Water plant automatic chlorination process optimization method and device and storage medium

Abstract

The present application relates to the technical field of water treatment, and particularly relates to a water plant automatic chlorination process optimization method, device and storage medium. The method reads free chlorine content, monochloramine content and free ammonia content from clarified water flow data and filtered water flow data; automatically adjusts the amount of pre-chlorination according to pre-chlorination flow addition ratio, free chlorine target value and free chlorine content; calculates and automatically adjusts the current post-chlorination amount according to post-chlorination flow addition ratio, monochloramine target value and monochloramine content; calculates and automatically adjusts the current post-ammonia amount according to post-ammonia flow addition ratio, free ammonia target value and free ammonia content, until the free chlorine content, monochloramine content and monochloramine content all meet the requirements of the factory. Compared with the prior art, the present application has the advantages of automatically controlling the entire disinfection process chlorination and ammonia addition amount according to the monochloramine, free ammonia target value and dosing point water flow of the factory water, improving the disinfection quality of the factory water and the like.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to an optimization method, apparatus and storage medium for automatic chlorination process in water plants. Background Technology

[0002] With the implementation of the new "Standards for Drinking Water Quality" in my country, the number of routine disinfectant indicators in drinking water has increased from one (free chlorine) to four, adding monochloramine, ozone, and chlorine dioxide. Unconventional indicators such as ammonia nitrogen and trihalomethanes (a byproduct of chlorination) have also been added. Limits for some items are now stricter, requiring water supply companies to adjust and optimize their disinfection processes and chlorination methods.

[0003] In tap water disinfection, disinfection is usually carried out in the form of free chlorine or total chlorine (chloramine). Whether using online residual chlorine meters or in laboratories, total chlorine and free chlorine are easily analyzed, but monochloramine cannot be identified. In the new version of disinfectants, total chlorine is monochloramine, therefore, the chlorine / ammonia dosage ratio of 3.5-5:1 needs to be properly controlled. Currently, few water plants in China use free ammonia to adjust the chlorine / ammonia dosage ratio; that is, a small amount of free ammonia needs to be maintained in the water to ensure that the residual chlorine generated in the water is monochloramine. Free ammonia is NH3 / NH4 in water that can combine with chlorine. + .

[0004] When the chlorine-ammonia dosage ratio is greater than 5:1, the free ammonia level approaches zero, causing some monochloramine to convert into dichloramine, resulting in an unpleasant odor and taste in tap water. When excessive ammonia is added, the free ammonia level becomes too high (>0.2 mg / L), especially in summer when water temperatures exceed 15°C. Some of this free ammonia will convert into nitrite, increasing the nitrite concentration and thus lowering the monochloramine level. In severe cases, prolonged water retention in the pipe network (pump stations and reservoirs) can lead to low or near-zero residual chlorine levels, posing a potential risk to water supply safety.

[0005] In the current automatic chlorination and ammonia dosing process of the water plant, the automatic dosing control mode is as follows: the pre-chlorination / post-chlorination / ammonia dosing is based on the raw water influent flow rate, and the dosing ratio is manually set to automatically control the chlorination and ammonia dosing. The dosing ratio is manually adjusted according to changes in free chlorine in the sediment and total chlorine after filtration. However, the on-duty staff do not know how to correctly and reasonably adjust the dosing ratio based on changes in monochloramine and free ammonia. The automatic chlorination operation is as follows: pre-chlorination uses three sodium hypochlorite metering pumps (350L / h); post-chlorination uses three sodium hypochlorite metering pumps (150L / h); post-ammonia dosing uses three newly modified (20L / h) ammonium sulfate metering pumps; all operate with two in operation and one on standby. Pre-chlorination uses free chlorine (HClO) generated by breakpoint chlorination as the main disinfectant; post-filtration ammonia supplementation results in chlorine replenishment, and the effluent is disinfected with monochloramine (NH2Cl). In the aforementioned process flow, breakpoint chlorination can be automatically implemented based on the flow rate, dosage ratio, and free chlorine feedback. However, for chloramine disinfection, existing automatic chlorination systems present several problems: First, operators are unclear on how to rationally control the chloramine-ammonia dosage ratio according to the target residual chlorine level at the plant. Second, relying on total chlorine feedback without considering free ammonia limits lacks safety measures to prevent dichloramine contamination and ensure the biological stability of drinking water, resulting in low residual chlorine stability and safety, making automatic chlorination control difficult to apply in water treatment plants. These issues have long been a bottleneck hindering the development of automatic chlorination in China. Therefore, how to rationally control the chloramine-ammonia dosage ratio according to the target residual chlorine level at the plant, while considering free ammonia limits, and improving the accuracy, reliability, and safety of automatic chlorination control, has become a problem that needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art by providing an optimized method, device and storage medium for automatic chlorination process in water plants. This method uses a computer program to automatically control the free ammonia and monochloramine in the water leaving the water plant, and to finely control the amount of chlorine and ammonia added, so that the residual chlorine at the outlet is controllable and the water quality in the pipeline network is stable.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] According to a first aspect of the present invention, a method for optimizing an automatic chlorination process in a water plant is provided, comprising the following steps:

[0009] Obtain clarified water flow rate data and filtered water flow rate data; read the free chlorine content from the clarified water flow rate data; and read the monochloramine content and free ammonia content from the filtered water flow rate data.

[0010] Based on the pre-chlorination flow rate and dosage ratio, the target value of free chlorine, and the current free chlorine content, adjust the pre-chlorination amount and determine whether the free chlorine content is within the range of the target value. If yes, output the pre-chlorination amount; otherwise, readjust the pre-chlorination amount.

[0011] Based on the post-chlorination flow rate and dosage ratio, the target value of monochloramine at the factory outlet, and the current monochloramine content, calculate the current post-chlorination amount and determine whether the monochloramine content is within the range of the target value of monochloramine at the factory outlet. If yes, output the post-chlorination amount; otherwise, readjust the post-chlorination amount.

[0012] Based on the post-ammonia addition flow rate and ratio, the target value of free ammonia at the factory outlet, and the current free ammonia content, calculate the current post-ammonia addition amount, and determine whether the free ammonia content is within the range of the target value of free ammonia at the factory outlet. If yes, output the post-ammonia addition amount; otherwise, readjust the post-ammonia addition amount.

[0013] The pre-chlorination flow rate ratio, the post-chlorination flow rate ratio, the post-ammonia flow rate ratio, the free chlorine target value, the factory-exit monochloramine target value, and the factory-exit free ammonia target value are all preset.

[0014] As a preferred technical solution, before obtaining the clarified water flow rate data and the filtered water flow rate data, pre-chlorination, post-ammonia addition, and post-chlorination are performed according to the initial pre-chlorination amount, the initial post-ammonia addition amount, and the initial post-chlorination amount.

[0015] As a preferred technical solution, when the ammonia nitrogen in the clarified water is zero and the effluent is disinfected with chloramine, the initial amount of ammonia added is calculated based on the target value of the effluent monochloramine, and the initial amount of ammonia added is proportional to the target value of the effluent monochloramine.

[0016] As a preferred technical solution, the initial post-chlorination amount is calculated based on the difference between the target value of the monochloramine at the factory and the free chlorine content.

[0017] As a preferred technical solution, the amount of pre-chlorination is less than 2.3 mg / L.

[0018] As a preferred technical solution, the target value of free chlorine is in the range of 0.3-0.5 mg / L.

[0019] As a preferred technical solution, the target value of the monochloramine at the factory is in the range of 1.0-1.5 mg / L.

[0020] As a preferred technical solution, the target value of free ammonia at the factory outlet is in the range of 0.1-0.15 mg / L.

[0021] According to a second aspect of the present invention, an automatic chlorination process optimization device for a water plant is provided, comprising a memory, a processor, and a program stored in the memory, wherein the processor executes the program to implement the method described herein.

[0022] According to a third aspect of the present invention, a storage medium is provided having a program stored thereon, which, when executed, implements the method described thereon.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The automatic chlorination process optimization method for water plants provided by this invention can automatically control the amount of chlorine and ammonia added in the entire disinfection process according to the target values ​​of monochloramine and free ammonia in the effluent and the influent flow rate at the dosing point. It can help water plants to correctly master the new methods of chlorination and ammonia addition, improve the disinfection quality of effluent water, and ensure that the monochloramine and ammonia nitrogen assessment indicators of effluent water are better than the new national water quality requirements.

[0025] 2. This invention automatically adjusts the chlorination and ammonia dosage ratio based on feedback values ​​of free chlorine, monochloramine, and free ammonia, controlling the free ammonia in the treated water to a minimum limit (0.1-0.15 mg / L), reducing the amount of chlorine added, and stabilizing residual chlorine. This improves the taste of tap water.

