CN104326552A - Reverse-flow ecological purification tank for irrigated area drainage channels - Google Patents

Abstract

The invention discloses a backflow type ecological purification pool suitable for irrigation ditches, comprising a gate, a backflow inlet channel, a purification pool, a backflow outlet channel, a water diversion wall and an ecological purification box. The purification pool is symmetrically arranged on both sides of the farmland drainage ditch, and communicates with the farmland drainage ditch through the backflow inlet channel and the backflow outlet channel. The gate is installed on the farmland drainage ditch at the entrance of the backflow inlet channel, and a wedge-shaped water dividing wall is set in the center of the drainage ditch on the upstream side of the gate. The purification pool and the backflow outlet channel carry out dynamic circulation to achieve the purpose of multiple purification. The backflow structure adopted in the present invention can significantly prolong the average hydraulic retention time of sewage in the purification tank, improve water purification efficiency, and has the advantages of small footprint, high purification efficiency, simple manufacture, and convenient maintenance, and does not affect farmland drainage The original drainage function of the ditch.

Description

A return-type ecological purification pond suitable for irrigation ditches

technical field

The invention relates to a backflow type ecological purification pond suitable for drainage ditches in irrigation areas, and belongs to the technical field of farmland non-point source control.

Background technique

In agricultural production activities, dissolved or solid pollutants, such as soil particles in farmland, nitrogen, phosphorus, pesticide heavy metals, rural poultry manure and domestic waste, etc. Under the scouring effect of precipitation and runoff, it enters the downstream receiving water body through farmland surface runoff, farmland drainage and underground seepage, thereby causing large-scale water body environmental pollution. The occurrence and diffusion of this kind of pollution is called agricultural non-point source pollution. As a large agricultural production country, my country has experienced rapid development in the scale and level of agricultural production in recent years, and the planting area has increased significantly, resulting in a serious phenomenon of excessive fertilization, which is difficult to reverse quickly in a short period of time. The nitrogen and phosphorus nutrients in the soil are enriched It will continue to become serious, and the potential threat of farmland to water eutrophication will continue unabated. Therefore, agricultural non-point source pollution has become the largest pollution source of river and lake pollution in my country, which has caused serious consequences to ecosystem functions, human health and economic development.

Ecological restoration technology is a method of repairing damaged water bodies using the principles of ecosystems. By establishing the interaction between the water body and the surrounding ecological environment, the ecosystem can realize a virtuous cycle of self-coordination, self-sustainment and self-succession. Researchers from all over the world have conducted a large number of ecological restoration experiments on rivers and lakes with severe eutrophication, fully verifying the effectiveness of ecological restoration. However, most of the current research is mainly focused on the pollution prevention and reduction of pollutant receiving water bodies (such as lakes and reservoirs). Although some treatment effects have been achieved, from the perspective of pollution control, these are all terminal Governance, the source of pollutants cannot be controlled by terminal treatment measures, so it cannot fundamentally solve the problem of water eutrophication. How to control the migration and diffusion of N and P pollutants to the downstream from the source of non-point source pollutants (i.e. farmland irrigation area) will have a multiplier effect on water environment governance, which has important scientific significance and application value.

Farmland drainage ditches are the most common farmland drainage and irrigation facilities in agricultural irrigation areas. The density of the ditch network is high, and the area generally accounts for about 3% of the total land area. The application of ecological resistance control technology in these farmland drainage ditches can effectively reduce the diffusion of pollutants and migration. At present, it is a commonly used ecological resistance control method to set up centralized ecological purification ponds in farmland drainage ditches. Planting aquatic plants in the purification ponds or installing some purification devices, such as biological purification boxes, etc., utilizes the water flow that occurs when the purification device passes through A series of physical and chemical reactions to intercept and reduce the concentration of pollutants. This method can effectively reduce the non-point source pollution caused by the loss of farmland nutrients to downstream water bodies, and the maintenance is relatively simple and convenient, and it is easy to implement. However, it was found in the implementation that the purification efficiency of the purification tank directly depends on the reaction time between the sewage and the purification device. In order to prolong the hydraulic retention time of the sewage in the purification tank, the purification tank needs to have a larger volume to meet the purification requirements, but it takes up a lot of water. It is not suitable to build a large-capacity purification pool on arable land. Therefore, under the premise of ensuring high purification efficiency of the purification pool, reducing the area occupied by the purification pool as much as possible has good practical significance for the promotion and use of ecological purification pools in agricultural non-point source control.

