Multistage A / O tank sewage treatment system and method capable of dynamically switching parallel / series mode

Abstract

The invention relates to a multi-stage A / O pool sewage treatment system capable of dynamically switching a parallel / series mode, which is characterized in that a 1 # first-stage A pool is communicated with a 1 # first-stage O pool, a 1 # first-stage lifting device is arranged in the 1 # first-stage O pool, a 1 # first-stage backflow valve and a 2 # first-stage backflow valve are arranged on a 1 # backflow channel, a 2 # first-stage A pool is communicated with a 2 # first-stage O pool, the 2 # first-stage O pool is communicated with a 2 # second-stage A pool through a 2 # first-stage water outlet valve, and a 2 # second-stage water outlet valve is arranged on a 2 # backflow channel; the first reflux channel is provided with a first-stage reflux valve and a first-stage reflux valve, the second-stage A tank is communicated with the second-stage O tank, the second-stage A tank is communicated with the second-stage O tank, the second-stage A tank is internally provided with a second-stage lifting device, the second reflux channel is provided with a first-stage reflux valve and a second-stage reflux valve, the first-stage O tank is communicated with the first-stage A tank through a first-stage water outlet valve, the first-stage A tank is communicated with the first-stage O tank, the second-stage lifting device is arranged in the second-stage O tank, and the first-stage lifting device is arranged in the first-stage O tank. Through structure optimization and intelligent regulation and control, efficient and stable treatment of complex industrial wastewater is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a multi-stage A / O tank sewage treatment system and method capable of dynamically switching between parallel / series modes, which is particularly suitable for the efficient treatment of highly toxic and high-ammonia nitrogen industrial wastewater. Background Art

[0002] Currently, a two-stage parallel A / O (anoxic / aerobic) tank process is widely used in industrial wastewater treatment. This process, which evenly distributes the influent load across two independently operated A / O tanks, is suitable for treating low-concentration wastewater with relatively stable water quality and quantity. However, this process suffers from significant drawbacks in practical applications: First, the parallel structure suffers from a short hydraulic retention time, resulting in incomplete nitrification / denitrification reactions and difficulty in efficiently removing high-concentration ammonia nitrogen. Second, toxic substances in the influent (such as hydrazines) directly enter the parallel tanks, lacking a buffering mechanism. This can easily lead to inhibition of microbial activity and system collapse (re-inoculation of sludge requires more than seven days). Furthermore, the traditional process uses fixed operating parameters (such as aeration rate and sludge return ratio) and is unable to dynamically adjust its structure to fluctuations in water quality and quantity, resulting in high energy consumption and poor adaptability. The core problem with existing technologies is that the rigid structure of the parallel A / O tanks cannot balance treatment efficiency and shock resistance, and the lack of intelligent control methods makes it difficult to meet the complex and changing needs of industrial wastewater treatment. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a multi-stage A / O pool sewage treatment system and method that can dynamically switch between parallel / series modes, aiming to solve the problems of poor impact resistance, low treatment efficiency and rigid operation mode of traditional A / O pool processes.

[0004] The technical solution of the present invention to solve the above technical problems is as follows:

[0005] A multi-stage A / O tank sewage treatment system with dynamic switching between parallel and series modes, including:

[0006] 1# Level A pool, 1# Level A pool is connected with 1# Level O pool, 1# Level O pool is provided with 1# Level 1 lifting device for lifting the mixed liquid into 1# reflux channel in 1# Level 1 buffer dilution area, 1# Level 1 reflux valve and 2# Level 1 reflux valve are provided in the areas corresponding to 1# Level A pool and 2# Level A pool, 2# Level A pool is connected with 2# Level 1 O pool, 2# Level 1 O pool is connected with 2# Level 2 A pool via 2# Level 1 outlet valve, 2# Level 2 A pool is connected with 2# Level 2 O pool, 2# Level 2 O pool is provided with 2# Level 2 lifting device for lifting the mixed liquid into 2# reflux channel in 2# Level 2 buffer dilution area, 2# Level 2 reflux channel is provided with 1# Level 2 reflux valve and 2# Level 2 reflux valve in the areas corresponding to 1# Level 2 A pool and 2# Level 2 A pool, The secondary reflux valve and the 2# secondary reflux valve, the 1# primary O tank is connected to the 1# secondary A tank via the 1# primary outlet valve, the 1# secondary A tank is connected to the 1# secondary O tank, the 2# primary buffer dilution area of ​​the 2# primary O tank is equipped with a 2# primary lifting device for lifting the mixed liquid into the 1# reflux channel, and the 1# secondary buffer dilution area of ​​the 1# secondary O tank is equipped with a 1# secondary lifting device for lifting the mixed liquid into the 2# reflux channel; the 1# flow sensor, 1# COD monitor and 1# ammonia nitrogen monitor are used to measure the flow rate, COD and ammonia nitrogen in the 1# primary A tank respectively, and the 2# flow sensor, 2# COD monitor and 2# ammonia nitrogen monitor are used to measure the flow rate, COD and ammonia nitrogen in the 2# primary A tank respectively.

