Sewage treatment system and sewage treatment method

Abstract

The present invention discloses a sewage treatment system and a sewage treatment method, which relates to the technical field of sewage treatment. A temporary storage tank, a screen decontamination machine, a sand removal tank, a biochemical degradation tank, an MBR membrane tank and a reverse osmosis membrane device are sequentially arranged along the sewage forward direction. The biochemical degradation tank includes a first sedimentation tank, an anaerobic tank, an anoxic tank, an aerobic tank and a second sedimentation tank. The first sedimentation tank is located at the top of the second sedimentation tank. The anaerobic tank, the anoxic tank and the aerobic tank are arranged from the inside to the outside in the second sedimentation tank. The MBR membrane tank is located on one side of the second sedimentation tank, and the reverse osmosis membrane device is located on the top of the MBR membrane tank. By arranging the first sedimentation tank and the second sedimentation tank up and down, and the anoxic tank, the anaerobic tank and the aerobic tank are nested in the second sedimentation tank, the design changes the horizontal distribution of each tank body in the prior art to a vertical distribution, which greatly reduces the floor space of the entire sewage treatment system.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a sewage treatment system and a sewage treatment method. Background Art

[0002] Existing sewage treatment plants occupy a large area, so they are generally set up in conjunction with cities, factories, farms, etc. to solve daily industrial and domestic sewage, high-salt wastewater, and aquaculture sewage.

[0003] However, in the vast rural areas, due to their distance from urban agglomerations, the sewage generated in daily life is difficult to be transported to sewage treatment plants through pipes, which leads to the fact that domestic sewage in rural areas is generally discharged nearby.

[0004] Rural domestic sewage mostly comes from washing, eating, excretion and other processes. Therefore, there are fewer pollutants in the sewage. However, if it is discharged at will, it will lead to eutrophication and affect rivers, groundwater and the ecological environment.

[0005] To this end, we need to provide corresponding sewage treatment systems for the vast rural areas to avoid the occurrence of the above problems.

[0006] However, due to the restrictions of the red line of cultivated land, sewage treatment plants covering a large area are difficult to apply. Therefore, how to design a miniaturized sewage treatment system suitable for rural areas is a difficult problem currently faced by the market. Summary of the invention

[0007] In view of the above defects, the purpose of the present invention is to provide a sewage treatment system and a sewage treatment method, aiming to solve the problem that the sewage treatment system in the prior art is difficult to miniaturize.

[0008] In order to solve the above technical problems, the technical solution of the present invention is:

[0009] A sewage treatment system is provided with a temporary storage tank, a screen decontamination machine, a sand removal tank, a biochemical degradation tank, an MBR membrane tank and a reverse osmosis membrane device in sequence along the direction of sewage flow. The biochemical degradation tank comprises a first sedimentation tank, an anaerobic tank, an anoxic tank, an aerobic tank and a second sedimentation tank. The first sedimentation tank is located at the top of the second sedimentation tank. The anaerobic tank, the anoxic tank and the aerobic tank are arranged from the inside to the outside in the second sedimentation tank. The MBR membrane tank is located at one side of the second sedimentation tank. The reverse osmosis membrane device is located at the top of the MBR membrane tank.

[0010] Wherein, the first sedimentation tank includes a floating tank and a static tank, the floating tank is located in the static tank, the anaerobic tank is connected to the static tank by a pipeline, a dirt removal scraper and a rotating column are installed on the top of the floating tank, a first cavity is vertically arranged in the rotating column, the dirt removal scraper includes a first plate body and a second plate body, an arc plate is arranged between the first plate body and the second plate body, the concave surface of the arc plate faces away from the top of the floating tank, a plurality of sewage suction ports are arranged on the concave surface, a second cavity is horizontally arranged in the first plate body, one end of the first plate body is connected to the side wall of the rotating column, one end of the second cavity is communicated with the first cavity, the second cavity and the sewage suction port are connected by a pipeline, and an oil suction pipeline is rotatably connected to the top of the rotating column.

[0011] Among them, the rotating column includes an oil pumping section and a mud pumping section, the first cavity is located in the oil pumping section, and a third cavity is arranged in the mud pumping section. The outer wall of the mud pumping section is provided with a first spiral blade, a first mud pumping head, a second spiral blade and a second mud pumping head from top to bottom, the first spiral blade and the first mud pumping head are both located at the bottom of the floating pool, the second spiral blade and the second mud pumping head are both located at the bottom of the static pool, a number of mud pumping ports are arranged on the side walls of the first mud pumping head and the second mud pumping head, the mud pumping ports are connected to the third cavity, and the end of the mud pumping section away from the oil pumping section is rotatably connected to a mud pumping pipeline.

[0012] Among them, a first motor is installed between the first sedimentation tank and the second sedimentation tank, a driving wheel is installed at the power output end of the first motor, a power wheel matching the driving wheel is installed on the side wall of the rotating column, and the driving wheel is connected to the power wheel belt.

[0013] Among them, a strain temporary storage device is installed inside the anaerobic tank, and the strain temporary storage device includes a fixed warehouse, a plurality of strain warehouses are suspended at the bottom of the fixed warehouse, a plurality of exchange holes are arranged on the side wall of the strain warehouse, and a liquid inlet pipe is connected to the top of the fixed warehouse.

[0014] Among them, the temporary storage device for bacterial strains also includes a power column and a plurality of sliding rods, the sliding rods are arranged around the power column, the power column includes a threaded section and a collecting section, the middle area of ​​the fixed bin is threadedly connected to the threaded section, the fixed bin is slidably connected to the sliding rods, the collecting section is located between the threaded section and the bottom of the anaerobic tank, and a third spiral blade is installed on the side wall of the collecting section.

