CN114716107B

CN114716107B - Underground infiltration system for treating rural domestic sewage and operation method

Info

Publication number: CN114716107B
Application number: CN202210398635.6A
Authority: CN
Inventors: 陈辉伦; 杨朋; 周北海
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2022-04-15
Filing date: 2022-04-15
Publication date: 2023-06-02
Anticipated expiration: 2042-04-15
Also published as: CN114716107A

Abstract

The invention discloses an underground infiltration system for treating rural domestic sewage and an operation method thereof, comprising the following steps: a water inlet tank; the water inlet tank is used for containing domestic sewage; the water inlet tank is communicated with the percolation device through a shunt pipeline; the water outlet tank is used for collecting domestic sewage treated by the percolation device; the infiltration device comprises a vegetation layer and a filling layer; the water outlet box is arranged at the bottom of the filling layer; the vegetation layer is planted on the top of the filling layer. The invention improves the permeability of the matrix by optimizing the filler ratio and the filling mode of the underground infiltration system. The system and the operation method can fully perform the denitrification process in the device and realize the efficient reoxygenation capability of the substrate layer of the device.

Description

Underground infiltration system for treating rural domestic sewage and operation method

Technical Field

The invention relates to the technical field of sewage treatment, in particular to an underground infiltration system for treating rural domestic sewage and an operation method thereof.

Background

In recent years, due to the defects of rural drainage facilities and the lagging awareness of farmer environmental protection, domestic sewage discharged anywhere is converged, so that water pollution around villages is caused. At present, research developed around rural domestic sewage treatment technology at home and abroad mainly comprises a physical and chemical treatment process, an ecological treatment process and a biological treatment process. Wherein, the ecological treatment process mainly utilizes the functions of soil filtration, plant absorption, microbial decomposition and the like to purify and treat sewage. The underground infiltration system is an artificial enhanced ecological treatment process, and is widely applied to rural areas in China due to the characteristics of low operation cost, low energy consumption, good treatment effect and the like.

The underground infiltration system receives pretreated rural domestic sewage and uses a mixed filler consisting of soil and improved materials as a medium for treating and dispersing the sewage. After entering the water distribution area of the system, the sewage is diffused to the periphery under the capillary infiltration and soil infiltration effects, and is purified by utilizing the physical, chemical and biological effects of the soil-plant-microorganism system. The treated water is collected in a water collecting layer, pollutants are trapped in the system, carbon and nitrogen are subjected to a series of aerobic and anaerobic treatments of the system, part of the carbon and nitrogen are converted into inorganic carbon and nitrogen to be stored in soil, part of the inorganic carbon and nitrogen are generated into N2 and CO2 to be dissipated into the air, and phosphorus is adsorbed and converted into sediment in the soil to be removed.

Underground infiltration systems often suffer from poor matrix permeability due to improper packing ratios and packing patterns, which can present a risk of system blockage. In addition, microbial nitrification and denitrification are main ways of denitrification of an underground infiltration system, and denitrification process is often not completely carried out due to lack of a carbon source, so that the denitrification capability of the system is limited.

Disclosure of Invention

The invention aims to provide an underground infiltration system and an operation method for treating rural domestic sewage, so as to solve the problems in the prior art, improve the filler collocation and filling mode of the underground infiltration system and optimize the matrix permeability of the system; optimizing the parameters of the split ratio and the wet-dry ratio, compensating the consumption of carbon sources in the denitrification process of the underground infiltration system, and improving the reoxygenation capacity of the matrix layer of the system.

In order to achieve the above object, the present invention provides the following solutions: the invention provides an underground infiltration system for treating rural domestic sewage, which comprises: a water inlet tank; the water inlet tank is used for accommodating domestic sewage;

a percolation device; the water inlet tank is communicated with the percolation device through a diversion pipeline;

discharging the water tank; the water outlet tank is used for collecting domestic sewage treated by the percolation device;

the infiltration device comprises a vegetation layer and a filling layer; the water outlet tank is arranged at the bottom of the filling layer; the vegetation layer is planted on the top of the filling layer.

The filling layers are filled in a layered manner and comprise a first filling layer, a second filling layer, a third filling layer and a fourth filling layer; the vegetation layer is planted on the first filling layer; the second filling layer and the third filling layer are communicated with a sampler; the water outlet box is arranged at the bottom of the fourth filling layer.

