Carbon source dosing and tn regulation method for aao biological tank based on front-end monitoring

Abstract

The application discloses an AAO biological pool carbon source adding and TN regulation method based on front-end monitoring, and the application guarantees the accuracy of front-end data monitoring by monitoring and regulating the front end of the AAO biological pool, calculates the total carbon source adding unit consumption which needs to be increased or reduced by the carbon source adding system in real time through a system algorithm, is provided with a real-time correction algorithm for the total carbon source adding unit consumption, ensures that the effluent TN is stably controlled near the expected value, and can judge whether the carbon source needs to be added, and has the functions of timely early warning and regulation; when facing sewage treatment with a large change range of water quality components, especially in the case that the change range of ammonia nitrogen and nitrate nitrogen in the influent is high, the regulation mode of the internal and external reflux ratios of the method is more accurate, in the case that the low-carbon single ratio of the influent is insufficient to maintain the biological system denitrification, automatic carbon source adding for denitrification is realized, and finally, automatic and accurate control of the effluent TN is realized.

Description

Technical Field

[0001] This invention relates to the field of nitrogen removal technology in AAO biological ponds, and in particular to a method for carbon source addition and TN regulation in AAO biological ponds based on front-end monitoring. Background Technology

[0002] Currently, most municipal wastewater treatment plants employ the AAO (Ammonia-Oxygen-Alternating Current) process. This process involves the removal of nitrogen from wastewater through a three-step reaction of ammonification, nitrification, and denitrification by microorganisms. In the aerobic stage, organic nitrogen compounds are decomposed into ammonia nitrogen by ammonifying bacteria. Then, ammonia nitrogen is further decomposed and oxidized by nitrifying bacteria. First, in the aerobic stage, nitrification occurs through the synergistic action of nitrifying and nitrite-oxidizing bacteria, converting ammonia nitrogen into nitrite and nitrate nitrogen. Under anoxic conditions, denitrification converts nitrate nitrogen into nitrogen gas, which escapes from the water surface and is released into the atmosphere, participating in the natural nitrogen cycle. This significantly reduces nitrogenous substances in the water, lowers the potential hazards of the effluent, and achieves the goal of denitrification from wastewater.

[0003] For example, patent document CN 110182952 A discloses an automatic feedback and adjustment device for the dosage of composite carbon source in the AAO process of municipal wastewater treatment plants. This technical solution feeds back the results to the control system in real time through nitrate nitrogen data and initial online dissolved oxygen data, and sets the control parameters of the PLC based on previous experience data. The program directly calculates the carbon source output flow rate using formulas based on the data of each variable, and can adjust it at any time if a parameter changes. However, this solution does not have the function of calculating the TN of the effluent from the biological tank at the end of the anoxic stage, nor does it have the function of accurately controlling the TN at the preset value, which can easily lead to system regulation lag and instability.

[0004] Patent document CN 116022924 A discloses an in-situ precise biological denitrification wastewater treatment control method. This technical solution places the anoxic zone upstream of the aerobic zone, using internal recirculation to first return sludge from the aerobic zone to the anoxic zone, and then returning a portion of the mixed liquor from the anoxic zone to the anaerobic zone, thereby reducing the impact of nitrate in the returned sludge on anaerobic phosphorus release. A certain amount of process denitrification production data is collected using an online nitrate nitrogen monitor to monitor the nitrate nitrogen concentration at the end of the anoxic and aerobic zones in real time, and to monitor changes in the denitrification rate. However, this technical solution does not provide accurate real-time monitoring of influent nitrate nitrogen, and the organic nitrogen concentration in the biological tank is only estimated. It is only suitable for wastewater treatment plants with stable influent water quality. These two indicators directly affect total nitrogen control; when the fluctuations in influent nitrate nitrogen and organic nitrogen increase, the parameters cannot be corrected in real time to accurately calculate the nitrate and organic nitrogen content, thus resulting in inaccurate control.

[0005] Therefore, the present invention provides a new solution to this problem. Summary of the Invention

[0006] In view of the above situation and to overcome the shortcomings of the existing technology, the purpose of this invention is to provide a method for carbon source addition and TN regulation in AAO biological ponds based on front-end monitoring, so as to solve the above problems existing in the prior art. The specific solution is as follows:

[0007] The method for carbon source addition and TN regulation in AAO biological ponds based on front-end monitoring includes the following steps:

[0008] 1) The total nitrogen (TN) and ammonia nitrogen (A1) in each biological tank were measured using an online total nitrogen monitor and an online ammonia nitrogen monitor, respectively. The nitrate nitrogen (P1) in each biological tank and the nitrate nitrogen (P2) at the end of the anoxic section were measured using an online nitrate nitrogen analyzer, and the measurement data were sent to the carbon source system PLC.

