JP2007098287A - Method for controlling operation of water purifying process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling the operation of a water purifying process which can adequately inject a flocculant reflecting the turbidity properties of raw water from low turbidity up to ultrahigh turbidity. <P>SOLUTION: The turbidity concentration of the raw water is measured by a turbidimeter 23, the flocculant injection ratio per unit volume to the measured value of the turbidity concentration is operated from the predetermined relation between the turbidity concentration and the flocculant injection ratio, and the flocculant injection dose is calculated by multiplication of the flocculant injection ratio by a raw water flow rate after measuring the raw water flow rate by a flow meter 21. Thereby, an injection device 8 which injects the flocculant to a settling pond 2 is controlled by a controller 34. In comparison with the measured value of the turbidity or the turbidity concentration and the predetermined value, the flocculant injection ratio to the turbidimeter measured value is operated on the relation between the turbidity and the flocculant injection ratio, or the relation between the turbidity concentration and the flocculant injection ratio. Thereby, the flocculant injection dose is controlled by changing the operation index at the low, high and ultrahigh turbidities. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an operation management method of a water purification process in which a flocculant is appropriately injected in response to the turbidity of raw water taken to obtain purified water with stable water quality.

  At the water purification plant, purified water is obtained by coagulating and injecting a flocculant to bind and agglomerate suspended solids in the raw water (hereinafter referred to as turbidity) and aggregating and precipitating to remove the precipitate. Yes. In water treatment plants, turbidity management using turbidity as an index is widely adopted regardless of domestic and overseas. When surface water such as rivers and lakes is used as raw water, the turbidity of the raw water, that is, the type and particle size of the turbidity, are factors such as terrain and geology of the basin, climate and weather conditions, land use form, and season. Fluctuates due to Because turbidity also varies greatly due to these factors, in order to obtain purified water below the set turbidity, it is necessary to properly control the amount of flocculant injected, and proper control of the amount of flocculant injected is required for water treatment plants. Has become one of the important daily tasks.

  When the injection amount of the flocculant is insufficient, the combined aggregates (hereinafter referred to as floc) with turbidity do not grow, so that they do not settle sufficiently, increasing the burden of the subsequent filtration process, and not being trapped. Water quality deteriorates because the quality is mixed with purified water. When the injection amount of the flocculant becomes excessive, a swollen floc is formed, the aggregation is inhibited by electrical repulsion, and it becomes difficult to settle. Problems arise. For these reasons, various flocculant injection methods corresponding to changes in the turbidity of raw water have been proposed.

  For example, as described in [Non-Patent Document 1], based on a flocculant injection formula created in consideration of factors that cause floc formation such as alkalinity, pH, and water temperature in the turbidity of raw water, the flocculant There is a way to manipulate the amount of injection.

  In [Patent Document 1], the formula for calculating the injection rate of the polymer flocculant with respect to the raw water turbidity is set such that the injection rate of the polymer flocculant is proportional to the injection rate of the inorganic flocculant and at a predetermined upper limit injection rate. The calculation formula A is set to the peak, and the injection rate of the polymer flocculant is set so that the injection rate of the polymer flocculant becomes the upper limit injection rate when the injection rate of the inorganic flocculant is the maximum injection rate. Two formulas are set up to be proportional to the calculation formula B, and either one of the two formulas is selected according to the magnitude of the fluctuation of the raw water turbidity and the current raw water turbidity, and the polymer flocculant is injected. A flocculant injection control method for controlling the rate is disclosed.

  [Patent Document 2] measures the turbidity or chromaticity of a collected sample, calculates the optimum addition amount of the flocculant based on the measured value, and controls the flocculant injection pump to inject the flocculant. A flocculant injection control method that optimally controls the amount is disclosed.

