JP2001079574A - Method for controlling ozone injection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly inject ozone even if the quality of raw water is varied at the time of controlling the ozone injection so that the dissolved ozone concn. of an ozone contact basin is kept constant by measuring the UV absorbance and temp. of the water to be treated and then determining the ozone injection ratio based on a specified expression. SOLUTION: The UV absorbance A and temp. T of ozoneted water are measured by a UV meter UVT and a thermometer WT, and the absorbance A, temp. T and the controlled set valve C of dissolved ozone concn. are inputted to a controller CTRL 1 to determine the set ozone injection ratio D according to the expression D=aA+bT+cC+d. In the expression, a to d express a constant, respectively. Subsequently, the set injected ozone concn. O3CSP is determined based on the ozonated raw water flow rate from an ozonated raw water flowmeter FT1, the injected ozone gas flow rate from an injected ozone gas flowmeter FT2 and the D in a controller CTRL 3, and the injected ozone concn. in an ozone contact basin 4 is controlled to the O3CSP.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ozone / activated carbon treatment in which ultraviolet absorbance (hereinafter referred to as UV), which is widely used as an organic substance index and can be measured on site, is applied to a water quality index for operation management of the ozone / activated carbon treatment. U for process
The present invention relates to an ozone injection control method using a V meter.

[0002]

2. Description of the Related Art In recent years, with the deterioration of water quality of tap water sources, advanced water purification treatments have been introduced in various places. As a typical advanced water purification treatment, there is a combined treatment of ozone treatment and activated carbon treatment (hereinafter referred to as ozone / activated carbon treatment). The main purpose of introducing ozone / activated carbon treatment was that conventional water purification treatments such as improvement of chromaticity, off-flavor, elimination of bacteria and viruses, oxidation of organic substances, trace contaminants and soluble metals, etc. could not be adequately handled. It is a matter of treating substances and providing safe and comfortable tap water.

Therefore, in the ozone / activated carbon treatment, the behavior of the substance to be removed, such as whether the substance to be removed is removed as intended, and whether the treated water quality is stable with respect to fluctuations in the quality of the raw water, is determined. Operation management is required. Furthermore, in the ozone treatment, a reduction in the ozone injection rate within a range that does not impair the removal effect of the removal target substance is required from the viewpoint of reducing operating costs and suppressing ozone treatment by-products such as bromate ions. . (References: Proceedings of the 48th National Water Supply Research Conference, 512-513 (199
7) "Methods for the generation and suppression of bromate ions in ozone treatment") To fulfill these demands, the behavior of the substances to be removed in the ozone / activated carbon treatment process water is monitored in real time, and based on the monitoring results. It is effective means to evaluate the treatment and control ozone injection to reduce the ozone injection rate.

However, in practice, monitoring and control of the ozone / activated carbon treatment process based on directly grasping the behavior of the substance to be removed is hardly performed at present. The reason is that it is difficult to monitor the substance to be removed in real time. Analytical measurement of the substance to be removed is possible, but it is not easy to perform and cannot obtain an analysis result in real time. For this reason, ozone treatment is monitored and controlled on the premise that exhaust ozone concentration and dissolved ozone concentration, which can be measured in real time, are measured, and the treatment status of the substance to be removed is indirectly grasped from these ozone concentration indices. is the current situation. Typical examples of the ozone treatment control method using such an ozone concentration index include an exhaust ozone concentration constant control and a dissolved ozone concentration constant control.

[0005]

The method of monitoring and controlling ozone treatment based on ozone concentration indexes such as exhaust ozone concentration and dissolved ozone concentration does not directly grasp the state of treatment of the substance to be removed. I don't know if the substance is really being treated as intended. In particular, it is impossible to determine whether ozone is excessively injected or insufficiently injected with respect to the substance to be removed in the target raw water. Therefore, with the monitoring control method based on the ozone concentration index, it is difficult to perform ozone treatment at an appropriate ozone injection rate and reduce the ozone injection rate.

At present, when energy saving is required, even in ozone treatment, it is necessary to maintain a desired treatment effect and to reduce the power consumption accompanying ozone production as much as possible. However, the current problem is that the monitoring and control method based on the ozone concentration index cannot be expected to operate the plant on the premise of energy saving.

The present invention has been made in view of the above circumstances, and uses the ultraviolet absorbance, which is an index of a hardly decomposable organic substance, to ascertain the hardly decomposable organic substance to be removed from the ozone / activated carbon treated water. It is another object of the present invention to provide an ozone injection control method for controlling an ozone injection rate by feedforward control and feedback control.

[0008]

According to the present invention, in order to achieve the above-mentioned object, a first aspect of the present invention provides a method for injecting ozone into an ozone-contacting pond, wherein the concentration of dissolved ozone in the ozone-contacting pond is reduced. In the method of controlling the ozone injection rate so as to be constant, after measuring the ultraviolet absorbance and the water temperature of the water to be treated, the ozone injection rate D (mg / L) is calculated by the following formula. (Abs / 50mm), water temperature T (° C) of treated water and dissolved ozone concentration constant control set value C (mg / L)
Is determined by substituting.

D = a.A + b.T + c.C + d where a, b, c, and d are constants. According to a second aspect of the present invention, the ozone injecting process is performed in a feedforward manner by using the ozone injecting rate determined by the formula for determining the ozone injecting rate. It is characterized by controlling.

The third invention is characterized in that the ozone injection rate obtained in the first invention is feedback-corrected using the dissolved ozone concentration at the outlet of the ozone contact pond and the dissolved ozone concentration constant control set value.

According to a fourth aspect of the invention, ozone is injected by feedforward control and feedback control using the ozone injection rate.

A fifth invention is a method for controlling the ozone injection rate so that the ultraviolet ray absorbance of the ozone-treated water becomes constant when the water-to-be-treated is subjected to ozone injection in an ozone contact pond. After measuring the absorbance and water temperature,
Ozone determined by substituting C = 0 as the ultraviolet absorbance A (abs / 50 mm), the water temperature T (° C.) of the water to be treated, and the dissolved ozone concentration constant control set value C (mg / L) in the following formula: The injection rate D (mg / L) is determined by feedback correction using the ozone-treated water UV absorbance and the ozone-treated water UV absorbance constant control set value.

D = a.A + b.T + c.C + d where a, b, c, and d are constants. The sixth invention is characterized in that an upper limit of dissolved ozone concentration is added in the feedback correction.

According to a seventh aspect of the present invention, ozone is injected by feedforward control and feedback control using the ozone injection rate.

An eighth invention is a method for controlling the ozone injection rate such that the consumption of potassium permanganate (KMnO ₄ ) in the ozone-treated water becomes constant when the water to be treated is subjected to ozone injection in an ozone contact pond. In the above, after measuring the ultraviolet absorbance and the water temperature of the water to be treated, the ultraviolet absorbance A (abs / 50 mm) of the water to be treated, the water temperature T (° C.) and the dissolved ozone concentration constant control set value C are calculated by the following equations. (Mg / L) C = 0
Ozone injection rate D determined by substituting (mg / L), characterized in that to determine the feedback correction using the ozonated water KMnO ₄ consumption estimate and the KMnO ₄ consumption constant control setpoint is there.

D = a.A + b.T + c.C + d, where a, b, c and d are constants. The ninth invention is directed to the potassium permanganate (KMnO ₄ )
The estimated consumption value is obtained by using the following KMnO ₄ consumption estimation formula KM.

KM = a · A ₂ + b · {1- (A ₂ / A ₁ )} + c, where A ₁ : UV absorbance of water to be treated, A ₂ : UV absorbance of ozone treated water, a, b, c: constants tenth invention, and the KMnO ₄ consumption estimation equation, by using the real-time measurable treated water ultraviolet absorbance and ozone treated water UV absorbance, and wherein estimating the ozonated water KMnO ₄ consumption in real time Is what you do.

The eleventh invention is directed to the ozone-treated water KMnO.
_{(4) The method is characterized in that the} consumption is grasped in real time as an estimated value, and the estimated value is used as a control index for ozone injection.

The twelfth invention is characterized in that an upper limit setting of the concentration of ozone-treated water-soluble ozone is added in the feedback correction.

A thirteenth invention is characterized in that ozone is injected by feedforward control and feedback control using the ozone injection rate.

According to a fourteenth aspect, in the method for controlling the ozone injection rate so that the trihalomethane forming ability (THMFP) of the ozonized water becomes constant when the water to be treated is subjected to the ozone injection treatment in the ozone contact pond. After measuring the UV absorbance and the water temperature of the treated water, the UV absorbance A (abs / 50 mm) of the treated water, the water temperature T (° C.) and the dissolved ozone concentration constant control set value C (mg / L) are calculated by the following formulas. ), The ozone injection rate D (mg / L) determined by substituting C = 0 is determined by feedback correction using the estimated value of the ozone-treated water THMFP and the THMFP constant control set value. .

D = aA + bT + cC + d where a, b, c, and d are constants. The fifteenth aspect of the present invention relates to
It is characterized by using the following THMFP estimation equation TH.

TH = a · A + b · T + c where A: UV absorbance of ozonized water, T: water temperature of ozonated water, a, b, c: constants. The sixteenth aspect of the invention is based on the THMFP estimation formula and real-time measurement. Ozone treated water using UV absorbance, water temperature,
The ozone-treated water THMFP is estimated in real time.

The seventeenth invention is directed to the ozone-treated water THMF.
P is grasped in real time as an estimated value, and this estimated value is used as a control index for ozone injection.

An eighteenth aspect of the present invention is characterized in that an upper limit setting of the concentration of ozone-treated water-soluble ozone is added in the feedback correction.

The nineteenth invention is characterized in that ozone is injected by feedforward control and feedback control using the ozone injection rate.

According to a twentieth aspect of the present invention, there is provided a method for controlling the ozone injection rate so that the ultraviolet absorption of the activated carbon treated water becomes constant when the treated water is subjected to the ozone injection in the ozone contact pond. After measuring the absorbance and water temperature,
Ozone determined by substituting C = 0 as the ultraviolet absorbance A (abs / 50 mm), the water temperature T (° C.) of the water to be treated, and the dissolved ozone concentration constant control set value C (mg / L) in the following formula: The injection rate D (mg / L) is determined by feedback correction using the ultraviolet ray absorbance of the activated carbon treated water and the ultraviolet ray absorbance constant control set value.

D = a.A + b.T + c.C + d where a, b, c, and d are constants. The twenty-first invention is characterized in that an upper limit setting of the ozone concentration in the aqueous solution of ozone treatment is added in the feedback correction. It is.

A twenty-second invention is characterized in that ozone is injected by feedforward control and feedback control using the ozone injection rate.

