A rural domestic sewage treatment system
By designing water storage modules and multi-stage percolation modules in rural domestic sewage treatment systems and combining with the aeration system, the problem of poor sewage treatment effect in the existing technology has been solved, and efficient sewage removal and water quality improvement have been achieved.
Patent Information
- Application Number
- CN202111281444.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-11-01
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2041-11-01
AI Technical Summary
The existing rural domestic sewage treatment equipment has problems such as poor harmless effect, poor sanitation conditions, equipment maintenance problems and pollution risks. In particular, the three-format septic tank is poorly effective when running at full or overload, resulting in sewage discharge. The amount increases, forming a black and odorous water body.
A rural domestic sewage treatment system was designed, including a water storage module and a permeability module arranged in sequence from front to back. The permeability module is equipped with a multi-stage permeability layer from thin to coarse, and an aeration system through a quartz gravel layer. The combined structure of limestone gravel layer realizes secondary precipitation and contact oxidation of sewage, and removes impurities, bacteria and pollution indicators.
It effectively improves the harmless treatment effect of domestic sewage, removes impurities, bacteria and pollution indicators, especially the removal rate of total phosphorus, reduces the negative impact of chemical precipitation, and improves treatment efficiency and water quality.
Smart Images
Figure CN113860658B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to domestic sewage treatment, and in particular to a rural domestic sewage treatment system. Background Art
[0002] Most of the existing rural integrated domestic sewage treatment equipment or three-chamber septic tanks are integrated into a single tank body. After installation, they are often left unattended and unmaintained. In addition, the integrated equipment is a customized product, which sometimes makes it difficult to meet the terrain conditions. In addition, the three-chamber septic tanks have problems such as poor harmlessness and poor sanitary conditions. Rural domestic sewage has the characteristics of scattered collection and concentrated discharge periods. After dry toilets are converted to water toilets, the existing three-chamber septic tanks are often operated at full capacity or overload, resulting in poor harmlessness treatment effects, increased sewage discharge, greater pollution, and even the formation of black and smelly water bodies. In order to adapt to local conditions, make the three-chamber septic tanks more efficient, effectively solve the problems of scattered discharge, poor effect, insufficient resource utilization and pollution risks of rural domestic sewage treatment, and effectively solve the problems of rural domestic sewage treatment and operation and maintenance, this system has been specially developed. Summary of the Invention
[0003] The purpose of the present invention is to propose a rural domestic sewage treatment system to improve the problems of poor harmlessness effect and poor sanitary conditions of rural domestic sewage treatment.
[0004] A rural domestic sewage treatment system described in the present invention comprises a water storage module and a filtration module arranged in sequence from front to back; a water storage cavity is provided in the water storage module, a first water inlet communicating with the water storage cavity is provided at the front of the water storage module, a first water outlet communicating with the water storage cavity is provided at the rear of the water storage module, and the first water inlet is higher than the first water outlet; a filtration cavity is provided in the filtration module, a second water inlet communicating with the filtration cavity is provided at the front of the filtration module, a second water outlet communicating with the filtration cavity is provided at the rear of the filtration module, and the second water inlet is higher than the first water outlet at or level with the second water outlet, the second water inlet is connected to the first water outlet and has the same height; a filtration structure for sewage to pass through is provided in the filtration chamber, the filtration structure comprises a first perforated plate, a multi-stage filtration layer and a second perforated plate arranged in sequence from front to back, the multi-stage filtration layer comprises a quartz gravel layer, a first limestone gravel layer and a second limestone gravel layer arranged in sequence from front to back, the average particle size of the second limestone gravel layer is larger than the average particle size of the first limestone gravel layer, and the average particle size of the first limestone gravel layer is larger than the average particle size of the quartz gravel layer.
[0005] Furthermore, the multi-stage filtration layer further includes a third limestone gravel layer arranged behind the second limestone gravel layer, and the average particle size of the third limestone gravel layer is greater than the average particle size of the second limestone gravel layer.
[0006] Furthermore, the multi-stage filtration layer further includes a fourth limestone gravel layer arranged behind the third limestone gravel layer, and the average particle size of the fourth limestone gravel layer is greater than the average particle size of the third limestone gravel layer.
[0007] Furthermore, an aeration system is provided in the multi-stage infiltration layer.
