Sludge hydrolysis-AAO operation system

Abstract

The utility model relates to the technical field of sludge treatment, in particular to a sludge hydrolysis-AAO operation system. The system comprises an anaerobic tank, an anoxic tank, an aerobic tank, a precipitation separation tank, a phosphorus release tank, a hydrolysis acidification tank and a reflux tank which are communicated in sequence. The dissolved oxygen concentration of the phosphorus release tank is less than or equal to 0.2 mg / L, the phosphorus release tank is detachably connected with an adsorption module I, and the adsorption module I is filled with a phosphorus adsorbent; a filler layer is detachably connected in the hydrolysis acidification pool, and hydrolytic bacteria and acidification bacteria are embedded and fixed in pores of the filler layer; an adsorption module II is arranged in the reflux tank, the adsorption module II is filled with a phosphorus adsorbent and a nitrogen adsorbent, and the reflux tank is communicated with the anaerobic tank. The residual sludge is degraded to form hydrolytic acidification liquid, after the hydrolytic acidification liquid is absorbed by the adsorption module II, the hydrolytic acidification liquid with low nitrogen and phosphorus content flows back to the anaerobic tank to supplement an internal carbon source, and the system not only can increase the reduction amount of the sludge, but also can fully remove nutrients in the system, so that the effluent meets the first-grade A standard discharge.

Description

Technical Field

[0001] The utility model relates to the technical field of sludge treatment, and more specifically, to a sludge hydrolysis-AAO operation system. Background Art

[0002] Urban sewage treatment plants commonly focus on water over sludge, resulting in approximately 83% of excess sludge being improperly treated. Excess sludge is typically composed of microorganisms and the flocs they form, along with the inorganic and organic matter they adsorb, forming flocs. It also contains pathogens, heavy metals, and other toxic and hazardous substances. The proper treatment of excess sludge is a hot topic in this field.

[0003] Currently, related technologies use sludge hydrolysis and acidification technology to hydrolyze excess sludge or primary sludge, degrading insoluble complex organic matter into small-molecule organic matter. These are then decomposed into internal carbon sources such as volatile acids and esters during the acidification and fermentation process, reducing sludge production and achieving the goal of sludge reduction. However, excess sludge releases nitrogen and phosphorus during hydrolysis and acidification. Directly returning the sludge hydrolysis and acidification liquid with high concentrations of nitrogen and phosphorus to the biological denitrification and phosphorus removal system will further increase the nitrogen and phosphorus load of the influent, making it more difficult for the system to remove nutrients. The effluent quality of the system is poor, making it difficult for the system to meet the Class A emission standards of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB18918-2002). Utility Model Content

[0004] In order to resolve the contradiction between sludge reduction and simultaneous improvement of nutrient removal rate, the present application provides a sludge hydrolysis-AAO operation system.

[0005] This application provides a sludge hydrolysis-AAO operation system, which adopts the following technical solutions:

[0006] A sludge hydrolysis-AAO operation system, comprising:

[0007] Anaerobic tanks;

[0008] an anoxic tank, connected to the anaerobic tank;

[0009] an aerobic tank connected to the anoxic tank;

[0010] A sedimentation and separation tank, connected to the aerobic tank, and provided with a sludge outflow outlet;

[0011] A phosphorus release tank is connected to the sludge outflow port, wherein the dissolved oxygen concentration of the phosphorus release tank is ≤0.2 mg / L, and the phosphorus release tank is detachably connected to an adsorption module 1, which is filled with a phosphorus adsorbent;

[0012] A hydrolysis and acidification tank is connected to the phosphorus release tank, wherein a packing layer is detachably connected to the hydrolysis and acidification tank, and hydrolytic bacteria and acidifying bacteria are embedded and fixed in the pores of the packing layer;

[0013] The reflow tank is connected to the hydrolysis acidification tank. The reflow tank is detachably connected to a second adsorption module filled with a phosphorus adsorbent and a nitrogen adsorbent. The reflow tank is connected to the anaerobic tank.

[0014] By adopting the above technical solution, the present application adds a phosphorus release tank to the traditional AAO system. The dissolved oxygen concentration in the phosphorus release tank is low, and the tank is in an anaerobic state. The polyphosphate bacteria rich in the residual sludge release the phosphorus absorbed in the aerobic tank. The residual sludge passes through the adsorption module 1, and the phosphorus adsorbent absorbs the phosphorus in the residual sludge. The adsorption module 1 is detachably connected, and the phosphorus is removed from the system by replacing the adsorption module 1. At the same time, excessive phosphorus content can easily inhibit the activity of hydrolytic bacteria and acidifying bacteria. Therefore, the hydrolysis and acidification efficiency of the residual sludge with low phosphorus content in the subsequent hydrolysis and acidification tank is improved.

