A sewage treatment system

Abstract

The utility model discloses a sewage treatment system, including the primary aerobic tank, primary sedimentation tank, anoxic tank, secondary aerobic tank and secondary sedimentation tank of sequential intercommunication, be provided with the lift pump in primary sedimentation tank and communicate with primary aerobic tank through sludge backflow pipe, and the supernatant of primary sedimentation tank is introduced to in anoxic tank, and be provided with nitration liquid backflow pump in secondary aerobic tank and introduce to in anoxic tank through nitration liquid backflow pipe, and the backflow pump is established in secondary sedimentation tank and introduce to in anoxic tank through secondary backflow pipe with sludge;Primary aerobic tank and secondary aerobic tank are provided with aeration device. The utility model discloses a sewage treatment system, and wastewater is introduced to in primary aerobic tank, utilizes the aeration device in primary aerobic tank, and the biodegradable toxic substance is oxidized degradation, and the non-biodegradable toxic substance is adsorbed with active sludge, and is discharged with the sludge discharge system, and the biochemical toxicity of the next process unit is reduced. When the water inlet toxicity material is higher, adopts high backflow ratio, and the water inlet toxicity material is reduced to below half inhibition concentration, and the degradation efficiency can be effectively improved.

Description

Technical Field

[0001] This utility model relates to the field of water treatment technology, and more specifically, to a wastewater treatment system. Background Technology

[0002] During the operation of a wastewater treatment plant, the activated sludge microorganisms in the biological treatment process can be affected by toxic and harmful substances in the incoming wastewater, causing a decrease in microbial activity or death, which can prevent the biological treatment system from operating normally or even lead to the paralysis of the biological treatment system.

[0003] Currently, there are many methods for the biological removal of toxic substances from wastewater, such as: advanced oxidation, which oxidizes toxic substances through physical means, with the end products being non-toxic or low-toxic substances; cultivating specific bacterial strains, which treats toxic wastewater by screening for strains that can degrade characteristic pollutants; process control, which utilizes extracellular enzymes to degrade toxic substances by optimizing hydrolysis process parameters; and activated carbon adsorption, which adsorbs some toxic substances in wastewater by adding activated carbon.

[0004] However, while advanced oxidation can treat most toxic substances, the end products are non-toxic or low-toxic substances, resulting in high investment and operating costs for low-toxic wastewater. Furthermore, specific bacterial strains exhibit specificity in degrading pollutants in water, requiring re-screening of strains when pollutants change, and the screening cycle is lengthy. Secondly, in hydrolysis processes, anaerobic digestion can degrade most toxic substances through extracellular enzymes, but certain organic compounds can inhibit anaerobic digestion. Activated carbon adsorption, on the other hand, has high operating costs, and its lack of selectivity for toxicity leads to large dosages. The treated activated carbon must then be treated as hazardous waste, further increasing operating costs.

[0005] Therefore, it is necessary to propose a wastewater treatment system to solve the above problems, which is of great significance for reducing the energy consumption of biological treatment process systems and improving their operating efficiency. Utility Model Content

[0006] This invention provides a wastewater treatment system to address the problem that the high toxicity of digestive microorganisms in existing wastewater treatment processes reduces the effectiveness and cost of wastewater treatment.

[0007] According to one aspect of the present invention, a wastewater treatment system is provided, comprising a primary aerobic tank, a primary sedimentation tank, an anoxic tank, a secondary aerobic tank, and a secondary sedimentation tank connected in sequence. A lift pump is installed in the primary sedimentation tank and connected to the primary aerobic tank via a sludge return pipe. The supernatant from the primary sedimentation tank is introduced into the anoxic tank. A nitrification liquid return pump is installed in the secondary aerobic tank and introduces nitrification liquid into the anoxic tank via a nitrification liquid return pipe. A return pump in the secondary sedimentation tank introduces sludge into the anoxic tank via a secondary return pipe. Aeration devices are installed in both the primary and secondary aerobic tanks.

[0008] Based on the above scheme, preferably, the aeration device includes a main pipe and aeration heads set at the bottom of the pool. The aeration heads are multiple and spaced apart along the length of the main pipe. The aeration heads are located at the bottom of the primary aerobic pool and the secondary aerobic pool.