[0007] On the basis of the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, 1# first-level lifting device, 2# first-level lifting device, 1# first-level reflux valve, 2# first-level reflux valve, 1# first-level water outlet valve, 2# first-level water outlet valve, 1# second-level lifting device, 2# second-level lifting device, 1# flow sensor, 1# COD monitor, 1# ammonia nitrogen monitor, 2# flow sensor, 2# COD monitor and 2# ammonia nitrogen monitor are electrically connected to the control unit respectively.

[0009] Furthermore, the multi-stage A / O pool sewage treatment system capable of dynamically switching between parallel and series modes further includes: a bacterial seed tank for releasing toxic-resistant nitrifying bacteria concentrate into the 1# primary O pool and the 2# primary O pool. The bacterial seed tank is electrically connected to the control unit. The dosage of the toxic-resistant nitrifying bacteria concentrate is 0.5g / m 3 ~1.0g / m 3 .

[0010] Furthermore, the 1# primary lifting device, the 1# secondary lifting device, the 2# primary lifting device and the 2# secondary lifting device all adopt gas lift devices.

[0011] Furthermore, a 1# secondary water outlet valve electrically connected to the control unit is provided on the pool wall of the 1# secondary O tank at the 1# secondary buffer dilution zone.

[0012] Furthermore, a 2# secondary water outlet valve electrically connected to the control unit is provided on the pool wall of the 2# secondary O tank at the 2# secondary buffer dilution zone.

[0013] Based on the above technical solution, the present invention also provides a multi-stage A / O pool sewage treatment method capable of dynamically switching between parallel and series modes, which uses the above multi-stage A / O pool sewage treatment system capable of dynamically switching between parallel and series modes, comprising the following steps:

[0014] S10, wastewater flows into the 1# primary A pool and the 2# primary A pool of the primary A / O pool module;

[0015] If the ammonia nitrogen concentration is ≤30mg / L, the COD instantaneous load is ≤500mg / L, and the flow fluctuation is <20%, the sludge in the secondary sedimentation tank will be returned to the 1# primary A tank and the 2# primary A tank, and the sludge in the secondary sedimentation tank will be returned to the 1# secondary A tank and the 2# secondary A tank, and the sludge return ratio will be fixed at 50% to 100%;

[0016] Denitrifying bacteria use organic matter in the influent as a carbon source to reduce nitrate in the return sludge to nitrogen gas, achieving preliminary denitrification. Nitrifying bacteria oxidize ammonia nitrogen to nitrate and degrade COD at the same time. The aeration rate is automatically adjusted based on the feedback from the DO sensor to maintain the dissolved oxygen in the O tank. The effluent from the 1# secondary O tank and the 2# secondary O tank is collected into the public secondary sedimentation tank. After mud and water separation, the supernatant enters the subsequent treatment unit. If any of the following conditions are met: ammonia nitrogen concentration > 100 mg / L, COD instantaneous load > 1000 mg / L, flow fluctuation > 20%, or toxic substances are detected, the switching condition is triggered and the process enters S20.

[0017] S20, sending a switching instruction to the valve group and the lifting device to allow the primary A / O pool module and the secondary A / O pool module to operate in series;

[0018] Valve group adjustment: Close the 1# first-level water outlet valve and the 2# second-level water outlet valve, and open the 2# first-level return valve and the 1# second-level return valve;

[0019] Lifting device adjustment:

[0020] Start the 1# first-level lifting device to mix the effluent from the 1# first-level O tank with the return sludge and then send it into the 2# first-level A tank through the 1# return channel and the 2# first-level return valve;

[0021] Start the 2# secondary lifting device to mix the effluent from the 2# secondary O tank with the return sludge and then send it into the 1# secondary A tank through the 2# return channel and the 1# secondary return valve;

[0022] Four-stage A / O series operation:

[0023] First-stage A / O: Initially degrades COD and ammonia nitrogen. The mixed liquid in the 1# primary O pool is sent to the 2# primary A pool via the 1# primary lifting device through the 1# return channel and the 2# primary return valve. Then, the effluent from the 2# primary O pool enters the 2# secondary A pool via the 2# primary outlet valve.

[0024] The third stage A / O: further nitrification and denitrification, using the 2# secondary lifting device to send the mixed liquid in the 2# secondary O pool through the 2# return channel and the 1# secondary return valve into the 1# secondary A pool to form a four-stage circulation.

[0025] Furthermore, in S10, the dissolved oxygen in the O tank is maintained at 2 mg / L to 3 mg / L.

[0026] Furthermore, the toxic substance in S20 is total hydrazine.

[0027] Furthermore, the total hydrazine concentration in S20 is >200 mg / L.