[0015] The low-phosphorus excess sludge undergoes hydrolysis and acidification steps in the hydrolysis and acidification tank. The hydrolytic and acidifying bacteria in the packing layer fully contact the organic matter in the excess sludge, and the organic matter is degraded in the hydrolysis and acidification tank to form an internal carbon source. At the same time, the metabolites produced by the metabolism of microorganisms in the excess sludge also form an internal carbon source, achieving sludge reduction.

[0016] The hydrolysis and acidification liquid produced by the excess sludge flows into the reflow tank and is absorbed by the adsorption module 2 to absorb the nitrogen and phosphorus produced by the hydrolysis and acidification, thereby reducing the impact of the nitrogen and phosphorus produced in the hydrolysis and acidification step on the traditional AAO system and ensuring stable operation of the system.

[0017] The hydrolyzed acidified liquid is returned to the anaerobic tank to provide an internal carbon source to supplement the carbon source required for the subsequent operation of the anaerobic tank, the anoxic tank and the aerobic tank, thereby reducing the addition of nutrients in the system. The system of the present application can not only increase the removal of nutrients and optimize the release of the internal carbon source, but also increase the amount of sludge reduction. The nitrogen and phosphorus content in the final effluent is low, meeting the Class A emission standard of the pollutant discharge standard for urban sewage treatment plants (GB18918-2002).

[0018] Furthermore, the reflow tank is provided with a first sludge reflow point and a second sludge reflow point, the first sludge reflow point is connected to the anaerobic tank, and the second sludge reflow point is connected to the anoxic tank.

[0019] Furthermore, the sludge return ratio of the first sludge return point is 5% to 10%, and the sludge return ratio of the second sludge return point is 40% to 50%.

[0020] By adopting the above technical solution, the setting of two sludge return points can adjust the sludge return position, thereby adapting to the high load and low sludge age requirements of the anaerobic tank and the low load and high sludge age requirements of the anoxic tank.

[0021] Furthermore, the drainage outlet of the water distribution pipe is located in the packing layer.

[0022] Furthermore, the distribution position of the water distribution pipe is not higher than 1 / 3 of the height of the packing layer.

[0023] By adopting this technical solution, the water from the outlet flows within the pore structure of the packing layer, driving the flow of excess sludge within the packing layer. This ensures efficient degradation of the excess sludge while reducing the possibility of clogging the packing layer pores. The low height of the water distribution pipe minimizes the impact on the decomposition and conversion of hydrolytic and acidifying bacteria in the middle and top of the packing layer, thereby ensuring the efficient decomposition and conversion of excess sludge in the hydrolysis and acidification tanks.

[0024] Furthermore, the adsorption module 1 includes a first frame and a first biochar grid plate, the first biochar grid plate is fixed in the first frame, and the gap structure of the first biochar grid plate is larger than the particle size of the excess sludge.

[0025] By adopting the above technical solution, the main component of the first biochar grating plate is biochar, which is pressed and formed by biochar and can absorb phosphorus, nitrogen and other substances released by the residual sludge; the first biochar grating plate has a large gap structure and can fully absorb the phosphorus released by the residual sludge without affecting the residual sludge entering the hydrolysis and acidification tank.

[0026] Furthermore, a power part and a rotating base are provided in the phosphorus release pool, the first frame is connected to the rotating base, and the power part drives the rotating base to rotate.

[0027] By adopting the above technical solution, the rotating base drives the frame to rotate, and the remaining sludge hits the adsorption module 1 and is broken, which is conducive to degradation in the filler layer with smaller particle size in the later stage and improves the degradation rate.

[0028] Furthermore, the sum of the areas of the bars in the first biochar grid plate is 20% to 30% of the total area of ​​the first biochar grid plate.

[0029] By adopting the above technical solution, the area ratio of the bars in the first biochar grid plate is optimized, thereby taking into account both the phosphorus removal efficiency and the passing efficiency of the residual sludge.

[0030] Furthermore, the adsorption module 2 includes a frame including a second frame and a second biochar grid plate, the second biochar grid plate is fixed in the second frame, and the gap structure of the second biochar grid plate is larger than the particle size of the excess sludge.

