A reverse rhythmic treatment system for rural domestic sewage

Abstract

The invention relates to a reverse rhythmic treatment system for rural domestic sewage, comprising a water storage module, a reverse osmosis filtration module and a forward osmosis filtration module; the water storage module is provided with a water storage cavity, a first water inlet and a first water outlet with a height lower than the first water inlet; the reverse osmosis filtration module is provided with a reverse osmosis filtration cavity, a second water inlet connected to the first water outlet and having the same height, and a second water outlet with a height lower than or level with the second water inlet; the forward osmosis filtration module is provided with a forward osmosis filtration cavity, a third water inlet connected to the second water outlet and having the same height, and a third water outlet with a height lower than or level with the third water inlet; the reverse osmosis filtration cavity is provided with a reverse osmosis filtration structure, the reverse osmosis filtration structure comprises a multi-stage reverse osmosis filtration layer; the forward osmosis filtration cavity is provided with a forward osmosis filtration structure, the forward osmosis filtration structure comprises a multi-stage forward osmosis filtration layer; the multi-stage reverse osmosis filtration layer is provided with a first aeration system, and the multi-stage forward osmosis filtration layer is provided with a second aeration system. The invention effectively improves the problem of high total phosphorus in the existing rural domestic sewage after treatment.

Description

Technical Field

[0001] The invention relates to the field of domestic sewage treatment, and in particular to a rural domestic sewage reverse rhythm treatment system. Background Art

[0002] Rural domestic sewage has the characteristics of scattered collection and concentrated discharge periods. After the dry toilets are converted to water toilets, the existing three-chamber septic tanks are often fully loaded or overloaded, resulting in poor harmless treatment effects and increased sewage discharge, which often cause greater pollution and even form black and smelly water bodies. The main principle of the existing three-chamber septic tank is to remove fecal skin or fecal residue in domestic sewage through anaerobic fermentation. A large number of parasite eggs or bacteria are hidden in fecal skin or fecal residue. Most of the harmful substances in domestic sewage treated by the three-chamber septic tank are eliminated, but the problem of high total phosphorus in sewage cannot be well solved. Therefore, domestic sewage treated by the three-chamber septic tank cannot be discharged directly, because excessive total phosphorus will cause eutrophication of the water body, thereby affecting the water quality of the water body. Summary of the invention

[0003] The purpose of the present invention is to provide a reverse rhythmic treatment system for rural domestic sewage to improve the problem of high total phosphorus content in existing rural domestic sewage after treatment.

[0004] The rural domestic sewage reverse rhythm treatment system described in the present invention is characterized in that it includes a water storage module, a reverse osmosis filtration module and a forward osmosis filtration module arranged in sequence from front to back; a water storage cavity is provided in the water storage module, a first water inlet connected to the water storage cavity is provided at the front of the water storage module, a first water outlet connected to 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 reverse osmosis filtration cavity is provided in the reverse osmosis filtration module, a second water inlet connected to the reverse osmosis filtration cavity is provided at the front of the reverse osmosis filtration module, and the reverse osmosis filtration cavity is provided. The reverse osmosis filtration module is provided with a second water outlet connected to the reverse osmosis filtration chamber at the rear, the second water inlet is higher than or level with the second water outlet, the second water inlet is connected to the first water outlet and has the same height; the forward osmosis filtration module is provided with a forward osmosis filtration chamber, the front of the forward osmosis filtration module is provided with a third water inlet connected to the forward osmosis filtration chamber, the rear of the forward osmosis filtration module is provided with a third water outlet connected to the forward osmosis filtration chamber, the third water inlet is higher than or level with the third water outlet, the third water inlet is connected to the second water outlet and The reverse osmosis filtration chamber has the same height; a reverse osmosis filtration structure is arranged in the reverse osmosis filtration chamber, and the reverse osmosis filtration structure includes a first perforated plate, a multi-stage reverse osmosis filtration layer and a second perforated plate arranged in sequence from front to back; the multi-stage reverse osmosis filtration layer includes a first 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; the forward osmosis filtration chamber has a forward osmosis filtration structure, The positive infiltration structure includes a third perforated plate, a multi-stage positive infiltration layer and a fourth perforated plate which are arranged in sequence from front to back; the multi-stage positive infiltration layer includes a fourth limestone gravel layer, a third limestone gravel layer and a second quartz gravel layer which are arranged in sequence from front to back; the average particle size of the fourth limestone gravel layer is greater than the average particle size of the third limestone gravel layer; the average particle size of the third limestone gravel layer is greater than the average particle size of the second quartz gravel layer; a first aeration system is provided in the multi-stage reverse osmosis layer, and a second aeration system is provided in the multi-stage positive infiltration layer.

