A land-saving low-carbon sewage treatment system

Abstract

The present application provides a land-saving low-carbon sewage treatment system, which relates to the technical field of sewage treatment. The system of the present application includes a biochemical treatment system composed of an anaerobic tank, an anoxic tank, an aerobic tank and an MBR tank connected in sequence, and a deoxygenation tank and a hydrocyclone separation device are connected in sequence after the MBR tank; it also includes: a monitoring component, which is used to collect the flow and water quality parameters of the inlet and outlet water of the biochemical treatment system, the sludge parameters in the aerobic tank and the deoxygenation tank, and the sludge parameters of the residual sludge discharged from the MBR tank; a processing component, which is used to receive and analyze the collected data of the monitoring component and generate adjustment instructions; a control component, which is used to act according to the adjustment instructions to realize the single-stage internal and external reflow control of mixed sludge and high-density sludge. The technical solution of the present application can effectively reduce the high energy consumption caused by the existing multi-stage sludge return on the basis of achieving land saving.

Description

Technical Field

[0001] The present application belongs to the technical field of sewage treatment, and specifically relates to a land-saving low-carbon sewage treatment system. Background Art

[0002] The sewage treatment industry is one of the top ten greenhouse gas emission industries in the world. Its carbon emissions account for 2% to 3% of the total global carbon emissions, and are still increasing year by year. Carbon emissions from sewage treatment systems mainly come from greenhouse gases such as nitrous oxide, carbon dioxide, and methane produced by biochemical reactions, as well as electricity consumption and chemical consumption; and in order to meet increasingly stringent effluent quality standards, the electricity consumption and chemical consumption of sewage treatment processes are both on the rise. At the same time, due to the scarcity of land resources and the need for upgrading and transformation, sewage treatment plants often face the problem of insufficient land.

[0003] Among the related technologies, MBR (Membrane Bioreactor) technology has been widely used. It can achieve efficient solid-liquid separation. Compared with the secondary sedimentation tank, it occupies a smaller area and can effectively reduce and save land resources. In addition, the high-throughput MBR can further reduce the floor space while treating the same amount of water. In the process of realizing the present invention, the applicant found that the existing MBR application adopts a multi-stage sludge return method, which increases the operating energy consumption.

[0004] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] In order to overcome the problems existing in the related art to at least a certain extent, the embodiment of the present application provides a land-saving low-carbon sewage treatment system. On the basis of applying MBR, by improving the sludge return implementation method, the purpose of saving land and taking into account low-carbon emissions is achieved in the implementation of the sewage treatment system.

[0006] The present application provides a land-saving low-carbon sewage treatment system, which includes a biochemical treatment system consisting of an anaerobic tank, an anoxic tank, an aerobic tank and an MBR tank connected in sequence, wherein the MBR tank is connected in sequence to a deoxygenation tank and a hydrocyclone separation device; and further includes:

[0007] Monitoring components, which are used to collect,

[0008] The flow rate and water quality parameters of the inlet and outlet water of the biochemical treatment system, the sludge parameters in the aerobic tank and the deoxygenation tank, the sludge parameters of the excess sludge discharged from the MBR tank, the flow parameters of the mixed sludge returned from inside and outside the deoxygenation tank to the biochemical treatment system, the flow parameters of the high-density sludge returned from inside and outside the hydrocyclone separation device to the biochemical treatment system, and the sludge parameters of the excess light sludge discharged from the upper end of the hydrocyclone separation device;

[0009] A processing component, which is used to receive and analyze the collected data of the monitoring component and generate adjustment instructions;

[0010] The regulating component is used to act according to the adjustment instruction to realize single-stage internal and external reflow control of mixed sludge and high-density sludge.

[0011] In a possible implementation, the monitoring component includes an inlet flow meter, an inlet BOD analyzer, an inlet suspended solids analyzer, an inlet TN analyzer, an outlet NO3-N analyzer, and an aerobic tank MLSS analyzer arranged at the aerobic tank, which are arranged on the inlet and outlet process pipelines of the biochemical treatment system;

[0012] A mixed sludge internal return pipeline is arranged between the deoxygenation tank and the anoxic tank, the regulating component comprises a mixed sludge internal return pump and a mixed sludge internal return valve arranged on the mixed sludge internal return pipeline, and the monitoring component further comprises a mixed sludge internal return flow meter arranged on the mixed sludge internal return pipeline;

[0013] A mixed sludge external return pipeline is arranged between the deoxygenation tank and the anaerobic tank, the regulating component further comprises a mixed sludge external return pump and a mixed sludge external return valve arranged on the mixed sludge external return pipeline, and the monitoring component further comprises a mixed sludge external return flow meter arranged on the mixed sludge external return pipeline;

[0014] The monitoring component also includes a residual sludge MLSS analyzer and a residual sludge discharge flowmeter arranged on the residual sludge discharge pipeline, and the regulating component also includes a residual sludge discharge pump and a residual sludge discharge valve arranged on the residual sludge discharge pipeline;

[0015] The control component also includes a deoxygenation tank mud inlet valve arranged on the mud inlet pipeline connecting the deoxygenation tank to the MBR tank, and the monitoring component also includes a deoxygenation tank sludge MLSS analyzer and a deoxygenation tank sludge interface meter arranged at the deoxygenation tank;

[0016] The control component also includes a deoxygenated sludge pump and a hydrocyclone mud inlet valve arranged on the mud inlet pipeline connecting the hydrocyclone separator to the deoxygenation tank, and the monitoring component also includes a high-density sludge MLSS analyzer arranged at the high-density sludge discharge outlet at the bottom of the hydrocyclone separator;