[0026] 3. This invention optimizes the automatic chlorination process, highlighting its advanced technology and water quality safety. It makes automatic chlorination simple, practical, and effective, and has practical guiding significance for promoting and deepening automation in the domestic chlorination field. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a common automatic chlorination and ammonia addition process in a water plant.

[0028] Figure 2 This is a schematic diagram of the automatic chlorination / ammonia addition process in an embodiment of the present invention;

[0029] Figure 3 The values ​​represent the monthly average of chlorination / ammonia addition and monochloramine and free ammonia in the effluent from the embodiments of this invention. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0031] Example

[0032] like Figure 1 As shown, common automatic chlorination and ammonia dosing processes in water plants can be controlled automatically by a PLC control system through on-site data acquisition and signal feedback. Based on this, this embodiment provides an optimization method for the automatic chlorination process in water plants. The optimized automatic dosing control mode can automatically control the chlorination and ammonia dosage throughout the disinfection process according to the target values ​​of monochloramine and free ammonia in the effluent and the influent flow rate at the dosing point. It also automatically adjusts the chlorination and ammonia dosing ratio based on feedback values ​​of free chlorine, monochloramine, and free ammonia. Specifically, it includes the following steps:

[0033] (1) Set residual chlorine control target value

[0034] The level of residual chlorine target value will affect the amount of chlorination and ammonia added. Based on different water qualities, disinfection processes, and periodic algae changes, combined with the residence time of sedimentation water and clear water in the reservoir, the residual chlorine target values ​​for sedimentation water and effluent water should be scientifically and rationally set according to the CT value.

[0035] (2)Add chlorine before

[0036] The Qingcaosha Reservoir exhibits high water stability, low turbidity, and minimal ammonia nitrogen variation. Throughout the year, the maximum ammonia nitrogen concentration is 0.25 mg / L, with an average of 0.06 mg / L. Chlorination is primarily administered based on flow rate ratio, with the free chlorine concentration in the settled water controlled within the range of 0.3-0.5 mg / L. Furthermore, the free chlorine concentration is directly proportional to the dosage ratio, limiting the initial chlorination dose to <2.3 mg / L to reduce disinfection byproducts (trihalomethanes) generated during chlorination. The amount of chlorine added before chlorination is controlled by using the free chlorine concentration after sedimentation as feedback.

[0037] (3) Add ammonia afterwards

[0038] Because clarified water contains free chlorine and has zero ammonia nitrogen, ammonia needs to be added when the treated water is disinfected with chloramine. The amount of ammonia to be added is calculated based on the target value of residual chlorine in the treated water. To ensure that the treated water does not contain dichloramine or exceed the instrument detection limit, a free ammonia surplus of 0.1 mg / L must be considered. The amount of ammonia added is directly proportional to the target value of residual chlorine in the treated water (y = 0.2 × target value of monochloramine (1.3 mg / L) + 0.1). The target value for free ammonia in the treated water is set at 0.1-0.15 mg / L.

[0039] (4) Chlorine added later

[0040] The chlorination dosage is calculated based on the difference between the target value of residual chlorine (monochloramine) at the treatment plant and the free chlorine in the filter. The target value of monochloramine in the treated water is 1.3 mg / L (the new national standard is ≥0.5 mg / L), and the CT value is 86 (the national standard CT value is ≥60).

[0041] Control principle: First, determine whether the post-filtration feedback monochloramine is within the control range (1.0-1.5 mg / L), and then determine whether to adjust the amount of chlorine or ammonia based on the free ammonia value.

[0042] (5) Automatic control program

[0043] (5.1) Basic methods of program calculation

[0044] (5.1.1) Program calculation objective: To ensure that the residual chlorine in the process water is within the control setting range. Three control points are set: namely, the free chlorine detection point of the water after sedimentation, the detection point of monochloramine and free ammonia in the filtered water, and the detection point of residual chlorine and total ammonia in the effluent water.

[0045] (5.1.2) Calculation principle of the program: Set the target value of total chlorine in the effluent, and calculate the amount of chlorine and ammonia added to the process water in combination with the residual chlorine at each control point. Use monochloramine and free ammonia detection instruments to regulate the amount of chlorine and ammonia added after the process.

