Sewage treatment system

Abstract

The present invention relates to the field of water treatment, and specifically provides a sewage treatment system. The sewage treatment system includes a water inlet pipe, a first MABR treatment unit, a second MABR treatment unit, a third MABR treatment unit, and a reflux pipe. Both the first MABR treatment unit and the second MABR treatment unit are connected between the water inlet pipe and the third MABR treatment unit, and the first MABR treatment unit and the second MABR treatment unit are arranged in parallel. The reflux pipe is connected between the outlet end of the first MABR treatment unit and the inlet end of the second MABR treatment unit. The sewage treatment system of the present invention can supply sewage to both the first MABR treatment unit and the second MABR treatment unit simultaneously, and then enter the third MABR treatment unit. It can also supply a small part of the sewage with a high C / N to the second MABR treatment unit and most of it to the first MABR treatment unit. The effluent of the first MABR treatment unit is supplied to the second MABR treatment unit through the reflux pipe, and the effluent of the second MABR treatment unit enters the third MABR treatment unit, thus having a high sewage treatment effect and sewage adaptability.

Description

Technical Field

[0001] The present invention relates to the field of water treatment, and particularly to a sewage treatment system. Background Art

[0002] MABR is a sewage treatment technology that combines gas membrane technology and biofilm technology. In related technologies, an MABR sewage treatment system includes a plurality of serially connected MABR treatment units. Sewage sequentially passes through the plurality of serially connected MABR treatment units and undergoes reactions, thereby achieving sewage treatment.

[0003] However, since the amount of bacteria in each MABR treatment unit is within a certain range, the amount of inorganic substances and organic substances in the sewage treated by it also needs to be maintained within a certain range. However, the amount of inorganic substances and organic substances in actual sewage fluctuates greatly and it is difficult to always maintain within the required range. Therefore, there are problems of poor sewage treatment effect and poor adaptability of the system to sewage. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related technologies to some extent. For this purpose, the present invention provides a sewage treatment system, which has a high sewage treatment effect and high adaptability to sewage.

[0005] The sewage treatment system of the present invention includes a water inlet pipe, a first MABR treatment unit, a second MABR treatment unit, a third MABR treatment unit, and a reflux pipe. Both the first MABR treatment unit and the second MABR treatment unit are connected between the water inlet pipe and the third MABR treatment unit, and the first MABR treatment unit and the second MABR treatment unit are arranged in parallel. The flow rate of the water inlet pipe entering the first MABR treatment unit and the flow rate of the second MABR treatment unit are adjustable. The reflux pipe is connected between the outlet end of the first MABR treatment unit and the inlet end of the second MABR treatment unit. The flow rate of the first MABR treatment unit entering the third MABR treatment unit and the flow rate of the reflux pipe are adjustable.

[0006] Further, the sewage treatment system further includes a fourth MABR treatment unit, and the fourth MABR treatment unit is connected in series between the second MABR treatment unit and the third MABR treatment unit. The serially connected second MABR treatment unit and the fourth MABR treatment unit are arranged in parallel with the first MABR treatment unit.

[0007] Further, there are multiple groups of the serially connected second MABR treatment unit and the fourth MABR treatment unit, and multiple groups of the second MABR treatment unit and the fourth MABR treatment unit are arranged in parallel; and / or

[0008] The water inlet pipe includes a first branch and a second branch with adjustable flow rates. The first branch is connected to the first MABR treatment unit and the second MABR treatment unit with adjustable flow rates, and the second branch is connected to the first MABR treatment unit and the fourth MABR treatment unit with adjustable flow rates.

[0009] Further, the first MABR treatment unit, the second MABR treatment unit, the third MABR treatment unit, and the fourth MABR treatment unit each include a membrane tank, an MABR membrane module, and a circulation channel. The MABR membrane module is disposed in the corresponding membrane tank, and the circulation channel is connected between the outlet end and the inlet end of the corresponding membrane tank. The membrane tank of the second MABR treatment unit is connected to the corresponding circulation channel and the fourth MABR treatment unit with adjustable flow rates, and the membrane tank of the fourth MABR treatment unit is connected to the corresponding circulation channel and the third MABR treatment unit with adjustable flow rates.

[0010] Further, the circulation channel is provided with an interface. The first MABR treatment unit, the second MABR treatment unit, the third MABR treatment unit, and the fourth MABR treatment unit also each include an aeration pump and a gas-lift device. The aeration pump is connected to the air inlet of the corresponding MABR membrane module, the gas-lift device is connected to the air outlet of the corresponding MABR membrane module, and the gas-lift device is also connected to the interface of the corresponding circulation channel.

[0011] Further, the first MABR treatment unit, the second MABR treatment unit, the third MABR treatment unit, and the fourth MABR treatment unit satisfy:

[0012] The allowable influent C / N of the second MABR treatment unit ≥ the allowable influent C / N of the fourth MABR treatment unit ≥ the allowable influent C / N of the third MABR treatment unit;

[0013] The MABR membrane packing density of the fourth MABR treatment unit ≥ the MABR membrane packing density of the third MABR treatment unit ≥ the MABR membrane packing density of the second MABR treatment unit ≥ the MABR membrane packing density of the first MABR treatment unit;

[0014] The hydraulic retention time of the second MABR treatment unit ≥ the hydraulic retention time of the fourth MABR treatment unit. The hydraulic retention time of the fourth MABR treatment unit is greater than the hydraulic retention time of the first MABR treatment unit, and the hydraulic retention time of the fourth MABR treatment unit is greater than the hydraulic retention time of the third MABR treatment unit;

[0015] The biofilm thickness of the first MABR treatment unit is 600 μm to 900 μm, the biofilm thickness of the second MABR treatment unit is 650 μm to 900 μm, the biofilm thickness of the fourth MABR treatment unit is 400 μm to 500 μm, and the biofilm thickness of the third MABR treatment unit is 300 μm to 450 μm;

[0016] The dissolved oxygen concentration of the first MABR treatment unit is less than 0.3 mg / L, the dissolved oxygen concentration of the second MABR treatment unit is less than 0.2 mg / L, the dissolved oxygen concentration of the fourth MABR treatment unit is less than 0.1 mg / L, and the dissolved oxygen concentration of the third MABR treatment unit is less than 0.1 mg / L;

[0017] at least one of them.

[0018] Further, the sewage treatment system further includes a carbon and phosphorus capture unit and an extreme phosphorus capture unit. The outlet end of the carbon and phosphorus capture unit is connected to the inlet end of the water inlet pipe, and the inlet end of the extreme phosphorus capture unit is connected to the outlet end of the third MABR treatment unit.

[0019] Further, the sewage treatment system further includes:

[0020] An anaerobic digestion sludge bed for receiving the sludge produced by the carbon and phosphorus capture unit. The anaerobic digestion sludge bed is connected to the carbon and phosphorus capture unit to supply the supernatant produced to the carbon and phosphorus capture unit;

[0021] A sludge thermal hydrolysis unit for receiving the sludge produced by the extreme phosphorus capture unit and the sludge produced by the anaerobic digestion sludge bed;

[0022] A phosphorus recovery unit connected between the outlet end of the sludge thermal hydrolysis unit and the inlet end of the anaerobic digestion sludge bed.

[0023] Further, the sewage treatment system further includes at least one of a cogeneration unit, a water source heat pump unit, a hydropower generation unit, and a photovoltaic unit;

[0024] The cogeneration unit is connected to the anaerobic digestion sludge bed to receive the methane produced by the anaerobic digestion sludge bed, and the cogeneration unit is connected to the sludge thermal hydrolysis unit to supply heat to the sludge thermal hydrolysis unit;

[0025] The water source heat pump unit is used to obtain the temperature difference heat formed by the effluent of the extreme phosphorus capture unit. The water source heat pump unit is connected to the cogeneration unit and / or the sludge thermal hydrolysis unit to supply heat to the cogeneration unit and / or the sludge thermal hydrolysis unit;

[0026] The hydroelectric power generation unit is used to obtain the potential energy formed by the effluent of the extreme phosphorus capture unit and generate electricity;

[0027] The photovoltaic unit is connected to the cogeneration unit and / or the sludge hydrothermal hydrolysis unit to supply heat to the cogeneration unit and / or the sludge hydrothermal hydrolysis unit.