The filler in the first filling layer is red soil; the filler in the second filling layer is 75% red soil and 25% coal cinder; the filler in the third filling layer is 75% of black soil and 25% of coal cinder; the filler of the fourth packing layer is gravel.

The volume ratio of the first filling layer to the second filling layer to the third filling layer to the fourth filling layer is 2:4:3:1.

the split-flow pipeline comprises a three-way valve, a first split-flow pipeline, a second split-flow pipeline and a third split-flow pipeline; the water inlet tank introduces domestic sewage into the third diversion pipeline through a water inlet pump; the first split-flow pipeline, the second split-flow pipeline and the third split-flow pipeline are communicated through the three-way valve; the first shunt pipeline is communicated with the first filling layer; the second shunt tubes are in communication with the third fill layer.

And the three-way valve is also provided with a flowmeter.

The first diversion pipeline extends from the first filling layer to the second filling layer, and a water distributor is arranged at the extending end of the first diversion pipeline;

and the second diversion pipeline and the third filling layer are communicated with a plane, and the sampler is arranged on the plane.

An underground infiltration system operation method A for treating rural domestic sewage fills a filler into the filling layer in a layered manner;

and pumping domestic sewage into the filling layers through the water inlet pump, controlling the water inlet pump to intermittently pump the domestic sewage, and pumping the pumped domestic sewage into the first filling layer and the third filling layer respectively according to different proportions.

The split ratio of the first split pipeline to the second split pipeline is as follows; the intermittent running wet-dry ratio of the water inlet pump is 1:2.

The invention discloses the following technical effects: the invention improves the permeability of the matrix by optimizing the filler ratio and the filling mode of the underground infiltration system. The system and the operation method can fully perform the denitrification process in the device and realize the efficient reoxygenation capability of the substrate layer of the device.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of the overall structure;

FIG. 2 is a schematic diagram of a water distribution plate structure;

FIG. 3 is a top view of a water distribution plate structure;

wherein, 1, a water inlet tank; 2. a water inlet pump; 3. a flow meter; 4. a first split flow conduit; 5. a second split flow conduit; 6. a vegetation layer; 7. a filling layer; 8. a water distributor; 9. a sampler; 10. discharging the water tank; 11. a first filler layer; 12. a second filler layer; 13. a third filler layer; 14. a fourth filler layer; 15. a water inlet pipe; 16. a water distribution plate; 17. a water-buffering tank; 18. reinforcing rib plates.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.

The invention provides an underground infiltration system for treating rural domestic sewage, which comprises: a water inlet tank 1; the water inlet tank 1 is used for containing domestic sewage;

a percolation device; the water inlet tank 1 is communicated with the percolation device through a diversion pipeline;

a water outlet tank 10; the water outlet tank 10 is used for collecting domestic sewage treated by the infiltration device;

the infiltration device comprises a vegetation layer 6 and a filling layer 7; the water outlet tank 10 is arranged at the bottom of the filling layer 7; the vegetation layer 6 is planted on top of the filling layer 7.

The filling layer 7 is filled in a layered manner and comprises a first filling layer 11, a second filling layer 12, a third filling layer 13 and a fourth filling layer 14; the vegetation layer 6 is planted on the first filling layer 11; the second filling layer 12 and the third filling layer 13 are communicated with a sampler 9; the outlet tank 10 is placed at the bottom of the fourth filling layer 14.

The first filling layer 11 is filled with red soil; the second filling layer 12 is filled with 75% of red soil and 25% of coal cinder; the third filling layer 13 is filled with 75% of black soil and 25% of coal cinder; the packing of the fourth pack 14 is gravel.

The volume ratio of the first filling layer 11, the second filling layer 12, the third filling layer 13 and the fourth filling layer 14 is 2:4:3:1.

the split-flow pipeline comprises a three-way valve, a first split-flow pipeline 4, a second split-flow pipeline 5 and a third split-flow pipeline; the water inlet tank 1 introduces domestic sewage into a third split-flow pipeline through the water inlet pump 2; the first diversion pipeline 4, the second diversion pipeline 5 and the third diversion pipeline are communicated through a three-way valve; the first shunt tubes 4 are in communication with the first filling layer 11; the second shunt tubes 5 communicate with the third filler layer 13.

The three-way valve is also provided with a flowmeter 3.

