JP6043216B2 - Method for treating water to be treated and treatment apparatus for water to be treated - Google Patents

Description

  The present invention relates to a method for treating water to be treated and a treatment apparatus for water to be treated.

  Conventionally, in the treatment method of treated water, for example, treated water containing a COD (Chemical Oxygen Demand) component is introduced into a biological treatment tank containing activated sludge in the state of floating sludge, The COD component is reduced by biological treatment.

  Biologically treated water (hereinafter also referred to as treated water) is mixed with activated sludge and supplied to a sedimentation tank provided downstream from the biological treatment tank. In the sedimentation tank, activated sludge and treated water are treated. Separated into water.

  In such a treated water treatment method, by adjusting the amount of treated water introduced into the biological treatment tank, the amount of activated sludge, etc., the COD component value is lowered, and the quality of treated water exceeds a certain level. It is carried out to maintain.

  As a method of maintaining the quality of treated water at a certain level or higher, conventionally, prior to the introduction of treated water into a biological treatment tank, the total number of bacteria contained in activated sludge is measured, and based on the measurement results, A method of adjusting the amount of water to be treated introduced into a biological treatment tank is known (for example, see Patent Document 1).

  However, in the method of Patent Document 1, it takes a certain number of days (for example, about 3 to 5 days) to measure the total number of bacteria, and blanks are generated before the measurement result of the total number of bacteria is reflected in the operating conditions. There was room for improvement.

  On the other hand, conventionally, an ultrasonic interface meter is installed in the settling tank, the sedimentation state of the activated sludge is observed by the interface meter, and aeration is performed based on the comparison result with the pre-patterned activated sludge sedimentation state. A method for adjusting the operating conditions of the tank is known (see, for example, Patent Document 2). According to this method, the operating conditions can be adjusted almost in real time.

Japanese Patent No. 4672816 Japanese Patent No. 3164235

  However, the present inventors have found that the state of water to be treated may not be determined only by the sedimentation state of activated sludge observed by an ultrasonic interface meter. That is, it has been found that even if the activated sludge settling state observed by the ultrasonic interface meter has the same pattern, it may be in an over-aerated state or in an overloaded state. Therefore, when adjusting the operating conditions of the biological treatment tank based only on the sedimentation state of the activated sludge observed by the ultrasonic interface meter, there is a risk of further adjusting the over-aerated state in the direction of over-aeration, There is a risk of further adjusting the overload state in the overload direction.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to be able to adjust operating conditions in real time, and more reliably maintain the quality of treated water at a certain level or higher. Another object of the present invention is to provide a method for treating water to be treated.

In order to achieve the above object, the present invention provides the following.
Introducing a treated water containing a COD component into a biological treatment tank containing activated sludge containing bacteria capable of degrading a COD component, and biologically treating the treated water;
Separating the activated sludge supplied from the biological treatment tank and the treated water in a sedimentation tank provided at a later stage than the biological treatment tank;
A step of measuring the state in the settling tank with an interface meter installed in the settling tank;
Measuring the number of bacteria in the activated sludge accommodated in the biological treatment tank;
And a step of adjusting operating conditions of the biological treatment tank based on a measurement result by the interface meter and a measurement result of the number of bacteria.

According to the said structure, the operating condition of a biological treatment tank is adjusted based on the measurement result by an interface meter, and the measurement result of the number of bacteria. It is rare that the state of the water to be treated (that is, whether it is in an over-aerated state or an overloaded state) determined from the measurement result by the interface meter is different from the actual state. Therefore, in the present invention, first, the operating conditions are adjusted primarily based on the measurement result by the interface meter. As a result, the operating conditions can be adjusted in real time. In addition, in the present invention, in rare cases, operation is performed based on the measurement result of the number of bacteria, in preparation for the case where the state of the water to be treated determined from the measurement result by the interface meter is different from the actual state Adjust the conditions. The measurement of the number of bacteria usually requires a certain amount of time (for example, about 3 to 5 days). However, if the measurement result of the number of bacteria is used, even when the state of the water to be treated determined from the measurement result by the interface meter is different from the actual state, the adjustment can be made again correctly. Therefore, the quality of the treated water can be more reliably maintained at a certain level or higher.
As described above, in the present invention, since the operating condition of the biological treatment tank is adjusted based on the measurement result by the interface meter and the measurement result of the number of bacteria, it is possible to adjust the operating condition in real time, and Thus, it becomes possible to maintain the quality of the treated water at a certain level or higher.

In the above configuration, the step of measuring the number of bacteria in the biological treatment tank is a step of measuring the number of ammonia oxidizing bacteria,
The step of adjusting the operating condition of the biological treatment tank is preferably a process of adjusting the operating condition of the biological treatment tank based on the measurement result by the interface meter and the measurement result of the number of ammonia oxidizing bacteria.

