Stabilized sludge recycling treatment system and method based on optimized floatation tank

Abstract

Disclosed in the present invention are a stabilized sludge recycling treatment system and method based on an optimized floatation tank, in which sludge recycling is realized by combining an ozone microbubble treatment with land utilization. During the sludge treatment process, a floatation tank having an optimized structure is used, thereby improving the oxidation efficiency of ozone; in addition, a whole-process sludge disposal is used, thereby reducing the transportation cost; and moreover, the dewatered sludge is crushed by using a crusher, thereby increasing the propagation rate of organic matters in the soil on the basis of increasing the specific surface area of the sludge.

Description

A stabilized sludge resource treatment system and method based on optimized flotation tank Technical Field

[0001] The present invention relates to the technical field of sludge treatment, and in particular to a stabilized sludge resource treatment system and method based on an optimized flotation tank. Background Art

[0002] With the continuous advancement of urbanization in my country, the scale of sewage treatment continues to expand, and the output of residual sludge has further increased. At the same time, sludge contains rich organic matter and nutrients such as nitrogen, phosphorus and potassium, making it suitable for land use.

[0003] However, existing stabilization technologies such as anaerobic digestion and aerobic composting have problems such as incomplete disinfection and insufficient deodorization, and are prone to produce foul odors and introduce pathogenic microorganisms when land is used.

[0004] Summary of the Invention

[0005] To address the issues raised in the aforementioned background technology, the present invention discloses a stabilized sludge resource utilization system and method based on an optimized flotation tank. By combining ozone microbubble treatment with land utilization, the system achieves sludge resource utilization while also improving ozone oxidation efficiency during the sludge treatment process.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention is to provide a stabilized sludge resource treatment system based on an optimized flotation tank, comprising: a pre-conditioning tank, an air flotation tank, a biochemical tank, a conditioning tank, a plate and frame filter press, and a crusher;

[0008] The pre-conditioning tank is used to pre-treat the residual sludge entering the pre-conditioning tank and send the pre-treated sludge into the flotation tank;

[0009] The flotation tank utilizes ozone gas microbubbles to circulate and oxidize the excess sludge entering the flotation tank and then sends it to the conditioning tank;

[0010] The conditioning tank uses a dehydrating agent to condition the sludge entering the conditioning tank to form concentrated sludge which is then fed into a plate and frame filter press;

[0011] The biochemical pool is used to receive the clear liquid after being treated in the pre-conditioning pool, the flotation pool and the conditioning pool;

[0012] The plate and frame filter press is used to dewater the sludge entering the plate and frame filter press;

[0013] The crusher is used to crush the sludge fed into the plate and frame filter press, so as to break the sludge into smaller particles.

[0014] In a preferred embodiment, the pretreatment method is preferably to perform preliminary sedimentation and concentration on the excess sludge.

[0015] In a preferred embodiment, an air inlet is provided at the bottom of the preconditioning tank for receiving excess waste gas produced by the flotation tank; a water outlet is also provided at the bottom of the preconditioning tank, and the water outlet is connected to the biochemical tank.

[0016] In a preferred embodiment, the flotation tank is provided with a reaction zone and a sedimentation zone, wherein the reaction zone is connected to the mud outlet of the pre-conditioning tank, a gas collecting hood is provided on the top of the reaction zone, and the gas collecting hood is connected to the air inlet at the bottom end of the pre-conditioning tank through a gas pipeline, a plurality of staggered inclined plate partitions are provided inside the reaction zone to increase the contact distance between the sludge and the ozone microbubbles, and a bubble generator is provided at the bottom of the reaction zone to provide ozone microbubbles;

[0017] The top of the sedimentation zone is provided with a mud discharge port, which is connected to the mud inlet of the conditioning tank; the middle of the sedimentation zone is provided with a water outlet, which is connected to the biochemical tank; the bottom of the sedimentation zone is provided with a reflux port, which is connected to the reaction zone through a reflux pipeline and an inflow pump; the reflux pipeline is also connected to a reclaimed water inlet pipe for replenishing the reflux water volume;

[0018] Among them, the multiple inclined plate partitions include a first inclined plate partition and a second inclined plate partition repeatedly arranged in the transverse direction of the flotation tank reaction zone. A sludge channel is provided between the lower end of the first inclined plate partition and the bottom of the flotation tank, and a sludge channel is provided between the upper end of the second inclined plate partition and the top of the flotation tank. The sludge channels are interconnected, and an S-shaped up and down reciprocating flow channel is formed between the sludge inlet end and the sludge outlet end in the flotation tank reaction zone through all the inclined plate partitions. The bubble generator is provided in the reaction zone between two adjacent inclined plate partitions.

