Method for treating sludge through high-energy waves and application of method

Abstract

The invention discloses a high-energy wave sludge treatment method and application thereof, and belongs to the technical field of sludge treatment. The method comprises the following steps: 1, treating sewage in a biochemical tank, conveying the treated sewage into a secondary sedimentation tank, taking discharged residual sludge, adjusting the concentration of the residual sludge, conveying the residual sludge into a high-energy wave treatment device, and carrying out high-energy wave treatment; 2, introducing the sludge subjected to high-energy wave treatment into dewatering equipment for dewatering to obtain treated sludge and sludge disintegration liquid; and 3, the sludge disintegration liquid flows back to the biochemical pool for resource utilization. According to the method, the sludge treatment cost is directly and effectively saved from the sludge end treatment link, meanwhile, the carbon source adding cost of a sewage treatment system is reduced, the operation conditions are simple and controllable, and the method has the potential of large-scale application.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge treatment, and in particular relates to a method for treating sludge with high-energy waves and an application thereof in reducing the amount of sludge and recycling it as a resource. Background Art

[0002] With the urbanization process and sustained economic development in my country, the discharge of urban sewage has increased significantly, and the number and scale of urban sewage treatment plants have continued to expand, which has led to an increase in the amount of residual sludge generated year by year. In the operating costs of sewage treatment plants, the treatment and disposal costs of residual sludge account for about 20% to 30%. Existing sludge treatment methods mainly include conventional technologies such as mechanical dehydration, but due to the presence of extracellular polymers, surface charge and other characteristics in sludge, the sludge has a strong hydrophilic ability. Water molecules can combine with sludge particles in a variety of ways, resulting in unsatisfactory effects of conventional conditioning and mechanical dehydration. The moisture content of the mud cake after dehydration of the residual sludge and the final mud cake weight directly affect the subsequent treatment and disposal costs of the sludge. Therefore, efficient dehydration of sludge has become one of the main challenges facing sewage treatment plants.

[0003] In order to improve the dewatering effect of sludge, pretreatment technology has gradually attracted attention. Through proper pretreatment, the composition and properties of extracellular polymers and particles in the sludge can be changed, thereby reducing the binding energy of water in the sludge and improving the efficiency and effect of mechanical dewatering. However, existing pretreatment technologies usually have problems such as high processing costs, complex operations and low resource utilization, which are difficult to meet the actual needs of large-scale sludge treatment. Ultrasonic treatment of sludge is a new type of sludge reduction technology. High-intensity ultrasound can be used to break up sludge, tear apart bacterial flocs and bacterial cell walls by generating strong shear forces, release a large amount of organic matter, and improve the dewatering performance of sludge. Patent No. CN115745362A discloses an ultrasonic combined with A 2 The O process achieves sludge reduction and sewage treatment methods, and reduces the net sludge discharge through the "lysis-return sludge" process, but it cannot effectively reduce the volume of sludge terminal treatment, and the sludge disposal volume is still huge. In addition, it requires additional combined processes such as ultrasonic tanks and lysis sludge return, which increases the process area of ​​the sewage treatment plant and increases energy consumption.

[0004] The patent application with publication number CN118495782A discloses a high-energy wave generating device and a method for treating river or lake sediment using high-energy waves. The sediment is treated with high-intensity ultrasonic waves, and the cavitation effect of ultrasonic waves is used to generate instant high temperature, high pressure and strong shear force inside the sediment, thereby breaking the cell wall and cell membrane of the microorganism, dissolving enzymes and cytoplasm from the cells, improving the dehydration performance of the sediment, and decomposing the extracellular polymers of the sediment, promoting sediment reduction and resource utilization. However, it is applied outdoors. The present invention is used to treat river or lake sediment and cannot be directly used indoors in sewage treatment plants. High-energy wave treatment devices are not applicable. In addition, there is no recycling process. If the device is used in sewage treatment plants, there will be a waste of resources. Summary of the invention

[0005] In view of the defects existing in the above-mentioned prior art, in order to solve the problems of high moisture content of residual sludge, unsatisfactory mechanical dehydration effect, high cost of pretreatment technology, complex operation and low resource utilization rate, large volume and large disposal amount of sludge terminal treatment, etc., the purpose of the present invention is to design and provide a method for sludge reduction and resource utilization by high-energy wave treatment. The method of the present invention directly and effectively saves the disposal cost of sludge from the sludge terminal treatment link, while reducing the carbon source addition cost of the sewage treatment system. The operating conditions are simple and controllable, and it has the potential for large-scale application.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a high-energy wave treatment device, comprising a mud inlet pipe, a mud inlet valve, a mud collecting tank, a mud outlet pipe and a mud outlet valve connected in sequence;

[0008] A high-energy wave generator is provided in the middle of the mud collecting tank;

[0009] A condenser and a controller connected to each other are arranged above the high energy wave generator;

[0010] An aeration device is arranged at the bottom of the mud collecting tank.

