Granular carbon magnetic coagulation sedimentation tank

Abstract

The present invention provides a granular carbon magnetic coagulation sedimentation tank, which relates to the technical field of sewage treatment. The tank comprises a reaction zone, a carbon adsorption zone, and a sedimentation zone. The reaction zone is provided with magnetic powder for adsorbing suspended matter in sewage. The sedimentation zone is located between the reaction zone and the carbon adsorption zone and includes a buffer zone and a sludge sedimentation zone. The sludge sedimentation zone is connected to magnetic mud recovery equipment. The carbon adsorption zone is provided with a water distribution channel, a water inlet main, a water distributor air lift central pipe, and a carbon backwasher. The carbon adsorption zone is provided with granular activated carbon, which is coal-based granular carbon and is used to adsorb organic pollutants in sewage. The carbon adsorption zone is also provided with an air lift carbon absorption and delivery port, which is located at the upper end of the carbon backwasher. The saturated carbon in the tank body is lifted and transported to the outside of the tank body by compressed air. After dehydration and collection outside the tank body, it is adsorbed and regenerated for reuse.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, in particular to a granular carbon magnetic coagulation sedimentation tank. Background Art

[0002] In existing urban sewage treatment plants, with the continuous development and progress of industrial parks, the output of industrial wastewater in the parks is increasing. It is often discharged into urban sewage treatment plants for treatment directly or only after pretreatment. As a result, the proportion of industrial wastewater concentrated in urban sewage treatment plants is increasing, resulting in complex sewage composition and an increase in difficult-to-degrade organic matter. After biochemical treatment of sewage, the proportion of biodegradable organic matter in the wastewater is even lower, and it is difficult to use biochemical methods for deep treatment to treat difficult-to-degrade COD.

[0003] To further meet stricter discharge standards and reuse water requirements, advanced treatment processes often employ chemical and physical methods to further remove organic pollutants from water. Strong oxidation, flocculation and sedimentation, and filtration are commonly used to remove refractory pollutants. Activated carbon, due to its large surface area and strong adsorption capacity for organic matter, is widely used in sewage treatment plant upgrading and other treatment processes. It also improves the plant's ability to withstand shock loads and is often used as a safeguard for emergency high-concentration COD treatment.

[0004] Magnetic coagulation sedimentation tanks are preferred for wastewater upgrading projects due to their advantages in removing pollutants such as SS and TP, including high sedimentation efficiency, stable effluent performance, and a small footprint. However, the magnetic coagulation process is ineffective in removing organic matter, only removing approximately 20% of organic matter while removing suspended solids. In the prior art, for example, Chinese invention patent CN205740628U discloses a novel water purification system that utilizes a carbon-added magnetic flocculation sedimentation tank. This system effectively combines the adsorption properties of activated carbon with the high-speed sedimentation technology of magnetic flocculation. Compared to a simple magnetic flocculation sedimentation tank water purification system, this system adds a contact zone between powdered activated carbon and sewage, improving the sewage treatment process's purification capabilities for organic matter, color, turbidity, and other substances. It is typically used in the advanced treatment of municipal and industrial wastewater, removing COD and BOD and increasing the removal rates of color and turbidity.

[0005] However, the system uses powdered activated carbon, which increases the suspended solids load of the overall system, and the saturated powdered activated carbon is directly transported with the residual sludge to subsequent sludge treatment, resulting in a waste of resources. Summary of the Invention

[0006] The purpose of the present invention is to provide a granular carbon magnetic coagulation sedimentation tank to alleviate the technical problem in the prior art that activated carbon in water purification systems cannot be deeply recycled and utilized.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] A granular carbon magnetic coagulation sedimentation tank comprises: a reaction zone, a carbon adsorption zone and a sedimentation zone;

[0009] The reaction zone is connected to the water inlet pipe, and magnetic powder is placed in the reaction zone to absorb suspended matter in the sewage;

[0010] The sedimentation zone is arranged between the reaction zone and the carbon adsorption zone, and includes a buffer zone and a sludge sedimentation zone arranged from top to bottom. An input pipe is provided in the buffer zone, one end of the input pipe is connected to the output end of the reaction zone via a connector, and the bottom of the input pipe extends into the sludge sedimentation zone, and is used to evenly disperse the sewage in the reaction zone into the sludge sedimentation zone for solid-liquid separation. The buffer zone is connected to the input end of the carbon adsorption zone, and the sludge sedimentation zone is connected to a magnetic mud recovery device.

