An activated sludge recovery sedimentation tank for a sewage treatment plant

Abstract

The present invention relates to the technical field of sewage treatment, and particularly to an activated sludge recovery sedimentation tank for a sewage treatment plant. The left side of the tank cavity is communicated with the water outlet of the biological reaction tank. A drainage structure is provided on the right side of the tank cavity. In the middle of the tank cavity, there is a scum collection channel arranged at an interval above and below the bottom wall of the tank cavity. The scum collection channel includes a left side wall and a right side wall arranged at an interval from left to right. The upper end surface of the left side wall is below the water surface. When the scum on the top of the tank cavity flows from left to right, it crosses the left side wall and flows into the scum collection channel. The upper end surface of the right side wall is higher than the water surface and can prevent the scum flowing into the scum collection channel from flowing to the drainage structure. The purified sewage in the tank cavity flows into the right side of the tank cavity through the interval between the scum collection channel and the bottom wall of the tank cavity and enters the drainage structure. Therefore, the activated sludge recovery sedimentation tank for the sewage treatment plant of the present invention can treat and recover the scum floating on the water surface, avoiding the influence of the outflow of activated sludge and suspended substances on the effluent quality.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly to an activated sludge recovery sedimentation tank for a sewage treatment plant. Background Art

[0002] Sewage treatment plants in cities generally adopt the sewage biological treatment technology with activated sludge as the main body. Activated sludge is a floc containing various microbial populations propagated in a biological reaction tank. By taking a series of artificially enhanced and controlled technical measures, the physiological functions of the microorganisms in the activated sludge to oxidize and decompose organic pollutants are fully exerted to purify the sewage. To ensure the biological decomposition effect, the activated sludge needs to be kept in a suspended state in the biological reaction tank, so that the activated sludge is fully mixed with the sewage. After the sewage is purified by the biological reaction tank, it flows out of the biological reaction tank into the activated sludge sedimentation tank. The activated sludge sedimentation tank is arranged behind the biological reaction tank and is used to remove the activated sludge in the water. On the one hand, the activated sludge is recycled back to the biological reaction tank to maintain the recycling of the activated sludge; on the other hand, the activated sludge is separated from the sewage decomposed by microorganisms, so that the effluent of the sewage treatment plant meets the corresponding effluent standard requirements.

[0003] Activated sludge sedimentation tanks can be divided into horizontal flow sedimentation tanks, radial flow sedimentation tanks and vertical flow sedimentation tanks according to the different directions of the water flow in the tank. The horizontal flow sedimentation tank is a sedimentation tank type with a long history. Because it has the advantages of simple structure, low cost, convenient operation and maintenance, strong adaptability to changes in the quality and quantity of raw water, low chemical consumption and energy consumption, and being convenient for recycling the settled activated sludge, it is widely used in large and medium-sized water plants.

[0004] As Figure 1 shown in the structural schematic diagram of the existing horizontal flow sedimentation tank, the left side of the horizontal flow sedimentation tank is provided with a water inlet, the upper right side is provided with a water outlet, and the bottom is provided with a sludge scraping device for collecting the activated sludge deposited at the bottom. However, some suspended substances with relatively small density and low sedimentation rate in the horizontal flow sedimentation tank and some activated sludge gradually float to the water surface to form scum after adhering to the gas generated by anaerobic digestion. The current horizontal flow sedimentation tank is only provided with a sludge scraping device for collecting the activated sludge deposited at the bottom of the tank, and does not treat the activated sludge floating to the water surface, resulting in the deterioration of the effluent quality. Summary of the Invention

[0005] The purpose of the present invention is to provide an activated sludge recovery sedimentation tank for a sewage treatment plant.

[0006] The activated sludge recovery sedimentation tank for a sewage treatment plant of the present invention includes a tank body having a tank cavity. The left side of the tank cavity is communicated with the water outlet of a biological reaction tank. A drainage structure is provided on the right side of the tank cavity. A scum collection channel is arranged in the middle of the tank cavity and is arranged at an interval from the bottom wall of the tank cavity up and down. The scum collection channel includes a left side wall and a right side wall arranged at an interval left and right. The upper end surface of the left side wall is below the water surface, and the upper end surface of the right side wall is higher than the water surface.

[0007] As a preferred solution, a horizontally arranged partition board is provided in the tank cavity. The partition board is located between the scum collection channel and the bottom wall of the tank cavity, and is arranged at an interval left and right from the left side wall of the tank cavity. The partition board divides the right part of the tank cavity into a scum collection layer and a sediment collection layer. The scum collection layer is located above the sediment collection layer.

