Biological contact oxidation process and system

Abstract

This disclosure provides a biological contact oxidation method and system, applied in the field of water pollution control and treatment technology. The method includes: introducing wastewater into the reaction tank of a biological contact oxidation system, and treating the wastewater based on iron-carbon packing material and activated sludge in the reaction tank; wherein, the microorganisms in the iron-carbon packing material and activated sludge undergo a coupled reaction to jointly treat the wastewater. The biological contact oxidation method and system provided by this disclosure utilizes the acidic biofilm formed by microorganisms on the surface of the iron-carbon packing material to provide an acidic environment, promoting micro-electrolysis. The decomposed iron ions can enhance the settling performance of the activated sludge, strengthening the phosphorus removal effect of the wastewater. Activated carbon can adsorb pollutants in the wastewater, improving the wastewater purification effect. The iron-carbon packing material promotes short-range nitrification and denitrification of microorganisms, requires low aeration, and is beneficial for energy saving and consumption reduction. The entire process does not require the addition of acid or alkali reagents, simplifying the process while avoiding any impact on the wastewater purification effect.

Description

Technical Field

[0001] This disclosure relates to the field of water pollution control and treatment technology, and more specifically, to a biological contact oxidation method and system. Background Technology

[0002] Adding various chemicals or fillers to wastewater to reduce pollutant concentrations is a commonly used water treatment technology. Common water treatment fillers include ceramsite, soft fillers, semi-soft fillers, and elastic three-dimensional fillers, all of which aim to increase the biofilm formation of microorganisms, thereby improving water treatment efficiency by increasing the amount of microorganisms per unit area.

[0003] Existing studies have found that iron-carbon technology can be used for wastewater treatment with good results. However, because iron-carbon has high requirements for the pH value of the treatment environment, acid / alkali needs to be added when using iron-carbon packing for wastewater treatment, making the process relatively complex and posing certain safety hazards. Therefore, iron-carbon is currently mostly used in physicochemical reactors for the pretreatment of high-concentration or highly difficult wastewater, and has not been applied to conventional wastewater treatment. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] This disclosure provides a biological contact oxidation method and system for at least partially solving one of the above-mentioned technical problems.

[0006] (II) Technical Solution

[0007] The first aspect of this disclosure provides a biological contact oxidation method, which includes: introducing wastewater into a reaction tank of a biological contact oxidation system, and treating the wastewater based on iron-carbon packing material and activated sludge in the reaction tank; wherein the microorganisms in the iron-carbon packing material and activated sludge undergo a coupled reaction to jointly treat the wastewater.

[0008] According to embodiments of this disclosure, the method further includes: continuously aerating the reaction tank using an aerator during wastewater treatment.

[0009] According to embodiments of this disclosure, during wastewater treatment, microorganisms in activated sludge attach to iron-carbon packing material, producing acidic intermediate metabolites that provide an acidic environment for the iron-carbon packing material. The iron-carbon packing material undergoes micro-electrolysis in the acidic environment, decomposing into iron ions and activated carbon, and the wastewater is treated based on the iron ions and activated carbon.

[0010] The second aspect of this disclosure provides a biological contact oxidation system, which includes: an iron-carbon contact oxidation module and an auxiliary treatment module; wherein the auxiliary treatment module includes activated sludge, and the iron-carbon contact oxidation module treats wastewater through the coupling reaction of iron-carbon packing and microorganisms in the activated sludge; the iron-carbon contact oxidation module includes: at least one iron-carbon packing group; the iron-carbon packing group is composed of a packing mesh and iron-carbon packing, and there is a gap between adjacent iron-carbon packing groups.

[0011] According to an embodiment of this disclosure, the auxiliary treatment module includes: activated sludge, an inlet pipe, and an outlet pipe; wastewater enters the system through the inlet pipe, is treated, and is discharged from the system through the outlet pipe, wherein the settling ratio of the activated sludge is 5% to 15%.

[0012] According to embodiments of this disclosure, the system further includes: an aerator for oxygenation and mixing; the aerators are uniformly arranged among the iron-carbon packing groups.

[0013] According to embodiments of this disclosure, the iron-carbon filler has a specific surface area of ​​1.2 m². 2 / g, physical strength 800 kg / m 2 The bulk density is 1200 g / L, the porosity is ≥ 65%, the iron-carbon ratio is 75% ~ 85%, and the catalyst content is 5%. The filling height of the iron-carbon filler does not exceed 1m, and the iron-carbon filler accounts for 10%~20% of the volume of the reaction system.

