Farmland tail water purification system in plain river network area

Abstract

The utility model discloses a plain river network area farmland tail water purification system which comprises a middle ditch used for discharging farmland tail water, a plurality of nitrogen and phosphorus filtering dams used for adsorbing nitrogen and phosphorus are sequentially built in the middle ditch along a flow channel, and gates are arranged on the nitrogen and phosphorus filtering dams. A denitrification dephosphorization device is arranged on the upstream of the nitrogen and phosphorus filter dam at the tail end of the middle ditch, and a water quality detector is arranged at a water outlet at the tail end of the middle ditch. Compared with the prior art, the tail water of the farmland is intercepted in the middle ditch in a segmented mode through the nitrogen and phosphorus filtering dams, water is stored in the rice field steeping period and the fertilization peak period, and therefore the tail water can be pumped back to the farmland again for irrigation, and the nutrient recycling effect is achieved; each nitrogen and phosphorus filter dam can adsorb nitrogen and phosphorus in the corresponding farmland tail water, and the denitrification dephosphorization device can further eliminate nitrogen and phosphorus in the tail water, so that the nitrogen and phosphorus content in the tail water meets the emission requirement.

Description

Technical Field

[0001] The utility model relates to the technical field of water conservancy, and particularly relates to a purification system for farmland tail water in plain river network areas. Background Technique

[0002] Farmland irrigation river networks are important agricultural water conservancy facilities, which provide stable and efficient irrigation water sources for farmland through means such as water diversion, water conveyance, water distribution, and water storage.

[0003] In plain river network areas, most of the drainage in the middle ditches comes from paddy field drainage except for rainfall. Multiple studies at home and abroad have shown that more than 50% of the chemical fertilizers applied in paddy fields are discharged into the middle ditches along with farmland drainage. The nitrogen and phosphorus contents in the tail water are relatively high, causing the concentrations of total nitrogen, total phosphorus, COD, etc. in the water body to rise, resulting in water eutrophication and even more serious pollution problems. Content of the Utility Model

[0004] The main purpose of the utility model is to provide a purification system for farmland tail water in plain river network areas, which reduces agricultural non-point source pollution through the reuse of farmland tail water. On the one hand, it improves the water environment of the area, and on the other hand, it can also save water resources, meeting the requirements of ecological circular agriculture.

[0005] To achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0006] A purification system for farmland tail water in plain river network areas includes a middle ditch for discharging farmland tail water. A number of nitrogen and phosphorus filtration dams for adsorbing nitrogen and phosphorus are successively built along the flow path of the middle ditch. Gates are arranged on the nitrogen and phosphorus filtration dams. An anaerobic phosphorus removal device is arranged upstream of the nitrogen and phosphorus filtration dam at the end of the middle ditch, and a water quality detector is arranged at the drainage outlet at the end of the middle ditch.

[0007] Further, the nitrogen and phosphorus filtration dam includes a trough built with biochar bricks with honeycomb holes, and biochar granular stones are filled in the trough.

[0008] Further, the anaerobic phosphorus removal device includes a wire mesh frame matching the middle ditch, and a nitrogen and phosphorus denitrification agent is filled in the wire mesh frame.

[0009] Further, a water pump station for returning the water in the middle ditch back to the farmland is built upstream of each nitrogen and phosphorus filtration dam.

[0010] Further, an ecological bank protection is arranged on the slope surface of the middle ditch.

[0011] Further, the ecological bank protection includes a frame fixed on the slope surface of the middle ditch. Organic matter is filled in the frame, and water purification plants are planted in the organic matter.

[0012] Further, a support is built between the frame and the bottom of the middle ditch.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] Several nitrogen and phosphorus filtration dams of the utility model intercept the farmland tail water in segments in the middle ditch, store water during the rice paddy flooding period and the fertilization peak period, so that the tail water can be pumped back to the farmland for irrigation again, improving the utilization rate of nitrogen and phosphorus. Moreover, when discharging the tail water, each nitrogen and phosphorus filtration dam can adsorb nitrogen and phosphorus in the corresponding farmland tail water, and the denitrifying phosphorus removal device can further remove nitrogen and phosphorus in the tail water, so that the nitrogen and phosphorus content in the tail water meets the discharge requirements.

[0015] The water-lifting pump station of the utility model is used to return the tail water in the middle ditch to the farmland during the rice paddy flooding period, so as to make full use of nitrogen and phosphorus in the tail water.

