A method for evaluating water quality of pipe network

Abstract

This invention relates to a method for evaluating the water quality of a pipe network, including measuring the turbidity and total bacterial count at monitoring points in a water supply plant's pipe network during a monitoring period; calculating the average value and standard deviation of the turbidity and total bacterial count at each monitoring point during the monitoring period; calculating a water quality score for each monitoring point during the monitoring period according to a formula, with a higher score indicating better water quality; and judging the water quality at each monitoring point based on its calculated score. This invention incorporates indicators of water quality fluctuations to indicate the stability of pipe network segments, which can serve as a basis for judging the condition of pipe network segments. This method can objectively and accurately evaluate the condition of pipe segments and the impact of changes in water quality and quantity on the pipe network; it can also compare the water quality of different pipe network segments within a water plant's supply area to determine the condition of the pipe network within that area, thus providing scientific and robust support for water supply pipe network companies in managing their networks.

Description

Technical Field

[0001] This invention belongs to the field of safe pipeline transportation and distribution in drinking water treatment, and relates to a model and method for evaluating pipeline water quality, particularly a model and method for evaluating pipeline water quality between different pipeline monitoring points. Technical Background

[0002] With the improvement of social economy and people's living standards, people are paying more and more attention to the safety of drinking water quality. Drinking water quality safety not only requires that the water leaving the water treatment plant meet standards, but also that the quality of tap water needs to be monitored. This involves extending the safety of water quality leaving the water treatment plant to the safety of water quality during the drinking water transmission and distribution process, namely, the safety of water quality in the pipe network. Because the urban pipe network is a huge system, involving a wide area and complex conditions, such as differences in pipe materials, age, and diameter in different areas, even with the same water quality leaving the plant and the same supply volume, the impact of water quality and hydraulic factors on different pipe sections will vary. In particular, when the water quality and quantity in the pipe network change, some pipe sections may experience phenomena such as yellow or black water. Therefore, it is clear that the quality of water in the pipe network is closely related to the condition of each pipe section. Furthermore, changes in water source switching and water treatment process parameters at water supply plants can lead to variations in the quality of the treated water. Similarly, changes in water volume scheduling within the distribution network can alter the hydraulic conditions of pipe sections, resulting in changes in network water quality. Therefore, network water quality serves as a direct reflection of water plant process parameters, water source switching, and water volume control. However, network feedback is not instantaneous. Changes in network water quality typically exhibit a lag when water source switching or adjustments to water treatment processes and parameters occur. Moreover, due to differences in pipe materials and age across different pipe sections, the lag time is difficult to determine. Therefore, it is unwise to judge the impact of water quality and quantity changes on the network or the condition of individual pipe sections solely based on a single network water quality monitoring result. Thus, a scientific evaluation of network water quality is crucial for identifying poorly performing pipe sections and for water plants to optimize water treatment process parameters with network water quality as the primary objective.

[0003] Currently, the most widely used methods for evaluating water quality in pipe networks are fuzzy mathematics and comprehensive index methods. Fuzzy mathematics evaluation is based on single-point water quality data from each monitoring point, resulting in complex calculations and broad standards. However, due to the lag in feedback from the pipe network, it is difficult to objectively and scientifically present the true trend of water quality changes in a single evaluation. The comprehensive index method offers advantages such as intuitive results and high accuracy, but it also evaluates single-point water quality data from each monitoring point and suffers from the same technical limitations as fuzzy mathematics. More importantly, pipe network water quality fluctuates, and neither fuzzy mathematics nor comprehensive index methods can reflect these fluctuations.

[0004] With the continuous improvement of water treatment technology and the introduction of advanced treatment technology and third-generation membrane technology, the water quality of the pipeline network has been further improved on the basis of meeting the national drinking water hygiene standards. How to evaluate the water quality of the pipeline network based on its existing characteristics, i.e., the water quality indicators of the pipeline network are generally good, is an urgent problem to be solved. On the one hand, it provides a basis for pipeline network management companies to understand the status of the pipeline network system, and on the other hand, it points the way for water plants to optimize water plant processes and refine water plant process parameters. Summary of the Invention

[0005] The purpose of this invention is to address the feedback lag inherent in water supply networks due to differences in pipe material characteristics. This lag leads to inconsistent feedback times for the same changes in treated water quality across different pipe sections, resulting in biases in the scientific and effective evaluation of network water quality changes using single-point, single-time network water quality assessment methods. Furthermore, besides water quality indicators reflecting network water quality, the volatility of these indicators is also a crucial factor in network water quality evaluation. This invention incorporates indicators of water quality volatility to indicate the stability of pipe sections, serving as a basis for assessing their condition. This method can objectively and accurately evaluate the condition of pipe sections and the impact of water quality and quantity changes on the network. It also allows for comparison of water quality across different pipe sections within a water plant's supply area to determine the overall network condition within that region, thus providing strong scientific support for water supply network management by water supply companies.

[0006] To achieve the objectives of this invention, one aspect of this invention provides a method for evaluating the water quality of a pipe network, comprising the following steps:

[0007] 1) Among the water quality monitoring points in the water supply area of ​​the water supply plant, N monitoring points are randomly selected, and water samples are collected at each selected monitoring point during the monitoring period (the collected water samples are monitoring water samples), and the water quality of the water samples is measured at the same time.

[0008] 2) Calculate the average value and standard deviation of water turbidity and total bacterial count at each monitoring point in the pipeline network during the monitoring period. The average turbidity at each monitoring point during the monitoring period is recorded as the average turbidity value ZD. 点均值 The corresponding standard deviation is denoted as the standard deviation of turbidity at the monitoring point, ZD. 点偏差 The average number of colonies at each monitoring point during the monitoring period is recorded as the monitoring point colony mean JL. 点均值 The corresponding standard deviation is denoted as the standard deviation of colonies at the monitoring point JL. 点偏差 ;

[0009] 3) Calculate the water quality score for each monitoring point in the pipeline network during the monitoring period according to formula (3).

[0010]

[0011] In formula (3): score is the water quality score of each monitoring point in the regional pipe network; ZDi is the turbidity value of the water quality measured at each monitoring point in the regional pipe network during the monitoring period, NTU; JLi is the total number of colonies measured at each monitoring point in the regional pipe network during the monitoring period, CFU / mL; ZD 点均值 The average turbidity reading at each monitoring point within the regional pipeline network during the monitoring period is NTU; JL 点均值 ZD represents the average total bacterial count (CFU / mL) at each monitoring point within the regional pipe network during the monitoring period. 点偏差 The standard deviation of turbidity readings at each monitoring point within the regional pipeline network during the monitoring period; JL 点偏差 B1 is the standard deviation of the total bacterial count at each monitoring point within the regional pipe network during the monitoring period; B2 is the turbidity correction factor; B3 is the bacterial count correction factor; n is the total number of monitoring times at each monitoring point within the monitoring period, n = L × f, where L is the number of natural months corresponding to the monitoring period; f is the monitoring frequency; i is the order of the number of water quality measurements at each monitoring point within the monitoring period, with i ranging from 1 to n.

[0012] 4) Based on the water quality score calculated in step 3), determine the quality of the water at each monitoring point in the pipeline network; the higher the water quality score, the better the water quality at that monitoring point.

[0013] Based on the water quality scores measured at each pipeline monitoring point, and considering whether monitoring points with poor water quality (lower scores) are clustered together or whether the distance between monitoring points with poor water quality (lower scores) and the water plant shows a regular change (i.e., the score decreases as the distance to the water plant increases), this can provide a scientific basis for water plant and pipeline management, and provide scientific guidance for water plant process adjustments.

[0014] For example: if a monitoring point in a pipeline network has the highest water quality score, it indicates that this section of the pipeline is in the best condition. If the average water quality index of the section with the lowest score remains consistently high, it may indicate that the section is older or has thick and unstable scale buildup; replacement of this section is recommended to improve water quality. If the water quality index of this section fluctuates but the standard deviation is large, it indicates that this section of the pipeline is more sensitive and vulnerable. Water plants should pay close attention to the risk of water quality deterioration in this section when adjusting processes or parameters. Flushing this section can help ensure better water quality. It is worth noting that if monitoring points with lower scores are clustered together, it further suggests that the pipeline in that area may be older, and replacement is recommended. If the water quality score of a monitoring point changes regularly with the distance from the water plant, it may be necessary to monitor changes in residual chlorine along the pipeline; the water plant needs to conduct further analysis to take appropriate measures. In addition, if the water quality score at the same monitoring point in the pipeline network decreases significantly after the water source is switched or the process and parameters are adjusted, it indicates that the pipeline network is poorly adaptable to the new water source and the water source switching plan needs to be adjusted; or if the process or parameter adjustment is not conducive to improving the water quality of the pipeline network, the parameter needs to be adjusted in the opposite direction to achieve the purpose of fine management of process parameters.

[0015] In step 1), the number of water quality monitoring points selected is N≥5, and n is preferably 6-20, more preferably 8.

