season and is easy to maintain, only requiring the replacement of fillers. The disadvantage is that the price of the fillers themselves is relatively high, so the cost of replacing fillers is also relatively high. At the same time, direct return to the field may also cause secondary pollution, thereby further increasing the pollution control cost. Summary of the Invention

[0004] The purpose of the present invention is to provide a precise control system for farmland non-point source phosphorus pollution based on enrichment and reuse and its control method, so as to solve the deficiencies existing in the above prior art.

[0005] To achieve the above object, the technical solution of the present invention is as follows: A precise treatment system for farmland non-point source phosphorus pollution based on enrichment and reuse, comprising: A water control unit, a purification unit, a desorption unit and a power supply unit; The purification unit is installed in the water control unit, and the water control unit is externally connected to the desorption unit; The water control unit is used for the water flow control of the system; The purification unit is used for purifying farmland non-point source polluted water. The purification unit includes a directional phosphorus adsorption matrix filler, and the directional phosphorus adsorption matrix filler is a lanthanum-based coated molecular sphere and a lanthanum-based coated molecular brick; The desorption unit is used for desorbing when the phosphorus adsorption capacity of the purification unit is saturated; The power supply unit is used for powering the system.

[0006] Furthermore, the water control unit includes a container, a sliding drainage valve, an irrigation valve, a wireless data collector and a phosphorus concentration identification sensor. The sliding drainage valve and the irrigation valve are installed at the front and rear ends of the drainage water flow direction of the container. The wireless data collector is arranged outside the irrigation valve, and the lower end is connected to the phosphorus concentration identification sensor, and the phosphorus concentration identification sensor is inserted into the drainage.

[0007] Furthermore, a partition is provided inside the container. The partition divides the container into an upper half and a lower half, and the volume ratio range of the upper half to the lower half is 1:1 to 2:1. The directional phosphorus adsorption matrix filler is arranged in the upper half of the container. The position of the partition and the bottom of the container are both provided with clamping points for sliding limit of the sliding drainage valve, and the area ratio of the sliding drainage valve to the irrigation valve is 1:2.

[0008] Furthermore, the desorption unit includes a desorption liquid container, desorption liquid and a flushing pump. The desorption liquid container is filled with desorption liquid and is externally connected to the flushing pump. The flushing pump is inserted outside the irrigation valve through a pipeline.

[0009] Furthermore, the directional phosphorus adsorption matrix filler includes a lanthanum-based coated molecular sphere and a lanthanum-based coated molecular brick. Lanthanum-based coated molecular bricks are arranged on both sides of the lanthanum-based coated molecular sphere, and the total volume ratio of the lanthanum-based coated molecular sphere to the lanthanum-based coated molecular brick is 2:1.

[0010] Furthermore, the power supply unit adopts a solar panel, and the solar panel is installed above the container; the wireless data collector adopts a LORA wireless data collector.

[0011] Furthermore, the flushing pump is a submersible pump with controllable water flow rate, and the rated flow rate is 100-180 m 3 / h.

[0012] Furthermore, the preparation method of the directional phosphorus adsorption matrix filler includes the following steps: Sa. A La(NO3)3·6H2O solution with a configured concentration of 0.4 mol / L, and optionally add an Fe(NO3)3·9H2O solution with a concentration not exceeding 0.4 mol / L; Sb. Put zeolite molecular bricks and zeolite molecular spheres into the solution and stir to fully mix them. The solid-liquid ratio is 0.1 - 1 kg / L. Then gradually add a NaOH solution with a solid-liquid ratio of 0.1 - 2 kg / L and a concentration of 1 mol / L to treat the solution. After standing and impregnating for 8 - 12 h, take it out; Sc. Calcine in a muffle furnace at 200 - 300 °C for 4 - 6 h. After the temperature drops to room temperature, take it out to obtain lanthanum-based coated molecular spheres and lanthanum-based coated molecular bricks.

[0013] Furthermore, the components of the desorbing solution include: Wood vinegar body with a volume fraction of 90% - 98% and a pH value of 3.5 - 5 Potassium chloride solution with a mass fraction of 2% Citric acid solution with a mass fraction of 0.5% - 1%.