The first diversion pipeline 4 extends from the first filling layer 11 to the second filling layer 12, and the extending end of the first diversion pipeline 4 is provided with a water distributor 8;

the second shunt pipeline 5 is provided with a sampler 9 on the plane communicated with the third filling layer 13.

An underground infiltration system operation method A1 for treating rural domestic sewage fills filler into a filling layer in a layered manner;

domestic sewage is pumped into the filling layer through the water inlet pump, the water inlet pump is controlled to be intermittently pumped, and the pumped domestic sewage is pumped into the first filling layer and the third filling layer respectively according to different proportions.

The split ratio of the first split-flow pipeline 4 to the second split-flow pipeline 5 is 3:1; the wet-dry ratio of the intermittent operation of the water inlet pump 2 is 1:2.

In one embodiment of the invention, the second shunt pipeline 5 is used to supplement the carbon source required for the denitrification region within the packed layer 7.

In one embodiment of the invention, the water distributor 8 is used for realizing the uniform introduction of domestic sewage into the filling layer 7.

In one embodiment of the invention, the vegetation layer 6 is used to absorb nitrogen in domestic sewage.

In one embodiment of the invention, the water distributor 8 comprises a water inlet pipe 15, the top of which is communicated with the second shunt pipeline 5, and one end of the water inlet pipe 15 is communicated with a water distribution disc 16; the water distribution disc 16 is of a regular dodecahedron structure, and arc-shaped fixing plates are filled on every two side walls of the water distribution disc; the arc-shaped fixing plate extends downwards out of the bottom surface of the water distribution plate 16, and the height of the arc-shaped fixing plate is one time of the height of the water distribution plate 16, so that the arc-shaped fixing plate is conveniently fixed in the second filling layer 12.

Further, a communication hole communicated with the water inlet pipe 15 is formed in the center of the water distribution plate 16, and a water-retarding groove 17 is formed in the inner side of the communication hole; the joint of the water inlet pipe 15 and the water distribution disk 16 is positioned above the water delay tank 17;

furthermore, a plurality of reinforcing rib plates 18 are fixedly arranged on the periphery of the water inlet pipe 15 at equal intervals; the bottom of the reinforcement rib 18 is provided with a conduction path communicated with the slow water tank 17.

The water distribution disc 16 and the water storage groove 17 are provided with gaps, the bottom of the reinforcing rib plate 18 is connected with the water inlet pipe 15 and the water storage groove 17, so that water enters the water storage groove 17 through the water inlet pipe 15 during water distribution and flows out of the gaps to uniformly distribute water in multiple directions, meanwhile, when the water quantity is overlarge, the water directly flows out of the conduction passage to distribute water when passing through the gaps between the water inlet pipe 15 and the water storage groove 17, the phenomenon that the water distribution is unbalanced due to the flow rate of the traditional bend water distribution is prevented, the water distribution is increased uniformly, the operation is simple, and the water distribution efficiency is improved.

1) Experimental device and operating conditions

The filling layer 7 is cylindrical, the diameter of the bottom surface is 15cm, and the height is 100cm. Coal cinder, red soil, black soil and gravel are mixed according to different proportions and are filled into the filling layer 7 in a layered mode, and manual water distribution is conducted and the device is started. The ambient temperature during operation was 25 ℃. The operation mode is an intermittent operation mode, each period is 36h, and the period is set as follows: and water is fed for 12h, and the water is dropped for 24h. The water inlet mode is split water inlet.

2) Experimental wastewater

The experimental sewage is obtained from pretreated rural domestic sewage, and the quality of inflow water is shown in the following table:

3) Test sampling assay

When the device runs stably, the water sample in and out is sampled once every other day, and COD, total Nitrogen (TN), ammonia nitrogen (NH 4 < + > -N) and Total Phosphorus (TP) are measured after filtration. COD is measured by adopting a potassium dichromate method for water quality detection in national environmental protection Standard of the people's republic of China (HJ 828-2017), and TN, NH4+ -N and TP are measured by adopting a spectrophotometry method. The detection result shows that: after the system stably operates: when the split ratio is 3:1, wet-dry ratio of 1:2, the COD removal rate is 93%, the average concentration of COD in the inflow water is 270.4mg/L, and the average concentration of COD in the outflow water is 19.7mg/L; TN removal rate is 75%, the average concentration of inflow TN is 82.5mg/L, and the average concentration of outflow TN is 20.0mg/L; the removal rate of NH4 < + > -N is 77%, the average concentration of NH4 < + > -N in the inlet water is 79.2mg/L, and the average concentration of NH4 < + > -N in the outlet water is 18.3mg/L; the TP removal rate was 99%, the average concentration of the inlet water TP was 6.2mg/L, and the average concentration of the outlet water TP was about 0.033mg/L.