[0016] The ecological bank protection of the utility model has a good slope protection effect, thus reducing soil erosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic overall view of a farmland tail water purification system in a plain river network area of the utility model.

[0018] Figure 2 It is a schematic connection view of the middle ditch and the ecological bank protection of a farmland tail water purification system in a plain river network area of the utility model.

[0019] Figure 3 It is a schematic structure view of the nitrogen and phosphorus filtration dam and the gate of a farmland tail water purification system in a plain river network area of the utility model.

[0020] Figure 4 It is a schematic view of the denitrifying phosphorus removal device of a farmland tail water purification system in a plain river network area of the utility model.

[0021] In the figure: 1, middle ditch; 2, ecological bank protection; 201, grid; 202, water purification plants; 203, organic matter; 3, nitrogen and phosphorus filtration dam; 301, gate; 302, biological carbon particle stone; 303, tank body; 4, denitrifying phosphorus removal device; 401, lead wire mesh frame; 402, nitrogen and phosphorus denitrifying agent; 6, water-lifting pump station; 7, water quality detector; 8, support. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] In order to make the technical means, creative features, achieved purposes and functions of the utility model easy to understand, the utility model will be further described below in conjunction with specific embodiments.

[0023] Such as Figures 1-4As shown in the figure, a purification system for farmland tail water in a plain river network area includes a middle ditch 1 for discharging farmland tail water. The bottom of the middle ditch 1 is protected by a 50-cm layer of pebbles or block stones plus volcanic stones. On the one hand, it prevents soil erosion; on the other hand, it adsorbs water pollutants. Along the flow path of the middle ditch 1, several nitrogen and phosphorus filtration dams 3 for adsorbing nitrogen and phosphorus are built in sequence. A gate 301 is set on the nitrogen and phosphorus filtration dam 3. An anaerobic phosphorus removal device 4 is set upstream of the nitrogen and phosphorus filtration dam 3 at the end of the middle ditch 1. A water quality detector 7 is set at the drainage outlet at the end of the middle ditch 1.

[0024] In this embodiment, as Figure 1 shown, several nitrogen and phosphorus filtration dams 3 intercept the farmland tail water in segments in the middle ditch 1. During the rice ponding period and the peak fertilization period, the gate 301 is closed for water storage, which can extend the retention time of the farmland tail water in the area, so that it is convenient for personnel to pump the tail water in the middle ditch 1 back to the farmland for irrigation again, achieving the effect of nutrient reuse. When the tail water needs to be discharged into the outer river, the tail water will first flow from the farmland into the middle ditch 1. Each nitrogen and phosphorus filtration dam 3 corresponds to a corresponding area of farmland. Therefore, when the tail water flows through the nitrogen and phosphorus filtration dam 3, the nitrogen and phosphorus filtration dam 3 can adsorb the nitrogen and phosphorus in the tail water, thereby reducing the nitrogen and phosphorus content in the tail water. And when the tail water is transported to the last nitrogen and phosphorus filtration dam 3, there is an anaerobic phosphorus removal device 4 upstream of this nitrogen and phosphorus filtration dam 3, which can further treat the collected tail water and further reduce the nitrogen and phosphorus content in the tail water. Then, the water quality detector 7 detects whether the nitrogen and phosphorus content in the tail water meets the discharge standard. If it meets the standard, the gate is opened to discharge the tail water into the outer river.

[0025] Among them, as Figure 3 shown, the nitrogen and phosphorus filtration dam 3 includes a trough 303 built with biochar bricks with honeycomb holes. Biochar granular stones 302 are filled in the trough 303. The biochar bricks are processed from volcanic stone powder and biochar powder (such as rice, wheat, and corn biochar powder) into 10-cm×10-cm×20-cm bricks with honeycomb holes. The biochar granular stones 302 are made of volcanic stone powder and biochar powder (such as rice, wheat, and corn biochar powder) processed into granular stones with a particle size of 10 cm - 15 cm, so that the nitrogen and phosphorus filtration dam 3 has a strong adsorption effect on the nitrogen and phosphorus in the tail water, thereby purifying the tail water.

[0026] Among them, as Figure 4 shown, the anaerobic phosphorus removal device 4 includes a wire mesh frame 401 matching the middle ditch 1. Nitrogen and phosphorus denitrifying agent 402 is filled in the wire mesh frame 401. The width of the wire mesh frame 401 is equal to the width of the middle ditch 1. The nitrogen and phosphorus denitrifying agent 402 is in the form of particles with a diameter of 3 cm - 5 cm, which can fully eliminate the nitrogen and phosphorus in the tail water and purify the water quality.