Contents of the invention

The present invention proposes a return-type ecological purification pond suitable for drainage ditches in irrigation areas, which has the advantages of small footprint, long hydraulic retention time, convenient maintenance, and good purification effect. Nutrient water can reduce the pollution of agricultural non-point source pollution to downstream water bodies, and at the same time, it can effectively solve the problem of water blocking in the flood season of the current purification method.

The technical solution of the present invention: includes a gate, a backflow inlet channel, a purification tank, a backflow outlet channel, a water dividing wall, a bypass wall and an ecological purification box; the purification pool, the backflow inlet channel and the backflow outlet channel are all symmetrically set On both sides of the farmland drainage ditch, the purification pool communicates with the farmland drainage ditch through the backflow inlet channel and the backflow outlet channel, the gate is installed on the farmland drainage ditch at the entrance of the backflow inlet channel, and the water dividing wall is arranged upstream of the gate On the center line of the farmland drainage ditch on the side, a bypass wall is set in the middle of the purification pool, and several ecological purification boxes are placed, and the bypass wall is perpendicular to the center line of the farmland drainage ditch.

Both the above-mentioned backflow inlet channel and the backflow outlet channel are opened in the farmland drainage ditch and are connected with the farmland drainage ditch. Connected series structure.

The above-mentioned gate is a two-piece split structure. The water inlet of the backflow inlet channel should be located on the upstream side of the gate. The opening degree of the gate can be adjusted. After the gate is fully opened, the inlet of the backflow inlet channel can be closed.

The above-mentioned water dividing wall is a wedge-shaped structure, the thin-walled end of the water-dividing wall points to the upstream direction of the farmland drainage ditch, and the thick-walled end points to the downstream direction of the farmland drainage ditch.

The above-mentioned ecological purification box is a water-permeable structure, including a net cage cover, biological filler balls, a net cage body and an active carbon filter layer. The biological filler balls are arranged at intervals.

The above-mentioned biological filler ball is made of polyolefin plastic into a hollow spherical shape, and the ball is equipped with biological filler of polyurethane matrix, which is used to absorb pollutants such as N and P in water.

The beneficial effect that the present invention reaches:

1. The present invention adopts a backflow structure, so that the agricultural sewage can be dynamically circulated in the farmland drainage ditch, the backflow inlet canal, the purification tank and the backflow outlet canal, so as to achieve the purpose of multiple purification, and the average retention of sewage in the purification tank The time is 2 to 3 times that of ordinary purification pools, and it has the advantage of good purification effect. At the same time, due to the high utilization efficiency of the purification pool, the area of the purification pool can be appropriately reduced to improve the land utilization rate.

2. The present invention can adjust the water volume and flow speed of backflow by changing the opening degree of the gate, and is suitable for the purification treatment of agricultural sewage under different periods and different drainage flows.

3. During the farmland drainage period, the gate can be fully opened, and the water can be quickly discharged through the gate without affecting the flow capacity of the farmland drainage ditch. At this time, the entrance of the backflow inlet channel will be closed by the gate, and the water will not enter the backflow inlet channel, thereby effectively protecting the ecological purification box in the purification pool from being damaged by the impact of large water flow.

4. The present invention can be rebuilt on the basis of the original farmland drainage gates and channels, with little modification to the original gates and channels, low construction cost and convenient construction.

5. For occasions with heavy pollution, the present invention should be used in series with multiple purification pools to further improve the purification effect.

Description of drawings

Accompanying drawing 1 is the plan view of the present invention (reflux channel is in open state).

Accompanying drawing 2 is the plan view of the present invention (reflux channel is in closed state).

Accompanying drawing 3 is A-A sectional view of Fig. 1.

Accompanying drawing 4 is B-B sectional view of Fig. 1.

Accompanying drawing 5 is the structural diagram of ecological purification box.