[0009] 2) The carbon source system PLC automatically switches the system algorithm based on the comparison result of the measurement data in step 1) and the system preset threshold H1, and calculates the nitrogen M1 at the end of the anoxic zone other than nitrate nitrogen, i.e.

[0010] When TN-A1-P1≤H1, switch to the simplified algorithm:

[0011] M1=(Q1 A1+Q2 A2+Q3 A3) / (Q1+Q2+Q3)(1)

[0012] Wherein, M1: other nitrogen besides nitrate nitrogen at the end of the anoxic zone, in mg / L;

[0013] Q1: Influent flow rate of the biological tank, in meters. 3 / h;

[0014] Q2: External reflux flow rate of the biological tank, in m³ / s. 3 / h;

[0015] Q3: Flow rate in the biological tank, in m³ / s. 3 / h;

[0016] A1: Ammonia nitrogen value in influent, in mg / L;

[0017] A2: External reflux ammonia nitrogen value, in mg / L;

[0018] A3: Internal reflux ammonia nitrogen value, in mg / L;

[0019] When TN-A1-P1 > H1, switch to the full algorithm:

[0020] M1=(Q1 A1´+Q2 A2+Q3 A3) / (Q1+Q2+Q3)(2)

[0021] Where A1´ = TN-P1, the unit is mg / L;

[0022] 3) The carbon source system PLC controls the nitrogen content (M1) at the end of the anoxic zone (excluding nitrate nitrogen) and the expected total nitrogen (TN) at the biological tank outlet. 预期 The comparison results are fed back to the on-site PLC, specifically:

[0023] If M1 > TN 预期 The feedback is sent to the on-site PLC, which adjusts and controls the flow rate in the biological treatment tank to increase the flow rate. The on-site PLC then feeds back the flow rate in the biological treatment tank to the carbon source system PLC in real time, which in turn determines the relationship between M1 and TN. 预期 The difference, until M1 < TN 预期 ;

[0024] If M1 < TN 预期 The carbon source system PLC combines the terminal nitrate nitrogen (P2) in the anoxic zone with the system's preset TN. 预期 Value, calculate in real time the required reduction value P of nitrate nitrogen at the end of the anoxic section;

[0025] 4) Calculate the required reduction value P of nitrate nitrogen at the end of the anoxic section:

[0026] P = M1 + P2 - TN 预期 (3)

[0027] Wherein, P: the required reduction value of nitrate nitrogen concentration at the end of the anoxic section, in mg / L;

[0028] TN 预期 : Expected control value of total nitrogen at the outlet of the biological treatment pond, in mg / L;

[0029] P2: Measured value of nitrate nitrogen at the end of the anoxic section, in mg / L;

[0030] 5) Calculate the increase or decrease in carbon source consumption C required for a single biological pond. 调 :

[0031] C 调 =P K (Q1+Q2+Q3) / Q1(4)

[0032] Among them, C 调 The value that needs to be increased or decreased for carbon source consumption, in mg / L;

[0033] K: Denitrification ratio;

[0034] 6) Calculate the total carbon source consumption C required to be increased or decreased for the entire carbon source addition system by weighting the influent flow rates of each biological tank according to formula (4). 总调 :

[0035] C 总调 =(C 调1 Q1+C 调2 Q2+...+C 调n Q n ) / (Q1+Q2+...+Q n (5)

[0036] Among them, C 总调 Total carbon source consumption that needs to be increased or reduced, in mg / L;

[0037] C 调1 The carbon source input consumption that needs to be increased or decreased for the first group of biological ponds is expressed in mg / L.

[0038] C 调2 The carbon source input consumption that needs to be increased or decreased in the second group of biological ponds is expressed in mg / L.

