A low-carbon emission sewage treatment system and method based on three-color sludge

Abstract

The present invention discloses a low-carbon emission sewage treatment system and method based on three-color sludge. The system includes a countercurrent adsorption tower (column), an anaerobic methane production reactor, an anaerobic ammonium oxidation reaction unit, an aerobic recovery reactor, etc. The method is a separation method for urban domestic sewage. It first uses gray activated sludge to intercept raw water suspended matter and ammonia, then uses black anaerobic sludge to remove organic matter and produce methane (COD), then uses red anaerobic ammonium oxidation sludge to remove ammonia nitrogen, and finally uses a reagent (Fe 3+ ) removes phosphorus, purifying wastewater. The activated sludge is then reactivated and recycled for reuse. Compared to traditional processes, this method consumes less energy and produces less greenhouse gases, or the greenhouse gases are recovered, making it a low-carbon process.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a low-carbon emission sewage treatment system and method based on three-color sludge. Background Art

[0002] Traditional wastewater treatment processes require extensive aeration to convert organic matter in wastewater into CO2 and H2O, consuming significant amounts of energy and producing significant greenhouse gases. If anaerobic wastewater treatment could be employed and the resulting CH4 recovered, direct carbon emissions from the process would be significantly reduced.

[0003] However, the influent COD concentration of municipal wastewater treatment plants is generally too low, typically only 200-250 mg / L, and in some areas even below 100 mg / L. Direct anaerobic treatment consumes enormous energy and has a very low CH4 recovery rate, making it unprofitable. Therefore, anaerobic treatment has historically been used only in sludge digestion areas in municipal wastewater treatment plants. However, because existing wastewater treatment plants mostly use long sludge age processes, anaerobic digestion is economically uneconomical and is therefore not widely used. Summary of the Invention

[0004] To address these issues, the present invention provides a low-carbon wastewater treatment system and method based on tri-color sludge, based on the characteristics of raw domestic sewage, which primarily contains feces and low levels of dissolved organic matter. This method targets domestic sewage that has not been treated in septic tanks. Raw sewage has a high COD concentration (generally exceeding 500 mg / L), and the organic matter in the raw water is primarily particulate, with low levels of dissolved organic matter.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] A low-carbon emission sewage treatment method based on three-color sludge, comprising the following steps:

[0007] S1. The gradually settling activated sludge and adsorbent mixture is brought into countercurrent contact with the gradually rising sewage, so that the pollutants in the sewage are adsorbed and retained and form a sludge mixture with the activated sludge and then settle together;

[0008] S2. using anaerobic sludge to perform anaerobic biochemical treatment on the sludge mixture to remove organic matter, generate methane and recover it;

[0009] S3, performing anaerobic ammonium oxidation treatment on the effluent mixture (including sewage sludge) formed after the treatment in step S2 using anaerobic ammonium oxidation sludge, so as to convert ammonia nitrogen in the mixture into nitrogen gas, thereby achieving denitrification;

[0010] S4. performing aerobic recovery treatment on the effluent mixture (including sewage sludge) formed after the treatment in step S3 to restore the activity of the activated sludge in the mixture and remove residual organic matter;

[0011] S5, the impurities in the mixture treated in step S4 are discharged as excess sludge, and the activated sludge that has recovered its activity is returned to step S1 to participate in the cycle;

[0012] S6. Based on the cycle of S1-S5, the wastewater treated in step S1 is discharged after chemical dephosphorization and disinfection.

[0013] A further improvement is that the sewage is domestic sewage that has not been treated in a septic tank, the COD concentration in the sewage reaches 500-600 mg / L, and the COD is mainly undissolved particulate matter.

[0014] A further improvement is that the activated sludge in step S1 is in the form of gray flocs, the anaerobic sludge in step S2 is in the form of black granules, and the anaerobic ammonium oxidation sludge in step S3 is in the form of red granules, so it is called three-color sludge.

[0015] A further improvement is that step S1 is carried out using a countercurrent adsorption tower (column), with the raw sewage water entering from the lower part of the tower body and the water being discharged from the upper part of the tower body, the reflowing activated sludge entering from the upper part of the tower body, and the settled sludge mixture being discharged from the lower part of the tower body, and the relationship between the flow rates is: the upper reflowing activated sludge flow rate is equal to the discharge flow rate of the lower mixture, and the lower sewage raw water entering flow rate is equal to the upper water outlet flow rate.