  In [Patent Document 3], the floc on the outlet side of the floc formation pond is imaged, the image is binarized by the obtained image recognition means, the floc is recognized, the number of flocs is calculated from the recognized data, A flocculant injection control device is disclosed in which when the number of flocs obtained is equal to or greater than a target value, the pump is controlled by the injection control means so that the flocculant injection amount is smaller than the current injection amount.

  In [Patent Document 4], primary flocculant injection means is connected to a feed line that feeds raw water from water intake means, and the raw water into which the primary flocculant has been injected is turbidity of 100 to 150 degrees or less in a sand basin. The secondary flocculant injecting means is connected to the feed line that feeds the secondary raw water, and the secondary raw water into which the secondary flocculant has been injected is treated with a moving bed sand filtration device. A raw water treatment apparatus for obtaining treated water having a turbidity of 5 is disclosed.

  In [Patent Document 5], a particle counter that measures the diameter of the fine particles in water and the number corresponding to the diameter, and data analysis that determines the optimum flocculant injection amount by inputting data obtained by the particle counter And a coagulant injection control method for controlling the injection amount of the coagulant according to the coagulant injection amount obtained by the data analysis unit.

  [Patent Document 6] includes a flow meter for measuring the inflow of raw inflow water, a turbidimeter for measuring the turbidity of inflow raw water, a chemical injection pump for injecting a flocculant into the inflow raw water, and a chemical injection pump. Input the measurement signals of pH meter, flow meter, turbidity meter, conductivity meter, flow current meter and pH meter to measure the pH value of coagulant injection mixed water after flocculant injection, and input signal Based on the above, there is disclosed a water purifying flocculant automatic injection device provided with pump means for controlling the amount of flocculant to be injected in accordance with fluctuations in the properties of inflow raw water.

  According to [Patent Document 7], the seasonal variation parameter of the intake source of the treated water such as the river flow rate and the amount of water and the measured value of the charge state at the time of the optimal aggregation corresponding to the seasonal variation parameter are There is disclosed a flocculant injection control system that sets a target value of a corresponding charge state and adjusts the amount of flocculant injected so that the measured value of the charge state is maintained at the target value.

JP 2002-66209 A JP-A-5-146608 JP-A-5-285308 Japanese Unexamined Patent Publication No. 2000-300908 JP-A-8-126802 JP 2002-239307 A JP 2003-200195 A Japan Water Works Association “Water Supply Management Guidelines” (1998 edition)

  Various substances are suspended in the raw water, including clay substances, organic substances, various microorganisms, animal and plant plankton, and substances insolubilized by physical and chemical changes such as metallic ions and inorganic ions. These are collectively called turbidity. The suspended matter is optically measured by transmitted light, scattered light, surface scattered light, or a combination thereof. The clayey substance, which is the main component of the turbidity, is negatively charged. By injecting a flocculant containing a positively charged metal, it becomes possible to settle due to gravity by binding and agglomeration. Can be removed.

  The reaction caused by injecting the flocculant is not only a clay-like substance, but also a complex reaction that is affected by a variety of factors such as other turbid components, soluble metals, inorganic ions, and water temperature. Not.

  Although the method described in [Non-Patent Document 1] deals with fluctuations in the quality of raw water by feedforward control, it treats the nature of turbidity as universal, so it is particularly characterized during rainy days. There is a problem that it is difficult to continuously maintain an appropriate injection rate, such as being unable to cope with changes.

  In addition, the technique of [Patent Document 1] prepares different injection formulas depending on, for example, low turbidity (up to several tens of degrees) during fine weather and high turbidity (several tens to several hundred degrees) during rainfall. Although it can be operated, the discontinuous injection rate is near the boundary between low turbidity and high turbidity, so there is a problem that proper coagulation sedimentation does not occur near the boundary, and during rain and rain There is a problem that it cannot respond to the change in turbidity that is different after stopping, and it cannot cope with the turbidity of raw water that reaches tens of thousands of degrees in heavy rain or basin conditions.