[0015] Among them, a card table and an opening and closing plate are installed at the bottom of the culture bin, one end of the opening and closing plate is hinged to the culture bin, and the end of the opening and closing plate facing the bottom of the anaerobic tank is carded with the card table. A mud storage tank is arranged at the bottom of the anaerobic tank, and the mud storage tank is arranged opposite to the culture bin.

[0016] Among them, a limit seat is set at the bottom of the anoxic tank, and the limit seat includes a first trough body and a second trough body. The inner diameter of the first trough body is larger than the inner diameter of the second trough body. The first trough body is located between the second trough body and the anaerobic tank. A support platform is installed between the first trough body and the anaerobic tank. The side wall of the support platform is provided with a mud hole, and the inner wall of the second trough body is provided with a mud extraction hole.

[0017] Among them, a fixing seat is provided at the bottom of the aerobic pool, a collecting tank is provided in the middle area of ​​the fixing seat, a fixing platform is installed between the fixing seat and the anoxic pool, holes are opened on the side wall of the fixing platform, a part of the power column extends through the anoxic pool to the collecting tank, and a fifth spiral blade is provided between the outer wall of the power column and the collecting tank.

[0018] A sewage treatment method comprises the following steps:

[0019] Step 1: sewage pretreatment;

[0020] Domestic sewage is collected in a temporary storage tank through drainage pipes, and then, under the action of the screen decontamination machine, larger garbage and debris are transported to the garbage bin, and sewage is transported to the desanding tank for desanding;

[0021] Step 2, initial settlement;

[0022] The sewage is transported from the desanding tank to the first sedimentation tank for sedimentation and foam removal. Flocculants are added to the first sedimentation tank, and the grease and foam on the surface of the sewage are skimmed by a decontamination scraper. The sewage is left for 3-6 hours, and then the sewage after preliminary sedimentation is sent to the biochemical degradation tank.

[0023] Step three, biochemical sedimentation;

[0024] After reaching the biochemical degradation tank, the sewage first reaches the anaerobic tank, where anaerobic bacteria are added and air is pumped out, and then the tank is left standing for 5-8 hours, maintaining a temperature of 22-32°C; then, the sewage in the anaerobic tank is transported to the anoxic tank, bacteria are added, a low-oxygen environment is maintained, and the tank is left standing for 3-5 hours; then, the sewage in the anoxic tank is sent to the aerobic tank, where aerobic bacteria are added, and oxygen-rich air is continuously introduced into the aerobic tank for 4-6 hours; finally, the sewage in the aerobic tank is sent to the second sedimentation tank, and the sewage is irradiated with ultraviolet rays at the same time;

[0025] Step 4, membrane filtration;

[0026] After the sewage is allowed to stand in the second sedimentation tank for 3-5 hours, it is pumped into the MBR membrane pool. Chlorine is introduced into the MBR membrane pool. After being filtered through the MBR membrane, the sewage becomes recycled water, which is then sent to the reverse osmosis membrane pool. The reverse osmosis membrane pool separates the recycled water into pure water and high-salt wastewater. The pure water is discharged into the natural environment, and the high-salt wastewater is sent to the high-salt wastewater pool.

[0027] After adopting the above technical solution, the beneficial effects of the present invention are:

[0028] First, by arranging the first sedimentation tank and the second sedimentation tank up and down, and nesting the anoxic tank, anaerobic tank and aerobic tank in the second sedimentation tank, this design changes the horizontal distribution of each tank in the existing technology to a vertical distribution, greatly reducing the footprint of the entire sewage treatment system. Second, the anoxic tank, anaerobic tank and aerobic tank are all equipped with sludge reservation mechanisms. This design allows a portion of the bacteria in the three tanks to be retained, thereby avoiding the design of a return pipeline and further reducing the overall volume. Third, the collected domestic sewage has undergone several steps such as pretreatment, primary sedimentation, biochemical sedimentation and membrane filtration in turn, ensuring that the quality of the treated effluent meets the discharge standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the sewage treatment flow chart;

[0030] Figure 2 This is the structural diagram of the biochemical degradation pool;

[0031] Figure 3 This is the structural diagram of the first sedimentation tank;

[0032] Figure 4 It is the structural diagram of the rotating column;

[0033] Figure 5 A three-dimensional diagram of a dirt removal scraper;

[0034] Figure 6 The structural diagram of the decontamination scraper;

[0035] Figure 7 This is the structural diagram of the aerobic pool;

[0036] Figure 8 This is the structural diagram of the anaerobic tank;

[0037] Fig. 9 It is a cross-sectional view of the bacterial seed bin;

[0038] Fig.10 is a structural diagram of the support arm;

[0039] Fig.11 Diagram of the structure of the anoxic pool;

[0040] Fig.12 Structural diagram of the delivery tube.

[0041] In the figure:

[0042] 1-temporary storage tank, 2-grid decontamination machine, 3-sand removal tank, 4-biochemical degradation tank, 5-MBR membrane tank, 6-reverse osmosis membrane device,

[0043] 41-first sedimentation tank, 411-floating tank, 412-static tank, 413-scraper for removing dirt, 4131-first plate, 4132-second plate, 4133-arc plate, 4134-sewage suction port, 4135-second cavity, 414-rotating column, 4141-oil pumping section, 4142-mud pumping section, 4143-first spiral blade, 4144-first mud pumping head, 4145- second spiral blade, 4146-second mud pumping head, 4147-mud pumping pipe, 415-oil suction pipe, 416-first motor, 4161-driving wheel, 4162-power wheel, 417-scraper, 4171-scraper frame, 4172-fixed arm, 418-feeding mechanism, 4181-feeding frame, 4182-annular feeding pipe, 4183-connecting arm, 4184-feeding port;