[0028] The beneficial effects of the present invention are:

[0029] 1) Switchable modular structure design: Breaking the fixed layout of traditional A / O tanks, two groups of two-stage A / O tanks are designed as independent modules. Through the combination of a multi-channel valve group (such as a pneumatic butterfly valve) and a lifting device, dynamic switching between parallel mode and four-stage series mode is achieved. In parallel mode, the two groups of A / O tanks operate independently, reducing energy consumption and maintenance burden; in series mode, the lifting device drives the front-stage effluent and sludge mixture into the rear-stage tank body, forming a four-stage circulation, extending the hydraulic retention time, and fully enhancing nitrification and denitrification reactions, especially for the deep degradation of high-concentration ammonia nitrogen (such as above 100 mg / L) and toxic substances (such as total hydrazine 200 mg / L);

[0030] 2) Stepped buffering process driven by lifting and reflux: In series mode, a mixing and dilution zone is set up at the outlet of each A / O tank. The effluent from the front stage is mixed with the sludge return liquid and transported to the back stage tank through a lifting device. At the same time, the stepped structure gradually dilutes toxic substances (such as hydrazines) in the influent. Combined with the adaptive domestication of the microbial community, the toxicity inhibition concentration threshold is increased by 50%, significantly enhancing system stability.

[0031] 3) Intelligent dynamic control strategy: Based on real-time monitoring data from ammonia nitrogen, COD, and flow sensors, the system automatically triggers mode switching and parameter adjustments. For example, when influent ammonia nitrogen is detected to be greater than 100 mg / L or flow fluctuation is greater than 20%, the system switches to series mode and simultaneously increases the sludge return ratio to 150% to 200%. Simultaneously, shock-resistant nitrifying bacteria pre-stored in the culture chamber are added. When water quality stabilizes (e.g., ammonia nitrogen ≤ 30 mg / L), the system automatically resumes parallel mode to reduce energy consumption. This strategy addresses the hysteresis problem of traditional processes that rely on manual intervention, achieving a "perception-decision-execution" closed-loop control system, ensuring rapid response and sustained stable operation of the system under complex operating conditions.

[0032] 4) Significantly improved treatment efficiency: In series mode, the four-stage A / O tank extends the hydraulic retention time through gas stripping reflux, strengthening the synergistic effect of nitrification and denitrification reactions. The ammonia nitrogen removal rate is increased from less than 60% in the traditional parallel system to over 95%, and the COD removal rate is stabilized at over 90%;

[0033] 5) Significantly enhanced shock resistance: The series structure forms a "stepped buffer pool" that effectively alleviates the transient inhibition of toxic substances (such as hydrazines) on microorganisms through the dual effects of gradual dilution and biodegradation, expands the tolerance concentration fluctuation range by 50%, and avoids the risk of system collapse;

[0034] 6) Reduced energy consumption and operation and maintenance costs: In parallel mode, aeration volume is reduced by 30% to 40% (only two independent groups need to be maintained). In series mode, the low-power design of gas lift reflux uses gas lift power to replace high-energy-consuming mechanical pumps. The energy consumption of the gas lift device is reduced by more than 50% compared to mechanical pumps, and the overall energy consumption is reduced by 15% compared to traditional four-stage series systems. At the same time, the intelligent control strategy can dynamically adjust the operation mode according to water quality, reducing waste caused by excessive aeration or chemical addition.

[0035] 7) Rapid recovery and high adaptability: The system has a built-in bacterial culture chamber that can automatically add toxic-resistant nitrifying bacteria concentrate when it is impacted. Combined with the dynamic adjustment of the sludge return ratio (increased to 150% to 200% in series mode), the recovery period is shortened from the traditional 7 days to 3 days. In addition, the modular design supports flexible switching of operating modes. It is suitable for highly toxic wastewater (such as hydrazine hydrate and pharmaceutical wastewater) and can also cope with seasonal water surges (such as flow fluctuations of ±50% in the rainy season), achieving efficient adaptation of "one machine for multiple scenarios". BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a structural diagram of the multi-stage A / O tank sewage treatment system that can dynamically switch between parallel / series modes in the present invention. DETAILED DESCRIPTION

[0037] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0038] Example 1

[0039] like Figure 1 As shown, the multi-stage A / O pool sewage treatment system that can dynamically switch between parallel and series modes includes:

[0040] 1# primary A pool 101, 1# primary A pool 101 is connected to 1# primary O pool 102, preferably 1# primary A pool 101 is connected to 1# primary O pool 102 by gravity, 1# primary buffer dilution zone 111 of 1# primary O pool 102 is provided with 1# primary lifting device 105 for lifting mixed liquid (effluent and sludge, the same below) into 1# return channel 113, that is, 1# primary lifting device 105 can lift the mixed liquid (effluent and sludge, the same below) in 1# primary O pool 102 into 1# return channel 113. The mixed liquid is drawn into the 1# return channel 113. The 1# return channel 113 is provided with a 1# first-level return valve 107 and a 2# first-level return valve 108 in the areas corresponding to the 1# first-level A pool 101 and the 2# first-level A pool 103, respectively. That is, when the 1# first-level return valve 107 is opened, the mixed liquid in the 1# return channel 113 can enter the 1# first-level A pool 101 through the 1# first-level return valve 107, and when the 1# first-level return valve 107 is closed, the mixed liquid in the 1# return channel 113 cannot be returned through the 1# first-level return valve 108. The valve 107 enters the 1# primary A pool 101, and the 2# primary reflux valve 108 is opened. The mixed liquid in the 1# reflux channel 113 can enter the 2# primary A pool 103 through the 2# primary reflux valve 108, while the 2# primary reflux valve 108 is closed. The mixed liquid in the 1# reflux channel 113 cannot enter the 2# primary A pool 103 through the 2# primary reflux valve 108. The 2# primary A pool 103 is connected to the 2# primary O pool 104. Preferably, the 2# primary A pool 103 is connected to the 2# primary O pool 104. 4. The 2# primary O2 tank 104 is connected to the 2# secondary A tank 203 via the 2# primary outlet valve 110 by gravity. When the 2# primary outlet valve 110 is opened, the wastewater in the 2# primary O2 tank 104 can flow into the 2# secondary A tank 203 via the 2# primary outlet valve 110. When the 2# primary outlet valve 110 is closed, the wastewater in the 2# primary O2 tank 104 cannot flow into the 2# secondary A tank 203 via the 2# primary outlet valve 110. The effluent from the 2# secondary O2 tank 204 is collected in the secondary sedimentation tank.

