Dispersed emission source sewage collection-A2O process treatment linkage system and treatment method thereof

Abstract

The invention discloses a decentralized discharge source sewage collection-A2O treatment linkage system and a treatment method. The linkage system comprises a sewage pretreatment and pipe network collection system, an A2O treatment system and a discharge system. By adopting a negative pressure collection technology, the sewage collection problem caused by complex terrain in a sewage collection range is solved, and the sewage collection efficiency is improved; the gas stripping technology, the Venturi technology and the siphon technology are creatively applied to the sewage process, and sewage collection and sewage lifting, muddy water backflow and oxygenation in the A2O process can be achieved only through one self-priming pump; the Venturi jet device directly performs jet aeration on the aerobic tower, so that the dependence on a high-energy-consumption mechanical aeration fan is reduced, and resource waste and material loss are avoided; meanwhile, distribution of water flow and dissolved oxygen in the reaction tank is optimized, natural circulation is formed through the density difference between the aerobic tower and the anoxic tower, additional power is not needed, the energy consumption is reduced, meanwhile, the nitrogen and phosphorus removal process is promoted, and the treatment efficiency is remarkably improved.

Description

Technical Field

[0001] The present invention relates to a decentralized sewage collection system. 2 O process treatment linkage system belongs to the technical field of sewage collection and treatment from dispersed emission sources. Background Art

[0002] In the existing technology, the main method for collecting and treating sewage from dispersed emission sources is to lay a municipal sewage pipe network and use special sewage collection and treatment facilities for treatment. At present, sewage collection is basically carried out by gravity flow, and sewage treatment mainly uses A 2 O process represents secondary biochemical technology, A 2 The O process, namely the Anaerobic-Anoxic-Oxic (anaerobic-anoxic-aerobic) process, is a wastewater treatment technology for simultaneous biological nitrogen and phosphorus removal. The process combines the traditional activated sludge method, biological nitrification and denitrification, and biological phosphorus removal processes, and can effectively remove organic matter, nitrogen and phosphorus from wastewater. However, in the following two situations, first, in areas with complex terrain such as mountainous areas and hills, the cost and construction difficulty of laying gravity flow pipe networks rise sharply; second, for areas with dispersed populations or small amounts of sewage generation, the sewage discharge sources are dispersed, and the total sewage discharge does not exceed 100m³ / d, such as suburban residential areas, schools, and markets that are not connected to municipal sewage pipe networks, as well as concentrated villages, communities, markets, resorts, tourist attractions, farmhouses, corporate factories, and small-scale towns with a population of less than 2,000 in rural areas, it is very uneconomical and unprofitable to lay gravity flow drainage pipe networks in these areas, and the traditional A 2 O technology tends to cause energy waste.

[0003] In the traditional gravity flow system, sewage needs to rely on gravity to flow from high to low. If there is a large elevation difference, multiple lifting pump stations may need to be set up, increasing construction and operation costs. 2 The A process system is relatively passive in responding to different treatment requirements and changes in operating conditions. For example, when a treatment unit needs to be repaired or maintained, the direction and flow of sewage may need to be adjusted. 2 O process treatment technology requires aeration fans, aeration diffusion systems, return pumps, sludge pumps and other equipment. These equipment and facilities have high requirements for materials and manufacturing processes, and need to meet specific operating conditions, resulting in increased equipment procurement costs. 2 There are many problems with O technology, mainly including the following aspects: 1) Problems in sewage collection (existing gravity flow pipe network collection method): a. The traditional sewage treatment process uses cement pipes for household pipes. To ensure that sewage can flow by gravity in the pipe network, the pipes must be laid forward at a certain slope. The trench excavation depth and width are very large, resulting in a large amount of construction. Especially when encountering slopes, rivers, and buildings, the amount of work increases sharply, and the construction cost is high; b. The gravity drainage system can only allow sewage to flow from high places to low places. A lifting pump station needs to be set up in the middle to raise the water level to ensure the normal flow of sewage, resulting in high operation and maintenance costs; c. In order to prevent blockage, the inner diameter of the gravity flow pipe network must be greater than 30 cm. The sewage collection volume is large, but for the sewage discharge volume of 50m 3 For small areas below 1 / d, the scale of construction is too costly and resources are wasted in idleness; d. The sewage flow rate of traditional drainage pipes is too slow, which is prone to siltation and blockage; e: The drainage pipes are not tightly connected, resulting in serious sewage leakage, which reduces the sewage collection rate and seriously pollutes the groundwater.

[0004] 2) Existing sewage treatment (traditional A 2 O process) problems: a.Traditional A 2 The O treatment process requires many pumping stations. For example, the regulating tank needs to be equipped with a lifting pump to greatly increase the sewage elevation; the anaerobic tank needs to be equipped with a stirring device; the aerobic tower needs to be equipped with an aeration fan and a nitrification liquid return pump, and the secondary sedimentation tank needs to be equipped with a sludge return pump. On the one hand, the use of these power equipment leads to high energy consumption in sewage treatment; on the other hand, since these equipment are all easily damaged, they need to be regularly inspected, maintained or replaced, resulting in high manpower and operating costs for sewage treatment. Therefore, it is generally suitable for sewage treatment plants with large sewage treatment scales, but its application is very limited in small-scale sewage treatment plants, especially in sewage treatment in mountainous areas with scattered households.

[0005] b. The quotas of sewage pumps, aeration fans, sludge pumps and other equipment currently available in the market far exceed the actual demand for sewage treatment in small areas. For example, the flow rate of sewage pumps currently available in the market is 3 m 3 / h or more, the air volume of aeration fans is mostly 30m 3 / h or more, most of the sludge pump discharge volume is 10 m 3 / h, while the sewage discharge in most small areas is less than 50 m 3 / d, the sewage pump flow rate required by the sewage treatment facility does not exceed 2 m 3 / h, aeration volume not exceeding 6 m 3 / h, the sludge discharge volume shall not exceed 1m 3 / h. Causing serious energy waste.

[0006] c. Sewage pumps are easily damaged equipment. The more pumps a sewage station uses, the higher its construction cost, the higher the frequency of equipment failure, and the more troublesome the subsequent manual maintenance will be.