[0028] Furthermore, the sewage treatment system further includes at least one of a multi-stage grille unit, a disinfection unit, and a sludge dewatering unit;

[0029] The outlet end of the multi-stage grille unit is connected to the inlet end of the carbon and phosphorus capture unit, and the anaerobic digestion sludge bed is connected to the multi-stage grille unit to supply the generated supernatant to the multi-stage grille unit;

[0030] The inlet end of the disinfection unit is connected to the outlet end of the extreme phosphorus capture unit. The water source heat pump unit is used to obtain the temperature difference heat formed by the effluent of the disinfection unit, and the hydroelectric power generation unit is used to obtain the potential energy formed by the effluent of the disinfection unit and generate electricity;

[0031] The sludge dewatering unit is used to receive the sludge generated by the sludge hydrothermal hydrolysis unit.

[0032] The sewage treatment system of the present invention can supply sewage through the water inlet pipe to the first MABR treatment unit and the second MABR treatment unit for treatment simultaneously, and then enter the third MABR treatment unit for treatment and discharge. When the C / N of the sewage is relatively high, a small part of the sewage can be supplied to the second MABR treatment unit, and most of the sewage can be supplied to the first MABR treatment unit. The effluent of the first MABR treatment unit is refluxed to the second MABR treatment unit through the reflux pipe for re-treatment, and the effluent of the second MABR treatment unit enters the third MABR treatment unit for treatment and discharge, thereby having a high sewage treatment effect and sewage adaptability. Description of the Drawings

[0033] Figure 1 is a schematic diagram of the sewage treatment system according to an embodiment of the present invention.

[0034] Reference Numerals:

[0035] 1. Water inlet pipe; 101. First branch; 102. Second branch; 2. First MABR treatment unit; 3. Second MABR treatment unit; 4. Third MABR treatment unit; 5. Fourth MABR treatment unit; 6. Carbon and phosphorus capture unit; 7. Extreme phosphorus capture unit; 8. Anaerobic digestion sludge bed; 9. Sludge thermal hydrolysis unit; 10. Phosphorus recovery unit; 11. Cogeneration unit; 12. Water source heat pump unit; 13. Photovoltaic unit; 14. Multi-stage grille unit; 15. Disinfection unit; 16. Sludge dewatering unit. Detailed implementation manners

[0036] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0037] Reference will be made below Figure 1 to describe a sewage treatment system according to an embodiment of the present invention.

[0038] As Figure 1 shown, the sewage treatment system according to an embodiment of the present invention includes a water inlet pipe 1, a first MABR treatment unit 2, a second MABR treatment unit 3, a third MABR treatment unit 4, and a reflux pipe (not shown in the figure).

[0039] Both the first MABR treatment unit 2 and the second MABR treatment unit 3 are connected between the water inlet pipe 1 and the third MABR treatment unit 4, and the first MABR treatment unit 2 and the second MABR treatment unit 3 are arranged in parallel. The flow rates of the water inlet pipe 1 entering the first MABR treatment unit 2 and the second MABR treatment unit 3 are adjustable. The reflux pipe is connected between the outlet end of the first MABR treatment unit 2 and the inlet end of the second MABR treatment unit 3, and the flow rates of the first MABR treatment unit 2 entering the third MABR treatment unit 4 and the reflux pipe are adjustable.

[0040] Specifically, as Figure 1 shown, the water inlet pipe 1 is used to supply sewage. The first MABR treatment unit 2, the second MABR treatment unit 3, and the third MABR treatment unit 4 are all used to treat sewage. The first MABR treatment unit 2 also plays a role in resisting water quality shock load. Further, the first MABR treatment unit 2 also plays a role in resisting water volume shock load.

[0041] Both the first MABR treatment unit 2 and the second MABR treatment unit 3 are connected between the water inlet pipe 1 and the third MABR treatment unit 4, and the first MABR treatment unit 2 and the second MABR treatment unit 3 are arranged in parallel. The water inlet pipe 1 supplies sewage to the first MABR treatment unit 2 and the second MABR treatment unit 3 for treatment respectively, and then enters the third MABR treatment unit 4 for further treatment and discharge.

[0042] The reflux pipe is connected between the outlet end of the first MABR treatment unit 2 and the inlet end of the second MABR treatment unit 3 to guide the effluent treated by the first MABR treatment unit 2 back to the second MABR treatment unit 3 for further treatment. Preferably, a water pump is provided on the reflux pipe.

[0043] A corresponding valve body is provided between the water inlet pipe 1 and the first MABR treatment unit 2 to make the flow rate of the water inlet pipe 1 into the first MABR treatment unit 2 adjustable. A corresponding valve body is provided between the water inlet pipe 1 and the second MABR treatment unit 3 to make the flow rate of the water inlet pipe 1 into the second MABR treatment unit 3 adjustable.

[0044] The inlet end of the reflux pipe is preferably arranged on the pipeline connecting the first MABR treatment unit 2 and the third MABR treatment unit 4. A corresponding valve body is provided on the pipeline connecting the first MABR treatment unit 2 and the third MABR treatment unit 4 and is located downstream of the inlet end of the reflux pipe along the direction of the medium flowing from the first MABR treatment unit 2 to the third MABR treatment unit 4 to make the flow rate of the first MABR treatment unit 2 into the third MABR treatment unit 4 adjustable. A corresponding valve body is provided on the reflux pipe to make the flow rate of the first MABR treatment unit 2 into the reflux pipe adjustable.

[0045] It should be noted that the adjustable flow rate includes that the corresponding pipeline can be adjusted between the opening and closing states. Further, the adjustable flow rate also includes adjusting the flow rate between multiple stages.

[0046] The sewage treatment system of the embodiment of the present invention includes at least two states.

[0047] In the first state, sewage is simultaneously supplied to the first MABR treatment unit 2 and the second MABR treatment unit 3 through the water inlet pipe 1 for treatment. Preferably, the flow rate of the sewage supplied to the first MABR treatment unit 2 is the same as the flow rate of the sewage supplied to the second MABR treatment unit 3. In other words, the sewage is evenly distributed to the first MABR treatment unit 2 and the second MABR treatment unit 3. The sewage treated by the first MABR treatment unit 2 and the second MABR treatment unit 3 respectively enters the third MABR treatment unit 4 for treatment and discharge. The reflux pipe is preferably in a closed state in the first state.

[0048] In the second state, the sewage is distributed through the water inlet pipe 1. A small portion of the sewage is fed into the second MABR treatment unit 3, and most of the sewage is fed into the first MABR treatment unit 2 for treatment. Preferably, the amount of sewage fed into the first MABR treatment unit 2 is 75% - 90% of the sewage volume in the water inlet pipe 1, and the remaining part is fed into the second MABR treatment unit 3 to ensure the stable C / N of the influent water for other MABR treatment units except the first MABR treatment unit 2, and to ensure the stable living environment for the corresponding microorganisms required by other MABR treatment units, with strong competitiveness. The pipeline connecting the first MABR treatment unit 2 and the third MABR treatment unit 4 is closed, and the reflux pipe is opened. The effluent water treated by the first MABR treatment unit 2 is refluxed to the second MABR treatment unit 3 through the reflux pipe. The sewage refluxed to the second MABR treatment unit 3 and the sewage fed into the second MABR treatment unit 3 by the water inlet pipe 1 are simultaneously treated in the second MABR treatment unit 3, and then fed into the third MABR treatment unit 4 for treatment and discharge.

