An old oxidation ditch pool reconstruction multiplication type AAO biochemical pool

Abstract

This utility model relates to the field of biological treatment tank technology, specifically to a multiplier-type AAO biological treatment tank for the renovation of existing oxidation ditch tanks. It includes an oxidation ditch body and an outer tank wall, with an anaerobic zone and an aerobic zone within the outer tank wall. Adjacent to the aerobic zone in the anaerobic zone are sequentially arranged a first anoxic zone and a second anoxic zone. The aerobic zone, excluding the anaerobic zone, is equipped with multiple partition walls, and between adjacent partition walls are respectively arranged a multi-functional zone, a pre-sedimentation zone, a first low-oxygen zone, a second low-oxygen zone, and an enhanced aeration zone. This invention solves the technical problem of difficulty in doubling the unit tank volume treatment capacity and efficiency of existing wastewater treatment plant oxidation ditch biological treatment tanks; it solves the technical problem of not damaging the civil engineering structure and not excessively increasing the load-bearing capacity of the bottom slab during the renovation of existing wastewater treatment plant oxidation ditch biological treatment tanks; it solves the technical problem of low nitrogen removal efficiency in existing wastewater treatment plant oxidation ditches; and it solves the problem of difficulty in energy saving and consumption reduction in existing wastewater treatment plant oxidation ditch processes.

Description

Technical Field

[0001] This utility model relates to the field of biochemical tank technology, specifically to a multiplier type AAO biochemical tank that utilizes existing oxidation ditch tanks. Background Technology

[0002] Traditional oxidation ditches are constructed as closed, ring-shaped channels. During operation, wastewater and activated sludge continuously circulate within the aeration channels, resulting in delayed aeration, a long hydraulic retention time, relatively low load, and relatively stable effluent. However, their disadvantages are also quite significant, mainly in the following aspects:

[0003] 1. Large footprint: Oxidation ditches are usually designed as ring ditches, which rely on a long hydraulic retention time (HRT), resulting in a large volume of structures.

[0004] 2. High energy consumption: Surface aerators (such as rotating brushes and discs) or underwater propulsion devices need to operate continuously to maintain mixing and oxygen transfer.

[0005] 3. Low nitrogen removal efficiency: It relies on alternating aerobic / anoxic zones within the ditch, but the denitrification efficiency is limited by the carbon source and internal recirculation.

[0006] 4. Insufficient flexibility: There is limited room for structural adjustment when expanding capacity or upgrading processes.

[0007] 5. High maintenance costs: Mechanical components such as aeration equipment and underwater propulsion devices require regular inspections, resulting in high long-term maintenance costs. Utility Model Content

[0008] To address the aforementioned shortcomings of existing technologies, this invention provides a multiplier-type AAO biochemical tank that utilizes existing oxidation ditch ponds, effectively solving problems such as large footprint, high energy consumption, and low nitrogen removal efficiency in existing technologies.

[0009] To achieve the above objectives, this utility model provides the following technical solution:

[0010] This utility model provides a method for transforming an existing oxidation ditch into a multiplier AAO biological treatment tank, comprising an oxidation ditch body and an outer tank wall, characterized in that it further includes:

[0011] The outer pool wall is provided with anaerobic and aerobic zones;

[0012] The anaerobic zone is adjacent to the aerobic zone and the area is sequentially divided into a first hypoxic zone and a second hypoxic zone.

[0013] The aerobic zone, excluding the aerobic zone, is equipped with multiple partition walls. Between the adjacent partition walls, there are a multi-functional zone, a pre-sedimentation zone, a first low-oxygen zone, a second low-oxygen zone, and an enhanced aeration zone.

[0014] Furthermore, the oxidation ditch body is provided with a fifth partition wall, and the anaerobic zone is the area between the fifth partition wall and the outer pool wall.

[0015] Furthermore, the oxidation ditch body is provided with a first partition wall, a second partition wall, a third partition wall and a fourth partition wall, which together form a first aerobic zone.

[0016] Furthermore, a sixth partition wall and an eighth partition wall are provided in the oxidation ditch body, and a first anoxic zone is formed by the second partition wall, the sixth partition wall, the eighth partition wall and the outer pool wall.