[0016] A further improvement is that the SS concentration in the countercurrent adsorption tower (column) is 6000-12000 mg / L, the net height of the effective sedimentation area is not less than 3m, and the sludge sedimentation time is 0.5~1.5h.

[0017] A further improvement is that the specific process of step S3 is: the effluent mixture formed after the treatment in step S2 is equally discharged in two parts, 50% of the effluent mixture is subjected to aerobic nitritation treatment to convert ammonia nitrogen in the effluent mixture into nitrite, and then the remaining 50% of the effluent mixture and the effluent mixture after the aerobic nitritation treatment are subjected to anaerobic ammonia oxidation treatment using anaerobic ammonia oxidation sludge to convert ammonia nitrogen in the effluent mixture into nitrogen gas.

[0018] A further improvement is that slight stirring is performed during the anaerobic biochemical treatment process of step S2 and the anaerobic ammonium oxidation treatment process of step S3 to prevent the activated sludge in the mixture from being entrapped by the anaerobic sludge and the anaerobic ammonium oxidation sludge, aeration is performed during the aerobic nitritation treatment process of step S3 and the aerobic recovery treatment process of step S4, and stirring is performed during the aerobic recovery treatment process of step S4 to form an annular flow field.

[0019] A further improvement is that during the aerobic nitritation treatment in step S3 and the aerobic recovery treatment in step S4, the hydraulic retention time HRT is 1-2 hours.

[0020] The present invention also provides a system for implementing the above-mentioned low-carbon emission sewage treatment method based on three-color sludge, the system comprising:

[0021] Countercurrent adsorption tower (column) is used to use the gradually settling activated sludge and adsorbent mixture to contact the gradually rising sewage in the reverse direction, so that the pollutants in the sewage are adsorbed and retained and form a sludge mixture with the activated sludge and then settle together;

[0022] Anaerobic reactor, which uses anaerobic sludge to carry out anaerobic biochemical treatment on the sludge mixture containing organic matter to remove the organic matter, produce methane and recover it;

[0023] The anaerobic ammonium oxidation reaction unit uses anaerobic ammonium oxidation sludge to treat the effluent mixture, so as to convert the ammonia nitrogen in the sewage into nitrogen gas and achieve denitrification;

[0024] Aerobic recovery reactor, which performs aerobic recovery treatment on the effluent mixture to restore the activity and adsorption performance of the activated sludge and further remove residual organic matter;

[0025] The countercurrent adsorption tower (column), anaerobic reactor, anaerobic ammonium oxidation reaction unit and aerobic recovery reactor are sequentially connected through a mixture pipe, and an activated sludge return pipe is provided between the aerobic recovery reactor and the countercurrent adsorption tower (column).

[0026] A further improvement is that the anaerobic ammonium oxidation reaction unit includes:

[0027] an aerobic nitritation reactor, used for performing aerobic nitritation treatment on the mixture to convert ammonia nitrogen in the mixture into nitrite;

[0028] The anaerobic ammonium oxidation reactor is used to perform anaerobic ammonium oxidation treatment on the mixture using anaerobic ammonium oxidation sludge, so as to convert ammonia nitrogen in the mixture into nitrogen gas.

[0029] The technical principle of this invention is that when the COD concentration of raw sewage is high and there are many particulate organic matter, the principle that particulate matter is easily intercepted by the suspended sludge layer (similar to the crowding sedimentation principle of traditional sedimentation) is used to concentrate the COD concentration of raw water by more than 5 to 10 times. The sewage flow entering the anaerobic stage is equivalent to 1 / (5 to 10) of the raw water. At this time, the use of anaerobic biological treatment has economic and technical advantages. The surface of activated sludge is negatively charged, and it is resistant to dissolved ammonia in the influent (mainly NH4 in a medium pH environment). +The anaerobic bioreactor (ANAMMOX) process (which exists in a variety of forms) possesses a certain degree of adsorption capacity. When the sludge concentration is high, the total adsorption capacity is sufficient to carry ammonia into the subsequent reactor. Surfactants in wastewater (derived from detergents) are generally present in an undissolved state and can also be intercepted and entered into the anaerobic bioreactor. The primary pollutant remaining in the raw water after anaerobic metabolism is ammonia nitrogen, and its concentration is concentrated 5-10 times compared to the raw water. The ANAMMOX method also offers significant technical advantages for denitrification. After two anaerobic treatments, the coagulation properties of the original activated sludge decrease significantly. Aeration then restores its activity and further reduces the residual organic matter in the wastewater.

