A segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater: device and method

Abstract

This invention discloses a segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater. The segmented influent SBR process has n (≥3) series-connected A / O stages per treatment cycle. Based on the enterprise's water quality monitoring data and experience, an appropriate amount of high-COD concentration water is introduced to increase the influent C / N ratio, with concentrated influent at the beginning of each A stage. The first influent is low-C / N water, the second to n-1 influent are mixed water to increase the C / N ratio, and the nth influent is only a suitable amount of high-COD concentration water. Aerobic nitrification in each stage is controlled by pH and DO, and denitrification in each stage is controlled by pH and ORP. Based on the A / O stages... n The characteristics of pH and ORP changes over a period of time were used to determine A. n Whether the denitrification carbon source in the influent is sufficient during the specified period, combined with the A n The detection of COD concentration at the end of the time period is used to determine A. n Is there an excess of denitrification carbon source in the influent during a given period? For cases of insufficient or excessive carbon source, adjust A by fine-tuning... n The influent volume of water with high COD concentration during a given period is used to achieve deep denitrification.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a deep denitrification device and method for high-nitrogen organic wastewater using a segmented influent SBR process. SBR is the abbreviation for Sequencing Batch Reactor. Background Technology

[0002] In the past decade or so, the state has successively promulgated or revised industrial water pollutant discharge standards for various industries. Without exception, strict total nitrogen discharge standards have been stipulated for nitrogen-containing wastewater. For ecologically fragile areas, the requirements for total nitrogen discharge are even more stringent. [Examples: Water Pollutant Discharge Standard for Starch Industry (GB25461-2010), Ministry of Environmental Protection, September 2010; Water Pollutant Discharge Standard for Dairy Industry (Draft for Comments), Ministry of Environmental Protection; Water Pollutant Discharge Standard for Traditional Chinese Medicine Pharmaceutical Industry (GB21906-2008), Ministry of Environmental Protection, June 2008; Water Pollutant Discharge Standard for Fermented Alcohol and Baijiu Industry (GB27631-2011), Ministry of Environmental Protection, October 2011; etc.]

[0003] For high-nitrogen organic wastewater with good biodegradability, such as wastewater from grain deep processing, dairy products, brewing, and traditional Chinese medicine pharmaceutical manufacturing, although their water quality parameters vary, their treatment engineering technical specifications generally recommend using a biological treatment technology based on "anaerobic + aerobic" combined with physical and chemical treatment technologies to achieve the treatment goal. In this combined technology process system, organic matter and other resources in the wastewater are mainly recovered in the form of biogas in the "anaerobic stage," while nitrogen in the wastewater is mainly removed in the "aerobic stage" located at the end of the system. However, the effluent from the "anaerobic stage" is generally high-ammonia water with a low C / N ratio. Due to insufficient carbon source in the water, the total nitrogen removal effect of the subsequent "aerobic stage" is seriously affected. At the same time, since high-ammonia water consumes a large amount of alkali in the nitrification stage, and the alkalinity of the wastewater is limited, and the system does not receive alkali replenishment from denitrification, a large amount of alkali is often added to the aeration tank to avoid excessively low pH value caused by alkali consumption due to ammonia nitrogen oxidation. The problem of "high alkali consumption and excessive total nitrogen in effluent" is a common problem for all types of high ammonia organic wastewater treatment plants. Improving this situation is not only a prerequisite for ensuring the healthy development of enterprises, but also of great significance for protecting the ecological environment.

[0004] The staged influent SBR denitrification process can fully utilize the organic matter in the raw water to serve denitrification, and is especially suitable for deep denitrification treatment of wastewater with low C / N ratios. However, since the influent of the last stage of the staged influent SBR process usually only undergoes nitrification and does not have denitrification conditions, for the treatment of wastewater with high ammonia nitrogen, the effluent will inevitably contain a high concentration of nitrate nitrogen (the sum of nitrate nitrogen and nitrite nitrogen), which will affect the effluent water quality.

[0005] To fully leverage the advantages of the segmented influent SBR denitrification process and alleviate the aforementioned shortcomings, our team conducted research on deep denitrification of high-nitrogen organic wastewater, using corn starch wastewater as an example. In July 2021, we were granted a patent entitled "Denitrification Method for Corn Starch Wastewater Using Segmented Influent SBR Process with Short-cut Nitrification (ZL201910316234.X)". This method primarily treats the effluent from the anaerobic stage of the "anaerobic + aerobic" process at a company's wastewater treatment plant. An appropriate amount of high-organic-concentration influent is introduced before the anaerobic stage to increase the C / N ratio of the system's influent. A four-stage influent approach is used for the SBR process, and good deep denitrification results were achieved under laboratory conditions. However, our team discovered the following problems with the method described in the patent during on-site experiments at a company:

[0006] Due to the large fluctuations in the quality of wastewater from starch production enterprises, it is difficult to adjust and control the C / N ratio of the influent in the second and third stages of the four-stage SBR process and the influent volume with high organic matter concentration in the fourth stage in real time.

[0007] In the method described in the aforementioned patent [ZL201910316234.X], to meet the carbon source requirements of denitrification, the C / N ratio of the influent in the second and third stages of the four-stage SBR process and the total amount of organic matter in the high-organic-concentration influent in the fourth stage are required to be relatively constant. Under laboratory conditions, this patented method achieves excellent deep denitrification primarily because the test water (including the effluent from the anaerobic process stage and the influent from the anaerobic process stage with high organic matter concentration) is collected centrally from the enterprise's wastewater treatment plant within a short period, resulting in relatively stable water quality. Therefore, in the four-stage SBR process, the adjustment of the influent quality in the second and third stages and the control of the high-organic-concentration influent in the fourth stage can be performed according to a pre-set fixed procedure. However, during the on-site test at the enterprise's wastewater treatment plant, the test water used was the real-time effluent from the anaerobic process stage and the real-time influent from the anaerobic process stage. Due to various factors affecting the starch and its product production line (including periodic flushing tank discharge during starch production, material leakage on the production line, and the quality, moisture content, and origin of corn raw materials), the quality of the enterprise's production wastewater fluctuates greatly [see Table 1 attached to the application example of this invention. During the test, the chemical oxygen demand (COD) of the influent and effluent of the anaerobic process section of the enterprise's wastewater treatment station varied from 3400 to 8600 mg / L and 420 to 640 mg / L, respectively, and the total nitrogen varied from 380 to 600 mg / L and 340 to 580 mg / L, respectively]. To achieve the above-mentioned adjustment target, it is necessary to adjust the proportion of high organic matter concentration water in the second and third time periods and the influent volume of high organic matter concentration water in the fourth time period almost every day according to the actual changes in the quality of the production wastewater. This makes the operation and control cumbersome, the workload very large, and often the adjustment cannot be carried out normally.

[0008] Other high-nitrogen organic industrial wastewaters with similar water quality also exhibit significant fluctuations in water quality. Summary of the Invention

[0009] To address the aforementioned issues and fully leverage the denitrification advantages of the segmented influent SBR process, this invention, still using corn starch wastewater as an example, and based on the fluctuating characteristics of the production wastewater quality in enterprise wastewater treatment plants, combined with existing operational experience, provides a "segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater device and method." This aims to provide technical support for the technological upgrading and transformation of the aerobic process section of existing high-nitrogen organic wastewater treatment plants and for the process design of new plants.

[0010] Basic idea of ​​this invention

[0011] In the "anaerobic + aerobic" process of a corn starch enterprise wastewater treatment plant, the effluent with a low C / N ratio from the anaerobic process section is referred to as the first concentration water, and the influent with a high organic matter concentration from the anaerobic process section is referred to as the second concentration water.

[0012] (1) Taking the first concentration water as the main treatment target, the operation cycle of the traditional SBR process is divided into n (n≥3) anoxic / aerobic periods (A1 / O1~A1). n / O n Alternating hypoxic / aerobic operation;

[0013] (2) Statistical calculations were performed on the recent wastewater quality test data of the enterprise's wastewater treatment plant, and the proportion of second-concentration water with high organic matter concentration was determined in combination with experience in order to increase the C / N ratio, so that the mixed water after increasing the C / N ratio can meet the average carbon source requirements of denitrification.

[0014] (3) During the initial concentrated water intake of each A / O stage in the segmented feedwater SBR reactor, only water of the first concentration is introduced during the A1 stage, and water of the first concentration is introduced during the A2~A1 stages. n-1 The mixed water after the C / N ratio was increased during the period, in A n Only a certain amount of the second concentration water is introduced during a certain period. The amount of water introduced is determined based on statistical calculations of recent wastewater quality test data from the company's wastewater treatment plant and in combination with experience.

[0015] (4) The operation of each aerobic nitrification period is controlled online using pH and dissolved oxygen (DO) parameters, and the operation of each anoxic stirred denitrification period is controlled online using pH and oxidation-reduction potential (ORP) parameters;

[0016] (5) According to A n The characteristics of changes in online parameters pH and ORP over a period of time were used to determine A. n Whether the denitrification carbon source in the influent is sufficient during the specified period, combined with the A nThe detection of COD concentration at the end of the time period is used to determine A. n Is there an excess of denitrification carbon source in the influent during a given period? For cases of insufficient or excessive carbon source, adjust A by fine-tuning. n The inflow rate of the second concentration of water during the period is used to achieve the purpose of deep denitrification.

[0017] The segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater described in this invention can rationally allocate organic matter in the influent to serve denitrification, while simultaneously recovering alkalinity. Furthermore, it greatly simplifies the method described in patent [ZL201910316234.X] while achieving deep denitrification of corn starch wastewater.

[0018] Technical solution of the present invention

[0019] 1. The segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater described in this invention has the following characteristics.

[0020] The segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater comprises three parts: a water distribution system, a reaction system, and an operation control system.