[0005] Furthermore, the multi-stage reverse osmosis filtration layer also includes a fifth limestone gravel layer arranged behind the second limestone gravel layer, and the average particle size of the fifth limestone gravel layer is greater than the average particle size of the second limestone gravel layer.

[0006] Furthermore, the multi-stage reverse osmosis filtration layer also includes a sixth limestone gravel layer arranged after the fifth limestone gravel layer, and the average particle size of the sixth limestone gravel layer is greater than the average particle size of the fifth limestone gravel layer.

[0007] Furthermore, the multi-stage positive infiltration layer also includes a seventh limestone gravel layer disposed before the fourth limestone gravel layer, and the average particle size of the seventh limestone gravel layer is greater than the average particle size of the fourth limestone gravel layer.

[0008] Furthermore, the multi-stage positive infiltration layer also includes an eighth limestone gravel layer disposed before the seventh limestone gravel layer, and the average particle size of the eighth limestone gravel layer is greater than the average particle size of the seventh limestone gravel layer.

[0009] Furthermore, the first aeration system includes a first aeration pipe whose length extends in the front-to-back direction, and a plurality of first aeration holes are arranged in the axial and circumferential directions of the first aeration pipe. The reverse osmosis module also includes a first aeration connecting pipe arranged vertically, and the rear end of the first aeration pipe is connected to the first aeration connecting pipe, and the upper end of the first aeration connecting pipe penetrates the cavity wall of the reverse osmosis cavity upward and extends outward.

[0010] Furthermore, the second aeration system includes a second aeration tube whose length extends in the front-to-back direction, and a plurality of second aeration holes are arranged in the axial and circumferential directions of the second aeration tube. The forward filtration module also includes a second aeration connecting tube arranged vertically, and the rear end of the second aeration tube is connected to the second aeration connecting tube, and the upper end of the second aeration connecting tube penetrates the cavity wall of the forward filtration cavity upward and extends outward.

[0011] 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.

[0012] Furthermore, the water storage module also includes a cleaning port communicating with the inside and outside of the water storage cavity and a cleaning cover for opening / closing the cleaning port.

[0013] Furthermore, a serrated plate is provided in the water storage chamber in front of the first water outlet and perpendicular to the sewage flow direction, 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.

[0014] The beneficial effect of the present invention is that by setting a water storage module, domestic sewage enters the water storage cavity for the first anaerobic fermentation, regulation and precipitation. After the domestic sewage treated by the first process enters the reverse osmosis filtration module, the secondary anaerobic fermentation of the domestic sewage is better because the particle size of the multi-stage reverse osmosis filtration layer in the reverse osmosis filtration module changes from fine to coarse from the quartz gravel layer to the second limestone gravel layer. Moreover, this multi-stage reverse osmosis filtration layer structure from fine to coarse makes it difficult for large-volume impurities to pass through the reverse osmosis filtration structure, and the domestic sewage purified by the reverse osmosis filtration structure is cleaner. At the same time, the reverse osmosis filtration structure uses limestone gravel. Experiments show that increasing the removal rate of pollution indicators is higher with the addition of limestone gravel. 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 material of the limestone gravel dissolves with the sewage, and the gravel surface is dissolved to produce dissolution grooves, which to a certain extent expands the void space of the overall structure, which helps the system to achieve a dynamic balance of dissolution-blocking and effectively reduces the negative impact of chemical precipitation. A reverse osmosis filtration module structure is set after the reverse osmosis filtration module. The first aeration system is arranged in the reverse osmosis module and the second aeration system is arranged in the forward osmosis module, so that the domestic sewage passing through the multi-stage reverse osmosis layer and the multi-stage forward osmosis layer undergoes contact oxidation. The experimental results show that if the first aeration system is used in the multi-stage reverse osmosis layer, the multi-stage reverse osmosis layer structure with particle size arranged from fine to coarse 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; in addition, the particle size structure of the multi-stage forward osmosis layer is from coarse to fine, forming a positive rhythm of the forward osmosis module. The rhythm layer is used in combination with the anti-rhythmic layer of the reverse osmosis module to form a reverse-positive rhythmic filtration structure, but the positive rhythmic filtration layer cannot be used alone; experiments show that when the first aeration system and the second aeration system are turned on, the comprehensive removal rates of COD, TN, NH3-N and TP in the reverse-positive rhythmic filtration structure are 20.1%-25.3%, 2.5%-5.8%, 35.6%-43.8 and 45.7%-55.2%, respectively. Therefore, it can be seen that this reverse-positive rhythmic filtration structure is particularly effective in removing total phosphorus. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the reverse rhythmic treatment system for rural domestic sewage according to the present invention;