[0017] Furthermore, the oxidation ditch body is provided with a third partition wall, a fourth partition wall, a tenth partition wall, an eleventh partition wall, and a high solids interception device, and a second anoxic zone is formed through the eighth partition wall, the tenth partition wall, the eleventh partition wall, and the high solids interception device.

[0018] Furthermore, a high-solids-intercepting mud-water separation device is provided in the oxidation ditch body, and a first low-oxygen zone is formed by the first partition wall, the third partition wall and the high-solids-intercepting mud-water separation device.

[0019] Furthermore, the oxidation ditch body is provided with thirteen partition walls, forming a multi-functional area through the fourth, fifth, eleventh and thirteenth partition walls.

[0020] Furthermore, a second low-oxygen zone is formed by the first partition wall, the sixth partition wall, the thirteenth partition wall, and the outer pool wall.

[0021] Furthermore, a pre-settling zone is provided at the high-solids interception mud-water separation device.

[0022] Furthermore, the oxidation ditch body is provided with a ninth partition wall and a fifteenth partition wall, a first gas lift is provided at the ninth partition wall, and an anaerobic gas lift is provided at the fifteenth partition wall.

[0023] The technical solution provided by this utility model has the following advantages compared with the known prior art:

[0024] 1. It solved the technical problem of doubling the treatment capacity and efficiency of the oxidation ditch biochemical tank in existing sewage treatment plants.

[0025] 2. It solved the technical problem of not damaging the civil engineering structure and not excessively increasing the load-bearing capacity of the bottom slab during the renovation of the oxidation ditch biochemical pool of the existing sewage treatment plant.

[0026] 3. It solved the technical problem of low nitrogen removal efficiency in oxidation ditches of existing sewage treatment plants.

[0027] 4. It solved the problem of energy saving and consumption reduction in the oxidation ditch process of existing sewage treatment plants. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall design of this utility model;

[0030] Figure 2 This is the planar layout for the traditional oxidation ditch process.

[0031] The labels in the diagram represent: 1. First partition wall; 2. Second partition wall; 3. Third partition wall; 4. Fourth partition wall; 5. Fifth partition wall; 6. Sixth partition wall; 7. Seventh partition wall; 8. Eighth partition wall; 9. Ninth partition wall; 10. Tenth partition wall; 11. Eleventh partition wall; 12. Twelfth partition wall; 13. Thirteenth partition wall; 14. High-solids interception pre-settling device; 15. High-solids interception mud-water separation device. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0033] The present invention will be further described below with reference to the embodiments.

[0034] Example: A type of AAO biological treatment tank that utilizes an existing oxidation ditch for transformation, including the oxidation ditch body and the outer tank wall, and the outer tank wall is provided with an anaerobic zone and an aerobic zone;

[0035] The areas adjacent to the anaerobic zone are sequentially designated as the first and second anoxic zones.

[0036] The aerobic zone is surrounded by multiple partitions, with adjacent partitions forming a multi-functional zone, a pre-sedimentation zone, a first low-oxygen zone, a second low-oxygen zone, and an enhanced aeration zone.

[0037] The oxidation ditch body contains a fifth partition wall 5. The anaerobic zone is the area between the fifth partition wall 5 and the outer pool wall. The oxidation ditch body also contains a first partition wall 1, a second partition wall, a third partition wall 3, and a fourth partition wall 4, which together form the first aerobic zone. The oxidation ditch body also contains a sixth partition wall 6 and an eighth partition wall 8, which together form the first anoxic zone with the second partition wall 2, the sixth partition wall 6, the eighth partition wall 8, and the outer pool wall. The oxidation ditch body also contains a third partition wall 3, a fourth partition wall 4, a tenth partition wall 10, an eleventh partition wall 11, and a high-solids interception device 14. These partition walls together form the first anoxic zone. The high-solids interception device 11 and the high-solids interception mud-water separation device 14 form a second anoxic zone. The oxidation ditch body is equipped with a high-solids interception mud-water separation device 15. The first low-oxygen zone is formed by the first partition wall 1, the third partition wall 3 and the high-solids interception mud-water separation device 15. The oxidation ditch body is equipped with a thirteenth partition wall 13. The fourth partition wall 4, the fifth partition wall 5, the eleventh partition wall 11 and the thirteenth partition wall 13 form a multi-functional zone. The second low-oxygen zone is formed by the first partition wall 1, the sixth partition wall 6, the thirteenth partition wall 13 and the outer pool wall. A pre-sedimentation zone is set at the high-solids interception mud-water separation device 15. The oxidation ditch body is equipped with a ninth partition wall 9 and a fifteenth partition wall. The ninth partition wall 9 is equipped with a first air lift and the fifteenth partition wall is equipped with an anaerobic air lift.

