Water treatment system and water treatment method

Abstract

The present invention discloses a water treatment system and a water treatment method, wherein the water treatment system is formed by sequentially connecting an anaerobic zone, an aerobic zone, a variable zone, an anoxic zone and a membrane bioreactor; the anaerobic zone is used to provide an anaerobic environment; the aerobic zone is used to provide an aerobic environment; the variable zone is used to determine the target judgment interval in which the monitoring index data is located according to the monitoring index data of the water and a plurality of judgment intervals, and adjust the dissolved oxygen concentration of the variable zone to a preset interval corresponding to the target judgment interval according to the target judgment interval; the anoxic zone is used to provide an anoxic environment; and the membrane bioreactor is used to perform solid-liquid separation treatment on the water to obtain treated water. In this application, the anoxic zone is placed after the aerobic zone, so that the water treatment system does not need to reflux the nitrification liquid, which saves a lot of operating energy consumption, and the variable zone can realize the efficient use of dissolved oxygen in the water, thereby reducing the aeration energy consumption, thereby reducing the total energy consumption of the water treatment system, and at the same time improving the sewage treatment effect.

Description

Technical Field

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

[0002] In the field of urban sewage treatment, it is generally necessary to remove nitrogen and phosphorus from sewage. How to achieve efficient nitrogen and phosphorus removal while reducing energy consumption and greenhouse gas emissions has always been the focus of attention in the industry.

[0003] At present, the sewage treatment method adopted by most cities in China is the pre-denitrification method of sewage denitrification and phosphorus removal represented by AAO (Anaerobic-Anoxic-Oxic). The AAO water treatment system is composed of anaerobic zone-anoxic zone-aerobic zone in series. The AAO sewage treatment method combines anaerobic biological treatment methods and aerobic biological treatment methods, mainly through biochemical reactions at different stages to effectively remove nitrogen and organic pollutants in sewage. In the AAO water treatment system, it is generally necessary to return the nitrification liquid in the aerobic zone to the anoxic zone to increase the nitrate nitrogen concentration in the anoxic zone, thereby promoting the denitrification reaction in the anoxic zone to reduce the total nitrogen concentration in the water. In addition, in order to use aerobic microorganisms to treat sewage, it is generally necessary to use an aeration device to provide dissolved oxygen to the water body.

[0004] However, in the AAO water treatment system, the energy consumption required for nitrification liquid recirculation and aeration is relatively high, so the total energy consumption of the AAO water treatment system is high, which often leads to the dual pressure of improving quality and efficiency and saving energy and reducing consumption in urban sewage treatment. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present application provides a water treatment system and a water treatment method, in which the water to be treated flows through an anaerobic zone, an aerobic zone, a variable zone, an anoxic zone and a membrane bioreactor in sequence, and the anoxic zone is placed after the aerobic zone. The water treatment system does not need to reflux nitrification liquid, thereby saving a large amount of operating energy consumption, and the variable zone is also used to adjust the dissolved oxygen concentration in the variable zone to a preset interval corresponding to the target judgment interval according to the target judgment interval, so as to provide an anoxic environment, a microoxic environment or an aerobic environment for the microorganisms in the variable zone, thereby adjusting the main reactions of the microorganisms in the variable zone, and realizing efficient utilization of dissolved oxygen in water, thereby reducing aeration energy consumption, thereby reducing the total energy consumption of the water treatment system, and at the same time improving the sewage treatment effect.

[0006] To solve the above problems, the present invention provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a water treatment system, wherein the water treatment system is formed by sequentially connecting an anaerobic zone, an aerobic zone, a variable zone, an anoxic zone, and a membrane bioreactor, and the water to be treated flows sequentially through the anaerobic zone, the aerobic zone, the variable zone, the anoxic zone, and the membrane bioreactor;

[0008] The anaerobic zone is used to provide an anaerobic environment so that the microorganisms in the anaerobic zone can release phosphorus and synthesize intracellular carbon sources using organic matter in the water to be treated;

[0009] The aerobic zone is used to provide an aerobic environment so that the microorganisms in the aerobic zone can utilize the mud-water mixture in the aerobic zone to perform aerobic phosphorus absorption reaction, nitrification reaction and simultaneous nitrification and denitrification reaction;

[0010] The variable area is used to determine the target judgment interval in which the monitoring index data is located according to the water monitoring index data and a plurality of judgment intervals, wherein each of the judgment intervals corresponds to a preset interval of dissolved oxygen concentration;

[0011] The variable region is also used to adjust the dissolved oxygen concentration of the variable region to a preset range corresponding to the target judgment range according to the target judgment range, so as to provide an anoxic environment, a microoxic environment or an aerobic environment for the microorganisms in the variable region, thereby adjusting the reaction mainly performed by the microorganisms in the variable region;

[0012] The anoxic zone is used to provide an anoxic environment so that the microorganisms in the anoxic zone can use the mud-water mixture in the anoxic zone to perform endogenous denitrification reaction;

[0013] The membrane biological reaction tank is used to perform solid-liquid separation treatment on the mud-water mixture in the membrane biological reaction tank to obtain treated water.

[0014] In some embodiments, the aerobic zone is provided with a semi-soft filler, the semi-soft filler is used to increase the number of microorganisms in the aerobic zone, the semi-soft filler is suspended in the aerobic zone through a bracket, the semi-soft filler has a structure that facilitates the attachment of microorganisms in the aerobic zone, the filling rate of the semi-soft filler is 80% to 90%, and the specific surface area of ​​the semi-soft filler is 80m 2 / m 3 Up to 120m 2 / m 3 .

[0015] In some embodiments, the anaerobic zone is provided with a first stirring device, and the first stirring device is used to make the mud-water mixture in the anaerobic zone in a suspension state;

[0016] The aerobic zone is provided with a first aeration device and a first monitoring instrument, wherein the first aeration device is used to increase the dissolved oxygen concentration in the aerobic zone, and the first monitoring instrument is used to obtain monitoring index data of water in the aerobic zone;

[0017] The variable zone is provided with a second stirring device, a second aeration device and a second monitoring instrument, the second stirring device is used to make the mud-water mixture in the variable zone in a suspension state, the second aeration device is used to increase the dissolved oxygen concentration in the variable zone, and the second monitoring instrument is used to monitor the dissolved oxygen concentration in the variable zone;

[0018] The anoxic zone is provided with a third stirring device, and the third stirring device is used to make the mud-water mixture in the anoxic zone in a suspension state;

[0019] The membrane biological reaction tank is provided with a third aeration device, and the third aeration device is used to drive water to flush the membrane components in the membrane biological reaction tank through airflow, so as to reduce solids attached to the membrane components.

[0020] In some embodiments, the monitoring index data includes the ammonia nitrogen concentration of the water at the end of the aerobic zone, the multiple judgment intervals include a first judgment interval, a second judgment interval and a third judgment interval, the first judgment interval corresponds to a first preset interval, the second judgment interval corresponds to a second preset interval, and the third judgment interval corresponds to a third preset interval;

[0021] When the ammonia nitrogen concentration is in the first judgment interval, the variable region is further used to adjust the dissolved oxygen concentration in the variable region to within the first preset interval, so that the variable region provides the anoxic environment for the microorganisms in the variable region;

[0022] When the ammonia nitrogen concentration is in the second judgment interval, the variable region is further used to adjust the dissolved oxygen concentration in the variable region to the second preset interval, so that the variable region provides the micro-aerobic environment for the microorganisms in the variable region;

[0023] When the ammonia nitrogen concentration is in the third judgment interval, the variable region is also used to adjust the dissolved oxygen concentration in the variable region to the third preset interval, so that the variable region provides the aerobic environment for the microorganisms in the variable region.

[0024] In some embodiments, the first judgment interval is that the ammonia nitrogen concentration is less than 1 mg / L, the second judgment interval is that the ammonia nitrogen concentration is greater than or equal to 1 mg / L and less than 3 mg / L, the third judgment interval is that the ammonia nitrogen concentration is greater than or equal to 3 mg / L, the first preset interval is that the dissolved oxygen concentration in the variable area is less than 0.5 mg / L, the second preset interval is that the dissolved oxygen concentration in the variable area is greater than or equal to 1 mg / L and less than 1.5 mg / L, and the third preset interval is that the dissolved oxygen concentration in the variable area is greater than or equal to 1.5 mg / L and less than or equal to 2 mg / L.