[0016] The pipeline monitoring points are evenly distributed within the monitoring area; the distance between two adjacent monitoring points is 1-2 kilometers.

[0017] In particular, the determination of water quality in step 1) refers to the determination of turbidity and colony count of the water sample.

[0018] In particular, the turbidity was determined by the scattering method in the "Standard Examination Methods for Drinking Water - Sensory Characteristics and Physical Indicators", and the turbidity unit was NTU; the total bacterial count was determined by the plate counting method in the "Standard Examination Methods for Drinking Water - Microbiological Indicators", and the bacterial count unit was CFU / mL.

[0019] In step 1), the monitoring period is ≥6 months, preferably 6-12 consecutive natural months, and more preferably 12 consecutive natural months.

[0020] In particular, in step 1), the water sample collection frequency (monitoring frequency) at each water quality monitoring point during the monitoring period is at least 2 times / month, preferably 2-4 times / month, and more preferably 2 times / month. That is, during the monitoring period, water samples are collected and water quality is measured at each water quality monitoring point at least 2 times per natural month, preferably 2-4 times.

[0021] In particular, the turbidity correction factor B1 mentioned in step 3) is determined according to the following method:

[0022] 3A) Calculate the average of all turbidity values ​​measured at all N selected pipeline monitoring points within the water quality assessment area during the monitoring period. That is, the average of all turbidity values ​​measured at all selected pipeline monitoring points during the monitoring period, denoted as the pipeline turbidity mean ZD. 管网均值 ;

[0023] 3B) Statistically analyze the turbidity data measured at each selected pipeline monitoring point within the monitoring period, noting that the turbidity value is lower than the average turbidity value ZD of the pipeline network. 管网均值 The number of times C;

[0024] 3C) Calculate the turbidity correction value B1 for each pipeline monitoring point according to formula (1).

[0025] B1=C / (L×f) (1)

[0026] In formula (1): B1 is the turbidity correction coefficient for each monitoring point; C is the turbidity value of each pipeline monitoring point that is lower than the average turbidity ZD of the pipeline network during the monitoring period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring period; f is the monitoring frequency, times / month;

[0027] The colony correction factor B2 mentioned in step 3) was determined as follows:

[0028] 3a) Calculate the average total number of bacterial colonies measured at all N selected pipeline monitoring points within the water quality assessment area during the monitoring period. That is, the average of all total bacterial colony data measured at all selected pipeline monitoring points during the monitoring period, denoted as the pipeline colony mean JL. 管网均值 ;

[0029] 3b) Statistically analyze the total bacterial count data of each selected pipeline monitoring point during the monitoring period, where the total bacterial count value is lower than the pipeline network average. 管网均值 The number of times D;

[0030] 3c) Calculate the colony correction value B2 for each pipeline monitoring point according to formula (2).

[0031] B2=D / (L×f) (2)

[0032] In formula (2): B2 is the colony correction coefficient for each monitoring point; D is the colony value at each pipeline monitoring point that is lower than the average colony value of the pipeline network during the monitoring period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring period; f is the monitoring frequency, times / month.

[0033] B1 is the turbidity correction factor, indicating that the turbidity value of each monitoring point in the pipeline network during the monitoring period is less than the average turbidity monitoring data of all monitoring points during the monitoring period (i.e., the average turbidity of the pipeline network).管网均值 B2 is the ratio of the number of times the turbidity value measured at a monitoring point is lower than the average turbidity value of the entire monitoring network (i.e., the average turbidity value of all monitoring points within the monitoring period) to the total number of monitoring times at that monitoring point within the monitoring period; B2 is the colony correction factor, which represents the ratio of the number of times the total number of colonies measured at each monitoring point within the monitoring period is lower than the average total number of colonies measured at all monitoring points within the monitoring period (i.e., the average colony value of the entire monitoring network). 管网均值 The ratio of the number of times the total number of colonies measured at a monitoring point is lower than the average number of colonies in the network to the total number of monitoring times at that monitoring point during the monitoring period; that is, the ratio of the number of times the total number of colonies measured at a monitoring point is lower than the average number of colonies in the network to the total number of monitoring times at that monitoring point during the monitoring period.

[0034] Another aspect of the present invention provides a method for evaluating the water quality of a pipe network, comprising the following steps:

[0035] 1) After the water source is switched, the treatment process or treatment parameters are adjusted at the water supply plant, N monitoring points are randomly selected from the water quality monitoring points in the water supply area to be evaluated, and water samples are collected at each selected monitoring point during the monitoring period (the collected water samples are the monitoring water samples), and the water quality of the water samples is measured at the same time.

[0036] 2) Review and retrieve water quality data from N monitoring points (the same as those in step 1) within the same water supply area of ​​the same pipeline network to be evaluated, before the water source switch, treatment process, or treatment parameter adjustment at the water supply plant, at the same monitoring frequency during the control period.

[0037] 3) Calculate the average value and standard deviation of water turbidity and total bacterial count at each monitoring point in the monitoring and control periods. The average turbidity at each monitoring point in the monitoring and control periods is recorded as the average turbidity value at the monitoring point, ZD. 点均值 The corresponding standard deviation is denoted as the standard deviation of turbidity at the monitoring point, ZD. 点偏差 The average number of colonies at each monitoring point during the monitoring and control periods is recorded as the average colony count at the monitoring point. 点均值 The corresponding standard deviation is denoted as the standard deviation of colonies at the monitoring point JL. 点偏差 ;

[0038] 4) Calculate the water quality score for each monitoring point in the pipeline network during the monitoring period and the control period according to formula (3A).

[0039]

[0040] In formula (3A): score is the water quality score of each monitoring point in the regional network during the monitoring period or control period; ZDi is the turbidity value of the water quality measured at each monitoring point in the regional network during the monitoring period and control period, in NTU; JLi is the total bacterial count measured at each monitoring point in the regional network during the monitoring period and control period, in CFU / mL; ZD 点均值 The mean of all turbidity values ​​measured at each monitoring point within the regional pipeline network during the monitoring period and the control period, NTU; JL 点均值 ZD represents the mean total bacterial count (CFU / mL) at each monitoring point within the regional pipe network during both the monitoring and control periods. 点偏差 The standard deviation of all turbidity test values ​​at each monitoring point within the regional pipeline network during the monitoring period and the control period, respectively; JL 点偏差 B represents the standard deviation of the total bacterial count values ​​at each monitoring point within the regional pipe network during the monitoring period and the control period, respectively. i B' is the turbidity correction coefficient; B2' is the colony correction coefficient; n is the total number of monitoring times at the pipeline monitoring points within the monitoring period or control period, n = L × f, where L is the number of natural months corresponding to the monitoring period or control period; f is the monitoring frequency; i is the order of the number of water quality measurements at the pipeline monitoring points within the monitoring period or control period, and the value of i is between 1 and n.

[0041] 5) Based on the water quality score calculated in step 4), determine the quality of the water at each monitoring point; the higher the water quality score, the better the water quality at that monitoring point.

[0042] Based on the water quality scores measured at each pipeline monitoring point, and considering whether monitoring points with poor water quality (lower scores) are clustered together or whether the distance between monitoring points with poor water quality (lower scores) and the water plant shows a regular change (i.e., the score decreases as the distance to the water plant increases), this can provide a scientific basis for water plant and pipeline management, and provide scientific guidance for water plant process adjustments.

[0043] For example: if a monitoring point in a pipeline network has the highest water quality score, it indicates that this section of the pipeline is in the best condition. If the average water quality index of the section with the lowest score remains consistently high, it may indicate that the section is older or has thick and unstable scale buildup; replacement of this section is recommended to improve water quality. If the water quality index of this section fluctuates but the standard deviation is large, it indicates that this section of the pipeline is more sensitive and vulnerable. Water plants should pay close attention to the risk of water quality deterioration in this section when adjusting processes or parameters. Flushing this section can help ensure better water quality. It is worth noting that if monitoring points with lower scores are clustered together, it further suggests that the pipeline in that area may be older, and replacement is recommended. If the water quality score of a monitoring point changes regularly with the distance from the water plant, it may be necessary to monitor changes in residual chlorine along the pipeline; the water plant needs to conduct further analysis to take appropriate measures. In addition, if the water quality score at the same monitoring point in the pipeline network decreases significantly after the water source is switched or the process and parameters are adjusted, it indicates that the pipeline network is poorly adaptable to the new water source and the water source switching plan needs to be adjusted; or if the process or parameter adjustment is not conducive to improving the water quality of the pipeline network, the parameter needs to be adjusted in the opposite direction to achieve the purpose of fine management of process parameters.

[0044] In step 1), the number of water quality monitoring points N ≥ 5, and n is preferably 6-20, and more preferably 8.

[0045] In particular, the determination of water quality in step 1) refers to the determination of turbidity and colony count of the water sample.

