CN114132980A

CN114132980A - Short-range intelligent accurate aeration control method, equipment and system for sewage treatment

Info

Publication number: CN114132980A
Application number: CN202210099507.1A
Authority: CN
Inventors: 周华; 袁丁; 袁维芳; 何梓灏; 吴楚辉; 韩燕东; 王亚东; 何玉明; 姚远鹏; 郭俊康
Original assignee: Guangzhou Yangxin Technology Research Co ltd; Guangdong Guangye Environmental Protection Industry Group Co ltd
Current assignee: Guangzhou Yangxin Technology Research Co ltd; Guangdong Guangye Environmental Protection Industry Group Co ltd
Priority date: 2022-01-27
Filing date: 2022-01-27
Publication date: 2022-03-04
Anticipated expiration: 2042-01-27
Also published as: CN114132980B

Abstract

The invention discloses a short-range intelligent accurate aeration control method, equipment and a system for sewage treatment, belonging to the field of sewage treatment, and comprising the steps of obtaining the water inflow, a first total nitrogen value and a first equivalent BOD at the water inlet of a sewage treatment line; setting a target ammonia nitrogen value of the effluent of the aerobic tank; acquiring a second ammonia nitrogen value, a second total nitrogen value and a second equivalent BOD after the effluent of the aerobic tank; calculating the basic air volume according to the difference between the second equivalent BOD and the first equivalent BOD, the difference between the first total nitrogen value and the target ammonia nitrogen value, the difference between the first total nitrogen value and the second total nitrogen value and the water inflow; calculating the correction air quantity according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value and the water inflow; the basic air quantity and the correction air quantity are superposed to calculate the indicated air quantity, aeration is carried out according to the indicated air quantity, the monitored parameters are less than those of a common intelligent aeration model, the correction air quantity is introduced to control the air quantity variation during adjusting the air quantity, the qualified water quality can be maintained, excessive aeration is avoided, the aeration power consumption is reduced, and the activated sludge is protected.

Description

Short-range intelligent accurate aeration control method, equipment and system for sewage treatment

Technical Field

The invention relates to a short-range intelligent accurate aeration control method, equipment and a system for sewage treatment, and belongs to the field of sewage treatment.

Background

The direct production cost of the sewage treatment plant mainly comprises electricity, medicine, mud and repair, and the electricity consumption is the main direct production cost item, wherein a fan used for aeration is the main household of the electricity consumption, and accounts for about 35-55% of the electricity consumption. At present, more sewage treatment plants have the condition of inaccurate and excessive aeration, and the fan is accurately controlled, saves energy and reduces consumption, thereby having larger space.

For the A2O (also called A/A/O technology, namely a biochemical pool comprises an anaerobic pool, an anoxic pool and an aerobic pool in sequence according to the sewage flow direction), the nitrification reaction can be influenced by too low aeration amount. Too high aeration, in addition to high electricity costs, can also result in: firstly, the redundant DO (dissolved oxygen) influences the denitrification of the anoxic tank and the phosphorus release of phosphorus accumulating bacteria in the anaerobic tank through internal and external reflux; secondly, the DO content of the anaerobic tank is too high through external reflux, so that the consumption of a carbon source is increased; and thirdly, the water inlet load is constantly changed, when the water inlet load is low and the aeration rate is high, sludge disintegration can occur due to overexposure, and further the system is unstable.

In order to reduce the power consumption cost on the basis of reaching the effluent standard, a great deal of cost and attention are put into the sewage treatment industry in recent years on the technical development and application effect of accurate aeration, and intelligent aeration becomes a research hotspot in the field.

The DO concentration of dissolved oxygen, which is closely related to the aeration effect, is a crucial research parameter in a plurality of accurate aeration control models and is also taken as the most effective control object. However, the basic modeling method of the DO concentration of the dissolved oxygen is obtained by a large amount of mathematical calculations according to physical and chemical formulas of microorganisms in the biochemical reaction process, the treatment process is relatively complex, and if an accurate DO concentration model is to be achieved, the basic modeling method is very difficult. It is difficult to achieve the dissolved oxygen DO control only with the conventional PID control.

In recent years, an accurate aeration control system based on an activated sludge series model ASMs of International Water Association (IWA) as a core algorithm is developed rapidly, wherein the most representative is an aeration flow control system (AVS) which adopts aeration flow as a control variable and water quality parameters such as dissolved oxygen DO and the like which can influence the aeration flow as auxiliary variables, and the aeration amount required by the system is obtained through the comprehensive arrangement of the established biological treatment module and historical data, so that the dissolved oxygen concentration is predicted. For example, the sewage treatment process optimization and advanced control system prose is based on an international water coordinated activated sludge model ASM2D, besides basic modeling parameters of designed water quantity and quality, historical data, real-time data and the like, the embedded mathematical model comprises models (such as power consumption of a fan and a water pump) for describing the reaction kinetics (carbon oxidation, nitrification, denitrification, phosphorus removal and the like) process of a biological pond, the one-dimensional sedimentation process of a sedimentation tank and important power consumption equipment, and the acquisition of excessive parameters can cause huge testing pressure and overlong time feedback, so that the established accurate aeration model has larger deviation.

In the prior art, a precise aeration control algorithm is complex in modeling and is overstaffed, phosphorus removal control parameters in a model are more, uncontrollable dissolved oxygen internal circulation including a biological phosphorus removal system, a reflux system and the like is included, and monitoring is difficult; and the time interval between feedforward and feedback is long, reaches more than 18 hours, comprises the whole sewage treatment process, has serious lag, can not really realize accurate aeration, and brings inconvenience to the operation of a water plant.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a short-range intelligent accurate aeration control method, equipment and a system for sewage treatment, which monitor important parameters in the sewage treatment, abandon the parameters which are difficult to measure and have low correlation, shorten the time between feedforward and feedback and realize short-range accurate aeration control.

In a first aspect, the invention provides a short-range intelligent accurate aeration control method for sewage treatment, which is suitable for an A2O process, and comprises the steps of obtaining the water inflow, a first total nitrogen value and a first equivalent BOD at the water inlet of a sewage treatment line; setting a target ammonia nitrogen value of the effluent of the aerobic tank; acquiring a second ammonia nitrogen value, a second total nitrogen value and a second equivalent BOD after the effluent of the aerobic tank; calculating the basic air quantity according to the difference between the second equivalent BOD and the first equivalent BOD, the difference between the first total nitrogen value and the target ammonia nitrogen value, the difference between the first total nitrogen value and the second total nitrogen value and the water inflow; calculating correction air quantity according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value and the water inflow; and calculating the indicated air volume by superposing the basic air volume and the corrected air volume, and aerating according to the indicated air volume.

The short-range intelligent accurate aeration control method for sewage treatment can accurately regulate and control the aeration quantity of the aerobic tank on the premise of less monitoring parameters, and avoids excessive aeration.

Optionally, the obtaining of the first equivalent BOD step comprises obtaining a first COD at the influent of the wastewater treatment line and a first substitution ratio, the first equivalent BOD being equal to the first COD multiplied by the first substitution ratio; the step of obtaining the second equivalent BOD comprises the step of obtaining a second COD and a second substitution ratio after the effluent of the aerobic tank, wherein the second equivalent BOD is equal to the second COD multiplied by the second substitution ratio;

the step of obtaining the first substitution ratio comprises the steps of measuring multiple groups of BOD and COD at the first COD sampling position in advance, wherein the first substitution ratio is equal to the average value of the multiple groups of BOD/COD at the first COD sampling position; the step of obtaining the second substitution ratio comprises the step of measuring a plurality of groups of BOD and COD at the second COD sampling position in advance, wherein the second substitution ratio is equal to the average value of a plurality of groups of BOD/COD at the first COD sampling position.

The difference value of BOD of intaking and play water BOD reflects the oxygen demand of getting rid of carbonaceous pollutant, but BOD measuring time is of a specified duration, and COD can the spot test, acquires the substitution relation between the two and just can survey COD and replace surveying BOD, shortens monitoring time, makes the aeration adjustment more timely to it is more accurate.

