A sludge reduction and resource utilization method based on three-stage separation of sludge and cell disruption

Abstract

The present application belongs to the field of sludge treatment in sewage plant, and particularly relates to a sludge reduction and resource utilization method based on combined use of sludge three-stage separation and cell disruption. The sludge treatment process is as follows: (1) first-stage sludge separation (sludge concentration and dewatering, external transportation) -> sludge wall breaking -> second-stage separation -> third-stage separation -> concentration and dewatering -> external transportation; (2) first-stage sludge separation (sludge backflow) -> sludge wall breaking -> second-stage separation -> third-stage separation -> concentration and dewatering -> external transportation. The first-stage separation tank mainly separates sludge and mud through water force, with high water force load; the second-stage separation tank is a combination of physical treatment and chemical treatment, separates high-density sludge and low-density mud through water force, with low water force load, and is supplemented by chemical sludge disruption; the third-stage separation tank is a sludge-water separation tank based on density difference separation, and adopts a sedimentation tank mode. Each stage of separation tank discharges mud (water) at the upper layer and sludge at the lower layer. The carbon source recovery rate of the method is above 90%, and the sludge reduction rate is about 65-70%.

Description

Technical Field

[0001] This invention belongs to the field of sludge treatment technology, and specifically relates to a sludge reduction and resource utilization method based on the combined use of three-stage sludge separation and cell breakdown. Background Technology

[0002] Excess sludge is formed during the biological wastewater treatment process, when microorganisms continuously proliferate and produce a large amount of sludge mainly composed of organic matter, making it difficult to dispose of during the wastewater treatment process.

[0003] Traditional wastewater sludge treatment typically involves a thickening-dewatering-drying process, ultimately resulting in landfilling, incineration, or use as building materials. This process consumes enormous amounts of chemicals and energy, leading to high costs. A wastewater treatment plant with a daily capacity of 100,000 tons often produces tens of tons of wet wastewater sludge (typically with a moisture content of around 80%). Sludge treatment not only incurs energy and material costs, but the final sludge usually needs to be transported for disposal, often costing hundreds of yuan per ton of dry sludge. These high costs place a significant economic burden on enterprises. Furthermore, existing wastewater treatment processes require substantial carbon sources to maintain nitrogen and phosphorus removal efficiency. However, many wastewater treatment plants (especially in southern regions) lack sufficient carbon sources and must purchase them to compensate for this deficiency. Therefore, converting the organic matter in sludge into a carbon source could significantly reduce the amount of wastewater sludge, achieving sludge reduction, while simultaneously addressing the carbon source shortage problem in wastewater treatment. Thus, sludge decomposition methods that achieve carbon source recovery and reduction are of paramount importance. To address this issue, many researchers have focused on the combined thermal and alkaline treatment of sludge. While this method does achieve good carbon source recovery from sludge, it is costly, involves complex equipment operation, and is not economically viable. Therefore, this paper proposes a sludge reduction and resource recovery method based on a three-stage sludge separation combined with cell disruption. Summary of the Invention

[0004] To address the aforementioned issues, this invention proposes a sludge reduction method based on a three-stage sludge-sludge separation process that simultaneously breaks down sludge cells, taking into account the composition of residual sludge as either organic or inorganic, with a significant portion of the inorganic matter consisting of fine sand particles. The key to this technology is employing a suitable method to separate the inorganic matter from the sludge, which becomes the primary component of the final residual sludge discharge. The activated sludge proliferated in the system is no longer considered for discharge. Instead, the organic matter in the sludge is treated using alkaline degradation, which breaks down organic particles and cells into soluble COD. Particulate organic matter that cannot be completely broken down by alkali can be recycled back to the main wastewater treatment process. Through repeated recycling, the organic matter in the final sludge is essentially broken down and further utilized for denitrification. The final sludge discharged from the system (excluding chemical sludge) comes from the residue after sludge-sludge separation and has a high inorganic content.