[0031] By adopting the above technical solution, the second biochar grid is used in the adsorption module 2 as a nitrogen and phosphorus adsorbent, and the nitrogen and phosphorus in the hydrolyzed acidified liquid are adsorbed, thereby reducing the nitrogen and phosphorus content in the hydrolyzed acidified liquid and ensuring that the remaining sludge passes through the gaps in the second biochar grid and flows back to the anaerobic tank or the anoxic tank.

[0032] In summary, this application has at least the following advantages:

[0033] First, this system converts excess sludge into endogenous carbon through the coordination of the phosphorus release tank, hydrolysis acidification tank, and reflow tank, replenishing the nutrients required for system operation. This can not only increase the amount of sludge reduction by more than 35%, but also reduce the amount of external carbon source added by at least 50%.

[0034] Second, the system reduces the amount of nutrients entering the anaerobic tank during the hydrolysis and acidification process of excess sludge, optimizing the release of internal carbon sources to over 1500 mg / L.

[0035] Third, this application overcomes the defect of the traditional AAO mode that focuses on only one aspect of nitrogen removal and phosphorus removal, and can achieve simultaneous and efficient nitrogen removal and phosphorus removal. After the operation of the system, the effluent water quality reaches the level of Class A of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB18918-2002). BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the specific structure of a sludge hydrolysis-AAO operation system disclosed in Example 1.

[0037] Figure 2 This is a schematic diagram of the cross-sectional structure along the AA direction in Example 1.

[0038] Reference numerals:

[0039] 1. Anaerobic tank; 2. Anoxic tank; 3. Aerobic tank; 4. Sedimentation and separation tank; 5. Phosphorus release tank; 6. Hydrolysis and acidification tank; 7. Return tank; 8. Sewage inlet point; 9. Hydrolysis and acidification liquid inflow point; 10. First sludge return point; 11. Second sludge return point; 12. Return water tank; 13. Sludge outflow port; 14. Rotating base; 15. Power parts; 16. Adsorption module 1; 17. First frame; 18. First biochar grid plate; 19. Mud and water pipeline; 20. Water distribution pipe; 21. Filling layer; 22. Mud discharge pipe; 23. Adsorption module 2; 24. Second frame; 25. Second biochar grid plate. DETAILED DESCRIPTION

[0040] Example 1

[0041] A sludge hydrolysis-AAO operation system includes an anaerobic tank 1, an anoxic tank 2, an aerobic tank 3, a sedimentation and separation tank 4, a phosphorus release tank 5, a hydrolysis and acidification tank 6, and a reflow tank 7, which are connected in sequence. The present application utilizes the additional phosphorus release tank 5, hydrolysis and acidification tank 6, and reflow tank 7 to degrade the excess sludge separated from the sedimentation and separation tank 4. Part of the excess sludge is converted into endogenous carbon, which flows back into the anaerobic tank 1 along with the hydrolysis and acidification liquid. This system simultaneously reduces the nitrogen and phosphorus content in the hydrolysis and acidification liquid, and the hydrolysis and acidification liquid flows back into the anaerobic tank 1. This system can simultaneously achieve efficient reduction of excess sludge and efficient removal of nutrients from wastewater.

[0042] See also Figure 1 A sewage inlet point 8 is provided between the anaerobic tank 1, the anoxic tank 2, the aerobic tank 3, and the sedimentation and separation tank 4, so that sewage can flow through the anaerobic tank 1, the anoxic tank 2, the aerobic tank 3, and the sedimentation and separation tank 4 in sequence, thereby achieving the goals of nitrogen removal, phosphorus removal, and nutrient removal. A valve (not shown in the figure) is installed in the sewage inlet point 8, and the inlet concentration of the sewage can be adjusted by adjusting the opening of the valve. The dissolved oxygen concentration of the anaerobic tank 1 is controlled to be below 0.2 mg / L. The activated sludge in the anaerobic tank 1 contains phosphate-accumulating bacteria, which consume carbon sources and release phosphorus.

[0043] See also Figure 1 The anaerobic tank 1 is provided with a hydrolysis and acidification liquid inflow point 9, which connects the anaerobic tank 1 and the recirculation tank 7. The carbon source in the anaerobic tank 1 comes from the exogenous carbon introduced by the sewage and the internal carbon source introduced by the hydrolysis and acidification liquid inflow point 9. The anaerobic tank 1 is also provided with a first sludge reflow point 10. The first sludge reflow point 10 can transport the excess sludge in the recirculation tank 7 to the anaerobic tank 1 via a screw conveyor or other means to replenish the activated sludge in the anaerobic tank 1. The reflow ratio of the first sludge reflow point 10 is controlled to 5% to 10% to ensure that the reflow of the excess sludge does not affect the activity of the polyphosphate bacteria.