[0016] Figure 2 for Figure 1 The structural diagram of the middle A part;

[0017] Figure 3 for Figure 1 The structural diagram of the middle B part;

[0018] Figure 4 for Figure 1 The structural diagram of the middle C part;

[0019] Figure 5 for Figure 1 Schematic diagram of the structure of the middle D part.

[0020] In the figure, 1 is a water storage module, 2 is a reverse osmosis filtration module, 3 is a forward osmosis filtration module, 4 is a water storage chamber, 5 is a first water inlet, 6 is a first water outlet, 7 is a reverse osmosis filtration chamber, 8 is a second water inlet, 9 is a second water outlet, 10 is a forward osmosis filtration chamber, 11 is a third water inlet, 12 is a third water outlet, 13 is a first perforated plate, 14 is a second perforated plate, 15 is a first quartz gravel layer, 16 is a first limestone gravel layer, 17 is a second limestone gravel layer, 18 is a third Perforated plate, 19—fourth perforated plate, 20—second quartz gravel layer, 21—third limestone gravel layer, 22—fourth limestone gravel layer, 27—first aeration tube, 28—first aeration hole, 29—first aeration connecting tube, 30—second aeration tube, 31—second aeration hole, 32—second aeration connecting tube, 33—sludge trough, 34—sludge cleaning port, 35—sludge cleaning cover, 36—serrated plate, 37—exhaust hole, 38—exhaust cover, 39—sludge discharge hole. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] like Figure 1-Figure 5The rural domestic sewage reverse rhythm treatment system shown in the figure comprises a water storage module 1, a reverse osmosis filtration module 2 and a forward osmosis filtration module 3 which are arranged in sequence from front to back; a water storage chamber 4 is arranged in the water storage module 1, a first water inlet 5 which is connected to the water storage chamber 4 is arranged at the front of the water storage module 1, a first water outlet 6 which is connected to the water storage chamber 4 is arranged at the rear of the water storage module 1, and the first water inlet 5 is higher than the first water outlet 6; a reverse osmosis filtration chamber 7 is arranged in the reverse osmosis filtration module 2, a second water inlet 8 which is connected to the reverse osmosis filtration chamber 7 is arranged at the front of the reverse osmosis filtration module 2, and a second water inlet 8 which is connected to the reverse osmosis filtration chamber 7 is arranged at the rear of the reverse osmosis filtration module 2. A second water outlet 9 connected to the reverse osmosis filter chamber 7 is provided, and a second water inlet 8 is higher than or level with the second water outlet 9, and the second water inlet 8 is connected to the first water outlet 6 and has the same height; a forward osmosis filter chamber 10 is provided in the forward osmosis filter module 3, and a third water inlet 11 connected to the forward osmosis filter chamber 10 is provided at the front of the forward osmosis filter module 3, and a third water outlet 12 connected to the forward osmosis filter chamber 10 is provided at the rear of the forward osmosis filter module 3, and the third water inlet 11 is higher than or level with the third water outlet 12, and the third water inlet 11 is connected to the second water outlet 9 and has the same height; the reverse osmosis filter chamber 7 A reverse osmosis structure is arranged inside, and the reverse osmosis structure includes a first perforated plate 13, a multi-stage reverse osmosis layer and a second perforated plate 14 arranged in sequence from front to back. The multi-stage reverse osmosis layer includes a first quartz gravel layer 15, a first limestone gravel layer 16 and a second limestone gravel layer 17 arranged in sequence from front to back. The average particle size of the second limestone gravel layer 17 is larger than the average particle size of the first limestone gravel layer 16, and the average particle size of the first limestone gravel layer 16 is larger than the average particle size of the first quartz gravel layer 15. A forward osmosis structure is arranged inside the forward osmosis chamber 10, and the forward osmosis structure The structure includes a third perforated