A twenty-third aspect of the present invention is a method for controlling the ozone injection rate so that the consumption of potassium permanganate (KMnO ₄ ) of the activated carbon treated water becomes constant when the water to be treated is subjected to ozone injection in an ozone contact pond. In the above, after measuring the ultraviolet absorbance and the water temperature of the water to be treated, the ultraviolet absorbance A (abs / 50 mm) of the water to be treated, the water temperature T (° C.) and the dissolved ozone concentration constant control set value C are calculated by the following equations. (Mg / L) as C =
Ozone injection rate was determined by substituting D (mg / L) 0, which is characterized by determining at the feedback correction using the activated carbon treated water KMnO ₄ consumption estimate and the KMnO ₄ consumption constant control setpoint It is.

D = a · A + b · T + c · C + d where a, b, c and d are constants. In the twenty-fourth invention, the above-mentioned estimated value of the KMnO ₄ consumption of the activated carbon treated water is calculated by the following equation for estimating the KMnO ₄ consumption of the activated carbon treated water. KM1
It is characterized by having been obtained by using.

KM1 = a · A1 + b where A1: UV absorbance of activated carbon treated water, a, b: constant The twenty-fifth invention is based on the above equation for estimating KMnO ₄ consumption of activated carbon treated water and the ultraviolet ray of activated carbon treated water which can be measured in real time. It is characterized in that the consumption of activated carbon-treated water KMnO ₄ is estimated in real time using the absorbance.

The twenty-sixth invention is directed to the activated carbon treated water KMnO.
_{(4) The method is characterized in that the} consumption is grasped in real time as an estimated value, and the estimated value is used as a control index for ozone injection.

A twenty-seventh aspect of the present invention is characterized in that an upper limit setting of the ozone concentration in the aqueous solution of ozone treatment is added in the feedback correction.

The twenty-eighth invention is characterized in that ozone is injected by feedforward control and feedback control using the ozone injection rate.

A twenty-ninth aspect of the present invention relates to a method for controlling the ozone injection rate so that the trihalomethane generation ability (THMFP) of the activated carbon treated water becomes constant when the water to be treated is subjected to ozone injection in an ozone contact pond. After measuring the UV absorbance and the water temperature of the treated water, the UV absorbance A (abs / 50 mm) of the treated water, the water temperature T (° C.) and the dissolved ozone concentration constant control set value C (mg / L) are calculated by the following formulas. ), The ozone injection rate D (mg / L) determined by substituting C = 0 is determined by feedback correction using the THMFP estimated value of the activated carbon treated water and the THMFP constant control set value. .

D = a · A + b · T + c · C + d where a, b, c, and d are constants.
It is characterized by being obtained using the following activated carbon treated water THMFP estimation formula TH1.

TH1 = a.A2 + b.T2 + c where A2 is the ultraviolet absorbance of the activated carbon treated water, T2 is the temperature of the activated carbon treated water, a, b, and c are constants. The present invention is characterized in that the activated carbon treated water THMFP is estimated in real time using the measurable ultraviolet absorbance and the water temperature of the activated carbon treated water.

A thirty-second invention is directed to the activated carbon treated water THMF.
P is grasped in real time as an estimated value, and this estimated value is used as a control index for ozone injection.

A thirty-third aspect of the present invention is characterized in that an ozone treatment aqueous ozone concentration upper limit setting is added in the feedback correction.

A thirty-fourth invention is characterized in that ozone is injected by feedforward control and feedback control using the ozone injection rate.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 is an explanatory diagram showing the construction of an ozone / activated carbon treatment demonstration plant using a lake as a water source and a process ∪V meter (ultraviolet absorbance meter) installed. Measure. After the measurement, in order to grasp the water quality of the ozone / activated carbon treatment process water in real time using ΔV, and to optimize the treatment by using the control, the consumption of potassium permanganate and trihalomethane The results of a study on the estimation of the insoluble organic index such as the production ability using UV and the ozone injection control formula using the UV based on the UV measurement data at the demonstration plant are shown below.

First, referring to FIG. 1, reference numeral 1 denotes a raw water tank into which raw water from lake water or the like is introduced. Raw water in the raw water tank 1 is guided to a coagulation sedimentation tank 2. At this time, the raw water is guided to the coagulation sedimentation basin 2 through the coagulant (PAC). The treated water of the coagulation sedimentation basin 2 is supplied to the front sand filtration basin 3 and filtered. The filtered water is introduced into an ozone contact pond 4 to which ozone is supplied from an ozone generator (not shown). This ozone contact pond 4
Is composed of a first ozone contact tank 4a, a second ozone contact tank 4b, a first retention tank 4c, and a second retention tank 4d. The treated water subjected to ozone treatment in the ozone contact pond 4 is guided to the activated carbon contact pond 5, passes through the mixing pond 6, and then passes through the back sand filter pond 7.
After being supplied to the city, it becomes tap water. The mixing pond 6 is supplied with NaClO.

In FIG. 1, a process UV meter (low concentration UV meter (50 mm cell)) U
A process UV meter (low-concentration UV meter (100 mm cell)) UV2 is provided at the outlet of the activated carbon contact pond 5. UVO ₃ is a process for UV meter (ozone treatment of water for UV meter (100 mm cell)), the UVO ₃ during drawing-
Is selected and measured. The part is the outlet of the second ozone contact tank 4b, the part is the outlet of the first retention tank 4c, and the part is near the outlet of the second retention tank 4d.

The results of a study based on the UV measurement data in the demonstration plant configured as described above will be described below.

Result 1: Estimation of organic matter index using UV The consumption amount of potassium permanganate (hereinafter referred to as K) in each process water of ozone-treated raw water (sand filtration water), ozone-treated water and activated carbon-treated water
Estimation formulas for MnO ₄ consumption) and trihalomethane generating ability (hereinafter referred to as THMFP) were obtained. The estimation formula is shown below. UV is the absorbance at a wavelength of 253.7 nm and was measured with a process UV meter.

[0047] <KMn0 ₄ consumption estimation _{formula> C 1 = a 1 · A} 1 + b 1 (1) C 2 = a 2 · A 2 + b 2 · {1- (A 2 / A 1)} + c 2 ( _{2) C 3 = a 3 ·} a 3 + b 3 (3) wherein, C _1: KMn0 ₄ consumption of ozone treatment raw water (mg / L) a _1: ozone treatment raw water _{UV (abs / 50mm) C 2} : KMn0 ₄ consumption of ozone treated water (mg / L) a _2: ozone treated water _{UV (abs / 50mm) C 3} : KMn0 4 consumption of the activated carbon-treated water (mg / L) a _3: activated carbon treated water UV (Abs / 50 mm) a ₁ , a ₂ , a ₃ , b ₁ , b ₂ , b ₃ , c ₂ : constant <Estimation formula of THMFP> C ₄ = a ₄ · A ₄ + b ₄ · T ₄ + c ₄ · B ₄ + d ₄ (4) C ₅ = a ₅ · A ₅ + b ₅ · T ₅ + c ₅ (5) where C ₄ : THMFP (μg / L) of ozonized raw water A ₄ : UV (abs) of ozonized raw water / 50mm) T _4: ozone treatment Raw water temperature (℃) B _4: bromide ion (Br ^-) Concentration (mg / L) C _5: ozonated water, the activated carbon treated water THMFP ([mu] g
/ L) A _5: ozone treated water, the activated carbon-treated water UV (abs / 50m
m) T ₅ : Water temperature (° C.) of ozone-treated water and activated carbon-treated water a ₄ , b ₄ , c ₄ , d ₄ , a ₅ , b ₅ , c ₅ : constants The above estimation formulas are all correlation coefficients ( Or multiple correlation coefficients), and using the above-described equations (1) to (5) using explanatory variables such as UV, water temperature, and bromide ion concentration, the potassium permanganate consumption of the ozone / activated carbon treatment process water, It was found that the index of hardly decomposable organic matter such as trihalomethane formation ability can be estimated with high accuracy.

Result 2: In an ozone contact pond composed of an ozone injection control type contact tank using UV and a retention tank,
The ozone injection rate D operated at the constant dissolved ozone concentration control at the outlet of the contact tank could be expressed by a multiple regression equation (multiple correlation coefficient = 0.99) using the ozone-treated raw water UV, the water temperature, and the dissolved ozone concentration.

D = a _5.5 · A _5.5 + b _5.5 · T _5.5 + c _5.5 · C _5.5 + d _5.5 (5.5) D: Ozone injection rate (mg / L) A _5.5 : UV of the ozonized raw water (abs / 50 mm) T _5.5 : Water temperature of ozonized raw water (° C) C _5.5 : Dissolved ozone concentration at the outlet of the contact tank (mg / L) a _5.5 , b _5.5 , c _5.5 , d _5.5 : constant The above equation (5.5) is the dissolved ozone concentration By replacing C _5.5 , which is a term, with the dissolved ozone concentration constant control set value,
Ozone injection rate can be used as feed forward control. The control formula is shown below.

D = a ₆ · A ₆ + b ₆ · T ₆ + c ₆ · C ₆ + d ₆ (6) D: Ozone injection rate (mg / L) A ₆ : UV (abs / 50 mm) of ozonized raw water T ₆ : Water temperature of ozonized raw water (° C) C ₆ : Dissolved ozone concentration constant control set value (mg / L) a ₆ , b ₆ , c ₆ , d ₆ : constant By substituting the measured value of the water temperature and the set value of the dissolved ozone concentration constant control, the ozone injection rate for feedforward control can be determined.

The present invention based on the above results uses the ultraviolet absorbance, which is widely used as an index of the hardly decomposable organic matter, to identify the hardly decomposable organic matter which is one of the substances to be removed from the ozone / activated carbon treated water. This is a method of controlling the ozone injection rate.

Conventionally, it is about the constant control of the treated water of the ozonized water and the activated carbon treated water, and is based only on the feedback control. The present invention is different from the prior art in that the present invention is based on a combination of feedforward control and feedback control based on the above-described implementation results.

Hereinafter, embodiments of the present invention will be described.

<First Embodiment: Feed Forward Control of Ozone Injection Rate Using UV> The control of this first embodiment is based on the UV, water temperature, dissolved ozone concentration set value of the ozonized raw water, and the above equation (6). This is a method for determining the ozone injection rate (feed forward (FF) control).

FIG. 2 is an explanatory view of the structure of the first embodiment.
In the embodiment, the ozone contact pond 4 including the first and second ozone contact tanks 4a and 4b and the first and second retention tanks 4c and 4d is controlled as follows. In FIG. 2, CT
RL1~3 is controller, O ₃ G ozone generator, O ₃ CT is injected ozone densitometer, FT2 is injected ozone gas flow meter, U
VT is a UV meter, WT is a thermometer, and FT1 is an ozonated raw water flow meter.