[0008] Furthermore, the aeration system includes an aeration pipe extending in the front-to-back direction, and the aeration pipe is provided with a plurality of aeration holes in the axial and circumferential directions. The filtration module also includes a vertically arranged aeration connecting pipe, the rear end of the aeration pipe is connected to the aeration connecting pipe, and the upper end of the aeration connecting pipe passes through the cavity wall of the filtration chamber and extends outward.
[0009] Furthermore, a sludge trough for settling sludge is provided at the bottom of the water storage chamber, the front side wall of the sludge trough is connected to the front cavity wall of the water storage chamber, the rear side wall of the sludge trough gradually tilts backward from bottom to top, and the rear side wall of the sludge trough is connected to the rear cavity wall of the water storage chamber.
[0010] Furthermore, the water storage module also includes a sewage cleaning port communicating with the inside and outside of the water storage chamber and a sewage cleaning cover for opening / closing the sewage cleaning port.
[0011] Furthermore, a serrated plate is provided in the water storage chamber in front of the first water outlet and perpendicular to the direction of water flow, the teeth of the serrated plate are arranged horizontally, the tooth peaks of the serrated plate are arranged upward, and the tooth valleys of the serrated plate are higher than the lower edge of the first water outlet.
[0012] Furthermore, the water storage module also includes an exhaust hole communicating with the inside and outside of the water storage chamber and an exhaust cover for opening / closing the exhaust hole.
[0013] Furthermore, the bottom of the sludge tank is provided with a mud discharge hole communicating with the inside and outside of the water storage cavity, and the bottom of the sludge tank is also provided with a mud discharge hole cover for realizing opening / closing of the mud discharge hole.
[0014] The beneficial effects of the present invention lie in the fact that, through the infiltration structure composed of fine to coarse quartz gravel layers, a first limestone gravel layer, and a second limestone gravel layer, this structure prevents large impurities in domestic sewage from passing through the infiltration structure, thereby forming secondary precipitation and facilitating anaerobic fermentation of domestic sewage. Consequently, impurities, pathogens, and parasite eggs contained in domestic sewage are essentially eliminated after passing through the infiltration structure. Furthermore, the multi-stage infiltration layer utilizes gravel containing limestone. Experimental studies have shown that adding limestone gravel to the infiltration layer improves the removal rate of pollutant indicators. Although chemical precipitates produced by the reaction of limestone with total phosphorus adhere to the pores and can reduce the permeability of the matrix, the active materials in the limestone gravel dissolve with the sewage, forming dissolution grooves on the gravel surface. This, in turn, expands the void space of the overall structure, helping the system achieve a dynamic equilibrium between dissolution and clogging, and effectively reducing the negative effects of chemical precipitation. An aeration system is incorporated within the multi-stage infiltration layer. Experimental results show that if the aeration system is used in the infiltration structure, domestic sewage will undergo contact oxidation in the infiltration structure, and the multi-level infiltration layers arranged from fine to coarse particle size along the water flow direction can produce a superposition effect, and the intensity of the effect on nitrogen and phosphorus is higher than that of a single graded matrix; experiments show that this anti-rhythmic contact oxidation multi-level infiltration layer structure has a removal rate of COD, TN, NH3-N and TP of 15.1%-18.5%, 2.1%-5.5%, 28.3%-32.7% and 40.2%-45.2% respectively, especially for total phosphorus removal. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a schematic structural diagram of the rural domestic sewage treatment system according to the present invention;
[0016] Figure 2 for Figure 1 Schematic diagram of the structure of the middle A part;
[0017] Figure 3 for Figure 1 Schematic diagram of the structure of the middle part B;
[0018] Figure 4 This is a flow chart of resource utilization of the rural domestic sewage treatment system according to the present invention;
[0019] Figure 5 This is a flow chart of the direct discharge method of the rural domestic sewage treatment system according to the present invention;
[0020] In the figure, 1 is a water storage module, 2 is a filtration module, 3 is a water storage chamber, 4 is a first water inlet, 5 is a first water outlet, 6 is a filtration chamber, 7 is a second water inlet, 8 is a second water outlet, 9 is a first perforated plate, 10 is a second perforated plate, 11 is a quartz gravel layer, 12 is a first limestone gravel layer, 13 is a second limestone gravel layer, 16 is an aeration pipe, 17 is an aeration hole, 18 is an aeration connecting pipe, 19 is a sludge tank, 20 is a sewage cleaning port, 21 is a sewage cleaning cover, 22 is a serrated plate, 23 is an exhaust hole, 24 is an exhaust cover, and 25 is a sludge discharge hole. DETAILED DESCRIPTION
[0021] The present invention will be further described below with reference to the accompanying drawings.