[0038] like Figure 2 As shown: In a traditional oxidation ditch, the anaerobic zone is formed by the outer pool wall and the fifth partition wall. The first partition wall 1 and the fourth partition wall 4, together with the second partition wall 2, the third partition wall 3 and the fifth partition wall 5, form the first aerobic zone. The second aerobic zone is formed by the first partition wall 1 and the fifth partition wall 5 and the outer pool wall.

[0039] like Figure 1 As shown: The multiplier oxidation ditch type AAO reactor of this invention retains the original traditional oxidation ditch, where the anaerobic zone is formed by the outer pool wall and the fifth partition wall 5; by adding the sixth partition wall 6 and the eighth partition wall 8, a first anoxic zone is formed by the original oxidation ditch's second partition wall 2 and the outer pool wall; by adding the eighth partition wall 8, the tenth partition wall 10, the eleventh partition wall 11, and the newly added high-solids interception device 14, a second anoxic zone is formed by the original oxidation ditch's fourth partition wall 4 and third partition wall 3; by adding the original oxidation ditch's first partition wall 1, the third partition wall 3, and the newly added high-solids interception device 14, a second anoxic zone is formed by the original oxidation ditch's first partition wall 1, the third partition wall 3, and the newly added high-solids interception device 14. The solid-liquid separation device 14 and the newly added eleventh partition wall 11 form the first low-oxygen zone; the newly added eleventh partition wall 11 and thirteenth partition wall 13, together with the original fourth oxidation partition wall 4 and fifth partition wall 5, form a multi-functional zone; the newly added thirteenth partition wall 13 and sixth partition wall 6, together with the original first oxidation partition wall 1 and the outer pool wall, form the second low-oxygen zone; the newly added high-solids-retention solid-liquid separation device 14 forms the pre-sedimentation zone; the newly added ninth partition wall 9 forms the first air lift; and the newly added fifteenth partition wall forms the anaerobic air lift.

[0040] The working principle of the multiplication oxidation ditch type AAO reactor of this invention is as follows:

[0041] The wastewater entering the first anoxic zone is first completely mixed with the nitrified liquid returned from the second hypoxic zone via an axial flow pump and the returned sludge lifted by the sedimentation airlift from the newly added pre-sedimentation tank at the front end of the first anoxic zone.

[0042] The sludge-water mixture after denitrification in the first anoxic zone is then propelled by anaerobic lift and reflux nitrification liquid axial flow pumps, respectively, into the anaerobic and second anoxic zones. The free oxygen in the sludge-water mixture after denitrification and denitrification in the first anoxic zone is almost completely eliminated, and the combined oxygen is also significantly reduced. This provides extremely favorable preconditions for creating the optimal anaerobic and anoxic metabolic environment for subsequent entry into the anaerobic and second anoxic zones. This invention employs a parallel design for the anaerobic and second anoxic zones, abandoning the traditional design of connecting them in series. This avoids the mutual constraints caused by the increased reflux ratios in the anaerobic and anoxic zones, which would reduce the effective reaction time of each functional zone and consequently affect the denitrification and phosphorus removal efficiency.