[0014] A control method for a precise treatment system of farmland non-point source phosphorus pollution based on enrichment - reuse, including the following steps: S1. Fertile water period S1.1. Operate the water control unit, slide the drainage valve to the lower half of the container, lift the irrigation valve, and the water flow generates an upward flow and enters the purification unit. The directional phosphorus adsorption matrix filler quickly adsorbs phosphorus in the drainage water to complete the purification of fertile water; S1.2. When the phosphorus concentration recognition sensor recognizes that the phosphorus concentration exceeds the limit value, the data is transmitted to the terminal through the wireless data collector to indicate that the adsorption is saturated and desorption is required; S1.3. Slide the drainage valve to the upper half of the container, lower the irrigation valve, and turn on the flushing pump. The desorbing solution is pumped into the container to soak the directional phosphorus adsorption matrix filler; S1.4. After desorption is completed, the flushing pump is connected to the external irrigation structure through a pipeline, turn on the flushing pump, and slide the drainage valve to the lower half of the container for rapid flushing; S1.5. Phosphorus returns to the field along with the desorbing solution, that is, the irrigation water reuse is completed; S2. Non-fertile water period S2.1. Slide the drainage valve to the upper half of the container, lift the irrigation valve, and drain water normally.

[0015] Compared with the prior art, the beneficial effects of the present invention are: (1)The precise treatment system for farmland non-point source phosphorus pollution with enrichment and reuse provided by the present invention, through the scientific structural design of the water control unit, purification unit, desorption unit and energy supply unit, during the period of fertile water and when phosphorus is not saturated, the purification unit adsorbs phosphorus, so as to achieve the purpose of treating pollution; and when the purification unit adsorbs phosphorus to saturation, the desorption unit performs desorption, so as to realize the reuse of the purification unit, and finally rapidly and efficiently remove the phosphorus pollution in the emergency drainage during the fertile water period of farmland in a targeted manner, realizing the precise treatment of agricultural non-point source pollution.

[0016] (2)The purification unit of the present invention adopts a directional adsorption matrix filler, which can be recycled and reused in-situ based on the system structure, significantly improving the service life of the matrix filler. At the same time, the nutrients in the directional adsorption matrix filler can also be recycled, avoiding the risk of secondary pollution caused by directly returning the adsorption matrix filler to the field in the prior art, further reducing the pollution treatment cost, and breaking through the application bottleneck of traditional adsorption fillers in the treatment of farmland non-point source pollution.

[0017] (3)The desorption rate of the desorption liquid configured in the present invention is relatively high. When the phosphorus adsorption capacity of the directional adsorption matrix filler reaches saturation, desorption can be carried out in a timely manner, so as to ensure continuous purification, and the desorption liquid can promote the growth of plants / crops, has no toxic and side effects, and has good environmental protection performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The disclosure of the present invention will be described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes and are not intended to limit the protection scope of the present invention. In the drawings, the same reference numerals are used to refer to the same components. Among them: Figure 1 is the schematic structural diagram of the system of the present invention; Figure 2 is the flow chart of the system control method of the present invention; Figure 3 is the schematic diagram of the effect of Example 2; Figure 4 is the schematic diagram of the effect of Example 3.

[0019] Explanation of the labels in the figure: 1. Container; 2. Sliding drainage valve; 3. Irrigation valve; 4. Wireless data collector; 5. Phosphorus concentration identification sensor; 6. Directional phosphorus adsorption matrix filler; 7. Desorption liquid container; 8. Desorption liquid; 9. Flushing pump; 10. Solar panel; 11. Partition board. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] It is easy to understand that according to the technical solution of the present invention, without changing the essence of the present invention, those of ordinary skill in the art can propose various interchangeable structural ways and implementation ways. Therefore, the following specific embodiments and the accompanying drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as all of the present invention or as a limitation or restriction on the technical solution of the present invention.

[0021] The technical solution of the present application will be described in detail below with reference to the accompanying drawings. The description of the exemplary embodiments is only for the purpose of demonstration, and is by no means a limitation on the present invention and its application or use.

[0022] Example 1

[0023] As Figure 1 shown, a precise treatment system for farmland non-point source phosphorus pollution based on enrichment - reuse includes: A container 1 with a partition 11 inside. The partition 11 divides the container 1 into an upper half and a lower half, and the volume ratio of the upper half to the lower half ranges from 1:1 to 2:1. The directional phosphorus - absorbing matrix filler 6 is arranged in the upper half of the container 1. A sliding drainage valve 2 and an irrigation valve 3 are installed at the front and rear ends of the container 1 in the drainage water flow direction. Card points for sliding limit of the sliding drainage valve 2 are provided at the position of the partition 11 and the bottom of the container 1. The area ratio of the sliding drainage valve 2 to the irrigation valve 3 is 1:2; A wireless data collector 4 is arranged outside the irrigation valve 3, and its lower end is connected to a phosphorus concentration identification sensor 5, and the phosphorus concentration identification sensor 5 is inserted into the drainage.

