Rural landscape-type nitrogen and phosphorus ecological interception ditch system and farmland drainage nitrogen and phosphorus interception method using the same

Patent metadata

Field	Value
Publication number	US-11352279-B2
Application number	US-201916957107-A
Country	US
Kind code	B2
Filing date	Sep 18, 2019
Priority date	Dec 4, 2018
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

A rural landscape-type nitrogen and phosphorus ecological interception ditch system and a farmland drainage nitrogen and phosphorus interception method using the system are provided. The system includes a sediment buffer zone, an ecological ditch unit, an interception-conversion pool and a field ridge hedge fence; the sediment buffer zone, the ecological ditch unit, and the interception-conversion pool are sequentially arranged in a continuous ditch along a direction of a water flow; and the field ridge hedge fence is arranged on field ridges on one side or both sides of the ditch. The present disclosure can, on the basis of not affecting normal production functions of a farmland, further exert an ecological role of the farmland, and use the farmland as an assimilation sink for environmental nitrogen and phosphorus, so as to optimize drainage water quality and improve a farmland ecological environment.

First claim

What is claimed is:

1. A rural landscape-type nitrogen and phosphorus ecological interception ditch system, comprising a sediment buffer zone, an ecological ditch unit, an interception-conversion pool and a field ridge hedge fence, wherein the sediment buffer zone, the ecological ditch unit, and the interception-conversion pool are sequentially arranged in a continuous ditch along a direction of a water flow; and the field ridge hedge fence is provided on field ridges along one or both sides of the ditch;
wherein a downward slope is provided at a front end of the sediment buffer zone along a water inflow direction, to form a water-fall zone, and an end of the water-fall zone is connected to a ditch bottom of the ditch; a buffer flow regulating wall perpendicular to the direction of the water flow is provided downstream of the water-fall zone; and the buffer flow regulating wall spans a cross section of the entire ditch, a plurality of through-flow holes is arranged in the buffer flow regulating wall, and a distribution density of the through-flow holes decreases from top to bottom;
wherein the ecological ditch unit comprises an embedded nitrification-denitrification-dephosphorization complete treatment device and an aquatic plant community unit; the embedded nitrification-denitrification-dephosphorization complete treatment device is embedded in the ditch, for removing nitrogen and phosphorus from farmland drainage; the aquatic plant community unit is provided in the ditch downstream of the embedded nitrification-denitrification-dephosphorization complete treatment device, a slope-protection support is fixed on a side wall of a ditch section where the aquatic plant community unit is located, and support grids are densely arranged on the slope-protection support, for planting emerging plants and submerged plants;
wherein the interception-conversion pool is provided in the embedded ditch, and has a bottom that is lower than the ditch bottom, and a water inlet and a water outlet that are flush with the ditch bottom; an interior of the interception-conversion pool is divided into a catchment area, an adsorption-interception area, and a water storage and drainage area sequentially along the direction of the water flow, a carbon-based filler wall that spans a cross section of a pool body is provided in the adsorption-interception area, and the catchment area—and the water storage and drainage area are separated by the carbon-based filler wall so as not to be directly communicated with each other; a shell of the carbon-based filler wall adopts a porous frame, the porous frame has a hollow interior and a water-permeable outer wall, and in an inner cavity thereof, a water-inflow surface, a water-outflow surface and a bottom are respectively laid with a sponge layer; a cavity between the sponge layers is filled with two layers of different fillers, of which a lower part is a percolation layer and an upper part is a carbon-based adsorption filler layer; and
wherein the field ridge hedge fence is provided on the field ridges along one or both sides of the ditch and a bottom thereof is a pebble zone laid on surfaces of the field ridges, and emerging plants and/or wetland trees and shrubs are planted on the pebble zone.