[0007] In summary, the existing small-area sewage is mainly collected to the sewage station by gravity flow pipe network, and then the traditional A 2 The O emissions after process treatment obviously have defects such as large cost investment, high energy consumption, and complicated operation and maintenance. Summary of the invention

[0008] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a decentralized discharge source sewage collection - A 2 O process treatment linkage system and its treatment method can solve the problems of large investment, high energy consumption and complex operation and maintenance in the existing technology.

[0009] To achieve the above purpose, the present invention adopts the following technical solutions: A decentralized wastewater collection system 2 O treatment linkage system, characterized by including sewage pretreatment and pipe network collection system, A 2 O treatment system and exhaust system; The sewage pretreatment and pipe network collection system includes a sewage collection pool and a negative pressure pipe network dispersed in a small area. The sewage collection pool is connected to the anaerobic tank through the negative pressure pipe network. The negative pressure pipe network is provided with a controller and a battery valve. The A 2 O treatment system: comprising a sealed anaerobic tank, an aerobic tower and an anoxic tower; the water inlet of the anaerobic tank is connected to the negative pressure pipe network, the bottom of the anaerobic tank is provided with a water outlet pipe connected to the aerobic tower through a first pipe, the first pipe is provided with a self-priming pump and a venturi ejector, the first pipe is also provided with a shunt pipe, the shunt pipe is provided with a regulating valve and a liquid flow meter; one end of the shunt pipe is provided on the first pipe between the self-priming pump and the venturi ejector, and the other end is provided on the top of the anoxic tower and connected to the anoxic tower; the upper and lower parts of the aerobic tower and the anoxic tower are respectively provided with a first circulating water pipe and a second circulating water pipe in communication; a safety valve is provided on the top of the anaerobic tank; The discharge system includes a discharge pipe, a filter screen and a sedimentation tank arranged on the aerobic tower; the sedimentation tank is also connected to the sludge drying filter tank through a pipeline; a sludge storage tank is also arranged at the bottom of the sludge drying filter tank; the sludge storage tank is connected to the first pipeline at the front end of the self-priming pump through a third pipeline.

[0010] Furthermore, the sewage collection tank is a three-grid sewage tank structure; wherein a coarse grid is vertically arranged in the first grid, and a fine grid is vertically arranged in the third grid; the coarse grid and the fine grid respectively divide the first grid and the third grid into two areas, an inlet area and an outlet area, so that impurities are blocked in front of the grid outlet area.

[0011] Furthermore, the sewage collection pools are dispersedly installed in different areas, and PE pipes are shallowly buried; the diameter of the PE pipes is 3-7 cm.

[0012] Furthermore, the sludge drying filter tank is a prefabricated square frame structure, which is placed directly above the regulating tank. The sludge drying filter tank uses materials with different bearing capacities according to the scale of sewage treatment. The bottom plate of the sludge drying filter tank is fully perforated, with a hole diameter of about 0.5 cm and a small hole spacing of about 1 cm. A polypropylene filter cloth is laid on the bottom plate, and the pore size of the filter cloth is approximately between 80 mesh and 300 mesh.

[0013] The present invention also provides a decentralized emission source sewage collection-A 2 The processing method of the process linkage system of O process, using the linkage system, the processing method comprises the following steps: 1) Sewage pretreatment and pipe network collection Sewage enters the sewage collection tank and first ferments and separates solids and liquids in the first two compartments before flowing to the third compartment. Large suspended solids are screened out through the coarse grid of the first compartment and the fine grid of the third compartment in the sewage tank. The sewage level height range in the third compartment, i.e., the upper limit H, is set based on the volume of the third compartment, the daily sewage inflow, and the designed treatment capacity of the sewage treatment system. 上 and the lower limit H 下 The level meter sends the sewage level height data in the sewage pool to the power control switch. When the liquid level in the three-grid pool is higher than H 上 When the liquid level in the three-cell tank is lower than H 下 When the power control switch immediately closes the solenoid valve; 2) Negative pressure suction and anaerobic treatment When the self-priming pump is started, the sewage in the sealed anaerobic tank is pumped out, forming a negative pressure environment in the anaerobic tank and the negative pressure pipe network. Under the action of the atmospheric pressure difference, the sewage from various sewage pools flows into the negative pressure pipe network, and then flows into the negative pressure anaerobic tank, driving the entire system; after the sewage enters the anaerobic tank, the anaerobic tank further mixes the sewage, making full use of the high-efficiency biological filler in the anaerobic tank as a microbial carrier. Under the action of facultative bacteria and anaerobic bacteria, the large molecular organic matter in the sewage is decomposed into small molecular organic matter with better biodegradability through anaerobic fermentation, and the polyphosphate bacteria release orthophosphate and obtain energy under anaerobic conditions.

[0014] 3) Aerobic-anoxic tower combined treatment system Sewage is diverted by a self-priming pump, and part of it flows into the anoxic tower through a diversion pipe. A flow meter and a regulating valve are set in the diversion pipe to adjust the ratio of sewage diversion into the anoxic tower and the aerobic tower. In the anoxic tower, part of the organic matter is used by denitrifying bacteria to promote denitrification and denitrification. The other part of the sewage is transported to the aerobic tower after aeration by a Venturi ejector. In the aerobic tower, the sewage comes from two aspects. One is that the sewage directly enters the aerobic tower after Venturi aeration and oxygenation, and the other is that the sewage in the anoxic tower flows in from the bottom of the connecting pipe by gravity. The organic matter in the sewage is further degraded and removed by microorganisms, and ammonia nitrogen is oxidized to nitrate nitrogen. At the same time, polyphosphate bacteria absorb excessive phosphate under aerobic conditions to synthesize polyphosphate and store it in cells to form phosphorus-rich sludge. The mud-water mixture in the aerobic tower flows upward to the upper end of the aerobic tower under the action of gas lift, and part of it flows back to the anoxic tower for denitrification treatment, and the other part of the mixed liquid flows into the sedimentation tank. 4) Final treatment and discharge The sewage treated by the aerobic tower flows from the aerobic tower to the sedimentation tank. The supernatant in the sedimentation tank is discharged when it meets the requirements. The sludge in the sedimentation tank is discharged by gravity. Part of the flow flows directly into the sludge storage tank, and the other part flows to the sludge drying and filtration tank for dehydration.