Further, the wet-to-dry ratio is 1:2 (water inlet 12h: falling dry 24 h); the total water inflow is 1.00ml/min, and the split ratio is 3:1 (first shunt 0.75ml/min, second shunt 0.25 ml/min); the water distributor for the water discharged from the first shunt pipe is positioned at the depth of 50cm of the device, and the water discharged from the second shunt pipe is positioned at the depth of 70cm of the device.

Furthermore, the cost of the filler in the filling layer 7 is greatly reduced, and the rural economic conditions are considered in combination with practice, so that the method is convenient to popularize, economical and practical.

Further, according to the embodiment, the COD removal rate can reach 93%, the TP removal rate can reach 99%, and the TN removal rate can reach 75%; the NH4 < + > -N removal rate can reach 77 percent.

In the description of the present invention, it should be understood that the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the present invention, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.

Claims

1. An underground infiltration system for treating rural domestic sewage, comprising:

a water inlet tank (1); the water inlet tank (1) is used for containing domestic sewage;

a percolation device; the water inlet tank (1) is communicated with the percolation device through a diversion pipeline;

a water outlet tank (10); the water outlet tank (10) is used for collecting domestic sewage treated by the infiltration device;

the percolation device comprises a vegetation layer (6) and a filling layer (7); the water outlet tank (10) is arranged at the bottom of the filling layer (7); the vegetation layer (6) is planted on the top of the filling layer (7);

the filling layers (7) are filled in a layered manner and comprise a first filling layer (11), a second filling layer (12), a third filling layer (13) and a fourth filling layer (14); the vegetation layer (6) is planted on the first filling layer (11); the second filling layer (12) and the third filling layer (13) are communicated with a sampler (9); the water outlet tank (10) is arranged at the bottom of the fourth filling layer (14);

the first filling layer (11) is filled with red soil; the filler in the second filling layer (12) is 75% red soil and 25% coal cinder; the filler in the third filling layer (13) is 75% of black soil and 25% of coal cinder; the filler of the fourth packing layer (14) is gravel;

the volume ratio of the first filling layer (11), the second filling layer (12), the third filling layer (13) and the fourth filling layer (14) is 2:4:3:1, a step of;

the split-flow pipeline comprises a three-way valve, a first split-flow pipeline (5), a second split-flow pipeline (4) and a third split-flow pipeline; the water inlet tank (1) introduces domestic sewage into the third diversion pipeline through a water inlet pump (2); the first diversion pipeline (5), the second diversion pipeline (4) and the third diversion pipeline are communicated through the three-way valve; the first shunt pipeline (5) is communicated with the first filling layer (11); the second shunt pipeline (4) is communicated with the third filling layer (13).

2. An underground infiltration system for treating rural domestic sewage according to claim 1, wherein: and the three-way valve is also provided with a flowmeter (3).

3. An underground infiltration system for treating rural domestic sewage according to claim 1, wherein: the first diversion pipeline (5) extends from the first filling layer (11) to the second filling layer (12), and a water distributor (8) is arranged at the extending tail end of the first diversion pipeline (5); the second diversion pipeline (4) and the third filling layer (13) are communicated with each other, and the sampler (9) is arranged on the plane.

4. A method of operating an underground infiltration system for treating rural domestic sewage, comprising the underground infiltration system for treating rural domestic sewage according to any one of claims 1 to 3, characterized in that:

a1 filling filler into the filling layer in a layered manner;

a2, pumping domestic sewage into the filling layers through the water inlet pump, controlling the water inlet pump to intermittently pump the domestic sewage, and pumping the pumped domestic sewage into the first filling layer and the third filling layer respectively according to different proportions.

5. The method for operating an underground infiltration system for treating rural domestic sewage according to claim 4, wherein: the split ratio of the first split pipeline (4) to the second split pipeline (5) is 3:1; the wet-dry ratio of the intermittent operation of the water inlet pump (2) is 1:2.