[0017] A high-density sludge internal return pipeline is arranged between the hydrocyclone separation device and the anoxic tank, the regulating component further comprises a high-density sludge internal return pump and a high-density sludge internal return valve arranged on the high-density sludge internal return pipeline, and the monitoring component further comprises a high-density sludge internal return flow meter arranged on the high-density sludge internal return pipeline;

[0018] A high-density sludge external return pipeline is also provided between the hydrocyclone separation device and the anaerobic tank, the regulating component further includes a high-density sludge external return pump and a high-density sludge external return valve provided on the high-density sludge external return pipeline, and the monitoring component further includes a high-density sludge external return flow meter provided on the high-density sludge external return pipeline;

[0019] The monitoring component also includes a light sludge MLSS analyzer and a residual light sludge discharge flowmeter arranged on the light residual sludge discharge pipeline of the hydrocyclone separation device, and the regulating component also includes a residual light sludge discharge pump and a residual light sludge discharge valve arranged on the light residual sludge discharge pipeline.

[0020] In a possible implementation, a MABR tank is further provided in the biochemical treatment device between the anoxic tank and the aerobic tank.

[0021] In a possible implementation, the process of receiving and analyzing the collected data of the monitoring component and generating the adjustment instruction includes:

[0022] Based on the monitoring data of the deoxygenation tank sludge MLSS analyzer and the deoxygenation tank sludge interface meter, the SVI value of the deoxygenation tank sludge is calculated and determined;

[0023] According to the threshold range of the sludge SVI value, an adjustment instruction is generated to implement a corresponding control process operation;

[0024] Wherein, when the sludge SVI value is less than or equal to the first threshold value, the generated adjustment instruction implements the following first process control operation: the sludge in the MBR tank first enters the deoxygenation tank for oxygen removal, and then directly returns from the deoxygenation tank to the anoxic tank through the mixed sludge internal return pipeline, and returns to the anaerobic tank through the mixed sludge external return pipeline, and the remaining sludge is discharged through the remaining sludge discharge pipeline;

[0025] When the sludge SVI value is greater than the first threshold value and less than or equal to the second threshold value, the generated adjustment instruction implements the following second process control operation: the sludge in the MBR tank first enters the deoxygenation tank for deoxygenation, and then part of the sludge is returned from the deoxygenation tank to the anoxic tank through the mixed sludge internal return pipeline, and is returned to the anaerobic tank through the mixed sludge external return pipeline, and the other part of the sludge enters the hydrocyclone separation device from the deoxygenation tank for treatment, and then returns to the anoxic tank through the high-density sludge internal return pipeline, and is returned to the anaerobic tank through the high-density sludge external return pipeline, and the remaining sludge is discharged together through the remaining sludge discharge pipeline and the light remaining sludge discharge pipeline;

[0026] When the sludge SVI value is greater than the second threshold value, the generated adjustment instruction implements the following third process control operation: the sludge in the MBR pool first enters the deoxygenation tank for oxygen removal, and then all the sludge enters the hydrocyclone separation device from the deoxygenation tank for treatment, and then returns to the anoxic tank through the high-density sludge internal return pipeline, and returns to the anaerobic tank through the high-density sludge external return pipeline, and the remaining sludge is discharged through the light remaining sludge discharge pipeline.

[0027] In a possible implementation, during the implementation of the first process control operation, the amount of sludge internal and external reflow and the amount of excess sludge discharged are controlled based on the following expression:

[0028]

[0029]

[0030]

[0031] in,

[0032] represents the return flow rate in the mixed sludge, Indicates the real-time flow rate of water inlet, unit: m 3 / d,

[0033] Indicates the real-time TN concentration of the influent water. Indicates the TN target value of the outlet water, in mg / L.

[0034] Indicates the mixed sludge external return flow rate, unit: m 3 / d,

[0035] Indicates the MLSS concentration of aerobic tank sludge, Indicates the MLSS concentration of deoxygenation tank sludge, in mg / L.

[0036] Indicates the amount of residual sludge discharged, in kg / d;

[0037] It represents the sludge yield coefficient, unit is kgVSS / kgBOD5;

[0038] Indicates the real-time BOD concentration of the influent. Indicates the target value of effluent BOD, in mg / L;

[0039] Indicates the conversion rate between SS and MLSS, unit: gMLSS / gSS,

[0040] Indicates the real-time SS concentration of the influent water. Indicates the outlet SS target value, in mg / L.

[0041] Indicates the sludge attenuation coefficient, unit d -1 ,

[0042] V represents the total volume of the biochemical system, in m 3 ,

[0043] It indicates the residual sludge concentration of mixed sludge, in mg / L.

[0044] In a possible implementation, during the implementation of the second process control operation, the sludge internal and external reflow amounts and the residual sludge discharge amount are controlled based on the following expressions:

[0045]

[0046]

[0047]

[0048] in,

[0049] represents the total sludge return flow, Indicates the high-density sludge external return flow rate, unit: m 3 / d,

[0050] Indicates the concentration of high-density sludge, in mg / L.

[0051] A represents the external reflow coefficient of mixed sludge, B represents the external reflow coefficient of high-density sludge,

[0052] represents the total internal sludge recycle volume, Indicates the reflow rate of high-density sludge, unit: m 3 / d,

[0053] C represents the internal recirculation coefficient of mixed sludge, D represents the internal recirculation coefficient of high-density sludge,

[0054] represents the total amount of sludge discharged, Indicates the discharge of light sludge, in kg / d;

[0055] Indicates light sludge concentration, unit: mg / L.

[0056] E represents the mixed sludge discharge coefficient, and F represents the light sludge discharge coefficient.