[0011] The carbon adsorption area is provided with a water distribution channel, a water inlet main pipe, an air stripping central pipe, a water distributor and a carbon backwasher; the water distribution channel is used to transport the water treated in the sludge sedimentation area to the water inlet main pipe, the bottom of the water inlet main pipe is connected to the water distributor, the center of the water inlet main pipe passes through the air stripping central pipe, and the carbon backwasher is connected to the upper end of the air stripping central pipe. Granular activated carbon is placed in the carbon adsorption area. The granular activated carbon is coal-based granular carbon and is used to adsorb organic pollutants in sewage.

[0012] The carbon adsorption zone is further provided with a carbon stripping carbon absorption and delivery port, and the carbon stripping carbon absorption and delivery port is located at the upper end of the carbon backwasher.

[0013] Furthermore, the reaction zone includes a first reaction tank, a second reaction tank and a third reaction tank connected in sequence;

[0014] The first reaction tank is connected to the water inlet pipe, and a coagulant is added into the first reaction tank;

[0015] Magnetic powder is placed in the second reaction tank to absorb suspended matter in the sewage and increase the specific gravity of the suspended matter;

[0016] The third reaction tank is connected to the buffer zone, and a flocculant is added into the third reaction tank;

[0017] Agitators are respectively provided in the first reaction tank, the second reaction tank and the third reaction tank.

[0018] Furthermore, an input pipe is provided in the buffer zone, and a mud hopper is provided at the bottom of the sludge sedimentation zone.

[0019] Furthermore, the magnetic mud recovery equipment includes a sludge pump and a magnetic mud separation and recovery device;

[0020] The sludge pump includes a sludge circulation pump and an external sludge pump, wherein the concentrated sludge at the bottom hopper of the sludge sedimentation area is transported to the second reaction tank through the sludge circulation pump;

[0021] The external sludge pump transports the sludge to the magnetic sludge separation and recovery device, separates and recovers the magnetic powder in the sludge for recycling.

[0022] Furthermore, an inclined pipe is arranged in the sludge sedimentation area, the inclined pipe is located above the central scraper, and a water collection channel is provided on one side of the buffer zone.

[0023] Furthermore, the water inlet main pipe is connected to a water distributor for central water distribution, and the lower end of the air lift central pipe is connected to an air lift pump.

[0024] Furthermore, an arch breaker is provided in the carbon adsorption zone, and the arch breaker is located below the water distributor.

[0025] Furthermore, it also includes an air compressor, a pressure-stabilizing storage tank and a cold dryer that are connected in sequence to provide an air source for the carbon backwasher and the arch breaker.

[0026] Furthermore, the carbon adsorption zone is provided with a drainage pipe, one end of the drainage pipe is connected to the carbon backwasher, and the other end is connected to the first reaction tank.

[0027] Furthermore, it also includes a carbon-water mixer and a carbon dehydrator. The carbon-water mixer is connected to the carbon adsorption area through a pipeline and is used to add coal-based granular carbon. The carbon dehydrator is connected to the gas lift carbon absorption and carbon delivery port through a pipeline and is used to dehydrate the discharged granular activated carbon and then regenerate it externally.

[0028] Based on the above technical solutions, the technical effects achieved by the present invention are analyzed as follows:

[0029] 1. Magnetic powder is placed in the reaction zone to adsorb suspended matter in the sewage and increase its specific gravity. The sedimentation zone includes a buffer zone and a sludge sedimentation zone arranged from top to bottom. An input pipe is provided in the buffer zone. One end of the input pipe is connected to the output end of the reaction zone via a connector. The bottom of the input pipe extends into the sludge sedimentation zone to evenly disperse the sewage in the reaction zone into the sludge sedimentation zone for solid-liquid separation. The buffer zone is connected to the input end of the carbon adsorption zone. The sludge sedimentation zone is connected to a magnetic mud recovery device to separate and recover the magnetic powder in the sludge for further recycling.

[0030] 2. The carbon adsorption area is equipped with a water distribution channel, a water inlet main, an air stripping central pipe, a water distributor, and a carbon backwasher. The water distribution channel is used to transport the water treated in the sludge sedimentation area to the water inlet main. The bottom of the water inlet main is connected to the water distributor. The center of the water inlet main passes through the air stripping central pipe. The carbon backwasher is connected to the upper end of the air stripping central pipe. Granular activated carbon is placed in the carbon adsorption area. Granular activated carbon is coal-based granular carbon. Relying on its large specific surface area and pollutant adsorption capacity, it further removes COD, color, and turbidity here, so that the effluent achieves the purpose of purification.