2. The rural landscape-type nitrogen and phosphorus ecological interception ditch system according to claim 1 , wherein the embedded nitrification-denitrification-dephosphorization complete treatment device has a bottom that is lower than the ditch bottom of the ditch, a water inlet and a water outlet that are flush with the ditch bottom, and a “ ”-shaped water-fall structure formed at a position of the water inlet; a first baffle plate, a second baffle plate, a third baffle plate, and a fourth baffle plate are provided in a tank body of the treatment device, plate surfaces of the four baffle plates are all perpendicular to the direction of the water flow, a flow channel is kept between each baffle plate and a side wall of the device, the flow channels between two adjacent baffle plates and side walls of the device are located on different sides of the device, and an interior of the treatment device forms a “ ”-shaped water flow channel under flow guidance of the four baffle plates; the flow channels at sides of the first baffle plate, the second baffle plate, the third baffle plate, and the fourth baffle plate are provided with a plant growth bag module, an iron-manganese composite oxide film module, a denitrification module, and a phosphorus adsorbing medium module, respectively; the plant growth bag module is composed of ecological concrete and gravel disposed in an ecological bag, and holes for planting emerging plants are provided in a bag body thereof; the iron-manganese composite oxide film module is composed of multi-faceted hollow spheres and gravel disposed in an ecological bag, the multi-faceted hollow spheres being attached with iron-manganese oxide films; the denitrification module is composed of multi-faceted hollow spheres and gravel disposed in an ecological bag, the multi-faceted hollow spheres being attached or filled with a denitrification substrate; and the phosphorus adsorbing medium module is composed of multi-faceted hollow spheres and gravel disposed in an ecological bag, the multi-faceted hollow spheres being attached or filled with a phosphorus adsorbing medium.

3. The rural landscape-type nitrogen and phosphorus ecological interception ditch system according to claim 1 , further comprising a tractor-ploughing road, wherein the tractor-ploughing road is laid along one or both sides of the rural landscape-type nitrogen and phosphorus ecological interception ditch system; and landscape plants are planted along the tractor-ploughing road.

4. The rural landscape-type nitrogen and phosphorus ecological interception ditch system according to claim 1 , wherein a slope of the water-fall zone has a gradient of 1:1-1:2.

5. The rural landscape-type nitrogen and phosphorus ecological interception ditch system according to claim 1 , wherein the buffer flow regulating wall has a thickness of 20-30 cm, a height of two-thirds of a height of the ditch, and a width same as that of the ditch.

6. The rural landscape-type nitrogen and phosphorus ecological interception ditch system according to claim 1 , wherein the slope-protection support is weaved with wicker or crop straw, and side lengths of the support grids are 20-30 cm.

7. The rural landscape-type nitrogen and phosphorus ecological interception ditch system according to claim 1 , wherein a pool volume of the interception-conversion pool is 1.5-3 m 3 , and edges and the bottom of the pool are solidified with cement.

8. The rural landscape-type nitrogen and phosphorus ecological interception ditch system according to claim 1 , wherein the carbon-based filler wall has a thickness of 40-60 cm, a top higher than a top of the ditch, and a width same as that of the ditch; the carbon-based adsorption filler layer is composed of rice husk charcoal having a particle size of 3-5 mm and/or bamboo charcoal having a particle size of 5-10 mm; and the percolation layer is graded gravel having a particle size of 3-5 mm.

9. The rural landscape-type nitrogen and phosphorus ecological interception ditch system according to claim 1 , wherein the pebble zone has a width of 0.3-0.5 m, is laid with pebbles having a particle size of 3-10 cm, and maintains a gradient of 3-10%, and the gradient is inclined to one side of the ditch.

10. A farmland drainage nitrogen and phosphorus interception method using the rural landscape-type nitrogen and phosphorus ecological interception ditch system according to claim 3 , the farmland drainage nitrogen and phosphorus interception method comprising the following s

Assignees

• Univ Zhejiang

Inventors

• Liang Xinqiang
• Zhao Ziyi
• He Shuang
• Liu Feng
• Li Fayong
• Jin Junwei

Classifications

• Y02W10/37

  using solar energy · CPC title

• Y02A40/60

  Ecological corridors or buffer zones · CPC title

• Y02W10/10

  Biological treatment of water, waste water, or sewage · CPC title

• C02F3/308

  Biological phosphorus removal · CPC title

• C02F3/327 Primary

  characterised by animals and plants · CPC title