Method for accurate dosing of phosphorus removal reagent in coagulation process unit in sewage treatment

Abstract

The present application relates to the technical field of water treatment, and discloses a method for accurate dosing of phosphorus removal reagent in a coagulation process unit in sewage treatment, which obtains a curve of phosphorus removal reagent dosing rules through a small test, corrects the curve with statistical results of treatment effects after production application, and finally obtains an accurate dosing control curve and a relationship formula of the phosphorus removal reagent. According to the total phosphorus concentration of the influent and the set total phosphorus concentration target value, the corresponding dosing coefficient is found on the corresponding curve, and the amount of the phosphorus removal reagent to be dosed is calculated. Through the statistics of production application results, according to the relationship between the actual total phosphorus concentration of the effluent and the set total phosphorus concentration target value, the 90% quantile of the total phosphorus concentration of the effluent under the same dosing coefficient is taken, the curve of the dosing coefficient and the total phosphorus concentration of the effluent is corrected, and the corrected relationship formula is obtained. The dosing of the phosphorus removal reagent is guided according to the formula, and accurate dosing is realized.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and specifically to a method for precise dosing of phosphorus removal agents in the coagulation process unit of wastewater treatment. Background Technology

[0002] Phosphorus is a crucial indicator in wastewater treatment. Traditional wastewater treatment plants often rely on experience or fixed dosages for phosphorus removal, leading to waste or inadequate phosphorus removal. With increasingly stringent environmental regulations, standards for phosphorus discharge in wastewater are becoming more stringent. Furthermore, the diverse sources of wastewater and the large fluctuations in phosphorus content necessitate more scientific and precise dosing methods to adapt to varying wastewater qualities, reduce operating costs, and ensure stable discharge compliance. At the same time, indiscriminate dosing can result in excessive reagent residues, causing secondary pollution and harming the ecological environment. Therefore, the need for precise dosing technology has emerged. Summary of the Invention

[0003] This invention provides a method for precise dosing of phosphorus removal agents in the coagulation process unit of wastewater treatment. The method involves obtaining a curve of phosphorus removal agent dosing pattern through small-scale tests, statistically analyzing the treatment effect after production application, and using the statistical results to correct the curve. Finally, a precise dosing control curve and relationship formula for phosphorus removal agents are obtained, thus achieving precise dosing.

[0004] The technical solution of the present invention is to provide a method for precise dosing of phosphorus removal agents in the coagulation process unit of wastewater treatment, comprising the following steps: S1. Take the effluent from other tanks at the front end of the coagulation process unit in the wastewater treatment process as samples, and prepare multiple groups of water samples with different total phosphorus concentrations and concentration gradients. Each group of water samples is repeated multiple times. S2. Set multiple dosage coefficients for each group of multiple water samples in S1. Calculate the amount of phosphorus removal agent to be added for each water sample based on the total phosphorus concentration of the water sample and the different dosage coefficients. Add the corresponding phosphorus removal agent, mix and add coagulant aid, let stand after reaction, and detect the total phosphorus concentration of the supernatant. S3. Using the total phosphorus concentration in the supernatant of each water sample as the abscissa and the addition coefficient as the ordinate, curve fitting is performed to obtain the curve formula and corresponding coefficient of determination for each water sample. S4. Based on the total phosphorus concentration in the influent of the coagulation process unit to be added, select the curve in S3 that is closest to the total phosphorus concentration in the influent, set the target value of the total phosphorus concentration in the effluent of the coagulation process unit, and calculate the required dosage of phosphorus removal agent. S5. Based on the actual total phosphorus concentration C in the effluent of the coagulation process unit. 实际 The target total phosphorus concentration in the effluent, C 目标 Relationship, taking the same addition coefficient C 实际 The 90th percentile, corrected for the curve of dosing coefficient versus total phosphorus concentration in effluent, when C 实际 With C目标 The absolute value of the difference divided by C 目标 If the result is less than or equal to 20%, the curve will not be corrected. This curve will be used as the final corrected relationship formula to guide the addition of phosphorus removal agents.

[0005] Optionally, the wastewater treatment process includes a coarse screen, an influent pumping station, a fine screen, an aerated grit chamber, a medium sedimentation tank, an AAO biological treatment tank, a secondary sedimentation tank, a high-efficiency sedimentation tank, a denitrification filter, and a disinfection tank; wherein the high-efficiency sedimentation tank is a coagulation process unit.

