A pipe residual chlorine regulation system and method based on building and community secondary water age

Abstract

This invention relates to a pipeline residual chlorine control system and method based on the water age of secondary water supply systems in buildings and communities. It belongs to the field of water quality safety assurance and intelligent control technology for secondary water supply systems in buildings and communities. The invention includes a system for collecting user water volume and monitoring water age distribution in secondary water supply pipelines, and a system for predicting and controlling residual chlorine in secondary water supply pipelines. By collecting hourly water consumption data from user water meters, a hydraulic model and a residual chlorine decay model are constructed to calculate the hourly water age and hourly residual chlorine of each pipe section. Hourly water age control points and hourly residual chlorine control points are determined. The hourly residual chlorine control value is obtained by tracing back from the hourly residual chlorine control points along the reverse flow direction to the water tank outlet. Then, based on the risk of residual chlorine exceeding the standard at the two control points, a coupling correction is performed to obtain the hourly residual chlorine setpoint, which is used to control the amount of disinfectant added. This invention can effectively analyze the inherent water age and residual chlorine change patterns of secondary water supply pipeline systems, improving the accuracy and assurance level of residual chlorine control.

Description

Technical Field

[0001] This invention belongs to the field of secondary water supply water quality safety assurance and intelligent control technology, and in particular relates to a pipeline residual chlorine control system and method based on the water age of secondary water supply in buildings and communities. Background Technology

[0002] Secondary water supply systems in buildings and residential communities are a crucial component of urban water supply systems, and their water quality safety directly impacts the health and well-being of end-users. Currently, these systems commonly employ the method of adding disinfectants at the outlets of water tanks or pumps to maintain residual chlorine levels in the pipe network, inhibit microbial growth, and ensure water supply safety. However, the actual operation of secondary water supply systems is directly influenced by user water usage patterns—significant differences in water consumption at different times, in different buildings, and on different floors lead to marked spatiotemporal variations in the hydraulic residence time (i.e., water age) of different pipe sections. During periods of low water usage, water flow in the pipes is slow or even stagnant, significantly extending the water age, and residual chlorine may drop below the standard limit due to continuous decay. During peak water usage periods, water flow in some pipe sections is rapid, resulting in a shorter water age and limited residual chlorine decay. Furthermore, key parameters such as pipe diameter, pipe material, pipe age, and water temperature also significantly affect the residual chlorine decay rate, further exacerbating the complexity and unevenness of residual chlorine distribution in the pipe network.

[0003] Current secondary water supply residual chlorine control technologies typically employ a fixed dosing method, setting a relatively conservative, constant residual chlorine control value solely based on the residual chlorine readings at the water tank outlet or pump outlet to ensure that the residual chlorine at the end of the building's pipe network meets standards. This control method fails to consider the differences in hydraulic residence time within the secondary water supply pipeline system, lacks a dynamic hydraulic model based on actual user water usage patterns, and does not systematically analyze the residual chlorine decay patterns at different times and in different pipe sections. This leads to a dilemma in actual operation: on the one hand, if the set residual chlorine level is too low, there is a risk of insufficient or non-compliant residual chlorine at the end of the pipe network during periods of low water consumption and in pipe sections with longer water ages; on the other hand, if the set residual chlorine level is too high, it will result in excessively high residual chlorine levels during periods of high water consumption and in pipe sections with shorter water ages, affecting not only the taste and comfort of users but also potentially increasing the risk of disinfection byproduct formation.

[0004] Therefore, how to accurately identify the water age distribution characteristics and residual chlorine decay patterns of different time periods and pipe sections under the condition of dynamic changes in actual water consumption of users, and establish a dynamic control method for residual chlorine coupled with the spatiotemporal changes of water age in the pipeline system, is a key technical problem that urgently needs to be solved in the field of secondary water supply in buildings and communities. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a pipeline residual chlorine control system based on the water age of secondary water supply in buildings and residential communities, comprising: Water tanks, booster pumps, mixers, residual chlorine detectors for water tank outlets, secondary water supply pipeline systems for buildings and communities, user water meters, user water meter data acquisition systems, intelligent control systems, and automatic disinfectant dosing devices; The water tank, the booster pump, the mixer, the water tank outlet residual chlorine detector, and the building and community secondary water supply pipeline system are connected in sequence, and the disinfectant automatic dosing device is connected to the mixer; The user water meter data acquisition system, the booster pump, and the water tank outlet residual chlorine detector are respectively connected to the intelligent control system, and the intelligent control system is connected to the disinfectant automatic dosing device. The intelligent control system receives hourly water consumption data transmitted by the user's water meter data acquisition system and real-time residual chlorine monitoring values ​​detected by the water tank outlet residual chlorine detector. Based on the hourly water consumption data, it determines hourly water age control points and hourly residual chlorine control points. Based on the hydraulic model and residual chlorine decay model, it reverse-engineers the hourly residual chlorine control value at the water tank outlet from the hourly residual chlorine control points. Based on the preset residual chlorine standard value, it determines the residual chlorine exceedance risk of the hourly water age control points and the hourly residual chlorine control points. Based on the residual chlorine exceedance risk, it couples and corrects the hourly residual chlorine control value to obtain the hourly residual chlorine setpoint. Finally, it controls the dosage of the disinfectant automatic dosing device based on the hourly residual chlorine setpoint and the real-time residual chlorine monitoring value.

[0006] The present invention also proposes a method for controlling residual chlorine using the aforementioned system, comprising: Obtain hourly water consumption data from user water meters in the secondary water supply pipeline system of buildings and communities; Based on the hourly water consumption data and the structural parameters of the building and community secondary water supply pipeline system, a hydraulic model of the building and community secondary water supply pipeline system is constructed, and the hourly water age of each pipe section is calculated based on the hydraulic model to determine the hourly water age control point. Based on the hydraulic model and the preset residual chlorine decay model, the hourly residual chlorine of each pipe section is calculated to determine the hourly residual chlorine control point. Based on the preset residual chlorine standard value, determine the hourly residual chlorine control value of the hourly residual chlorine control point; Based on the hourly residual chlorine control value at the hourly residual chlorine control point, and based on the hydraulic model and the residual chlorine decay model, the hourly residual chlorine control value at the water tank outlet is obtained by backtracking from the hourly residual chlorine control point along the reverse flow direction, pipe segment by pipe. Based on the risk of residual chlorine exceeding the standard at the hourly water age control point and the hourly residual chlorine control point, the hourly residual chlorine control value is coupled and corrected to obtain the hourly residual chlorine set value at the water tank outlet. Based on the hourly residual chlorine setting value at the water tank outlet and the real-time residual chlorine monitoring value at the water tank outlet, the disinfectant automatic dosing device is controlled to add disinfectant to the mixer.

[0007] Optionally, hourly water consumption data from user water meters in the building and community secondary water supply pipeline system can be obtained, including: Collect the cumulative readings of the user's water meter; Convert the cumulative reading of the user's water meter into hourly water consumption; Based on the meter number of the user's water meter, the user's address, and the actual connection relationship between the inlet pipe, building riser, and household inlet pipe of the building and community secondary water supply pipeline system, determine the topological correspondence between the user's water meter and each pipe segment; Based on the topological correspondence, the hourly water consumption of each user's water meter is aggregated to the corresponding pipe segment to obtain the hourly water consumption of each pipe segment.