[0011] The high-energy wave processing device described above, wherein the high-energy wave generator is a probe-type high-energy wave generator.

[0012] In the high-energy wave processing device, the high-energy wave generator, the condenser and the aeration device operate synchronously.

[0013] In the high-energy wave treatment device, the aeration capacity of the aeration device is 10 to 30 L / min.

[0014] In a second aspect, the present invention provides a method for treating sludge using high energy waves, comprising the following steps:

[0015] (1) After the sewage is treated in the biochemical tank, it is transported to the secondary sedimentation tank, and the residual sludge discharged is taken, the concentration of the residual sludge is adjusted, and it is transported to the high-energy wave treatment device as described in claim 1 for high-energy wave treatment;

[0016] (2) passing the sludge treated by high-energy waves in step (1) into a dehydration device for dehydration to obtain treated sludge and sludge cracking liquid;

[0017] (3) The sludge cracking liquid obtained in the above step (2) is returned to the biochemical pool for resource utilization.

[0018] In the method, the high-energy wave treatment time in the high-energy wave treatment device is 5 to 15 minutes.

[0019] The method comprises adjusting the concentration of the excess sludge to 5-15 g / L.

[0020] The method, the ultrasonic frequency output by the high-energy wave generator in the high-energy wave treatment device is 15-20kHz, and the energy density per unit area within a diameter of 50cm is 300-400W / CM 2 .

[0021] In the method, the dehydration equipment is a mechanical dehydration equipment.

[0022] Use of any of the high energy wave treatment devices or any of the methods described in treating excess sludge in a sewage treatment plant.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention uses a unique high-energy wave treatment method to treat the excess sludge in the sewage treatment plant, which can be used as a resource and the carbon source can be recovered, thus reducing the treatment cost and generating new resources. The device of the present invention can cleverly apply the sludge high-energy wave treatment to the sewage treatment process, and make the sewage treatment process form a cycle that is efficient and convenient. The method of the present invention directly and effectively saves the sludge disposal cost from the sludge terminal treatment link, while reducing the carbon source addition cost of the sewage treatment system. The operating conditions are simple and controllable, and it has the potential for large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the high energy wave processing device of the present invention;

[0026] Figure 2 This is a process flow chart of the present invention using high energy wave treatment to achieve sludge reduction and resource utilization;

[0027] Figure 3 This is a flow chart of the device for realizing sludge reduction and resource utilization by high energy wave treatment in the present invention;

[0028] Figure 4 The effect of effective residence time on sludge concentration in Examples 3 to 5 of the present invention;

[0029] Figure 5 The effect of effective residence time on the moisture content of dehydrated sludge in Examples 3 to 5 of the present invention;

[0030] Figure 6 The effect of effective residence time on extracellular polymers of sludge in Examples 3 to 5 of the present invention;

[0031] Figure 7 The effect of effective residence time on COD of cracking liquid in Examples 3 to 5 of the present invention;

[0032] Figure 8 The denitrification of microorganisms using the cracked liquid as a denitrification carbon source in Example 3 of the present invention;

[0033] Fig. 9 The microbial utilization of the cracked liquid as a denitrification carbon source in Example 3 of the present invention;

[0034] Among them: 1-mud inlet pipe, 2-mud inlet valve, 3-mud collecting tank, 4-high energy wave generator, 5-condenser, 6-controller, 7-aeration device, 8-mud outlet pipe, 9-mud outlet valve. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings and embodiments in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] Embodiment 1:

[0037] like Figure 1 As shown, the present invention designs a high-energy wave treatment device for treating excess sludge, comprising a mud inlet pipe 1, a mud inlet valve 2, a mud collecting tank 3, a mud outlet pipe 8 and a mud outlet valve 9 connected in sequence; a high-energy wave generator 4 is provided in the middle of the mud collecting tank 3; a condenser 5 and a controller 6 connected to each other are provided above the high-energy wave generator 4; an aeration device 7 is provided at the bottom of the mud collecting tank 3. The high-energy wave generator 4 is a probe-type high-energy wave generator. The high-energy wave generator 4, the condenser 5 and the aeration device 7 operate synchronously.