[0021] The water distribution system includes: a first concentration water tank 1, a second concentration water tank 2, a mixing water tank 3, and an alkali solution tank 4;

[0022] The first concentration water tank 1 is equipped with a first concentration water tank inlet pipe 6, the second concentration water tank 2 is equipped with a second concentration water tank inlet pipe 7, and the mixing water tank 3 is equipped with a first pH sensor 32; the first concentration water tank 1 and the second concentration water tank 2 are respectively connected to the mixing water tank 3 through a first concentration water distribution pump 15 and a first concentration water distribution valve 16, a second concentration water distribution pump 17 and a second concentration water distribution valve 18, and a mixing water tank distribution pipe 8; the alkali tank 4 is connected to the mixing water tank 3 through an alkali dosing pump 19 and an alkali dosing valve 20.

[0023] The reaction system includes: an SBR reactor 5 and a blower 27;

[0024] The SBR reactor 5 is equipped with a stirrer 31, a second pH sensor 33, a DO sensor 34, an ORP sensor 35, and a liquid level sensor 36. The SBR reactor 5 is connected to a first concentration water inlet pipe 9, a mixed water inlet pipe 10, a second concentration water inlet pipe 11, an aeration pipe 12, a drain pipe 13, and a sludge discharge pipe 14. The first three pipes 9-11 are respectively equipped with a first concentration water inlet pump 21 and a first concentration water inlet valve 22, a mixed water inlet pump 23 and a mixed water inlet valve 24, and a second concentration water inlet pump 25 and a second concentration water inlet valve 26. The other ends of these three pipes 9-11 are respectively connected to the first concentration water tank 1, the mixed water tank 3, and the second concentration water tank 2. The aeration pipe 12, the drain pipe 13, and the sludge discharge pipe 14 are respectively equipped with an aeration valve 28, a drain valve 29, and a sludge discharge valve 30. The two ends of the aeration pipe 12 are respectively connected to a blower 27 and an aeration head 37.

[0025] The operation control system includes: a first online pH meter 38, a second online pH meter 39, an online DO meter 40, an online ORP meter 41, an online level meter 42, a data processor 43, and a process controller 47;

[0026] The data processor 43 includes pre-set parameters and calculation programs related to system operation control;

[0027] The first pH sensor 32 and the second pH sensor 33 are respectively connected to the first online pH meter 38 and the second online pH meter 39. The DO sensor 34, the ORP sensor 35, and the level sensor 36 are respectively connected to the online DO meter 40, the online ORP meter 41, and the online level meter 42. The signal output terminals of the five online meters 38 to 42 are connected to the signal input terminal 44 of the data processor 43. The data processor 43 is provided with a parameter setting and display terminal 45. The signal output terminal 46 of the data processor is connected to the process controller 47.

[0028] The process controller 47 is equipped with the following execution programs: first concentration water distribution pump 15 and first concentration water distribution valve 16, second concentration water distribution pump 17 and second concentration water distribution valve 18, alkali dosing pump 19 and alkali dosing valve 20, first concentration water inlet pump 21 and first concentration water inlet valve 22, mixed water inlet pump 23 and mixed water inlet valve 24, second concentration water inlet pump 25 and second concentration water inlet valve 26, blower 27 and aeration valve 28, agitator 31, drain valve 29 and sludge discharge valve 30.

[0029] The process controller signal output terminal 48 is connected to the first concentration water distribution pump 15 and the first concentration water distribution valve 16, the second concentration water distribution pump 17 and the second concentration water distribution valve 18, the alkali dosing pump 19 and the alkali dosing valve 20, the first concentration water inlet pump 21 and the first concentration water inlet valve 22, the mixed water inlet pump 23 and the mixed water inlet valve 24, the second concentration water inlet pump 25 and the second concentration water inlet valve 26, the blower 27 and the aeration valve 28, the agitator 31, the drain valve 29, and the sludge discharge valve 30 via control signal transmission lines.

[0030] 2. Technical procedures of the segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater as described in this invention

[0031] (1) Preparation of influent to the SBR reactor 5

[0032] 1) Draw water of the first concentration into the first concentration water tank 1, and draw water of the second concentration into the second concentration water tank 2;

[0033] 2) The first concentration water distribution pump 15 and the second concentration water distribution pump 17 draw water from the first concentration water tank 1 and the second concentration water tank 2 respectively, and mix the first concentration water and the second concentration water into the mixing water tank 3 in proportion through the first concentration water distribution valve 16, the second concentration water distribution valve 18 and the mixing water tank distribution pipe 8.

[0034] 3) The proportion λ1 of the second concentration water in the mixing tank 3 is determined by equation (1):

[0035] (1)

[0036] In the formula: C1 and C2 values ​​are the average COD concentrations of the first and second concentration waters calculated based on the measured data of COD concentrations of the first and second concentration waters of the wastewater treatment plant over the past 30 to 120 days, and the unit is mg / L;

[0037] C N The value is the average ammonia nitrogen concentration of the first concentration water, calculated based on the measured data of the first concentration water ammonia nitrogen concentration of the wastewater treatment plant over the past 30 to 120 days, and the unit is mg / L;

[0038] The K value varies depending on the operating mode. When the SBR reactor 5 operates in short-cut nitrification-denitrification denitrification (short-cut denitrification) mode, the K value is 3.7~4.0. When the SBR reactor 5 operates in full-process nitrification-denitrification denitrification (full-process denitrification) mode, the K value is 7.1~7.3.

[0039] For newly built wastewater treatment plants, if there is no measured data for 30 to 120 days, the average values ​​C1, C2, and C can be updated and calculated based on the measured data for the past 5 days, 15 days, 30 days, 60 days, and up to 120 days after the system has been running stably. N And the corresponding λ1 value is updated and calculated sequentially by equation (1);

[0040] 4) The ratio of the first concentration water to the mixing tank 3 is 1-λ1;

[0041] 5) The alkali solution is pumped from the alkali tank 4 into the mixing water tank 3 by the alkali pump 19. The pH value of the mixed water in the mixing water tank 3 is controlled by adjusting the alkali valve 20, while ensuring that the ratio of total alkalinity to total nitrogen concentration of the mixed water is greater than 4.0. The total alkalinity is expressed as CaCO3.

[0042] 6) When the total nitrogen concentration in the mixed water in the mixing tank 3 is greater than 220 mg / L for a long period (greater than 3 months), the SBR reactor 5 is operated in short-cut denitrification mode by controlling the operating conditions. At this time, during the start-up stage of the segmented influent SBR process system, the pH value of the mixed water in the mixing tank 3 is adjusted to 8.0~8.5. After the segmented influent SBR process system is stabilized during start-up, the pH value of the mixed water in the mixing tank 3 is adjusted to be no less than 7.5.

[0043] When the total nitrogen concentration in the mixed water in the mixing tank 3 cannot meet the requirement of being greater than 220 mg / L for a long period (more than 3 months), the SBR reactor 5 is adjusted to operate in full-process denitrification mode. At this time, the pH value of the mixed water in the mixing tank 3 is adjusted to be no less than 7.0.

[0044] 7) After the system is running normally and stably, C1, C2, and C3 should be calculated and updated every 10 to 120 days. N The value is determined, and the new λ1 value is calculated using equation (1);

[0045] (2) Start-up of the segmented water intake SBR process system

[0046] 1) Activated sludge with nitrification and denitrification functions is introduced into the SBR reactor 5 to make the average sludge concentration in the reactor 4500mg / L~5000mg / L;

[0047] 2) In one operating cycle of the SBR reactor 5, there are n A / O operating segments connected in series. During the initial A segment of each A / O segment, water is concentrated influent, and A1~A1 are... n The water intake times are referred to as the first to the nth water intake. The first water intake is the first concentration water in the first concentration water tank 1, the second to the (n-1)th water intake is the mixed water in the mixed water tank 3, and the nth water intake is only the second concentration water in the second concentration water tank 2.

[0048] 3) Control the SBR reactor 5 to have equal amounts of feed water for the first n-1 cycles, that is, the feed water volume Q1 of the first cycle with the first concentration of water and the feed water volumes Q2~Q of the second to n-1 cycles of mixed water. n-1 Equal; the inflow rate Q of the second concentration water in the nth iteration. n According to its proportion of the (n-1)th mixed water inflow Q n-1 The proportion λ2 is determined, i.e., Q n =λ2·Q n-1 ;

[0049] 4) Q n Q n-1 The value of the proportion λ2 is determined by equation (2):

[0050] (2)

[0051] In the formula C N The values ​​of C2 and K are the same as in equation (1);

[0052] 5) Following the above-mentioned water intake method, control the total nitrogen load of the SBR reactor 5 from small to large, and operate it periodically in an anoxic stirring / aerobic aeration alternation mode;

[0053] 6) When the total nitrogen concentration of the mixed water in the mixing tank 3 meets the operating conditions for short-cut denitrification, combined with the relatively high temperature of the mixed water [the temperature of the anaerobic reactor inlet (second concentration water) and the anaerobic reactor effluent (first concentration water) in the starch enterprise station is generally not lower than 30°C throughout the year] and the relatively high pH value (8.0~8.5) obtained by adjustment, the DO concentration of the SBR reactor 5 in the normal nitrification stage during each O period is controlled not to exceed 0.8 mg / L, and the short-cut nitrification is acclimatized and started; the so-called normal nitrification stage refers to the period when the DO concentration in the reactor mixture remains basically unchanged during the aeration nitrification process under fixed aeration conditions;

[0054] When the total nitrogen concentration of the mixed water in the mixing tank 3 does not meet the operating conditions for short-cut denitrification, the SBR reactor 5 is controlled to have sufficient dissolved oxygen (DO>2.0mg / L) in each O period to acclimate and start full-process nitrification.