[0049] When the carbon-nitrogen ratio C / N of the sewage is normal, the sewage treatment system is in the first state. When there is a water quality shock load in the sewage, in other words, when the C / N of the sewage is relatively high, the sewage treatment system is in the second state. When there is a water volume shock load in the sewage, in other words, when the water volume of the sewage increases, the sewage treatment system can be in the first state, and most of the sewage is fed into the first MABR treatment unit 2 through the water inlet pipe 1. The reflux pipe can be opened or closed, and the sewage treatment system can also be in the second state. Preferably, the sewage capacity of the first MABR treatment unit 2 is greater than that of the second MABR treatment unit 3.

[0050] Through at least the first state and the second state of the sewage treatment system, it is ensured that the effluent water of the third MABR treatment unit 4 has a lower chemical oxygen demand, ammonia nitrogen content, and total nitrogen content, enabling the sewage treatment system to have a higher sewage treatment effect. At the same time, the sewage treatment system can be applicable to sewage with a larger C / N value range and greater C / N fluctuations, with higher adaptability to sewage and the ability to treat various types of sewage.

[0051] In some embodiments, the sewage treatment system of the embodiment of the present invention further includes a fourth MABR treatment unit 5. The fourth MABR treatment unit 5 is connected in series between the second MABR treatment unit 3 and the third MABR treatment unit 4, and the second MABR treatment unit 3 and the fourth MABR treatment unit 5 connected in series are arranged in parallel with the first MABR treatment unit 2.

[0052] As Figure 1As shown, the fourth MABR treatment unit 5 is also used to treat sewage. The fourth MABR treatment unit 5 is connected in series between the second MABR treatment unit 3 and the third MABR treatment unit 4 through pipelines. The effluent treated by the second MABR treatment unit 3 first enters the fourth MABR treatment unit 5 for treatment, and then enters the third MABR treatment unit 4 for treatment.

[0053] The second MABR treatment unit 3 and the fourth MABR treatment unit 5 connected in series are arranged in parallel with the first MABR treatment unit 2. In other words, between the water inlet pipe 1 and the fourth MABR treatment unit 5, the first MABR treatment unit 2 is arranged in parallel with the second MABR treatment unit 3 and the fourth MABR treatment unit 5 connected in series. To ensure the sewage treatment effect and sewage adaptability of the sewage treatment system.

[0054] In some embodiments, there are multiple groups of the second MABR treatment unit 3 and the fourth MABR treatment unit 5 connected in series, and multiple groups of the second MABR treatment unit 3 and the fourth MABR treatment unit 5 are arranged in parallel.

[0055] As Figure 1 shown, both the second MABR treatment unit 3 and the fourth MABR treatment unit 5 are multiple, and the second MABR treatment unit 3 and the fourth MABR treatment unit 5 are connected in series one by one to form groups, and multiple groups of the second MABR treatment unit 3 and the fourth MABR treatment unit 5 connected in series are arranged in parallel, preferably four groups arranged in parallel. In other words, both the second MABR treatment unit 3 and the fourth MABR treatment unit 5 are four. So that the sewage treatment system can handle a larger range of sewage flow rates and can bear a greater water volume impact load.

[0056] At the same time, the sewage treatment system can also close any group of the second MABR treatment unit 3 and the fourth MABR treatment unit 5 or adjust it to a smaller flow rate to maintain and repair this group of the second MABR treatment unit 3 and the fourth MABR treatment unit 5. Further, the first MABR treatment unit 2 can also be closed or adjusted to a smaller flow rate to maintain and repair the first MABR treatment unit 2, so as to ensure the continuous normal operation of the sewage treatment system and avoid the need for the sewage treatment system to suspend sewage treatment.

[0057] In some embodiments, the water inlet pipe 1 includes a first branch 101 and a second branch 102 with adjustable flow rates. The first branch 101 is connected to the first MABR treatment unit 2 and the second MABR treatment unit 3 with adjustable flow rates, and the second branch 102 is connected to the first MABR treatment unit 2 and the fourth MABR treatment unit 5 with adjustable flow rates.

[0058] As Figure 1As shown in the figure, the water inlet pipe 1 includes a first branch 101 and a second branch 102. The inlet ends of the first branch 101 and the second branch 102 are each provided with a corresponding valve body so that the sewage flow rates entering the first branch 101 and the second branch 102 are adjustable. Preferably, the first branch 101 and the second branch 102 can be opened and closed respectively through the corresponding valve bodies so that the sewage flow direction can be switched between the first branch 101 and the second branch 102.

[0059] The first branch 101 is simultaneously connected to the first MABR treatment unit 2 and a plurality of second MABR treatment units 3. A corresponding valve body is provided between the first branch 101 and the first MABR treatment unit 2 to adjust the sewage flow rate entering the first MABR treatment unit 2, and a corresponding valve body is provided between the first branch 101 and each second MABR treatment unit 3 to adjust the sewage flow rate entering the second MABR treatment unit 3.

[0060] The second branch 102 is simultaneously connected to the first MABR treatment unit 2 and a plurality of fourth MABR treatment units 5. A corresponding valve body is provided between the second branch 102 and the first MABR treatment unit 2 to adjust the sewage flow rate entering the first MABR treatment unit 2, and a corresponding valve body is provided between the second branch 102 and each fourth MABR treatment unit 5 to adjust the sewage flow rate entering the fourth MABR treatment unit 5.

[0061] According to the C / N and type of the sewage, the sewage can be supplied to the first MABR treatment unit 2 and a plurality of second MABR treatment units 3 through the first branch 101, including the first state and the second state of the sewage treatment system. The effluents of the plurality of second MABR treatment units 3 are respectively supplied to a plurality of fourth MABR treatment units 5 and then supplied to the third MABR treatment unit 4.

[0062] Alternatively, the sewage can be supplied to the first MABR treatment unit 2 and a plurality of fourth MABR treatment units 5 through the second branch 102. At this time, it is the third state of the sewage treatment system. The sewage is supplied to the first MABR treatment unit 2 and a plurality of fourth MABR treatment units 5 through the second branch 102. The effluents of the plurality of fourth MABR treatment units 5 and the effluent of the first MABR treatment unit 2 are simultaneously supplied to the third MABR treatment unit 4 for treatment and discharge, and the reflux pipe is preferably in a closed state.

[0063] Furthermore, in the third state, a small amount of sewage can also be supplied to a plurality of second MABR treatment units 3 through the first branch 101 to ensure the survival of bacteria in the second MABR treatment units 3.

[0064] In some embodiments, the first MABR treatment unit 2, the second MABR treatment unit 3, the third MABR treatment unit 4, and the fourth MABR treatment unit 5 each include a membrane tank, an MABR membrane module, and a circulation channel. The MABR membrane module is disposed in the corresponding membrane tank, and the circulation channel is connected between the outlet end and the inlet end of the corresponding membrane tank. The membrane tank of the second MABR treatment unit 3 is adjustably connected to the corresponding circulation channel and the fourth MABR treatment unit 5, and the membrane tank of the fourth MABR treatment unit 5 is adjustably connected to the corresponding circulation channel and the third MABR treatment unit 4.

[0065] Specifically, the first MABR treatment unit 2, the second MABR treatment unit 3, the third MABR treatment unit 4, and the fourth MABR treatment unit 5 each include a membrane tank, an MABR membrane module, and a circulation channel.