The present inventors have found that when the number of ammonia-oxidizing bacteria is larger than a preset upper limit value, it is in an over-aerated state.
According to the said structure, since the operating condition of a biological treatment tank is adjusted based on the measurement result of ammonia oxidation bacteria count, it becomes possible to adjust an operating condition more correctly.

In the above configuration, the step of measuring the state in the settling tank includes measuring the interface height between the treated water and the activated sludge treated in the settling tank,
The step of adjusting the operating condition of the biological treatment tank is preferably a process of adjusting the operating condition of the biological treatment tank based on the change with time of the interface height.

  According to the said structure, the operating condition of a biological treatment tank is adjusted based on the time-dependent change of the interface height of the to-be-processed water and activated sludge in the sedimentation tank. For example, when the interface rises, the number of bacteria (the sum of the number of bacteria having activity and the one having lost activity) is increasing. Usually, since the number of active bacteria is often increased, the adjustment of the operating condition is basically performed by reducing the activated sludge or increasing the supply amount of the treated water. As a result, it is possible to perform more reliable real-time adjustment of the operating conditions than to adjust the operation based on the amount of scum and whether or not the interface and the bottom of the layer can be grasped (see Patent Document 2). . Moreover, it is excellent in that it is simple because at least the change with time of the interface height may be confirmed.

  The said structure WHEREIN: It is preferable that the said to-be-processed water contains the condensed water which generate | occur | produces when the waste gas discharged | emitted when coke is produced from coal is cooled.

  Condensed water generated by cooling the exhaust gas discharged when coke is produced from coal contains a large amount of phenol and thiocyan, and it is particularly difficult to predict the residual amount of COD components in the treated water. Therefore, when the treated water is the condensed water, the effect of the present invention, that is, it is possible to adjust the operating conditions in real time, and the quality of the treated water is more than a certain level more reliably. The effect that it becomes possible to maintain at this time can be exhibited more remarkably.

The present invention further provides the following.
A biological treatment tank containing activated sludge containing bacteria capable of degrading COD components;
A settling tank for separating activated sludge supplied from the biological treatment tank and treated water to be treated, provided at a stage after the biological treatment tank,
An interfacial meter installed in the settling tank and measuring the state in the settling tank;
A measuring unit for measuring the number of bacteria in the activated sludge accommodated in the biological treatment tank;
An apparatus for treating water to be treated, comprising: a control unit that performs control for adjusting operating conditions of the biological treatment tank based on a measurement result by the interface meter and a measurement result of the number of bacteria.

According to the said structure, based on the measurement result by an interface meter, and the measurement result of the number of bacteria, control which adjusts the operating condition of a biological treatment tank is performed. It is rare that the state of the water to be treated (that is, whether it is in an over-aerated state or an overloaded state) determined from the measurement result by the interface meter is different from the actual state. Therefore, in the present invention, first, the operating conditions are adjusted primarily based on the measurement result by the interface meter. As a result, the operating conditions can be adjusted in real time. In addition, in the present invention, rarely, based on the measurement result of the number of bacteria, secondarily, in case the state of the water to be treated determined from the measurement result by the interface meter is different from the actual state. Adjust the operating conditions. The measurement of the number of bacteria usually requires a certain amount of time (for example, about 3 to 5 days). However, if the measurement result of the number of bacteria is used, even when the state of the water to be treated determined from the measurement result by the interface meter is different from the actual state, the adjustment can be made again correctly. Therefore, the quality of the treated water can be more reliably maintained at a certain level or higher.
As described above, in the present invention, since the control for adjusting the operation condition of the biological treatment tank is performed based on the measurement result by the interface meter and the measurement result of the number of bacteria, the operation condition can be adjusted in real time. In addition, it is possible to more reliably maintain the quality of the treated water at a certain level or higher.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to adjust the operating condition of the biological treatment tank in real time, and to maintain the quality of treated water more than a certain level more reliably.

It is a schematic diagram which shows the processing apparatus of the to-be-processed water which concerns on one Embodiment of this invention. (A) is a figure for demonstrating the principle which measures the state in a sedimentation tank with an ultrasonic interface meter, (b) measured the state of Fig.2 (a) with the ultrasonic interface meter. It is a schematic diagram of the screen which shows an example in the case of displaying the result at the time as an image. (A)-(d) is a figure which shows typically the image which can be obtained by the measurement by an ultrasonic interface meter. It is a flowchart which shows the operating condition adjustment process A which concerns on one Embodiment of this invention. It is a flowchart which shows the operating condition adjustment process B performed in a control part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a water treatment apparatus according to an embodiment of the present invention. As shown in FIG. 1, the water treatment apparatus 100 includes an aeration tank (biological treatment tank) 110, a bacteria count measurement unit 120, an oxygen supply unit 130, an oxygen concentration measurement unit 131, and an oxygen concentration control unit. 132, a sedimentation tank 150, a sludge amount control unit 160, and an ultrasonic interface meter 170. The oxygen concentration control unit 132 and the sludge amount control unit 160 correspond to the control unit of the present invention.