[0055] After the segmented influent SBR process system is started up, it will enter the next stage of operation;

[0056] (3) During the stable operation phase of the system, the operation control mode of the SBR reactor 5

[0057] After the SBR process system is running stably, the average sludge concentration in the SBR reactor 5 is controlled to be 4500mg / L~5000mg / L, and the total effluent ratio is 0.6~0.8, according to the influent distribution method described in step (1) and the influent method described in step (2). The system is operated cyclically in an alternating anoxic stirring / aerobic aeration mode. The operation control steps for one cycle are as follows:

[0058] 1) First concentration water inlet stirring operation: During period A1, the first concentration water inlet pump 21 and the first concentration water inlet valve 22 are turned on in real time to draw water from the first concentration water tank 1 and introduce water into the SBR reactor 5 through the first concentration water inlet pipe 9. At the same time, the stirrer 31 is turned on to stir. When the set water inlet volume is reached, the first concentration water inlet valve 22 and the first concentration water inlet pump 21 are turned off in real time. Stirring continues for time t1 and then the stirrer 31 is turned off to stop stirring operation. t1 is 0~20min.

[0059] 2) Aeration operation: In O i During the (i≥1) period, the blower 27 and aeration valve 28 are turned on in real time to aerate the SBR reactor 5, remove organic matter from the water, and oxidize the ammonia nitrogen in the water into nitrate nitrogen.

[0060] During aeration operation, when operating in short-cut denitrification mode, the DO concentration in the normal nitrification section should be controlled to not exceed 1.5 mg / L; when operating in full-process denitrification mode, the DO concentration in the normal nitrification section should be controlled to not exceed 2.5 mg / L.

[0061] Online control strategy for the aeration process:

[0062] After aeration begins, the pH and DO signals in the SBR reactor 5 are monitored online in real time. The sampling interval t2 for online monitoring of pH and DO signals is 60 seconds. The collected pH and DO signal values ​​are subjected to a 4-value real-time sliding filter, i.e., the sliding average of the four values ​​is calculated, and the pH value between two adjacent sliding filter values ​​is also calculated. Lbi-1 pH Lbi With DO Lbi-1 DO Lbi The average rate of change K over time pHi =(pH Lbi -pH Lbi-1 ) / (t i -t i-1 ) and K DOi =(DO Lbi -DO Lbi-1 ) / (t i -t i-1 )value;

[0063] After aeration begins, when K is detected pH After the value is less than 0 for more than 3 minutes, continuous monitoring of K begins. pH and K DO The change in value, when K is monitored pH The value changes from negative to positive, while simultaneously satisfying K. DOi >K DOi-1 >K DOi-2 >K DOi-3 When the value is >0, the blower 27 and aeration valve 28 are shut off in real time to stop the aeration operation;

[0064] After the aeration operation is stopped, the system reads the preset number of water inflows n. If the read n value has not reached the n-1 number of water inflows, the system proceeds to step 3). If the n-1 number of water inflows is reached, the system jumps to step 4.

[0065] 3) Introduce mixed water and operate with stirring: In A i During the period (i≥2), the mixed water inlet pump 23 and the mixed water inlet valve 24 are turned on in real time to draw water from the mixed water tank 3 and feed water into the SBR reactor 5 through the mixed water inlet pipe 10. At the same time, the stirrer 31 is turned on to stir. When the set water intake is reached, the mixed water inlet valve 24 and the mixed water inlet pump 23 are turned off in real time to stop the water intake.

[0066] Control strategies for the stirring process:

[0067] After stirring begins, the pH and ORP signals in the SBR reactor 5 are monitored online in real time. The sampling interval t3 for online monitoring of pH and ORP signals is 30s~60s. The collected pH and ORP signal values ​​are subjected to 4-value real-time sliding filter processing, that is, the sliding average of the 4 values ​​is calculated, and the pH value between two adjacent sliding filter values ​​is also calculated. Lbi-1 pH Lbi With ORP Lbi-1 ORP Lbi The average rate of change K over time pHi =(pH Lbi -pH Lbi-1 ) / (t i -t i-1 ) and K ORPi =(ORP Lbi -ORP Lbi-1 ) / (t i -t i-1 )value;

[0068] During the stirring process, when K was monitored pH After the value is >0 for more than 1 minute, pay attention to monitoring K. pH and K ORPAs the value changes, K is started to be updated in real time. ORP Value and the set threshold K ORPk Comparison, K ORPk The value ranges from -1.2 mV / min to -1.4 mV / min;

[0069] When K is detected pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value of K is reached; or when a value greater than zero is detected. pH The value changes from large to small to K pH The absolute value is <0.003 min -1 And K ORP When the value's duration curve is still slowly decreasing without any characteristic signal appearing, the agitator 31 is turned off in real time to stop the agitation operation, and then the system returns to step 2) aeration operation;

[0070] 4) Introduce the second concentration of water and stir during operation: In A n During a certain period, the second concentration water inlet pump 25 and the second concentration water inlet valve 26 are turned on in real time to draw water from the second concentration water tank 2 and introduce it into the SBR reactor 5 for the nth time through the second concentration water inlet pipe 11. At the same time, the stirrer 31 is started to stir. When the set water intake is reached, the second concentration water inlet valve 26 and the second concentration water inlet pump 25 are turned off in real time to stop the water intake.

[0071] Similar to step 3) above, after stirring begins, the pH and ORP signals in the SBR reactor 5 are monitored online in real time. The sampling interval t3 for online monitoring of pH and ORP signals is 30s~60s. The collected pH and ORP signal values ​​are subjected to 4-value real-time sliding filter processing, and the pH value of two adjacent sliding filter values ​​is calculated simultaneously. Lbi-1 pH Lbi With ORP Lbi-1 ORP Lbi The average rate of change of the value over time, K pHi =(pH Lbi -pH Lbi-1 ) / (t i -t i-1 ) and K ORPi =(ORP Lbi -ORP Lbi-1 ) / (t i -t i-1 )value;

[0072] During the stirring process, when K was monitoredpH After a value is >0 for more than 1 minute, K should be monitored. pH and K ORP As the value changes, K is started to be updated in real time. ORP Value and the set threshold K ORPk Comparison, K ORPk The value ranges from -1.2 mV / min to -1.4 mV / min, and A is processed as follows. n The time-segmented mixing process is controlled online.

[0073] ① When K is detected pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value of the concentration is reached, the stirrer 31 is turned off immediately to stop stirring. If, at this time, the COD concentration in the mixture is detected to be greater than 115 mg / L, A is appropriately reduced during the next cycle. n Water inflow Q during the period n Q n The decrease in amount, while satisfying the period A n K appeared during the time-sharing operation pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk In addition to the absolute value, the COD concentration in the mixed solution must also be less than 115 mg / L;

[0074] ② When a K greater than zero is detected pH The value changes from large to small to K pH The absolute value is <0.003 min -1 And K ORP When the time-varying curve of the value is still slowly decreasing without any characteristic signal appearing, water can be drawn again from the second concentration water tank 2 through the second concentration water inlet pump 25 and the second concentration water inlet valve 26 during the stirring process, and the water is introduced at a rate of (0.03~0.15)Q. n The flow rate is continuously fed into the SBR reactor 5, while K is continuously monitored. pH and K ORP When the value changes, K is monitored pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ KORPk When the absolute value is reached, the second concentration water inlet valve 26 and the second concentration water inlet pump 25 are closed in real time to stop water intake, and the stirrer 31 is closed in real time to stop stirring operation.

[0075] 5) Short-time aeration operation: After stopping the stirring, the blower 27 and aeration valve 28 are turned on in real time to perform short-time aeration on the SBR reactor 5. The aeration time t4 is 8~25min. When the set aeration time t4 is reached, the blower 27 and aeration valve 28 are turned off in real time to stop the aeration operation.

[0076] 6) Sedimentation: After aeration is stopped, the mixture in the reactor is allowed to settle, thus achieving mud-water separation;

[0077] 7) Drainage and sludge removal: When the set sedimentation time t5 is reached, the drain valve 29 is opened in real time to discharge the treated supernatant from the SBR reactor 5 through the drain pipe 13. t5 is 30~70 min. According to the set sludge removal plan, the sludge removal valve 30 is opened in real time to discharge sludge through the sludge removal pipe 14. When the set drainage time t6 and sludge removal time t7 are reached, the drain valve 29 and sludge removal valve 30 are closed in real time to stop drainage and sludge removal. t6 is 15~40 min and t7 is 2~15 min.

[0078] 8) Idle: The SBR reactor 5 is in a standby state where it stops working. When the set idle time is reached, the system will automatically switch to the next cycle of operation.

[0079] The process of preparing the influent to the SBR reactor 5 and the operation of each step of the SBR reactor 5 are all controlled in real time by the process controller (47) according to the control strategy.

[0080] The relevant parameters in the feed water preparation process of the SBR reactor 5, such as the water quality parameters C1, C2, and C3 in equations (1) and (2) already stored in the data processor 43, are as follows: N Parameters such as the K value and the limit value of the pH of the mixed water in the mixing tank 3 are all set and modified through the parameter setting and display terminal 45; relevant parameters during the operation of the SBR reactor 5, such as the limit value of DO concentration in the normal nitrification section, the stirring time t1, the sampling times t2 and t3, and the K value, are also set and modified. ORP Critical value K of the parameter ORPk The parameters such as short-time aeration time t4, sedimentation time t5, drainage time t6, and sludge discharge time t7 can all be set and modified through the parameter setting and display terminal 45.

[0081] Technical Principles of the Invention

[0082] SeeFigure 1 The segmented feedwater SBR reactor of the present invention has n (n≥3) series A / O operating segments during one treatment cycle. Water is fed in concentratedly at the beginning of the A segment of each A / O, for a total of n times. The first time only water of the first concentration is fed in. The second to n-1 times are mixed water of the first concentration with a certain proportion of water of the second concentration, the proportion λ1 of the second concentration water being determined according to the aforementioned formula (1). The first n-1 times are equal amounts of water fed in, and the nth time only an appropriate amount of water of the second concentration is fed in, the amount of the second concentration water being Q. n =λ2·Q n-1 λ2 is determined by the aforementioned equation (2).

[0083] Based on the organic matter in the 2nd to (n-1st)th mixed water inlet and the organic matter in the nth second concentration water inlet determined by the above method, it can satisfy the requirements of A2~A n The average carbon source requirement for denitrification during the period.

[0084] The A1 period uses short-term stirring at fixed intervals. Its main function is to utilize the limited carbon source in the influent to remove nitrate nitrogen remaining in the reactor from the previous cycle through denitrification.