[0008] As a preferred solution, the scum collection channel is arranged on the right side of the scum collection layer. A diversion channel is provided on the left side of the scum collection layer for guiding the water in the tank cavity on the left side of the partition board into the scum collection layer. The water outlet of the diversion channel is arranged upward.

[0009] As a preferred solution, a water distribution board is fixed at the water outlet of the diversion channel. The water distribution board is provided with a plurality of vertically arranged water permeable holes at intervals.

[0010] As a preferred solution, an underwater aeration or gas release device is provided on the left side of the water inlet of the diversion channel.

[0011] As a preferred solution, a filter plate is provided in the scum collection layer and is arranged at an interval from the partition board up and down. One end of the filter plate is fixedly connected to the bottom of the outer wall of the scum collection channel, and the other end of the filter plate extends horizontally to the left and is fixedly connected to the outer wall of the diversion channel.

[0012] As a preferred solution, the activated sludge recovery sedimentation tank for the sewage treatment plant includes a sludge suction device. The sludge suction port of the sludge suction device is arranged above the filter plate.

[0013] As a preferred solution, a sludge scraping device is provided at the bottom of the sediment collection layer.

[0014] As a preferred solution, a plate-shaped water distributor is provided on the left side of the tank cavity. The plate-shaped water distributor is communicated with the water outlet of the biological reaction tank. The plate-shaped water distributor is provided with a plurality of water outlet holes at intervals up and down, and each water outlet hole is arranged horizontally to the right.

[0015] As a preferred solution, a water collection ditch extending in the front-back direction is provided in the upper right part of the scum collection layer. The right side wall of the tank body forms the right ditch wall of the water collection ditch. The top surface of the left side wall of the water collection ditch is lower than the top surface of the left side wall.

[0016] The drainage structure includes a second drainage outlet and a first drainage outlet communicating with the catch drain, and the second drainage outlet is arranged at the upper right side of the sediment collection layer.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The activated sludge recovery sedimentation tank for a sewage treatment plant of the present invention includes a tank body provided with a tank cavity. The left side of the tank cavity communicates with the water outlet of the biological reaction tank. A drainage structure is provided on the right side of the tank cavity. A scum collection channel is arranged in the middle of the tank cavity at an interval from the bottom wall of the tank cavity. The scum collection channel includes a left side wall and a right side wall arranged at an interval from left to right. The upper end surface of the left side wall is below the water surface. When the scum on the top of the tank cavity flows from left to right, it crosses the left side wall and flows into the scum collection channel. The upper end surface of the right side wall is higher than the water surface and can block the scum flowing into the scum collection channel from flowing to the drainage structure. The purified sewage in the tank cavity flows into the right side of the tank cavity through the interval between the scum collection channel and the bottom wall of the tank cavity and enters the drainage structure. Therefore, the activated sludge recovery sedimentation tank for a sewage treatment plant of the present invention can treat the scum floating on the water surface, avoid the adverse effects of the scum floating on the water surface on the quality of the treated effluent, and reduce the load of the subsequent treatment facilities. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of a conventional horizontal flow sedimentation tank;

[0020] Figure 2 is a schematic structural diagram of the activated sludge recovery sedimentation tank for a sewage treatment plant of the present invention;

[0021] Figure 3 is Figure 2 the sectional view at A-A in

[0022] Figure 4 is Figure 2 the sectional view at B-B in

[0023] In the figures, 1, tank cavity; 11, scum collection layer; 111, catch drain; 12, sediment collection layer; 13, pre-stratification area; 2, scum collection channel; 21, left side wall; 22, right side wall; 23, bottom wall; 3, partition board; 4, drainage structure; 41, first drainage outlet; 42, second drainage outlet; 5, diversion channel; 51, water distribution plate; 6, filter plate; 7, sludge suction device; 8, sludge scraping device; 9, plate-shaped water distributor. Detailed Embodiments

[0024] The following combines the drawings and embodiments to further describe in detail the specific embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. It should be understood that the terms "first", "second", etc. are used in the present invention to describe various information, but such information should not be limited to these terms, and these terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the "first" information may also be referred to as "second" information, and similarly, the "second" information may also be referred to as "first" information.

