JPH0736281Y2 - Respiratory rate measuring device - Google Patents

Description

[Detailed description of the device] A. Industrial field of application The present invention relates to a respiration rate measuring device used for controlling activated sludge process, and particularly determines whether or not the inside of a measuring tank needs to be cleaned after measurement. The present invention relates to a respiratory rate measuring device which is adapted to carry out a cleaning step.

B. Outline of the Invention The present invention is an apparatus for measuring the respiration rate of activated sludge by introducing an activated sludge liquid into the measurement tank and aerating with air and measuring the dissolved oxygen concentration. A diluent introducing pipe for replacing the inside of the tank with a diluent after measuring the velocity, and a check water introducing pipe for measuring the respiration rate of the activated sludge in the check water diluted with the diluent, Unnecessary cleaning process by arranging a cleaning liquid introducing pipe for introducing the cleaning liquid into the measuring tank after determining whether or not to clean the measuring tank based on the respiration rate of the activated sludge by the test water for checking By distinguishing between them, the injection rate of chemicals required for cleaning is significantly reduced, and the influence of this chemical on the activated sludge process is suppressed.

C. Conventional technology As a method of treating organic wastewater, there is a method of using activated sludge. In this method, wastewater is allowed to flow into an aeration tank, where it is mixed with activated sludge and air is supplied to treat the wastewater, and the mixed solution is led to a final settling tank for solid-liquid separation, and then discharged as supernatant water. Is the way.

The respiration rate of activated sludge (hereinafter referred to as "r _r ") is used to evaluate the activity of activated sludge in such activated sludge process. Conventionally, the automatic measurement of r _r has been performed as follows using the device shown in FIG. In FIG. 2, 1 ₁ and 1 ₂ are sample inlets and sample outlets, 2 is a measuring tank, and a tube 3 forming a water passage is connected to the inlet and outlet sides of the measuring tank 2. V ₁ and V ₂ are pinch valves, and the tube 3 is brought into a pinch state and a released state by injecting and exhausting air from the air injecting ports 4 ₁ and 4 ₂ , whereby the opening / closing operation is performed. Reference numeral 5 is a DO electrode as a dissolved oxygen (hereinafter referred to as “DO”) concentration detection unit, 6 is a stirrer, and 7 is an air inlet.

First, air is introduced from the air inlet 7 to form an air lift, and the activated sludge liquid in the aeration tank is introduced into the measuring tank 2. At this time, the pinch valves V ₁ and V ₂ are opened. Next, the pinch valve V ₁ is closed to aerate the inside of the measuring tank 2 to increase the DO concentration to a certain constant value, for example, 5 mg / l. When the DO concentration rises to the set value, the aeration is stopped, the pinch valve V ₂ is closed, and stirring is started. The DO concentration decreases as oxygen is consumed by activated sludge (aerobic microorganisms), and r _r is calculated from the rate of decrease.

D. Problem to be Solved by the Invention In the above-mentioned device, sludge adheres to the detectors in the measurement tank 2 such as the DO electrode 5 and the agitator 6 or the auxiliary equipment such as the agitator 6, and proliferates, causing the measurement error. May be For example, that the sludge concentration apparently test water was increased, a result r _r value becomes the actual height eyes than r _r value of test water, the measurement accuracy of r _r decreases.

In order to prevent this, the inside of the measuring tank 2 is washed and sterilized with a chemical such as sodium hypochlorite. However, since the optimum injection rate of chemicals changes depending on the concentration of activated sludge in test water, the concentration of ammolytic nitrogen, pH, etc., it is often the case that injection is excessive. Further, since the activated sludge liquid is contained in the measuring tank 2 after washing, the liquid in the measuring tank 2 was returned to the aeration tank in order to process this. For this reason, the amount of chemicals used increases and the chemicals are drained to the aeration tank, so that the influence of chemicals on the process has been a problem.

The present invention aims to solve these problems.

E. Means for Solving the Problems The present invention is an apparatus for measuring the respiration rate of activated sludge by introducing an activated sludge liquid into a measuring tank and aerating with air and measuring dissolved oxygen concentration. In the tank, a diluting liquid introduction pipe for replacing the inside of the tank with a diluting liquid after the measurement of the respiration rate, and a check test water for measuring the respiration rate of the activated sludge in the check test water diluted by the diluting solution An introduction pipe and a cleaning liquid introduction pipe for introducing a cleaning liquid into the measurement tank after determining whether or not to wash the inside of the measurement tank with reference to the respiration rate of the activated sludge by the test water for checking are provided. .