[0044] 42-second sedimentation tank, 421-ultraviolet lamp;

[0045] 43-anaerobic tank, 431-fixed chamber, 432-bacteria chamber, 4321-exchange hole, 4322-opening and closing plate, 4323-card table, 433-liquid inlet pipe, 435-power column, 4350-sliding rod, 4351-threaded section, 4352-collecting section, 4353-third spiral blade, 436-mud storage tank, 437-support arm, 4371-support ring, 4372-mud storage chamber;

[0046] 44-anoxic tank, 441-limiting seat, 4411-first tank body, 4412-second tank body, 442-supporting platform, 4421-mud hole, 443-fourth spiral blade, 444-first mud storage chamber, 445-first annular pipe, 446-first mud pump, 447-mud delivery pipeline, 4471-delivery hole, 448-delivery cylinder, 4481-exchange channel, 4482-supporting chamber, 449-delivery pipeline;

[0047] 45-aerobic tank, 451-fixed seat, 4511-collecting tank, 452-fixed platform, 453-fifth spiral blade, 454-second mud storage tank, 455-second annular pipe, 456-second mud pump, 457-annular discharge pipe, 4571-discharge head, 458-aeration pipe, 459-second motor. DETAILED DESCRIPTION

[0048] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0049] Example:

[0050] like Figure 1-Figure 12As shown, a sewage treatment system is provided with a temporary storage tank 1, a screen decontamination machine 2, a desanding tank 3, a biochemical degradation tank 4, an MBR membrane tank 5 and a reverse osmosis membrane device 6 in sequence along the direction of the sewage. The temporary storage tank 1 is used to store sewage from the pipeline network. Since the sewage at this time is mixed with various debris, in order to avoid affecting the subsequent treatment, we need to use the screen decontamination machine 2 to salvage and filter these debris. After the sewage passes through the screen decontamination machine 2, the large-sized debris it carries is removed and sent to the garbage storage bin, waiting for the garbage transfer vehicle to send it to the garbage treatment site. Although the sewage at this time does not carry large-sized debris, it contains large particles such as gravel and stones. The gravel and stones will impact the inner wall of the sewage treatment equipment in the process of following the flow of sewage, accelerating the wear of the sewage treatment equipment. For this reason, the sewage enters the desanding tank 3 after being treated by the screen decontamination machine 2. The flow rate of the sewage in the desanding tank 3 will slow down. At this time, the stones and gravel will gradually settle at the bottom of the desanding tank 3, waiting for recycling.

[0051] After the sewage is treated by the screen decontamination machine 2 and the sand removal pool 3, the large-mass and large-size impurities inside it have been basically removed, but the small-size impurities and nutrient-rich substances in the sewage still make the sewage turbid. Therefore, we need to further treat the sewage.

[0052] In this regard, this solution introduces a biochemical degradation pool 4. Figure 2 As shown, the biochemical degradation tank 4 includes a first sedimentation tank 41, an anaerobic tank 43, an anoxic tank 44, an aerobic tank 45 and a second sedimentation tank 42. The first sedimentation tank 41 is used to place the sewage from the desander 3. After the sewage is placed for a period of time, the oil and foam on the surface of the sewage are scraped off, and flocculants are added into the first sedimentation tank 41 to force the inorganic salt ions to condense and settle, thereby reducing the salt content in the sewage and accelerating the sedimentation of small particles in the sewage.

[0053] After standing, the sewage in the first sedimentation tank 41 enters the anaerobic tank 43, the anoxic tank 44, the aerobic tank 45 and the second sedimentation tank 42 in turn. The function of the anaerobic tank 43 is to decompose phosphates through anaerobic bacteria such as polyphosphate bacteria, decompose macromolecular organic matter into small molecular organic matter, convert insoluble organic matter into soluble organic matter, and release ammonia nitrogen and phosphorus. The function of the anoxic tank 44 is denitrification, and denitrifying bacteria reduce nitrates to nitrogen gas. The function of the aerobic tank 45 is to decompose small organic molecules, some of which are absorbed by microorganisms, and some of which are decomposed into carbon dioxide and water, and ammonia nitrogen is oxidized into nitrate nitrogen, and phosphorus is also absorbed to prevent eutrophication problems after the sewage is discharged. The function of the second sedimentation tank 42 is to sterilize the sewage from the aerobic tank 45, and to stand again to collect sludge in the sewage.

[0054] In this solution, in order to reduce the occupied area, the first sedimentation tank 41 is located on the top of the second sedimentation tank 42, and the anaerobic tank 43, the anoxic tank 44 and the aerobic tank 45 are arranged from the inside to the outside in the second sedimentation tank 42. The first sedimentation tank 41 and the second sedimentation tank 42 are distributed up and down, while the anaerobic tank 43, the anoxic tank 44 and the aerobic tank 45 are nested from the inside to the outside. This design reduces the occupied area of ​​the sewage treatment equipment by increasing the height of the sewage treatment system.

[0055] Similarly, the MBR membrane pool 5 is located on one side of the second sedimentation tank 42, and the reverse osmosis membrane device 6 is located on the top of the MBR membrane pool 5. The MBR membrane pool 5 performs preliminary filtration on the sewage from the second sedimentation tank 42, removes small particle impurities in the sewage, and converts the sewage into reclaimed water. The reverse osmosis membrane device 6 further processes the reclaimed water, and converts the reclaimed water into high-salt wastewater and purified water, wherein the high-salt wastewater is collected and sent to the required chemical plant, and the purified water is directly discharged to the outside.

[0056] In order to facilitate the first sedimentation tank 41 to simultaneously take into account the two functions of scraping off grease foam and flocculation sedimentation, the first sedimentation tank 41 includes a floating tank 411 and a static tank 412. The floating tank 411 is used to remove grease foam, and the static tank 412 is used for flocculation sedimentation.

