JPS6227097A - Living thing inhibitiveness detector in activated sludge method - Google Patents

Abstract

PURPOSE:To obtain a living thing inhibitiveness detector which makes measurement for a relatively long period of time in particular and is suitable for waste water and liquid by constructing the detector in such a manner that the fluctuation of the respiration speed of activated sludge can be measured with lapse of time for a relatively long period of time. CONSTITUTION:An air supply circuit 15 is connected to a batch type aeration tank 11 which can be held at a constant temp. The air flow rate from the circuit 15 is controlled to maintain the specified DO value by monitoring the DO value in the tank 11 in a flow rate control means 18. The above-mentioned air flow rate is detected with lapse of time by detecting means 20, 22. This living thing inhibitiveness detector can judge the living thing inhibitiveness by determining, with lapse of time, the air flow rate ratio necessary for maintaining the constant DO in the aeration tank. Since the longer measurement time can be taken, the true living thing inhibitiveness of the test water for the activated sludge is discriminated regardless of the nature of the test water such as, for example, the gradual increase of decrease of toxicity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides a method for measuring the respiration rate of activated sludge.
The present invention relates to a biological inhibition detection device used to determine whether target wastewater/waste liquid can be treated by the activated sludge method.

(Conventional technology) Whether new wastewater/waste liquid can be treated by activated sludge method or not.
In other words, the presence or absence of biological inhibition is determined based on the total respiration rate of activated sludge in the presence of wastewater/effluent to be measured (hereinafter referred to as test water) and the respiration rate of activated sludge in the absence of test water, so-called endogenous respiration. This is generally done by finding the ratio of speed to speed.

However, conventionally, the devices for measuring each of the above-mentioned respiration rates are
As shown in the figure, K, flask 1 containing test water, activated sludge, etc.
By placing the flask 1 on the magnetic stirrer 2, the inside of the flask 1 can be moved through the stirrer rotor 3.
A dissolved oxygen concentration (hereinafter referred to as DO) electrode 4 with a rubber stopper attached to the opening of the flask 1 is connected to a DO meter 5 so that changes in the DO value can be measured over time. The results could be recorded on a recorder 6.

First, bacterial cells m19 were added to flask 1 using the above device.
(MLS8) Pour oxygen-saturated water and activated sludge into a 2,500.4000tNi/z toner (Ear yo'), and use a DO electrode with a rubber stopper to seal the DO value in flask 1 to prevent air from entering. Measure the change with DO total 5 and 7
output the result to the recorder 6, and record D according to the unit time.
Find the internal respiration rate V from the change in O. Next, oxygen-saturated water, activated sludge, and test water are placed in flask 1, and the total respiration rate Vn is determined by the same procedure as described above.

If VB/VA>1, it is determined that there is no bioinhibitory property and treatment is required. On the other hand, if VB/Vh (1), it is determined that there is bioinhibitory property (processing is not possible).

(Problems to be Solved by the Invention) By the way, in the case of the conventional measuring device described above, since the reduction in DO in the tightly sealed flask 1 is measured, It is difficult to measure the change in inhibitory properties over time because it can only be measured and the absorption rate is determined by the time differentiation of DO in the flask. For this reason, water samples that require a relatively long measurement time to measure changes in inhibitory properties over time, such as those that gradually increase their inhibitory properties against activated sludge, or those that initially show inhibitory properties,
When targeting substances that gradually recover, the above-mentioned measuring device has a problem in that it is difficult to determine true bioinhibitory properties.

The present invention has been made in view of the above-mentioned conventional problems, and is capable of measuring fluctuations in the respiration rate of activated sludge over time over a relatively long period of time. The purpose of this invention is to provide a bioinhibition detection device suitable for measuring wastewater and wastewater.

(Means for Solving the Problems) For this reason, the present invention includes a batch type aeration tank capable of maintaining constant temperature, connects an air supply circuit to the aeration tank, and monitors the DO value in the aeration tank. The present invention is characterized in that a flow rate control means for controlling the air flow rate from the air supply circuit so that the bo value is constant is provided, and a detection means capable of detecting the air flow rate over time is provided.

(Function) In the bioinhibition detection device having the above configuration, for both the comparison liquid A that does not contain the test water and the measurement liquid B that contains the test water,
Determine the air flow rates Q and QB required to maintain a constant DO value in the aeration tank over time, and calculate the air flow ratio QB.
The bioinhibitory properties of the sample water can be determined based on changes over time in the sample water, for example, by checking whether the air flow rate ratio QB/Q is greater than 1 or by looking at its stability over time. become.

The rationale for determining the presence or absence of bioinhibition from the ratio of air flow rates is as follows.

Generally, if the temperature is constant, the DO in a batch type aeration tank is (1
) O d c/d t=KLa (Ca −C) −r r−
0(1)C: DO value in tank (■/1) C8: Saturated DO value (w9/1) KL a: Overall oxygen transfer capacity coefficient (1/Hr) rr:
Oxygen consumption rate of sludge (Cape/Hr-t) Now, DO in the tank
When controlled to be constant, dc/dt=0, and therefore equation (2) holds true.