[0038] Embodiment 2:

[0039] like Figure 2The figure shows a process flow of using high energy wave treatment to achieve sludge reduction and resource utilization. Since the key of the present invention is to use a high energy wave treatment device to treat the excess sludge in the sewage treatment plant, and the other process flows or parameters are basically the same as the prior art, this embodiment will focus on the description of the high energy wave treatment method in the general sewage biological treatment process.

[0040] First, the residual sludge discharged from the secondary sedimentation tank of the sewage treatment plant is concentrated in a sludge storage chamber, and a high-energy wave treatment device as described in Example 1 is provided. Then, the residual sludge in the sludge storage chamber is transported to the high-energy wave treatment device for high-energy wave treatment; then, the residual sludge after high-energy wave treatment is mechanically dehydrated by a dehydration device to obtain sludge cracking liquid and solid residue; finally, the dehydrated solid residue is transported out for further disposal, and the obtained sludge cracking liquid is returned to the biochemical pool to serve as an external carbon source for the biochemical pool, and then is utilized as a resource by microorganisms.

[0041] Specifically, the process of using high energy wave treatment to achieve sludge reduction and resource utilization is as follows: Figure 3 As shown, in the mud feeding stage, the residual sludge in the mud storage chamber is pumped into the mud collecting tank 3, and the aeration device 7 and the high-energy wave generator 4 in the mud collecting tank 3 are started to treat the sludge. After the liquid level reaches the top of the mud outlet pipe 8, the treated sludge is discharged through the mud outlet pipe 8 and the mud outlet valve 9 and transported to the dehydration equipment for mechanical dehydration. During normal operation, the condenser 5 and the high-energy wave generator 4 are kept in synchronous operation to cool the high-energy wave generator 4; the sludge flow rate of the mud inlet pipe 1 and the mud outlet pipe 8 is kept consistent. The number of series-connected mud collecting tanks in the high-energy wave treatment device depends on the actual sludge treatment requirements.

[0042] Embodiment 3:

[0043] This embodiment adopts the high-energy wave treatment device of the embodiment 1. Furthermore, the three mud collecting tanks 3 adopt a columnar structure with a length and width of 30 cm and a height of 50 cm. The effective volume of each mud collecting tank is about 40 L. The ultrasonic frequency output by the high-energy wave generator 4 is 15 to 20 kHz, and the energy density per unit area within a diameter range of 50 cm reaches 300 to 400 W / CM. 2 .

[0044] The same method of using high-energy wave treatment to achieve sludge reduction and resource utilization as in Example 2 is adopted. Further, the sludge concentration (initial sludge concentration) of the residual sludge in the sludge storage chamber is adjusted to approximately 5, 10, and 15 g / L. The adjusted residual sludge is pumped into the first sludge collecting tank 1 through the second sludge pump 10. The sludge feeding method is the same as the sludge feeding method described in Example 2, and the aeration capacity of the aeration device is set to 20 L / min.

[0045] The sludge was kept in the high energy wave treatment device for different effective residence times (4, 8, 12, 16, 20 min), wherein the flow rates of the sludge inlet pipe 1 and the sludge outlet pipe 8 were always kept consistent. The following experiments were carried out in this process to determine its performance.

[0046] 1. After different high-energy wave treatment times, the initial sludge of different concentrations was filtered and dried, and then weighed to calculate the sludge concentration (g / L).

[0047] The results are as follows Figure 4 As shown in the figure, when the initial sludge concentration is 10g / L, as the effective residence time increases, the sludge concentration continues to decrease and remains at about 8.5g / L, and the sludge concentration is reduced by 15% at most. When the initial sludge concentration is 5g / L, the sludge can effectively reduce the sludge concentration after the sludge effectively stays in the high-energy wave treatment device for 4 to 20 minutes, and the sludge moisture content can be reduced at the same time after vacuum filtration and dehydration. As the effective residence time increases, the sludge concentration continues to decrease and remains at about 4.3g / L, and the sludge concentration is reduced by 14% at most. When the initial sludge concentration is 15g / L, the sludge can effectively reduce the sludge concentration after the sludge effectively stays in the high-energy wave treatment device for 4 to 20 minutes, and the sludge moisture content can be reduced at the same time after vacuum filtration and dehydration. As the effective residence time increases, the sludge concentration continues to decrease and remains at about 13g / L, and the sludge concentration is reduced by 13.3% at the highest.