[0046] In particular, the turbidity was determined by the scattering method in the "Standard Examination Methods for Drinking Water - Sensory Characteristics and Physical Indicators", and the turbidity unit was NTU; the total bacterial count was determined by the plate counting method in the "Standard Examination Methods for Drinking Water - Microbiological Indicators", and the bacterial count unit was CFU / mL.

[0047] In step 1), the monitoring period is ≥6 months, preferably 6-12 consecutive natural months, and more preferably 12 consecutive natural months.

[0048] In particular, in step 1), the water sample collection frequency at each water quality monitoring point during the monitoring period is at least 2 times / month, preferably 2-4 times / month, and more preferably 2 times / month. That is, during the monitoring period, water samples are collected and water quality is measured at each water quality monitoring point at least 2 times per natural month, preferably 2-4 times.

[0049] In step 2), the control period is ≥6 months, preferably 6-12 consecutive natural months, and more preferably 12 consecutive natural months.

[0050] In particular, the control period is the period of network water quality monitoring before the water source switch, water plant treatment process or treatment parameter adjustment node, and is the same as the monitoring period duration.

[0051] In particular, the reference period should be at least 6 months before the water source switch, treatment process or treatment parameter adjustment time of the water supply plant, preferably 6-12 calendar months, and more preferably 12 calendar months.

[0052] The starting point for querying is the time node for water source switching, treatment process or treatment parameter adjustment, which is 6-12 months before the adjustment time node, preferably 12 months.

[0053] If the water source switch, treatment process, or treatment parameter adjustment time point is May 2015, then the control period is the 6-12 calendar months before May 2015, usually April and the months preceding April. For example, if the monitoring period is 6 months, then the control period is November and December 2014, and January, February, March, and April 2015. If the adjustment time point is August, then the control period is February, March, April, May, June, and July.

[0054] In particular, the water sample sampling frequency and water quality monitoring frequency were the same during the control period and monitoring period.

[0055] In particular, the months corresponding to the control period and the monitoring period can be the same or different.

[0056] In particular, the turbidity correction factor B1 mentioned in step 4) is determined according to the following method:

[0057] 4A) Calculate the average of all turbidity values ​​measured at all N selected pipeline monitoring points within the water quality assessment area during the monitoring and control periods. That is, the average of all turbidity values ​​measured at all selected pipeline monitoring points during the monitoring and control periods, denoted as the pipeline turbidity mean ZD′. 管网均值 ;

[0058] 4B) Statistically analyze the turbidity data measured at each selected pipeline monitoring point during the monitoring period and control period, and find those turbidity values ​​lower than the pipeline network average turbidity ZD′. 管网均值 The number of times C′;

[0059] 4C) Calculate the turbidity correction value B1′ for each pipeline monitoring point in the monitoring period and control period according to formula (1A).

[0060] B1′=C′ / (L×f) (1A)

[0061] In formula (1A): B1′ is the turbidity correction coefficient for each monitoring point; C′ is the turbidity value of each pipeline monitoring point that is lower than the average turbidity ZD′ of the pipeline network in the turbidity data measured during the monitoring period or control period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring cycle or control cycle; f is the monitoring frequency, times / month;

[0062] The colony correction factor B2′ mentioned in step 4) was determined as follows:

[0063] 4a) Calculate the average total number of bacterial colonies measured at all N selected pipeline monitoring points within the water quality assessment area during the monitoring and control periods. That is, the average total number of bacterial colonies measured at all selected pipeline monitoring points during the monitoring and control periods, denoted as the pipeline colony mean JL′. 管网均值 ;

[0064] 4b) Statistical analysis of the total bacterial count data at each selected pipeline monitoring point during the monitoring period and control period showed that the total bacterial count was lower than the pipeline network average value JL′. 管网均值 The number of times D′;

[0065] 4c) Calculate the colony correction value B2′ for each pipeline monitoring point in the monitoring period and control period according to formula (2A).

[0066] B2′=D′ / (L×f) (2A)

[0067] In formula (2A): B2′ is the colony correction coefficient for each monitoring point; D′ is the colony value at each pipeline monitoring point that is lower than the average colony value JL′ of the pipeline network in the total colony count data measured during the monitoring period and control period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring period or control period; f is the monitoring frequency, times / month.

[0068] B1′ is the turbidity correction factor, indicating that the turbidity value of each monitoring point in the pipeline network during the monitoring period and the control period is less than the average turbidity monitoring data of all monitoring points during the monitoring period and the control period (i.e., the average turbidity of the pipeline network, ZD′). 管网均值 The ratio of the number of times the turbidity value measured at a monitoring point is lower than the average turbidity value of the pipeline network (i.e., the average turbidity value of all monitoring points in the monitoring period and the control period) to the total number of times the monitoring point is monitored in the monitoring period and the control period.

[0069] B2′ is the colony correction factor, which indicates that the total number of colonies at each monitoring point in the water quality monitoring data within the monitoring period or control period is less than the average total number of colonies at all monitoring points within the monitoring period and control period (i.e., the average colony count of the pipe network, JL′). 管网均值 The ratio of the number of times the total number of colonies measured at a monitoring point is lower than the average number of colonies in the monitoring or control period to the total number of water quality monitoring at that monitoring point during the monitoring or control period; that is, the ratio of the number of times the total number of colonies measured at a monitoring point in the monitoring or control period is lower than the average number of colonies in the monitoring or control period to the total number of monitoring at that monitoring point during the monitoring or control period.

[0070] When using the method of this invention to evaluate and compare the water quality of different water supply areas within the same water supply plant, to ensure a more objective and accurate evaluation, it is advisable to set a long monitoring period under identical conditions. It is recommended that the monitoring period L be at least 6 months, with 12 months being optimal, and the monitoring frequency at least twice per month. It is important to note that monitoring points in different water supply networks being compared must maintain the same monitoring frequency and period. Before and after a water source switch or a change in water treatment process, the same monitoring point in the same water supply network must maintain the same monitoring frequency and period.

[0071] This invention calculates a score for each monitoring point independently and then compares the results. This method considers two key factors: first, it takes into account the time factor, avoiding reliance on a single water quality test to evaluate the pipe network, which could lead to bias; second, it considers fluctuations in pipe network water quality, as ideally, water quality should be stable, and significant fluctuations are undesirable. For example, if two sampling points have the same mean turbidity, but the first point shows only slight variations around the mean, while the second shows significant variations, then the second sampling point with larger variations will have lower water quality than the first stable sampling point. This invention can accurately evaluate and differentiate the difference in water quality between these two sampling points.

[0072] In the method of this invention, a higher score value at a pipeline monitoring point indicates better and more stable water quality at that monitoring point. When it is necessary to compare the impact of water source switching or water treatment process and parameter adjustment on pipeline water quality before and after the adjustment, the score value of the same pipeline monitoring point before and after the adjustment is measured. If the score after adjustment is higher than that before adjustment, it indicates that the pipeline water quality at that monitoring point is better after the water source switching or water treatment process and parameter adjustment; conversely, if the score after adjustment is lower than that before adjustment, it indicates that the pipeline water quality at that monitoring point has deteriorated after the water source switching or water treatment process and parameter adjustment.

[0073] Compared with existing pipe network water quality evaluation methods, the present invention has the following advantages:

[0074] 1. The method of the present invention comprehensively evaluates water quality indicators within the monitoring period. Since the water quality changes in the pipeline network are lagging behind the changes in the quality and quantity of water leaving the plant, it is difficult to accurately judge the impact of water quality and quantity changes on the pipeline network based on a single monitoring result. Therefore, compared with the existing methods that only use a single water quality monitoring result for evaluation, the method of the present invention is more objective and accurate.

[0075] 2. The method of this invention also considers the fluctuation of water quality in the pipe network. Assuming that within a certain period, two different pipe network monitoring points have the same average turbidity, with one monitoring point exhibiting slight fluctuations within the average range, while the other monitoring point shows both high and low turbidity values ​​(i.e., large turbidity fluctuations), existing evaluation methods, if using the average turbidity for evaluation, will result in identical water quality scores for the two monitoring points. Using a single data point for evaluation results in a random outcome that cannot represent the true situation. However, from a professional perspective, it is clear that monitoring points with smaller turbidity fluctuations have more stable water quality and should have higher scores. The method of this study can more intuitively present the differences caused by water quality fluctuations. Based on the magnitude of the water quality score difference over the monitoring period, the quality of water in each pipe section and monitoring point of the pipe network can be judged. This provides a basis for judging the effectiveness of water plant process parameter adjustments, process improvements, and water source switching. It also provides accurate information for optimizing water plant process parameters, refining management, and assessing process improvement status, ultimately achieving the goal of water plant process management based on pipe network water quality.

[0076] 3. The method of the present invention can establish a feedback relationship between changes in water quality in the pipeline network and changes in water source switching, water treatment process or parameters in water plants, which can provide a scientific and powerful basis for integrated management of water plants and networks and provide clearer objectives for adjusting water treatment processes and parameters in water plants. Detailed Implementation

[0077] The present invention will be further illustrated below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0078] Example 1

[0079] This embodiment takes the water quality monitoring data of a certain water supply plant during the monitoring period from January to December of a certain year as an example to evaluate the water quality of the pipeline network and judge the condition of the pipeline network.