In the first embodiment configured as described above, the ozone-treated raw water U is measured by the ΔV meter UVT and the thermometer WT.
V and the water temperature are each continuously measured. By performing the continuous measurement in this manner, the control of the first embodiment can be applied in a case where the ozone injection rate can be estimated with high accuracy as shown in Expression (6).

The control of the first embodiment is performed as follows. First, the ozone-treated raw water UV, the raw water quality measurement signal of the water temperature, and the dissolved ozone concentration constant control set value DO ₃ SP are given as input signals to the controller CTRL1, and the ozone injection rate set value DSP is determined by equation (6). . After that, in the controller CTRL2, the flow rate of the ozonized raw water from the FT1,
The injection ozone concentration set value O ₃ CSP is determined from the flow rate of the injected ozone gas from the FT 2 and the DSP determined by the CTRL 1. Then, the injected ozone concentration of the ozone contact pond 4 becomes
Injection ozone concentration set value O ₃ CS determined by CTRL2
It is controlled to be P. By applying the ozone injection rate FF control using the water quality of the ozonized raw water flowing into the ozone contact pond 4, rapid ozone injection can be performed even when the raw water quality changes.

As described above, in the first embodiment, the necessary ozone is obtained by using the water quality items such as the UV and the water temperature of the inflowing ozone-treated raw water, the dissolved ozone concentration set value, and the ozone injection rate determination formula using these as explanatory variables. The injection rate becomes identifiable. In addition, there is an advantage that the ozone can be quickly injected even when the raw water quality changes.

<Second Embodiment: Dissolved Ozone Concentration Constant Control> In the second embodiment, the ozone injection rate is determined using the UV, water temperature, dissolved ozone concentration constant control set value of the ozonized raw water, and the above equation (6). Method (feed forward (FF) control)
The control is a combination of a method (feedback (FB) control) for correcting the ozone injection rate by comparing the ozone treatment aqueous ozone concentration with the dissolved ozone concentration constant control set value.

FIG. 3 is an explanatory view of the configuration of the second embodiment. The same parts as those of the first embodiment are denoted by the same reference numerals and described. In FIG. 3, the second mode is an ozone contact pond 4, a controller CTRL 1,
2,3, ozone generator O ₃ G, injecting ozone densitometer O ₃ C
T, injection ozone gas flow meter FT2, UV meter UVT, thermometer WT, ozone-treated raw water flow meter FT1, and dissolved ozone concentration meter DO ₃ T. UV meter UVT, thermometer WT
Then, UV and water temperature of the ozonized raw water are continuously measured. The dissolved ozone concentration is continuously measured with a dissolved ozone concentration meter DO ₃ T.

The FF controller of the controller CTRL1 receives as input signals the ozone-treated raw water UV, the water temperature measurement signal of the water temperature, and the dissolved ozone concentration constant control set value DO ₃ SP,
The ozone injection rate for FF control (hereinafter, referred to as D1) is determined by equation (6). On the other hand, in the FB control unit of the controller CTRL1, a dissolved ozone concentration constant control set value DO ₃ SP and a measurement signal of the ozone concentration of the dissolved ozone solution are given as input signals. , D2) are determined.

The output D1 of the FF control unit and the output D2 of the FB control unit are added to determine the ozone injection rate set value DSP by the combination control. In the controller CTRL2, the injected ozone concentration O ₃ CSP is determined from the ozone-treated raw water flow rate, the injected ozone gas flow rate, and the DSP determined by CTRL1. Then, the concentration of ozone injected into the ozone contact pond 4 is CT
It is controlled so as to become O ₃ CSP determined by RL2.

By combining the FB control with the ozone injection rate FF control using the quality of the inflowing ozone-treated raw water, rapid ozone injection can be performed even when the quality of the raw water is fluctuated. Can be expected to improve stability.

In the second embodiment, the following effects can be obtained. (A) Using the water quality items such as UV and water temperature of the incoming ozonized raw water, the dissolved ozone concentration set value, and the ozone injection rate determination formula (formula (6)) using these as explanatory variables,
The ozone injection rate necessary for the quality of the ozonized raw water can be found. (B) Based on the ozone injection rate using the equation (6), quick ozone injection can be performed even when the raw water quality changes. (C) By correcting the ozone injection rate using the equation (6) using a feedback control term based on the measured value of the present dissolved ozone concentration, the ozone injection rate that realizes stable ozone treatment can be determined. (D) Ozone injection feed-forward combined feed-forward control combining the dissolved ozone concentration constant feedback control with the ozone injection rate feed-forward control using the quality of the inflowing ozone-treated raw water enables rapid response to fluctuations in raw water quality. Ozone injection can be performed, and improvement in processing stability can be expected as compared with the case where feedback control is performed alone.

<Third Embodiment: Ozonized Water UV Constant Control (with Dissolved Ozone Concentration Upper Limit Setting)> In the third embodiment, the UV, water temperature, dissolved ozone concentration constant control set value of the ozonized raw water and the above equation (6) are calculated. To determine the ozone injection rate (feed forward (FF) control)
This is a combination control of a method (feedback (FB) control) of correcting the ozone injection rate by comparing the V constant control set value with the ozone-treated water UV.

FIG. 4 is a structural explanatory view showing a third embodiment.
The same parts as those in the embodiment will be described with the same reference numerals. In FIG. 4, a third mode is an ozone contact pond 4, a controller CTRL.
1, 2, 3, ozone generator O ₃ G, injected ozone concentration meter O ₃
CT, injection ozone gas flow meter FT2, ozone-treated raw water UV meter UVT, thermometer WT, ozone-treated raw water flow meter FT
1. It consists of a dissolved ozone concentration meter DO ₃ T and a UV meter UVO ₃ T for ozonated water.

Ozone-treated raw water UV meter UVT, thermometer W
At T, the UV and the water temperature of the ozonized raw water are continuously measured. UV meter for ozonated water UVT, dissolved ozone concentration meter D
O ₃ T is used to continuously measure the UV and the dissolved ozone concentration of the ozonated water.

In the FF control section, water quality measurement signals of the ozone-treated raw water UV and the water temperature are given as input signals, and the ozone injection rate D ₁ for FF control is determined by equation (6). The dissolved ozone concentration constant control set value of the equation (6) is set to “0” (mg / L). This setting corresponds to the ozone treatment raw water quality that varies, further ozone injection rate D ₁ of the degree to which the dissolved ozone concentration is not detected by UV ozone treated water is determined.

In the FB control unit, two measurement signals of the UV of the ozonized water and the concentration of the dissolved ozone in the ozone-treated water, the set value of the UV-constant water UV value constant control (UVSP) and the set value of the dissolved ozone concentration upper limit (DO ₃ ULSP) ) Are given as input signals, and the ozone injection rate D is calculated by the following equation.
Calculate and determine ₂ .

D ₂ = k ₇ · (UV _{sp −UV} ) (when DO ₃ <DO _{3 ulsp} ) (7) D ₂ = k ₈ · (DO _3ulsp −DO ₃ ) (when DO ₃ ≧ DO _3ulsp ) 8) Here, UV _sp : Ozone treated water UV constant control set value (abs / 50m
m) UV: ozone treated water _{UV (abs / 50mm) DO 3ulsp} : Dissolved ozone concentration upper limit set value of the ozone treated water (mg / L) DO _3: Dissolved ozone concentration of the ozone treated water _{(mg / L) k 7,} k ₈ : Constant The FB controller combined UV constant control with dissolved ozone concentration upper limit control. The dissolved ozone concentration upper limit control is for avoiding an ozone injection and an increase in dissolved ozone concentration that may occur when the treated water UV is not reduced to the UV constant control set value. If the dissolved ozone is too high, the injected ozone is not only wasted, but also may adversely affect the subsequent activated carbon treatment (biological activated carbon). The dissolved ozone concentration upper limit set value is set in consideration of this. When the dissolved ozone concentration does not exceed the upper limit setting performs determination of D ₂ on the basis of the treated water UV using Equation (7),
If the dissolved ozone concentration exceeds the upper limit set to avoid any more ozone injected using the equation (8), the determination of D ₂ based on the dissolved ozone concentration.

[0071] and the output D ₁ of the FF controller, in addition to the output D ₂ of the FB control unit, an ozone injection rate combination control DSP
Is determined. In the controller CTRL2, the injected ozone concentration O ₃ CSP is obtained from the ozone treated raw water flow rate, the injected ozone gas flow rate, and the ozone injection rate DSP determined by the controller CTRL1.
Is determined. Then, the injected ozone concentration of the ozone contact pond 4 is determined by the injected ozone concentration O determined by the controller CTRL2.
₃ Controlled to be CSP. Since this control method is a method of directly grasping the water quality of the ozonized water by the UV value and injecting ozone in accordance with the UV value, the ozone treatment is more intense than the control method of indirectly grasping the water quality, such as dissolved ozone concentration control. The injection rate can be reduced.

Further, it is expected that the FF control unit can stabilize the processing for the fluctuation of the raw water quality. The realization of the constant control of the quality of the treated water can provide a stable treated water with respect to fluctuations in the quality of the raw water, and at the same time, can prevent excessive injection of ozone and enable efficient ozone treatment.

The effects of the third embodiment will be described below.

(A) The ozone-treated raw water UV, water temperature, and water quality items such as UV and water temperature of the inflowing ozone-treated raw water, and the ozone injection rate determination formula (Equation (6)) using the dissolved ozone concentration constant control set value as an explanatory variable. By substituting “0” mg / L as the current measured value of “1” and the dissolved ozone concentration constant control setting value, the ozone injection rate according to the quality of the ozonized raw water can be determined.

(B) Based on the ozone injection rate using equation (6), it becomes possible to inject ozone quickly even with fluctuations in the quality of raw water.

(C) By directly using ozone-treated water UV, which is the quality of ozone-treated water, as the control amount in the feedback control term, ozone injection based on water quality can be achieved more than in a control method using an ozone concentration index as a control amount. Becomes possible.

(D) The ozone injection rate using the equation (6) is
By performing correction using a feedback control term based on the UV measurement value of the ozonated water, the ozone injection rate that realizes stable ozonation can be determined.

(E) By combining the constant control of the ozone-treated water UV with the upper limit setting of the dissolved ozone concentration, it is possible to prevent excessive ozone injection and an increase in the dissolved ozone concentration, which are considered to occur when the ozone-treated water UV is not reduced to the target value. I can do it.