[0041] The 2# secondary A pool 203 is connected to the 2# secondary O pool 204, preferably the 2# secondary A pool 203 and the 2# secondary O pool 204 are connected by gravity. A 2# secondary lifting device 206 is arranged in the 2# secondary buffer dilution area 212 of the 2# secondary O pool 204 for lifting the mixed liquid into the 2# reflux channel 213, that is, the 2# secondary lifting device 206 can lift the mixed liquid in the 2# secondary buffer dilution area 212 of the 2# secondary O pool 204 into the 2# reflux channel 213. The 2# reflux channel 213 is provided with a 1# secondary reflux valve 207 and a 2# secondary reflux valve 207 in the areas corresponding to the 1# secondary A pool 201 and the 2# secondary A pool 203, respectively. 8, i.e., opening the 1# secondary reflux valve 207, the mixed liquid in the 2# reflux channel 213 can enter the 1# secondary A tank 201 through the 1# secondary reflux valve 207, while closing the 1# secondary reflux valve 207, the mixed liquid in the 2# reflux channel 213 cannot enter the 1# secondary A tank 201 through the 1# secondary reflux valve 207; opening the 2# secondary reflux valve 208, the mixed liquid in the 2# reflux channel 213 can enter the 2# secondary A tank 203 through the 2# secondary reflux valve 208, while closing the 2# secondary reflux valve 208, the mixed liquid in the 2# reflux channel 213 cannot enter the 2# secondary A tank 203 through the 2# secondary reflux valve 208;

[0042] 1# primary O pool 102 is connected to 1# secondary A pool 201 via 1# primary outlet valve 109. When 1# primary outlet valve 109 is opened, the wastewater in 1# primary O pool 102 can flow into 1# secondary A pool 201 via 1# primary outlet valve 109. When 1# primary outlet valve 109 is closed, the wastewater in 1# primary O pool 102 cannot flow into 1# secondary A pool 201 via 1# primary outlet valve 109. 1# secondary A pool 201 The effluent of the 1# secondary O2 pool 202 is connected to the 1# secondary O2 pool 202 by gravity, and the effluent of the 1# secondary O2 pool 202 is collected into the secondary sedimentation tank; the 2# primary buffer dilution area 112 of the 2# primary O2 pool 104 is provided with a 2# primary lifting device 106 for lifting the mixed liquid into the 1# return channel 113, that is, the 2# primary lifting device 106 can lift the 2# primary buffer dilution area 112 of the 2# primary O2 pool 104 into the 1# return channel 113. 2 is lifted into the 1# return channel 113; a 1# secondary lifting device 205 is arranged in the 1# secondary buffer dilution area 211 of the 1# secondary O pool 202 for lifting the mixed liquid into the 2# return channel 213, that is, the 1# secondary lifting device 205 can lift the mixed liquid in the 1# secondary buffer dilution area 211 of the 1# secondary O pool 202 into the 2# return channel 213, and the 1# flow sensor 301 is used to measure the flow rate in the 1# primary A pool 101. The flow rate, 1# COD monitor 303 is used to measure the COD value in 1# primary A pool 101, 1# ammonia nitrogen monitor 305 is used to measure the ammonia nitrogen value in 1# primary A pool 101, 2# flow sensor 302 is used to measure the flow in 2# primary A pool 103, 2# COD monitor 304 is used to measure the COD value in 2# primary A pool 103, 2# ammonia nitrogen monitor 306 is used to measure the ammonia nitrogen value in 2# primary A pool 103.

[0043] In this embodiment, 1# and 2# are numbers used only to distinguish A / O pools.

[0044] Example 2

[0045] like Figure 1 As shown, this embodiment is a further improvement on the basis of embodiment 1, specifically as follows:

[0046] 1# first-stage lifting device 105, 2# first-stage lifting device 106, 1# first-stage reflux valve 107, 2# first-stage reflux valve 108, 1# first-stage water outlet valve 109, 2# first-stage water outlet valve 110, 1# second-stage lifting device 205, 2# second-stage lifting device 206, 1# second-stage reflux valve 207, 2# second-stage reflux valve 208, 1# flow sensor 301, 1# COD monitor 303, 1# ammonia nitrogen monitor 305, 2# flow sensor 302, 2# COD monitor 304 and 2# ammonia nitrogen monitor 306 are electrically connected to the control unit 300, that is, 1# flow sensor 301, 1# COD monitor 303, 1# ammonia nitrogen monitor 305, 2# flow sensor 302, 2# COD monitor 304 and 2# ammonia nitrogen monitor 306 can feed back data to the control unit 300, and the control unit 300 can respectively control the actions of 1# first-level lifting device 105, 2# first-level lifting device 106, 1# first-level reflux valve 107, 2# first-level reflux valve 108, 1# first-level water outlet valve 109, 2# first-level water outlet valve 110, 1# second-level lifting device 205, 2# second-level lifting device 206, 1# second-level reflux valve 207, and 2# second-level reflux valve 208.

