Efficient desliming system and method for sugar beet sugar wastewater

Abstract

The application discloses a kind of high-efficiency desliming system and method of sugar beet sugar-making wastewater. Among them, the high-efficiency desliming system of sugar beet sugar-making wastewater includes radial flow sedimentation tank, oxidation pond, A sedimentation tank, B sedimentation tank, grating machine, water collecting tank, settler, silt flow director and horizontal centrifuge, the sewage outlet of grating machine is connected with the inlet of water collecting tank by pipeline, the outlet of water collecting tank is connected with the inlet of settler by sewage pump and pipeline, silt flow director is located just below the lower end outlet of settler, the outlet of silt flow director is connected with the inlet of horizontal centrifuge by slurry pump and slurry conveying pipeline.The application is flexibly switched by A sedimentation tank and B sedimentation tank in series and parallel, combined with grating machine, settler, horizontal centrifuge to form sludge treatment system, effectively realize high-efficiency desliming of sugar beet sugar-making wastewater, greatly reduce subsequent wastewater treatment load, reduce reagent consumption, while improving sludge dewatering efficiency, avoid environmental risk in the process of dredging and transportation.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology in beet sugar production, specifically to a highly efficient sludge removal system and method for beet sugar production wastewater. Background Technology

[0002] The sugar production process of sugar beets generates a large amount of wastewater. The wastewater not only contains solid impurities that are difficult to settle, such as mud, beet skins, and plant debris, but also accumulates a large amount of soluble organic pollutants such as pectin and protein when processing rotten or frozen sugar beets. The wastewater has a complex composition and is difficult to treat.

[0003] In existing technology, sugar production wastewater is first sent to a radial flow sedimentation tank for solid-liquid separation. The clarified liquid at the top of the sedimentation tank is reused in the beet washing process. The highly polluted wastewater at the bottom, which is rich in sludge, beet fragments, pectin, and protein organic matter, is transported to an oxidation pond for deep settling. The clarified water at the top of the oxidation pond is transported to a wastewater treatment plant for biochemical treatment. The sediment at the bottom of the pond continues to accumulate and is dredged and disposed of after the production cycle ends.

[0004] However, existing methods for treating sugar production wastewater have significant technical flaws. Light organic matter such as beet peel has extremely poor settling properties, and pectin, being a soluble organic compound, cannot be removed through physical sedimentation. This results in high COD concentrations and measured turbidity exceeding 200 NTU in the effluent from oxidation ponds, with the bottom sludge having a solids content of only 8%–12%, leading to severe mud-water mixing. High-organic-load wastewater entering subsequent biological treatment systems significantly impacts the operational stability of wastewater treatment facilities, often requiring production reduction and control, severely restricting continuous sugar production. Furthermore, the wastewater has a pH of 4.5–6.5, exhibiting weak acidity, necessitating the addition of large amounts of alkaline agents for neutralization, which are costly. Simultaneously, conventional excavator dredging of oxidation ponds poses significant environmental safety hazards. Dredging operations violently disturb the bottom sludge, causing the sludge moisture content to rise above 80%, significantly increasing the risk of material leakage during transport. The operation process also easily damages the anti-seepage structure of the oxidation pond, posing environmental risks of wastewater leakage and soil and groundwater pollution. Summary of the Invention

[0005] The primary objective of this invention is to overcome the shortcomings of existing technologies and provide a highly efficient sludge removal system for sugar beet processing wastewater.

[0006] The first objective of this invention is achieved through the following technical solution: a high-efficiency sludge dewatering system for sugar beet processing wastewater, comprising a radial flow sedimentation tank, an oxidation pond, a sedimentation tank A located below the wastewater outlet of the radial flow sedimentation tank, a sedimentation tank B located below the sedimentation tank A, a bar screen located below the sedimentation tank B, a collection tank located below the bar screen, an inverted cone-shaped settling device, a sludge guide, and a horizontal centrifuge. The oxidation pond is located below the sedimentation tank B. The wastewater outlet of the radial flow sedimentation tank is connected to the top inlet of the sedimentation tank A and the top inlet of the sedimentation tank B via a first three-way valve and pipeline. The middle outlet of sedimentation tank A is connected to the inlet of the bar screen and the top inlet of sedimentation tank B via a second three-way valve and pipeline. The middle outlet of sedimentation tank B is connected to the inlet of the bar screen and the inlet of the oxidation pond via a third three-way valve and pipeline. The wastewater outlet of the bar screen is connected to the inlet of the water collection tank via pipeline. The outlet of the water collection tank is connected to the inlet of the sedimentation unit via a wastewater pump and pipeline. The sludge guide is located directly below the lower outlet of the sedimentation unit. The outlet of the sludge guide is connected to the inlet of the horizontal centrifuge via a sludge pump and sludge conveying pipeline.