[0009] Based on the above scheme, preferably, the aeration head includes a guide head, a guide cylinder, and a diffuser. The guide head is installed on the main pipe, the guide cylinder has a core head installed in the middle, and a spiral guide plate is installed between the core head and the guide cylinder. The diffuser is installed at the bottom of the guide cylinder by bolts, and the top of the guide head is connected to the core head.

[0010] Preferably, based on the above scheme, the guide head has a stepped guide hole in the middle, and a flow guide hole that penetrates the guide hole is provided at the upper part of the guide head. An adjusting ball is installed in the guide hole, and the adjusting ball is movably disposed in the guide hole to adjust the opening and closing of the flow guide hole.

[0011] Based on the above scheme, preferably, the diffuser has a skirt at the bottom and is spaced apart from the main pipe, the inner edge of the diffuser has a mounting edge, and the mounting edge has mounting holes adapted to the bolts.

[0012] Preferably, based on the above scheme, there are multiple guide cylinders, and the top of the guide cylinder is provided with a countersunk groove, and the bottom of the guide cylinder is provided with a protrusion adapted to the countersunk groove, and the bolt passes through the protrusion and the countersunk groove.

[0013] Based on the above scheme, preferably, the guide plate includes at least two plates, the plates are arranged in a spiral shape with the core head as the axis, and the plates are uniformly provided with fine holes.

[0014] Based on the above scheme, a preferred embodiment is that the inner edge of the guide cylinder is provided with a plurality of plug-in posts at intervals, and the plug-in posts are provided with plug-in holes that are compatible with the bolts.

[0015] Based on the above scheme, a preferred embodiment is that the anoxic tank is equipped with a stirring shaft.

[0016] This invention discloses a wastewater treatment system that introduces wastewater into a primary aerobic tank. The aeration device in the primary aerobic tank aerobically degrades biodegradable toxic substances, while non-biodegradable toxic substances are adsorbed by activated sludge and discharged from the system with the sludge, reducing the biochemical toxicity entering the next process unit. When the influent toxicity level is high, a high reflux ratio is used to reduce the influent toxicity to below the half-inhibitory concentration, effectively improving the degradation efficiency.

[0017] On the other hand, this invention improves the aeration device by introducing external air. Most of the external air drawn in through the guide head floats upwards due to buoyancy, and is refined as it passes through the holes in the guide plate, guiding it to form a spiral water flow, i.e., a vortex. During this process, bubbles passing through multiple holes collide and mix with the spiraling wastewater, inhibiting bubble re-coagulation and effectively maintaining the micro-fine state of the bubbles required to supply sufficient dissolved oxygen. Furthermore, the velocity of the spiral water flow caused by the guide plate gradually increases under the buoyancy of the microbubbles in the wastewater, thus creating sufficient stirring force at the top of the air diffuser in the final process. This contributes to the duration of the stirring action and can minimize or suppress problems such as clogging found in traditional membrane diffusers. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments 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. In the drawings:

[0019] Figure 1 This is a schematic diagram of the principle structure of the wastewater treatment system of this utility model;

[0020] Figure 2 This is a bottom view of the aeration head of this utility model;

[0021] Figure 3 This is a top view of the aeration head of this utility model;

[0022] Figure 4 This is an exploded view of the aeration head of this utility model;

[0023] Figure 5 This is a cross-sectional view of the aeration head of this utility model;

[0024] Explanation of icon numbers:

[0025] 1. Primary aerobic tank; 2. Primary sedimentation tank; 3. Anoxic tank; 4. Secondary aerobic tank; 5. Secondary sedimentation tank; 6. Sludge return pipe; 7. Nitrification - 8. Secondary reflux pipe;

[0026] 90. Aeration device; 91. Main pipe; 92. Aeration head; 93. Guide head; 94. Flow guide hole; 95. Adjusting ball; 96. Guide tube; 97. Core head; 98. Countersunk groove; 99. Protrusion; 100. Flow guide plate; 101. Refining hole; 102. Diffuser; 103. Skirt; 104. Mounting edge; 105. Mounting hole; 106. Bolt; 931. Guide hole. Detailed Implementation

[0027] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0028] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of a descriptive feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or sets.