[0008] Optionally, a hydraulic model of the secondary water supply pipeline system of the building and community is constructed, including: Based on the structural form and device composition of the secondary water supply pipeline system of the building and community, the pipeline and pipe section information of the secondary water supply pipeline system of the building and community is determined, and the pipeline and pipe section information includes pipe diameter, pipe material and pipe age information; Based on the pipeline and pipe section data, construct a three-dimensional structural model of the building and community secondary water supply pipeline system; Based on the three-dimensional structural model, a hydraulic model is constructed under different flow velocity conditions.

[0009] Optionally, based on the hydraulic model and the preset residual chlorine decay model, the hourly residual chlorine of each pipe section is calculated, including: Based on the hydraulic conditions in the hydraulic model, and combined with the effects of pipe diameter, pipe material, pipe age, water temperature, and residual chlorine content on the residual chlorine decay rate of the secondary water supply pipeline system of the building and community, a residual chlorine decay model for each pipe section is constructed. The residual chlorine decay model is the EPANET-MSX multi-component water quality model, which couples a two-reactant phase decay model with an exponential biofilm wall decay model.

[0010] Optionally, the hourly residual chlorine control value of the hourly residual chlorine control point is determined according to a preset residual chlorine standard value, including: Based on the preset residual chlorine standard value, the compliance rate and risk of exceeding the standard of residual chlorine at the hourly residual chlorine control point are assessed. The risk of exceeding the standard includes the risk of low residual chlorine, the risk of moderate residual chlorine, and the risk of high residual chlorine. The hourly residual chlorine control value is determined based on the compliance rate and the results of the risk assessment of exceeding the standard.

[0011] Optionally, the hourly residual chlorine control value at the water tank outlet is obtained by tracing back from the hourly residual chlorine control point along the counter-current direction of the water flow, segment by segment, including: Determine the water age and residual chlorine variation patterns of each pipe section from the hourly residual chlorine control point along the counter-current direction to the water tank outlet; Based on the water age and residual chlorine variation patterns of each pipe section, starting from the hourly residual chlorine control value of the hourly residual chlorine control point, the hourly residual chlorine control value of the water tank outlet is obtained by working backwards along the counter-current direction for each pipe section.

[0012] Optionally, based on the risk of residual chlorine exceeding the standard at the hourly water age control point and the hourly residual chlorine control point, the hourly residual chlorine control value is coupled and corrected to obtain the hourly residual chlorine setpoint at the water tank outlet, including: Determine the risk of residual chlorine exceeding the standard at the hourly water age control point and the risk of residual chlorine exceeding the standard at the hourly residual chlorine control point; When the hourly water age control point or the hourly residual chlorine control point is at risk of substandard residual chlorine or low residual chlorine, a positive correction amount is taken. When neither the hourly water age control point nor the hourly residual chlorine control point has a risk of low residual chlorine, but at least one has a risk of high residual chlorine, a negative correction amount is taken. When both the hourly water age control point and the hourly residual chlorine control point are at a moderate risk of residual chlorine, the coupling correction amount is zero. The hourly residual chlorine control value is corrected based on the coupling correction amount to obtain the hourly residual chlorine setting value at the water tank outlet.

[0013] Optionally, based on the hourly residual chlorine setting value at the water tank outlet and the real-time residual chlorine monitoring value at the water tank outlet, the automatic disinfectant dosing device is controlled to add disinfectant to the mixer, including: Calculate the feedforward dosing flow rate based on the hourly residual chlorine setting value at the water tank outlet, the water supply flow rate, and the residual chlorine before dosing; The hourly residual chlorine setting value at the water tank outlet is compared with the real-time residual chlorine monitoring value at the water tank outlet to determine the residual chlorine deviation. The corrected dosing flow rate is obtained by performing proportional-integral feedback correction based on the residual chlorine deviation. The disinfectant automatic dosing device adds disinfectant to the mixer according to the modified dosing flow rate control. Specifically, when the adjusted added flow rate reaches the upper or lower limit of the flow rate, the accumulation of the integral term is stopped.

[0014] Optionally, when the hourly residual chlorine setting value at the outlet of the water tank reaches the preset upper limit and the hourly residual chlorine control point fails to reach the residual chlorine control target, the intelligent control system outputs a residual chlorine guarantee exceeding the limit prompt and triggers at least one of the following auxiliary guarantee measures: manual review, pipeline flushing, shortening the water tank residence time, or adjusting the water supply path.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: This invention, based on the actual water consumption and its variation patterns of end users in secondary water supply systems of buildings and communities, acquires hourly water consumption data through a user water meter data acquisition system and constructs hydraulic and residual chlorine decay models accordingly. It comprehensively analyzes the inherent dynamic changes and distribution patterns of water age and residual chlorine in the pipes and pipe sections of the secondary water supply pipeline system, effectively breaking the "black box" of unpredictable and unanalyzable residual chlorine variation patterns in secondary water supply pipeline systems. Based on the constructed three-dimensional structural model, hydraulic model, and residual chlorine decay model, it systematically quantifies the effects of key parameters such as pipe diameter, pipe material, pipe age, water temperature, and residual chlorine content on the residual chlorine decay rate, providing a theoretical basis and application feasibility support for the residual chlorine decay law. Furthermore, by constructing models of water age and residual chlorine changes in the pipeline system at different time periods... The dynamic distribution map identifies hourly water age control points and hourly residual chlorine control points, predicts and evaluates the residual chlorine protection and risk levels at various time periods, and establishes hourly residual chlorine control values ​​for water tank outlets. This provides a highly reliable, predictable, repeatable, and verifiable basis for the precise control of residual chlorine in water tank outlets. In addition, the constructed hydraulic model and residual chlorine decay model have self-learning capabilities. They can improve the water age change patterns based on annual, monthly, daily, and hourly data collected from water consumption data. This further filters and determines the key parameters of the dynamic distribution map of water age and residual chlorine change patterns, forming a closed-loop control mechanism of data acquisition—model prediction—residual chlorine control value back-calculation—online dosing—feedback correction, which can continuously improve the accuracy and reliability of the intelligent residual chlorine control system. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the system structure according to an embodiment of the present invention; In the diagram: 1. Water tank; 2. Booster pump; 3. Mixer; 4. Residual chlorine detector at the water tank outlet; 5. Secondary water supply pipeline system for buildings and communities; 6. User water meter; 7. User water meter data acquisition system; 8. Intelligent control system; 9. Automatic disinfectant dosing device.

[0017] Figure 2 This is a schematic diagram of the method flow according to an embodiment of the present invention; Figure 3 This is a time-by-time variation graph of water age control points under four operating conditions according to an embodiment of the present invention; Figure 4 The following is a comparison chart of the distribution of the number of water-using nodes in the pipeline during the characteristic period of average daily residual chlorine in an embodiment of the present invention. Among them, (a) is a chart with residual chlorine of 0.15 mg / L at the outlet of the water tank; (b) is a chart with residual chlorine of 0.4 mg / L at the outlet of the water tank; and (c) is a chart after reverse calculation. Figure 5 This is a comparison chart of the percentage of time periods with moderate residual chlorine at each water-using node in the pipeline section on average daily, according to an embodiment of the present invention. Figure 6 This is a graph showing the hourly reverse calculation results of the residual chlorine setting value at the water tank outlet for five typical operating conditions according to an embodiment of the present invention. Figure 7 This is an hourly curve of the average daily water supply flow rate and disinfectant dosage in an embodiment of the present invention. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0020] Example 1 like Figure 1 As shown, this embodiment provides a pipeline residual chlorine control system based on the water age of secondary water supply in buildings and communities, including: a water tank 1, a booster pump 2, a mixer 3, a water tank outlet residual chlorine detector 4, a secondary water supply pipeline system for buildings and communities 5, a user water meter 6, a user water meter data acquisition system 7, an intelligent control system 8, and an automatic disinfectant dosing device 9.