  The aeration tank 110 is a biological treatment tank also called a reaction tank or an aeration tank. The aeration tank 110 contains activated sludge containing bacteria capable of decomposing COD components, and treated water containing COD components such as coke oven wastewater is introduced. The coke oven drainage refers to water containing condensed water generated by cooling exhaust gas discharged when coke is produced from coal. In the aeration tank 110, organic substances in the water to be treated contained in the aeration tank 110 are absorbed and decomposed by aerobic microorganisms in the activated sludge.

  The bacterial count measuring unit 120 measures the number of bacteria in the activated sludge in the aeration tank 110 (the number of active bacteria involved in biological treatment). Examples of bacteria present in activated sludge include ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB), phenol degrading bacteria, thiocyan degrading bacteria, and the like. In the present embodiment, a case will be described in which the bacterial count measuring unit 120 measures the numbers of ammonia oxidizing bacteria (AOB) and total bacteria (authentic bacteria). In addition, since a conventionally well-known method (for example, refer patent 4672816) can be used for the measuring method of ammonia oxidation bacteria (AOB) and all the bacteria (authentic bacteria), detailed description here is abbreviate | omitted. . The structure of the bacteria count measurement unit 120 is not particularly limited as long as it can measure the number of bacteria. For example, the bacteria count measurement unit 120 collects a part of the activated sludge stored in the aeration tank 110, and the collected activated sludge. A structure having a purification unit for purifying DNA and a surveying unit for measuring the number of bacteria by a quantitative PCR method using a reaction solution containing the purified DNA, a PCR primer, and a probe can be used. The bacterial count measuring unit 120 measures the bacterial count regularly (for example, once a week). The bacterial count measured by the bacterial count measuring unit 120 is transmitted to the control unit as data relating to the bacterial count.

  The oxygen supply unit 130 is disposed at the bottom of the aeration tank 110 and supplies oxygen to the activated sludge stored in the aeration tank 110. Examples of the oxygen supply unit 130 include a diffuser.

  The oxygen concentration measurement unit 131 is stored in the aeration tank 110 and measures the oxygen concentration in the activated sludge stored in the aeration tank 110. An example of the oxygen concentration measurement unit 131 is an oxygen concentration meter.

The oxygen concentration control unit 132 is configured to measure the oxygen concentration in the activated sludge measured by the oxygen concentration measuring unit 131 based on the measurement result by the ultrasonic interface meter 170 described later and the number of bacteria measured by the bacterial number measuring unit 120. In order to control this, the amount of oxygen supplied by the oxygen supply unit 130 is controlled.
The oxygen concentration control unit 132 is configured to adjust the total number of bacteria (authentic bacteria) and the number of AOBs in the activated sludge to be within a preset range. Specifically, for example, the AOB number is larger than the preset upper limit value based on the measurement result by the ultrasonic interface meter 170, the number of bacteria measured by the bacteria number measurement unit 120, and the like (over-aeration state) ), The amount of oxygen supplied from the oxygen supply unit 130 to the activated sludge is reduced.

  The sedimentation tank 150 is provided in the subsequent stage of the aeration tank 110. In the settling tank 150, the activated sludge that has absorbed and decomposed organic matter in the aeration tank 110 and the water to be treated in which the COD component has been reduced in the aeration tank 110 (that is, treated water) are settled into treated water and activated sludge. .

  The sludge amount control unit 160 controls the amount of excess sludge discharged from the sedimentation tank 150 to the outside based on the measurement result by the ultrasonic interface meter 170 described later and the number of bacteria measured by the bacteria number measurement unit 120. . The sludge amount control unit 160 controls the discharge amount of excess sludge in order to control SRT (solid matter residence time), ASRT (aerobic solid matter residence time), and the like. Moreover, the sludge amount control part 160 controls the quantity of return sludge.

  A part of the extracted sludge extracted from the sedimentation tank 150 is returned to the aeration tank 110 as a return sludge, and the remaining part is discharged as excess sludge. In this case, the processing apparatus 100 further includes a return path to the aeration tank 110.

  The sludge amount control unit 160 is configured to adjust the total number of bacteria (authentic bacteria) and the number of AOBs in the activated sludge to be within a preset range. Specifically, for example, the AOB number is larger than the preset upper limit value based on the measurement result by the ultrasonic interface meter 170, the number of bacteria measured by the bacteria number measurement unit 120, and the like (over-aeration state) ), The amount of excess sludge withdrawn from the sedimentation tank 150 is increased, and the SRT or ASRT is adjusted to be shortened.