[0046] (5.1.3) Basic Calculation Formulas of the Program

[0047] Q_pre-chlorination L / h = [K1 + ΔC1] × Qm 3 / h influent / S (sodium hypochlorite available chlorine content 10% × density 1.16 × 1000);

[0048] Q after chlorination L / h = [K2 + ΔC2] × Qm 3 / h filtered effluent / S1(10%×1.16×1000);

[0049] Q after adding ammonia L / h = [K3 + ΔC3] × Qm 3 / h filtered effluent / S2 (ammonium sulfate effective ammonia content 9.71% × density 1.22 × 1000); indicates

[0050] Wherein, K1 represents the pre-chlorination flow rate and dosage ratio, in mg / L; △C1 represents the difference between the free chlorine in the settled water and the control target value, in mg / L; K2 represents the post-chlorination flow rate and dosage ratio, in mg / L; △C2 represents the difference between the total chlorine target value (monochloramine) at the effluent and the monochloramine in the filtered water, in mg / L; K3 represents the post-ammonia flow rate and dosage ratio; △C3 represents the difference between the free ammonia in the filtered water and the control target value at the effluent, in mg / L.

[0051] (5.2) Control Parameter Interface

[0052] This interface is only for water quality administrators to set and modify backend parameters; all parameters can be directly accessed by the control program.

[0053] Pre-chlorination interface: Set the pre-chlorination flow rate, dosage ratio K1, and free chlorine control target value.

[0054] Post-chlorination interface: Set the post-chlorination flow rate, dosage ratio K2, and the target value for the control of monochloramine at the factory outlet.

[0055] Post-ammonia addition interface: Set the post-ammonia addition flow rate, dosing ratio K3, and target value for free ammonia at the factory outlet.

[0056] (6) Process water monitoring instruments

[0057] (6.1) Online Free Ammonia Analyzer

[0058] The detection principle is similar to that of a portable instrument, but its operation is automatic. It can simultaneously display monochloramine and free ammonia, or display total ammonia nitrogen as the sum of the ammonia consumed by free ammonia and monochloramine (0.2 × monochloramine concentration). Residual chlorine meters measure total chlorine, and their values ​​tend to be higher than monochloramine concentrations; they cannot measure monochloramine. The online CA71A ammonia nitrogen meter measures total ammonia nitrogen but cannot measure free ammonia. Compared to online ammonia nitrogen meters, online free ammonia meters are cheaper and offer better value. Although daily operating reagent costs are relatively higher, this is especially important for automatic chlorination control.

[0059] (6.2) Portable Free Ammonia Analyzer

[0060] It can simultaneously detect monochloramine and free ammonia, and is simple to operate, accurate, and has a short measurement time (5-10 minutes) and low price. The on-duty staff manually inputs the measured data of free ammonia and monochloramine into the chlorination or ammonia addition process diagram interface, and the computer will directly and automatically control the amount of chlorination / ammonia added.

[0061] (7) The PLC in the chemical dosing room is equipped with control functions for post-chlorination and post-ammonia addition.

[0062] The system hardware will add an analog input module to the original chlorination PLC rack to read the post-chlorination and post-ammonia flow signals, realizing the monitoring function of chlorination and ammonia flow. Simultaneously, an analog output module will be added to adjust and control the stroke and frequency of the injection pump, achieving automatic control of post-chlorination and post-ammonia addition. The automatic chlorination / ammonia addition process is as follows: Figure 2 As shown. Q2 chlorine means chlorine is added after Q, and Q3 ammonia means ammonia is added after Q.

[0063] (8) Alarm and data analysis interface

[0064] (8.1) Alarm for malfunction of refueling equipment;

[0065] (8.2) Alarm for upper and lower limits of free chlorine, free ammonia, and monochloramine;

[0066] (8.3) Trend charts of influent flow rate, effluent flow rate after filtration, and chlorination / ammonia dosage, with hidden curves;

[0067] (8.4) Free chlorine in precipitated water, monochloramine and free ammonia in filtered water, and total chlorine trend chart at the factory outlet, etc. This analysis interface provides a basis for fault analysis, system evaluation, parameter adjustment, etc.

[0068] The above solution has been implemented in practice, and the optimization effects on production operations after implementation are as follows:

[0069] (1) Pre-chlorination (breakpoint chlorination)

[0070] The chlorination is automatically added based on the influent flow rate and chlorination ratio. The ammonia nitrogen in the raw water of Qingcaosha is low, the water quality is stable, the free chlorine in the sediment is basically within the control target range, and the residual chlorine is stable with small fluctuations. The initial chlorination dosage is 1.4-1.8 mg / L, and the free chlorine is 0.3-0.5 mg / L.