[0007] Furthermore, it also includes a coagulant aid tank and a flocculant tank. The coagulant aid tank is connected to the inlet of the settling tank through a first dosing pump, a first dosing branch pipe, and a main dosing pipeline. The flocculant tank is connected to the inlet of the settling tank through a second dosing pump, a second dosing branch pipe, and the main dosing pipeline. A rotor flow meter is installed on the main dosing pipeline. The main dosing pipeline is connected to the inlet of the mud pump through a replenishment pipeline. A sight glass is installed on the mud conveying pipeline.

[0008] Furthermore, it includes two of the aforementioned bar screens, each equipped with a slag discharge auger at its slag outlet.

[0009] Furthermore, the slurry outlet of the horizontal centrifuge is equipped with a slurry discharge auger.

[0010] The second objective of this invention is to overcome the shortcomings of the existing technology and provide an efficient sludge removal method for sugar beet processing wastewater.

[0011] The second objective of this invention is achieved through the following technical solution: a highly efficient sludge removal method for sugar beet processing wastewater, comprising the following components: During the early stage of processing fresh sugar beets, the organic matter content of the wastewater is relatively low. After pretreatment in the radial flow sedimentation tank, the wastewater enters two sedimentation tanks, A and B, which can be connected in series and can be switched to operate in parallel, for static sedimentation. The wastewater stays in the tank for 24±2 hours. After the tank is full, the upper clarified liquid with turbidity ≤50NTU and SS ≤100mg / L is discharged into the oxidation pond through the weir. After the oxidation pond reaches the standard level, it is transported to the wastewater treatment plant for further treatment. In the later stages of production, the processing volume of rotten and frozen beets increases, leading to a significant rise in soluble organic matter in the wastewater and increased water viscosity. At this point, sedimentation tanks A and B are adjusted to operate in parallel. Wastewater pretreated by the radial flow sedimentation tank first enters sedimentation tank A for sedimentation, while sedimentation tank B remains inactive. When the turbidity of the supernatant flowing out of the effluent weir of sedimentation tank A exceeds the standard, sedimentation tank B is immediately activated to receive the wastewater pretreated by the radial flow sedimentation tank and perform segmented sludge removal treatment on the wastewater in sedimentation tank A. After the segmented sludge removal treatment in sedimentation tank A is completed, if the turbidity of the supernatant flowing out of the effluent weir of sedimentation tank B exceeds the standard, segmented sludge removal treatment is performed on the wastewater in sedimentation tank B again, and sedimentation tank A is activated again to receive the wastewater pretreated by the radial flow sedimentation tank. Sedimentation tanks A and B operate alternately in a cyclical manner. When performing segmented sludge removal treatment on wastewater in sedimentation tank A or sedimentation tank B, the water in sedimentation tank A or sedimentation tank B is in a stratified state, with high organic matter wastewater in the middle and upper part and compacted sludge occupying 1 / 4 of the tank volume at the bottom. First, the high organic matter wastewater in the middle and upper part of the tank is extracted for deep sludge removal treatment. When only the compacted sedimented sludge at the bottom remains in the tank, an excavator is used to dredge and transport it off the tank, so as to achieve efficient separation of impurities in the wastewater. During deep sludge desludge treatment, high-organic-matter wastewater first enters a bar screen to remove insoluble organic impurities such as beet peels and large particles. These impurities are then transported to a sand and slag pond for centralized disposal via a slag discharge auger. The filtered wastewater flows into a collection tank and is then pumped to a settling tank. A first dosing pump simultaneously pumps coagulant from the coagulant aid tank into the settling tank, every 300m³. 3 30-50 kg of flocculant is added to the wastewater; simultaneously, the flocculant in the flocculant tank is added to the settling tank by the second dosing pump. The CPAM flocculant has a molecular weight of 12 million and a dosage of 0.5‰, which is used to synergistically coagulate the wastewater. Under the action of the agent, the soluble organic matter in the wastewater quickly forms flocculent precipitates. The treated upper clear liquid is discharged into the oxidation pond, and the lower flocculent slurry is sent to the sediment guide through the bottom outlet of the settling tank. Then, it is transported by the slurry pump and slurry conveying pipeline to the horizontal centrifuge for deep dewatering. After centrifugation and dewatering, the sludge moisture content is greatly reduced, forming dry sludge, which is then transported to the sludge pond by a sludge discharge auger for loading and off-site transportation; the wastewater separated by centrifugation is returned to the oxidation pond, realizing a closed-loop treatment process.