[0047] Example 3

[0048] like Figure 1 As shown, this embodiment is a further improvement on the basis of embodiment 1 or 2, specifically as follows:

[0049] The multi-stage A / O tank sewage treatment system capable of dynamically switching between parallel and series modes further includes: a bacterial seed tank 400 for releasing a toxic-resistant nitrifying bacteria concentrate into the 1# primary O tank 102 and the 2# primary O tank 104. The bacterial seed tank 400 is electrically connected to the control unit 300. The control unit 300 is used to control the bacterial seed tank 400 to automatically release the toxic-resistant nitrifying bacteria concentrate. The dosage of the toxic-resistant nitrifying bacteria concentrate is 0.5 g / m 3 ~1.0g / m 3 .

[0050] Example 4

[0051] like Figure 1 As shown, this embodiment is a further improvement on the basis of embodiment 1, 2 or 3, and the details are as follows:

[0052] The 1# first-stage lifting device 105 preferably adopts an air stripping device, the 1# second-stage lifting device 205 preferably adopts an air stripping device, the 2# first-stage lifting device 106 preferably adopts an air stripping device, and the 2# second-stage lifting device 206 preferably adopts an air stripping device. Of course, in actual application, the use of other devices is not excluded, such as: a pump. This is just an exemplary description.

[0053] Example 5

[0054] like Figure 1 As shown, this embodiment is a further improvement on the basis of any one of the embodiments 1 to 4, specifically as follows:

[0055] A 1# secondary water outlet valve 209 electrically connected to the control unit 300 is provided on the wall of the 1# secondary O tank 202 at the 1# secondary buffer dilution zone 211. When the 1# secondary water outlet valve 209 is opened, the effluent in the 1# secondary buffer dilution zone 211 of the 1# secondary O tank 202 can enter the secondary sedimentation tank through the 1# secondary water outlet valve 209. When the 1# secondary water outlet valve 209 is closed, the effluent in the 1# secondary buffer dilution zone 211 of the 1# secondary O tank 202 cannot enter the secondary sedimentation tank through the 1# secondary water outlet valve 209. The 1# secondary water outlet valve 209 is electrically connected to the control unit 300.

[0056] Example 6

[0057] like Figure 1 As shown, this embodiment is a further improvement on the basis of any one of the embodiments 1 to 5, specifically as follows:

[0058] A 2# secondary water outlet valve 210 electrically connected to the control unit 300 is provided on the wall of the 2# secondary O tank 204 at the 2# secondary buffer dilution zone 212. When the 2# secondary water outlet valve 210 is opened, the effluent in the 2# secondary buffer dilution zone 212 of the 2# secondary O tank 204 can enter the secondary sedimentation tank through the 2# secondary water outlet valve 210. When the 2# secondary water outlet valve 210 is closed, the effluent in the 2# secondary buffer dilution zone 212 of the 2# secondary O tank 204 cannot enter the secondary sedimentation tank through the 2# secondary water outlet valve 210. The 2# secondary water outlet valve 210 is electrically connected to the control unit 300.

[0059] Example 7

[0060] A multi-stage A / O pool sewage treatment method capable of dynamically switching between parallel and series modes, using a multi-stage A / O pool sewage treatment system capable of dynamically switching between parallel and series modes as in any one of Examples 1 to 5, comprises the following steps:

[0061] S10, wastewater flows into the 1# primary A pool 101 and the 2# primary A pool 103 of the primary A / O pool module, preferably with each group treating 50% of the load;

[0062] The 1# flow sensor 301 measures the flow rate in the 1# primary A tank 101, the 1# COD monitor 303 measures the COD value in the 1# primary A tank 101, and the 1# ammonia nitrogen monitor 305 measures the ammonia nitrogen value in the 1# primary A tank 101; and the 2# flow sensor 302 measures the flow rate in the 2# primary A tank 103, the 2# COD monitor 304 measures the COD value in the 2# primary A tank 103, and the 2# ammonia nitrogen monitor 306 measures the ammonia nitrogen value in the 2# primary A tank 103;

[0063] If the ammonia nitrogen concentration is ≤30 mg / L, the COD instantaneous load is ≤500 mg / L, and the flow fluctuation is <20%, the sludge in the secondary sedimentation tank will be returned to the 1# primary A tank 101 and the 2# primary A tank 103, and the sludge in the secondary sedimentation tank will be returned to the 1# secondary A tank 201 and the 2# secondary A tank 203, and the sludge return ratio will be fixed at 50% to 100%;

[0064] Denitrifying bacteria use organic matter in the influent as a carbon source to reduce nitrate in the return sludge to nitrogen (N2), achieving preliminary denitrification. Nitrifying bacteria oxidize ammonia nitrogen (NH3-N) to nitrate (NO3-), while degrading COD. The aeration rate is automatically adjusted based on feedback from the DO sensor to maintain dissolved oxygen (DO) in the O tank. The treated effluent from the 1# secondary O tank 202 and the 2# secondary O tank 204 is collected in a public secondary sedimentation tank. After mud and water separation, the supernatant enters the subsequent treatment unit.