[0014] According to embodiments of this disclosure, the height difference between the bottom of the iron-carbon packing group and the bottom of the reaction tank is 40-50 cm.

[0015] According to embodiments of this disclosure, the gas-to-water ratio of the iron-carbon contact oxidation module is 2:1 to 12:1, and the dissolved oxygen concentration is 1 to 2 mg / L.

[0016] According to embodiments of this disclosure, the iron-carbon contact oxidation module has a split structure, and the number of iron-carbon packing groups and the volume of iron-carbon packing in each iron-carbon packing group can be adjusted according to the wastewater quality.

[0017] (III) Beneficial Effects

[0018] The biological contact oxidation method and system disclosed herein have at least the following beneficial effects:

[0019] 1. The biological contact oxidation method and system provided in this disclosure utilizes the acidic intermediate metabolites naturally produced by microorganisms after attaching to iron-carbon packing material. This forms an acidic biofilm on the surface of the iron-carbon packing material, promoting micro-electrolysis and thus degrading organic matter. The reaction does not require the addition of acid or alkali reagents to adjust the pH value, avoiding secondary pollution of wastewater and effluent discoloration. Furthermore, the iron ions from the decomposition of the iron-carbon packing material enhance the settling performance of activated sludge and improve phosphorus removal efficiency. The iron-carbon packing material promotes short-cut nitrification and denitrification by microorganisms, reducing the aeration required in the wastewater treatment process and contributing to energy conservation and emission reduction.

[0020] 2. The biological contact oxidation system provided in this disclosure has good sludge settling properties, and the sludge settling speed is 30% to 50% higher than that of conventional biochemical processes, which can significantly reduce the footprint and save costs.

[0021] 3. The biological contact oxidation system provided in this disclosure has a simple structure, is easy to install, and is flexible in scale. Iron-carbon packing material accounting for less than 20% of the system volume is sufficient to meet process requirements. The packing material is easy to replace and replenish, and can be flexibly adjusted according to actual conditions. Attached Figure Description

[0022] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0023] Figure 1 A schematic diagram of a biological contact oxidation system according to an embodiment of the present disclosure is shown.

[0024] [Attached image labels]

[0025] 1-Inlet pipe; 2-Outlet pipe; 3-Activated sludge; 4-Aerator; 5-Cellulose packing frame; 6-Iron-carbon packing; 7-Cellulose packing frame support beam. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0028] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0029] In the description of this disclosure, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0030] Throughout the accompanying drawings, identical elements are represented by the same or similar reference numerals. Conventional structures or constructions have been omitted where they may cause confusion in understanding this disclosure. Furthermore, the shapes, dimensions, and positional relationships of the components in the drawings do not reflect actual size, scale, or actual positional relationships. Additionally, any reference numerals placed between parentheses in the claims should not be construed as limiting the claims.

[0031] Similarly, to simplify this disclosure and aid in understanding one or more of the various aspects of the disclosure, in the above description of exemplary embodiments of the present disclosure, various features of the present disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. The use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refers to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present disclosure. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] The biological contact oxidation method provided in this embodiment includes: introducing wastewater into the reaction tank of a biological contact oxidation system, and treating the wastewater based on the iron-carbon packing material and activated sludge in the reaction tank; wherein the microorganisms in the iron-carbon packing material and activated sludge undergo a coupling reaction to jointly treat the wastewater.

[0034] Specifically, in the wastewater treatment process, continuous aeration is achieved by using aerators to supply oxygen to the reaction tank. Aeration provides oxygen to the microorganisms in the activated sludge for their respiration and metabolism. Furthermore, the continuous aeration process drives the flow of wastewater and activated sludge, creating a mixing effect that keeps the microorganisms in the activated sludge in suspension, increasing the contact area between the microorganisms and the wastewater, reducing dead zones in the wastewater, and improving treatment efficiency.

[0035] During wastewater treatment, microorganisms in the activated sludge attach to the iron-carbon packing material, producing acidic intermediate metabolites that provide an acidic environment for the packing. In this acidic environment, the iron-carbon packing material undergoes micro-electrolysis, decomposing into iron ions and activated carbon. The wastewater is then treated based on these iron ions and activated carbon.