  In the techniques of [Patent Document 2] and [Patent Document 3], the turbidity of coagulated sediment treated water and the floc shape feature amount after injecting the flocculant are measured, and the injection rate is manipulated by feeding back the deviation from the target value. By doing so, it is possible to reflect the difference in floc formation state and coagulation sedimentation characteristics due to changes in turbid properties, but the quantitative relationship between the turbidity of coagulated sediment treated water and the feature quantity of floc shape has been elucidated. In other words, the turbidity of the treated water increases even when the flocculant is excessive or insufficient, so the turbidity measurement value of the treated water increases or decreases the injection rate of the flocculant. There is a problem that judgment cannot be made.

  In the technology of [Patent Document 4], coagulant is injected into the raw water supply line to the water purification plant in advance in response to the raw water of ultra high turbidity (several hundred to several thousand degrees) Although the turbidity of the injection target water can be reduced within a predetermined range, the nature of the turbidity is not considered, and it is difficult to continuously maintain an appropriate injection rate.

  The technique of [Patent Document 5] is based on the premise that the number of particles can be accurately measured. However, there is a problem that it is difficult to accurately measure the number of particles of high turbidity raw water that is several thousand degrees or more. In addition, according to the experiments of the present inventors about the case where the raw water having a high turbidity is precipitated by injecting the flocculant after temporarily storing the raw water, the amount of the flocculant for coagulating and precipitating the unit turbid mass is It was shown that even if the particle size range is the same, it changes. For this reason, the technique of [Patent Document 5] has a problem that it is difficult to apply to the process of raw water with high turbidity.

  In the technique of [Patent Document 6], the flocculant injection mixed water after the flocculant injection is controlled so that the amount of the flocculant injected according to the change in the properties of the influent raw water is controlled. It is difficult to maintain an appropriate injection rate continuously without considering the properties.

  The technique of [Patent Document 7] sets the target of the charging state according to the season corresponding to the seasonal variation parameter, but does not consider the properties of the turbidity and continuously provides an appropriate injection rate. It is difficult to maintain.

  By the way, the water purification plant is operated continuously throughout the year, and the turbidity and water quality of the raw water vary greatly due to various factors. In this way, water treatment plants require continuous operation and operation management that takes into account the ever-changing turbidity properties.To this end, it is practical, simple, easy to maintain, and highly reliable with a highly reliable measuring instrument. It is desired to control the injection of a flocculant that can grasp the property and can cope with low turbidity of several degrees to ultra high turbidity of several thousand degrees.

  A first object of the present invention is to provide an operation management method for a water purification process that can inject a coagulant amount appropriately from low turbidity to ultra-high turbidity reflecting the turbidity of raw water.

  The second object of the present invention is to provide a water purification process operation management method capable of injecting an appropriate amount of coagulant into sudden turbidity change and turbidity change after rain, and supplying stable and high quality coagulation sedimentation water. It is to provide.

  In order to achieve the above object, the present invention measures the turbidity concentration with a turbidity concentration meter installed in the raw water intake pipe connected to the chemical mixing pond, and stores the turbidity concentration and unit stored in advance in the calculator. The flocculant injection rate per unit volume corresponding to the turbidity concentration was calculated from the relational expression with the flocculant injection rate per volume, and the raw water flow rate measured by the flow meter installed in the raw water intake pipe was calculated. Calculate the coagulant injection amount based on the coagulant injection rate per unit volume, and control the injection equipment with the controller so that the coagulant injected into the chemical mixing basin is adjusted to the calculated coagulant injection amount. Is.

  Also, the measured turbidity or turbidity concentration is compared with the set value of turbidity or the set value of turbidity concentration, the relational expression between turbidity concentration and the flocculant injection rate per unit volume, turbidity and unit The relational expression with the flocculant injection rate per volume is switched.

  Calculate the turbidity coefficient from the turbidity and turbidity concentration, calculate the corrected injection coefficient corresponding to the turbidity coefficient calculated by the relational expression between the turbidity coefficient and the corrected injection coefficient, and calculate the corrected flocculant injection rate. It is what you want.