[0065] If any of the following conditions is met: ammonia nitrogen concentration > 100 mg / L, COD instantaneous load > 1000 mg / L, flow fluctuation > 20%, or toxic substances are detected, the switching condition is triggered and the process enters S20;

[0066] S20, sending a switching instruction to the valve group and the lifting device to allow the primary A / O pool module and the secondary A / O pool module to operate in series;

[0067] Valve group adjustment: Close 1# primary outlet valve 109, 2# secondary outlet valve 210, 1# primary return valve 107, and 2# secondary return valve 208; open 2# primary return valve 108, 1# secondary return valve 207, 2# primary outlet valve 110, and 1# secondary outlet valve 209;

[0068] Lifting device adjustment:

[0069] Start the 1# first-level lifting device 105 to mix the effluent from the 1# first-level O tank 102 with the return sludge and then send it into the 2# first-level A tank 103 through the 1# return channel 113 and the 2# first-level return valve 108;

[0070] Start the 2# secondary lifting device 206 to mix the effluent from the 2# secondary O tank 204 with the return sludge and then send it into the 1# secondary A tank 201 through the 2# return channel 213 and the 1# secondary return valve 207;

[0071] Four-stage A / O series operation:

[0072] First-stage A / O: Initially degrades COD and ammonia nitrogen. The mixed liquid in the 1# primary O tank 102 is sent to the 2# primary A tank 103 via the 1# return channel 113 and the 2# primary return valve 108 using the 1# primary lifting device 105. Then, the effluent from the 2# primary O tank 104 enters the 2# secondary A tank 203 via the 2# primary outlet valve 110.

[0073] The third stage A / O: further nitrification and denitrification, the mixed liquid in the 2# secondary O tank 204 is sent to the 1# secondary A tank 201 through the 2# return channel 213 and the 1# secondary return valve 207 by the 2# secondary lifting device 206, so as to form a four-stage circulation. Then the four-stage circulation at this time is: A1 (1# primary A tank 101) → O1 (1# primary O tank 102) → A3 (2# primary A tank 103) → O3 (2# primary O tank 104) → A4 (2# secondary A tank 203) → O4 (2# secondary O tank 204) → A2 (1# secondary A tank 201) → O2 (1# secondary O tank 202). Of course, in actual application, if the corresponding valves are opened, it can also be: A3 → O3 → A1 → O1 → A2 → O2 → A4 → O4. Since the process is similar to the above, it is not repeated here.

[0074] Furthermore, the dissolved oxygen DO in the O tank in S10 is maintained at 2mg / L~3mg / L, the toxic substance in S20 is total hydrazine, and the total hydrazine concentration in S20 is >200mg / L. The toxic substances are monitored through the raw water of the plant.

[0075] Sludge return ratio: Increase to 150% to 200% to enhance microbial activity.

[0076] The innovation of this invention lies in the construction of an efficient and flexible multi-stage A / O pool system through the coordinated optimization of structure, process and control:

[0077] 1) Switchable modular structure design: Breaking the fixed layout of traditional A / O tanks, two groups of two-stage A / O tanks are designed as independent modules. Through the combination of a multi-channel valve group (such as a pneumatic butterfly valve) and a lifting device, dynamic switching between parallel mode and four-stage series mode is achieved. In parallel mode, the two groups of A / O tanks operate independently, reducing energy consumption and maintenance burden; in series mode, the lifting device drives the front-stage effluent and sludge mixture into the rear-stage tank body, forming a four-stage circulation, extending the hydraulic retention time, and fully enhancing nitrification and denitrification reactions, especially for the deep degradation of high-concentration ammonia nitrogen (such as above 100 mg / L) and toxic substances (such as total hydrazine 200 mg / L);

[0078] 2) Stepped buffering process driven by lifting and reflux: In series mode, a mixing and dilution zone is set up at the outlet of each A / O tank. The effluent from the front stage is mixed with the sludge return liquid and transported to the back stage tank through a lifting device. At the same time, the stepped structure gradually dilutes toxic substances (such as hydrazines) in the influent. Combined with the adaptive domestication of the microbial community, the toxicity inhibition concentration threshold is increased by 50%, significantly enhancing system stability.

[0079] 3) Intelligent dynamic control strategy: Based on real-time monitoring data from ammonia nitrogen, COD, and flow sensors, the system automatically triggers mode switching and parameter adjustments. For example, when influent ammonia nitrogen is detected to be greater than 100 mg / L or flow fluctuation is greater than 20%, the system switches to series mode and simultaneously increases the sludge return ratio to 150% to 200%. Simultaneously, shock-resistant nitrifying bacteria pre-stored in the culture chamber are added. When water quality stabilizes (e.g., ammonia nitrogen ≤ 30 mg / L), the system automatically resumes parallel mode to reduce energy consumption. This strategy addresses the hysteresis problem of traditional processes that rely on manual intervention, achieving a "perception-decision-execution" closed-loop control system, ensuring rapid response and sustained stable operation of the system under complex operating conditions.