Optionally, the step of aerating according to the indicated air volume includes obtaining a relationship between a frequency of a fan for aeration air supply and an air volume in advance, substituting the indicated air volume into the relationship between the frequency of the fan for aeration air supply and the air volume to obtain an indicated frequency, and adjusting an operating frequency of the fan to be the indicated frequency.

The frequency and the air quantity of the fan are not strictly linear, the corresponding relation between the frequency and the air quantity of the fan is read, the frequency of the fan is adjusted by utilizing the relation, and the output air quantity can be close to the indicated air quantity.

Optionally, the indication air volume is calculated according to the basic air volume, the correction air volume and a correction coefficient, the correction coefficient includes a desliming coefficient, and the step of generating the desliming coefficient includes obtaining historical data of a sewage treatment line, calculating a remaining desliming factor oxygen demand and a removing desliming factor oxygen demand according to the historical data, and the desliming coefficient is equal to a ratio of the removing desliming factor oxygen demand to the remaining desliming factor oxygen demand.

For a general oxidation ditch, the oxygen demand for sewage treatment = carbon oxygen demand + total kjeldahl nitrogen oxygen consumption-denitrification oxygen saving amount; for the A2O process, the carbon-oxygen-saving amount of the discharged sludge, the total kjeldahl nitrogen-containing oxygen-saving amount of the discharged sludge and the nitrate-containing oxygen consumption of the discharged sludge caused by sludge discharge need to be considered, and actually, the sludge discharge has little influence on the calculation of the oxygen demand of sewage treatment, if the calculation is carried out according to the sewage treatment oxygen demand = the carbon oxygen demand, the carbon-oxygen-saving amount of the discharged sludge + the total kjeldahl nitrogen-containing oxygen-saving amount of the discharged sludge, the denitrification oxygen-saving amount + the nitrate-containing oxygen consumption of the discharged sludge leads to excessive parameters to be monitored, and the discharged sludge is nonlinear, so that the influence of the discharged sludge is considered, the regulation difficulty is reduced, and the desliming coefficient is introduced.

Optionally, the indicated air volume is calculated according to the basic air volume, the correction air volume and a correction coefficient, the correction coefficient includes an oxygen utilization rate, and the generating of the oxygen utilization rate includes obtaining a historical second ammonia nitrogen value, screening out a continuous historical second ammonia nitrogen value with a mean value within a range of 20% -40% of an ammonia nitrogen value specified by an execution standard, recording a corresponding continuous historical time, obtaining a historical basic air volume corresponding to the continuous historical time and a historical actual air volume of a fan, obtaining a plurality of historical basic air volumes and a plurality of historical actual air volumes, and calculating a plurality of continuous oxygen utilization rates according to each historical basic air volume and the corresponding historical actual air volume, where the oxygen utilization rate is a mean value of the plurality of continuous oxygen utilization rates.

Optionally, the basic air volume is calculated according to a difference between the second equivalent BOD and the first equivalent BOD, a difference between the first total nitrogen value and the target ammonia nitrogen value, a difference between the first total nitrogen value and the second total nitrogen value, the water inflow and an accompanying coefficient, wherein the accompanying coefficient comprises a carbon oxidation oxygen demand parameter multiplied by the difference between the second equivalent BOD and the first equivalent BOD, a total Kjeldahl nitrogen oxidation oxygen demand parameter multiplied by the difference between the first total nitrogen value and the target ammonia nitrogen value, and a denitrification oxygen saving parameter multiplied by the difference between the first total nitrogen value and the second total nitrogen value;

the iteration step of the carbon oxidation oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving quantity parameter comprises the steps of obtaining a historical second ammonia nitrogen value, screening a plurality of historical second ammonia nitrogen values meeting the condition by taking the corresponding historical target ammonia nitrogen value +/-0.5 mg/L as a screening condition, recording a plurality of corresponding historical moments, and obtaining the historical water inflow, the historical first total nitrogen value, the historical first equivalent BOD, the historical target ammonia nitrogen value, the historical second total nitrogen value, the historical second equivalent BOD and the historical actual air quantity of the fan, which correspond to the historical moments; changing the values of the carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter by using a test algorithm, recalculating the indication air volume at the corresponding moment by using the changed carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter to obtain virtual indication air volume, calculating the absolute deviation of each virtual indication air volume and the corresponding historical actual air volume, and when the average value of a plurality of absolute deviations is minimum, enabling the carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter at the moment to be the carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter after iteration.

Further, the step of changing the values of the carbon oxide oxygen demand parameter, the total kjeldahl nitrogen oxide oxygen demand parameter and the denitrification oxygen saving parameter by using a test algorithm, and recalculating the indication air volume at the corresponding moment by using the changed carbon oxide oxygen demand parameter, the total kjeldahl nitrogen oxide oxygen demand parameter and the denitrification oxygen saving parameter to obtain a virtual indication air volume, and when the average value of the absolute deviation between the virtual indication air volume and the historical actual air volume is minimum, making the carbon oxide oxygen demand parameter, the total kjeldahl nitrogen oxide oxygen demand parameter and the denitrification oxygen saving parameter at the moment as the carbon oxide oxygen demand parameter, the total kjeldahl nitrogen oxide oxygen demand parameter and the denitrification oxygen saving parameter after iteration, comprises the steps of:

constructing a loss function aiming at the average value of the absolute deviation of the virtual indication air volume and the historical actual air volume;

calculating a minimum value of the loss function by using a gradient descent method;

and taking the carbon oxidation oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter when the minimum value is obtained as the carbon oxidation oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter after iteration.

Optionally, the correction air volume is calculated according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value, the water inflow and the ammonia nitrogen acceleration parameter, and the determination step of the ammonia nitrogen acceleration parameter includes:

when the second ammonia nitrogen value is less than or equal to the target ammonia nitrogen value, the ammonia nitrogen acceleration parameter is 0;

when the second ammonia nitrogen value is greater than the target ammonia nitrogen value and is less than or equal to 50% of the ammonia nitrogen value specified by the execution standard, the ammonia nitrogen acceleration parameter is equal to K;

when the second ammonia nitrogen value is more than 50% of the ammonia nitrogen value specified by the execution standard and less than or equal to 80% of the ammonia nitrogen value specified by the execution standard, the ammonia nitrogen acceleration parameter is equal to 2K;

when the second ammonia nitrogen value is greater than 80% of the ammonia nitrogen value specified by the execution standard, the ammonia nitrogen acceleration parameter is equal to 3K;

and K is an ammonia nitrogen acceleration base number, the iteration step of the ammonia nitrogen acceleration base number comprises the steps of obtaining a historical second ammonia nitrogen value, screening the historical second ammonia nitrogen value by taking the second ammonia nitrogen value which is larger than the target ammonia nitrogen value and smaller than 50% of an ammonia nitrogen value specified by an execution standard as a screening condition, recording corresponding continuous historical moments, obtaining historical basic air quantity, historical actual air quantity of a fan, historical water inflow and a historical target ammonia nitrogen value which correspond to the continuous historical moments, and calculating the K according to the historical water inflow, the difference between the historical actual air quantity and the historical basic air quantity and the difference between the historical second ammonia nitrogen value and the historical target ammonia nitrogen value.

In a second aspect, the present invention provides an electronic device comprising a processor and a memory, said memory storing computer readable instructions which, when executed by said processor, perform the method of short-range intelligent precise aeration control for wastewater treatment according to the first aspect.