plate 18, a multi-stage forward infiltration layer and a fourth perforated plate 19 which are arranged in sequence from front to back. The multi-stage forward infiltration layer includes a fourth limestone gravel layer 22, a third limestone gravel layer 21 and a second quartz gravel layer 20 which are arranged in sequence from front to back. The average particle size of the fourth limestone gravel layer 22 is greater than the average particle size of the third limestone gravel layer 21, and the average particle size of the third limestone gravel layer 21 is greater than the average particle size of the second quartz gravel layer 20. The multi-stage reverse osmosis layer is provided with a first aeration system, and the multi-stage forward infiltration layer is provided with a second aeration system.By setting up the water storage module 1, the domestic sewage enters the water storage chamber 4 for the first anaerobic fermentation, regulation and precipitation. After the domestic sewage after the first treatment enters the reverse osmosis module 2, the secondary anaerobic fermentation of the domestic sewage is better because the particle size of the multi-stage reverse osmosis layer in the reverse osmosis module 2 changes from fine to coarse from the quartz gravel layer to the second limestone gravel layer 17. In addition, this multi-stage reverse osmosis layer structure from fine to coarse makes it difficult for large-volume impurities to pass through the reverse osmosis structure, and the domestic sewage purified by the reverse osmosis structure is cleaner. At the same time, the reverse osmosis structure uses limestone gravel. Experiments show that increasing the limestone gravel has a significant effect on the removal of pollution indicators. The removal rate is higher. Although the chemical precipitation 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 and the sewage dissolve, and the gravel surface is dissolved to produce dissolution grooves, which to a certain extent expand the void space of the overall structure, help the system to achieve a dynamic balance of dissolution-clogging, and effectively reduce the negative impact of chemical precipitation; a forward osmosis module 3 with a structure basically opposite to that of the reverse osmosis module 2 is set after the reverse osmosis module 2, and a first aeration system is set in the reverse osmosis module 2, and a second aeration system is set in the forward osmosis module 3, so that after multiple reverse osmosis layers and multiple The domestic sewage in the first-stage forward infiltration layer undergoes contact oxidation. The experimental results show that if the first aeration system is used in the multi-stage reverse osmosis layer, the multi-stage reverse osmosis layer structure with particle sizes arranged from fine to coarse 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; in addition, the particle size structure of the multi-stage forward infiltration layer is from coarse to fine, forming a positive rhythm layer of the forward infiltration module 3, which is used in combination with the reverse rhythm layer of the reverse osmosis module 2 to form a reverse-positive rhythm infiltration structure, but the positive rhythm infiltration layer cannot be used alone; the experiment shows that when the first aeration system and the second aeration system are turned on, the reverse-positive rhythm infiltration structure has a great influence on COD and TN. The comprehensive removal rates of NH3-N and TP were 20.1%-25.3%, 2.5%-5.8%, 35.6%-43.8% and 45.7%-55.2% respectively. Therefore, it can be seen that the reverse-positive rhythmic filtration structure has a particularly obvious effect on the removal of total phosphorus; at the same time, the structure of this embodiment shows that the scientific configuration of fillers with different lithologies and different particle sizes can effectively improve the sewage treatment capacity; under the condition of DO concentration of 2.29-3.30 mg / L, the model was domesticated with microorganisms for 31 days to form a stably operating microorganism-water-rock system, which can further improve the decontamination efficiency of the model.