[0025] In some embodiments, a first return pipe is provided between the anaerobic zone and the anoxic zone, a first return pump is provided in the first return pipe, and the first return pump is used to pump the muddy-water mixture in the anoxic zone into the anaerobic zone through the first return pipe, wherein the muddy-water mixture in the anoxic zone includes microorganisms in the anoxic zone, and the redox potential of the anaerobic zone is -200mV to -300mV;

[0026] A second reflux pipe is arranged between the aerobic zone and the membrane biological reactor, and a second reflux pump is arranged in the second reflux pipe. The second reflux pump is used to pump the mud-water mixture of the membrane biological reactor into the aerobic zone through the second reflux pipe, wherein the mud-water mixture of the membrane biological reactor includes the microorganisms in the membrane biological reactor.

[0027] In some embodiments, the first reflux ratio corresponding to the first reflux pipeline is 100% to 200%, and the second reflux ratio corresponding to the second reflux pipeline is 200% to 400%;

[0028] The residence time of water in the anaerobic zone is 2 to 4 hours, and the residence time of water in the aerobic zone is 2 to 4 hours;

[0029] The volume ratio of the anaerobic zone, the aerobic zone, the variable zone and the anoxic zone is 2:2:1:4.

[0030] In some embodiments, when the influent TN concentration is greater than or equal to 80 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 10 mg / L, the aerobic zone is further used to control the dissolved oxygen concentration of the aerobic zone to be 3.5 mg / L to 4 mg / L;

[0031] When the influent TN concentration is greater than or equal to 50 mg / L and less than 80 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 6 mg / L and less than 10 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration of the aerobic zone to be 2.5 mg / L to 3.5 mg / L;

[0032] When the influent TN concentration is greater than or equal to 30 mg / L and less than 50 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 3 mg / L and less than 6 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration of the aerobic zone to be 2 mg / L to 2.5 mg / L;

[0033] When the influent TN concentration is less than 30 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is less than 3 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration of the aerobic zone to be 1.5 mg / L to 2 mg / L;

[0034] The sludge concentration in the aerobic zone is 3500 mg / L to 5500 mg / L;

[0035] The sludge concentration in the anoxic zone is 4000 mg / L to 6000 mg / L;

[0036] The dissolved oxygen concentration of the membrane biological reactor is 3.5 mg / L to 6.0 mg / L, and the sludge concentration of the membrane biological reactor is 6000 mg / L to 9000 mg / L.

[0037] In a second aspect, an embodiment of the present application provides a water treatment method, which is applied to the water treatment system as described in the first aspect, and the method includes:

[0038] Injecting the water to be treated into an anaerobic zone for treatment, wherein the anaerobic zone is used to provide an anaerobic environment so that the microorganisms in the anaerobic zone can release phosphorus and synthesize intracellular carbon sources using organic matter in the water to be treated;

[0039] The mud-water mixture at the end of the anaerobic zone is injected into the aerobic zone for treatment, wherein the aerobic zone is used to provide an aerobic environment so that the microorganisms in the aerobic zone can utilize the mud-water mixture in the aerobic zone to perform aerobic phosphorus absorption reaction, nitrification reaction and simultaneous nitrification and denitrification reaction;

[0040] The mud-water mixture at the end of the aerobic zone is injected into the variable zone for treatment, and the variable zone is used to determine the target judgment interval in which the monitoring index data is located according to the water monitoring index data and multiple judgment intervals, wherein each of the judgment intervals corresponds to a preset interval of dissolved oxygen concentration, and the variable zone is also used to adjust the dissolved oxygen concentration of the variable zone to the preset interval corresponding to the target judgment interval according to the target judgment interval, so as to provide an anoxic environment, a microoxic environment or an aerobic environment for the microorganisms in the variable zone, thereby adjusting the main reaction of the microorganisms in the variable zone;

[0041] Injecting the muddy water mixture at the end of the variable zone into the anoxic zone for treatment, wherein the anoxic zone is used to provide an anoxic environment so that the microorganisms in the anoxic zone can use the muddy water mixture in the anoxic zone to perform endogenous denitrification reaction;

[0042] The mud-water mixture at the end of the anoxic zone is injected into a membrane bioreactor for solid-liquid separation to obtain treated water.

[0043] In some embodiments, the monitoring index data includes the ammonia nitrogen concentration of the water at the end of the aerobic zone, the multiple judgment intervals include a first judgment interval, a second judgment interval and a third judgment interval, the first judgment interval corresponds to a first preset interval, the second judgment interval corresponds to a second preset interval, and the third judgment interval corresponds to a third preset interval;

[0044] The step of injecting the muddy water mixture at the end of the aerobic zone into the variable zone for treatment comprises:

[0045] injecting the mud-water mixture at the end of the aerobic zone into the variable zone;

[0046] When the ammonia nitrogen concentration is within the first judgment interval, adjusting the dissolved oxygen concentration of the variable region to within the first preset interval, so that the variable region provides the anoxic environment for the microorganisms in the variable region;

[0047] When the ammonia nitrogen concentration is in the second judgment interval, adjusting the dissolved oxygen concentration in the variable region to the second preset interval, so that the variable region provides the micro-aerobic environment for the microorganisms in the variable region;

[0048] When the ammonia nitrogen concentration is in the third judgment interval, the dissolved oxygen concentration of the variable zone is adjusted to the third preset interval so that the variable zone provides the aerobic environment for the microorganisms in the variable zone.

[0049] The present application provides a water treatment system and a water treatment method. In the present application, water to be treated flows through an anaerobic zone, an aerobic zone, a variable zone, an anoxic zone and a membrane biological reaction tank in sequence. The anoxic zone is placed after the aerobic zone. The water treatment system does not need to reflux nitrification liquid, which saves a lot of operating energy consumption. The variable zone is also used to adjust the dissolved oxygen concentration in the variable zone to a preset interval corresponding to the target judgment interval according to the target judgment interval, so as to provide an anoxic environment, a microoxic environment or an aerobic environment for the microorganisms in the variable zone, thereby adjusting the main reactions of the microorganisms in the variable zone, and realizing efficient utilization of dissolved oxygen in water, thereby reducing aeration energy consumption, thereby reducing the total energy consumption of the water treatment system, and at the same time improving the sewage treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1It is a schematic diagram of the structure of the water treatment system provided in the embodiment of the present application.

[0051] Figure 2 It is a schematic flow chart of the water treatment method provided in the embodiment of the present application.

[0052] Figure 3 yes Figure 2 Detailed flowchart of step S300. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0054] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0055] The present application provides a water treatment system and a water treatment method, wherein water to be treated flows through an anaerobic zone, an aerobic zone, a variable zone, an anoxic zone and a membrane biological reaction tank in sequence, and the anoxic zone is placed after the aerobic zone. The water treatment system does not need to reflux nitrification liquid, thereby saving a large amount of operating energy consumption, and the variable zone is also used to adjust the dissolved oxygen concentration in the variable zone to a preset interval corresponding to the target judgment interval according to the target judgment interval, so as to provide an anoxic environment, a microoxic environment or an aerobic environment for the microorganisms in the variable zone, thereby adjusting the main reactions of the microorganisms in the variable zone, and realizing efficient utilization of dissolved oxygen in water, thereby reducing aeration energy consumption, thereby reducing the total energy consumption of the water treatment system, and at the same time improving the sewage treatment effect.

[0056] The water treatment system provided by the present application will be described in detail below with reference to the accompanying drawings.

[0057] See also Figure 1 , Figure 1 Schematic diagram of the structure of the water treatment system provided in the embodiment of the present application. Figure 1As shown, in some embodiments, the water treatment system 100 is formed by sequentially connecting an anaerobic zone 110, an aerobic zone 120, a variable zone 130, an anoxic zone 140 and a membrane bioreactor 150, and the water 1 to be treated flows through the anaerobic zone 110, the aerobic zone 120, the variable zone 130, the anoxic zone 140 and the membrane bioreactor 150 in sequence, and the treated water 2 flows out of the membrane bioreactor 150. The water 1 to be treated can also be called influent, and the treated water 2 can also be called effluent.

[0058] In some embodiments, each zone in the water treatment system is separated by a barrier with drainage holes or pipes provided on the barrier to allow water to flow.

[0059] In some embodiments, the anaerobic zone is used to provide an anaerobic environment so that the microorganisms in the anaerobic zone can release phosphorus and synthesize intracellular carbon sources using organic matter in the water to be treated. That is, the anaerobic zone uses the microorganisms in the anaerobic zone to absorb organic matter in the water to be treated.

[0060] In some embodiments, the anaerobic environment causes the microorganisms in the anaerobic zone to mainly perform a phosphorus release reaction. The phosphorus release reaction refers to the process in which the microorganisms decompose the polyphosphate stored in the cell into inorganic phosphate and release it into the water body. The microorganisms in the anaerobic zone perform a phosphorus release reaction and convert external carbon sources such as volatile organic acids in the influent into internal carbon sources stored in the cell body.