[0071] (ii) After filtration, chlorination and ammonia addition (chloramine disinfection) are performed.

[0072] The computer reads data on monochloramine and free ammonia measured online or manually using a portable instrument, and promptly implements intelligent program control to automatically adjust the chlorination and ammonia dosages, ensuring that the monochloramine and free ammonia levels in the treated water remain within the target range, as shown in Table 1. The subsequent chlorination concentration was 0.6-1.0 mg / L, and the ammonia dosage was reduced from 0.53 mg / L to 0.43 mg / L.

[0073] Table 1 Data of each control point under automatic control program

[0074]

[0075]

[0076] Note: + indicates increasing the dosage, - indicates decreasing the dosage.

[0077] When the free chlorine in the clarifier exceeds the set control range, the PLC control system will automatically reduce the pre-chlorination dosage according to the central target value. When the free chlorine is below the control range, it will automatically increase the pre-chlorination dosage. When the free ammonia or monochloramine in the filtration stage is high or low, the computer control system will make a judgment: first, determine whether the monochloramine is within the control range; then, determine whether the free ammonia is too high or too low; and finally, determine the chlorination dosage. When the monochloramine is too high and the free ammonia is too low, the post-chlorination dosage will be reduced; when the monochloramine is too low and the free ammonia is too high, the post-chlorination dosage will be increased.

[0078] (III) Data Analysis

[0079] System evaluation revealed that the initial chlorination consumption was relatively high. The overflow outlet (DN1000) in the open distribution well is approximately 8cm below the water surface; the higher the chlorination dosage, the greater the amount of free chlorine volatilized from the distribution well. Improvement measures:

[0080] 1. Install enclosed sunshades over the water distribution well;

[0081] 2. Reduce the impeller speed of the mechanically accelerated clarifier to lower the activated sludge return ratio to a reasonable return flow rate, thereby reducing the amount of free chlorine volatilization and chlorine consumption, thus reducing the amount of pre-chlorination and disinfection byproducts.

[0082] (iv) Parameter Adjustment

[0083] When diatoms appear in the raw water, the target value for free chlorine in the sedimented water can be adjusted to 0.8 mg / L and the chlorination flow rate and dosage ratio K2 after filtration can be reduced; when the raw water company pre-chlorinates (0.6-1.0 mg / L), the pre-chlorination flow rate and dosage ratio K1 can be reduced, etc.

[0084] (V) Comparison of Optimized Effects

[0085] 1) Before optimization: Automatic dosing control relied on manual setting of the chlorination and ammonia addition ratio. Sometimes, due to oversight, the chlorination / ammonia addition would be too high or too low, which could not be detected and adjusted in time, causing fluctuations in residual chlorine and the chlorination / ammonia addition. For example, monochloramine might be too low as 0.65 mg / L, and free ammonia might be too low as <0.05 mg / L or too high as 0.32 mg / L. Sometimes, there would also be differences in the residual chlorine levels of the two filtered waters (1# residual chlorine 0.8 mg / L, 2# residual chlorine 1.3 mg / L), affecting the stability of residual chlorine.

[0086] 2) After optimization: The automatic dosing control automatically controls the chlorination / ammonia dosing ratio throughout the entire process based on the target value of residual chlorine at the factory outlet. In particular, the feedback control of post-filtration monochloramine and free ammonia can automatically adjust the chlorination / ammonia dosing ratio at the injection point every 10-15 minutes (configurable), promptly detecting and adjusting to ensure the stability of residual chlorine and chlorination / ammonia dosage at the factory outlet, truly achieving dynamic and refined management of water quality. See Table 2 for details.

[0087] Table 2. Optimized operational data for chlorination disinfection in water plants (Unit: mg / L)

[0088]

[0089]

[0090] Note: Data before optimization is from May to September 2011; data after optimization is from January to May 2012. Total trihalomethane ratio ≤ 1 (new national standard).