[0030] The beneficial effects of the present invention are: in the three-color sludge process system, after the gray sludge filters and adsorbs the raw sewage, the particulate pollutants in the raw water are intercepted and the ammonia is adsorbed, so the COD and ammonia nitrogen concentrations can be increased several times, and then anaerobic biological treatment is carried out to recover methane; after anaerobic black sludge treatment, the COD concentration of the raw water is greatly reduced, and then red sludge is used for anaerobic ammonia oxidation, and the sewage after ammonia removal is subjected to aerobic metabolism, and the sewage is purified. Compared with traditional process methods, this method has low energy consumption, produces less greenhouse gases or the greenhouse gases are recovered (CH4 is recovered, CO2 and N2O are produced in small amounts), and is a low-carbon emission process. Theoretically, if the influent COD concentration is 500 mg / L, the yield of organic matter converted to methane is 90%, and the methane recovery rate is 95%, then 0.299 m3 of methane can be recovered per cubic meter of sewage. 3 Methane, the process does not need to emit methane directly (but part of the methane dissolved in the sewage will be emitted into the atmosphere in the subsequent aerobic process). When the traditional process denitrifies, a large amount of N2O will be produced in the absence of sufficient carbon source in the anoxic tank. This process method does not have an anoxic tank, so theoretically, the amount of N2O produced is relatively small. In the traditional process method, most of the organic matter (COD) in the influent is eventually converted into CO2, and the direct carbon emission is very significant. In this technical method, the organic matter is basically converted into CH4, and the amount of CO2 produced will be significantly reduced. Therefore, compared with the traditional process, this method has significantly reduced carbon emissions, a high energy recovery rate, and a simple and feasible process. However, the premise of the technical solution of the present invention is that septic tanks are no longer set up for domestic drainage, and the sewage is not treated in septic tanks, so there is little COD loss, and the COD composition is mainly particulate organic matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a system principle diagram of the present invention. DETAILED DESCRIPTION

[0032] The present application is described in further detail below in conjunction with the accompanying drawings. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0033] like Figure 1 As shown, a low-carbon emission sewage treatment method based on three-color sludge comprises the following steps:

[0034] S1. Utilize the gradually settling activated sludge and adsorbent to contact the gradually rising sewage in reverse, so that the pollutants in the sewage are adsorbed and retained and form a sludge mixture with the activated sludge and then settle together;

[0035] S2. Using anaerobic sludge to carry out anaerobic biochemical treatment on the sludge mixture containing a large amount of organic matter to remove the organic matter, generate methane and recover it;

[0036] S3, performing anaerobic ammonium oxidation treatment on the effluent mixture formed after the treatment in step S2 using anaerobic ammonium oxidation sludge (ANAMMOX), so as to convert ammonia nitrogen in the effluent mixture into nitrogen gas, thereby achieving denitrification;

[0037] S4, performing aerobic recovery treatment on the effluent mixture formed after the treatment in step S3 to restore the activity of the activated sludge in the effluent mixture and remove residual organic matter;

[0038] S5, the impurities in the effluent mixture formed after the treatment in step S4 are discharged as excess sludge, and the activated sludge that has recovered its activity is returned to step S1 to participate in the circulation;

[0039] S6. Based on the cycle of S1-S5, the wastewater treated in step S1 is discharged after chemical dephosphorization and disinfection.

[0040] In the present invention, the sewage is domestic sewage that has not been treated in a septic tank, the COD concentration in the sewage reaches 400-600 mg / L, and the COD is mainly undissolved particulate matter.

[0041] In this invention, the activated sludge in step S1 is gray flocculent, the anaerobic sludge in step S2 is black granular, and the anaerobic ammonium oxidation sludge (ANAMMOX) in step S3 is red granular, forming a three-color sludge system. In this three-color sludge process, the gray sludge filters and adsorbs the raw sewage, trapping particulate pollutants and adsorbing ammonia. This increases COD and ammonia nitrogen concentrations several times, and then undergoes anaerobic biological treatment to recover methane. After anaerobic black sludge treatment, the COD concentration of the raw water is significantly reduced. Anaerobic ammonium oxidation is then carried out with red sludge. After ammonia removal, the sewage undergoes chemical phosphorus removal and disinfection, resulting in purified wastewater.

