A high-efficiency precipitation system without adding chemicals and reflux

Abstract

The utility model relates to a kind of high-efficiency sedimentation system without dosing and backflow, including the biochemical pool, secondary sedimentation tank, high-efficiency sedimentation tank connected in turn, sludge generated by secondary sedimentation tank, high-efficiency sedimentation tank is discharged into sludge tank, the effluent sludge concentration of secondary sedimentation tank flow to high-efficiency sedimentation tank is 2% or more, coagulation tank and flocculator are not set between secondary sedimentation tank and high-efficiency sedimentation tank, and high-efficiency sedimentation tank does not include sludge backflow pump and sludge backflow pipeline.The utility model is optimized and reconstructed to traditional sewage treatment process, significantly reduces system energy consumption and operating cost under the premise of guaranteeing effluent quality, realizes the stable operation of high-efficiency sedimentation tank under the condition of without dosing and without sludge backflow by improving the key technical means of secondary sedimentation tank effluent sludge concentration, not only simplifies process flow, reduces equipment configuration and energy consumption, but also significantly reduces investment and operating cost, while giving consideration to good sedimentation performance and effluent quality stability, with higher application and promotion value.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology in environmental engineering, and in particular to a high-efficiency sedimentation system that does not require chemical addition or reflux. Background Technology

[0002] With increasingly stringent national standards for municipal wastewater treatment and discharge, particularly the more detailed restrictions on indicators such as suspended solids (SS), wastewater treatment plants built using traditional processes often struggle to consistently meet the latest discharge requirements. In urban wastewater treatment processes, suspended solids are a significant physical pollutant affecting water purification efficiency, typically removed through gravity settling, filtration, or flocculation. Currently, common processes include activated sludge processes, oxidation ditch processes, and sequencing batch reactors (SBRs). These processes effectively reduce organic matter content and some settleable particles; however, after secondary sedimentation, the sludge concentration is usually significantly reduced, and residual fine suspended solids remain difficult to completely remove through gravity settling.

[0003] To improve solid-liquid separation efficiency after the secondary sedimentation tank, high-efficiency sedimentation tanks have been introduced into existing technologies. These devices are often installed after the secondary sedimentation tank and enhance the sedimentation effect through improvements such as inclined plates and horizontal flow sedimentation. Inclined plate settlers, by setting inclined plates, allow suspended matter to have a longer sedimentation path during flow between the plates, thereby improving particle sedimentation efficiency, and have been widely adopted in some wastewater treatment plants.

[0004] However, traditional high-efficiency sedimentation processes have significant limitations. Since the secondary sedimentation tank removes a large number of settling coarse particles, the sludge particles entering the high-efficiency sedimentation tank are mainly fine suspended solids with a diameter of less than 0.1 mm. These particles settle slowly, have a large specific surface area, and are not easily separated by gravity. To improve the high-efficiency sedimentation effect, existing technologies often employ sludge recirculation, which involves returning the settled sludge to the inlet of the high-efficiency sedimentation tank to increase the sludge concentration and the number of flocs, thereby utilizing the flocculation effect of the sludge itself on fine particles to enhance sedimentation. However, to ensure the sedimentation effect, the sludge concentration in the sedimentation zone must be controlled above 2%, and the sludge recirculation ratio is typically adjusted within the range of 10-30% to ensure sufficient activated sludge participates in the sedimentation process. This high-ratio sludge recirculation results in high energy consumption for system operation, increasing power consumption and equipment maintenance costs.

[0005] To promote the aggregation of fine particles into larger, more easily settled aggregates (flocculations), existing technologies often include a coagulation or flocculation tank before the high-efficiency sedimentation tank. Chemical coagulants (such as polyaluminum chloride, ferric salt flocculants, etc.) or organic polymeric flocculants are added to enhance the aggregation and sedimentation of fine suspended solids in the water. While this physicochemical method combined with gravity sedimentation is effective in removing suspended solids, it also introduces new problems. The dosage of chemical agents is often large, significantly increasing operating costs and occupying land resources at the treatment site. Furthermore, the use of agents may lead to secondary pollution problems; for example, excessive flocculants can inhibit downstream biological treatment units. Simultaneously, the significantly increased amount of flocculent sludge also exacerbates sludge disposal pressures. Utility Model Content

[0006] The technical problem to be solved by this utility model is to overcome the shortcomings of the existing technology and provide a high-efficiency precipitation system that does not require the addition of chemicals or reflux.

[0007] This utility model is achieved through the following technical solution: A high-efficiency sedimentation system that requires no chemical addition or reflux includes a biological treatment tank, a secondary sedimentation tank, and a high-efficiency sedimentation tank connected in sequence. The sludge produced by the secondary sedimentation tank and the high-efficiency sedimentation tank is discharged into a sludge tank. The effluent sludge concentration flowing from the secondary sedimentation tank to the high-efficiency sedimentation tank is above 2%. No coagulation tank or flocculation tank is set between the secondary sedimentation tank and the high-efficiency sedimentation tank. The high-efficiency sedimentation tank does not include a sludge reflux pump or sludge reflux pipeline.