[0057] In a possible implementation, during the implementation of the third process control operation, the amount of sludge internal and external reflow and the amount of excess sludge discharged are controlled based on the following expression:

[0058]

[0059]

[0060]

[0061]

[0062] in,

[0063] SV represents the sludge settling ratio of the deoxygenation tank, unit: %

[0064] represents the volume of the hypoxic pool, Indicates the volume of the MABR tank, in m 3 ,

[0065] It indicates the denitrification rate, in units of kgNO3-N / (kgMLSS·d),

[0066] Indicates the outlet water NO3-N concentration in mg / L.

[0067] In a possible implementation, each pump device in the control component adopts a variable frequency pump.

[0068] In a possible implementation, the membrane flux range of the membrane assembly used in the MBR pool is 30 to 40LMH.

[0069] In a possible implementation, the processing component is implemented based on a PLC controller.

[0070] The land-saving low-carbon sewage treatment system provided in the embodiment of the present application includes a biochemical treatment system composed of an anaerobic tank, an anoxic tank, an aerobic tank and an MBR tank connected in sequence, and a deoxygenation tank and a hydrocyclone separation device are connected in sequence after the MBR tank; it also includes: a monitoring component, which is used to collect the flow rate and water quality parameters of the inlet and outlet water of the biochemical treatment system, the sludge parameters in the aerobic tank and the deoxygenation tank, the sludge parameters of the residual sludge discharged from the MBR tank, the mixed sludge flow parameters of the mixed sludge returned from the inside and outside of the deoxygenation tank to the biochemical treatment system, the high-density sludge flow parameters of the hydrocyclone separation device returned to the biochemical treatment system, and the sludge parameters of the residual light sludge discharged from the upper end of the hydrocyclone separation device; a processing component, which is used to receive and analyze the collected data of the monitoring component and generate an adjustment instruction; a control component, which is used to act according to the adjustment instruction to realize the single-stage internal and external reflow control of the mixed sludge and the high-density sludge.

[0071] In the technical solution of the present application, MBR is used instead of the secondary sedimentation tank, which effectively reduces the floor space of the mud-water separation zone; on this basis, a deoxygenation tank is arranged after the MBR, and an internal reflux pipeline of the sludge is arranged at the end of the deoxygenation tank to the anoxic tank to realize single-stage sludge reflux. Compared with the multi-stage internal reflux from MBR to aerobic tank, aerobic tank to anoxic tank, and anoxic tank to anaerobic tank in the existing method, the high energy consumption caused by the existing multi-stage sludge reflux can be effectively reduced based on the reduction of the reflux times and the number of reflux pumps.

[0072] Other advantages, objectives, and features of the present application will be described in part in the following description, and in part will be apparent to those skilled in the art based on the following examination and study, or may be taught from the practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The accompanying drawings are used to provide a further understanding of the technical solution of the present application or the prior art, and constitute a part of the specification. Among them, the accompanying drawings expressing the embodiments of the present application are used together with the embodiments of the present application to explain the technical solution of the present application, but do not constitute a limitation on the technical solution of the present application.

[0074] Figure 1 A schematic diagram of the system structure of a land-saving low-carbon sewage treatment system provided in one embodiment of the present application;

[0075] Figure 2 A schematic diagram of the system structure of a land-saving low-carbon sewage treatment system provided in another embodiment of the present application;

[0076] Figure 3 A schematic diagram illustrating the control logic of a land-saving, low-carbon sewage treatment system provided in one embodiment of the present application.

[0077] In the figure,

[0078] 1- inlet and outlet process pipelines; 101- inlet flowmeter; 102- inlet BOD analyzer; 103- inlet suspended solids analyzer; 104- inlet TN analyzer; 105- aerobic pool MLSS analyzer; 106- outlet NO3-N analyzer;

[0079] 2-mixed sludge internal reflux pipeline; 201-mixed sludge internal reflux pump; 202-mixed sludge internal reflux valve; 203-mixed sludge internal reflux flowmeter;

[0080] 3-mixed sludge external return pipeline; 301-mixed sludge external return pump; 302-mixed sludge external return valve; 303-mixed sludge external return flow meter;

[0081] 4-residual sludge discharge pipeline; 401-residual sludge MLSS analyzer; 402-residual sludge discharge pump; 403-residual sludge discharge valve; 404-residual sludge discharge flow meter;

[0082] 5a-the first mud inlet pipeline; 5a1-the mud inlet valve of the deoxygenation tank; 5a2-the MLSS analyzer of the sludge in the deoxygenation tank; 5a3-the sludge interface meter of the deoxygenation tank;

[0083] 5b-second sludge inlet pipeline; 5b1-deoxygenated sludge pump; 5b2-hydrocyclone separator sludge inlet valve; 5b3-high-density sludge MLSS analyzer;

[0084] 6-high-density sludge internal return pipeline; 601-high-density sludge internal return pump; 602-high-density sludge internal return valve; 603-high-density sludge internal return flow meter;

[0085] 7-high-density sludge external return pipeline; 701-high-density sludge external return pump; 702-high-density sludge external return valve; 703-high-density sludge external return flow meter;

[0086] 8-light residual sludge discharge pipeline; 801-light sludge MLSS analyzer; 802-residual light sludge discharge flowmeter; 803-residual light sludge discharge pump; 804-residual light sludge discharge valve. DETAILED DESCRIPTION

[0087] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other implementation methods obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0088] As described in the background technology, in the related technology, MBR (Membrane Bioreactor) technology has been widely used. It can achieve efficient solid-liquid separation. Compared with the secondary sedimentation tank, it occupies a smaller area and can effectively reduce and save land resources. High-throughput MBR can further reduce the floor space while treating the same amount of water. In the process of realizing the present invention, the applicant found that the existing MBR application adopts a multi-stage sludge return method, which increases the operating energy consumption.