[0044] See also Figure 1 , the dissolved oxygen concentration of the anoxic tank 2 is controlled to be 0.2-0.5 mg / L, and the denitrifying bacteria in the anoxic tank 2 absorb nitrogen-containing substances such as nitrate and ammonia, and convert them into nitrogen gas, completing the denitrification process. A second sludge return point 11 is provided on the anoxic tank 2. The second sludge return point 11 can transport the residual sludge in the return tank 7 to the anaerobic tank 1 through a screw conveyor or the like, thereby increasing the high-sludge-age activated sludge in the anoxic tank 2. At the same time, a return water tank 12 is provided between the anoxic tank 2 and the sedimentation separation tank 4. The return water tank 12 returns the qualified effluent from the sedimentation separation tank 4 to the anoxic tank 2. The water return ratio of the return water tank 12 is 60%-80%, which meets the low-load and high-sludge-age operation requirements of the anoxic tank 2.

[0045] See also Figure 1The dissolved oxygen concentration in aerobic tank 3 is above 2 mg / L. The phosphate-accumulating bacteria in aerobic tank 3 consume nutrients such as exogenous and endogenous carbon and absorb phosphorus in the wastewater, thereby achieving the purpose of phosphorus removal. The wastewater that has completed nitrogen and phosphorus removal enters the sedimentation and separation tank 4 for static separation.

[0046] See also Figure 1 The sedimentation and separation tank 4 is provided with a sludge outlet 13, which can transport the excess sludge in the sedimentation and separation tank 4 to the phosphorus release tank 5 via a screw conveyor or other means. The dissolved oxygen concentration in the phosphorus release tank 5 is controlled to be below 0.2 mg / L. A small amount of waste molasses is added to the phosphorus release tank 5 as a carbon source to promote the release of phosphorus by the polyphosphate bacteria. The phosphorus is dissolved in the water in the form of phosphate radicals, thereby obtaining a high-concentration phosphorus-containing mixed solution.

[0047] See also Figure 1 and Figure 2 , a rotating base 14 and a power part 15 are fixed in the phosphorus release pool 5, and an adsorption module 16 is installed on the rotating base 14. The adsorption module 16 includes a first frame 17 and a plurality of first biochar grating plates 18. The first biochar grating plates 18 are made of pressed and solidified biochar. Biochar, as a phosphorus adsorbent, can absorb phosphate. The first frame 17 can realize the connection between the adsorption module 16 and the rotating base 14 by means of detachable connections such as bolting and magnetic attraction. Regularly disassembling the adsorption module 16 can remove phosphorus in the system. The power part 15 drives the rotating base 14 to rotate, and the rotating base 14 drives the adsorption module 16 to rotate, crushing the residual sludge, so that the large-particle residual sludge is crushed into small-particle residual sludge.

[0048] See also Figure 1 and Figure 2 A mud and water pipe 19 is provided between the phosphorus release tank 5 and the hydrolysis and acidification tank 6, and the residual sludge is pumped into the hydrolysis and acidification tank 6 through the mud and water pipe 19. A packing layer 21 is installed in the hydrolysis and acidification tank 6, and hydrolytic bacteria and acidifying bacteria are embedded and fixed in the packing layer 21. The mud and water pipe 19 and the water distribution pipe 20 are both provided in the packing layer 21. The mud and water pipe 19 and the water distribution pipe 20 are located at the bottom of the packing layer 21, not exceeding 1 / 3 of its height. Under the action of the water flow in the water distribution pipe 20, the residual sludge moves slowly in the pore structure of the packing layer 21 until it is discharged from the top of the packing layer 21 and settles to the bottom of the hydrolysis and acidification tank 6. Part of the residual sludge continues to flow into the reflow tank 7, and then returns to the anaerobic tank 1, while the remaining residual sludge is discharged through the mud discharge pipe 22 provided at the bottom of the hydrolysis and acidification tank 6.