[0043] The sludge-water mixture after complete phosphorus release in the anaerobic zone and after complete denitrification in the second anoxic zone are driven by anaerobic lift and reflux nitrification liquid axial flow pumps, respectively, and then enter the front end of the multifunctional zone for complete mixing. In this invention, perforated stirring tubes are preferentially used for sludge-water mixing in the first anoxic zone, anaerobic zone, and second anoxic zone, thus eliminating the need for the high-energy-consuming underwater propulsion and stirring mechanical power equipment relied upon in traditional anaerobic and anoxic zones.

[0044] Because the multi-functional zone employs a design that couples perforated stirring pipes with microporous aeration equipment, it provides an essential prerequisite for this functional zone to freely switch between anoxic and aerobic conditions according to changes in operating conditions. This greatly enhances the multiplier oxidation ditch-type AAO reactor transformed from an existing oxidation ditch biological treatment tank, giving it a strong ability to correct deviations from secondary design loads and ensuring stable, year-round compliant discharge of effluent, providing a powerful guarantee. Microorganisms can partially absorb excess phosphorus and remove some organic matter here before entering the front end of the second low-oxygen zone. There, they completely mix with the sludge-water mixture from the end of the second low-oxygen zone, which has been lifted by the first airlift. After this complete low-oxygen biological metabolism, a portion of the sludge-water mixture from the second low-oxygen zone flows by gravity into the subsequent enhanced aeration zone. Organic matter, total phosphorus, and ammonia nitrogen in the wastewater are discharged in compliance with standards here before entering the pre-sedimentation tank for sludge pre-retention.

[0045] After the sludge is pre-intercepted through the pre-sedimentation area, it is all lifted back to the first anoxic zone by air lift and then participates in the anaerobic phosphorus release in the subsequent anaerobic zone. The effluent containing sludge after pre-intercepted sedimentation and water separation (it is advisable to control the effluent MLSS ≤ 2000 mg / l) is collected through the effluent collection device at the top and then discharged into the secondary sedimentation tank of the original oxidation ditch. The sludge separated from the water through the secondary sedimentation tank is discharged as excess sludge and does not need to be refluxed to the retrofitted multiplied oxidation ditch type AAO reactor unless necessary. The pre-sedimentation tank of the present invention is preferably designed by adopting the design method of inclined tube sedimentation. And the inclined tube packing is preferably selected with a pore diameter of 80 - 90 mm, a wall thickness of 0.8 - 1 mm, and an inclined length between 1 - 3 m. Therefore, the inclined tube sedimentation tank designed in this way can completely replace the MBR membrane filtration and achieve a high sludge concentration operation equivalent to the MBR process of 5 - 12 g / l. Therefore, it can double the treatment capacity and treatment efficiency per unit tank volume of the retrofitted biochemical tank, meet the requirements of the in-situ upgrading and capacity expansion of the traditional oxidation ditch biochemical tank, and at the same time reduce the solid flux of the original oxidation ditch supporting circular secondary sedimentation tank and improve the sedimentation and water separation effect of the original circular secondary sedimentation tank. In special cases, phosphorus removal agents can also be directly added to the pre-sedimented effluent. While ensuring the stable compliance of the total phosphorus in the sewage treatment plant, it can also avoid the return of the physical and chemical sludge containing phosphorus removal agents to the front-end oxidation ditch reaction tank and affect the sludge activity of the oxidation ditch.

[0046] To sum up, through the above transformation, the present invention can completely transform the traditional oxidation ditch process into a multiplied oxidation ditch type AAO reactor, thereby doubling the treatment capacity and treatment efficiency per unit tank volume of the retrofitted oxidation ditch biochemical tank and meeting the requirements of the in-situ upgrading and capacity expansion of the traditional oxidation ditch biochemical tank. It can also achieve the green and low-carbon operation of the retrofitted oxidation ditch biochemical tank with "pure gas drive and zero underwater mechanical power".

[0047] The multiplied AAO process is based on the unchanged anaerobic, anoxic and aerobic functional zoning of the traditional AAO process. By integrating the low dissolved oxygen, high sludge concentration, integrated structure and large-scale air lift reflux dilution of the low-oxygen biological multiplication process, the finally improved traditional AAO process (i.e., the multiplied AAO) can completely replace the high sludge concentration MBBR or MBR process in the same field in terms of function, so as to double the treatment capacity and treatment efficiency per unit tank volume of the traditional activated sludge process.

