Soil infiltration system for rural domestic sewage treatment and sewage treatment system

Abstract

The invention relates to the field of sewage treatment, in particular to a soil infiltration system for rural domestic sewage treatment and a sewage treatment system. The soil percolation system for rural domestic sewage treatment comprises a multi-stage percolation structure, an electrode and a solar cell panel, and the multi-stage percolation structure comprises a main body, and a first filler layer, a second filler layer and a third filler layer which are sequentially arranged in the main body from top to bottom; modified matrix soil layers are arranged on the upper side of the first filler layer and among the filler layers, positive and negative electrodes of the electrodes are arranged in the first filler layer and the second filler layer respectively, and the modified matrix soil layers are prepared by mixing red soil and modified agricultural and forestry wastes. Under the combined action of the multi-stage percolation structure and the electrodes, the removal of COD, SS, TN, NH3-N and TP in rural domestic sewage by the modified soil percolation system reaches the first-grade A discharge standard in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a soil infiltration device and a sewage treatment system for rural domestic sewage treatment. Background Art

[0002] my country's rapid economic development has led to an improvement in rural living standards and the growth of rural aquaculture, agricultural product processing and other industries. The demand for water and the output of sewage are also increasing day by day. The crude and arbitrary discharge of sewage in the past is no longer suitable for the current economic situation. Therefore, exploring a water treatment system that is suitable for rural sewage is a major research direction in the field of water treatment.

[0003] Initially, rural domestic sewage treatment processes were mostly based on urban or foreign sewage treatment models, such as activated sludge method, A 2 / O technology and biofilm technology require the establishment of huge sewage treatment structures and pipe networks, which are not suitable for the scattered characteristics of rural sewage discharge. Based on the characteristics of scattered rural households, vast land and sparse population, sewage non-powered treatment technology has been developed. However, due to the high personnel management cost and high terrain requirements, there are problems such as poor effluent quality, unstable operation and even inability to operate. With the proposal of coordinated development of environmental protection, economy and ecology, biological and ecological combination technology has been widely used in rural sewage treatment based on its characteristics of no need to build large water treatment structures, convenient application and low cost. At present, the commonly used biological and ecological combination water treatment technologies include stabilization ponds, anaerobic biogas tanks, artificial wetlands, earthworm ecological filter pools, soil infiltration, farmland drainage and emission reduction. However, stabilization ponds and artificial wetlands have the problems of large land occupation, treatment efficiency is easily affected by climate and treatment effect is not ideal; anaerobic biogas tanks have the characteristics of substandard water quality, the need to increase explosion-proof design and easy to produce secondary pollution, which are not suitable for widespread application. The soil infiltration system has been paid attention to in the treatment of rural domestic sewage in recent years due to its small land occupation and simple process. The soil infiltration system is an artificially enhanced sewage ecological treatment technology that uses microorganisms, plant roots and the physical and chemical properties of the soil in the surface soil to purify sewage.

[0004] However, the existing traditional soil infiltration system has the defects of single structure, poor denitrification effect, low treatment load, poor air permeability, easy clogging of fillers, and low water treatment efficiency. Therefore, it is of great significance to develop a soil infiltration system for the characteristics of dispersed discharge, small discharge volume and inconvenience of centralized treatment of rural domestic sewage in my country. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a soil infiltration system for rural domestic sewage treatment, which has low construction and operation costs and can efficiently remove nitrogen and phosphorus.

[0006] The present invention provides a soil infiltration system for rural domestic sewage treatment, comprising a plurality of multi-stage infiltration structures, electrodes and solar panels, wherein the plurality of multi-stage infiltration structures are connected in parallel, and the multi-stage infiltration structure comprises a main body, a first filler layer, a second filler layer, a third filler layer, a modified matrix soil layer and a W-shaped partition; the modified matrix soil layer is a mixture of red soil and modified agricultural and forestry waste; the filler of the first filler layer is a mixture of fly ash and zeolite, the filler of the second filler layer is a mixture of biological ceramsite and sponge iron, and the filler of the third filler layer is activated carbon; the W-shaped partition is a W-shaped ceramic membrane plate with a plurality of holes distributed thereon; The first filler layer, the second filler layer and the third filler layer are sequentially arranged in the main body from top to bottom; the modified matrix soil layer is arranged on the upper side of the first filler layer, and the modified matrix soil layer is arranged between the first filler layer, the second filler layer and the third filler layer, and the W-shaped partition separates each filler layer from the modified matrix soil layer; there is a gap between the third filler layer and the bottom of the main body; the electrode includes a positive electrode and a negative electrode, the positive electrode is arranged in the first filler layer, the negative electrode is arranged in the second filler layer, a battery is connected between the positive electrode and the negative electrode, and the battery is electrically connected to the solar cell panel.