[0021] Water tank 1, booster pump 2, mixer 3, residual chlorine detector 4, and building and community secondary water supply pipeline system 5 are connected in sequence; The automatic disinfectant dosing device 9 is connected to the mixer 3; The user water meter data acquisition system 7 is connected to the user water meter 6 and the intelligent control system 8; The booster pump 2 and the residual chlorine detector 4 are respectively connected to the intelligent control system 8; The intelligent control system 8 is connected to the automatic disinfectant dosing device 9.

[0022] Water in tank 1 is pressurized by pump 2 and enters mixer 3. Disinfectant automatic dosing device 9 delivers disinfectant to mixer 3. After the disinfectant is mixed with water, it enters the secondary water supply pipeline system 5 of the building and community through residual chlorine detector 4 and is supplied to users through user water meter 6.

[0023] The specific process of this invention is as follows: First, a physical model, a hydraulic model, and a residual chlorine decay water quality model are established based on the structural data of the secondary water supply pipeline system 5 in the building and community. Then, based on the topological correspondence between the user water meters and the actual water supply riser sections, the hourly water consumption of each user water meter is summarized into the corresponding pipe section in the pipeline model. Next, the intelligent control system 8 calculates the flow rate, flow velocity, water age, and residual chlorine distribution of the secondary water supply pipeline system 5 in the building and community on an hourly basis to determine the residual chlorine control point for each time period. Subsequently, with the residual chlorine at the residual chlorine control point reaching the control target as a condition, the residual chlorine control value at the outlet of water tank 1 is reversed from the residual chlorine control point, and the hourly residual chlorine control value is coupled and corrected to determine the hourly residual chlorine setpoint at the outlet of the water tank. Finally, the intelligent control system 8 controls the automatic disinfectant dosing device 9 based on the comparison between the residual chlorine control value and the online residual chlorine monitoring value of the residual chlorine detector 4, so that the disinfectant is mixed by the mixer 3 and then enters the secondary water supply pipeline system 5 of the building community, and performs closed-loop correction of the dosage based on the online detection results.

[0024] like Figure 2 As shown, this embodiment also provides a method for controlling residual chlorine using the above system, including: Obtaining hourly water consumption data from user water meters in the secondary water supply pipeline system of buildings and communities specifically includes: collecting the cumulative readings of user water meters, converting the cumulative readings of user water meters into hourly water consumption, determining the topological correspondence between user water meters and each pipe segment based on the meter number of user water meters, user address, and the actual connection relationship of the inlet pipe, building riser, and household inlet pipe of the secondary water supply pipeline system of buildings and communities, and summarizing the hourly water consumption of each user water meter to the corresponding pipe segment based on the topological correspondence to obtain the hourly water consumption of each pipe segment; Based on hourly water consumption data and structural parameters of the secondary water supply pipeline system in buildings and communities, a hydraulic model of the secondary water supply pipeline system in buildings and communities is constructed. Specifically, this includes: determining the pipe and pipe segment data of the secondary water supply pipeline system in buildings and communities based on the structural form and device composition of the secondary water supply pipeline system in buildings and communities. The pipe and pipe segment data includes pipe diameter, pipe material and pipe age information. Based on the pipe and pipe segment data, a three-dimensional structural model of the secondary water supply pipeline system in buildings and communities is constructed. Based on the three-dimensional structural model, a hydraulic model is constructed under different flow velocity conditions. Based on the hydraulic model, the hourly water age of each pipe segment is calculated to determine the hourly water age control point. Based on the hydraulic model and the preset residual chlorine decay model, the hourly residual chlorine of each pipe section is calculated to determine the hourly residual chlorine control point. Specifically, based on the hydraulic conditions in the hydraulic model, combined with the effects of pipe diameter, pipe material, pipe age, water temperature and residual chlorine content on the residual chlorine decay rate of the secondary water supply pipeline system of buildings and communities, a residual chlorine decay model for each pipe section is constructed. The residual chlorine decay model is the EPANET-MSX multi-component water quality model, which adopts a two-reactant phase decay model coupled with an exponential biofilm pipe wall decay model. Based on the preset residual chlorine standard value, determine the hourly residual chlorine control value for the hourly residual chlorine control point. Specifically, this includes: assessing the compliance rate and risk of exceeding the standard for the residual chlorine at the hourly residual chlorine control point based on the preset residual chlorine standard value. The risk of exceeding the standard includes the risk of low residual chlorine, the risk of moderate residual chlorine, and the risk of high residual chlorine. Based on the results of the compliance rate and risk of exceeding the standard assessment, determine the hourly residual chlorine control value. Based on the hourly residual chlorine control value at the hourly residual chlorine control point, and using the hydraulic model and residual chlorine decay model, the hourly residual chlorine control value at the water tank outlet is obtained by backtracking from the hourly residual chlorine control point along the counter-current direction, pipe by pipe. Specifically, this includes: determining the water age and residual chlorine variation pattern of each pipe section from the hourly residual chlorine control point along the counter-current direction to the water tank outlet; and, based on the water age and residual chlorine variation pattern of each pipe section, backtracking from the hourly residual chlorine control value at the hourly residual chlorine control point along the counter-current direction, pipe by pipe, to obtain the hourly residual chlorine control value at the water tank outlet. Based on the risk of residual chlorine exceeding the standard at the hourly water age control point and the hourly residual chlorine control point, the hourly residual chlorine control value is coupled and corrected to obtain the hourly residual chlorine setpoint at the water tank outlet. Specifically, this includes: determining the risk of residual chlorine exceeding the standard at the hourly water age control point and the hourly residual chlorine control point; when either the hourly water age control point or the hourly residual chlorine control point is at risk of substandard or low residual chlorine, a positive correction amount is taken; when neither the hourly water age control point nor the hourly residual chlorine control point is at risk of low residual chlorine, but at least one is at risk of high residual chlorine, a negative correction amount is taken; when both the hourly water age control point and the hourly residual chlorine control point are at moderate residual chlorine risk, the coupled correction amount is zero; and the hourly residual chlorine control value is corrected based on the coupled correction amount to obtain the hourly residual chlorine setpoint at the water tank outlet. Based on the hourly residual chlorine setpoint at the water tank outlet and the real-time residual chlorine monitoring value at the water tank outlet, the automatic disinfectant dosing device is controlled to add disinfectant to the mixer. Specifically, this includes: calculating the feedforward dosing flow rate based on the hourly residual chlorine setpoint at the water tank outlet, the water supply flow rate, and the residual chlorine before dosing; comparing the hourly residual chlorine setpoint at the water tank outlet with the real-time residual chlorine monitoring value at the water tank outlet to determine the residual chlorine deviation; performing proportional-integral feedback correction based on the residual chlorine deviation to obtain the corrected dosing flow rate; and controlling the automatic disinfectant dosing device to add disinfectant to the mixer based on the corrected dosing flow rate. When the corrected dosing flow rate reaches the upper or lower limit of the flow rate, the accumulation of the integral term is stopped. When the hourly residual chlorine setting at the water tank outlet reaches the preset upper limit and the hourly residual chlorine control point fails to reach the residual chlorine control target, the intelligent control system outputs a residual chlorine guarantee exceeding the limit prompt and triggers at least one of the following auxiliary guarantee measures: manual review, pipeline flushing, shortening the water tank residence time, or adjusting the water supply path.