[0012] Furthermore, a sight glass is installed on the mud conveying pipeline to monitor the mud flocculation effect in real time. If the flocculation effect does not meet the standard, 1-5 ppm of flocculant solution is added to the pipeline at the front end of the mud pump for online adjustment.

[0013] This invention utilizes a series and parallel switching operation of sedimentation tanks A and B, combined with a bar screen, settling tank, and horizontal centrifuge to form a sludge treatment system. This system effectively achieves efficient sludge removal from sugar beet production wastewater, significantly reducing the load on subsequent wastewater treatment, minimizing chemical consumption, while simultaneously improving sludge dewatering efficiency and mitigating environmental risks during dredging and transportation.

[0014] The beneficial effects of this invention are: 1. This invention effectively improves the efficiency of mud-water separation, removing over 80% of organic matter, reducing turbidity by over 70%, and reducing impurities in wastewater treatment plant influent by over 70%. 2. This invention avoids the site pollution and mud leakage risks caused by traditional excavator dredging; the dried mud cake can be utilized as a resource (e.g., composting or landfilling), meeting environmental protection requirements. 3. The two small sedimentation tanks operate alternately, resulting in high equipment utilization of the system. 4. This invention saves on chemical costs, reduces mud transportation costs, and significantly lowers overall operating costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the present invention.

[0016] In the diagram: 1. Bar screen; 2. Coagulant tank; 3. First dosing pump; 4. Rotor flow meter; 5. Flocculant tank; 6. Second dosing pump; 7. Settler; 8. Sediment guide; 9. Slurry pump; 10. Sight glass; 11. Horizontal centrifuge; 12. Sludge discharge auger; 13. Water collection tank; 14. Sewage pump; 15. Slag discharge auger; 16-Radial flow sedimentation tank; 17-Sedimentation tank A; 18-Sedimentation tank B; 19-Oxidation pond; 20-First three-way valve; 21-Second three-way valve; 22-Third three-way valve. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings.

[0018] like Figure 1As shown, this invention relates to a high-efficiency sludge removal system for sugar beet processing wastewater, including a radial flow sedimentation tank 16, an oxidation pond 19, an A sedimentation tank 17 located below the wastewater outlet of the radial flow sedimentation tank 16, a B sedimentation tank 18 located below the A sedimentation tank 17, a bar screen 1 located below the B sedimentation tank 18, a water collection tank 13 located below the bar screen 1, an inverted cone-shaped settling device 7, a sludge guide 8, and a horizontal centrifuge 11. The oxidation pond 19 is located below the B sedimentation tank 18. The wastewater outlet of the radial flow sedimentation tank 16 is connected to the top inlet of the A sedimentation tank 17 and the top inlet of the B sedimentation tank 18 via a first three-way valve 20 and pipelines. The middle outlet of 7 is connected to the inlet of bar screen 1 and the top inlet of sedimentation tank 18 via a second three-way valve 21 and a pipeline. The middle outlet of sedimentation tank 18 is connected to the inlet of bar screen 1 and the inlet of oxidation pond 19 via a third three-way valve 22 and a pipeline. The water collection tank 13 is located below bar screen 1. The sewage outlet of bar screen 1 is connected to the inlet of water collection tank 13 via a pipeline. The outlet of water collection tank 13 is connected to the inlet of sedimentation tank 7 via sewage pump 14 and a pipeline. The sludge guide 8 is located directly below the lower outlet of sedimentation tank 7. The outlet of sludge guide 8 is connected to the inlet of horizontal centrifuge 11 via sludge pump 9 and sludge conveying pipeline.