[0029] To keep the drawings concise, only the parts relevant to this invention are shown schematically in each figure, and they do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, only one of the components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0030] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0031] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of the various components of this invention are relative rather than absolute. These descriptions are appropriate when these components are in the positions shown in the drawings. If the descriptions of the positions of these components change, these directional indications also change accordingly.

[0032] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the specific implementation methods of this utility model will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0034] Please see Figure 1 and combined Figure 2 and Figure 3As shown, a wastewater treatment system of this utility model includes a primary aerobic tank 1, a primary sedimentation tank 2, an anoxic tank 3, a secondary aerobic tank 4, and a secondary sedimentation tank 5 connected in sequence. A lift pump is installed in the primary sedimentation tank 2 and connected to the primary aerobic tank 1 through a sludge return pipe 6. The supernatant of the primary sedimentation tank 2 is introduced into the anoxic tank 3. A nitrification liquid return pump is installed in the secondary aerobic tank 4 and introduces it into the anoxic tank 3 through a nitrification liquid return pipe 7. A return pump is installed in the secondary sedimentation tank 5 and introduces sludge into the anoxic tank 3 through a secondary return pipe 8. An aeration device 90 is installed in the primary aerobic tank 1 and the secondary aerobic tank 4.

[0035] Wastewater enters from the bottom of the primary aerobic tank 1 and flows into the primary sedimentation tank 2 from the top. In the primary sedimentation tank 2, sludge and water are separated, and the supernatant enters the anoxic tank 3. Sludge is returned to the primary aerobic tank 1 to maintain its concentration. The supernatant from the primary sedimentation tank 2 enters from the bottom of the anoxic tank 3, and the mixed liquor flows out from the top of the anoxic tank 3. Wastewater then enters from the bottom of the secondary aerobic tank 4 and flows out from the top of the secondary aerobic tank 5 for further sludge and water separation. The anoxic tank 3 is equipped with a mixing system to ensure thorough mixing of sludge and water, while the secondary aerobic tank 4 is equipped with an aeration system to oxygenate the tank.

[0036] This invention employs a pre-treatment aerobic tank. Wastewater enters the bottom of the primary aerobic tank 1, where it is aerated and oxygenated, ensuring complete mixing of the wastewater and activated sludge. Toxic substances are aerobically degraded in the primary aerobic tank 1. The dissolved oxygen in the primary aerobic tank 1 is controlled at 2–4 mg / L, pH 6–9, and conductivity <20 mS / cm.

[0037] The sludge from the primary aerobic tank 1 is returned to the primary aerobic tank 1, and the sludge from the secondary aerobic tank 4 is returned to the anoxic tank 3 and the secondary aerobic tank 4, with a return ratio of 0.8-1.5. This is to prevent the nitrifying bacteria from dying due to the return of sludge from the anoxic tank 3 and the secondary aerobic tank 4 to the primary aerobic tank 1.

[0038] This invention utilizes separate sludge recirculation to achieve enrichment and cultivation of different bacterial species, thereby increasing the abundance of nitrifying bacteria.

[0039] In the secondary aerobic tank 4, aeration is carried out, with dissolved oxygen at 2-4 mg / L, pH greater than 6.5, and conductivity less than 20 mS / cm. Alkali is added if necessary. In the anoxic tank 3, an anoxic agitator is installed with a stirring power of 8 W / m³, controlling the carbon-to-nitrogen ratio at 4:1, pH less than 8.5, and acid is added if necessary.

[0040] The nitrification liquor reflux in nitrification liquor reflux pipe 7 needs to be controlled at 400% to 800% (high reflux ensures sufficient dilution of the influent with the effluent, reducing the toxicity of the influent).