[0025] Specifically, the following steps are included: Step 1: Establish the physical model of the pipeline network. Collect as-built drawings, pipeline data, and equipment data of the building and community secondary water supply pipeline system 5. Determine the connection relationships of water tank 1, booster pump 2, community pipeline network, building inlet pipe, building riser, and household inlet pipe. Record the elevation and corresponding floor of each node, and record the start and end nodes, length, pipe diameter, pipe material, roughness, and pipe age of each pipe segment. Analyze the building number, floor number, and room number according to the meter number and user address of user water meter 6. Combine this with the actual connection relationships of the inlet pipe, building riser, and household inlet pipe to determine the actual water supply pipe segment corresponding to each user water meter. Assemble the user water meters to the pipe segments connected to the water supply risers, establishing a topological correspondence between user water meters and water-using nodes in the pipe segments. For multiple user water meters on the same floor and supplied by the same floor's branch pipe, map them to the same floor's water-using node; for user water meters whose actual water supply connection relationship cannot be determined, mark them as unmapped water meters. A three-dimensional structural model consistent with the actual system is established in the intelligent control system 8.

[0026] Step 2: Establish a hydraulic-water quality coupling model. Input the topology, node parameters, and pipe segment parameters obtained in Step 1 into the hydraulic simulation platform to calculate the flow rate, velocity, head loss of each pipe segment, and the pressure and head of each node. Use the EPANET-MSX multi-component residual chlorine decay model to construct a residual chlorine decay model for all pipes and segments, including the community-district pipe network and building risers. Calculate the effects of key parameters such as pipe diameter, pipe material, pipe age, water temperature, and residual chlorine content on the residual chlorine decay rate of the building and community secondary water supply pipeline system 5 under different flow velocity conditions, and construct a residual chlorine decay model for all pipes and segments, including the building and community pipe network and building risers.

[0027] Specifically, by inputting water usage at different nodes, the topology, node elevations, pipe segment parameters, tank boundaries, pump characteristics, and valve status obtained in step 1 are input into EPANET to run a hydraulic simulation, obtaining node pressure, pipe segment flow rate, and pipe segment velocity under different water usage levels. The residual chlorine decay model calculates the residual chlorine decay law based on water body phase reaction and pipe wall reaction. The hydraulic model uses the Hazen-Williams formula to calculate pipeline head loss, and the residual chlorine decay model uses the EPANET-MSX multi-parameter residual chlorine decay model, which couples a two-reactant phase decay model with an exponential biofilm pipe wall decay model to reflect the influence of fast reactants, slow reactants, pipe wall biofilm, and mass transfer processes on residual chlorine decay.

[0028] Set the free residual chlorine component in EPANET-MSX fast reactant components and slow reactant components The residual chlorine decay was described using the 2RA bulk reaction and the EXPBIO tube wall reaction.

[0029] The bulk reaction equation for 2RA is: , as well as ,in and These are the fast reaction rate constant and the slow reaction rate constant, respectively. This represents the residual chlorine loss per unit volume of water through the pipe wall. The EPANET-MSX solver explicitly updates this at each water quality time step. , and The updated concentration is then transported to downstream nodes along with the flow rate of the pipeline section, thereby reflecting the depletion of fast reactants, the continued reaction of slow reactants, and the impact of different water supply paths on residual chlorine decay.

[0030] The residual chlorine loss in the pipe wall was calculated using the EXPBIO model. Biofilm reaction intensity. ,in This represents the maximum reactivity of the biofilm. Residual chlorine inhibition coefficient; liquid film mass transfer coefficient ,in for number, The molecular diffusion coefficient is... The diameter of the pipe; considering the combined limitations of biofilm reaction and liquid film mass transfer, the wall reaction intensity. Pipe wall loss item ,in The pipe wall area per unit volume of water, for a circular pipe. Pick The model uses instantaneous local residual chlorine at each water quality time step. Calculate pipe wall losses using instantaneous hydraulic variables.

[0031] Step 3: Determine the water age of each pipeline based on residents' water usage behavior and the pipeline network model. The user water meter data acquisition system 7 collects the cumulative readings of user water meters 6. The intelligent control system 8 summarizes the hourly water consumption of user water meters mapped to the same pipeline segment and assigns the summarized hourly water consumption to the corresponding pipeline segment, forming the hourly water demand for each pipeline segment. The water age of the tap water entering the building and community secondary water supply pipeline system 5 is set to zero, and the water age of each pipeline segment is calculated according to the water flow and node mixing process. The 24-hour water demand pattern is repeatedly simulated for multiple cycles, and the water age result of the last cycle is extracted as the quasi-periodic stable result.

[0032] Specifically, let the cumulative readings of water meter 6 for the same building user be as follows: and The corresponding collection times are respectively and Then the water usage increment of this reading segment Duration During data processing, reading segments with negative increments, abnormal surges, water usage rates exceeding thresholds per unit time, and sampling intervals exceeding thresholds are removed. When a valid reading segment spans multiple hourly intervals, it is allocated according to the proportion of overlap between the reading segment and each hourly interval. User water meter 6 on the date... ,Hour Water consumption ,in For reading segments and hours The overlap duration, With m 3 Timing, The data is expressed in liters (L). Through the above processing, the irregularly collected cumulative readings are converted into meter-by-meter, hourly water consumption.

[0033] The hourly water consumption of all users' water meters 6 on the same floor is summed to obtain the hourly water demand for the floor, and then written into the corresponding node of the pipeline network model according to the user mapping relationship. Non-residential terminal water meters such as the main meter, commercial meters, and property management meters are removed. Nodes existing in the pipeline network model but without valid water meter mappings, as well as floor nodes with daily water consumption below the unoccupied threshold, are marked as unmapped nodes or unoccupied nodes. These nodes are not considered as candidate nodes for residual chlorine risk for normal users. This is based on the total number of residential water meters. and date Number of active water meters Calculate the normalization factor The hourly water consumption is then corrected using the normalization factor.

[0034] Step 4: Determine the water age distribution pattern and water age control points in the pipeline. The intelligent control system 8 generates a dynamic water age distribution map of the building and community secondary water supply pipeline system 5 in hourly order, statistically analyzes the average water age, minimum water age, and the time period of occurrence of the maximum water age at each water usage node in each pipe section, and identifies the pipe section with the longest water age in each time period. It also statistically analyzes the frequency, duration, and location changes of this maximum water age. The pipe section with the longest water age in each time period is then designated as the water age control point.