[0015] Furthermore, a liquid level gauge is built into the sludge storage tank, and a pipe with an electromagnetic valve is set to connect with the pipe in front of the self-priming pump; the sewage level height range in the sludge storage tank, i.e., the upper limit H, is set based on the volume of the sludge storage tank, the total amount of mud and water flowing in every day, and the designed treatment capacity of the sewage treatment system. 上 and the lower limit H 下 The level meter sends the sewage level height data in the sludge storage tank to the power control switch. When the liquid level in the tank is higher than H 上 When the power control switch opens the solenoid valve, the mud-water mixture in the pool is sucked into the pipeline by the self-priming pump and transported to the aerobic tower and the anoxic tower for further treatment; when the liquid level in the pool is lower than H 下 When the power control switch closes the solenoid valve immediately.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention creatively adopts a specially designed negative pressure collection technology. By using a self-priming pump to suck the sewage from the anaerobic tank, a negative pressure environment is formed in the sealed anaerobic tank. The anaerobic tank is connected to the sewage collection network. Under the action of atmospheric pressure, the sewage from each emission source is finally collected into the sealed anaerobic tank through the negative pressure collection network. This method solves the sewage collection problem caused by the complex terrain within the sewage collection range, effectively avoids the problems of unstable flow and water collection difficulties caused by terrain changes in the traditional collection system, and improves the sewage collection efficiency; at the same time, PE pipes are used with a diameter of 3 to 7 cm, a shallow burial depth, and low construction difficulty, which greatly reduces the construction cost and excavation volume, and effectively reduces leakage and is not affected by the terrain.

[0017] In terms of sewage collection, the present invention uses a self-priming pump to create a negative pressure environment in the sealed anaerobic tank to collect sewage under negative pressure. This negative pressure suction can reduce dependence on external auxiliary equipment, reduce energy consumption, save manpower and time, and improve the efficiency of the sewage collection system. Furthermore, by adopting negative pressure collection technology, the negative pressure pipe network collection system can overcome terrain obstacles and pump sewage from various collection points to the treatment facility through pressure difference, ensuring that sewage can be collected efficiently. Even in low-lying areas or areas with high groundwater levels, negative pressure pipe network collection can effectively avoid sewage backflow and overflow problems, ensuring the stable operation of the collection system. In addition, the power equipment only requires a self-priming pump, the process flow is clear, and the equipment operation is simple and easy to understand. Stable operation can be ensured by regular maintenance and inspection of the equipment.

[0018] The present invention creatively applies air lift technology, Venturi technology and siphon technology to the sewage process, and finally only needs one self-priming pump to realize the collection and treatment of sewage with exquisite structural design. 2 O process. The negative pressure environment formed in the anaerobic tank by the self-priming pump sucking the sewage in the sealed anaerobic tank allows the sewage to circulate, reducing the use of various types of pumps and saving energy consumption; the Venturi ejector directly aerates the sewage, reducing the dependence on high-energy mechanical aeration fans, avoiding resource waste and material loss; at the same time, the water flow and dissolved oxygen distribution in the reaction pool are optimized, and the density difference between the gas-water mixture between the aerobic tower and the anoxic tower forms an air lift force through the special structure of the aerobic-anoxic combined tower, so that the sewage in the aerobic tower and the anoxic tower can be internally circulated without the need for additional power, reducing energy consumption while promoting the denitrification and phosphorus removal process, so that the treatment efficiency is significantly improved.

[0019] Among them, part of the sewage, under the action of the thrust of the self-priming pump, passes through the Venturi ejector and uses the Venturi device jet aeration to supply oxygen autonomously. This part of the sewage after aeration and oxygenation flows autonomously into the aerobic tower to ensure the smooth progress of the nitrification reaction in the aerobic tower. Another part of the sewage is transported to the anoxic tower by the self-priming pump to provide sufficient substrate and carbon source for the denitrifying bacteria in the anoxic tower, promoting the progress of the denitrification reaction, thereby improving the denitrification efficiency, which can better solve the above pain points. Gravity self-flow is used in the sludge treatment method. The sludge in the sedimentation tank uses gravity to flow partly to the sludge storage tank, and partly to the sludge drying and filtration tank for mud and water separation.

[0020] 3. The present invention avoids the energy waste of "a big horse pulling a small cart". Through a specially designed sewage collection method, it reduces pipeline consumables and pipeline construction workload, greatly reduces the investment in construction projects, and only requires a self-priming pump for power equipment, reducing costs and energy consumption. It can also "replenish carbon and oxygen" by itself, and is truly suitable for small-scale sewage treatment in multiple scenarios, improving residents' environmental awareness and promoting the development of sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The invention is a decentralized emission source sewage collection-A 2 O Schematic diagram of the process linkage system structure.

[0022] Figure 2 It is a three-compartment sewage collection tank in the present invention.

[0023] Figure 3 It is a process diagram of the present invention.

[0024] In the figure, 1 is a three-grid sewage pool, 2 is an anaerobic tank, 3 is an aerobic tower, 4 is an anoxic tower, 5 is a sedimentation tank, 6 is a sludge drying and filtering organization, 7 is a sludge storage tank, 8 is a controller, 9 is a solenoid valve, 10 is a safety valve, 11 is a self-priming pump, 12 is a solenoid valve, 13 is a venturi ejector, 14 is a liquid flow meter, 15 is a gas flow meter, 16 is a sludge controller, 17 is a sludge return control valve, 18 is a sewage negative pressure collection network, 19 is a diversion pipe 1, 20 is a diversion pipe 2, 21 is an anoxic tower sewage to aerobic tower gravity pipe, 22 is an aerobic tower sewage to anoxic tower return pipe, 23 is a treated sewage outflow pipe, 24 is a treatment standard supernatant discharge pipe, 25 is a sludge gravity flow pipe, and 26 is a sludge return pipe. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is clearly and completely described below in conjunction with specific embodiments and drawings. Obviously, the embodiments are only representative of embodiments of the present invention and are not limited to the described embodiments. Therefore, the following detailed description of the embodiments provided in the drawings is not intended to limit the scope of the invention claimed for protection. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. The terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the figures, or the positions or positional relationships in which the invented product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] 1. A decentralized wastewater collection system 2 OProcess processing linkage system like Figure 1 As shown, the present invention provides a decentralized emission source sewage collection-A 2 O treatment linkage system, including: sewage pretreatment and pipe network collection system, A 2 O treatment system and discharge system; the structure of each system is as follows: 1.1 Sewage pretreatment and pipe network collection system: mainly includes sewage collection pools 1 dispersedly distributed in a small area (there are many dispersed sewage discharge sources, generally the sewage discharged by each sewage discharge source is collected into a corresponding sewage pool, and the discharge sources that are close to each other can share a sewage pool), and a sewage negative pressure collection pipe network 18. The sewage collection pool 1 is connected to the anaerobic tank 2 through the sewage negative pressure collection pipe network 18, and the sewage negative pressure collection pipe network 18 is provided with a controller 8 and a first battery valve 9.