[0039] C 调n The carbon source input that needs to be increased or decreased for the nth group of biological ponds, in mg / L;

[0040] Q1: Influent flow rate of the first biological tank, in meters per second (m³). 3 / h;

[0041] Q2: Influent flow rate of the second biological tank, in meters. 3 / h;

[0042] Q n : Influent flow rate of the nth biological tank, in m³ 3 / h;

[0043] 7) Calculate the total carbon source flow rate Q of the carbon source addition system when multiple biological tanks are running in parallel. 总 :

[0044] Q 总 =(C 总 +C 总调 ) (Q1+Q2+...+Qn) / e / 60 / 1000 (6)

[0045] Among them, Q 总 : Total carbon source flow rate of the carbon source dosing system, in L / min;

[0046] C 总: Total initial carbon source consumption, in mg / L;

[0047] e: Carbon source density, in g / ml;

[0048] 8) The carbon source system PLC adjusts the carbon source addition unit consumption C according to overall needs. 总调 Adjust the total carbon source flow Q in real time based on the change in the amount of change. 总 This is to achieve precise carbon source input and precise TN control in the AAO biological pool.

[0049] Preferably, in step 5), the denitrification ratio K is determined by a carbon source denitrification experiment. It is defined as the mass of carbon source required to remove 1 mg of nitrate nitrogen, i.e., the ratio of carbon source addition consumption to the concentration of nitrate nitrogen removed. Specifically, it includes the following steps:

[0050] 2.1) Take an appropriate amount of activated sludge mixture from the anoxic zone as raw water, add nitrate nitrogen standard solution and stir evenly to increase the nitrate nitrogen concentration of the supernatant to 15-20 mg / L;

[0051] 2.2) Take the same amount of raw water in m beakers and stir continuously until the dissolved oxygen is below 0.5 mg / L;

[0052] 2.3) Add carbon sources with different unit consumption to the beakers respectively;

[0053] 2.4) After stirring for a further time T, take the supernatant and measure the concentration of nitrate nitrogen in the supernatant in the beaker;

[0054] 2.5) Calculate the denitrification ratio K based on the experimental results.

[0055] First, the denitrification ratios K1, K2...Km in each beaker are measured using formula (7):

[0056] K 实验 =C / (N0 3原水 -NO 3反应后 (7)

[0057] Then, the average denitrification ratio in each beaker is taken as the actual denitrification ratio K:

[0058] K=(K1+K2+...+Km) / m(8)

[0059] Wherein, K1: the denitrification ratio of the raw water in beaker 1;

[0060] K2: The nitrogen removal ratio of the raw water in beaker 2;

[0061] Km: The nitrogen removal ratio of the raw water in beaker m;

[0062] C: Carbon source addition unit consumption;

[0063] N0 3原水 : Product of nitrate nitrogen concentration in raw water, in mg / L;

[0064] NO 3反应 : Nitrate nitrogen concentration in the supernatant, in mg / L.

[0065] Preferably, the stirring time T in step 2.2) is the actual reaction time in the anoxic zone, i.e., the residence time of the carbon source in the anoxic zone:

[0066] T=V / (Q1+Q2+Q3) (9)

[0067] Where V: effective volume of the hypoxic section, in m³ 3 .

[0068] The beneficial effects of the present invention through the above technical solutions are as follows:

[0069] 1. This invention ensures the accuracy of front-end data monitoring by monitoring and regulating the front end of the AAO biological pond. The system algorithm calculates in real time the total carbon source consumption that needs to be increased or decreased in the overall carbon source addition system. It also has a real-time correction algorithm for the total carbon source consumption, ensuring that the effluent TN is stably controlled near the expected value. It can also determine whether carbon source needs to be added, and has the function of timely early warning and regulation.

[0070] 2. When dealing with wastewater treatment where the composition of influent water varies greatly, especially when the influent ammonia nitrogen and nitrate nitrogen levels are high, this method provides more accurate control over the internal and external reflux ratios. When the low carbon ratio influent is insufficient to maintain the denitrification of the biological system, it enables automatic addition of denitrification carbon sources, ultimately achieving automatic and precise control of effluent TN. Attached Figure Description

[0071] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention, and the embodiments in the accompanying drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0072] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0073] Figure 2 This is a schematic diagram of the structure of the AAO biological pool of the present invention. Detailed Implementation

[0074] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, which are preferred embodiments of the present invention. It should be understood that the described embodiments are merely some embodiments of the present invention, and not all embodiments; it should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0075] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0076] like Figure 1 As shown, the method for carbon source addition and TN regulation in an AAO biological pond based on front-end monitoring includes the following steps:

[0077] 1) The total nitrogen (TN) and ammonia nitrogen (A1) in each biological tank were measured using an online total nitrogen monitor and an online ammonia nitrogen monitor, respectively. The nitrate nitrogen (P1) in each biological tank and the nitrate nitrogen (P2) at the end of the anoxic section were measured using an online nitrate nitrogen analyzer, and the measurement data were sent to the carbon source system PLC.