[0085] The function of the O1 period is to degrade the remaining organic matter in the reactor after the A1 period and to nitrify ammonia nitrogen through aerobic aeration. The aerobic nitrification process in the O1 period is controlled online using pH and DO parameters, ensuring sufficient ammonia nitrogen oxidation.

[0086] The function of the A2 stage is to utilize the organic matter in the second influent to carry out denitrification of the nitrate nitrogen produced in the O1 stage through stirring, while simultaneously recovering alkalinity. As mentioned earlier, the second influent is a mixed water with an increased C / N ratio. The organic matter in the influent can meet the average carbon source requirement for denitrification in the A2 stage, but it may not exactly meet the carbon source requirement for denitrification in the current cycle during the A2 stage.

[0087] The denitrification process during the A2 period was controlled online using pH and ORP parameters. This was based on the fact that when the carbon source for denitrification was sufficient during the A2 period, obvious characteristic points would appear on the pH and ORP duration curves monitored online to indicate the end of denitrification. Conversely, when the carbon source for denitrification was insufficient, the pH and ORP duration curves monitored online would also show different change characteristics compared to when the carbon source for denitrification was sufficient.

[0088] The next O2~O n-1 The function of the aeration period is the same as that of the O1 period, A3~A n-1 The function of this time period is the same as that of time period A2, because the nitrogen load of the second to (n-1)th influent flows is basically the same as that of the first flow, therefore O2~O n-1The operation and control method of the aeration process during the time period is the same as that of the O1 time period, A3~A n-1 The operation and control method of the time-period stirring process is the same as that of time period A2.

[0089] A n The function of the time period is to utilize the organic matter in the nth influent to remove O n-1 The nitrate nitrogen generated during the time period undergoes denitrification through stirring, while alkalinity is recovered. Since the organic matter in the mixed water and the second concentration water at the corresponding influent flow rate during time period A may not precisely meet the carbon source requirements for denitrification in the current cycle, therefore, in time period A... n During this period, three situations may occur in the influent of the second concentration water: suitable carbon source, excess carbon source, and insufficient carbon source. In these cases, it is possible to determine the appropriate course of action based on A. n The changes in pH and ORP parameters during the stirring process were analyzed, and different control methods were implemented for the system operation by combining the detection of COD concentration in the mixture.

[0090] ① When K is detected pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value of is reached, it indicates that the denitrification reaction process has ended, and A can be terminated immediately. n The stirring process during a certain period of time.

[0091] If the COD concentration in the mixture is detected to be less than 115 mg / L at this time, it indicates that A... n The carbon source in the second concentration water of the period is suitable; if the COD concentration in the mixed solution is detected to be greater than 115 mg / L, it indicates that A n If there is an excess of carbon source in the influent during the second concentration period, then A can be appropriately reduced during the next cycle. n Water inflow Q during the period n ;

[0092] ② When a K greater than zero is detected pH The value changes from large to small to K pHi The absolute value is <0.003 min -1 And K ORP When the time-limited curve of the value is still slowly decreasing without any characteristic signal appearing, it indicates that A n If the carbon source in the second concentration water in the influent is insufficient, then during stirring, the second concentration water can be continuously added to the SBR at a small flow rate until K2 is reached. pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value of the concentration is reached, the addition of the second concentration of water is stopped immediately, and the stirring process is terminated simultaneously.

[0093] Because the second concentration water is high COD concentration water, A n The inflow during that period was not large, therefore A n The ammonia nitrogen concentration in the mixed liquor is not high during the period, and will ultimately not affect the compliance of ammonia nitrogen and total nitrogen in the effluent.

[0094] O n The aeration process uses short-duration aeration at fixed intervals. Its main functions are: ① to remove nitrogen adhering to sludge particles, which is beneficial for sludge-water separation during sedimentation; ② to oxidize some of the ammonia nitrogen in the mixed liquor, so that the ammonia nitrogen in the effluent meets the standards; and ③ to oxidize the remaining organic matter in the mixed liquor, so that the COD in the effluent meets the standards.

[0095] Beneficial effects of the present invention

[0096] The segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater described in this invention has the following advantages:

[0097] (1) The denitrification effect is better than that of conventional segmented influent SBR process.

[0098] In conventional segmented influent SBR denitrification systems, without the addition of an external carbon source, when the influent C / N ratio is low or the influent C / N ratio is suitable but the ammonia nitrogen concentration is high, the system effluent will inevitably contain a high concentration of nitrate nitrogen, which will affect the effluent water quality.

[0099] The segmented feedwater SBR process apparatus and method of this invention simply and reasonably adjusts the organic matter in the second concentration water of the feedwater, so that the organic matter in the mixed water feedwater from the 2nd to the (n-1st)th times and the second concentration water feedwater from the nth time can meet the requirements of A2 to A. n The average carbon source requirement for denitrification during a given period can be controlled based on online parameters, allowing for the management of O1~O2. n-1 Time segment A2~A n Time period operation control, when A is detected n When the carbon source is insufficient or excessive during a certain period, A can be fine-tuned. n The issue of the influent volume for the second concentration of water in the time period was resolved. Experimental results show that when n=4, the segmented influent SBR process and method used to treat corn starch wastewater achieves stable denitrification, and the effluent quality is superior to the direct discharge standard in the industry standard (GB25461-2010).

[0100] (2) It can achieve good energy saving and consumption reduction effects.

[0101] 1) During each A period, the alkalinity generated by the denitrification process can be supplemented to the aerobic nitrification period, reducing pH fluctuations and alkali addition costs in the system.

[0102] 2) Organic matter in the influent during each A period can be fully utilized by denitrification, effectively reducing the energy consumption of oxidizing organic matter during the aerobic period, and also increasing the nitrification rate of autotrophic nitrifying bacteria.

[0103] 3) The sludge concentration in the segmented influent SBR reactor decreases with the increase of the number of influent cycles. The average sludge concentration in the reactor can be higher than that in a conventional single-influent SBR reactor, resulting in a stronger treatment capacity. Therefore, for the same effluent standard, the segmented influent SBR process can reduce the tank volume and save on infrastructure investment.

[0104] 4) It can reduce the treatment load of the anaerobic process section of the wastewater treatment plant and the energy consumption for lifting the influent of the anaerobic reactor.

[0105] The second-concentration water used to supplement the denitrification carbon source was not treated in the anaerobic process section and was directly introduced into the staged influent SBR reactor. The organic matter in this part of the water is mainly in A2~A n During the denitrification process, nitrogen is removed. On the other hand, the influent lift height of the anaerobic reactor is generally greater than 10m, while the aerobic process section, located at the end of the entire wastewater treatment system, can usually rely on gravity flow or a very small lift height to draw water. Therefore, the method of introducing a second concentration of water to provide a carbon source for denitrification in this invention reduces both the treatment load of the anaerobic process section and the energy consumption of lifting the influent to the anaerobic process section.

[0106] The experimental results show that, when using the segmented influent SBR process device and method described in this invention to treat corn starch wastewater, in a four-stage influent SBR process system, the proportion of the second concentration water used to supplement the denitrification carbon source is 24-30% (approximately 24% when operating in short-cut denitrification mode and approximately 30% when operating in full-process denitrification mode). Therefore, the treatment load of the anaerobic process section can be reduced by 24-30%, and the energy consumption for raising the influent of the corresponding anaerobic process section can also be reduced.

[0107] (3) The segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater described in this invention not only has a stable denitrification effect, but also greatly simplifies the operation and control process of the system compared with the aforementioned patent [ZL201910316234.X].

[0108] (4) The segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater described in this invention facilitates the upgrading and transformation of traditional SBR process systems. Attached Figure Description

[0109] Figure 1This refers to the operating mode of one treatment cycle of the segmented feedwater SBR reactor described in this invention.

[0110] Figure 2 This is a schematic diagram of the segmented feedwater SBR process system described in this invention;

[0111] Figure 3 A statistical graph showing the denitrification and organic matter degradation effects of a typical cycle in a segmented influent SBR process (influent n=4).

[0112] Figure 4 The curves show the time-bound changes of DO, pH, and ORP parameters with the concentrations of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen during a typical period.

[0113] Figure 2 In the diagram: 1—First concentration water tank, 2—Second concentration water tank, 3—Mixed water tank, 4—Alkali tank, 5—SBR reactor, 6—First concentration water tank inlet pipe, 7—Second concentration water tank inlet pipe, 8—Mixed water tank distribution pipe, 9—First concentration water inlet pipe, 10—Mixed water inlet pipe, 11—Second concentration water inlet pipe, 12—Aeration pipe, 13—Drainage pipe, 14—Sludge discharge pipe, 15—First concentration water distribution pump, 16—First concentration water distribution valve, 17—Second concentration water distribution pump, 18—Second concentration water distribution valve, 19—Alkali dosing pump, 20—Alkali dosing valve, 21—First concentration water inlet pump, 22—First concentration water inlet valve, 23—Mixed water inlet pump, 24—Mixed water inlet... 25—Second concentration water inlet pump, 26—Second concentration water inlet valve, 27—Blower, 28—Aeration valve, 29—Drain valve, 30—Sludge discharge valve, 31—Agitator, 32—First pH sensor, 33—Second pH sensor, 34—DO sensor, 35—ORP sensor, 36—Level sensor, 37—Aeration head, 38—First online pH meter, 39—Second online pH meter, 40—Online DO meter, 41—Online ORP meter, 42—Online level meter, 43—Data processor, 44—Signal input terminal, 45—Parameter setting and display terminal, 46—Data processor signal output terminal, 47—Process controller, 48—Process controller signal output terminal.

[0114] Figure 3 The horizontal axis represents the average duration of each time period from A1 to O4 during a typical cycle in the experiment, and the vertical axis represents the changes in the average concentrations of ammonia nitrogen, nitrite nitrogen, total nitrogen, and COD during each time period from A1 to O4 during a typical cycle in the experiment. This is because it represents almost 100% short-cut nitrification. Figure 3 The parameters do not contain nitrate nitrogen. Detailed Implementation

[0115] 1. Installation of the deep denitrification device for high-nitrogen organic wastewater in the segmented influent SBR process

[0116] The segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater comprises three components: a water distribution system, a reaction system, and an operation control system.