[0019] In a preferred embodiment, a water outlet is provided at the bottom of the conditioning pool, and the water outlet is connected to the biochemical pool.

[0020] A second aspect of the present invention is to provide a method for resource-based treatment of stabilized sludge based on an optimized flotation tank. Based on the first aspect, a stabilized sludge resource-based treatment system based on an optimized flotation tank is provided. The method comprises the following steps:

[0021] S1: The remaining sludge is sent to the pre-conditioning tank for preliminary sedimentation, and the treated supernatant is passed into the biochemical tank;

[0022] S2: The excess sludge entering the flotation tank is oxidized by circulating ozone gas microbubbles and then sent to the conditioning tank. The clear liquid after the reaction is passed into the biochemical tank.

[0023] S3: Conditioning the sludge treated in the flotation tank using a dehydrating agent, feeding the concentrated sludge after conditioning into a plate and frame filter press, and passing the supernatant produced after conditioning into a biochemical tank;

[0024] S4: Dewatering the sludge entering the plate and frame filter press, and sending the dehydrated sludge into a crusher for crushing;

[0025] S5: The crushed sludge is sent to the sewage treatment plant for landscaping.

[0026] In a preferred embodiment, the step S1 further comprises aerating the sludge by utilizing the waste gas refluxed from the flotation tank to avoid anaerobic fermentation of the sludge.

[0027] In a preferred embodiment, the ozone gas is preferably generated by feeding oxygen into an ozone generator for oxidation.

[0028] In a preferred embodiment, in step S2, the residence time of the sludge in the flotation tank is preferably 1 to 5 hours, more preferably 1 to 4 hours.

[0029] In a preferred embodiment, the oxidation reaction time is preferably 1 to 4 hours, more preferably 2 to 3 hours.

[0030] In a preferred embodiment, the step S2 further includes setting a reclaimed water inlet pipe at the bottom of the flotation tank to replenish the reduced water volume of the supernatant liquid flowing back to the plant area to meet the reflux water volume.

[0031] In a preferred embodiment, in step S2, the sludge treated by the oxidation reaction includes an upper layer of sludge and a lower layer of sludge. The upper layer of sludge is passed into a conditioning tank, and the lower layer of sludge is returned to the reaction zone through a reflux pipeline to react again.

[0032] In a preferred embodiment, the dehydrating agent is preferably one or more of building powder, polyferric sulfate, and a mixture of building powder and polyferric sulfate.

[0033] In a preferred embodiment, the addition amount of the building powder is preferably 10%-15% of the absolute dry mass of the sludge.

[0034] In a preferred embodiment, the mass fraction of the polyferric sulfate is preferably 10%-15%.

[0035] In a preferred embodiment, the dosage of the polyferric sulfate is preferably 3%-5% of the absolute dry mass of the sludge.

[0036] In a preferred embodiment, the plate and frame pores in the plate and frame filter press are preferably 120-150 meshes.

[0037] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0038] (1) The present invention discloses a stabilized sludge resource treatment system based on an optimized flotation tank, which adopts a full-process sludge disposal method to reduce transportation costs.

[0039] (2) The present invention discloses a stabilized sludge resource treatment system based on an optimized flotation tank, which uses an optimized flotation tank to improve the ozone oxidation efficiency.

[0040] (3) The present invention discloses a stabilized sludge resource processing system based on an optimized flotation tank, which returns the clear liquid in the flotation tank, the supernatant in the conditioning tank, and the supernatant in the plate and frame filter press to the biochemical tank, thereby improving the resource utilization rate of pollutants in the sludge.

[0041] (4) The present invention discloses a stabilized sludge resource processing system based on an optimized flotation tank, which uses a crusher to crush the dewatered sludge into particles with a diameter of about 0.5 cm, thereby increasing the specific surface area of ​​the sludge and the transfer rate of organic matter in the soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings that constitute part of this application are used to provide further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute improper limitations on this application.

