System for detecting abnormality in treatment of waste water, and method and program executed in that system

Abstract

To provide a system for detecting an abnormality in treatment of wastewater.SOLUTION: A system according to the present invention comprises: means for identifying the pH value in wastewater multiple times over time; means for determining, on the basis of a transition in the plurality of pH values identified in the wastewater, whether an abnormality has occurred in a reaction in which ammonium ions in the wastewater change to nitrite ions; and means for, when it is determined that an abnormality has occurred in the reaction, presenting a warning indicating that an abnormality has occurred in the reaction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a system for detecting an abnormality in wastewater treatment, and a method and a program executed in the system. [Background technology]

[0002] 2. Description of the Related Art Wastewater treatment using a nitrification-denitrification reaction has been known for some time (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-022865 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a method for determining whether an abnormality has occurred in the nitrification / denitrification reaction based on the sludge concentration distribution of wastewater, the pH value, etc. However, a device for measuring the sludge concentration distribution of wastewater requires extra cost and installation space.

[0005] An object of the present invention is to provide a system that makes it possible to detect an abnormality in wastewater treatment based solely on the pH value in the wastewater, and a method and program executed in the system. [Means for solving the problem]

[0006] In one aspect of the present invention, the system of the present invention is a system for detecting abnormalities in wastewater treatment, and the system includes: means for identifying a pH value in the wastewater multiple times over time; means for determining whether or not an abnormality has occurred in a reaction in which ammonium ions in the wastewater are converted to nitrite ions based on changes in the identified multiple pH values ​​in the wastewater; and means for issuing a warning to the effect that an abnormality has occurred in the reaction when it is determined that an abnormality has occurred in the reaction.

[0007] In one embodiment of the present invention, the means for determining whether or not an abnormality has occurred in the reaction may include a means for determining whether or not a change in the identified plurality of pH values ​​in the wastewater indicates a predetermined change, and a means for determining that an abnormality has occurred in the reaction when the change in the identified plurality of pH values ​​in the wastewater indicates the predetermined change.

[0008] In one embodiment of the present invention, the means for determining whether or not a transition of the identified multiple pH values ​​in the wastewater shows the predetermined transition may include a means for identifying a pH value for each predetermined time from the transition of the identified multiple pH values ​​in the wastewater; a means for identifying an arithmetic mean value for each predetermined time corresponding to the pH value for each predetermined time by calculating, for each pH value, an arithmetic mean value of the pH value and other pH values ​​in the vicinity of the pH value; a means for converting the arithmetic mean value for each predetermined time from a discrete value to a continuous value and generating a continuous function of the arithmetic mean values ​​for the predetermined time; a means for determining whether or not a local minimum exists in the continuous function of the arithmetic mean values ​​for the predetermined time; and a means for determining that a transition of the identified multiple pH values ​​in the wastewater shows the predetermined transition if a local minimum exists in the continuous function of the arithmetic mean values ​​for the predetermined time.

[0009] In one embodiment of the present invention, the means for determining whether or not a local minimum exists in the continuous function of the arithmetic mean value for each predetermined time may include means for differentiating the continuous function of the arithmetic mean value for each predetermined time, means for applying a root-finding algorithm to the derivative of the continuous function of the arithmetic mean value for each predetermined time to determine whether or not a solution exists, and means for determining that a local minimum exists in the continuous function of the arithmetic mean value for each predetermined time if the solution exists.

[0010] In one embodiment of the present invention, the arithmetic mean value for each predetermined time is the arithmetic mean value from time tN to time t, where N is a positive value less than t, and the system may further include a means for identifying a pH value at a time s prior to time tN when the solution does not exist, and calculating the arithmetic mean value of the pH value at time s and other pH values ​​in the vicinity of the pH value at time s, thereby identifying the arithmetic mean value at time s, a means for calculating ΔX as (the arithmetic mean value at time t)-(the arithmetic mean value at time s), and a means for determining whether or not ΔX is a positive value, and when it is determined that ΔX is not a positive value, it may be determined that no abnormality has occurred in the reaction.

[0011] In one embodiment of the present invention, the system may further include a means for determining whether or not a transition of the arithmetic mean value from time s to time t is on an upward trend when it is determined that the ΔX is a positive value, by calculating an arithmetic mean value corresponding to the pH value at each predetermined time from time s to time tN and calculating a difference between the arithmetic mean value at time t and the arithmetic mean value corresponding to the pH value at each predetermined time from time s to time tN, and the means for determining whether or not an abnormality has occurred in the reaction may determine that an abnormality has occurred in the reaction when it is determined that a transition of the arithmetic mean value from time tN to time t is on an upward trend.

[0012] In one embodiment of the present invention, the means for determining the pH value in the wastewater may include means for measuring at least one of the pH value, the ammonium ion concentration, and the nitrite ion concentration in the wastewater.

[0013] In one aspect of the present invention, the method of the present invention is a method executed in a system for detecting abnormalities in wastewater treatment, the system including a processor unit, and the method including the processor unit identifying a pH value in the wastewater multiple times over time, the processor unit determining whether or not an abnormality has occurred in a reaction in which ammonium ions in the wastewater are converted to nitrite ions based on changes in the identified multiple pH values ​​in the wastewater, and if the processor unit determines that an abnormality has occurred in the reaction, presenting a warning to the effect that an abnormality has occurred in the reaction.

[0014] In one aspect of the present invention, the program of the present invention is a program executed in a system for detecting abnormalities in wastewater treatment, the system having a processor unit, and when the program is executed by the processor unit, it causes the processor unit to at least perform the following: identifying the pH value in the wastewater multiple times over time; determining whether or not an abnormality has occurred in the reaction in which ammonium ions in the wastewater are converted to nitrite ions based on the changes in the identified multiple pH values ​​in the wastewater; and if it is determined that an abnormality has occurred in the reaction, presenting a warning to the effect that an abnormality has occurred in the reaction. Effect of the Invention

[0015] According to the present invention, it is possible to provide a system that enables detection of anomalies in wastewater treatment based solely on the pH value in the wastewater, and a method and program executed in the system. [Brief description of the drawings]

[0016] [Figure 1] Schematic diagram of the mechanism related to the nitrification / denitrification reaction in continuous wastewater treatment [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of a system 200 that enables detection of an abnormality in wastewater treatment based only on the pH value in the wastewater. [Diagram 3] FIG. 2 is a diagram illustrating an example of a process executed in a computer system 210. [Figure 4] FIG. 4 is a diagram showing an example of processing in step S302 in FIG. 3; [Diagram 5] FIG. 5 is a diagram showing an example of processing in step S404 in FIG. 4; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] 1. Wastewater treatment system using nitrification / denitrification Generally, there are continuous wastewater treatment systems in which wastewater treatment is carried out using a plurality of connected tanks, and batchwise wastewater treatment systems in which wastewater treatment is carried out using a single tank.

[0019] FIG. 1 is a schematic diagram of the mechanism of the portion of continuous wastewater treatment relating to the nitrification / denitrification reaction.

[0020] The wastewater is treated by a nitrification / denitrification reaction while passing through the first tank 110 and the second tank 120. The first tank 110 is equipped with an aeration device 130 and a first activated sludge 140. In the first tank 110, a so-called nitrification reaction takes place. The nitrification reaction is a reaction in which ammonium ions in the wastewater are converted into nitrite ions (2NH4 + +O2→2NO2 - +2H2O+4H + ) and the reaction in which nitrite ions change to nitrate ions (2NO2 - +O2→2NO3 - The first activated sludge 140 contains nitrifying bacteria for promoting the nitrification reaction. The nitrite ions and nitrate ions produced after the nitrification reaction in the first tank 110 are flowed into the second tank 120.

[0021] The second tank 120 contains the second activated sludge 150. In the second tank 120, a so-called denitrification reaction takes place. The denitrification reaction is a reaction in which nitrite ions are converted to nitrogen (2NO2 -+3H2→N2+2OH - +2H2O) and the reaction in which the nitrate ion changes to nitrogen (2NO3 - +5H2→N2+2OH - +4H2O). The second activated sludge 150 contains denitrifying bacteria for promoting the denitrification reaction. The treated water generated after the denitrification reaction in the second tank 120 is discharged from the second tank 120.

[0022] In the embodiment shown in FIG. 1, the reaction in which ammonium ions in the wastewater are converted to nitrite ions (2NH4 + +O2→2NO2 - +2H2O+4H + ) and the reaction in which nitrite ions change to nitrate ions (2NO2 - +O2→2NO3 - ) occurs in the same tank, but the present invention is not limited to this. For example, the reaction (2NH4 + +O2→2NO2 - +2H2O+4H + ) and the reaction in which nitrite ions change to nitrate ions (2NO2 - +O2→2NO3 - ) may be generated in separate interconnected vessels.

[0023] 2. Configuration of a system that enables detection of abnormalities in wastewater treatment based solely on the pH value of the wastewater The applicant focused on the nitrification reaction among nitrification and denitrification reactions in order to make it possible to detect abnormalities in the nitrification and denitrification reaction in the wastewater treatment based only on the pH value in the wastewater. When the reaction in which ammonium ions are converted to nitrite ions is progressing, the pH value in the wastewater decreases. Therefore, the applicant thought that by detecting that the pH value in the wastewater is not decreasing, it would be possible to know that the reaction in which ammonium ions are converted to nitrite ions is not progressing normally, and to determine that an abnormality has occurred in the treatment of the wastewater.

[0024] The applicant focused particularly on the tank in which the reaction of converting ammonium ions into nitrite ions takes place in continuous wastewater treatment, and believed that by monitoring the changes in the pH value of the wastewater in that tank, it would be entirely possible to detect abnormalities in the wastewater treatment process based solely on the pH value of the wastewater.

[0025] FIG. 2 shows an example of the configuration of a system 200 that makes it possible to detect an abnormality in the treatment of wastewater based solely on the pH value in the wastewater.

[0026] In the embodiment shown in FIG. 2, the system 200 includes a computer system 210 for detecting anomalies in the treatment of wastewater and devices 2201-220 for identifying a pH value in the wastewater. M The computer system 210 includes devices 2201 to 220 via the Internet 230. M Here, M is an integer equal to or greater than 1.

[0027] The computer system 210 is an information processing system that executes processing for a management company that manages information related to wastewater treatment. In the embodiment shown in Fig. 2, the computer system 210 includes an interface unit 211, a processor unit 212 including one or more CPUs (Central Processing Units), and a memory unit 213. The hardware configuration of the computer system 210 is not particularly limited as long as it can realize its functions, and may be configured as a single machine or a combination of multiple machines.

[0028] The interface unit 211 includes devices 2201 to 220 M Controls communication with each of the following:

[0029] The memory unit 213 stores programs required to execute processing, data required to execute the programs, and the like. Here, there is no limit to how the programs are stored in the memory unit 213. For example, the programs may be pre-installed in the memory unit 213. Alternatively, the programs may be installed in the memory unit 213 by being downloaded via a network such as the Internet 230, or may be installed in the memory unit 213 via a storage medium such as an optical disk or a USB.

[0030] The processor unit 212 controls the overall operation of the computer system 210. The processor unit 212 reads out a program stored in the memory unit 213 and executes the program. This allows the computer system 210 to function as a device that executes desired steps, and the processor unit 212 of the computer system 210 to operate as a means for achieving a desired function.

[0031] 2, the computer system 210 is connected to a database unit 240. The database unit 240 stores information indicating a splev function for B-spline interpolation, information indicating a root-finding algorithm, information indicating a kpss function, and the like, but is not limited to these.

[0032] The device 2201 is installed in a tank (for example, the first tank 110 shown in FIG. 1) in which a reaction occurs in which ammonium ions are converted into nitrite ions. The device 2201 is configured to be capable of measuring a predetermined parameter in the wastewater in order to identify the pH value in the wastewater. The predetermined parameter in the wastewater may be the pH value in the wastewater, or the ammonium ion concentration in the wastewater, or the nitrite ion concentration in the wastewater. The device 2201 may be installed inside the tank in which a reaction occurs in which ammonium ions are converted into nitrite ions, or may be installed outside the tank in which a reaction occurs in which ammonium ions are converted into nitrite ions, as long as it is possible to measure the predetermined parameter in the wastewater. M The same is true for each of the above.

[0033] In the embodiment shown in FIG. M are described as being capable of communicating with computer system 210 via Internet 230, the invention is not so limited. Any type of network may be used in place of Internet 230.

[0034] In the embodiment shown in FIG. 2, the database unit 240 is provided outside the computer system 210, but the present invention is not limited to this. The database unit 240 can also be provided inside the computer system 210. The configuration of the database unit 240 is not limited to a specific hardware configuration. For example, the database unit 240 may be configured as a single hardware component, or may be configured as multiple hardware components. For example, the database unit 240 may be configured as a single external hard disk device of the computer system 210, or may be configured as a cloud storage connected via a network.

[0035] 3. Processing performed in a computer system Fig. 3 shows an example of processing executed in the computer system 210. Each step shown in Fig. 3 is executed, for example, by the processor unit 211 of the computer system 210. Each step shown in Fig. 3 will be described below.

[0036] Step S301: A pH value in the wastewater is determined multiple times over time. The pH value in the wastewater is determined based on a predetermined parameter in the wastewater measured by the device 2201.

[0037] For example, when the device 2201 measures a pH value, the computer system 210 can identify the pH value in the wastewater by receiving from the device 2201 the pH value measured by the device 2201. For example, when the device 2201 measures an ammonium ion concentration in the wastewater, the computer system 210 can identify the pH value in the wastewater by receiving from the device 2201 the ammonium ion concentration in the wastewater measured by the device 2201 and calculating the pH value in the wastewater based on the ammonium ion concentration in the wastewater received from the device 2201. For example, when the device 2201 measures a nitrite ion concentration in the wastewater, the computer system 210 can identify the pH value in the wastewater by receiving from the device 2201 the nitrite ion concentration in the wastewater measured by the device 2201 and calculating the pH value in the wastewater based on the nitrite ion concentration in the wastewater received from the device 2201.

[0038] The pH value in the wastewater is determined, for example, for each predetermined period (for example, every 30 minutes, every hour, every 3 hours, every 6 hours, every 12 hours, every 24 hours). The pH value in the wastewater may be determined based on the predetermined parameter in the wastewater each time the computer system 210 receives the predetermined parameter in the wastewater from the device 2201 for each predetermined period (i.e., for each predetermined period). Alternatively, the pH value in the wastewater may be determined based on the predetermined parameter in the wastewater by the computer system 210 receiving the predetermined parameter in the wastewater from the device 2201 multiple times within a predetermined period and extracting the predetermined parameter for each predetermined period from the multiple predetermined parameters in the wastewater received within the predetermined period.

[0039] Step S302: It is determined whether or not an abnormality has occurred in the reaction in which ammonium ions in the wastewater change to nitrite ions. This process is performed based on the transition of the pH value in the wastewater identified in step S301. If the determination result is "Yes", the process proceeds to step S303, and if the determination result is "No", the process proceeds to step S304. An example of this process will be described in detail with reference to FIG. 4.

[0040] For example, the computer system 210 (particularly, the processor unit 211 of the computer system 210) determines whether the change in the pH value in the wastewater identified in step S301 shows a predetermined change, and if it is determined that the change in the pH value in the wastewater identified in step S301 shows a predetermined change, it can be determined that an abnormality has occurred in the reaction in which ammonium ions in the wastewater are converted into nitrite ions, and if it is determined that the change in the pH value in the wastewater identified in step S301 does not show a predetermined change, it can be determined that no abnormality has occurred in the reaction in which ammonium ions in the water are converted into nitrite ions.

[0041] The predetermined transition may include, but is not limited to, for example, the pH value in the wastewater increasing locally over time, the pH value in the wastewater increasing globally over time, the pH value in the wastewater transitioning to have a local minimum, etc.

[0042] Step S303: A warning is issued to the effect that an abnormality has occurred in the reaction in which ammonium ions in the wastewater are converted into nitrite ions. This warning may be issued to the user of the computer system 210 via the display of the computer system 210, for example, by the computer system 210 displaying the warning on the display of the computer system 210, or may be issued to the user of the computer system 210 by the computer system 210 transmitting the warning to a user device owned by the user of the computer system 210.

[0043] Step S304: The pH value in the wastewater is determined at least once. This process is similar to step S301 in FIG. 3, so the detailed description thereof is omitted here.

[0044] Fig. 4 shows an example of the process in step S302 in Fig. 3. Each step shown in Fig. 4 is executed, for example, by the processor unit 211 of the computer system 210. Each step shown in Fig. 4 will be described below.

[0045] Step S401: A pH value for each predetermined time is identified from the multiple pH values ​​in the wastewater identified in step S301. This process is achieved by extracting and / or selecting a pH value for each predetermined time from the multiple pH values ​​in the wastewater identified in step S301.

[0046] Step S402: For each pH value at each predetermined time specified in step S401, the arithmetic mean value between the pH value and other pH values ​​nearby the pH value is calculated. This allows the arithmetic mean value at each predetermined time corresponding to each pH value at each predetermined time specified in step S401 to be specified. In this specification, the "other pH values ​​nearby" of the pH value refers to other pH values ​​specified within a predetermined time range from the pH value. The predetermined time range is determined in advance depending on the size and structure of the tank. For convenience, the arithmetic mean value at each predetermined time specified in step S402 is specified from "time tN to time t". N is a positive value less than t.

[0047] For example, as shown in Table 1, suppose that the pH value for each hour is specified in step S401. Also, within 2 hours is defined as "nearby". In this case, for example, the "arithmetic mean value at 2 o'clock" corresponding to the "pH value at 2 o'clock" is the arithmetic mean value 6.994=(7.00+6.98+6.99+6.98+7.02) / 5 of the "pH value at 0 o'clock", the "pH value at 1 o'clock", the "pH value at 2 o'clock", the "pH value at 3 o'clock", and the "pH value at 4 o'clock". For example, the "arithmetic mean value at 2 o'clock" corresponding to the "pH value at 3 o'clock" is the arithmetic mean value (6.98+6.99+6.98+7.02+7.04) / 5=7.002 of the "pH value at 1 o'clock", the "pH value at 2 o'clock", the "pH value at 3 o'clock", the "pH value at 5 o'clock", and the "pH value at 6 o'clock". In this way, the arithmetic mean value for each predetermined time corresponding to each of the pH values ​​for each predetermined time is specified. As shown in Table 1, these arithmetic mean values ​​for each given time are discrete values. [Table 1]

[0048] In this way, by taking the arithmetic mean value for each pH value at each specified time, the effect of the inflow of new wastewater on the fluctuations in the pH value can be reduced, and the effect of fluctuations in the number of bacteria in the first activated sludge 140, where the reaction of converting ammonium ions to nitrite ions is occurring, on the fluctuations in the pH value can be increased.

[0049] Step S403: The arithmetic mean values ​​for each predetermined time period identified in step S402 are converted from discrete values ​​to continuous values, thereby generating a continuous function of the arithmetic mean values ​​for each predetermined time period. The conversion of the arithmetic mean values ​​for each predetermined time period identified in step S402 from discrete values ​​to continuous values ​​is for the purpose of interpolating between the arithmetic mean values ​​(discrete values) for each predetermined time period. This conversion can be achieved, for example, by applying a splev function to each of the arithmetic mean values ​​for each predetermined time period identified in step S402 to perform B-spline interpolation. This process can be performed by referring to the database unit 240 that stores information indicating the splev function.

[0050] Step S404: It is determined whether or not there is a minimum of the continuous function of the arithmetic mean value for each predetermined time generated in step S403. If the result of the determination is "Yes", the process proceeds to step S405, and if the result of the determination is "No", the process proceeds to step S406. An example of this process will be described in detail with reference to FIG. 5.

[0051] Step S405: It is determined that the trend in the pH value in the wastewater identified in step S301 shows a predetermined trend (i.e., the pH value in the wastewater is trending so as to have a minimum), and according to the determination result "No" in step S302, it is determined that an abnormality has occurred in the reaction in which ammonium ions in the wastewater are converted into nitrite ions.

[0052] Step S406: It is determined that the change in the pH value in the wastewater identified in step S301 does not show a predetermined change, and according to the determination result "Yes" in step S302, it is determined that no abnormality has occurred in the reaction in which ammonium ions in the wastewater are converted into nitrite ions.

[0053] In the embodiment shown in FIG. 4, an example of using the splev function to generate a continuous function of the arithmetic mean value for each predetermined time has been described, but the present invention is not limited to this. Other python functions may be used to generate a continuous function of the arithmetic mean value for each predetermined time. For example, interp1d, Akima1DInterpolator, splprep, etc. may be used to generate a continuous function of the arithmetic mean value for each predetermined time.

[0054] Fig. 5 shows an example of the process in step S404 in Fig. 4. Each step shown in Fig. 5 is executed, for example, by the processor unit 211 of the computer system 210. Each step shown in Fig. 5 will be described below.

[0055] Step S501: The continuous function of the arithmetic mean value for each predetermined time generated in step S403 is differentiated, thereby generating a derivative of the continuous function of the arithmetic mean value for each predetermined time.

[0056] Step S502: A root-finding algorithm is applied to the derivative of the continuous function of the arithmetic mean value for each predetermined time generated in step S501. This process is performed by referring to the database unit 240 that stores the root-finding algorithm.

[0057] Step S503: As a result of applying a root finding algorithm to the derivative of the continuous function of the arithmetic mean values ​​for each predetermined time generated in step S501 in step S502, it is determined whether or not a solution exists in the derivative of the continuous function of the arithmetic mean values ​​for each predetermined time generated in step S501. If the determination result is "Yes", it is determined that a local minimum exists in the continuous function of the arithmetic mean values ​​for each predetermined time generated in step S403, so the process proceeds to step S405 in Fig. 4, where it is determined that an abnormality has occurred in the reaction in which ammonium ions in the wastewater change to nitrite ions, and if the determination result is "No", the process proceeds to step S504.

[0058] Step S504: Similar to step S401 in FIG. 4, identify the pH value at time s before time t - N. Similar to step S402 in FIG. 4, calculate the weighted average value of the pH value at time s and other pH values in the vicinity of the pH value at time s. Thereby, the weighted average value at time s is identified. Note that s is a positive value satisfying s < t - N.

[0059] Step S505: Calculate the difference ΔX between the weighted average value at time t and the weighted average value at time s. That is, (weighted average value at time t) - (weighted average value at time s) is calculated as ΔX.

[0060] Step S506: Determine whether ΔX calculated in step S505 is a positive value. If the determination result is "Yes", since there is a possibility that the pH value in the drainage water is rising, the process proceeds to step S507. If the determination result is "No", since the pH value in the drainage water has not risen, the process proceeds to step S406 in FIG. 4, and it is determined that there is no abnormality in the reaction in which ammonium ions in the drainage water change to nitrite ions.

[0061] Step S507: Calculate the weighted average value corresponding to the pH value at each predetermined time from time s to time t - N, and calculate the difference between the weighted average value at time t and the weighted average value corresponding to the pH value at each predetermined time from time s to time t - N. Thereby, it is possible to plot the trend of the transition of the weighted average value from time s to time t, which is a wider range than from time t - N to time t. This process is achieved, for example, by setting up a null hypothesis that the transition of the weighted average value from time s to time t is a stationary process (i.e., there is no upward trend) with respect to the weighted average value from time s to time t and performing a KPSS test using the kpss function. This process can be executed by referring to the database unit 240 that stores the kpss function.

[0062] Step S508: It is determined whether the transition of the arithmetic mean value from time s to time t is on an upward trend. If the determination result is "Yes", it is determined that the pH value in the wastewater is rising over a wide time span, and the process proceeds to step S405 in FIG. 4, where it is determined that an abnormality has occurred in the reaction in which ammonium ions in the wastewater are converted to nitrite ions. If the determination result is "No", the process proceeds to step S406 in FIG. 4, where it is determined that no abnormality has occurred in the reaction in which ammonium ions in the wastewater are converted to nitrite ions. For example, if the null hypothesis is rejected at a specific significance level as a result of executing the KPSS test, it is determined that the transition of the arithmetic mean value from time s to time t is on an upward trend.

[0063] In the embodiment shown in FIG. 5, an example of using the splev function to measure the trend of the arithmetic mean value from time s to time t has been described, but the present invention is not limited to this. Other tests may be used to measure the trend of the arithmetic mean value from time s to time t. For example, an ADF test calculated using the adfuller function may be used to measure the trend of the arithmetic mean value from time s to time t.

[0064] 5, an example has been described in which the process proceeds to step S504 if the determination result in step S503 is "No," but the present invention is not limited to this. For example, if the determination result in step S503 is "No," it is highly likely that the pH value in the wastewater that continues to fall has not started to rise, so the computer system 210 determines that there is no minimum in the continuous function of the arithmetic mean value for each predetermined time generated in step S403, and therefore determines that no abnormality has occurred in the reaction in which ammonium ions in the wastewater change to nitrite ions, and steps S504 to S508 may be omitted.

[0065] 5, an example has been described in which the process proceeds to step S507 if the determination result in step S506 is "No," but the present invention is not limited to this. For example, if the determination result in step S506 is "Yes," the computer system 210 determines that the pH value in the wastewater is rising at a local time (i.e., from time s to time t), and therefore determines that an abnormality is occurring in the reaction that converts ammonium ions in the wastewater into nitrite ions, and step S508 may be omitted.

[0066] As described above, the present invention has been illustrated using the preferred embodiment of the present invention, but the present invention should not be interpreted as being limited to this embodiment. It is understood that the scope of the present invention should be interpreted only by the claims. It is understood that a person skilled in the art can implement an equivalent scope based on the description of the present invention and technical common sense from the description of the specific preferred embodiment of the present invention. [Industrial Applicability]

[0067] INDUSTRIAL APPLICABILITY The present invention is useful for providing a system that makes it possible to detect an abnormality in wastewater treatment based solely on the pH value of the wastewater, as well as a method and program executed in the system. [Explanation of symbols]

[0068] 200 Systems 210 Computer Systems 2201~220 M Device 240 Database Department

Claims

1. A system for detecting anomalies in wastewater treatment, the system comprising: A means for determining a pH value in the wastewater multiple times over time; a means for determining whether or not an abnormality has occurred in a reaction in which ammonium ions in the wastewater are converted into nitrite ions, based on transitions of the specified plurality of pH values ​​in the wastewater; a means for presenting a warning that an abnormality has occurred in the reaction when it is determined that an abnormality has occurred in the reaction; A system comprising:

2. The means for determining whether or not an abnormality has occurred in the reaction includes: A means for determining whether or not the transition of the identified plurality of pH values ​​in the wastewater shows a predetermined transition; a means for determining that an abnormality has occurred in the reaction when the transition of the specified plurality of pH values ​​in the wastewater shows the predetermined transition; The system of claim 1 , comprising:

3. The means for determining whether or not the transition of the identified plurality of pH values ​​in the wastewater shows the predetermined transition is A means for identifying a pH value for each predetermined time from the transition of the identified plurality of pH values ​​in the wastewater; a means for calculating an arithmetic mean value of each pH value and other pH values ​​in the vicinity of the pH value, thereby specifying an arithmetic mean value for each of the predetermined time periods corresponding to the pH value for each of the predetermined time periods; means for converting the arithmetic mean value for each predetermined time from a discrete value to a continuous value and generating a continuous function of the arithmetic mean value for each predetermined time; means for determining whether or not a minimum exists in the continuous function of the arithmetic mean value for each predetermined time; means for determining that a transition of the identified plurality of pH values ​​in the wastewater shows the predetermined transition when a local minimum exists in the continuous function of the arithmetic mean value for each predetermined time; The system of claim 2 , comprising:

4. The means for determining whether or not a minimum exists in the continuous function of the arithmetic mean value for each predetermined time period includes: means for differentiating a continuous function of the arithmetic mean value for each predetermined time; means for applying a root-finding algorithm to the derivative of the continuous function of the arithmetic mean value for each predetermined time period to determine whether a solution exists; means for determining, if the solution exists, that a minimum exists in the continuous function of the arithmetic mean value for each predetermined time; The system of claim 3 , comprising:

5. The arithmetic mean value for each predetermined time period is an arithmetic mean value from time t-N to time t, where N is a positive value less than t, The system comprises: means for determining an arithmetic mean value of a time s prior to time t-N when the solution does not exist, by determining a pH value at the time s and calculating an arithmetic mean value of the pH value at the time s and other pH values ​​in the vicinity of the pH value at the time s; A means for calculating ΔX by subtracting the arithmetic mean value at time t from the arithmetic mean value at time s; A means for determining whether or not the ΔX is a positive value; Further equipped with The system according to claim 4 , wherein if it is determined that the ΔX is not a positive value, it is determined that no abnormality has occurred in the reaction.

6. The system comprises: When it is determined that the ΔX is a positive value, a means for determining whether or not the transition of the arithmetic mean value from time s to time t is on an upward trend by calculating an arithmetic mean value corresponding to the pH value at each predetermined time from time s to time t-N and calculating a difference between the arithmetic mean value at time t and the arithmetic mean value corresponding to the pH value at each predetermined time from time s to time t-N. Further equipped with The system according to claim 5, wherein the means for determining whether or not an abnormality has occurred in the reaction determines that an abnormality has occurred in the reaction when it is determined that the trend in the arithmetic mean value from time t-N to time t is on an upward trend.

7. The system of claim 1 , wherein the means for determining a pH value in the wastewater includes means for measuring at least one of a pH value, an ammonium ion concentration, and a nitrite ion concentration in the wastewater.

8. A method to be performed in a system for detecting an abnormality in wastewater treatment, the system comprising: The method comprises: The processor unit determines a pH value in the wastewater a plurality of times over time; The processor unit determines whether or not an abnormality occurs in a reaction in which ammonium ions in the wastewater are converted into nitrite ions, based on transitions of the specified plurality of pH values ​​in the wastewater; When it is determined that an abnormality has occurred in the reaction, the processor unit presents a warning that an abnormality has occurred in the reaction. A method comprising:

9. A program executed in a system for detecting an abnormality in wastewater treatment, the system comprising: a processor unit; When the program is executed by the processor unit, Determining a pH value in the wastewater multiple times over time; determining whether or not an abnormality has occurred in a reaction in which ammonium ions in the wastewater are converted into nitrite ions based on transitions of the specified plurality of pH values ​​in the wastewater; When it is determined that an abnormality has occurred in the reaction, a warning is presented to the effect that an abnormality has occurred in the reaction. A program that causes the processor unit to execute at least the steps of:

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