  Further, the flocculant injection rate is corrected based on the deviation deviation between the turbidity and the turbidity target value.

  ADVANTAGE OF THE INVENTION According to this invention, even if the turbidity property of raw | natural water changes in high and ultra-high turbidity, there exists an effect which can inject | pour an appropriate amount of coagulant | flocculants and can provide the stable high quality coagulation sedimentation treated water.

  Provided is a water purification process operation management method capable of appropriately injecting a flocculant from a low turbidity to an ultra-high turbidity by determining the amount of the flocculant injected based on the turbidity concentration. Embodiments of the present invention will be described below with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a water purification process.

As shown in FIG. 1, a flow meter 21 and a turbidity concentration meter 23 are sequentially connected to the raw water intake pipe 1 connected to the chemical mixing pond 2. The flow meter 21 is directly connected to the calculator 33, the turbidity concentration meter 23 is connected to a calculator 32 that calculates the coagulant injection rate, and the calculator 32 is connected to the calculator 33. Here, since flowmeters, turbidity meters, and turbidity concentration meters that have been put into practical use can be used, highly reliable coagulant injection management can be realized.

  The flocculant storage tank 7 is connected to a flocculant injection facility 8, and further connected to a flocculant injection pipe 9 provided in the chemical mixing basin 2 via a flow meter 24. The computing unit 33 is connected to the controller 34, and the controller 34 is connected to the injection facility 8 while being connected to a signal line so as to feed back the measurement value of the flow meter 24. The injection facility 8 is composed of a valve or a variable flow rate pump.

  A stirrer 201 is installed in the chemical mixing pond 2, and the chemical mixing basin 2 is connected to the flock formation pond 3 in which the stirrer 301 is installed. The floc formation pond 3 is connected to a settling basin 4, a discharge pipe 6 for discharging waste mud is provided at the bottom of the settling basin 4, and the treated water from which turbidity has been removed is formed above the settling basin 4. A water intake pipe 5 for taking out (also referred to as a precipitate supernatant) is provided.

When the raw water containing turbidity flows from the raw water intake pipe 1 into the chemical mixing pond 2, the flow rate is measured by the flow meter 21, and the turbid concentration meter 23 measures the turbid concentration SSi. The measured turbidity concentration SSi is input to the calculator 32, and the coagulant injection rate Cp with respect to the turbidity concentration SSi is calculated by Equation 1. Here, a and k are constants.
(Equation 1)
^{Cp = a · SSi k (1} )
2 and 3 show that the present inventors changed the initial turbidity in the range of 200 to 5000 degrees (turbidity concentration of 1000 to 25000 mg / L), and the flocculating agent has a flocculation precipitate supernatant turbidity of 1 degree. It is the experimental result which calculated | required the injection rate. FIG. 2 shows the turbidity concentration SS on the horizontal axis and the flocculant injection rate Cp on the vertical axis. FIG. 3 shows the turbidity on the horizontal axis and the flocculant injection rate Cp on the vertical axis. It is organized for.

  As can be seen from FIGS. 2 and 3, when the turbidity concentration SS is arranged on the horizontal axis, each experimental point is approximated by one curve and is not affected by the turbidity property, and can be expressed by the following equation (1). However, when the turbidity is arranged on the horizontal axis, the experimental point cannot be approximated by one curve, and when the turbidity property changes, an exponential expression with different coefficients is obtained. That is, in the case of high turbidity and ultra-high turbidity, if the turbidity properties are the same, it can be expressed by a specific exponential expression, but in the approximate expression using turbidity as an index, the turbidity properties cause excess and deficiency of the flocculant. There is a case. For this reason, in this embodiment, Formula 1 shown in FIG. 2 using the turbidity concentration SS as an index is applied, and an appropriate flocculant can be injected.