[0022] like Figure 1 The rural domestic sewage treatment system shown in the figure includes a water storage module 1 and a filtration module 2 arranged in sequence from front to back; a water storage chamber 3 is provided in the water storage module 1, a first water inlet 4 communicating with the water storage chamber 3 is provided at the front of the water storage module 1, and a first water outlet 5 communicating with the water storage chamber 3 is provided at the rear of the water storage module 1, and the first water inlet 4 is higher than the first water outlet 5; a filtration chamber 6 is provided in the filtration module 2, a second water inlet 7 communicating with the filtration chamber 6 is provided at the front of the filtration module 2, and a second water outlet 8 communicating with the filtration chamber 6 is provided at the rear of the filtration module 2, and the second water inlet 7 is higher than or level with the second water outlet 8, and the second water inlet 7 is connected to the first water outlet 5 and has the same height; a filtration structure for sewage to pass through is provided in the filtration chamber 6, such as Figure 1 、 Figure 2 and Figure 3As shown, the filtration structure includes a first perforated plate 9, a multi-stage filtration layer and a second perforated plate 10 arranged in sequence from front to back. The multi-stage filtration layer includes a quartz gravel layer 11, a first limestone gravel layer 12 and a second limestone gravel layer 13 arranged in sequence from front to back. The average particle size of the second limestone gravel layer 13 is larger than the average particle size of the first limestone gravel layer 12, and the average particle size of the first limestone gravel layer 12 is larger than the average particle size of the quartz gravel layer 11. The first water inlet 4 is higher than the first water outlet 5, the second water inlet 7 is flush with the first water outlet 5, and the second water outlet 8 is lower than the second water inlet 7. The domestic sewage will flow through the first water inlet 4, the first water outlet 5, the second water inlet 7 and the second water outlet 8 in sequence. After the domestic sewage enters the water storage chamber 3 through the first water inlet 4, the feces in the domestic sewage are precipitated. The domestic sewage after the first treatment flows into the infiltration chamber 6 after passing through the first water outlet 5 and the second water inlet 7. The infiltration structure in the infiltration chamber 6 includes a quartz gravel layer 11 from fine to coarse, a first limestone gravel layer 12 and a second limestone gravel layer 13. This structure makes it difficult for large-volume impurities in the domestic sewage to pass through the infiltration structure. This will form secondary precipitation and is beneficial to the anaerobic fermentation of domestic sewage. Therefore, after the domestic sewage passes through the infiltration structure, the impurities, pathogens, and parasite eggs contained in it will be basically eliminated; at the same time, the multi-stage infiltration layer uses gravel containing limestone material. Experiments have shown that increasing the limestone gravel has a higher removal rate for pollution indicators. Although the chemical precipitate produced by the reaction of limestone and total phosphorus adheres to the inside of the pores and may cause the permeability of the matrix to decrease, the active materials of the limestone gravel dissolve with the sewage, and the gravel surface is dissolved, resulting in dissolution grooves, which to a certain extent expand the void space of the overall structure, help the system achieve a dynamic balance of dissolution and blockage, and effectively reduce the negative impact of chemical precipitation.
[0023] Preferably, the multi-stage infiltration layer further includes a third limestone gravel layer located after the second limestone gravel layer 13, wherein the average particle size of the third limestone gravel layer is greater than the average particle size of the second limestone gravel layer 13. Preferably, the multi-stage infiltration layer further includes a fourth limestone gravel layer located after the third limestone gravel layer, wherein the average particle size of the fourth limestone gravel layer is greater than the average particle size of the third limestone gravel layer. By providing multiple limestone gravel layers for reaction with domestic sewage, the pollution indicators in domestic sewage can be reduced to a greater extent. This embodiment takes as an example only the quartz gravel layer 11, the first limestone gravel layer 12, and the second limestone gravel layer 13.
[0024] Preferably, an aeration system is installed within the multi-stage percolation layer. Experimental results indicate that incorporating an aeration system into the percolation structure allows for contact oxidation of domestic sewage within the structure. The multi-stage percolation layer, arranged in a particle size distribution from fine to coarse along the flow direction, can produce a cumulative effect, resulting in a stronger nitrogen and phosphorus removal than a single graded matrix. Experiments have shown that this counter-rhythmic contact oxidation multi-stage percolation layer structure achieves removal rates of 15.1%-18.5% for COD, 2.1%-5.5% for TN, 28.3%-32.7% for NH3-N, and 40.2%-45.2% for TP, respectively, with particularly good results for total phosphorus removal.
