A sewage pretreatment device with hierarchical impurity removal

Abstract

The present application relates to a kind of sewage pretreatment device of hierarchical impurity removal, including a treatment pool body, treatment pool body inside is sequentially separated into flocculation sedimentation tank, filter tank and air floatation tank, the top of flocculation sedimentation tank is equipped with flocculating agent import, for adding flocculating agent, bottom is equipped with collection tank, for collecting sediment, inside is equipped with aeration assembly;Filter tank is equipped with at least one filter screen;Air floatation tank is equipped with several biological carriers, for adsorbing and treating floating oil pollutants, the downstream side of air floatation tank is equipped with oil collection tank, for collecting excess floating oil pollutants.The present application concentrates flocculation sedimentation, filtration and air floatation in a treatment pool body, equipment is concentrated, saves the pipeline and water delivery pump of intermediate connection, uses biological carrier adsorption and preliminary treatment floating oil in sewage in air floatation tank, and the floating oil that is not treated is collected by oil collection tank.

Description

Technical Field

[0001] This invention belongs to the field of wastewater pretreatment technology, and specifically relates to a wastewater pretreatment device for graded impurity removal. Background Technology

[0002] Industrial wastewater is characterized by its complex composition and significant variations in the content of its components. Direct discharge without treatment can pollute the environment and harm human health. In recent years, the resource utilization of wastewater has gained importance, playing a crucial role in alleviating the water supply and demand imbalance in my country, reducing water pollution, and ensuring water ecological security. Pretreatment technology plays a vital role in wastewater treatment, stabilizing or improving influent water quality and providing a solid foundation for subsequent biological or physicochemical treatment processes. However, existing industrial wastewater pretreatment devices generally use screens for simple interception of large particles, with minimal effect on removing fine suspended solids and floating oil. Equipping each pretreatment unit separately would inevitably increase floor space and operating costs; furthermore, existing industrial wastewater pretreatment devices face difficulties in collecting and cleaning the residue and floating oil after filtration and sedimentation, requiring substantial manpower and financial resources. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a wastewater pretreatment device for graded impurity removal, comprising a treatment tank, which is internally divided into a flocculation sedimentation tank, a filtration tank, and an air flotation tank. The top of the flocculation sedimentation tank is provided with a flocculant inlet for adding flocculant, and the bottom is provided with a collection tank for collecting sediment. An aeration assembly is provided inside the tank.

[0004] The filter tank is equipped with at least one filter screen; the flotation tank contains several biological carriers for adsorbing and treating floating oil pollutants; and the downstream side of the flotation tank is equipped with an oil collection tank for collecting excess floating oil pollutants.

[0005] This invention integrates flocculation sedimentation, filtration, and flotation into a single treatment tank. Wastewater flows sequentially through the flocculation sedimentation tank, filtration tank, and flotation tank, completing pretreatment. This centralized equipment eliminates the need for intermediate connecting pipes and pumps, thus reducing construction and management costs. After flocculation sedimentation and filtration, solid impurities in the wastewater are largely removed. In the flotation tank, a biological carrier adsorbs and preliminarily treats the floating oil in the wastewater; untreated floating oil is collected in an oil collection tank.

[0006] Optionally, the aeration assembly of the flocculation sedimentation tank includes several aeration pipes, which are evenly arranged along the circumference of the flocculation sedimentation tank.

[0007] The aeration pipe includes a main aeration pipe and several aeration branch pipes evenly distributed along the main aeration pipe. Gas is input at the top of the main aeration pipe and an aeration port is provided at the bottom. The top of the aeration branch pipe is connected to the corresponding main aeration pipe, and several branch aeration ports are evenly distributed on the side wall.

[0008] The arrangement direction of the flocculation sedimentation tank, the filtration tank and the flotation tank in the treatment tank is defined as the length direction, and the direction perpendicular to the length direction is defined as the width direction.

[0009] Further optionally, the aeration main pipe forms a first tilt angle with the vertical direction and a second tilt angle with the length direction of the treatment tank, so that the aeration main pipe is tilted for aeration.

[0010] The aeration pipes are set vertically, and the aeration ports of the aeration pipes form a third inclination angle with the length of the treatment tank, which expands the range of inclined aeration.