  The ultrasonic interface meter 170 is installed in the settling tank 150 and measures the state in the settling tank. In the ultrasonic interface meter 170, the state in the precipitation tank is measured continuously (for example, every few seconds). The measurement result obtained by the ultrasonic interface meter 170 is transmitted to the control unit as data relating to the measurement result. FIG. 2A is a diagram for explaining the principle of measuring the state in the sedimentation tank using an ultrasonic interface meter. FIG. 2A is a partially enlarged view of the ultrasonic interface meter 170 shown in FIG. 1 and the vicinity thereof. is there. The ultrasonic interface meter 170 includes a transceiver 170a capable of transmitting and receiving ultrasonic waves. The transceiver 170a is disposed so as to be positioned slightly below the liquid level 180 of the settling tank 150. When ultrasonic waves are emitted from the transmitter / receiver 170a in water (downward in FIG. 2A), the emitted ultrasonic waves are in various positions having different densities (for example, positions having sludge concentration differences from each other). Is reflected and reaches the transceiver 170a again. Since the speed of sound in water is constant, by measuring the time from when the ultrasonic wave is emitted from the transmitter / receiver 170a until it reaches the transmitter / receiver 170a and its reflection intensity, the interface depth of sludge and the state of sludge (for example, , Sedimentation state due to density difference) can be measured.

  For example, the time (corresponding to the height) from when the ultrasonic wave is emitted from the transmitter / receiver 170a to the transmitter / receiver 170a again is taken as the vertical axis, and the reflection intensity (corresponding to the density) is set at a position corresponding to the reflection time. If a corresponding color is given, the state in the sedimentation tank 150 can be displayed as an image.

  FIG. 2B is a schematic diagram of a screen showing an example in which the result when the state of FIG. 2A is measured by an ultrasonic interface meter is displayed as an image. FIG. 2A shows a case where the activated sludge in the sedimentation tank 150 is in a good sedimentation state, and the treated water layer 181 and the activated sludge layer 182 are clearly separated. In such a case, as shown in FIG. 2B, the image has a low density portion 181a (a portion corresponding to the treated water layer 181) and a high density portion 182a (a portion corresponding to the activated sludge layer 182). And are displayed in different colors. In FIG. 2B, the horizontal axis is the measurement time axis. Such an image can be displayed using an image display device such as a CRT display device, a liquid crystal display device, or a plasma display device.

  Next, an image obtained by measurement by the ultrasonic interface meter 170 and a state in the sedimentation tank 150 assumed from each image will be described.

3A to 3D are diagrams schematically showing images that can be obtained by measurement using an ultrasonic interface meter. In the image shown in FIG. 3A, the interface 183a between the low density portion 181a (the portion corresponding to the treated water layer 181) and the high density portion 182a (the portion corresponding to the activated sludge layer 182) is clear. It shows how it is. This state is a state in which stable operation is performed. That is, the COD component loaded on the bacteria in the activated sludge is moderate, and as a result, the COD concentration of the treated water is stable in a low state. In the state of the image shown in FIG. 3A, for example, the load on one bacterium (hereinafter, also referred to as “COD-Bact”) is 40 to 60 pg / (copies · day). COD-Bact is obtained by the following formula 1.
Formula 1: (COD-Bact) = (COD concentration of treated water) / [(bacterial count) × 1.49 × 10 ⁵ ]
For example, when the COD concentration of the water to be treated (COD concentration of the water to be treated before being introduced into the aeration tank 110) is 3000 kg / day, the AOB number is 3.00 × 10 ^{5 to} 9.00 × 10 ^5. It is about cells / mL-MLSS, and the total number of bacteria (the number of bacteria having activity) is about 3.36 × 10 ^{10 to} 5.03 × 10 ¹⁰ cells / mL-MLSS. The COD concentration of the treated water (COD concentration of the treated water that has been treated and discharged from the sedimentation tank 150) is about 85 mg / L or less.

If the operation is performed with the image shown in FIG. 3A being obtained, the interface 183a may rise (see FIG. 3B). When the interface 183a rises, the amount of the activated sludge layer 182 is increased, so that the number of bacteria (the sum of the number of bacteria having activity and the one having lost activity) is increasing. Usually, there are many cases where the number of active bacteria is increasing (in an over-aerated state). In the state of the image shown in FIG. 3B, for example, COD-Bact is 30 pg / (copies · day).
Similar to the example of FIG. 3A, for example, when the COD concentration of the water to be treated is 3000 kg / day, the AOB number is 1.00 × 10 ⁷ cells / in the state of the image shown in FIG. It is about mL-MLSS, and the total number of bacteria (the number of active bacteria) is about 6.71 × 10 ¹⁰ cells / mL-MLSS.
In such a situation, basically, adjustment such as reducing activated sludge, reducing oxygen supply amount, increasing supply amount of water to be treated, that is, adjustment for applying a load is performed. A specific adjustment method will be described later in detail.