[0019] The present invention also includes a coagulant aid tank 2 and a flocculant tank 5. The coagulant aid tank 2 is connected to the inlet of the settling tank 7 through a first dosing pump 3, a first dosing branch pipe, and a main dosing pipeline. The flocculant tank 5 is connected to the inlet of the settling tank 7 through a second dosing pump 6, a second dosing branch pipe, and a main dosing pipeline. A rotor flow meter 4 is installed on the main dosing pipeline. The main dosing pipeline is connected to the inlet of the mud pump 9 through a replenishment pipeline. A sight glass tube 10 is installed on the mud conveying pipeline.

[0020] This invention includes two bar screens 1, each with a slag discharge auger 15 at its slag outlet. A horizontal centrifuge 11 has a sludge discharge auger 12 at its slurry outlet.

[0021] This invention also relates to an efficient sludge removal method for sugar beet processing wastewater, comprising the following: During the early stages of production (September-November) when processing fresh sugar beets, the organic matter content of the wastewater is relatively low, such as... Figure 1 As shown, the wastewater pretreated by the radial flow sedimentation tank 16 enters two sedimentation tanks, A 17 and B 18, which can be connected in series and operated in parallel, for static sedimentation. Each sedimentation tank 17 and B 18 has a volume of 4000 m³ and dimensions of 40 m × 20 m × 5 m. Each tank is equipped with an adjustable weir with an opening range of 0-100 mm and an ultrasonic sludge level gauge with an accuracy of ±5 cm. The wastewater stays in the tank for 24 ± 2 hours. After the tank is full, the upper clarified liquid with turbidity ≤50 NTU and SS ≤100 mg / L is discharged into the oxidation pond 19 through the weir. After the liquid level in the oxidation pond 19 reaches the standard, it is transported to the wastewater treatment plant for further treatment. During the later stages of production (December to March of the following year, when the cold winter in the north leads to an increase in the processing of frozen and thawed vegetables), the amount of rotten and frozen beets processed increases, resulting in a significant rise in soluble organic matter in the wastewater and increased water viscosity. Conventional sedimentation treatment is no longer sufficient to meet subsequent treatment requirements. In this invention, sedimentation tanks A (17) and B (18) are adjusted to operate in parallel. Wastewater pretreated by radial flow sedimentation tank 16 first enters sedimentation tank A (17) for sedimentation, while sedimentation tank B (18) remains inactive. When the turbidity of the supernatant flowing out of the effluent weir of sedimentation tank A (17) exceeds the standard (large... When the turbidity of the wastewater in sedimentation tank B exceeds 6000 NTU, sedimentation tank B 18 is immediately activated to receive the wastewater after pretreatment in the radial flow sedimentation tank. Sedimentation tank A 17 is then treated in stages to remove sludge. After the sludge removal is completed in sedimentation tank A 17, if the turbidity of the supernatant flowing out of the effluent weir of sedimentation tank B 18 exceeds the standard (greater than 6000 NTU), sedimentation tank B 18 is treated in stages to remove sludge. Sedimentation tank A 17 is then activated to receive the wastewater after pretreatment in the radial flow sedimentation tank 16. Sedimentation tank A 17 and sedimentation tank B 18 are operated alternately in a cycle. When performing segmented sludge removal treatment on wastewater in sedimentation tank A 17 or sedimentation tank B 18, the water in sedimentation tank A 17 or sedimentation tank B 18 exhibits a stratified state, with high organic matter wastewater in the upper and middle parts and compacted sludge occupying 1 / 4 of the tank volume at the bottom. Traditional sludge removal methods easily disturb the sludge, leading to mud-water mixing and a surge in sludge moisture content. This invention adopts a stratified treatment method, first extracting the high organic matter wastewater in the upper and middle parts of the tank for deep sludge removal treatment, and then using an excavator to remove and transport the sludge after only the compacted sedimented sludge at the bottom of the tank, thus achieving efficient separation of impurities in the wastewater. During the deep desludge treatment, the high organic matter wastewater first enters the bar screen 1 to screen out insoluble organic impurities such as beet peels and large particles of residue. These impurities are then transported to the sand and slag pond for centralized disposal via the slag discharge auger 15. The filtered wastewater flows into the water collection tank 13 and is then pumped to the sedimentation tank 7 by the wastewater pump 14. The first dosing pump 3 pumps the coagulant aid from the coagulant aid tank 2 into the settling tank 7, every 300m³. 3 30-50 kg of flocculant is added to the wastewater; the flocculant in flocculant tank 5 is added to the settling tank 7 by the second dosing pump 6; the amount of coagulant and flocculant added is controlled by the first dosing pump 3 and the second dosing pump 6 according to the flow rates of coagulant and flocculant in the rotor flowmeter 4; the CPAM flocculant has a molecular weight of 12 million and a dosage of 0.5‰, and is used to synergistically coagulate the wastewater; under the action of the agent, the soluble organic matter in the wastewater quickly forms flocculent precipitate, the treated upper clear liquid is discharged into the oxidation pond, and the lower flocculent slurry is sent to the sediment guide 8 through the bottom outlet of the settling tank 7, and then transported to the horizontal centrifuge 11 for deep dewatering by the slurry pump 9 and slurry conveying pipeline; The horizontal centrifuge 11 is a solid-liquid two-phase separation horizontal spiral centrifuge, which can achieve continuous and stable operation for 24 hours. After centrifugation and dewatering, the water content of the sludge is greatly reduced, forming dry sludge, which is transported to the sludge tank for loading and transportation through the sludge discharge auger 12. The wastewater separated by centrifugation is returned to the oxidation pond 19 to realize the closed loop of the treatment process.