  The computing unit 33 multiplies the coagulant injection rate Cp per unit volume determined by the computing unit 32, the raw water flow rate Q measured by the flow meter 21, the coagulant injection rate Cp and the raw water flow rate Q. The coagulant injection amount Qp is calculated. The controller 34 adjusts the flocculant injection facility 8 based on the deviation between the calculated flocculant injection amount Qp and the flocculant injection operation amount Qp ′ measured by the flow meter 24.

  As the flocculant injected from the flocculant injection facility 8, an inorganic system or a polymer system such as aluminum or iron is used. In the chemical mixing pond 2, the flocculant is uniformly mixed with the raw water by the stirrer 201, and the suspended matter and the flocculant are combined to form a micro floc that becomes the core of the floc. The micro floc grows by being stirred by the stirrer 301 operated at a slower speed than the stirrer 201 in the floc formation pond 3 and becomes a coarse floc. The coarse floc settles in the sedimentation basin 4 and is sent from the intake pipe 5 to the subsequent treatment facility as the supernatant from which the turbidity has been removed, that is, the treated water of the coagulation sedimentation basin, and is subjected to filtration and sterilization treatment. After that, it is distributed as purified water. The floc settled and separated in the settling basin 4 is discharged out of the system as a waste liquid.

  As described above, the flocculant injection coefficient corresponding to the turbidity of the raw water can be set, and the amount of flocculant injected is appropriately controlled, so that it is possible to provide good sedimentation basin treated water.

  A second embodiment of the present invention will be described with reference to FIG. The present embodiment is configured in the same manner as in the first embodiment, but in this embodiment, the raw water intake pipe 1 is provided with a turbidimeter 22, and the turbidimeter 22 and the turbidity concentration meter 23 are connected to a determiner 31. The determination unit 31 is connected to the arithmetic unit 32.

The turbidity Tui of the raw water measured by the densitometer 22 and the turbidity concentration SSi measured by the turbidity densitometer 23 are input to the determiner 31.

  A turbidity setting value Mt or a turbidity concentration setting value Ms is input to the determination unit 31 in advance, and the measured turbidity Tui <turbidity setting value Mt or turbidity concentration SSi <turbidity. In the case of the concentration set value Ms, a signal for calculating the flocculant injection rate is output to the calculator 32 using turbidity as an index. When the measured turbidity Tui ≧ turbidity setting value Mt or turbidity concentration SSi ≧ turbidity concentration setting value Ms, a signal for calculating the flocculant injection rate using the turbidity concentration as an index is supplied to the calculator 32. Output. Here, the set value Mt of turbidity or the set value Ms of turbidity concentration can be set according to the water source state, for example, set to 200 degrees and 1000 mg / L.

  In the calculator 32, when a signal for calculating the coagulant injection rate is input using the turbidity as an index, the coagulant injection rate Cp is calculated by a mathematical expression using the turbidity input in advance as a variable, and the turbidity concentration is calculated. When a signal for calculating the coagulant injection rate is input as an index, the coagulant injection rate Cp is calculated by Equation 1 and output to the calculator 33. The calculator 33 and the controller 34 perform the same calculation as in the first embodiment and control the flocculant injection facility 8.

  The turbid state, that is, the substance forming the turbidity, changes with low turbidity, high turbidity, and extremely high turbidity. In the case of low turbidity, the ratio of other substances is higher than that of clay-like substances, and various substances affect turbidity, so turbidity is used as an index. High turbidity and ultra-high turbidity are due to the influence of sediment and sediment in the basin due to rainfall and water flow, and most of the turbidity is occupied by clayey substances. In the case of high turbidity or ultra-high turbidity in which clayey substances are mainly turbid, the flocculant is injected using the turbidity concentration not affected by the particle size as an index.

  Thus, low turbidity is turbidity, and high turbidity and ultra-high turbidity can maintain appropriate coagulation sedimentation by using turbidity concentration as an index.