[0042] Step S1 is performed using a countercurrent adsorption tower (column), the core of the process. Sewage water enters the tower from the bottom and exits from the top. Returning activated sludge enters from the top, and the settled sludge mixture exits from the bottom. The flow rates are related to each other in the following manner: the return activated sludge flow rate equals the discharge flow rate of the mixture from the bottom, and the incoming sewage water flow rate from the bottom equals the outgoing water flow rate from the top. Within this reactor, the returning sludge continuously sinks, forcing the incoming water upward. The two interact in countercurrent, adsorbing and trapping various pollutants in the raw water. To ensure effective ammonia nitrogen adsorption and sludge settling, the process requires the regular addition of a powdered ammonia adsorbent, such as powdered zeolite.

[0043] Furthermore, the SS concentration within the countercurrent adsorption tower (column) is 6,000-12,000 mg / L. If the SS concentration is too low, the countercurrent contact adsorption effect will be poor. If the SS concentration is too high, sedimentation will be difficult and the sedimentation time will be too long, leading to anaerobic conditions within the countercurrent contact tower reactor and process failure. Furthermore, within the reactor, since the sludge sinks by gravity, a certain area below the reactor is a sludge layer, while the upper area is a clear water layer. Therefore, the reactor height should not be too small; the net height of the effective sedimentation zone should be no less than 3 meters, and the sludge sedimentation time should be 0.5-1.5 hours.

[0044] The specific process of step S3 is as follows: the effluent mixture after the treatment in step S2 is equally divided into two parts and discharged, 50% of the effluent mixture is subjected to aerobic nitrification treatment to convert ammonia nitrogen in the effluent mixture into nitrite, and then the remaining 50% of the effluent mixture and the effluent mixture after the aerobic nitrification treatment are subjected to anaerobic ammonium oxidation treatment using anaerobic ammonium oxidation sludge to convert ammonia nitrogen in the effluent mixture into nitrogen gas.

[0045] In the present invention, slight stirring is performed during the anaerobic biochemical treatment process in step S2 and the anaerobic ammonium oxidation treatment process in step S3 to prevent the activated sludge in the mixture from being trapped by the anaerobic sludge and the anaerobic ammonium oxidation sludge, thereby accelerating mass transfer and increasing the reaction rate. Aeration is performed during the aerobic nitritation treatment process in step S3 and the aerobic recovery treatment process in step S4, and stirring is performed during the aerobic recovery treatment process in step S4 to form an annular flow field. In addition, both aerobic reactors require fillers.

[0046] The present invention also provides a system for implementing the above method, the system comprising:

[0047] The countercurrent adsorption tower (column) A is used to utilize the gradually settling activated sludge and adsorbent to contact the gradually rising sewage in the reverse direction, so that the pollutants in the sewage are adsorbed and retained and form a sludge mixture with the activated sludge and then settle together; the upper part of the countercurrent adsorption tower (column) is provided with a water outlet for purified water and a reflux port for activated sludge, and the lower part of the countercurrent adsorption tower (column) is provided with a water inlet for sewage and a discharge port for the mixture.

[0048] The anaerobic reactor B is used to perform anaerobic biochemical treatment on a sludge mixture containing a large amount of organic matter using anaerobic sludge to remove the organic matter, generate methane and recover it; the lower part of the anaerobic reactor is provided with an inlet for the mixture, and the upper part is provided with two outlets, each for discharging part of the treated mixture.

[0049] The anaerobic ammonium oxidation reaction unit is used to perform anaerobic ammonium oxidation treatment on the effluent mixture using anaerobic ammonium oxidation sludge (ANAMMOX) to convert ammonia nitrogen in the effluent mixture into nitrogen gas, thereby achieving denitrification. The anaerobic ammonium oxidation reaction unit is composed of an aerobic nitritation reactor D and an anaerobic ammonium oxidation reactor C. The aerobic nitritation reactor is connected to one of the outlets of the anaerobic reactor and is used to perform aerobic nitritation treatment on the effluent mixture to convert ammonia nitrogen in the effluent mixture into nitrite. The anaerobic ammonium oxidation reactor is connected to the other outlet of the anaerobic reactor and the outlet of the aerobic nitritation reactor at the same time and is used to perform anaerobic ammonium oxidation treatment on the effluent mixture using anaerobic ammonium oxidation sludge to convert ammonia nitrogen in the effluent mixture into nitrogen gas.

[0050] The aerobic recovery reactor E is used to perform aerobic recovery treatment on the effluent mixture, repair the broken flocs of the sludge, so as to restore the activity of the activated sludge in the effluent mixture and remove the residual organic matter; after passing through the aerobic recovery reactor, the activated sludge is restored to a gray floc state and flows back to the countercurrent adsorption tower (column), completing the cycle.