[0061] like Figure 1 As shown, in some embodiments, the anaerobic zone 110 is provided with a first stirring device 111, and the first stirring device 111 is used to make the mud-water mixture in the anaerobic zone 110 in a suspension state.

[0062] In some embodiments, the solids in the water mainly include microorganisms, and the solids may also be referred to as sludge.

[0063] By making the mud-water mixture in the anaerobic zone in a suspension state, the sludge including microorganisms in the anaerobic zone can be fully mixed with water, which is beneficial for fully treating the water by utilizing the microorganisms in the anaerobic zone.

[0064] In some embodiments, the residence time of water in the anaerobic zone is from 2 h (hours) to 4 h.

[0065] In some embodiments, the redox potential of the anaerobic zone is -200 mV (millivolts) to -300 mV. Oxidation-Reduction Potential (ORP) is an indicator of the tendency of redox reactions in water, which is used to reflect the state of chemical balance between oxidizable and reducible substances in water.

[0066] In some embodiments, the dissolved oxygen concentration in the anaerobic zone is less than 0.2 mg / L (milligrams per liter).

[0067] like Figure 1 As shown, in some embodiments, the muddy water mixture flowing out of the anaerobic zone 110 flows into the aerobic zone 120 .

[0068] In some embodiments, the aerobic zone is used to provide an aerobic environment so that the microorganisms in the aerobic zone use the mud-water mixture in the aerobic zone to perform aerobic phosphorus absorption reaction, nitrification reaction and simultaneous nitrification and denitrification reaction. Aerobic phosphorus absorption reaction, nitrification reaction and simultaneous nitrification and denitrification reaction are all biochemical reaction processes. During the aerobic phosphorus absorption reaction, polyphosphate bacteria absorb phosphorus and synthesize polyphosphate, store phosphate in the form of polyphosphate in the cell, and remove phosphate from the water. During the nitrification reaction, nitrifying bacteria oxidize ammonia nitrogen (referring to free ammonia and ammonium ions) in the water into nitrite ions or nitrate ions. The simultaneous nitrification and denitrification reaction is a denitrification reaction that is carried out simultaneously with the nitrification reaction. During the denitrification reaction, denitrifying bacteria reduce nitrate ions or nitrite ions to nitrogen gas and release them into the atmosphere.

[0069] like Figure 1 As shown, in some embodiments, the aerobic zone 120 is provided with a semi-soft filler 121 , and the semi-soft filler 121 is used to increase the number of microorganisms in the aerobic zone 120 .

[0070] Semi-soft filler is a kind of filler used for treating water bodies, which has physical properties between hard filler and soft filler. Semi-soft filler is usually made of special plastic material, with good mechanical strength, chemical stability and biocompatibility.

[0071] like Figure 1 As shown, in some embodiments, the semi-soft filler 121 is suspended in the aerobic zone 120 by a bracket.

[0072] Optionally, the semi-soft filler has a structure that facilitates the attachment of microorganisms in the aerobic zone.

[0073] Optionally, the semi-soft filler has a snowflake-like structure or a waterweed-like structure connected by fiber ropes, etc.

[0074] Optionally, the filling rate of the semi-soft filler is 80% to 90%.

[0075] Optionally, the specific surface area of ​​the semi-soft filler is 80m 2 / m 3 (square meters / cubic meters) to 120m 2 / m 3 .

[0076] Through the above method, it is easy to make the sludge in the aerobic zone adhere to the semi-soft filler, thereby increasing the total amount of microorganisms in the aerobic zone and improving the efficiency of sewage treatment using microorganisms in the aerobic zone. Compared with conventional AAO (Anaerobic-Anoxic-Oxic, anaerobic-anoxic-aerobic) and other sewage treatment methods, it can save about half of the aerobic zone volume, thereby reducing the aeration energy consumption of the aerobic zone. In addition, the structural form of the semi-soft filler will cause a certain range of anoxic environment in the aerobic zone, which can strengthen the simultaneous nitrification and denitrification reaction in the aerobic zone.

[0077] In some embodiments, the residence time of the water in the aerobic zone is from 2 hours to 4 hours.

[0078] like Figure 1 As shown, in some embodiments, the aerobic zone 120 is provided with a first aeration device 160 and a first monitoring instrument 123 .

[0079] Optionally, the first aeration device is used to increase the dissolved oxygen concentration in the aerobic zone, and the first monitor is used to obtain monitoring index data of water in the aerobic zone.

[0080] like Figure 1 As shown, in some embodiments, the aerobic zone 120 is further provided with a third monitor 122 , and the third monitor 122 is used to monitor the dissolved oxygen concentration in the aerobic zone 120 .

[0081] Optionally, the first monitor may also be used to monitor the dissolved oxygen concentration in the aerobic zone.

[0082] Optionally, the monitoring index data of the water in the aerobic zone includes the ammonia nitrogen concentration of the water. The ammonia nitrogen concentration of the water refers to the concentration of nitrogen in the water in the form of free ammonia and ammonium ions.

[0083] like Figure 1 As shown, optionally, the first monitor 123 is disposed at the end of the aerobic zone 120 to monitor the ammonia nitrogen concentration of the water at the end of the aerobic zone 120 .

[0084] In some embodiments, the anaerobic zone is provided with a fourth monitor, which is used to obtain monitoring index data of the incoming water.

[0085] Optionally, the monitoring index data of the influent includes the influent TN concentration. The influent TN concentration (Total Nitrogen) refers to the concentration of total nitrogen in the influent. Total nitrogen refers to the sum of nitrogen elements in the form of ammonia nitrogen, nitrate nitrogen, nitrite nitrogen and organic nitrogen (such as protein and amino acids, etc.).

[0086] In some embodiments, when the influent TN concentration is greater than or equal to 80 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 10 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration in the aerobic zone to 3.5 mg / L to 4 mg / L.

[0087] In some embodiments, when the inlet TN concentration is greater than or equal to 50 mg / L and less than 80 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 6 mg / L and less than 10 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration in the aerobic zone to 2.5 mg / L to 3.5 mg / L.

[0088] In some embodiments, when the inlet TN concentration is greater than or equal to 30 mg / L and less than 50 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 3 mg / L and less than 6 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration in the aerobic zone to 2 mg / L to 2.5 mg / L.

[0089] In some embodiments, when the influent TN concentration is less than 30 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is less than 3 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration in the aerobic zone to 1.5 mg / L to 2 mg / L.

[0090] In some embodiments, the first monitor is connected to the first aeration device, and the first monitor is used to control the operating state of the first aeration device according to the acquired monitoring index data of the water in the aerobic zone and the dissolved oxygen concentration in the aerobic zone, so as to control the dissolved oxygen concentration in the aerobic zone. For example, when it is necessary to increase the dissolved oxygen concentration in the aerobic zone, the aeration intensity of the first aeration device is increased to inject more oxygen into the aerobic zone. When it is necessary to reduce the dissolved oxygen concentration in the aerobic zone, the aeration intensity of the first aeration device is reduced or the first aeration device is turned off.

[0091] In some embodiments, the first monitor is connected to the first aeration device, and the first monitor is used to control the operating state of the first aeration device according to the acquired monitoring index data of the water in the aerobic zone, so as to control the dissolved oxygen concentration in the aerobic zone.

[0092] Optionally, a target interval of dissolved oxygen concentration in an aerobic zone corresponds to a preset operating state of a first aeration device. The first monitor is used to determine the target interval of dissolved oxygen concentration in the aerobic zone based on monitoring index data of water in the aerobic zone, and control the first aeration device to be in the preset operating state corresponding to the target interval to control the dissolved oxygen concentration in the aerobic zone.

[0093] Optionally, the correspondence between the target range of dissolved oxygen concentration in the aerobic zone and the preset operating state of the first aeration device is determined by experiment.

[0094] In some embodiments, the first monitor is connected to the third monitor and the first aeration device respectively, and the first monitor is used to control the operating state of the first aeration device according to the acquired monitoring index data of the water in the aerobic zone and the dissolved oxygen concentration in the aerobic zone to control the dissolved oxygen concentration in the aerobic zone.

[0095] In some embodiments, the first monitor is connected to the third monitor, the fourth monitor and the first aeration device respectively, and the first monitor is used to control the operating state of the first aeration device according to the monitoring index data of the water in the aerobic zone and the influent, and the dissolved oxygen concentration in the aerobic zone, so as to control the dissolved oxygen concentration in the aerobic zone.

[0096] In some embodiments, the first monitor is connected to the fourth monitor and the first aeration device, and the first monitor is used to control the operating state of the first aeration device according to the monitoring index data of the water in the aerobic zone and the monitoring index data of the influent to control the dissolved oxygen concentration in the aerobic zone.