[0043] FIG1 is a schematic flow chart of a method for resource utilization of stabilized sludge based on an optimized flotation tank according to the present invention.

[0044] FIG2 is a flow chart of a stabilized sludge resource treatment system based on an optimized flotation tank according to the present invention.

[0045] FIG3 is a schematic structural diagram of an air flotation tank in a stabilized sludge resource treatment system based on an optimized air flotation tank according to the present invention.

[0046] FIG4 is a CST diagram showing the variation of sludge capillary water absorption time with the dosage of dehydrating agent in a stabilized sludge resource treatment method based on an optimized flotation tank according to the present invention.

[0047] FIG5 is a graph showing changes in sludge EC value with oxidation reaction time in a stabilized sludge resource treatment method based on an optimized flotation tank according to the present invention. DETAILED DESCRIPTION

[0048] The following describes the embodiments of the present invention using specific examples and accompanying drawings. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through other different specific examples, and the details in this specification may be modified and altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0049] 2 and 3 , the present invention provides a stabilized sludge resource treatment system based on an optimized flotation tank, comprising: a pre-conditioning tank 1, an air flotation tank 2, a biochemical tank 3, a conditioning tank 4, a plate and frame filter press 5, and a crusher 6;

[0050] The pre-conditioning tank 1 is used to pre-treat the residual sludge entering the pre-conditioning tank 1 and send the pre-treated sludge into the flotation tank 2;

[0051] The flotation tank 2 utilizes ozone gas microbubbles to circulate and oxidize the excess sludge entering the flotation tank 2 and then sends it to the conditioning tank 4;

[0052] The biochemical pool 3 is used to receive the clear liquid treated by the pre-conditioning pool 1, the flotation pool 2 and the conditioning pool 4;

[0053] The conditioning tank 4 uses a dehydrating agent to condition the sludge entering the conditioning tank 4 to form concentrated sludge, which is then sent to the plate and frame filter press 5;

[0054] The plate and frame filter press 5 is used to dewater the sludge entering the plate and frame filter press 5;

[0055] The crusher 6 is used to crush the sludge fed into the plate and frame filter press 5 into smaller particles.

[0056] Specifically, the pretreatment method includes preliminary sedimentation and concentration of the residual sludge; at the same time, an air inlet is provided at the bottom of the preconditioning tank 1 for receiving excess waste gas produced by the flotation tank; a water outlet is also provided at the bottom of the preconditioning tank 1, and the water outlet is connected to the biochemical tank 3.

[0057] In addition, the flotation tank 2 is provided with a reaction zone and a sedimentation zone, wherein the reaction zone is connected to the mud outlet of the pre-conditioning tank 1, a gas collecting hood is provided on the top of the reaction zone, and is connected to the air inlet at the bottom end of the pre-conditioning tank 1 through a gas pipeline, and an inclined plate partition is provided inside the reaction zone to increase the contact distance between the sludge and the ozone microbubbles, and a bubble generator is provided at the bottom of the reaction zone to provide ozone microbubbles;

[0058] The top of the sedimentation zone is provided with a mud discharge port, which is connected to the mud inlet of the conditioning tank 4; the middle of the sedimentation zone is provided with a water outlet, which is connected to the biochemical tank 3; the bottom of the sedimentation zone is provided with a reflux port, which is connected to the reaction zone through a reflux pipeline and an inflow pump; the reflux pipeline is also connected to a reclaimed water inlet pipe;

[0059] In addition, the multiple inclined plate partitions include a first inclined plate partition and a second inclined plate partition repeatedly arranged along the transverse direction of the flotation tank reaction zone. A sludge channel is provided between the lower end of the first inclined plate partition and the bottom of the flotation tank, and a sludge channel is provided between the upper end of the second inclined plate partition and the top of the flotation tank. The sludge channels are interconnected, and an S-shaped up and down reciprocating flow channel is formed between the sludge inlet end and the sludge outlet end in the flotation tank reaction zone through all the inclined plate partitions. The bubble generator is provided in the reaction zone between two adjacent inclined plate partitions.

[0060] At the same time, a water outlet is provided at the bottom of the conditioning pool 4 and is connected to the biochemical pool 3 .