[0049] See also Figure 1 and Figure 2The hydrolysis-acidification liquid produced at the top of the hydrolysis-acidification tank 6 flows into the recirculation tank 7. Adsorption module 23 is installed within the recirculation tank 7. Adsorption module 23 comprises a second frame 24 and a second biochar grating 25. The second biochar grating 25 is made of compressed and solidified biochar. Biochar also acts as a nitrogen adsorbent, absorbing phosphate, nitrate, and ammonia, thereby reducing the nitrogen and phosphorus content in the hydrolysis-acidification liquid. The second frame 24 can be fixed to the wall of the recirculation tank 7 using a removable connection such as bolting. The second biochar grating 25 is periodically replaced to reduce the overall nitrogen and phosphorus content in the system.

[0050] Wastewater is introduced into this system, and the wastewater indicators are as follows: COD concentration 10360-12570 mg / L, BOD concentration 6230-7680 mg / L, total N content 230-490 mg / L, total phosphorus content 105-220 mg / L, pH 5.3-7.2;

[0051] After the system had been running continuously for 14 days, the effluent was tested and the COD concentration, SS concentration, BOD concentration, total N content, and total phosphorus content were less than 0.35 mg / L, respectively. The effluent quality met the requirements of Level A of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB18918-2002).

[0052] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] Furthermore, the above-described embodiments merely represent several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent. It should be noted that a person of ordinary skill in the art can make a number of variations and improvements without departing from the concept of the present invention, and these variations and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be based on the appended claims.

Claims

1. A sludge hydrolysis-AAO operation system, comprising: Anaerobic tank (1); An anoxic tank (2), connected to the anaerobic tank (1); an aerobic tank (3) connected to the anoxic tank (2); A sedimentation separation tank (4) is connected to the aerobic tank (3) and is provided with a sludge outflow outlet (13); The invention is characterized in that: the phosphorus release pool (5) is connected to the sludge outflow outlet (13), the dissolved oxygen concentration of the phosphorus release pool (5) is ≤0.2 mg / L, the phosphorus release pool (5) is detachably connected to an adsorption module (16), and the adsorption module (16) is filled with a phosphorus adsorbent; A hydrolysis and acidification tank (6) is connected to the phosphorus release tank (5), wherein a packing layer (21) is detachably connected to the hydrolysis and acidification tank (6), and hydrolytic bacteria and acidifying bacteria are embedded and fixed in the pores of the packing layer (21); The reflow tank (7) is connected to the hydrolysis acidification tank (6). The reflow tank (7) is detachably connected to the adsorption module 2 (23). The adsorption module 2 (23) is filled with a phosphorus adsorbent and a nitrogen adsorbent. The reflow tank (7) is connected to the anaerobic tank (1).

2. The sludge hydrolysis-AAO operation system according to claim 1, characterized in that: The reflow tank (7) is provided with a first sludge reflow point (10) and a second sludge reflow point (11), wherein the first sludge reflow point (10) is connected to the anaerobic tank (1), and the second sludge reflow point (11) is connected to the anoxic tank (2).

3. The sludge hydrolysis-AAO operation system according to claim 2, characterized in that: The sludge return ratio of the first sludge return point (10) is 5% to 10%, and the sludge return ratio of the second sludge return point (11) is 40% to 50%.

4. The sludge hydrolysis-AAO operation system according to claim 1, characterized in that: The drainage port of the water distribution pipe (20) is located in the filler layer (21).

5. The sludge hydrolysis-AAO operation system according to claim 4, characterized in that: The distribution position of the water distribution pipe (20) is no higher than 1 / 3 of the height of the packing layer (21).

6. The sludge hydrolysis-AAO operation system according to claim 1, characterized in that: The adsorption module 1 (16) includes a first frame (17) and a first biochar grid plate (18), wherein the first biochar grid plate (18) is fixed in the first frame (17), and the gap structure of the first biochar grid plate (18) is larger than the particle size of the residual sludge.

7. The sludge hydrolysis-AAO operation system according to claim 6, characterized in that: A power piece (15) and a rotating base (14) are provided in the phosphorus release pool (5); the first frame (17) is connected to the rotating base (14); and the power piece (15) drives the rotating base (14) to rotate.

8. The sludge hydrolysis-AAO operation system according to claim 7, characterized in that: The sum of the areas of the bars in the first biochar grid plate (18) is 20% to 30% of the total area of ​​the first biochar grid plate (18).

9. The sludge hydrolysis-AAO operation system according to claim 1, characterized in that: The adsorption module 2 (23) includes a frame including a second frame (24) and a second biochar grid plate (25), the second biochar grid plate (25) is fixed in the second frame (24), and the gap structure of the second biochar grid plate (25) is larger than the particle size of the residual sludge.

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