[0097] Optionally, the first monitor is used to determine a target range of dissolved oxygen concentration in the aerobic zone based on monitoring index data of water in the aerobic zone and monitoring index data of influent water, and control the first aeration device to be in a preset operating state corresponding to the target range to control the dissolved oxygen concentration in the aerobic zone.

[0098] In some embodiments, the aerobic zone is further provided with a first control device.

[0099] In some embodiments, the first control device is connected to the first monitor, the third monitor and the first aeration device, respectively, and the first control device is used to obtain the monitoring index data of the water in the aerobic zone monitored by the first monitor and the dissolved oxygen concentration in the aerobic zone monitored by the third monitor, and control the operating state of the first aeration device according to the monitoring index data of the water in the aerobic zone and the dissolved oxygen concentration in the aerobic zone to control the dissolved oxygen concentration in the aerobic zone.

[0100] In some embodiments, the first control device is connected to the first monitor, the third monitor, the fourth monitor and the first aeration device, respectively, and the first control device is used to obtain monitoring index data of water in the aerobic zone and influent, and the dissolved oxygen concentration in the aerobic zone monitored by the third monitor, and control the operating state of the first aeration device according to the monitoring index data of the aerobic zone and influent, and the dissolved oxygen concentration in the aerobic zone, so as to control the dissolved oxygen concentration in the aerobic zone.

[0101] In some embodiments, the user controls the operating state of the first aeration device according to the monitoring index data of the water in the aerobic zone and the influent water, and the dissolved oxygen concentration in the aerobic zone, so as to control the dissolved oxygen concentration in the aerobic zone.

[0102] In some embodiments, the user controls the operating state of the first aeration device according to monitoring indicator data of the water in the aerobic zone and the influent water to control the dissolved oxygen concentration in the aerobic zone.

[0103] Optionally, the user determines a target range of dissolved oxygen concentration in the aerobic zone based on monitoring index data of water in the aerobic zone and influent, and controls the first aeration device to be in a preset operating state corresponding to the target range to control the dissolved oxygen concentration in the aerobic zone.

[0104] In some embodiments, the user controls the dissolved oxygen concentration in the aerobic zone by presetting the operating state of the first aeration device.

[0105] In some embodiments, the sludge concentration in the aerobic zone is 3500 mg / L to 5500 mg / L. In this way, it is ensured that there are enough microorganisms in the aerobic zone for treating sewage.

[0106] like Figure 1 As shown, in some embodiments, the muddy water mixture flowing out of the aerobic zone 120 flows into the variable zone 130 .

[0107] like Figure 1 As shown, in some embodiments, the variable zone 130 is provided with a second stirring device 131 , a second aeration device and a second monitor 132 , the second aeration device is used to increase the dissolved oxygen concentration of the variable zone 130 , and the second monitor 132 is used to monitor the dissolved oxygen concentration of the variable zone 130 .

[0108] like Figure 1 As shown, in some embodiments, the second aeration device is the same aeration device as the first aeration device 160. In this way, equipment cost and aeration energy consumption can be saved.

[0109] In some embodiments, the aeration device includes a fan and an aeration disk.

[0110] In some embodiments, the second stirring device is used to make the mud-water mixture in the variable zone in a suspension state. In this way, the sludge including microorganisms in the variable zone can be fully mixed with water, which is conducive to fully treating the water using the microorganisms in the variable zone.

[0111] In some embodiments, the variable area is used to determine the target judgment interval in which the monitoring indicator data is located according to the monitoring indicator data of the water and a plurality of judgment intervals, wherein each judgment interval corresponds to a preset interval of dissolved oxygen concentration.

[0112] Optionally, the water monitoring index data is the water monitoring index data of the variable zone.

[0113] Optionally, the water monitoring index data is the water monitoring index data at the end of the aerobic zone.

[0114] Optionally, the water monitoring index data is water inflow monitoring index data.

[0115] Optionally, the monitoring index data of water include dissolved oxygen concentration, total nitrogen concentration, total phosphorus concentration and chemical oxygen demand (COD) concentration of water.

[0116] In some embodiments, the variable region is also used to adjust the dissolved oxygen concentration in the variable region to a preset range corresponding to the target judgment range according to the target judgment range, so as to provide anoxic environment, micro-oxic environment or aerobic environment for the microorganisms in the variable region, thereby adjusting the main reaction of the microorganisms in the variable region. In this way, the efficient use of dissolved oxygen in water can be achieved, thereby reducing aeration energy consumption, and at the same time improving the sewage treatment effect. Aeration energy consumption refers to the energy consumption of the aeration device.

[0117] In some embodiments, in an anaerobic environment, the microorganisms in the variable region mainly perform endogenous denitrification. Endogenous denitrification refers to the denitrification reaction performed by microorganisms using their own intracellular carbon source without the addition of an external organic carbon source. In this way, the water treatment system can maintain high standards of effluent quality without the need to add an external carbon source.

[0118] In some embodiments, in a microaerobic environment, the microorganisms in the variable zone mainly carry out nitrification and simultaneous nitrification and denitrification reactions.

[0119] In some embodiments, in an aerobic environment, the microorganisms in the variable zone mainly carry out aerobic phosphorus uptake reaction, nitrification reaction and simultaneous nitrification and denitrification reaction.

[0120] In some implementations, the number of determination intervals is greater than 2, for example, the number of determination intervals is 2, 3, 4, or 10.

[0121] In some implementations, the plurality of judgment intervals include a first judgment interval, a second judgment interval, and a third judgment interval, the first judgment interval corresponds to a first preset interval, the second judgment interval corresponds to a second preset interval, and the third judgment interval corresponds to a third preset interval.

[0122] In some embodiments, the water monitoring index data is the water monitoring index data in the aerobic zone, and the water monitoring index data in the aerobic zone includes the ammonia nitrogen concentration of the water at the end of the aerobic zone.

[0123] In some embodiments, the first judgment interval is that the ammonia nitrogen concentration is less than 1 mg / L, the second judgment interval is that the ammonia nitrogen concentration is greater than or equal to 1 mg / L and less than 3 mg / L, the third judgment interval is that the ammonia nitrogen concentration is greater than or equal to 3 mg / L, the first preset interval is that the dissolved oxygen concentration in the variable area is less than 0.5 mg / L, the second preset interval is that the dissolved oxygen concentration in the variable area is greater than or equal to 1 mg / L and less than 1.5 mg / L, and the third preset interval is that the dissolved oxygen concentration in the variable area is greater than or equal to 1.5 mg / L and less than or equal to 2 mg / L.

[0124] In some embodiments, when the ammonia nitrogen concentration is in the first judgment interval, the variable region is also used to adjust the dissolved oxygen concentration in the variable region to within the first preset interval so that the variable region provides an anaerobic environment for the microorganisms in the variable region.

[0125] In some embodiments, when the ammonia nitrogen concentration is in the second judgment interval, the variable region is also used to adjust the dissolved oxygen concentration in the variable region to a second preset interval so that the variable region provides a micro-oxygen environment for the microorganisms in the variable region.

[0126] In some embodiments, when the ammonia nitrogen concentration is in the third judgment interval, the variable region is also used to adjust the dissolved oxygen concentration in the variable region to the third preset interval so that the variable region provides an aerobic environment for the microorganisms in the variable region.

[0127] In some embodiments, the second monitor is connected to the first monitor and the second aeration device, respectively, and the second monitor is also used to obtain the dissolved oxygen concentration in the variable zone and the monitoring index data of the water in the aerobic zone monitored by the first monitor, and adjust the operating state of the second aeration device according to the dissolved oxygen concentration in the variable zone and the monitoring index data of the water in the aerobic zone to adjust the dissolved oxygen concentration in the variable zone to a preset interval corresponding to the target judgment interval. For example, when it is necessary to increase the dissolved oxygen concentration in the variable zone, the aeration intensity of the second aeration device is increased to inject more oxygen into the variable zone. When it is necessary to reduce the dissolved oxygen concentration in the variable zone, the aeration intensity of the second aeration device is reduced or the second aeration device is turned off.

[0128] Optionally, the second monitor is also connected to the second stirring device, and the second monitor is also used to adjust the operating state of the second stirring device according to the monitoring index data of the dissolved oxygen concentration in the variable zone and the water in the aerobic zone. For example, when the dissolved oxygen concentration in the variable zone is increased, the stirring speed of the second stirring device is reduced or the second stirring device is turned off; when the dissolved oxygen concentration in the variable zone is reduced, the stirring speed of the second stirring device is increased.

[0129] In some embodiments, the second stirring device is turned off in an aerobic environment. In an aerobic environment, the aeration intensity of the second aeration device is high, and the airflow can stir the mud-water mixture to make the mud-water mixture in a suspension state, so the second stirring device does not need to be turned on. By turning off the second stirring device in an aerobic environment, energy consumption can be further reduced.