In a third aspect, the present invention provides a sewage treatment system, which adopts A2O process, utilizes a fan to blow air to aerate an aerobic tank, and comprises a console, a water inlet flow meter, a water inlet total nitrogen determinator and a water inlet COD analyzer which are arranged at the water inlet of a sewage treatment line, and an ammonia nitrogen determinator, a water outlet total nitrogen determinator and a water outlet COD analyzer which are arranged after the water outlet of the aerobic tank, wherein the console comprises:

the setting module is used for setting a target ammonia nitrogen value of the effluent of the aerobic tank;

the first acquisition module is used for acquiring the water inflow measured by the water inflow flowmeter, the first total nitrogen value measured by the water inflow total nitrogen measuring instrument and the water inflow COD measured by the water inflow COD instrument and converting the water inflow COD into a first equivalent BOD;

the second acquisition module is used for acquiring a second ammonia nitrogen value measured by the ammonia nitrogen measuring instrument, a second total nitrogen value measured by the effluent total nitrogen measuring instrument and an effluent COD measured by the effluent COD, and converting the effluent COD into a second equivalent BOD;

a basic air volume calculating module, configured to calculate a basic air volume according to a difference between the second equivalent BOD and the first equivalent BOD, a difference between the first total nitrogen value and the target ammonia nitrogen value, a difference between the first total nitrogen value and the second total nitrogen value, and the water inflow;

the correction air volume calculation module is used for calculating correction air volume according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value and the water inflow;

and the indicating module is used for superposing the basic air quantity and the correction air quantity to calculate the indicating air quantity and indicating the blower blast according to the indicating air quantity.

The invention has the beneficial effects that: the short-range intelligent accurate aeration control method for sewage treatment simplifies and calculates some factors with low correlation with the oxygen demand of sewage treatment, has less parameters to be monitored than a common intelligent aeration model, measures BOD of inlet and outlet water by an indirect method, can shorten the measurement time, introduces air volume change quantity when correcting air volume control and adjusting air volume, can maintain qualified water quality, does not perform excessive aeration, realizes accurate aeration, is favorable for reducing aeration power consumption and protecting activated sludge.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

FIG. 1 is a schematic structural diagram of a sewage treatment system according to an embodiment of the present application.

FIG. 2 is a comparison graph of theoretical aeration and actual aeration air volume before modification of a pilot sewage treatment plant.

FIG. 3 is a graph of the relationship between the fan air volume and the frequency of a pilot sewage treatment plant.

Fig. 4 is a graph of operational data of a pilot sewage treatment plant after modification.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Referring to fig. 1, a short-range intelligent precise aeration control method for sewage treatment, which is suitable for A2O process, comprises the steps of obtaining water inflow Q, a first total nitrogen value and a first equivalent BOD at the water inlet of a sewage treatment line; setting a target ammonia nitrogen value of the effluent of the aerobic tank; acquiring a second ammonia nitrogen value, a second total nitrogen value and a second equivalent BOD after the effluent of the aerobic tank; calculating the basic air volume according to the difference between the second equivalent BOD and the first equivalent BOD, the difference between the first total nitrogen value and the target ammonia nitrogen value, the difference between the first total nitrogen value and the second total nitrogen value and the water inflow; calculating the correction air quantity according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value and the water inflow; and superposing the basic air volume and the corrected air volume to calculate the indicated air volume, and aerating according to the indicated air volume. The basic air volume is calculated after some unimportant or nonlinear parameters are ignored in the embodiment of the application, the sewage treatment relates to various biochemical reactions, the theoretical calculation cannot be completely consistent with the real situation, and therefore correction air volume is introduced for correction; on the other hand, because some parameters are ignored for the convenience of monitoring, the correction air quantity can compensate the deviation caused by the part to a certain extent.

The sewage treatment oxygen demand = carbon oxygen demand-carbon oxygen-saving amount of the discharged sludge + total kjeldahl nitrogen oxygen consumption-total kjeldahl nitrogen oxygen-saving amount of the discharged sludge-denitrification oxygen-saving amount + nitrate oxygen-consuming amount of the discharged sludge, the influence of the discharged sludge on the sewage treatment oxygen demand is small, and the corrected air volume comprises monitoring of a second ammonia nitrogen value, so that the problem that the calculated basic air volume is inaccurate after the discharged sludge is ignored can be solved to a certain extent. After the sludge is neglected, parameters needing to be measured are greatly reduced, and the monitored parameters are all continuously changed and are easy to calculate. The total Kjeldahl nitrogen oxygen consumption is linearly related to a total Kjeldahl nitrogen value removed by the oxidation ditch, the total Kjeldahl nitrogen value removed by the oxidation ditch = an inlet water total Kjeldahl nitrogen value-an outlet water total Kjeldahl nitrogen value, but the inlet water total Kjeldahl nitrogen value and the outlet water total Kjeldahl nitrogen value can not be measured by an instrument in the prior art, so that the method is replaced by subtracting the outlet water ammonia nitrogen value from the inlet water total nitrogen value. Generally, the ammonia nitrogen value at the tail end of the oxidation ditch in the A2O process is almost equal to the ammonia nitrogen value at the total effluent, so the measuring point of the second ammonia nitrogen value can be at the effluent of an aerobic tank and the total effluent of a sewage treatment line. Preferably, in order to shorten the feedback time, the measuring point of the second ammonia nitrogen value is arranged at the effluent of the aerobic tank.

The difference between the second equivalent BOD and the first equivalent BOD reflects the carbon oxygen demand, the difference between the first total nitrogen value and the target ammonia nitrogen value reflects the total Kjeldahl nitrogen oxygen consumption, and the difference between the first total nitrogen value and the second total nitrogen value reflects the denitrification oxygen saving amount. The calculation form of the oxygen demand of the sewage treatment is as follows:

(ii) a Formula 1

Wherein:

q is the water inflow at the water inlet of the sewage treatment line, which is the total water inflow within 1 hour of automatic collection;

-a first equivalent BOD;

-a second equivalent BOD;

-a first total nitrogen value;

-a target ammonia nitrogen value;

-a second total nitrogen value;

-a second ammonia nitrogen value;

-oxygen demand, including basic oxygen demand and supplemental oxygen demand, in kg/h;

1000-water inflow in m-th plantation, wherein the unit collected by each monitoring instrument is mg/L and the unit is needed to be transformed;

1.47-the time for each organic matter in the sewage to be oxidized and decomposed is about one hundred days, in order to shorten the detection time, the general biochemical oxygen demand is represented by the oxygen consumption of a detected water sample at 20 ℃ within five days, and is called the biochemical oxygen demand for five days, which is called BOD5 for short, and the research shows that the BOD5 of the domestic sewage is about equal to 68% of the oxygen consumption of the complete oxidative decomposition, so that 1/0.68=1.47 is temporarily taken;

4.57-Oxidation of 1g NH₄Total oxygen consumption in N reaction of 2 × 32 (O relative atomic mass)/14 (N relative atomic mass) =4.57 g;

2.86-coefficient of oxygen recovery from nitrates by denitrification.

The step of obtaining the first equivalent BOD comprises the steps of obtaining a first COD and a first substitution ratio at the water inlet of the sewage treatment line, wherein the first equivalent BOD is equal to the first COD multiplied by the first substitution ratio; the step of obtaining the second equivalent BOD comprises the steps of obtaining a second COD and a second substitution ratio at the water inlet of the sewage treatment line, wherein the second equivalent BOD is equal to the second COD multiplied by the second substitution ratio;

the step of obtaining the first substitution ratio comprises the steps of measuring multiple groups of BOD and COD at the first COD sampling position in advance, wherein the first substitution ratio is equal to the average value of the multiple groups of BOD/COD at the position; the step of obtaining the second substitution ratio comprises the step of measuring a plurality of groups of BOD and COD at the second COD sampling position in advance, wherein the second substitution ratio is equal to the average value of the plurality of groups of BOD/COD at the position.

COD (chemical oxygen demand) and BOD (biochemical oxygen demand) do not have absolute formula relation calculation, but for a sewage treatment plant, the sewage is treated by the sewage which is produced daily in the local, strains for sewage treatment do not rapidly change, and the ratio of BOD and COD at the same position in a sewage treatment line in a short period (calculated according to months) hardly changes greatly, so that the substitution ratio can be determined in advance, and the COD which can be determined quickly replaces the BOD which is measured for a long time.

The form of the calculation becomes:

(ii) a Formula 2

Wherein:

-a first COD;

-a second COD;

a-first substitution ratio;

b-second substitution ratio.

In practical situations, oxygen in the air cannot be completely dissolved into water, and oxygen dissolved into water cannot be completely reacted, so that although the correction air volume can compensate for the actual deviation to a certain extent, in order to make the calculation more accurate, the oxygen utilization rate should be introduced.