[0007] Specifically, the modified matrix soil layer disposed on the upper side of the first filler layer is formed by mixing red soil and modified agricultural and forestry waste in a mass ratio of (2-3):1.

[0008] Specifically, the mass ratio between the red soil and the modified agricultural and forestry waste in the modified matrix soil layer arranged between the first filler layer, the second filler layer and the third filler layer is 1:(1-2).

[0009] Specifically, water plantain, vetiver, water spinach or water celery are planted on the modified matrix soil layer (6) arranged on the upper side of the first filler layer.

[0010] Specifically, the modified agricultural and forestry waste is at least one of walnut shells, macadamia shells, coffee shells, and fungus matrix, which is obtained by carbonization modification or potassium silicate solution modification.

[0011] Specifically, the carbonization modification is to burn the agricultural and forestry waste at 500-700°C without oxygen or in the absence of oxygen, keep the temperature for 2 hours after reaching the set temperature, and then cool it down at a cooling rate of 10°C / min for 0.5 hours. The anoxic in the present invention means that the volume proportion of oxygen in the reactor is less than 10%.

[0012] Specifically, the potassium silicate solution modification is to chop the forest waste into pieces of 1 mm to 5 mm, and soak them in a potassium silicate solution with a concentration of 10 to 20 mg / L for 24 hours.

[0013] Specifically, the soil infiltration system also includes a water distribution structure arranged on the upper side of the main body, the water distribution structure is composed of a branch-like water distribution pipe or a spherical water distribution structure, and a power device. The branch-like water distribution pipe has multiple rows of holes distributed on the filler side, and the power device drives the mesh water distribution pipe to rotate.

[0014] Specifically, the power device drives the mesh water distribution pipe to rotate at a speed of 10-50rpm.

[0015] Specifically, the spherical water distribution structure is a hollow sphere with a plurality of water outlet holes distributed on the sphere. The spherical water distribution structure is connected to a power device and can rotate when driven by the power device, thereby achieving uniform water distribution.

[0016] Specifically, the thickness of the first filler layer is 10-20 cm; the volume ratio of the first filler layer is 1:(3-5); the particle size of the fly ash is 0.08-0.1 mm, and the particle size of the zeolite is 1-10 mm for the fly ash and zeolite.

[0017] Specifically, the thickness of the second filler layer is 25-50 cm; the volume ratio of the bio-ceramsite to the sponge iron in the second filler layer is (2-3):1; the particle size of the bio-ceramsite is 5-20 mm, and the particle size of the sponge iron is 0.15-0.20 mm.

[0018] Specifically, the thickness of the third filler layer is 45-65 cm; the particle size of the activated carbon in the third filler layer is 0.28-0.42 mm.

[0019] Specifically, the power device is electrically connected to the solar panel (17) and is powered by the solar panel.

[0020] The second aspect of the present invention also provides a sewage treatment system, which includes a sewage pre-sedimentation tank, a pump, a water inlet system and the soil infiltration system for treating rural domestic sewage. The sewage pre-sedimentation tank is connected to the kitchen sink outlet and the septic tank outlet through pipes respectively, and is used for pre-sedimentation treatment of rural domestic sewage. The water inlet system is an inlet pipe and a check valve. The sewage pre-sedimentation tank is connected to the pump and the soil infiltration system in sequence through the water inlet system.