[0023] Preferably, the multi-stage reverse osmosis filtration layer further includes a fifth limestone gravel layer arranged after the second limestone gravel layer 17, and the average particle size of the fifth limestone gravel layer is greater than the average particle size of the second limestone gravel layer 17. Preferably, the multi-stage reverse osmosis filtration layer further includes a sixth limestone gravel layer arranged after the fifth limestone gravel layer, and the average particle size of the sixth limestone gravel layer is greater than the average particle size of the fifth limestone gravel layer. Preferably, the multi-stage positive osmosis filtration layer further includes a seventh limestone gravel layer arranged in front of the fourth limestone gravel layer 22, and the average particle size of the seventh limestone gravel layer is greater than the average particle size of the fourth limestone gravel layer 22. Preferably, the multi-stage positive osmosis filtration layer further includes an eighth limestone gravel layer arranged in front of the seventh limestone gravel layer, and the average particle size of the eighth limestone gravel layer is greater than the average particle size of the seventh limestone gravel layer. The fifth limestone gravel layer, the sixth limestone gravel layer, the seventh limestone gravel layer and the eighth limestone gravel layer serve to increase the number of filtration layers of the multi-stage reverse filtration layer and the multi-stage forward filtration layer to achieve a better decontamination effect. However, this embodiment only takes the first quartz gravel layer 15, the first limestone gravel layer 16, the second limestone gravel layer 17, the second quartz gravel layer 20, the third limestone gravel layer 21 and the fourth limestone gravel layer 22 as an example.

[0024] As a preferred example, Figure 2 As shown, the first aeration system includes a first aeration tube 27 whose length extends in the front-to-back direction, and the first aeration tube 27 is provided with a plurality of first aeration holes 28 in the axial and circumferential directions. The reverse osmosis module 2 also includes a first aeration connecting tube 29 arranged vertically, and the rear end of the first aeration tube 27 is connected to the first aeration connecting tube 29, and the upper end of the first aeration connecting tube 29 penetrates the cavity wall of the reverse osmosis cavity 7 upward and extends outward. By providing the first aeration tube 27 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 reverse osmosis structure is blocked, by connecting tap water to the upper end of the first aeration connecting tube 29, the reverse osmosis structure can be backwashed to avoid the blockage of the reverse osmosis structure, achieving the effect of killing two birds with one stone.

[0025] As a preferred example, Figure 5As shown, the second aeration system includes a second aeration tube 30 whose length extends in the front-to-back direction, and the second aeration tube 30 is provided with a plurality of second aeration holes 31 in the axial and circumferential directions. The forward filtration module 3 also includes a second aeration connecting tube 32 arranged vertically, and the rear end of the second aeration tube 30 is connected to the second aeration connecting tube 32, and the upper end of the second aeration connecting tube 32 passes through the cavity wall of the forward filtration cavity 10 upward and extends outward. By providing the second aeration tube 30 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 forward filtration structure is blocked, by connecting tap water to the upper end of the second aeration connecting tube 32, backwashing of the forward filtration structure can be achieved to avoid blockage of the forward filtration structure, achieving the effect of killing two birds with one stone.

[0026] Preferably, a sludge tank 33 for settling sludge is provided at the bottom of the water storage chamber 4, the front side wall of the sludge tank 33 is connected to the front wall of the water storage chamber 4, the rear side wall of the sludge tank 33 is gradually tilted backward from bottom to top, and the rear side wall of the sludge tank 33 is connected to the rear wall of the water storage chamber 4. As the rear side wall of the sludge tank 33 is gradually tilted backward from bottom to top, with the driving effect of the water flow, more feces and impurities in the domestic sewage will be deposited on the rear side wall of the sludge tank 33, and the rear side wall of the sludge tank 33 forms a slope, so that the sludge moves downward on the slope and settles to the bottom of the sludge tank 33.