[0022] The mud conveying pipeline is equipped with a sight glass tube 10 to observe the mud flocculation effect in real time. If the flocculation effect is not up to standard, 1-5 ppm of flocculant solution is added to the pipeline at the front end of the mud pump 9 for online adjustment.

[0023] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A high-efficiency sludge removal system for sugar beet processing wastewater, comprising a radial flow sedimentation tank and an oxidation pond, characterized in that: It also includes sedimentation tank A located below the wastewater outlet of the radial flow sedimentation tank, sedimentation tank B located below sedimentation tank A, a bar screen located below sedimentation tank B, a collection tank located below the bar screen, an inverted cone-shaped settling device, a sediment guide, and a horizontal centrifuge. The oxidation pond is located below sedimentation tank B. The wastewater outlet of the radial flow sedimentation tank is connected to the top inlet of sedimentation tank A and the top inlet of sedimentation tank B via a first three-way valve and pipeline. The middle outlet of sedimentation tank A is connected to the bar screen via a second three-way valve and pipeline. The inlet of the screen machine is connected to the top inlet of the B sedimentation tank. The middle outlet of the B sedimentation tank is connected to the inlet of the screen machine and the inlet of the oxidation pond through a third three-way valve and pipeline. The sewage outlet of the screen machine is connected to the inlet of the water collection tank through pipeline. The outlet of the water collection tank is connected to the inlet of the sedimentation unit through a sewage pump and pipeline. The sludge guide is located directly below the lower outlet of the sedimentation unit. The outlet of the sludge guide is connected to the inlet of the horizontal centrifuge through a sludge pump and sludge conveying pipeline.

2. The high-efficiency sludge removal system for sugar beet processing wastewater according to claim 1, characterized in that: It also includes a coagulant aid tank and a flocculant tank. The coagulant aid tank is connected to the inlet of the settling tank through a first dosing pump, a first dosing branch pipe, and a main dosing pipeline. The flocculant tank is connected to the inlet of the settling tank through a second dosing pump, a second dosing branch pipe, and the main dosing pipeline. A rotor flow meter is installed on the main dosing pipeline. The main dosing pipeline is connected to the inlet of the mud pump through a replenishment pipeline. A sight glass is installed on the mud conveying pipeline.

3. The high-efficiency sludge removal system for sugar beet processing wastewater according to claim 1, characterized in that: It includes two bar screens, and the slag outlet of the bar screen is equipped with a slag discharge auger.