[0080] 1. Set up pipeline monitoring points

[0081] In the regional pipe network to be evaluated, any 8 locations (i.e., the number of pipe network monitoring points N=8) are selected from the numerous water quality pipe network monitoring points set in advance by the water supply plant in the corresponding pipe section during the water supply process to monitor the pipe network water quality for the purpose of collecting pipe network water samples.

[0082] In this embodiment, the number of pipeline monitoring points selected in the water supply pipeline section to be evaluated is illustrated by taking N=8 as an example. Other numbers, such as N greater than 5, preferably 6-20, and preferably N=8, are also applicable to this invention.

[0083] 2. Water sample collection and water quality testing at monitoring points

[0084] Water samples were collected at each selected pipeline monitoring point, and the water quality of the collected water samples was measured, i.e., the water quality of the monitored water samples included turbidity (ZD) and total bacterial count (JL); among which, turbidity was measured by the scattering method in "Standard Examination Methods for Drinking Water - Sensory Characteristics and Physical Indicators", and the unit of turbidity was NTU; the total bacterial count was measured by the plate counting method in "Standard Examination Methods for Drinking Water - Microbiological Indicators", and the unit of bacterial count was CFU / mL.

[0085] The water sampling and water quality monitoring period (i.e., monitoring cycle, L) is usually at least 6 consecutive natural months, preferably 6-12 consecutive natural months, and more preferably 12 consecutive natural months; that is, L≥6 months;

[0086] The sampling frequency (or monitoring frequency f) at each monitoring point is at least 2 times / month (usually 2-4 times / month, preferably 2 times / month), that is, water samples are collected and water quality is measured at least 2 times per month at each monitoring point;

[0087] The sampling intervals are basically the same. For example, if f = 2 times / month, the sampling interval is 14-16 days, usually in the first and second ten days of each month. In this example, water samples are collected on the 1st and 16th of each natural month, and the turbidity and colony count of the water samples are measured.

[0088] The monitoring period in this embodiment is taken as January to December of a certain year. In this embodiment, the sampling monitoring period length L is 12 months, and for other durations L, it is at least 6 months, preferably 6-12 months, all of which are applicable to this invention. Taking water sample collection at a sampling frequency of 2 times / month at each monitoring point as an example, the water sample collection frequency at other monitoring points is usually 2-4 times / month, all of which are applicable to this invention. With a sampling period of 12 months for each monitoring point and a sampling frequency of 2 times / month for each monitoring point, a total of 24 water samples are collected at each water quality monitoring point within the monitoring period. The turbidity and total bacterial count of the 24 water samples are measured respectively, and the measured turbidity data is shown in Table 1, and the total bacterial count data is shown in Table 2.

[0089] 3. Measure the mean and standard deviation of water quality parameters at each monitoring point.

[0090] Based on the water quality parameter values ​​measured at each monitoring point, the mean and standard deviation of turbidity and total bacterial count at each monitoring point in the pipeline network were calculated within the monitoring period L (i.e., L = 12 months). The mean turbidity at each monitoring point within the monitoring period was denoted as the mean turbidity at the monitoring point (ZD). 点均值 The corresponding standard deviation is denoted as the standard deviation of turbidity at the monitoring point (i.e., ZD). 点偏差 The average number of colonies at each monitoring point during the monitoring period is recorded as the average colony count at the monitoring point (denoted as JL). 点均值 The corresponding standard deviation is denoted as the standard deviation of colonies at the monitoring point (i.e., JL). 点偏差 ).

[0091] In this embodiment, the average turbidity (i.e., ZD) of each monitoring point during the monitoring period is as follows: 点均值 ), mean colony count (JL) 点均值 ) and the corresponding standard deviation (ZD) 点偏差 JL 点偏差 As shown in Table 3. Among them, the lower the mean value of the water quality parameters, the better the water quality of the pipe network and the better the condition of the pipe network; the larger the standard deviation, the more unstable the condition of the pipe network.

[0092] 4. Calculate the turbidity correction value B1 for each monitoring point.

[0093] 4A. Calculate the average of all turbidity values ​​measured at all N pipeline monitoring points within the water quality assessment area during the monitoring period. That is, calculate the average of all turbidity data measured at all selected N pipeline monitoring points within the monitoring period (denoted as the pipeline turbidity mean ZD). 管网均值 );

[0094] The mean of turbidity data measured at all pipeline monitoring points within the monitoring period is the pipeline network turbidity mean, denoted as ZD. 管网均值 In this embodiment, for each pipeline monitoring point, measurements were taken twice per month over a 12-month period, resulting in 24 turbidity data points per monitoring point. For the eight monitoring points, a total of 8*24 turbidity data points were collected. The average value was taken and recorded as the pipeline network turbidity mean ZD. 管网均值 In this embodiment, ZD 管网均值 The value is 0.47 NTU, as shown in Table 1.

[0095] 4B. Statistically analyze the turbidity data measured at each pipeline monitoring point during the monitoring period, noting that the turbidity value is lower than the average turbidity value ZD of the pipeline network. 管网均值 The number of times (c) was recorded, and the statistical results are shown in Table 3.

[0096] 4C. Calculate the turbidity correction value B1 for each pipeline monitoring point according to formula (1).

[0097] B1=C / (L×f) (1)

[0098] In formula (1): B1 is the turbidity correction coefficient for each monitoring point; C is the turbidity value of each pipeline monitoring point that is lower than the average turbidity ZD of the pipeline network during the monitoring period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring period; in this embodiment, L = 12 months; f is the monitoring frequency, times / month; in this embodiment, f = 2.

[0099] Taking pipeline monitoring point N1 (the first monitoring point) as an example, the mean ZD of all pipeline monitoring turbidity data (i.e., 24 monitoring data from 8 pipeline monitoring points) is... 管网均值 The turbidity value was 0.47 NTU. Of the 24 measurements taken at monitoring point N1, 15 showed a turbidity value below 0.47 NTU. Therefore, the B1 value for monitoring point N1 is 15 / 24 = 0.63. Similarly, the B1 values ​​for monitoring points N2-8 were calculated, and the results are shown in Table 3.

[0100] 5. Calculate the colony correction value B2 for each monitoring point.

[0101] 5A. Calculate the average total number of bacterial colonies measured at all N pipe network monitoring points within the water quality assessment area during the monitoring period. This is the average of all total bacterial colony data measured at all selected N pipe network monitoring points during the monitoring period (denoted as the pipe network bacterial colony mean JL). 管网均值 );

[0102] The mean of the total number of bacterial colonies measured at all monitoring points in the pipeline network during the monitoring period is the pipeline network mean, denoted as JL. 管网均值 In this embodiment, for each pipeline monitoring point, measurements were taken twice per month over a 12-month period. Each monitoring point recorded a total of 24 colony counts, resulting in 8*24 colony counts for all 8 monitoring points. The average value was taken and recorded as the pipeline network colony mean JL. 管网均值 In this embodiment, JL 管网均值 The concentration was 2.38 CFU / mL, as shown in Table 2.

[0103] The average turbidity and average bacterial count of the pipe network are collectively referred to as the pipe network average.

[0104] 5B. Statistically analyze the total bacterial count data of each selected pipeline monitoring point during the monitoring period, noting that the total bacterial count is lower than the average bacterial count of the pipeline network. 管网均值 The number of occurrences (D) is shown in Table 3.

[0105] 5C. Calculate the colony correction value B2 for each pipeline monitoring point according to formula (2).

[0106] B2=D / (L×f) (2)

[0107] In formula (2): B2 is the colony correction coefficient for each monitoring point; D is the colony value at each pipeline monitoring point that is lower than the average colony value of the pipeline network during the monitoring period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring period; in this embodiment, L = 12 months; f is the monitoring frequency, times / month; in this embodiment, f = 2.

[0108] Taking monitoring point N1 in the pipeline network as an example, the average total bacterial count data of all pipeline network monitoring data (i.e., 24 monitoring data from 8 pipeline network monitoring points) was 1.21 CFU / mL. Twenty-two of the 24 monitoring data showed turbidity values ​​below 2.38 CFU / mL. Therefore, the B2 value of monitoring point N1 is 22 / 24 = 0.92. Similarly, the B2 values ​​of monitoring points N2-8 were calculated, and the results are shown in Table 3.

[0109] Table 1. Turbidity (NTu) data of water quality monitoring points in a certain area before water source switching.

[0110]

[0111] Table 2. Total bacterial count (cFu / mL) at water quality monitoring points in a certain area before water source switching.