[0041] This invention enables most toxic substances to be degraded to varying degrees by aerobic microorganisms. At the biochemical front end, aerobic aeration degrades biodegradable toxic substances in wastewater, while non-biodegradable toxic substances are adsorbed by activated sludge and discharged from the system with the sludge. This reduces the biochemical toxicity entering the next process unit. When the influent toxicity is high, a high reflux ratio is used to reduce the influent toxicity to below the half-inhibition concentration, effectively improving degradation efficiency. For example, when the methanol concentration in wastewater reaches 800 mg / L, nitrifying bacteria are inhibited, while heterotrophic bacteria can degrade methanol at a rate of 120 mg / gvss·h. 800 mg / L methanol can be reduced to below 10 mg / L aerobically in 3 hours. Similar reductions are observed for dichloromethane, trichloromethane, phenol, o-cresol, m-cresol, p-cresol, toluene, formaldehyde, carbon disulfide, etc.

[0042] Meanwhile, in this patent, nitrifying bacteria circulate in the nitrification liquid return pipe 7, and sludge does not enter the O tank at the very beginning, avoiding direct contact between nitrifying bacteria and wastewater with high concentrations of toxic substances. Simultaneously, the concentration of toxic substances in the wastewater is reduced to below the inhibitory concentration for nitrifying bacteria in the aerobic tank.

[0043] It is worth noting that, in order to improve the aeration effect of the aeration device 90 in the primary aerobic tank 1 and the secondary aerobic tank 4, the aeration device 90 of this utility model includes a main pipe 91 and an aeration head 92 set at the bottom of the tank. The aeration head 92 is a plurality of aeration heads set at intervals along the length of the main pipe 91, and the aeration head 92 is located at the bottom of the primary aerobic tank 1 and the secondary aerobic tank 4.

[0044] like Figure 3 , Figure 4 and Figure 5 As shown, specifically, the aeration head 92 includes a guide head 93, a guide cylinder 96, and a diffuser 102. The guide head 93 is mounted on the main pipe 91. A core head 97 is mounted in the middle of the guide cylinder 96, and a spiral guide plate 100 is mounted between the core head 97 and the guide cylinder 96. The diffuser 102 is mounted on the bottom of the guide cylinder 96 by bolts 106. The top of the guide head 93 is connected to the core head 97. A stepped guide hole 931 is provided in the middle of the guide head 93, and a guide hole 94 penetrating the guide hole 931 is provided in the upper part of the guide head 93. The guide hole 931 has a stepped structure that is larger at the top and smaller at the bottom. An adjusting ball 95 is installed in the upper guide hole 931. The adjusting ball 95 is movably disposed in the guide hole 931 to adjust the opening and closing of the guide hole 94.

[0045] After the main pipe 91 introduces external gas, it acts on the regulating ball 95 in the guide hole 931 through the guide head 93. The regulating ball 95 floats upward due to the strong buoyancy, so that the guide hole 94 and the guide hole 931 are connected. After the gas is introduced from the guide hole 94, it acts on the spiral guide plate 100. The guide plate 100 forms a vortex structure. Multiple fine holes 101 are provided on the guide plate 100. The airflow is further refined and separated by the fine holes 101.

[0046] During this process, bubbles passing through multiple fine holes 101 collide and mix with the spiraling wastewater. This inhibits bubble re-coagulation, effectively maintaining the micro-fine state of the bubbles required to supply sufficient dissolved oxygen. Furthermore, the velocity of the spiral wastewater flow caused by the guide plate 100 gradually increases under the buoyancy of the microbubbles contained in the wastewater, thereby creating sufficient agitation at the top of the aeration device 90 in the final process.

[0047] In this case, the wastewater or sludge contained therein is also designed to pass through the guide tube of the air diffuser 102. Therefore, the vortex wastewater flow itself acts on the wastewater and sludge in the primary aerobic tank 1 and the secondary aerobic tank 4. Due to the time that helps the stirring action, problems such as clogging in the conventional membrane diffuser 102 can be minimized or suppressed.