[0021] The present invention provides a soil infiltration system for treating rural domestic sewage, which uses multi-level infiltration layers with different functions to treat rural domestic sewage. The first filler layer is made of fly ash and zeolite. The fly ash has strong adsorption performance and can adsorb SS, N and P in sewage. Zeolite can not only adsorb SS due to its porous structure, but also the cations in it can exchange with N in sewage to remove N efficiently. The first filler layer composed of small-particle fly ash and large-particle zeolite in a volume ratio of 1: (3-5) achieves the best balance between water flow and adsorption, forming a good aerobic environment. The W-shaped partition not only plays the role of supporting the filler layer, but also increases the contact area between the filler layer and the soil infiltration layer due to its W-shaped design, so that microorganisms in the soil, such as nitrifying bacteria, can attach to the filler layer through the gaps. Soil infiltration layers are arranged between the filler layers, which provide more channels for microorganisms in the soil to enter the filler layer, and form granular sludge on the filler surface, further improving the removal rate of N in sewage. The second packing layer is made of a mixture of biological ceramsite and sponge iron. The microporous structure of biological ceramsite has a strong adsorption capacity and can effectively adsorb organic matter and heavy metals in sewage. Sponge iron has a specific adsorption for P and can remove heavy metal ions in water, which plays a role in improving water quality. Due to the use of biological ceramsite and sponge iron, an anaerobic environment is provided, which provides a good habitat for anaerobic bacteria in the soil. The third packing layer uses activated carbon to deeply purify the sewage treated by other packing layers and soil infiltration system, further improving the effluent quality. At the same time, adding electrodes to the first packing layer and the second packing layer effectively improves the migration ability of pollutants. The metal ions generated by electrochemical reactions can flocculate with pollutants in sewage, and the charge on the electrode surface can also adsorb charged ions in sewage; the addition of electrodes greatly improves the efficiency and effect of sewage treatment. The modified soil infiltration layer is made of local agricultural and forestry waste, such as walnut shells, macadamia shells, coffee shells, and fungal matrix, and is made by carbonization modification or potassium silicate solution modification. On the one hand, the modified agricultural and forestry waste is added to the red soil as a soil conditioner, which can improve the soil structure, increase the porosity of the soil, and facilitate sewage infiltration. On the one hand, it can fix the heavy metals in the sewage flowing through the soil. At the same time, various nutrients in the agricultural and forestry waste stimulate the bacterial activity in the soil. Planting plants such as water scallion, vetiver, water spinach or water celery in the upper modified soil matrix layer is not only beautiful, but also can further absorb heavy metals in sewage. Under the reasonable setting of the soil infiltration device of the present invention, the synergistic effect between each filler layer and the soil infiltration layer, coupled with the use of electrodes, greatly improves the treatment effect of rural sewage.

[0022] The sewage treatment system of the present invention removes large particle impurities in rural domestic sewage by arranging a sewage pre-sedimentation tank before the soil infiltration system, thereby reducing the probability of blockage of the soil infiltration system and prolonging the service life of the soil infiltration device.

[0023] The soil infiltration system and sewage treatment system for rural domestic sewage treatment provided by the present invention have the following beneficial effects compared with the prior art:

[0024] (1) Strong applicability: The soil infiltration system of the present invention can be applied to each household in rural areas and can also be applied to centralized treatment facilities.

[0025] (2) Excellent water treatment effect: The soil infiltration device composed of three layers of filler, three layers of soil infiltration and W-shaped baffles not only provides a habitat for bacteria in the soil and is conducive to the formation of granular sludge; combined with the reasonable selection and proportion of each layer of filler, it provides a more suitable sewage hydraulic retention time, taking into account both water treatment capacity and treatment effect; coupled with the electrochemical synergistic treatment effect of the electrode, it greatly improves the effect and efficiency of water treatment.

[0026] (3) Low cost: The soil infiltration layer is made of local materials, and the construction cost is low; the batteries of the water distribution device and the electrodes can provide electricity through solar panels, which rationally utilizes rural energy and reduces operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of soil infiltration structure;

[0028] Figure 2 It is a schematic diagram of a W-type partition ceramic partition;

[0029] Figure 3 It is a schematic diagram of branch-shaped water distribution pipes;

[0030] Figure 4 This is the process flow diagram of the water treatment system.

[0031] Among them, 1-main body, 2-branch water distribution pipe, 3-first packing layer, 4-second packing layer, 5-third packing layer, 6-modified matrix soil layer, 7-sewage pre-sedimentation tank, 8-pump, 9-water inlet system, 11-positive electrode, 12-negative electrode, 13-W-type partition, 14-battery, 15-water inlet, 16-water outlet, 17 solar panel, 18-check valve, 19-kitchen, 20-bathroom. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0033] The embodiment of the present invention solves the problems of easy blockage and poor water treatment effect of the soil infiltration system in the prior art by providing a soil infiltration device and a water treatment system for rural domestic sewage treatment.