[0051] The countercurrent adsorption tower (column), anaerobic reactor, anaerobic ammonium oxidation reaction unit and aerobic recovery reactor are sequentially connected through a mixture pipeline, and an activated sludge return pipeline is provided between the aerobic recovery reactor and the countercurrent adsorption tower (column), and several pumps are provided in the system.

[0052] In addition, aerobic reactors all require fillers. The anaerobic granular sludge is black, and the particle size is generally several millimeters, so it can settle at the bottom of the reactor. The black anaerobic granular sludge does not participate in the circulation and only remains in this reactor; the sludge in the anaerobic ammonium oxidation reactor is red, and the particle size is generally several millimeters, so it can settle at the bottom of the reactor. The red, granular anaerobic ammonium oxidation sludge does not participate in the circulation and only remains in this reactor. Therefore, neither the anaerobic black reactor nor the anaerobic ammonium oxidation reactor can be stirred violently, but only slightly. On the one hand, it accelerates mass transfer and increases the reaction rate, and on the other hand, it avoids the retention of activated sludge. The aerobic nitrification reactor used for ammonia oxidation only uses aeration as stirring. In addition to aeration, the aerobic reactor used for sludge recovery also requires a certain horizontal annular flow at the bottom of the reactor, so an agitator is also required.

[0053] The principle of this system is: based on the characteristics that the organic matter of the original domestic sewage mainly comes from feces with less dissolved organic matter, when the domestic sewage is not set up in a septic tank, the COD concentration of the raw water can reach 500-600 mg / L, and the COD is mainly particulate matter, that is, the dissolved COD concentration is not high. For such domestic sewage raw water, if it is mixed with activated sludge for precipitation, and then supplemented with powdered ammonia adsorbent and Fe with flocculation performance, 3+ If the raw water and mixed activated sludge are free of salt, the majority of the particulate organic matter, ammonia nitrogen, and surfactants in the raw water are precipitated after sedimentation. The wastewater is then chemically treated to remove phosphorus, achieving a significant degree of purification (meeting discharge standards). Further disinfection is required before discharge. The precipitated, high-concentration mixture (activated sludge, ammonia nitrogen, insoluble phosphorus, suspended solids, and added adsorbent) undergoes anaerobic and anaerobic ammonium oxidation treatments, converting organic matter into methane for recycling and ammonia into nitrogen. The remaining small amount of organic matter is then removed aerobically, restoring the activated sludge's cohesive properties. In addition to aeration, the terminal aerobic tank also requires a certain amount of horizontal annular flow. By regulating and controlling these hydraulic conditions, residual fine sand, large, non-degradable particles, and chemical sludge are gradually concentrated to the center of the tank bottom under the action of secondary flow. This mixed impurity is then discharged as residual sludge.

[0054] It should be noted that the proportion of organic matter in the raw water that can be used to grow aerobic activated sludge is relatively small. Even with minimal or no sludge discharge, maintaining the amount of activated sludge in the system requires a low raw water COD concentration. Taking into account factors such as the properties of the activated sludge and its metabolic characteristics (yield coefficient), the influent COD concentration should not be lower than 400 mg / L. If the COD concentration of the wastewater after the septic tank is removed is significantly lower than this value, this process is not suitable for treatment. Furthermore, the HRT of both aerobic reactors should not be too long; an HRT of 1-2 hours is ideal.

[0055] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A low-carbon emission sewage treatment method based on three-color sludge, the method is for sewage that has not been treated in a septic tank, and the organic matter in the sewage is mainly particulate organic matter, characterized in that: The method steps include: S1. Utilize the gradually settling activated sludge and adsorbent to contact the gradually rising sewage in reverse, so that the pollutants in the sewage are adsorbed and retained and form a sludge mixture with the activated sludge and then settle together; S2. Using anaerobic sludge to perform anaerobic biochemical treatment on the sludge mixture containing organic matter to remove the organic matter therein, generate methane and recover it; S3, using anaerobic ammonium oxidation sludge to treat the effluent mixture formed after the treatment in step S2, so as to convert ammonia nitrogen in the sewage into nitrogen gas, thereby achieving denitrification; S4, performing aerobic recovery treatment on the effluent mixture formed after the treatment in step S3 to restore the activity and adsorption performance of the activated sludge therein and further remove residual organic matter; S5, the impurities treated in step S4 are discharged as excess sludge, and the activated sludge that has recovered its activity is returned to step S1 to participate in the cycle; S6. Based on the cycle of S1-S5, the wastewater treated in step S1 is discharged after chemical dephosphorization and disinfection.