[0026] As Figures 2 to 4 shown, a preferred embodiment of the activated sludge recovery sedimentation tank for a sewage treatment plant according to the present invention includes a tank body provided with a tank cavity 1. The left side of the tank cavity 1 is communicated with the water outlet of the biological reaction tank. A drainage structure 4 is provided on the right side of the tank cavity 1. A scum collection channel 2 is provided in the middle of the tank cavity 1 and is arranged at an interval up and down with the bottom wall of the tank cavity 1. The scum collection channel 2 includes a left side wall 21 and a right side wall 22 arranged at an interval left and right. The upper end surface of the left side wall 21 is below the water surface, and the upper end surface of the right side wall 22 is higher than the water surface. The upper end surface of the left side wall 21 is below the water surface. When the scum on the top of the tank cavity 1 flows from left to right, it crosses the left side wall 21 and flows into the scum collection channel 2. The upper end surface of the right side wall 22 is higher than the water surface, which can block the scum flowing into the scum collection channel 2 from flowing to the drainage structure 4. The purified sewage in the tank cavity 1 flows into the right side of the tank cavity 1 through the interval between the scum collection channel 2 and the bottom wall of the tank cavity 1 and enters the drainage structure 4. Therefore, the activated sludge recovery sedimentation tank for a sewage treatment plant according to the present invention can recover the scum floating on the water surface, avoid the waste of activated sludge, and avoid the adverse impact of the scum floating on the water surface on the quality of the treated effluent.

[0027] Furthermore, a horizontally arranged partition plate 3 is provided in the tank cavity 1. The partition plate 3 is located between the scum collection channel 2 and the bottom wall of the tank cavity 1 and is arranged at an interval from the left side wall of the tank cavity 1. The partition plate 3 divides the right part of the tank cavity 1 into a scum collection layer 11 and a sediment collection layer 12. The scum collection layer 11 is located above the sediment collection layer 12. The partition plate 3 divides the right part of the tank cavity 1 into two relatively shallow horizontal flow sedimentation tanks. According to the "shallow tank theory", the treatment efficiency of activated sludge and the turbidity removal effect are further improved, so that the effective water depth of the tank cavity 1 can be more effectively utilized, the tank length can be shortened, and thus the floor area of the tank body is reduced. After the sewage to be treated undergoes a flocculation reaction in the left part of the tank cavity, the relatively light flocs are recovered through the scum collection layer 11; while the heavier floc particles are recovered through the sediment collection layer 12.

[0028] Specifically, the partition plate 3 is a concrete wall. The front end of the partition plate 3 is fixedly connected to the front side plate of the pool cavity 1, the rear end of the partition plate 3 is fixedly connected to the rear side wall of the pool cavity 1, and the right side of the partition plate 3 is fixedly connected to the right side wall of the pool cavity 1. The scum collection channel 2 further includes a bottom wall 23. The scum collection channel 2 is arranged on the right side of the scum collection layer 11. A diversion channel 5 for introducing the water in the pool cavity on the left side of the partition plate 3 into the scum collection layer 11 is provided on the left side of the scum collection layer 11, and the water outlet of the diversion channel 5 is arranged upward. The upward arrangement of the water outlet of the diversion channel 5 can enable the sewage discharged from the diversion channel 5 to have an upward movement speed and inertia, so that the light flocs can quickly float to the water surface, further improving the sewage treatment efficiency of the scum collection layer 11.

[0029] Further, a water distribution plate 51 is fixed at the water outlet of the diversion channel 5, and a plurality of vertically arranged water permeable holes are arranged at intervals on the water distribution plate 51. The arrangement of the water permeable holes can accelerate the water flow speed at the water outlet of the diversion channel 5, further improving the sewage treatment efficiency of the scum collection layer 11.

[0030] Further, an underwater aeration device is provided on the left side of the water inlet of the diversion channel 5. The underwater aeration device can increase the gas content of the sewage entering the diversion channel 5, further accelerating the amount of bubbles on the surface of the light flocs and increasing the floating speed of the light flocs.

[0031] In this embodiment, a filter plate 6 is arranged in the scum collection layer 11 at an upper and lower interval with the partition plate 3. One end of the filter plate 6 is fixedly connected to the bottom of the outer wall of the scum collection channel 2, and the other end of the filter plate 6 extends horizontally to the left and is fixedly connected to the outer wall of the diversion channel 5. The filter plate 6 can filter the trace sludge remaining in the scum collection layer 11 and improve the water quality of the effluent. Specifically, the diversion channel is enclosed by two concrete retaining walls arranged at left and right intervals. The lower end of the concrete retaining wall on the left is arranged at an upper and lower interval with the partition plate 3 to form the water inlet of the diversion channel 5; the lower end of the concrete retaining wall on the right is fixedly connected to the partition plate 3, and the upper end of the concrete retaining wall on the right extends upward. The other end of the filter plate 6 is fixedly connected to the concrete retaining wall on the right.