F. Action After the step of measuring the respiration rate of the activated sludge liquid, the inside of the measuring tank is replaced with a diluting solution, and then a test water for checking is introduced to measure the respiration rate of the adhering activated sludge. Then, based on this measured value, it is determined whether or not the cleaning step is necessary, and if necessary, the cleaning step is performed, and if not, the cleaning step is not performed. The washing step is performed by replacing the inside of the measuring tank with a diluting solution and then introducing the washing solution. Note that the cleaning step may be performed after the respiratory rate measuring step without performing the step of introducing the check water for checking.

G. Embodiment FIG. 1 is a view showing an embodiment of the present invention, in which the same symbols as in FIG. 2 indicate the same parts. First will be described a basic configuration, 1 ₁ the sample inlet, 1 ₂ Sample outlet 2
Is a measuring tank, and a tube 3 forming a water passage is connected to the inlet and outlet sides of the measuring tank 2. V ₁ and V ₂ are pinch valves, and the tube 3 is brought into a pinch state and a released state by injecting and exhausting air from the air injecting ports 4 ₁ and 4 ₂ , whereby the opening / closing operation is performed. Reference numeral 5 is a DO electrode as a dissolved oxygen concentration detector, 6 is a stirrer, and 7 is an air inlet.

In this embodiment, in addition to the above structure, the following mechanism is added. That is, 8 is a diluent introducing pipe for introducing the diluent into the measuring tank 2, V ₃ is a valve, and 9 is checking water for checking, for example, checking water for introducing artificial sewage into the measuring tank 2. A pipe, 10 is a cleaning liquid introducing pipe for introducing a cleaning liquid.

The operation of this embodiment will be described below. First, as a basic operation, air is introduced from the air inlet 7 to form an air lift, and the pinch valves V ₁ and V ₂ are opened to move the activated sludge liquid in the aeration tank from the sample inlet ₁₁ to the measuring tank. Install in 2

Next, after closing the pinch valve V ₁ , air is sent from the air inlet 7 to aerate the inside of the measuring tank 2 to raise the DO concentration to a certain value. When the DO concentration rises, aeration is stopped, the pinch valve V ₂ is closed, and the stirrer 6 is driven to start stirring. Then, the DO concentration decreases with the oxygen consumption by the activated sludge, and the respiration rate r _r is calculated from the decrease rate.

After measuring the r _r sample of the aeration tank in this manner, the activated sludge liquid from the aeration tank in the measuring vessel 2 r _r
After measuring, the pinch valve V ₂ is opened and the valve V ₃ is opened, and tap water (or the supernatant water of the final settling tank) as a diluting liquid is introduced into the measuring tank through the diluting liquid introducing pipe 8. The pinch valves V ₁ and V ₂ are closed when measuring r _{r of the} activated sludge liquid. Then, when the activated sludge liquid in the measuring tank 2 is almost replaced with tap water, the valve V ₃ is closed.

Next, artificial sewage is introduced into the measurement tank 2 through the check water introduction pipe 9, and then aerated until the DO concentration in the measurement tank 2 becomes a certain value or more. When the DO concentration reaches the target value, the aeration is stopped, the pinch valve V ₂ is closed, and the stirring by the stirrer 6 is started. The DO concentration decreases due to the oxygen consumption of the activated sludge adhering to the measuring tank 2, and the r _r value is calculated from the decrease curve. Since this r _r value corresponds to the amount of activated sludge in the measuring tank 2, if the r _r value is less than the set value, it does not affect the measurement of r _r for the activated sludge liquid in the aeration tank. As a result, the cleaning process is not performed.

