JPH1137969A - Abnormal water quality detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormal water quality detector for detecting the abnormality water quality of a liquid to be measured accurately and surely. SOLUTION: The abnormal water quality detector includes a detecting electrode section 1 comprising a case 26, and a microorganism membrane 21 holding an iron bacteria provided in the case 26. A detecting channel 27 is arranged contiguously to the microorganism membrane 21. A mixture of a liquid to be measured, a liquid containing ferrous iron and a PH conditioning buffer flows into the detecting channel 27. The mixed liquid passed through the microorganism membrane 21 and flows into the case 26 thus causing a current flow between a detecting electrode 23 and a counter electrode 24 encased therein. When the mixed liquid flows through the microorganism membrane 21, the ferrous salt in the mixed liquid is converted into a ferric iron through ferrous bacteria and the current level is varied between the detecting electrode 23 and the counter electrode 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormal water quality detecting device which is installed in a water purification plant or a sewage treatment plant and can detect an abnormal water quality of inflowing treated water.

[0002]

2. Description of the Related Art Water purification plants collect and process river water to supply drinking water. In this case, when abnormal water quality occurs, such as when harmful substances that cannot be removed by normal treatment are mixed in the river water, an emergency situation of stopping water intake may occur. Similarly, at the sewage treatment plant, the inflowed sewage is treated with activated sludge, so that abnormal water quality such as the incorporation of harmful substances into the inflowed sewage greatly affects sewage treatment.

For this reason, it is necessary to detect the abnormal quality of the inflow water in advance at the water purification plant and the sewage treatment plant, or at the latest at the time of inflow. Conventionally, a water tank is provided at the entrance of a water purification plant and a sewage treatment plant, and fish are bred in the water tank, and the abnormal behavior of the influent water is detected by observing the behavior, lethality, and the like of the fish. In addition, in order to reduce the load on the observer, an apparatus that automatically monitors the behavior and state of fish in an aquarium using image processing has been considered.

[0004]

However, it takes a long time for fish bred in an aquarium to behave abnormally or die due to inflow of water, so that it takes a long time to detect abnormal water quality. . In addition, a fish tank for breeding fish, a monitoring device, and the like are large and have a complicated structure. Furthermore, the behavior of fish may be affected by the health condition and the surrounding environment where the aquarium is installed, and the degree of the effect differs depending on the type of fish. As a result, the sensitivity of abnormality detection by the automatic monitoring device using image processing is reduced, and in some cases, erroneous detection of water quality abnormality may occur.

[0005] The present invention has been made in view of the above points, and an abnormal condition that can detect the abnormal water quality of inflow water to a water purification plant or a sewage treatment plant in a short time, accurately and with high sensitivity. It is an object to provide a water quality detection device.

[0006]

According to the present invention, there is provided a detection electrode unit having a case having a microbial membrane holding iron bacteria on one side thereof and having an internal solution, and a pair of electrodes disposed in the case. A detection flow channel provided adjacent to the case and in contact with the microbial membrane, a test liquid supply device for supplying the test liquid to the detection flow channel, and supplying a ferrous iron-containing liquid to the detection flow channel A ferrous-containing liquid supply device;
A pH adjusting buffer solution is supplied into the detection channel to set the pH of a mixture of the liquid to be measured, the ferrous-containing solution, and the PH adjusting buffer solution at the detection electrode portion to a constant value. An abnormal water quality detection device, comprising: a supply device, and a calculation unit that measures a current value flowing between a pair of electrodes of the detection electrode unit to detect the abnormal water quality of the liquid to be measured, and one surface thereof. A case provided with a microbial membrane holding iron bacteria and having an internal solution, a detection electrode portion having a pair of electrodes arranged in the case, and a detection flow channel provided adjacent to the case and in contact with the microbial membrane A liquid to be measured that supplies a liquid to be measured into the detection flow path; a liquid containing ferrous iron in the detection flow path; and a mixed liquid of the liquid to be measured and the liquid containing ferrous iron in the detection electrode unit. P that sets the PH of a fixed value
A reagent supply device that supplies a reagent containing an H-adjustment buffer, and a calculation unit that measures a current value flowing between a pair of electrodes of the detection electrode unit and detects an abnormal water quality of the liquid to be measured. It is an abnormal water quality detection device characterized by the following.