(F) An ozone injection feedforward / feedback feedback control combining an ozone injection rate feedforward control using the quality of the inflowing ozonized raw water and a feedback control of the ozone treated water UV constant (with an upper limit of dissolved ozone concentration). In addition, rapid ozone injection can be performed even when the raw water quality fluctuates, and the stability of the treatment can be expected to be improved as compared with the case where the feedback control is performed alone.

<Fourth Embodiment: Constant Control of Consumption of Ozonated Water KMnO ₄ (with Upper Limit Setting of Dissolved Ozone Concentration)> In a fourth embodiment, the set value of the constant control of UV, water temperature and dissolved ozone concentration of the ozonized raw water and the above equation ( 6), the ozone injection rate is determined (feed forward (FF) control), and the ozone-treated water KMnO ₄ consumption constant control set value is compared with the ozone-treated water KMnO ₄ consumption estimated value. This is a combination control of a method (feedback (FB) control) for correcting the injection rate. In particular, in the fourth embodiment, the equation (2) is used to calculate the estimated value of the consumption of ozonized water KMnO ₄ ,
The present invention can be applied to a case where the KMnO ₄ consumption amount of the ozonized water can be estimated with high accuracy by the water quality index that can be continuously measured as in the equation (2).

FIG. 5 is an explanatory view showing the structure of the fourth embodiment.
The same parts as those in the embodiment will be described with the same reference numerals. In FIG. 5, the fourth mode is an ozone contact pond 4, a controller CTRL.
1, 2, 3, ozone generator O ₃ G, injected ozone concentration meter O ₃
CT, injection ozone gas flow meter FT2, ozone-treated raw water UV meter UVT, thermometer WT, ozone-treated raw water flow meter FT
1. It consists of a dissolved ozone concentration meter DO ₃ T and a UV meter UVO ₃ T for ozonated water.

Ozone-treated raw water UV meter UVT, thermometer W
At T, the UV and the water temperature of the ozonized raw water are continuously measured. UV meter for ozonated water UVT, dissolved ozone concentration meter D
O ₃ T is used to continuously measure the UV and the dissolved ozone concentration of the ozonated water.

The FF control section supplies the water quality measurement signals of the ozone-treated raw water UV and the water temperature as input signals, and determines the FF control ozone injection rate D _{1 according} to equation (6). The dissolved ozone concentration constant control set value of the equation (6) is set to “0” (mg / L). This setting corresponds to the ozone treatment raw water quality that varies, further ozone injection rate D ₁ of the degree to which the dissolved ozone concentration is not detected by the ozonated water is determined.

In the FB control unit, the KMnO of the ozonized water is
₍₄ ) Estimate the consumption value by using ozone-treated raw water UV and
V, the estimated value, the ozone-treated water-soluble ozone concentration, the ozone-treated water KMnO ₄ consumption constant control set value C ₃ SP, and the dissolved ozone concentration upper-limit set value DO ₃
The ULSP value is given as an input signal, and D ₂
Is calculated and determined.

D ₂ = k ₉ · (C _3sp -C ₃ ) (when DO ₃ <DO _3ulsp ) (9) D ₂ = k ₁₀ · (DO _3ulsp -DO ₃ ) (when DO ₃ ≧ DO _3ulsp ) (10) Here, C _3sp : Ozone-treated water KMnO ₄ consumption constant control set value (mg / L) C ₃ : Ozone-treated water KMnO ₄ consumption estimated value (mg / L) DO _3ulset : _{Dissolution of} ozone-treated water Ozone concentration upper limit setting value (mg / L) DO ₃ : Dissolved ozone concentration of ozonized water (mg / L) k ₉ , k ₁₀ : Constant The estimated value of KMnO ₄ consumption of ozonated water is the same as that of ozone-treated raw water. It is calculated from equation (2) using two water quality signals of UV of the ozonized water. The estimated value calculation takes into account the time delay of the ozonized water obtained from the ozone-treated raw water and the result of the ozone treatment. This time delay changes depending on the flow rate of the ozonized raw water.

The FB control unit is a combination of constant control of the consumption of ozone-treated water KMnO _{4 and} upper limit control of the dissolved ozone concentration. The dissolved ozone concentration upper limit control is for avoiding ozone injection and an increase in dissolved ozone concentration, which can occur when the consumption (estimated value) of the ozone-treated water KMnO ₄ is not reduced to the KMnO ₄ consumption constant control set value. .

If the dissolved ozone is too high, not only is the injected ozone wasted, but it may adversely affect the subsequent activated carbon treatment (biological activated carbon). The dissolved ozone concentration upper limit set value is set in consideration of this. If the dissolved ozone concentration does not exceed the upper limit setting, D ₂ is determined based on the estimated value of the consumption of ozonized water KMnO ₄ using equation (9), and if the dissolved ozone concentration exceeds the upper limit setting, ,
To avoid further ozone injected using the equation (10), the determination of D ₂ based on the dissolved ozone concentration.

[0088] In addition the output D ₂ outputs D ₁ and FB control unit of the FF controller, the ozone injection rate of the combination control DSP is determined. In the controller CTRL2, the ozone-treated raw water flow rate, the injected ozone gas flow rate, and the DS determined by CTRL1 are used.
The injection ozone concentration O ₃ CSP is determined from P. Then, the injection ozone concentration of the ozone contact pond 4 is controlled so as to be O ₃ CSP determined by CTRL2.

K, one of the substances to be removed in the ozone treatment
MnO_FourThere is no means to measure consumption in real time.
(Analytical methods are available, but they are not simple and require time and effort.
The measured value cannot be applied to ozone injection control. Oh
UV that can be measured in situ gives real-time results
Therefore, by using the equation (2), a highly accurate KMnO _Four
Consumption estimates can be obtained in real time.

In the control method of the fourth embodiment, KMnO ₄ consumption is directly grasped as UV and an estimated value calculated by the equation (2).
Since the ozone is injected according to the method, it is expected that the ozone injection rate can be further reduced as compared with the control method in which the water quality is indirectly grasped, such as the dissolved ozone concentration control. In addition, the FF control unit can be expected to stabilize the processing for the fluctuation of the raw water quality. Realization of constant control of this treated water quality
At the same time, stable treated water quality can be obtained with respect to fluctuations in the raw water quality, and at the same time, excessive ozone injection can be prevented, and efficient ozone treatment can be performed.

In the fourth embodiment, the following effects can be obtained.

(A) The ozone-treated raw water UV and the water temperature are calculated using the water quality items such as the UV and the water temperature of the inflowing ozone-treated raw water and the ozone injection rate determining formula (Equation (6)) using the dissolved ozone concentration constant control set value as an explanatory variable. By substituting “0” mg / L as the current measured value of “1” and the dissolved ozone concentration constant control setting value, the ozone injection rate according to the quality of the ozonized raw water can be determined.

(B) Based on the ozone injection rate using the equation (6), rapid ozone injection can be performed even if the raw water quality changes.

(C) The UV of the ozone-treated water and the UV of the ozone-treated water are substituted into the ozone-treated water KMnO ₄ consumption estimation formula (formula (2)) using the UV of the ozonated water and the UV of the ozonated water as explanatory variables. By doing, ozonized water KMn
O ₄ consumption can be estimated with high accuracy.

(D) Since the explanatory variable in the equation (2) is a water quality item that can be measured in real time, the ozone-treated water KMn
The estimation of O ₄ consumption is made possible in real time.

(E) By directly using the estimated value of the consumption of ozonized water KMnO _4, which is the quality of ozonated water, as the control amount of the feedback control term, the water quality can be improved more than the control method using the ozone concentration index as the control amount. , It becomes possible to inject ozone.

(F) The ozone injection rate using the equation (6) is
The ozone injection rate that realizes stable ozone treatment can be determined by correcting using the ozone-treated water KMnO ₄ consumption (estimated value) feedback control term.

[0098] The (g) ozonated water KMnO ₄ consumption constant control combining the dissolved ozone concentration capping believed ozonated water KMnO ₄ consumption (estimated value) is generated if not reduced to the target value Ozone Excessive injection and increase in dissolved ozone concentration can be prevented.

(H) Ozone injection feedforward feedback combining feedforward control of the ozone injection rate using the quality of the inflowing ozone-treated raw water and feedback control of constant ozone-treated water KMnO ₄ consumption (with upper limit setting of dissolved ozone concentration) By the combination control, rapid ozone injection can be performed even when the raw water quality changes, and the stability of the treatment can be expected to be improved as compared with the case where the feedback control is performed alone.

<Fifth embodiment: Constant control of ozone-treated water THMFP (with upper limit setting of dissolved ozone concentration)> In the fifth embodiment, the UV, water temperature, dissolved ozone concentration constant control set value of the ozone-treated raw water and the above equation (6) are used. Method for determining the ozone injection rate (feed forward (FF) control) using the ozonated water THMFP constant control set value and the ozonized water THMF
This is a combination control of a method of correcting the ozone injection rate by comparing the P estimation value (feedback (FB) control).

In calculating the estimated value of the ozone-treated water THMFP,
Equation (5) is used. The control of the fifth mode is expressed by the following equation (5).
It can be applied when the THMFP of the ozonated water can be estimated with high accuracy by the water quality index that can be continuously measured as described above.

FIG. 6 is a structural explanatory view showing the fifth embodiment.
In the following description, the same parts as those of the first embodiment are denoted by the same reference numerals. The fifth embodiment is an ozone contact pond 4, a controller CTRL.
1, 2, 3, ozone generator O ₃ G, injected ozone concentration meter O ₃
CT configured, injecting ozone gas flowmeter FT2, UV meter UVT for ozone treatment raw water, thermometer WT1,2, ozone treatment raw water flow meter FT1, dissolved ozone concentration meter DO ₃ T, the UV meter UVO ₃ T for ozonated water . U for ozonated raw water
The UV meter and the water temperature of the ozonized raw water are continuously measured by a V meter UVT and a thermometer WT1. UV meter UV for ozonated water
The UV, dissolved ozone concentration, and water temperature of the ozonized water are continuously measured by T, dissolved ozone concentration meter DO ₃ T, and thermometer WT2.

The FF control section gives the water quality measurement signals of the ozone treated raw water UV and water temperature as input signals, and determines the ozone injection rate D ₁ for FF control by equation (6). Equation (6)
Is set to “0” (mg / L). This setting corresponds to the ozone treatment raw water quality that varies, further ozone injection rate D ₁ of the degree to which the dissolved ozone concentration is not detected by the ozonated water is determined.