[0027] Preferably, the water storage module 1 further comprises a cleaning port 34 communicating with the inside and outside of the water storage chamber 4 and a cleaning cover 35 for opening / closing the cleaning port 34. If there is too much sludge in the water storage chamber 4, the cleaning cover 35 can be opened and then cleaned manually.

[0028] Preferably, a sawtooth plate 36 is provided in the water storage chamber 4 in front of the first water outlet 6 and perpendicular to the sewage flow direction, the sawtooth plate 36 has the saw teeth arranged horizontally, the tooth peaks of the sawtooth plate 36 are arranged upward, and the tooth valleys of the sawtooth plate 36 are higher than the lower edge of the first water outlet 6. By setting the sawtooth plate 36, the impurities floating on the surface of the domestic sewage will be blocked by the sawtooth part of the sawtooth plate 36 to prevent them from blocking the subsequent parts. Preferably, the water storage module 1 also includes an exhaust hole 37 connecting the inside and outside of the water storage chamber 4 and an exhaust cover 38 for opening / closing the exhaust hole 37. The advantage of setting the exhaust hole 37 is that it facilitates the discharge of the gas formed by the domestic sewage after anaerobic fermentation. Preferably, the bottom of the sludge tank 33 is provided with a mud discharge hole 39 connecting the inside and outside of the water storage chamber 4, and the bottom of the sludge tank 33 is also provided with a mud discharge hole cover for opening / closing the mud discharge hole 39. The discharge of sludge can also be achieved by setting the mud discharge hole 39. Preferably, according to actual conditions, the reverse osmosis module 2 and the forward osmosis module 3 may also be provided with corresponding sewage cleaning ports, sewage cleaning covers, exhaust holes, exhaust covers, mud discharge holes and mud discharge hole covers with reference to the water storage module 1.

[0029] The water storage module 1, reverse osmosis module 2 and forward osmosis module 3 of the reverse rhythmic treatment system for rural domestic sewage can be individually designed in shape according to actual conditions. The water storage module 1, reverse osmosis module 2 and forward osmosis module 3 of the present embodiment are all 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 6 is 0.05-0.1 meter lower than the first water inlet 5, and the angle between the rear side wall of the sludge tank 33 and the horizontal plane is 15-30 degrees; the distance between the serrated plate 36 and the first water outlet 6 is 0.1-0.2 meter. A top baffle is provided on the upper part of the water storage module 1, and 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 reverse osmosis module 2 is 1-1.1 meters , 1 meter wide and 0.8-1 meter deep. The second water outlet 9 is 0-0.05 meter lower than the second water inlet 8. A reverse osmosis filtration structure is arranged at 0.5 meter of the second water inlet 8. The overall thickness of the reverse osmosis filtration structure is 0.4-0.5 meter. The apertures of the first perforated plate 13 and the second perforated plate 14 are based on the standard that quartz gravel or limestone gravel is not easy to leak out; the size of the forward filtration module 3 refers to the reverse osmosis filtration module; 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 16 is 0.15-0.2 meter, and the particle size is 0.01-0.02 meter. The thickness of the second limestone gravel layer 17 is 0.15-0.2 meter, and the particle size is 0.015-0.03 meter.