[0006] Optionally, in S1, the effluent from the secondary sedimentation tank and the influent from the biological treatment tank are taken. The effluent from the secondary sedimentation tank is not filtered, while the influent from the biological treatment tank is filtered. The total phosphorus concentration of each is measured. The filtered influent from the biological treatment tank is added to the effluent from the secondary sedimentation tank to prepare a water sample with a higher total phosphorus concentration. Tap water is added to the effluent from the secondary sedimentation tank to prepare a water sample with a lower total phosphorus concentration, so as to obtain a water sample with a concentration gradient.

[0007] Optionally, the total phosphorus concentration range of the water samples to be configured can be adjusted according to the total phosphorus concentration range of the effluent from the secondary sedimentation tank over the past year. At the same time, the difference in total phosphorus concentration between the water samples of each gradient can be reduced as needed, and the number of water samples can be increased.

[0008] Optionally, the phosphorus removal agent is polyferric sulfate, and the coagulant is anionic PAM.

[0009] Optionally, the dosing coefficient is between 1 and 4, and there is a gradient change between adjacent dosing coefficients.

[0010] Optionally, when fitting curves in S3, set the trendline format and select the trendline option whose coefficient of determination is closest to 1 corresponding to the formed curve formula to obtain the curve and the corresponding relationship formula.

[0011] Optionally, the target value for total phosphorus concentration in the effluent of S4 is taken as 30-50% of the upper limit of the standard.

[0012] Optionally, before correction in S5, the total phosphorus concentration, dosage, and flow rate data of the coagulation process unit influent and effluent are detected multiple times over a period of time, and C is continuously taken under the same dosage coefficient. 实际 The 90th percentile was used to correct the curve of the dosing coefficient versus the total phosphorus concentration in the effluent.

[0013] This invention also relates to the application of the method in the precise dosing of phosphorus removal agents in the coagulation process unit of urban wastewater treatment.

[0014] The present invention has the following beneficial effects: 1. The present invention provides a method for precise dosing of phosphorus removal agents in the coagulation process unit of wastewater treatment. Using the total phosphorus concentration in the effluent of the coagulation process unit as the independent variable and the phosphorus removal agent dosage coefficient as the dependent variable, a relationship model is established between the total phosphorus concentration in the wastewater after phosphorus removal and the phosphorus removal agent dosage coefficient. Simultaneously, the relationship model for different influent concentrations is studied, and the dosage is adjusted in a timely manner according to the effluent conditions to ensure stable effluent compliance and optimization of agent dosage. This achieves precise dosing, saving on phosphorus removal agents while ensuring treatment effectiveness.

[0015] 2. In studying the relationship between the total phosphorus concentration in the effluent of the coagulation process unit and the dosage coefficient, this invention also considers the phosphorus concentration of the wastewater before phosphorus removal. Using effluent from other tanks upstream of the coagulation process unit as samples, water samples with different total phosphorus concentrations are prepared. The curves of the effluent total phosphorus concentration versus the dosage coefficient for influent samples with different total phosphorus concentrations are studied. This allows for the selection of the curve closest to the influent total phosphorus concentration of the coagulation process unit during later applications, resulting in more accurate results.

[0016] 3. The present invention also provides a method for correcting curve formulas, which is directly verified and corrected using production data, resulting in a high degree of fit with actual production applications and better performance. Attached Figure Description

[0017] Figure 1 The curve showing the relationship between the total phosphorus concentration and the addition coefficient of sample 1 in Example 1 is shown.

[0018] Figure 2 The curve showing the relationship between the total phosphorus concentration and the addition coefficient in the small-scale test water sample 2 of Example 1 is shown.

[0019] Figure 3 The curve showing the relationship between the total phosphorus concentration and the addition coefficient of water sample 3 in Example 1 is shown.

[0020] Figure 4 The curve showing the relationship between the total phosphorus concentration and the addition coefficient of water sample 4 in Example 1 is shown.

[0021] Figure 5 This is the modified curve showing the relationship between total phosphorus concentration and dosage coefficient in Example 5. Detailed Implementation

[0022] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials used in the following examples are commercially available products.

[0023] The water samples, phosphorus removal agents (PFS), and production and application data used in the following examples were obtained from the Phase II project of the Chengbei Wastewater Treatment Plant in Lu'an City, Anhui Province (hereinafter referred to as "Lu'an Chengbei Phase II Wastewater Treatment Plant"). The main wastewater treatment process is as follows: The system consists of a coarse screen and influent pump station, a fine screen and aerated grit chamber, a medium sedimentation tank, an AAO (Aerated Oxygenation and Aeration) filter, a secondary sedimentation tank, a high-efficiency sedimentation tank, a denitrification filter, and a disinfection tank. The high-efficiency sedimentation tank is a coagulation process unit. The following research focuses on the high-efficiency sedimentation tank.