[0036] Specifically, the microorganisms attached to the iron-carbon packing material will naturally metabolize anaerobic sulfate-reducing bacteria and aerobic iron-oxidizing bacteria, or acidic intermediate metabolites of other anaerobic or facultative bacteria, leading to acidification of the extracellular environment and forming an iron-carbon-microorganism coupling effect, effectively treating recalcitrant organic matter and promoting the biochemical treatment effect of microorganisms.

[0037] During aeration and micro-electrolysis, the iron-carbon packing material releases iron ions and activated carbon into the wastewater. The iron ions help retain soluble proteins and carbohydrates produced during biodegradation within the activated sludge flocs, thus reducing the organic matter concentration in the effluent. This effectively reduces the bulking of filamentous bacteria in the activated sludge, resulting in denser flocs and improved settling performance. It also enhances phosphorus removal from the wastewater. Activated carbon, with its porous structure, abundant surface-active groups, and various mineral salts, adsorbs pollutants from the wastewater, further improving purification efficiency.

[0038] Based on the above-described biological contact oxidation method, this disclosure also provides a biological contact oxidation system. The following will be combined with... Figure 1 The system is described in detail.

[0039] Figure 1 A schematic diagram of a biological contact oxidation system according to an embodiment of the present disclosure is shown.

[0040] like Figure 1 As shown, the biological contact oxidation system provided in this disclosure mainly includes an iron-carbon contact oxidation module, an auxiliary treatment module, and an aerator.

[0041] The iron-carbon contact oxidation module includes at least one set of iron-carbon packing groups, which consists of a packing mesh frame 5 and iron-carbon packing 6, with gaps between adjacent iron-carbon packing groups. The iron-carbon contact oxidation module has a split structure, and the number of iron-carbon packing groups and the volume of the iron-carbon packing in each group can be adjusted according to the wastewater quality.

[0042] The auxiliary treatment module includes an inlet pipe 1, an outlet pipe 2, and activated sludge 3. Specifically, the activated sludge undergoes a coupling reaction with iron and carbon to jointly treat the wastewater.

[0043] Aerators 4 are evenly arranged among the iron-carbon packing groups for oxygenation and mixing. On the one hand, the aerators transfer oxygen from the air into the mixed liquor to meet the respiration needs of microorganisms in the activated sludge. On the other hand, the aerators keep the mixed liquor in a vigorous mixing state, ensuring full contact between activated sludge, dissolved oxygen, and organic matter while preventing sludge deposition.

[0044] The wastewater treatment process of the biological contact oxidation system provided in this embodiment includes: wastewater enters the iron-carbon contact oxidation system through the inlet pipe 1, is aerated by the aerator 4, and the iron-carbon packing 6 and activated sludge 3 work together to degrade organic matter, thereby completing the wastewater treatment, and the treated wastewater is discharged through the outlet pipe 2.

[0045] In some embodiments, there are gaps between adjacent iron-carbon packing groups, which helps to ensure sufficient contact between sewage and packing, improves sewage treatment efficiency, and the gaps between adjacent iron-carbon packing groups can ensure that water can flow smoothly through the packing layer, avoid clogging problems, and guarantee sewage treatment efficiency.

[0046] In some embodiments, the aerator 4 is a liftable tube aerator, which is connected to the main aeration pipe by a flange. When the aerator needs to be replaced, the aerator to be replaced can be rotated out of the packing area and then removed from between the packings for easy maintenance.

[0047] In some embodiments, the surface area of ​​the iron-carbon filler ratio is 1.2 m². 2 / g, physical strength is 800 kg / m 2 The bulk density is 1200 g / L, the porosity is ≥ 65%, the iron-carbon ratio is 75% ~ 85%, and the catalyst content is 5%.

[0048] In some embodiments, the settling ratio of activated sludge 3 to SV30 is 5% to 15%.

[0049] In some embodiments, the filling height of the iron-carbon packing does not exceed 1 m, and the volume of the iron-carbon packing accounts for 10% to 20% of the volume of the reaction system, in order to avoid clogging of the packing and excessive burden on the packing mesh.