[0048] 2. Dehydration by vacuum filtration requires the assembly and inspection of the sealing of the vacuum filtration device, and the preparation of a well-mixed sludge sample. When filtering, pour an appropriate amount of sludge into the Buchner funnel, use negative pressure to make the water pass through the filter paper into the filter bottle, and filter again after no obvious liquid seepage on the sludge surface. Finally, take a sample and weigh it, then dry it and weigh it, and calculate the sludge moisture content (%).

[0049] The results are as follows Figure 5As shown in the figure, the moisture content of the sludge after vacuum filtration and dehydration first decreases and then increases with the increase of effective residence time. When the initial sludge concentration is 10g / L, it reaches the lowest value at 12min, and the moisture content of the sludge after dehydration is only 53.3%, which can be reduced by about 29.4% compared with the moisture content of the dehydrated sludge without high-energy wave treatment. When the initial sludge concentration is 5g / L, it reaches the lowest value at 8min, and the moisture content of the sludge after dehydration is 55.8%, which can be reduced by about 23.1% compared with the moisture content of the dehydrated sludge without high-energy wave treatment. When the initial sludge concentration is 15g / L, it reaches the lowest value at 16min, and the moisture content of the sludge after dehydration is 56.7%, which can be reduced by about 24% compared with the moisture content of the dehydrated sludge without high-energy wave treatment. As the high-energy wave treatment time continued to increase, the sludge dewatering performance began to deteriorate significantly. This deterioration may be due to the excessive destruction of the extracellular polymers of the sludge, the release of a large amount of polysaccharides and proteins, the increase of sludge viscosity, and the increase of water content.

[0050] 3. The anthrone-sulfuric acid method and the Coomassie brilliant blue staining method were used to determine the extracellular polymers of the sludge. For the extracellular polymers TB-EPS (mg / L) of the sludge after the above treatment, the anthrone-sulfuric acid method required the extraction of EPS by centrifugation first, and then the sample was added with the freshly prepared anthrone-sulfuric acid reagent, and the reaction was carried out in a boiling water bath to generate a blue-green complex. After cooling, the colorimetric analysis was performed at 620-625nm, and the content was calculated by comparing with the standard curve. The Coomassie brilliant blue staining method required the EPS sample to be obtained by centrifugation, and the dye solution prepared with Coomassie brilliant blue G-250 was added. The reaction was carried out at room temperature for 5-10 minutes to form a blue complex, and the colorimetric analysis was performed at 595nm, and the content was determined by comparing with the standard curve.

[0051] The results are as follows Figure 6 As shown in the figure, the extracellular polymers of sludge decrease with the increase of effective residence time. When the initial sludge concentration is 10g / L, the initial TB-EPS (mg / L) of sludge is 140mg / L, and the high-energy wave treatment for 20min can reduce it to 40mg / L; when the initial sludge concentration is 5g / L, the initial TB-EPS of sludge is 90mg / L, and the high-energy wave treatment for 20min can reduce it to 30mg / L. When the initial sludge concentration is 15g / L, the initial TB-EPS of sludge is 180mg / L, and the high-energy wave treatment for 20min can reduce it to 50mg / L.

[0052] 4. Use the dichromate method to determine the COD of the cracking liquid (i.e. the sludge after high-energy wave treatment and then dehydration to obtain the liquid).

[0053] The results are as follows Figure 7As shown in the figure, after the sludge TB EPS was broken by high-energy waves, it was transferred to the solution. When the initial sludge concentration was 10g / L, the COD of the broken liquid increased from the initial 60-70mg / L to 200-1000mg / L. When the initial sludge concentration was 5g / L, the COD of the broken liquid increased from the initial 50-60mg / L to 200-500mg / L. When the initial sludge concentration was 15g / L, the COD of the broken liquid increased from the initial 80-90mg / L to 300-1400mg / L.

[0054] Embodiment 4:

[0055] In order to verify whether the organic matter in the cracking liquid can be used by organisms, the sludge cracking liquid with different high-energy wave treatment time is used as the carbon source, a certain amount of sodium nitrate is added, and the activated sludge from the sewage plant is taken for anaerobic denitrification and denitrification experiments. The experiment first needs to prepare anaerobic reaction containers, stirring devices, denitrifying bacteria inoculations, simulated wastewater and analytical reagents, and then inoculate denitrifying bacteria in proportion, add simulated wastewater and create an anaerobic environment to start the reaction, and take samples regularly and analyze nitrate nitrogen, nitrite nitrogen and pH value, and finally record data and draw curves to analyze the reaction process. Thus, the nitrate nitrogen concentration (mg / L) and TOC (mg / L) are determined.