[0112]

[0113] Turbidity correction factor B1 indicates that the turbidity value of the monitoring point in the regional pipeline network to be evaluated is less than the average turbidity ZD of the pipeline network during the monitoring period. 管网均值 The probability of a certain number of times the turbidity value is lower than the average turbidity value ZD of the pipe network among all the turbidity data measured at each pipe network monitoring point within the monitoring period. 管网均值 The ratio of the number of times the virus was detected to the total number of water quality monitoring tests within the monitoring period; the colony correction factor B2 indicates that the total number of colonies in the water quality monitoring data of the regional pipeline network monitoring points to be evaluated is less than the average colony count of the pipeline network. 管网均值 The probability of a given number of times occurring out of the total number of water quality monitoring sessions in the pipeline network refers to the percentage of times a given number of colonies occurs that is lower than the average colony count in the pipeline network among all the total colony count data measured at each monitoring point within the monitoring period. 管网均值 The ratio of the number of times the water quality was monitored to the total number of times the water quality was monitored within the monitoring period.

[0114] 6. Calculate the water quality score for each monitoring point.

[0115] Calculate the water quality score for each monitoring point in the pipeline network during the monitoring period according to formula (3).

[0116]

[0117] In formula (3): score is the water quality score of each monitoring point in the regional pipe network; ZDi is the turbidity value of the water quality measured at each monitoring point in the regional pipe network during the monitoring period, NTU; JLi is the total number of colonies measured at each monitoring point in the regional pipe network during the monitoring period, CFU / mL; ZD 点均值 The average turbidity reading at each monitoring point within the regional pipeline network during the monitoring period is NTU; JL 点均值 ZD represents the average total bacterial count (CFU / mL) at each monitoring point within the regional pipe network during the monitoring period. 点偏差 JL represents the standard deviation of all turbidity readings at each monitoring point within the regional pipeline network during the monitoring period. 点偏差 is the standard deviation of the total bacterial count at each monitoring point within the regional pipe network during the monitoring period; n is the total number of monitoring times at each monitoring point within the monitoring period, n = L × f, where L is the number of natural months corresponding to the monitoring period; f is the monitoring frequency; in this embodiment, L = 12, f = 2, n = 24; i is the order of the number of water quality measurements at each monitoring point within the monitoring period, with i values ​​ranging from 1 to n; B1 is the turbidity correction coefficient, indicating that the turbidity value of each monitoring point within the monitoring period is less than the average turbidity monitoring data of all monitoring points within the monitoring period (i.e., the average turbidity of the pipe network, ZD). 管网均值 B2 is the ratio of the number of times the turbidity value measured at a monitoring point is lower than the average turbidity value of the entire monitoring network (i.e., the average turbidity value of all monitoring points within the monitoring period) to the total number of monitoring times at that monitoring point within the monitoring period; B2 is the colony correction factor, which represents the ratio of the number of times the total number of colonies measured at each monitoring point within the monitoring period is lower than the average total number of colonies measured at all monitoring points within the monitoring period (i.e., the average colony value of the entire monitoring network). 管网均值 The ratio of the number of times the total number of colonies measured at a monitoring point is lower than the average number of colonies in the network to the total number of monitoring times at that monitoring point during the monitoring period; that is, the ratio of the number of times the total number of colonies measured at a monitoring point is lower than the average number of colonies in the network to the total number of monitoring times at that monitoring point during the monitoring period.

[0118] The water quality scores of monitoring points N1-8 in the pipeline network during the monitoring period are calculated according to formula (1), as shown in Table 3.

[0119] Table 3. Relevant data on turbidity and total bacterial count at water quality monitoring points in a certain area before water source switching, and water quality scores.

[0120]

[0121] Based on the water quality scoring results of the pipeline network, a higher score indicates better water quality at the monitoring point. Furthermore, a lower mean turbidity and smaller standard deviation at the monitoring point indicate a more stable pipeline network condition.

[0122] The calculation results show that in this embodiment, monitoring point N6 has the highest water quality score, with the smallest mean turbidity and standard deviation. Its mean and standard deviation of total bacterial count are also significantly lower than other monitoring points except for monitoring point 5. Although no total bacterial count was detected at monitoring point 5, which is lower than at monitoring point 6, the mean turbidity at monitoring point 5 is significantly higher and more volatile than at monitoring point 6. Therefore, this indicates that the water quality at monitoring point N6 is the best, and the pipeline network is stable. Monitoring points N4, N7, N3, and N8 have lower scores and larger standard deviations of total bacterial count, indicating that the water quality at these points is worse than at monitoring point N6.

[0123] Especially when switching water sources or adjusting water plant process parameters, pay attention to the total bacterial count at the aforementioned points. Additionally, based on the network water quality score and the location of each network monitoring point, observe whether monitoring points with poor water quality cluster or exhibit a regular change in distance from the water plant. This provides a scientific basis for water plant and network management. For example, if monitoring points with poor water quality cluster within a water plant's supply area, while other areas have better water quality, it indicates that the poor water quality in the clustered area may be due to network sensitivity, older pipes, unstable scale buildup, or other network-related issues, requiring replacement of the affected pipe section to resolve the problem. If the monitoring points with poor water quality exhibit a regular change in distance from the water plant (e.g., water quality worsens with distance), it may be due to reduced residual chlorine along the network, requiring the water plant to adjust process parameters to improve water quality.

[0124] Example 2

[0125] Due to water scarcity, a city or water plant may switch water sources due to water resource allocation. The water quality of different water sources may vary greatly. Since changes in water quality and quantity will have different impacts on the corrosiveness and impact on the pipeline network, how to evaluate the impact of water quality switching plans or water plant process adjustments on the pipeline network water quality is crucial to management decisions.

[0126] In this embodiment 2, the method of the present invention will be used to evaluate the water quality of the pipeline network before and after the water source switch. The method of the present invention can also be used to evaluate the water quality of the pipeline network before and after the water treatment process and treatment parameters of the water supply plant are adjusted.

[0127] This embodiment uses the same pipeline water quality monitoring area as in Embodiment 1 to evaluate the pipeline water quality and determine the pipeline condition after the water source switch. The pipeline water source switch is carried out immediately after the monitoring cycle in Embodiment 1 ends. That is, after the end of December 31 of a certain year, the new water source is replaced on January 1 of the following year, and water quality monitoring is carried out starting in January of the following year. The water quality monitoring time of the year before the water source switch (i.e., the monitoring cycle in Embodiment 1) is the control cycle in this Embodiment 2, and the water quality monitoring time of the year after the water source switch is the monitoring cycle of this Embodiment 2.

[0128] In this Example 2, the water quality data measured at a water supply plant in Example 1 from January to December of a certain year is used as the control period. The water quality data measured during this period are the water quality control data, denoted as the control group data. The monitoring period is one year after the water source change (i.e., one year after the end of monitoring in Example 1, i.e., January to December of the second year). The water quality data measured during this monitoring period are the water quality monitoring data, denoted as the monitoring group data. This is used to evaluate the water quality of the pipe network and assess the condition of the pipe network in a certain area after the water source switch.

[0129] 1. Set up pipeline monitoring points

[0130] Same as Example 1.

[0131] 2. Water sample collection and water quality testing at monitoring points

[0132] After the water source was changed, starting from January 1 of the following year after the end of December 31 of a certain year in Example 1, water samples were collected at each selected pipeline monitoring point, and the water quality of the collected water samples was measured, i.e., the water quality of the monitored water samples included turbidity (ZD) and total bacterial count (JL); wherein: turbidity was measured according to the scattering method in "Standard Examination Methods for Drinking Water - Sensory Characteristics and Physical Indicators", and the unit of turbidity was NTU; the total bacterial count was measured according to the plate counting method in "Standard Examination Methods for Drinking Water - Microbiological Indicators", and the unit of bacterial count was CFU / mL;

[0133] The water sampling and water quality monitoring period (i.e., monitoring cycle, L) is usually at least 6 consecutive natural months, preferably 6-12 consecutive natural months, and more preferably 12 consecutive natural months; that is, L≥6 months;

[0134] The sampling frequency (or monitoring frequency, f) at each monitoring point is at least 2 times / month (usually 2-4 times / month, preferably 2 times / month), that is, each monitoring point collects water samples and measures water quality at least 2 times per month;

[0135] The sampling intervals are basically the same. For example, if f = 2 times / month, the sampling interval is 14-16 days, usually in the first and second ten days of each month. In this example, water samples are collected on the 1st and 16th of each natural month, and the turbidity and colony count of the water samples are measured.

[0136] In this embodiment, the monitoring period is one year after the water source is changed (that is, one year after the end of the monitoring in Example 1, i.e., January to December of the second year). Within one year after the water quality monitoring time in Example 1, the water quality of the same pipeline monitoring points is measured at the same monitoring frequency. The water quality data measured within the monitoring period is the water quality monitoring data, which is recorded as the monitoring group data, i.e., the monitoring group. The monitoring results are shown in Tables 4 and 5.

[0137] 3. Review and retrieve water quality data from regional pipeline monitoring points within the control period to obtain water quality query data.