[0057] In order to reduce the volume, the floating tank 411 is located in the static tank 412, and the anaerobic tank 43 is connected to the static tank 412 by a pipeline. A dirt-removing scraper 413 and a rotating column 414 are installed on the top of the floating pool 411. A first cavity is vertically arranged in the rotating column 414. The dirt-removing scraper 413 includes a first plate 4131 and a second plate 4132. An arc plate 4133 is arranged between the first plate 4131 and the second plate 4132. The concave surface of the arc plate 4133 faces away from the top of the floating pool 411. A plurality of dirt suction ports 4134 are arranged on the concave surface. A second cavity 4135 is horizontally arranged in the first plate 4131. One end of the first plate 4131 is connected to the side wall of the rotating column 414. One end of the second cavity 4135 is connected to the first cavity. The second cavity 4135 is connected to the dirt suction port 4134 by a pipeline. The top of the rotating column 414 is rotatably connected to an oil suction pipeline 415. Figure 3-6As shown, in this solution, the height of the second plate 4132 is lower than that of the first plate 4131. When in use, the top of the second plate 4132 is level with the surface of the sewage in the floating pool 411, while the arc plate 4133 is lower than the surface of the sewage. Since grease and foam float on the surface of the sewage, slightly above the water surface, when the rotating column 414 drives the decontamination scraper 413 to rotate, the grease and foam will jump over the top of the second plate 4132 to reach the concave surface of the arc plate 4133, and then the sewage suction port 4134 will send the grease, foam and part of the sewage to the second cavity 4135, and then these pollutants will reach the first cavity and the oil suction pipe 415 along the second cavity 4135, and finally, the foam and grease will reach the oil storage bin along the oil suction pipe 415 for temporary storage. When the grease in the oil storage bin reaches a certain amount, the garbage transfer vehicle will transfer it to the garbage disposal station for final treatment.

[0058] In order to facilitate the extraction of silt accumulated at the bottom of the static pool 412 and the floating pool 411, the rotating column 414 includes an oil pumping section 4141 and a mud pumping section 4142, the first cavity is located in the oil pumping section 4141, and a third cavity is arranged in the mud pumping section 4142, and the outer wall of the mud pumping section 4142 is provided with a first spiral blade 4143, a first mud pumping head 4144, a second spiral blade 4145 and a second mud pumping head 4146 from top to bottom, the first spiral blade 4143 and the first mud pumping head 4144 are both located at the bottom of the floating pool 411, the second spiral blade 4145 and the second mud pumping head 4146 are both located at the bottom of the static pool 412, and a plurality of mud pumping ports are arranged on the side walls of the first mud pumping head 4144 and the second mud pumping head 4146, and the mud pumping ports are connected to the third cavity, and the end of the mud pumping section 4142 away from the oil pumping section 4141 is rotatably connected to a mud pumping pipe 4147. It is worth noting that the oil pumping section 4141 and the mud pumping section 4142 are not connected.

[0059] The above design allows the static pool 412 and the floating pool 411 to share a mud pumping pipe 4147. When the rotating column 414 rotates, the first spiral blade 4143, the first mud pumping head 4144, the second spiral blade 4145 and the second mud pumping head 4146 will all rotate with the rotating column 414. At this time, the sludge at the bottom of the floating pool 411 is driven by the first spiral blade 4143 to gather toward the first mud pumping head 4144, while the sludge at the bottom of the static pool 412 is driven by the second spiral blade 4145 to gather toward the second mud pumping head 4146. One end of the mud pumping pipe 4147 is connected to a mud pumping machine. When the mud pumping machine is turned on, the first mud pumping head 4144 and the second mud pumping head 4146 begin to extract the sludge at the bottom of the static pool 412 and the floating pool 411, and transport the sludge to the mud pumping pipe 4147 through the third cavity, and finally transport the sludge to the mud storage equipment to wait for transportation to the fertilizer factory.

[0060] In order to facilitate the rotation of the rotating column 414, a first motor 416 is installed between the first sedimentation tank 41 and the second sedimentation tank 42, and a driving wheel 4161 is installed at the power output end of the first motor 416. A power wheel 4162 matching the driving wheel 4161 is installed on the side wall of the rotating column 414, and the driving wheel 4161 is connected to the power wheel 4162 by a belt.

[0061] In order to facilitate the sludge at the bottom of the floating pool 411 to reach the first sludge pumping head 4144, a scraper 417 and a scraper frame 4171 are also installed in the floating pool 411. The scraper frame 4171 is arranged around the rotating column 414. A fixed arm 4172 is installed between the scraper 417 and the scraper frame 4171 to fix the scraper 417. The bottom of the floating pool 411 in this solution is conical. In order to better fit the bottom of the floating pool 411, the lengths of the fixed arms 4172 gradually increase from the side wall of the floating pool 411 toward the axis of the floating pool 411. This design makes the heights of the scraper 417 different, so that it can fit the bottom of the floating pool 411.

[0062] In order to facilitate the feeding of flocculants into the static pool 412, a feeding mechanism 418 is provided on the top of the static pool 412. The feeding mechanism 418 includes a feeding rack 4181 and an annular feeding pipe 4182. A connecting arm 4183 is provided between the annular feeding pipe 4182 and the feeding rack 4181. The annular feeding pipe 4182 is provided around the floating pool 411. The feeding rack 4181 is connected to the side wall of the rotating column 414. A medicine box is placed on the top of the feeding rack 4181. A plurality of feeding ports 4184 are provided at the bottom of the annular feeding pipe 4182. When the rotating column 414 rotates, the feeding rack 4181 will be driven to rotate together, and the annular feeding pipe 4182 will also rotate with the feeding rack 4181. At the same time, the flocculants stored in the medicine box are sent to the annular feeding pipe 4182 through the pipeline, and then sent to the static pool 412 through the feeding port 4184. This design allows the flocculant to cover a larger area during the falling process, so that the flocculant and sewage can be mixed more thoroughly.