Even if a load is applied from the state of FIG. 3B, the state of FIG. 3A may not be returned to the state of FIG. 3A. FIG. 3C shows a state where the entire screen is almost the same color. In the state of FIG. 3C, the activated sludge and the treated water are mixed together as a whole, and a single mixed layer 184 is formed. In the state of FIG. 3 (c), it can be seen that the total number of bacteria (the sum of the number of bacteria having activity and the one having lost activity) has increased, but the bacteria having activity against the COD component. It is not possible to grasp from the image whether there are many (that is, in an over-aerated state) or many bacteria that have lost activity (that is, in an overloaded state). For this reason, if the adjustment is not performed in spite of being in an over-aerated state, the COD component is further reduced, and the bacteria having activity lose activity and float. Thereafter, when the over-aerated state is maintained, the bacteria that have lost their activity and are floated are taken out of the system together with the treated water, and as shown in FIG. 3D, the screen display is as shown in FIG. Similar image display is obtained. However, in reality, only the bacteria that have lost their activity and have floated are taken out of the system, and the COD component contained in the treated water is in a high state.
In this way, when the state shown in FIG. 3C is reached, correct adjustment cannot be made only from the measurement result by the ultrasonic interface meter 170, and the quality of the treated water is maintained at a certain level or higher. There are cases where it is not possible.
However, in this embodiment, the bacterial count is measured by the bacterial count measuring unit 120. Therefore, even in the case of the state of FIG. 3C, it is possible to reliably grasp whether the state is an over-aeration state or an overload state. As a result, it is possible to perform correct adjustment based on the measurement result by the bacteria count measurement unit 120.

  Then, the processing method of the to-be-treated water which concerns on this embodiment is demonstrated. Below, the processing method of the to-be-processed water which does not use the processing apparatus 100 mentioned above is demonstrated first, and the processing method of the to-be-processed water using the processing apparatus 100 mentioned above is demonstrated after that.

  First, activated sludge containing bacteria capable of decomposing COD components is accommodated in the aeration tank 110. This activated sludge contains necessary bacteria such as ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB), phenol degrading bacteria, thiocyan degrading bacteria, and the like.

  Moreover, the to-be-processed water containing a COD component is prepared. As the water to be treated, for example, coke oven wastewater such as condensed water generated by cooling exhaust gas discharged when coke is produced from coal, scrubber wastewater after being treated with a scrubber or the like can be used. In addition, coke oven drainage is also called a gas liquid or a safe water. In addition, the COD density | concentration of to-be-processed water is measured at any time.

  Next, water to be treated is introduced into the aeration tank 110 to biologically treat the water to be treated. Specifically, the water to be treated is introduced into the aeration tank 110 and stirred to mix the activated sludge and the water to be treated, and the organic matter in the water to be treated is absorbed and decomposed by the bacteria in the activated sludge. Thereby, the COD density | concentration of to-be-processed water is reduced. At this time, by supplying oxygen from the oxygen supply unit 130 to the activated sludge, absorption and decomposition of organic substances can be promoted. The supply amount of oxygen is determined based on the measurement result by the ultrasonic interface meter 170, the number of bacteria measured by the bacteria count measurement unit 120, the oxygen concentration in the activated sludge measured by the oxygen concentration measurement unit 131, and the like. It can be controlled by the density controller 132.

  Next, a mixture of activated sludge with reduced COD components in the aeration tank 110 and treated water (that is, treated water) is supplied to the precipitation tank 150.

  Next, in the sedimentation tank 150, the mixture of activated sludge and treated water is separated. Specifically, in the sedimentation tank 150, the supernatant liquid flows down as treated water toward the next stage of treatment, and the precipitated sludge is discharged from the bottom as drawn sludge.

  The extracted sludge discharged from the sedimentation tank 150 by the above process is, for example, partly returned to the aeration tank 110 or its supply part as return sludge, and the remainder is discharged out of the system as surplus sludge. At this time, the amount of activated sludge stored in the aeration tank 110, that is, the number of bacteria can be adjusted by the amount of returned sludge. The amount of returned sludge can be controlled by the sludge amount control unit 160 based on the measurement result by the ultrasonic interface meter 170, the number of bacteria measured by the bacteria number measurement unit 120, and the like.

  By the above steps, treated water with reduced COD components can be generated from the treated water. In addition, the COD density | concentration of treated water is measured at any time. However, if the above process is continued, the COD component may not be appropriately reduced due to various factors. Therefore, in the present embodiment, the following steps are performed to control the COD component to be appropriately reduced.

  FIG. 4 is a flowchart showing an operation condition adjustment process A according to an embodiment of the present invention. The operating condition adjustment process A indicates an operation performed by an operator. In the ultrasonic interface meter 170, measurement is continuously performed, and an image based on the measurement result is displayed in real time on the image display device.