The indicated air volume is calculated according to the basic air volume, the correction air volume and the correction coefficient, the correction coefficient comprises an oxygen utilization rate, the generation step of the oxygen utilization rate comprises the steps of obtaining a historical second ammonia nitrogen value, taking the average value within the range of 20% -40% of the ammonia nitrogen value specified by the execution standard as a screening condition, screening continuous historical second ammonia nitrogen values, recording corresponding continuous historical moments, obtaining historical basic air volume corresponding to the continuous historical moments and historical actual air volume of the fan, obtaining a plurality of historical basic air volumes and a plurality of historical actual air volumes, calculating according to the historical basic air volumes and the corresponding historical actual air volumes to obtain a plurality of continuous oxygen utilization rates, and the oxygen utilization rate is the average value of the plurality of continuous oxygen utilization rates.

Neglecting the influence of temperature change, the calculation form of the indicated air volume is as follows:

(ii) a Formula 3

In the formula:

indicating the amount of wind in m³/h；

0.21-percentage of oxygen in air;

1.33-20 ℃ oxygen density in kg/m³；

-oxygen utilization.

In the

above formulas

1 and 2

The pure oxygen flow is adopted, and air is used for actual aeration, so the oxygen content in the air needs to be considered in the formula 3. But oxygen in the air can not be completely dissolved in water, and the oxygen dissolved in the water can not be completely reacted, so that the oxygen utilization rate is introduced. For example, the oxygen utilization rate is not considered when air is supplied, the correction air volume becomes very large in order to make the effluent reach the standard, and the difference between the basic air volume and the actually required air volume is very large; historical actual air volume = historical basic air volume + historical corrected air volume, in order to make the basic air volume closer to the actual required air volume and make the corrected air volume smaller, the corrected air volume should not be considered when calculating the oxygen utilization rate, that is, the oxygen utilization rate at a certain moment = historical actual air volume/historical basic air volume at a certain moment,

the average value of the oxygen utilization rate at a plurality of time points.

Preferably, the correction factor further comprises a desliming factor, and the step of generating the desliming factor comprises obtaining historical data of the sewage treatment line, and calculating a retained desliming factor oxygen demand and a desliming factor oxygen demand according to the historical data, wherein the desliming factor is equal to the ratio of the desliming factor oxygen demand to the retained desliming factor oxygen demand. Therefore, the influence of discharged mud is considered, and the regulation and control difficulty is reduced.

The calculation form of the indicated air volume is changed into:

(ii) a Formula 4

The basic air volume is as follows:

(ii) a Formula 5

The correction air volume is as follows:

(ii) a Formula 6

Wherein:

-basic air volume;

-basic air volume;

-coefficient of desliming.

The desliming coefficient is adjusted only when the desliming condition is greatly changed or abnormally changed, and if the desliming equipment is maintained, the acquisition range of historical data is the data between the time before the current maintenance of the desliming equipment and the time after the last maintenance of the desliming equipment. The desliming coefficient = oxygen demand for desliming factor removal/oxygen demand for remaining desliming factor retention, wherein the oxygen demand for remaining desliming factor can be calculated according to a method provided by the design specification for outdoor drainage GB 50014-one 2006, and the historical data is a parameter used for calculating the oxygen demand according to the design specification for outdoor drainage GB 50014-one 2006. In other words, the embodiment of the application needs to measure the non-linear parameters in daily operation, but is only used for adjusting the desliming coefficient after the maintenance of the desliming equipment and not used for controlling the indicated air volume in real time, and the monitored parameters for controlling the indicated air volume in real time are all parameters which are linearly changed and easy to measure.

The invention mainly takes the ammonia nitrogen in the supernatant of the effluent of the biochemical tank as the most core precise control parameter instead of COD, DO and other parameters, and the main reasons are as follows:

firstly, in the denitrification process, nitrobacteria only account for 5-10% of zoogloea, the number of heterotrophic bacteria is still in an absolute position, meanwhile, the proliferation and metabolism of the heterotrophic bacteria are fast, the proliferation of autotrophic bacteria is slow originally, and the removal speed of COD is far faster than that of ammonia nitrogen due to different states of the heterotrophic bacteria and the autotrophic bacteria; compared with the long-term operation condition, the ammonia nitrogen does not always reach the standard when the effluent COD reaches the standard, the ammonia nitrogen does not reach the standard when the effluent COD does not reach the standard, but the effluent COD also reaches the standard when the effluent ammonia nitrogen reaches the standard, so that the ammonia nitrogen is selected as a judgment standard of the biochemical tank water quality treatment effect and a control basis to be more suitable.

Secondly, Dissolved Oxygen (DO) represents the dissolved amount of oxygen in water, and is substantially the residual dissolved oxygen amount in sewage treatment, for the time-delay aeration process, a lower DO interval can also ensure better dissolved oxygen effect and removal efficiency, and for the CASS process (cyclic activated sludge process, A2O process concept), a high DO operation condition is required, so that the selection of data is not constant and the sewage quality treatment effect cannot be linearly reflected by using DO as an adjusting parameter under different processes or water inlet and outlet quality conditions, and the adjustment interval is too large and is too frequent, so that the stability of the aeration equipment is reduced. If the south sewage is oily and has high temperature, the DO is lower, and if the dissolved oxygen is controlled to be 1-2mg/L, excessive aeration is inevitably caused.

Total Kjeldahl Nitrogen (TKN) includes organic nitrogen and ammonia nitrogen. Organic nitrogen can be decomposed by hydrolysis to ammonia and generate ammonia nitrogen, and the process is ammoniation. The amination does not change the valence to the nitrogen atom and no redox reaction occurs. Therefore, 4.57kg of oxygen required by oxidizing 1kg of ammonia nitrogen is adopted to calculate the oxygen amount required by TKN reduction, namely the total Kjeldahl nitrogen oxygen consumption is reflected by the difference between the first total nitrogen value and the target ammonia nitrogen value.

The step of aeration according to the indicated air quantity comprises the steps of acquiring the relation between the frequency of a fan used for aeration air supply and the air quantity in advance, substituting the indicated air quantity into the relation between the frequency of the fan used for aeration air supply and the air quantity to obtain the indicated frequency, and adjusting the working frequency of the fan to be the indicated frequency. This is because the fan frequency and the air volume are not strictly linear, and the output air volume can be made close to the indicated air volume by reading the correspondence between the fan frequency and the air volume and adjusting the fan frequency using the correspondence.

The specific steps of obtaining the relationship between the frequency of the fan used for aeration air supply and the air quantity are as follows, adjusting the fan to output at different frequencies, obtaining the actual air quantity of the fan, and fitting a regression equation of the air quantity with respect to the frequency. The output frequency of the fan can be calculated by substituting the indicated air quantity into the regression equation. The actual air volume of the fan can be obtained by measurement, and some fans with real-time air volume display can directly read the air volume displayed by the fans; the regression equation is preferably a quadratic equation, and may be a polynomial function.

The method can enable the actual air quantity of the fan to be close to the indicated air quantity, the indicated air quantity is calculated according to the monitored parameters, the monitoring result has the possibility of fluctuation up and down, nobody can know the real substance concentration of each point of the sewage treatment line, so the calculated indicated air quantity is only the theoretically required air quantity, and has a point difference with the real situation, the intelligent aeration aims to avoid excessive aeration on the premise of qualified water quality and avoid the large fluctuation of aeration quantity, the point is realized, the corrected air quantity needs to be reduced as much as possible, the accuracy of the basic air quantity is improved as much as possible, and the accompanying coefficient is introduced for the purpose.

The basic air volume is calculated according to the difference between the second equivalent BOD and the first equivalent BOD, the difference between the first total nitrogen value and the target ammonia nitrogen value, the difference between the first total nitrogen value and the second total nitrogen value, the water inflow and the accompanying coefficients, wherein the accompanying coefficients comprise a carbon oxidation oxygen demand parameter multiplied by the difference between the second equivalent BOD and the first equivalent BOD, a total Kjeldahl nitrogen oxidation oxygen demand parameter multiplied by the difference between the first total nitrogen value and the target ammonia nitrogen value, and a denitrification oxygen saving quantity parameter multiplied by the difference between the first total nitrogen value and the second total nitrogen value.