[0063] like Figure 7-9 As shown, in order to facilitate the introduction of anaerobic bacteria into the anaerobic tank 43, a bacteria temporary storage device is installed inside the anaerobic tank 43, and the bacteria temporary storage device includes a fixed bin 431, and a plurality of bacteria bins 432 are suspended at the bottom of the fixed bin 431. A plurality of exchange holes 4321 are arranged on the side wall of the bacteria bin 432, and a liquid inlet pipe 433 is connected to the top of the fixed bin 431. The liquid inlet pipe 433 delivers the anaerobic bacteria and the culture solution to the fixed bin 431, and then the fixed bin 431 distributes them to the bacteria bin 432, and then the anaerobic bacteria will overflow into the anaerobic tank 43 through the exchange holes 4321. Among them, the plurality of bacteria bins 432 increase the diffusion range of the anaerobic bacteria, thereby accelerating the sewage treatment speed of the anaerobic tank 43.

[0064] In order to speed up the diffusion of anaerobic bacteria in sewage, we can move the bacterial seed bin 432 up and down so that the bacterial seed bin 432 is at different heights. For this purpose, the bacterial seed temporary storage device also includes a power column 435 and a plurality of sliding rods 4350. The sliding rods 4350 are arranged around the power column 435. The power column 435 includes a threaded section 4351 and a collection section 4352. The middle area of ​​the fixed bin 431 is threadedly connected with the threaded section 4351. The fixed bin 431 is slidably connected with the sliding rod 4350. The collection section 4352 is located between the threaded section 4351 and the bottom of the anaerobic tank 43. A third spiral blade 4353 is installed on the side wall of the collection section 4352. Since the fixed bin 431 is threadedly connected with the threaded section 4351, the power column 435 will drive the fixed bin 431 to move up and down when it rotates. This design allows the bacteria in the bacterial seed bin 432 to overflow to different heights in the sewage, completing the diffusion of the anaerobic bacteria. When the power column 435 rotates, the third spiral blade 4353 will also rotate, which will drive the sludge to gather toward the bottom to facilitate the discharge of the sludge.

[0065] The anaerobic bacteria in the anaerobic tank 43 will decrease as the water is transferred and the sludge is removed. For this reason, a common practice is to supplement the anaerobic bacteria, or to extract the sludge in the rear tank body and return it to the anaerobic tank 43, so that the anaerobic bacteria in the anaerobic tank 43 are maintained at a certain amount. However, in addition to the above two methods, we can also adopt a third method, that is, to retain a certain amount of sludge before draining the water and sludge from the anaerobic tank 43. Since the sludge is rich in nutrients and is a natural bacterial culture medium, therefore, retaining a certain amount of sludge in advance can retain the corresponding bacterial species, thereby accelerating the spread and reproduction of the bacterial species during the subsequent water intake process.

[0066] To this end, a mud storage tank 436 is provided at the bottom of the anaerobic tank 43, and the mud storage tank 436 is arranged opposite to the bacterial seed bin 432. A clamping platform 4323 and an opening and closing plate 4322 are installed at the bottom of the bacterial seed bin 432. One end of the opening and closing plate 4322 is hinged to the bacterial seed bin 432, and one end of the opening and closing plate 4322 facing the bottom of the anaerobic tank 43 is clamped to the clamping platform 4323. The bacterial seed bin 432 will enter the mud storage tank 436 during the falling process, and the mud storage tank 436 is full of sludge. The opening and closing plate 4322 in this solution is hinged to the bottom of the bacterial seed bin 432, and the opening and closing plate 4322 is opened toward the inside of the bacterial seed bin 432. Therefore, during the falling process of the bacterial seed bin 432, the sludge will squeeze the opening and closing plate 4322, forcing the opening and closing plate 4322 to open, and the sludge will enter the bacterial seed bin 432. When the culture bin 432 rises, the sludge slides down under the influence of gravity, which will drive the opening and closing plate 4322 to close. Due to the obstruction of the card platform 4323, the opening and closing plate 4322 cannot be further rotated downward, so the sludge will remain in the culture bin 432, completing the work of reserving the culture.

[0067] In order to facilitate the fixing of the sliding rod 4350, a support arm 437 cooperating with the sliding rod 4350 is provided in the anaerobic tank 43, one end of the support arm 437 is connected to the side wall of the anaerobic tank 43, the other end of the support arm 437 is connected to a support ring 4371, and the top of the power column 435 is rotatably connected to the support ring 4371. In order to facilitate further retention of bacterial strains, a mud storage cavity 4372 is provided on the top of the support arm 437. This design enables the support arm 437 to accumulate a portion of sludge and preserve bacterial strains. When sewage is re-injected, the sewage will merge with this portion of sludge, accelerating the diffusion of anaerobic bacteria.

[0068] In order to facilitate the discharge of sludge in the anaerobic chamber, the bottom of the anaerobic chamber is conical, and a pipe for pumping sludge is installed at the bottom, and the other end of the pipe needs to be connected to a pump for pumping sludge.

[0069] It is worth noting that the liquid inlet pipe 433 in this solution is an elastic hose. In order to avoid hindering the upward and downward movement of the fixed chamber 431, a margin is left in the liquid inlet pipe 433.