2. A low-carbon emission sewage treatment method based on three-color sludge according to claim 1, characterized in that: The COD concentration in the sewage reaches 500-600 mg / L.

3. The low-carbon emission sewage treatment method based on three-color sludge according to claim 1 is characterized in that: The activated sludge in step S1 is in the form of gray flocs, the anaerobic sludge in step S2 is in the form of black granules, and the anaerobic ammonium oxidation sludge in step S3 is in the form of red granules.

4. The low-carbon emission sewage treatment method based on three-color sludge according to claim 1 is characterized in that: Step S1 is carried out using a countercurrent adsorption tower, with the raw sewage water entering from the lower part of the tower body and the water discharged from the upper part of the tower body; the returned activated sludge enters from the upper part of the tower body, and the settled sludge mixture is discharged from the lower part of the tower body, and the relationship between the flow rates is: the upper return activated sludge flow rate is equal to the discharge flow rate of the lower mixture, and the lower sewage raw water entry flow rate is equal to the upper outlet flow rate.

5. A low-carbon emission sewage treatment method based on three-color sludge according to claim 4, characterized in that: The SS concentration in the countercurrent adsorption tower is 6000-12000 mg / L, the net height of the effective sedimentation area is not less than 3m, and the sludge sedimentation time is 0.5-1.5h.

6. The low-carbon emission sewage treatment method based on three-color sludge according to claim 1 is characterized in that: The specific process of step S3 is as follows: the effluent mixture formed after the treatment in step S2 is equally discharged in two parts, 50% of the effluent mixture is subjected to aerobic nitrification treatment to convert ammonia nitrogen in the effluent mixture into nitrite, and then the remaining 50% of the effluent mixture and the effluent mixture after the aerobic nitrification treatment are subjected to anaerobic ammonium oxidation treatment using anaerobic ammonium oxidation sludge to convert ammonia nitrogen in the effluent mixture into nitrogen gas.

7. A low-carbon emission sewage treatment method based on three-color sludge according to claim 6, characterized in that: During the anaerobic biochemical treatment process of step S2 and the anaerobic ammonium oxidation treatment process of step S3, slight stirring is performed to prevent the activated sludge in the mixture from being entrapped by the anaerobic sludge and the anaerobic ammonium oxidation sludge, resulting in poor sludge external circulation; during the aerobic nitritation treatment process of step S3 and the aerobic recovery treatment process of step S4, aeration is performed, and stirring is performed during the aerobic recovery treatment process of step S4 to form an annular flow field.

8. The low-carbon emission sewage treatment method based on three-color sludge according to claim 6 is characterized in that: During the aerobic nitritation treatment in step S3 and the aerobic recovery treatment in step S4, the hydraulic retention time HRT is 1-2 hours.

9. A system for implementing the low-carbon emission sewage treatment method based on three-color sludge according to any one of claims 1 to 8, characterized in that: The system comprises: The countercurrent adsorption tower is used to utilize the gradually settling activated sludge and adsorbent mixture to contact the gradually rising sewage in the reverse direction, so that the pollutants in the sewage are adsorbed and retained and form a sludge mixture with the activated sludge and then settle together; Anaerobic reactor, which uses anaerobic sludge to carry out anaerobic biochemical treatment on the sludge mixture containing organic matter to remove the organic matter, produce methane and recover it; The anaerobic ammonium oxidation reaction unit uses anaerobic ammonium oxidation sludge to treat the effluent mixture, so as to convert the ammonia nitrogen in the sewage into nitrogen gas and achieve denitrification; Aerobic recovery reactor, which performs aerobic recovery treatment on the effluent mixture to restore the activity and adsorption performance of the activated sludge and further remove residual organic matter; The countercurrent adsorption tower, the anaerobic reactor, the anaerobic ammonium oxidation reaction unit and the aerobic recovery reactor are sequentially connected through a mixture pipeline, and an activated sludge return pipeline is provided between the aerobic recovery reactor and the countercurrent adsorption tower.

10. The system according to claim 9, characterized in that The anaerobic ammonium oxidation reaction unit comprises: an aerobic nitritation reactor, used for performing an ammonia oxidation treatment on the mixture to convert ammonia nitrogen in the mixture into nitrite nitrogen; The anaerobic ammonium oxidation reactor is used to perform anaerobic ammonium oxidation treatment on the mixture using anaerobic ammonium oxidation sludge, so as to convert ammonia nitrogen in the mixture into nitrogen gas.

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