[0027] Among them, as Figure 1As shown in the figure, a water pumping station 6 is built upstream of each nitrogen and phosphorus filtration dam 3. The water pumping station 6 is used to return the water in the middle ditch 1 back to the farmland during the rice paddy flooding period, so as to make full use of the nitrogen and phosphorus in the tail water.

[0028] Among them, as Figure 1 and Figure 2 shown, an ecological revetment 2 is arranged on the slope surface of the middle ditch 1. The ecological revetment 2 includes a grid 201 fixed on the slope surface of the middle ditch 1. The grid 201 is filled with organic matter 203, such as soil. Water purification plants 202, such as reeds, calamus, water onions, and irises, are planted in the organic matter 203 to reduce soil erosion.

[0029] Among them, as Figure 2 shown, a support 8 is built between the grid 201 and the inner bottom of the middle ditch 1. The support 8 can prevent the bottommost grid 201 from hanging in the air, thereby improving the stability of the grid 201.

[0030] Working principle: The farmland tail water is discharged into the middle ditch 1. When it is at the peak period of rice paddy flooding and fertilization, the gate 301 is closed, so that the middle ditch 1 forms multiple areas for water storage, thereby extending the retention time of the farmland tail water in the area. And, the water pumping station 6 is used to transport the tail water accumulated in the middle ditch 1 back to the farmland again, so as to achieve the effect of nutrient reuse. When it is necessary to discharge the tail water into the outer river, the gate 301 is opened. Since each nitrogen and phosphorus filtration dam 3 corresponds to a corresponding area of farmland, when the tail water of the corresponding farmland flows through the corresponding nitrogen and phosphorus filtration dam 3, the nitrogen and phosphorus filtration dam 3 can adsorb the nitrogen and phosphorus in the tail water, thereby reducing the nitrogen and phosphorus content in the tail water. And, when the tail water is transported to the last nitrogen and phosphorus filtration dam 3, there is a denitrifying phosphorus removal device 4 upstream of this nitrogen and phosphorus filtration dam 3, which can treat the collected tail water again and further reduce the nitrogen and phosphorus content in the tail water. Then, the water quality detector 7 is used to detect whether the nitrogen and phosphorus content in the tail water meets the discharge standard. If it meets the standard, the gate is opened to discharge the tail water into the outer river.

[0031] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A farmland tail water purification system in a plain river network area, comprising a middle ditch (1) for discharging farmland tail water, characterized in that: The middle ditch (1) is provided with a plurality of nitrogen-phosphorus filter dams (3) for absorbing nitrogen and phosphorus in sequence along the flow channel, the nitrogen-phosphorus filter dams (3) are provided with gates (301), a denitrification phosphorus removal device (4) is provided upstream of the nitrogen-phosphorus filter dam (3) at the end of the middle ditch (1), and a water quality detector (7) is provided at the drainage outlet at the end of the middle ditch (1).

2. The farmland tailwater purification system in a plain river network area according to claim 1 is characterized by: The nitrogen and phosphorus filtering dam (3) comprises a trough body (303) constructed of biochar bricks with honeycomb holes, and the trough body (303) is filled with biochar granular stones (302).

3. The farmland tailwater purification system in a plain river network area according to claim 1 is characterized by: The denitrification and phosphorus removal device (4) comprises a wire mesh frame (401) matched with the middle ditch (1), and the wire mesh frame (401) is filled with a nitrogen and phosphorus denitrification agent (402).

4. The farmland tailwater purification system in a plain river network area according to claim 1 is characterized by: A water pumping station (6) is built upstream of each of the nitrogen and phosphorus filtering dams (3) to return the water in the middle ditch (1) to the farmland.

5. The farmland tailwater purification system in a plain river network area according to claim 1 is characterized by: The slope surface of the middle ditch (1) is provided with an ecological bank protection (2).

6. The farmland tailwater purification system in a plain river network area according to claim 5 is characterized by: The ecological revetment (2) comprises a frame (201) fixed to the slope surface of the middle ditch (1), the frame (201) is filled with organic matter (203), and water purification plants (202) are planted in the organic matter (203).

7. The farmland tailwater purification system in a plain river network area according to claim 6 is characterized by: A support (8) is constructed between the frame (201) and the inner bottom of the middle groove (1).

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