[0130] In some embodiments, in the micro-oxygen environment, the stirring speed of the second stirring device is reduced so that the stirring speed of the second stirring device is lower than the normal speed. In this way, energy consumption can be further reduced.

[0131] In some embodiments, in the anoxic environment, the stirring speed of the second stirring device is set at a normal speed.

[0132] In some embodiments, the variable region is further provided with a second control device.

[0133] In some embodiments, the second control device is connected to the first monitor, the second monitor, and the second aeration device, respectively. The second control device is used to obtain the monitoring index data of the water in the aerobic zone monitored by the first monitor and the dissolved oxygen concentration in the variable zone monitored by the second monitor, and adjust the operating state of the second aeration device according to the dissolved oxygen concentration in the variable zone and the monitoring index data of the water in the aerobic zone to adjust the dissolved oxygen concentration in the variable zone to within a preset interval corresponding to the target judgment interval.

[0134] In some embodiments, the second control device is also connected to the second stirring device, and the second control device is further used to adjust the operating state of the second stirring device according to the monitoring index data of the dissolved oxygen concentration in the variable zone and the water in the aerobic zone.

[0135] In some embodiments, the first monitor is connected to the second aeration device, and the first monitor is further used to adjust the operating state of the second aeration device according to the monitoring index data of the water in the aerobic zone.

[0136] In some embodiments, a preset interval of dissolved oxygen concentration in a variable zone corresponds to a preset operating state of the second aeration device.

[0137] In some embodiments, the first monitor is used to determine a preset interval based on monitoring index data of water in the aerobic zone, and control the second aeration device to be in a preset operating state corresponding to the preset interval to control the dissolved oxygen concentration in the variable zone.

[0138] Optionally, the correspondence between the preset interval of dissolved oxygen concentration in the variable zone and the preset operating state of the second aeration device is determined by experiment.

[0139] In some embodiments, the first monitor is connected to the second monitor and the second aeration device, respectively. The first monitor is also used to obtain the dissolved oxygen concentration of the variable zone monitored by the second monitor, and adjust the operating state of the second aeration device according to the monitoring index data of the dissolved oxygen concentration in the variable zone and the water in the aerobic zone.

[0140] In some embodiments, the first monitor is also connected to the second stirring device, and the first monitor is further used to adjust the operating state of the second stirring device according to the monitoring index data of the dissolved oxygen concentration in the variable zone and the water in the aerobic zone.

[0141] In some embodiments, the water treatment system is provided with a general control device, which is used to connect to all devices in the water treatment system respectively, obtain the monitoring data and / or operating status sent by each device, and control each device according to the monitoring data and / or operating status sent by each device.

[0142] In some embodiments, the user adjusts the operating state of the second aeration device according to the dissolved oxygen concentration in the variable zone and the monitoring index data of the water in the aerobic zone to control the dissolved oxygen concentration in the variable zone.

[0143] In some embodiments, the user adjusts the operating state of the second aeration device according to the monitoring indicator data of the water in the aerobic zone to control the dissolved oxygen concentration in the variable zone.

[0144] In some embodiments, the user determines a preset interval according to monitoring index data of water in the aerobic zone, and controls the second aeration device to be in a preset operating state corresponding to the preset interval to control the dissolved oxygen concentration in the variable zone.

[0145] In some embodiments, the residence time of water in the variable zone is 1 h to 2 h.

[0146] In some embodiments, the sludge concentration in the variable zone is 3500 mg / L to 5500 mg / L.

[0147] like Figure 1 As shown, in some embodiments, the muddy-water mixture flowing out of the variable zone 130 flows into the anoxic zone 140 .

[0148] In some embodiments, the anoxic zone is used to provide an anoxic environment so that the microorganisms in the anoxic zone use the muddy water mixture in the anoxic zone to perform endogenous denitrification reaction. In this way, the water treatment system can maintain high standard of effluent quality without adding external carbon source.

[0149] In some embodiments, the endogenous denitrification rate in the anoxic zone can reach 0.5 mgN / (gVSS.h)-0.85 mgN / (gVSS.h), where mgN represents milligrams of nitrogen, gVSS represents grams of volatile suspended solids (VSS), VSS refers to the organic matter content in the sludge during the water treatment process, and h represents hours.

[0150] like Figure 1 As shown, in some embodiments, the anoxic zone 140 is provided with a third stirring device 141, and the third stirring device 141 is used to make the mud-water mixture in the anoxic zone 140 in a suspension state.

[0151] In some embodiments, the residence time of water in the anoxic zone is from 5 h to 8 h.

[0152] In some embodiments, the sludge concentration in the anoxic zone is 4000 mg / L to 6000 mg / L.

[0153] like Figure 1 As shown, in some embodiments, a first return pipe 170 is provided between the anaerobic zone 110 and the anoxic zone 140, and a first return pump 171 is provided in the first return pipe 170. The first return pump 171 is used to pump the muddy water mixture in the anoxic zone 140 into the anaerobic zone 110 through the first return pipe 170. The muddy water mixture in the anoxic zone 140 includes microorganisms in the anoxic zone 140. In this way, the total amount of microorganisms in the anaerobic environment can be kept stable, which is conducive to fully treating water using the microorganisms in the anaerobic environment.

[0154] In some embodiments, the first reflux ratio corresponding to the first reflux pipe is 100% to 200%. The first reflux ratio is the value of the amount of water refluxed in the first reflux pipe divided by the amount of water inlet.

[0155] like Figure 1 As shown, in some embodiments, the volume ratio of the anaerobic zone 110, the aerobic zone 120, the variable zone 130, and the anoxic zone 140 is 2:2:1:4.

[0156] like Figure 1 As shown, in some embodiments, the muddy water mixture flowing out of the anoxic zone 140 flows into the membrane bioreactor 150. The membrane bioreactor (MBR) may also be referred to as an MBR tank.

[0157] In some embodiments, the membrane bioreactor is used to perform solid-liquid separation on the mud-water mixture in the membrane bioreactor to obtain treated water. By using the membrane bioreactor to perform solid-liquid separation on the mud-water mixture in the membrane bioreactor, the conventional secondary sedimentation tank can be omitted, so that the water treatment system occupies a small area, thereby saving engineering investment costs, and making the water treatment system suitable for new construction and renovation and expansion projects of water purification plants in high-density urban areas.

[0158] like Figure 1 As shown, in some embodiments, the membrane biological reactor 150 is provided with a membrane assembly 151 , and the membrane assembly 151 is used to perform solid-liquid separation treatment on the mud-water mixture in the membrane biological reactor 150 .

[0159] In some embodiments, the membrane assembly is cleaned offline, that is, the membrane assembly is removed from the membrane bioreactor tank for cleaning.

[0160] In some embodiments, the membrane assembly is cleaned with a sodium hypochlorite solution 1-2 times a week, and each cleaning time is 30 minutes.

[0161] like Figure 1 As shown, in some embodiments, the membrane biological reactor 150 is provided with a third aeration device 161 , which is used to drive water to flush the membrane assembly 151 in the membrane biological reactor 150 through airflow to reduce solids attached to the membrane assembly 151 .

[0162] In some embodiments, the third aeration device is also used to make the mud-water mixture in the membrane biological reactor tank in a suspension state. In this way, the microorganisms in the membrane biological reactor tank can fully treat the water.

[0163] In some embodiments, the dissolved oxygen concentration in the membrane bioreactor is 3.5 mg / L to 6.0 mg / L.

[0164] In some embodiments, the sludge concentration in the membrane bioreactor is 6000 mg / L to 9000 mg / L.

[0165] like Figure 1As shown, in some embodiments, a second reflux pipe 180 is provided between the aerobic zone 120 and the membrane biological reactor 150, and a second reflux pump 181 is provided in the second reflux pipe 180. The second reflux pump 181 is used to pump the muddy water mixture of the membrane biological reactor 150 into the aerobic zone 120 through the second reflux pipe 180. The muddy water mixture of the membrane biological reactor 150 includes microorganisms in the membrane biological reactor 150. In this way, the total amount of microorganisms in the aerobic environment can be kept stable, which is conducive to fully treating the water using the microorganisms in the aerobic environment. In addition, since the dissolved oxygen concentration of the muddy water mixture in the membrane biological reactor is high, the aeration energy consumption of the aerobic zone can also be reduced.

[0166] In some embodiments, the second reflux ratio corresponding to the second reflux pipe is 200% to 400%. The second reflux ratio is the value of the amount of water refluxed in the second reflux pipe divided by the amount of water inlet.