[0117] The specific implementation method is as follows:

[0118] (1) The setup of the water distribution system

[0119] The water distribution system includes: a first concentration water tank 1, a second concentration water tank 2, a mixing water tank 3, and an alkali solution tank 4.

[0120] The first concentration water tank 1 is equipped with a first concentration water tank inlet pipe 6, the second concentration water tank 2 is equipped with a second concentration water tank inlet pipe 7, and the mixing water tank 3 is equipped with a first pH sensor 32; the first concentration water tank 1 and the second concentration water tank 2 are respectively connected to the mixing water tank 3 through a first concentration water distribution pump 15 and a first concentration water distribution valve 16, a second concentration water distribution pump 17 and a second concentration water distribution valve 18, and a mixing water tank distribution pipe 8; the alkali tank 4 is connected to the mixing water tank 3 through an alkali dosing pump 19 and an alkali dosing valve 20.

[0121] (2) Setup of the reaction system

[0122] The reaction system includes: SBR reactor 5 and blower 27.

[0123] The SBR reactor 5 is equipped with a stirrer 31, a second pH sensor 33, a DO sensor 34, an ORP sensor 35, and a liquid level sensor 36. The SBR reactor 5 is connected to a first concentration water inlet pipe 9, a mixed water inlet pipe 10, a second concentration water inlet pipe 11, an aeration pipe 12, a drain pipe 13, and a sludge discharge pipe 14. The first three pipes 9-11 are respectively equipped with a first concentration water inlet pump 21 and a first concentration water inlet valve 22, a mixed water inlet pump 23 and a mixed water inlet valve 24, and a second concentration water inlet pump 25 and a second concentration water inlet valve 26. The other ends of these three pipes 9-11 are respectively connected to the first concentration water tank 1, the mixed water tank 3, and the second concentration water tank 2. The aeration pipe 12, the drain pipe 13, and the sludge discharge pipe 14 are respectively equipped with an aeration valve 28, a drain valve 29, and a sludge discharge valve 30. The two ends of the aeration pipe 12 are respectively connected to a blower 27 and an aeration head 37.

[0124] (3) The setup of the operation control system

[0125] The operation control system includes: a first online pH meter 38, a second online pH meter 39, an online DO meter 40, an online ORP meter 41, an online level meter 42, a data processor 43, and a process controller 47.

[0126] The data processor (43) includes pre-set parameters and calculation programs related to system operation control;

[0127] The first pH sensor 32 and the second pH sensor 33 are respectively connected to the first online pH meter 38 and the second online pH meter 39. The DO sensor 34, the ORP sensor 35, and the level sensor 36 are respectively connected to the online DO meter 49, the online ORP meter 41, and the online level meter 42. The signal output terminals of the five online meters 38 to 42 are connected to the signal input terminal 44 of the data processor 43. The data processor 43 is provided with a parameter setting and display terminal 45. The signal output terminal 46 of the data processor is connected to the process controller 47.

[0128] The process controller 47 contains the execution programs for the first concentration water distribution pump 15 and the first concentration water distribution valve 16, the second concentration water distribution pump 17 and the second concentration water distribution valve 18, the alkali dosing pump 19 and the alkali dosing valve 20, the first concentration water inlet pump 21 and the first concentration water inlet valve 22, the mixed water inlet pump 23 and the mixed water inlet valve 24, the second concentration water inlet pump 25 and the second concentration water inlet valve 26, the blower 27 and the aeration valve 28, the agitator 31, the drain valve 29 and the sludge discharge valve 30;

[0129] The process controller signal output terminal 48 is connected to the first concentration water distribution pump 15 and the first concentration water distribution valve 16, the second concentration water distribution pump 17 and the second concentration water distribution valve 18, the alkali dosing pump 19 and the alkali dosing valve 20, the first concentration water inlet pump 21 and the first concentration water inlet valve 22, the mixed water inlet pump 23 and the mixed water inlet valve 24, the second concentration water inlet pump 25 and the second concentration water inlet valve 26, the blower 27 and the aeration valve 28, the agitator 31, the drain valve 29, and the sludge discharge valve 30 via control signal transmission lines.

[0130] 2. Technical procedures of the segmented influent SBR process for deep denitrification of high-nitrogen organic wastewater

[0131] (1) Preparation of influent to the SBR reactor 5

[0132] 1) First concentration water is drawn into the first concentration water tank 1 through the first concentration water tank inlet pipe 6, and second concentration water is drawn into the second concentration water tank 2 through the second concentration water tank inlet pipe 7;

[0133] 2) Based on the measured COD concentration data of the first and second concentration wastewater from the wastewater treatment plant over the past 30 to 120 days, calculate the average COD concentrations C1 and C2 of the first and second concentration wastewater. Based on the measured ammonia nitrogen concentration data of the first concentration wastewater from the wastewater treatment plant over the past 30 to 120 days, calculate the average ammonia nitrogen concentration C of the first concentration wastewater. N ;

[0134] 3) The calculated water quality parameters C1, C2, and C3 are used to calculate the water quality parameters C1, C2, and C3. N The value is input to the data processor 43 through the parameter setting and display terminal 45, and the K value in the formula (1) is input at the same time; when the SBR reactor 5 is running in short-cut denitrification mode, the K value is 3.7~4.0, and when the SBR reactor 5 is running in full-process denitrification mode, the K value is 7.1~7.3; from the formula (1) already stored in the data processor (43), that is Calculate the proportion λ1 of the second concentration water in the mixing tank 3, and the proportion of the first concentration water added to the mixing tank is 1-λ1;

[0135] 4) After the value of λ1 is confirmed, the data processor signal output terminal 46 outputs a signal to drive the process controller 47, and outputs a control signal through the process controller signal output terminal 48 to start the first concentration water distribution pump 15 and the second concentration water distribution pump 17, which draw water from the first concentration water tank 1 and the second concentration water tank 2 respectively. By adjusting and controlling the first concentration water distribution valve 16 and the second concentration water distribution valve 18, the first concentration water and the second concentration water are proportionally distributed into the mixing water tank 3 through the mixing water tank distribution pipe 8.

[0136] 5) Start the alkali pump 19 to dispense alkali solution from the alkali tank 4 into the mixing water tank 3. Adjust the alkali valve 20 to control the pH value of the mixed water in the mixing water tank 3, while ensuring that the ratio of total alkalinity to total nitrogen in the mixed water is greater than 4.0, and the total alkalinity is expressed as CaCO3.

[0137] When the total nitrogen concentration in the mixed water in the mixing tank 3 is greater than 220 mg / L for a long period (greater than 3 months), the SBR reactor 5 can be adjusted to operate in short-cut denitrification mode. At this time, during the start-up stage of the segmented influent SBR process, the pH value of the mixed water in the mixing tank 3 is adjusted to 8.0~8.5. After the segmented influent SBR process system is started up and running stably, the pH value of the mixed water in the mixing tank 3 is adjusted to be no less than 7.5.

[0138] When the total nitrogen concentration in the mixed water in the mixing tank 3 cannot meet the requirement of being greater than 220 mg / L for a long period (more than 3 months), the SBR reactor 5 is adjusted to operate in full-process denitrification mode. At this time, the pH value of the mixed water in the mixing tank 3 is adjusted to be no less than 7.0.

[0139] 6) For newly built wastewater treatment plants, if there is no measured data for 30 to 120 days, the average values ​​C1, C2, and C can be updated and calculated based on the measured data for the past 5 days, 15 days, 30 days, 60 days, and up to 120 days after the system has been started and stabilized. N Each update calculates new C1, C2, and C. NAfter the data is collected, the influent to the SBR reactor 5 is adjusted according to steps 3) to 5) above.

[0140] 7) After the system is running normally and stably, C1, C2, and C3 should be calculated and updated every 10 to 120 days according to step 2) above. N value.

[0141] (2) Start-up of the segmented water intake SBR process system

[0142] 1) Activated sludge with nitrification and denitrification functions is fed into the segmented influent SBR reactor 5, so that the average sludge concentration in the reactor is 4500mg / L~5000mg / L;

[0143] 2) In one treatment cycle of the SBR reactor 5, there are n A / O running segments connected in series. Water is concentrated at the beginning of the A segment of each A / O segment, and there are a total of n water inlets. The first water inlet is the first concentration water in the first concentration water tank 1; the second to the (n-1)th water inlet is the mixed water in the mixed water tank 3; and the nth water inlet is only the second concentration water in the second concentration water tank 2.

[0144] 3) Control the influent volume of SBR reactor 5 to be equal for the first n-1 times, that is, the influent volume of the first concentration water Q1 and the influent volume of the mixed water from the second to the n-1th times Q2~Q n-1 Equal; the inflow rate Q of the second concentration water in the nth iteration. n According to its proportion of the (n-1)th mixed water inflow Q n-1 The proportion λ2 is determined, i.e., Q n =λ2·Q n-1 ;λ2 is derived from equation (2) already stored in the data processor (43), i.e. calculate;

[0145] 4) Following the above-described influent method, control the nitrogen load of the SBR reactor 5 influent from low to high gradually, and operate it cyclically in anoxic stirring / aerobic aeration alternation mode. During operation:

[0146] When the total nitrogen concentration of the mixed water in the mixing tank 3 meets the operating conditions for short-cut denitrification, combined with the higher temperature of the mixed water and the higher pH value (8.0~8.5) obtained by adjustment, the DO concentration of the SBR reactor 5 in each O period of the normal nitrification stage is controlled not to exceed 0.8 mg / L, and the short-cut nitrification is started by acclimatization. The so-called normal nitrification stage refers to the period when the DO concentration in the reactor mixture remains basically unchanged during the aeration nitrification process under the condition of fixed aeration rate.

