Sewerage maintenance management system, sewerage maintenance management method

Abstract

This device detects whether the concrete surface of a sewage treatment facility is in a condition prone to deterioration. [Solution] The present invention relates to a sewer maintenance management system and a sewer maintenance management method for sewer facilities having a concrete surface. The sewer maintenance management system comprises a pH sensor and a liquid properties determination device. The pH sensor detects the pH value of the concrete surface. The liquid properties determination device outputs a predetermined alarm when it meets predetermined conditions indicating that the pH value is acidic. The sewer maintenance management method comprises a pH sensor installation step, a pH value acquisition step, and a liquid properties determination step, with the pH value acquisition step and the liquid properties determination step being repeated. The pH sensor installation step involves attaching the pH sensor to the gas phase portion of the concrete surface. The pH value acquisition step involves detecting the pH value of the concrete surface with the pH sensor. The liquid properties determination step involves the liquid properties determination device outputting a predetermined alarm when it meets predetermined conditions indicating that the pH value is acidic.

Description

Technical Field

[0001] The present invention relates to a sewer maintenance management system and a sewer maintenance management method for supporting the maintenance and management of sewer facilities having a concrete surface.

Background Art

[0002] Non-Patent Document 1 shows considerations on the relationship between pH and SO4 2- concentration and the deterioration mechanism and erosion rate of concrete. Patent Document 1 shows a sulfuric acid-resistant concrete structure, particularly a sulfuric acid corrosion-resistant concrete pipe suitable for sewer pipes, a method for preventing sulfuric acid corrosion of concrete pipes, and a method for preventing corrosion of reinforcing bars. In the problems of the summary of Patent Document 2, it is shown that "in the water tank of a sewer treatment facility, sulfate ions present in the sewage are changed into hydrogen sulfide by anaerobic sulfur-reducing bacteria, diffused into the air, redissolved in the dew water on the concrete surface, and become sulfuric acid by aerobic sulfur-oxidizing bacteria. The cement hydrate is dissolved and deteriorated by this sulfuric acid, and the concrete deteriorates." As a solution, it is shown that "it consists of a water supply pipe, a control valve, a pipe inside the water tank, and a sprinkler. A control valve is attached in the middle of the water supply pipe installed outside the water tank, and sprinklers are attached in the middle and at the end of the water supply pipe installed inside the water tank. By operating the control valve, water is discharged from the sprinkler to wash the ceiling and wall surfaces inside the water tank." Patent Document 3 shows that the pH inside the concrete can be quantitatively measured. Particularly, in paragraph 0029, it is described that "the pH detection electrode wire 70 is a sensor for measuring the pH of the concrete structure 10 and can be manufactured by forming a metal oxide on a metal. The material metals of the pH detection electrode wire 70 include tungsten, iron, nickel, copper, and iridium. Since the concrete is strongly alkaline, it is an essential requirement for the material metal of the pH detection electrode wire 70 to be stable without dissolving in this. Among these, as shown in the examples, the W / WOx electrode manufactured using tungsten has high stability and high accuracy in a concrete simulation solution (Ca(OH)2).".

Prior Art Documents

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-007626 [Patent Document 2] Japanese Patent Publication No. 2005-138067 [Patent Document 3] Japanese Patent Publication No. 2020-034563 [Non-patent literature]

[0004] [Non-Patent Document 1] Natsuki Yoshida, Kenichi Nakayama, Akihiko Yamanaka, and Toshiro Kamata, "Consideration of the Chemical Erosion Mechanism of Concrete Based on the Survey Results of Sewer Pipelines in Osaka City," GBRC, Vol.42 No.3, pp.15-20, July 2017, [Retrieved January 29, 2025], Internet<https: / / www.gbrc.or.jp / assets / documents / gbrc / GBRC169_828.pdf> . [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the technology described in Patent Document 1 cannot be used as is in existing sewage facilities and requires modification of the sewage facilities. With the technology described in Patent Document 2, the timing of watering is unknown, so watering may not be performed until the next watering time even when prompt watering is required. In addition, watering may be wasted. The technology described in Patent Document 3 aims to provide suitable salinity sensors and pH sensors, and is not intended for the maintenance and management of sewage facilities themselves. The present invention aims to detect whether the concrete surface of a sewage facility is in a state where it is prone to deterioration. [Means for solving the problem]

[0006] The present invention relates to a sewer maintenance management system and a sewer maintenance management method for sewer facilities having a concrete surface. The sewer maintenance management system comprises a pH sensor and a liquid properties determination device. The pH sensor detects the pH value of the concrete surface. The liquid properties determination device outputs a predetermined alarm when it meets predetermined conditions indicating that the pH value is acidic. The sewer maintenance management method comprises a pH sensor installation step, a pH value acquisition step, and a liquid properties determination step, with the pH value acquisition step and the liquid properties determination step being repeated. The pH sensor installation step involves attaching the pH sensor to the gas phase portion of the concrete surface. The pH value acquisition step involves detecting the pH value of the concrete surface with the pH sensor. The liquid properties determination step involves the liquid properties determination device outputting a predetermined alarm when it meets predetermined conditions indicating that the pH value is acidic. [Effects of the Invention]

[0007] According to the sewer maintenance management system and sewer maintenance management method of the present invention, the pH value of the concrete surface of a sewer facility is detected, and a predetermined alarm is output if predetermined conditions indicating that the pH value is in an acidic state are met, thereby enabling detection of whether or not the concrete surface of a sewer facility is in a state where it is prone to deterioration. [Brief explanation of the drawing]

[0008] [Figure 1] A diagram showing an example of the functional configuration of a sewer maintenance and management system. [Figure 2] A diagram showing an example of a processing flow for sewer maintenance and management methods. [Figure 3] A diagram showing a pH sensor attached to a manhole. [Figure 4] Figure 1 shows the treatment plant (pond structure) with a pH sensor, sprinkler system, and water level gauge installed. [Figure 5] The second diagram shows the treatment plant (pond structure) with a pH sensor, sprinkler system, and water level gauge installed. [Figure 6] A diagram showing an example of how to install a pH sensor. [Figure 7] A diagram illustrating the concept of a calibration curve created using standard solutions. [Figure 8]Figure 1 shows an image of the predetermined conditions and alarm output. [Figure 9] The second figure shows an image of the specified conditions and alarm output. [Modes for carrying out the invention]

[0009] First, let's explain the mechanism of degradation. The degradation mechanism of sulfuric acid corrosion proceeds through the following process. (1) Due to the action of sulfate-reducing bacteria living in sewage, sulfate ions (SO4) contained in sewage are reduced 2- The first process involves the reduction of ) to produce hydrogen sulfide (H2S), which is then released into the air. (2) Subsequently, this hydrogen sulfide (H2S) dissolves in moisture such as condensation water adhering to the concrete surface, and H2SO4 is produced by sulfur-oxidizing bacteria living on the concrete surface, which is the second process that degrades the concrete surface in the gas phase.

[0010] This invention focuses on the second process described above and attempts to suppress the deterioration of the concrete surface by spraying water on the concrete surface. The changes in the concrete surface due to water spraying are shown below. (1) When water is sprayed on the concrete surface, H2SO4 is diluted, the pH rises to near neutral, and the progression of deterioration is temporarily slowed down. (2) If watering is stopped before it is sufficient, the pH of the concrete surface will drop again due to the newly generated H2SO4, and deterioration will progress. (3) After the concrete surface dries, the area of ​​the H2SO4 aqueous solution in contact with the concrete surface decreases, and the H2SO4 becomes concentrated. (4) When condensation water adheres to the concrete surface, the concrete surface changes from a dry state to a wet state, concentrated H2SO4 spreads across the concrete surface, and the pH decreases due to newly generated H2SO4, causing deterioration to progress.

[0011] From the above mechanism, in the present invention, the pH of the concrete surface is continuously measured, and in order to prevent the pH of the concrete surface from decreasing in a timely manner, the deterioration of the concrete surface is suppressed by outputting an alarm indicating that watering is necessary or by controlling watering.

[0012] Hereinafter, embodiments of the present invention will be described in detail. Components having the same function are denoted by the same reference numerals, and redundant descriptions are omitted. Also, in this specification, N is an integer of 1 or more, and n is an integer of 1 or more and N or less.

Example

[0013] FIG. 1 is a diagram showing a functional configuration example of a sewer maintenance management system. FIG. 2 is a diagram showing an example of a processing flow of a sewer maintenance management method. The sewer facilities in this specification include manholes, sewer pipelines such as sewer pipes, and treatment plants (tank structures). FIG. 3 is a diagram showing a state where a pH sensor is attached to a manhole, and FIGS. 4 and 5 are diagrams showing a state where a pH sensor, a watering device, and a water level gauge are attached to a treatment plant (tank structure).

[0014] The sewer maintenance management system 11 includes at least pH sensors 200-1, ..., N and a liquid type determination device 100. The sewer maintenance management system 11 may also include at least pH sensor 200-n in the sewer facility 900-n, and may further include a sprinkler system 300-n and a water level meter 400-n. The pH sensor 200-n, sprinkler system 300-n, and water level meter 400-n are connected to the liquid type determination device 100 by a communication line. A communication device 500-n may also be provided in the sewer facility 900-n in order to connect the pH sensor 200-n, sprinkler system 300-n, and water level meter 400-n to the liquid type determination device 100 by a communication line. If the sewer facility 900-n is a manhole, it is often sufficient to install only pH sensor 200-n. However, a water level meter 400-n may be provided to confirm whether the entire sewer pipe 910 is submerged. Furthermore, if the sewage facility 900-n is a treatment plant (pond structure), it is easier to secure tap water for watering, so it is sufficient to provide a watering device 300-n and a water level gauge 400-n. However, it is not necessary to limit it to these, and it is sufficient to decide whether or not to install the watering device 300-n and water level gauge 400-n depending on the need. For example, a water level gauge 400-n may be installed at the downstream sewage facility 900-n, and a watering device 300-(n-1) may be installed at the upstream sewage facility 900-(n-1).

[0015] The pH sensor 200-n comprises a pH measuring electrode 210-n, a reference electrode 220-n, and a signal processing unit 230-n, and is attached to the gas phase portion of the concrete surface (S202). The "gas phase portion" usually refers to the part that is not below the water surface. The pH sensor 200-n detects the pH value of the concrete surface 902-n (S201). Figure 6 shows an example of how to install the pH sensor 200-n. A tungsten wire can be used for the pH measuring electrode 210-n. The tip of the pH measuring electrode 210-n (tungsten wire) should be oxidized, and the unoxidized portion should be insulated. Oxidation can be performed by immersion in aqua regia. The reference electrode 220 can be a silver-silver chloride electrode filled with an aqueous potassium chloride solution (for example, 3 mol / L) as the internal liquid. In the pH sensor installation step (S202), a hole 904-n is made in the concrete surface 902-n at an angle downwards, tap water 291-n is poured into the hole 904-n, the reference electrode 220-n is inserted so as to contact a part of the hole 904-n, and the pH measuring electrode 210-n is installed so that the tip part contacts the concrete surface 902-n.

[0016] The signal processing unit 230-n converts the electrical signals (voltages) obtained from the pH measuring electrode 210-n and the reference electrode 220-n into pH values. For example, the signal processing unit 230-n can be configured by connecting the pH measuring electrode 210-n to the positive side of a voltmeter, connecting the signal processing unit 230-n to the negative side of the voltmeter, and measuring the potential difference between the pH measuring electrode 210-n and the reference electrode 220-n. The signal processing unit 230-n can also be configured by pre-recording a calibration curve 14 using a standard solution to convert electrical signals (voltages) into pH values. Then, the pH value can be determined based on the obtained electrical signals (voltages). Figure 7 shows an image of the calibration curve created using a standard solution. In Figure 7, the horizontal axis represents the pH value and the vertical axis represents the electrical signal (voltage).

[0017] If a sprinkler system 300-n is also installed, it should be installed in a position that wets the gas phase section of the sewage facility 900-n (S302). Then, when the liquid type determination device 100 outputs an alarm, the sprinkler system 300-n should sprinkle water according to a predetermined schedule (S301). "Predetermined sprinkling" may mean that the sprinkling time is predetermined, or the amount of water to be sprinkled is predetermined. Alternatively, sprinkling may be based on the pH value acquired by the pH sensor 200-n. Figure 4 shows the case where the sprinkler system 300-n is installed on the cover 905, and Figure 5 shows the case where the sprinkler system 300-n is attached to the top of the concrete surface 902-n. The purpose of the sprinkler system 300-n is to wet the gas phase section. The structure and installation location of the sprinkler system 300-n should be determined considering the size of the sewage facility 900-n, etc.

[0018] If a water level gauge 400-n is also installed, it should be placed in a position where it can measure whether the water level in the sewage facility 900-n has exceeded a predetermined standard water level (S402). The water level gauge 400-n measures whether the water level has exceeded a predetermined standard water level (S401). Generally, concrete surfaces that are close to the water surface but not below it tend to deteriorate easily. The "standard water level" can be determined by setting the height of the concrete surface 902-n that is subject to maintenance based on the ease of deterioration and the degree of deterioration of the concrete surface 902-n, and setting that height as the "standard water level". Alternatively, a sprinkler system 300-(n-1) with a watering function may be installed in the sewage facility 900-(n-1) upstream of the sewage facility 900-n. In this case, when an alarm is output from the sewage facility 900-n, watering will begin from the sprinkler system 300-(n-1). Then, when the water level indicated by the water level gauge 400-n exceeds a predetermined standard water level, the alarm and water spraying should be stopped. For example, if the "predetermined standard water level" is set to the water level at which the entire sewer pipe 910 is submerged, maintenance management including the sewer pipe 910 can be carried out.

[0019] The liquid properties determination device 100 includes a communication unit 110, a determination unit 120, an output unit 130, and a recording unit 190, and outputs a predetermined alarm when predetermined conditions indicating that the pH value is acidic are met (S101-S103). The communication unit 110 communicates with the pH sensor 200-n, the watering device 300-n, and the water level meter 400-n. The determination unit 120 determines the liquid properties from the pH value acquired by the pH sensor 200-n (S101), and if necessary, performs processing such as outputting an alarm to the output unit 130, and records the pH value data in the recording unit 190 (S102). If maintenance management is to be continued, the liquid properties determination device 100 repeats the process (S103).

[0020] For example, the "predetermined condition" can be defined as the pH value remaining below a predetermined reference value for a predetermined first predetermined time or longer. After the predetermined condition is met, the liquid properties determination device 100 should stop outputting a predetermined alarm when the pH value remains above the reference value for a predetermined second predetermined time or longer. An image of this process is shown in Figure 8. In Figure 8, the horizontal axis represents time, and the vertical axis represents the pH value. The liquid properties determination device 100 records the reference value 21 in the recording unit 190. The liquid properties determination device 100 also continuously records the pH value 22 obtained from the pH sensor 200-n in the recording unit 190. When the pH value 22 remains below the reference value (a state in which the acidity is stronger than the reference pH) for a predetermined first predetermined time T1 or longer, an alarm output 23 is output. Then, when the pH value 22 remains above the reference value (a state in which the acidity is weaker than the reference pH) for a predetermined second predetermined time T2 or longer, an alarm reset 24 is performed. A "prescribed alarm" is, for example, a command to water (watering command 25). If the watering device 300-n is installed, the watering device 300-n should be instructed to water for the duration that the watering command 25 is being output. If the watering device 300-n is not installed, an alarm requesting the maintenance manager to water should be output. For example, the output unit 130 may send the alarm to a terminal owned by the maintenance manager, or the alarm may be displayed on the maintenance management display board of the organization responsible for maintenance.

[0021] Another example of a "predetermined condition" is when the sum of the periods during which the pH value is lower than a predetermined reference value is longer than a predetermined period. Figure 9 shows an image of the processing in the case of this condition. In Figure 9, the horizontal axis is time and the vertical axis is pH value. The determination unit 120 includes an addition unit 51 and an accumulated time confirmation unit 52. The liquid properties determination device 100 records the reference value 21 in the recording unit 190. The liquid properties determination device 100 also continuously records the pH value 22 obtained from the pH sensor 200-n in the recording unit 190. The addition unit 51 records the period t1, ..., t during which the pH value 22 is lower than the reference value (a state in which the pH is more acidic than the reference pH). M The sum (cumulative time) is calculated by adding the values. M is an integer greater than or equal to 1. The cumulative time confirmation unit 52 compares the added sum (cumulative time) with a predetermined period. The liquid properties determination device 100 outputs an alarm when the sum (cumulative time) exceeds the predetermined period. When a water level gauge 400-n is installed in the sewage facility 900-n, for example, if the water level indicated by the water level gauge exceeds a predetermined standard water level, the sum (cumulative time) may be reset. This is because the pH value of the concrete surface 902-n generally increases (acidity decreases) when it is submerged in water, reducing the need to output an alarm to indicate the timing of watering. Also, if an alarm has already been output, the alarm may be stopped if the water level indicated by the water level gauge 400-n exceeds a predetermined standard water level.

[0022] According to the sewer maintenance management system 11 and the sewer maintenance management method, the pH value of the concrete surface 902-1,...,N of the sewer facilities 900-1,...,N is detected, and a predetermined alarm is output if the pH value meets predetermined conditions indicating an acidic state. Therefore, it is possible to detect whether the concrete surface 902-1,...,N of the sewer facilities 900-1,...,N is in a state where it is prone to deterioration. Thus, sewer facilities can be properly maintained. [Explanation of Symbols]

[0023] 11 Sewerage Maintenance and Management System 14 Calibration Curve 21 Reference Value 22 pH Value 23 Alarm output 24 Alarm reset 25 Watering command 51 Addition section 52 Accumulation time confirmation unit 100 Liquid properties determination device 110 Communication section 120 Judgment section 130 Output section 190 Recording section 200 pH sensor, 210 pH measuring electrode 220 Reference electrode 230 Signal processing unit 291 Tap water 300 Sprinkler system 400 Water level gauge 500 Communication device 900 Sewerage facilities 902 Concrete surface 904 Hole 905 Lid 910 Sewer pipe

Claims

1. A sewerage maintenance and management system for a sewerage facility having a concrete surface, A pH sensor for detecting the pH value of the concrete surface, A liquid properties determination device that outputs a predetermined alarm when predetermined conditions indicating that the pH value is in an acidic state are met, Equipped with, The aforementioned predetermined condition is that the pH value remains below a predetermined standard value for a predetermined first predetermined period of time or longer. After the predetermined conditions are met, if the pH value remains above the standard value for a predetermined second predetermined time or longer, the liquid properties determination device will stop outputting the predetermined alarm. A sewer maintenance and management system characterized by the following features.

2. A sewer maintenance management system for a sewer facility having a concrete surface, A pH sensor for detecting the pH value of the concrete surface, A liquid properties determination device that outputs a predetermined alarm when predetermined conditions indicating that the pH value is in an acidic state are met, Equipped with, The aforementioned predetermined condition is when the sum of the periods during which the pH value is lower than a predetermined standard value is longer than a predetermined period. A sewer maintenance and management system characterized by the following features.

3. A sewer maintenance management system according to claim 1, Furthermore, it is equipped with a sprinkler system that has the function of spraying water around it. While the liquid type determination device outputs an alarm, the watering device sprays water. A sewer maintenance and management system characterized by the following features.

4. A sewer maintenance management system for a sewer facility having a concrete surface, A pH sensor for detecting the pH value of the concrete surface, A liquid properties determination device that outputs a predetermined alarm when predetermined conditions indicating that the pH value is in an acidic state are met, A water level gauge for measuring the water level within the aforementioned sewage facility Prepare, If the water level indicated by the water level gauge exceeds a predetermined reference water level, the alarm will be deactivated. A sewer maintenance and management system characterized by the following features.

5. A sewer maintenance management system according to claim 2, Furthermore, it is also equipped with a water level gauge for measuring the water level within the aforementioned sewage facility. If the water level indicated by the water level gauge exceeds a predetermined reference water level, the sum is reset. A sewer maintenance and management system characterized by the following features.

6. A sewer maintenance management system for a sewer facility having a concrete surface, A pH sensor for detecting the pH value of the concrete surface, A liquid properties determination device that outputs a predetermined alarm when predetermined conditions indicating that the pH value is in an acidic state are met, A water level gauge for measuring the water level within the aforementioned sewage facility, A sprinkler system having a watering function is installed at a sewage facility upstream of the aforementioned sewage facility. Equipped with, When the liquid type determination device outputs an alarm, the watering device starts watering. If the water level indicated by the water level gauge exceeds a predetermined standard water level, the alarm and watering will be stopped. A sewer maintenance and management system characterized by the following features.

7. A sewer maintenance management system for a sewer facility having a concrete surface, A pH sensor for detecting the pH value of the concrete surface, A liquid properties determination device that outputs a predetermined alarm when predetermined conditions indicating that the pH value is in an acidic state are met, Equipped with, The pH sensor includes a pH measuring electrode and a reference electrode. The pH measuring electrode has an oxidized tungsten wire tip, and the unoxidized portion is insulated. The aforementioned reference electrode is a silver-silver chloride electrode filled with an aqueous potassium chloride solution as the internal solution. A sewer maintenance and management system characterized by the following features.

8. A sewer maintenance method for maintaining a sewer facility having a concrete surface, A pH sensor installation step involves attaching a pH sensor, which detects the pH value, to the gas phase portion of the concrete surface. A pH value acquisition step in which the pH value of the concrete surface is detected by the pH sensor, A liquid properties determination step in which a liquid properties determination device outputs a predetermined alarm when it meets predetermined conditions indicating that the pH value is in an acidic state, It has, The pH value acquisition step and the liquid properties determination step are repeated, The aforementioned predetermined condition is that the pH value remains below a predetermined standard value for a predetermined first predetermined period of time or longer. After the predetermined conditions are met, if the pH value remains above the standard value for a predetermined second predetermined time or longer, the liquid properties determination device will stop outputting the predetermined alarm. A method for maintaining and managing sewer systems, characterized by the following features.

9. A sewer maintenance method for maintaining a sewer facility having a concrete surface, A pH sensor installation step involves attaching a pH sensor, which detects the pH value, to the gas phase portion of the concrete surface. A pH value acquisition step in which the pH value of the concrete surface is detected by the pH sensor, A liquid properties determination step in which a liquid properties determination device outputs a predetermined alarm when it meets predetermined conditions indicating that the pH value is in an acidic state, It has, The pH value acquisition step and the liquid properties determination step are repeated, The aforementioned predetermined condition is when the sum of the periods during which the pH value is lower than a predetermined standard value is longer than a predetermined period. A method for maintaining and managing sewer systems, characterized by the following features.

10. A sewer maintenance and management method according to claim 8, Furthermore, the watering device installation step involves installing the watering device in a position that wets the gas phase portion of the sewage facility, The system also includes a watering step in which the watering device sprays water while the liquid type determination device is outputting an alarm. A method for maintaining and managing sewer systems, characterized by the following features.

11. A sewer maintenance method for maintaining a sewer facility having a concrete surface, A pH sensor installation step involves attaching a pH sensor, which detects the pH value, to the gas phase portion of the concrete surface. A pH value acquisition step in which the pH value of the concrete surface is detected by the pH sensor, A liquid properties determination step in which a liquid properties determination device outputs a predetermined alarm when it meets predetermined conditions indicating that the pH value is in an acidic state, It has, The pH value acquisition step and the liquid properties determination step are repeated, Furthermore, the process includes a water level gauge installation step, which involves installing a water level gauge to measure whether the water level in the sewage facility exceeds a predetermined standard water level, The system also includes an alarm deactivation step that stops the alarm if the water level indicated by the water level gauge exceeds a predetermined reference water level. A method for maintaining and managing sewer systems, characterized by the following features.

12. A sewer maintenance and management method according to claim 9, Furthermore, the process includes a water level gauge installation step, which involves installing a water level gauge to measure whether the water level in the sewage facility exceeds a predetermined standard water level, The system also includes a reset step to reset the sum if the water level indicated by the water level gauge exceeds a predetermined reference water level. A method for maintaining and managing sewer systems, characterized by the following features.

13. A sewer maintenance method for maintaining a sewer facility having a concrete surface, A pH sensor installation step involves attaching a pH sensor, which detects the pH value, to the gas phase portion of the concrete surface. A pH value acquisition step in which the pH value of the concrete surface is detected by the pH sensor, A liquid properties determination step in which a liquid properties determination device outputs a predetermined alarm when it meets predetermined conditions indicating that the pH value is in an acidic state, It has, The pH value acquisition step and the liquid properties determination step are repeated, Furthermore, the process includes a water level gauge installation step, which involves installing a water level gauge to measure whether the water level in the sewage facility exceeds a predetermined standard water level, A sprinkler system installation step involves installing a sprinkler system having a sprinkler function at a sewer facility upstream of the aforementioned sewer facility, When the liquid properties determination device outputs an alarm, the watering device starts watering in a watering step, The system also includes an alarm deactivation step that stops the water spraying if the water level indicated by the water level gauge exceeds a predetermined standard water level. A method for maintaining and managing sewer systems, characterized by the following features.

14. A sewer maintenance method for maintaining a sewer facility having a concrete surface, A pH sensor installation step involves attaching a pH sensor, which detects the pH value, to the gas phase portion of the concrete surface. A pH value acquisition step in which the pH value of the concrete surface is detected by the pH sensor, A liquid properties determination step in which a liquid properties determination device outputs a predetermined alarm when it meets predetermined conditions indicating that the pH value is in an acidic state, It has, The pH value acquisition step and the liquid properties determination step are repeated, The pH sensor includes a pH measuring electrode and a reference electrode. The pH measuring electrode has an oxidized tungsten wire tip, and the unoxidized portion is insulated. The aforementioned reference electrode is a silver-silver chloride electrode filled with an aqueous potassium chloride solution as the internal solution. In the pH sensor installation step, A hole is made in the concrete surface in a diagonal downward direction. After pouring tap water into the hole, insert the reference electrode so that it is in contact with a part of the hole. The tip portion of the pH measuring electrode is installed so as to contact the concrete surface. A method for maintaining and managing sewer systems, characterized by the following features.

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