[0031] The carbon adsorption area is also provided with an air lift carbon absorption and carbon delivery port, which is located at the upper end of the carbon backwasher. The saturated carbon in the pool body is lifted and transported to the outside of the pool body by compressed air. After dehydration and collection outside the pool body, it is adsorbed and regenerated to achieve reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A schematic diagram of the structure of a granular carbon magnetic coagulation sedimentation tank provided in an embodiment of the present invention;

[0034] Figure 2 A schematic structural diagram of the carbon adsorption zone provided in an embodiment of the present invention.

[0035] icon:

[0036] 1- Mixer; 2- Connector; 3- Inlet pipe; 4- Central sludge scraper; 5- Mud hopper; 6- Sludge circulation pump; 7- External sludge pump; 8- Magnetic mud separation and recovery device; 9- Pipeline centrifugal pump; 10- Telescopic connector; 11- Water distribution channel; 12- Water distributor; 14- Carbon backwasher; 15- Air compressor; 16- Pressure-stabilizing storage tank; 17- Cold dryer; 18- Arch breaker; 19- Carbon extraction and suction port; 20-collecting channel; 21-drainage pipe; 22-water inlet pipe; 23-reaction zone; 24-carbon adsorption zone; 25-sedimentation zone; 26-buffer zone; 27-sludge sedimentation zone; 28-first reaction tank; 29-second reaction tank; 30-third reaction tank; 31-inclined pipe; 32-water collection channel; 33-water inlet main pipe; 34-gas lift center pipe; 35-lifting pump; 36-carbon-water mixer; 37-carbon dehydrator. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0038] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0039] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0040] like Figure 1 and Figure 2 As shown, the granular carbon magnetic coagulation sedimentation tank provided in this embodiment includes: a reaction zone 23, a carbon adsorption zone 24 and a sedimentation zone 25;

[0041] The reaction zone 23 is connected to the water inlet pipe 22. Magnetic powder is placed in the reaction zone 23 to absorb suspended matter in the sewage and increase the specific gravity of the suspended matter.

[0042] The sedimentation zone 25 is arranged between the reaction zone 23 and the carbon adsorption zone 24. The sedimentation zone 25 includes a buffer zone 26 and a sludge sedimentation zone 27 arranged from top to bottom. An input pipe 3 is provided in the buffer zone 26. One end of the input pipe (3) is connected to the output end of the reaction zone (23) through a connector (2). The bottom of the input pipe 3 extends into the sludge sedimentation zone 27 and is used to evenly disperse the sewage in the reaction zone 23 into the sludge sedimentation zone 27 for solid-liquid separation. The buffer zone 26 is connected to the input end of the carbon adsorption zone 26. The sludge sedimentation zone 27 is connected to a magnetic mud recovery device.

[0043] The carbon adsorption zone 24 is provided with a water distribution channel 11, a water inlet main 33, an air stripping central pipe 34, a water distributor 12, and a carbon backwasher 14. The water distribution channel 11 is used to transport water treated in the sludge settling zone 27 to the water inlet main 33. The bottom of the water inlet main is connected to the water distributor 12. The center of the water inlet main 33 passes through the air stripping central pipe 34. The carbon backwasher 14 is connected to the upper end of the air stripping central pipe 34. Granular activated carbon is placed in the carbon adsorption zone 24. The granular activated carbon is coal-based granular carbon and is used to adsorb organic pollutants in the sewage.

[0044] The carbon adsorption zone 24 is also provided with an air lift carbon absorption and delivery port 19, which is located at the upper end of the carbon backwasher 14. Atmospheric pressure air is used to lift and transport the saturated carbon in the tank body to the outside of the tank body, where it is dehydrated and collected and then adsorbed and regenerated for reuse.

[0045] The following is a detailed description of the structure of the granular carbon magnetic coagulation sedimentation tank:

[0046] In the optional solutions of the embodiments of the present invention, please refer to Figure 1 and Figure 2 The reaction zone 23 includes a first reaction pool 28, a second reaction pool 29 and a third reaction pool 30, and the second reaction pool 29 is arranged between the first reaction pool 28 and the third reaction pool 30; the three reaction pools are interconnected, and the side of the first reaction pool 28 facing away from the second reaction pool 29 is connected to the water inlet pipe 22; the side of the third reaction pool 30 facing away from the second reaction pool 29 is connected to the buffer zone 26.