[0050] In some embodiments, the iron-carbon packing assembly is mounted on the packing mesh support beam 7, with a height difference of 40-50 cm between the bottom of the iron-carbon packing assembly and the bottom of the reaction tank. Maintaining a certain height difference prevents the iron-carbon packing from directly contacting the bottom of the reaction tank, thus avoiding clogging problems caused by excessively large packing particles or excessive bottom sediment. This helps ensure smooth wastewater flow and continuous wastewater treatment. Furthermore, an appropriate height difference ensures more uniform aeration, avoiding insufficient aeration pressure or uneven aeration due to excessive packing accumulation, thereby improving wastewater treatment efficiency.

[0051] In some embodiments, the air-to-water ratio of the iron-carbon contact oxidation module is 2:1 to 12:1, and the dissolved oxygen concentration is 1 to 2 mg / L. Compared with the traditional contact oxidation method, the iron-carbon packing biofilm used in this embodiment forms a good anaerobic and facultative anaerobic environment, eliminating the need for excessively high dissolved oxygen levels that could disrupt the reaction environment. Furthermore, vigorous aeration can easily cause the biofilm to detach. Simultaneously, the lower dissolved oxygen level promotes the accumulation of nitrite-oxidizing bacteria, facilitating short-cut nitrification and denitrification. Therefore, the entire process requires a lower aeration volume, which is beneficial for energy saving and consumption reduction.

[0052] In traditional wastewater treatment processes, iron-carbon packing materials are highly correlated with the pH value of the environment. Therefore, it is necessary to adjust the pH value of the treatment environment by adding acid and / or alkali to complete the wastewater treatment.

[0053] This embodiment uses iron-carbon as a packing material, which works in conjunction with microorganisms in activated sludge to treat wastewater, thereby effectively improving wastewater treatment efficiency. After the microorganisms attach to the iron-carbon packing material, they produce acidic intermediate metabolites, forming an acidic biofilm on the surface of the packing material. This provides an acidic environment for wastewater treatment, promoting micro-electrolysis and thus degrading organic matter. In this process, there is no need to add acid or alkali reagents to adjust the pH value, avoiding secondary pollution and effluent discoloration problems caused by these reagents. This simplifies the wastewater purification process while improving the purification effect.

[0054] Compared to traditional iron-carbon treatment, this disclosure provides an acidic environment for the iron-carbon packing material by setting activated sludge in the biological contact oxidation system. This avoids the need for adjustment with industrial acids and alkalis in traditional processes, effectively simplifying the steps of treating wastewater with iron-carbon packing material and improving wastewater treatment efficiency and safety.

[0055] Furthermore, the biological contact oxidation system provided in this disclosure has a simple structure, is easy to install, and its scale is flexible and adjustable. Compared to the biological filter process, the reaction system of this disclosure does not require backwashing, and the iron-carbon packing material only needs to account for less than 20% of the volume in the system to meet the process requirements. The packing material is easy to replace and replenish, and can be flexibly adjusted according to the project situation.

[0056] To verify that the wastewater treatment capacity of the disclosed system is superior to that of the traditional packing-type wastewater biochemical reaction system, the same batch of wastewater was treated using both the disclosed system and the traditional packing-type wastewater biochemical reaction system. Wastewater was introduced into both systems in batches, and after remaining in each system for 6 hours, it was discharged from both systems. Multiple batches of experiments were repeated to test the treatment stability of the two systems and to compare the effluent pollutant concentration and sedimentation efficiency under the two systems.

[0057] It should be noted that, apart from the material of the packing material used, the systems disclosed herein and traditional packing wastewater biochemical reaction systems have the same structure. The packing particle size is 5-8 mm, and the filling volume ratio of the two packing materials is 20%.

[0058] Table 1. Pollutant concentrations of the same batch of wastewater after treatment by two different systems.

[0059]

[0060] Table 2. Average settling velocity of activated sludge under the two systems

[0061]

[0062] As shown in Tables 1 and 2, the biological contact oxidation system of this disclosure consistently outperforms the traditional packing-type wastewater biochemical reaction system. This disclosure provides higher treatment efficiency, shorter sludge settling time, and saves on floor space and energy consumption.

[0063] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of this disclosure, those skilled in the art can make various substitutions and modifications, all of which should be included within the protection scope of this disclosure.