[0030] The implementation method of this embodiment is that the domestic sewage enters the water storage chamber 4 through the first water inlet 5, undergoes the first adjustment, sedimentation and anaerobic fermentation, and part of the sludge containing feces, feces residue and feces skin is precipitated. The serrated plate 36 blocks the impurities floating on the surface of the domestic sewage, and the treated domestic sewage enters the reverse osmosis chamber 7 through the first water outlet 6 and the second water inlet 8. At this time, the domestic sewage undergoes secondary anaerobic fermentation. Since the first quartz gravel layer 15, the first limestone gravel layer 16, and the second limestone gravel layer 17 of the reverse osmosis structure are arranged in a structure where the diameters gradually increase from small to large from front to back, the impurities in the domestic sewage are not It is easy to pass through the reverse osmosis structure to produce secondary precipitation. At the same time, gravel containing limestone material is selected for the multi-stage reverse osmosis layer. Experiments show that adding limestone gravel has a higher removal rate for pollution indicators. Although the chemical precipitation produced by the reaction of limestone and total phosphorus adheres to the inside of the pores and can 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 to produce dissolution grooves, which to a certain extent expand the void space of the overall structure, help the system achieve a dynamic balance of dissolution-blocking, and effectively reduce the negative impact of chemical precipitation; by setting an aeration system in the reverse osmosis structure, the living The sewage is contact-oxidized, and the multi-stage reverse osmosis filtration layer arranged from fine to coarse in 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; by arranging a forward osmosis module 3 after the reverse osmosis module 2, the multi-stage forward osmosis filtration layer of the forward osmosis module 3 and the multi-stage reverse osmosis filtration layer of the reverse osmosis module 2 are arranged oppositely, and the first aeration system and the second aeration system are respectively added to the multi-stage reverse osmosis filtration layer and the multi-stage forward osmosis filtration layer, the particle size structure of the multi-stage forward osmosis layer is from coarse to fine, forming a positive rhythm layer of the forward osmosis module 3, and used in combination with the reverse rhythm layer of the reverse osmosis module 2 to form a reverse-positive rhythm filtration structure The experiment shows that when the first aeration system and the second aeration system are turned on, the comprehensive removal rates of COD, TN, NH3-N and TP by the reverse-positive rhythmic filtration structure are 20.1%-25.3%, 2.5%-5.8%, 35.6%-43.8% and 45.7%-55.2% respectively. Therefore, it can be seen that the reverse-positive rhythmic filtration structure has a particularly obvious effect on the removal of total phosphorus; the first aeration pipe 27 can also be used to backwash the multi-stage reverse osmosis layer, and the second aeration pipe 30 can also be used to backwash the multi-stage positive osmosis layer. Aeration and backwashing can achieve the effect of killing two birds with one stone. The domestic sewage treated by this rural domestic sewage reverse rhythmic treatment system is cleaner, especially the treatment effect on total phosphorus is better.

[0031] The rural domestic sewage reverse rhythm treatment system can also disassemble and combine the water storage module, reverse osmosis module and forward osmosis module to form a combination of a first water storage module, a first reverse osmosis module, a second reverse osmosis module, a forward osmosis module and a second water storage module. This combination, combined with the use of an aeration system, can easily form an AO process, i.e., an anaerobic aerobic process, to improve the effluent quality.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. 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 solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A rural domestic sewage reverse rhythm treatment system, characterized in that: The invention comprises a water storage module (1), a reverse osmosis filtration module (2) and a forward osmosis filtration module (3) which are arranged in sequence from front to back; the water storage module (1) is provided with a water storage chamber (4); the front part of the water storage module (1) is provided with a first water inlet (5) connected to the water storage chamber (4); the rear part of the water storage module (1) is provided with a first water outlet (6) connected to the water storage chamber (4); the first water inlet (5) is higher than the first water outlet (6); the reverse osmosis filtration module (2) is provided with a reverse osmosis filtration chamber (7); the front part of the reverse osmosis filtration module (2) is provided with a second water inlet (8) connected to the reverse osmosis filtration chamber (7); the rear part of the reverse osmosis filtration module (2) is provided with a second water inlet (8) connected to the reverse osmosis filtration chamber (7); The second water outlet (9) of the reverse osmosis filter chamber (7), the second water inlet (8) is higher than or level with the second water outlet (9), the second water inlet (8) is connected to the first water outlet (6) and has the same height; the forward osmosis filter chamber (10) is provided in the forward osmosis filter module (3), the front part of the forward osmosis filter module (3) is provided with a third water inlet (11) connected to the forward osmosis filter chamber (10), the rear part of the forward osmosis filter module (3) is provided with a third water outlet (12) connected to the forward osmosis filter chamber (10), the third water inlet (11) is higher than or level with the third water outlet (12), the third water inlet (11) and the second water outlet ( 9) are connected and have the same height; a reverse osmosis filtration structure is arranged in the reverse osmosis filtration chamber (7), the reverse osmosis filtration structure comprises a first perforated plate (13), a multi-stage reverse osmosis filtration layer and a second perforated plate (14) arranged in sequence from front to back, the multi-stage reverse osmosis filtration layer comprises a first quartz gravel layer (15), a first limestone gravel layer (16) and a second limestone gravel layer (17) arranged in sequence from front to back, the average particle size of the second limestone gravel layer (17) is larger than the average particle size of the first limestone gravel layer (16), and the average particle size of the first limestone gravel layer (16) is larger than the average particle size of the first quartz gravel layer (15); the forward osmosis filtration chamber (10) is arranged A positive filtration structure, the positive filtration structure comprising a third perforated plate (18), a multi-stage positive filtration layer and a fourth perforated plate (19) arranged in sequence from front to back, the multi-stage positive filtration layer comprising a fourth limestone gravel layer (22), a third limestone gravel layer (21) and a second quartz gravel layer (20) arranged in sequence from front to back, the average particle size of the fourth limestone gravel layer (22) being greater than the average particle size of the third limestone gravel layer (21), and the average particle size of the third limestone gravel layer (21) being greater than the average particle size of the second quartz gravel layer (20); a first aeration system is arranged in the multi-stage reverse osmosis layer, and a second aeration system is arranged in the multi-stage positive filtration layer; The multi-stage reverse osmosis filtration layer further comprises a fifth limestone gravel layer arranged behind the second limestone gravel layer (17), wherein the average particle size of the fifth limestone gravel layer is greater than the average particle size of the second limestone gravel layer (17); The multi-stage positive permeation layer further comprises a seventh limestone gravel layer arranged before the fourth limestone gravel layer (22), and the average particle size of the seventh limestone gravel layer is greater than the average particle size of the fourth limestone gravel layer (22).