[0032] Further, the activated sludge recovery sedimentation tank for the sewage treatment plant includes a sludge suction device 7, and the sludge suction port of the sludge suction device 7 is arranged above the filter plate 6. The sludge suction device 7 can recover the activated sludge accumulated on the filter plate 6. Specifically, the sludge suction device 7 is a siphon sludge suction device.

[0033] In this embodiment, a sludge scraping device 8 is provided at the bottom of the sediment collection layer 12. The sludge scraping device 8 can recover the activated sludge precipitated at the bottom of the sediment collection layer 12, further improving the activated sludge recovery rate of this embodiment.

[0034] As Figure 2As shown in the figure, in this embodiment, the partition plate 3 divides the pool cavity 1 into three regions. The first region is the pre-stratification zone 13 located between the left side wall of the pool cavity 1 and the left side wall of the partition plate 3. The second part is the scum collection layer located directly above the partition plate 3, and the third part is the sediment collection layer located directly below the partition plate 3. After the sewage enters the pre-stratification zone 13 from the left side of the partition plate 3, it undergoes a short sedimentation in the pre-stratification zone 13. Then, the relatively clear sewage enters the scum collection layer 11 located in the upper right part of the pool cavity 1, and the suspended substances rise by attaching to tiny bubbles and are discharged to the scum collection channel 2 for removal. The relatively turbid sewage enters the sediment collection layer 12 located in the lower right part of the pool cavity 1, and the mud and water are separated through the sedimentation process. The sludge settles to the bottom of the sediment collection layer 12.

[0035] To ensure uniform water replenishment when entering the pre-stratification zone 13, a plate-shaped water distributor 9 is provided on the left side of the pool cavity 1. The plate-shaped water distributor 9 is connected to the water outlet of the biological reaction tank. The plate-shaped water distributor 9 is provided with a plurality of water outlet holes at intervals up and down, and each water outlet hole is arranged horizontally to the right.

[0036] In this embodiment, a water collecting groove 111 extending in the front-rear direction is provided in the upper right part of the scum collection layer 11. The right side wall of the pool body forms the right groove wall of the water collecting groove 111. The top surface of the left side wall of the water collecting groove 111 is lower than the top surface of the left side wall 21 of the scum collection channel 2. The drainage structure 4 includes a second drainage port 42 and a first drainage port 41 communicated with the water collecting groove 111. The second drainage port 42 is arranged in the upper right part of the sediment collection layer 12. The separate water outlet of the scum collection layer 11 and the sediment collection layer 12 of the sedimentation tank not only reduces the water outlet load of the scum collection layer 11 and the sediment collection layer 12, but also avoids the interference of the water outlet of only the sediment collection layer 12 on the scum collection layer 11, and the water outlet quality is more stable. In this embodiment, both the first drainage port 41 and the second drainage port 42 are connected to the same sludge discharge channel through pipelines. The common sludge discharge channel avoids the repeated setting of sludge discharge structures and well solves the sludge discharge problem of the double-layer sedimentation tank.

[0037] In summary, for the activated sludge recovery sedimentation tank used in the sewage treatment plant of the present invention, the left side of the tank chamber 1 is communicated with the water outlet of the biological reaction tank, a drainage structure 4 is provided on the right side of the tank chamber 1, and a scum collection channel 2 arranged at intervals up and down with the bottom wall of the tank chamber 1 is provided in the middle of the tank chamber 1. The scum collection channel 2 includes a left side wall 21 and a right side wall 22 arranged at intervals left and right. The upper end surface of the left side wall 21 is below the water surface, and the upper end surface of the right side wall 22 is higher than the water surface. Since the upper end surface of the left side wall 21 is below the water surface, the scum on the top of the tank chamber 1 flows from left to right, crosses the left side wall 21 and flows into the scum collection channel 2. Since the upper end surface of the right side wall 22 is higher than the water surface, it can block the scum flowing into the scum collection channel 2 from flowing to the drainage structure 4. The purified sewage in the tank chamber 1 flows into the right side of the tank chamber 1 through the interval between the scum collection channel 2 and the bottom wall of the tank chamber 1 and enters the drainage structure 4. Therefore, the activated sludge recovery sedimentation tank used in the sewage treatment plant of the present invention can treat and recover the scum floating on the water surface, avoiding the influence of the outflow of activated sludge and other suspended substances on the effluent quality. Moreover, the partition plate 3 divides the right part of the tank chamber 1 into two relatively shallow horizontal flow sedimentation tanks, thereby improving the treatment efficiency of activated sludge and the turbidity removal effect, enabling the effective water depth of the tank chamber 1 to be more effectively utilized and the tank length to be shortened, and further reducing the floor area of the tank body. In the northern regions that require heating, the smaller floor area effectively reduces the engineering quantity of the outer housing and the heating system, thereby reducing the project cost. In addition, in this embodiment, two targeted removal measures of sedimentation and air flotation are respectively adopted for the suspended substances with different densities in the sewage, and the mud-water separation effect is better and the effluent quality is better.