[0008] According to the above technical solution, preferably, the sludge settling ratio of the secondary sedimentation tank is 20-40%, and the sludge particle diameter is above 0.5mm.

[0009] According to the above technical solution, preferably, the high-efficiency sedimentation tank includes an inlet pipe, a sludge scraper, an inclined tube assembly, an overflow trough, and a sludge discharge pipe. The inlet pipe is located at the lower side of the high-efficiency sedimentation tank, the sludge discharge pipe is located at the bottom of the high-efficiency sedimentation tank, the inclined tube assembly is located in the upper middle part of the high-efficiency sedimentation tank, and the overflow trough is located above the inclined tube assembly.

[0010] According to the above technical solution, preferably, the inclined tube assembly includes an inclined tube and an inclined tube support for mounting the inclined tube.

[0011] According to the above technical solution, preferably, the high-efficiency sedimentation tank further includes a guide wall, which is set close to the water inlet pipe, to make the sludge entering the high-efficiency sedimentation tank flow in an inverted U-shaped structure and flow towards the sludge scraper.

[0012] The beneficial effects of this utility model are: This invention optimizes and reconstructs traditional wastewater treatment processes, significantly reducing system energy consumption and operating costs while ensuring effluent quality. By increasing the sludge concentration in the secondary sedimentation tank, a key technological approach, it achieves stable operation of the high-efficiency sedimentation tank without the need for chemical dosing or sludge recirculation. This not only simplifies the process flow and reduces equipment configuration and energy consumption, but also significantly lowers investment and operating costs. Simultaneously, it maintains good sedimentation performance and effluent quality stability, demonstrating significant technological advancement and broad engineering application value. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the system connection of this utility model.

[0014] Figure 2 This is a schematic diagram of system connections in the prior art.

[0015] Figure 3 This is a schematic diagram of the main structure of the high-efficiency sedimentation tank in this utility model.

[0016] Figure 4 This is a schematic diagram of the main structure of a high-efficiency sedimentation tank in existing technology.

[0017] Figure 3 In the middle: 1. Inlet pipe; 2. Guide wall; 3. Inclined pipe; 4. Inclined pipe support; 5. Overflow trough; 6. Sludge discharge pipe; 7. Sludge scraper. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and preferred embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0019] In the description of the utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.

[0020] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] As shown in the figure, this utility model includes a biological treatment tank, a secondary sedimentation tank, and a high-efficiency sedimentation tank connected in sequence. The sludge produced by the secondary sedimentation tank and the high-efficiency sedimentation tank is discharged into a sludge tank. By reducing the floor space occupied by the secondary sedimentation tank, its area loading is reduced from 0.5 to 1 m². 3 / (m 2 •h) increased to 1.5m 3 / (m 2 ·h) and above, The effluent sludge concentration flowing from the secondary sedimentation tank to the high-efficiency sedimentation tank reaches more than 2%. Under this condition, the sludge concentration entering the high-efficiency sedimentation tank meets the basic requirements for high-efficiency sedimentation. This solves the problem in the existing technology that requires sludge return due to the low effluent sludge concentration in the secondary sedimentation tank. As a result, the high-efficiency sedimentation tank can still maintain a good settling effect without the need to install sludge return pumps and sludge return pipelines.

[0022] Meanwhile, the sludge in the secondary sedimentation tank is activated sludge, with a sludge settling ratio typically between 20-40%, exhibiting good settling properties. Due to the increased sludge concentration, the probability of collision and aggregation between sludge particles significantly increases, and the particle diameter also increases accordingly to over 0.5 mm. Larger sludge particles not only settle faster but also possess better coagulation and flocculation properties, thus enabling effective capture and settling of fine suspended solids without the addition of coagulants and flocculants. This technical effect allows the invention to completely eliminate the conventional coagulation and flocculation tanks installed at the front end of the high-efficiency sedimentation tank, avoiding the construction and operation of a chemical dosing system. By eliminating the addition of coagulants and flocculants, this application significantly reduces engineering investment while effectively reducing chemical consumption costs during operation, lowering the long-term operating cost of the system. Furthermore, since no external chemical agents are introduced, the amount of chemical sludge generated by the system is significantly reduced, consequently lowering the pressure on subsequent sludge treatment and disposal, which is conducive to achieving the energy-saving, emission-reduction, and green operation goals of the wastewater treatment system.