[0028] The sewage collection tank 1 of this embodiment is a three-compartment sewage tank structure to form a fermentation area and a solid-liquid separation area, to prevent large particles from entering the negative pressure pipe and causing pipe network blockage, and to minimize the particles in the sewage flowing into the anaerobic tank 2. Figure 2 , two partitions are vertically arranged in the sewage collection tank 1 to form three grid areas, and water pipes 1.1 are arranged between the areas for communication. Among them, a coarse grid 1.2 is vertically arranged in the first grid, and a fine grid 1.3 is vertically arranged in the third grid; the coarse grid 1.2 and the fine grid 1.3 respectively divide the first grid and the third grid into two areas, the water inlet area and the water outlet area, so that impurities are blocked in front of the grid outlet area. In the figure, 1.4 is the water inlet pipe, and 1.5 is the water outlet pipe.

[0029] 1.2 New Type A 2O treatment system: including an anaerobic tank 2, an aerobic tower 3 and an anoxic tower 4; the anaerobic tank 2 is kept sealed as much as possible, and its water inlet is connected to the sewage negative pressure collection pipe network 18. A first shunt pipe 19 is provided at the bottom of the anaerobic tank 2 to be connected to the aerobic tower 3. A self-priming pump 11 and a venturi ejector 13 are provided on the first shunt pipe 19. A branch is also provided on the first shunt pipe 19, which is a second shunt pipe 20. A regulating valve 12 and a liquid flow meter 14 are provided on the second shunt pipe 20; one end of the second shunt pipe 20 is provided on the first shunt pipe 19 between the self-priming pump 11 and the venturi ejector 13, and the other end is provided on the top of the anoxic tower 4 to be connected to the anoxic tower 4; an anoxic tower sewage to aerobic tower gravity pipe 21 is provided at the lower part of the aerobic tower 3 and the anoxic tower 4, and an aerobic tower sewage to anoxic tower reflux pipe 22 is provided at the upper part of the aerobic tower 3 and the anoxic tower 4. A safety valve 10 is provided on the top of the anaerobic tank 2. When the pressure in the anaerobic tank exceeds the upper limit and there is a safety risk, the safety valve automatically opens to discharge part of the fermentation gas. Biological fillers are provided in the anaerobic tank 3, the aerobic tower 6 and the anoxic tower 7 to provide a carrier for the growth and reproduction of microorganisms.

[0030] 1.3 Discharge system: including the outlet pipe 23 (the outlet pipe for sewage after aerobic tower treatment) arranged on the aerobic tower 3, the supernatant discharge pipe 24 of the sedimentation tank, the sludge gravity flow discharge pipe 25 and the sludge return pipe 26; the discharge pipe 23 is connected to the sedimentation tank 5, and the sludge gravity flow pipe 25 is connected to the sludge drying filter tank 6 and the sludge storage tank 7 in sequence. The sludge storage tank 7 is connected to the first diversion pipe 19 at the front end of the self-priming pump 9 through the sludge return pipe 26. Among them, the present invention designs a sludge drying filter tank 6 in view of the characteristics of small sewage treatment volume and small sludge discharge volume in a small area. The sludge drying filter tank 6 is in the form of a square frame prefabricated structure, which is placed directly above the sludge storage tank 7. The sludge drying filter tank 6 selects materials with different bearing capacities according to the scale of sewage treatment. The bottom plate of the sludge drying filter tank is fully perforated, with a hole diameter of about 0.5 cm and a small hole spacing of about 1 cm. A polypropylene filter cloth (or other filter cloths with good corrosion resistance, acid and alkali resistance, wear resistance, stability, high temperature resistance and air permeability) is laid on the bottom plate. The pore size of the filter cloth is between 80 mesh and 300 mesh, and the specific pore size is determined according to the characteristics of the sludge. 2. The present invention disperses the wastewater collection source - A 2 OThe processing flow of the process linkage system includes: 2.1 Sewage pretreatment and collection: Sewage from various dispersed emission sources within the sewage collection range flows by gravity into a three-grid sewage pool, undergoes anaerobic fermentation, solid-liquid separation and coarse and fine two-stage screen filtration in the first two grids of the sewage pool, and finally flows to the third grid. When the sewage in the third grid pool reaches the specified upper limit of height, the liquid level meter feeds back the sewage height to the controller, and the controller starts the solenoid valve on the outlet pipe to open, so that the pretreated sewage from the three-grid pool passes through the outlet pipe and the negative pressure collection pipe to the closed anaerobic tank; in this process, when the self-priming pump sucks the sewage in the anaerobic tank, negative pressure is formed in the anaerobic tank and the collection network. Under the action of atmospheric pressure, the sewage flows from the three-grid sewage pool into the negative pressure network, and finally flows into the negative pressure anaerobic tank and enters the next treatment procedure, thus avoiding the construction of a lifting pump during the sewage collection process.

[0031] 2.2 New Type A 2 O process: After the sewage is treated by an anaerobic tank, it is pumped out to the next treatment system by a self-priming pump at regular intervals. After being pumped out by the self-priming pump, the sewage is divided into two parts. One part flows into the anoxic tower to provide a carbon source for the denitrification and denitrification of microorganisms in the tower, and the other part flows into the aerobic tower through the Venturi, where aerobic and nitrification reactions occur. When the sewage passes through the Venturi, air is sucked into the throat of the Venturi, forming an air-water mixture with the sewage, and finally transported to the aerobic tower. In this way, the sewage is transported from the anaerobic tank to the aerobic tower, and the purpose of sewage jet aeration and oxygenation is achieved.