If the r _r value is greater than or equal to the set value, the washing process is carried out because it affects the r _r measurement of the activated sludge liquid. In this case, first open the pinch valve V ₂ and the valve V ₃ ,
By introducing tap water, the artificial sewage in the measurement tank 2 is discharged to the aeration tank and replaced with tap water. Next, a cleaning solution such as sodium hypochlorite is introduced into the measuring tank 2 through the cleaning solution introducing pipe 10. After a certain period of time has passed since the cleaning liquid was added, the pinch valve V ₂ is opened, and then the valve V ₃ is opened to inject tap water until the cleaning liquid in the measuring tank 2 is exhausted. When drainage of the washing water is completed, the valve V ₃ is closed and the washing process is completed.
There are two purposes for introducing the diluent into the measuring tank 2. The first is the function of discharging the sample liquid introduced from the aeration tank from the measurement tank 2, and the second is the function of diluting the check test water introduced. The diluting solution used here has no problem as long as the concentration of a substance that is a substrate for microorganisms such as nutrient salts or organic matter is a level that can be ignored as a respiration rate. Is available.

The artificial substrate prepared in advance a predetermined concentration in a diluent, for example, since standard nutrient solution is obtained for the microorganism by injecting Anmoa Toka such as glucose, respiration rate r _r The standard nutrient solution by the method described above as the subject Is measured and whether the cleaning of the measuring tank 2 is necessary or not is determined from the result. That is, the inner wall of the measuring tank 2 or the DO electrode 5
If a certain amount or more of microorganisms adhere to the surface of the, the respiration rate increases in proportion to the amount of the attached microorganisms, and the cleaning process is performed when the respiration rate becomes so large that it cannot be ignored.

Therefore, one of the features of the present invention is that the diluting liquid used in this example is mainly used to determine whether or not the cleaning step in the measuring tank 2 is necessary.

The estimation of the amount of adhered sludge and the cleaning process may be carried out every time r _r measurement of the activated sludge liquid is completed, or
It may be performed after the measurement of r _r is repeated several times.

In the present invention, the step of estimating the amount of attached sludge using artificial sewage may be omitted.

Further, in the present invention, a discharge pipe 11 equipped with a valve V ₄ for discharging the liquid in the measuring tank 2 to the treated water tank such as an oxygen mixing tank is provided, and the cleaning liquid in the measuring tank 2 is discharged to the treated water tank. You may do it.

H. Effect of the Invention According to the present invention described above, since the measuring tank is filled with a diluting liquid such as tap water at the time of cleaning, the cleaning liquid is more difficult than the conventional case where the activated sludge liquid is filled. The injection rate of (chemicals) is remarkably low. The reason is that the amount of chemicals used such as sodium hypochlorite consumed by activated sludge and ammonia nitrogen existing in the activated sludge liquid is lost. Therefore, the influence of chemicals on the activated sludge process can be suppressed. Further, since the cleaning liquid is replaced with a diluting liquid such as tap water, the cleaning liquid can be directly drained to a treated water tank such as a chlorine mixing tank without returning to the aeration tank, and in this case, the above influence is eliminated.

In particular, since r _r is measured by using a check test water in which an artificial substrate is added to a diluent such as tap water or the supernatant of the final sedimentation basin, the amount of activated sludge adhering to the measurement tank can be estimated. . Therefore, based on the result, it is judged whether or not the cleaning step should be performed, and if the r _r value is low, the cleaning step can be omitted.
The number of washings is reduced, which reduces the amount of chemicals used and reduces the impact on the activated sludge process.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention, and FIG. 2 is a vertical sectional side view showing a conventional example. 1 ₁ …… Inspection water inlet, 1 ₂ …… Water outlet, 2 …… Measuring tank,
5 ...... dissolved oxygen electrode, 6 ...... stirrer, 8 ...... diluent inlet tube, 9 ...... checking test water inlet pipe, 10 ...... washing liquid inlet pipe, V _1, V ₂ ...... pinch valve, V _3, V ₄ …… Valve.

Claims (1)

[Scope of utility model registration request] 1. An apparatus for measuring the respiration rate of activated sludge by introducing an activated sludge liquid into a measuring tank and performing an aeration operation by air and a dissolved oxygen concentration measuring operation. Diluting liquid introducing pipe for replacing the inside of the tank with diluting liquid, checking water introducing pipe for measuring the respiration rate of activated sludge in the checking water diluted with the diluting liquid, and the checking water for checking The respiratory rate measuring device is characterized in that a cleaning liquid introducing pipe for introducing the cleaning liquid into the measuring tank after deciding whether or not to wash the inside of the measuring tank is provided on the basis of the respiration rate of the activated sludge.