[0034] like Figure 1 As shown, the technical solution of the present invention provides a soil infiltration system for rural domestic sewage treatment, including a branch-shaped water distribution pipe 2 (specific structure as shown in Figure 3 As shown in FIG. 1 ), a positive electrode 11 and a negative electrode 12 are provided. The multi-stage infiltration structure includes a main body 1, a first filler layer 3, a second filler layer 4, a third filler layer 5, a modified matrix soil layer 6, a W-shaped separator 13 (the specific structure is as shown in FIG. 1 ). Figure 2 As shown). Four multi-stage infiltration structures are arranged in parallel, the main body 1 is a hollow structure with a bottom, the branch-shaped water distribution pipe 3 is arranged at the upper end of the main body 1 and is electrically connected to the solar cell panel, the first packing layer 3, the second packing layer 4, and the third packing layer 5 are arranged in the main body 1 from top to bottom in sequence, the modified matrix soil layer 6 is arranged on the upper side of the first packing layer 3, the branch-shaped water distribution pipe 2 is arranged above the multi-stage infiltration structure at a certain distance (10-15cm) therefrom, the modified matrix soil layer 6 is arranged between the first packing layer 3 and the second packing layer 4, and the modified matrix soil layer 6 is arranged between the second packing layer 4 and the third packing layer 5, and each layer is supported by a W-shaped partition 13. The third packing layer 5 is at a certain distance (5-10cm) from the bottom of the main body 1, the water inlet 15 is arranged on the upper part of the main body 1, and the water outlet 16 is arranged at the bottom of the main body 1. The positive electrode 11 is arranged in the first packing layer 3, the negative electrode 12 is arranged in the second packing layer 4, and the positive and negative electrodes are connected to the external power battery through wires.

[0035] The thickness of the modified matrix soil layer (6) arranged above the first filler layer is 25 cm, and the thickness of the modified matrix soil layer (6) arranged between the filler layers is 15 cm.

[0036] The first packing layer 3 is 20 cm thick, and contains a filler with a volume ratio of fly ash to zeolite of 1:5, a fly ash particle size of 0.1 mm, and a zeolite particle size of 10 mm. The second packing layer 4 is 50 cm thick, and contains a filler with a volume ratio of bioceramsite to sponge iron of 3:1, a bioceramsite particle size of 20 mm, and a sponge iron particle size of 0.2 mm. The third packing layer 5 is 65 cm high, and contains an activated carbon filler with a particle size of 0.28 mm.

[0037] The modified soil matrix layer 6 is modified by carbonization. The specific method is:

[0038] 1) Modification of agricultural and forestry waste: 3 kg of a mixture of walnut shells and macadamia shells was fired at 600 °C in an oxygen-free environment for 1 h, kept at this temperature for 2 h, and then cooled at a cooling rate of 10 °C / min for 0.5 h to obtain modified agricultural and forestry waste;

[0039] 2) Preparation of modified soil matrix: The modified agricultural and forestry waste was mixed with red soil in a volume ratio of 1:1 to prepare a modified soil matrix.

[0040] In another embodiment, the modified soil matrix layer 6 is modified by potassium silicate sol. The specific method is:

[0041] 1) Modification of agricultural and forestry wastes: 1 kg of a mixture of coffee husks and fungus substrates was taken, the mixture was crushed to a particle size of 3 mm, 2 L of a potassium silicate solution with a concentration of 15 mg / L was prepared, and the crushed mixture was soaked in the potassium silicate solution for 24 hours.

[0042] 2) Preparation of modified soil matrix: The agricultural and forestry waste modified in step 1) is mixed with red soil in a volume ratio of 1:1 to prepare a modified soil matrix.

[0043] The technical solution of the present invention also provides a sewage treatment system, which includes the above-mentioned soil infiltration system, a peristaltic pump 8, a water inlet pipe, a check valve 18 and a sewage pre-sedimentation tank 7. The water inlet of the sewage pre-sedimentation tank 7 is connected to the kitchen sink outlet and the septic tank outlet through pipes, and the water outlet of the sewage pre-sedimentation tank is connected to the water inlets 15 of four soil infiltration devices through pipes, peristaltic pumps 8 and check valves 10.