  In the operating condition adjustment process A, first, based on the image obtained from the measurement result by the ultrasonic interface meter 170, the interface 183 between the treated water layer 181 and the activated sludge layer 182 in the sedimentation tank 150 (FIG. 2 (a), It is determined whether or not (see FIG. 2B) is within an appropriate range (step S1). Specifically, it is determined by observing whether the position of the interface (interface height) is rising or observing the density distribution. If the image of the interface 183a is referred to and the interface 183 is determined to be within the appropriate range, the process returns to step S1. On the other hand, when it is determined that the interface 183 is not within the appropriate range, analysis of the number of bacteria is started (for example, sampling from the aeration tank 110 and requesting the analysis of the number of bacteria to an external organization or the like) and the ultrasonic method Based on the measurement result by the interface meter 170, the operating conditions of the aeration tank 110 are adjusted (step S3). The analysis of the number of bacteria may be a measurement of only the number of ammonia-oxidizing bacteria (AOB) or may be a measurement of only the number of total bacteria (authentic bacteria), and the number of ammonia-oxidizing bacteria (AOB) It may be both the number of bacteria (eubacteria). In addition, the number of bacteria such as nitrite oxidizing bacteria (NOB), phenol degrading bacteria, thiocyan degrading bacteria, etc. may be measured. As a method for measuring the number of bacteria such as nitrite-oxidizing bacteria (NOB), phenol-degrading bacteria, and thiocyan-degrading bacteria, a conventionally known method (for example, see Japanese Patent No. 4672816) can be used. Detailed description is omitted.

  After step S3, it is determined whether the interface 183 between the treated water layer 181 and the activated sludge layer 182 has returned to an appropriate range (step S5). If it is determined that the value is within the proper range, the process returns to step S1. If it does not return to the proper range, the adjustment of the operating conditions of the aeration tank 110 is continued until the result of the analysis of the number of bacteria is obtained, and if it is determined that it has returned to the proper range, the process returns to step S1. On the other hand, when the result of the analysis of the number of bacteria started in step S3 is obtained without returning to the proper range (step S5: NO), the operating condition is based on the result of analysis of the obtained number of bacteria. Is adjusted (step S7). Then, it returns to step S1.

  In the embodiment described above, the case where the number of bacteria is analyzed only when the interface height is not within the appropriate range has been described. However, the present invention is not limited to this example, and the interface height is within the appropriate range. In addition, the number of bacteria may be analyzed every certain period (for example, every month). In this case, the operating conditions can be adjusted based on the obtained number of bacteria.

  In the foregoing, the method for treating water to be treated without using the treatment apparatus 100 (the method for treating water to be treated performed by an operator) has been described. Next, the processing method of the to-be-processed water using the processing apparatus 100 mentioned above is demonstrated.

  FIG. 5 is a flowchart showing an operation condition adjustment process executed in the control unit. In the present embodiment, the case where the oxygen concentration control unit 132 and the sludge amount control unit 160 are configured by one control unit will be described. That is, in this embodiment, the oxygen concentration control unit 132 and the sludge amount control unit 160 correspond to the control unit of the present invention.

  Data related to the number of bacteria is transmitted to the control unit from the bacteria count measurement unit 120 periodically (for example, once a week). In addition, data related to the measurement result is transmitted continuously (for example, every several seconds) from the ultrasonic interface meter 170 to the control unit.

In the operating condition adjustment process, first, the control unit determines whether or not data relating to the number of bacteria has been received from the bacteria count measurement unit 120 (step S10). When it is determined that the data related to the number of bacteria has been received, the control unit calculates the COD-Bact value based on the COD concentration of the water to be treated that is measured as needed and the data related to the received number of bacteria. It is determined whether or not the COD-Bact value is within a predetermined range (step S12). If it is determined that the COD-Bact value is within the predetermined range, the process returns to step S10. On the other hand, when determining that the COD-Bact value is not within the predetermined range, the control unit adjusts the operating condition of the aeration tank 110 based on the COD-Bact value (step S14). Specifically, when it is determined that the number of bacteria is larger than the preset upper limit (over-aeration state), the amount of oxygen supplied from the oxygen supply unit 130 to the activated sludge is reduced, or sedimentation is performed. Control is performed to increase the amount of excess sludge withdrawn from the tank 150 so as to shorten the SRT or ASRT.
In step S12, it is also determined whether the COD-Bact value is within the predetermined range and the AOB number is within the predetermined range, and the COD-Bact value is within the predetermined range, and the AOB number Is within the predetermined range, the process is returned to step S10. If any of them is not within the predetermined range, the operating condition of the aeration tank 110 is changed to the COD-Bact value and / or the AOB number in step S14. It is good also as adjusting based on.