In the figure, 1 is the gate, 2 is the return channel, 3 is the diversion wall, 4 is the purification pool, 5 is the bypass wall, 6 is the ecological purification box, 7 is the return channel, 8 is the farmland drainage channel, and 9 is the Water flow direction, 10 is farmland, 11 is the side slope of the canal, 12 is the canal bed, 13 is the water surface in the canal, 14 is the net cage cover, 15 is the biological filler ball, 16 is the net box body, and 17 is the activated carbon filter layer.

detailed description

The technical solutions of the present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

As shown in Fig. 1, Fig. 2, Fig. 3, Fig. 4 and 5, a kind of backflow ecological purification pond suitable for drainage ditches in irrigation districts includes gate 1, backflow inlet canal 2, purification pond 4, backflow outflow canal 7, Dividing wall 3, bypass wall 5 and ecological purification box 6.

The above-mentioned purification pool 4 is symmetrically opened on both sides of the farmland drainage ditch 8, the purification pool 4 is not directly connected with the farmland drainage ditch 8, and a circumventing wall 5 is arranged in the middle of the purification pool 4, and several ecological purification boxes 6 are placed around it. The flow wall 5 is perpendicular to the center line of the farmland drainage ditch 8 . the

The above-mentioned backflow inlet canal 2 and backflow outlet canal 7 are symmetrically opened on both sides of the farmland drainage ditch 8, the backflow inlet canal 2 and the backflow outlet canal 7 are both opened in the farmland drainage ditch 8, and communicated with the farmland drainage ditch 8, and the backflow outlet canal The opening position of 7 is located upstream of the opening position of the backflow inlet channel 2. The backflow inlet channel 2, the purification tank 4 and the backflow outlet channel 7 form an interconnected series structure. Ditch 8 is connected.

The above-mentioned gate 1 is a two-piece structure made of steel, and is installed on the farmland drainage ditch 8 at the water inlet of the backflow water inlet 2 , and the water inlet of the backflow water inlet 2 is located on the upstream side of the gate 1 . The opening degree of the gate 1 is adjustable, and the width of a single gate leaf of the gate 1 is the same as the width of the water inlet of the backflow water channel 2. After the gate 1 is fully opened, the entrance of the backflow water inlet channel 2 can be closed.

The above-mentioned water dividing wall 3 is a wedge-shaped structure, which is poured on the canal bed 12 with reinforced concrete. The water dividing wall 3 is arranged on the upstream side of the gate 1 , on the center line of the farmland drainage ditch 8 , and close to the water inlet of the backflow inlet ditch 2 . The thin-walled end of the water dividing wall 3 points to the upstream direction of the farmland drainage ditch 8 , and the thick-walled end points to the downstream direction of the farmland drainage ditch 8 .

The above-mentioned purification box 6 is a water-permeable structure, as shown in FIG. Above-mentioned net cage cover 14 and net box body 16 adopt PVC pipe and nylon net to make, and net box cover 14 can be opened or closed, and is convenient for the replacement of internal biological filler ball 15 and activated carbon filter layer 17. The above-mentioned biofiller ball 15 is made of polyolefin plastic into a hollow spherical shape, and the ball is equipped with biofiller of polyurethane matrix, which is used to absorb pollutants such as N and P in the water. Biological filler balls 15 are stacked in the cage body 16. The activated carbon filter layer 17 is placed vertically in the cage body 16 and arranged at intervals with the biological filler balls 15 .

Working principle of the present invention:

In daily operation, the gate 1 maintains a certain opening degree, and the water flow in the farmland drainage ditch 8 is divided into two symmetrical left and right paths by the water dividing wall 3 (the water flow direction 9 is shown in Figure 1), and the water flow follows the direction of the water dividing wall 3 Tapered surface flow produces oblique flow velocity. Part of the water flowing through the dividing wall 3 will flow out through the opening of the gate 1 , and another part of the water will flow into the backflow inlet channel 2 . Because the opening degree of the gate 1 is small and the water flow resistance is relatively large, a certain amount of water surface height will be generated on the upstream side of the gate 1. At this time, the water flow resistance in the backflow inlet channel 2 is relatively small, so the water flow flows into the backflow inlet channel 2 more easily. The water flow flows into the purification tank 4 along the backflow inlet channel 2, the purification tank 4 has a certain water capacity, the sewage flows slowly therebetween, and the flow around wall 5 in the purification tank 4 can change the flow path of the sewage in the purification tank 4, It is beneficial for the sufficient physical and chemical reactions between the nutrients in the water and the biofilm in the biofiller ball 15 . The biofilm in the biofiller ball 15 can retain and adsorb easily biodegradable organic substances such as N and P in the agricultural sewage, while the activated carbon filter layer 17 can partially remove heavy metal elements, free chlorine, phenol and other refractory organic substances in the water body, At the same time, it can also filter out algae and some suspended particles in the water body. The water flowing out from the purification pond 4 flows back to the upstream position of the farmland drainage channel 8 through the backflow outlet channel 7, thereby completing a backflow purification process. The water in the farmland drainage ditch 8 will continuously circulate the above-mentioned reflux purification process, thereby effectively prolonging the average hydraulic retention time of the sewage in the purification tank 4 and reducing the concentration of pollutants in the sewage. By changing the opening degree of the gate 1, the amount of backflow water passing through the purification tank 4 can be adjusted to adapt to the changes in the concentration of pollutants and the drainage flow of the farmland drainage ditch 8 in different periods. During the flood season in the irrigation area, the gate 1 can be fully opened to reduce the resistance of the gate to the water flow. At the same time, the entrance of the backflow inlet channel 2 is closed by the gate 1. At this time, the water flow direction 9 is shown in Figure 2. The water flows out quickly through the gate 1 without entering the backflow inlet channel 2, thus avoiding the ecological purification box 6 being impacted by the water flow and causing damage to the biofilm structure, so the ecological purification box 6 does not need to be taken out during the drainage period, which reduces maintenance workload.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (6)

1. A backflow type ecological purification pond applicable to irrigation ditches, is characterized in that: comprise gate, backflow inlet channel, purification pond, backflow outlet canal, water dividing wall, circumvention wall and ecological purification box; Described purification pond The backflow inlet channel and the backflow outlet channel are symmetrically opened on both sides of the farmland drainage ditch. The purification pool is connected with the farmland drainage ditch through the backflow inlet channel and the backflow outlet channel. The gate is installed on the farmland at the entrance of the backflow inlet channel. On the drainage ditch, the water dividing wall is set on the center line of the farmland drainage ditch on the upstream side of the gate, and a bypass wall is set in the middle of the purification pool, and several ecological purification boxes are placed. The bypass wall and the farmland drainage ditch The midline is vertical. 2. A return-type ecological purification pond suitable for drainage ditches in irrigation districts according to claim 1, characterized in that: the return flow inflow canal and the return flow outflow canal are both opened in the farmland drainage ditch and communicated with the farmland drainage ditch , the opening position of the backflow outlet channel is located upstream of the opening position of the backflow inlet channel, and the backflow inlet channel, the purification tank and the backflow outlet channel form an interconnected series structure. 3. A return-type ecological purification tank suitable for irrigation ditches according to claim 1, characterized in that: the gate is a two-piece structure, and the water inlet of the return channel should be located on the upstream side of the gate , the opening degree of the gate is adjustable, and the entrance of the backflow inlet canal can be closed after the gate is fully opened. 4. A kind of backflow type ecological purification pond suitable for drainage ditches in irrigation areas according to claim 1, characterized in that: the water dividing wall is a wedge-shaped structure, and the thin-walled end of the water dividing wall points to the upstream direction of the farmland drainage ditch, The thick-walled end points to the downstream direction of the farmland drainage ditch. 5. A kind of backflow type ecological purification pond suitable for irrigation ditches according to claim 1, characterized in that: the ecological purification box is a water-permeable structure, including a net cage cover, biological filler balls, a net cage body and activated carbon As for the filter layer, the biological filler balls are stacked in the cage, and the activated carbon filter layer is vertically placed in the cage and arranged at intervals with the biological filler balls. 6. A kind of backflow type ecological purification pond suitable for irrigation ditches according to claim 5, characterized in that: the biological filler ball is made of polyolefin plastic hollowed out spherical shape, and the biological filler of polyurethane matrix is housed in the ball, Used to adsorb N, P and other pollutants in water.