[0047] Specifically, sewage flows from the water inlet pipe 22 into the first reaction tank 28. The first reaction tank 28, the second reaction tank 29, and the third reaction tank 30 are connected in series, each of which is a mixing and homogenizing stirring tank. Furthermore, the first reaction tank 28, the second reaction tank 29, and the third reaction tank 30 are all equipped with a stirrer 1, which is used to stir the liquid and solid mixture homogenously. Of course, the number of different reaction blocks should also be within the scope of protection of the present invention. Preferably, the power of the stirrer 1 is 1.5 kW.

[0048] The reaction zone 23 is divided into different reaction pools. Through the functions of the different reaction pools, the sewage is cleaned in stages, thereby improving the cleaning effect of the sewage.

[0049] In an optional solution of the embodiment of the present invention, a mixed reagent is provided in the first reaction tank 28 .

[0050] Specifically, a mixed reagent is placed in first reaction tank 28, including a coagulant and other chemical reagents. The coagulant destabilizes the colloidal particles in the sewage, while the other chemical reagents react in first reaction tank 28, converting the soluble phosphates in the sewage into particulate precipitates. The suspended matter then reagglomerates under the action of agitator 1 and flows into second reaction tank 29. Preferably, the mixed reagent concentration is 20 ppm.

[0051] A mixed reagent is provided in the first reaction tank 28 to destabilize the colloidal particles in the sewage and react with other chemical reagents, thereby reaggregating the sewage pollutants into dense flocs and achieving preliminary cleaning of the pollutants.

[0052] In an optional solution of the embodiment of the present invention, magnetic powder is provided in the second reaction tank 29 .

[0053] Specifically, magnetic powder is added to the second reaction tank 29, and the mixer 1 stirs the wastewater in the second reaction tank 29 to form suspended flocs with the magnetic powder as condensation nuclei, which then flow into the third reaction tank 30. Preferably, the magnetic powder has a specific gravity greater than 4.8, a particle size of 100 mesh, and a dosing concentration of 5g / L.

[0054] Magnetic powder is arranged in the second reaction tank 29 to condense the pollutants in the sewage to form dense flocs with high specific gravity, which are easier to be deposited and removed, thereby achieving deep cleaning of the sewage.

[0055] In an optional solution of the embodiment of the present invention, a flocculating agent is provided in the third reaction tank 30 .

[0056] Specifically, a flocculant is added to the third reaction tank 30 to aggregate the suspended flocs flowing from the second reaction tank 29 into larger, denser granular flocs through adsorption, bridging, and netting. Preferably, the concentration of the flocculant added is 1 ppm.

[0057] A flocculating agent is provided in the third reaction tank 30 to achieve agglomeration of suspended flocs, thereby achieving further cleaning of the sewage.

[0058] In an optional scheme of an embodiment of the present invention, the sedimentation zone 25 includes a buffer zone 26 above and a sludge sedimentation zone 27 below; an input pipe 3 is provided in the buffer zone 26, one end of the input pipe 3 is connected to the output end of the reaction zone 23 through a connector 2, and the bottom of the input pipe 3 extends into the sludge sedimentation zone 27, which is used to evenly disperse the sewage in the reaction zone 23 into the sludge sedimentation zone 27 for solid-liquid separation.

[0059] Specifically, after passing through the inlet pipe 3, the sewage enters the sludge settling area 27 for rapid sedimentation and sludge concentration. A central sludge scraper 4 is installed in the sludge settling area 27 to scrape and transport the concentrated sludge to the sludge hopper 5. Within the sludge settling area 27, the sludge rapidly settles and separates. Micro-flocs are trapped in the sludge settling area 27 by inclined pipes 31 and fall back to the bottom of the sludge settling area 27. Clean water is collected through a water collection channel 32 within the buffer zone 26. Preferably, the power of the central sludge scraper 4 is 0.75 kW.

[0060] The sewage is treated in the sludge sedimentation zone 27 to remove pollutants such as suspended solids, total phosphorus, color, turbidity, etc., and some organic matter is removed in the sludge sedimentation zone 27, which reduces the load of the carbon adsorption zone 24 and helps to delay the adsorption saturation of the activated carbon.

[0061] In an optional solution of the embodiment of the present invention, the sludge sedimentation area 27 is provided with a magnetic mud recovery device.