  If it is determined in step S10 that data relating to the number of bacteria has not been received, it is determined whether or not a predetermined period has elapsed since the data relating to the number of bacteria was last received (step S16). If it is determined that a predetermined period (for example, 2 days) has not elapsed since the last data reception regarding the number of bacteria was received, the process returns to step S10. This is based on the measurement result from the ultrasonic interface meter 170 in order to prioritize the adjustment of the operation based on the number of bacteria when the predetermined period has not elapsed since the last reception of the data on the number of bacteria. This is because the operation is not adjusted based on the data.

  On the other hand, when it is determined in step S16 that the predetermined period has elapsed since the last data on the number of bacteria was received, the control unit relates to the measurement result continuously received from the ultrasonic interface meter 170. Based on the data, it is determined whether or not the interface 183 (see FIG. 2A) between the treated water layer 181 and the activated sludge layer 182 in the sedimentation tank 150 tends to increase (step S18). Specifically, the control unit determines whether or not the interface 183 has an upward tendency as compared with the data related to the measurement result received previously. When determining that the interface 183 does not tend to increase, the control unit returns the process to step S10. On the other hand, when it is determined that the interface 183 tends to rise, the control unit adjusts the operating condition of the aeration tank 110 (step S20). A specific adjustment method is the same as that in step S14.

  As described above, according to the method for treating water to be treated according to the present embodiment, it is possible to adjust the operating conditions in real time based on the data relating to the measurement result continuously received from the ultrasonic interface meter 170. It is possible, and more reliable adjustment of the operating conditions can be performed based on the data related to the number of bacteria periodically received from the bacteria count measuring unit 120. Thereby, it becomes possible to maintain the quality of treated water more reliably than a certain level. Moreover, since the measurement result by the ultrasonic interface meter is used, the frequency of expensive bacteria count measurement can be reduced, and the running cost can be reduced.

  In the above-described embodiment, the case has been described in which the operating conditions of the aeration tank 110 are adjusted based on the temporal change in the interface height. However, the present invention is not limited to this example as long as the operating condition of the biological treatment tank is adjusted based on the measurement result by the ultrasonic interface meter (measurement result of the state in the sedimentation tank). For example, after dividing an image obtained by measurement with an ultrasonic interface meter into a plurality of regions, the density in each region is digitized, a predetermined calculation is performed using these values, and according to the calculation result, It is good also as adjusting the operating condition of a biological treatment tank.

  In the embodiment described above, if the predetermined period has not elapsed since the last bacterial count, the operation is adjusted based on the bacterial count, and the predetermined period has elapsed since the last bacterial count was measured. In this case, the case where the operation is adjusted based on the measurement result by the ultrasonic interface meter 170 has been described. However, the present invention is not limited to this example as long as the operating conditions of the biological treatment tank are adjusted based on the measurement result by the ultrasonic interface meter and the measurement result of the number of bacteria.

  In the above-described embodiment, the case where the oxygen concentration control unit 132 and the sludge amount control unit 160 correspond to the control unit of the present invention has been described. However, the control unit of the present invention is not limited to this example as long as the operating condition of the biological treatment tank is adjusted based on the measurement result by the ultrasonic interface meter and the measurement result of the number of bacteria. For example, the amount of water to be treated introduced into the biological treatment tank may be adjusted, or new activated sludge may be added for adjustment.

  In the above-described embodiment, the case where the oxygen concentration control unit 132 and the sludge amount control unit 160 are configured by one control unit has been described, but the present invention is not limited to this example. For example, the oxygen concentration control unit 132 and the sludge amount control unit 160 are configured as separate control units, and the overall controller that controls these control units in an integrated manner is provided as the control unit of the present invention. The structure which adjusts the operating condition of a biological treatment tank may be sufficient. In this case, the oxygen concentration control unit 132 and the sludge amount control unit 160 adjust the oxygen supply amount and the return sludge amount under the control of the overall controller.

  In the above, the processing method of the to-be-processed water using the processing apparatus 100 was demonstrated. However, the method for treating water to be treated according to the present invention is not limited to the example using the treatment apparatus 100. Moreover, the operation (process) described above may be performed by an apparatus, or a part of the operation may be performed by an operator or the like.

  In the above-described embodiment, the case where the interface meter of the present invention is an ultrasonic type has been described. However, the interface meter of the present invention is not limited to this example as long as it can measure the state in the settling tank (for example, image the sludge concentration distribution in the settling tank). A float type, radar type, pressure type, souding type, or strain type interface meter may be used.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described example, and it is possible to make design changes as appropriate within a range that satisfies the configuration of the present invention.