[0091] 3) Optimized water quality leaving the plant

[0092] Monochloramine and free ammonia are more direct indicators of chlorination disinfection quality. After optimization, free ammonia is minimized, which eliminates the formation of dichloramine and reduces nitrification in the pipe network, thus lowering the risk of monochloramine formation. This maximizes the conversion of chlorine into monochloramine, reducing the amount of chlorine added and improving the taste of tap water – something that was difficult to achieve with the previous automatic dosing control. The monthly average levels of monochloramine and free ammonia in the chlorinated / ammoniated water are shown below. Figure 3 As shown (unit: mg / L).

[0093] In summary, the free chlorine disinfection and residence time in the sedimentation zone are sufficient to ensure the subsequent chloramine disinfection effect. It is recommended that the post-filtration chlorination (ammonia) dosing point be moved to the main effluent pipe before filtration and at the sedimentation tank (the post-filtration dosing point should be a backup). Its advantages are:

[0094] Firstly, it prolongs the filtration contact time of monochloramine disinfection, thereby increasing the CT value of the disinfectant factor;

[0095] Secondly, it avoids backwashing of the filter and volatilization of free chlorine on the surface of the tank, which would produce a chlorine smell and pollute the environment, and also reduces the consumption of free chlorine.

[0096] Third, the sampling time for monochloramine and the installation conditions for the electromagnetic flowmeter are better than those for the post-filtration dosing point;

[0097] Fourth, it avoids the direct addition of sodium hypochlorite and ammonium sulfate stock solutions to the tap water leaving the factory. Filtration helps ensure the safety of drinking water.

[0098] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. An optimization method for an automatic chlorination process in a water plant, characterized in that, Includes the following steps: The clarifier and filter are connected in sequence. A chlorination point is located before the clarifier, and a chlorination point and an ammonia addition point are located after the filter. Obtain clarified water flow rate data and filtered water flow rate data; read the free chlorine content from the clarified water flow rate data; and read the monochloramine content and free ammonia content from the filtered water flow rate data. Based on the pre-chlorination flow rate and dosage ratio, the target value of free chlorine, and the current free chlorine content, adjust the pre-chlorination amount and determine whether the free chlorine content is within the range of the target value. If yes, output the pre-chlorination amount; otherwise, readjust the pre-chlorination amount. Based on the post-chlorination flow rate and dosage ratio, the target value of monochloramine at the factory outlet, and the current monochloramine content, calculate the current post-chlorination amount and determine whether the monochloramine content is within the range of the target value of monochloramine at the factory outlet. If yes, output the post-chlorination amount; otherwise, readjust the post-chlorination amount. Based on the post-ammonia addition flow rate and ratio, the target value of free ammonia at the factory outlet, and the current free ammonia content, calculate the current post-ammonia addition amount, and determine whether the free ammonia content is within the range of the target value of free ammonia at the factory outlet. If yes, output the post-ammonia addition amount; otherwise, readjust the post-ammonia addition amount. The pre-chlorination flow rate ratio, the post-chlorination flow rate ratio, the post-ammonia flow rate ratio, the free chlorine target value, the factory-exit monochloramine target value, and the factory-exit free ammonia target value are all preset. The target value for free chlorine is 0.3-0.5 mg / L; the target value for monochloramine at the factory is 1.0-1.5 mg / L; and the target value for free ammonia at the factory is 0.1-0.15 mg / L.

2. The method for optimizing the automatic chlorination process in a water plant according to claim 1, characterized in that, Before obtaining the clarified water flow rate data and the filtered water flow rate data, pre-chlorination, post-ammonia addition, and post-chlorination are performed according to the initial pre-chlorination amount, initial post-ammonia addition amount, and initial post-chlorination amount, respectively.

3. The method for optimizing the automatic chlorination process in a water plant according to claim 2, characterized in that, When the ammonia nitrogen in the clarified water is zero and the effluent is disinfected with chloramine, the initial amount of ammonia added is calculated based on the target value of the effluent monochloramine, and the initial amount of ammonia added is proportional to the target value of the effluent monochloramine.

4. The method for optimizing the automatic chlorination process in water plants according to claim 2, characterized in that, The initial post-chlorination amount is calculated based on the difference between the target value of monochloramine at the factory and the free chlorine content.

5. The method for optimizing the automatic chlorination process in a water plant according to claim 1, characterized in that, The amount of pre-chlorinated material is less than 2.3 mg / L.

6. An automatic chlorination process optimization device for a water plant, comprising a memory, a processor, and a program stored in the memory, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1-5.

7. A storage medium having a program stored thereon, characterized in that, When the program is executed, it implements the method as described in any one of claims 1-5.

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