[0035] Step 5: Calculate the residual chlorine decay pattern and determine the residual chlorine control point. Use the time-of-use flow rate and water age obtained in Step 3 as the hydraulic boundary of the EPANET-MSX model, and input the measured residual chlorine from the effluent of water tank 1. Based on the EPANET-MSX calculation results, obtain the residual chlorine levels of each pipe section at different time periods. ,in For nodes In hours residual chlorine And a spatiotemporal dynamic distribution map of residual chlorine in the secondary water supply pipeline system of buildings and communities was formed. The residual chlorine level is below the acceptable threshold. Residual chlorine does not meet the threshold The residual chlorine level meets the standard and the threshold is moderate. The residual chlorine level is higher than the standard threshold. The residual chlorine levels at each water usage node in each pipeline section were statistically analyzed on an hourly basis, including periods of low chlorine levels, moderate chlorine levels, and periods of high chlorine levels. residual chlorine risk threshold Risk candidate node set This study demonstrates the risk correlation between water age and residual chlorine; it calculates the minimum residual chlorine value and the minimum residual chlorine pipe section for each time period, and extracts the residual chlorine value corresponding to the water age control point to determine whether the water age control point and the residual chlorine control point are consistent.

[0036] Step 6: Propose residual chlorine guarantee requirements and assess residual chlorine risks. Based on the residual chlorine standard value (0.05 mg / L) of relevant drinking water hygiene standards (GB5749-2022, CJ / T194-2005), evaluate the residual chlorine compliance rate and residual chlorine exceedance risk (low residual chlorine / moderate residual chlorine / high residual chlorine) for each pipe section at different time periods. Assess the proportion of the three risk situations of low residual chlorine, moderate residual chlorine, and high residual chlorine at water use nodes, establish hourly residual chlorine control values ​​for residual chlorine control points, and verify the residual chlorine control values ​​of hourly water age control points.

[0037] Step 7: Back-calculate the residual chlorine control value for the water tank outlet. Set multiple trial concentration points within the allowable residual chlorine range for water tank 1 outlet. For each trial concentration point, recalculate the residual chlorine decay process to obtain the residual chlorine response of the risk candidate node at each hour. Set the target residual chlorine control value. For nodes and hours The residual chlorine response curve was interpolated to obtain the result. achieve Minimum required residual chlorine concentration in water from tank 1 When the response curve exhibits local non-monotonicity, first treat the response curve for monotonicity, then refine the interval within the critical range using a trial-and-error method or a bisection method until the interval width is less than the back-calculation tolerance or the maximum number of iterations is reached. (hours) Residual chlorine control value at the outlet of the original water tank 1 Take the maximum residual chlorine concentration in the effluent from tank 1 required for all candidate risk nodes; the corresponding node is the hourly value. The residual chlorine control point.

[0038] Step 8: Adjust chlorination based on the coupling results of water age and residual chlorine. Perform coupling correction and engineering constraints on the residual chlorine control value at the outlet of water tank 1. Determine the residual chlorine correction amount at the water tank outlet based on the residual chlorine risk status of the two control points. A positive forced correction amount is applied when the residual chlorine at the control point fails to meet the standard. When the residual chlorine is low, a positive safety margin should be used. When the residual chlorine is moderate, the correction amount is 0; when the residual chlorine is too high, a negative correction amount is used. ,Right now: ; In the formula, j ∈ [water age control point, residual chlorine control point]. Specific values ​​can be calibrated based on the water quality model calculation results and actual pipe network measurement data. Correction amount for water age control points. and residual chlorine control point correction amount Coupling is implemented. When either control point is in a state of substandard or low residual chlorine, the low residual chlorine control requirement is prioritized, and the larger of the two positive correction values ​​is used. When neither control point has a risk of low residual chlorine and at least one control point has high residual chlorine, a negative correction value is used. When both control points are in a state of moderate residual chlorine, the correction value is 0. When one control point has low residual chlorine and the other has high residual chlorine, it indicates that using a single water tank outlet residual chlorine setpoint is insufficient to eliminate both types of risks simultaneously. In this case, the low residual chlorine control requirement is prioritized, and a risk conflict warning for the two control points is output. The basic residual chlorine control value is added to the coupled correction value to obtain the hourly residual chlorine setpoint at the water tank outlet. .

[0039] Set the lower limit of residual chlorine at the outlet of water tank 1. and upper limit First, Limited to and The amplitude limit is obtained between Then, the residual chlorine setpoint is obtained by first-order exponential smoothing. ,in (0< ≤1.0). The intelligent control system 8 uses the residual chlorine setpoint to re-predict the residual chlorine at the residual chlorine control point. If the maximum allowable setpoint still cannot make the residual chlorine control point reach the setpoint... When the residual chlorine level exceeds the limit, a warning message will be displayed, and manual verification, pipeline flushing, shortening the water tank residence time, or adjusting the water supply path will be initiated.

[0040] Let the water supply flow rate of booster pump 2 be... The residual chlorine at the outlet of water tank 1 before addition was... The effective chlorine concentration of the disinfectant is The mixed utilization coefficient is The residual chlorine replenishment pump of the automatic disinfectant dosing device 9 then adds flow rate. ,in The residual chlorine level is obtained through the residual chlorine detector 4 at the outlet of water tank 1. The automatic disinfectant dosing device 9 operates according to the residual chlorine replenishment pump flow rate. The disinfectant is mixed with water via mixer 3, and the residual chlorine detector 4 detects the actual residual chlorine after mixing. Intelligent control system 8 As feedback deviation The feedforward injection flow rate is corrected to obtain the corrected injection flow rate for the residual chlorine replenishment pump. , , This is for integral gain. When the corrected flow rate reaches the upper or lower limit of the pump flow rate, the integral term stops accumulating, i.e., anti-integral saturation treatment is adopted to prevent overshoot after the limit is lifted. The flow rate upper limit, maximum rate of change between adjacent control cycles, low flow interlock, no flow pump stop, and residual chlorine over-limit pump stop are set for the automatic disinfectant dosing device 9.

[0041] Step 9: Supplement data and iterate the model. The user water meter data acquisition system 7 continuously collects water volume data from user water meters 6. The intelligent control system 8 simultaneously saves data from the water tank 1 outlet flow meter, booster pump 2, and water tank 1 outlet residual chlorine detector 4, as well as instructions and anomaly records from the automatic disinfectant dosing device 9. The model compares the deviations between predicted and measured residual chlorine and predicted and measured flow rates according to a rolling time window. When data integrity conditions are met, the node water demand pattern is updated. , MSX parameters such as A and B.

[0042] The iterated model regenerates dynamic distribution maps of water age and residual chlorine based on year, month, day, and hour, and updates the longest water age point, residual chlorine control point, residual chlorine control point, and residual chlorine setpoint of the effluent from time-sharing water tank 1. If the updated parameters exceed the allowable range or the verification error increases, the original model parameters are retained and a manual verification prompt is issued to avoid control strategy drift caused by abnormal data.

[0043] Example 2 This embodiment uses a secondary water supply system in a residential community as an example. The community comprises 15 residential buildings, with water supply floors ranging from 1 to 18. Normally, variable frequency pumps are used for water supply, while during peak evening hours, a combination of an underground water tank and variable frequency pumps is used. The underground water tank has a volume of 250 m³. 3 The rated flow rate of the variable frequency pump is 30m³ / h. 3 The rated head is 128 m. The outdoor main pipe is mainly made of ductile iron, while the building risers use PPR pipes.