[0062] Specifically, the magnetic mud recovery equipment includes a sludge pump and a magnetic mud separation and recovery device 8. The sludge pump includes a sludge circulation pump 6 and an external sludge pump 7, wherein the concentrated sludge at the mud hopper 5 is transported to the third reaction tank 30 through the sludge circulation pump 6 for internal circulation in the system to enhance the effect of flocculation reaction; the external sludge pump 7 transports the sludge to the magnetic mud separation and recovery device 8, separates the magnetic powder in the sludge and recovers it to the system for recycling. Among them, the sealing water of the sludge pump and the flushing water of the magnetic mud separation and recovery device 8 are both transported by the pipeline centrifugal pump 9 to the water point of the corresponding equipment using tap water or recycled water. More preferably, the flow rate of the sludge circulation pump 6 is 10m 3 / h, head is 10m; external sludge pump 7, flow rate is 10m 3 / h, head is 10m; pipeline centrifugal pump 9 flow rate is 10m 3 / h, lift is 30m.

[0063] In an optional solution of this embodiment, the third reaction tank 30 is connected to the input pipe 3 via a connector 2 .

[0064] Specifically, the inlet pipe 3 uses a round trumpet-mouthed pipe for water distribution, and the sewage slowly flows into the bottom of the sludge sedimentation area 27. The water flows downward to bring downward inertia force to the floc particles, making the floc particles easier to settle without causing impact on the sludge layer in the sludge sedimentation area 27.

[0065] In an optional solution of this embodiment, an inclined pipe 31 is arranged in the sludge sedimentation area 27 , and the inclined pipe 31 is located above the central scraper 4 . A water collection channel 91 is provided on one side of the buffer zone 26 .

[0066] In an optional solution of this embodiment, the carbon adsorption zone 24 and the precipitation zone 25 are connected by a telescopic connector 10.

[0067] The telescopic connector 10 realizes the connection and penetration of the carbon adsorption area 24 and the sedimentation tank area 25.

[0068] In an optional solution of this embodiment, the water distributor 12 is configured to control the water flow from the water distributor 12 to the water inlet main 33 .

[0069] Specifically, wastewater treated in the previous step enters the water distributor 12 of the carbon adsorption zone 24 directly, and then flows evenly through the water distribution channel 11 into the water distributor 12 at the bottom of the carbon adsorption zone 24. The water distributor 12 uses a star-shaped central radial branch to distribute water, ensuring uniform water distribution across the bottom of the carbon adsorption zone 24. The water flows upward, while the carbon layer moves downward, ensuring uniform water distribution while increasing the suspended solids adsorption capacity of the carbon adsorption zone 24. Of course, other forms of the water distributor 12 are also within the scope of this invention.

[0070] The water distributor 12 is disposed at the bottom of the carbon adsorption zone 24 to achieve uniform water distribution and improve adsorption capacity.

[0071] In an optional embodiment of the present invention, carbon adsorption zone 24 utilizes granular activated carbon with a particle size of 2-6 mm, an iodine adsorption value of 800, and an adsorption load ratio of 10:1. Granular activated carbon has a large surface area and high pollutant adsorption capacity, improving the removal of organic matter, color, and turbidity, further purifying wastewater.

[0072] In the optional scheme of the embodiment of the present invention, in order to ensure the normal operation of the carbon adsorption zone 24, the granular activated carbon is cleaned by a carbon backwasher 14. Relying on the gas lift effect of compressed air, the granular activated carbon at the bottom of the carbon adsorption zone 24 is lifted to the action part of the carbon backwasher 14 through the gas lift center pipe 34 and the air lift pump 35. In the carbon backwasher 14, under the joint disturbance of compressed air and clean water, the suspended matter and desorbed pollutants attached to the granular activated carbon are cleaned, and the clean granular activated carbon falls from the carbon backwasher 14 into the carbon filter layer, and the entire carbon layer moves from top to bottom, which not only achieves the secondary cleaning of the upward flowing clean water, but also avoids the compaction of the carbon layer due to long-term fixation, and realizes the simultaneous backwashing of carbon during the adsorption operation of the system. More preferably, the compressed air for the carbon backwasher 14 and the arch breaker 18 is provided by the air compressor 15, the pressure stabilizing tank 16 and the cold dryer 17 system. More preferably, the gas volume of the compressed air is 1m 3 / min, rated pressure is 8 bar.

[0073] The carbon backwasher 14 cleans the granular activated carbon and realizes self-cleaning of the granular activated carbon.