[0023] In terms of the structural design of the high-efficiency sedimentation tank, the high-efficiency sedimentation tank includes an inlet pipe 1, a sludge scraper 7, an inclined tube assembly, an overflow trough 5, and a sludge discharge pipe 6. The inclined tube assembly includes an inclined tube 3 and an inclined tube support 4 for installing the inclined tube 3. The inlet pipe 1 is located at the lower side of the high-efficiency sedimentation tank, the sludge discharge pipe 6 is located at the bottom of the high-efficiency sedimentation tank, the inclined tube assembly is located in the upper middle part of the high-efficiency sedimentation tank, and the overflow trough 5 is located above the inclined tube assembly. It also includes a guide wall 2, located near the inlet pipe 1, used to direct the flow of sludge entering the high-efficiency sedimentation tank into an inverted U-shaped structure, leading it towards the sludge scraper 7.

[0024] By rationally configuring components such as the inlet pipe 1, guide wall 2, inclined tube assembly, overflow trough 5, and scraper 7, a stable and orderly hydraulic flow pattern of sludge is formed within the sedimentation tank. The inlet pipe 1 is located on the lower side of the high-efficiency sedimentation tank, with the guide wall 2 nearby. This guides the incoming water into the sedimentation tank, creating an inverted U-shaped flow structure. This avoids direct impact of the incoming water on the sedimentation area and extends the effective residence time of the sludge within the sedimentation tank, facilitating the downward settling of sludge particles and their concentration at the bottom. The inclined tubes 3 and 4 form an efficient shallow sedimentation structure, further shortening the settling distance of the sludge particles and improving sedimentation efficiency. Since the sludge entering the inclined tube 3 area already possesses a large particle size and good settling performance, the inclined tube assembly maintains a stable solid-liquid separation effect even under high surface loading conditions, thus ensuring stable compliance of the effluent quality. The cooperation between the sludge scraper 7 and the sludge discharge pipe 6 at the bottom of the pool enables the sludge that has settled to the bottom of the pool to be discharged into the sludge pool in a timely and continuous manner, avoiding the phenomenon of sludge floating or resuspending due to prolonged retention in the pool, and further enhancing the reliability and continuity of the system operation.

[0025] In summary, compared with existing high-efficiency sedimentation processes that require coagulation and flocculation dosing units and rely on sludge recirculation, the high-efficiency sedimentation system proposed in this application, which eliminates the need for dosing and recirculation, achieves significant technical benefits and practical advantages in terms of process flow, operating energy consumption, treatment costs, and system stability. This application achieves stable operation of the high-efficiency sedimentation tank without the need for dosing or sludge recirculation by increasing the sludge concentration in the secondary sedimentation tank effluent, a key technical means. This not only simplifies the process flow and reduces equipment configuration and energy consumption but also significantly lowers investment and operating costs. Simultaneously, it maintains good sedimentation performance and effluent quality stability, demonstrating significant technological advancement and broad engineering application value.

[0026] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A highly efficient precipitation system that requires no chemical addition or reflux, characterized in that, It includes a biological treatment tank, a secondary sedimentation tank, and a high-efficiency sedimentation tank connected in sequence. The sludge produced by the secondary sedimentation tank and the high-efficiency sedimentation tank is discharged into a sludge tank. The effluent sludge concentration from the secondary sedimentation tank to the high-efficiency sedimentation tank is above 2%. No coagulation tank or flocculation tank is set between the secondary sedimentation tank and the high-efficiency sedimentation tank. The high-efficiency sedimentation tank does not include a sludge return pump or sludge return pipeline.

2. The high-efficiency precipitation system without chemical addition and reflux as described in claim 1, characterized in that, The sludge settling ratio in the secondary sedimentation tank is 20-40%, and the sludge particle diameter is above 0.5 mm.

3. The high-efficiency precipitation system without chemical addition and reflux as described in claim 1 or 2, characterized in that, The high-efficiency sedimentation tank includes an inlet pipe (1), a sludge scraper (7), an inclined tube assembly, an overflow trough (5), and a sludge discharge pipe (6). The inlet pipe (1) is located on the lower side of the high-efficiency sedimentation tank, the sludge discharge pipe (6) is located at the bottom of the high-efficiency sedimentation tank, the inclined tube assembly is located in the upper middle part of the high-efficiency sedimentation tank, and the overflow trough (5) is located above the inclined tube assembly.

4. The high-efficiency precipitation system without chemical addition and reflux as described in claim 3, characterized in that, The inclined tube assembly includes an inclined tube (3) and an inclined tube support (4) for mounting the inclined tube (3).

5. The high-efficiency precipitation system without the need for chemical addition and reflux as described in claim 3, characterized in that, The high-efficiency sedimentation tank also includes a guide wall (2), which is set near the inlet pipe (1) to make the sludge entering the high-efficiency sedimentation tank flow in an inverted U-shaped structure and flow to the sludge scraper (7).

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