[0044] A community water supply network model was established using EPANET 2.2. The model includes 258 connection nodes, one constant-head water source, one water tank, 264 pipes, one water pump, and one flow control valve. Residential water usage was divided into 238 water usage nodes based on building and floor, covering 15 residential buildings. The model resolved the building, unit, and floor of each user's water meter based on the meter number and user address, and combined with the actual connection relationships of the building's inlet pipe, building riser, and floor branch pipes, mapping each user's water meter to the corresponding floor water usage node connected to the water supply riser. 231 water usage nodes were successfully mapped. The total pipeline length is approximately 1.924 km, including 26 DN150 pipes, 15 DN100 pipes, and 223 DN80 pipes. Nodes that were not mapped and floor nodes with daily water consumption below 10 L were not included in the normal user risk candidate set.

[0045] Water meters for building users are calculated based on a maximum cumulative reading increment of 3.0 m per segment. 3 Maximum water consumption rate per unit time: 1.0 m 3 Data was cleaned using the following parameters: hourly water consumption, maximum hourly water consumption per meter (500 L / h), and maximum sampling interval (48 h). Valid dates were then selected based on an hourly coverage rate of at least 0.80 and an active resident meter ratio of at least 0.50, resulting in 421 valid days. The average daily water consumption, maximum daily water consumption, summer high-temperature day, and low-water consumption day were all 425.16 m³ / h. 3 512.50 m 3 450.53 m 3 and 272.44 m 3 .

[0046] The hydraulic and water demand time steps were both set to 3600 s, and the water quality time step was set to 300 s. The 24-hour water demand model was simulated repeatedly for 3 days, and the results for the third day were extracted. EPANET-MSX model definition. , and Three parameters were used. The initial concentration of the fast reactant was 0.08 mg-Cl2 / L, and the initial concentration of the slow reactant was 0.50 mg-Cl2 / L. The fast reaction rate constant was 0.90 L / mg·h, and the slow reaction rate constant was 0.025 L / mg·h. The bulk temperature correction factor was 1.10, the reference temperature was 20 ℃, and the simulated water temperature was 25 ℃.

[0047] The maximum biofilm reactivity A in the EXPBIO tube wall model was taken as 0.40 m / h in MSX, the residual chlorine inhibition coefficient B was taken as 9.0 L / mg, and the molecular diffusion coefficient was taken as 1.30 × 10⁻⁶. -9 The flow rate is set to m² / s, the Schmidt number to 600, the minimum calculated flow rate to 0.03 m / s, the default pipe wall roughness to 0.10 mm, and the pipe age to 10 years. The water age risk threshold is set to 8 h, the residual chlorine risk threshold to 0.10 mg / L, the residual chlorine setpoint to 0.11 mg / L, and the residual chlorine setpoint threshold to 0.10–0.15 mg / L. The number of coarse grid points for the nonlinear response is set to 7, the back-calculation tolerance to 0.005 mg / L, and the maximum number of refinement iterations to 30.

[0048] The effective chlorine concentration of the disinfectant is taken as 50 g / L, and the mixing utilization coefficient of the mixer is taken as 0.9.

[0049] In this embodiment, J_SUPPLY in the pipeline network model is used as the control position for single-point dosing of residual chlorine in the main water supply pipe, and R_MUNI is used as the upstream water source node. The control value C of the residual chlorine control point is taken. target =0.05 mg / L, the limit for residual chlorine in drinking water is taken as 0.05 mg / L (GB5749-2022), and the lower limit of residual chlorine setting value for water tank outlet water C 0,min =0.10mg / L, upper limit C 0,max =2.00 mg / L, residual chlorine decay was calculated using the EPANET-MSX 2RA bulk reaction and EXPBIO tube wall reaction models. In this embodiment, δ0 = 0.15 mg / L, δ1 = 0.10 mg / L, and δ2 = -0.10 mg / L were taken.

[0050] Calculate the water age of each water-using node in each pipe section for each time period according to steps 3 and 4, and generate a dynamic water age distribution map. Extract the water-using node in the pipe section with the longest water age hourly as the water age control point. (See attached map) Figure 3As shown, the water age control points and their water ages under four operating conditions change significantly over time: the average daily water age control point ranges from 3.81 to 10.36 hours, mainly located at high-rise nodes such as B10_F13 and B03_F16; on the day with the highest water consumption and faster pipe transport, the water age control point migrates between multiple terminal nodes such as B03_F14, B11_F17, B13_F17, and B14_F15, with a water age ranging from 3.55 to 21.39 hours; on hot summer days, the water age ranges from 3.57 to 15.35 hours; on low water consumption days, due to lower water consumption and significantly longer pipe residence time, the water age control point stably appears at B14_F17 with a water age as high as 48.0 to 71.0 hours, significantly higher than other operating conditions, making it the most unfavorable operating condition for residual chlorine protection. The migration of water age control points between different operating conditions and time periods verifies the necessity of dynamically identifying water age control points.

[0051] Following step 5, input the time-sharing hydraulic results and the residual chlorine in the water tank outlet into the residual chlorine decay model. Calculate the residual chlorine at each node and categorize the periods according to residual chlorine value into periods of substandard residual chlorine (<0.05 mg / L), low residual chlorine (0.05–0.10 mg / L), moderate residual chlorine (0.10–0.30 mg / L), and high residual chlorine (>0.30 mg / L). Extract the node with the lowest residual chlorine value hourly as the residual chlorine control point. For example, consider the average daily value, as shown in the attached figure. Figure 4 As shown, when the residual chlorine at the water tank outlet is maintained at a constant 0.15 mg / L, the overall compliance rate is 99.6%, with 43.8% of the nodes having moderate residual chlorine and 55.8% having low residual chlorine. Another 0.4% of the nodes do not meet the standard. When the residual chlorine at the water tank outlet is maintained at 0.4 mg / L, the compliance rate is 100.0%, with 57.6% of the nodes having moderate residual chlorine and 42.4% having high residual chlorine. After reverse-engineering the time-sharing settings, the compliance rate reaches 100.0%, the proportion of nodes with moderate residual chlorine increases to 98.3%, and the proportion of nodes with high residual chlorine decreases to 0. The average daily residual chlorine control point is B08_F18 across 15 time periods, while the water age control point is B10_F13 across 20 time periods. The two types of control points do not overlap across 18 time periods, indicating that using only the longest water age point as the sole control basis is insufficient to guarantee residual chlorine at the distribution points.

[0052] Step 6 was used to evaluate the residual chlorine compliance rate, the percentage of nodes with moderate residual chlorine, and the percentage of nodes with excessive residual chlorine for each time period. The user node with the highest residual chlorine control value at the water tank outlet required to achieve the residual chlorine target was designated as the residual chlorine control point for that time period. The calculated residual chlorine control points for the four operating conditions were mainly B08_F18, B10_F13, B14_F16, and B08_F17, with a few periods shifting to higher-floor nodes such as B13_F17 and B08_F13. (See attached image) Figure 5As shown, when the residual chlorine at the water tank outlet is maintained at 0.15 mg / L, the compliance rates for the average day, the maximum day, the summer high-temperature day, and the low-water-use day are 99.6%, 99.6%, 99.7%, and 97.2%, respectively. The percentages of points with moderate residual chlorine are 43.8%, 49.2%, 45.3%, and 29.1%, respectively, and the percentages of points with high residual chlorine are 0 for all four operating conditions. When the residual chlorine at the water tank outlet is maintained at 0.4 mg / L, the compliance rate for all four operating conditions is 100.0%, with the percentages of points with moderate residual chlorine being 57.6%, 50.4%, 56.1%, and 75.6%, respectively, and the percentages of points with high residual chlorine reaching 42.4%, 49.6%, 43.9%, and 24.4%, respectively. After using the time-sharing setting values ​​obtained by reverse calculation using the present invention, the compliance rate of the four working conditions remained at 100.0%, the proportion of nodes with moderate residual chlorine increased to 98.3%, 98.4%, 98.5% and 97.1% respectively, and the proportion of nodes with excessive residual chlorine was controlled to 0.