[0048] Due to the lack of distinct anoxic and aerobic functional zones in the traditional oxidation ditch process and mostly circular sedimentation design methods, how to make use of the existing oxidation ditch biochemical tank and how to achieve that the traditional oxidation ditch biochemical tank after in-situ transformation can reach the functions of the multiplied AAO process, so as to double the treatment capacity and treatment efficiency per unit tank volume of the traditional oxidation ditch biochemical tank after transformation to meet the market demand for the in-situ upgrading and capacity expansion of the traditional oxidation ditch biochemical tank in existing sewage treatment plants.

[0049] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of this utility model.

Claims

1. A method for transforming an existing oxidation ditch into a multiplier-type AAO biological treatment tank, comprising an oxidation ditch body and an outer tank wall, characterized in that, Also includes: The outer pool wall is provided with anaerobic and aerobic zones; The anaerobic zone is adjacent to the aerobic zone and the area is sequentially divided into a first hypoxic zone and a second hypoxic zone. The aerobic zone, excluding the aerobic zone, is equipped with multiple partition walls. Between the adjacent partition walls, there are a multi-functional zone, a pre-sedimentation zone, a first low-oxygen zone, a second low-oxygen zone, and an enhanced aeration zone.

2. The AAO biological treatment tank for transforming an existing oxidation ditch into a multiplier type as described in claim 1, characterized in that, The oxidation ditch body is provided with a fifth partition wall (5), and the anaerobic zone is the area between the fifth partition wall (5) and the outer pool wall.

3. The AAO biological treatment tank for transforming an existing oxidation ditch into a multiplier type as described in claim 2, characterized in that, The oxidation ditch body is provided with a first partition wall (1), a second partition wall, a third partition wall (3) and a fourth partition wall (4), which together form the first aerobic zone.

4. The AAO biological treatment tank for transforming an existing oxidation ditch into a multiplier type as described in claim 3, characterized in that, The oxidation ditch body is provided with a sixth partition wall (6) and an eighth partition wall (8), and a first anoxic zone is formed by the second partition wall (2), the sixth partition wall (6), the eighth partition wall (8) and the outer pool wall.

5. The AAO biological treatment tank for transforming an existing oxidation ditch into a multiplier type as described in claim 4, characterized in that, The oxidation ditch body is provided with a third partition wall (3), a fourth partition wall (4), a tenth partition wall (10), an eleventh partition wall (11) and a high solids interception device (14), and a second anoxic zone is formed by the eighth partition wall (8), the tenth partition wall (10), the eleventh partition wall (11) and the high solids interception device (14).

6. The AAO biological treatment tank for transforming an existing oxidation ditch into a multiplier type as described in claim 5, characterized in that, The oxidation ditch body is equipped with a high solids interception mud-water separation device (15), and a first low-oxygen zone is formed by the first partition wall (1), the third partition wall (3) and the high solids interception mud-water separation device (15).

7. The AAO biological treatment tank for transforming an existing oxidation ditch into a multiplier type as described in claim 6, characterized in that, The oxidation ditch body is provided with thirteen partition walls (13), and a multi-functional area is formed by the fourth partition wall (4), the fifth partition wall (5), the eleventh partition wall (11) and the thirteenth partition wall (13).

8. The AAO biological treatment tank for transforming an existing oxidation ditch into a multiplier type as described in claim 7, characterized in that, A second low-oxygen zone is formed by the first partition wall (1), the sixth partition wall (6), the thirteenth partition wall (13), and the outer pool wall.

9. The AAO biological treatment tank for transforming an existing oxidation ditch into a multiplier type as described in claim 8, characterized in that, A pre-settling zone is provided at the high-solids interception mud-water separation device (15).

10. The AAO biological treatment tank for transforming an existing oxidation ditch into a multiplier type as described in claim 9, characterized in that, The oxidation ditch body is provided with a ninth partition wall (9) and a fifteenth partition wall. The ninth partition wall (9) is provided with a first gas lift, and the fifteenth partition wall is provided with an anaerobic gas lift.

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