[0078] 2) The carbon source system PLC automatically switches the system algorithm based on the comparison result of the measurement data in step 1) and the system preset threshold H1, and calculates the nitrogen M1 at the end of the anoxic zone other than nitrate nitrogen, i.e.

[0079] When TN-A1-P1≤H1, switch to the simplified algorithm:

[0080] M1=(Q1 A1+Q2 A2+Q3 A3) / (Q1+Q2+Q3)(1)

[0081] Wherein, M1: other nitrogen besides nitrate nitrogen at the end of the anoxic zone, in mg / L;

[0082] Q1: Influent flow rate of the biological tank, in meters. 3 / h;

[0083] Q2: External reflux flow rate of the biological tank, in m³ / s. 3 / h;

[0084] Q3: Flow rate in the biological tank, in m³ / s. 3 / h;

[0085] A1: Ammonia nitrogen value in influent, in mg / L;

[0086] A2: External reflux ammonia nitrogen value, in mg / L;

[0087] A3: Internal reflux ammonia nitrogen value, in mg / L;

[0088] When TN-A1-P1 > H1, switch to the full algorithm:

[0089] M1=(Q1 A1´+Q2 A2+Q3 A3) / (Q1+Q2+Q3)(2)

[0090] Where A1´ = TN-P1, the unit is mg / L;

[0091] 3) The carbon source system PLC controls the nitrogen content (M1) at the end of the anoxic zone (excluding nitrate nitrogen) and the expected total nitrogen (TN) at the biological tank outlet. 预期 The comparison results are fed back to the on-site PLC, specifically:

[0092] If M1 > TN 预期 The feedback is sent to the on-site PLC, which adjusts and controls the flow rate in the biological treatment tank to increase the flow rate. The on-site PLC then feeds back the flow rate in the biological treatment tank to the carbon source system PLC in real time, which in turn determines the relationship between M1 and TN. 预期 The difference, until M1 < TN 预期 ;

[0093] If M1 < TN 预期 The carbon source system PLC combines the terminal nitrate nitrogen (P2) in the anoxic zone with the system's preset TN. 预期 Value, calculate in real time the required reduction value P of nitrate nitrogen at the end of the anoxic section;

[0094] 4) Calculate the required reduction value P of nitrate nitrogen at the end of the anoxic section:

[0095] P = M1 + P2 - TN 预期 (3)

[0096] Wherein, P: the required reduction value of nitrate nitrogen concentration at the end of the anoxic section, in mg / L;

[0097] TN 预期 : Expected control value of total nitrogen at the outlet of the biological treatment pond, in mg / L;

[0098] P2: Measured value of nitrate nitrogen at the end of the anoxic section, in mg / L;

[0099] 5) Calculate the increase or decrease in carbon source consumption C required for a single biological pond. 调 :

[0100] C 调 =P K (Q1+Q2+Q3) / Q1(4)

[0101] Among them, C 调 The value that needs to be increased or decreased for carbon source consumption, in mg / L;

[0102] K: Denitrification ratio;

[0103] 6) Calculate the total carbon source consumption C required to be increased or decreased for the entire carbon source addition system by weighting the influent flow rates of each biological tank according to formula (4). 总调 :

[0104] C 总调 =(C 调1 Q1+C 调2 Q2+...+C 调n Q n ) / (Q1+Q2+...+Q n (5)

[0105] Among them, C 总调 Total carbon source consumption that needs to be increased or reduced, in mg / L;

[0106] C 调1 The carbon source input consumption that needs to be increased or decreased for the first group of biological ponds is expressed in mg / L.

[0107] C 调2 The carbon source input consumption that needs to be increased or decreased in the second group of biological ponds is expressed in mg / L.