[0053] Following step 7, set multiple trial concentration points within the allowable residual chlorine range of the water tank outlet. For each trial concentration point, recalculate the residual chlorine decay to obtain the residual chlorine response curve for the candidate risk nodes. Use interpolation to back-calculate and bring the residual chlorine control point to C. target The minimum required residual chlorine in the water tank outlet is determined, and the maximum value required by each candidate risk node is taken as the original control value for that period. Following step 8, based on the risk of residual chlorine exceeding the standard at the hourly water age control points and hourly residual chlorine control points in the pipeline system, the hourly residual chlorine control value is coupled and corrected, and then smoothed by upper and lower limits and a first-order exponential smoothing process to obtain the executable time-sharing setpoint. (See attached...) Figure 6 As shown, the residual chlorine setpoints at the water tank outlet dynamically varied within the range of 0.200–0.297 mg / L under four operating conditions: the average daily setpoint was 0.201–0.267 mg / L (average approximately 0.231 mg / L), the highest daily setpoint was 0.200–0.267 mg / L (average approximately 0.230 mg / L), the highest setpoint was 0.200–0.261 mg / L on hot summer days (average approximately 0.235 mg / L), and the highest setpoint was generally found on low water usage days, ranging from 0.232–0.297 mg / L (average approximately 0.259 mg / L). The setpoint curve showed an increase during periods of low water usage and unfavorable decay, and a decrease during periods of short water age, reflecting the characteristics of time-based, demand-driven control and avoiding insufficient or excessive residual chlorine under a fixed dosing method.

[0054] Step 8 involves calculating the disinfectant dosage based on the time-of-use setpoint and the actual measured water supply flow rate, and then using the online residual chlorine value from the water tank outlet residual chlorine detector for feedback correction. (See attached...) Figure 7As shown, the average daily water supply flow rate varies between 2.441 and 34.064 m³ / h, and the feedforward injection flow rate of the residual chlorine replenishment pump ranges from 0.013 to 0.172 L / h, with an average of approximately 0.090 L / h. The injection rate is lowest during the low flow period at night, and increases accordingly during the morning and evening peak water supply periods. The injection flow rate of the residual chlorine replenishment pump changes synchronously with the water supply flow rate and the target residual chlorine increase, indicating that this invention can achieve on-demand injection based on water usage patterns.

[0055] The table below shows the residual chlorine compliance rate, the percentage of nodes with moderate residual chlorine, the percentage of nodes with high residual chlorine, and the range of residual chlorine setting values ​​for the water tank outlet after reverse calculation, under four typical operating conditions with fixed residual chlorine levels of 0.15 mg / L and 0.4 mg / L in the water tank outlet, compared with the three methods of using the reverse-calculated time-sharing setting value of this invention. The proportions of the three items in the table are listed in the order of "outlet 0.15 / outlet 0.4 / after reverse calculation".

[0056] Explanation: The residual chlorine compliance rate is the percentage of the number of water usage periods with residual chlorine values ​​not lower than 0.05 mg / L out of the total number of water usage periods; the percentage of periods with moderate residual chlorine is the percentage of the number of water usage periods with residual chlorine values ​​between 0.10 mg / L and 0.30 mg / L out of the total number of water usage periods; the percentage of periods with high residual chlorine is the percentage of the number of water usage periods with residual chlorine values ​​greater than 0.30 mg / L out of the total number of water usage periods; the setpoint range for effluent residual chlorine is the range from the minimum to the maximum residual chlorine value at the outlet of the water tank after reverse calculation over 24 hours; the range of water age control points is the range from the minimum to the maximum water age at each water age control point within 24 hours.

[0057] It is evident that when the residual chlorine at the water tank outlet is fixed at 0.15 mg / L, the compliance rate for residual chlorine under the four operating conditions is 97.2%–99.7%, and the proportion of nodes with moderate residual chlorine is 29.1%–49.2%. The main problem is that the residual chlorine at the end of the pipe network is too low, and there are a few samples that do not meet the standard. When the residual chlorine at the water tank outlet is fixed at 0.4 mg / L, the compliance rate for residual chlorine under the four operating conditions is 100.0%, but the proportion of nodes with moderate residual chlorine is 50.4%–75.6%, and the proportion of nodes with high residual chlorine reaches 24.4%–49.6%. After using the present invention to back-calculate the residual chlorine control value of the water tank outlet based on the residual chlorine guarantee demand at the user end, the compliance rate for residual chlorine under the four operating conditions reaches 100.0%, the proportion of nodes with moderate residual chlorine increases to 97.1%–98.5%, and the proportion of nodes with high residual chlorine decreases to 0. This ensures that the residual chlorine at the end of the pipe network meets the standard while avoiding continuous high-concentration addition. Therefore, fixing the concentration at a low level can easily lead to insufficient residual chlorine at the terminal, while fixing the concentration at a high level will expand the range of excessive residual chlorine. Time-sharing reverse control can achieve a more stable balance between the two. The above embodiments verify the effectiveness of the time-sharing, on-demand, and closed-loop control of the present invention.

[0058] The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above-mentioned community size, number of nodes, and parameter values. For different building sizes, water supply zones, pipe combinations, water tank types, and data sampling cycles, the corresponding parameters can be adjusted while keeping the EPANET-MSX multi-parameter explicit transport, residual chlorine control point identification, concentration response grid back-calculation, and closed-loop chlorination process unchanged.

[0059] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A pipeline residual chlorine control system based on the water age of secondary water supply in buildings and communities, characterized in that, include: Water tank (1), booster pump (2), mixer (3), water tank outlet residual chlorine detector (4), building and community secondary water supply pipeline system (5), user water meter (6), user water meter data acquisition system (7), intelligent control system (8) and disinfectant automatic dosing device (9); The water tank (1), the booster pump (2), the mixer (3), the water tank outlet residual chlorine detector (4), and the building and community secondary water supply pipeline system (5) are connected in sequence, and the disinfectant automatic dosing device (9) is connected to the mixer (3); The user water meter data acquisition system (7), the booster pump (2) and the water tank outlet residual chlorine detector (4) are respectively connected to the intelligent control system (8) and the intelligent control system (8) is connected to the disinfectant automatic dosing device (9). The intelligent control system (8) is used to receive hourly water consumption data transmitted by the user water meter data acquisition system (7) and real-time residual chlorine monitoring value detected by the water tank outlet residual chlorine detector (4). Based on the hourly water consumption data, it determines the hourly water age control point and the hourly residual chlorine control point. Based on the hydraulic model and the residual chlorine decay model, it reverse-engineers the hourly residual chlorine control value of the water tank outlet from the hourly residual chlorine control point. Based on the preset residual chlorine standard value, it determines the residual chlorine exceedance risk of the hourly water age control point and the hourly residual chlorine control point. Based on the residual chlorine exceedance risk, it couples and corrects the hourly residual chlorine control value to obtain the hourly residual chlorine set value. Based on the hourly residual chlorine set value and the real-time residual chlorine monitoring value, it controls the dosage of the disinfectant automatic dosing device (9).