In the FB control section, the THMF of the ozone-treated water
The estimated value of P is calculated from the ozone-treated water UV and the water temperature by the equation (5), and the estimated value and the signal of the ozone-treated water-soluble ozone concentration,
Then, the ozone-treated water THMFP constant control set value (C ₄ S
P) and the dissolved ozone concentration upper limit set value (DO ₃ ULSP) are given as input signals, and D is given by the following equation.
Calculate and determine ₂ .

D ₂ = k ₁₁ · (C _4sp -C ₄ ) (when DO ₃ <DO _3ulsp ) (11) D ₂ = k ₁₂ · (DO _3ulsp -DO ₃ ) (when DO ₃ ≧ DO _3ulsp ) (12) Here, C _4sp : ozone treated water THMFP constant control set value (μg /
L) C ₄ : Estimated value of THMFP of ozonized water (μg / L) DO _3ulset : Upper limit value of dissolved ozone concentration of ozonized water (mg / L) DO ₃ : Dissolved ozone concentration of ozonized water (mg / L) k ₁₁ , k ₁₂ : constant The THMFP estimated value of the ozonized water is the U
It is calculated from equation (5) using two water quality signals of V and water temperature.

The FB control unit was a combination of the constant control of the ozone-treated water THMFP and the control of the dissolved ozone concentration upper limit. The dissolved ozone concentration upper limit control is performed using the ozone treated water THM.
This is for avoiding the ozone injection and the increase in the dissolved ozone concentration which can occur when the FP (estimated value) is not reduced to the THMFP constant control set value. If the dissolved ozone is too high, not only is the injected ozone wasted, but it may adversely affect the subsequent activated carbon treatment (biological activated carbon).

The dissolved ozone concentration upper limit set value is set in consideration of this. When the dissolved ozone concentration does not exceed the upper limit setting performs determination of D ₂ ozonated water THMFP (estimated value) on the basis of using the equation (11), when the dissolved ozone concentration exceeds the upper limit setting, using equation (12), in order to avoid any more ozone injection, the determination of D ₂ based on the dissolved ozone concentration.

[0108] In addition the output D ₂ outputs D ₁ and F8 controller of FF controller, ozone injection rate combination control DSP
Is determined by the controller CTRL1. Controller CTRL2
Then, ozone treated raw water flow rate, injected ozone gas flow rate, CT
Injection ozone concentration O ₃ CS from DSP determined by RL1
P is determined. Then, the injected ozone concentration of the ozone contact pond 4 is the injected ozone concentration O ₃ C determined by CTRL2.
It is controlled to become SP.

T, one of the substances to be removed by the ozone treatment,
HMFP has no means to measure in real time (there is an analysis method, but it is not simple, it takes time and effort),
The measured value cannot be applied to ozone injection control. Since the results of UV and water temperature that can be measured on-site can be obtained in real time, highly accurate THMF can be obtained by using equation (5).
P estimates can be obtained in real time. The control method of the fifth embodiment is a method of directly grasping the THMFP as the UV, the water temperature, and the estimated value calculated by the equation (5) and injecting ozone in accordance therewith. Therefore, the control method is indirectly performed like the dissolved ozone concentration control. It can be expected that the ozone injection rate can be further reduced than the control method that grasps the water quality. Also, by the FF control unit,
It is also expected that the treatment of raw water quality fluctuations will be stabilized. According to the fifth embodiment, the constant control of the quality of the treated water is achieved, whereby the treated water having a stable quality with respect to the fluctuation of the quality of the raw water can be obtained, and at the same time, the excessive ozone injection can be prevented and the ozone treatment can be performed efficiently.

According to the fifth embodiment configured as described above,
The following effects can be obtained.

(A) The ozone-treated raw water UV, water temperature, and water quality items such as UV and water temperature of the inflowing ozone-treated raw water, and the ozone injection rate determination formula (equation (6)) using the dissolved ozone concentration constant control set value as an explanatory variable. By substituting “0” mg / L as the current measured value of “1” and the dissolved ozone concentration constant control setting value, the ozone injection rate according to the quality of the ozonized raw water can be determined.

(B) Based on the ozone injection rate using the equation (6), rapid ozone injection can be performed even when the raw water quality changes.

(C) Ozone-treated water THMFP estimation formula (equation (5)) using UV and water temperature as explanatory variables
By substituting the ozone-treated water UV and the water temperature into the above, the ozone-treated water THMFP can be estimated with high accuracy.

(D) Since the explanatory variable in equation (5) is a water quality item that can be measured in real time, the ozone-treated water THMF
The estimation of P becomes possible in real time.

(E) By directly using the estimated value of the ozone-treated water THMFP, which is the quality of the ozone-treated water, as the control amount of the feedback control term, the control value is more based on the water quality than the control method using the ozone concentration index as the control amount. Ozone injection becomes possible.

(F) The ozone injection rate using the equation (6) is
By correcting using the ozonated water THMFP (estimated value) feedback control term, the ozone injection rate that realizes stable ozonation can be determined.

(G) By combining the constant control of the ozone-treated water THMFP with the upper limit setting of the dissolved ozone concentration, the excess ozone injection and the dissolved ozone concentration which are considered to be generated when the ozone-treated water THMFP (estimated value) is not reduced to the target value. The rise can be prevented.

(H) An ozone injection feedforward / feedback / feedback / feedback combination control combining an ozone injection rate feedforward control using the quality of the inflowing ozonized raw water and a constant ozone-processed water THMFP (with an upper limit of dissolved ozone concentration) feedback control. In addition, quick ozone injection is possible even for fluctuations in raw water quality,
In addition, the stability of the process can be expected to be improved as compared with the case where the feedback control is performed alone.

<Sixth embodiment: UV constant control of activated carbon treated water (with upper limit setting of dissolved ozone concentration)> In the sixth embodiment, the UV, water temperature, dissolved ozone concentration constant control set value of ozonized raw water and the above equation (6) are calculated. Method for determining ozone injection rate (feed forward (FF) control) and method for correcting ozone injection rate by comparing activated carbon treated water UV constant control set value with activated carbon treated water UV (feedback (FB) Control).

FIG. 7 is a structural explanatory view showing a sixth embodiment.
In the following description, the same parts as those of the first embodiment are denoted by the same reference numerals. The sixth embodiment includes an ozone contact pond 4, an activated carbon contact pond 5,
Regulator CTRL1,2,3, ozone generator O ₃ G, injecting ozone densitometer O ₃ CT, injected ozone gas flowmeter FT2,
It is composed of a UV meter UVT for ozonated raw water, a thermometer WT, an ozonated raw water flow meter FT1, a dissolved ozone concentration meter DO ₃ T, and a UV meter UVACT for activated carbon treated water. UV meter for ozonated raw water UVT, thermometer WT for UV and water temperature of ozonated raw water, dissolved ozone concentration meter DO ₃ T for dissolved ozone concentration of ozonated water, and UV meter for activated carbon treated water U
The UV of the activated carbon treated water is continuously measured by VACT.

The FF control section supplies the water quality measurement signals of the ozone-treated raw water UV and the water temperature as input signals, and determines the ozone injection rate D ₁ for FF control by equation (6). The dissolved ozone concentration constant control set value of the equation (6) is set to “0” (mg / L). This setting corresponds to the ozone treatment raw water quality varying, D ₁ to the extent that the dissolved ozone concentration is not detected is determined further in ozone treated water.

In the FB control unit, two measurement signals of the UV of the activated carbon treated water and the ozone concentration of the dissolved water in the ozone treatment water, the set value UVACSP of the constant value control of the activated carbon treated water UV value, and the upper limit set value of the dissolved ozone concentration DO ₃ ULSP are obtained. Two set values are given as input signals, and D ₂ is calculated and determined by the following equation.

D ₂ = k ₁₃ · (UV _{acsp −UV ac} ) (when DO ₃ <DO _3ulsp ) (13) D ₂ = k ₁₄ · (DO _3ulsp −DO ₃ ) (when DO ₃ ≧ DO _3ulsp ) (14) Here, UV _acsp : Activated carbon treated water UV constant control set value (abs / 50m
m) UV _ac : Activated carbon treated water UV (abs / 50 mm) DO _3ulsp : Dissolved ozone concentration upper limit set value of dissolved ozone water (mg / L) DO ₃ : Dissolved ozone concentration of ozone treated water (mg / L) k ₁₃ , k ₁₄ : constant The FB control unit is a combination of the UV constant control and the dissolved ozone concentration upper limit control. The dissolved ozone concentration upper limit control is for avoiding an ozone injection and an increase in dissolved ozone concentration that may occur when the activated carbon treated water UV is not reduced to the UV constant control set value. If the dissolved ozone is too high, the injected ozone is not only wasted, but also may adversely affect the subsequent activated carbon treatment (biological activated carbon).

The dissolved ozone concentration upper limit set value is set in consideration of this. If the dissolved ozone concentration does not exceed the upper limit setting, D ₂ is calculated based on the activated carbon treated water UV using the equation (13).
Make decisions, if the dissolved ozone concentration exceeds the upper limit set to avoid any more ozone injected using the equation (14), the determination of D ₂ based on the dissolved ozone concentration.

By adding the output D1 of the FF control unit and the output D2 of the FB control unit, the ozone injection rate DSP of the combination control is determined. In CTRL2, the injected ozone concentration O ₃ CSP is determined from the flow rate of the ozonized raw water, the flow rate of the injected ozone gas, and the DSP determined in CTRL1. Then, the injection ozone concentration of the ozone contact pond 4 is controlled so as to be O ₃ CSP determined by CTRL2. The control method of the sixth embodiment is a method of directly grasping the water quality of the activated carbon treated water by a ΔV value and injecting ozone according to the value. Therefore, a control method in which water quality is indirectly grasped such as dissolved ozone concentration control. It is expected that the ozone injection rate can be further reduced.

The control method of the sixth embodiment is a control method for clearly positioning ozone treatment as pretreatment of activated carbon treatment and obtaining a target water quality with activated carbon treated water that is the final treatment water of ozone / activated carbon treatment ( Ozone-treated water is regarded as intermediate treatment water for ozone and activated carbon treatment). Therefore, the characteristics of each treatment process such as the physical properties of ozone (such as the lower the water temperature, the more soluble it is in water), the adsorption characteristics of activated carbon, and the biological activity when functioning as biologically activated carbon (the higher the water temperature, the higher the biological activity) Appropriate load distribution is performed in this control.
In addition, the FF control unit can be expected to stabilize the processing for the fluctuation of the raw water quality. The sixth embodiment realizes the constant control of the treated water quality so that the treated water quality stable with respect to the fluctuation of the raw water quality can be obtained, and at the same time, the excessive ozone injection can be prevented and the efficient ozone treatment can be performed.