[0005] The above objectives can be achieved through the following methods:

[0006] This invention provides a sludge reduction and resource utilization method based on a three-stage sludge separation and cell disruption combined with sludge treatment. The sludge treatment process is as follows: primary sludge separation → (concentration) → secondary sludge separation → tertiary separation → concentration → dewatering → off-site transportation. The process includes the following steps:

[0007] (1) The primary separation tank is used to separate the remaining sludge from the organic sludge. The inorganic particulate primary sludge is separated from the organic sludge. If the carbon source loss caused by the discharge of the primary sludge does not affect the carbon source requirement of the main process (i.e., the volatile matter ratio of the primary sludge is relatively small, and further calculations are needed based on the specific process parameters of the wastewater treatment plant), then 90-95% of the organic sludge is returned to the main process. It can be returned to any structure of the wastewater treatment plant. 5-10% of the organic sludge is concentrated and then enters the next step of treatment. The primary sludge is concentrated and dewatered before being transported off-site. If the carbon source loss caused by the discharge of the primary sludge affects the carbon source requirement of the main process (i.e., the volatile matter ratio of the primary sludge is relatively large, as above), then all the organic sludge is returned to the main process, and the primary sludge enters the next step of treatment. The main process is a biological nitrogen and phosphorus removal process for wastewater treatment. For example, A 2 The / O process mainly includes anaerobic treatment, anoxic treatment, and aerobic treatment.

[0008] (2) The small amount of organic sludge or primary residue is subjected to cell wall breaking treatment using cell wall breaking machinery, and the broken material is then processed in the next step.

[0009] (3) The material after cell wall breaking is separated into sludge in a secondary separation tank. The sludge obtained from the secondary separation is returned to the anoxic tank of the main process, and the secondary sludge is processed in the next step. The main function of the secondary separation tank is to separate fine particulate inorganic matter. The secondary function of the secondary separation tank is to break down the sludge. Strong alkaline agents such as sodium hydroxide and calcium oxide are added to break down the sludge cells.

[0010] (4) The secondary sludge is separated into tertiary sludge using a tertiary separation tank. The obtained tertiary sludge is concentrated and dewatered before being transported off-site, and the obtained wastewater is returned to the anoxic tank of the main process.

[0011] As a further improvement to the above technical solution, the primary separation tank adopts a high hydraulic load, with a hydraulic load >20m. 3 / (m 2 •h); The secondary separation tank adopts a low hydraulic load, with a hydraulic load <0.3m. 3 / (m 2 •h), and the hydraulic retention time (HRT) > 24h; the three-stage separation uses a medium hydraulic load of 0.6–1.0m. 3 / (m 2 ·h).

[0012] As a further improvement to the above technical solution, the primary separation tank is divided into a turbulent zone, a transition zone, and a static zone. The Reynolds number in the turbulent zone is >3000, the Reynolds number in the transition zone is 10-2000, and the Reynolds number gradually decreases from top to bottom. The bottom of the static zone is filled with sludge and is in a static state, and the Reynolds number of the water in the gaps between the sludge is zero.

[0013] As a further improvement to the above technical solution, the volume ratio of the turbulent zone, the transition zone and the static zone is 2:3:5, the total height of the primary separation tank is 6-8m, and when the circulation inside the tank is achieved by using a hydraulic vortex method, the diameter-to-depth ratio is not greater than 0.3.

[0014] As a further improvement to the above technical solution, the primary separation tank is mechanically stirred, and the secondary separation tank is mechanically stirred or air stirred.

[0015] As a further improvement to the above technical solution, the main functions of the primary separation tank and the secondary separation tank are both sludge separation, and the main function of the tertiary separation tank is sludge-water separation (especially light sludge fragments are carried away by the water flow). The tertiary separation tank is constructed as a sedimentation tank, and the secondary sludge enters the tertiary separation tank after being diluted by sewage.

[0016] As a further improvement to the above technical solution, the agents added to the cell wall breaking tank are sodium hydroxide and calcium oxide, and the dosage of the agents is 6-12% of the dry solids of the sludge entering the tank.

[0017] As a further improvement to the above technical solution, if the carbon source loss caused by primary slag discharge does not affect the process's demand for carbon sources (the volatile matter content of primary slag is relatively low), then the process flow follows... Figure 1 In this manner, a small amount of organic sludge is concentrated before entering the next stage of treatment. The concentrated organic sludge has a moisture content of 93-95%. If the carbon source loss caused by the primary slag discharge affects the process's carbon source requirements (the primary slag has a relatively high volatile matter content), the process flow follows... Figure 2 In this way, the slag discharged from the primary separation is further processed, and all the sludge discharged from the primary separation is recycled.