[0044] Rural domestic sewage flows into the sewage pre-precipitation tank 7 through a pipeline or is directly poured into the sewage pre-precipitation tank 7 for pre-precipitation to remove large impurities. Flocculants and the like can also be added to the sewage pre-precipitation tank 7. The peristaltic pump 8 sucks the upper liquid of the sewage pre-precipitation tank 7 into the branch-shaped water distribution pipe 2; the branch-shaped water distribution pipe 2 is driven by the power of the solar panel to evenly sprinkle the sewage on the modified matrix soil layer 6 on the upper side of the first filler layer. The sewage passes through the first filler layer 3, the second filler layer 4, the third filler layer 5 and the modified matrix soil layer 6 between the layers. The pollutants in the sewage are adsorbed and intercepted by the filler and decomposed under the action of microorganisms. Among them, the first filler layer 3 establishes an environment for the growth of aerobic bacteria. After the organic matter in the sewage is taken up by the microorganisms, part of the organic matter is decomposed through their own metabolism, and energy is provided for their own reproduction. A biofilm is formed in the gaps of the filler. In the first filler layer 3, P, COD, and N in the sewage are partially decomposed; SS is adsorbed by the zeolite gap. When sewage flows through the modified matrix soil layer 6 between the first packing layer 3 and the second packing layer 4, the modified matrix soil layer 6 forms an anaerobic environment, and anaerobic bacteria are attached to the surface of the shell made of agricultural and forestry waste, which increases the contact area between anaerobic bacteria and pollutants in sewage and the hydraulic retention time of sewage, so that anaerobic bacteria can degrade pollutants more fully. At the same time, red soil has specific adsorption properties and has excellent adsorption properties for oil and fat substances in sewage, and then undergoes decomposition and metabolism by microorganisms in red soil. When sewage flows through the second packing layer 4, it is still an anaerobic environment. Sponge iron adsorbs P, and anaerobic bacteria adsorbed in this area further decompose BOD, COD, and N, thereby controlling sludge generation and extending the service life of the system. At the same time, adding electrodes to the first packing layer and the second packing layer effectively improves the migration ability of pollutants. The metal ions generated by the electrochemical reaction can flocculate with the pollutants in the sewage, and the charge on the electrode surface can also adsorb the charged ions in the sewage; the addition of electrodes greatly improves the efficiency and effect of sewage treatment. The remaining N in the sewage is further decomposed by the modified matrix soil layer 6 between the second packing layer 4 and the third packing layer 5. Finally, the sewage is adsorbed and filtered by the activated carbon in the third filler layer 5, and the treated water is discharged through the outlet pipe at the bottom of the main body 1, which can directly seep into the ground to replenish groundwater, or be collected for flushing toilets.

[0045] After domestic sewage discharged from a rural household in Kunming City was connected to the sewage treatment system of the present invention and operated for 30 days, the effluent water quality was tested, and the test results were COD=15mg / L, TN=12mg / L, TP=0.5mg / L, SS=0mg / L, NH3-N=3mg / L, and fecal coliform count=0 / L; it met the Class A emission standard in the national standard "Pollutant Discharge Standard for Urban Sewage Treatment Plants" (GB18918-2002).

[0046] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A soil infiltration system for rural domestic sewage treatment, characterized in that: The invention comprises a plurality of multi-stage infiltration structures, electrodes and solar cell panels (17), wherein the plurality of multi-stage infiltration structures are connected in parallel, and the multi-stage infiltration structures comprise a main body (1), a first filler layer (3), a second filler layer (4), a third filler layer (5), a modified matrix soil layer (6) and a W-shaped partition (13); the modified matrix soil layer (6) is a mixture of red soil and modified agricultural and forestry waste; the filler of the first filler layer (3) is a mixture of fly ash and zeolite, the filler of the second filler layer (4) is a mixture of biological ceramsite and sponge iron, and the filler of the third filler layer (5) is activated carbon; the W-shaped partition (13) is a W-shaped ceramic membrane plate with a plurality of holes; the first filler layer (3), the second filler layer (4) and the third filler layer (5) are sequentially arranged from top to bottom in the main body (1). The modified matrix soil layer (6) is arranged on the upper side of the first filler layer (3), and the modified matrix soil layer (6) is arranged between the first filler layer (3), the second filler layer (4) and the third filler layer (5); the W-shaped partition (13) separates each filler layer from the modified matrix soil layer; there is a gap between the third filler layer (5) and the bottom of the main body (1); the electrodes include a positive electrode (11) and a negative electrode (12), the positive electrode (11) is arranged in the first filler layer (3), the negative electrode is arranged in the second filler layer (4), and a storage battery (14) is connected between the positive electrode (11) and the negative electrode (12); the storage battery (14) is electrically connected to the solar cell panel (17).