[0056] The experimental results are as follows Figure 8 and 9 As shown in the figure, the sludge that has not been treated with high-energy waves has a low content of organic matter in its solution and cannot provide the carbon source required for the activity of denitrifying bacteria in the activated sludge. Therefore, the concentration of nitrate nitrogen in the solution has not changed significantly. However, the sludge cracking liquid after high-energy wave treatment has sufficient organic matter content. After a period of anaerobic denitrification, the nitrate nitrogen in the solution is basically removed. Among them, the sludge cracking liquid treated with high-energy waves for 12 minutes has the best denitrification effect. This proves that after the sludge is treated with high-energy waves, the sludge TB EPS is converted into organic matter in the cracking liquid that is easily biochemically utilized and can serve as a carbon source for microorganisms.

[0057] In summary, as the effective residence time of sludge in the high-energy wave treatment device increases, the moisture content of the bottom sludge can be effectively reduced after dehydration by the dehydration equipment. However, the unlimited extension of its residence time will significantly deteriorate the dehydration performance of the sludge. This deterioration is due to excessive destruction of the extracellular polymers of the sludge, which releases a large amount of polysaccharides and proteins, increases the viscosity of the sludge, and thus increases the moisture content. It not only increases the power consumption and treatment efficiency of the device, but also fails to achieve the ideal reduction effect. Therefore, according to the implementation results, the optimal residence time of sludge in the high-energy wave treatment device is 5 to 15 minutes, and the sludge concentration is preferably 5 to 15 g / L. This device method treats the sludge in a continuous flow, effectively improves the operating efficiency of the device through automated control, and has a significant reduction effect. It directly and effectively saves the disposal cost of sludge from the sludge terminal treatment link, while reducing the carbon source addition cost of the sewage treatment system. The operating conditions are simple and controllable, and it has the potential for large-scale application.

Claims

1. A high energy wave processing device, characterized in that: It comprises a mud inlet pipe (1), a mud inlet valve (2), a mud collecting tank (3), a mud outlet pipe (8) and a mud outlet valve (9) which are connected in sequence; A high-energy wave generator (4) is provided in the middle of the mud collecting tank (3); A condenser (5) and a controller (6) connected to each other are provided above the high-energy wave generator (4); An aeration device (7) is provided at the bottom of the mud collecting tank (3).

2. A high energy wave processing device as claimed in claim 1, characterized in that: The high-energy wave generator (4) is a probe-type high-energy wave generator.

3. A high energy wave processing device as claimed in claim 1, characterized in that: The high-energy wave generator (4), the condenser (5) and the aeration device (7) operate synchronously.

4. A high energy wave processing device as claimed in claim 1, characterized in that: The aeration volume of the aeration device (7) is 10 to 30 L / min.

5. A method for treating sludge with high energy waves, characterized in that: The following steps are involved: (1) After the sewage is treated in the biochemical tank, it is transported to the secondary sedimentation tank, and the residual sludge discharged is taken, the concentration of the residual sludge is adjusted, and it is transported to the high-energy wave treatment device as described in claim 1 for high-energy wave treatment; (2) passing the sludge treated by high-energy waves in step (1) into a dehydration device for dehydration to obtain treated sludge and sludge cracking liquid; (3) The sludge cracking liquid obtained in the above step (2) is returned to the biochemical pool for resource utilization.

6. The method according to claim 5, characterized in that The high energy wave treatment time in the high energy wave treatment device is 5 to 15 minutes.

7. The method according to claim 5, characterized in that The concentration of the excess sludge is adjusted to 5-15 g / L.

8. The method according to claim 5, characterized in that The ultrasonic frequency output by the high-energy wave generator in the high-energy wave treatment device is 15-20kHz, and the energy density per unit area within a diameter of 50cm is 300-400W / CM 2 .

9. The method according to claim 5, characterized in that The dehydration equipment is a mechanical dehydration equipment.

10. Use of the high energy wave treatment device according to any one of claims 1 to 4, or the method according to any one of claims 5 to 9 in treating excess sludge in a sewage treatment plant.

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