[0089] In view of this, the present application proposes a land-saving low-carbon sewage treatment system, which, based on the application of MBR, improves the implementation method of sludge return to achieve the purpose of saving land and taking low carbon emissions into account in the implementation of the sewage treatment system.

[0090] In one embodiment, if Figure 1 As shown, the land-saving low-carbon sewage treatment system proposed in the present application includes a biochemical treatment system consisting of an anaerobic tank, an anoxic tank, an aerobic tank and an MBR tank connected in sequence, and a deoxygenation tank and a hydrocyclone separation device are connected in sequence after the MBR tank; and also includes:

[0091] Monitoring components, which are used to collect,

[0092] The flow rate and water quality parameters of the inlet and outlet water of the biochemical treatment system, the sludge parameters in the aerobic tank and the deoxygenation tank, the sludge parameters of the excess sludge discharged from the MBR tank, the flow parameters of the mixed sludge returned from inside and outside the deoxygenation tank to the biochemical treatment system, the flow parameters of the high-density sludge returned from inside and outside the hydrocyclone separation device to the biochemical treatment system, and the sludge parameters of the excess light sludge discharged from the upper end of the hydrocyclone separation device;

[0093] A processing component, which is used to receive and analyze the collected data of the monitoring component and generate adjustment instructions;

[0094] The regulating component is used to act according to the adjustment instruction to realize the single-stage internal and external reflow control of mixed sludge and high-density sludge.

[0095] It is easy for those skilled in the art to understand that the above-mentioned monitoring component can be implemented based on relevant instruments and meters set in the system, and the control component can be implemented based on relevant valves and pump equipment;

[0096] For example, Figure 1As shown, as a specific implementation, in this embodiment, the monitoring component includes an inlet flow meter 101, an inlet BOD (biochemical oxygen demand) analyzer 102, an inlet suspended solids analyzer 103, an inlet TN (total nitrogen) analyzer 104, an outlet NO3-N (nitrate nitrogen) analyzer 106, and an aerobic tank MLSS (sludge concentration) analyzer 105 arranged at the aerobic tank, which are arranged on the inlet and outlet water process pipelines 1 of the biochemical treatment system;

[0097] A mixed sludge internal return pipeline 2 is provided between the deoxygenation tank and the anoxic tank, the regulating component includes a mixed sludge internal return pump 201 and a mixed sludge internal return valve 202 provided on the mixed sludge internal return pipeline 2, and the monitoring component also includes a mixed sludge internal return flow meter 203 provided on the mixed sludge internal return pipeline 2;

[0098] A mixed sludge external return pipeline 3 is provided between the deoxygenation tank and the anaerobic tank, the regulating component further includes a mixed sludge external return pump 301 and a mixed sludge external return valve 302 provided on the mixed sludge external return pipeline 3, and the monitoring component further includes a mixed sludge external return flow meter 303 provided on the mixed sludge external return pipeline 3;

[0099] Similar to the prior art, a residual sludge discharge pipeline 4 is provided at the MBR tank, the monitoring component further includes a residual sludge MLSS analyzer 401 and a residual sludge discharge flowmeter 404 provided on the residual sludge discharge pipeline 4, and the regulating component further includes a residual sludge discharge pump 402 and a residual sludge discharge valve 403 provided on the residual sludge discharge pipeline 4;

[0100] The control component also includes a deoxygenation tank mud inlet valve 5a1 arranged on the first mud inlet pipeline 5a connecting the deoxygenation tank to the MBR tank, and the monitoring component also includes a deoxygenation tank sludge MLSS analyzer 5a2 and a deoxygenation tank sludge interface meter 5a3 arranged at the deoxygenation tank;

[0101] The control component also includes a deoxygenated sludge pump 5b1 and a hydrocyclone mud inlet valve 5b2 provided on the second mud inlet pipeline 5b of the hydrocyclone separator connected to the deoxygenation tank, and the monitoring component also includes a high-density sludge MLSS analyzer 5b3 provided at the high-density sludge outlet at the bottom of the hydrocyclone separator;

[0102] A high-density sludge internal return pipeline 6 is provided between the hydrocyclone separation device and the anoxic tank, the control component further includes a high-density sludge internal return pump 601 and a high-density sludge internal return valve 602 provided on the high-density sludge internal return pipeline 6, and the monitoring component further includes a high-density sludge internal return flow meter 603 provided on the high-density sludge internal return pipeline 6;

[0103] A high-density sludge external return pipeline 7 is also provided between the hydrocyclone separation device and the anaerobic tank, the control component further includes a high-density sludge external return pump 701 and a high-density sludge external return valve 702 provided on the high-density sludge external return pipeline 7, and the monitoring component further includes a high-density sludge external return flow meter 703 provided on the high-density sludge external return pipeline 7;

[0104] like Figure 1 As shown, the monitoring component also includes a light sludge MLSS analyzer 801 and a residual light sludge discharge flowmeter 802 arranged on the light residual sludge discharge pipeline 8 of the hydrocyclone separation device, and the control component also includes a residual light sludge discharge pump 803 and a residual light sludge discharge valve 804 arranged on the light residual sludge discharge pipeline 8.

[0105] As a specific implementation method, each pump device in the above-mentioned control component adopts a variable frequency pump, that is, the pump is regulated by a frequency converter equipped with the variable frequency pump, which is conducive to achieving more complex control and can further reduce the overall power consumption of the system.

[0106] On this basis, in this embodiment, the processing component is implemented based on a PLC controller, and the monitoring component and the control component of the above-mentioned form and configuration are electrically connected to the PLC controller. In practice, the single-stage internal and external reflow control of mixed sludge and high-density sludge is realized based on relevant control methods.