[0061] The following is further described by specific examples:

[0062] Example

[0063] Refer to the flowchart shown in Figure 1,

[0064] S1: The residual sludge is sent to the pre-conditioning tank 1 through the sludge inlet pipe for preliminary sedimentation, and the treated supernatant is passed into the biochemical tank 3;

[0065] S2: The excess sludge sent to the flotation tank 1 is circulated with ozone gas microbubbles for oxidation reaction for 2 hours. After the reaction is completed, it is sent to the conditioning tank 4, and the clear liquid after the reaction is passed into the biochemical tank 3. At the same time, the waste gas generated during the reaction is returned to the pre-conditioning tank 1 through the waste gas return pipe to aerate the sludge to avoid anaerobic fermentation of the sludge;

[0066] S3: The sludge treated in the flotation tank 2 is conditioned using a mixture of polyferric sulfate and building powder, and the conditioned concentrated sludge is fed into the plate-and-frame filter press 5. The supernatant produced after conditioning is passed into the biochemical tank 3.

[0067] The amount of building powder added is 15% of the absolute dry mass of the sludge, and the amount of polyferric sulfate solution (mass fraction 11%) added is 5% of the absolute dry mass of the sludge;

[0068] S4: Dewatering the sludge entering the plate and frame filter press 5 and sending the dehydrated sludge to the crusher 6 for crushing;

[0069] S5: The crushed sludge is sent to the sewage treatment plant for landscaping.

[0070] As can be seen from Figure 4, as the dosage of PFS increases, the more powder is added, the smaller the CST value is, indicating that the combined addition of building powder and polyferric sulfate can reduce the dosage of polyferric sulfate and achieve similar dehydration effects.

[0071] As can be seen from Figure 5, without ozone oxidation, the EC value of the sludge is higher than 250Ms / m3 when 15% polyferric sulfate is directly added; after 1 hour of oxidation, the EC value obtained after adding 15% polyferric sulfate is slightly lower than that after adding 30% polyferric sulfate; after 2 hours of oxidation, the EC value of the sludge is reduced to below 50Ms / m3 when 5% polyferric sulfate is added; when 3 hours of oxidation, when the amount of polyferric sulfate is 0%, 10% and 15% respectively, the EC value of the sludge gradually increases; after 4 hours of oxidation, the EC value of the sludge is about 100Ms / m3; the above experimental data show that aeration, dehydration, filtration and crushing of sludge based on optimized flotation tank can effectively reduce the EC value of sludge, stabilize the sludge and reduce the hazards of sludge land use.

[0072] In summary, the present invention discloses a stabilized sludge resource treatment system and method based on an optimized flotation tank, which combines ozone microbubble technology with sludge resource utilization. While improving sludge resource utilization, it also achieves sludge fragmentation and increases the transfer rate of organic matter in the soil.

[0073] While the specific embodiments of the present invention have been described in detail above, these are merely exemplary and the present invention is not limited thereto. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, any equivalent changes and modifications made without departing from the spirit and scope of the present invention are intended to be encompassed within the scope of the present invention.

Claims

1. A stabilized sludge resource treatment system based on an optimized flotation tank, characterized in that: include: Pre-conditioning tank (1), air flotation tank (2), biochemical tank (3), conditioning tank (4), plate and frame filter press (5) and crusher (6); The pre-conditioning tank (1) is used to pre-treat the residual sludge entering the pre-conditioning tank (1), and to send the pre-treated sludge into the flotation tank (2); The flotation tank (2) utilizes ozone gas microbubbles to circulate and oxidize the residual sludge entering the flotation tank (2) and then sends it to the conditioning tank (4); The conditioning tank (4) uses a dehydrating agent to condition the sludge entering the conditioning tank (4) to form concentrated sludge, which is then sent to a plate and frame filter press (5); The biochemical pool (3) is used to receive the clear liquid treated by the pre-conditioning pool (1), the flotation pool (2) and the conditioning pool (4); The plate and frame filter press (5) is used to dewater the sludge entering the plate and frame filter press (5); The crusher (6) is used to crush the sludge fed into the plate and frame filter press (5) so as to break the sludge into smaller particles.

2. According to claim 1, a stabilized sludge resource treatment system based on an optimized flotation tank is characterized in that: The bottom of the pre-conditioning tank (1) is provided with an air inlet for receiving the excess waste gas produced by the flotation tank; the bottom of the pre-conditioning tank (1) is provided with a water outlet, which is connected to the biochemical tank (3).