[0018] As a further improvement to the above technical solution, when the organic matter content of the tertiary slag is >20%, cationic PAM is added to the inlet pipe of the tertiary separation tank at a dosage of 0.01-0.03%.

[0019] As a further improvement to the above technical solution, the inorganic matter in the residual sludge has a density greater than that of water, and the specific gravity of the inorganic fine sand is 2.5 g / cm³. 3 The density of organic matter in the remaining sludge is close to that of water, with a specific gravity of 1.002–1.003 g / cm³. 3 .

[0020] The technical principle of this invention is:

[0021] The density of inorganic matter in sludge is significantly greater than that of water; generally, the specific gravity of inorganic fine sand reaches 2.5 g / cm³. 3 The density of organic matter in sludge is very close to that of water, with a specific gravity of only 1.002–1.003 g / cm³ under normal circumstances. 3 Based on this characteristic, when the Reynolds number in the separation tank is large, the sedimentation of light sludge is disturbed, and the stratified sedimentation of the sludge is disrupted, allowing fine sand to be separated from organic matter. Therefore, the primary separation tank needs to meet the following functional and structural characteristics:

[0022] (1) The primary separation tank needs to have significant stratification and height, divided into turbulent zone, transition zone and static zone. The Reynolds number of the turbulent zone is large enough to break the sludge stratification sedimentation, generally greater than 3000, and typically above 20000. The hydraulic conditions of the transition zone can be provided by the rotational friction of the turbulent zone, that is, no stirring measures are set in the transition zone, and the Reynolds number should be controlled between 2000 and 10, and the Reynolds number gradually decreases from the top to the bottom. There is a certain amount of sludge accumulation in the static zone, so the sludge accumulated at the bottom of the static zone is in an almost completely static state, and the Reynolds number of the water in the sludge gap is almost zero.

[0023] (2) The volume ratio of the turbulent zone, the transition zone and the static zone can generally be controlled at 2:3:5. Generally speaking, the total height needs to be greater than 6 to 8 m. When the hydraulic vortex method is used to achieve the circulation in the pool, the diameter-to-depth ratio should not be too large and should not be greater than 0.3.

[0024] (3) In order to reduce the amount of organic matter crossing the transition zone into the bottom static zone, a certain amount of sewage can be introduced into the transition zone. On the one hand, this promotes the upward flow of water in the transition zone, and on the other hand, it dilutes the organic sludge that slides down from the upper turbulent zone, thus avoiding the organic matter crossing the transition zone due to the formation of stratified sedimentation.

[0025] (4) A method to maintain a high Reynolds number in the turbulent zone is to introduce water along the tangential direction of the side of the pool wall.

[0026] The secondary separation tank uses a very low hydraulic load, typically <0.3m. 3 / (m 2 The secondary separation tank has a certain flow velocity in the circumferential direction, and under these hydraulic conditions, extremely fine sludge easily settles. At the same time, the hydraulic retention time in the secondary separation tank is long, generally HRT>24h, thus achieving the separation of sludge fragments from fine sludge.

[0027] The essential function of a tertiary separation tank is as a sedimentation tank. Its main purpose is to separate fine sludge from water, while simultaneously washing away small amounts of sludge fragments from the fine sludge. Therefore, the hydraulic loading value should not be too high (otherwise the fine sludge will have difficulty settling) nor too low (otherwise sludge fragments will also settle), and is generally selected from 0.6 to 1.0 m. 3 / (m 2 ·h) is sufficient.