[0070] like Figure 11-12 As shown, in order to conveniently fix the anaerobic tank 43 in the anoxic tank 44, a limit seat 441 is provided at the bottom of the anoxic tank 44, and the limit seat 441 includes a first tank body 4411 and a second tank body 4412. The inner diameter of the first tank body 4411 is larger than the inner diameter of the second tank body 4412. The first tank body 4411 is located between the second tank body 4412 and the anaerobic tank 43. A support platform 442 is installed between the first tank body 4411 and the anaerobic tank 43. A mud hole 4421 is provided on the side wall of the support platform 442, and a mud extraction hole is provided on the inner wall of the second tank body 4412. The purpose of providing the mud hole 4421 on the side wall of the support platform 442 is to facilitate the movement of the sludge in the anoxic tank 44 toward the second tank body 4412, and finally to transport it to the sludge storage device through the mud extraction hole of the second tank body 4412.

[0071] In order to facilitate the collection of sludge in the anoxic tank 44 in the second tank body 4412, a portion of the power column 435 extends to the second tank body 4412, and a fourth spiral blade 443 is provided between the power column 435 and the second tank body 4412. The power column 435 drives the fourth spiral blade 443 to rotate during the rotation process, and the sludge follows the fourth spiral blade 443 to collect toward the sludge extraction hole in the second tank body 4412.

[0072] In order to facilitate the retention of the bacteria in the anaerobic tank 43, the top of the limiting seat 441 is recessed toward the bottom of the limiting seat 441 to form a first mud storage chamber 444, the first mud storage chamber 444 is annular, and the first mud storage chamber 444 is arranged around the first trough body 4411, a first annular tube 445 is arranged in the first mud storage chamber 444, and a plurality of first through holes are opened on the outer wall of the first annular tube 445, a first mud pump 446 is installed inside the limiting seat 441, one end of the first mud pump 446 is connected to the first annular tube 445, the other end of the first mud pump 446 is connected to a mud delivery pipe 447, and the other end of the mud delivery pipe 447 is located in the anoxic tank 44. Part of the sludge in the anoxic tank 44 will settle in the first mud storage chamber 444. When necessary, the first mud pump 446 is started to extract the sludge accumulated in the first mud storage chamber 444 through the first annular pipe 445 buried at the bottom of the first mud storage chamber 444, and then spray it into the anoxic tank 44 through the mud delivery pipe 447.

[0073] Furthermore, a delivery cylinder 448 is fixed on the side wall of the anaerobic tank 43, and a plurality of exchange channels 4481 are arranged on the side wall of the delivery cylinder 448. A plurality of support chambers 4482 are arranged from top to bottom in the delivery cylinder 448. One end of the mud delivery pipe 447 is located in the delivery cylinder 448, and a delivery hole 4471 matching with the support chamber 4482 is arranged on the side wall of the mud delivery pipe 447. The mud delivery pipe 447 delivers the sludge with the bacterial strain to the support chamber 4482 of the delivery cylinder 448 through the delivery hole 4471, and each layer of the support chamber 4482 gradually disperses the bacterial strain into the sewage through the exchange channel 4481. In order to facilitate the delivery of bacterial strains from the outside to the anoxic tank 44, a delivery pipe 449 is connected to the top of the delivery cylinder 448.

[0074] In order to facilitate the flow of sewage between different tanks, the anoxic tank 44 is connected to the anaerobic tank 43 through a pipeline, and the aerobic tank 45 is connected to the anoxic tank 44 through a pipeline.

[0075] In order to conveniently fix the anoxic tank 44 in the aerobic tank 45, a fixing seat 451 is provided at the bottom of the aerobic tank 45, a collecting tank 4511 is provided in the middle area of ​​the fixing seat 451, a fixing platform 452 is installed between the fixing seat 451 and the anoxic tank 44, a hole is provided on the side wall of the fixing platform 452, a part of the power column 435 extends through the anoxic tank 44 to the collecting tank 4511, and a fifth spiral blade 453 is provided between the outer wall of the power column 435 and the collecting tank 4511. After accumulating to a certain amount, the sludge passes through the holes on the fixing platform 452 to the collecting tank 4511, and then moves toward the bottom of the collecting tank 4511 driven by the fifth spiral blade 453. Since a suction pipe is installed on the side wall of the collecting tank 4511, the sludge in the collecting tank 4511 can be sent to the sludge storage device through the suction pipe.

[0076] In order to reserve the bacterial strains in the aerobic tank 45, a second mud storage tank 454 is arranged on the top of the fixed seat 451. The second mud storage tank 454 is annular. A second annular pipe 455 is installed in the second mud storage tank 454. A channel for pumping mud is provided on the outer wall of the second annular pipe 455. An annular discharge pipe 457 is installed in the aerobic tank 45. A plurality of discharge heads 4571 are installed on the annular discharge pipe 457. The annular discharge pipe is arranged around the anoxic tank 44. A second mud pump 456 is arranged in the fixed seat 451. One end of the second mud pump 456 is connected to the second annular pipe 455, and the other end of the second mud pump 456 is connected to the annular discharge pipe 457. The second mud pump 456 delivers the sludge in the second mud storage tank 454 to the second annular pipe 455, and then discharges it into the sewage through the discharge head 4571. At this time, the sludge will mix with the sewage during the falling process, so that the bacterial strains spread to the entire aerobic tank 45.

[0077] Preferably, an aeration pipe 458 is installed in the aerobic tank 45 , and the aeration pipe 458 is arranged around the anoxic tank 44 .

[0078] In order to facilitate the rotation of the power column 435, the aerobic tank 45 is connected to the second sedimentation tank 42 through a pipeline. A positioning seat is installed between the aerobic tank 45 and the second sedimentation tank 42. A second motor 459 is installed in the positioning seat. The power output end of the second motor 459 is connected to one end of the power column 435.