[0138] Before the water source switch or water treatment process or process parameter adjustment, the water quality (turbidity and total bacterial count) data of water samples collected from the same pipeline monitoring points within the same monitoring period and at the same monitoring frequency were reviewed and retrieved. The retrieved data was used as the control group data. In other words, the water quality data of water samples collected from the same pipeline monitoring points as the monitoring group within the control period were used as the control group data. The control period is the pipeline water sample collection and water quality monitoring period with the same duration as the monitoring period before the water source switch or water treatment process or process parameter adjustment of the water supply plant. The control period L is at least 6 consecutive natural months.

[0139] Before the water source switch, water treatment process, or process parameter adjustment, water quality (turbidity and total bacterial count) data of water samples collected within the same monitoring period, at the same monitoring points in the same pipeline network, and at the same monitoring frequency, are reviewed and retrieved. In other words, water samples collected by the water supply plant within the same water supply area before the water source switch, water treatment process, or treatment parameter adjustment, within the same monitoring period, at the same monitoring points in the same pipeline network, and at the same monitoring frequency, are used as control group water samples. The water quality data of the control group water samples is used as control group data, and the retrieved water quality data is called the query value. The retrieved turbidity data is called the turbidity query value; the retrieved bacterial count data is called the bacterial count query value.

[0140] The control period is the time period (calendar month) for collecting water samples from the pipeline network and monitoring water quality before the water source switch or the adjustment of water treatment processes or process parameters at the water supply plant, and it is the same length as the monitoring period. The calendar month of the control period and the monitoring period can be the same or different.

[0141] The control period begins with the month preceding the month of the water source switch or water treatment process / parameter adjustment at the water supply plant, and extends backwards for at least six consecutive calendar months. The control period is at least six consecutive calendar months prior to the water source switch or water treatment process / parameter adjustment, preferably six to twelve consecutive calendar months, and more preferably twelve consecutive calendar months. For example, if the monitoring period is six months, the control period is also six months. If the adjustment point is October of a certain year, the control period would be the six consecutive calendar months preceding October: April, May, June, July, August, and September. If the monitoring period is eight months, the control period would be the eight consecutive calendar months preceding October. If the monitoring period is twelve months, the control period would be one year earlier than the monitoring period, but the number of calendar months would be the same.

[0142] Table 4. Turbidity (NTU) data of water quality monitoring points in a certain area after water source switching.

[0143]

[0144] Table 5. Total bacterial count (CFU / mL) at water quality monitoring points in a certain area after water source switching.

[0145]

[0146] The control period begins with the month preceding the month of the water source switch or water treatment process / parameter adjustment at the water supply plant, and extends backwards for at least six consecutive calendar months. The control period is at least six consecutive calendar months prior to the water source switch or water treatment process / parameter adjustment, preferably six to twelve consecutive calendar months, and more preferably twelve consecutive calendar months. For example, if the monitoring period is six months, the control period is also six months. If the adjustment point is October of a certain year, the control period would be the six consecutive calendar months preceding October: April, May, June, July, August, and September. If the monitoring period is eight months, the control period would be the eight consecutive calendar months preceding October. If the monitoring period is twelve months, the control period would be one year earlier than the monitoring period, but the number of calendar months would be the same.

[0147] The monitoring period is the time span for water sample collection and water quality measurement (i.e., the length of a calendar month). The control period is the length of a calendar month for monitoring and control; the length of the control period is the same as the length of the monitoring period.

[0148] The control period and monitoring period are usually 6-12 months before and after the water supply plant switches its water source or adjusts its water treatment process or process parameters, preferably 12 months. That is, the control period is usually at least 6 months before the water supply plant switches its water source or adjusts its water treatment process or process parameters, preferably 6-12 months; the monitoring period is usually at least 6 months after the water supply plant switches its water source or adjusts its water treatment process or process parameters, preferably 6-12 months.

[0149] For example: The water supply plant adjusted its water treatment process and parameters in early October 2019. The monitoring period (monitoring calendar months) was October, November, and December 2019, and January to March 2020, a total of 6 consecutive calendar months. The monitoring period L was 6 months long. The monitoring period was the same as the control period. The control period was April, May, June, July, August, and September 2019, a total of 6 calendar months, or it could be February, March, April, May, June, and July 2019, a total of 6 calendar months. Other cases followed the same pattern.

[0150] This embodiment uses the water quality data measured at a water supply plant in Example 1 from January to December of a certain year as the control period. The water quality data measured within this control period are used as the water quality control data, referred to as the control group. The turbidity and colony count data of the control group water samples are shown in Tables 1 and 2, respectively. The monitoring period in this embodiment is taken as January to December of the second year following December of the year in Example 1. January to December of the year in Example 1 serves as the control period for this Example 2.

[0151] In this embodiment, the sampling and monitoring period L is taken as 12 months. For other durations, L is at least 6 months, and all are applicable to this invention. Taking water sample collection at a sampling frequency of 2 times / month at each monitoring point as an example, the water sample collection frequency at other monitoring points is usually 2-4 times / month, and all are applicable to this invention. The monitoring period and the control period are the same in length, and the corresponding natural months can be the same or different. In this embodiment, the natural months for water quality monitoring are the same.

[0152] 4. Measure the mean and standard deviation of water quality parameters at each monitoring point during the monitoring period and control period.

[0153] Based on the water quality parameter values ​​measured at each monitoring point, the mean and standard deviation of turbidity and total bacterial count at each monitoring point in the pipeline network were calculated during the monitoring period L (i.e., L = 12 months) and the control period. The mean turbidity at each monitoring point during the monitoring period and the control period was recorded as the mean turbidity at the monitoring point (denoted as ZD). 点均值 The corresponding standard deviation is denoted as the standard deviation of turbidity at the monitoring point (i.e., ZD). 点偏差 The average number of colonies at each monitoring point during the monitoring period and the control period is recorded as the average colony count at the monitoring point (denoted as JL).点均值 The corresponding standard deviation is denoted as the standard deviation of colonies at the monitoring point (i.e., JL). 点偏差 ).

[0154] In this embodiment, the water quality monitoring period L at the pipeline monitoring point is 12 months, and the control period is also 12 months, which is used as an example for illustration. Other monitoring periods, such as L being at least 6 months, are also applicable to this invention, preferably 6-12 months. The average turbidity, colony count, and corresponding standard deviation of each monitoring point in the monitoring period and control period are shown in Table 6.

[0155] The lower the average value of water quality parameters, the better the water quality of the pipe network and the better the condition of the pipe network; the larger the standard deviation, the more unstable the condition of the pipe network.

[0156] 5. Calculate the turbidity correction value B1′ for each monitoring point within the monitoring period and the control period.

[0157] 5A. Calculate the average of all turbidity values ​​measured at all selected pipeline monitoring points within the water quality assessment area during the monitoring and control periods. This is the average of all turbidity data measured at all selected pipeline monitoring points during the monitoring and control periods (denoted as the pipeline turbidity mean ZD′). 管网均值 );

[0158] The mean of all turbidity data measured at all pipeline monitoring points within the monitoring and control periods is the pipeline network turbidity mean, denoted as ZD′. 管网均值 In this embodiment, each pipeline monitoring point is measured twice per month within a 12-month monitoring period, resulting in a total of 24 turbidity data points per monitoring point; within a 12-month control period, measurements are also taken twice per month, resulting in a total of 24 turbidity data points per monitoring point; the total of 8 monitoring points, resulting in 8*2*24 turbidity data points, is averaged and recorded as the pipeline network turbidity mean ZD′. 管网均值 In this embodiment, ZD′ 管网均值 It is 0.42 NTU.

[0159] 5B. Analyze the turbidity data measured at each pipeline monitoring point during the monitoring period and the control period, and find those turbidity values ​​lower than the pipeline network average turbidity ZD′. 管网均值 The number of occurrences (C′) is shown in Tables 3 and 6, respectively.

[0160] 5C. Calculate the turbidity correction value B1′ for each pipeline monitoring point in the monitoring period and control period according to formula (1A).

[0161] B1′=C / (L×f) (1A)

[0162] In formula (1A): B1′ is the turbidity correction coefficient for each monitoring point; C′ is the turbidity value of each pipeline monitoring point that is lower than the average turbidity ZD′ of the pipeline network in the turbidity data measured during the monitoring period and the control period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring cycle or control cycle; f is the monitoring frequency, times / month; in this embodiment, L = 12 months; f = 2.

[0163] Taking the first pipeline monitoring point N1 as an example, the turbidity value of this monitoring point was lower than ZD′ in 13 out of 24 turbidity monitoring values ​​during the control period. 管网均值 0.42 NTU, therefore, the turbidity correction factor for the first pipeline monitoring point within the control period is calculated according to formula (1A).