[0167] In summary, the water treatment system provided by the embodiment of the present application has the following advantages:

[0168] 1. The water to be treated flows through the anaerobic zone, aerobic zone, variable zone, anoxic zone and membrane biological reactor in sequence. The anoxic zone is placed after the aerobic zone. The water treatment system does not need to reflux the nitrification liquid, which saves a lot of operating energy consumption. The variable zone is also used to adjust the dissolved oxygen concentration in the variable zone to the preset interval corresponding to the target judgment interval according to the target judgment interval, so as to provide anoxic environment, microoxic environment or aerobic environment for the microorganisms in the variable zone, thereby adjusting the main reaction of the microorganisms in the variable zone, realizing efficient utilization of dissolved oxygen in water, thereby reducing aeration energy consumption, thereby reducing the total energy consumption of the water treatment system, and at the same time improving the sewage treatment effect.

[0169] 2. By providing a semi-soft filler in the aerobic zone, the sludge in the aerobic zone can be easily attached to the semi-soft filler, thereby increasing the total amount of microorganisms in the aerobic zone and improving the efficiency of sewage treatment using microorganisms in the aerobic zone. Compared with conventional sewage treatment methods such as AAO, it can save about half of the aerobic zone volume, thereby reducing the aeration energy consumption of the aerobic zone. In addition, the structural form of the semi-soft filler will create a certain range of anoxic environment in the aerobic zone, which can strengthen the simultaneous nitrification and denitrification reaction in the aerobic zone.

[0170] 3. Through the endogenous denitrification reaction mainly carried out by microorganisms in the anoxic zone, the water treatment system can maintain high standards of effluent quality without the need to add external carbon sources.

[0171] 4. By using a membrane bioreactor to separate the mud and water mixture in the membrane bioreactor for solid-liquid separation, the conventional secondary sedimentation tank can be eliminated, so that the water treatment system occupies a small area, thereby saving project investment costs and making the water treatment system suitable for the construction and expansion of water purification plants in high-density urban areas.

[0172] 5. By providing a second reflux pipe between the aerobic zone and the membrane bioreactor, the total amount of microorganisms in the aerobic environment can be kept stable, which is conducive to fully treating the water using the microorganisms in the aerobic environment. In addition, since the dissolved oxygen concentration of the mud-water mixture in the membrane bioreactor is high, the aeration energy consumption of the aerobic zone can also be reduced.

[0173] The present application also provides a water treatment method, which is applied to the water treatment system as described above.

[0174] See also Figure 2 , Figure 2 Schematic diagram of the water treatment method provided in the embodiment of the present application. Figure 2 As shown, the water treatment method includes: step S100 to step S500.

[0175] Step S100: injecting water to be treated into the anaerobic zone for treatment.

[0176] In some embodiments, the anaerobic zone is used to provide an anaerobic environment so that the microorganisms in the anaerobic zone can release phosphorus and synthesize intracellular carbon sources using organic matter in the water to be treated.

[0177] The content of step S100 refers to the above related description.

[0178] Step S200: injecting the mud-water mixture at the end of the anaerobic zone into the aerobic zone for treatment.

[0179] In some embodiments, the aerobic zone is used to provide an aerobic environment so that the microorganisms in the aerobic zone can utilize the muddy water mixture in the aerobic zone to perform aerobic phosphorus absorption reaction, nitrification reaction and simultaneous nitrification and denitrification reaction.

[0180] The content of step S200 refers to the above related description.

[0181] Step S300: injecting the mud-water mixture at the end of the aerobic zone into the variable zone for treatment.

[0182] In some embodiments, the variable area is used to determine the target judgment interval in which the monitoring indicator data is located based on the monitoring indicator data of the water and a plurality of judgment intervals, wherein each judgment interval corresponds to a preset interval of dissolved oxygen concentration.

[0183] In some embodiments, the variable region is also used to adjust the dissolved oxygen concentration in the variable region to a preset range corresponding to the target judgment range according to the target judgment range, so as to provide an anoxic environment, a microoxic environment or an aerobic environment for the microorganisms in the variable region, thereby regulating the main reaction of the microorganisms in the variable region.

[0184] The content of step S300 refers to the above related description.

[0185] In some embodiments, the monitoring indicator data includes the ammonia nitrogen concentration of the water at the end of the aerobic zone.

[0186] In some implementations, the plurality of judgment intervals include a first judgment interval, a second judgment interval, and a third judgment interval, the first judgment interval corresponds to a first preset interval, the second judgment interval corresponds to a second preset interval, and the third judgment interval corresponds to a third preset interval.

[0187] See also Figure 3 , Figure 3 yes Figure 2 Detailed flow chart of step S300 in FIG. Figure 3 As shown, in some embodiments, step S300 includes steps S310 to S340.

[0188] Step S310: injecting the mud-water mixture at the end of the aerobic zone into the variable zone.

[0189] Step S320: When the ammonia nitrogen concentration is in the first judgment interval, the dissolved oxygen concentration in the variable zone is adjusted to within the first preset interval, so that the variable zone provides an anoxic environment for the microorganisms in the variable zone.

[0190] Step S330: When the ammonia nitrogen concentration is in the second judgment interval, the dissolved oxygen concentration in the variable zone is adjusted to the second preset interval so that the variable zone provides a micro-oxygen environment for the microorganisms in the variable zone.

[0191] Step S340: When the ammonia nitrogen concentration is in the third judgment interval, the dissolved oxygen concentration in the variable zone is adjusted to the third preset interval so that the variable zone provides an aerobic environment for the microorganisms in the variable zone.

[0192] The contents of step S310 to step S340 refer to the above related description.

[0193] Step S400: injecting the mud-water mixture at the end of the variable zone into the anoxic zone for treatment.

[0194] In some embodiments, the anoxic zone is used to provide an anoxic environment so that microorganisms in the anoxic zone can perform endogenous denitrification using the muddy water mixture in the anoxic zone.

[0195] The content of step S400 refers to the above related description.

[0196] Step S500: injecting the mud-water mixture at the end of the anoxic zone into the membrane biological reaction tank for solid-liquid separation treatment to obtain treated water.

[0197] The content of step S500 refers to the above related description.

[0198] In order to verify the water treatment system of the present application and the water treatment method applied to the water treatment system, the inventor conducted an experiment. The following is some description of the experiment.

[0199] This experiment was conducted in a water purification plant in Shenzhen. The total design scale of the water purification plant is 400,000 m 3 / d, the sewage treatment process is: coarse screen + lifting pump fine screen and aerated grit chamber + rapid sedimentation tank + fine screen + BNR biological reactor + MBR tank + ultraviolet disinfection + effluent. The design scale of this experiment is 576L / d (liters per day), and the inlet water quality of the water treatment system is the same as that of the water purification plant, and its pretreatment facilities are used.

[0200] The inlet COD concentration of the water purification plant is ≤550mg / L, the inlet ammonia nitrogen concentration is ≤35mg / L, the inlet TN concentration is ≤42mg / L, and the inlet TP concentration is ≤5.6mg / L; the outlet COD concentration is ≤30mg / L, the outlet ammonia nitrogen concentration is ≤1.5mg / L, the outlet TN concentration is ≤15mg / L, and the outlet TP concentration is ≤0.3mg / L. The water treatment system of this experiment is used to treat the inlet water, and the outlet COD concentration is 15-25mg / L, the outlet ammonia nitrogen concentration is 0.2-1.2mg / L, the outlet TN concentration is 4-10mg / L, and the outlet TP concentration is 0.2-0.3mg / L. It can be seen that the water treatment system of this application is used to treat the inlet water, and the treatment effect meets the requirements of the plant area, and some indicators are better than the requirements of the plant. The water treatment system of the present application has high denitrification efficiency. Without adding an external carbon source, technical indicators such as effluent COD concentration, effluent ammonia nitrogen concentration, and effluent TN concentration all stably reach or even exceed the national Class A emission standards, and the effluent effect is higher than that of sewage treatment using the BNR+MBR process with the same influent water quality conditions in the plant area.

[0201] Influent TP concentration (Total Phosphorus Concentration) refers to the concentration of total phosphorus in the water to be treated during the sewage treatment process. Effluent TP concentration refers to the concentration of total phosphorus in the water after the sewage treatment process. Total phosphorus refers to the sum of phosphorus elements in the form of soluble phosphates (such as orthophosphate, hypophosphite), organic phosphorus and particulate phosphorus.

[0202] This experiment includes the following steps.

[0203] (1) Adjust the volume ratio of the anaerobic zone, aerobic zone, variable zone and anoxic zone in the water treatment system and verify the optimal residence time of each zone.

[0204] When the volume ratio of anaerobic zone: aerobic zone: variable zone: anoxic zone is 2:2:1:3, the average effluent concentration of ammonia nitrogen is 0.6±0.3 mg / L, and the average effluent concentration of TN is 8.5 mg / L±1 mg / L.