[0107] In the technical solution of the present application, MBR is used instead of the secondary sedimentation tank, which effectively reduces the floor space of the mud-water separation zone; on this basis, a deoxygenation tank is arranged after the MBR, and an internal reflux pipeline of the sludge is arranged at the end of the deoxygenation tank to the anoxic tank to realize single-stage sludge reflux. Compared with the multi-stage internal reflux from MBR to aerobic tank, aerobic tank to anoxic tank, and anoxic tank to anaerobic tank in the existing method, the high energy consumption caused by the existing multi-stage sludge reflux can be effectively reduced based on the reduction of the reflux times and the number of reflux pumps.

[0108] Furthermore, based on the above-mentioned embodiments, the MBR pool may adopt a high-flux membrane component to further reduce the space occupied by the system. For example, in some embodiments, the membrane flux range of the membrane component used in the MBR pool is 30 to 40LMH, which means that the number of liters of liquid passing through per square meter per hour is 30 to 40.

[0109] Based on the above embodiments, in some embodiments, in order to further reduce the footprint and energy consumption of the system, Figure 2 As shown, a MABR tank (Membrane Aerated Biofilm Reactor) is also arranged between the anoxic tank and the aerobic tank in the biochemical treatment device, that is, in this embodiment, "anaerobic tank-anoxic tank-MABR tank-aerobic tank-MBR tank" is used as the biochemical treatment system.

[0110] MABR technology uses a bubble-free aeration method. Compared with the activated sludge method, MABR couples activated sludge and biofilm, which can simultaneously improve aeration efficiency and denitrification effect, thereby reducing operating energy consumption and process floor space, and also reducing nitrous oxide greenhouse gas emissions; however, when external conditions change dramatically, activated sludge will still have problems such as poor settling performance, and sludge swelling will lead to an increase in sludge treatment operating energy consumption and drug consumption;

[0111] To this end, in this embodiment, based on Figure 2 The system structure shown in this application has been specifically configured in terms of the method for achieving sludge return.

[0112] Specifically, in this embodiment, the process of the processing component receiving and analyzing the collected data of the monitoring component and generating the adjustment instruction includes:

[0113] Based on the monitoring data of the deoxygenation tank sludge MLSS analyzer 5a2 and the deoxygenation tank sludge interface meter 5a3, the SVI value of the deoxygenation tank sludge is calculated and determined. It is easy for those skilled in the art to understand that the SVI (sludge volume index) here can be detected and calculated through parameters such as sludge concentration MLSS after the sludge has settled for 30 minutes; similarly, SV (sludge settling ratio) refers to the volume ratio (%) of the precipitated sludge to the mixed liquor taken after the sludge has settled for 30 minutes. When the SVI value is obtained, the SV value can also be obtained;

[0114] Afterwards, according to the threshold range of the sludge SVI value, an adjustment instruction is generated to implement the corresponding control process operation;

[0115] like Figure 3 As shown, when the sludge SVI value is less than or equal to the first threshold value (such as in this embodiment, the first threshold value is Figure 3 60 shown in , unit mL / g), the generated adjustment instruction implements the following first process control operation:

[0116] The sludge in the MBR tank first enters the deoxygenation tank for oxygen removal, and then directly flows back from the deoxygenation tank to the anoxic tank through the mixed sludge internal return pipeline 2, that is, the nitrification liquid is refluxed, and the mixed sludge is externally returned to the anaerobic tank through the mixed sludge external return pipeline 3, and the remaining sludge is discharged through the remaining sludge discharge pipeline 4;

[0117] In actual implementation, combined with Figure 2The system configuration shown uses an inlet flow meter, an inlet TN analyzer, an aerobic zone sludge MLSS analyzer, a deoxygenation zone sludge MLSS analyzer and a sludge interface meter, a mixed sludge internal return flow meter, and a mixed sludge external return flow meter to jointly control the internal and external return flows of the sludge; an inlet flow meter, an inlet BOD analyzer, an inlet suspended solids analyzer, and a residual sludge MLSS analyzer to jointly control the residual sludge discharge; specifically, during the implementation of the first process control operation, the internal and external return flows of the sludge and the residual sludge discharge are controlled based on the following expressions:

[0118] (1)

[0119] (2)

[0120] (3)

[0121] In expressions (1) to (3),

[0122] represents the return flow rate in the mixed sludge, Indicates the real-time flow rate of water inlet, unit: m 3 / d,

[0123] Indicates the real-time TN concentration of the influent water. Indicates the TN target value of the outlet water, in mg / L.

[0124] Indicates the mixed sludge external return flow rate, unit: m 3 / d,

[0125] Indicates the MLSS concentration of aerobic tank sludge, Indicates the MLSS concentration of deoxygenation tank sludge, in mg / L.

[0126] Indicates the amount of residual sludge discharged, in kg / d;

[0127] It represents the sludge yield coefficient, unit is kgVSS / kgBOD5;

[0128] Indicates the real-time BOD concentration of the influent. Indicates the target value of effluent BOD, in mg / L;

[0129] Indicates the conversion rate between SS and MLSS, unit: gMLSS / gSS,

[0130] Indicates the real-time SS concentration of the influent water. Indicates the outlet SS target value, in mg / L.

[0131] Indicates the sludge attenuation coefficient, unit d -1 , is a constant and can be selected according to the relevant technical manual.

[0132] V represents the total volume of the biochemical system, in m 3 ,

[0133] It indicates the residual sludge concentration of mixed sludge, in mg / L, based on the detection by MLSS analyzer.

[0134] It should also be noted that in the first process control operation, the internal reflow ratio of the mixed sludge is generally controlled between 100% and 400%, and the external reflow ratio of the mixed sludge is generally controlled between 50% and 100%. At the same time, the internal and external reflow amounts are adjusted based on feedback from the SVI real-time data.