The basic air volume is changed into (limited by typesetting, divided into three items, and the same items can be merged during calculation to reduce the operation times):

(ii) a Formula 7

Wherein:

-a carbon oxidation oxygen demand parameter;

-total kjeldahl nitrogen oxidation oxygen demand parameter;

-denitrification oxygen saving quantity parameter.

The iteration step of the carbon oxidation oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving quantity parameter comprises the steps of obtaining a historical second ammonia nitrogen value, taking a corresponding historical target ammonia nitrogen value +/-0.5 mg/L as a screening condition, screening a plurality of historical second ammonia nitrogen values meeting the condition, recording a plurality of corresponding historical moments, and obtaining a plurality of groups of historical data corresponding to the historical moments, wherein each group of historical data comprises historical water inflow, a historical first total nitrogen value, a historical first BOD equivalent, a historical target ammonia nitrogen value and a historical second total ammonia nitrogen valueNitrogen value, historical second equivalent BOD and historical actual air quantity of the fan. Changing the values of the carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxide oxygen demand parameter and the denitrification oxygen saving parameter by using a trial algorithm, wherein only two decimal parts are reserved for all the three parameters, recalculating the indicated air volume at the corresponding moment by using the changed carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxide oxygen demand parameter and the denitrification oxygen saving parameter to obtain a virtual indicated air volume (not the indicated air volume which is executed once, so called virtual), calculating a virtual indicated air volume by using one group of historical data, calculating the absolute deviation of the virtual indicated air volume and the corresponding historical actual air volume, namely subtracting the absolute value of the difference of the corresponding historical actual air volume from the virtual indicated air volume, obtaining a plurality of absolute deviations by using a plurality of groups of historical data, calculating the average value of the absolute deviations, and when the average value of the absolute deviation of the virtual indicated air volume and the historical actual air volume is the smallest, enabling the carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxide oxygen demand parameter and the denitrification oxygen saving parameter at the moment to be the carbon oxide oxygen demand parameter after iteration The total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving quantity parameter. Wherein, the parameters of the oxygen demand for carbon oxidation, the total Kjeldahl nitrogen oxidation and the denitrification oxygen saving amount in the initial operation are all 1.00, and the step length of each trial calculation is 0.01 in the later trial calculation. Mathematically, there are six anchoring sequences for the three accompanying parameters, but in practice the carbon oxygen demand and total kjeldahl nitrogen oxygen consumption always have a greater effect on the indicated air flow than on the denitrification oxygen saving, and therefore only two trial calculation sequences are included: (1) k is a radical of₁-k₂-k₃；（2）k₂-k₁-k₃And finally, selecting an order with the minimum average value of the absolute deviation.

In addition to trial-and-error algorithms for defining step sizes, trial-and-error algorithms using gradient descent are also possible, such as:

constructing a loss function according to the average value of the absolute deviation of the virtual indicated air volume and the historical actual air volume;

Similarly, the ammonia nitrogen acceleration parameter capable of self-iteration can be introduced to correct the air quantity so that the indicated air quantity is closer to the actually required air quantity.

The corrected air volume is:

(ii) a Formula 8

The indicated air volume becomes:

(ii) a Formula 9

Wherein:

-ammonia nitrogen acceleration parameters.

The correction air volume is calculated according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value, the water inflow and the ammonia nitrogen acceleration parameter, and the determination step of the ammonia nitrogen acceleration parameter comprises the following steps:

when the second ammonia nitrogen value is larger than the target ammonia nitrogen value and is less than or equal to 50% of the ammonia nitrogen value specified by the execution standard, the ammonia nitrogen acceleration parameter is equal to K;

and the iteration step of the ammonia nitrogen acceleration base number comprises the steps of obtaining a historical second ammonia nitrogen value, screening the historical second ammonia nitrogen value by taking the second ammonia nitrogen value which is larger than the target ammonia nitrogen value and smaller than 50% of the ammonia nitrogen value specified by the execution standard as a screening condition, recording a corresponding historical moment, obtaining historical basic air quantity, historical actual air quantity, historical inlet water quantity and historical target ammonia nitrogen value which correspond to the historical moment, and calculating to obtain the K according to the historical inlet water quantity, the difference between the historical actual air quantity and the historical basic air quantity and the difference between the historical second ammonia nitrogen value and the historical target ammonia nitrogen value.

As mentioned above, the historical actual air volume = the historical basic air volume + the historical corrected air volume, the difference between the historical actual air volume and the historical basic air volume is the historical corrected air volume, K can be calculated by substituting the difference between the historical intake water volume, the historical second ammonia nitrogen value and the historical target ammonia nitrogen value into equation 6, and if the oxygen utilization rate is not considered, K is calculated

Is 1; if the desliming factor is not considered, then

Is 1.

The application provides an electronic device, including: a processor and a memory interconnected and communicating with each other via a communication bus and/or other form of connection mechanism, the memory storing a computer program executable by the processor, the processor executing the computer program when the computing device is running to perform the method of any of the alternative implementations of the above embodiments to perform the following functions: acquiring the water inflow Q, a first total nitrogen value and a first equivalent BOD of the water inlet of the sewage treatment line; setting a target ammonia nitrogen value of the effluent of the aerobic tank; acquiring a second ammonia nitrogen value, a second total nitrogen value and a second equivalent BOD after the effluent of the aerobic tank; calculating the basic air volume according to the difference between the second equivalent BOD and the first equivalent BOD, the difference between the first total nitrogen value and the target ammonia nitrogen value, the difference between the first total nitrogen value and the second total nitrogen value and the water inflow; calculating the correction air quantity according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value and the water inflow; and superposing the basic air quantity and the correction air quantity to calculate the indicated air quantity, and instructing the fan to aerate according to the indicated air quantity. The Memory may be implemented by any type of volatile or nonvolatile Memory device or combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic Memory, flash Memory, magnetic disk or optical disk.

Referring to fig. 1, the present application further provides a sewage treatment system, which uses A2O process and utilizes a blower to blow air to aerate an aerobic tank, the system includes a console, a water inlet flow meter, a water inlet total nitrogen measuring instrument and a water inlet COD instrument which are arranged at the water inlet of a sewage treatment line, and an ammonia nitrogen measuring instrument, a water outlet total nitrogen measuring instrument and a water outlet COD instrument which are arranged after the water outlet of the aerobic tank, the console includes:

the basic air volume calculating module is used for calculating the basic air volume according to the difference between the second equivalent BOD and the first equivalent BOD, the difference between the first total nitrogen value and the target ammonia nitrogen value, the difference between the first total nitrogen value and the second total nitrogen value and the water inflow;

the air quantity correction calculation module is used for calculating the air quantity according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value and the water inflow;

and the indicating module is used for superposing the basic air quantity and correcting the air quantity to calculate the indicating air quantity and indicating the fan blast according to the indicating air quantity.

In the A2O process, the process after the oxidation ditch has little influence on the nitrogen concentration, and the ammonia nitrogen determinator, the effluent total nitrogen determinator and the effluent COD (chemical oxygen demand) determinator can be arranged at any position after the aerobic tank, such as the water outlet of the aerobic tank, the water outlet of a secondary sedimentation tank, the water outlet of a deep filter (deep treatment in figure 1) or the total effluent (disinfection effluent in figure 1). Preferably, the ammonia nitrogen determinator, the effluent total nitrogen determinator and the effluent COD (chemical oxygen demand) instrument are arranged at the effluent position of the aerobic tank, compared with the case that the ammonia nitrogen determinator, the effluent total nitrogen determinator and the effluent COD instrument are arranged at the total effluent, the time of parameter difference of front and back monitoring can be shortened by 7 hours, and the nitrogen content is not influenced basically by treatment after the aerobic tank, so that equipment for measuring the total nitrogen and the COD of the effluent can move forwards.