[0164] B1′ = Turbidity less than ZD′ in the water quality monitoring data of the first pipeline monitoring point within the reference period. 管网均值 Number of monitoring sessions / Total number of monitoring sessions during the first pipeline control cycle = 13 / 24 = 0.5417 (1A)

[0165] Of the 24 turbidity monitoring values ​​recorded at this pipeline monitoring point during the monitoring period, 21 showed turbidity values ​​lower than ZD′. 管网均值 0.42 NTU, therefore, the turbidity correction factor for the first pipeline monitoring point within the monitoring period is calculated according to formula (1A).

[0166] B1′ = Turbidity less than ZD′ in the water quality monitoring data of the first pipeline monitoring point during the monitoring period. 管网均值 Number of monitoring sessions / Total number of monitoring sessions in the first pipeline monitoring cycle = 21 / 24 = 0.875 (1A)

[0167] Similarly, the B1′ values ​​of monitoring point N2-8 during the control period and monitoring period were calculated, and the measurement results are shown in Table 6.

[0168] 6. Calculate the colony correction value B2′ for each monitoring point within the monitoring period and control period.

[0169] 6A. Calculate the average total number of bacterial colonies measured at all selected pipeline monitoring points within the water quality assessment area during the monitoring and control periods. This is the average of all total bacterial colony data measured at all selected pipeline monitoring points during the monitoring and control periods (denoted as the pipeline colony mean JL′). 管网均值 );

[0170] The mean of all colony data measured at all pipeline monitoring points within the monitoring and control periods is the pipeline colony mean, denoted as JL′. 管网均值In this embodiment, for each pipeline monitoring point, measurements were taken twice per month within a 12-month monitoring period, resulting in a total of 24 colony counts per monitoring point; within a 12-month control period, measurements were taken twice per month, resulting in a total of 24 colony counts per monitoring point; for the 8 monitoring points, a total of 8*2*24 colony counts were collected, and the average value was taken, which was recorded as the pipeline colony mean JL′. 管网均值 In this embodiment, JL′ 管网均值 It is 1.46 NTU.

[0171] 6B. For each selected pipeline monitoring point, in the monitoring period and control period, the total bacterial count data were statistically analyzed, and the total bacterial count value was lower than the pipeline network average value JL′. 管网均值 The number of occurrences (D′) and the statistical results are shown in Tables 3 and 6;

[0172] 6c. Calculate the colony correction value B2′ for each monitoring point in the pipeline network during the monitoring period and the control period, respectively, according to formula (2A).

[0173] B2′=D′ / (L×f) (2A)

[0174] In formula (2A): B2′ is the colony correction coefficient for each monitoring point; D′ represents the colony count at each pipeline monitoring point that is lower than the average colony count of the pipeline network in both the monitoring and control periods. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring cycle or control cycle; f is the monitoring frequency, times / month; in this embodiment, L = 12 months; f = 2.

[0175] Taking the first pipeline monitoring point N1 as an example, the colony values ​​detected at this monitoring point were lower than JL′ in 22 out of 24 colony monitoring values ​​during the control period. 管网均值 1.46 CFU / mL; the colony correction factor B2′ for monitoring point N1 during the control period was 22 / 24 = 0.9167; the colony values ​​detected at this monitoring point in the pipeline network were lower than JL′ in 24 out of 24 colony monitoring values ​​during the monitoring period. 管网均值 1.46 CFU / mL, the colony correction factor B2′ for monitoring point N1 during the monitoring period is 24 / 24 = 1. Similarly, the B2′ values ​​for monitoring point N2-8 during the control and monitoring periods are shown in Table 6.

[0176] 7. Calculate the water quality score for each monitoring point.

[0177] Calculate the water quality score for each monitoring point in the pipeline network during the monitoring period and the control period according to formula (3A).

[0178]

[0179] In formula (3A): score is the water quality score of each monitoring point in the regional network during the monitoring period or control period; ZDi is the turbidity value of the water quality measured at each monitoring point in the regional network during the monitoring period and control period, respectively, in NTU; JLi is the total bacterial count measured at each monitoring point in the regional network during the monitoring period and control period, respectively, in CFU / mL; ZD 点均值 The mean of all turbidity values ​​measured at each monitoring point within the regional pipeline network during the monitoring period and the control period, NTU; JL 点均值 ZD represents the mean total bacterial count (CFU / mL) at each monitoring point within the regional pipe network during both the monitoring and control periods. 点偏差 The standard deviation of all turbidity readings at each monitoring point within the regional pipeline network during the monitoring period and the control period, respectively; JL 点偏差 is the standard deviation of the total bacterial count at each monitoring point within the regional pipe network during the monitoring period or control period; n is the total number of monitoring times at each monitoring point within the monitoring period or control period, n = L × f, where L is the number of natural months corresponding to the monitoring period or control period; f is the monitoring frequency; in this embodiment, L = 12, f = 2, n = 24; i is the order of the number of water quality measurements at each monitoring point within the monitoring period or control period, with i values ​​ranging from 1 to n; B1′ is the turbidity correction coefficient, indicating that the turbidity value at each monitoring point within the monitoring period or control period is less than the average turbidity monitoring data of all monitoring points within the monitoring period and control period (i.e., the average turbidity of the pipe network, ZD′). 管网均值 The ratio of the number of times the turbidity value measured at a monitoring point is lower than the average turbidity value of the entire network during the monitoring or control period to the total number of monitoring times at that monitoring point during the monitoring or control period; that is, the ratio of the number of times the measured turbidity value at a monitoring point is lower than the average turbidity value of the entire network during the monitoring or control period to the total number of monitoring times at that monitoring point during the monitoring or control period; B2′ is the colony correction factor, which indicates that the total number of colonies at each monitoring point during the monitoring or control period is less than the average total number of colonies at all monitoring points during the monitoring and control periods (i.e., the average colony count of the entire network, JL′). 管网均值 The ratio of the number of times the total number of colonies measured at a monitoring point is lower than the average number of colonies in the monitoring or control period to the total number of water quality monitoring at that monitoring point during the monitoring or control period; that is, the ratio of the number of times the total number of colonies measured at a monitoring point in the monitoring or control period is lower than the average number of colonies in the monitoring or control period to the total number of monitoring at that monitoring point during the monitoring or control period.

[0180] The water quality scores of monitoring points N1-8 were calculated according to formula (3) during the control period and the monitoring period, and the results are shown in Table 6.

[0181] The data in Example 1 are the water quality data of 8 pipeline monitoring points before the water source switch. The corresponding water quality data after the water source switch are listed in Tables 4 and 5. The water quality scores of the 8 pipeline monitoring points after the water source switch are compared with those before the switch, and the results are listed in Table 6. From the pipeline water quality data of one year before and after the water source switch, the overall water quality of the pipeline network improved after the switch. The water quality scores of monitoring points N1-4 and 7-8 improved significantly, indicating that the water quality of the pipeline network at these points improved significantly after the water source switch. The scores of monitoring points 5 and 6 did not change significantly. From the water quality data, there was no significant change in turbidity and total bacterial count after the water source switch. Therefore, the water quality of the pipeline network improved and became more stable after this water source switch, indicating that this water source switch plan is suitable for the pipeline network conditions in this area.

[0182] Table 6. Water quality scores of the pipe network before and after water source switching in a certain area.

[0183]