Claims

1. A biological contact oxidation method, characterized in that, The method includes: Wastewater is introduced into the reaction tank of a biological contact oxidation system, where it is treated based on the iron-carbon packing material and activated sludge in the reaction tank. In this process, the iron-carbon packing material and the microorganisms in the activated sludge undergo a coupled reaction to jointly treat the wastewater. The iron-carbon packing material is filled in an iron-carbon packing assembly, which consists of a packing mesh and iron-carbon packing material, with gaps between adjacent iron-carbon packing assemblies. The height difference between the bottom of the iron-carbon packing assembly and the bottom of the reaction tank is 40-50 cm. During the wastewater treatment process, the microorganisms in the activated sludge attach to the iron-carbon packing material, producing acidic intermediate metabolites, providing an acidic environment for the iron-carbon packing material. The iron-carbon packing material undergoes micro-electrolysis in the acidic environment, treating the wastewater through a series of electrochemical effects and flocculation reactions. The acidic intermediate metabolites include at least one of the following: anaerobic sulfate-reducing bacteria, aerobic iron-oxidizing bacteria, and facultative bacteria metabolized by microorganisms. The acidic intermediate metabolites are used to cause acidification of the extracellular environment and form an iron-carbon-microorganism coupling reaction. In the wastewater treatment process, aerators evenly arranged between iron-carbon packing groups provide continuous aeration, and the treated wastewater is discharged through the effluent pipe. The aerators are used to provide oxygen to the microorganisms in the activated sludge for their respiratory metabolism, and to drive the flow of wastewater and activated sludge, so that the microorganisms in the activated sludge remain in suspension, increasing the contact area between the microorganisms and the wastewater and reducing dead zones in the wastewater.

2. A biological contact oxidation system for performing the biological contact oxidation method according to claim 1, characterized in that, The system includes: Iron-carbon contact oxidation module and auxiliary processing module; The auxiliary treatment module includes activated sludge, and the iron-carbon contact oxidation module treats wastewater by coupling the iron-carbon packing material and the microorganisms in the activated sludge. The iron-carbon contact oxidation module includes: at least one iron-carbon packing group; the iron-carbon packing group is composed of a packing mesh frame and iron-carbon packing, and there is a gap between adjacent iron-carbon packing groups; the height difference between the bottom of the iron-carbon packing group and the bottom of the reaction tank is 40~50 cm. During the wastewater treatment process, the microorganisms in the activated sludge attach to the iron-carbon packing material, producing acidic intermediate metabolites, which provide an acidic environment for the iron-carbon packing material. The iron-carbon packing material undergoes micro-electrolysis in the acidic environment, decomposing into iron ions and activated carbon, and the wastewater is treated based on the iron ions and activated carbon. The acidic intermediate metabolites include at least one of the following: anaerobic sulfate-reducing bacteria, aerobic iron-oxidizing bacteria, and facultative bacteria, which lead to acidification of the extracellular environment and the formation of iron-carbon-microorganism coupling reactions. The system further includes: aerators for oxygenation and mixing; the aerators are evenly arranged between the iron-carbon packing groups; during the wastewater treatment process, continuous aeration is achieved based on the aerators, and the treated wastewater is discharged through the effluent pipe; the aerators are used to provide oxygen to the microorganisms in the activated sludge for their respiratory metabolism, and to drive the flow of wastewater and activated sludge, keeping the microorganisms in the activated sludge in a suspended state, increasing the contact area between the microorganisms and the wastewater, and reducing dead zones in the wastewater.

3. The biological contact oxidation system according to claim 2, characterized in that, The auxiliary treatment module includes: activated sludge, inlet pipe, and outlet pipe; The wastewater to be treated enters the system through the inlet pipe, and after treatment, it is discharged from the system through the outlet pipe. The settling ratio of the activated sludge is 5% to 15%.

4. The biological contact oxidation system according to claim 2, characterized in that, The iron-carbon filler has a specific surface area of ​​1.2 m² / g, a physical strength of 800 kg / m², a bulk density of 1200 g / L, a porosity of ≥65%, an iron-carbon ratio of 75% to 85%, and a catalyst content of 5%. The filling height of the iron-carbon filler does not exceed 1 m, and the iron-carbon filler occupies 10% to 20% of the volume of the reaction system.

5. The biological contact oxidation system according to claim 2, characterized in that, The gas-to-water ratio of the iron-carbon contact oxidation module is 2:1 to 12:1, and the dissolved oxygen concentration is 1 to 2 mg / L.

6. The biological contact oxidation system according to claim 2, characterized in that, The iron-carbon contact oxidation module has a split structure, and the number of iron-carbon packing groups and the volume of iron-carbon packing in each group are adjusted according to the wastewater quality.

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