According to the sixth embodiment configured as described above,
The following effects can be obtained.

(A) The ozone-treated raw water UV, water temperature, and water quality items such as UV and water temperature of the inflowing ozone-treated raw water, and the ozone injection rate determination formula (equation (6)) using the dissolved ozone concentration constant control set value as an explanatory variable. By substituting “0” mg / L as the current measured value of “1” and the dissolved ozone concentration constant control setting value, the ozone injection rate according to the quality of the ozonized raw water can be determined.

(B) Based on the ozone injection rate using the equation (6), quick ozone injection can be performed even when the raw water quality changes.

(C) By directly using the activated carbon treated water UV, which is the quality of the activated carbon treated water, as the control amount of the feedback control term, the ozone injection based on the water quality can be more improved than the control method using the ozone concentration index as the control amount. Becomes possible.

(D) As the control amount of the feedback control term, the ozone injection control using the activated carbon treated water UV, which is the quality of the activated carbon treated water, makes it possible to further reduce the ozone injection rate as compared with the case where the ozone treated water UV is used. Can be expected.

(E) The ozone injection rate using the equation (6) is
By correcting using the feedback control term based on the UV measurement value of the activated carbon treated water, the ozone injection rate that realizes stable ozone treatment can be determined.

(F) By combining the constant control of the activated carbon treated water UV with the upper limit setting of the dissolved ozone concentration, it is possible to prevent the excessive ozone injection and the increase of the dissolved ozone concentration which are considered to occur when the activated carbon treated water UV is not reduced to the target value. I can do it.

(G) Ozone injection feedforward control using feedwater quality of ozone-treated raw water flowing in and feed-forward control of combined ozone injection feedforward and feedback control of constant activated carbon treated water UV (with upper limit setting of dissolved ozone concentration) feedback control In addition, rapid ozone injection can be performed even when the raw water quality fluctuates, and the stability of the treatment can be expected to be improved as compared with the case where the feedback control is performed alone.

<Seventh Embodiment: Constant Control of KMnO ₄ Consumption of Activated Carbon Treated Water (with Upper Limit Setting of Dissolved Ozone Concentration)> The seventh embodiment is based on the UV, water temperature and dissolved ozone concentration constant control set values of the ozonized raw water and the above formula ( 6), a method of determining the ozone injection rate (feed forward (FF) control), and comparing the set value of the constant control of the KMnO ₄ consumption of the activated carbon treated water with the estimated value of the KMnO ₄ consumption of the activated carbon treated water. This is a combination control of a method (feedback (FB) control) for correcting the injection rate. Equation (3) is used to calculate the estimated value of the KMnO ₄ consumption of the activated carbon treated water. The control of the seventh mode is as follows.
The present invention can be applied to a case where the KMnO ₄ consumption amount of the activated carbon treated water can be estimated with high accuracy by a water quality index that can be continuously measured as in Expression (3).

FIG. 8 is a structural explanatory view showing the seventh embodiment.
In the following description, the same parts as those in the first and sixth embodiments are denoted by the same reference numerals. The seventh embodiment includes an ozone contact pond 4, an activated carbon contact pond 5, a controller CTRL 1, 2, 3, and an ozone generator O
₃ G, injecting ozone densitometer O ₃ CT, injected ozone gas flowmeter FT2, UV meter UVT for ozone treatment raw water, a thermometer WT,
Ozonated raw water flow meter FT1, dissolved ozone concentration meter DO ₃
T, composed of UV meter UVACT for activated carbon treated water.
∪V meter UVT for ozonated raw water, UV temperature of ozonized raw water with thermometer WT, UV meter UVAC for activated carbon treated water
At T, UV of activated carbon treated water and dissolved ozone concentration meter D
The dissolved ozone concentration of the ozonized water is continuously measured with O ₃ T.

The FF control section supplies water quality measurement signals of the ozone-treated raw water UV and the water temperature as input signals, and determines the ozone injection rate D ₁ for FF control by equation (6). The dissolved ozone concentration constant control set value of the equation (6) is set to “0” (mg / L). This setting corresponds to the ozone treatment raw water quality varying, D ₁ to the extent that the dissolved ozone concentration is not detected is determined further in ozone treated water.

The FB control unit calculates an estimated value of the KMnO ₄ consumption of the activated carbon treated water from the activated carbon treated water UV and the equation (3), and calculates the estimated value, the ozone concentration of the ozone-treated water-soluble ozone, and the KMnO ₄ consumption of the activated carbon treated water. Constant value control set value C ₆ SP
And the dissolved ozone concentration upper limit set value DO ₃ ULSP are given as input signals, and D ₂ is calculated and determined by the following equation.

D ₂ = k ₁₅ · (C _6sp -C ₆ ) (when DO ₃ <DO _3ulsp ) (15) D ₂ = k ₁₆ · (DO _3ulsp -DO ₃ ) (when DO ₃ ≧ DO _3ulsp ) (16) Here, C _6sp : KMnO ₄ consumption constant control set value of activated carbon treated water (mg / L) C ₆ : KMnO ₄ consumption estimated value of activated carbon treated water (mg / L) DO _3ulset : _{Dissolution of} ozone treated water Ozone concentration upper limit set value (mg / L) DO ₃ : Dissolved ozone concentration of ozonized water (mg / L) k ₁₅ , k ₁₆ : constants Activated carbon treated water KMnO ₄ consumption estimated value is calculated using ∪V of activated carbon treatment Then, it is calculated from equation (3).

The FB control unit is a combination of the constant control of the consumption of activated carbon treated water KMnO _{4 and the} control of the dissolved ozone concentration upper limit. The dissolved ozone concentration upper limit control is for avoiding ozone injection and an increase in dissolved ozone concentration that may occur when the consumption (estimated value) of the activated carbon treated water KMnO ₄ is not reduced to the KMnO ₄ consumption constant control set value. . If the dissolved ozone is too high, the injected ozone is not only wasted, but also may adversely affect the subsequent activated carbon treatment (biological activated carbon). The dissolved ozone concentration upper limit set value is set in consideration of this. When the dissolved ozone concentration does not exceed the upper limit setting performs determination of D ₂ using Equation (15) based on activated carbon treated water KMnO ₄ consumption estimates, if the dissolved ozone concentration exceeds the upper limit setting in order to avoid any more ozone injected using the equation (16), the determination of D ₂ based on the dissolved ozone concentration. In addition the output D ₂ outputs D ₁ and F8 controller of FF controller, ozone injection rate of the combination control DSP is determined. In CTRL2, the injected ozone concentration O ₃ CSP is determined from the flow rate of the ozonized raw water, the flow rate of the injected ozone gas, and the DSP determined in CTRL1. Then, the concentration of ozone injected into the ozone contact pond 4 is CT
It is controlled so as to become O ₃ CSP determined by RL2.

The consumption of KMnO _4, which is one of the substances to be removed by the ozone / activated carbon treatment, has no means for real-time measurement (there is an analysis method, but it is not simple, it takes time and effort), and the measured value is obtained. Cannot be applied to ozone injection control. Since UV that can be measured on-site can be obtained in real time, a highly accurate estimated value of KMnO ₄ consumption can be obtained in real time by using equation (3).

[0142] The control method of the seventh embodiment is the same as that of the activated carbon treated water KM.
This is a method of directly grasping nO ₄ consumption as UV and an estimated value calculated by equation (3), and injecting ozone in accordance with that. Therefore, a control method that indirectly grasps water quality, such as dissolved ozone concentration control, is used. Can also be expected to further reduce the ozone injection rate. In the control method of the seventh embodiment, the ozone treatment is clearly positioned as the pretreatment of the activated carbon treatment, and is a control method for obtaining the target water quality with the activated carbon treated water that is the final treatment water of the ozone / activated carbon treatment (the ozone treatment). Water is regarded as intermediate treatment water for ozone and activated carbon treatment).

Therefore, the properties of ozone (such as the lower the water temperature is, the more soluble it is in water), the adsorption characteristics of activated carbon, and the biological activity when functioning as biologically activated carbon (the higher the water temperature is, the higher the biological activity) is in each processing step. Load distribution according to characteristics,
This control is performed. In addition, the FF control unit can be expected to stabilize the processing for the fluctuation of the raw water quality. Realization of the constant treatment water quality control according to the seventh embodiment not only provides stable treatment water quality against fluctuations in raw water quality, but also prevents excessive ozone injection and enables efficient ozone treatment.

According to the seventh embodiment configured as described above,
The following effects can be obtained.

(A) The ozone-treated raw water UV, water temperature, and water quality items such as UV and water temperature of the inflowing ozone-treated raw water, and the ozone injection rate determination formula (Equation (6)) using the dissolved ozone concentration constant control set value as an explanatory variable. By substituting “0” mg / L as the current measured value of “1” and the dissolved ozone concentration constant control setting value, the ozone injection rate according to the quality of the ozonized raw water can be determined.

(B) Based on the ozone injection rate using the equation (6), it becomes possible to inject ozone quickly even when the raw water quality changes.

(C) Formula for estimating KMnO ₄ consumption of activated carbon treated water using UV of the activated carbon treated water as an explanatory variable (equation (3))
By substituting the activated carbon treated water UV into the water, the consumption of the activated carbon treated water KMnO ₄ can be estimated with high accuracy.

(D) Since the explanatory variables in equation (3) are water quality items that can be measured in real time, the activated carbon treated water KMnO
₄ Estimation of consumption can be made in real time.

(F) By directly using the estimated value of the consumption of the activated carbon treated water KMnO _4, which is the quality of the activated carbon treated water, as the control amount of the feedback control term, the water quality can be improved more than the control method using the ozone concentration index as the control amount. , It becomes possible to inject ozone.

(G) The ozone injection control using the activated carbon treated water KMnO ₄ consumption (estimated value), which is the quality of the activated carbon treated water, as the control amount of the feedback control term is more effective than the case where the ozone treated water is used. The ozone injection rate can be reduced more.

(H) The ozone injection rate using the equation (6) is
By correcting using the KMnO ₄ consumption (estimated value) feedback control term of the activated carbon treated water, the ozone injection rate for realizing stable ozone treatment can be determined.

[0152] (i) ozone by combining the dissolved ozone concentration limit set to the activated carbon-treated water KMnO ₄ consumption constant control, believed to activated carbon treated water KMnO ₄ consumption (estimated value) is generated if not reduced to the target value Excessive injection and increase in dissolved ozone concentration can be prevented.