100 treatment device 110 aeration tank (biological treatment tank)
120 Bacterial count measurement unit 130 Oxygen supply unit 131 Oxygen concentration measurement unit 132 Oxygen concentration control unit 150 Sedimentation tank 160 Sludge amount control unit 170 Ultrasonic interface meter 181 Treatment water layer 182 Activated sludge layer 181a Low density part (treatment water layer 181)
182a High density part (part corresponding to activated sludge layer 182)
183a interface

Claims (7)

Introducing a treated water containing a COD component into a biological treatment tank containing activated sludge containing bacteria capable of degrading a COD component, and biologically treating the treated water;
Separating the activated sludge supplied from the biological treatment tank and the treated water in a sedimentation tank provided at a later stage than the biological treatment tank;
A step of continuously measuring the state in the settling tank by an interface meter installed in the settling tank;
Periodically measuring the number of bacteria in the activated sludge stored in the biological treatment tank;
Until the predetermined period has elapsed since the last measurement of the number of bacteria, based on the measurement result of the number of bacteria, adjusting the operating conditions of the biological treatment tank,
After a predetermined period of time has passed since the last measurement of the number of bacteria, the step of adjusting the operating conditions of the biological treatment tank based on the measurement result by the interface meter , Processing method. Introducing a treated water containing a COD component into a biological treatment tank containing activated sludge containing bacteria capable of degrading a COD component, and biologically treating the treated water;
Separating the activated sludge supplied from the biological treatment tank and the treated water in a sedimentation tank provided at a later stage than the biological treatment tank;
A step of measuring the state in the settling tank with an interface meter installed in the settling tank;
Determining whether the measurement result by the interface meter is within an appropriate range; and
When it is determined that the measurement result by the interface meter is not within an appropriate range, the analysis of the number of bacteria in the activated sludge contained in the biological treatment tank is started, and based on the measurement result by the interface meter, Adjusting the operating conditions of the biological treatment tank;
After starting the analysis of the number of bacteria, if the result of analysis of the number of bacteria is obtained while the measurement result by the interface meter does not return within the appropriate range, based on the result of analysis of the number of bacteria obtained And a step of adjusting operating conditions of the biological treatment tank. The step of measuring the number of bacteria in the biological treatment tank is a step of measuring the number of ammonia oxidizing bacteria,
The step of adjusting the operating condition of the biological treatment tank is a step of adjusting the operating condition of the biological treatment tank based on the measurement result by the interface meter and the measurement result of the number of ammonia oxidizing bacteria. The processing method of the to-be-processed water of Claim 1 or 2 . The step of measuring the state in the settling tank includes measuring the interface height between the treated water in the settling tank and the activated sludge,
The process of adjusting the operating condition of the biological treatment tank is a process of adjusting the operating condition of the biological treatment tank based on a change with time of the interface height . The processing method of the to-be-processed water of 1 . The treated water according to any one of claims 1 to 4 , wherein the treated water contains condensed water generated by cooling an exhaust gas discharged when coke is produced from coal. Treatment method of treated water. A biological treatment tank containing activated sludge containing bacteria capable of degrading COD components;
A settling tank for separating activated sludge supplied from the biological treatment tank and treated water to be treated, provided at a stage after the biological treatment tank,
An interfacial meter installed in the settling tank and continuously measuring the state in the settling tank;
A measurement unit for periodically measuring the number of bacteria in the activated sludge accommodated in the biological treatment tank;
Based on the measurement result by the interface meter and the measurement result of the number of bacteria, a control unit that performs control to adjust the operating conditions of the biological treatment tank ,
The controller is
Until the predetermined period has passed since the last measurement of the number of bacteria, based on the measurement result of the number of bacteria, adjust the operating conditions of the biological treatment tank,
Finally after a predetermined period to measure the bacterial count has elapsed, based on the measurement result by the interface meter, the processing unit of the for-treatment water which is characterized that you adjust the operating conditions of the biological treatment tank. A biological treatment tank containing activated sludge containing bacteria capable of degrading COD components;
A settling tank for separating activated sludge supplied from the biological treatment tank and treated water to be treated, provided at a stage after the biological treatment tank,
An interfacial meter installed in the settling tank and measuring the state in the settling tank;
A measuring unit for measuring the number of bacteria in the activated sludge accommodated in the biological treatment tank;
Based on the measurement result by the interface meter and the measurement result of the number of bacteria, a control unit that performs control to adjust the operating conditions of the biological treatment tank,
The controller is
Determine whether the measurement result by the interface meter is within an appropriate range,
When it is determined that the measurement result by the interface meter is not within an appropriate range, the analysis of the number of bacteria in the activated sludge contained in the biological treatment tank is started, and based on the measurement result by the interface meter, Adjust the operating conditions of the biological treatment tank,
After starting the analysis of the number of bacteria, if the result of analysis of the number of bacteria is obtained while the measurement result by the interface meter does not return within the appropriate range, based on the result of analysis of the number of bacteria obtained The processing apparatus of the to-be-processed water characterized by adjusting the operating condition of the said biological treatment tank.

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