[0028] The beneficial effects of this invention are as follows: A sludge reduction method based on three-stage sludge-sludge separation and simultaneous sludge cell breakdown separates inorganic matter from the sludge, which is then used as the main component of the final residual sludge discharge. The activated sludge proliferated in the system is no longer considered for discharge. Instead, the organic matter in the sludge is treated using alkaline breakdown, which breaks down organic particles and cells into soluble COD. Particulate organic matter that cannot be completely broken down by alkali can be recycled back to the main wastewater treatment process. Through repeated recycling, the organic matter in the final sludge is essentially broken down and further utilized by denitrification. The final sludge discharged from the system (excluding chemical sludge) comes from the residue after sludge-sludge separation and has a high inorganic content. This method achieves a carbon source recovery rate of over 90% and a sludge reduction rate of approximately 65-70%. The technology is simple, safe, reliable, and has low operating costs. It achieves a high degree of sludge reduction and high economic benefits from carbon source recovery, efficiently realizing sludge reduction, resource recovery, and harmlessness. Based on the results of small-scale tests, by controlling appropriate operating parameters, the organic matter content in the sludge can be as low as 10-15%. For a wastewater treatment plant with a traditional dry sludge discharge of 10 t / d, the organic matter content of the dry sludge is 50%, and the organic matter discharge is 5 t / d. Using the technology of this invention, the final sludge discharge is only 3.0-3.5 t / d, of which the organic matter discharge is <0.5 t / d. Therefore, the actual carbon source recovery rate is >90%, and the sludge reduction rate is approximately 65-70%, demonstrating significant technological advantages. Depending on the properties of the primary separation sludge, if the organic matter content is low and the carbon source recovery rate is high, the sludge can be directly dewatered. If the organic matter content of the primary sludge is high, further treatment is required to ensure that the carbon source recovery rate meets the process requirements. Since the recovered carbon source already meets the needs, the wastewater treatment plant no longer needs to purchase carbon sources, significantly reducing sludge disposal costs and resulting in substantial economic benefits. This invention is only applicable to wastewater treatment plants with biological nitrogen removal capabilities. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process flow (process for primary slag overrun treatment) of Embodiment 1 of the present invention.

[0030] Figure 2 This is a schematic diagram of the process flow (process of primary slag full-process treatment) of Embodiment 2 of the present invention. Detailed Implementation

[0031] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0032] This invention discloses a sludge reduction and resource recovery method based on a three-stage sludge separation and cell disruption combined with the following steps:

[0033] (1) The remaining sludge to be treated is separated in a primary separation tank. The inorganic particulate sludge in the remaining sludge is separated from the organic sludge. If the carbon source loss caused by the discharge of the primary sludge does not affect the carbon source requirement of the main process, most of the organic sludge is returned to the main process, and a small amount of organic sludge is concentrated and then enters the next step of treatment. The primary sludge is concentrated and dewatered and then transported off-site. If the carbon source loss caused by the discharge of the primary sludge affects the carbon source requirement of the main process, all of the organic sludge is returned to the main process, and the primary sludge enters the next step of treatment. The main process is a biological denitrification process for wastewater treatment. For example, A 2 The / O process mainly includes anaerobic treatment, anoxic treatment, and aerobic treatment.

[0034] (2) The small amount of organic sludge or primary residue is subjected to cell wall breaking treatment using cell wall breaking machinery, and the broken material is then processed in the next step.

[0035] (3) The material after cell wall breaking is separated into sludge in a secondary separation tank. The sludge obtained from the secondary sludge separation is returned to the anoxic tank of the main process, and the secondary sludge is processed in the next step.

[0036] (4) The secondary sludge is separated into tertiary sludge using a tertiary separation tank. The obtained tertiary sludge is concentrated and dewatered before being transported off-site, and the obtained wastewater is returned to the anoxic tank of the main process.

[0037] Depending on the properties of the primary separation slag, if the organic matter content is low and the carbon source recovery rate is high, the slag can be directly dewatered. If the organic matter content of the primary slag is high, further treatment is required to ensure that the carbon source recovery rate meets the process requirements. Since the recovered carbon source already meets the needs, the wastewater treatment plant no longer needs to purchase carbon sources, significantly reducing sludge disposal costs, thus resulting in significant economic benefits. This invention is only applicable to wastewater treatment plants with biological nitrogen removal capabilities.

[0038] By controlling appropriate operating parameters in sludge reduction and resource recovery methods, the organic matter content in the sludge discharge can be as low as 10-15%. Taking a wastewater treatment plant with an oven-dried sludge discharge rate of 10 t / d as an example, with an oven-dried sludge organic matter content of 50%, the organic matter discharge rate would be 5 t / d. However, using the technology of this invention, the final sludge discharge rate would only be 3.0-3.5 t / d, of which the organic matter discharge rate would be <0.5 t / d. Therefore, the actual carbon source recovery rate would be >90%, and the sludge reduction rate would be approximately 65-70%, demonstrating significant technological advantages.