KL a (Cs −C)=r r−(2) In this case,
The air flow rate sent into the aeration tank is expressed by equation (3).

Q=V Kt,a(Cs-C)=Vrr=13)Q
: Air flow rate (Cape/Hr) V: Aeration tank volume (1) On the other hand, the oxygen consumption rate γr is given by equation (4).

X: MLss in ia (W/l>a',b': constants Therefore, air flow into the aeration tank - [FrQ is given by equation (5).

Comparative liquid A (pure water and activated sludge) without test water
Air flow f to keep the DO value in the aeration tank constant;
Calculate k QA (= b'
An air test is taken to keep the value constant, and when this value is greater than 1, it can be determined that there is no bioinhibition effect, and when this value is less than 1, it can be determined that there is bioinhibition effect.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

FIG. 1 shows the system of the bioinhibition detection device according to the present invention. In the figure, 11 is an aeration tank, which is kept in a constant temperature tank 12 so as to maintain a constant temperature. A piping 14 whose one end is connected to a proar 15 is led into the aeration tank 11, and an aeration pipe 15 is attached to the other end of the piping 14 which is placed inside the aeration tank 11.

A flow rate regulating valve 16 is interposed in the pipe 14, and a DO meter 17 is provided above the aeration tank 11 to detect the DO value of the liquid in the aeration tank 11, which will be described later. Further, the flow rate adjustment valve 16 and the DO meter 17 are connected to the flow rate control device 18.
and are connected by wires 19, 19. Flow control device 18
has a feedback control function to keep the DO value in the aeration tank 11 constant;
Upon receiving the O value multiplication signal, it outputs an opening/closing control signal to the flow rate regulating valve 16.

A flow meter 20 is also interposed in the pipe 14, and its signal is sent to a computing unit 22 via a wiring 21. The computing unit 22 has a function of storing the air flow rate supplied into the aeration tank 11 through the piping 14 over time, and can calculate the air flow rate ratio of the measurement liquid and the comparison liquid over time, which will be described later. In addition, the recorder 23 is connected to the wiring 24.
connected with.

With this configuration, initially, two MLSSs are installed in the aeration tank 11.
,000 to 000 to 000 to 1,000 to 1000 to 1,000 to 1,000 to 1,000 to 1,000 to 1,000,000 to 1,000,000 to 1,000,000 to 1,000,000 to 1,000,000 to 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,0,000,000,0,000,0000,000,000,000,000,00000,00000, compared, comparatively a comparative comparison of a comparative aht. At the same time, the DO meter 17 starts measuring the DO value in the aeration 4111, and the result is input to the flow rate control device 18. The flow control device 18 compares the input result with a set value and outputs a control signal to the flow f adjustment valve 16 in order to keep the DO value in the aeration tank 11 constant. During this time, the flow rate of air fed into the aeration tank 11 is input to the calculator 22 via the flow meter 20, and the result is stored. Note that since the air flow rate α at this time becomes a constant value over time, the measurement is continued as appropriate and then stopped.

Next, mix an appropriate amount of test water in the above comparison liquid to explode the measurement liquid B, and perform the same operation as above to remove the DOVL in the aeration tank j1.
Determine the air flow rate required to maintain a constant value over time. The computing unit 22 calculates the ratio QB/Q people between this result QB and the result Q for the comparison liquid A, and outputs the change over time to the recorder 23.

Then, the air flow rate ratio QB/ after a predetermined period of time has elapsed.
Q When humans are dogs than 1, it is judged that there is no bioinhibitory property, but on the other hand,
If it is determined that there is biological inhibition when the QB/Q ratio is less than 1, it can be determined whether the sample water can be treated by the activated sludge method. Of course, the suitability of the water test can also be determined based on the stability of the change over time in the air flow rate ratio.

(Effects of the Invention) As explained above in detail, the bioinhibition detection device according to the present invention is capable of determining the air flow rate ratio necessary for maintaining the DO in the aeration tank constant over time. Since we have made it possible to judge bioinhibitory properties, we can take a longer measurement time, so regardless of the nature of the sample water, such as gradual increase in toxicity or gradual decrease in toxicity, it is possible to It is effective in determining the true biological inhibition of activated sludge.

[Brief explanation of drawings]

FIG. 1 is a system diagram of the bioinhibitory detection device according to the present invention,
FIG. 2 is a system diagram of a conventional bioinhibitory detection device. 11...Aeration tank 13...Proa 15...Aeration pipe 16...Flow rate adjustment valve 17...DO meter 18...Flow rate control device 20...Flow meter 22...Arithmetic unit 23 ...Recorder patent applicant Toyota Motor Corporation agent
Patent attorney Yumi Sae (and 1 other person) Figure 1 15・Air intake 22・Arithmetic unit 16...:1 Milk volume adjustment volume 23・Record T17...DO correction

Claims (1)

[Claims] (1) A batch type aeration tank capable of maintaining a constant temperature is provided, an air supply circuit is connected to the aeration tank, and the DO value in the aeration tank is monitored so that the DO value is kept constant. 1. A bioinhibition detection device for an activated sludge method, comprising: a flow rate control means for controlling the air flow rate; and a detection means capable of detecting the air flow rate over time.