Claims

1. A method for evaluating the water quality of a pipe network, characterized in that, Includes the following steps: 1) Among the water quality monitoring points in the water supply area of ​​the water supply plant, N monitoring points are randomly selected, and water samples are collected at each selected monitoring point during the monitoring period. At the same time, the water quality of the water samples is measured, wherein the measured water quality refers to the turbidity and colony count of the water samples. 2) Calculate the average value and standard deviation of water turbidity and total bacterial count at each monitoring point in the pipeline network during the monitoring period. The average turbidity at each monitoring point during the monitoring period is recorded as the average turbidity value ZD. 点均值 The corresponding standard deviation is denoted as the standard deviation of turbidity at the monitoring point, ZD. 点偏差 The average number of colonies at each monitoring point during the monitoring period is recorded as the monitoring point colony mean JL. 点均值 The corresponding standard deviation is denoted as the standard deviation of colonies at the monitoring point JL. 点偏差 ; 3) Calculate the water quality score for each monitoring point in the pipeline network during the monitoring period according to formula (3). （3） In formula (3): score is the water quality score of each monitoring point in the regional pipe network; ZDi is the turbidity value of the water quality measured at each monitoring point in the regional pipe network during the monitoring period, NTU; JLi is the total number of colonies measured at each monitoring point in the regional pipe network during the monitoring period, CFU / mL; ZD 点均值 , is the average of all turbidity readings at each monitoring point within the regional pipeline network during the monitoring period, NTU; JL 点均值 ZD represents the average total bacterial count (CFU / mL) at each monitoring point within the regional pipe network during the monitoring period. 点偏差 , which represents the standard deviation of all turbidity readings at each monitoring point within the regional pipeline network during the monitoring period; JL 点偏差 , where B1 is the standard deviation of the total bacterial count at each monitoring point within the regional pipeline network during the monitoring period; B2 is the turbidity correction coefficient; B2 is the bacterial count correction coefficient; n is the total number of monitoring times at each monitoring point within the monitoring period, n = L × f, where L is the number of natural months corresponding to the monitoring period; f is the monitoring frequency; and the turbidity correction coefficient B1 is determined according to the following method: 3A) Calculate the average of all turbidity values ​​measured at all N selected pipeline monitoring points within the water quality assessment area during the monitoring period. That is, the average of all turbidity values ​​measured at all selected pipeline monitoring points during the monitoring period, denoted as the pipeline turbidity mean ZD. 管网均值 ; 3B) Statistically analyze the turbidity data measured at each selected pipeline monitoring point within the monitoring period, noting that the turbidity value is lower than the average turbidity value ZD of the pipeline network. 管网均值 The number of times C; 3C) Calculate the turbidity correction value B1 for each pipeline monitoring point according to formula (1). B1 = C / (L × f) (1) In formula (1): B1 is the turbidity correction coefficient for each monitoring point; C is the turbidity value of each pipeline monitoring point that is lower than the average turbidity ZD of the pipeline network during the monitoring period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring period; f is the monitoring frequency, times / month; The colony correction factor B2 was determined according to the following method: 3a) Calculate the average total number of bacterial colonies measured at all N selected pipeline monitoring points within the water quality assessment area during the monitoring period. That is, the average of all total bacterial colony data measured at all selected pipeline monitoring points during the monitoring period, denoted as the pipeline colony mean JL. 管网均值 ; 3b) Statistically analyze the total bacterial count data of each selected pipeline monitoring point during the monitoring period, where the total bacterial count value is lower than the pipeline network average. 管网均值 The number of times D; 3c) Calculate the colony correction value B2 for each pipeline monitoring point according to formula (2). B2 = D / (L × f) (2) In formula (2): B2 is the colony correction coefficient for each monitoring point; D is the colony value of each monitoring point in the pipeline network that is lower than the average colony value of the pipeline network during the monitoring period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring period; f is the monitoring frequency, times / month; 4) Based on the water quality score value of each pipeline monitoring point calculated in step 3), determine the quality of the water at the monitoring point; the higher the water quality score value, the better the water quality at the monitoring point.

2. A method for evaluating the water quality of a pipe network, characterized in that, Includes the following steps: 1) After the water source is switched, the treatment process or treatment parameters are adjusted at the water supply plant, N monitoring points are randomly selected from the water quality monitoring points in the water supply area of ​​the pipeline network to be evaluated, and water samples are collected at each selected monitoring point during the monitoring period. At the same time, the water quality of the water samples is measured, wherein the measured water quality refers to the turbidity and colony count of the measured water samples. 2) Review and retrieve water quality data from N monitoring points (the same as those in step 1) within the same water supply area of ​​the same pipeline network to be evaluated, before the water source switch, treatment process, or treatment parameter adjustment at the water supply plant, at the same monitoring frequency during the control period. 3) Calculate the average value and standard deviation of water turbidity and total bacterial count at each monitoring point in the monitoring and control periods. The average turbidity at each monitoring point in the monitoring and control periods is recorded as the average turbidity value at the monitoring point, ZD. 点均值 The corresponding standard deviation is denoted as the standard deviation of turbidity at the monitoring point, ZD. 点偏差 The average number of colonies at each monitoring point during the monitoring and control periods is recorded as the average colony count at the monitoring point. 点均值 The corresponding standard deviation is denoted as the standard deviation of colonies at the monitoring point JL. 点偏差 ; 4) Calculate the water quality score for each monitoring point in the pipeline network during the monitoring period and the control period according to formula (3A). （3A） In equation (3A), The score represents the water quality score of each monitoring point in the regional pipe network during the monitoring or control period; ZDi represents the turbidity value (NTU) of the water quality measured at each monitoring point in the regional pipe network during the monitoring or control period; JLi represents the total bacterial count (CFU / mL) of the total bacterial count measured at each monitoring point in the regional pipe network during the monitoring or control period; ZD 点均值 , is the average of all turbidity values ​​measured at each monitoring point within the regional pipeline network during the monitoring or control period, NTU; JL 点均值 ZD is the average total bacterial count (CFU / mL) at each monitoring point within the regional pipe network during the monitoring or control period. 点偏差 , is the standard deviation of all turbidity test values ​​at each monitoring point within the regional pipeline network during the monitoring or control period; JL 点偏差 , where B1′ is the standard deviation of the total bacterial count at each monitoring point within the regional pipeline network during the monitoring or control period; B2′ is the turbidity correction coefficient; B2′ is the bacterial count correction coefficient; n is the total number of monitoring times at each monitoring point within the monitoring or control period, n = L × f, where L is the number of natural months corresponding to the monitoring or control period; f is the monitoring frequency; and the turbidity correction coefficient B1′ is determined according to the following method: 4A) Calculate the average of all turbidity values ​​measured at all N selected pipeline monitoring points within the water quality assessment area during the monitoring and control periods. That is, the average of all turbidity values ​​measured at all selected pipeline monitoring points during the monitoring and control periods, denoted as the pipeline turbidity mean ZD′. 管网均值 ; 4B) Statistically analyze the turbidity data measured at each selected pipeline monitoring point during the monitoring period and control period, and find those turbidity values ​​lower than the pipeline network average turbidity ZD′. 管网均值 The number of times C′; 4C) Calculate the turbidity correction value B1′ for each pipeline monitoring point in the monitoring period and control period according to formula (1A). B1′ = C ′ / (L × f) (1A) In formula (1A): B1′ is the turbidity correction coefficient for each monitoring point; C′ is the turbidity value of each pipeline monitoring point that is lower than the average turbidity ZD of the pipeline network in the turbidity data measured during the monitoring period or control period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring cycle or control cycle; f is the monitoring frequency, times / month; The colony correction factor B2′ was determined according to the following method: 4a) Calculate the average total number of bacterial colonies measured at all N selected pipeline monitoring points within the water quality assessment area during the monitoring and control periods. That is, the average total number of bacterial colonies measured at all selected pipeline monitoring points during the monitoring and control periods, denoted as the pipeline colony mean JL′. 管网均值 ; 4b) Statistically analyze the total bacterial count data of each selected pipeline monitoring point during the monitoring period and control period, and find that the total bacterial count value is lower than the pipeline network average value JL′. 管网均值 The number of times D′; 4c) Calculate the colony correction value B2′ for each pipeline monitoring point in the monitoring period and control period according to formula (2A). B2 ′= D′ / (L × f) (2A) In formula (2A): B2′ is the colony correction coefficient for each monitoring point; D′ is the colony value at each pipeline monitoring point that is lower than the average colony value JL′ of the pipeline network in the total colony count data measured during the monitoring period and control period. 管网均值 The number of times; L is the number of natural months corresponding to the monitoring cycle or control cycle; f is the monitoring frequency, times / month; 5) Based on the water quality score calculated in step 4), determine the quality of the water at each monitoring point; the higher the water quality score, the better the water quality at that monitoring point.

3. The method as described in claim 1 or 2, characterized in that, The number of water quality monitoring points selected in step 1) is N ≥ 5.

4. The method as described in claim 1 or 2, characterized in that, The number of water quality monitoring points N selected in step 1) is 6-20.

5. The method as described in claim 1 or 2, characterized in that, The number of water quality monitoring points N selected in step 1) is 8.

6. The method as described in claim 1, characterized in that, The turbidity was determined by the scattering method in "Standard Examination Methods for Drinking Water - Sensory Characteristics and Physical Indicators"; the total bacterial count was determined by the plate counting method in "Standard Examination Methods for Drinking Water - Microbiological Indicators".

7. The method as described in claim 1 or 2, characterized in that, The monitoring period described in step 1) is ≥ 6 consecutive natural months.

8. The method as described in claim 1 or 2, characterized in that, The monitoring period described in step 1) is 6-12 consecutive calendar months.

9. The method as described in claim 1 or 2, characterized in that, The monitoring period described in step 1) is 12 consecutive natural months.

10. The method as described in claim 1 or 2, characterized in that, In step 1), the water sample monitoring frequency at each water quality monitoring point is at least 2 times per month during the monitoring period. That is, during the monitoring period, water samples are collected and water quality is measured at each water quality monitoring point at least 2 times per natural month.

11. The method as described in claim 1 or 2, characterized in that, In step 1), the water sample monitoring frequency at each water quality monitoring point is 2-4 times per month during the monitoring period. That is, during the monitoring period, water samples are collected and water quality is measured at each water quality monitoring point 2-4 times per natural month.

12. The method as described in claim 2, characterized in that, The control period mentioned in step 2) is ≥6 consecutive calendar months.

13. The method as described in claim 2, characterized in that, The control period mentioned in step 2) is 6-12 consecutive calendar months.

14. The method as described in claim 2, characterized in that, The control period mentioned in step 2) is 12 consecutive calendar months.

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