[0039] Example 1

[0040] like Figure 1As shown, a sludge reduction and resource utilization method based on the combined use of three-stage sludge separation and cell disruption is presented. The sludge treatment process is as follows: primary sludge separation (sludge thickening and dewatering) → sludge thickening → secondary sludge separation → tertiary separation → thickening → dewatering → off-site transportation. The process includes the following steps:

[0041] (1) The primary separation tank is used to separate the residual sludge from the organic sludge. The inorganic particulate residue in the residual sludge is separated from the organic sludge. The carbon source loss caused by the discharge of the primary residue does not affect the carbon source requirements of the main process (the volatile matter ratio of the primary residue is relatively small, and further calculations are needed based on the specific process parameters of the wastewater treatment plant, such as <20%). 90-95% (by mass) of the organic sludge is returned to the main process, and can be returned to any structure in the wastewater treatment plant. 5-10% (by mass) of the organic sludge is concentrated and then enters the next step of treatment. The concentrated organic sludge has a water content of 93-95%. The primary residue is concentrated and dewatered before being transported off-site. The primary separation tank adopts a high hydraulic load, with a hydraulic load >20m. 3 / (m 2 ·h); The primary separation tank is divided into three layers, from top to bottom: turbulent zone, transition zone and quiescent zone. The Reynolds number in the turbulent zone is >3000, the Reynolds number in the transition zone is 10 to 2000, and the Reynolds number gradually decreases from top to bottom. The bottom of the quiescent zone is filled with sludge and is in a quiescent state. The Reynolds number of the water in the gaps between the sludge is zero.

[0042] The density of inorganic matter in sludge is significantly greater than that of water; generally, the specific gravity of inorganic fine sand reaches 2.5 g / cm³. 3 The density of organic matter in sludge is very close to that of water, typically with a specific gravity of only 1.002–1.003. Based on this characteristic, when the Reynolds number in the separation tank is relatively high, disturbing the sedimentation of light sludge and disrupting the sludge stratification allows fine sand to separate from the organic matter. Therefore, the primary separation tank needs to meet the following functional and structural characteristics:

[0043] (a) The primary separation tank needs to have significant stratification and height, divided into a turbulent zone, a transition zone and a static zone. The Reynolds number in the turbulent zone is relatively large, which is sufficient to disrupt the sludge stratification and sedimentation. It generally needs to be greater than 3000, with a typical value of over 20000. The hydraulic conditions in the transition zone can be provided by the rotational friction force in the turbulent zone. That is, no stirring measures are set in the transition zone. The Reynolds number should be controlled between 2000 and 10, and the Reynolds number gradually decreases from the top to the bottom. There is a certain amount of sludge accumulation in the static zone. Therefore, the sludge accumulated at the bottom of the static zone is in an almost completely static state, and the Reynolds number of the water in the sludge gaps is almost zero.

[0044] (b) The volume ratio of the turbulent zone, transition zone and static zone can generally be controlled at 2:3:5. Generally speaking, the total height needs to be greater than 6 to 8 m. When the hydraulic vortex method is used to achieve circulation in the pool, the diameter-to-depth ratio should not be too large and should not be greater than 0.3.

[0045] (c) In order to reduce the amount of organic matter crossing the transition zone into the bottom stagnant zone, a certain amount of wastewater can be introduced into the transition zone. This will promote upward water flow in the transition zone and dilute the organic sludge sliding down from the upper turbulent zone, thus preventing organic matter from crossing the transition zone due to stratification and sedimentation.

[0046] (d) A method to maintain a high Reynolds number in the turbulent zone is to introduce water along the tangential direction of the pool wall side.

[0047] (2) The small amount of organic sludge is subjected to cell wall breaking treatment using a cell wall breaking machine. The cell wall breaking is performed by mechanical shearing. The broken material then proceeds to the next step of processing. The chemicals added to the cell wall breaking tank are sodium hydroxide and calcium oxide, and the dosage of the chemicals is 6-12% of the dry solids content of the sludge entering the tank.