[0135] like Figure 3 As shown, when the sludge SVI value is greater than the first threshold value and less than or equal to the second threshold value (for example, in this embodiment, the first threshold value is Figure 3 The second threshold is 60, the unit is mL / g), and the generated adjustment instruction implements the following second process control operation:

[0136] The sludge in the MBR tank first enters the deoxygenation tank for deoxygenation, and then part of the sludge is returned from the deoxygenation tank to the anoxic tank (nitrification liquid internal return) through the mixed sludge internal return pipeline 2, and is returned to the anaerobic tank through the mixed sludge external return pipeline 3. Another part of the sludge enters the hydrocyclone separation device from the deoxygenation tank for treatment, and then returns to the anoxic tank (nitrification liquid internal return) through the high-density sludge internal return pipeline 6, and is returned to the anaerobic tank through the high-density sludge external return pipeline 7. The remaining sludge is discharged together through the remaining sludge discharge pipeline 4 and the light remaining sludge discharge pipeline 8;

[0137] In actual implementation, combined with Figure 2 The system configuration shown uses an inlet flow meter, an inlet TN analyzer, an aerobic zone sludge MLSS analyzer, a deoxygenation zone sludge MLSS analyzer and a sludge interface meter, a high-density sludge MLSS analyzer, a mixed sludge internal return flow meter, a mixed sludge external return flow meter, a high-density sludge internal return flow meter, and a high-density sludge external return flow meter to jointly control the internal and external return flow of the sludge; the inlet flow meter, an inlet BOD analyzer, an inlet suspended solids analyzer, a residual sludge MLSS analyzer, and a residual light sludge MLSS analyzer are used to jointly control the residual sludge discharge; specifically, in the process of realizing the second process control operation, the internal and external return flow of the sludge and the residual sludge discharge are controlled based on the following expressions:

[0138] (4)

[0139] (5)

[0140] (6)

[0141] In expressions (4) to (6),

[0142] represents the total sludge return flow, Indicates the high-density sludge external return flow rate, unit: m 3 / d,

[0143] Indicates the concentration of high-density sludge, in mg / L.

[0144] A represents the external reflow coefficient of mixed sludge, B represents the external reflow coefficient of high-density sludge,

[0145] represents the total internal sludge recycle volume, Indicates the reflow rate of high-density sludge, unit: m 3 / d,

[0146] C represents the internal recirculation coefficient of mixed sludge, D represents the internal recirculation coefficient of high-density sludge,

[0147] represents the total amount of sludge discharged, Indicates the discharge of light sludge, in kg / d;

[0148] Indicates light sludge concentration in mg / L.

[0149] E represents the mixed sludge discharge coefficient, and F represents the light sludge discharge coefficient.

[0150] It should be noted that during the second process control operation, the sum of the mixed sludge internal reflow ratio and the high-density sludge internal reflow ratio is generally controlled between 100% and 400%, and the sum of the mixed sludge external reflow ratio and the high-density sludge external reflow ratio is generally controlled between 50% and 100%. At the same time, the A, B, C, and D values ​​are adjusted based on the SVI real-time data.

[0151] For example, the external reflux A+B is between 50% and 100%, the internal reflux C+D is between 100% and 400%, and the linear interpolation method is used to adjust the ratio between A and B, C and D, and E and F according to the SVI value of 80 to 100 mL / g. For example, when the SVI value is 90 mL / g, that is, the six coefficients are all at the median value of 0.5, this implementation can be performed by the program built into the processing component (such as the PLC program in this embodiment).

[0152] like Figure 3 As shown, when the sludge SVI value is greater than the second threshold value (such as in this embodiment, the second threshold value is Figure 3 80 shown in , unit is mL / g), the generated adjustment instruction implements the following third process control operation:

[0153] The sludge in the MBR tank first enters the deoxygenation tank for oxygen removal. To improve the sedimentation performance, all the sludge then enters the hydrocyclone separation device from the deoxygenation tank for treatment, and then flows back to the anoxic tank through the high-density sludge internal return pipeline 6, that is, the nitrification liquid internal return, and flows back to the anaerobic tank through the high-density sludge external return pipeline 7, and the remaining sludge is discharged through the light remaining sludge discharge pipeline 8;

[0154] In actual implementation, combined with Figure 2 The system configuration shown uses an inlet flow meter, an inlet TN analyzer, a deoxygenation zone sludge MLSS analyzer and a sludge interface meter, a high-density sludge internal reflow flow meter, a high-density sludge external reflow flow meter, an effluent NO3-N analyzer, and a high-density sludge MLSS analyzer to jointly control the internal and external reflow volumes of the sludge; and uses an inlet flow meter, an inlet BOD analyzer, an inlet suspended solids analyzer, and a residual light sludge MLSS analyzer to jointly control the residual sludge discharge volume; specifically, in the process of realizing the third process control operation, the internal and external reflow volumes of the sludge and the residual sludge discharge volume are controlled based on the following expressions:

[0155] (7)

[0156] (8)

[0157] (9)

[0158] (10)

[0159] In expressions (7) to (10),

[0160] SV represents the sludge settling ratio of the deoxygenation tank, unit: %

[0161] represents the volume of the hypoxic pool, Indicates the volume of the MABR tank, in m 3 ,

[0162] It indicates the denitrification rate, in units of kgNO3-N / (kgMLSS·d),

[0163] Indicates the outlet water NO3-N concentration in mg / L.

[0164] It should also be noted that in the third process control operation, the internal reflow ratio of high-density sludge is generally controlled between 100% and 400%, and the external reflow ratio of high-density sludge is generally controlled between 50% and 100%. At the same time, the internal and external reflow volumes are adjusted based on feedback from SVI real-time data.