[0011] Optionally, the filter tank includes several horizontally arranged filter screens, and the aperture of the filter screens gradually decreases from top to bottom;

[0012] The top plate of the filter tank is detachable, and the two sides of the filter screen are slidably connected to the two opposite side walls of the filter tank. A drive device is provided above the filter tank to connect the filter screen and drive the filter screen to move up and down, making it easy to clean the filter screen.

[0013] Optionally, the filter tank has at least two vertical recessed slides on its two opposite sidewalls corresponding to the positions of the filter screen plate. The filter screen plate has a slider corresponding to the position of the slides. The slider is engaged in the slide and is connected to the drive device to control the lifting and lowering of the filter screen plate.

[0014] Optionally, the flotation tank is provided with a jetting device, several biological carriers, a purging device, an oil collection tank and a water inlet in sequence from the upstream side to the downstream side. The jetting device is located at the bottom of the flotation tank and uses the water inlet of the flotation tank and the outside air to generate bubbles at the bottom of the upstream side of the flotation tank to capture oil droplets.

[0015] Several biological carriers are evenly arranged in the length and width directions of the air flotation tank. The biological carriers are vertically arranged spirals and are evenly distributed with first through holes. The surface of the biological carriers is loaded with aerobic microorganisms.

[0016] The oil collection tank is open and located on the upper part of the downstream side of the flotation tank. The top opening of the oil collection tank is flush with the liquid surface of the flotation tank. The water outlet is located at the bottom of the flotation tank and is used to discharge the pretreated water.

[0017] Further optionally, the spraying device includes a spray pipe and an air pipe. The inlet of the spray pipe passes through the side wall and is connected to the bottom of the filter tank. The water treated at the bottom of the filter tank is introduced into the spray pipe. The inner diameter of the spray pipe first decreases and then increases, so that the spray pipe has a shape that is large at both ends and small in the middle, similar to a Venturi tube.

[0018] The top end of the air pipe extends beyond the liquid surface of the flotation tank and is connected to the outside air, while the bottom end of the air pipe is connected to the middle of the injection pipe.

[0019] Further optionally, the biological carrier is wound around the vertical direction in concentric circles to form a spiral shape with the same spiral interval and the same inner diameter in the vertical direction;

[0020] The top of the biological carrier is connected to a motor above the air flotation tank, which drives the biological carrier to rotate via a rotating shaft.

[0021] Further optionally, the two sides of the biological carrier are respectively covered with carrier attachment pads, the carrier attachment pads include an inner pad that is close to the biological carrier and an outer pad that is away from the biological carrier, the space between the inner pad and the outer pad is filled with a solid carbon source, and the carrier attachment pads are provided with a second through hole corresponding to the position of the first through hole. The two carrier attachment pads are bound to the biological carrier by passing a rope through the first through hole and the second through hole.

[0022] Optionally, the purging device is connected to the rotating device via a connecting rod. The rotating device is mounted on a bracket to fix the rotating device. The rotating device can rotate on a horizontal plane, causing the connecting rod to swing back and forth along the width of the treatment tank, thereby enabling the purging device to purge a larger area of ​​the flotation tank. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a wastewater pretreatment device for graded impurity removal;

[0024] Figure 2 This is a schematic diagram of the structure of the flocculation sedimentation tank and the filter tank;

[0025] Figure 3 This is a schematic diagram of the air flotation tank.

[0026] Figure 4 This is a schematic cross-sectional view of a biological carrier.

[0027] In the attached diagram, 1-treatment tank, 2-flocculation sedimentation tank, 3-filtration tank, 4-air flotation tank, 5-collection tank, 6-flocculating agent inlet, 7-filter screen, 8-biological carrier, 9-oil collection tank, 10-main aeration pipe, 11-aeration branch pipe, 12-first water inlet, 13-second water inlet, 14-product water inlet, 15-drive device, 16-jetting device, 17-purging device, 18-connecting rod, 19-jetting pipe, 20-air pipe, 21-inner pad, 22-outer pad, 23-solid carbon source, 24-rotating device. Detailed Implementation

[0028] This embodiment provides a wastewater pretreatment device for graded impurity removal, such as... Figures 1-4As shown, it includes a treatment tank 1, which is divided into a flocculation sedimentation tank 2, a filter tank 3 and an air flotation tank 4 in sequence. The top of the flocculation sedimentation tank 2 is provided with a flocculant inlet 6 for adding flocculant, and the bottom is provided with a collection tank 5 for collecting sediment. An aeration component is provided inside.