Example of the implementation

The sewage treatment plant in Guangdong is constructed according to the A/A/O process, and has the foundation of modification according to the invention. The water inlet and outlet standards of the sewage plant are as follows:

TABLE 1 quality of influent water

TABLE 2 effluent quality

A comparison graph of the theoretical aeration air volume and the actual aeration air volume of the plant is obtained by combining the laboratory data of the plants 2020.8.1-2021.1.31, the actual air supply record and the theoretical air supply volume measurement and is shown in figure 2.

The reductive pollutants (COD, BOD, ammonia nitrogen and the like) in the effluent are well controlled and far better than the standard requirements. Obtaining theoretical air supply quantity according to a theoretical air supply quantity calculation method, and analyzing the difference relation with the actual air supply quantity to obtain:

(1) the theoretical air supply volume and the actual air supply volume basically fluctuate in a certain range in a crossed manner, the presentation with ammonia nitrogen as an indication index is good, the change trends in the period of 2020.8.1-2020.9.31 are similar, and the quantification of the basic part (basic air volume in the model) of the air supply volume can be basically guided by a theoretical air supply volume calculation rule (according to the outdoor drainage design specification GB 50014-2006).

(2) Most of theoretical air supply amount is lower than actual air supply amount in 2020.10.1-2021.1.31 period, and under the condition of theoretical excess, the ammonia nitrogen is presented well. It is worth noting that the theoretical air supply rate is larger than the actual air supply rate, such as 2 times of 10 months, 3 times of 11 months and 4 times of 12 months later, the ammonia nitrogen index is still in the extremely safe range, which indicates that the theoretical air supply rate still has the floating margin.

(3) The fluctuation of the theoretical air supply amount proves that the air supply amount is calculated completely according to the theory (the design specification GB 50014-2006) of outdoor drainage. The air volume fluctuation is large, and the situations of frequent adjustment and overlarge adjustment amplitude in a short period may occur.

The plant is provided with two oxidation ditches, three fans supply air to a main pipeline in a centralized manner, and the main pipeline is divided into two paths of aeration tanks submerged in the two oxidation ditches for aeration. This original setting of factory is in the flowmeter of the department of intaking, the COD appearance of intaking, sets up the play water COD appearance, the play water total nitrogen apparatus of total water department, sets up two ammonia nitrogen apparatus at two oxidation ditch water departments respectively, and other instruments that are used for measuring other parameters, for example oxidation ditch mud concentration meter, these parameters need not be used to this embodiment model, no longer lists one by one.

The model of the fan is a TURBOMAX air suspension fan, real-time air volume can be directly displayed, the motor adopts a permanent magnet brushless high-speed direct-connected motor and a variable frequency speed control system, the working efficiency of a common alternating current motor is in a higher interval of SV75% -100%, and the reactive loss is higher by nearly 15%; the interval with higher working efficiency of the permanent magnet brushless high-speed direct-connected motor is 20% -100%, and reactive loss is close to zero. The fan adopts frequency conversion regulation, additional pressure loss can not be generated, the energy-saving effect is obvious, and the fan is suitable for occasions with wide regulation range and frequent operation under low load. When the rotating speed of the fan is reduced and the air volume is reduced, the air pressure is changed greatly, the air volume adjusting range SV 50% -100% is normal, and when the adjusting SV (fan frequency) is less than 50% and the output pressure of the air suspension fan is less than the feedback resistance of the pipeline, the air suspension fan is caused to vibrate and stop; therefore, the air volume range SV of a single fan can be set to be 55-100% for safe and stable operation.

During transformation, a water inlet total nitrogen measuring instrument and a console are additionally arranged at a water inlet, the used instrument and a fan are connected to the console, and a program capable of operating the method is implanted into the console. The program includes the following operation models:

(ii) a Formula 10

Wherein, because the plant has two oxidation ditches,

the larger of the two ammonia nitrogen measuring instruments is taken. All measuring instruments measure once every two hours, and the air quantity is adjusted once every two hours.

The frequency, air quantity and power data of the three fans of the plant are regulated and recorded as the following table.

TABLE 3 relationship table of fan frequency, air quantity and power in the plant

The relationship between the actual air volume and the frequency by regression of a quadratic equation is shown in fig. 3. Obtaining the relationship between the air volume y and the frequency x of the No. 1 fan as follows: y = -0.0016x²+ 0.4754 x-4.1429; the relationship between the air volume y and the frequency x of the No. 2 fan is as follows: y = -0.005x²+ 1.05 x-27; the relationship between the air volume y and the frequency x of the No. 3 fan is as follows: y = -0.0036x²+ 0.9186 x-26.429. It should be noted that the unit of the ordinate in fig. 3 is cubic meters per minute, and the unit of the indicated air volume in equation 10 is cubic meters per hour, that is, the indicated air volume in equation 10 needs to be divided by 60 before being substituted into a unitary quadratic equation to obtain the frequency that the fan should adjust.

As shown in table 4, according to the analysis of BOD and COD data of the first half year of the plant transformation, BOD and COD are replaced by average ratio (inlet water BOD/inlet water COD =0.45, i.e., a =0.45, outlet water BOD/outlet water COD =0.25, i.e., b = 0.25), and then the ratio is manually measured once per month and the average ratio is calculated again.

TABLE 4 COD ratio of influent and effluent

In order to ensure the accuracy of the calculation model, the correction coefficient, the accompanying coefficient and the ammonia nitrogen acceleration value are preferably determined in the following sequence.

1) Determining the desliming coefficient: when the primary anchoring is performed, the accompanying coefficient is equal to 1, the ammonia nitrogen acceleration parameter is equal to 0, and the oxygen utilization rate is 1. In table 5, in combination with the effective data of the first half of the transformation, if the sludge discharge factors (that is, the factors for oxygen saving of discharged sludge, total kjeldahl nitrogen oxygen saving of discharged sludge, and nitrate nitrogen oxygen consumption of discharged sludge) are removed in the theoretical calculation, there are cases where the calculation of the blast volume is too high when the sludge discharge factors are removed, and the calculation of the blast volume is too low when the sludge discharge factors are not removed.

TABLE 5 calculation procedure for desliming factor removal and retention

Theoretical blast volume of the oxidation ditch (removing desliming factor, calculating model k as above₁-k₄Is 1, k₆Calculated for the case of 0) and the theoretical blast volume (retaining the desliming factor, calculated according to the outdoor drainage design specification GB 50014-2006) is about 1.647. Therefore, temporarily use k₅The value of =1.647 is included in the model calculation instead of all the formulae relating to the desliming factor.

The desliming coefficient needs to be adjusted only in the following cases: the long-term desliming condition in the factory has great change or abnormal change, such as the condition that desliming equipment cannot be deslimed after being maintained. The collection range of the historical data is the data between the time before the desliming equipment is maintained and the time after the desliming equipment is maintained. The method is the same as for the primary anchoring, i.e. k₁-k₄Is 1, k₆Calculating the theoretical blast volume (off) at 0A desliming factor) to the theoretical blast volume (retaining the desliming factor).

2) Determining the oxygen utilization rate: let k₁-k₃Is 1, k₅Is 1.647, k₆And (3) obtaining a historical second ammonia nitrogen value, screening out continuous historical second ammonia nitrogen values within 48 hours by taking the average value within the range of 1mg/L-2mg/L as a screening condition, recording corresponding continuous historical moments, obtaining historical basic air volume and historical actual air volume of the fan corresponding to the continuous historical moments, and substituting the historical basic air volume and the historical actual air volume into the model shown in the following table.