[0108] C 调n The carbon source input that needs to be increased or decreased for the nth group of biological ponds, in mg / L;

[0109] Q1: Influent flow rate of the first biological tank, in meters per second (m³). 3 / h;

[0110] Q2: Influent flow rate of the second biological tank, in meters. 3 / h;

[0111] Q n : Influent flow rate of the nth biological tank, in m³ 3 / h;

[0112] 7) Calculate the total carbon source flow rate Q of the carbon source addition system when multiple biological tanks are running in parallel. 总 :

[0113] Q 总 =(C 总+C 总调 ) (Q1+Q2+...+Qn) / e / 60 / 1000 (6)

[0114] Among them, Q 总 : Total carbon source flow rate of the carbon source dosing system, in L / min;

[0115] C 总 : Total initial carbon source consumption, in mg / L;

[0116] e: Carbon source density, in g / ml;

[0117] 8) The carbon source system PLC adjusts the carbon source addition unit consumption C according to overall needs. 总调 Adjust the total carbon source flow Q in real time based on the change in the amount of change. 总 To achieve precise carbon source input and precise TN control in AAO biological ponds;

[0118] In actual TN control, the carbon source system PLC calculates the required increase or decrease in carbon source consumption for each biological tank based on the parameters within each group of biological tanks. Then, it calculates the total change in carbon source consumption based on the required increase or decrease in carbon source consumption for each group of biological tanks. If the total change in carbon source consumption is positive, the total change in carbon source consumption is added to the initial carbon source consumption to obtain the corrected total carbon source consumption. The corrected carbon source flow rate is then calculated based on the corrected total carbon source flow rate. The frequency of the carbon source dosing pump is increased based on the corrected carbon source flow rate to achieve the corrected flow rate. If the corrected flow rate is not achieved, an additional carbon source pump is activated. If the total change in carbon source consumption is negative, the total change in carbon source consumption is added to the initial carbon source consumption to obtain the corrected total carbon source consumption. The corrected carbon source flow rate is then calculated based on the corrected total carbon source consumption. The frequency of the carbon source dosing pump is decreased based on the corrected carbon source flow rate to achieve the corrected flow rate. If the corrected carbon source consumption is less than 0, the carbon source dosing pump is shut down.

[0119] In the above, the denitrification ratio K in step 5) is determined by the carbon source denitrification experiment. It is defined as the mass of carbon source required to remove 1 mg of nitrate nitrogen, that is, the ratio of carbon source addition consumption to the concentration of nitrate nitrogen removed. Specifically, it includes the following steps:

[0120] 2.1) Take an appropriate amount of activated sludge mixture from the anoxic zone as raw water, add nitrate nitrogen standard solution and stir evenly to increase the nitrate nitrogen concentration of the supernatant to 15-20 mg / L;

[0121] 2.2) Take the same amount of raw water in m beakers and stir continuously until the dissolved oxygen is below 0.5 mg / L;

[0122] 2.3) Add carbon sources with different unit consumption to the beakers respectively;

[0123] 2.4) After stirring for a further time T, take the supernatant and measure the concentration of nitrate nitrogen in the supernatant in the beaker;

[0124] 2.5) Calculate the denitrification ratio K based on the experimental results.

[0125] First, the denitrification ratios K1, K2...Km in each beaker are measured using formula (7):

[0126] K 实验 =C / (N0 3原水 -NO 3反应后 (7)

[0127] Then, the average denitrification ratio in each beaker is taken as the actual denitrification ratio K:

[0128] K=(K1+K2+...+Km) / m(8)

[0129] Wherein, K1: the denitrification ratio of the raw water in beaker 1;

[0130] K2: The nitrogen removal ratio of the raw water in beaker 2;

[0131] Km: The nitrogen removal ratio of the raw water in beaker m;

[0132] C: Carbon source addition unit consumption;

[0133] N0 3原水 : Product of nitrate nitrogen concentration in raw water, in mg / L;

[0134] NO 3反应 : Nitrate nitrogen concentration in the supernatant, in mg / L.

[0135] In the above, the stirring time T in step 2.2) is the actual reaction time in the anoxic zone, that is, the residence time of the carbon source in the anoxic zone:

[0136] T=V / (Q1+Q2+Q3)(9)

[0137] Where V: effective volume of the hypoxic section, in m³ 3 .

[0138] Example 1

[0139] To compare the actual denitrification effects of different carbon sources, we simulated the operating conditions of a biological tank and tested the removal effect of different dosages on nitrate nitrogen in the effluent. Based on the denitrification effect, we selected a high-quality carbon source and formulated this beaker experiment scheme to determine the selection of carbon source and denitrification ratio K.