[0205] When the volume ratio of anaerobic zone: aerobic zone: variable zone: anoxic zone is 2:2:1:4, the average concentration of ammonia nitrogen in effluent is 0.45mg / L±0.3mg / L, and the average concentration of TN in effluent is 6mg / L±0.5mg / L. Therefore, increasing the volume ratio of anoxic zone and extending the residence time of anoxic zone can effectively improve the denitrification effect of the system. When the volume ratio of anaerobic zone: aerobic zone: variable zone: anoxic zone is 2:2:1:4, it is considered to be a more ideal water treatment system zoning form.

[0206] (2) On the basis of a volume ratio of 2:2:1:4 for the anaerobic zone: aerobic zone: variable zone: anoxic zone, the inlet flow rate was gradually increased and the inlet load was controlled at 460 L / d (load 80%), 576 L / d (load 100%) and 690 L / d (load 120%), respectively, to investigate the optimal load range of the water treatment system.

[0207] The results show that when the inlet load is 80%, the average concentration of ammonia nitrogen in the effluent is 0.50mg / L±0.2mg / L, and the average concentration of TN in the effluent is 5.0mg / L±0.5mg / L. When the inlet load is 100%, the average concentration of ammonia nitrogen in the effluent is 0.50mg / L±0.2mg / L, and the average concentration of TN in the effluent is 6mg / L±1.5mg / L. When the inlet load is 120%, the average concentration of ammonia nitrogen in the effluent is 0.7mg / L±0.5mg / L, and the average concentration of TN in the effluent is 9mg / L±1mg / L. Therefore, in order to achieve high denitrification efficiency, the inlet load range of 80%-120% can guarantee a good effluent effect.

[0208] (3) Optimize the second reflux ratio and control the reflux ratio to 200%-300% and 300-400% in the design parameter range, and investigate the effect of the second reflux ratio on the denitrification effect of the system.

[0209] Experiments show that when the second reflow ratio is 200%-300%, the sludge concentration in the aerobic zone is 4200±400mg / L, and the sludge concentration in the anoxic zone is 4500±300mg / L. At this time, the average TN concentration of the effluent is 6.5±1.0mg / L. When the second reflow ratio is 300-400%, the sludge concentration in the aerobic zone is 4800±500mg / L, and the sludge concentration in the anoxic zone is 5000±300mg / L. At this time, the average TN concentration of the effluent is 5.0±0.8mg / L. Therefore, the second reflow ratio directly affects the sludge concentration of the system. When the second reflow ratio is low, the sludge concentration of the system decreases, which in turn affects the sludge load of the MBR pool; when the second reflow ratio is large, the denitrification effect of the system can be effectively improved. In general, considering the operating energy consumption and treatment effect, the ideal second reflow ratio is 200%-250%.

[0210] (4) Optimize the first reflux ratio. Control the first reflux ratio to 100%-150% and 150%-200% in the design parameter range, and investigate the effect of the first reflux ratio on the denitrification effect of the system.

[0211] Experiments show that when the first reflow ratio is 100%-150%, the sludge concentration in the anaerobic zone is 4200±300mg / L, the sludge concentration in the aerobic zone is 4400±500mg / L, and the sludge concentration in the anoxic zone is 4500±600mg / L. At this time, the average TN concentration of the effluent is 5.5±0.8mg / L. When the first reflow ratio is 150%-200%, the sludge concentration in the anaerobic zone is 4300±300mg / L, the sludge concentration in the aerobic zone is 4500±300mg / L, and the sludge concentration in the anoxic zone is 4300±500mg / L. At this time, the average TN concentration of the effluent is 5.0±0.5mg / L. It can be seen that the first reflow ratio has little effect on the denitrification effect of the system. In order to reduce the operating energy consumption of the water purification plant, the ideal first reflow ratio is 100%-150%.

[0212] (5) Flexibly adjust the dissolved oxygen concentration in the aerobic zone and the variable zone.

[0213] The first monitor controls the dissolved oxygen concentration in the aerobic zone to be 1.5mg / L-4mg / L:

[0214] a) When the influent TN concentration is greater than or equal to 80 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 10 mg / L, the dissolved oxygen concentration in the aerobic zone is controlled to be 3.5 mg / L to 4 mg / L.

[0215] b) When the inlet TN concentration is greater than or equal to 50 mg / L and less than 80 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 6 mg / L and less than 10 mg / L, the dissolved oxygen concentration in the aerobic zone is controlled to be 2.5 mg / L to 3.5 mg / L.

[0216] c) When the inlet TN concentration is greater than or equal to 30 mg / L and less than 50 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 3 mg / L and less than 6 mg / L, the dissolved oxygen concentration in the aerobic zone is controlled to be 2 mg / L to 2.5 mg / L.

[0217] d) When the inlet TN concentration is less than 30 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is less than 3 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration in the aerobic zone to 1.5 mg / L to 2 mg / L.

[0218] The variable zone is also provided with a second stirring device and a second aeration device to provide anoxic environment, micro-oxic environment or aerobic environment for the microorganisms in the variable zone.

[0219] The first monitor set in the aerobic zone controls the dissolved oxygen concentration in the variable zone to be 0.5mg / L-2mg / L:

[0220] a) When the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 3 mg / L, the dissolved oxygen concentration in the variable zone is controlled to be 1.5 mg / L-2 mg / L. At this time, the variable zone provides an aerobic environment for the microorganisms in the variable zone, and the microorganisms further carry out nitrification reaction.

[0221] b) When the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 1 mg / L and less than 3 mg / L, the dissolved oxygen in the variable zone is controlled to be 1 mg / L-1.5 mg / L. At this time, the variable zone provides a micro-aerobic environment for the microorganisms in the variable zone, and the microorganisms carry out simultaneous nitrification and denitrification reactions while carrying out nitrification reactions.

[0222] c) When the ammonia nitrogen concentration of the water at the end of the aerobic zone is less than 1 mg / L, the second aeration device of the variable zone is closed to form an anoxic environment in the variable zone. At this time, the microorganisms in the variable zone mainly carry out endogenous denitrification reaction.

[0223] In summary, the present application provides a water treatment system and a water treatment method, wherein the water treatment system is composed of an anaerobic zone, an aerobic zone, a variable zone, an anoxic zone and a membrane bioreactor tank connected in sequence, and the water to be treated flows through the anaerobic zone, the aerobic zone, the variable zone, the anoxic zone and the membrane bioreactor tank in sequence; the anaerobic zone is used to provide an anaerobic environment so that the microorganisms in the anaerobic zone can release phosphorus and synthesize an intracellular carbon source using organic matter in the water to be treated; the aerobic zone is used to provide an aerobic environment so that the microorganisms in the aerobic zone can use the mud-water mixture in the aerobic zone to perform aerobic phosphorus absorption reaction, nitrification reaction and simultaneous nitrification and denitrification reaction; the variable zone is used to monitor the water according to the water monitoring index data and multiple judgments. The variable zone is used to determine the target judgment interval in which the monitoring index data is located, wherein each judgment interval corresponds to a preset interval of dissolved oxygen concentration; the variable zone is also used to adjust the dissolved oxygen concentration in the variable zone to the preset interval corresponding to the target judgment interval according to the target judgment interval, so as to provide anoxic environment, microoxic environment or aerobic environment for the microorganisms in the variable zone, thereby adjusting the main reaction of the microorganisms in the variable zone; the anoxic zone is used to provide anoxic environment so that the microorganisms in the anoxic zone can utilize the mud-water mixture in the anoxic zone to carry out endogenous denitrification reaction; the membrane bioreactor is used to perform solid-liquid separation treatment on the mud-water mixture in the membrane bioreactor to obtain treated water. In the present application, the water to be treated flows through the anaerobic zone, the aerobic zone, the variable zone, the anoxic zone and the membrane biological reactor in sequence. The anoxic zone is placed after the aerobic zone. The water treatment system does not need to reflux the nitrification liquid, which saves a lot of operating energy consumption. The variable zone is also used to adjust the dissolved oxygen concentration in the variable zone to a preset interval corresponding to the target judgment interval according to the target judgment interval, so as to provide an anoxic environment, a microoxic environment or an aerobic environment for the microorganisms in the variable zone, thereby adjusting the main reactions of the microorganisms in the variable zone, and realizing efficient utilization of dissolved oxygen in the water, thereby reducing aeration energy consumption, thereby reducing the total energy consumption of the water treatment system, and at the same time improving the sewage treatment effect.