TABLE 6 oxygen utilization in two oxidation ditches of a certain plant

This factory has two oxidation ditches, by the unified blast air of three fans, has the amount of wind distribution problem, how the amount of wind distributes and relates to a plurality of factors such as two oxidation ditches size relation, pipeline overall arrangement, and this application does not discuss, directly follows the distribution proportion before this factory reforms transform, No. 1 oxidation ditch amount of wind: oxidation ditch air volume No. 2 = 1: 2, the ammonia nitrogen values of the effluent of the two oxidation ditches can be close. As shown in Table 6, in the past data, data within a period of continuous 48 hours are screened, the average ammonia nitrogen value of the effluent of the oxidation ditch No. 1 is 1.35mg/L, the average ammonia nitrogen value of the effluent of the oxidation ditch No. 2 is 1.23mg/L, the data meet the screening conditions, the dissolved oxygen efficiency corresponding to each moment of each oxidation ditch is calculated, the average value is calculated, and the average value is obtained to obtain the average value of the continuous oxygen utilization rate, wherein the oxidation ditch No. 1 is 0.220, and the oxidation ditch No. 2 is 0.131. Combining the air volume distribution relationship:

(ii) a Formula 11

Calculate to obtain k₄= 0.151. The factory has two oxidation ditches, and the unified air supply needs to calculate the air volume distribution relation, if the factory has only one oxidation ditch or the fan and the oxidation ditch have one-to-one correspondence relation, the calculation formula 11 is not needed. For example, if the pilot-modified plant had only oxidation ditch No. 1, noneOxidation channel number 2, then k₄=0.220。

Oxygen utilization needs to be adjusted only in the following cases: the aeration mode or the aeration equipment in the factory is greatly changed or abnormally changed, such as replacement of a fan, addition of the fan and modification of an air supply pipeline. The acquisition range of historical data such as the historical second ammonia nitrogen value, the historical basic air volume, the historical actual air volume and the like is the data between the time before the aeration equipment is changed and the time after the aeration equipment is changed last time. The method is anchored for the same time for the first time, namely, the historical second ammonia nitrogen value which meets the condition and is continuous for 48 hours and the corresponding air volume data are screened, and k is made₁-k₃Is 1, k₅After determination, k₆At 0, the following formula is used for calculation:

(ii) a Formula 12

Wherein:

-historical base air volume;

-historical actual air volume.

3) Three adjoint coefficients are determined: determining k₄And k₅Screening data with a second ammonia nitrogen value of 1mg/L-2mg/L, trial calculating by using a computer, wherein the step length is 0.01 each time, calculating the average value of the absolute deviation of the historical basic air volume and the historical actual air volume by regression to minimize the average value of the absolute deviation, and calculating the average value of the absolute deviation of the historical basic air volume and the historical actual air volume of the fan to be 0.8625m for carrying out the year, wherein k is₁The value is 0.96 and k₂Values of 1.08, k₃The value is 0.94.

The automatic iteration is carried out once every month along with the coefficient, the collection range of the historical data is the last month, and k needs to be determined firstly₄、k₅And let k be₆Is 0, automatically screening data of 1.5mg/L +/-0.5 mg/L according to the target ammonia nitrogen value of 1.5mg/LTrial calculation of k by different precedence order₁-k₃Substituting into the model to calculate the average minimum value of the historical basic air volume and the historical actual air volume absolute deviation, and obtaining k₁-k₃. And (4) calculating an implantable gradient descent algorithm, wherein the reconstruction case is calculated by using a common trial algorithm.

k₁-k₅When re-anchoring, k must be made₆=0, i.e. anchored by the base air volume, k₆Only correct if k₆The variation is large, which indicates that the deviation of the basic air quantity and the actually required air supply quantity is large, so that the ammonia nitrogen acceleration parameter is required to be greatly corrected. Anchoring with basic air quantity to make basic air quantity close to actually required air supply quantity and avoid k₁-k₃Followed by k₆The large-amplitude fluctuation avoids the frequency adjustment of the fan, and is beneficial to the stability of the effluent quality.

4) Determining ammonia nitrogen acceleration parameters: and when the primary anchoring is performed, the target ammonia nitrogen value of the plant is 1.5mg/L, the moment when the 1.5mg/L < the historical second ammonia nitrogen value is less than or equal to 2.5mg/L is recorded, the corresponding air volume at the moment is recorded, and the difference between the historical actual air volume and the historical basic air volume is calculated to obtain the historical actual corrected air volume.

K₆Calculated using the following formula:

(ii) a Formula 13

Wherein:

the historical actual corrected air volume.

Calculated k₆=2.5。

When the second ammonia nitrogen value is smaller than the target ammonia nitrogen value, the ammonia nitrogen acceleration parameter is 0;

when the second ammonia nitrogen value is larger than the target ammonia nitrogen value and is smaller than 50% of the ammonia nitrogen value specified by the execution standard, the ammonia nitrogen acceleration parameter is equal to 2.5;

when the second ammonia nitrogen value is more than 50% of the ammonia nitrogen value specified by the execution standard and less than 80% of the ammonia nitrogen value specified by the execution standard, the ammonia nitrogen acceleration parameter is equal to 5;

and when the second ammonia nitrogen value is greater than 80% of the ammonia nitrogen value specified by the execution standard, the ammonia nitrogen acceleration parameter is equal to 7.5.

The ammonia nitrogen acceleration parameter is automatically iterated once every two hours, the acquisition range of historical data is the first two hours, and k needs to be determined firstly₁-k₅The method is the same as for the first anchoring.

The intelligent aeration effect is shown in figure 4 after the aeration air quantity is controlled by the system for several months. As can be seen from the combination of FIG. 4, the influence of the average ammonia nitrogen in the oxidation ditch (the average value of the second ammonia nitrogen values in the two oxidation ditches) and the total nitrogen index of the inlet water is basically consistent, and the actual condition that the main component of the total nitrogen of the inlet water is ammonia nitrogen is met.

The water amount is increased by about 18.3% in 2021 (1 month-11 months) compared with 2020, the water amount is increased by 13.8% in 2021 from 8 months to 12 months (data is collected to 12 months), the average ton water power consumption is about 0.05 kw.h/ton water in 2021, compared with 0.0536 kw.h/ton water in 9-11 months in 2020, the ton water power consumption is reduced by about 7.54% in 9-11 months in 2021 after automatic control is realized.

The water power consumption per ton in 1-8 months in 2020 is 0.071 kw.h/ton water, the water power consumption per ton in 9-11 months in 2020 is 0.0536 kw.h/ton water, and the water power consumption per ton decreases by about 24.7% after the water amount increases; similarly, the power consumption per ton of water 8 months before 2021 is 0.068 kw.h/ton of water (similar to 2020), while the power consumption per ton of water is reduced by about 27.1% after automatic control is realized, which indicates that the intelligent aeration should have better energy-saving potential for plants with larger water amount.

By utilizing the intelligent accurate aeration control system, the effluent index can stably reach the standard (the standard reaching rate is 100 percent), and the ammonia nitrogen target value can be controlled in a relatively concentrated range: (1) under the same condition, the unit total reducing matter aerobic energy consumption is better after automatic operation, the oxygen utilization efficiency is higher and more accurate, and the efficiency is improved by about 11.72 percent; (2) under the condition that the inlet water reducing substances are low, the low air volume interval can be automatically matched, and 18.84% of air volume can be averagely saved; (3) under the condition of complex water inflow, the air quantity can be measured and calculated in time, and accelerated correction can be performed during abnormal deviation, so that the stability and less deviation of the effluent quality are improved, and the effluent stability is improved from the original worst less than 70% to 100% stability; (4) under the condition that the aeration is not excessive and stably reaches the standard, the method can be accurately controlled in a relatively centralized range, has high energy consumption utilization efficiency and strong matching property (the difference with a historical data measured value under the same working condition is 0.83 percent), can achieve the purpose of stabilizing and reaching the standard of the effluent quality and basically accords with the target value setting.

The system establishes a short-range aeration control process model, simplifies the original full-flow, complex and lagging automatic aeration modeling into short-range section modeling, has short feedback time and rapid reaction, eliminates a large amount of nonlinear interference values, and has better universality. It is expressed in the following aspects:

(1) the traditional method of controlling the air volume by means of DO single data and a simple mode with poor matching performance are abandoned; the internal circulation of dissolved oxygen such as biological phosphorus removal, sludge reflux, nitrification and denitrification and the like is removed, ammonia nitrogen at the water outlet of the biochemical tank is added as a feedback parameter and a control parameter, the control parameter of the intelligent aeration control system is ensured to be limited in an aerobic nitrification phosphorus absorption reaction section, a large number of interference parameters are reduced, and the modeling is easy and accurate.