[0038] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. An activated sludge recovery sedimentation tank for a sewage treatment plant, characterized in that, It includes a pool body provided with a pool cavity (1), the left side of the pool cavity (1) is communicated with the water outlet of the biological reaction pool, and a drainage structure (4) is provided on the right side of the pool cavity (1); A horizontally arranged partition board (3) is arranged in the pool cavity (1), the partition board (3) is located between the scum collection channel (2) and the bottom wall of the pool cavity (1), and the partition board (3) is arranged at a left-right interval with the left side wall of the pool cavity (1); the partition board (3) divides the right part of the pool cavity (1) into a scum collection layer (11) and a sediment collection layer (12), and the scum collection layer (11) is located above the sediment collection layer (12); A scum collection channel (2) is provided on the right side of the scum collection layer (11), the scum collection channel (2) is located in the middle of the pool cavity (1) and is arranged at an up-down interval with the bottom wall of the pool cavity (1), the scum collection channel (2) includes a left side wall (21) and a right side wall (22) arranged at a left-right interval, the upper end surface of the left side wall (21) is below the water surface, and the upper end surface of the right side wall (22) is higher than the water surface; a diversion channel (5) for guiding the water in the pool cavity (1) on the left side of the partition board (3) into the scum collection layer (11) is provided on the left side of the scum collection layer (11), and the water outlet of the diversion channel (5) is arranged upward; a water distribution plate (51) is fixed at the water outlet of the diversion channel (5), and a plurality of vertically arranged water permeable holes are arranged at intervals on the water distribution plate (51); the water permeable holes accelerate the water flow speed at the water outlet of the diversion channel (5); The partition board (3) divides the pool cavity (1) into three areas, the first area is a pre-stratification area (13) between the left side wall of the pool cavity (1) and the left side wall of the partition board (3), the second area is the scum collection layer directly above the partition board (3), and the third area is the sediment collection layer directly below the partition board (3); A plate-shaped water distributor (9) is provided on the left side of the pool cavity (1), the plate-shaped water distributor (9) is communicated with the water outlet of the biological reaction pool, and the plate-shaped water distributor (9) is located on the left side of the first area; in the pool depth direction, the partition board (3) is located in the middle of the plate-shaped water distributor (9); a plurality of water outlet holes are arranged at an up-down interval on the plate-shaped water distributor (9), and each water outlet hole is arranged horizontally to the right; After the sewage enters the pre-stratification area (13) from the plate-shaped water distributor (9), it is briefly precipitated in the pre-stratification area (13) into relatively clear sewage at the upper position and relatively turbid sewage at the lower position, the relatively clear sewage enters the scum collection layer (11), and the relatively turbid sewage enters the sediment collection layer (12).

2. The activated sludge recovery sedimentation tank for a sewage treatment plant according to claim 1, wherein An underwater aeration device is provided on the left side of the water inlet of the diversion channel (5).

3. The activated sludge recovery sedimentation tank for sewage treatment plants according to claim 1, characterized in that A filter plate (6) arranged at an up-down interval with the partition board (3) is arranged in the scum collection layer (11), one end of the filter plate (6) is fixedly connected to the bottom of the outer wall of the scum collection channel (2), and the other end of the filter plate (6) extends horizontally to the left and is fixedly connected to the outer wall of the diversion channel (5).

4. The activated sludge recovery sedimentation tank for a sewage treatment plant according to claim 3, characterized in that, The activated sludge recovery sedimentation tank for the sewage treatment plant includes a sludge suction device (7), and the sludge suction port of the sludge suction device (7) is arranged above the filter plate (6).

5. The activated sludge recovery sedimentation tank for a sewage treatment plant according to claim 1, wherein A sludge scraping device (8) is provided at the bottom of the sediment collection layer (12).

6. The activated sludge recovery sedimentation tank for sewage treatment plants according to claim 1, characterized in that, A water collecting ditch (111) extending in the front-rear direction is provided at the upper right part of the scum collection layer (11). The right side wall of the tank body forms the right ditch wall of the water collecting ditch (111), and the top surface of the left side wall of the water collecting ditch (111) is lower than the top surface of the left side wall (21) of the scum collection channel (2). The drainage structure (4) includes a second drainage port (42) and a first drainage port (41) communicated with the water collecting ditch (111). The second drainage port (42) is arranged at the upper right part of the sediment collection layer (12).

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