[0066] The membrane tank is used to hold sewage, and the membrane tank is preferably provided with a slag discharge port and a vent port. The MABR membrane module is disposed in the membrane tank of the same MABR treatment unit for treating sewage. The MABR membrane module includes at least one of a hollow fiber membrane, a plate membrane, a spiral wound membrane, and a tubular membrane. The circulation channel can be disposed in the membrane tank of the same MABR treatment unit or outside the membrane tank of the same MABR treatment unit. The inlet end of the circulation channel is connected to the outlet end of the membrane tank of the same MABR treatment unit, and the outlet end of the circulation channel is connected to the inlet end of the membrane tank of the same MABR treatment unit. The effluent of the membrane tank can flow back to the inlet end of the membrane tank through the circulation channel of the same MABR treatment unit, so that the sewage can circulate and be treated in the membrane tank and the circulation channel.

[0067] Preferably, a corresponding valve body is provided on the pipeline connecting the membrane tank of the second MABR treatment unit 3 and the membrane tank of the fourth MABR treatment unit 5 to at least control the flow on-off between the membrane tank of the second MABR treatment unit 3 and the membrane tank of the fourth MABR treatment unit 5. The inlet end of the circulation channel of the second MABR treatment unit 3 is disposed on the pipeline connecting the membrane tank of the second MABR treatment unit 3 and the membrane tank of the fourth MABR treatment unit 5 and is located upstream of the corresponding valve body on the pipeline along the flow direction of the sewage from the second MABR treatment unit 3 to the fourth MABR treatment unit 5, so that the membrane tank of the second MABR treatment unit 3 is adjustably connected to the corresponding circulation channel and the fourth MABR treatment unit 5. When the valve body on the pipeline connecting the membrane tank of the second MABR treatment unit 3 and the membrane tank of the fourth MABR treatment unit 5 is closed, the sewage circulates and is repeatedly treated in the membrane tank and the circulation channel of the second MABR treatment unit 3 until the C / N of the sewage in the second MABR treatment unit 3 meets the allowable influent C / N of the fourth MABR treatment unit 5, and then the valve body is opened to supply the sewage from the second MABR treatment unit 3 to the fourth MABR treatment unit 5.

[0068] Preferably, a corresponding valve body is provided on the pipeline connecting the membrane tank of the fourth MABR treatment unit 5 and the membrane tank of the third MABR treatment unit 4 to at least control the on-off of the flow between the membrane tank of the fourth MABR treatment unit 5 and the membrane tank of the third MABR treatment unit 4. The inlet end of the circulation channel of the fourth MABR treatment unit 5 is provided on the pipeline connecting the membrane tank of the fourth MABR treatment unit 5 and the membrane tank of the third MABR treatment unit 4, and is located upstream of the corresponding valve body on this pipeline along the flow direction of the sewage from the fourth MABR treatment unit 5 to the third MABR treatment unit 4, so that the membrane tank flow of the fourth MABR treatment unit 5 is adjustably connected to the corresponding circulation channel and the third MABR treatment unit 4. When the valve body on the pipeline connecting the membrane tank of the fourth MABR treatment unit 5 and the membrane tank of the third MABR treatment unit 4 is closed, the sewage circulates and is repeatedly treated in the membrane tank and the circulation channel of the fourth MABR treatment unit 5 until the C / N of the sewage in the fourth MABR treatment unit 5 meets the allowable influent C / N of the third MABR treatment unit 4, and then the valve body is opened to supply the sewage from the fourth MABR treatment unit 5 to the third MABR treatment unit 4.

[0069] The circulation channel enables each MABR treatment unit to have a stable circulation flow pattern, thereby ensuring the sewage treatment effect and sewage adaptability of the sewage treatment system.

[0070] Furthermore, the membrane tank flow of the first MABR treatment unit 2 is adjustably connected to the corresponding circulation channel and the third MABR treatment unit 4, and the membrane tank flow of the third MABR treatment unit 4 is adjustably connected to the corresponding circulation channel.

[0071] In some embodiments, the circulation channel is provided with an interface. The first MABR treatment unit 2, the second MABR treatment unit 3, the third MABR treatment unit 4, and the fourth MABR treatment unit 5 also each include an aeration pump and a gas-lift device. The aeration pump is connected to the air inlet of the corresponding MABR membrane module, the gas-lift device is connected to the air outlet of the corresponding MABR membrane module, and the gas-lift device is also connected to the interface of the corresponding circulation channel.

[0072] Specifically, the circulation channel is provided with an interface, and the interface is located between the inlet end and the outlet end of the circulation channel.

[0073] The first MABR treatment unit 2, the second MABR treatment unit 3, the third MABR treatment unit 4, and the fourth MABR treatment unit 5 also each include an aeration pump and a gas-lift device.

[0074] The aeration pump is connected to the air inlet of the MABR membrane module of the same MABR treatment unit, and is preferably provided with an opening and closing valve to supply air to the corresponding MABR membrane module. The air-lift device is connected between the air outlet of the MABR membrane module of the same MABR treatment unit and the interface of the circulation channel of the same MABR treatment unit, and is preferably provided with a regulating valve and a gas sampling port to use the air outlet of the MABR membrane module as the power to lift the sewage flow in the circulation channel, thereby improving the flow state effect of each MABR treatment unit.

[0075] Preferably, the flow velocity on the surface of the biofilm of each MABR treatment unit is about 45 m / h to 112 m / h.

[0076] Furthermore, the sewage treatment system is also provided with a gas supply device. The air inlet of the MABR membrane module or the air-lift device is connected to the gas supply device through a corresponding pipeline. When the gas supplied by the aeration pump to the MABR membrane module enters the air-lift device through the air outlet of the MABR membrane module and fails to fully meet the requirements of the air-lift device, the gas supply device supplies auxiliary air to the air-lift device through the MABR membrane module, or the gas supply device directly supplies auxiliary air to the air-lift device to meet the requirements of the air-lift device.

[0077] In some embodiments, pressure gauges, thermometers and flow meters are provided at both the air inlet and the air outlet of the MABR membrane module. The gas sampling port is connected to an oxygen mass concentration meter to obtain the gas flow rate and oxygen mass entering the MABR membrane module, and calculate the oxygen mass consumed by the MABR membrane module and the quantity of pollutants degraded by the MABR membrane module using oxygen as an electron acceptor.

[0078] In some embodiments, the first MABR treatment unit 2, the second MABR treatment unit 3, the third MABR treatment unit 4 and the fourth MABR treatment unit 5 also each include a membrane thickness and membrane metabolism control device. The membrane thickness and membrane metabolism control device is arranged in the MABR membrane module. The membrane thickness and membrane metabolism control device is preferably a membrane scrubbing device, and the MABR membrane module is scrubbed by the membrane scrubbing device to control the membrane thickness and membrane metabolism ability.

[0079] The membrane scrubbing device includes at least one of a gas scrubbing device, a water scrubbing device, a gas-water combined scrubbing device, a brush plate scrubbing device, a packing scrubbing device, and a particle medium friction scrubbing device.

[0080] By means of the membrane thickness and membrane metabolism control device, problems such as the decrease in mass transfer effect caused by the over-thick growth of the biofilm on the MABR membrane module and the imbalance between microbial anabolism and senescence are avoided, so as to ensure the treatment effect of the MABR membrane module.

[0081] It should be noted that the MABR treatment unit uses the corresponding MABR membrane module to treat the sewage in the membrane tank. The aeration pump supplies gas into the MABR membrane filaments of the MABR membrane module. Oxygen permeates through the MABR membrane filaments in the direction of the concentration gradient and enters the biofilm formed on the surface of the MABR membrane filaments, and the biofilm forms layers, including an aerobic layer close to the MABR membrane filaments, an anoxic-anaerobic layer far from the MABR membrane filaments, and an anoxic-aerobic layer located between the aerobic layer and the anoxic-anaerobic layer. The aerobic layer is enriched with autotrophic microorganisms such as nitrite bacteria and nitrifying bacteria to carry out nitrification reactions. The anoxic-aerobic layer is enriched with aerobic, anaerobic, and anoxic-aerobic bacteria to carry out simultaneous nitrification and denitrification reactions, shortcut nitrification and denitrification reactions, and anaerobic ammonium oxidation reactions, etc. The anoxic-anaerobic layer is enriched with denitrifying bacteria and a small part of hydrolytic acidifying bacteria. Therefore, the sewage undergoes various microbial reactions during the treatment process in the MABR treatment unit.