[0140] Experimental Principle: Biological denitrification refers to the process by which organic nitrogen and ammonia nitrogen in wastewater are converted into nitrogen gas through ammonification, nitrification, and denitrification under the combined action of microorganisms. Carbon source is an indispensable condition for denitrification. In this experiment, different types of carbon sources were added at the same concentrations (50 mg / L, 100 mg / L, and 150 mg / L) under the same influent conditions. The optimal carbon source was selected based on the removal rate and the effluent quality.

[0141] Experimental plan:

[0142] 1. Selection of carbon source concentration and calculation of dosage

[0143] Based on our company's actual production data for a certain month, the highest carbon source consumption was 252 mg / L, the lowest was 32 mg / L, and the monthly average consumption was 101 mg / L. Based on the analysis of actual operation, we determined that the carbon source dosage should be selected at three concentration gradients: 50 mg / L, 100 mg / L, and 150 mg / L. The dosage was calculated based on the carbon source density (obtained by weighing a fixed volume using a graduated cylinder and an electronic balance). The dosages for different carbon sources are shown in Table 1-1 below.

[0144] Table 1-1: Carbon Source Addition Amount

[0145]

[0146] 2. Operating Procedures

[0147] 2.1 Take a bucket of mixed solution from the anoxic section of the biological tank (greater than 20L), and increase its nitrate nitrogen concentration to 19mg / L by adding nitrate nitrogen standard solution or potassium nitrate, sodium nitrate, etc. After stirring, put 1L of the mixed solution into 13 1L beakers (it must be stirred continuously to ensure that the mixed solution is always in a mixed state). One of them is used as raw water to measure the nitrate nitrogen concentration of its supernatant.

[0148] 2.2 The water sample was placed on a six-piece stirrer and stirred, and its DO content was measured by a dissolved oxygen meter.

[0149] 2.3 After the DO is below 0.5 mg / L, add different carbon sources with the same unit consumption (the dosage is shown in Table 1-1) in sequence, and set the stirring speed to 50 rpm.

[0150] 2.4. Stir for 1.5 hours, then take the supernatant and measure the nitrate nitrogen concentration.

[0151] 2.5 Comparison of data.

[0152] 2.6. Based on the test results, conduct multiple verification tests as necessary to ensure the accuracy of the test results.

[0153] 3. Experimental Data

[0154] See Tables 2-1 and 2-2.

[0155]

[0156] Table 2-1: Experimental Results Data Table

[0157] Table 2-2: Experimental Results Data Table

[0158]

[0159] 4. Experimental Conclusions

[0160] 4.1 Under different dosages, the nitrate nitrogen removal rate was best with Exxon, followed by carbon source 3, carbon source 2 was slightly worse, and carbon source 1 was the worst.

[0161] 4.2 Of the four carbon source agents, Exxon has the highest COD equivalent, followed by carbon source 2, while carbon source 3 and carbon source 1 have lower COD equivalents.

[0162] 4.3. Exxon and carbon source 3 have stable denitrification ratios, while carbon source 1 and carbon source 2 have higher denitrification ratios and lower removal rates when added at low dosages.

[0163] 4.4 In summary, the best denitrification effect is achieved by the Exxon carbon source, and its denitrification ratio is determined to be:

[0164] K = (10.4 + 9.9 + 10.9) / 3 = 10.4

[0165] Example 2

[0166] Taking Zhengzhou Airport Economic Zone Minggang Water Co., Ltd. as an example, the AAO biological tank consists of four areas: a pre-anoxic tank, an anaerobic tank, an anoxic tank, and an aerobic tank. The pre-anoxic section has one compartment, the anaerobic section has one compartment, and the anoxic section has five compartments. Each compartment is equipped with a vertical turbine mixer to keep the sludge in suspension and to ensure thorough mixing with the wastewater. The remaining three sections are aerobic tanks. The AAO biological tank and nitrate nitrogen monitoring points are as follows... Figure 2 As shown.

[0167] The initial total unit consumption of carbon source addition, C, is calculated by manually inputting the carbon source density e on the carbon source system PLC. 总 Expected control value of total nitrogen (TN) at the biological pond outlet 预期 The system presets a threshold H1 and, combined with input data from system monitoring equipment, regulates carbon source addition and total nitrogen (TN) in the AAO biological tank. As the influent ammonia nitrogen and nitrate nitrogen in the biological tank continuously change, the carbon source system PLC calculates in real time and corrects the carbon source addition unit consumption every 5 minutes, controlling the nitrate nitrogen value at the end of the anoxic section in real time to ensure that the total nitrogen (TN) at the anoxic section outlet remains near the pre-controlled value.