[0080] 4) Significantly improved treatment efficiency: In series mode, the four-stage A / O tank extends the hydraulic retention time through gas stripping reflux, strengthening the synergistic effect of nitrification and denitrification reactions. The ammonia nitrogen removal rate is increased from less than 60% in the traditional parallel system to over 95%, and the COD removal rate is stabilized at over 90%;

[0081] 5) Significantly enhanced shock resistance: The series structure forms a "stepped buffer pool" that effectively alleviates the transient inhibition of toxic substances (such as hydrazines) on microorganisms through the dual effects of gradual dilution and biodegradation, expands the tolerance concentration fluctuation range by 50%, and avoids the risk of system collapse;

[0082] 6) Reduced energy consumption and operation and maintenance costs: In parallel mode, aeration volume is reduced by 30% to 40% (only two independent groups need to be maintained). In series mode, the low-power design of gas lift reflux uses gas lift power to replace high-energy-consuming mechanical pumps. The energy consumption of the gas lift device is reduced by more than 50% compared to mechanical pumps, and the overall energy consumption is reduced by 15% compared to traditional four-stage series systems. At the same time, the intelligent control strategy can dynamically adjust the operation mode according to water quality, reducing waste caused by excessive aeration or chemical addition.

[0083] 7) Rapid recovery and high adaptability: The system has a built-in bacterial culture chamber that can automatically add toxic-resistant nitrifying bacteria concentrate when it is impacted. Combined with the dynamic adjustment of the sludge return ratio (increased to 150% to 200% in series mode), the recovery period is shortened from the traditional 7 days to 3 days. In addition, the modular design supports flexible switching of operating modes. It is suitable for highly toxic wastewater (such as hydrazine hydrate and pharmaceutical wastewater) and can also cope with seasonal water surges (such as flow fluctuations of ±50% in the rainy season), achieving efficient adaptation of "one machine for multiple scenarios".

[0084] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A multi-stage A / O tank sewage treatment system that can dynamically switch between parallel and series modes, characterized by: include: 1# primary A pool (101), the 1# primary A pool (101) is connected to the 1# primary O pool (102), a 1# primary lifting device (105) for lifting the mixed liquid into the 1# return channel (113) is arranged in the 1# primary buffer dilution area (111) of the 1# primary O pool (102), the 1# primary return valve (107) and the 2# primary return valve (108) are respectively arranged in the 1# return channel (113) in the areas corresponding to the 1# primary A pool (101) and the 2# primary A pool (103), the 2# primary A pool (102) is connected to the 1# primary O pool (102), the 1# primary return valve (107) and the 2# primary return valve (108) are respectively arranged in the 1# primary A pool (101) and the 2# primary A pool (103), 3) is connected to the 2# primary O pool (104), the 2# primary O pool (104) is connected to the 2# secondary A pool (203) via the 2# primary outlet valve (110), the 2# secondary A pool (203) is connected to the 2# secondary O pool (204), a 2# secondary lifting device (206) for lifting the mixed liquid into the 2# return channel (213) is arranged in the 2# secondary buffer dilution area (212) of the 2# secondary O pool (204), and the 2# return channel (213) is located at the corresponding 1# secondary A pool (201) and the 2# secondary A pool (203). The area is provided with a 1# secondary reflux valve (207) and a 2# secondary reflux valve (208), the 1# primary O pool (102) is connected to the 1# secondary A pool (201) via the 1# primary outlet valve (109), the 1# secondary A pool (201) is connected to the 1# secondary O pool (202), the 2# primary buffer dilution area (112) of the 2# primary O pool (104) is provided with a 2# primary lifting device (106) for lifting the mixed liquid into the 1# reflux channel (113), the 1# secondary buffer dilution area (112) of the 1# secondary O pool (202 ... A 1# secondary lifting device (205) is arranged in the area (211) for lifting the mixed liquid into the 2# return channel (213); a 1# flow sensor (301), a 1# COD monitor (303) and a 1# ammonia nitrogen monitor (305) are respectively used to measure the flow rate, COD and ammonia nitrogen in the 1# primary A tank (101); a 2# flow sensor (302), a 2# COD monitor (304) and a 2# ammonia nitrogen monitor (306) are respectively used to measure the flow rate, COD and ammonia nitrogen in the 2# primary A tank (103).

2. The multi-stage A / O tank sewage treatment system capable of dynamically switching between parallel and series modes according to claim 1 is characterized in that: The 1# first-stage lifting device (105), the 2# first-stage lifting device (106), the 1# first-stage reflux valve (107), the 2# first-stage reflux valve (108), the 1# first-stage water outlet valve (109), the 2# first-stage water outlet valve (110), the 1# second-stage lifting device (205), the 2# second-stage lifting device (206), the 1# flow sensor (301), the 1# COD monitor (303), the 1# ammonia nitrogen monitor (305), the 2# flow sensor (302), the 2# COD monitor (304) and the 2# ammonia nitrogen monitor (306) are electrically connected to the control unit (300) respectively.