[0082] In some embodiments, the second MABR treatment unit 3 is used for simultaneous nitrification and denitrification reactions, the fourth MABR treatment unit 5 is used for autotrophic reactions, the third MABR treatment unit 4 is used for anaerobic ammonium oxidation reactions, and the first MABR treatment unit 2 is used for simultaneous nitrification and denitrification reactions and autotrophic reactions.

[0083] In other words, during the various microbial reactions in the second MABR treatment unit 3, the sewage mainly undergoes simultaneous nitrification and denitrification reactions to simultaneously remove dissolved organic carbon and nitrogen. During the various microbial reactions in the fourth MABR treatment unit 5, the sewage mainly undergoes autotrophic reactions to enable the cooperative work of ammonia-oxidizing bacteria and anaerobic ammonium-oxidizing bacteria. During the various microbial reactions in the third MABR treatment unit 4, the sewage mainly undergoes anaerobic ammonium oxidation reactions to still maintain excellent treatment capacity and treatment effect at a low pollutant concentration level. During the various microbial reactions in the first MABR treatment unit 2, the sewage mainly undergoes simultaneous nitrification and denitrification reactions and autotrophic reactions, and plays a role in resisting the impact load of water quality and water volume. Through the cooperation of the first MABR treatment unit 2, the second MABR treatment unit 3, the fourth MABR treatment unit 5, and the third MABR treatment unit 4, the sewage treatment system reacts efficiently and has a high treatment effect.

[0084] Preferably, the first MABR treatment unit 2, the second MABR treatment unit 3, the fourth MABR treatment unit 5, and the third MABR treatment unit 4 do not need to add external carbon sources during the treatment process, and can have high treatment effect and treatment efficiency, which plays a certain role in the carbon neutrality of the sewage treatment system.

[0085] In some embodiments, the allowable influent C / N of the second MABR treatment unit 3 ≥ the allowable influent C / N of the fourth MABR treatment unit 5 ≥ the allowable influent C / N of the third MABR treatment unit 4.

[0086] Specifically, there is no limit on the permitted influent C / N of the first MABR treatment unit 2. In other words, the permitted influent C / N of the first MABR treatment unit 2 can be any value.

[0087] The permitted influent C / N of the second MABR treatment unit 3, the fourth MABR treatment unit 5, and the third MABR treatment unit 4 decreases in sequence. The permitted influent C / N of the second MABR treatment unit 3 is preferably 1.5 - 3. The permitted influent C / N of the fourth MABR treatment unit 5 is preferably 0.63 - 1.5. The permitted influent C / N of the third MABR treatment unit 4 is preferably 0 - 0.63.

[0088] In some embodiments, the MABR membrane packing density of the fourth MABR treatment unit 5 ≥ the MABR membrane packing density of the third MABR treatment unit 4 ≥ the MABR membrane packing density of the second MABR treatment unit 3 ≥ the MABR membrane packing density of the first MABR treatment unit 2.

[0089] Specifically, the MABR membrane packing density of the first MABR treatment unit 2 is 150 m 2 / m 3 ~350 m 2 / m 3 , the MABR membrane packing density of the second MABR treatment unit 3 is 200 m 2 / m 3 ~400 m 2 / m 3 , the MABR membrane packing density of the fourth MABR treatment unit 5 is 350 m 2 / m 3 ~500 m 2 / m 3 , the MABR membrane packing density of the third MABR treatment unit 4 is 200 m 2 / m 3 ~450 m 2 / m 3 .

[0090] In some embodiments, the hydraulic retention time of the second MABR treatment unit 3 ≥ the hydraulic retention time of the fourth MABR treatment unit 5. The hydraulic retention time of the fourth MABR treatment unit 5 is greater than the hydraulic retention time of the first MABR treatment unit 2, and the hydraulic retention time of the fourth MABR treatment unit 5 is greater than the hydraulic retention time of the third MABR treatment unit 4.

[0091] Specifically, the total hydraulic retention time of the first MABR treatment unit 2, the second MABR treatment unit 3, the third MABR treatment unit 4, and the fourth MABR treatment unit 5 is 4 hours to 7 hours to ensure the treatment effect of the sewage treatment system.

[0092] The hydraulic retention time of the first MABR treatment unit 2 is 15% - 20% of the total hydraulic retention time, the hydraulic retention time of the second MABR treatment unit 3 is 35% - 40% of the total hydraulic retention time, the hydraulic retention time of the fourth MABR treatment unit 5 is 25% - 30% of the total hydraulic retention time, and the hydraulic retention time of the fourth MABR treatment unit 5 is 15% - 20% of the total hydraulic retention time.

[0093] In some embodiments, the biofilm thickness of the first MABR treatment unit 2 is 600 μm - 900 μm, the biofilm thickness of the second MABR treatment unit 3 is 650 μm - 900 μm, the biofilm thickness of the fourth MABR treatment unit 5 is 400 μm - 500 μm, and the biofilm thickness of the third MABR treatment unit 4 is 300 μm - 450 μm.

[0094] The biofilm thickness of each treatment unit is adjusted and controlled by the corresponding membrane thickness and membrane metabolism control device to maintain within the corresponding thickness range.

[0095] In some embodiments, the dissolved oxygen concentration of the first MABR treatment unit 2 is less than 0.3 mg / L, the dissolved oxygen concentration of the second MABR treatment unit 3 is less than 0.2 mg / L, the dissolved oxygen concentration of the fourth MABR treatment unit 5 is less than 0.1 mg / L, and the dissolved oxygen concentration of the third MABR treatment unit 4 is less than 0.1 mg / L.

[0096] By controlling at least one or all of the permitted influent C / N, MABR membrane packing density, hydraulic retention time, biofilm thickness, and dissolved oxygen concentration of each treatment unit, preferably controlling the permitted influent C / N, MABR membrane packing density, hydraulic retention time, and biofilm thickness, the sewage mainly undergoes simultaneous nitrification and denitrification reactions and autotrophic reactions in the first MABR treatment unit 2, mainly undergoes simultaneous nitrification and denitrification reactions in the second MABR treatment unit 3, mainly undergoes autotrophic reactions in the fourth MABR treatment unit 5, and mainly undergoes anaerobic ammonium oxidation reactions in the third MABR treatment unit 4.

[0097] Furthermore, the chemical oxygen demand (COD) removal rate of the first MABR treatment unit 2 is 85% - 95%, the ammonia nitrogen removal rate is 70% - 80%, and the total nitrogen removal rate is 70% - 80%. The COD removal rate of the second MABR treatment unit 3 is 55% - 80%, the ammonia nitrogen removal rate is 30% - 65%, and the total nitrogen removal rate is 40% - 65%. The COD removal rate of the fourth MABR treatment unit 5 is 60% - 75%, the ammonia nitrogen removal rate is 50% - 60%, and the total nitrogen removal rate is 50% - 60%. The COD removal rate of the third MABR treatment unit 4 is 20% - 30%, the ammonia nitrogen removal rate is 60% - 80%, and the total nitrogen removal rate is 50% - 80%. The overall influent COD removal rate of the first MABR treatment unit 2, the second MABR treatment unit 3, the fourth MABR treatment unit 5, and the third MABR treatment unit 4 is 90% - 95%, the influent total nitrogen removal rate is 85% - 90%, and the influent ammonia nitrogen removal rate is 90% - 95%, showing a high treatment effect.