[0029] The filter tank 3 is equipped with at least one filter screen 7; the air flotation tank 4 contains several biological carriers 8 for adsorbing and treating floating oil pollutants; and the downstream side of the air flotation tank 4 is equipped with an oil collection tank 9 for collecting excess floating oil pollutants.

[0030] Optionally, the aeration assembly of the flocculation sedimentation tank 2 includes several aeration pipes, which are evenly arranged along the circumference of the flocculation sedimentation tank 2.

[0031] The aeration pipe includes an aeration main pipe 10 and several aeration branch pipes 11 evenly arranged along the aeration main pipe 10. The top end of the aeration main pipe 10 is connected to an aeration device for inputting gas, and the bottom end is provided with an aeration port. The top end of the aeration branch pipe 11 is connected to the corresponding aeration main pipe 10, and several branch aeration ports are evenly arranged on the side wall.

[0032] The arrangement direction of the flocculation sedimentation tank 2, the filter tank 3 and the air flotation tank 4 in the treatment tank 1 is defined as the length direction, and the direction perpendicular to the length direction is defined as the width direction.

[0033] Further optionally, the aeration main pipe 10 forms a first tilt angle with the vertical direction and a second tilt angle with the length direction of the treatment tank 1, so that the aeration main pipe 10 is tilted for aeration.

[0034] The aeration branch pipe 11 is set vertically, and the aeration port of the aeration branch pipe 11 forms a third inclination angle with the length direction of the treatment tank body 1, which expands the range of inclined aeration.

[0035] Further optionally, the first tilt angle is 30-70°, the second tilt angle is 10-30°, and the third tilt angle is 10-40°, with the second tilt angle being smaller than the third tilt angle, so that the torsion amplitude of the aeration branch pipe 11 is greater than that of the aeration main pipe 10.

[0036] To improve the contact efficiency between wastewater and flocculant in the flocculation sedimentation tank 2, this invention utilizes aeration to agitate the wastewater without adding a power stirring device, ensuring sufficient contact between the wastewater and flocculant and improving flocculation efficiency. The main aeration pipe 10 is at an angle to the vertical direction, allowing for downward aeration. The main aeration pipe 10 also forms an angle with the length of the treatment tank 1, i.e., with the water flow direction. Aeration creates a swirling flow, promoting wastewater agitation and the settling of the formed flocs. The aeration outlets of the branch aeration pipes 11 also form an angle with the water flow direction, and these outlets are located on the sidewalls of the branch aeration pipes 11, creating another swirling flow around the swirling flow formed by the main aeration pipe 10. Because several branch aeration pipes 11 are arranged along the length of the main aeration pipe 10, and because the second and third inclination angles are different, it is equivalent to forming several swirling flows from the inside out, increasing the dimensionality of the swirling flow and improving the aeration flocculation effect.

[0037] Optionally, the flocculant inlet 6 is connected to a flocculant dosing device via a pipeline, such as a flocculant tank with a valve. The flocculant can be a commonly used flocculant, such as a composite flocculant with vermiculite inorganic minerals and cationic polyacrylamide as the main raw materials. This can not only make small suspended solids form larger flocs, improving or accelerating sedimentation and separation, but also remove ammonia nitrogen, total phosphorus, and reduce COD, thereby reducing the load on subsequent biochemical treatment.

[0038] Optionally, the two ends of the collection trough 5 are connected to two opposite sides of the flocculation sedimentation tank 2, which can be parallel to or perpendicular to the water flow direction; the two sides of the collection trough 5 are inclined to facilitate solid impurities to slide into the collection trough 5.

