JP2014106146A - Drain deterioration determination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drain deterioration determination method which can accurately determine a deteriorate state of an entire drain such as a water pipe and is implemented at a cheap cost.SOLUTION: A drain deterioration determination method comprises: a water sampling process to extract water samples from a drain at different locations separated each other in a flow direction; a concentration measuring process to measure concentrations of suspended elements by analyzing the same contained in the extracted water samples; a variation measuring process to measure variations of the suspended elements on the basis of the concentrations thereof in the different water samples; and a water quality analyzing process to analyze water quality on the basis of the variations of the measured concentrations of the suspended elements. Because the water samples are extracted from locations separated each other in the flow direction of the drain and the water quality is analyzed on the basis of the variations of the concentrations of the suspended elements in the water samples, the drain deterioration determination method can determine deterioration of the entire drain from an upper reach to a lower reach thereof.

Description

  The present invention relates to a method for determining aging of a water pipe used for judging the renewal time of a water pipe such as a water pipe.

  Although water pipes are buried nationwide as a lifeline to maintain the people's lives, corrosion and deterioration occur in the water pipes due to aging, and therefore, the existing water pipes will be renewed sequentially. There is a need. Here, if the corrosion and deterioration of the water pipe is proportional to the age of burial, it may be updated in order according to the number of years of aging, but the degree of corrosion and deterioration depends on the material of the water pipe, the burial environment of the water pipe, Depending on the quality of the water flowing in the pipe, etc., on the other hand, even if the method of sequentially performing the embedment age is adopted, this method may also be adopted if the plumbing records of the water pipe are not properly managed. Can not.

  Therefore, conventionally, a method of determining the aging by measuring the corrosion depth of the outer surface of the buried water pipe (Patent Document 1), or measuring the shock wave accompanying the interruption by blocking the flow of the water pipe and measuring the water A method for determining deterioration of a pipe (Patent Document 2) has been proposed.

JP 2007-107882 A JP 2010-230418 A

  However, in the former judgment method among the conventional aging judgment methods, it is necessary to dug at least part of the water pipe in order to inspect the external corrosion of the water pipe buried in the ground, and the judgment method is expensive. On the other hand, in the latter determination method, a shock wave generator is required to generate a shock wave, and the determination structure is extremely expensive. In addition, there was a problem that the aging status of the entire water pipe cannot be grasped only by inspecting a part of the water pipe in the former determination method.

  An object of the present invention is to provide a method for determining the deterioration of a distribution pipe that can accurately determine the deterioration status of the entire distribution pipe, such as a water pipe, in view of the above-described conventional problems, and that also reduces the cost.

  In order to solve the above-mentioned problem, the method for determining aging of a water pipe according to the present invention includes a water sampling step of collecting a water sample of the water pipe from different locations separated in the flow direction, and a suspended state included in the collected water sample. A concentration measurement process for analyzing elements and measuring the concentration of suspended elements; a change measurement process for measuring changes in suspended element concentrations based on suspended element concentrations of different water samples; And a water quality analysis process for performing water quality analysis based on the amount of change in turbid element concentration.

  According to the present invention, since a water sample flowing in a water pipe, for example, a water pipe, is an object to be tested, it can be collected from a fire hydrant or an air valve connected to the water pipe, so that the sample can be easily obtained. In addition, since the water sample is collected from a location separated in the flow direction of the water pipe and the water quality analysis is performed based on the amount of change in the suspended element concentration of the water sample, the entire water pipe extending from the upstream to the downstream of the water pipe Can be judged as aging.

  Note that multivariate analysis (principal component analysis) may be adopted as the water quality analysis. In this case, the first main component is at least a suspended element (Fe, Al, or Mn) caused by the corrosion product. 1), and the second main component is a suspended element (Ca) due to deterioration of the mortar lining.

  According to the present invention, it is possible to accurately determine the deterioration state of the entire water pipe, and the cost is reduced in the determination of aging of the water pipe.

Process chart showing aging judgment method of water pipe Schematic showing the arrangement structure of water pipes Table showing summary of each water pipe Table showing factor loading of each main component Main component score table for each water pipe

  1 to 5 show an embodiment of a method for determining aging of a water pipe (water pipe) according to the present invention.

  The process of this aging determination method is as shown in FIG.

  First, the water sampling process A which collects a water sample from two points of the flow direction of a water pipe is performed. In this water sampling step 10, for example, tap water (water sample) is collected from different locations separated in the flow direction of the water pipe. Specifically, a water sample is taken from a fire hydrant or an air valve connected upstream and downstream of the water pipe. There are several possible timings for collecting a water sample, such as when the hydrant is opened, 5 minutes after opening, or 15 minutes after opening, but water at the time of opening the hydrant contains substances due to corrosion of the hydrant itself. Therefore, in order to avoid the effects of fire hydrant corrosion, for example, the sample may be collected after 15 minutes have elapsed since opening. In addition, if the amount of water collected from the water sample can be analyzed with a small amount of collection material, a small amount of water, for example, about 1 L (liter) is not a problem. For example, about 30L may be collected.

  Next, the process proceeds to a collection step B where a suspension is collected from the collected water sample. As a method for collecting the suspension, for example, the water sample is filtered using the membrane filter and the 1-30 L water sample is filtered to collect the suspension.

  Subsequently, the process proceeds to a measurement step C of the suspended element concentration of the collected suspension. In this process, the collected suspension is dissolved in advance using nitric acid or perchloric acid, and this dissolved suspension is analyzed with an inductively coupled plasma (ICP) device to measure the concentration of suspended elements. . As this ICP device, an ICP emission spectroscopy (AES) device or an ICP mass spectrometry (MS) device is used, and Al, Si, Ca, Mn, Fe, and Zn are analyzed by these devices. The concentration of these suspended elements is measured.