2. According to the rural domestic sewage reverse rhythm treatment system described in claim 1, it is characterized in that: The multi-stage reverse osmosis filtration layer further includes a sixth limestone gravel layer disposed after the fifth limestone gravel layer, and the average particle size of the sixth limestone gravel layer is greater than the average particle size of the fifth limestone gravel layer.

3. The rural domestic sewage reverse rhythm treatment system according to claim 1, characterized in that: The multi-stage positive infiltration layer also includes an eighth limestone gravel layer disposed before the seventh limestone gravel layer, and the average particle size of the eighth limestone gravel layer is greater than the average particle size of the seventh limestone gravel layer.

4. According to the rural domestic sewage reverse rhythmic treatment system described in claim 1, the first aeration system includes a first aeration pipe (27) extending in the front-to-back direction, and the first aeration pipe (27) is provided with a plurality of first aeration holes (28) in the axial and circumferential directions. The reverse osmosis filtration module (2) also includes a first aeration connecting pipe (29) arranged vertically, and the rear end of the first aeration pipe (27) is connected to the first aeration connecting pipe (29), and the upper end of the first aeration connecting pipe (29) penetrates the cavity wall of the reverse osmosis filtration cavity (7) upward and extends outward.

5. According to the rural domestic sewage inverse rhythm treatment system described in claim 1, the second aeration system includes a second aeration pipe (30) extending in the front-to-back direction, and the second aeration pipe (30) is provided with a plurality of second aeration holes (31) in the axial and circumferential directions. The forward filtration module (3) also includes a second aeration connecting pipe (32) arranged vertically, and the rear end of the second aeration pipe (30) is connected to the second aeration connecting pipe (32), and the upper end of the second aeration connecting pipe (32) penetrates the cavity wall of the forward filtration cavity (10) upward and extends outward.

6. According to the rural domestic sewage inverse rhythm treatment system described in claim 1, a sludge trough (33) for settling sludge is provided at the bottom of the water storage chamber (4), the front side wall of the sludge trough (33) is connected to the front cavity wall of the water storage chamber (4), the rear side wall of the sludge trough (33) is gradually inclined backward from bottom to top, and the rear side wall of the sludge trough (33) is connected to the rear cavity wall of the water storage chamber (4).

7. The rural domestic sewage reverse rhythm treatment system according to claim 1, characterized in that: The water storage module (1) further comprises a cleaning port (34) communicating with the inside and outside of the water storage chamber (4) and a cleaning cover (35) for opening / closing the cleaning port (34).

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