[0074] In an optional solution of this embodiment, the carbon adsorption zone 24 includes a drainage pipe 21 , one end of the drainage pipe 21 is connected to the carbon backwasher 14 , and the other end is connected to the first reaction tank 28 .

[0075] The cleaning wastewater in the carbon backwasher 14 is discharged through the outlet of the drain pipe 21 and discharged into the front-stage first reaction tank 28 for coagulation and sedimentation treatment.

[0076] In an optional solution of this embodiment, an arch breaker 18 is provided in the carbon adsorption zone 24 , and the arch breaker 18 is located below the water distributor 12 .

[0077] Because granular activated carbon has a low density and light weight, in order to ensure that the carbon filter layer can effectively move downward for circulated backwashing during the backwashing process of the carbon backwasher 14, compressed air is introduced at the bottom of the carbon adsorption zone 24 and an arch breaker 18 is provided to prevent the activated carbon from being blocked and compacted during the circulation process.

[0078] In an optional solution of this embodiment, the air lift carbon absorption and carbon delivery port 19 provided in the carbon adsorption zone 24 lifts and delivers the saturated activated carbon in the carbon adsorption zone 24 to the outside of the carbon adsorption zone 24 through compressed air, and collects the activated carbon outside the carbon adsorption zone 24 and then regenerates it for adsorption to achieve reuse.

[0079] The optional scheme of this embodiment also includes a carbon-water mixer 36 and a carbon dehydrator 37. The carbon-water mixer 36 is connected to the carbon adsorption area 24 through a pipeline for feeding coal-based granular carbon. The carbon dehydrator 37 is connected to the gas lift carbon absorption and carbon delivery port 19 through a pipeline for dehydrating the discharged granular activated carbon and then regenerating it externally.

[0080] In an optional solution of this embodiment, the sewage is filtered through adsorption and then enters the collecting channel 20 and is discharged.

[0081] Wastewater is discharged from the collection channel 20 for reuse. The target effluent quality is SS ≤ 10mg / L, TP ≤ 0.1mg / L, COD ≤ 30mg / L, and the overall effluent quality meets the surface water Class IV standard.

[0082] The working principle of the granular carbon magnetic coagulation sedimentation tank provided in this embodiment is described below:

[0083] The integrated granular carbon magnetic coagulation sedimentation tank consists of three main parts: a reaction zone, a sedimentation zone, and a carbon adsorption zone. Sewage enters the reaction zone through an inlet pipe. The reaction zone is divided into three series-connected sections: the first, second, and third reaction tanks. These are mixing and homogenizing tanks equipped with agitators for homogenous mixing of liquids and solids.

[0084] A mixed agent is added to the first reaction tank, and the colloidal particles in the sewage are destabilized through the action of the coagulant. At the same time, a chemical reaction occurs in the first reaction tank to convert the soluble phosphate into a granular precipitate. Under the action of mixing and stirring, various suspended solids are re-agglomerated and enter the second reaction tank. Then, magnetic powder is added to the second reaction tank. The magnetic powder has a specific gravity greater than 4.8, a particle size of 100 mesh, and an addition concentration of 5g / L. After mixing and stirring, it is homogenized to form suspended flocs with magnetic powder as coagulation nuclei and then enters the third reaction tank. By adding flocculants at a concentration of 1ppm, the suspended flocs are agglomerated into larger particles and denser flocs through adsorption bridging, netting, etc., and then enter the buffer zone with the water flow. The buffer zone contains a connector and an input pipe. The connector connects the third reaction tank and the sludge sedimentation zone. The sewage enters the sedimentation zone after buffering for rapid sedimentation and sludge concentration.

[0085] The sludge settling area is equipped with a central scraper with a power of 0.75 kW, which scrapes the concentrated sludge to the hopper. The water inlet pipe uses a round bell-shaped pipe for water distribution, and the water flows slowly to the bottom of the settling area. The inlet water flows downward, exerting an inertial force on the floc particles, making them settle more easily without impacting the bottom mud layer. The sludge is rapidly settled and separated in the sludge settling area. The tiny flocs are trapped in the inclined pipe and eventually fall back into the tank body. The clean water is finally collected through the collection channel, achieving the removal of pollutants such as suspended solids, total phosphorus, color, and turbidity. Some COD is also removed here for the first time, with a removal efficiency of 20%. The carbon adsorption area reduces the organic matter load and helps delay the adsorption saturation of the activated carbon.