[0165] Based on the above system configuration, a hydrocyclone separation device is set after the deoxygenation zone to screen out high-density sludge and light sludge. Combined with relevant control methods, the screened high-density sludge is used for internal and external sludge reflow, and the light sludge is used for residual sludge discharge, which can effectively improve the sludge settling performance of the biochemical treatment system.

[0166] In one embodiment, a certain urban sewage treatment plant applies the technical solution proposed in this application and adopts "anaerobic tank-anoxic tank-MABR tank-aerobic tank-MBR tank" as a biochemical treatment system, wherein the MBR adopts a high-flux membrane module with a membrane flux of 36LMH; the MBR tank is connected to a deoxygenation tank and a hydrocyclone separation device for internal and external sludge recirculation; the effluent water quality requirement can meet the Class A standard or higher standard in the "Pollutant Discharge Standard for Urban Sewage Treatment Plants";

[0167] In this embodiment, combined Figure 2 As shown, in a control process, the data of the deoxygenation zone sludge interface meter 5a3 is used, and the sludge SVI value calculated is 82 mL / g. All the sludge from the deoxygenation tank enters the hydrocyclone separation device through the deoxygenation sludge pump 5b1 for sludge screening. After screening, the high-density sludge concentration is 20.2 g / L and the high-density sludge SVI is 35 mL / g through the high-density sludge MLSS analyzer 5b3. The high-density sludge is returned to the anoxic tank through the high-density sludge internal reflux pump 601 and returned to the anaerobic tank through the high-density sludge external reflux pump 701; the light sludge is discharged from the top of the hydrocyclone separation device through the residual light sludge discharge pump 803 to the system, and the light sludge concentration is 9.8 g / L and the light sludge SVI is 102 mL / g through the light sludge MLSS analyzer 801, which proves that the technical solution effectively solves the problem of poor sludge settling performance.

[0168] In this embodiment, the membrane flux of MBR is 36 LMH. Under the same boundary conditions, compared with the traditional AAO+secondary sedimentation tank process, the land area is saved by at least 50%; compared with the traditional AAO+MBR process, the energy consumption is reduced by at least 30%.

[0169] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the technology within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A control method for a land-saving low-carbon sewage treatment system, characterized in that: The land-saving low-carbon sewage treatment system comprises a biochemical treatment system consisting of an anaerobic tank, an anoxic tank, an aerobic tank and an MBR tank connected in sequence, wherein the MBR tank is connected in sequence with a deoxygenation tank and a hydrocyclone separation device; The land-saving low-carbon sewage treatment system also includes: Monitoring components, which are used to collect, The flow rate and water quality parameters of the inlet and outlet water of the biochemical treatment system, the sludge parameters in the aerobic tank and the deoxygenation tank, the sludge parameters of the excess sludge discharged from the MBR tank, the flow parameters of the mixed sludge returned from inside and outside the deoxygenation tank to the biochemical treatment system, the flow parameters of the high-density sludge returned from inside and outside the hydrocyclone separation device to the biochemical treatment system, and the sludge parameters of the excess light sludge discharged from the upper end of the hydrocyclone separation device; A processing component, which is used to receive and analyze the collected data of the monitoring component and generate adjustment instructions; A control component, which is used to perform single-stage internal and external reflow control of mixed sludge and high-density sludge according to the adjustment instruction action to realize the control method; in, The monitoring component comprises an inlet flow meter (101) arranged on the inlet and outlet process pipelines (1) of the biochemical treatment system, an inlet BOD analyzer (102), an inlet suspended solids analyzer (103), an inlet TN analyzer (104), an outlet NO3-N analyzer (106), and an aerobic tank MLSS analyzer (105) arranged at the aerobic tank; A mixed sludge internal return pipeline (2) is provided between the deoxygenation tank and the anoxic tank, the regulating component comprises a mixed sludge internal return pump (201) and a mixed sludge internal return valve (202) provided on the mixed sludge internal return pipeline (2), and the monitoring component further comprises a mixed sludge internal return flow meter (203) provided on the mixed sludge internal return pipeline (2); A mixed sludge external return pipeline (3) is provided between the deoxygenation tank and the anaerobic tank, the control component further comprises a mixed sludge external return pump (301) and a mixed sludge external return valve (302) provided on the mixed sludge external return pipeline (3), and the monitoring component further comprises a mixed sludge external return flow meter (303) provided on the mixed sludge external return pipeline (3); The monitoring component further comprises a residual sludge MLSS analyzer (401) and a residual sludge discharge flowmeter (404) arranged on the residual sludge discharge pipeline (4); the regulating component further comprises a residual sludge discharge pump (402) and a residual sludge discharge valve (403) arranged on the residual sludge discharge pipeline (4); The control component also includes a deoxygenation tank mud inlet valve (5a1) arranged on the first mud inlet pipeline (5a) connecting the deoxygenation tank to the MBR tank, and the monitoring component also includes a deoxygenation tank sludge MLSS analyzer (5a2) and a deoxygenation tank sludge interface meter (5a3) arranged at the deoxygenation tank; The control component also includes a deoxygenated sludge pump (5b1) and a hydrocyclone sludge inlet valve (5b2) arranged on the second sludge inlet pipeline (5b) connecting the hydrocyclone separator to the deoxygenation tank, and the monitoring component also includes a high-density sludge MLSS analyzer (5b3) arranged at the high-density sludge discharge outlet at the bottom of the hydrocyclone separator; A high-density sludge internal return pipeline (6) is provided between the hydrocyclone separation device and the anoxic tank, the regulating component further comprises a high-density sludge internal return pump (601) and a high-density sludge internal return valve (602) provided on the high-density sludge internal return pipeline (6), and the monitoring component further comprises a high-density sludge internal return flow meter (603) provided on the high-density sludge internal return pipeline (6); A high-density sludge external return pipeline (7) is also provided between the hydrocyclone separation device and the anaerobic tank, the control component further comprises a high-density sludge external return pump (701) and a high-density sludge external return valve (702) provided on the high-density sludge external return pipeline (7), and the monitoring component further comprises a high-density sludge external return flow meter (703) provided on the high-density sludge external return pipeline (7); The monitoring component further comprises a light sludge MLSS analyzer (801) and a residual light sludge discharge flowmeter (802) arranged on the light residual sludge discharge pipeline (8) of the hydrocyclone separation device, and the regulating component further comprises a residual light sludge discharge pump (803) and a residual light sludge discharge valve (804) arranged on the light residual sludge discharge pipeline (8); In the biochemical treatment system, a MABR tank is also provided between the anoxic tank and the aerobic tank; The control method includes: Based on the monitoring data of the deoxygenation tank sludge MLSS analyzer (5a2) and the deoxygenation tank sludge interface meter (5a3), the SVI value of the deoxygenation tank sludge is calculated and determined; According to the threshold range of the sludge SVI value, an adjustment instruction is generated to implement a corresponding control process operation; When the sludge SVI value is less than or equal to the first threshold value, the generated adjustment instruction implements the following first process control operation: the sludge in the MBR tank first enters the deoxygenation tank to remove oxygen, and then directly returns from the deoxygenation tank to the anoxic tank through the mixed sludge internal return pipeline (2), and returns to the anaerobic tank through the mixed sludge external return pipeline (3), and the remaining sludge is discharged through the remaining sludge discharge pipeline (4); When the sludge SVI value is greater than the first threshold value and less than or equal to the second threshold value, the generated adjustment instruction implements the following second process control operation: the sludge in the MBR tank first enters the deoxygenation tank for deoxygenation, and then part of the sludge is returned from the deoxygenation tank to the anoxic tank through the mixed sludge internal return pipeline (2), and is returned to the anaerobic tank through the mixed sludge external return pipeline (3), and another part of the sludge enters the hydrocyclone separation device from the deoxygenation tank for treatment, and then is returned to the anoxic tank through the high-density sludge internal return pipeline (6), and is returned to the anaerobic tank through the high-density sludge external return pipeline (7), and the remaining sludge is discharged together through the remaining sludge discharge pipeline (4) and the light remaining sludge discharge pipeline (8); When the sludge SVI value is greater than the second threshold value, the generated adjustment instruction implements the following third process control operation: the sludge in the MBR tank first enters the deoxygenation tank for oxygen removal, and then all the sludge enters the hydrocyclone separation device from the deoxygenation tank for treatment, and then returns to the anoxic tank through the high-density sludge internal return pipeline (6), and returns to the anaerobic tank through the high-density sludge external return pipeline (7), and the remaining sludge is discharged through the light remaining sludge discharge pipeline (8).