[0079] A waterproof cover is installed on the inner wall of the second sedimentation tank 42, and a plurality of ultraviolet lamps 421 are installed between the waterproof cover and the inner wall of the second sedimentation tank 42. Since this system is a small sewage treatment system, it is difficult to sterilize with a large amount of chlorine, so this solution uses ultraviolet irradiation to sterilize the sewage.

[0080] A sewage treatment method comprises the following steps:

[0081] Step 1: sewage pretreatment;

[0082] Domestic sewage is collected in the temporary storage tank 1 through the drainage pipe, and then under the action of the screen decontamination machine 2, the larger garbage and debris are transported to the garbage bin, and the sewage is transported to the desanding tank 3 for desanding;

[0083] Step 2, initial settlement;

[0084] The sewage is transported from the desanding tank 3 to the first sedimentation tank 41 for sedimentation and foam removal. Flocculant is added to the first sedimentation tank 41, and the grease and foam on the surface of the sewage are skimmed by the decontamination scraper 413. The sewage is left for 3-6 hours, and then the sewage after preliminary sedimentation is sent to the biochemical degradation tank 4.

[0085] Step three, biochemical sedimentation;

[0086] After reaching the biochemical degradation tank 4, the sewage first reaches the anaerobic tank 43, into which anaerobic bacteria are added and air is pumped, and then the sewage is left standing for 5-8 hours, maintaining a temperature of 22-32°C; then, the sewage in the anaerobic tank 43 is transported to the anoxic tank 44, into which bacteria are added and a low oxygen environment is maintained, and the sewage is left standing for 3-5 hours; then, the sewage in the anoxic tank 44 is transported to the aerobic tank 45, into which aerobic bacteria are added, and oxygen-rich air is continuously introduced into the aerobic tank 45, and the sewage is left standing for 4-6 hours; finally, the sewage in the aerobic tank 45 is transported to the second sedimentation tank 42, and the sewage is irradiated with ultraviolet rays at the same time;

[0087] Step 4, membrane filtration;

[0088] The sewage is allowed to stand in the second sedimentation tank 42 for 3-5 hours and then pumped into the MBR membrane tank 5. Chlorine is introduced into the MBR membrane tank 5. The sewage becomes recycled water after being filtered through the MBR membrane. The recycled water is then sent to the reverse osmosis membrane tank. The reverse osmosis membrane tank separates the recycled water into pure water and high-salt wastewater. The pure water is discharged into the natural environment, and the high-salt wastewater is sent to the high-salt wastewater tank.

[0089] In summary, the advantages of this solution are: First, by arranging the first sedimentation tank 41 and the second sedimentation tank 42 up and down, and nesting the anoxic tank 44, the anaerobic tank 43 and the aerobic tank 45 in the second sedimentation tank 42, this design changes the horizontal distribution of each tank body in the prior art to a vertical distribution, which greatly reduces the footprint of the entire sewage treatment system. Second, the anoxic tank 44, the anaerobic tank 43 and the aerobic tank 45 are all equipped with sludge reservation mechanisms. This design allows a portion of the bacteria in the three tanks to be retained, thereby avoiding the design of a return line, and further reducing the overall volume. Third, the collected domestic sewage has undergone several steps such as pretreatment, primary sedimentation, biochemical sedimentation and membrane filtration in turn, ensuring that the quality of the treated sewage meets the discharge standards.

[0090] The present invention is not limited to the above-mentioned specific implementation modes. Various changes made by ordinary technicians in this field based on the above-mentioned concepts without creative work are all within the protection scope of the present invention.

Claims

1. A sewage treatment system, comprising a temporary storage tank (1), a screen decontamination machine (2), a sand removal tank (3), a biochemical degradation tank (4), an MBR membrane tank (5) and a reverse osmosis membrane device (6) arranged in sequence along the direction of sewage flow, characterized in that: The biochemical degradation tank (4) comprises a first sedimentation tank (41), an anaerobic tank (43), an anoxic tank (44), an aerobic tank (45) and a second sedimentation tank (42); the first sedimentation tank (41) is located at the top of the second sedimentation tank (42); the anaerobic tank (43), the anoxic tank (44) and the aerobic tank (45) are arranged from the inside to the outside in the second sedimentation tank (42); the MBR membrane tank (5) is located at one side of the second sedimentation tank (42); and the reverse osmosis membrane device (6) is located at the top of the MBR membrane tank (5); A bacterial strain temporary storage device is installed inside the anaerobic tank (43), and the bacterial strain temporary storage device comprises a fixed bin (431), a plurality of bacterial strain bins (432) are suspended at the bottom of the fixed bin (431), a plurality of exchange holes (4321) are arranged on the side wall of the bacterial strain bin (432), and a liquid inlet pipe (433) is connected to the top of the fixed bin (431); The bacterial strain temporary storage device further comprises a power column (435) and a plurality of sliding rods (4350), wherein the sliding rods (4350) are arranged around the power column (435), the power column (435) comprises a threaded section (4351) and a collecting section (4352), a middle area of ​​the fixed bin (431) is threadedly connected to the threaded section (4351), the fixed bin (431) is slidably connected to the sliding rods (4350), the collecting section (4352) is located between the threaded section (4351) and the bottom of the anaerobic tank (43), and a third spiral blade (4353) is installed on the side wall of the collecting section (4352); A clamping platform (4323) and an opening and closing plate (4322) are installed at the bottom of the bacterial seed bin (432); one end of the opening and closing plate (4322) is hinged to the bacterial seed bin (432); one end of the opening and closing plate (4322) facing the bottom of the anaerobic tank (43) is clamped to the clamping platform (4323); a mud storage tank (436) is arranged at the bottom of the anaerobic tank (43); and the mud storage tank (436) is arranged opposite to the bacterial seed bin (432).