[0024] The phosphorus removal agent used below is polyferric sulfate (PFS), prepared as a solution with an iron content of 11.0 wt% and a density of 1.45 g / ml.

[0025] The specific methods for precise dosing of phosphorus removal agents in high-efficiency sedimentation tanks for wastewater treatment include the following: 1) After settling, the supernatant of the effluent from the aerated grit chamber was collected, and the total phosphorus concentration was measured to be 2.54 mg / L. After passing through the aerated grit chamber, most particulate matter in the wastewater is removed, and settling further reduces suspended solids, thus eliminating the need for wastewater filtration. The effluent from the secondary sedimentation tank was collected, and the total phosphorus concentration was measured to be 1.31 mg / L. Four groups of water samples with total phosphorus concentrations of 2.0 mg / L, 1.5 mg / L, 1.0 mg / L, and 0.5 mg / L were prepared using water from different sources and tap water. Each group of water samples was divided into seven 500 ml portions, for a total of 28 water samples.

[0026] 2) Through theoretical calculations, when the dosage coefficient of the phosphorus removal agent PFS (11% iron content) is 3, and the total phosphorus in the wastewater is 1g, 49g of PFS (11% iron content) needs to be added. When the dosage coefficient changes, the required mass of PFS (11% iron content) changes proportionally. Based on a water sample volume of 500ml and the total phosphorus concentration, the mass of total phosphorus in each water sample is calculated. The required mass of PFS (11% iron content) per water sample is calculated for dosage coefficients of 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0. The volume of PFS (11% iron content) required per water sample is then converted based on the density of the PFS (11% iron content) used.

[0027] 3) After adding the appropriate volume of PFS to each water sample, stir rapidly at a speed of 100-200 rpm for 2 minutes. Then add the coagulant aid (anionic PAM) at a dosage of 1 mg / L, and stir slowly at a speed of 30-60 rpm for 20 minutes. After stirring, let it stand for half an hour, take the supernatant, and measure the total phosphorus concentration.

[0028] 4) List the data obtained from coagulation experiments at the same influent total phosphorus concentration in a table (such as Excel or WPS), with the effluent total phosphorus concentration as the x-axis and the dosage coefficient as the y-axis. Each water sample will have 7 coordinate points on the axis. By setting the trend line format, select the trend line option whose R-squared value (coefficient of determination) corresponding to the resulting curve formula is closest to 1, resulting in 4 curves and their corresponding relationship formulas. Input the logical relationship of the 4 curves into the control software in code form to achieve automated calculation.

[0029] 5) In production operation, select the curve closest to the total phosphorus concentration in the influent of the high-efficiency sedimentation tank. If the total phosphorus concentration in the influent equals the median of the total phosphorus concentrations corresponding to the two curves, select the curve with the higher influent concentration. By setting the target value for the total phosphorus concentration in the effluent, the corresponding dosing coefficient is found on the curve through automated calculation. Based on the influent flow rate, total phosphorus concentration in the influent, target value for the total phosphorus concentration in the effluent, and PFS (11% iron content) density, combined with the dosing coefficient, calculate the required volume of PFS (11% iron content) to be added, and achieve precise dosing of PFS (11% iron content) through the frequency conversion control of the dosing pump.

[0030] 6) Record the influent flow rate, total phosphorus concentration in the influent and effluent of the high-efficiency sedimentation tank, and PFS (11% iron content) dosage for one month, using the total phosphorus concentration detection frequency as the unit, usually once every 2 hours. Based on the relationship between the actual effluent total phosphorus concentration and the set target value of effluent total phosphorus concentration, take the 90th percentile of the actual effluent total phosphorus concentration under the same dosage coefficient, correct the curve of dosage coefficient and effluent total phosphorus concentration, and obtain the corrected relationship formula.

[0031] 7) Replace the formula relationship corresponding to the curve in step (5) with the formula relationship corresponding to the modified curve, and repeat steps (5) and (6).

[0032] 8) After multiple curve corrections, if the absolute value of the difference between the actual effluent total phosphorus concentration and the set target value of effluent total phosphorus concentration is divided by the set target value of effluent total phosphorus, and the deviation is less than or equal to 20%, the curve is no longer corrected. The curve in step (6) is replaced with this curve to obtain the final corrected relationship formula. The addition of phosphorus removal agents is guided by this formula to achieve precise dosing.