[0039] Optionally, the upstream side wall of the flocculation sedimentation tank 2 is provided with an inlet for inputting sewage; the downstream side wall of the flocculation sedimentation tank 2 is the upstream side wall of the filter tank 3, and the upper part of the side wall is provided with a first water inlet 12 for inputting the flocculated water in the flocculation sedimentation tank 2 into the filter tank 3.

[0040] Optionally, the filter tank 3 includes a plurality of horizontally arranged filter screens 7, the aperture of the filter screens 7 gradually decreasing from top to bottom, filtering solid impurities in the sewage step by step to improve the filtration effect;

[0041] The top plate of the filter tank 3 is detachable. The two sides of the filter screen plate 7 are slidably connected to the two opposite side walls of the filter tank 3. A drive device 15 is provided above the filter tank 3 to connect the filter screen plate 7 and drive the filter screen plate 7 to move up and down, which facilitates cleaning of the filter screen plate 7.

[0042] Optionally, the filter tank 3 has at least two vertical recessed slides on its two opposite sidewalls corresponding to the positions of the filter screen plate 7. The filter screen plate 7 has a slider corresponding to the position of the slide, the slider is engaged in the slide, and the slider is connected to the drive device 15 to control the lifting and lowering of the filter screen plate 7.

[0043] In one specific implementation, the upstream and downstream sidewalls of the filter tank 3 are each provided with two opposing vertical slides. A slider is provided for each filter screen plate 7 corresponding to the slide position. Several sliders for filter screen plates 7 are sequentially arranged within the same slide, meaning that several filter screen plates 7 share the same slide, and the vertical relationship of the filter screen plates 7 cannot be changed. The driving device 15 can be a hydraulic cylinder. Each hydraulic cylinder is connected to the sliders of different filter screen plates 7 within a slide via a hydraulic rod. All hydraulic cylinders operate simultaneously, driving several filter screen plates 7 to move together. When the filter screen plates 7 are removed from the filter tank 3, they can be cleaned and then returned to the filter tank 3 along the same path.

[0044] Optionally, the downstream sidewall of the filter tank 3 is the upstream sidewall of the flotation tank 4, and a second water inlet 13 is provided at the lower part of the sidewall for inputting the filtered water in the filter tank 3 into the flotation tank 4.

[0045] Optionally, the flotation tank 4 is provided with a jetting device 16, several biological carriers 8, a purging device 17, an oil collection tank 9 and a water production port 14 in sequence from the upstream side to the downstream side. The jetting device 16 is located at the bottom of the flotation tank 4 and uses the water inlet of the flotation tank 4 and the outside air to generate bubbles at the bottom of the upstream side of the flotation tank 4 to capture oil droplets.

[0046] Several biological carriers 8 are evenly arranged in the length and width directions of the flotation tank 4. The biological carriers 8 are vertically arranged spirals and are evenly distributed with first through holes. The surface of the biological carriers 8 is loaded with aerobic microorganisms. The first through holes allow the air bubbles in the flotation tank 4 to swirl upwards along the biological carriers 8 and to flow laterally or obliquely through the first through holes, thereby increasing the hydraulic shear force, increasing the contact time between the gas and the wastewater, making better use of the oxygen in the water, and improving the biochemical treatment effect.

[0047] The oil collection tank 9 is an open type and is located on the upper part of the downstream side of the flotation tank 4. The top opening of the oil collection tank 9 is flush with the liquid surface of the flotation tank 4. The water outlet 14 is located at the lower part of the flotation tank 4 and is used to discharge the pretreated water.

[0048] Further optionally, the spraying device 16 includes a spray pipe 19 and an air pipe 20. The inlet of the spray pipe 19 passes through the side wall and is connected to the bottom of the filter tank 3, so that the water treated at the bottom of the filter tank 3 is introduced into the spray pipe 19. The inner diameter of the spray pipe 19 first decreases and then increases, so that the spray pipe 19 has a shape that is large at both ends and small in the middle, similar to a Venturi tube.

[0049] The top end of the air pipe 20 extends out of the liquid surface of the air flotation tank 4 and is connected to the outside air, while the bottom end of the air pipe 20 is connected to the middle of the injection pipe 19.