According to the present invention, the liquid to be measured, the ferrous-containing liquid, and the pH adjusting buffer are mixed in the detection channel to obtain a mixed liquid. The mixture flows into the case through the microbial membrane of the detection electrode portion, and a current flows between the pair of electrodes according to the oxygen concentration in the mixture. In this case, ferrous iron in the mixed solution is oxidized by the iron bacteria in the microbial membrane, and when abnormal water quality occurs in the liquid to be measured, the activity of the iron bacteria decreases, and the current value between the pair of electrodes changes. . The change in the current value is measured by the calculation unit, and the calculation unit detects the abnormal water quality of the liquid to be measured.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 are views showing an embodiment of the abnormal water quality detecting device according to the present invention.

As shown in FIG. 1, the abnormal water quality detection device includes a detection electrode 1 for detecting an abnormal water quality by passing a current through a liquid to be measured, and a storage tank in which the detection electrode 1 is stored in a liquid-tight state. 2 is provided.

The detection electrode section 1 detects dissolved oxygen in the liquid to be measured. The case 26 has a lower opening as shown in FIG. 2, and the lower opening of the case 26 utilizes oxygen. A microbial membrane 21 holding iron bacteria that converts ferrous iron to ferric iron, a gas permeable membrane 22 provided inside the microbial membrane 21, and a detection electrode 23 disposed in a case 26 below. And a holding body 28 attached thereto. An internal liquid 25 is stored in the case 26, and a counter electrode 24 is provided on the holder 28, so that a current flows between the detection electrode 23 and the counter electrode 24.

In the holder 28, lead wires 23a, 24a respectively connected to the detection electrode 23 and the counter electrode 24 are provided.
Is provided, and a detection flow path 27 that contacts the microbial membrane 21 of the detection electrode unit 1 is formed in the storage tank 2.

As shown in FIG. 1, a temperature controller 3 is provided so as to surround the storage tank 2, and the temperature controller 3 controls the temperature of at least a portion of the detection electrode unit 1 including the microbial membrane 21. It has become. Further, a liquid to be measured supply pump 6 for supplying the liquid to be measured to the detection channel 27 on the side of the detection electrode 1 via the pipe 5 is connected to the detection electrode section 1. Further, a ferrous-containing liquid tank 7 containing a ferrous-containing liquid and a buffer tank 8 containing a pH-adjusting buffer are connected to the pipe 5 via pipes 9 and 10, respectively. Ferrous-containing liquid supply pump 1 provided in each of 10
The first iron-containing liquid and the pH adjusting buffer are supplied from the first iron-containing liquid tank 7 and the buffer liquid tank 8 to the detection flow path 27 on the detection electrode unit 1 side by the first and the buffer supply pump 12. ing. In addition, the detection electrode unit 1 includes the detection electrode unit 1.
The arithmetic unit 13 is connected to amplify and convert current values from the detection electrode 23 and the counter electrode 24, and detect an abnormality in water quality of the liquid to be measured based on the current values. Furthermore,
Piping 5 between the measured liquid supply pump 6 and the detection electrode unit 1
Is connected to a gas supply device 14 for supplying gas so as to keep the oxygen concentration of the liquid in the pipe 5 constant.

1 and 2, a ferrous-containing liquid supply device is constituted by a ferrous-containing liquid tank 7 and a ferrous-containing liquid supply pump 11, and a buffer tank 8 and a buffer supply pump are provided. 12 constitute a pH adjusting buffer supply device.

Next, the operation of the present embodiment having the above configuration will be described. First, the liquid to be measured is supplied into the pipe 5 by the liquid to be measured supply pump 6. The ferrous-containing solution is fed from the ferrous-containing liquid tank 7 into the pipe 9 by the ferrous-containing liquid supply pump 11, and the buffer solution tank 8
Then, the buffer solution for PH adjustment is sent into the pipe 10 by the buffer solution supply pump 12. Then, the liquid to be measured, the ferrous-containing liquid, and the pH adjusting buffer are mixed in the pipe 5.

Here, first, a case is considered in which only the liquid to be measured containing no harmful substance flows into the detection channel 27 and comes into contact with the microbial membrane 21. In this case, oxygen corresponding to the concentration of dissolved oxygen in the liquid to be measured permeates through the gas permeable membrane 22 and diffuses in the internal liquid 25 of the case 26 and the detection electrode 23 and the counter electrode 2.
The current flows through the internal liquid 25 between the first and fourth liquids. For example, in a measurement in which air is supplied from the gas supply unit 14 to saturate the dissolved oxygen concentration in the liquid to be measured, a current flows as shown in part a of FIG. Is required. In the case of part a in FIG. 3, the consumption of oxygen by the iron bacteria in the microbial membrane 21 is extremely small.

Next, a mixed liquid comprising a ferrous-containing liquid, a pH adjusting buffer, and a liquid to be measured having no abnormality in water quality is caused to flow into the detection channel 27. In this case, the iron bacteria of the microbial membrane 21 oxidize ferrous iron to ferric iron using the dissolved oxygen as shown in the following formula, so that the amount of oxygen permeating the gas permeable membrane 22 decreases. An example of measurement in this case is part b in FIG. This measurement example is
Thiobacillus ferrooxidans (Thiobacillus ferrooxidans) as an iron bacterium retained on the microbial membrane 21
) Are used. As an iron bacterium, any microorganism having the above function can be applied to the present invention. However, from the availability and the results of many experiments conducted by the present inventors, Thiobacillus ferrooxidans (Th.
iobacillusferrooxidans), gallionella ferruginea (Gallionella ferruginea), leptospirillum ferrooxidans (Leptospirillum ferrooxidans),
Leptothrix, sperotilus (Spha
erotilus) has been found to be more suitable.

In the following description of the operation, iron bacteria
The case where Thiobacillus ferrooxidans is used will be described as an example. In FIG. 3, the difference between the currents of the part a and the part b is the oxygen consumption in the oxidation of iron by the iron bacteria when the measurement target liquid having no water quality abnormality is measured. In this case, since the activity of the iron bacteria of the microbial membrane 21, that is, the amount of iron oxidation, changes according to the temperature, the value of the part b in FIG. 3 is also affected. Since the temperature is adjusted by the vessel 3, the activity of iron bacteria is stabilized. It is also conceivable that the value of the part a shown in FIG. 3 changes with the concentration of dissolved oxygen in the liquid to be measured, but the air or oxygen concentration is adjusted to be constant just before the liquid to be measured is supplied to the detection electrode unit 4. The gas thus supplied is supplied from the gas supply device 14, and the liquid to be measured can be set to the saturated dissolved oxygen concentration, so that the concentration of dissolved oxygen in the liquid to be measured can be kept constant. Further, the concentration of the dissolved oxygen in the solution to be measured varies depending on the temperature of the solution. However, by adjusting the temperature of the microbial membrane 21 with the temperature controller 3, the concentration of the saturated dissolved oxygen in the solution to be measured can be kept constant.

Next, cyan, phenol,
Consider the case where harmful substances such as pesticides are mixed. In this case, when a mixed solution composed of the liquid to be measured, the ferrous-containing solution, and the pH adjusting buffer flows into the detection flow path 27, the iron bacteria of the microbial membrane 21 cause a decrease in activity or die. The amount of oxygen consumption is reduced. For example, when the cyan concentration in the liquid to be measured is 0.1 mg / L, a current flows as shown in part c in FIG. The change in the amount of oxygen consumed in the liquid mixture has a correlation depending on the concentration of the harmful substance. When the cyan concentration in the liquid to be measured is 0.05 mg / L, it becomes a part d in FIG. In this case, (a part-b part) and (a
Comparison of (part-c part) or (a-d part), or (c
The water quality abnormality can be detected from the comparison between (part-b part) and (d part-b part). In this way, the water quality abnormality is automatically detected by the calculation unit 13 and the alarm, guidance, and the like are calculated by the calculation unit 1.
3 is output.

Here, the microbial membrane 21 holding iron bacteria will be described. The microbial membrane 21 must always hold a certain amount of iron bacteria. As shown in FIG. 4 which is an experimental result of the present inventor, the retained amount was 5 × 1.
0 ^{7 to} 5 × 10 ⁹ cells are suitable. FIG.
In shows only up to 2 × 10 ⁹ cell, to gradually decrease the current difference far more 5 × 10 ^9, is substantially applicable to 5 × 10 ⁹ cell. As a method for retaining the iron bacteria on the microbial membrane 21, a method of filtering a solution containing a predetermined amount of iron bacteria through a resin membrane that allows water to pass but does not allow iron bacteria to pass therethrough, and attaches the iron bacteria to the membrane. is there. FIG. 3 shows a measurement example when the microbial membrane 21 manufactured by this method is used.

Further, in order to stably hold the iron bacteria on the microbial membrane 21 for a long period of time, the iron bacteria may be held using a gel-like fixing agent, for example, gellan gum. However, as the thickness of the microbial membrane 21 increases, the response time becomes slower, and the response to cyan also worsens. According to the experiment of the present inventor, as shown in FIG. 5, when the microbial membrane 21 was 4 mm thick, no response was observed even with a cyan concentration of 1 mg / L.
mm or less is suitable.

The iron bacteria of the microbial membrane 21 oxidize ferrous iron to ferric iron, and the present inventors have conducted experiments to determine that ferrous sulfate such as ferrous sulfate and ferrous chloride. 1
Iron salts can be used, of which iron bacteria
When Thiobacillus ferrooxidans was used, it was confirmed that ferrous sulfate was suitable. It has also been confirmed that the measured value is affected by the concentration of ferrous salt, and that the microbial membrane 21 has 5 × 10 ^{7 to} 5 × 10 ⁹ cells of Thiobacillus.
illus ferrooxidans and ferrous sulfate as ferrous iron
FIG. 6 shows an example of an experimental result when iron is used. As shown in FIG. 6, ferrous sulfate (FeSO
₄ · _7H 2 O) concentration has become a 0.1~5g / L.

The present inventor has also confirmed that the activity of iron bacteria is affected by the pH of the solution, and FIG. 7 shows an example of this result. As shown in FIG. 7, the pH of the mixed solution can be applied at PH1 to pH7, but it is necessary to maintain the PH of the mixed solution constant by a pH adjusting buffer.

Generally, ferrous iron is oxidized when oxygen in the air is dissolved to form ferric iron. Therefore, the ferrous iron-containing liquid tank 7 is airtight, and prevents dissolution of oxygen in the air.
Long-term stabilization can be achieved by removing dissolved oxygen already present in the ferrous solution. As this means,
Means 7a for supplying a gas containing no oxygen such as nitrogen gas to the ferrous liquid tank 7 to purge the ferrous solution.
May be provided. As another means, the same effect can be obtained by adding a deoxidizing agent such as sodium sulfite to the ferrous-containing liquid in the ferrous-containing liquid tank 7 from the adding means 7b.

The oxidation of ferrous iron is affected by PH, and at pH 8 or higher, it is rapidly oxidized by dissolved oxygen in the solution. For this reason, the ferrous iron-containing liquid must be maintained at a pH of 8 or less.
The following is effective. Therefore, as the pH adjusting buffer, the solution to be measured, the ferrous solution,
A pH adjusting buffer is used such that the pH of the mixture with the adjusting buffer is 5.5 or less. By using such a pH adjusting buffer, oxidation of ferrous iron can be almost suppressed and accurate measurement can be performed.

When a microorganism membrane 21 that has not been used for a long period of time is used, it may take a long time before stable measurement can be performed, the measurement may be unstable, or the measurement may not be performed. The present inventor has found that when the microbial membrane 21 is stored in a container (not shown) made of resin, metal, glass, or the like soaked in a ferrous-containing liquid and stored at a low temperature of 15 ° C. or less, Has been confirmed to be measurable. Furthermore, it has been confirmed that when the microbial membrane 21 is sealed so as not to contain gas, oxidation of ferrous iron can be suppressed, and long-term storage is possible.

Next, another embodiment of the present invention will be described with reference to FIG. In another embodiment shown in FIG. 8, a reagent tank 81 containing a reagent containing a ferrous solution and a pH adjusting buffer is connected to a pipe 5 via a pipe 82. Is substantially the same as the embodiment shown in FIGS.

In FIG. 8, the same portions as those of the embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 8, a reagent supply pump 83 is attached to a pipe 82, and the reagent in the reagent tank 81 is sent through the pipe 82 by the reagent
The liquid is mixed with the liquid to be measured in the chamber. The mixed liquid in the pipe 5 is sent to the detection channel 27 on the detection electrode unit 1 side.

According to the embodiment shown in FIG. 8, the first iron concentration in the reagent, as in the case of the embodiment shown in FIGS. 1 to 7, ferrous sulfate _(FeSO 4 · _7H 2 O ) Is 0.1 to 5 g / L. At this time, ferrous iron is easily oxidized, and in order to suppress the oxidation, it is effective to adjust the pH of the mixed solution to 5.5 or less. Therefore, by using an air-tight reagent tank 81 and using a buffer which can adjust the pH of the mixed solution to 5.5 or less as a pH adjusting buffer, oxidation of ferrous iron can be almost suppressed.

According to the embodiment shown in FIG. 8, the measurement can be performed with one reagent tank 81 and one reagent supply pump 83.

[0031]

As described above, according to the present invention, the abnormal water quality of the influent water of a water purification plant and a sewage treatment plant can be reduced in a short time, with high sensitivity, by utilizing the oxidizing action of ferrous iron bacteria.
An abnormal water quality detection device that can be accurately detected can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an abnormal water quality detection device according to the present invention.

FIG. 2 is an enlarged view showing a detection electrode unit of the abnormal water quality detection device shown in FIG.

FIG. 3 is an explanatory diagram showing the operation of the abnormal water quality detection device.

FIG. 4 is an explanatory diagram showing the relationship between the amount of iron bacteria held on the microbial membrane of the detection electrode unit and the current value.

FIG. 5 is a diagram showing an influence on a current value due to a thickness of a microbial membrane of a detection electrode unit.

FIG. 6 is a diagram showing the effect of the concentration of ferrous iron on the microbial membrane of the detection electrode unit on the current value.

FIG. 7 is a diagram showing an influence of a PH of a microbial membrane of a detection electrode unit on a current value.

FIG. 8 is a schematic configuration diagram showing another embodiment of the abnormal water quality detection device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Detection electrode part 2 Storage tank 3 Temperature controller 5, 9, 10, 82 Piping 6 Liquid supply pump to be measured 7 Ferrous-containing liquid tank 8 Buffer liquid tank 11 Ferrous-containing liquid supply pump 12 Buffer supply pump 13 Operation unit 14 Gas supply device 21 Microbial membrane 22 Gas permeable membrane 23 Detection electrode 24 Counter electrode 25 Internal liquid 26 Case 27 Detection flow path 81 Reagent tank 83 Reagent supply pump

Continuing on the front page (72) Inventor Takumi Hayashi 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Fuchu Plant, Toshiba Corporation (72) Inventor Satoshi Matsunaga 2-40 Sachicho, Fuchu-shi, Tokyo B-506 (72) Inventor Noriyuki Nakamura 2-24-31-20 Nakamachi, Koganei-shi, Tokyo

Claims (9)

[Claims] 1. A case having a microbial membrane holding an iron bacterium provided on one surface thereof and having an internal solution, a detection electrode portion having a pair of electrodes disposed in the case, and a detection electrode portion provided adjacent to the case. A detection flow path that contacts the microbial membrane together with the measurement liquid supply apparatus that supplies a liquid to be measured into the detection flow path; and a ferrous iron-containing liquid supply apparatus that supplies a ferrous-containing liquid into the detection flow path. A pH adjusting buffer solution is supplied into the detection flow path, and the PH of the mixed solution of the liquid to be measured, the ferrous-containing solution, and the PH adjusting buffer solution at the detection electrode portion is set to a constant value. An abnormal water quality detection device comprising: a buffer solution supply device; and a calculation unit that measures a current value flowing between a pair of electrodes of the detection electrode unit and detects an abnormal water quality of the liquid to be measured. 2. The abnormal water quality according to claim 1, wherein the microbial membrane is thiobals ferrooxidans, gallionella ferruginia, leptospirilum ferrooxidans, leptostrix, or sperotyls as an iron bacterium. Detection device. 3. The abnormal water quality detection device according to claim 1, wherein the microorganism membrane has a filtration membrane and iron bacteria attached to the filtration membrane by filtering an iron bacteria-containing solution. 4. The apparatus for detecting abnormal water quality according to claim 1, wherein the microbial membrane has an iron bacterium held and formed by a gel-like fixing agent. 5. The abnormal water quality detecting device according to claim 1, wherein the ferrous iron-containing liquid supply device has means for removing oxygen in the solution. 6. A pH adjusting buffer supply device, comprising: a P-mixture of a liquid to be measured, a ferrous-containing liquid, and a PH adjusting buffer.
2. The abnormal water quality detection device according to claim 1, wherein a pH adjusting buffer solution in which H is 1 to 7 is supplied. 7. The abnormal water quality detection device according to claim 1, wherein a temperature controller for maintaining a temperature near the microbial membrane at a constant temperature is provided in the detection electrode unit. 8. A gas supply device for supplying a gas to the detection flow path to keep a constant oxygen concentration in a mixed solution of the liquid to be measured, the ferrous-containing liquid, and the pH adjusting buffer. The abnormal water quality detection device according to claim 1, wherein: 9. A detection electrode section having a microbial membrane holding an iron bacterium on one side thereof and having an internal solution, a pair of electrodes disposed in the case, and a detection electrode section provided adjacent to the case. A detection flow path that contacts the microbial membrane together with the microbial membrane; a test liquid supply device that supplies the test liquid into the detection flow path; a ferrous iron-containing liquid in the detection flow path; A reagent supply device for supplying a reagent containing a pH-adjusting buffer for setting the pH of a mixed solution with 1-iron-containing solution to a constant value; An abnormal water quality detection device, comprising: a calculation unit that detects abnormal water quality of a measurement liquid.