4. The high-efficiency sludge removal system for sugar beet processing wastewater according to claim 1, characterized in that: The horizontal centrifuge is equipped with a mud discharge auger at the mud outlet.

5. A highly efficient sludge removal method for sugar beet processing wastewater, characterized in that... Includes the following: The efficient sludge removal method for beet sugar production wastewater adopts the efficient sludge removal system for beet sugar production wastewater as described in claim 1; During the early stage of processing fresh sugar beets, the organic matter content of the wastewater is relatively low. After pretreatment in the radial flow sedimentation tank, the wastewater enters two sedimentation tanks, A and B, which can be connected in series and can be switched to operate in parallel, for static sedimentation. The wastewater stays in the tank for 24±2 hours. After the tank is full, the upper clarified liquid with turbidity ≤50NTU and SS ≤100mg / L is discharged into the oxidation pond through the weir. After the oxidation pond reaches the standard level, it is transported to the wastewater treatment plant for further treatment. In the later stages of production, the processing volume of rotten and frozen beets increases, leading to a significant rise in soluble organic matter in the wastewater and increased water viscosity. At this point, sedimentation tanks A and B are adjusted to operate in parallel. Wastewater pretreated by the radial flow sedimentation tank first enters sedimentation tank A for sedimentation, while sedimentation tank B remains inactive. When the turbidity of the supernatant flowing out of the effluent weir of sedimentation tank A exceeds the standard, sedimentation tank B is immediately activated to receive the wastewater pretreated by the radial flow sedimentation tank and perform segmented sludge removal treatment on the wastewater in sedimentation tank A. After the segmented sludge removal treatment in sedimentation tank A is completed, if the turbidity of the supernatant flowing out of the effluent weir of sedimentation tank B exceeds the standard, segmented sludge removal treatment is performed on the wastewater in sedimentation tank B again, and sedimentation tank A is activated again to receive the wastewater pretreated by the radial flow sedimentation tank. Sedimentation tanks A and B operate alternately in a cyclical manner. When performing segmented sludge removal treatment on wastewater in sedimentation tank A or sedimentation tank B, the water in sedimentation tank A or sedimentation tank B is in a stratified state, with high organic matter wastewater in the middle and upper part and compacted sludge occupying 1 / 4 of the tank volume at the bottom. First, the high organic matter wastewater in the middle and upper part of the tank is extracted for deep sludge removal treatment. When only the compacted sedimented sludge at the bottom remains in the tank, an excavator is used to dredge and transport it off the tank, so as to achieve efficient separation of impurities in the wastewater. During the deep desludge treatment, the high organic matter wastewater first enters the bar screen to remove insoluble organic impurities such as beet peels and large particles of residue. These impurities are then transported to the sand and slag pond for centralized disposal via a slag discharge auger. The filtered wastewater flows into the collection tank and is then pumped to the settling tank by a wastewater pump. The first dosing pump synchronously pumps the coagulant aid from the tank into the settling tank, every 300m³. 3 30-50 kg of flocculant is added to the wastewater; simultaneously, the flocculant in the flocculant tank is added to the settling tank by the second dosing pump. The CPAM flocculant has a molecular weight of 12 million and a dosage of 0.5‰, which is used to synergistically coagulate the wastewater. Under the action of the agent, the soluble organic matter in the wastewater quickly forms flocculent precipitates. The treated upper clear liquid is discharged into the oxidation pond, and the lower flocculent slurry is sent to the sediment guide through the bottom outlet of the settling tank. Then, it is transported by the slurry pump and slurry conveying pipeline to the horizontal centrifuge for deep dewatering. After centrifugation and dewatering, the sludge moisture content is greatly reduced, forming dry sludge, which is then transported to the sludge pond by a sludge discharge auger for loading and off-site transportation; the wastewater separated by centrifugation is returned to the oxidation pond, realizing a closed-loop treatment process.

6. The efficient sludge removal method for sugar beet processing wastewater according to claim 5, characterized in that: The mud conveying pipeline is equipped with a sight glass tube to monitor the mud flocculation effect in real time. If the flocculation effect does not meet the standard, 1-5 ppm of flocculant solution is added to the pipeline at the front end of the mud pump for online adjustment.

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