[0033] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention.

[0034] Example 1: Small-scale test to determine the dosing curve and relationship formula Small-scale test water samples 1 and 2 with total phosphorus concentrations of 2.0 mg / L and 1.5 mg / L were prepared using water samples from an aerated grit chamber and a secondary sedimentation tank, respectively. The volume of the aerated grit chamber water sample in each small-scale test water sample was recorded as V1, and the volume of the secondary sedimentation tank water sample was recorded as V2. Small-scale test water samples 3 and 4 with total phosphorus concentrations of 1.0 mg / L and 0.5 mg / L were prepared using tap water and a secondary sedimentation tank water sample, respectively. The volume of tap water in each small-scale test water sample was recorded as V3. The preparation ratios and total phosphorus concentrations of the four small-scale test water samples are shown in Table 1 below. The error rate between the measured total phosphorus concentration of the prepared water samples and the theoretical value did not exceed 3%, which is within a reasonable detection error range.

[0035] Table 1

[0036] The lower the total phosphorus concentration in the water sample and the smaller the dosing coefficient, the smaller the calculated PFS dosage will be. To avoid the calculated PFS volume being less than the minimum pipette range, resulting in inaccurate addition of a small volume of PFS, the PFS reagent can be diluted during the experiment to increase the volume of PFS added.

[0037] 1. Small test water sample 1 The total water sample for the small-scale test sample 1 was 3500 ml, which was divided into 7 equal portions of 500 ml each. The corresponding numbers are small-scale test samples 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, and 1-7. The dosing coefficient, PFS dosing volume, and total phosphorus concentration of the supernatant after coagulation for each portion of the water sample are shown in Table 2 below.

[0038] Table 2

[0039] With the total phosphorus concentration in the effluent as the x-axis and the dosage coefficient as the y-axis, a fitted curve was obtained. See details below. Figure 1 The R-squared value (coefficient of determination) is 0.9996, i.e., y = -32.461x. 3 + 48.292x 2 - 25.712x + 6.2641.

[0040] 2. Small test water sample 2 The total water sample for test sample 2 was 3500 ml, which was divided into 7 equal portions of 500 ml each. The corresponding numbers are test sample 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, and 2-7. The dosing coefficient, PFS volume added, and total phosphorus concentration of the supernatant after coagulation for each portion are shown in Table 3 below.

[0041] Table 3

[0042] With the total phosphorus concentration in the effluent as the x-axis and the dosage coefficient as the y-axis, a fitted curve was obtained. See details below. Figure 2 The R-squared value (coefficient of determination) is 0.9995, i.e., y = -38.138x. 3 + 52.118x 2 - 25.75x + 6.0689.

[0043] 3. Small test water sample 3 The total volume of water sample for test sample 3 was 3500 ml, which was divided into 7 equal portions of 500 ml each. The corresponding numbers are test samples 3-1, 3-2, 3-3, 3-4, 3-5, 3-6, and 3-7. The dosing coefficient, PFS volume added, and total phosphorus concentration of the supernatant after coagulation for each portion are shown in Table 4 below.

[0044] Table 4

[0045] With the total phosphorus concentration in the effluent as the x-axis and the dosage coefficient as the y-axis, a fitted curve was obtained. See details below. Figure 3 The R-squared value (coefficient of determination) is 0.9963, i.e., y = -48.713x. 3 + 58.284x 2 - 25.962x + 5.8043.

[0046] 4. Small test water sample 4 The total volume of water sample 4 was 3500 ml, which was divided into 7 equal portions of 500 ml each. The corresponding numbers are water sample 4-1, 4-2, 4-3, 4-4, 4-5, 4-6, and 4-7. The dosing coefficient, PFS volume added, and total phosphorus concentration of the supernatant after coagulation for each water sample are shown in Table 5 below.

[0047] Table 5

[0048] With the total phosphorus concentration in the effluent as the x-axis and the dosage coefficient as the y-axis, a fitted curve was obtained. See details below. Figure 4 The R-squared value (coefficient of determination) is 0.9994, i.e., y = -110x. 3 + 102.61x 2 - 37.058x + 6.1193.

[0049] This invention establishes a logical relationship for phosphorus removal agent dosing based on the relationship formula of the curve. This logical relationship can also be input into control software (such as Siemens WinCC OA, Schneider Electric Wonderware SystemPlatform, GE Digital iFIX, and Supcon WebField JX-300XP) in the form of code to achieve automated calculation.