[0048] (3) The material after cell wall disruption is separated into sludge and sludge in a secondary separation tank. The sludge obtained from the secondary separation is returned to the anoxic tank of the main process, and the obtained secondary sludge is processed in the next step. The main function of the secondary separation tank is to separate fine particulate inorganic matter, and its secondary function is to break down the sludge by adding strong alkaline agents such as sodium hydroxide and calcium oxide to break down the sludge cells. The secondary separation tank adopts a low hydraulic load, with a hydraulic load of <0.3m. 3 / (m 2 •h), and the hydraulic residence time (HRT) > 24h;

[0049] (4) The secondary sludge is separated into tertiary sludge using a tertiary separation tank. The resulting tertiary sludge, after dewatering, has a moisture content of less than 60% and can be transported off-site for disposal. The wastewater obtained is returned to the anoxic tank of the main process. The tertiary separation uses a medium hydraulic load of 0.6–1.0 m. 3 / (m 2 •h) When the organic matter content of the tertiary slag is >20%, cationic PAM is added to the inlet pipe of the tertiary separation tank at a dosage of 0.01-0.03%.

[0050] The primary separation tank uses mechanical stirring, while the secondary separation tank uses either mechanical stirring or air stirring. The main function of the primary and secondary separation tanks is sludge separation, and the main function of the tertiary separation tank is sludge-water separation. The tertiary separation tank is constructed as a sedimentation tank, and the secondary sludge enters the tertiary separation tank after being diluted with wastewater.

[0051] In this embodiment, the raw sludge to be treated first enters the primary separation tank. In the primary separation tank, organic matter (cells, particulate organic matter, etc. in the sludge) and inorganic matter (fine sand, large particles) undergo their first separation. The upper layer of water in the primary separation tank experiences turbulence and pulsation, allowing denser fine particles to separate from less dense organic sludge cells. Ultimately, inorganic particles cross the transition zone and enter the bottom of the primary separation tank, while organic particles, unable to settle, are carried out of the primary separation tank by the water flow. Due to the relatively large height of the primary separation tank, inorganic particles (collectively referred to as "sludge") gradually settle and compress at the bottom, gradually reducing their moisture content. For cases where the inorganic particulate matter content in the wastewater is high, this sludge already meets discharge requirements and can directly bypass subsequent secondary separation and sedimentation, entering the dewatering and transportation stage.

[0052] The upper part of the primary separation tank will discharge low-density activated sludge and particulate organic matter (collectively referred to as "sludge"), while the relatively larger inorganic particles (primary sludge) will naturally settle to the bottom of the tank. If the primary sludge particles are large and contain very little organic matter, they can be directly dewatered.

[0053] Example 2

[0054] like Figure 2 As shown, compared to Example 1, the only difference lies in the entire process of primary slag treatment. The slag treatment process is as follows: primary sludge separation → secondary sludge separation → tertiary separation → concentration → dewatering → transportation. The process includes the following steps:

[0055] (1) The primary separation tank is used to separate the remaining sludge to be treated into primary sludge and sludge. The inorganic particulate sludge in the remaining sludge is separated from the organic sludge. The carbon source loss caused by the discharge of primary sludge affects the carbon source demand of the main process (i.e., the volatile matter ratio of primary sludge is relatively large, generally >20%). Therefore, the primary sludge needs to be further treated. All the organic sludge is returned to the main process, and the primary sludge enters the next step of treatment.

[0056] (2) The small amount of organic sludge or primary residue is subjected to cell wall breaking treatment using a cell wall breaking machine. The cell wall breaking is carried out by mechanical shearing. The material after cell wall breaking is then processed in the next step.

[0057] (3) The material after cell wall breaking is separated into sludge in a secondary separation tank. If the stirring resistance of the secondary separation tank is too high, water should be added for dilution. The sludge obtained from the secondary sludge separation is returned to the anoxic tank of the main process. The secondary sludge is then processed in the next step. The main function of the secondary separation tank is to separate particulate inorganic matter. The secondary function of the secondary separation tank is to break down the sludge. Strong alkaline agents such as sodium hydroxide and calcium oxide are added to break down the sludge cells.

[0058] (4) The secondary sludge is separated into tertiary sludge using a tertiary separation tank. The obtained tertiary sludge is concentrated and dewatered before being transported off-site, and the obtained wastewater is returned to the anoxic tank of the main process.

[0059] like Figure 2 As shown, when the primary slag contains a large amount of organic matter, the primary slag enters the secondary separation stage, and all the primary sludge is recycled. Other aspects are the same as in Example 1.