[0098] In some embodiments, the sewage treatment system of the present invention further includes a carbon and phosphorus capture unit 6 and an extreme phosphorus capture unit 7. The outlet end of the carbon and phosphorus capture unit 6 is connected to the inlet end of the water inlet pipe 1, and the inlet end of the extreme phosphorus capture unit 7 is connected to the outlet end of the third MABR treatment unit 4.

[0099] As Figure 1 shown, the outlet end of the carbon and phosphorus capture unit 6 is connected to the inlet end of the water inlet pipe 1. Sewage first enters the carbon and phosphorus capture unit 6, and through flocculation, coagulation, and sedimentation, the organic matter, vegetable oil, and orthophosphate in the suspended solids and dissolved state are converted into sedimentary mud to remove carbon and phosphorus, and then the sewage is supplied to the water inlet pipe 1. The COD removal rate of the effluent of the carbon and phosphorus capture unit 6 is 45% - 75%, and the C / N of the effluent of the carbon and phosphorus capture unit 6 is less than 3.

[0100] The inlet end of the extreme phosphorus capture unit 7 is connected to the outlet end of the third MABR treatment unit 4. The effluent of the third MABR treatment unit 4 enters the extreme phosphorus capture unit 7, and the suspended substances such as biofilm fragments and the total phosphorus not used for cell synthesis metabolism in the effluent of the third MABR treatment unit 4 are removed through the extreme phosphorus capture unit 7, and the mud containing carbon and phosphorus is generated and discharged.

[0101] Thus, the treatment effect of the sewage treatment system is ensured, and the phosphorus removal rate of the sewage treatment system is greater than or equal to 99%.

[0102] Preferably, the carbon and phosphorus capture unit 6 includes a high-efficiency ion flotation device or a primary enhanced sedimentation tank with a surface load less than or equal to 0.6, so as to have a lower chemical dosage compared with chemical enhanced primary treatment, and at the same time reduce the difficulty of recovering chemicals in the sewage treatment system, enabling the sewage treatment system to also achieve carbon neutrality.

[0103] Preferably, the ultimate phosphorus capture unit 7 includes a shallow ion air flotation or an effective sedimentation tank.

[0104] In some embodiments, the sewage treatment system of the embodiments of the present invention further includes an anaerobic digestion sludge bed 8, a sludge hydrothermal hydrolysis unit 9, and a phosphorus recovery unit 10.

[0105] The anaerobic digestion sludge bed 8 is used to receive the sludge produced by the carbon and phosphorus capture unit 6. The anaerobic digestion sludge bed 8 is connected to the carbon and phosphorus capture unit 6 to supply the produced supernatant to the carbon and phosphorus capture unit 6. The sludge hydrothermal hydrolysis unit 9 is used to receive the sludge produced by the ultimate phosphorus capture unit 7 and the sludge produced by the anaerobic digestion sludge bed 8. The phosphorus recovery unit 10 is connected between the outlet end of the sludge hydrothermal hydrolysis unit 9 and the inlet end of the anaerobic digestion sludge bed 8.

[0106] As Figure 1 shown, the anaerobic digestion sludge bed 8 is connected to the carbon and phosphorus capture unit 6 through a corresponding sludge conveying device to receive the carbon and phosphorus-containing sludge produced by the carbon and phosphorus capture unit 6. The sludge reacts in the anaerobic digestion sludge bed 8 and produces supernatant, methane gas, and sludge. The anaerobic digestion sludge bed 8 is preferably an upflow anaerobic digestion sludge bed.

[0107] The sludge hydrothermal hydrolysis unit 9 is connected to the ultimate phosphorus capture unit 7 through a corresponding sludge conveying device to receive the carbon and phosphorus-containing sludge produced by the ultimate phosphorus capture unit 7. The sludge hydrothermal hydrolysis unit 9 is also connected to the anaerobic digestion sludge bed 8 through a sludge conveying device to receive the sludge produced by the anaerobic digestion sludge bed 8. The carbon and phosphorus-containing sludge supplied by the ultimate phosphorus capture unit 7 and the sludge supplied by the anaerobic digestion sludge bed 8 react in the sludge hydrothermal hydrolysis unit 9 and produce a mixture of phosphating solution and carbonizing solution, as well as surplus sludge.

[0108] The phosphorus recovery unit 10 is connected between the liquid outlet end of the sludge hydrothermal hydrolysis unit 9 and the liquid inlet end of the anaerobic digestion sludge bed 8 through a pipeline. The mixture of phosphating solution and carbonizing solution produced by the sludge hydrothermal hydrolysis unit 9 is fed into the phosphorus recovery unit 10 for reaction to obtain utilizable solid phosphorus and the remaining carbonizing solution. The remaining carbonizing solution is fed into the anaerobic digestion sludge bed 8 to react with the sludge supplied by the carbon and phosphorus capture unit 6.

[0109] By recovering utilizable solid phosphorus from the products of the carbon and phosphorus capture unit 6 and the ultimate phosphorus capture unit 7 through the anaerobic digestion sludge bed 8, the sludge hydrothermal hydrolysis unit 9, and the phosphorus recovery unit 10, on the one hand, the phosphorus content and the sludge discharge amount in the sludge finally discharged from the sewage treatment system are reduced, and the treatment effect is relatively high. On the other hand, the sewage treatment system can obtain solid phosphorus while treating sewage, playing a role in producing solid phosphorus, and further enabling the sewage treatment system to achieve carbon neutrality.

[0110] In some embodiments, the sewage treatment system of the embodiments of the present invention further includes a sludge dewatering unit 16. The sludge dewatering unit 16 is used to receive the sludge generated by the sludge hydrothermal hydrolysis unit 9.

[0111] As Figure 1 shown, the sludge hydrothermal hydrolysis unit 9 is connected to the sludge dewatering unit 16 through a corresponding sludge conveying device, so as to supply the surplus sludge generated by the sludge hydrothermal hydrolysis unit 9 to the sludge dewatering unit 16 for dehydration and harmless treatment, thereby ensuring the treatment effect of the sewage treatment system.

[0112] In some embodiments, the sewage treatment system of the embodiments of the present invention further includes a multi-stage grille unit 14. The outlet end of the multi-stage grille unit 14 is connected to the inlet end of the carbon and phosphorus capture unit 6, and the anaerobic digestion sludge bed 8 is connected to the multi-stage grille unit 14 to supply the supernatant generated to the multi-stage grille unit 14.

[0113] As Figure 1 shown, the multi-stage grille unit 14 is connected to the sewage supply pipeline and the liquid outlet end of the anaerobic digestion sludge bed 8. The sewage supply pipeline supplies sewage into the multi-stage grille unit 14, and the anaerobic digestion sludge bed 8 supplies the supernatant as sewage into the multi-stage grille unit 14. The sewage is first filtered by the multi-stage grille in the multi-stage grille unit 14, and then is fed into the carbon and phosphorus capture unit 6 through the pipeline connecting the outlet end of the multi-stage grille unit 14 and the inlet end of the carbon and phosphorus capture unit 6.

[0114] The multi-stage grille includes a plurality of grilles. Along the flowing direction of the sewage in the multi-stage grille unit 14, the plurality of grilles are arranged in multiple stages with gradually decreasing pore diameters. Preferably, the multi-stage grille includes a coarse grille, an inner diameter flow orifice plate fine grille, and an inner diameter flow membrane grille arranged in sequence. The inner diameter flow membrane grille is a non-metallic grille plate to intercept long fiber substances.

[0115] The treatment effect of the sewage treatment system is further ensured by the multi-stage grille unit 14, and the operation and treatment effect of other units downstream of the multi-stage grille unit 14 are prevented from being interfered by long fiber pollutants.

[0116] In some embodiments, the sewage treatment system of the embodiments of the present invention further includes a disinfection unit 15. The inlet end of the disinfection unit 15 is connected to the outlet end of the extreme phosphorus capture unit 7.