[0147] When the total nitrogen concentration of the mixed water in the mixing tank 3 does not meet the operating conditions for short-cut denitrification, the SBR reactor 5 is controlled to have sufficient dissolved oxygen (DO>2.0mg / L) in each O period to acclimate and start full-process nitrification.

[0148] After the segmented influent SBR process system is started, it will enter the next stage of operation.

[0149] (3) During the stable operation phase of the system, the operation control mode of the segmented influent SBR reactor 5

[0150] After the SBR process system is running stably, the average sludge concentration in the SBR reactor 5 is controlled to be 4500mg / L~5000mg / L, and the total effluent ratio is taken as 0.6~0.8, according to the influent distribution method described in step (1) and the influent method described in step (2) above. The system is operated in a cyclical manner according to the alternating anoxic stirring / aerobic aeration method. The operation control steps of each cycle are as follows:

[0151] 1) Introduce water of the first concentration and stir.

[0152] During time period A1, the first concentration water inlet pump 21 and the first concentration water inlet valve 22 are turned on in real time to draw water from the first concentration water tank 1 and introduce it into the SBR reactor 5 through the first concentration water inlet pipe 9. At the same time, the stirrer 31 is turned on to start stirring. When the predetermined water intake is reached, the first concentration water inlet valve 22 and the first concentration water inlet pump 21 are turned off in real time. Stirring continues for time t1, and then the stirrer 31 is turned off to stop stirring. t1 is 0~20min.

[0153] 2) Aeration Operation

[0154] In O i During the (i≥1) period, the blower 27 and aeration valve 28 are turned on in real time to aerate the SBR reactor 5, remove organic matter from the water, and oxidize the ammonia nitrogen in the water into nitrate nitrogen.

[0155] During aeration operation, when operating in short-cut denitrification mode, the DO concentration in the normal nitrification section should be controlled to not exceed 1.5 mg / L; when operating in full-process denitrification mode, the DO concentration in the normal nitrification section should be controlled to not exceed 2.5 mg / L.

[0156] Online control strategy for the aeration process:

[0157] After aeration begins, the pH and DO signals in the SBR reactor 5 are monitored online in real time. The sampling interval t2 for online monitoring of pH and DO signals is 60 seconds. The collected pH and DO values ​​are subjected to a 4-value real-time sliding filter, i.e., the sliding average of the four values ​​is calculated, and the pH value between two adjacent sliding filter values ​​is also calculated. Lbi-1 pHLbi With DO Lbi-1 DO Lbi The average rate of change K over time pHi =(pH Lbi -pH Lbi-1 ) / (t i -t i-1 ) and K DOi =(DO Lbi -DO Lbi-1 ) / (t i -t i-1 )value;

[0158] After aeration begins, when K is detected pH After the value is less than 0 for more than 3 minutes, continuous monitoring of K begins. pH and K DO The change in value, when K is monitored pH The value changes from negative to positive, while simultaneously satisfying K. DOi >K DOi-1 >K DOi-2 >K DOi-3 When the value is >0, the blower 27 and aeration valve 28 are shut off in real time to stop the aeration operation;

[0159] After the aeration operation is stopped, the system reads the preset number of water inflows n. If the read n value has not reached the n-1 number of water inflows, the system proceeds to step 3). If the n-1 number of water inflows is reached, the system jumps to step 4.

[0160] 3) Introduce mixed water and run the agitator.

[0161] In A i During the period (i≥2), the mixed water inlet pump 23 and the mixed water inlet valve 24 are turned on in real time to draw water from the mixed water tank 3 and introduce it into the SBR reactor 5 through the mixed water inlet pipe 10. At the same time, the stirrer 31 is turned on to stir. When the predetermined water intake is reached, the mixed water inlet valve 24 and the mixed water inlet pump 23 are turned off in real time to stop the water intake.

[0162] The control strategy for the stirring process is as follows:

[0163] After stirring begins, the pH and ORP signals in the SBR reactor 5 are monitored online in real time. The sampling interval t3 for online monitoring of pH and ORP signals is 30s~60s. The collected pH and ORP values ​​are subjected to 4-value real-time sliding filter processing, that is, the sliding average of the 4 values ​​is calculated, and the pH of two adjacent sliding filter values ​​is also calculated. Lbi-1 pH Lbi With ORP Lbi-1 ORP Lbi The average rate of change K over timepHi =(pH Lbi -pH Lbi-1 ) / (t i -t i-1 ) and K ORPi =(ORP Lbi -ORP Lbi-1 ) / (t i -t i-1 )value;

[0164] During the stirring process, when K was monitored pH After the value is >0 for more than 1 minute, pay attention to monitoring K. pH and K ORP As the value changes, K is started to be updated in real time. ORP Value and the set threshold K ORPk Comparison, K ORPk The value ranges from -1.2 mV / min to -1.4 mV / min;

[0165] When K is detected pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value of K is reached; or when a value greater than zero is detected. pH The value changes from large to small to K pH The absolute value is <0.003 min -1 And K ORP When the value's duration curve is still slowly decreasing without any characteristic signal appearing, the agitator 31 is turned off in real time to stop the agitation operation, and then the system returns to step 2) aeration operation;

[0166] 4) Introduce the second concentration of water and stir.

[0167] In A n During a certain period, the second concentration water inlet pump 25 and the second concentration water inlet valve 26 are turned on in real time to draw water from the second concentration water tank 2 and introduce it into the SBR reactor 5 for the nth time through the second concentration water inlet pipe 11. At the same time, the stirrer 31 is started to stir. When the set water intake is reached, the second concentration water inlet valve 26 and the second concentration water inlet pump 25 are turned off in real time to stop the water intake.

[0168] Similar to step 3) above, after stirring begins, the pH and ORP signals in the SBR reactor 5 are monitored online in real time. The sampling interval t3 for online monitoring of pH and ORP signals is 30s~60s. At the same time, the collected pH and ORP values ​​are subjected to 4-value real-time sliding filter processing, and the pH value between two adjacent sliding filter values ​​is calculated.Lbi-1 pH Lbi With ORP Lbi-1 ORP Lbi The average rate of change of the value over time, K pHi =(pH Lbi -pH Lbi-1 ) / (t i -t i-1 ) and K ORPi =(ORP Lbi -ORP Lbi-1 ) / (t i -t i-1 )value;

[0169] During the stirring process, when K was monitored pH After a value is >0 for more than 1 minute, K should be monitored. pH and K ORP As the value changes, K is started to be updated in real time. ORP Value and the set threshold K ORPk Comparison, K ORPk The value ranges from -1.2 mV / min to -1.4 mV / min, and A is processed as follows. n The time-segmented mixing process is controlled online.

[0170] ① When K is detected pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value of COD is reached, the stirrer 31 is turned off immediately to stop stirring. If, at this time, the COD concentration in the mixture is detected to be greater than 115 mg / L, A is appropriately reduced during the next cycle. n Water inflow Q during the period n Q n The decrease in amount, while satisfying the period A n K appeared during the time-sharing operation pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk In addition to the absolute value, the COD concentration in the mixed solution must also be less than 115 mg / L;

[0171] ② When a K greater than zero is detected pH The value changes from large to small to K pH The absolute value is <0.003 min -1 And KORP When the time-varying curve of the value is still slowly decreasing without any characteristic signal appearing, water can be drawn again from the second concentration water tank 2 through the second concentration water inlet pump 25 and the second concentration water inlet valve 26 during the stirring process, and the water is introduced at a rate of (0.03~0.15)Q. n The flow rate is continuously fed into the SBR reactor 5, while K is continuously monitored. pH and K ORP When the value changes, K is monitored pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value is reached, the second concentration water inlet valve 26 and the second concentration water inlet pump 25 are closed in real time to stop water intake, and the stirrer 31 is closed in real time to stop stirring operation.

[0172] 5) Short-duration aeration operation

[0173] After stirring is stopped, the blower 27 and aeration valve 28 are turned on in real time to aerate the SBR reactor 5 for a short time, with the aeration time t4 being 8~25min; when the set aeration time t4 is reached, the blower 27 and aeration valve 28 are turned off in real time to stop the aeration operation.

[0174] 6) Precipitation

[0175] After stopping the aeration operation, the mixture in the SBR reactor 5 is allowed to settle, thus achieving mud-water separation.

[0176] 7) Drainage and sludge removal

[0177] When the set sedimentation time t5 is reached, the drain valve 29 is opened in real time to discharge the treated supernatant from the SBR reactor 5 through the drain pipe 13. t5 is 30~70 min. According to the set sludge discharge plan, the sludge discharge valve 30 is opened in real time to discharge sludge through the sludge discharge pipe 14. When the set drainage time t6 and sludge discharge time t7 are reached, the drain valve 29 and sludge discharge valve 30 are closed in real time to stop drainage and sludge discharge. t6 is 15~70 min and t7 is 2~20 min.

[0178] 8) Idle

[0179] SBR reactor 5 is in a standby state where it has stopped working. After the predetermined idle time is reached, the system will automatically start the next cycle.

[0180] Application Examples

[0181] The first and second concentration water used in the experiment were the effluent and influent of the anaerobic process section of the wastewater treatment plant of a large corn starch enterprise, respectively. The water quality parameters of the enterprise's wastewater treatment plant during the experiment are shown in Table 1.

[0182] Table 1. Water quality parameters of corn starch wastewater used in the experiment.

[0183]

[0184] The effective volume of the SBR reactor used in the experiment was 12L, and the total fill / drainage ratio was 0.67. The water distribution method described in this invention was adopted. According to the water quality conditions in Table 1, the K values ​​in equations (1) and (2) of the preceding technical process were taken as 3.7~4.0. The SBR reactor operated cyclically in a four-stage alternating anoxic / aerobic influent mode, controlling the average sludge concentration of the SBR reactor to be approximately 5000 mg / L. The experiment was conducted at room temperature, with a mixed liquor temperature of 24~27℃. Following the operation control method described in this invention, the anoxic stirring process during periods A2~A4 was controlled online using pH and ORP parameters, and the aeration nitrification process during periods O1~O3 was controlled online using pH and DO parameters. The stirring operation lasted approximately 5~8 minutes after influent in period A1, and the aeration time during period O4 was approximately 8 minutes. Under these operating conditions, the SBR reactor achieved long-term stable operation with a nitrite nitrogen accumulation rate exceeding 98% during the aerobic period.