  A third embodiment of the present invention will be described with reference to FIGS. The present embodiment is configured in the same manner as in the second embodiment, but in this embodiment, a computing unit 35 for computing turbidity properties is provided, and the computing unit 35 is connected to a determination unit 31 and a computing unit 32. Yes.

  The turbidity Tui measured by the turbidimeter 22 and the turbidity concentration SSi measured by the turbidimeter 23 are input to the determiner 31 and input to the calculator 35 via the determiner 31. The calculator 35 calculates the turbidity coefficient D = turbidity concentration SSi / turbidity Tui and outputs it to the calculator 32.

  In the determiner 31, the coagulant injection rate Cp is calculated and output to the calculator 32 as in the second embodiment. The calculator 32 corrects the coagulant injection rate Cp based on the turbidity coefficient D calculated by the calculator 35.

FIG. 6 is a diagram showing the relationship between the turbidity coefficient D and the corrected injection coefficient f. The corrected injection coefficient f is set based on the deviation from the reference value of the turbidity coefficient D, and the corrected flocculant injection rate Cp ^* is agglomerated. It is calculated by the agent injection rate Cp + corrected injection coefficient f + turbidity concentration SSi and output to the calculator 33. The calculator 33 and the controller 34 perform the same calculation as in the first embodiment and control the flocculant injection facility 8.

  The turbidity coefficient D has a positive correlation with the particle size of the turbidity, and if the turbidity coefficient D is small, the particle size is small and there are many turbidities that are difficult to precipitate. By this correction, when the particle size is small, the injection rate is increased to enhance the coagulation precipitation effect, and conversely, when the particle size is large, it is determined that the turbidity tends to settle, and the coagulant can be reduced.

  According to experiments, the correction injection coefficient f is affected by the turbid concentration SSi, and may be a function of the turbid concentration SSi. Further, the correction using the turbidity coefficient D can be similarly performed when turbidity is used as an index.

A fourth embodiment of the present invention will be described with reference to FIG. The present embodiment is configured in the same manner as in the first embodiment, but in this embodiment, a turbidimeter 22B is installed in the intake pipe 5 connected to the settling basin 4 and the measured value of the turbidimeter 22B is fed back. The injection rate corrector 36 is provided, and the injection rate corrector 36 is connected to the calculator 32 and the calculator 33.

The turbidity Tuo of the treated water flowing through the intake pipe 5 is measured by the turbidimeter 22B, and the turbidity Tuo is input to the injection rate corrector 36 to correct the coagulant injection rate Cp calculated by the calculator 32. The turbidity target value Tuo ^* of the treated water is input to the calculator 32, and the turbidity deviation ΔTu = turbidity Tuo−turbidity target value Tuo ^* is obtained and multiplied by the correction coefficient θ to correct the injection rate ΔCp = θ. ΔTu is calculated and added to the coagulant injection rate Cp to obtain the coagulant injection rate Cp ^*, which is output to the calculator 33.

  With this correction, the turbidity of the coagulation sedimentation treated water can be maintained at the target value even when the turbidity property or the raw water liquid quality changes to affect the coagulation sedimentation characteristics.

  In the above description, the relationship between the turbidity concentration or the turbidity and the coagulant injection rate has been described assuming that the turbidity of the coagulated sediment treated water is 1 degree. Can be set according to the intended use of water.

  The present invention is a process for producing industrial water in addition to a general water purification process composed of a flocculant-mixing basin, a flock formation pond and a sedimentation basin, and a water purification system having sand filtration or membrane-based filtration equipment at the subsequent stage of the sedimentation basin. It can also be applied to water purification processes that are equipped with advanced treatment equipment such as ozone treatment in the latter part of the process.

  In addition, by inputting the turbidity concentration or turbidity and the coagulant injection rate, and having the function of calculating the characteristic formula in the coagulant injection rate calculator, the operation management reflecting the jar test result can be performed.