2. The control method according to claim 1, wherein: During the implementation of the first process control operation, the internal and external reflux amounts of sludge and the discharge amount of excess sludge are controlled based on the following expressions: in, represents the return flow rate in the mixed sludge, Indicates the real-time flow rate of water inlet, unit: m 3 / d, Indicates the real-time TN concentration of the influent water. Indicates the TN target value of the outlet water, in mg / L. Indicates the mixed sludge external return flow rate, unit: m 3 / d, Indicates the MLSS concentration of aerobic tank sludge, Indicates the MLSS concentration of deoxygenation tank sludge, in mg / L. Indicates the amount of residual sludge discharged, in kg / d; It represents the sludge yield coefficient, unit is kgVSS / kgBOD5; Indicates the real-time BOD concentration of the influent. Indicates the target value of effluent BOD, in mg / L; Indicates the conversion rate between SS and MLSS, unit: gMLSS / gSS, Indicates the real-time SS concentration of the influent water. Indicates the outlet SS target value, in mg / L. Indicates the sludge attenuation coefficient, unit d -1 , V represents the total volume of the biochemical system, in m 3 , It indicates the residual sludge concentration of mixed sludge, in mg / L.

3. The control method according to claim 2, wherein: During the implementation of the second process control operation, the internal and external reflux amounts of sludge and the discharge amount of excess sludge are controlled based on the following expressions: in, represents the total sludge return flow, Indicates the high-density sludge external return flow rate, unit: m 3 / d, Indicates the concentration of high-density sludge, in mg / L. A represents the external reflow coefficient of mixed sludge, B represents the external reflow coefficient of high-density sludge, represents the total internal sludge recycle volume, Indicates the reflow rate of high-density sludge, unit: m 3 / d, C represents the internal recirculation coefficient of mixed sludge, D represents the internal recirculation coefficient of high-density sludge, represents the total amount of sludge discharged, Indicates the discharge of light sludge, in kg / d; Indicates light sludge concentration in mg / L. E represents the mixed sludge discharge coefficient, and F represents the light sludge discharge coefficient.

4. The control method according to claim 3, wherein: During the implementation of the third process control operation, the internal and external reflux amounts of sludge and the discharge amount of excess sludge are controlled based on the following expressions: in, SV represents the sludge settling ratio of the deoxygenation tank, unit: % represents the volume of the hypoxic pool, Indicates the volume of the MABR tank, in m 3 , It indicates the denitrification rate, in units of kgNO3-N / (kgMLSS·d), Indicates the outlet water NO3-N concentration in mg / L.

5. The control method according to claim 1, wherein: Each pump device in the control component adopts a variable frequency pump.

6. The control method according to claim 1, wherein: The membrane flux range of the membrane module used in the MBR pool is 30 to 40LMH.

7. The control method according to claim 1, wherein: The processing component is implemented based on a PLC controller.

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