[0185] Figure 3 To statistically evaluate the denitrification and organic matter degradation performance of a typical cycle in a segmented influent SBR process during the experiment, the following data was collected: Figure 3 As can be seen, for the test water shown in Table 1, the average concentrations of COD, ammonia nitrogen, and total nitrogen in the system effluent were 85.0 mg / L, 14 mg / L, and 25 mg / L, respectively, all of which are better than the industry standard (GB25461-2010) direct discharge standard.

[0186] Figure 4 The graphs show the time-varying values ​​of DO, pH, and ORP as a function of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen concentrations during a typical cycle, assuming sufficient carbon source for denitrification (experimental data for periods A1 and O4 are not shown in the figure). Figure 4 It can be seen that at the end of nitrification in each aeration period, a distinct characteristic point A appears in the DO and pH duration curves to indicate this, and at the end of denitrification in each anoxic period, a distinct characteristic point B appears in the pH and ORP duration curves to indicate this.

[0187] The above application examples, using corn starch wastewater as an example, further illustrate the denitrification effect of the present invention in conjunction with specific embodiments, facilitating a better understanding and application of the invention by those skilled in the art. The specific embodiments of the present invention are also applicable to the treatment of high-nitrogen organic wastewater from other grain deep processing, dairy products, brewing, and traditional Chinese medicine pharmaceutical manufacturing. It should not be considered that the specific embodiments of the present invention are limited to these descriptions; any simple modifications made to the present invention by those skilled in the art are within the scope of protection of the present invention.

[0188] This invention can provide technical support for the technological upgrading and transformation of the aerobic process section of existing starch wastewater treatment plants with "anaerobic + aerobic" biological treatment technology and similar high-nitrogen organic wastewater treatment plants, as well as for the process design of new plants.

Claims

1. A method for deep denitrification of high-nitrogen organic wastewater in a segmented influent SBR process, characterized in that: The deep denitrification method is performed using the following apparatus: The device comprises three parts: a water distribution system, a reaction system, and an operation control system. The water distribution system includes: a first concentration water tank (1), a second concentration water tank (2), a mixing water tank (3), and an alkali solution tank (4); The first concentration water tank (1) is provided with a first concentration water tank inlet pipe (6), the second concentration water tank (2) is provided with a second concentration water tank inlet pipe (7), and the mixing water tank (3) is provided with a first pH sensor (32); the first concentration water tank (1) and the second concentration water tank (2) are respectively connected to the mixing water tank (3) through a first concentration water distribution pump (15) and a first concentration water distribution valve (16), a second concentration water distribution pump (17) and a second concentration water distribution valve (18), and a mixing water tank distribution pipe (8); the alkali tank (4) is connected to the mixing water tank (3) through an alkali injection pump (19) and an alkali injection valve (20); The reaction system includes: an SBR reactor (5) and a blower (27); The SBR reactor (5) is equipped with a stirrer (31), a second pH sensor (33), a DO sensor (34), an ORP sensor (35), and a liquid level sensor (36); the SBR reactor (5) is connected to a first concentration water inlet pipe (9), a mixed water inlet pipe (10), a second concentration water inlet pipe (11), an aeration pipe (12), a drain pipe (13), and a sludge discharge pipe (14); a first concentration water inlet pump (21) and a first concentration water inlet valve (22) are respectively installed on the first concentration water inlet pipe (9), the mixed water inlet pipe (10), and the second concentration water inlet pipe (11), as well as a mixed water inlet pump. (23) and mixed water inlet valve (24), second concentration water inlet pump (25) and second concentration water inlet valve (26), the other end of the first concentration water inlet pipe (9), the mixed water inlet pipe (10) and the second concentration water inlet pipe (11) are respectively connected to the first concentration water tank (1), the mixed water tank (3) and the second concentration water tank (2); the aeration pipe (12), the drain pipe (13) and the sludge discharge pipe (14) are respectively provided with an aeration valve (28), a drain valve (29) and a sludge discharge valve (30), the two ends of the aeration pipe (12) are respectively connected to the blower (27) and the aeration head (37); The operation control system includes: a first online pH meter (38), a second online pH meter (39), an online DO meter (40), an online ORP meter (41), an online level meter (42), a data processor (43), and a process controller (47); The data processor (43) includes pre-set parameters and calculation programs related to system operation control; The first pH sensor (32) and the second pH sensor (33) are respectively connected to the first online pH meter (38) and the second online pH meter (39). The DO sensor (34), the ORP sensor (35), and the liquid level sensor (36) are respectively connected to the online DO meter (40), the online ORP meter (41), and the online liquid level meter (42). The signal output terminals of the first online pH meter (38), the second online pH meter (39), the online DO meter (40), the online ORP meter (41), and the online liquid level meter (42) are connected to the signal input terminal (44) of the data processor (43). The data processor (43) is provided with a parameter setting and display terminal (45). The signal output terminal (46) of the data processor is connected to the process controller (47). The process controller (47) is equipped with the execution programs of the first concentration water distribution pump (15) and the first concentration water distribution valve (16), the second concentration water distribution pump (17) and the second concentration water distribution valve (18), the alkali dosing pump (19) and the alkali dosing valve (20), the first concentration water inlet pump (21) and the first concentration water inlet valve (22), the mixed water inlet pump (23) and the mixed water inlet valve (24), the second concentration water inlet pump (25) and the second concentration water inlet valve (26), the blower (27) and the aeration valve (28), the agitator (31), the drain valve (29) and the sludge discharge valve (30); The process controller signal output terminal (48) is connected to the first concentration water distribution pump (15) and the first concentration water distribution valve (16), the second concentration water distribution pump (17) and the second concentration water distribution valve (18), the alkali dosing pump (19) and the alkali dosing valve (20), the first concentration water inlet pump (21) and the first concentration water inlet valve (22), the mixed water inlet pump (23) and the mixed water inlet valve (24), the second concentration water inlet pump (25) and the second concentration water inlet valve (26), the blower (27) and the aeration valve (28), the agitator (31), the drain valve (29), and the sludge discharge valve (30) respectively via the control signal transmission line; The deep denitrification method is characterized by comprising the following steps: (1) Preparation of the influent to the SBR reactor (5): 1) Draw water of the first concentration into the first concentration water tank (1), and draw water of the second concentration into the second concentration water tank (2); 2) The first concentration water distribution pump (15) and the second concentration water distribution pump (17) draw water from the first concentration water tank (1) and the second concentration water tank (2) respectively, and mix the first concentration water and the second concentration water into the mixing water tank (3) in proportion through the first concentration water distribution valve (16), the second concentration water distribution valve (18) and the mixing water tank distribution pipe (8); 3) The proportion λ1 of the second concentration water in the mixing tank (3) is determined by equation (1): (1) In the formula: C1 and C2 values ​​are the average COD concentrations of the first and second concentration waters calculated based on the measured data of COD concentrations of the first and second concentration waters of the wastewater treatment plant over the past 30 to 120 days, and the unit is mg / L; C N The value is the average ammonia nitrogen concentration calculated based on the measured data of the first concentration water ammonia nitrogen concentration of the wastewater treatment plant over the past 30 to 120 days, and the unit is mg / L; The K value is divided into two cases: when the SBR reactor (5) is running in short-cut denitrification mode, the K value is 3.7~4.0; when the SBR reactor (5) is running in full-process denitrification mode, the K value is 7.1~7.

3. For newly built wastewater treatment plants, since there is no measured data for 30 to 120 days, the average values ​​C1, C2, and C are updated based on the measured data for the past 5 days, 15 days, 30 days, 60 days, and up to 120 days after the system has been running stably. N And the corresponding λ1 value is updated and calculated sequentially by equation (1); 4) The ratio of the first concentration water to the mixing tank (3) is 1-λ1; 5) The alkali solution is dispensed from the alkali tank (4) into the mixing water tank (3) by the alkali pump (19). The pH value of the mixed water in the mixing water tank (3) is controlled by adjusting the alkali valve (20). At the same time, the ratio of the total alkalinity to the total nitrogen concentration of the mixed water is greater than 4.

0. The total alkalinity is expressed as CaCO3. 6) When the total nitrogen concentration in the mixed water in the mixing tank (3) is greater than 220 mg / L for more than 3 months, the SBR reactor (5) is operated in short-range denitrification mode by controlling the operating conditions. At this time, during the start-up stage of the segmented water intake SBR process system, the pH value of the mixed water in the mixing tank (3) is adjusted to 8.0~8.

5. After the segmented water intake SBR process system is started up and running stably, the pH value of the mixed water in the mixing tank (3) is adjusted to be no less than 7.

5. When the total nitrogen concentration in the mixed water in the mixing tank (3) cannot meet the requirement of being greater than 220 mg / L for more than 3 months, the SBR reactor (5) is adjusted to operate in full-process denitrification mode. At this time, the pH value of the mixed water in the mixing tank (3) is adjusted to be not less than 7.