(2) The general accurate aeration technology can not solve the problem of detecting the ammonia nitrogen index of mixed sludge supernatant in mixed liquid, so the signal used for controlling can only pass through DO and air volume, which leads to a large amount of forward traceability calculation work, not only delays the control reaction speed, but also has low accuracy of forward traceability calculation, and brings great disadvantage to the matching of aeration volume and actual situation. And the filter is additionally arranged on the sampling head in the transformation, so that the real and accurate data of the ammonia nitrogen index detected in the sludge mixed liquor can be directly obtained, the accurate oxygen demand can be rapidly determined (predicted) according to the water quality of the inlet water, and the inlet water is immediately put into reaction, so that the timeliness effect is greatly improved.

(3) The ammonia nitrogen at the water outlet of the biochemical tank is a feedback parameter and a control parameter, namely, a feedback signal is moved forward, the feedback of the general precise aeration technology is obtained at the total water outlet, and the feedback of the system can be obtained at the water outlet of the biochemical tank, so that the response time of feedback deviation correction is reduced by several hours.

(4) The universality is high, the intelligent aeration control system is accurate and easy to control due to the fact that a large number of parameters are complex and difficult to monitor and reduce, the requirement on field personnel is low, and the intelligent aeration control system is easy to popularize to different sewage plants.

In the description of the present specification, reference to the terms "one embodiment," "certain embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

1. A short-range intelligent accurate aeration control method for sewage treatment is suitable for an A2O process and is characterized by comprising the steps of obtaining the water inflow, a first total nitrogen value and a first equivalent BOD at the water inlet of a sewage treatment line; setting a target ammonia nitrogen value of the effluent of the aerobic tank; acquiring a second ammonia nitrogen value, a second total nitrogen value and a second equivalent BOD after the effluent of the aerobic tank; calculating the basic air quantity according to the difference between the second equivalent BOD and the first equivalent BOD, the difference between the first total nitrogen value and the target ammonia nitrogen value, the difference between the first total nitrogen value and the second total nitrogen value and the water inflow; calculating correction air quantity according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value and the water inflow; and calculating the indicated air volume by superposing the basic air volume and the corrected air volume, and aerating according to the indicated air volume.

2. The short-range intelligent precision aeration control method for wastewater treatment according to claim 1, wherein said obtaining of a first equivalent BOD comprises obtaining a first COD and a first substitution ratio after the effluent of said aerobic tank, said first equivalent BOD being equal to said first COD multiplied by said first substitution ratio; the obtaining of the second equivalent BOD step includes obtaining a second COD at the influent of the wastewater treatment line and a second substitution ratio, the second equivalent BOD being equal to the second COD multiplied by the second substitution ratio;

the step of obtaining the first substitution ratio comprises the steps of measuring multiple groups of BOD and COD at the first COD sampling position in advance, wherein the first substitution ratio is equal to the average value of the multiple groups of BOD/COD at the first COD sampling position; the step of obtaining the second substitution ratio comprises the step of measuring a plurality of groups of BOD and COD at the second COD sampling position in advance, wherein the second substitution ratio is equal to the average value of the plurality of groups of BOD/COD at the second COD sampling position.

3. The short-range intelligent precise aeration control method for sewage treatment according to claim 1, wherein the step of aeration according to the indicated air volume comprises obtaining the relationship between the frequency and the air volume of a fan for aeration air supply in advance, substituting the indicated air volume into the relationship between the frequency and the air volume of the fan for aeration air supply to obtain the indicated frequency, and adjusting the operating frequency of the fan to be the indicated frequency.

4. The short-range intelligent precise aeration control method for wastewater treatment according to claim 1, wherein the indicated air volume is calculated from the base air volume, the correction air volume and a correction factor, the correction factor comprising a desliming factor, and the step of generating the desliming factor comprises obtaining historical data of the wastewater treatment line, calculating a retained desliming factor oxygen demand and a desliming factor oxygen demand from the historical data, and the desliming factor being equal to a ratio of the desliming factor oxygen demand to the retained desliming factor oxygen demand.

5. The short-range intelligent precise aeration control method for wastewater treatment according to claim 1, wherein the indicated air volume is calculated according to the basic air volume, the correction air volume and a correction coefficient, the correction factor comprises an oxygen utilization rate, and the generating step of the oxygen utilization rate comprises the steps of obtaining a historical second ammonia nitrogen value, taking the average value within the range of 20-40% of the ammonia nitrogen value specified by the execution standard as a screening condition, screening out continuous historical second ammonia nitrogen values, recording corresponding continuous historical moments, obtaining historical basic air quantity and historical actual air quantity of a fan corresponding to the continuous historical moments, obtaining a plurality of historical basic air quantities and a plurality of historical actual air quantities, and calculating to obtain a plurality of continuous oxygen utilization rates according to the historical basic air volume and the corresponding historical actual air volume, wherein the oxygen utilization rate is the average value of the plurality of continuous oxygen utilization rates.

6. The short-range intelligent precise aeration control method for wastewater treatment according to claim 1, wherein the basic air volume is calculated from a difference between the second equivalent BOD and the first equivalent BOD, a difference between the first total nitrogen value and the target ammonia nitrogen value, a difference between the first total nitrogen value and the second total nitrogen value, the water inflow, and accompanying coefficients including a carbon oxidation oxygen demand parameter multiplied by a difference between the second equivalent BOD and the first equivalent BOD, a total Kjeldahl nitrogen oxidation oxygen demand parameter multiplied by a difference between the first total nitrogen value and the target ammonia nitrogen value, and a denitrification oxygen saving quantity parameter multiplied by a difference between the first total nitrogen value and the second total nitrogen value;

the iteration step of the carbon oxidation oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving quantity parameter comprises the steps of obtaining a historical second ammonia nitrogen value, screening a plurality of historical second ammonia nitrogen values meeting the condition by taking the corresponding historical target ammonia nitrogen value +/-0.5 mg/L as a screening condition, recording a plurality of corresponding historical moments, and obtaining the historical water inflow, the historical first total nitrogen value, the historical first equivalent BOD, the historical target ammonia nitrogen value, the historical second total nitrogen value, the historical second equivalent BOD and the historical actual air quantity of the fan, which correspond to the historical moments; changing the values of the carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter by using a test algorithm, recalculating the indication air volume at a plurality of corresponding moments by using the changed carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter to obtain virtual indication air volume, calculating the absolute deviation of each virtual indication air volume and the corresponding historical actual air volume, and enabling the carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter at the moment to be the carbon oxide oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter after iteration when the average value of the absolute deviations is minimum.

7. The short-range intelligent precise aeration control method for sewage treatment according to claim 6, wherein the step of changing the values of the carbon oxide oxidation oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter by using a test algorithm, and recalculating the indication air volume at the corresponding time by using the changed carbon oxide oxidation oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter to obtain a virtual indication air volume, and when the average value of the absolute deviation of the virtual indication air volume and the historical actual air volume is minimum, making the carbon oxide oxidation oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter at the time as the carbon oxide oxidation oxygen demand parameter, the total Kjeldahl nitrogen oxidation oxygen demand parameter and the denitrification oxygen saving parameter after iteration comprises:

8. The short-range intelligent precise aeration control method for sewage treatment according to claim 1, wherein the correction air volume is calculated according to the difference between the second ammonia nitrogen value and the target ammonia nitrogen value, the water inlet volume and ammonia nitrogen acceleration parameters, and the ammonia nitrogen acceleration parameters are determined by the steps of:

9. An electronic device comprising a processor and a memory, wherein the memory stores computer readable instructions which, when executed by the processor, perform the method of short-range intelligent precise aeration control for wastewater treatment of any of claims 1-8.

10. The utility model provides a sewage treatment system, adopts A2O technology, utilizes the fan blast air aeration in good oxygen pond, its characterized in that, includes the control cabinet, sets up the flowmeter of intaking, the total nitrogen apparatus of intaking, the COD appearance of intaking in the sewage treatment line department of intaking, sets up at the ammonia nitrogen apparatus, the total nitrogen apparatus of play water, the COD appearance of play water behind good oxygen pond effluent, the control cabinet includes: