WATER TREATMENT PLANT CONTROLLING METHOD AND CONTROLLING PROGRAM, AND WATER TREATMENT SYSTEM

• US 20160362305A1
• Filed: 11/25/2013
• Published: 12/15/2016
• Est. Priority Date: 11/25/2013
• Status: Active Grant

• Current Assignee: Kurita Water Industries Limited
• Original Assignee: Kurita Water Industries Limited
• Inventors: OHTSUKI, Takayuki, SASAKI, Yuuya, IIZUKA, Hiroshi, NAKANO, Yoshimasa
• Granted Patent: US 10,597,308 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 2311/04 Specific process operations in the feed stream; Feed pretreatment
• CPC Class Codes: B01D 2311/103 Heating
• CPC Class Codes: B01D 2311/243 Electrical conductivity control
• CPC Class Codes: B01D 61/025 Reverse osmosis; Hyperfiltration
• CPC Class Codes: B01D 61/04 Feed pretreatment
• CPC Class Codes: B01D 61/12 Controlling or regulating
• CPC Class Codes: C02F 1/008 Control or steering systems not provided for elsewhere in subclass C02F
• CPC Class Codes: C02F 1/441 by reverse osmosis
• CPC Class Codes: C02F 2209/001 Upstream control, i.e. monitoring for predictive control
• CPC Class Codes: C02F 2209/003 Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process
• CPC Class Codes: C02F 2209/006 comprising a software program or a logic diagram
• CPC Class Codes: C02F 2209/02 Temperature
• CPC Class Codes: C02F 2209/04 Oxidation reduction potential [ORP]
• CPC Class Codes: C02F 2209/05 Conductivity or salinity
• CPC Class Codes: C02F 2209/08 Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD]
• CPC Class Codes: C02F 2209/16 Total nitrogen (tkN-N)
• CPC Class Codes: C02F 2209/20 Total organic carbon [TOC]
• CPC Class Codes: C02F 2209/30 H2
• CPC Class Codes: C02F 2209/40 Liquid flow rate
• CPC Class Codes: C02F 2303/22 Eliminating or preventing deposits, scale removal, scale prevention C02F1/042, C02F1/4602, C02F5/00 take precedence
• CPC Class Codes: G05B 13/0205 : not using a model or a simulator of the controlled system

Abstract

A water treatment plant controlling method including: determining whether or not there is a correlation, in water to be treated, between a water quality index and a concentration of a pollution component having no causal relationship with the water quality index, from a result of sample analysis of the water to be treated performed periodically; and (a) under a condition that there is a correlation, statistically analyzing a distribution of measurement values of the water quality index in a previous certain period of the water to be treated, and based on a result of the statistical analysis and the correlation, estimating the concentration of the pollution component of the water to be treated; and determining an operating condition of a water treatment plant for treating the water to be treated, based on the estimated concentration of the pollution component of the water to be treated; or (b) on a condition that a correlation is absent, statistically analyzing a distribution of concentration of the pollution component in all past sample analyses of the water to be treated, and based on a result of the statistical analysis, estimating the concentration of the pollution component of the water to be treated.

Claims

1. A water treatment plant controlling method comprising:

a correlation determination step of determining whether or not there is a correlation, in water to be treated, between a water quality index and a concentration of a pollution component having no causal relationship with the water quality index, from a result of sample analysis of the water to be treated performed periodically;

a first pollution component concentration estimation step of, on a condition that there is the correlation, statistically analyzing a distribution of measurement values of the water quality index in a previous certain period of the water to be treated, and based on a result of the statistical analysis and the correlation, estimating the concentration of the pollution component of the water to be treated;

a second pollution component concentration estimation step of, on a condition that the correlation is absent, statistically analyzing a distribution of concentration of the pollution component in past sample analyses of the water to be treated, and based on a result of the statistical analysis, estimating the concentration of the pollution component of the water to be treated; and

selecting one of the first pollution component concentration estimation step and the second pollution component concentration estimation step based on a determination of the correlation determination step, and determining an operating condition of a water treatment plant for treating the water to be treated based on the concentration of the pollution component of the water to be treated estimated by the selected estimation step.

2. The water treatment plant controlling method according to claim 1, wherein there is the correlation and wherein the first pollution component concentration estimation step comprises steps of:

calculating a regression line and a prediction limit thereof by performing a regression analysis on the result of the sample analysis of the water to be treated;

calculating, by the statistical analysis, an average value and a standard deviation of the distribution of the measurement values of the water quality index in the previous certain period of the water to be treated;

obtaining a maximum value of the measurement values of the water quality index falling under an appearance probability set based on the average value and the standard deviation; and

estimating the concentration of the pollution component of the water to be treated based on the prediction limit of the regression line and the maximum value of the measurement values of the water quality index.

4. The water treatment plant controlling method according to claim 1, wherein the correlation is absent and wherein the second pollution component concentration estimation step includes steps of:

calculating, by a statistical analysis, an average value and a standard deviation of the distribution of the concentration of the pollution component in all past sample analyses of the water to be treated, obtaining a maximum value of the concentration of the pollution component falling under an appearance probability set based on the average value and the standard deviation, and

estimating the concentration of the pollution component of the water to be treated to be the maximum value of the concentration.

5. The water treatment plant controlling method according to claim 1, wherein the water quality index is conductivity of the water to be treated.

6. The water treatment plant controlling method according to claim 1, wherein the water quality index is turbidity of the water to be treated.

7. The water treatment plant controlling method according to claim 1, wherein the water quality index is absorbance of the water to be treated.

8. The water treatment plant controlling method according to claim 1, wherein the water quality index is potential Hydrogen of the water to be treated.

9. The water treatment plant controlling method according to claim 1, wherein the water quality index is oxidation-reduction potential of the water to be treated.

3. (canceled)

10. A non-transitory computer-readable storage medium storing a water treatment plant controlling program for causing a computer to execute a process, comprising:

a correlation determination procedure of determining whether or not there is a correlation, in water to be treated, between a water quality index and a concentration of a pollution component having no causal relationship with the water quality index, from a result of sample analysis of the water to be treated performed periodically;

a first pollution component concentration estimation procedure of, on a condition that there is the correlation, statistically analyzing a distribution of measurement values of the water quality index in a previous certain period of the water to be treated, and based on a result of the statistical analysis and the correlation, estimating the concentration of the pollution component of the water to be treated;

a second pollution component concentration estimation procedure of, on a condition that the correlation is absent, statistically analyzing a distribution of concentration of the pollution component in past sample analyses of the water to be treated, and based on a result of the statistical analysis, estimating the concentration of the pollution component of the water to be treated; and

selecting one of the first pollution component concentration estimation procedure and the second pollution component concentration estimation procedure based on a determination of the correlation determination procedure, and determining an operating condition of the water treatment plant for treating the water to be treated based on the concentration of the pollution component of the water to be treated estimated by the selected estimation procedure.

11. (canceled)

12. A water treatment system comprising:

a water treatment plant;

a measurement device for measuring a water quality index of water to be treated in the water treatment plant; and

a controller that controls the water treatment plant, wherein

the controller includes;

a correlation determiner configured to determine whether or not there is the correlation, in water to be treated, between a water quality index and a concentration of a pollution component having no causal relationship with the water quality index, from a result of sample analysis of the water to be treated performed periodically;

a first pollution component concentration estimator configured to, under a condition that there is the correlation, statistically analyze a distribution of measurement values of the water quality index in a previous certain period of the water to be treated, and based on a result of the statistical analysis and the correlation, estimate the concentration of the pollution component of the water to be treated;

a second pollution component concentration estimator configured to, on a condition that the correlation is absent, statistically analyze a distribution of concentration of the pollution component in past sample analyses of the water to be treated, and based on a result of the statistical analysis, estimate the concentration of the pollution component of the water to be treated; and

an operating condition determiner configured to select one of the first pollution component concentration estimator and the second pollution component concentration estimator based on a determination of the correlation determiner, and to determine an operating condition of the water treatment plant for treating the water to be treated based on the concentration of the pollution component of the water to be treated estimated by the selected estimator.

13. (canceled)

14. A water treatment plant controlling method comprising:

a correlation determination step of determining whether or not there is a correlation, in water to be treated, between a water quality index and a concentration of a pollution component having no causal relationship with the water quality index, from a result of sample analysis of the water to be treated performed periodically;

a first pollution component concentration estimation step of, on a condition that there is the correlation, statistically analyzing a distribution of measurement values of the water quality index in a previous certain period of the water to be treated, and based on a result of the statistical analysis and the correlation, estimating the concentration of the pollution component of the water to be treated;

a second pollution component concentration estimation step of, on a condition that the correlation is absent, statistically analyzing a distribution of concentration of the pollution component in all past sample analyses of the water to be treated, and based on a result of the statistical analysis, estimating the concentration of the pollution component of the water to be treated; and

selecting one of the first pollution component concentration estimation step and the second pollution component concentration estimation step based on a determination of the correlation determination step, and determining an operating condition of a water treatment plant for treating the water to be treated based on the concentration of the pollution component of the water to be treated estimated by the selected estimation step.

15. A non-transitory computer-readable storage medium storing a water treatment plant controlling program for causing a computer to execute a process, comprising:

a correlation determination procedure of determining whether or not there is a correlation, in water to be treated, between a water quality index and a concentration of a pollution component having no causal relationship with the water quality index, from a result of sample analysis of the water to be treated performed periodically;

a first pollution component concentration estimation procedure of, on a condition that there is the correlation, statistically analyzing a distribution of measurement values of the water quality index in a previous certain period of the water to be treated, and based on a result of the statistical analysis and the correlation, estimating the concentration of the pollution component of the water to be treated;

a second pollution component concentration estimation procedure of, on a condition that the correlation is absent, statistically analyzing a distribution of concentration of the pollution component in all past sample analyses of the water to be treated, and based on a result of the statistical analysis, estimating the concentration of the pollution component of the water to be treated; and

selecting one of the first pollution component concentration estimation procedure and the second pollution component concentration estimation procedure based on a determination of the correlation determination procedure, and determining an operating condition of the water treatment plant for treating the water to be treated based on the concentration of the pollution component of the water to be treated estimated by the selected estimation procedure.

16. A water treatment system comprising:

a water treatment plant;

a measurement device for measuring a water quality index of water to be treated in the water treatment plant; and

a controller that controls the water treatment plant, wherein

the controller includes;

a correlation determiner configured to determine whether or not there is the correlation, in water to be treated, between a water quality index and a concentration of a pollution component having no causal relationship with the water quality index, from a result of sample analysis of the water to be treated performed periodically;

a first pollution component concentration estimator configured to, under a condition that there is the correlation, statistically analyze a distribution of measurement values of the water quality index in a previous certain period of the water to be treated, and based on a result of the statistical analysis and the correlation, estimate the concentration of the pollution component of the water to be treated;

a second pollution component concentration estimator configured to, on a condition that the correlation is absent, statistically analyze a distribution of concentration of the pollution component in all past sample analyses of the water to be treated, and based on a result of the statistical analysis, estimate the concentration of the pollution component of the water to be treated; and

an operating condition determiner configured to select one of the first pollution component concentration estimator and the second pollution component concentration estimator based on a determination of the correlation determiner, and to determine an operating condition of the water treatment plant for treating the water to be treated based on the concentration of the pollution component of the water to be treated estimated by the selected estimator.