2. The sewage treatment system according to claim 1, characterized in that: The first sedimentation tank (41) comprises a floating tank (411) and a static tank (412), the floating tank (411) is located in the static tank (412), the anaerobic tank (43) is connected to the static tank (412) by a pipeline, a decontamination scraper and a rotating column (414) are installed on the top of the floating tank (411), a first cavity is vertically arranged in the rotating column (414), the decontamination scraper (413) comprises a first plate body (4131) and a second plate body (4132), an arc plate (4131) is arranged between the first plate body (4131) and the second plate body (4132), and a first cavity is vertically arranged in the rotating column (414). 133), the concave surface of the arc-shaped plate (4133) faces a direction away from the top of the floating pool (411), and a plurality of sewage suction ports (4134) are arranged on the concave surface; a second cavity (4135) is horizontally arranged in the first plate body (4131); one end of the first plate body (4131) is connected to the side wall of the rotating column (414), one end of the second cavity (4135) is communicated with the first cavity, a pipeline is connected between the second cavity (4135) and the sewage suction port (4134), and the top of the rotating column (414) is rotatably connected to an oil suction pipeline (415).

3. The sewage treatment system according to claim 2, characterized in that: The rotating column (414) comprises an oil pumping section (4141) and a mud pumping section (4142), the first cavity is located in the oil pumping section (4141), a third cavity is arranged in the mud pumping section (4142), and the outer wall of the mud pumping section (4142) is provided with a first spiral blade (4143), a first mud pumping head (4144), a second spiral blade (4145) and a second mud pumping head (4146) in order from top to bottom, the first spiral blade (4143) The first mud pumping head (4144) is located at the bottom of the floating pool (411), the second spiral blade (4145) and the second mud pumping head (4146) are located at the bottom of the static pool (412), a plurality of mud pumping ports are provided on the side walls of the first mud pumping head (4144) and the second mud pumping head (4146), and the mud pumping ports are connected to the third cavity, and one end of the mud pumping section (4142) away from the oil pumping section (4141) is rotatably connected to a mud pumping pipe (4147).

4. The sewage treatment system according to claim 3, characterized in that: A first motor (416) is installed between the first sedimentation tank (41) and the second sedimentation tank (42); a driving wheel (4161) is installed at the power output end of the first motor (416); a power wheel (4162) matching the driving wheel (4161) is installed on the side wall of the rotating column (414); and the driving wheel (4161) and the power wheel (4162) are connected by a belt.

5. The sewage treatment system according to claim 1, characterized in that: A limiting seat (441) is arranged at the bottom of the anoxic tank (44), and the limiting seat (441) comprises a first tank body (4411) and a second tank body (4412). The inner diameter of the first tank body (4411) is larger than the inner diameter of the second tank body (4412). The first tank body (4411) is located between the second tank body (4412) and the anaerobic tank (43). A supporting platform (442) is installed between the first tank body (4411) and the anaerobic tank (43). A mud-passing hole (4421) is provided on a side wall of the supporting platform (442), and a mud-extracting hole is provided on the inner wall of the second tank body (4412).

6. The sewage treatment system according to claim 5, characterized in that: A fixing seat (451) is arranged at the bottom of the aerobic pool (45), a collecting groove (4511) is arranged in the middle area of ​​the fixing seat (451), a fixing platform (452) is installed between the fixing seat (451) and the anoxic pool (44), a hole is opened on the side wall of the fixing platform (452), a part of the power column (435) passes through the anoxic pool (44) and extends to the collecting groove (4511), and a fifth spiral blade (453) is arranged between the outer wall of the power column (435) and the collecting groove (4511).

7. A sewage treatment method, comprising a sewage treatment system according to claim 1, characterized in that: The following steps are involved: Step 1: sewage pretreatment; Domestic sewage is collected in a temporary storage tank (1) through a drainage pipe, and then, under the action of a screen decontamination machine (2), larger garbage and debris are transported to a garbage bin, and sewage is transported to a desanding tank (3) for desanding. Step 2, initial settlement; The sewage is transported from the desander (3) to the first sedimentation tank (41) for sedimentation and foam removal. A flocculant is added to the first sedimentation tank (41), and the grease and foam on the surface of the sewage are skimmed off by a decontamination scraper (413). The sewage is left for 3-6 hours, and then the sewage after preliminary sedimentation is transported to the biochemical degradation tank (4); Step three, biochemical sedimentation; After reaching the biochemical degradation tank (4), the sewage first reaches the anaerobic tank (43), anaerobic bacteria are added to the anaerobic tank (43) and air is pumped out, and then the tank is left standing for 5-8 hours, maintaining a temperature of 22-32°C; then, the sewage in the anaerobic tank (43) is transported to the anoxic tank (44), bacteria are added, a low oxygen environment is maintained, and the tank is left standing for 3-5 hours; then, the sewage in the anoxic tank (44) is transported to the aerobic tank (45), aerobic bacteria are added to the aerobic tank (45), and oxygen-rich air is continuously introduced into the aerobic tank (45) and left standing for 4-6 hours; finally, the sewage in the aerobic tank (45) is transported to the second sedimentation tank (42), and the sewage is irradiated with ultraviolet rays at the same time; Step 4, membrane filtration; The sewage is allowed to stand in the second sedimentation tank (42) for 3-5 hours and then pumped into the MBR membrane tank (5). Chlorine gas is introduced into the MBR membrane tank (5). The sewage is filtered through the MBR membrane and becomes recycled water. The recycled water is then sent to the reverse osmosis membrane tank. The reverse osmosis membrane tank separates the recycled water into pure water and high-salt wastewater. The pure water is discharged into the natural environment, and the high-salt wastewater is sent to the high-salt wastewater tank.

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