[0086] To enhance the flocculation effect, the concentrated sludge in the hopper of the sludge settling area is pumped to the third reaction tank via a circulating sludge pump. An external sludge pump then transports the sludge to the magnetic sludge separation and recovery system, where the magnetic powder in the sludge is separated and recycled back into the system for reuse, achieving a recovery efficiency of 99.7%. The sealing water for the sludge pump and the flushing water for the magnetic sludge system are both supplied by pipeline centrifugal pumps. Tap water or recycled water is pumped to the corresponding water points of the equipment.

[0087] The carbon adsorption zone and sludge settling zone are connected by a telescopic connector. Clean water flows directly into the carbon adsorption zone's water distributor, where it is evenly distributed to the bottom water distributor. The water distributor utilizes a star-shaped central radial branch to ensure uniform water distribution across the bottom of the carbon layer. The upward flow pattern not only ensures more uniform water distribution but also increases the adsorption tank's capacity for suspended solids, extending backwash intervals. The carbon adsorption tank utilizes granular activated carbon (GAC), a coal-based granular activated carbon with a particle size of 2-6mm, an iodine adsorption value of 800, and an adsorption load ratio of 10:1. Leveraging its large surface area and pollutant adsorption capacity, COD, color, and turbidity are further removed, resulting in purified effluent.

[0088] To ensure the normal operation of the carbon adsorption tank, the activated carbon is intermittently stripped and cleaned with carbon backwash gas, with a backwash cycle of 4-6 hours / day. Relying on the air stripping effect of compressed air, the carbon at the bottom is lifted to the top carbon backwasher through the compressed air pipe. Under the combined disturbance of compressed air and clean water, the suspended matter attached to the activated carbon particles and the desorbed pollutants are simultaneously cleaned out, and the clean activated carbon falls from the carbon backwasher path into the carbon filter layer to achieve secondary cleaning with the upward flowing clean water. The cleaning wastewater is discharged through the backwash drain outlet and discharged into the front reaction zone of the front magnetic coagulation sedimentation tank for coagulation and sedimentation treatment. The backwash water volume does not exceed 3%, and the pollutant removal purpose is finally achieved by discharging the residual sludge. The discharge time is intermittent 6 hours.

[0089] The compressed air for the carbon backwasher stripping gas source is provided by the air compressor, cold dryer, and pressure-stabilizing storage tank system. The compressed air volume is 1m 3 / min, rated pressure is 8bar, the activated carbon has low density and light weight, and the selected particle size is large. In order to ensure that the carbon filter layer can effectively move downward and circulate backwash during the backwash process, compressed air is introduced into the path around the bottom carbon guide hopper, and an air arch breaking device is set to avoid clogging and compaction of the activated carbon during the circulation process, and periodic gas arch breaking during backwashing.

[0090] The carbon adsorption unit also features an airlift carbon delivery port 19, which uses compressed air to lift saturated carbon from the cell body and transport it outside the cell body. It is then dehydrated and collected outside the cell body for adsorption regeneration for reuse. The regeneration cycle lasts for six months, and the final, adsorbed and filtered wastewater is returned to the outlet. Ultimately, after the project's advanced treatment process, the target effluent quality is SS ≤ 10mg / L, TP ≤ 0.1mg / L, and COD ≤ 30mg / L, achieving overall effluent quality that meets Class IV surface water standards.

[0091] In the technical solution of this application:

[0092] 1. By adopting a post-activated carbon adsorption unit, the activated carbon uses coal-based granular carbon, which avoids the mixing of activated carbon in the magnetic precipitation system. After the activated carbon is saturated with adsorption, it can be sucked out and transported outside the system for regeneration, achieving the recycling of resources;

[0093] 2. It has a high load capacity for removing organic matter and is resistant to shock loads. It is the optimal solution for effectively solving the problem of COD exceeding the standard in emergency treatment of sewage treatment plants.

[0094] 3. It can effectively remove pollutants such as suspended solids, total phosphorus, COD, color, turbidity, etc. It is suitable for upgrading and transforming urban sewage treatment plants and treating difficult-to-degrade organic matter in industrial wastewater.