2. The soil infiltration system for rural domestic sewage treatment according to claim 1 is characterized in that: The modified matrix soil layer (6) arranged on the upper side of the first filler layer (3) is composed of red soil and modified agricultural and forestry waste mixed in a mass ratio of (2-3):1; the mass ratio of red soil and modified agricultural and forestry waste in the modified matrix soil layer (6) arranged between the first filler layer (3), the second filler layer (4) and the third filler layer (5) is 1:(1-2); the modified matrix soil layer (6) arranged on the upper side of the first filler layer is used to plant water scallion, vetiver, water spinach or water celery.

3. The soil infiltration system for rural domestic sewage treatment according to claim 1 is characterized in that: The modified agricultural and forestry waste is at least one of walnut shells, macadamia shells, coffee shells, and fungus matrix, which is modified by carbonization or potassium silicate solution.

4. The soil infiltration system for rural domestic sewage treatment according to claim 3 is characterized in that: The carbonization modification specifically includes sintering the agricultural and forestry waste at 500-700°C without oxygen or in the absence of oxygen, keeping the temperature for 2 hours after reaching the set temperature, and then cooling it at a cooling rate of 10°C / min for 0.5 hours; the potassium silicate solution modification specifically includes crushing the forestry waste into a particle size of 1mm-5mm, and soaking it in a potassium silicate solution with a concentration of 10-20mg / L for 24 hours.

5. The soil infiltration system for rural domestic sewage treatment according to claim 1 is characterized in that: It also includes a water distribution structure arranged on the upper side of the main body (1), the water distribution structure consisting of a plurality of branch-shaped water distribution pipes (2) or a spherical water distribution structure and a power device, the branch-shaped water distribution pipes (2) are provided with a plurality of rows of holes facing the filler side, the power device drives the mesh water distribution pipes to rotate at a speed of 10-50 rpm; the power device is electrically connected to the solar cell panel (17).

6. The soil infiltration system for rural domestic sewage treatment according to claim 1 is characterized in that: The thickness of the first filler layer (3) is 10-20 cm; the volume ratio of fly ash to zeolite in the first filler layer (3) is 1:(3-5); the particle size of the fly ash is 0.08-0.1 mm, and the particle size of the zeolite is 1-10 mm.

7. The soil infiltration system for rural domestic sewage treatment according to claim 1 is characterized in that: The thickness of the second filler layer (4) is 25-50 cm; the volume ratio of the bio-ceramsite to the sponge iron in the second filler layer (4) is (2-3):1; the particle size of the bio-ceramsite is 5-20 mm, and the particle size of the sponge iron is 0.15-0.20 mm.

8. The soil infiltration system for rural domestic sewage treatment according to claim 1 is characterized in that: The thickness of the third filler layer (5) is 45-65 cm; the particle size of the activated carbon in the third filler layer (5) is 0.28-0.42 mm.

9. The soil infiltration system for rural domestic sewage treatment according to claim 1, characterized in that: The thickness of the modified matrix soil layer (6) disposed on the upper side of the first filler layer (3) is 20-30 cm; the thickness of the modified matrix soil layer (6) between the first filler layer (3), the second filler layer (4) and the third filler layer (5) is 15-20 cm.

10. A sewage treatment system, characterized in that: A soil infiltration system for rural domestic sewage treatment comprising the soil infiltration system according to any one of claims 1 to 9, further comprising a sewage pre-sedimentation tank (7), a pump (8), and a water inlet system (9), wherein a stirring device is arranged on the upper part of the sewage pre-sedimentation tank (7), and the sewage pre-sedimentation tank (7) is connected to a kitchen (19) sink outlet and a toilet (20) septic tank outlet through pipelines, respectively, for pre-sedimentation treatment of rural domestic sewage, and the water inlet system (9) comprises a water inlet pipe and a check valve (18), and the sewage pre-sedimentation tank (7) is connected to the pump (9) and the soil infiltration system in sequence through the water inlet system (9).

Images