(J) Ozone injection feedforward feedback combining feedforward control of the ozone injection rate using the quality of the inflowing ozone-treated raw water and feedback control of constant consumption of activated carbon-treated water KMnO ₄ (with upper limit setting of dissolved ozone concentration) By the combination control, rapid ozone injection can be performed even when the raw water quality changes, and the stability of the treatment can be expected to be improved as compared with the case where the feedback control is used alone. <Eighth embodiment: THMFP constant control of activated carbon treated water (with upper limit setting of dissolved ozone concentration)>
The eighth embodiment is a method of determining the ozone injection rate (feed forward (FF) control) using the UV, water temperature, dissolved ozone concentration constant control set value and the above equation (6), and the activated carbon treated water THMFP. This is a combination control of a method (feedback (FB) control) of correcting the ozone injection rate by comparing the fixed control set value with the estimated value of the activated carbon THMFP. Equation (5) is used to calculate the THMFP estimated value of the activated carbon treated water. The control in the eighth mode is expressed by the following equation (5).
It can be applied when the THMFP of the activated carbon treated water can be estimated with high accuracy by the water quality index that can be continuously measured as described above. FIG. 9 is a configuration explanatory view showing an eighth embodiment. In FIG. 9, the same parts as those in the first embodiment and the seventh embodiment are denoted by the same reference numerals. Eighth embodiment, ozone contact basin 4, activated carbon contacting pond 5, control CTRL1,2,3, ozone generator O ₃
G, injected ozone concentration meter O ₃ CT, injected ozone gas flow meter FT2, ozone treated raw water ΔV meter UVT, thermometer WT
1, 2, ozone-treated raw water flow meter FT1, dissolved ozone concentration meter DO ₃ T, ΔV meter UVACT for activated carbon treated water. Ozone-treated raw water UV meter UVT, thermometer WT1
UV and water temperature of ozone-treated raw water, UV for activated carbon-treated water
The UV and water temperature of the activated carbon treated water are continuously measured by a UVACT meter and a thermometer WT2, and the dissolved ozone concentration of the ozonized water is continuously measured by a dissolved ozone concentration meter DO ₃ T.

The FF control section supplies the water quality measurement signals of the ozone-treated raw water UV and the water temperature as input signals, and determines the ozone injection rate D ₁ for FF control by equation (6). The dissolved ozone concentration constant control set value of the equation (6) is set to “0” (mg / L). This setting corresponds to the ozone treatment raw water quality varying, D ₁ to the extent that the dissolved ozone concentration is not detected is determined further in ozone treated water.

The FB control unit calculates a THMFP estimated value of the activated carbon treated water from the activated carbon treated water UV, the water temperature, and the equation (5), and calculates the estimated value and a signal of the ozone concentration in the ozone treated water-soluble ozone concentration.
And the activated carbon treated water THMFP constant control set value C ₇ SP
And the dissolved ozone concentration upper limit set value DO ₃ ULSP are given as input signals, and D ₂ is calculated and determined by the following equation.

D ₂ = k ₁₇ · (C _7sp -C ₇ ) (when DO ₃ <DO _3ulsp ) (17) D ₂ = k ₁₈ · (DO _3ulsp -DO ₃ ) (when DO ₃ ≧ DO _3ulsp ) (18) Here, C _7sp : THMFP constant control set value (μg /
L) C ₇ : THMFP estimated value of activated carbon treated water (μg / L) DO _3ulset : Upper limit value of dissolved ozone concentration of _ozonated water (mg / L) DO ₃ : Dissolved ozone concentration of ozonized water (mg / L) k ₁₇ , k ₁₈ : constant The THMFP estimated value of the activated carbon treated water is the UV of the activated carbon treated water.
Using equation (5) and the water temperature.

The FB control unit is a combination of THMFP constant control of activated carbon treated water and dissolved ozone concentration upper limit control. Dissolved ozone concentration upper limit control is activated carbon treated water THM
This is for avoiding an ozone injection and an increase in the dissolved ozone concentration that can occur when the FP (estimated value) is not reduced to the THMFP constant control set value. If the dissolved ozone is too high, the injected ozone is not only wasted, but also may adversely affect the subsequent activated carbon treatment (biological activated carbon). The dissolved ozone concentration upper limit set value is set in consideration of this. If the dissolved ozone concentration does not exceed the upper limit setting, D ₂ is determined based on the estimated value of the activated carbon treated water THMFP using Expression (17), and if the dissolved ozone concentration exceeds the upper limit setting, the expression (17) is used. 17), to avoid further injection of ozone, D
_Make decision ₂ .

The output D ₁ of the FF controller and the output D ₂ of the FB controller are added to determine the ozone injection rate DSP of the combination control. In CTRL2, the injected ozone concentration O ₃ CSP is determined from the flow rate of the ozonized raw water, the flow rate of the injected ozone gas, and the DSP determined in CTRL1. Then, the injection ozone concentration of the ozone contact pond 4 is controlled so as to be O ₃ CSP determined by CTRL2.

THMFP, which is one of the substances to be removed by the ozone / activated carbon treatment, has no means for real-time measurement (there is an analysis method, but it is not simple, it takes time and effort), and the measured value is injected with ozone. Not applicable for control.
Since UV and water temperatures that can be measured on-site can be obtained in real time, a high-precision T
An HMFP estimate can be obtained in real time.

The control method according to the eighth embodiment is based on the activated carbon treated water TH
This is a method of directly grasping the MFP as UV, water temperature, and an estimated value calculated by the equation (5), and injecting ozone in accordance therewith. Therefore, compared with a control method in which water quality is indirectly grasped, such as control of dissolved ozone concentration, In addition, the ozone injection rate can be further reduced.

In the control method of the eighth embodiment, the ozone treatment is clearly positioned as the pretreatment of the activated carbon treatment, and the target water quality is obtained with the activated carbon treated water that is the final treated water of the ozone / activated carbon treatment. (Positioned ozonated water is intermediate treated water for ozone / activated carbon treatment.)

Therefore, the properties of ozone (such as the lower the water temperature is, the more easily it dissolves in water), the adsorption characteristics of activated carbon, and the biological activity when functioning as biologically activated carbon (the higher the water temperature, the higher the biological activity), are used in each processing step. The load distribution according to the characteristic is performed by this control. Also, by the FF control unit,
It is also expected that the treatment of raw water quality fluctuations will be stabilized. Realization of the constant control of the treated water quality in the eighth embodiment makes it possible to obtain a treated water quality that is stable with respect to fluctuations in the quality of the raw water, and at the same time, it is possible to prevent excessive injection of ozone, thereby enabling efficient ozone treatment.

According to the eighth embodiment configured as described above,
The following effects can be obtained.

(A) The ozone-treated raw water UV, water temperature, and water quality items such as UV and water temperature of the inflowing ozone-treated raw water and the ozone injection rate determination formula (Equation (6)) using the dissolved ozone concentration constant control set value as an explanatory variable are shown in FIG. By substituting “0” mg / L as the current measured value of “1” and the dissolved ozone concentration constant control setting value, the ozone injection rate according to the quality of the ozonized raw water can be determined.

(B) Based on the ozone injection rate using the equation (6), it becomes possible to inject ozone quickly even when the raw water quality changes.

(C) Activated carbon treated water THMFP estimation formula (expression (5)) using UV and water temperature as explanatory variables
The activated carbon-treated water THMFP can be estimated with high accuracy by substituting the activated carbon-treated water UV and the water temperature into the water.

(D) Since the explanatory variable in equation (5) is a water quality item that can be measured in real time, the activated carbon treated water THMF
The estimation of P becomes possible in real time.

(E) By directly using the estimated value of the activated carbon treated water THMFP, which is the quality of the activated carbon treated water, as the control amount of the feedback control term, the control value is more based on the water quality than the control method using the ozone concentration index as the control amount. Ozone injection becomes possible.

(F) The control amount of the feedback control term is activated carbon treated water THMFP, which is the quality of activated carbon treated water.
The ozone injection control using the (estimated value) can further reduce the ozone injection rate as compared with the case where the ozone-treated water is used.

(G) The ozone injection rate using the equation (6) is
By performing correction using the activated carbon treated water THMFP (estimated value) feedback control term, the ozone injection rate that realizes stable ozone treatment can be determined.

(H) By combining the constant control of the activated carbon treated water THMFP with the upper limit setting of the dissolved ozone concentration, the excess ozone injection and the dissolved ozone concentration considered to occur when the activated carbon treated water THMFP (estimated value) is not reduced to the target value. The rise can be prevented.

(I) Ozone injection feed-forward control using the quality of the ozone-treated raw water flowing in and feed-forward control combined with feed-forward feedback control of constant activated carbon treated water THMFP (with upper limit setting of dissolved ozone concentration) feedback control. In addition, quick ozone injection is possible even for fluctuations in raw water quality,
In addition, the stability of the process can be improved as compared with the case where the feedback control is performed alone.

[0173]

As described above, according to the present invention,
Since the required ozone injection rate is known, it is possible to quickly inject ozone even when the raw water quality changes. In addition, by correcting the ozone injection rate using feedforward feedback control based on the dissolved ozone concentration measurement value, the ozone injection rate that realizes stable ozone treatment can be determined. Furthermore, since the feedforward control and the feedback control are combined, rapid ozone injection can be performed even when the raw water quality fluctuates, and improvement in the processing stability can be expected as compared to the case where the feedback control is performed alone. In addition, the dissolved ozone concentration can be prevented from increasing, and the ozone-treated water KMnO ₄ consumption, THMFP
Can be estimated with high accuracy, and the same effect can be obtained in the case of activated carbon treated water.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view in which a process UV meter is installed in an ozone / activated carbon treatment demonstration plant.

FIG. 2 is a configuration explanatory diagram of a first embodiment (ozone injection rate feedforward control using UV) of the first embodiment of the present invention.

FIG. 3 is a configuration explanatory view of a second embodiment (dissolved ozone concentration constant control) of the second embodiment of the present invention.

FIG. 4 shows a third embodiment (ozone-treated water UV) of the present invention.
FIG.

FIG. 5 shows a fourth embodiment of the present invention (ozone-treated water KM).
FIG. 2 is a configuration explanatory diagram of nO ₄ consumption constant control).

FIG. 6 shows a fifth embodiment (ozone-treated water TH) of the present invention.
FIG. 3 is an explanatory diagram of a configuration of MFP constant control.

FIG. 7 shows a sixth embodiment of the present invention (activated carbon treated water UV).
FIG.

FIG. 8 shows a seventh embodiment of the present invention (activated carbon treated water KM).
FIG. 2 is a configuration explanatory diagram of nO ₄ consumption constant control).

FIG. 9 shows an eighth embodiment of the present invention (activated carbon treated water TH).
FIG. 3 is an explanatory diagram of a configuration of MFP constant control.