3. The multi-stage A / O tank sewage treatment system capable of dynamically switching between parallel and series modes according to claim 1 or 2, characterized in that: Also includes: A bacterial seed chamber (400) is used to release a toxic-resistant nitrifying bacteria concentrate into the 1# primary O tank (102) and the 2# primary O tank (104). The bacterial seed chamber (400) is electrically connected to the control unit (300). The dosage of the toxic-resistant nitrifying bacteria concentrate is 0.5 g / m 3 ~1.0g / m 3 .

4. The multi-stage A / O pool sewage treatment system capable of dynamically switching between parallel and series modes according to any one of claims 1 to 3, characterized in that: The 1# primary lifting device (105), the 1# secondary lifting device (205), the 2# primary lifting device (106) and the 2# secondary lifting device (206) all adopt gas stripping devices.

5. The multi-stage A / O pool sewage treatment system capable of dynamically switching between parallel and series modes according to any one of claims 1 to 4, characterized in that: The 1# secondary O2 pool (202) is provided with a 1# secondary water outlet valve (209) electrically connected to the control unit (300) on the pool wall at the 1# secondary buffer dilution zone (211).

6. The multi-stage A / O pool sewage treatment system capable of dynamically switching between parallel and series modes according to any one of claims 1 to 5, characterized in that: The 2# secondary O tank (204) is provided with a 2# secondary water outlet valve (210) electrically connected to the control unit (300) on the tank wall at the 2# secondary buffer dilution zone (212).

7. A multi-stage A / O pool sewage treatment method capable of dynamically switching between parallel and series modes, characterized in that: A multi-stage A / O tank sewage treatment system capable of dynamically switching between parallel and series modes according to any one of claims 1 to 6 comprises the following steps: S10, the wastewater flows into the 1# primary A pool (101) and the 2# primary A pool (103) of the primary A / O pool module; If the ammonia nitrogen concentration is ≤30 mg / L, the COD instantaneous load is ≤500 mg / L, and the flow fluctuation is <20%, the sludge in the secondary sedimentation tank is returned to the 1# primary A tank (101) and the 2# primary A tank (103), and the sludge in the secondary sedimentation tank is returned to the 1# secondary A tank (201) and the 2# secondary A tank (203), and the sludge return ratio is fixed at 50% to 100%; Denitrifying bacteria use organic matter in the influent as a carbon source to reduce nitrate in the return sludge to nitrogen gas, achieving preliminary denitrification. Nitrifying bacteria oxidize ammonia nitrogen to nitrate and degrade COD at the same time. The aeration volume is automatically adjusted according to the feedback from the DO sensor to maintain the dissolved oxygen in the O pool. The effluent treated by the 1# secondary O pool (202) and the 2# secondary O pool (204) is collected into the public secondary sedimentation tank. After the mud and water are separated, the supernatant enters the subsequent treatment unit. If any of the following conditions is met: ammonia nitrogen concentration > 100 mg / L, COD instantaneous load > 1000 mg / L, flow fluctuation > 20%, or toxic substances are detected, the switching condition is triggered and the process enters S20. S20, sending a switching instruction to the valve group and the lifting device to allow the primary A / O pool module and the secondary A / O pool module to operate in series; Valve group adjustment: close 1# first-stage outlet valve (109) and 2# second-stage outlet valve (210), open 2# first-stage return valve (108) and 1# second-stage return valve (207); Lifting device adjustment: Start the 1# first-stage lifting device (105), so that the effluent from the 1# first-stage O tank (102) is mixed with the return sludge and then sent into the 2# first-stage A tank (103) through the 1# return channel (113) and the 2# first-stage return valve (108); Start the 2# secondary lifting device (206), mix the effluent from the 2# secondary O tank (204) with the return sludge, and then send it into the 1# secondary A tank (201) through the 2# return channel (213) and the 1# secondary return valve (207); Four-stage A / O series operation: First stage A / O: preliminary degradation of COD and ammonia nitrogen, using the 1# first stage lifting device (105) to send the mixed liquid in the 1# first stage O tank (102) through the 1# return channel (113) and the 2# first stage return valve (108) into the 2# first stage A tank (103), and then the effluent of the 2# first stage O tank (104) enters the 2# second stage A tank (203) through the 2# first stage outlet valve (110); The third stage A / O: further nitrification and denitrification, using the 2# secondary lifting device (206) to send the mixed liquid in the 2# secondary O tank (204) through the 2# return channel (213) and the 1# secondary return valve (207) into the 1# secondary A tank (201), thus forming a four-stage cycle.

8. The multi-stage A / O pool sewage treatment method capable of dynamically switching between parallel and series modes according to claim 7, characterized in that: In S10, the dissolved oxygen (DO) in the O tank was maintained at 2 mg / L to 3 mg / L.

9. The multi-stage A / O pool sewage treatment method capable of dynamically switching between parallel and series modes according to claim 7, characterized in that: The toxic substance in S20 is total hydrazine.

10. The multi-stage A / O pool sewage treatment method capable of dynamically switching between parallel and series modes according to claim 9, characterized in that: The total hydrazine concentration in S20 was >200 mg / L.

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