[0095] 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A granular carbon magnetic coagulation sedimentation tank, characterized in that: include: reaction zone (23), carbon adsorption zone (24) and precipitation zone (25); The reaction zone (23) is connected to the water inlet pipe (22), and magnetic powder is placed in the reaction zone (23) to absorb suspended matter in the sewage; The sedimentation zone (25) is arranged between the reaction zone (23) and the carbon adsorption zone (24), and the sedimentation zone (25) includes a buffer zone (26) and a sludge sedimentation zone (27) arranged from top to bottom. An input pipe (3) is provided in the buffer zone (26), one end of the input pipe (3) is connected to the output end of the reaction zone (23) through a connector (2), and the bottom of the input pipe (3) extends into the sludge sedimentation zone (27) for uniformly dispersing the sewage in the reaction zone (23) into the sludge sedimentation zone (27) for solid-liquid separation. The buffer zone (26) is connected to the input end of the carbon adsorption zone (24), and the sludge sedimentation zone (27) is connected to a magnetic mud recovery device. The carbon adsorption zone (24) is provided with a water distribution channel (11), a water inlet main pipe (33), an air stripping central pipe (34), a water distributor (12) and a carbon backwasher (14); the water distribution channel (11) is used to transport the water treated in the sludge sedimentation zone (27) to the water inlet main pipe (33); the bottom of the water inlet main pipe is connected to the water distributor (12); the center of the water inlet main pipe (33) passes through the air stripping central pipe (34); the carbon backwasher (14) is connected to the upper end of the air stripping central pipe (34); granular activated carbon is placed in the carbon adsorption zone (24); the granular activated carbon is coal-based granular carbon and is used to adsorb organic pollutants in sewage; The carbon adsorption zone (24) is further provided with a carbon delivery port (19) for gas lift carbon absorption, and the carbon delivery port (19) is located at the upper end of the carbon backwasher (14); The reaction zone (23) includes a first reaction tank (28), a second reaction tank (29) and a third reaction tank (30) connected in sequence; The first reaction tank (28) is in communication with the water inlet pipe (22), and a coagulant is placed in the first reaction tank (28); Magnetic powder is placed in the second reaction tank (29) to absorb suspended matter in the sewage and increase the specific gravity of the suspended matter; The third reaction tank (30) is connected to the buffer zone (26), and a flocculant is added into the third reaction tank (30); A stirrer (1) is respectively provided in the first reaction tank (28), the second reaction tank (29) and the third reaction tank (30); The magnetic mud recovery equipment includes a sludge pump and a magnetic mud separation and recovery device (8); The sludge pump comprises a sludge circulation pump (6) and an external sludge pump (7), wherein the concentrated sludge at the bottom hopper (5) of the sludge sedimentation area (27) is transported to the second reaction tank (29) through the sludge circulation pump (6); The external sludge pump (7) transports the sludge to the magnetic sludge separation and recovery device (8), separates and recovers the magnetic powder in the sludge for further recycling; The carbon adsorption zone (24) is provided with a drainage pipe (21), one end of the drainage pipe (21) is connected to the carbon backwasher (14), and the other end is connected to the first reaction tank (28).

2. The granular carbon magnetic coagulation sedimentation tank according to claim 1, characterized in that: A mud hopper (5) is provided at the bottom of the sludge sedimentation area (27).

3. The granular carbon magnetic coagulation sedimentation tank according to claim 2, characterized in that: An inclined pipe (31) is arranged in the sludge sedimentation area (27), and the inclined pipe (31) is located above the central sludge scraper (4). A water collection channel (91) is provided on one side of the buffer zone (26).

4. The granular carbon magnetic coagulation sedimentation tank according to claim 1, characterized in that: The water inlet main pipe (33) is connected to the water distributor (12) for central water distribution, and the lower end of the air lift central pipe is connected to an air lift pump (35).

5. The granular carbon magnetic coagulation sedimentation tank according to claim 1, characterized in that: An arch breaker (18) is provided in the carbon adsorption zone (24), and the arch breaker (18) is located below the water distributor (12).

6. The granular carbon magnetic coagulation sedimentation tank according to claim 5, characterized in that: It also includes an air compressor (15), a pressure-stabilizing storage tank (16) and a cold dryer (17) which are connected in sequence and are used to provide an air source to the carbon backwasher (14) and the arch breaker (18).

7. The granular carbon magnetic coagulation sedimentation tank according to claim 1, characterized in that: It also includes a carbon-water mixer (36) and a carbon dehydrator (37). The carbon-water mixer (36) is connected to the carbon adsorption area (24) through a pipeline and is used to add coal-based granular carbon. The carbon dehydrator (37) is connected to the gas lift carbon absorption carbon delivery port (19) through a pipeline and is used to dehydrate the discharged granular activated carbon and then regenerate it externally.

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