[0117] As Figure 1 shown, the outlet end of the extreme phosphorus capture unit 7 is connected to the inlet end of the disinfection unit 15 through a corresponding pipeline. The liquid discharged from the extreme phosphorus capture unit 7 enters the disinfection unit 15 and is disinfected in the disinfection unit 15 to remove pollutants such as pathogenic bacteria, and then is discharged by the disinfection unit 15. The effluent of the disinfection unit 15 is the drainage of the sewage treatment system and meets the sewage treatment requirements.

[0118] The disinfection unit 15 preferably adopts a combined disinfection method using ultraviolet light and sodium hypochlorite.

[0119] The treatment effect of the sewage treatment system is further ensured by the disinfection unit 15.

[0120] In some embodiments, the sewage treatment system of the embodiments of the present invention further includes a combined heat and power unit 11. The combined heat and power unit 11 is connected to the anaerobic digestion sludge bed 8 to receive methane generated by the anaerobic digestion sludge bed 8. The combined heat and power unit 11 is connected to the sludge hydrothermal hydrolysis unit 9 to supply heat to the sludge hydrothermal hydrolysis unit 9.

[0121] As Figure 1 shown, the gas outlet end of the anaerobic digestion sludge bed 8 is connected to the combined heat and power unit 11 through a corresponding pipeline to supply methane generated by the anaerobic digestion sludge bed 8 as an energy source into the combined heat and power unit 11. The combined heat and power unit 11 uses methane combustion to generate heat and electricity. The combined heat and power unit 11 is connected to the sludge hydrothermal hydrolysis unit 9 to supply the heat required for hydrothermal hydrolysis to the sludge hydrothermal hydrolysis unit 9. The combined heat and power unit 11 can also be connected to the electrical equipment in the plant where the sewage treatment system is set to supply electricity to the electrical equipment.

[0122] By utilizing the methane generated by the anaerobic digestion sludge bed 8 through the combined heat and power unit 11, on the one hand, it can avoid air pollution caused by direct methane emission. On the other hand, by generating heat and electricity from methane, it supplies the combined heat and power unit 11 and electrical equipment, reducing the energy consumption of the sewage treatment system and enabling the sewage treatment system to achieve carbon neutrality.

[0123] In some embodiments, the sewage treatment system of the embodiments of the present invention further includes a water source heat pump unit 12 and / or a hydroelectric power generation unit.

[0124] The water source heat pump unit 12 is used to obtain the temperature difference heat formed by the effluent of the disinfection unit 15. The water source heat pump unit 12 is connected to the combined heat and power unit 11 and / or the sludge hydrothermal hydrolysis unit 9 to supply heat to the combined heat and power unit 11 and / or the sludge hydrothermal hydrolysis unit 9. The hydroelectric power generation unit is used to obtain the potential energy formed by the effluent of the disinfection unit 15 and generate electricity.

[0125] As Figure 1 shown, the effluent of the disinfection unit 15 is discharged into the water area of the natural environment as the drainage of the sewage treatment system. There is a temperature difference between the temperature of the effluent of the disinfection unit 15 and the temperature of the water area of the natural environment. The water source heat pump unit 12 is preferably set at the position corresponding to the effluent end of the disinfection unit 15 in the natural environment water area to obtain the temperature difference heat formed by the temperature difference. The water source heat pump unit 12 is connected to the combined heat and power unit 11 and the sludge hydrothermal hydrolysis unit 9 to supply the temperature difference heat to the combined heat and power unit 11 and the sludge hydrothermal hydrolysis unit 9 for power generation of the combined heat and power unit 11 and hydrothermal hydrolysis of the sludge hydrothermal hydrolysis unit 9.

[0126] When there is a certain height difference between the water outlet end of the disinfection unit 15 and the water area of the natural environment, the water outlet of the disinfection unit 15 has a height potential energy. The hydroelectric power generation unit is preferably arranged at the water outlet end of the disinfection unit 15 to obtain the height potential energy of the water outlet of the disinfection unit 15 and generate electricity. The hydroelectric power generation unit is preferably connected to the electrical equipment of the plant where the sewage treatment system is set up to supply power to the electrical equipment.

[0127] Thus, the water source heat pump unit 12 and the hydroelectric power generation unit respectively utilize the temperature difference and height potential energy formed by the drainage of the sewage treatment system to generate heat and electricity, reduce the energy consumption of the sewage treatment system, and enable the sewage treatment system to achieve carbon neutrality.

[0128] It can be understood that the water source heat pump unit is not limited to being connected to the cogeneration unit and the sludge hydrothermal hydrolysis unit at the same time. In some other embodiments, the water source heat pump unit can be connected to one of the cogeneration unit and the sludge hydrothermal hydrolysis unit.

[0129] It can be understood that the sewage treatment system is not limited to being provided with the water source heat pump unit and the hydroelectric power generation unit at the same time. In some other embodiments, the sewage treatment system is provided with one of the water source heat pump unit and the hydroelectric power generation unit.

[0130] It can be understood that the water source heat pump unit and the hydroelectric power generation unit are not limited to being arranged opposite to the water outlet end of the disinfection unit. In some other embodiments, the sewage treatment system does not have a disinfection unit, and the water outlet of the extreme phosphorus capture unit is used as the drainage of the sewage treatment system. At this time, the water source heat pump unit is arranged opposite to the outlet end of the extreme phosphorus capture unit so that the water source heat pump unit can obtain the temperature difference heat formed by the water outlet of the extreme phosphorus capture unit, and the hydroelectric power generation unit is arranged at the outlet end of the extreme phosphorus capture unit so that the hydroelectric power generation unit can obtain the potential energy formed by the water outlet of the extreme phosphorus capture unit and generate electricity.

[0131] In some embodiments, the sewage treatment system of the embodiment of the present invention further includes a photovoltaic unit 13. The photovoltaic unit 13 is connected to the cogeneration unit 11 and / or the sludge hydrothermal hydrolysis unit 9 to supply heat to the cogeneration unit 11 and / or the sludge hydrothermal hydrolysis unit 9.

[0132] As Figure 1 shown, the photovoltaic unit 13 is used to absorb light heat and generate electricity. The photovoltaic unit 13 is connected to the cogeneration unit 11 and the sludge hydrothermal hydrolysis unit 9 to supply the absorbed heat to the cogeneration unit 11 and the sludge hydrothermal hydrolysis unit 9 for the cogeneration unit 11 to generate electricity and the sludge hydrothermal hydrolysis unit 9 to perform hydrothermal hydrolysis. The photovoltaic unit 13 is preferably also connected to the electrical equipment of the plant where the sewage treatment system is set up to supply power to the electrical equipment. By absorbing heat and generating electricity through the photovoltaic unit 13, the energy consumption of the sewage treatment system is reduced, and the sewage treatment system can achieve carbon neutrality.

[0133] In the description of the present invention, it should be understood that the terms "first", "second", etc. are only used for distinction and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0134] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0135] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0136] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0137] Although the above embodiments have been shown and described, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions, and variations made by those of ordinary skill in the art to the above embodiments are within the protection scope of the present invention.