  Further, after measuring the suspended element concentration, the process proceeds to a measuring step D for measuring the amount of change in suspended element concentration. Suspensions are mixed into the tap water from the water pipe. In this measurement step D, from the upstream from the suspended element concentration of the water sample collected from the downstream of the water pipe in order to analyze the degree of contamination of the suspended elements. The suspended water element concentration of the collected water sample was subtracted and measured. The concentration was calculated after setting the value to 0 (zero) for the concentration below the limit of quantification, and when the value became negative by the subtraction, the value was calculated as 0 (zero).

  Finally, the process proceeds to the water quality analysis step E using the change amount of the suspended element concentration. In this water quality analysis step E, analysis is performed by multivariate analysis, for example, principal component analysis. The principal component analysis was performed with statistical software.

  An example of the method for determining aging of a water pipe shown in the embodiment will be described below.

  As shown in Fig. 2, water pipes 1a and 1c that distribute water from the water purification plant to the pump station and then conduct water from the pump station to the water reservoir as shown in Fig. 2 The water pipes 1b, 1d for distributing the water of the water, and the water pipes 1e, 1f, 1g for directly distributing the water of the water purification plant.

  As shown in FIG. 3, each of the water pipes 1 a to 1 g is a variety of different pipe materials. That is, the water pipes 1a and 1c are mortar-lined steel pipes, the water pipe 1b is a steel pipe, the water pipes 1d and 1g are mortar-lined ductile iron pipes, and 1e and 1f are resin-lined cast iron pipes. The number of years after the installation of each water pipe 1a to 1g is 38 years for the water pipe 1a, 46 to 55 years for the water pipe 1b (the exact number is unknown, calculated from the approximate time), and the water pipe 1c is 41 years, water pipe 1d has been 20 years. In addition, water pipes 1e and 1f were laid in 27 and 29, respectively, in the latter half of the Showa era to the 1940s, the water pipe 1e was repaired in 1984, and the water pipe 1f was repaired in 1982 and washed and resin. The lining was implemented). Furthermore, the water pipe 1g is 21 years.

  About water pipe 1a-1g used as the above situations, water sample sampling process A (sample volume; 7L or 20L), suspension sampling process B (constant volume; 50mL), suspension concentration Measurement step C (using ICP-AES) and measurement step D of suspended element concentration change were sequentially performed, and water quality analysis step E (principal component analysis) was performed.

  The result of the principal component analysis is as shown in FIG. The contribution ratio of each component was 43% for the first principal component and 36% for the second principal component, and the cumulative contribution ratio of the first and second principal components was 79%. In addition, the factor loading of each main component is as shown in FIG.

  Depending on the factor loading, the first principal component has a strong positive correlation with Al (0.83), Mn (0.93), and Fe (0.85), and the second principal component is Ca (−0). .9) and the negative correlation is strong. As the increase factor of the suspension concentration, it can be seen that the first main component is influenced by the peeling of the corrosion product, and the second main component shows the influence of the lining containing a large amount of Ca.

  As described above, according to the method for determining aging of water pipes according to the present invention, the aging status of various water pipes 1a to 1g can be clearly determined by the water quality analysis step E, and the analysis thereof. Is based on water samples collected from different locations separated in the flow direction of the water pipes 1a to 1g, so that each water pipe 1a to 1g can accurately determine the aging status of the whole pipe.

  Further, unlike the conventional aging determination method, the work of digging up the water pipe is not necessary, and a large-scale device such as a shock wave generator is not required, so that it is also cheaper in terms of cost.

  Further, as a result of the water quality analysis step E, as shown in FIG. 5, the results divided according to the pipe type, that is, mortar lining steel pipes 1a and 1c, mortar lining ductile iron pipes 1d and 1g, and resin lining cast iron pipes 1f and 1g, respectively. Since the results are divided, even if the pipe type of the buried water pipe is unknown, it can be used for pipe type determination of the water pipe by this determination method.

  Although the principal component analysis is used as the multivariate analysis, a multidimensional scale construction method may be used.

  1a-1g ... water pipe.

Further, after measuring the suspended element concentration, the process proceeds to a measuring step D for measuring the amount of change in suspended element concentration. Suspensions are mixed into the tap water from the water pipe. In this measurement step D, from the upstream from the suspended element concentration of the water sample collected from the downstream of the water pipe in order to analyze the degree of contamination of the suspended elements. The suspended water element concentration of the collected water sample was subtracted and measured. Note that the concentration of the following quantitative limits and density calculations the values upon which the 0 (zero).

Claims (5)

A water sampling process for collecting water samples from different locations separated in the flow direction of the water pipe;
A concentration measurement step of analyzing suspended elements contained in the collected water sample and measuring the concentration of suspended elements;
A change amount measuring step for measuring a change amount of the suspended element concentration based on the suspended element concentration of different water samples;
A method for determining aging of distribution pipes, comprising a water quality analysis step for performing water quality analysis based on the measured change in suspended element concentration. The method according to claim 1, wherein the water quality analysis is multivariate analysis. 3. The method for determining aging of a water pipe according to claim 2, wherein principal component analysis is used as the multivariate analysis. In the principal component analysis, the first principal component is a suspended element caused by a corrosion product, and the second principal component is a suspended element caused by mortar lining deterioration. To determine the aging of water pipes. The aging determination method for a water pipe according to claim 4, wherein the first main component is at least one of Fe, Al, or Mn, and the second main component is Ca.

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