[0050] Example 2: Collecting Operational Data Data on the operation of the high-efficiency sedimentation tank from August 1, 2024 to August 31, 2024 were collected. The effluent flow rate from the wastewater treatment plant outlet and the total phosphorus concentration from the online total phosphorus monitor were used as the sources for the influent flow rate and effluent total phosphorus concentration of the high-efficiency sedimentation tank. An online total phosphorus monitor was installed at the inlet of the high-efficiency sedimentation tank to obtain total phosphorus concentration data, with a detection frequency of once every 2 hours. The PFS density was 1.45 g / ml, and the iron content was maintained at approximately 11%. The dosage was read and exported from the flow meter.

[0051] Collect data on the total phosphorus concentration in the influent and effluent of the high-efficiency sedimentation tank, the effluent flow rate, and the PFS (Potentially Differentially Sprayed Fluid) dosing flow rate every 2 hours. Multiply the influent total phosphorus concentration by the effluent flow rate to obtain the total phosphorus mass in the influent every 2 hours. Multiply the PFS dosage by the PFS density by 2 hours to obtain the PFS dosage mass every 2 hours, then multiply by the iron content in the PFS to obtain the iron dosage mass every 2 hours. Convert the iron dosage mass and the influent total phosphorus mass to moles, and divide the moles of iron and phosphorus to obtain the dosing coefficient. Based on the influent total phosphorus concentration, select the curve closest to that concentration, and calculate the effluent total phosphorus concentration using the corresponding formula. Compare the calculated effluent total phosphorus concentration with the actual effluent total phosphorus measured by the online monitoring instrument.

[0052] Example 3: Modified Dosing Curve and Relationship Formula Under the same dosing factor, multiple different values ​​of total phosphorus concentration were observed in the actual effluent. The 90th percentile of the total phosphorus concentration under the same dosing factor was taken as the corresponding total phosphorus concentration value (C1). Under the same dosing factor, this value (C1) was compared with the total phosphorus concentration (C2) calculated using the corresponding formula. If the absolute value of the difference between C1 and C2 divided by C2 is less than or equal to 20%, the dosing curve is not corrected; if it is greater than 20%, the dosing curve and the corresponding formula are corrected.

[0053] Statistical analysis shows that from August 1, 2024 to August 31, 2024, the total phosphorus concentration in the influent of the high-efficiency sedimentation tank ranged from 1.12 mg / L to 1.67 mg / L. The deviation between the actual effluent total phosphorus concentration and the result calculated according to the corresponding curve formula is less than or equal to 20%. Therefore, there is no need to revise the dosing curve and the formula.

[0054] Example 4: Re-production and Application According to the set formula, the total phosphorus reagent is automatically added to achieve precise dosing.

[0055] Example 5: Method for Correcting the Dosing Curve The following assumptions are used to simulate the correction method for the dosing curve. It is assumed that the total phosphorus concentration in the influent of the high-efficiency sedimentation tank is between 1.404 mg / L and 1.455 mg / L for a certain period of time, the dosing coefficient is 3, and the total phosphorus concentration in the effluent is shown in Table 6 below.

[0056] Table 6

[0057] The total phosphorus concentrations in the effluent from the table above are sorted, and the sorted total phosphorus concentrations in the effluent are shown in Table 7 below.

[0058] Table 7

[0059] Take the 90th percentile of the total phosphorus concentration in the effluent under the same dosage coefficient as the total phosphorus concentration value (C1) corresponding to that dosage coefficient. There are 12 sets of data. 12*90%=10.8, which is rounded to 11. Therefore, take the concentration ranked 11th as C1, that is, C1=0.136mg / L.

[0060] According to the formula "y = -38.138x" used in Example 1, the total phosphorus concentration of water sample 2 in the small-scale test was 1.5 mg / L. 3 +52.118x 2 -25.75x + 6.0689”, with the total phosphorus concentration in the effluent as the x-axis and the dosage coefficient as the y-axis. When the dosage coefficient is 3, the total phosphorus concentration in the effluent calculated using the single-variable solution method according to the relationship formula is 0.171 mg / L, i.e., C2 = 0.171 mg / L.

[0061] The deviation is calculated by dividing the absolute value of the difference between C1 and C2 by C2, i.e., ABS(0.136-0.171) / 0.171=20.47%. Since this deviation is greater than 20%, the dosing curve and the corresponding formula need to be corrected.

