JP2009000673A - Apparatus and method for monitoring water purification process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for monitoring a water purification process, each of which is used as a water quality monitor-control system of the water purification process of a purification plant and by each of which safe drinking water can be supplied stably while decreasing the infection with pathogenic bacteria. <P>SOLUTION: The apparatus for monitoring the water purification process, which is used for purifying raw water to obtain drinking water, is provided with: a pathogenic bacterium measurement system for measuring the number concentration of pathogenic bacteria in raw water; and a unit for detecting whether the measured number concentration of pathogenic bacteria in the raw water is equal to or higher than a preset value of the preset number concentration. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a water quality monitoring / control system for a water purification process in a water purification plant, which reduces infection by pathogenic insects and enables stable supply of safe drinking water.

In water purification treatment, a method in which coagulation sedimentation and sand filtration treatment are combined is widely adopted.
In the rapid filtration basin, suspended substances in the raw water are coagulated and precipitated with chemicals (flocculant), and then this treated water is passed through the granular layer of the sand filter basin filled with filter sand at a relatively high flow rate, mainly as a filter medium. Remove turbidity by adhering to and sieving in the filter layer. Even if the raw water is low in turbidity, pre-treatment with a flocculant is not possible because sufficient removal of the colloidal suspended solids cannot be expected simply by filtering through a rapid filtration pond.

  The rapid filtration basin is used as the final stage of turbidity in the water purification process, and it provides a purification function that can provide filtered water that conforms to the water quality standards and Non-Patent Document 1, a turbidity retention function, a buffering function against fluctuations in water quality, and filtration. Sufficient cleaning functions such as back-flow cleaning to remove suspended matter retained in the tank are required.

Ministry of Health, Labor and Welfare Notification “Provisional Guidelines for Cryptosporidium in Waterworks” (2001)

The process control of filtered water is currently performed using turbidity as an index.
Turbidity management based on Non-Patent Document 1 is an index for directly evaluating the removal performance of Cryptosporidium, although it can be an index for judging whether or not each process of aggregation, precipitation, and filtration functions well. Is not enough.

  Since Cryptosporidium is a microorganism, the method for directly detecting its presence is not an inspection method using a microscope, and its measurement takes about 4 days. For this reason, when the measurement results in question are obtained, the previous four days are already after being consumed and consumed in the state of the water in question, and it is extremely difficult to reflect this method in daily management.

  For this reason, in water purification facilities that may be contaminated with Cryptosporidium, the coagulant is excessively injected for safety, and is often managed on a daily basis, and chemical consumption and sludge generation are more than necessary. We have a problem of increasing.

  In view of the above-described problems, the present invention provides a monitoring device and a method for a water purification process including a pathogen measuring system that can measure waterborne infectious microorganisms such as Cryptosporidium in raw water in a short time. .

  In order to achieve the above-described object, the present invention provides a water purification process monitoring device for purifying raw water, wherein the water purification process monitoring device has a number concentration of pathogenic insects in the raw water equal to or higher than a preset value. It is a pathogen count concentration measuring system having a function of detecting this and outputting a signal, and controls the operating condition of the water purification process when a preset number concentration or more is detected. Thus, the quality of purified water can be maintained (invention of claim 1).

  In the embodiment of the water purification process monitoring apparatus according to the present invention, the pathogen measurement system includes a separation and concentration unit configured by a filter, and fine particles containing the pathogen captured on the filter surface. The washing water is made to flow backward from the filtered water side of the filter and collected as a sample solution containing fine particles and Cryptosporidium, and a labeled antibody that specifically binds to the pathogen in the collected sample solution is supplied. An antibody reaction part that reacts and binds to the labeled antibody and a detection part for a pathogen that is bound to the labeled antibody are provided (invention of claim 2).

Furthermore, when a preset number concentration or more is detected, a particle measuring device that continuously counts particles larger than the size of the pathogen to be detected in the filtered water from the filtration step of the water purification process ( For example, the monitoring is strengthened by using a fine particle counter.
Further, in the embodiment of the present invention, the preset value of the number concentration can be arbitrarily set according to the removal capability of the water purification facility in the above-described water purification process monitoring apparatus (claim). Item 4).

  Then, Cryptosporidium that can be captured by a filter having a pore diameter of 3 μm or less can be monitored (invention of claim 5). In other words, by having a pathogen measuring system that can measure the number concentration of water-borne infectious microorganisms in raw water, such as Cryptosporidium, the number concentration of Cryptosporidium in raw water is ascertained. When the number concentration is higher than the set value of the steady number concentration of the raw water (usually set to a number concentration that is at least one digit higher than the steady value), the filtered water from the filtration process is measured with a particle counter such as a particle counter. By continuously counting particles of 3μm or more, the number of particles of Cryptosporidium equivalent diameter of 3μm or more in the filtered water is continuously monitored, and the operating conditions of the water purification process are controlled according to the measurement results, and the quality of the purified water Can be secured. Thereby, the safety of purified water can be ensured even when the number concentration of pathogenic insects in the raw water increases and the water quality is such that the number concentration exceeds the removal capacity of the water purification facility.

  In the present invention, in the water purification process monitoring method for purifying the raw water, the raw water before the water purification treatment is collected, the number of pathogenic insects in the raw water is measured, and the number concentration of the pathogenic insects in the measured raw water is determined in advance. A signal is output when the value is equal to or greater than the set value, and the operation condition of the water purification process is controlled based on the signal (invention of claim 6).

  The above-mentioned measurement of the number of pathogens in the raw water is performed by filtering the raw water in the separation and concentration unit, collecting fine particles containing the pathogens captured by the filtration in the separation and concentration unit, and specifically binding to the pathogens to be detected. The presence of a pathogen can be determined by measuring the fluorescence with an antigen-antibody reaction using a fluorescently labeled antibody and measuring fluorescence (invention of claim 7).

  Furthermore, when the number of pathogens in the raw water is measured and the number concentration of pathogens in the raw water is higher than the set value of the steady number concentration of the raw water in the water purification plant, Fine particles larger than the size of the pathogen to be detected in the filtered water are counted, and the operating condition of the water purification process can be controlled according to the result of the fine particle measurement to maintain the quality of the purified water (invention of claim 8). .

  The concentration of pathogens in the raw water was measured in a water purification process that had the process of collecting raw water, coagulating it in a mixing pond, separating the turbidity components in a sedimentation basin through floc formation, and obtaining filtered water in the filtration process. The operating conditions of the water purification process controlled by the value of water are discharged at the time of control of water intake, stop operation of water intake, control to increase the flocculant injection rate and stirring intensity G value of the floc formation pond, or backwashing of the filtration process The water is discharged into the sewer without returning it to the raw water, the pathogen concentrated in the filtration process is inactivated, or the pathogen is removed by membrane filtration and returned to the raw water. 9 invention).

  INDUSTRIAL APPLICABILITY The apparatus and method for monitoring a water purification process according to the present invention are used in a water purification system having a system capable of measuring a bacterium such as cryptosporidium and other water-borne infectious microorganisms such as viruses in a short period of time. Thus, it is possible to quickly respond to contamination of raw water by chlorine-resistant pathogens that could not be dealt with conventionally, so that the safety of water quality can be improved.

Embodiments of a water purification process monitoring apparatus and method according to the present invention will be described below with reference to the accompanying drawings.
First, FIG. 1 shows a general embodiment of an overall configuration diagram of a water purification process monitoring apparatus according to the present invention.

In the present embodiment, the raw water is supplied to the mixing pond 1 and simultaneously sent to the pathogen measuring system 8.
Injecting flocculant from the flocculant tank 2 in the mixing pond 1 into raw water taken from rivers, etc., separating the turbidity components in the sedimentation basin 4 through the floc-forming pond 3, and sand filtering in the filtration basin 5 Is done.
The pathogen measuring system 8 collects raw water before entering the mixing pond 1 and monitors the number of pathogenic insects in the raw water. If a number concentration is observed such that the pathogenic insects in the raw water exceed the removal performance by coagulation sedimentation and sand filtration, a signal is output from the pathogen measuring system 8 according to the number concentration (in the figure). By controlling the amount of water intake and stopping the water intake, or increasing the flocculant injection rate and the agitation strength G value of the floc formation pond, or the water discharged during backwashing of the filtration basin is used as raw water. Discharge into the sewer without returning, or inactivate (ozone treatment) or remove (membrane filtration) pathogenic insects concentrated in the filtration pond, operate the inactive treatment device 7 and return it to the raw water .

Usually, it is preferable that the measured value of the pathogen measuring system 8 according to the present invention changes at a value of 1 piece / 20 L or less. Within this range, the removal rate of Cryptosporidium in a water purification system that has been properly subjected to water treatment by coagulation sedimentation and rapid filtration is about 3 logs, so the annual permissible target set by the US Environmental Protection Agency (USEPA) The infection risk of 10 ^-4 or less can be secured.

  Depending on the location conditions of the water purification facility, there may be an inflow of wastewater from the sewage treatment plant in the upstream area or livestock wastewater, or the riverbed sediments may be rolled up during rainfall. The number concentration of pathogenic insects contained in normal raw water is several / 20L or less, but this increases the number concentration to 10 to 100 / 20L, which is one digit higher than usual. There is sex. For this reason, the normal water purification method may not be able to remove the permissible infection risk level or less, and there is a risk that pathogens exceeding the permissible infection risk concentration will be mixed in the clean water.

However, in the monitoring apparatus and method of the water purification process according to the present invention, when pathogenic insects flow in at a number concentration exceeding the water purification capacity based on the measurement result of the pathogen measuring system 8, the amount of water intake is suppressed at an early stage. It can be performed. Furthermore, the removal rate is secured by increasing the injection rate of the commonly used aluminum flocculant and adding an iron flocculant, and the annual permissible infection risk of water purification is kept below 10 ^-4. be able to.

  In addition, when the number concentration of pathogenic insects in the raw water is detected to be equal to or higher than a preset value of the number concentration, fine particles containing pathogenic insects of 3 μm or more in the filtered water from the filtration pond are further detected by the particle counter 6. The counter is continuously counted. Thereby, depending on the measurement result, the operating conditions of the water purification process (control of the water intake, stop operation of water intake, control to increase the flocculant injection rate and stirring strength G value of the floc formation pond, or backwash of the filtration basin To control the operation of discharging the discharged water into the sewer, inactivating the pathogens concentrated in the filtration pond, and removing the pathogens through membrane filtration and returning them to the raw water) to ensure the safety of the purified water quality be able to.

Next, an embodiment in which the pathogen measuring system 8 in the water purification process monitoring apparatus and method according to the present invention is employed and particularly cryptosporidium is detected will be described.
First, FIG. 2 shows a processing flow as an embodiment of the pathogen measuring system 8.

In this Embodiment, the raw | natural water 100 branched and taken out before the introduction to a water purification process is supplied to the storage tank 102, and the sample preparation agent 104 is added. Since the raw water 100 removes dust larger than 100 μm in the raw water as needed, it can be passed through a 100 μm mesh filter or the like when supplied to the storage tank 102.
The sample preparation agent 104 is a membrane filtration using a surfactant that functions as a turbid dispersant that makes it easy to peel off pathogens captured by a filter, which will be described later, and a chromaticity component (soluble organic matter) such as humic acid in raw water. Hydrochloric acid can be mentioned as an additive material for preventing performance degradation. As the surfactant, SDS (sodium dodecyl sulfate) or the like can be used.

The sample adjusted in the storage tank 102 is sent to a separation / concentration unit 106 constituted by a filter having a pore diameter of 2 μm. Separation and concentration unit 106 concentrates fine particles containing Cryptosporidium by filtration using a filter having a pore diameter of 2 μm.
The microparticles containing Cryptosporidium trapped on the filter surface are recovered as a sample solution containing the microparticles and Cryptosporidium by causing the washing water to flow backward from the filtered water side of the filter in the separation and concentration unit 106.

The collected sample solution separated and concentrated by the separation and concentration unit 106 is sent to the antibody reaction unit 108.
In the antibody reaction unit 108, the fluorescently labeled antibody 110 that specifically binds to the detection target cryptosporidium and the detection target cryptosporidium in the collected sample solution are combined by an antigen-antibody reaction. At this time, when one kind of fluorescently labeled antibody is used, there is a possibility that a fluorescently labeled antibody that is non-specifically bound to a contaminant is determined as a false positive. For this reason, it is preferable to prepare a plurality of antibodies having different antigen recognition sites and to multiplexly label Cryptosporidium with a fluorescently labeled antibody in which fluorescent substances having different fluorescence wavelengths are bound thereto. Thereby, the detection accuracy of Cryptosporidium to be detected can be improved.
The antibody itself can be obtained by a technique known to those skilled in the art. The antibody can be used regardless of its kind, such as a polyclonal antibody or a monoclonal antibody, as long as it has specificity for the pathogen to be detected. In general, a monoclonal antibody is preferable because of its excellent specificity.

Next, the recovered sample solution labeled with the fluorescently labeled antibody 110 is sent to the detection unit 112.
The detection unit 112 includes a fluorescence scattered light measuring instrument for measuring the fluorescence scattered light intensity. In the detection unit 112, the fluorescence scattered light intensity of Cryptosporidium to be detected to which the fluorescent labeled antibody is bound is measured by a fluorescence scattered light measuring instrument. The measurement data is sent to the determination unit 114.

  The detection unit 112 is preferably configured to be capable of simultaneously measuring a plurality of fluorescence wavelengths when performing multiple labeling using a plurality of fluorescently labeled antibodies.

  Moreover, since there is usually very little Cryptosporidium to be detected in the sample, there is a possibility that it cannot be detected by one measurement. Therefore, the sensitivity of detection of Cryptosporidium to be detected can be increased by circulating it through the detector and repeatedly measuring it (116 in the figure).

In addition, the pathogen measuring system according to the embodiment of FIG. The sample storage unit 118 determines whether to store the sample measured by the determination unit 114 based on the measurement data detected by the detection unit 112. When confirming the reproducibility of the collected sample, the stored sample is again added to the detection unit 112 again to detect Cryptosporidium (120 in the figure).
On the other hand, when a pathogenic insect to be detected is detected, the sample discharged from the detection unit 112 is received in a storage container and stored (122 in the figure). The stored sample can be provided to a test for determining whether contaminating Cryptosporidium is alive and / or a test for determining whether it is infectious. Unnecessary samples are discarded as drainage (124 in the figure).

  Next, FIG. 3 shows the configuration of the pathogen measuring system 8 in FIG. 1 as an embodiment that employs the pathogen measuring system 8 in the water purification process monitoring apparatus and method according to the present invention, and particularly detects Cryptosporidium. This will be described below while clarifying the function of each component.

  In this Embodiment, the raw | natural water 9 branched and taken out before the introduction to a water purification process is supplied to the storage tank 13 with the raw | natural water supply pump 10. FIG. Subsequently, the sample adjusting agent 11 is supplied to the storage tank 13 by the sample adjusting agent supply pump 12 and mixed. The sample conditioner is reduced in membrane filtration performance due to chromaticity components (soluble organic matter) such as surfactant and humic acid in raw water that function as a turbid dispersant that makes it easy to peel off Cryptosporidium trapped in the filter described later Hydrochloric acid can be mentioned as an additive substance for preventing the above.

  The sample adjusted in the storage tank 13 is then sent to the separation and concentration unit 18 via the pump 15. At this time, it is determined by the water level in the storage tank 13 by the level meter 14 that all the sample liquid in the storage tank 13 has been sent to the separation and concentration unit 18. In the separation and concentration unit 18, the sample is filtered using a filter having a pore size of 3 μm, and fine particles larger than 3 μm containing Cryptosporidium are captured and concentrated on the filter surface.

Fine particles containing Cryptosporidium trapped on the filter surface are supplied to the separation / concentration section 18 by the washing water supply pump 17 by the washing water 16, and the washing water 16 is caused to flow backward from the filtered water side of the filter. It collects as a sample liquid containing. As the washing water 16, it is preferable to use a solution obtained by mixing a surfactant with pure water and further adjusting the pH to neutral.
The collected sample solution is supplied to the antibody reaction unit 22 via the pump 19.

  In the antibody reaction unit 22, a fluorescently labeled antibody 20 that specifically recognizes cryptosporidium is injected by a fluorescently labeled antibody supply pump 21 and mixed with a sample. At this time, when one kind of fluorescently labeled antibody is used, there is a possibility that the fluorescently labeled antibody that is nonspecifically bound to the contaminant is judged as false positive. For this reason, multiple Cryptosporidium detection accuracy is improved by preparing multiple antibodies with different antigen recognition sites and multiple-labeling Cryptosporidium with fluorescent substances with different fluorescence wavelengths attached to each of them. This is preferable.

  The antigen-antibody reaction with many commercially available antibodies is 20 to 30 minutes at 37 ° C. and 1 hour or more at room temperature, and in order to measure more frequently, after mixing the sample and the labeled antibody, It is preferable that the mixed liquid be transferred to another container so that the next sample can be supplied.

  Furthermore, in order to measure Cryptosporidium at a high frequency, it is preferable to prepare a plurality of separation / concentration units 18 and antibody reaction units 22 and supply them to separate separation / concentration units and antibody reaction units for each sample by switching valves or the like.

  In order to advance the antigen-antibody reaction efficiently, the antibody reaction part 22 is preferably equipped with a thermostat that keeps the sample temperature at 37 ° C. The sample for which the antigen-antibody reaction has been completed is supplied to the detection unit 27 by the pump 24. At this time, the sheath fluid 25 is also supplied to the detection unit 27 by the sheath fluid supply pump 26.

The detection unit 27 includes a fluorescence scattered light measuring instrument for measuring the fluorescence scattered light intensity. The detection unit 27 measures the fluorescence intensity of Cryptosporidium bound with the fluorescently labeled antibody, and sends the measurement data to the determination unit 28. When multiple labeling using a plurality of fluorescently labeled antibodies is performed, it is preferable that the measurement unit be capable of simultaneously measuring a plurality of fluorescence wavelengths.
The determination unit 28 determines whether or not sample storage is necessary based on the measurement data detected by the detection unit 27. Furthermore, the mixing level of Cryptosporidium contained in the raw water can be grasped based on the measurement data, and feedback control can be performed for the water purification process.

After the measurement by the detection unit 27 is completed, the sample is sent to the sample storage unit 29.
In the sample storage unit 29, when Cryptosporidium is detected, the sample discharged from the detection unit 27 is received and stored in the sample storage container 30 by the flow path switching valve 31. The stored sample can be submitted to the test to determine if contaminating Cryptosporidium is alive and / or whether it is infectious. Samples that do not need to be stored are drained.

In order to improve the detection accuracy, it is preferable that the sample is circulated to the detection unit 27 through a circulation channel from the sample storage unit 29 to the channel switching valve 23 and repeatedly measured.
In the present embodiment, the sample is sent to the detection unit 27 by the pump 24 and measured, and then the sample is circulated by the flow path switching valve 31 to repeatedly measure fluorescence. This integrates the measurement data and improves the detection probability of Cryptosporidium having a low number concentration.
Note that it is preferable to set the circulation and disposal of the sample by switching the flow path switching valve 31 based on the measurement data.

  With the pathogen measurement system of this embodiment, it can be done in about 1 hour from the separation and concentration of Cryptosporidium from raw water to the preparation of the measurement sample, and the total measurement time can be within 3 hours. Compared with the method, it becomes possible to measure frequently in a short time.

It is a conceptual diagram which shows the outline | summary of the monitoring apparatus of the water purification process of the Example which concerns on this invention. It is a figure of the processing flow which shows the outline | summary of the pathogen measuring system of the Example which concerns on this invention. It is a conceptual diagram explaining embodiment of the pathogen measuring system of the Example which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mixing pond 2 Coagulant tank 3 Flock formation pond 4 Sedimentation basin 5 Filtration basin 6 Fine particle counter 7 Inactive processing device 8 Pathogen measuring system 9 Raw water 10 Raw water supply pump 11 Sample conditioner 12 Sample conditioner supply pump 13 Reservoir 14 Level meter 15 Pump 16 Washing water 17 Washing water supply pump 18 Separation and concentration unit 19 Pump 20 Fluorescent labeled antibody 21 Fluorescent labeled antibody supply pump 22 Antibody reaction unit 23 Flow path switching valve 24 Pump 25 Sheath liquid 26 Sheath liquid supply pump 27 Detection unit 28 Determination Unit 29 Sample Storage Unit 30 Sample Storage Container 31 Channel Switching Valve

Claims (9)

  In the water purification process monitoring apparatus for purifying raw water, the process monitoring apparatus detects that the number concentration of pathogenic insects in the raw water is equal to or higher than a preset value and outputs a signal. An apparatus for monitoring a water purification process, comprising a number concentration measurement system, which controls operating conditions of a water purification process and maintains the quality of purified water when a preset number concentration value or more is detected. In the monitoring device of the water purification process according to claim 1,
The pathogen count concentration measuring system is
A separation and concentration unit constituted by a filter;
Supplying a labeled antibody that specifically binds to the pathogen in the sample from which the microparticles containing the pathogen captured on the filter surface have been collected, and reacting and binding the pathogen to the labeled antibody; and
A water purification process monitoring device comprising: a pathogen detection unit coupled with a labeled antibody. In the monitoring apparatus of the water purification process in any one of Claims 1-2,
It is further equipped with a fine particle measuring device that can measure fine particles, and when the number concentration of pathogens in the raw water is higher than the set value of the steady number concentration of raw water in the water purification plant, filtration in the filtration process of the water purification process Fine particles larger than the size of pathogenic insects to be detected in water are continuously counted by the fine particle measuring device, and the operating conditions of the water purification process are controlled according to the measurement results to maintain the purified water quality. Monitoring device for water purification process. In the monitoring apparatus of the water purification process in any one of Claims 1-3,
The preset value of the number concentration can be arbitrarily set according to the removal capacity of the water purification facility. In the monitoring apparatus of the water purification process in any one of Claims 1-4,
An apparatus for monitoring a water purification process, wherein the pathogen is Cryptosporidium. In the monitoring method of the water purification process that purifies raw water,
Sample raw water before water purification treatment, measure the number of pathogenic insects in the raw water, and output a signal when the measured number concentration of pathogenic insects in the raw water is greater than or equal to a preset value, the signal The control method of the water purification process characterized by controlling the operating condition of the water purification process based on the above and maintaining the quality of the purified water. In the monitoring method of the water purification process of Claim 6,
The measurement of the number of pathogens in the raw water is performed by filtering the raw water with a separation and concentration unit, collecting fine particles containing the pathogens captured by the filtration of the separation and concentration unit, and specifically binding to the pathogens to be detected. A method for monitoring a water purification process, characterized in that an antigen-antibody reaction is carried out with a fluorescently labeled antibody, and the presence of a pathogen is judged by fluorescence measurement. In the monitoring method of the water purification process of Claims 6-7,
In the filtration step of the water purification process, when the number concentration of the pathogens in the raw water is higher than the set value of the steady number concentration of the raw water in the water purification plant by the measurement of the number of pathogens in the raw water, Monitoring the water purification process characterized by counting fine particles larger than the size of pathogens to be detected in filtered water, controlling the operating conditions of the water purification process according to the measurement results of the fine particles, and maintaining the quality of the purified water Method. In the monitoring method of the water purification process of Claims 6-8,
The raw water is taken and coagulated in the mixing pond, the turbidity component is separated in the sedimentation basin after flock formation, and the filtered water is obtained in the filtration process. Control to increase the flocculant injection rate and floc formation pond agitation value, or to drain the drainage water during backwashing in the filtration process to the sewer, and to remove pathogens concentrated in the filtration process A method for monitoring a water purification process, characterized in that it is at least one of an operation to inactivate and an operation to remove pathogenic insects through membrane filtration and return to raw water.

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