JPS60161797A - Ozone injection control of water treatment plant - Google Patents

Abstract

PURPOSE:To accurately perform the correction of an O3-injection ratio when a certain disturbance factor is generated, by storing various factors resulting in the disturbance of an O3-treatment process and the correction value of the O3-injection ratio corresponding thereto and enabling the correction of a value according to necessity. CONSTITUTION:Raw water is once stored in a tank 1 and introduced into an O3-reaction tank 3 through a flow meter 2 and receives O3-treatment by O3-containing gas supplied through an injection part 4 while treated water is sent to a storage tank 5. For example, when a worker 8 receives communication such that the discharge of a dam was performed at the upstream of a river where raw water is taken, the appearance of the change in the water quality of raw water resulting in disturbance is cleared from the past examples after a certain flow-down time and the correction value C of an O3- injection ratio corresponding thereto is also stored. The worker 8 inputs the value C through an output input apparatus 9 on the basis of predetermined algorism and alters an actual O3-injection ratio CM. The ratio CM calculated by a calculator 10 is inputted to a ratio operator 11 and the O3-injection ratio is converted to an injection amount corresponding to the raw water flow amount value measured by the flow meter 2 to control an O3-generator 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ozone injection control method for controlling the amount of ozone injection in a water treatment facility where ozone is injected.

[Experimental technology]

In water treatment processes such as water supply, medium water supply, industrial water supply, high-level treatment of sewage, and industrial wastewater treatment, sterilization, disinfection, inactivation of viruses, decomposition of organic matter, oxidation of reduced ions, decolorization, deodorization, decontamination, Ozone is injected to improve microbial decomposition or activated carbon adsorption by modifying organic matter, and to promote microfloc formation. If the amount of ozone injected for the purpose of some of the above effects is small, sufficient treatment effects cannot be expected. On the other hand, if the amount of ozone injected is large, it will be uneconomical because more ozone will be injected than necessary, and there will be disadvantages such as an increase in the load on the thinner treatment equipment that will be discontinued because the ozone absorption rate will be lower. . Therefore, the ozone injection rate must always be maintained near the optimum value, but since many factors are involved in the ozone treatment effect, it is actually difficult to express this using a simple mathematical formula.

Some of the injected ozone is consumed! (Ozone consumption)
Factors that influence That is,
These include ozone self-decomposition and volatilization into the atmosphere due to weather conditions such as sunlight and water temperature, and fluctuations in the concentration of ozone-consuming substances contained in raw water. Changes in raw water quality include changes in reduced ion concentration, pollutant organic matter concentration, suspended solids concentration, etc.

Variable factors when raw water is taken from natural water systems such as rivers and lakes include, for example, contamination with sewage and domestic wastewater, self-purification and eutrophication of watershed water systems, and water damage caused by typhoons and torrential rains. This includes muddy contamination and discharge of dam water, which is the source of moldy odors.

The actual state of the ozone injection method in water treatment facilities is determined by plant operators who compare the above conditions with the residual ozone concentration in the treated water or the ozone concentration in the waste gas discharged from the company's ozone reactor to the outside. The appropriate ozone injection rate under what conditions is determined empirically. In this operating method, a skilled operator can skillfully modify the ozone injection rate to maintain it at an appropriate value. However, with this method, there is no clear past experience that says, ``In such a case, it is enough to modify the ozone injection straw.'' Therefore, it is difficult to preserve past cases in a form that can be transmitted. could not.

By the way, there is a concept of setting the ozone injection rate using automatic control such as feedback control. For example, the ozone injection rate is changed so that the residual ozone concentration in treated water or the ozone concentration in waste gas becomes a constant value.

However, since ozone undergoes self-decomposition, even if the same treatment effect is obtained, the residual ozone concentration in the treated water will change due to fluctuations in residence time, or the absorption of ozone into the water will depend on factors such as water temperature. Therefore, even if the treatment effect is the same, the ozone concentration in the waste gas changes, making it difficult to obtain the expected results with shift feedback control.

To summarize the problems of the conventional technology, firstly, it is not always possible to accurately grasp the ozone treatment effect with the conventional direct control such as feedback control using a computer.
Therefore, the reality is that plant operators operate the plant manually without using the control system. Second, with the method in which one operator manually determines the ozone injection rate, past experience is not memorized as a specific value, so another operator may not be able to make use of past examples and repeat the same mistakes. There was a drawback.

C. Summary of the Invention The present invention has been made to improve the drawbacks of the conventional method as described above, and it stores various factors that cause disturbance in the ozone treatment process and correction values for the ozone injection rate corresponding to the degree of disturbance. Since we made it possible to modify the value as needed,
It is an object of the present invention to provide an ozone injection control method that can accurately correct the ozone injection rate when a certain disturbance factor occurs.

In order to achieve the above-mentioned object, the present invention was made as a result of analyzing the ozone treatment process and its disturbance. When using a computer to determine the ozone injection rate in order to maintain a stable ozone treatment effect at a facility, it is necessary to predict the factors that will cause disturbance to the ozone consumption and the ozone injection rate that should be corrected according to the degree of disturbance. The ozone injection rate can be maintained at an optimum level by storing the ozone injection rate inside the computer, allowing the plant operator to judge and select the disturbance factor and its intensity, and correcting the ozone injection rate using the stored value inside the computer. That is.