[0050] After water enters the jet pipe 19, the flow rate increases and the pressure decreases as it passes through its narrow middle section. Using negative pressure, outside air is drawn in through the air pipe 20. The air mixes with the water inside the jet pipe 19 and is finally ejected from the outlet of the jet pipe 19. The air forms small bubbles that enter the flotation tank 4, which increases the dissolved oxygen in the wastewater, helps the biological carrier 8 to carry out biochemical processes and treat the wastewater. The small bubbles can also carry oil droplets in the wastewater upward to the liquid surface. After being purged by the purging device 17, they enter the oil collection tank 9, completing the removal of floating oil.

[0051] Further optionally, the biological carrier 8 is wound around in circles along the vertical direction to form a spiral shape with the same spiral interval and the same inner diameter in the vertical direction;

[0052] The top of the biological carrier 8 is connected to a motor above the air flotation tank 4, which is used to drive the biological carrier 8 to rotate via a rotating shaft.

[0053] Optionally, the two sides of the biological carrier 8 are respectively covered with carrier attachment pads. The carrier attachment pads include an inner pad 21 that is close to the biological carrier 8 and an outer pad 22 that is away from the biological carrier 8. A solid carbon source 23 is filled between the inner pad 21 and the outer pad 22. The carrier attachment pads are provided with a second through hole corresponding to the position of the first through hole. The two carrier attachment pads are bound to the biological carrier 8 by passing a rope through the first through hole and the second through hole.

[0054] Further optionally, both the inner pad 21 and the outer pad 22 are several layers of non-woven fabric, with a solid carbon source sandwiched in the middle of the non-woven fabric. Combined with the binding effect of the rope, the solid carbon source can be fixed.

[0055] The solid carbon source 23 consists of equal masses of soybean residue, crushed peanuts, and sludge blocks, which is beneficial for microorganisms loaded on the carrier attachment pad to utilize as a carbon source and promote the growth and reproduction of microorganisms on the biological carrier 8.

[0056] The biological carrier 8 of this invention, while treating wastewater, also features a structure and rotational characteristics that effectively agitate the wastewater within the flotation tank 4, promoting gas-liquid contact, improving treatment efficiency, and simultaneously facilitating the capture of oil droplets by air bubbles. The biological carrier 8 has carrier attachment pads covering both its front and back sides, serving as the actual attachment area for microorganisms. These pads have a large specific surface area, allowing for a large microbial load. Solid carbon source 23 is filled within the carrier attachment pads to provide additional carbon for the attached microorganisms. Due to the coordination of the first and second through holes, the carrier attachment pads and the internal solid carbon source 23 can be segmentally secured with ropes to prevent detachment.

[0057] Optionally, the purging device 17 is connected to the rotating device 24 via the connecting rod 18. The rotating device 24 is mounted on the bracket to fix the rotating device 24. The rotating device 24 can rotate on the horizontal plane, so that the connecting rod 18 swings back and forth along the width direction of the treatment tank 1, thereby enabling the purging device 17 to purge a larger area of ​​the flotation tank 4.

[0058] Untreated or unadsorbed oil by the biological carrier 8 moves to the purging device 17 under the action of water flow and jetting device 16, and then enters the oil collection tank 9 after being purged by the purging device 17. The purging device 17 can be any commonly used purging device in the art. The support can be suspended and extend from top to bottom to the liquid surface, or it can be installed inside the flotation tank 4.

[0059] Optionally, the oil collection tank 9 is arranged along the width direction of the treatment tank 1, and can receive most of the floating oil in the flotation tank 4.