[0032] The present invention designs a special structure of an aerobic tower and an anoxic tower connected structure. In the aerobic tower, the air-water mixture formed by the venturi has the power to move upward under the action of the gas lift buoyancy. At the same time, because the density of the air-water mixture in the aerobic tower is lower than the density of the sewage in the anoxic tower, the liquid pressure in the aerobic tower is lower than that in the anoxic tower, so that the sewage in the anoxic tower flows into the aerobic tower through the connecting pipe at the bottom, and further promotes the air-water mixture in the aerobic tower to move upward (this process is also called gas lift). When the air-water mixture in the aerobic tower flows up to the top of the aerobic tower under the gas lift (at this time, most of the air in the sewage has been released and escaped from the sewage, and the density is close to that of the sewage), a part of the sewage passes through the bottom of the aerobic tower. The connecting pipe flows back into the anoxic tower for denitrification and denitrification. A valve is set on the connecting pipe to control the reflux rate (reflux ratio). The sewage flowing back to the anoxic tower then flows down to the bottom of the anoxic tower and then flows into the aerobic tower through the bottom connecting pipe, thus completing the reflux cycle of the nitrification liquid in the aerobic tower. Another part of the sewage in the aerobic tower flows into the sedimentation tank through the top of the tower for mud and water separation. The supernatant in the sedimentation tank is discharged when it meets the requirements. The sludge in the mud hopper of the sedimentation tank uses gravity to flow directly into the sludge storage tank, and the other part flows to the specially designed sludge drying filter tank for dehydration. The water in the sludge infiltrates into the sludge storage tank through the filter membrane at the bottom of the drying filter tank, and the sludge is retained in the sludge drying filter tank. A pipeline is set to connect the sludge storage tank with the water inlet pipe of the self-priming pump. The sludge in the sludge storage tank is sucked into the pipeline regularly by the self-priming pump, and finally flows back to the aerobic tower and the anoxic tower for treatment again.

[0033] 2.3 Wastewater discharge and treatment The wastewater treated in the aerobic tower flows from the aerobic tower to the sedimentation tank. The supernatant on the top of the sedimentation tank meets the requirements and is discharged. The sludge in the sedimentation tank is discharged by gravity. Part of the flow flows directly into the sludge storage tank (to be treated again by the aerobic tower and anoxic tower under the self-priming pump), and the other part flows to the sludge drying and filtration tank for dehydration.

[0034] In summary, the present invention only needs to use a self-priming pump power facility, and then cooperate with the anaerobic tank, the venturi ejector and the special structure of the aerobic tower-anoxic tower joint structure to form a new type of A 2 O sewage treatment technology can realize sewage lifting, aeration, sludge return, digestion liquid return and sludge discharge, thus avoiding the traditional A 2The use of high-energy-consuming and easily damaged power equipment such as aeration fans, sewage lifting pumps, sludge return pumps, and nitrification liquid return pumps in the O technology not only saves energy consumption, but also effectively treats various pollutants in sewage, and the effluent water quality is stable, meeting national or local emission standards; it improves the surrounding environment and reduces sewage treatment costs on the basis of ensuring that the water quality meets the standards; and it has the characteristics of high efficiency and energy saving. It is suitable for the collection and treatment of sewage (similar to domestic sewage) in areas with complex terrain such as mountainous areas and hills (the laying cost and construction difficulty of gravity flow pipe networks in these areas have risen sharply), as well as suburban residential areas, schools, and markets that are not connected to municipal sewage pipe networks, as well as concentrated villages, communities, markets, resorts, tourist attractions, farmhouses, corporate factories, and small-scale towns with a population of less than 2,000 in rural areas.

[0035] III. Sewage collection from dispersed emission sources of the present invention - A 2 O Processing method of process linkage system See also Figure 3 As shown, the processing flow and processing method include the following steps: 3.1 Sewage pretreatment and pipe network collection In the small area where the sewage discharge sources are scattered, each discharge source is equipped with a three-grid sewage pool for advanced sewage pretreatment. The sewage is first fermented and solid-liquid separated in the first two grids before flowing to the third grid. The larger suspended matter is screened out through the coarse grid of the first grid and the fine grid of the third grid in the sewage pool. The third grid is equipped with a level meter and an outlet pipe with a solenoid valve. The sewage level height range in the third grid pool, i.e. the upper limit H, is set based on the volume of the third grid, the daily sewage inflow, and the designed treatment capacity of the sewage treatment system. 上 and the lower limit H 下 The level meter sends the sewage level height data in the sewage pool to the power control switch. When the liquid level in the three-grid pool is higher than H 上 When the liquid level in the three-cell tank is lower than H 下 When the power control switch closes the solenoid valve immediately.

[0036] Negative pressure suction and anaerobic treatment When the self-priming pump is started, the sewage in the anaerobic tank is pumped out, forming a negative pressure environment on the upper part of the anaerobic tank and in the negative pressure pipe network. Under the action of the atmospheric pressure difference, the sewage in various sewage pools flows into the negative pressure collection pipe network, and then flows into the negative pressure anaerobic tank, driving the entire system. In this process, the self-priming pump is reasonably set through the automatic controller. The self-priming pump not only plays a key role in pumping sewage to create negative pressure, but also can achieve the purpose of adjusting the running time, so that the sewage in each three-grid pool is collected into the anaerobic tank according to the set time (to ensure that the sewage in the sewage pool will not overflow), and at the same time, the sewage in the anaerobic tank is reasonably and evenly transported to the aerobic tower and the anoxic tower. The running time is reasonably and evenly set according to the discharge volume and system processing capacity, and it provides power for the flow of sewage in the entire system.

[0037] After the sewage enters the anaerobic tank, the anaerobic tank further mixes the sewage, making full use of the efficient biological filler in the anaerobic tank as a microbial carrier. Under the action of facultative bacteria and anaerobic bacteria, the macromolecular organic matter in the sewage is decomposed into small molecular organic matter with better biodegradability through anaerobic fermentation, and the polyphosphate bacteria release orthophosphate and obtain energy under anaerobic conditions. At this stage, due to the release of orthophosphate by polyphosphate bacteria, the concentration of phosphorus in the sewage increases, and the organic matter in the sewage is decomposed and absorbed by microorganisms, which is conducive to further oxidation and decomposition in the subsequent biological treatment tank. A safety valve is set at the top of the anaerobic tank. When there is too much fermentation gas in the anaerobic tank, causing the air pressure in the anaerobic tank to exceed the set upper limit value, and there is a safety risk, the safety valve automatically opens to discharge part of the fermentation gas. 3.3 Aerobic-anoxic tower combined treatment system The sewage is diverted by the self-priming pump, and part of it flows into the anoxic tower through the diversion pipeline. A flow meter and a regulating valve are set in the diversion pipeline. The regulating valve is used to control the proportion of sewage diversion entering the anoxic tower and the aerobic tower. The sewage entering the anoxic tower contains a high level of organic matter, which can provide organic matter as a carbon source for denitrifying bacteria, reducing nitrate nitrogen and nitrite nitrogen into nitrogen gas. At the same time, the anoxic tower removes part of the BOD.

[0038] The other part of the sewage is aerated by the Venturi ejector and then transported to the aerobic tower. Here, the Venturi mainly plays the role of jet aeration, thereby avoiding the use of high-energy consumption equipment aeration fans, and plays a key role in aeration and oxygenation of the aerobic tower and the rise of sewage gas lift. In addition, a gas flow meter is set on the Venturi air inlet pipe to adjust the aeration volume in real time. In the aerobic tower, sewage comes from two aspects. One part is the sewage that enters the aerobic tower directly after Venturi aeration and oxygenation, and the other is the sewage in the anoxic tower from the bottom of the connecting pipe. The organic matter in the sewage in the aerobic tower is further removed by microbial degradation, and ammonia nitrogen is oxidized to nitrate nitrogen. At the same time, polyphosphate bacteria absorb excessive phosphate under aerobic conditions to synthesize polyphosphate, and store it in the cells to form phosphorus-containing sludge. The BOD5 in the sewage in the aerobic tower is further reduced, and the phosphate concentration in the sewage decreases a lot with the excessive intake of polyphosphate bacteria. Then the mud-water mixture in the aerobic tower flows upward under the action of gas lift, part of it flows back to the anoxic tower for denitrification treatment, and the rest of the mixture flows into the sedimentation tank.

[0039] The characteristics of this stage are as follows: part of the sewage in the anaerobic tank is directly transported to the anoxic tower by a self-priming pump, and the organic matter in the sewage supplements the carbon source for the denitrification and denitrification of the denitrifying bacteria in the anoxic tower; the biological denitrification of the anoxic tower consumes part of the organic matter, reducing the organic load of the aerobic tower; the alkalinity generated by the denitrification reaction of the sewage in the anoxic tower can also supplement the alkalinity for the nitrification reaction in the aerobic tower. In the aerobic tower, aerobic microorganisms further decompose the residual organic matter in the sewage, so that the effluent water quality can be improved. The lower and upper parts of the aerobic tower are reasonably set with connecting pipes to connect the two. Under the action of gas lift, the circulation reflux between the sewage in the aerobic tower and the anoxic tower can be realized, thereby improving the efficiency of denitrification and denitrification. 3.4 Final treatment and discharge The sewage treated by the aerobic tower flows from the aerobic tower to the sedimentation tank. The supernatant in the sedimentation tank meets the requirements and is discharged. The sludge in the sedimentation tank is discharged by gravity and divided. One part flows directly into the sludge storage tank (to be pumped to the aerobic-anoxic tower for treatment by the self-priming pump), and the other part flows to the sludge drying and filtration tank for dehydration.

[0040] Most of the water in the sludge discharged into the sludge drying filter pool penetrates through the filter cloth under the action of gravity and flows into the sludge storage tank. The sludge matrix trapped in the drying filter pool is further evaporated and dehydrated under the action of natural weathering. The volume of the sludge drying filter pool shall at least meet the sludge storage needs of the sedimentation tank for half a month. The size of the sludge drying filter pool is designed according to the size of the sludge storage tank. It must be placed directly above the sludge storage tank, and the requirements that the infiltrated sewage can all flow into the sludge storage tank. A rainproof roof is set directly above the sludge drying filter pool, and the distance between the roof and the filter tank must meet the requirements of smooth ventilation and rain protection. As the sludge in the sludge drying filter pool accumulates more and more, it is necessary to manually clean it regularly (about once every two weeks), and rinse the filter cloth and bottom plate at the bottom to prevent blockage. Part of the sludge discharged from the sedimentation tank flows directly into the sludge storage tank, and the other part is discharged into the sludge drying filter pool for dehydration. The water in the sludge seeps through the filter cloth and flows into the sludge storage tank. A level gauge is built into the sludge tank, and a pipe with a solenoid valve is set to connect it to the pipe in front of the self-priming pump. The sewage level height range in the sludge tank, i.e. the upper limit H, is set based on the volume of the sludge tank, the total amount of sludge water flowing in every day, and the designed treatment capacity of the sewage treatment system. 上 and the lower limit H 下 The level meter sends the sewage level height data in the sludge storage tank to the power control switch. When the liquid level in the tank is higher than H 上 When the power control switch opens the solenoid valve, the mud-water mixture in the pool is sucked into the pipeline by the self-priming pump and transported to the aerobic tower and the anoxic tower for further treatment; when the liquid level in the pool is lower than H 下 When the power control switch closes the solenoid valve immediately.

[0041] Reasonable selection of self-priming pump models so that its flow rate meets the needs of sewage collection and treatment, and the suction head meets the elevation requirements, can allow the sewage in the sludge storage tank and the sewage in the anaerobic tank to be sucked into the self-priming pump.

[0042] 4. Compared with traditional technologies, the present invention has achieved unexpected technical effects in terms of operating energy consumption, construction cost, operating and maintenance cost, and energy recovery. Mainly including: 4.1 Operation energy consumption: Traditional A 2 O system usually consumes a large amount of energy due to its reliance on aeration fans, sludge return pumps, digestate return pumps, and sewage lifting pumps. Compared with the traditional system, the system of the present invention optimizes the aeration and circulation methods, especially through the addition of Venturi, which reduces the energy consumption required for each cubic meter of sewage treatment, reducing energy consumption by 40%-50% compared with the traditional system.

[0043] Consumables and construction costs: Traditional gravity flow drainage pipe networks require large-scale infrastructure construction (such as concrete structures, steel equipment, etc.), resulting in high construction costs. In contrast, the system of the present invention adopts a modular design, and the equipment is more concise, especially the negative pressure collection pipe only needs about 3 to 7 cm of PE pipe to meet the sewage collection requirements, reducing the manpower and material consumption of pipe network construction.

[0044] Operation and maintenance costs: Traditional A 2 The O system uses a large number of pumps of various forms, and its operation and maintenance rely on manual and equipment repairs. The equipment structure is complex and the failure rate is high, resulting in high maintenance costs. Usually, 10%-15% of the facility construction cost is paid as maintenance fees each year. Compared with the traditional system, the system of the present invention only needs one self-priming pump power equipment to meet all the power requirements of the sewage station, which greatly reduces energy consumption and operation and maintenance costs. The maintenance cost of the new system is 45%-60% lower than that of the traditional system, and because the equipment is more reliable and the failure rate is lower, the system has a longer operation cycle.

[0045] Scope of application: (1) Collection and treatment of wastewater from dispersed emission sources in areas with large terrain fluctuations such as mountainous areas or hills; (2) Rural residential areas: especially the collection and treatment of domestic sewage or similar domestic sewage in rural areas without sewage collection and sewerage networks, such as the collection and treatment of domestic sewage or similar domestic sewage in rural villages, concentrated villages, communities and markets; (3) Rural resorts and hotels: Tourist attractions, resorts, small and medium-sized hotels and other places located in rural areas need to ensure that the environment is not polluted and meets tourism environmental protection requirements; (4) Enterprises and factories: domestic sewage and low-concentration organic production wastewater generated by enterprises and factories; (5) Agriculture and breeding: Applicable to livestock and poultry breeding wastewater treatment, as well as wastewater treatment and recycling in farms and orchards; (6) Suburban areas or small towns: Collection and treatment of domestic sewage in suburban residential areas or small towns that are not connected to the municipal sewage network.

[0046] V. Technical description of promotion prospects 5.1 Efficient treatment: Through the screening of coarse and fine grids, as well as the coordinated treatment of anaerobic tanks, aerobic towers and anoxic towers, suspended solids, organic matter and nutrients such as nitrogen and phosphorus in sewage can be effectively removed to ensure that the effluent quality meets the standards. 5.2 Energy saving and emission reduction: The process uses a self-priming pump to create a negative pressure environment to pull the sewage flow, reducing the energy consumption in traditional sewage treatment processes. 5.3 Intelligent management: With the development of the Internet of Things and artificial intelligence technologies, this process can incorporate more intelligent elements. For example, by installing sensors to monitor key parameters such as water quality and water volume in real time, big data analysis and artificial intelligence algorithms can be used to accurately predict and optimize the sewage treatment process to improve treatment efficiency. 5.4 Flexible adaptation: The anoxic-aerobic conjoined tower used in this process can be flexibly adjusted according to actual water quality and treatment needs. At the same time, for the differences in sewage production and composition in different regions, it can also be adapted by centrally installing storage pools and adjusting the treatment process. 5.5 Resource recycling: The treated sewage can meet the discharge standards and can even be directly used for agricultural irrigation, industrial cooling and other purposes, realizing the recycling of water resources. In addition, nutrients such as nitrogen and phosphorus recovered from sewage can also be used to make fertilizers, further improving the efficiency of resource utilization.

[0047] 5.6 is particularly suitable for mountainous and hilly areas. The laying of gravity flow pipes in mountainous and hilly areas requires a huge amount of construction. The negative pressure pipe network sewage pipe network of the present invention is laid uphill or downhill along the surface, is not affected by the terrain, has a shallow burial depth, and is easy to construct. The collection pipe network only needs about 3 to 7 cm of PE pipe, which significantly reduces the pipe network consumables and costs, and the advantages are extremely obvious.

[0048] According to the preliminary experimental results and the comparison with the existing sewage collection and treatment technology, the sewage collection pipe network construction cost of the present invention can be reduced by more than 50%, the sewage treatment facility construction cost can be reduced by more than 20%, the treatment energy consumption can be reduced by more than 35%, and the effluent water quality can reach the Class B standard of the "Pollutant Discharge Standard for Urban Sewage Treatment Plants" (GB 18918-2002) or above. In addition to the above short-term economic benefits, this project can also drive multiple economic benefits by relying on the sewage treatment of a small area, such as saving water resources, reducing water treatment costs, improving resource recovery rates and reducing infrastructure investment.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A decentralized wastewater collection system 2 O processing linkage system, characterized in that, Including sewage pretreatment and pipe network collection system, A 2 O treatment system and exhaust system; The sewage pretreatment and pipe network collection system includes a sewage collection pool and a negative pressure pipe network dispersed in a small area. The sewage collection pool is connected to a sealed anaerobic tank through a negative pressure pipe network. A controller and a solenoid valve are provided on the negative pressure pipe network. The A 2 O treatment system: comprising a sealed anaerobic tank, an aerobic tower and an anoxic tower; the water inlet of the anaerobic tank is connected to the negative pressure pipe network, the bottom of the anaerobic tank is provided with a water outlet pipe connected to the aerobic-anoxic combined tower through a first pipe, the first pipe is provided with a self-priming pump and a venturi ejector, the first pipe is also provided with a shunt pipe, the shunt pipe is provided with a flow regulating valve and a liquid flow meter; one end of the shunt pipe is provided on the first pipe between the self-priming pump and the venturi ejector, and the other end is provided on the top of the anoxic tower and connected to the anoxic tower; the upper and lower parts of the aerobic tower and the anoxic tower are respectively provided with a first circulating water pipe and a second circulating water pipe that are connected, so that the upper and lower ends of the aerobic tower and the anoxic tower are connected, so that the sewage in the two towers can be circulated; a safety valve is provided on the top of the anaerobic tank, and when the air pressure in the tank exceeds the safety setting limit, the safety valve can automatically open to release part of the gas; The discharge system includes a discharge pipe, a filter screen and a sedimentation tank arranged on the aerobic tower; the sedimentation tank is also connected to the sludge drying filter tank through a pipeline; a sludge storage tank is also arranged at the bottom of the sludge drying filter tank; the sludge storage tank is connected to the first pipeline at the front end of the self-priming pump through a third pipeline.

2. According to claim 1, the decentralized source sewage collection-A 2 O processing linkage system, characterized by: The sewage collection tank is a three-grid sewage tank structure; wherein a coarse grid is vertically arranged in the first grid, and a fine grid is vertically arranged in the third grid; the coarse grid and the fine grid respectively divide the first grid and the third grid into two areas, an inlet area and an outlet area, so that impurities are blocked in front of the grid outlet area.

3. The method for collecting wastewater from dispersed emission sources according to claim 1 2 O processing linkage system, characterized by: The sewage collection pools are dispersedly installed in different areas, and PE pipes are shallowly buried; the diameter of the PE pipes is 3-7 cm.

4. The method for collecting wastewater from dispersed emission sources according to claim 1 - A 2 O processing linkage system, characterized by: The sludge drying filter tank is a prefabricated square frame structure, which is placed directly above the sludge storage tank. The sludge drying filter tank uses materials with different bearing capacities according to the scale of sewage treatment. The bottom plate of the sludge drying filter tank is fully perforated, with a hole diameter of about 0.5 cm and a small hole spacing of about 1 cm. A polypropylene filter cloth is laid on the bottom plate, and the pore size of the filter cloth is between about 80 mesh and 300 mesh. The specific pore size is determined according to the characteristics of the sludge.

5. A decentralized wastewater collection system 2 O The processing method of the process linkage system is characterized by: The linkage system according to claim 1, 2, 3 or 4 is used, and the processing method thereof comprises the following steps: 1) Sewage pretreatment and pipe network collection Sewage from each sewage discharge source flows into the sewage collection tank by gravity, and first flows to the third tank after fermentation and solid-liquid separation in the first two compartments, and is connected to the negative pressure pipe network through the outlet pipe; the sewage in the sewage collection tank is filtered through the coarse grid of the first compartment and the fine grid of the third compartment to screen out larger suspended solids; according to the volume of the third compartment, the daily sewage water volume and the designed treatment capacity of the sewage treatment system, the sewage level height range in the third compartment, i.e. the upper limit H, is set comprehensively. 上 and the lower limit H 下 The level meter sends the sewage level height data in the sewage pool to the power control switch. When the liquid level in the three-grid pool is higher than H 上 When the liquid level in the three-cell tank is lower than H 下 When the power control switch immediately closes the solenoid valve; 2) Negative pressure suction and anaerobic treatment When the self-priming pump is started, the sewage in the sealed anaerobic tank is pumped out, forming a negative pressure environment on the upper part of the anaerobic tank and the sewage collection network. Under the action of the atmospheric pressure difference, the sewage from various sewage pools flows into the negative pressure network, and then flows into the negative pressure anaerobic tank, driving the entire system; after the sewage enters the anaerobic tank, the anaerobic tank further mixes the sewage, making full use of the high-efficiency biological filler in the anaerobic tank as a microbial carrier. Under the action of facultative bacteria and anaerobic bacteria, the macromolecular organic matter in the sewage is decomposed into small molecular organic matter with better biodegradability through anaerobic fermentation, and the polyphosphate bacteria release orthophosphate and obtain energy under anaerobic conditions; 3) Aerobic-anoxic tower combined treatment system The sewage is diverted after being output by the self-priming pump, and part of it flows into the anoxic tower through the diversion pipeline. A flow meter and a regulating valve are set in the diversion pipeline to adjust the proportion of sewage diversion into the anoxic tower and the aerobic tower; in the anoxic tower, part of the organic matter is used by denitrifying bacteria to promote denitrification; the other part of the sewage after diversion is aerated by the Venturi ejector and then transported to the aerobic tower; the sewage in the aerobic tower comes from two aspects, one is the sewage that is aerated and oxygenated by the Venturi directly into the aerobic tower In the tower, secondly, the sewage in the anoxic tower flows into the bottom of the aerobic tower from the bottom connecting pipe. The organic matter in the sewage in the aerobic tower is further degraded and removed by microorganisms, and the ammonia nitrogen is oxidized to nitrate nitrogen. At the same time, polyphosphate bacteria absorb excessive phosphate under aerobic conditions to synthesize polyphosphate and store it in cells to form phosphorus-rich sludge; then the mud-water mixture in the aerobic tower flows upward under the action of gas lift, a part of it is circulated back to the anoxic tower for denitrification treatment, and the other part of the mixture flows into the sedimentation tank from the upper part of the aerobic tower; 4) Final treatment and discharge: The sewage treated by the aerobic tower flows from the aerobic tower to the sedimentation tank. The supernatant in the sedimentation tank meets the treatment requirements and is discharged. The sludge in the sedimentation tank is discharged by gravity. Part of the flow flows directly into the sludge storage tank, and the other part flows to the sludge drying filter tank for dehydration. The water in the sewage seeps through the filter net and flows into the sludge storage tank. The dehydrated sludge is cleaned regularly.

6. The method for collecting wastewater from dispersed emission sources according to claim 5 - A 2 O treatment method, characterized in that: A liquid level gauge is installed in the sludge storage tank, and a pipe with a solenoid valve is connected to the pipe in front of the self-priming pump; the sewage level height range in the sludge storage tank, i.e. the upper limit H, is set based on the volume of the sludge storage tank, the total amount of mud and water flowing in every day, and the designed treatment capacity of the sewage treatment system. 上 and the lower limit H 下 The level meter sends the sewage level height data in the sludge storage tank to the power control switch. When the liquid level in the tank is higher than H 上 When the power control switch opens the solenoid valve, the mud-water mixture in the pool is sucked into the pipeline by the self-priming pump and transported to the aerobic tower and the anoxic tower for further treatment; when the liquid level in the pool is lower than H 下 When the power control switch closes the solenoid valve immediately.

Images