[Embodiments of the invention]

An ozone injection control method for a water treatment facility will be described below based on an embodiment of the present invention.

Taking the case of a water treatment plant that takes water from a river as an example, events that affect the ozone treatment process can be restored as shown in Table 1 below.

Table 1 shows examples of correction values for the ozone injection rate according to each event and its degree according to the embodiment of the present invention.

The number classification of event i in Table 1 is as follows: 1 to 7 are direct raw water quality indicators, 10 to 22 are factors that contribute to fluctuations in raw water quality, and 61 to 37 are treatments as seen by plant operators. Effects and plant operation convenience, 41-46 are weather conditions, 5
Numbers 1 to 56 indicate direct ozonation properties. The degree of these events is expressed by j, for example, 0: not applicable, 1: small, 2: somewhat small, 3: moderate, 4:
It corresponds to six levels: somewhat large, 5: large. In Table 1, the case of j = 2.4 is omitted, and j
The corrected ozone injection rate η value in the case of = 0.1.45 is shown in numerical value (/l). For example, event 1 = 2
In case of "raw water 7 has high chromaticity", increase the ozone injection rate by 0.2 W/ when j-1, and in case of event i-18 "water intake flow rate from clear water system is high", when j=6 This means reducing the ozone injection rate by 0.15 W/. In addition, in Table 1, for example, i = 7 and 12° or i w 4 and 1
There are some overlapping events such as 0. In this case, usually 1
Since there are many facilities that are not equipped with water quality sensors such as = 1 to 7, it is better to use the ones with 1 = 10 to 22, but if there are duplicates, use the one that is easier to use. The same applies to events 1=51 to 56 indicating the processing effect.

Here, if the correction value of the ozone injection rate corresponding to 10 or so events is expressed as C(1*j'), the correction value ΔC/l of the ozone injection rate corresponding to 1 events is the corresponding value in Table 1. It can be expressed using a table as shown in equation (a).

ΔC=ΣC(irj) ・・・・・・・・・・・・(I
Actually, the basic input CB11/l is given as the value of the base ozone injection rate at the water treatment facility.
The value obtained by adding the above ΔC to the value of CB becomes the actual ozone injection rate cM shift (Equation (2)).

CM depth CB+ΔC (2) An example of an algorithm for determining the ozone injection rate using the equation (2) is shown in FIG. In Figure 1, the values of ΔC and CB should be corrected according to the actual ozone injection rate C.
This is a flow that includes M. In addition, when correcting the value of △C, the injection rate correction c
(1tj) is subtracted from ΔC in advance, and then C(i, j) corresponding to the newly input degree jK is added.

FIG. 2 is a block diagram of an ozone injection control method according to an embodiment of the present invention. In Figure 2, 1 is a raw water storage tank, 2 is a flow meter, 3 is an ozone reaction tank, 4 is an ozone injection part, 5 is a treated water storage tank, 6 is a head space, 7 is an exhaust ozone treatment device, and 8 is a plant 9 is an input/output device such as a CRT, 10 is a process calculator, 11 is a ratio calculator, 12
is an ozone generator.

FIG. 6 is a block diagram of an ozone injection control method according to another embodiment of the present invention. In FIG. 6, 16 is a human power device such as a voice input device, 14 is a computer, 15 is an output device such as a voice output device, and 16 is an ozone injection rate setting device.

Next, the ozone injection control method of the present invention will be explained based on the above embodiment. In Figures 2 and 6, the raw water to be ozonated is stored in the raw water storage tank 1, and then the flow meter 2
The ozone-containing gas is then introduced into an ozone reaction tank 3, where it is vented through an ozone injection section 4 to perform ozone treatment. The ozonated water is then sent to the treated water storage tank 5, while the ozone-containing exhaust gas accumulated in the head space 6 is treated by the exhaust ozone treatment device 7 and then released into the atmosphere.

The operator 8 always pays attention to water quality analysis values in the water treatment process and changes in the external environment. At this time, for example, suppose that the operator 8 receives a message that water has been released from a dam upstream of the river from which raw water is taken. In this case, it has been shown in past cases that a change in the quality of the raw water, which is a disturbance, occurs due to the discharge from the dam after a certain flow time, and the corresponding correction value for the ozone injection rate is also stored. Therefore, in operation 8, it is possible to select the event i that should be the disturbance and its degree j, and to utilize the appropriate ozone injection rate correction value C (i, j) stored inside the computer. That is, the operator 8 changes the actual ozone injection rate C by inputting the ozone injection rate correction value C (IIj) via the input/output device 9 such as a CRT based on the algorithm shown in FIG. The value of C calculated by the process calculator 10 is input to the ratio calculator 11, and the ozone injection rate (wv/
After converting from l) to ozone injection f (kg/hour),
By controlling the discharge voltage or frequency of the ozone generator 12, a predetermined amount of ozone generation (kg/hour) is obtained. The ozone-containing gas generated in step 12 is introduced into the ozone reaction tank 6 through the ozone injection section 4, and ozone treatment of raw water is performed at an appropriate ozone injection rate.