Claims

1. A wastewater pretreatment device for graded impurity removal, characterized in that, It includes a treatment tank, which is divided into a flocculation sedimentation tank, a filtration tank and an air flotation tank. The top of the flocculation sedimentation tank is equipped with a flocculant inlet for adding flocculant, and the bottom is equipped with a collection tank for collecting sediment. An aeration component is installed inside the tank. The filter tank is equipped with at least one filter screen; the flotation tank is equipped with several biological carriers for adsorbing and treating floating oil pollutants; and the downstream side of the flotation tank is equipped with an oil collection tank for collecting excess floating oil pollutants. The aeration assembly of the flocculation sedimentation tank includes several aeration pipes, which are evenly arranged along the circumference of the flocculation sedimentation tank. The aeration pipe includes a main aeration pipe and several aeration branch pipes evenly distributed along the main aeration pipe. Gas is input at the top of the main aeration pipe and an aeration port is provided at the bottom. The top of the aeration branch pipe is connected to the corresponding main aeration pipe, and several branch aeration ports are evenly distributed on the side wall. The aeration main pipe forms a first tilt angle with the vertical direction and a second tilt angle with the length direction of the treatment tank, so that the aeration main pipe is tilted for aeration. The aeration pipes are set vertically, and the aeration ports of the aeration pipes form a third inclination angle with the length of the treatment tank, which expands the range of inclined aeration. The second tilt angle is smaller than the third tilt angle, and through aeration, several swirling currents are formed from the inside to the outside; The dissolved air flotation tank is provided with a jetting device, several biological carriers, a purging device, an oil collection tank and a water inlet in sequence from the upstream side to the downstream side. The jetting device is located at the bottom of the dissolved air flotation tank and uses the water inlet of the dissolved air flotation tank and the outside air to create bubbles at the bottom of the upstream side of the dissolved air flotation tank to capture oil droplets. Several biological carriers are evenly arranged in the length and width directions of the air flotation tank. The biological carriers are vertically arranged spirals and are evenly distributed with first through holes. The surface of the biological carriers is loaded with aerobic microorganisms. The oil collection tank is open and located on the upper part of the downstream side of the flotation tank. The top opening of the oil collection tank is flush with the liquid surface of the flotation tank. The water outlet is located at the bottom of the flotation tank and is used to discharge the pretreated water. The biological carrier is wound in circles along the vertical direction to form a spiral shape with the same spiral intervals and the same inner diameter in the vertical direction; The top of the biological carrier is connected to a motor above the air flotation tank, which drives the biological carrier to rotate via a rotating shaft.

2. The wastewater pretreatment device for graded impurity removal according to claim 1, characterized in that, The filter tank includes several horizontally arranged filter screens, and the aperture of the filter screens gradually decreases from top to bottom; The top plate of the filter tank is detachable, and the two sides of the filter screen are slidably connected to the two opposite side walls of the filter tank. A drive device is provided above the filter tank to connect the filter screen and drive the filter screen to move up and down, making it easy to clean the filter screen.

3. The wastewater pretreatment device for graded impurity removal according to claim 2, characterized in that, The filter tank has at least two vertical recessed slides on its two opposite side walls corresponding to the positions of the filter screen plate. The filter screen plate has a slider corresponding to the position of the slides. The slider is engaged in the slide and is connected to the drive device to control the lifting and lowering of the filter screen plate.

4. The wastewater pretreatment device for graded impurity removal according to claim 1, characterized in that, The spraying device includes a spray pipe and an air pipe. The inlet of the spray pipe passes through the side wall and is connected to the bottom of the filter tank. The water treated at the bottom of the filter tank is introduced into the spray pipe. The inner diameter of the spray pipe first decreases and then increases, so that the spray pipe has a shape that is large at both ends and small in the middle. The top end of the air pipe extends beyond the liquid surface of the flotation tank and is connected to the outside air, while the bottom end of the air pipe is connected to the middle of the injection pipe.

5. The wastewater pretreatment device for graded impurity removal according to claim 4, characterized in that, The two sides of the biological carrier are respectively covered with carrier attachment pads. The carrier attachment pads include an inner pad that is close to the biological carrier and an outer pad that is far away from the biological carrier. The space between the inner pad and the outer pad is filled with a solid carbon source. The carrier attachment pads are provided with a second through hole corresponding to the position of the first through hole. The two carrier attachment pads are bound to the biological carrier by passing a rope through the first through hole and the second through hole.

6. The wastewater pretreatment device for graded impurity removal according to claim 1, characterized in that, The purging device is connected to the rotating device via a connecting rod. The rotating device is mounted on a bracket to fix the rotating device. The rotating device can rotate on a horizontal plane, causing the connecting rod to swing back and forth along the width of the treatment tank, thereby enabling the purging device to purge a large area of ​​the flotation tank.

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