[0224] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A water treatment system, characterized in that: The water treatment system is formed by sequentially connecting an anaerobic zone, an aerobic zone, a variable zone, an anoxic zone and a membrane bioreactor, and the water to be treated flows through the anaerobic zone, the aerobic zone, the variable zone, the anoxic zone and the membrane bioreactor in sequence; The anaerobic zone is used to provide an anaerobic environment so that the microorganisms in the anaerobic zone can release phosphorus and synthesize intracellular carbon sources using organic matter in the water to be treated; The aerobic zone is used to provide an aerobic environment so that the microorganisms in the aerobic zone can utilize the mud-water mixture in the aerobic zone to perform aerobic phosphorus absorption reaction, nitrification reaction and simultaneous nitrification and denitrification reaction; The aerobic zone is provided with a semi-soft filler, which is used to increase the number of microorganisms in the aerobic zone. The semi-soft filler is suspended in the aerobic zone through a bracket, and has a structure that facilitates the attachment of microorganisms in the aerobic zone. The filling rate of the semi-soft filler is 80% to 90%, and the specific surface area of ​​the semi-soft filler is 80m 2 / m 3 Up to 120m 2 / m 3 ; The variable area is used to determine the target judgment interval in which the monitoring index data is located according to the water monitoring index data and a plurality of judgment intervals, wherein each of the judgment intervals corresponds to a preset interval of dissolved oxygen concentration; The variable region is also used to adjust the dissolved oxygen concentration of the variable region to a preset range corresponding to the target judgment range according to the target judgment range, so as to provide an anoxic environment, a microoxic environment or an aerobic environment for the microorganisms in the variable region, thereby adjusting the reaction mainly performed by the microorganisms in the variable region; The monitoring index data includes the ammonia nitrogen concentration of the water at the end of the aerobic zone, the multiple judgment intervals include a first judgment interval, a second judgment interval and a third judgment interval, the first judgment interval corresponds to a first preset interval, the second judgment interval corresponds to a second preset interval, and the third judgment interval corresponds to a third preset interval; When the ammonia nitrogen concentration is in the first judgment interval, the variable region is further used to adjust the dissolved oxygen concentration in the variable region to within the first preset interval, so that the variable region provides the anoxic environment for the microorganisms in the variable region; When the ammonia nitrogen concentration is in the second judgment interval, the variable region is further used to adjust the dissolved oxygen concentration in the variable region to the second preset interval, so that the variable region provides the micro-aerobic environment for the microorganisms in the variable region; When the ammonia nitrogen concentration is in the third judgment interval, the variable region is also used to adjust the dissolved oxygen concentration of the variable region to the third preset interval, so that the variable region provides the aerobic environment for the microorganisms in the variable region; the first judgment interval is that the ammonia nitrogen concentration is less than 1 mg / L, the second judgment interval is that the ammonia nitrogen concentration is greater than or equal to 1 mg / L and less than 3 mg / L, the third judgment interval is that the ammonia nitrogen concentration is greater than or equal to 3 mg / L, the first preset interval is that the dissolved oxygen concentration of the variable region is less than 0.5 mg / L, the second preset interval is that the dissolved oxygen concentration of the variable region is greater than or equal to 1 mg / L and less than 1.5 mg / L, and the third preset interval is that the dissolved oxygen concentration of the variable region is greater than or equal to 1.5 mg / L and less than or equal to 2 mg / L; The anoxic zone is used to provide an anoxic environment so that the microorganisms in the anoxic zone can use the mud-water mixture in the anoxic zone to perform endogenous denitrification reaction; The membrane biological reaction tank is used to perform solid-liquid separation treatment on the mud-water mixture in the membrane biological reaction tank to obtain treated water; A first reflux pipeline is provided between the anaerobic zone and the anoxic zone, and a first reflux pump is provided in the first reflux pipeline, and the first reflux pump is used to pump the muddy-water mixture in the anoxic zone into the anaerobic zone through the first reflux pipeline, wherein the muddy-water mixture in the anoxic zone includes microorganisms in the anoxic zone, and the redox potential of the anaerobic zone is -200mV to -300mV; A second reflux pipeline is provided between the aerobic zone and the membrane biological reaction tank, and a second reflux pump is provided in the second reflux pipeline, and the second reflux pump is used to pump the muddy-water mixture of the membrane biological reaction tank into the aerobic zone through the second reflux pipeline, wherein the muddy-water mixture of the membrane biological reaction tank includes the microorganisms in the membrane biological reaction tank; The first reflux ratio corresponding to the first reflux pipeline is 100% to 200%, and the second reflux ratio corresponding to the second reflux pipeline is 200% to 400%; The residence time of water in the anaerobic zone is 2 to 4 hours, and the residence time of water in the aerobic zone is 2 to 4 hours; The volume ratio of the anaerobic zone, the aerobic zone, the variable zone and the anoxic zone is 2:2:1:

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2. The water treatment system according to claim 1, characterized in that: The anaerobic zone is provided with a first stirring device, and the first stirring device is used to make the mud-water mixture in the anaerobic zone in a suspension state; The aerobic zone is provided with a first aeration device and a first monitoring instrument, wherein the first aeration device is used to increase the dissolved oxygen concentration in the aerobic zone, and the first monitoring instrument is used to obtain monitoring index data of water in the aerobic zone; The variable zone is provided with a second stirring device, a second aeration device and a second monitoring instrument, the second stirring device is used to make the mud-water mixture in the variable zone in a suspension state, the second aeration device is used to increase the dissolved oxygen concentration in the variable zone, and the second monitoring instrument is used to monitor the dissolved oxygen concentration in the variable zone; The anoxic zone is provided with a third stirring device, and the third stirring device is used to make the mud-water mixture in the anoxic zone in a suspension state; The membrane biological reaction tank is provided with a third aeration device, and the third aeration device is used to drive water to flush the membrane components in the membrane biological reaction tank through airflow, so as to reduce solids attached to the membrane components.

3. The water treatment system according to any one of claims 1 to 2, characterized in that: When the influent TN concentration is greater than or equal to 80 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 10 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration of the aerobic zone to be 3.5 mg / L to 4 mg / L; When the influent TN concentration is greater than or equal to 50 mg / L and less than 80 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 6 mg / L and less than 10 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration of the aerobic zone to be 2.5 mg / L to 3.5 mg / L; When the influent TN concentration is greater than or equal to 30 mg / L and less than 50 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is greater than or equal to 3 mg / L and less than 6 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration of the aerobic zone to be 2 mg / L to 2.5 mg / L; When the influent TN concentration is less than 30 mg / L or the ammonia nitrogen concentration of the water at the end of the aerobic zone is less than 3 mg / L, the aerobic zone is also used to control the dissolved oxygen concentration of the aerobic zone to be 1.5 mg / L to 2 mg / L; The sludge concentration in the aerobic zone is 3500 mg / L to 5500 mg / L; The sludge concentration in the anoxic zone is 4000 mg / L to 6000 mg / L; The dissolved oxygen concentration of the membrane biological reactor is 3.5 mg / L to 6.0 mg / L, and the sludge concentration of the membrane biological reactor is 6000 mg / L to 9000 mg / L.

4. A water treatment method, characterized in that: The water treatment method is applied to the water treatment system according to any one of claims 1 to 2, and the method comprises: Injecting the water to be treated into an anaerobic zone for treatment, wherein the anaerobic zone is used to provide an anaerobic environment so that the microorganisms in the anaerobic zone can release phosphorus and synthesize intracellular carbon sources using organic matter in the water to be treated; The mud-water mixture at the end of the anaerobic zone is injected into the aerobic zone for treatment, wherein the aerobic zone is used to provide an aerobic environment so that the microorganisms in the aerobic zone can utilize the mud-water mixture in the aerobic zone to perform aerobic phosphorus absorption reaction, nitrification reaction and simultaneous nitrification and denitrification reaction; The mud-water mixture at the end of the aerobic zone is injected into the variable zone for treatment, and the variable zone is used to determine the target judgment interval in which the monitoring index data is located according to the water monitoring index data and multiple judgment intervals, wherein each of the judgment intervals corresponds to a preset interval of dissolved oxygen concentration, and the variable zone is also used to adjust the dissolved oxygen concentration of the variable zone to the preset interval corresponding to the target judgment interval according to the target judgment interval, so as to provide an anoxic environment, a microoxic environment or an aerobic environment for the microorganisms in the variable zone, thereby adjusting the main reaction of the microorganisms in the variable zone; Injecting the muddy water mixture at the end of the variable zone into the anoxic zone for treatment, wherein the anoxic zone is used to provide an anoxic environment so that the microorganisms in the anoxic zone can use the muddy water mixture in the anoxic zone to perform endogenous denitrification reaction; The mud-water mixture at the end of the anoxic zone is injected into a membrane bioreactor for solid-liquid separation to obtain treated water.

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