Claims

1. A sewage treatment system, characterized in that: The invention comprises an inlet pipe (1), a first MABR treatment unit (2), a second MABR treatment unit (3), a third MABR treatment unit (4), a fourth MABR treatment unit (5) and a return pipe, wherein the first MABR treatment unit (2) and the second MABR treatment unit (3) are both connected between the inlet pipe (1) and the third MABR treatment unit (4), and the first MABR treatment unit (2) and the second MABR treatment unit (3) are arranged in parallel, and the flow rate of the inlet pipe (1) entering the first MABR treatment unit (2) and the flow rate of the second MABR treatment unit (3) The flow rate of the first MABR treatment unit (2) is adjustable, the return pipe is connected between the outlet end of the first MABR treatment unit (2) and the inlet end of the second MABR treatment unit (3), the flow rate of the first MABR treatment unit (2) entering the third MABR treatment unit (4) and the flow rate of the return pipe are adjustable, the fourth MABR treatment unit (5) is connected in series between the second MABR treatment unit (3) and the third MABR treatment unit (4), and the second MABR treatment unit (3) and the fourth MABR treatment unit (5) connected in series are both arranged in parallel with the first MABR treatment unit (2); The first MABR treatment unit (2) performs simultaneous nitrification and denitrification reaction and autotrophic reaction; the second MABR treatment unit (3) performs simultaneous nitrification and denitrification reaction; the third MABR treatment unit (4) performs anaerobic ammonia oxidation reaction; and the fourth MABR treatment unit (5) performs autotrophic reaction, so that ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria cooperate with each other.

2. The sewage treatment system according to claim 1, characterized in that: The second MABR treatment unit (3) and the fourth MABR treatment unit (5) connected in series are provided in a plurality of groups, and the plurality of groups of the second MABR treatment unit (3) and the fourth MABR treatment unit (5) connected in series are arranged in parallel; and / or The water inlet pipe (1) comprises a first branch (101) and a second branch (102) with adjustable flow rates, wherein the first branch (101) is connected to the first MABR treatment unit (2) and the second MABR treatment unit (3) in an adjustable flow rate, and the second branch (102) is connected to the first MABR treatment unit (2) and the fourth MABR treatment unit (5) in an adjustable flow rate.

3. The sewage treatment system according to claim 1, characterized in that: The first MABR treatment unit (2), the second MABR treatment unit (3), the third MABR treatment unit (4) and the fourth MABR treatment unit (5) all comprise a membrane pool, a MABR membrane assembly and a circulation channel, the MABR membrane assembly being arranged in the corresponding membrane pool, the circulation channel being connected between the outlet end and the inlet end of the corresponding membrane pool, the membrane pool flow of the second MABR treatment unit (3) being adjustably connected to the corresponding circulation channel and the fourth MABR treatment unit (5), and the membrane pool flow of the fourth MABR treatment unit (5) being adjustably connected to the corresponding circulation channel and the third MABR treatment unit (4).

4. The sewage treatment system according to claim 3, characterized in that: The circulation channel is provided with an interface, and the first MABR treatment unit (2), the second MABR treatment unit (3), the third MABR treatment unit (4) and the fourth MABR treatment unit (5) also include an aeration pump and an air stripping device, the aeration pump is connected to the air inlet of the corresponding MABR membrane assembly, the air stripping device is connected to the air outlet of the corresponding MABR membrane assembly, and the air stripping device is also connected to the corresponding interface of the circulation channel.

5. The sewage treatment system according to claim 1, characterized in that: The first MABR treatment unit (2), the second MABR treatment unit (3), the third MABR treatment unit (4) and the fourth MABR treatment unit (5) satisfy: The permitted inflow C / N of the second MABR treatment unit (3) ≥ the permitted inflow C / N of the fourth MABR treatment unit (5) ≥ the permitted inflow C / N of the third MABR treatment unit (4); The MABR membrane packing density of the fourth MABR treatment unit (5) is ≥ the MABR membrane packing density of the third MABR treatment unit (4) ≥ the MABR membrane packing density of the second MABR treatment unit (3) ≥ the MABR membrane packing density of the first MABR treatment unit (2); The hydraulic retention time of the second MABR treatment unit (3) is ≥ the hydraulic retention time of the fourth MABR treatment unit (5), the hydraulic retention time of the fourth MABR treatment unit (5) is greater than the hydraulic retention time of the first MABR treatment unit (2), and the hydraulic retention time of the fourth MABR treatment unit (5) is greater than the hydraulic retention time of the third MABR treatment unit (4); The biofilm thickness of the first MABR treatment unit (2) is 600 μm to 900 μm, the biofilm thickness of the second MABR treatment unit (3) is 650 μm to 900 μm, the biofilm thickness of the fourth MABR treatment unit (5) is 400 μm to 500 μm, and the biofilm thickness of the third MABR treatment unit (4) is 300 μm to 450 μm; The dissolved oxygen concentration of the first MABR treatment unit (2) is less than 0.3 mg / L, the dissolved oxygen concentration of the second MABR treatment unit (3) is less than 0.2 mg / L, the dissolved oxygen concentration of the fourth MABR treatment unit (5) is less than 0.1 mg / L, and the dissolved oxygen concentration of the third MABR treatment unit (4) is less than 0.1 mg / L; At least one of .

6. The sewage treatment system according to any one of claims 1 to 5, characterized in that: It also comprises a carbon-phosphorus capture unit (6) and a limit phosphorus capture unit (7), wherein the outlet end of the carbon-phosphorus capture unit (6) is connected to the inlet end of the water inlet pipe (1), and the inlet end of the limit phosphorus capture unit (7) is connected to the outlet end of the third MABR treatment unit (4).

7. The sewage treatment system according to claim 6, characterized in that: Also includes: An anaerobic digestion sludge bed (8), the anaerobic digestion sludge bed (8) receiving the mud produced by the carbon and phosphorus capture unit (6), the anaerobic digestion sludge bed (8) being connected to the carbon and phosphorus capture unit (6) so as to supply the produced supernatant to the carbon and phosphorus capture unit (6); A sludge thermal hydrolysis unit (9), wherein the sludge thermal hydrolysis unit (9) receives the mud produced by the limit phosphorus capture unit (7) and the sludge produced by the anaerobic digestion sludge bed (8); A phosphorus recovery unit (10) is connected between the outlet end of the sludge thermal hydrolysis unit (9) and the inlet end of the anaerobic digestion sludge bed (8).

8. The sewage treatment system according to claim 7, characterized in that: Also includes at least one of a cogeneration unit (11), a water source heat pump unit (12), a hydroelectric unit and a photovoltaic unit (13); The cogeneration unit (11) is connected to the anaerobic digestion sludge bed (8) to receive methane generated by the anaerobic digestion sludge bed (8), and the cogeneration unit (11) is connected to the sludge thermal hydrolysis unit (9) to supply heat to the sludge thermal hydrolysis unit (9); The water source heat pump unit (12) obtains the temperature difference heat formed by the outlet water of the limit phosphorus capture unit (7), and the water source heat pump unit (12) is connected to the cogeneration unit (11) and / or the sludge thermal hydrolysis unit (9) to supply heat to the cogeneration unit (11) and / or the sludge thermal hydrolysis unit (9); The hydroelectric power generation unit obtains the potential energy generated by the outlet water of the extreme phosphorus capture unit (7) and generates electricity; The photovoltaic unit (13) is connected to the cogeneration unit (11) and / or the sludge thermal hydrolysis unit (9) to supply heat to the cogeneration unit (11) and / or the sludge thermal hydrolysis unit (9).

9. The sewage treatment system according to claim 8, characterized in that: It also includes at least one of a multi-stage grid unit (14), a disinfection unit (15) and a sludge dewatering unit (16); The outlet end of the multi-stage grid unit (14) is connected to the inlet end of the carbon-phosphorus capture unit (6), and the anaerobic digestion sludge bed (8) is connected to the multi-stage grid unit (14) to supply the generated supernatant to the multi-stage grid unit (14); The inlet end of the disinfection unit (15) is connected to the outlet end of the limit phosphorus capture unit (7), the water source heat pump unit (12) obtains the temperature difference heat generated by the outlet water of the disinfection unit (15), and the hydroelectric power generation unit obtains the potential energy generated by the outlet water of the disinfection unit (15) and generates electricity; The sludge dehydration unit (16) receives the sludge generated by the sludge thermal hydrolysis unit (9).

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