[0062] The value of "Total phosphorus concentration (mg / L) in the supernatant after coagulation" for "Small test samples 2-5" in Table 2 of Example 1, which was "0.17", was corrected to "0.136", while the rest of the table remained unchanged. The corrected curve's relationship formula is then y = -41.724x³ + 55.147x² - 26.067x + 5.9539, with an R-squared value (coefficient of determination) of 0.9792. The corrected curve is shown below. Figure 5 This relationship formula guides the precise application of phosphorus removal agents.

[0063] The above embodiments describe preferred embodiments of the present invention, but the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other way. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for precise dosing of phosphorus removal agents in a coagulation process unit of wastewater treatment, characterized in that, The coagulation process unit is a high-efficiency sedimentation tank, including the following steps: S1. Take the effluent from the secondary sedimentation tank and the influent from the biological treatment tank at the front end of the coagulation process unit in the sewage treatment process as samples. The effluent from the secondary sedimentation tank is not filtered, while the influent from the biological treatment tank is filtered. Measure the total phosphorus concentration of each sample. Add the filtered influent from the biological treatment tank to the effluent from the secondary sedimentation tank to prepare a water sample with a higher total phosphorus concentration. Add tap water to the effluent from the secondary sedimentation tank to prepare a water sample with a lower total phosphorus concentration. Finally, multiple sets of water samples with different total phosphorus concentrations and concentration gradients are formed. Each set of water samples is repeated multiple times. S2. Set multiple addition coefficients for each group of multiple water samples in S1. The addition coefficients are 1 to 4, and the gradient changes between adjacent addition coefficients. Calculate the amount of phosphorus removal agent to be added for each water sample based on the total phosphorus concentration of the water sample and the different addition coefficients. After adding the corresponding phosphorus removal agent and mixing, add the coagulant aid, let it stand after reaction, and detect the total phosphorus concentration of the supernatant. S3. Using the total phosphorus concentration in the supernatant of each water sample as the abscissa and the addition coefficient as the ordinate, curve fitting is performed to obtain the curve formula and corresponding coefficient of determination for each water sample. S4. Based on the total phosphorus concentration in the influent of the coagulation process unit to be added, select the curve in S3 that is closest to the total phosphorus concentration in the influent, set the target value of the total phosphorus concentration in the effluent of the coagulation process unit, and calculate the required dosage of phosphorus removal agent. S5. Based on the actual total phosphorus concentration C in the effluent of the coagulation process unit. 实际 The target total phosphorus concentration in the effluent, C 目标 Relationship, taking the same addition coefficient C 实际 The 90th percentile, corrected for the curve of dosing coefficient versus total phosphorus concentration in effluent, when C 实际 With C 目标 The absolute value of the difference divided by C 目标 If the result is less than or equal to 20%, the curve will not be corrected. This curve will be used as the final corrected relationship formula to guide the addition of phosphorus removal agents.

2. The method according to claim 1, characterized in that: The equipment involved in the wastewater treatment process includes coarse screens, influent pump station, fine screens, aerated grit chamber, intermediate sedimentation tank, AAO biological treatment tank, secondary sedimentation tank, high-efficiency sedimentation tank, denitrification filter, and disinfection tank; among which the high-efficiency sedimentation tank is a coagulation process unit.

3. The method according to claim 1, characterized in that: Based on the total phosphorus concentration range of the effluent from the secondary sedimentation tank over the past year, the required total phosphorus concentration range of the water samples should be adjusted. At the same time, the difference in total phosphorus concentration between the water samples at each gradient should be reduced as needed, and the number of water samples should be increased.

4. The method according to claim 1, characterized in that: The phosphorus removal agent is polyferric sulfate, and the coagulant is anionic PAM.

5. The method according to claim 1, characterized in that: When performing curve fitting in S3, set the trendline format and select the trendline option whose coefficient of determination is closest to 1, which will give you the curve and the corresponding relationship formula.

6. The method according to claim 1, characterized in that: The target value for total phosphorus concentration in the effluent of S4 is 30-50% of the upper limit of the standard.

7. The method according to claim 1, characterized in that: Before the correction in S5, the total phosphorus concentration, dosage, and flow rate data of the coagulation process unit influent and effluent were measured frequently over a period of time, and C was continuously tested under the same dosage coefficient. 实际 The 90th percentile was used to correct the curve of the dosing coefficient versus the total phosphorus concentration in the effluent.

8. The application of the method according to any one of claims 1 to 7 in the precise dosing of phosphorus removal agents in the coagulation process unit of urban wastewater treatment.

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