[0025] Preferably, the aeration system includes an aeration pipe 16 whose length extends in the front-to-back direction, and a plurality of aeration holes 17 are provided in the axial and circumferential directions of the aeration pipe 16. The infiltration module 2 also includes a vertically arranged aeration connecting pipe 18. The rear end of the aeration pipe 16 is connected to the aeration connecting pipe 18, and the upper end of the aeration connecting pipe 18 passes through the cavity wall of the infiltration chamber 6 and extends outward. By providing the aeration pipe 16 whose length extends in the front-to-back direction, contact oxidation of domestic sewage occurs from front to back, and the degree of removal of nitrogen and phosphorus is better. The advantage of this arrangement is that even if contact oxidation is not used, when the infiltration structure is blocked, backwashing of the infiltration structure can be achieved by connecting tap water to the upper end of the aeration connecting pipe 18 to avoid blockage of the infiltration structure, achieving a two-pronged effect.
[0026] Preferably, a sludge trough 19 for settling sludge is provided at the bottom of the water storage chamber 3. The front side wall of the sludge trough 19 is connected to the front wall of the water storage chamber 3, and the rear side wall of the sludge trough 19 gradually slopes backward from bottom to top, and the rear side wall of the sludge trough 19 is connected to the rear wall of the water storage chamber 3. As the rear side wall of the sludge trough 19 gradually slopes backward from bottom to top, as driven by the water flow, more feces and impurities in the domestic sewage will be deposited on the rear side wall of the sludge trough 19, and the rear side wall of the sludge trough 19 forms a slope, so that the sludge moves downward on the slope and settles to the bottom of the sludge trough 19.
[0027] Preferably, the water storage module 1 further includes a cleaning port 20 communicating with the inside and outside of the water storage chamber 3 and a cleaning cover 21 for opening / closing the cleaning port 20. If there is too much sludge in the water storage chamber 3, the cleaning cover 21 can be opened and manually cleaned.
[0028] Preferably, a serrated plate 22 is provided in the water storage chamber 3 in front of the first water outlet 5 and perpendicular to the direction of water flow. The serrations of the serrated plate 22 are arranged horizontally, the crests of the serrated plate 22 are arranged upward, and the valleys of the serrated plate 22 are higher than the lower edge of the first water outlet 5. By providing the serrated plate 22, impurities floating on the surface of the domestic sewage will be blocked by the serrated portion of the serrated plate 22, preventing them from clogging subsequent portions.
[0029] Preferably, the water storage module 1 further includes an exhaust hole 23 communicating with the inside and outside of the water storage chamber 3 and an exhaust cover 24 for opening / closing the exhaust hole 23. The advantage of the exhaust hole 23 is that it facilitates the discharge of gas formed after anaerobic fermentation of domestic sewage.
[0030] Preferably, the bottom of the sludge tank 19 is provided with a mud discharge hole 25 communicating with the inside and outside of the water storage chamber 3, and the bottom of the sludge tank 19 is also provided with a mud discharge hole cover for opening / closing the mud discharge hole 25. The mud discharge hole 25 can also be used to discharge the sludge.
[0031] Preferably, according to actual conditions, the filtration module 2 may also be provided with corresponding sewage cleaning ports, sewage cleaning covers, vents, vent covers, mud discharge holes and mud discharge hole covers with reference to the water storage module 1 .