[Explanation of symbols]

1 ... raw water tank 2 ... coagulation sedimentation tank 3 ... Previous sand filter 4 ... ozone contact basin 5 ... activated carbon contact basin 6 ... mixing basin 7 ... rear sand filtration basin O ₃ G ... ozone generator O ₃ CT ... injecting ozone concentration meter UVT: Low concentration UV meter WT: Thermometer FT1: Ozone treated raw water flow meter FT2: Injected ozone gas flow meter CTRL: Controller

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/50 540 C02F 1/50 540A 550 550C 550L 560 560B 560Z G01N 21/33 G01N 21/33

Claims (34)

[Claims] 1. A method for controlling an ozone injection rate so that a concentration of dissolved ozone in an ozone contact pond becomes constant when ozone injection treatment is performed on the water to be treated in an ozone contact pond. After the water temperature was measured, the ozone injection rate D (mg / L) was calculated by the following formula using the ultraviolet absorbance A (abs / 50 mm) of the water to be treated, the water temperature T (° C.) of the water to be treated, and the dissolved ozone concentration constant control setting. An ozone injection control method characterized by substituting and determining a value C (mg / L). D = aA + bT + cC + d where a, b, c, and d are constants 2. The ozone injection control method according to claim 1, wherein the ozone injection processing is feed-forward controlled using the ozone injection rate obtained by the formula for determining the ozone injection rate. 3. A method for controlling an ozone injection rate such that a concentration of dissolved ozone in an ozone contact pond becomes constant when ozone injection treatment is performed on the water to be treated in an ozone contact pond. After measuring the water temperature, the UV absorbance A (abs / 50 mm) of the water to be treated, the water temperature T (° C.) and the dissolved ozone concentration constant control set value C (mg /
Wherein the ozone injection rate D (mg / L) determined by substituting L) is corrected by feedback using the dissolved ozone concentration at the outlet of the ozone contact tank and the dissolved ozone concentration constant control set value. . D = aA + bT + cC + d where a, b, c, and d are constants 4. The ozone injection control method according to claim 3, wherein the ozone is injected by feedforward control and feedback control using the ozone injection rate. 5. A method for controlling an ozone injection rate such that the ozone-injected water is subjected to ozone injection treatment in an ozone contact pond so that the ultraviolet absorbance of the ozone-treated water is constant. After the measurement, the UV absorbance A (abs / 50 mm) of the water to be treated, the water temperature T (° C.) of the water to be treated and the dissolved ozone concentration constant control set value C are calculated by the following equations.
(Mg / L) and ozone injection rate D (mg / L)
Using the ultraviolet absorbance of the ozonated water and the ultraviolet absorbance constant control set value of the ozonated water in a feedback manner. D = aA + bT + cC + d where a, b, c, and d are constants 6. The ozone injection control method according to claim 5, wherein an upper limit setting of the concentration of ozone treated water-soluble ozone is added during the feedback correction. 7. The ozone injection control method according to claim 5, wherein ozone is injected by feedforward control and feedback control using the ozone injection rate. 8. When the water to be treated is subjected to ozone injection treatment in an ozone contact pond, potassium permanganate (K) of the ozonized water is treated.
MnO ₄ ) In a method of controlling the ozone injection rate so that the consumption amount is constant, after measuring the ultraviolet absorbance and the water temperature of the water to be treated, the ultraviolet absorbance A (abs / 50 mm) of the water to be treated is calculated by the following formula: Water temperature T (° C) of treated water and dissolved ozone concentration constant control set value C
(Mg / L) and ozone injection rate D (mg / L)
The ozone injection control method characterized by the feedback correction using the ozonated water KMnO ₄ consumption estimate and the KMnO ₄ consumption constant control setting value. D = aA + bT + cC + d where a, b, c, and d are constants 9. The potassium permanganate (KMn)
O ₄ ) The estimated consumption value is calculated by the following KMnO ₄ consumption estimation formula KM
The ozone injection control method according to claim 8, wherein the ozone injection control method is used to calculate the ozone injection. KM = a · A ₂ + b · {1- (A ₂ / A ₁ )} + c, where A ₁ : UV absorbance of water to be treated, A ₂ : UV absorbance of ozone treated water, a, b, c: constants 10. Using the KMnO ₄ consumption estimation formula, the UV absorbance of the water to be treated and the UV absorbance of the ozonated water, which can be measured in real time, use the ozonated water KMnO 4.
Ozone injection control method according to claim 9, wherein the estimating the ₄ consumption in real time. 11. The ozone injection control method according to claim 8, wherein the ozone treated water KMnO ₄ consumption is grasped in real time as an estimated value, and the estimated value is used as a control index for ozone injection. 12. The ozone injection control method according to claim 8, wherein an upper limit setting of the concentration of ozone treated water-soluble ozone is added during the feedback correction. 13. The ozone injection control method according to claim 8, wherein ozone is injected by feedforward control and feedback control using the ozone injection rate. 14. A method for controlling an ozone injection rate such that a trihalomethane generation ability (THMFP) of ozonized water is constant when ozone-injection treatment is performed on the water to be treated in an ozone contact pond. After measuring the UV absorbance and water temperature, the UV absorbance A (abs / 50 mm) of the water to be treated, the water temperature T (° C.) and the dissolved ozone concentration constant control set value C are calculated by the following formulas.
(Mg / L) and ozone injection rate D (mg / L)
Using the estimated value of the ozone-treated water THMFP and the set value of the THMFP constant control, and the feedback correction of D = aA + bT + cC + d where a, b, c, and d are constants 15. The ozone injection control method according to claim 14, wherein the estimated value of the ozone-treated water THMFP is obtained using the following THMFP estimation formula TH. TH = a · A + b · T + c, where A: UV absorbance of ozonated water, T: water temperature of ozonated water, a, b, c: constants 16. The ozone injection control method according to claim 15, wherein the ozone-treated water THMFP is estimated in real time using the THMFP estimation formula, the ultraviolet absorbance of ozone-treated water that can be measured in real time, and the water temperature. 17. The ozone-treated water THMFP is grasped in real time as an estimated value, and the estimated value is used as a control index for ozone injection.
16. The method for controlling ozone injection according to claim 16. 18. The ozone injection control method according to claim 14, wherein an ozone treatment water-soluble ozone concentration upper limit setting is added during the feedback correction. 19. The ozone injection control method according to claim 14, wherein ozone is injected by feedforward control and feedback control using the ozone injection rate. 20. A method of controlling the ozone injection rate so that the ultraviolet absorbance of the activated carbon treated water becomes constant when the treated water is subjected to ozone injection treatment in the ozone contact pond, wherein the ultraviolet absorbance and the water temperature of the treated water are controlled. After the measurement, the UV absorbance A (abs / 50 mm) of the water to be treated, the water temperature T (° C.) of the water to be treated and the dissolved ozone concentration constant control set value C (mg /
An ozone injection control method, wherein the ozone injection rate D (mg / L) determined by substituting L) is feedback-corrected using the ultraviolet ray absorbance of the activated carbon treated water and the ultraviolet ray absorbance constant control set value. 21. The ozone injection control method according to claim 20, wherein an ozone concentration upper limit setting of the ozone treated aqueous solution is added during the feedback correction. 22. The ozone injection control method according to claim 20, wherein the ozone is injected by feedforward control and feedback control using the ozone injection rate. 23. A method for controlling an ozone injection rate such that a consumption amount of potassium permanganate (KMnO ₄ ) of activated carbon treated water becomes constant when ozone injection processing is performed on water to be treated in an ozone contact pond, After measuring the ultraviolet absorbance and the water temperature of the water to be treated, the ultraviolet absorbance A (abs / 50 mm) of the water to be treated, the water temperature T (° C.) and the dissolved ozone concentration constant control set value C are calculated by the following equations.
(Mg / L) and ozone injection rate D (mg / L)
Using the activated carbon treated water KMnO ₄ consumption estimated value and the KMnO ₄ consumption constant control set value. D = aA + bT + cC + d where a, b, c, and d are constants 24. the activated carbon treated water KMnO ₄ consumption estimate, the following activated carbon treated water KMnO ₄ consumption estimation equation KM
24. The method for controlling ozone injection according to claim 23, wherein the method is used to determine the ozone injection. KM1 = a · A1 + b where A1: UV absorbance of activated carbon treated water, a, b: constants And 25. The activated carbon-treated water KMnO ₄ consumption estimation equation, the claims using an ultraviolet absorbance of real-time measurable activated carbon treated water, and estimates the activated carbon treated water KMnO ₄ consumption in real time 25. The method for controlling ozone injection according to claim 24. 26. The ozone injection control method according to claim 23, wherein the KMnO ₄ consumption of the activated carbon treated water is grasped in real time as an estimated value, and the estimated value is used as a control index for ozone injection. 27. The ozone injection control method according to claim 23, wherein an upper limit setting of the ozone-treated water-soluble ozone concentration is added during the feedback correction. 28. The ozone injection control method according to claim 23, wherein ozone is injected by feedforward control and feedback control using the ozone injection rate. 29. A method for controlling an ozone injection rate such that a trihalomethane generating ability (THMFP) of activated carbon treated water becomes constant when ozone injecting treatment of the treated water with an ozone contact pond is performed. After measuring the UV absorbance and water temperature, the UV absorbance A (abs / 50 mm) of the water to be treated, the water temperature T (° C.) and the dissolved ozone concentration constant control set value C are calculated by the following formulas.
(Mg / L) and ozone injection rate D (mg / L)
Using the activated carbon treated water THMFP estimated value and the THMFP constant control set value in a feedback manner. D = aA + bT + cC + d where a, b, c, and d are constants 30. The ozone injection control method according to claim 29, wherein the estimated value of the activated carbon treated water THMFP is determined by using the following activated carbon treated water THMFP estimation formula TH1. TH1 = a · A2 + b · T2 + c, where A2: UV absorbance of activated carbon treated water, T2: temperature of activated carbon treated water, a, b, c: constants 31. The ozone according to claim 30, wherein the activated carbon treated water THMFP is estimated in real time using the activated carbon treated water THMFP estimating formula and the ultraviolet absorbance and water temperature of the activated carbon treated water that can be measured in real time. Injection control method. 32. The activated carbon treated water THMFP is grasped in real time as an estimated value, and the estimated value is used as a control index for ozone injection.
30. The method for controlling ozone injection according to claim 30. 33. The ozone injection control method according to claim 29, wherein an ozone concentration upper limit setting of the ozone treated water-soluble ozone concentration is added during the feedback correction. 34. The ozone injection control method according to claim 29, wherein the ozone is injected by feedforward control and feedback control using the ozone injection rate.