0. 7) After the system is running normally and stably, C1, C2, and C3 should be calculated and updated every 10 to 120 days. N The value is determined, and the new λ1 value is calculated using equation (1); (2) Start-up of the segmented feedwater SBR process system: 1) Activated sludge with nitrification and denitrification functions is fed into the SBR reactor (5) so that the average sludge concentration in the SBR reactor (5) is 4500mg / L~5000mg / L; 2) In one operating cycle of the SBR reactor (5), there are n A / O operating segments connected in series. At the beginning of the A segment of each A / O, water is concentrated and A1~A1 is added. n The water intake times are referred to as the first to the nth water intake times. The first water intake is the first concentration water in the first concentration water tank (1), the second to the n-1th water intake is the mixed water in the mixed water tank (3), and the nth water intake is only the second concentration water in the second concentration water tank (2). 3) Control the SBR reactor (5) to have equal amounts of feed water for the first n-1 times, that is, the feed water volume Q1 of the first time with the first concentration of water and the feed water volume Q2~Q of the second to n-1 times of the mixed water. n-1 Equal; the inflow rate Q of the second concentration water in the nth iteration. n According to its proportion of the (n-1)th mixed water inflow Q n-1 The proportion λ2 is determined, i.e., Q n =λ2·Q n-1 ; 4) Q n Q n-1 The value of the proportion λ2 is determined by equation (2): (2) In the formula: C N The values ​​of C2 and K are the same as in equation (1); 5) According to the above water intake method, control the total nitrogen load of the SBR reactor (5) from small to large, and operate it in a periodic manner according to the alternating mode of anoxic stirring / aerobic aeration; 6) When the total nitrogen concentration of the mixed water in the mixing tank (3) meets the operating conditions for short-cut denitrification, combined with the high temperature of the mixed water and the pH value of 8.0~8.5 obtained by adjustment, the DO concentration of the SBR reactor (5) in the normal nitrification stage during each O period is controlled not to exceed 0.8 mg / L, and the short-cut nitrification is started by acclimatization; the so-called normal nitrification stage refers to the period during which the DO concentration in the mixed liquor of the SBR reactor (5) remains basically unchanged during the aeration nitrification process under fixed aeration conditions; When the total nitrogen concentration of the mixed water in the mixing tank (3) does not meet the operating conditions for short-cut denitrification, the SBR reactor (5) is controlled to have sufficient dissolved oxygen and DO concentration >2.0 mg / L in each O period to start full-process nitrification. After the segmented influent SBR process system is started up, it will enter the next stage of operation; (3) During the stable operation phase of the system, the operation control mode of the SBR reactor (5) is as follows: After the SBR process system is running stably, the average sludge concentration in the SBR reactor (5) is controlled to be 4500mg / L~5000mg / L, and the total effluent ratio is taken as 0.6~0.8, according to the influent distribution method described in step (1) and the influent method described in step (2) above. The system is operated in a cyclical manner according to the alternating anoxic stirring / aerobic aeration method. The operation control steps of one cycle are as follows: 1) First concentration water stirring operation: During the A1 period, the first concentration water inlet pump (21) and the first concentration water inlet valve (22) are turned on in real time. Water is drawn from the first concentration water tank (1) and fed into the SBR reactor (5) through the first concentration water inlet pipe (9). At the same time, the stirrer (31) is turned on to stir. When the set water inlet volume is reached, the first concentration water inlet valve (22) and the first concentration water inlet pump (21) are turned off in real time. Stirring continues for t1 time and then the stirrer (31) is turned off to stop stirring. t1 is 0~20min. 2) Aeration operation: In O i During the period i≥1, the blower (27) and the aeration valve (28) are turned on in real time to aerate the SBR reactor (5), remove organic matter from the water, and oxidize the ammonia nitrogen in the water into nitrate nitrogen; During aeration operation, when operating in short-cut denitrification mode, the DO concentration in the normal nitrification section should be controlled to not exceed 1.5 mg / L; when operating in full-process denitrification mode, the DO concentration in the normal nitrification section should be controlled to not exceed 2.5 mg / L. Online control strategy for the aeration process: After aeration begins, the pH and DO signals in the SBR reactor (5) are monitored online in real time. The sampling interval t2 for online monitoring of the pH and DO signals is 60s. The collected pH and DO signal values ​​are subjected to 4-value real-time sliding filtering, that is, the sliding average of the 4 values ​​is calculated, and the pH value between two adjacent sliding filtering values ​​is also calculated. Lbi-1 pH Lbi With DO Lbi-1 DO Lbi The average rate of change K over time pHi =(pH Lbi -pH Lbi-1 ) / (t i -t i-1 ) and K DOi =(DO Lbi -DO Lbi-1 ) / (t i -t i-1 )value; After aeration begins, when K is detected... pH After the value is less than 0 for more than 3 minutes, continuous monitoring of K begins. pH and K DO The change in value, when K is monitored pH The value changes from negative to positive, while simultaneously satisfying K. DOi >K DOi-1 >K DOi-2 >K DOi-3 When the value is >0, the blower (27) and the aeration valve (28) are shut down in real time to stop the aeration operation; After the aeration operation is stopped, the system reads the preset number of water inflows n. If the read n value has not reached the n-1 number of water inflows, the system proceeds to step 3). If the n-1 number of water inflows is reached, the system jumps to step 4. 3) Introduce mixed water and operate with stirring: In A i During the time period i≥2, the mixed water inlet pump (23) and the mixed water inlet valve (24) are turned on in real time to draw water from the mixed water tank (3) and feed water into the SBR reactor (5) through the mixed water inlet pipe (10). At the same time, the stirrer (31) is turned on to stir and run. When the set water intake is reached, the mixed water inlet valve (24) and the mixed water inlet pump (23) are turned off in real time to stop the water intake. Control strategies for the stirring process: After stirring begins, the pH and ORP signals in the SBR reactor (5) are monitored online in real time. The sampling interval t3 for monitoring the pH and ORP signals is 30s to 60s. The collected pH and ORP signal values ​​are subjected to 4-value real-time sliding filtering, that is, the sliding average of the 4 values ​​is calculated, and the pH value of two adjacent sliding filtering values ​​is calculated. Lbi-1 pH Lbi With ORP Lbi-1 ORP Lbi The average rate of change K over time pHi =(pH Lbi -pH Lbi-1 ) / (t i -t i-1 ) and K ORPi =(ORP Lbi -ORP Lbi-1 ) / (t i -t i-1 )value; During the stirring process, when K was monitored pH After the value is >0 for more than 1 minute, pay attention to monitoring K. pH and K ORP As the value changes, K is started to be updated in real time. ORP Value and the set threshold K ORPk Comparison, K ORPk The value ranges from -1.2 mV / min to -1.4 mV / min; When K is detected pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi The absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value of K is reached; or when a value greater than zero is detected. pH The value changes from large to small to K pH The absolute value is <0.003 min -1 And K ORP When the time curve of the value is still slowly decreasing and no characteristic signal appears, the agitator (31) is turned off in real time, the agitation operation is stopped, and then the system returns to the aeration operation in step 2). 4) Introduce the second concentration of water and stir during operation: In A n During a certain period, the second concentration water inlet pump (25) and the second concentration water inlet valve (26) are turned on in real time to draw water from the second concentration water tank (2) and introduce it into the SBR reactor (5) for the nth time through the second concentration water inlet pipe (11). At the same time, the stirrer (31) is started to stir. When the set water intake is reached, the second concentration water inlet valve (26) and the second concentration water inlet pump (25) are turned off in real time to stop the water intake. Similar to step 3) above, after stirring begins, the pH and ORP signals in the SBR reactor (5) are monitored online in real time. The sampling interval t3 for monitoring the pH and ORP signals is 30s~60s. The collected pH and ORP signal values ​​are subjected to 4-value real-time sliding filtering. At the same time, the pH values ​​of two adjacent sliding filters are calculated. Lbi-1 pH Lbi With ORP Lbi-1 ORP Lbi The average rate of change of the value over time, K pHi =(pH Lbi -pH Lbi-1 ) / (t i -t i-1 ) and K ORPi =(ORP Lbi -ORP Lbi-1 ) / (t i -t i-1 )value; During the stirring process, when K was monitored pH After a value is >0 for more than 1 minute, K should be monitored. pH and K ORP As the value changes, K is started to be updated in real time. ORP Value and the set threshold K ORPk Comparison, K ORPk The value ranges from -1.2 mV / min to -1.4 mV / min, and A is processed as follows. n The time-segmented mixing process is controlled online. ① When K is detected pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi The absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value of the concentration is reached, the stirrer (31) is turned off immediately to stop the stirring operation; at this time, if the COD concentration in the mixture is detected to be greater than 115 mg / L, the concentration of A is appropriately reduced in the next cycle. n Water inflow Q during the period n Q n The decrease in amount, while satisfying the period A n K appeared during the time-sharing operation pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi The absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk In addition to the absolute value, the COD concentration in the mixed solution must also be less than 115 mg / L; ② When a K greater than zero is detected pH The value changes from large to small to K pH The absolute value is <0.003 min -1 And K ORP When the time-varying curve of the value is still slowly decreasing without any characteristic signal appearing, water can be drawn again from the second concentration water tank (2) through the second concentration water inlet pump (25) and the second concentration water inlet valve (26) during the stirring process, and water is introduced at a rate of (0.03~0.15)Q. n The flow rate is continuously fed into the SBR reactor (5), while K is continuously monitored. pH and K ORP When the value changes, K is monitored pH The value changes from positive to negative, and K is detected within 2 minutes before or after this feature point. ORPi The absolute value > K ORPi-1 The absolute value of K, and K ORPi The absolute value ≥ K ORPk When the absolute value is reached, the second concentration water inlet valve (26) and the second concentration water inlet pump (25) are closed in real time to stop water intake, and the stirrer (31) is closed in real time to stop stirring operation. 5) Short-term aeration operation: After stopping the stirring, the blower (27) and the aeration valve (28) are turned on in real time to aerate the SBR reactor (5). The aeration time t4 is 8~25min. When the set aeration time t4 is reached, the blower (27) and the aeration valve (28) are turned off in real time to stop the aeration operation. 6) Sedimentation: After stopping the aeration operation, the mixture in the SBR reactor (5) is placed in a sedimentation state to achieve mud-water separation; 7) Drainage and sludge removal: When the set sedimentation time t5 is reached, the drain valve (29) is opened in real time to discharge the treated supernatant from the SBR reactor (5) through the drain pipe (13). t5 is 30~70 min. According to the set sludge removal plan, the sludge removal valve (30) is opened in real time to remove sludge through the sludge removal pipe (14). When the set drainage time t6 and sludge removal time t7 are reached, the drain valve (29) and sludge removal valve (30) are closed in real time to stop drainage and sludge removal. t6 is 15~40 min and t7 is 2~15 min. 8) Idle: The SBR reactor (5) is in a standby state where it stops working. When the set idle time is reached, the system will automatically switch to the next cycle of operation.

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