[0032] The implementation method of this embodiment is that domestic sewage enters the water storage chamber 3 through the first water inlet 4, and undergoes the first adjustment, sedimentation and anaerobic fermentation. Part of the sludge containing feces, fecal residue and fecal skin is precipitated, and the serrated plate 22 blocks the impurities floating on the surface of the domestic sewage. The treated domestic sewage enters the infiltration chamber 6 through the first water outlet 5 and the second water inlet 7. At this time, the domestic sewage undergoes secondary anaerobic fermentation. Since the quartz gravel layer 11, the first limestone gravel layer 12, and the second limestone gravel layer 13 of the infiltration structure are arranged to have a structure with a diameter that increases from small to large from front to back, impurities in the domestic sewage are not easy to pass through the infiltration structure to produce secondary precipitation. At the same time, the multi-stage infiltration layer uses gravel containing limestone material. Experiments show that adding limestone gravel has a higher removal rate for pollution indicators. Although the chemical precipitate produced by the reaction of limestone with total phosphorus adheres to the pores While the internal permeability of the matrix may be reduced, the active materials in the limestone gravel and the sewage dissolve, forming dissolution grooves on the gravel surface. This, in turn, expands the void space within the overall structure, helping the system achieve a dynamic equilibrium between dissolution and clogging, effectively reducing the negative impact of chemical precipitation. By installing an aeration system within the percolation structure, the domestic sewage undergoes contact oxidation. The multi-stage percolation layer, arranged in a particle size distribution from fine to coarse along the flow direction, produces a cumulative effect, with a higher nitrogen and phosphorus removal intensity than a single-graded matrix. Experiments have shown that this counter-rhythmic contact oxidation multi-stage percolation layer structure achieves removal rates of 15.1%-18.5% for COD, 2.1%-5.5%, 28.3%-32.7%, and 40.2%-45.2% for TN, respectively, with particularly good removal of total phosphorus. The aeration tubes 16 can also be used to backwash the multi-stage percolation layer, achieving a dual purpose of aeration and backwashing. The domestic sewage treated by this rural domestic sewage treatment system is cleaner, the harmlessness effect is greatly improved, the treatment efficiency is higher, and it is cleaner and more hygienic.
[0033] The water storage module 1 and the infiltration module 2 of the rural domestic sewage treatment system can be individually designed in shape according to actual conditions. The water storage module 1 and the infiltration module 2 of the present embodiment are both square in shape. The length and width of the water storage module 1 of the present embodiment are both 1 meter, and the depth is 0.8-1 meter. The first water outlet 5 is 0.05-0.1 meter lower than the first water inlet 4. The angle between the rear side wall of the sludge tank 19 and the horizontal plane is 15-30 degrees; the distance between the serrated plate 22 and the first water outlet 5 is 0.1-0.2 meters. A first top baffle is provided on the upper part of the water storage module 1. The top baffle is enclosed to form a space that can be filled with soil, and farmers can plant flowers, vegetables and other crops on it; the length of the infiltration module 2 is 1-1.1 meters , 1 meter in width and 0.8-1 meter in depth, the second water outlet 8 is 0-0.05 meter lower than the second water inlet 7, and a percolation structure is set at 0.5 meter of the second water inlet 7. The overall thickness of the percolation structure is 0.4-0.5 meter, and the apertures of the first perforated plate 9 and the second perforated plate 10 are based on the standard that quartz gravel or limestone gravel is not easy to leak out; in this example, the thickness of the quartz gravel is 0.1-0.15 meter, and the particle size range is 0.005-0.015 meter. The thickness of the first limestone gravel layer 12 is 0.15-0.2 meter, and the particle size is 0.01-0.02 meter. The thickness of the second limestone gravel layer 13 is 0.15-0.2 meter, and the particle size is 0.015-0.03 meter.
[0034] In addition to this embodiment, the water storage module 1 and the filtration module 2 can also be combined differently with this embodiment to meet different requirements; according to different utilization methods of domestic sewage, this embodiment specifically provides two utilization methods.
[0035] One of the ways is resource utilization, such as Figure 4 As shown, by separately arranging a water storage module after the water storage module 1 and the infiltration module 2 explained in this embodiment, domestic grey water can directly enter the water storage module without passing through the infiltration module, and domestic black water enters the water storage module 1 and the infiltration module 2 of this embodiment respectively; through this arrangement, domestic black water and grey water are treated separately, so that the treatment effect of domestic sewage is better and the treatment efficiency is faster; the treated domestic sewage can meet the farmland irrigation standard, and the treated domestic sewage is pumped into the high-level water collection tank through a submersible pump to implement irrigation of farmland, gardens, woodlands, grasslands, small vegetable gardens or orchards; this combination of the water storage module 1, the infiltration module 2 and the water storage module can be arranged in a straight line or in an "L" shape according to different installation spaces.
[0036] Another way is direct discharge, such as Figure 5As shown, in order to meet the standard for direct discharge, domestic sewage should be treated more deeply. Therefore, a filtration module and a water storage module are added in sequence after the water storage module 1 and the filtration module 2 of this embodiment. Similarly, domestic black water enters the water storage module 1 and the filtration module 2 of this embodiment in sequence, and then enters the newly added filtration module and the water storage module in sequence. The domestic black water is treated more deeply, so that the discharged water quality meets the direct discharge standard; in addition, gray water can directly enter the newly added water storage module, or an additional filtration module can be added to separately treat the domestic gray water, and then the treated domestic gray water is discharged into the water storage module at the end; in short, this rural domestic sewage treatment system can be implemented separately or split and combined according to actual needs.