In the configuration example shown in FIG. 2 above, a method of directly controlling the ozone injection rate using the process computer 10 has been described. On the other hand, in the configuration example shown in FIG. 3, the ozone injection rate CM calculated by the algorithm shown in FIG. 1 can be determined off-line. In addition, in FIG. 6, the ozone injection rate commercial obtained by the computer is only used as operational guidance, and the actual ozone injection rate is set manually by the operator.

Regarding the configuration example shown in FIG. 6, an embodiment in which the input device #16 is a voice input device and the output device #15 is a voice output device will be described below. As in the case of FIG. 2, the operator 8 monitors the process while paying attention to water quality analysis values and changes in the external environment.

In this case, the operator 8 responds to the change in the situation by saying, ``What is (A?
), and to what extent (wholesale, what is 0°?). For example, it is determined that "the flow rate of water intake from a highly polluted water system is (4), extremely (B), and large (C)." Suppose that we have made a decision as to "What is (4) and what is (Oo)" at this time.

At this time, the part ``What is the prisoner, what is the (C) J corresponds to event 19 in Table 1, and the part ``To what degree (publication)'' corresponds to the degree j. For example,
1: Slightly, 2: A little, 6: Moderate, 4: Kana, 5
The rule is: extremely. Then, the input device 16 identifies the voice, selects the corresponding i and j, and then outputs the information of C(1, j)! [Output via step 15. The output method from the output device 15 is ``Increase the ozone injection rate by 0.5, etc.'' or ``Increase the ozone injection rate a little bit'' as in the case of the above input. The operator 8 can maintain an appropriate ozone injection rate as in the case of FIG. 2 by appropriately changing the setting value of the ozone injection rate setting device 16 based on the information.

Note that the ozone injection rate correction value C(
i, j) are of a nature that should be modified as necessary by gaining experience, so this parameter change is also
The configuration is such that it can be easily performed using an input/output device such as RT.

〔Effect of the invention〕

As described above, according to the present invention, events that cause disturbance to the ozone treatment process and corresponding changes in the ozone injection rate are stored in the computer as correction values according to the degree of disturbance, and are configured to be used. , even past cases related to events with low occurrence frequency can be saved as concrete numerical values and used for control operations.

This method has the effect of maintaining an appropriate ozone injection rate at all times even when past cases have been forgotten by personnel or when an inexperienced operator manages the ozone treatment process.

Furthermore, by adopting an audio input/output device as the input/output device, you can eliminate the need for keyboard operations such as J, CRT, etc.
It is also effective as operational guidance for man-machine communication in the form of daily conversation.

Further, although the above-described ozone injection control method is described for the case where ozone is used as the chemical to be injected, the same method can be used when using other oxidizing agents, disinfectants, etc.

[Brief explanation of drawings]

FIG. 1 is an algorithm for determining an ozone injection rate according to an embodiment of the present invention, and FIGS. 2 and 3 are block diagrams of an ozone injection control method according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Raw water storage tank, 2... Flow meter, 6... Ozone reaction tank, 4... Ozone injection part, 5... Treated water storage tank, 6... Head space, 7...・Exhaust ozone treatment device, 8...operator, 9...input/output device, 10...process computer, 11...ratio calculator, 12...oscillator, 16... - Input device, 14... Calculator, 15... Output device, 16... Injection rate setting device. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Patent Attorney Sanro Kimura Figure 1 Figure 2 Figure 3 Procedural amendment (voluntary) June 22, 1980 To the Commissioner of the Japan Patent Office 1, Indication of the case Patent Application No. 17130/1982 2, Invention Name Ozone injection control method for water treatment facilities 3, Person making the amendment Representative Hitoshi Katayama Department 4, Agent 6 Contents of the amendment (1) Column 32 of l of the table (part 6) on page 9 on the side of details i The "production amount" described in 2014 will be corrected to "production amount". (2) Specification 11c, page 12, line 8, “(A) Formula 4=2r
(Corrected as Formula 13 J. (3) Corrected as "Ozone injection rate C" in line 6 of page 15 of the specification as "Ozone injection rate CMJ". (4) Corrected as "Ozone injection rate C" in line 6 of page 15 of the specification The value of C is r CMQ
value”. (5) Suppose that 1 in the 16th volume of the specification, lines 12 to 16, was lowered at this time. ” to be deleted. that's all

Claims (2)

[Claims] (1) When determining the ozone injection rate using a computer in order to maintain the stable effect of ozone treatment at water treatment facilities where ozone is injected, it is necessary to The ozone injection rate to be corrected is stored in the computer in advance, and the disturbance factor and its degree are judged and selected by plant operators and personnel, and the ozone injection rate is corrected using the stored value inside the computer. A method for controlling ozone injection in a water treatment facility, characterized by being able to maintain an optimum dioscin injection rate. (2) Ozone injection into a water treatment facility according to claim 1, characterized in that an audio input/output device is added to the computer to facilitate interaction between the operator of the system and the computer. Control method.