[0060] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various improvements without departing from the concept of the present invention, and these improvements all fall within the scope of protection of the present invention.

Claims

1. A sludge reduction and resource utilization method based on sludge three-stage separation and cell disruption, characterized in that, Includes the following steps: (1) Use a primary separation tank to separate the remaining sludge to be treated into primary sludge and sludge. The inorganic particles in the remaining sludge are separated from the organic sludge. If the carbon source loss caused by the discharge of the primary sludge does not affect the carbon source requirement of the main process, then 90-95% of the organic sludge is returned to the main process, and 5-10% of the organic sludge is concentrated and then enters the next step of treatment. The primary sludge is concentrated and dewatered and then transported off-site. If the carbon source loss caused by the primary sludge discharge affects the carbon source demand of the main process, then all the organic sludge is recycled to the main process, and the primary sludge enters the next step of treatment; wherein, the main process is a biological nitrogen and phosphorus removal process; the primary separation tank is divided into a turbulent zone, a transition zone and a static zone. The Reynolds number of the turbulent zone is >3000, the Reynolds number of the transition zone is 10~2000, and the Reynolds number in the transition zone gradually decreases from top to bottom. The bottom of the static zone is filled with sludge and is in a static state, and the Reynolds number of the water in the gaps between the sludge is zero; (2) Mechanical cell breaking is used to break down a small amount of organic sludge or primary slag, and the broken material is then processed in the next step. (3) The material after cell wall breaking is separated into sludge in a secondary separation tank. The sludge obtained from the secondary separation is returned to the anoxic tank of the main process, and the secondary residue is processed in the next step. (4) The secondary sludge is separated into tertiary sludge using a tertiary separation tank. The obtained tertiary sludge is concentrated and dewatered before being transported off-site. The obtained wastewater is returned to the anoxic tank of the main process. When the organic matter content of the tertiary sludge is >20%, cationic PAM is added to the inlet pipe of the tertiary separation tank at a dosage of 0.01~0.03%. The primary separation tank employs a high hydraulic loading rate, >20m. 3 / (m 2 •h); The secondary separation tank adopts a low hydraulic load, with a hydraulic load <0.3m. 3 / (m 2 •h), and the hydraulic retention time (HRT) > 24h; the three-stage separation uses a medium hydraulic load of 0.6~1.0m. 3 / (m 2 ·h).

2. The sludge reduction and resource utilization method based on the combined use of three-stage sludge separation and cell disruption as described in claim 1, characterized in that, The volume ratio of the turbulent zone, transition zone, and static zone is 2:3:

5. The total height of the primary separation tank is 6-8m. When the circulation within the tank is achieved using a hydraulic vortex method, the diameter-to-depth ratio is no greater than 0.

3.

3. The sludge reduction and resource utilization method based on the combination of sludge three-stage separation and cell disruption according to claim 1, characterized in that, The primary separation tank uses mechanical stirring, and the secondary separation tank uses mechanical stirring or air stirring.

4. The sludge reduction and resource utilization method based on the combination of sludge three-stage separation and cell disruption according to claim 1, characterized in that, The tertiary separation tank is a sedimentation tank, and the secondary sludge enters the tertiary separation tank after being diluted with sewage.

5. The sludge reduction and resource utilization method based on the combination of sludge three-stage separation and cell disruption according to claim 1, characterized in that, The agents added during the cell wall breaking treatment are sodium hydroxide and calcium oxide, and the dosage of the agents is 6-12% of the dry solids of the sludge entering the tank.

6. The sludge reduction and resource utilization method based on the combined use of three-stage sludge separation and cell disruption as described in claim 1, characterized in that, If the volatile matter content of the primary sludge is relatively low, a small amount of organic sludge will be concentrated before entering the next step of processing. The concentrated organic sludge has a moisture content of 93-95%.

7. The sludge reduction and resource utilization method based on the combination of sludge three-stage separation and cell disruption according to claim 1, characterized in that, The inorganic matter in the remaining sludge has a density greater than that of water, and the specific gravity of the inorganic fine sand is 2.5 g / cm³. 3 The density of organic matter in the remaining sludge is close to that of water, with a specific gravity of 1.002~1.003 g / cm³. 3 .

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