[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.
Claims
1. A rural domestic sewage treatment system, characterized in that: The invention comprises a water storage module (1) and a filtration module (2) which are arranged in sequence from front to back; the water storage module (1) is provided with a water storage chamber (3), the front part of the water storage module (1) is provided with a first water inlet (4) which is connected to the water storage chamber (3), the rear part of the water storage module (1) is provided with a first water outlet (5) which is connected to the water storage chamber (3), and the first water inlet (4) is higher than the first water outlet (5); the filtration module (2) is provided with a filtration chamber (6), the front part of the filtration module (2) is provided with a second water inlet (7) which is connected to the filtration chamber (6), the rear part of the filtration module (2) is provided with a second water outlet (8) which is connected to the filtration chamber (6), the second water inlet (7) is higher than or level with the second water outlet (8), and the second water inlet (7) is connected to the first water outlet (5) and has the same height; the filtration chamber (6) is provided with a filtration structure for sewage to pass through, and the filtration structure comprises: a first perforated plate (9), a multi-stage perforation layer and a second perforated plate (10) arranged in sequence from front to back, the multi-stage perforation layer comprising a quartz gravel layer (11), a first limestone gravel layer (12) and a second limestone gravel layer (13), the average particle size of the second limestone gravel layer (13) being larger than the average particle size of the first limestone gravel layer (12), and the average particle size of the first limestone gravel layer (12) being larger than the average particle size of the quartz gravel layer (11); an aeration system is arranged in the multi-stage perforation layer, the aeration system comprising an aeration pipe (16) extending in a front-to-rear direction, the aeration pipe (16) being provided with a plurality of aeration holes (17) in an axial direction and a circumferential direction; the perforation module (2) further comprising an aeration connecting pipe (18) arranged vertically, the rear end of the aeration pipe (16) being connected to the aeration connecting pipe (18), the upper end of the aeration connecting pipe (18) penetrating the cavity wall of the percolation cavity (6) and extending outward; A sawtooth plate (22) is provided in the water storage chamber (3) in front of the first water outlet (5) and perpendicular to the water flow direction, the saw teeth of the sawtooth plate (22) are arranged horizontally, the tooth peaks of the sawtooth plate (22) are arranged upwards, and the tooth valleys of the sawtooth plate (22) are higher than the lower edge of the first water outlet (5).
2. The rural domestic sewage treatment system according to claim 1, characterized in that: The multi-stage percolation layer further comprises a third limestone gravel layer arranged behind the second limestone gravel layer (13), the average particle size of the third limestone gravel layer being greater than the average particle size of the second limestone gravel layer (13).
3. The rural domestic sewage treatment system according to claim 2, characterized in that: The multi-stage infiltration layer further includes a fourth limestone gravel layer arranged behind the third limestone gravel layer, and the average particle size of the fourth limestone gravel layer is greater than the average particle size of the third limestone gravel layer.
4. According to the rural domestic sewage treatment system described in claims 1-3, a sludge trough (19) for settling sludge is provided at the bottom of the water storage chamber (3), the front side wall of the sludge trough (19) is connected to the front cavity wall of the water storage chamber (3), the rear side wall of the sludge trough (19) is gradually inclined backward from bottom to top, and the rear side wall of the sludge trough (19) is connected to the rear cavity wall of the water storage chamber (3).
5. The rural domestic sewage treatment system according to claim 1, characterized in that: The water storage module (1) further comprises a cleaning port (20) communicating with the inside and outside of the water storage chamber (3), and a cleaning cover (21) for opening / closing the cleaning port (20).
6. The rural domestic sewage treatment system according to claim 1, characterized in that: The water storage module (1) further comprises an exhaust hole (23) communicating with the inside and outside of the water storage chamber (3), and an exhaust cover (24) for realizing opening / closing of the exhaust hole (23).
7. The rural domestic sewage treatment system according to claim 4, characterized in that: The bottom of the sludge trough (19) is provided with a sludge discharge hole (25) communicating with the inside and outside of the water storage chamber (3), and the bottom of the sludge trough (19) is also provided with a sludge discharge hole cover for realizing opening / closing of the sludge discharge hole (25).