2. A method for controlling residual chlorine using the system described in claim 1, characterized in that, include: Obtain hourly water consumption data of user water meters (6) in the secondary water supply pipeline system (5) of buildings and communities; Based on the hourly water consumption data and the structural parameters of the building and community secondary water supply pipeline system (5), a hydraulic model of the building and community secondary water supply pipeline system (5) is constructed, and the hourly water age of each pipe section is calculated based on the hydraulic model to determine the hourly water age control point. Based on the hydraulic model and the preset residual chlorine decay model, the hourly residual chlorine of each pipe section is calculated to determine the hourly residual chlorine control point. Based on the preset residual chlorine standard value, determine the hourly residual chlorine control value of the hourly residual chlorine control point; Based on the hourly residual chlorine control value of the hourly residual chlorine control point, and based on the hydraulic model and the residual chlorine decay model, the hourly residual chlorine control value of the water tank (1) is obtained by back-tracing from the hourly residual chlorine control point along the reverse flow direction to the outlet of the water tank (1) segment by segment. Based on the risk of residual chlorine exceeding the standard at the hourly water age control point and the hourly residual chlorine control point, the hourly residual chlorine control value is coupled and corrected to obtain the hourly residual chlorine setting value at the outlet of the water tank (1). Based on the hourly residual chlorine setting value at the outlet of the water tank (1) and the real-time residual chlorine monitoring value at the outlet of the water tank (1), the disinfectant automatic dosing device (9) is controlled to add disinfectant to the mixer (3).

3. The method according to claim 2, characterized in that, Obtain hourly water consumption data from user water meters (6) of the building and community secondary water supply pipeline system (5), including: Collect the cumulative reading of the user's water meter (6); The cumulative reading of the user's water meter (6) is converted into hourly water consumption; Based on the meter number of the user water meter (6), the user address, and the actual connection relationship of the inlet pipe, building riser and household inlet pipe of the building and community secondary water supply pipeline system (5), determine the topological correspondence between the user water meter (6) and each pipe segment; Based on the topological correspondence, the hourly water consumption of each user water meter (6) is summarized to the corresponding pipe segment to obtain the hourly water consumption of each pipe segment.

4. The method according to claim 2, characterized in that, Constructing a hydraulic model of the secondary water supply pipeline system (5) of the building and community includes: Based on the structural form and device composition of the secondary water supply pipeline system (5) of the building and community, determine the pipeline and pipe section information of the secondary water supply pipeline system (5) of the building and community, including pipe diameter, pipe material and pipe age information; Based on the pipeline and pipe section data, construct a three-dimensional structural model of the building and community secondary water supply pipeline system (5); Based on the three-dimensional structural model, a hydraulic model is constructed under different flow velocity conditions.

5. The method according to claim 2, characterized in that, Based on the hydraulic model and the preset residual chlorine decay model, the hourly residual chlorine of each pipe section is calculated, including: Based on the hydraulic conditions in the hydraulic model, and combined with the effects of pipe diameter, pipe material, pipe age, water temperature and residual chlorine content on the residual chlorine decay rate of the secondary water supply pipeline system (5) of the building and community, a residual chlorine decay model for each pipe section is constructed. The residual chlorine decay model is the EPANET-MSX multi-component water quality model, which couples a two-reactant phase decay model with an exponential biofilm wall decay model.

6. The method according to claim 2, characterized in that, Based on the preset residual chlorine standard value, the hourly residual chlorine control value of the hourly residual chlorine control point is determined, including: Based on the preset residual chlorine standard value, the compliance rate and risk of exceeding the standard of residual chlorine at the hourly residual chlorine control point are assessed. The risk of exceeding the standard includes the risk of low residual chlorine, the risk of moderate residual chlorine, and the risk of high residual chlorine. The hourly residual chlorine control value is determined based on the compliance rate and the results of the risk assessment of exceeding the standard.

7. The method according to claim 2, characterized in that, The hourly residual chlorine control value is obtained by tracing back along the counter-current direction of the water flow from the hourly residual chlorine control point to the outlet of the water tank (1), including: Determine the water age and residual chlorine variation patterns of each pipe section from the hourly residual chlorine control point along the counter-current direction to the outlet of the water tank (1); Based on the water age and residual chlorine variation patterns of each pipe section, starting from the hourly residual chlorine control value of the hourly residual chlorine control point, the hourly residual chlorine control value of the water tank (1) outlet is obtained by reverse calculation along the counter-current direction for each pipe section.

8. The method according to claim 2, characterized in that, Based on the risk of residual chlorine exceeding the standard at the hourly water age control point and the hourly residual chlorine control point, the hourly residual chlorine control value is coupled and corrected to obtain the hourly residual chlorine setpoint at the outlet of the water tank (1), including: Determine the risk of residual chlorine exceeding the standard at the hourly water age control point and the risk of residual chlorine exceeding the standard at the hourly residual chlorine control point; When the hourly water age control point or the hourly residual chlorine control point is at risk of substandard residual chlorine or low residual chlorine, a positive correction amount is taken. When neither the hourly water age control point nor the hourly residual chlorine control point has a risk of low residual chlorine, but at least one has a risk of high residual chlorine, a negative correction amount is taken. When both the hourly water age control point and the hourly residual chlorine control point are at a moderate risk of residual chlorine, the coupling correction amount is zero. The hourly residual chlorine control value is corrected according to the coupling correction amount to obtain the hourly residual chlorine setting value of the water tank (1) outlet.

9. The method according to claim 2, characterized in that, Based on the hourly residual chlorine setting value at the outlet of the water tank (1) and the real-time residual chlorine monitoring value at the outlet of the water tank (1), the disinfectant automatic dosing device (9) is controlled to add disinfectant to the mixer (3), including: Calculate the feedforward dosing flow rate based on the hourly residual chlorine setting value at the outlet of the water tank (1), the water supply flow rate, and the residual chlorine before dosing; The hourly residual chlorine setting value at the outlet of the water tank (1) is compared with the real-time residual chlorine monitoring value at the outlet of the water tank (1) to determine the residual chlorine deviation; The corrected dosing flow rate is obtained by performing proportional-integral feedback correction based on the residual chlorine deviation. According to the modified dosing flow rate control, the disinfectant automatic dosing device (9) adds disinfectant to the mixer (3); Specifically, when the adjusted added flow rate reaches the upper or lower limit of the flow rate, the accumulation of the integral term is stopped.

10. The method according to claim 2, characterized in that, When the hourly residual chlorine setting value at the outlet of the water tank (1) reaches the preset upper limit and the hourly residual chlorine control point fails to reach the residual chlorine control target, the intelligent control system (8) outputs a residual chlorine guarantee exceeding the limit prompt and triggers at least one of the following auxiliary guarantee measures: manual review, pipeline flushing, shortening the water tank residence time, or adjusting the water supply path.

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