[0024] A solar panel 10 is respectively connected to the sliding drainage valve 2, the irrigation valve 3, the wireless data collector 4 and the phosphorus concentration identification sensor 5, and is located above the container 1 for providing electric energy for the system.

[0025] The directional phosphorus - absorbing matrix filler 6 is used to purify farmland non - point source polluted water, and includes lanthanum - based coated molecular spheres and lanthanum - based coated molecular bricks; lanthanum - based coated molecular bricks are arranged on both sides of the lanthanum - based coated molecular spheres, and the volume ratio of the lanthanum - based coated molecular spheres to the lanthanum - based coated molecular bricks is 2:1.

[0026] A desorption unit is used for desorption when the phosphorus adsorption capacity of the purification unit is saturated, and includes a desorption liquid container 7, a desorption liquid 8 and a flushing pump 9. The desorption liquid container 7 is filled with the desorption liquid 8 and is externally connected to the flushing pump 9. The flushing pump 9 is inserted into the outside of the irrigation valve 3 through a pipeline; the flushing pump 9 is a submersible pump with controllable water flow rate, and the rated flow rate is 100 - 180 m 3 / h.

[0027] The preparation method of the above - mentioned directional phosphorus - absorbing matrix filler 6 includes the following steps: Sa. Prepare a La(NO3)3·6H2O solution with a concentration of 0.4 mol / L. Additionally, according to specific circumstances, an Fe(NO3)3·9H2O solution with a concentration not exceeding 0.4 mol / L can be optionally added. Sb. Put zeolite molecular bricks and zeolite molecular spheres into the solution and stir to mix them thoroughly. The solid-liquid ratio is 0.1 - 1 kg / L. Then, gradually add a NaOH solution with a solid-liquid ratio of 0.1 - 2 kg / L and a concentration of 1 mol / L to treat the solution. After standing and impregnating for 8 - 12 h, take it out. Sc. Calcine in a muffle furnace at 200 - 300 °C for 4 - 6 h. After the temperature drops to room temperature, take it out to obtain lanthanum-based coated molecular spheres and lanthanum-based coated molecular bricks.

[0028] The desorbing liquid 8 includes the following components: Wood vinegar body with a volume fraction of 90% - 98% and a pH value of 3.5 - 5 Potassium chloride solution with a mass fraction of 2% - 4% Citric acid solution with a mass fraction of 0.5% - 1%.

[0029] Meanwhile, a calcium chloride solution with a mass fraction of 2% - 4% can also be added to the desorbing liquid 8 as needed according to the situation.

[0030] As Figure 2 shown, the control method of the above-mentioned precise farmland non-point source phosphorus pollution treatment system based on enrichment - reuse includes the following steps: S1. Fertile water period S1.1. Operate the water control unit. Slide the drain valve 2 to the lower half of the container 1, and lift the irrigation valve 3. An upward flow of water is generated and enters the purification unit. Then, the directional phosphorus adsorption matrix filler 6 quickly adsorbs phosphorus in the drained water to complete the purification of fertile water. S1.2. When the phosphorus concentration recognition sensor 5 recognizes that the phosphorus concentration exceeds the limit value (this value can be set according to specific usage conditions and requirements), the data is transmitted to the terminal through the wireless data collector 4 to indicate that the adsorption is saturated and desorption is required. S1.3. Slide the drain valve 2 to the upper half of the container 1, lower the irrigation valve 3, and turn on the flushing pump 9. The desorbing liquid 8 is pumped into the container 1 to soak the directional phosphorus adsorption matrix filler 6. S1.4. After desorption is completed, the flushing pump 9 is connected to the external irrigation structure through a pipeline. Turn on the flushing pump 9, and slide the drain valve 2 to the lower half of the container 1 for rapid flushing. S1.5. Phosphorus returns to the field along with the desorbing liquid 8, that is, the irrigation water reuse is completed. S2. Non-fertile water period S2.1. Slide the drain valve 2 to the upper half of the container 1, and lift the irrigation valve 3 for normal drainage.

[0031] Example 2

[0032] The same as Example 1, a precise management system for farmland non-point source phosphorus based on enrichment and reuse and a control method thereof.

[0033] It should be noted that, in this embodiment, the directional phosphorus-absorbing matrix filler 6 includes lanthanum-based coating molecular balls and lanthanum-based coating molecular bricks. A lanthanum-based coating molecular brick is arranged on each side of the lanthanum-based coating molecular ball, and the volume ratio of the lanthanum-based coating molecular ball to the lanthanum-based coating molecular brick is 2:1.

[0034] The preparation method of the directional phosphorus absorbing matrix filler 6 of this embodiment comprises the following steps: Sa, prepare La(NO3)3·6H2O solution with a concentration of 0.4 mol / L; Sb, put zeolite molecular bricks and zeolite molecular balls into the solution and stir to make them fully mixed, the solid-liquid ratio is 1 kg / L, and then gradually add NaOH solution with a solid-liquid ratio of 2 kg / L and a concentration of 1 mol / L to treat the solution, let it stand and soak for 8 hours and then take it out; S5, calcining in a muffle furnace at 200 °C for 4 h, and taking out after the temperature drops to room temperature to obtain lanthanum-based coated molecular balls and lanthanum-based coated molecular bricks, such as Figure 3 (c) in.

[0035] The components of the desorption liquid 8 include: A mixed solution of 2% potassium chloride solution and 1% citric acid solution; like Figure 3 As shown in (a), before desorption, the difference in phosphorus concentration before and after the monitoring system was calculated based on the monitoring results of two actual rainfall events, and the average removal efficiency of phosphorus purification in the rice field fertilizer water generated by precipitation was 78.5%. After desorption, the difference in phosphorus concentration before and after the monitoring system was calculated based on the monitoring results of two actual rainfall events, and the average removal efficiency of phosphorus purification in the rice field fertilizer water generated by precipitation was 53.82%.

[0036] It should be noted that the wireless data collector 4 used in this embodiment is a LORA wireless data collector. When the phosphorus concentration identification sensor 5 identifies that the phosphorus concentration exceeds the preset limit (set to 0.2 mg / L in this embodiment), the data is transmitted to the terminal through the wireless data collector 4 to indicate that the adsorption is saturated and desorption is required. Close the sliding drain valve 2 and the water filling valve 3, turn on the flushing pump 9, so that the desorption liquid 8 (2% KCl solution) in the desorption liquid container 7 flows into the upper space of the container 1 and soaks the directional phosphorus absorption matrix filler 6. Figure 3As shown in (b) therein, with the progress of the desorption time, stage sampling and monitoring were carried out, and the total phosphorus in the desorption liquid 8 was successively 3.8 mg / L (10 min), 3.0 mg / L (30 min), 1.5 mg / L (60 min), 2.5 mg / L (90 min), 3.7 mg / L (120 min), and 3.1 mg / L (120 min). From the above data, it can be seen that the time when the maximum concentration appears is 10 min, which indicates that the 10th min is the optimal desorption time of the 2% KCl + 1% citric acid mixed solution. After the desorption is completed, the flushing pump 9 is connected to the external irrigation structure through a pipeline, and the flushing pump 9 is turned on (the flow rate is adjusted to 100 m 3 / h), the sliding drain valve 2 is slid to the lower half of the container 1, and the desorption liquid 8 is quickly flushed with irrigation water, and the phosphorus element returns to the field along with the desorption liquid 8, that is, the irrigation water reuse is completed.

[0037] Example 3

[0038] Same as Example 1, a precise farmland non-point source phosphorus treatment system based on enrichment-reuse and its control method.

[0039] The preparation method of the directional phosphorus absorption matrix filler 6 in this example includes the following steps: Sa. Prepare a La(NO3)3·6H2O solution with a concentration of 0.4 mol / L, and at the same time add an Fe(NO3)3·9H2O solution with a concentration of 0.4 mol / L; Sb. Put the zeolite molecular bricks and zeolite molecular balls into the solution and stir to make them fully mixed. The solid-liquid ratio is 0.1 kg / L, and then gradually add a NaOH solution with a solid-liquid ratio of 0.1 kg / L and a concentration of 1 mol / L to treat the solution. After standing and impregnating for 12 h, take it out; Sc. Calcine in a muffle furnace at 300 °C for 6 h, take it out after the temperature drops to room temperature, and obtain lanthanum-based coated molecular balls and lanthanum-based coated molecular bricks, as Figure 4 shown in (c) therein.

[0040] The components of the desorption liquid 8 include: A mixed solution made of potassium chloride with a mass fraction of 2% and citric acid with a mass fraction of 0.5%.

[0041] As Figure 4 shown in (a) therein, according to the monitoring results of 2 actual rainfall events, by calculating the difference in phosphorus concentration before and after the monitoring system, the average removal efficiency for the paddy field wastewater generated by precipitation is 55.26%.

[0042] As Figure 4As shown in (b), when the phosphorus concentration identification sensor 5 identifies that the phosphorus concentration exceeds the preset limit value (set to 0.2 mg / L in this embodiment), the data is transmitted to the terminal through the wireless data collector 4 to indicate adsorption saturation and desorption is required. The sliding drainage valve 2 and the irrigation valve 3 are closed, and the built-in valve flushing pump 9 is turned on, so that the desorbing liquid 8 (2% KCl + 1% citric acid solution) in the desorbing liquid container 7 flows into the upper space of the container 1 and soaks the directional phosphorus-adsorbing matrix filler 6. As the desorption time progresses, samples are taken periodically for monitoring, and the total phosphorus in the desorbing liquid 8 is successively 7.2 mg / L (10 min), 4.3 mg / L (30 min), 1.9 mg / L (60 min), 4.2 mg / L (90 min), 5.1 mg / L (120 min), and 4.8 mg / L (120 min), indicating that the 120th minute is the optimal desorption time for the 2% KCl + 0.5% citric acid solution. After desorption is completed, the flushing pump 9 is connected to an external irrigation structure through a pipeline, the flushing pump 9 is turned on (flow rate adjusted to 180 m 3 / h), the sliding drainage valve 2 slides to the lower half of the container 1, and the desorbing liquid 8 is quickly flushed with irrigation water. After the desorbing liquid 8 is flushed, the sliding drainage valve 2 is closed simultaneously to prevent backflow. The phosphorus element is washed into aquatic plants and paddy fields with the desorbing liquid 8 and is successively consumed, that is, the irrigation water reuse is completed.

[0043] After desorption, according to the monitoring results of 2 actual rainfall events, the phosphorus concentration difference before and after the monitoring system is calculated, and the average purification removal efficiency of phosphorus in the paddy field wastewater generated by precipitation is obtained as 51.73%.

[0044] It should be noted that different from the purification efficiency of idealized laboratory similar experiments, when the purification system is actually applied in farmland, it is very difficult to improve the phosphorus purification efficiency due to factors such as the polluted area and uncontrollable outdoor environment. Therefore, the improvement effect of the present invention is actually very significant in practical applications.

[0045] In summary, the technical solution of the present invention can quickly and efficiently remove the phosphorus pollution in the emergency drainage during the paddy field wastewater period in a targeted manner, and effectively avoid the situation of conventional drainage and rainwater consuming the matrix material, realizing the precise treatment of agricultural non-point source phosphorus pollution. At the same time, the in-situ reuse of the matrix filler for multiple rounds is realized, the benefit ratio of the material is improved, the desorbing liquid 8 has a high desorption efficiency, has no toxic or side effects on plants / crops, and improves the utilization efficiency of nutrients.

[0046] The technical scope of the present invention is not limited to the content described above. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A precise treatment system for non-point source phosphorus pollution in farmland based on enrichment and reuse, characterized in that, It includes: a water control unit, a purification unit, a desorption unit and a power supply unit; the purification unit is installed in the water control unit, and the water control unit is externally connected to the desorption unit; the water control unit is used for controlling the water flow of the system; the purification unit is used for purifying agricultural non-point source polluted water. The purification unit includes a phosphorus-directional adsorption matrix filler, and the phosphorus-directional adsorption matrix filler is a lanthanum-based coated molecular sphere and a lanthanum-based coated molecular brick; the desorption unit is used for desorbing when the phosphorus adsorption capacity of the purification unit is saturated; the power supply unit is used for supplying power to the system.

2. The precise treatment system for farmland non-point source phosphorus pollution based on enrichment-reuse according to claim 1, wherein The water control unit includes a container, a sliding drainage valve, an irrigation valve, a wireless data collector and a phosphorus concentration identification sensor. The sliding drainage valve and the irrigation valve are installed at the front and rear ends of the drainage water flow direction of the container. The wireless data collector is arranged outside the irrigation valve, and the lower end is connected to the phosphorus concentration identification sensor, and the phosphorus concentration identification sensor is inserted into the drainage water.

3. The precise farmland non-point source phosphorus pollution treatment system based on enrichment-reuse according to claim 2, characterized in that, A partition is arranged inside the container. The partition divides the container into an upper half and a lower half, and the volume ratio of the upper half to the lower half ranges from 1:1 to 2:

1. The phosphorus-directional adsorption matrix filler is arranged in the upper half of the container. The position of the partition and the bottom of the container are both provided with clamping points for sliding limit of the sliding drainage valve. The area ratio of the sliding drainage valve to the irrigation valve is 1:

2.

4. The precise farmland non-point source phosphorus pollution treatment system based on enrichment-reuse according to claim 3, characterized in that The desorption unit includes a desorption liquid container, desorption liquid and a flushing pump. The desorption liquid container is filled with desorption liquid and is externally connected to the flushing pump. The flushing pump is inserted outside the irrigation valve through a pipeline.

5. The precise treatment system for farmland non-point source phosphorus pollution based on enrichment-reuse according to claim 1, characterized in that The phosphorus-directional adsorption matrix filler includes a lanthanum-based coated molecular sphere and a lanthanum-based coated molecular brick. Lanthanum-based coated molecular bricks are arranged on both sides of the lanthanum-based coated molecular sphere, and the total volume ratio of the lanthanum-based coated molecular sphere to the lanthanum-based coated molecular brick is 2:

1.

6. The precise treatment system for farmland non-point source phosphorus pollution based on enrichment-reuse according to claim 2, wherein The power supply unit adopts a solar panel, and the solar panel is installed above the container; the wireless data collector adopts a LORA wireless data collector.

7. The precise farmland non-point source phosphorus pollution treatment system based on enrichment and reuse according to claim 4, characterized in that, The flushing pump is a submersible pump with controllable water flow rate, and the rated flow rate is 100~180 m 3 / h.

8. The precise treatment system for farmland non-point source phosphorus pollution based on enrichment and reuse according to claim 1, characterized in that, The preparation method of the phosphorus-directional adsorption matrix filler includes the following steps: Sa. Prepare a La(NO3)3·6H2O solution with a concentration of 0.4 mol / L, and optionally add an Fe(NO3)3·9H2O solution with a concentration not exceeding 0.4 mol / L; Sb. Put zeolite molecular bricks and zeolite molecular spheres into the solution and stir to make them fully mixed. The solid-liquid ratio is 0.1-1 kg / L. Then gradually add a NaOH solution with a solid-liquid ratio of 0.1-2 kg / L and a concentration of 1 mol / L to treat the solution. After standing and impregnating for 8-12 h, take it out; Sc. Roast in a muffle furnace at 200-300 °C for 4-6 h. After the temperature drops to room temperature, take it out to obtain the lanthanum-based coated molecular sphere and the lanthanum-based coated molecular brick.

9. The precise treatment system for farmland non-point source phosphorus pollution based on enrichment and reuse according to claim 4, characterized in that, The components of the desorption liquid include: Wood vinegar body, with a volume fraction of 90%-98% and a pH value of 3.5-5 Potassium chloride solution, with a mass fraction of 2% Citric acid solution, with a mass fraction of 0.5%-1%.

10. The control method of the precise treatment system for farmland non-point source phosphorus pollution based on enrichment-reuse according to claim 4, characterized in that, It includes the following steps: S1. Fertile water period S1.

1. Operate the water control unit, slide the drain valve to the lower half of the container, lift the irrigation valve, generate an upward flow of water, and enter the purification unit. The directional phosphorus-adsorbing matrix filler quickly adsorbs phosphorus in the drainage water to complete the purification of the fertilizer-containing water. S1.

2. When the phosphorus concentration recognition sensor recognizes that the phosphorus concentration exceeds the limit value, the data is transmitted to the terminal through the wireless data collector to indicate that the adsorption is saturated and desorption is required. S1.

3. Slide the drain valve to the upper half of the container, lower the irrigation valve, turn on the flushing pump, and the desorbing liquid is pumped into the container to soak the directional phosphorus-adsorbing matrix filler. S1.

4. After the desorption is completed, the flushing pump is connected to the external irrigation structure through a pipeline, the flushing pump is turned on, and the drain valve is slid to the lower half of the container for rapid flushing. S1.

5. The phosphorus returns to the field along with the desorbing liquid, thus completing the reuse of the irrigation water. S2. Non-fertilizer water period S2.

1. Slide the drain valve to the upper half of the container, lift the irrigation valve, and drain water normally.

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