It is a block diagram of the water purification process which is Example 1 of this invention. It is a figure which shows the relationship between the turbidity density | concentration and the coagulant injection rate in a present Example. It is a figure which shows the relationship between the turbidity supplemented by a present Example and the coagulant | flocculant injection rate. It is a block diagram of the water purification process which is Example 2 of this invention. It is a block diagram of the water purification process which is Example 3 of this invention. It is a figure explaining an example of correction | amendment injection | pouring in a present Example. It is a block diagram of the water purification process which is Example 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Raw water intake pipe, 2 ... Chemical mixing pond, 3 ... Flock formation pond, 4 ... Sedimentation basin, 5 ... Intake pipe, 7 ... Discharge pipe, 7 ... Storage tank, 8 ... Injection equipment, 9 ... Injection pipe, 21, 24 ... Flow meter, 22, 22B ... Turbidimeter, 23 ... Turbidimeter, 31 ... Determinator, 32, 33, 35 ... Calculator, 34 ... Controller, 36 ... Injection rate corrector.

Claims (5)

  The turbidity concentration is measured by the turbidity concentration meter installed in the raw water intake pipe connected to the chemical mixing pond, and the relational expression between the turbidity concentration stored in advance in the calculator and the flocculant injection rate per unit volume is used. Calculate the flocculant injection rate per unit volume corresponding to the turbidity concentration, and flocculate by the raw water flow rate measured by the flow meter installed in the raw water intake pipe and the calculated flocculant injection rate per unit volume An operation management method for a water purification process that calculates an agent injection amount and controls an injection facility with a controller to adjust a coagulant to be injected into the chemical mixing basin to the calculated coagulant injection amount.   The turbidity and turbidity concentration are measured with a turbidimeter and turbidity concentration meter installed in the raw water intake pipe connected to the chemical mixing pond, and the measured turbidity or turbidity concentration is a set value of turbidity. Alternatively, when the turbidity concentration is equal to or higher than the set value, the flocculant injection per unit volume corresponding to the turbidity concentration is calculated by the relational expression between the turbidity concentration stored in advance in the calculator and the flocculant injection rate per unit volume. Calculate the rate, calculate the coagulant injection amount from the raw water flow rate measured by the flow meter installed in the raw water intake pipe and the calculated coagulant injection rate per unit volume, and control the injection equipment by the controller Then, the operation control method of the water purification process is adjusted so that the coagulant injected into the chemical mixing pond is the calculated coagulant injection amount.   The turbidity and turbidity concentration are measured with a turbidimeter and turbidity concentration meter installed in the raw water intake pipe connected to the chemical mixing pond, and the measured turbidity or turbidity concentration is a set value of turbidity. Alternatively, if the turbidity concentration is smaller than the set value, the flocculant injection rate per unit volume corresponding to the turbidity concentration is determined by the relationship between the turbidity stored in advance in the calculator and the flocculant injection rate per unit volume. Calculate the flocculant injection amount from the raw water flow rate measured by the flow meter installed in the raw water intake pipe and the calculated flocculant injection rate per unit volume, and control the injection equipment by the controller An operation management method for a water purification process in which the coagulant injected into the chemical mixing pond is adjusted to be the calculated coagulant injection amount.   Calculate a turbidity coefficient from the turbidity and turbidity concentration, calculate a correction injection coefficient corresponding to the turbidity coefficient calculated by the relational expression between the turbidity coefficient stored in the calculator and the correction injection coefficient, Calculate the corrected coagulant injection rate by calculating the corrected coagulant injection rate, the coagulant injection rate per unit volume, and the sum of the turbidity concentration to obtain the corrected coagulant injection rate. The operation management method of the water purification process of Claim 2 or 3. A sedimentation basin is connected to the chemical mixing pond via a flock formation pond, and the deviation between the turbidity measured by the turbidimeter installed in the intake pipe of the sedimentation basin and the turbidity target value is calculated. And the operation management method of the water purification process of Claim 1 which correct | amends the said coagulant | flocculant injection rate based on this calculated deviation.

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