[0168] The daily TN data of the system platform after one week of continuous operation are as follows:

[0169] Table 3-1: Daily Statistics of Online Monitoring System for Water Pollution Sources

[0170]

[0171]

[0172]

[0173]

[0174]

[0175]

[0176]

[0177]

[0178]

[0179]

[0180]

[0181] Among them, TN was discharged on August 13-14. 预期 The concentration was 11 mg / L, and the total TN in the effluent from August 15th to 19th was [not specified]. 预期 It is 10 mg / L;

[0182] As can be seen from the table above:

[0183] 1. After the carbon source system PLC operates using the carbon source addition and TN control method of this invention, the total nitrogen (TN) in the effluent remains continuously and stably at a certain level. 预期 The target of precisely controlling the total nitrogen in the effluent was achieved by keeping the value near the specified range.

[0184] 2. By comparing the online monitoring values ​​with the manual test values, the absolute error is around 0.5 mg / L, the percentage error is around 5%, and the frequency of manual sampling is lower than the frequency of online proportional sampling, which indicates that the online data is stable and accurate.

[0185] In summary, this invention ensures the accuracy of front-end data monitoring through monitoring and control at the AAO biological tank. The system algorithm calculates in real-time the total carbon source consumption that needs to be increased or decreased in the overall carbon source addition system, and includes a real-time correction algorithm for the total carbon source consumption, ensuring that the effluent TN is stably controlled near the expected value. It can also determine whether carbon source addition is necessary, providing timely early warning and control. When dealing with wastewater treatment with significant variations in influent water quality, especially when influent ammonia nitrogen and nitrate nitrogen levels are high, this method provides more accurate control of the internal and external reflux ratios. Even when a low carbon source ratio in the influent is insufficient to maintain the biological system's denitrification, it achieves automatic addition of denitrification carbon sources, ultimately realizing automatic and precise control of effluent TN.