[0048] Specifically, the diffuser 102 of this utility model has a skirt 103 at the bottom, which is spaced apart from the main pipe 91 to facilitate the introduction of sewage at the bottom and mixing with the gas discharged from the guide hole 94. The inner edge of the diffuser 102 is provided with a mounting edge 104, which is provided with mounting holes 105 adapted to bolts 106. There are multiple guide cylinders 96, and the top of the guide cylinder 96 is provided with a countersunk groove 98. The bottom of the guide cylinder 96 is provided with a protrusion 99 adapted to the countersunk groove 98. The bolts 106 pass through the protrusion 99 and the countersunk groove 98. The guide plate 100 includes at least two plates, which are spirally arranged with the core head 97 as the axis. The plates are uniformly provided with fine holes 101.

[0049] Furthermore, the inner edge surface of the guide cylinder 96 of this utility model is provided with a plurality of plug-in posts at intervals, and the plug-in posts are provided with plug-in holes that are compatible with the bolts 106.

[0050] Furthermore, this invention also includes a stirring shaft installed inside the anoxic tank 3.

[0051] This invention discloses a wastewater treatment system that introduces wastewater into a primary aerobic tank 1. The aeration device 90 within the primary aerobic tank 1 aerobically degrades biodegradable toxic substances, while non-biodegradable toxic substances are adsorbed by activated sludge and discharged from the system along with the sludge, reducing the biochemical toxicity entering the next process unit. When the influent toxicity level is high, a high reflux ratio is employed to reduce the influent toxicity to below the half-inhibitory concentration, effectively improving degradation efficiency.

[0052] Finally, the method described in this application is merely a preferred embodiment and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A wastewater treatment system, characterized in that, The system comprises a primary aerobic tank, a primary sedimentation tank, an anoxic tank, a secondary aerobic tank, and a secondary sedimentation tank, all connected in sequence. A lift pump is installed in the primary sedimentation tank and connected to the primary aerobic tank via a sludge return pipe. The supernatant from the primary sedimentation tank is introduced into the anoxic tank. A nitrification liquid return pump is installed in the secondary aerobic tank and introduces nitrification liquid into the anoxic tank via a nitrification liquid return pipe. A return pump in the secondary sedimentation tank introduces sludge into the anoxic tank via a secondary return pipe. Aeration devices are installed in both the primary and secondary aerobic tanks.

2. The wastewater treatment system as described in claim 1, characterized in that, The aeration device includes a main pipe and aeration heads installed at the bottom of the pool. Multiple aeration heads are spaced apart along the length of the main pipe and are located at the bottom of the primary aerobic pool and the secondary aerobic pool.

3. A wastewater treatment system as described in claim 2, characterized in that, The aeration head includes a guide head, a guide cylinder, and a diffuser. The guide head is mounted on the main pipe. A core head is mounted in the middle of the guide cylinder, and a spiral guide plate is mounted between the core head and the guide cylinder. The diffuser is bolted to the bottom of the guide cylinder, and the top of the guide head is connected to the core head.

4. A wastewater treatment system as described in claim 3, characterized in that, The guide head has a stepped guide hole in the middle, and a flow guide hole that penetrates the guide hole is provided at the upper part of the guide head. An adjusting ball is installed in the guide hole, and the adjusting ball is movably disposed in the guide hole to adjust the opening and closing of the flow guide hole.

5. A wastewater treatment system as described in claim 3, characterized in that, The diffuser has a skirt at its bottom, which is spaced apart from the main pipe. The inner edge of the diffuser has a mounting edge, and the mounting edge has mounting holes that are compatible with the bolts.

6. A wastewater treatment system as described in claim 5, characterized in that, The guide cylinders are multiple, and the top of the guide cylinder is provided with a countersunk groove, and the bottom of the guide cylinder is provided with a protrusion adapted to the countersunk groove. The bolt passes through the protrusion and the countersunk groove.

7. A wastewater treatment system as described in claim 4, characterized in that, The guide plate includes at least two plates, which are spirally arranged around the core head, and the plates are uniformly provided with fine holes.

8. A wastewater treatment system as described in claim 7, characterized in that, The inner edge of the guide tube is provided with a plurality of plug-in posts spaced apart, and each plug-in post is provided with a plug-in hole that is compatible with the bolt.

9. A wastewater treatment system as described in claim 1, characterized in that, The anoxic tank is equipped with a stirring shaft.

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