3. A system for synchronously removing new pollutants according to claim 1, characterized in that: The flotation tank (2) is provided with a reaction zone and a sedimentation zone, wherein the reaction zone is connected to the mud outlet of the pre-conditioning tank (1), a gas collecting hood is provided at the top of the reaction zone, and is connected to the bottom air inlet of the pre-conditioning tank (1) through a gas pipeline, an inclined plate partition is provided inside the reaction zone to increase the contact distance between the sludge and the ozone microbubbles, and a bubble generator is provided at the bottom of the reaction zone to provide ozone microbubbles; The top of the sedimentation zone is provided with a mud discharge port, which is connected to the mud inlet of the conditioning pool (4); the middle of the sedimentation zone is provided with a water outlet, which is connected to the biochemical pool (3); the bottom of the sedimentation zone is provided with a reflux port, which is connected to the reaction zone through a reflux pipeline and an inflow pump; the reflux pipeline is also connected to a reclaimed water inlet pipe for replenishing the reflux water volume; The plurality of inclined plate partitions include a first inclined plate partition and a second inclined plate partition repeatedly arranged in the transverse direction of the reaction zone of the flotation tank, a sludge channel is formed between the lower end of the first inclined plate partition and the bottom of the flotation tank, and a second inclined plate partition is formed between the lower end of the first inclined plate partition and the bottom of the flotation tank. A sludge channel is formed between the upper end of the plate partition and the top of the flotation tank. The sludge channels are interconnected to form an S-shaped up and down reciprocating flow channel between the sludge inlet and outlet ends in the reaction zone of the flotation tank through all inclined plate partitions. The bubble generator is arranged in the reaction zone between two adjacent inclined plate partitions.

4. According to claim 1, a stabilized sludge resource treatment system based on an optimized flotation tank is characterized in that: The bottom of the conditioning pool (4) is provided with a water outlet, which is connected to the biochemical pool (3).

5. A method for resource utilization of stabilized sludge based on optimized flotation tank, characterized in that: Based on a stabilized sludge resource treatment system based on an optimized flotation tank as described in any one of claims 1 to 4, the method comprises the following steps: S1: The residual sludge is sent to the pre-conditioning tank (1) for preliminary sedimentation, and the treated supernatant is passed to the biochemical tank (3); S2: The excess sludge entering the flotation tank (1) is circulated with ozone gas microbubbles for oxidation reaction and then sent to the conditioning tank (4), and the clear liquid after the reaction is passed into the biochemical tank (3); S3: using a dehydrating agent to condition the sludge after being treated in the flotation tank (2), and sending the conditioned concentrated sludge into a plate and frame filter press (5), and the supernatant produced after conditioning is passed into a biochemical tank (3); S4: dehydrating the sludge entering the plate and frame filter press (5), and sending the dehydrated sludge to a crusher (6) for crushing; S5: The crushed sludge is sent to the sewage treatment plant for landscaping.

6. The method for resource utilization of stabilized sludge based on optimized flotation tank according to claim 5, characterized in that: The step S1 also includes aerating the sludge using the waste gas refluxed from the flotation tank (2) to avoid anaerobic fermentation of the sludge.

7. The method for resource utilization of stabilized sludge based on optimized flotation tank according to claim 5, characterized in that: In the step S2, the sludge stays in the flotation tank for 1 to 5 hours.

8. The method for resource utilization of stabilized sludge based on optimized flotation tank according to claim 5, characterized in that: In step S2, the sludge treated by the oxidation reaction includes an upper layer of sludge and a lower layer of sludge. The upper layer of sludge is passed into a conditioning tank, and the lower layer of sludge is returned to the reaction zone through a reflux pipeline to react again.

9. The method for resource utilization of stabilized sludge based on optimized flotation tank according to claim 5, characterized in that: The oxidation reaction time is 1 to 4 hours.

10. The method for resource utilization of stabilized sludge based on optimized flotation tank according to claim 5, characterized in that: The dehydrating agent is preferably one or more of building powder, polyferric sulfate, and a mixture of building powder and polyferric sulfate; wherein the addition amount of the building powder is preferably 10%-15% of the absolute dry mass of the sludge, the mass fraction of the polyferric sulfate is preferably 10%-15%, and the addition amount of the polyferric sulfate is preferably 3%-5% of the absolute dry mass of the sludge.

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