[0186] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for carbon source addition and TN regulation in an AAO biological pond based on front-end monitoring, characterized in that, Includes the following steps: 1) The total nitrogen (TN) and ammonia nitrogen (A1) in each biological tank were measured using an online total nitrogen monitor and an online ammonia nitrogen monitor, respectively. The nitrate nitrogen (P1) in each biological tank and the nitrate nitrogen (P2) at the end of the anoxic section were measured using an online nitrate nitrogen analyzer, and the measurement data were sent to the carbon source system PLC. 2) The carbon source system PLC automatically switches the system algorithm based on the comparison result of the measurement data in step 1) and the system preset threshold H1, and calculates the nitrogen M1 at the end of the anoxic zone other than nitrate nitrogen, i.e. When TN-A1-P1≤H1, switch to the simplified algorithm: M1=(Q1 A1+Q2 A2+Q3 A3) / (Q1+Q2+Q3)(1) Wherein, M1: other nitrogen besides nitrate nitrogen at the end of the anoxic zone, in mg / L; Q1: Influent flow rate of the biological tank, in meters per second (m³). 3 / h; Q2: External reflux flow rate of the biological tank, in m³ / s. 3 / h; Q3: Flow rate in the biological tank, in m³ / s. 3 / h; A1: Ammonia nitrogen value in influent, in mg / L; A2: External reflux ammonia nitrogen value, in mg / L; A3: Internal reflux ammonia nitrogen value, in mg / L; When TN-A1-P1 > H1, switch to the full algorithm: M1=(Q1 A1´+Q2 A2+Q3 A3) / (Q1+Q2+Q3)(2) Where A1´ = TN-P1, the unit is mg / L; 3) The carbon source system PLC controls the nitrogen content (M1) at the end of the anoxic zone (excluding nitrate nitrogen) and the expected total nitrogen (TN) at the biological tank outlet. 预期 The comparison results are fed back to the on-site PLC, specifically: If M1 > TN 预期 The feedback is sent to the on-site PLC, which adjusts and controls the flow rate in the biological treatment tank to increase the flow rate. The on-site PLC then feeds back the flow rate in the biological treatment tank to the carbon source system PLC in real time, which in turn determines the relationship between M1 and TN. 预期 The difference, until M1 < TN 预期 ; If M1 < TN 预期 The carbon source system PLC combines the terminal nitrate nitrogen (P2) in the anoxic zone with the system's preset TN. 预期 Value, calculate in real time the required reduction value P of nitrate nitrogen at the end of the anoxic section; 4) Calculate the required reduction value P of nitrate nitrogen at the end of the anoxic section: P=M1+P2-TN 预期 (3) Wherein, P: the required reduction value of nitrate nitrogen concentration at the end of the anoxic section, in mg / L; TN 预期 : Expected control value of total nitrogen at the outlet of the biological treatment pond, in mg / L; P2: Measured value of nitrate nitrogen at the end of the anoxic section, in mg / L; 5) Calculate the increase or decrease in carbon source consumption per unit of a single biological pond, C. 调 : C 调 =P K (Q1+Q2+Q3) / Q1(4) Among them, C 调 The value that needs to be increased or decreased for carbon source consumption, in mg / L; K: Denitrification ratio; 6) Calculate the total carbon source consumption C required to be increased or decreased for the entire carbon source addition system by weighting the influent flow rates of each biological tank according to formula (4). 总调 : C 总调 =(C 调1 Q1+C 调2 Q2+...+C 调n Q n ) / (Q1+Q2+...+Q n )(5) Among them, C 总调 Total carbon source consumption that needs to be increased or reduced, in mg / L; C 调1 The carbon source input consumption that needs to be increased or decreased for the first group of biological ponds is expressed in mg / L. C 调2 The carbon source input consumption that needs to be increased or decreased in the second group of biological ponds is expressed in mg / L. C 调n The carbon source input that needs to be increased or decreased for the nth group of biological ponds, in mg / L; Q1: Influent flow rate of the first biological tank, in meters per second (m³). 3 / h; Q2: Influent flow rate of the second biological tank, in meters. 3 / h; Q n : Influent flow rate of the nth biological tank, in m³ 3 / h; 7) Calculate the total carbon source flow rate Q of the carbon source addition system when multiple biological tanks are running in parallel. 总 : Q 总 =(C 总 +C 总调 ) (Q1+Q2+...+Qn) / e / 60 / 1000 (6) Among them, Q 总 : Total carbon source flow rate of the carbon source dosing system, in L / min; C 总 : Total initial carbon source consumption, in mg / L; e: Carbon source density, in g / ml; 8) The carbon source system PLC adjusts the carbon source addition unit consumption C according to overall needs. 总调 Adjust the total carbon source flow Q in real time based on the change in the amount of change. 总 This is to achieve precise carbon source input and precise TN control in the AAO biological pool.

2. The method according to claim 1, characterized in that, In step 5), the denitrification ratio K is determined by a carbon source denitrification experiment. It is defined as the mass of carbon source required to remove 1 mg of nitrate nitrogen, i.e., the ratio of carbon source addition consumption to the concentration of nitrate nitrogen removed. Specifically, it includes the following steps: 2.1) Take an appropriate amount of activated sludge mixture from the anoxic zone as raw water, add nitrate nitrogen standard solution and stir evenly to increase the nitrate nitrogen concentration of the supernatant to 15-20 mg / L; 2.2) Take the same amount of raw water in m beakers and stir continuously until the dissolved oxygen is below 0.5 mg / L; 2.3) Add carbon sources with different unit consumption to the beakers respectively; 2.4) After stirring for a further time T, take the supernatant and measure the concentration of nitrate nitrogen in the supernatant in the beaker; 2.5) Calculate the denitrification ratio K based on the experimental results. First, use formula (7) to measure the denitrification ratios K1, K2...Km in each beaker: K 实验 =C / (N0 3原水 -NO 3反应后 ) (7) Then, the average denitrification ratio in each beaker is taken as the actual denitrification ratio K: K=(K1+K2+...+Km) / m(8) Wherein, K1: the denitrification ratio of the raw water in beaker 1; K2: The nitrogen removal ratio of the raw water in beaker 2; Km: The nitrogen removal ratio of the raw water in beaker m; C: Carbon source addition unit consumption; N0 3原水 : Product of nitrate nitrogen concentration in raw water, in mg / L; NO 3反应 : Nitrate nitrogen concentration in the supernatant, in mg / L.

3. The method according to claim 2, characterized in that, The stirring time T in step 2.4) is the actual reaction time in the anoxic zone, i.e., the residence time of the carbon source in the anoxic zone: T=V / (Q1+Q2+Q3) (9) Where V: effective volume of the hypoxic section, in m³ 3 .

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