JPH0433482B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a chemical injection control method for a coagulation sedimentation treatment device, and in particular, (i) fuzzy set regarding raw water turbidity or the design value ratio of raw water turbidity and the amount of change or change in raw water turbidity; Measured value of raw water turbidity or design of raw water turbidity determined from the measured value based on the first fuzzy rule established between the fuzzy set regarding the ratio and the fuzzy set regarding the amount of change or change rate of the inorganic flocculant injection rate Calculate the amount or rate of change in the inorganic flocculant injection rate by fuzzy reasoning from the calculated value of the value ratio and the calculated value of the amount of change or rate of change in raw water turbidity obtained from the measured value of raw water turbidity, and (ii) A second fuzzy rule established between a fuzzy set regarding the change rate or change rate of the inorganic flocculant injection rate, a fuzzy set regarding the treated water turbidity, and a fuzzy set regarding the change amount or change rate of the organic polymer flocculant injection rate Based on the inorganic flocculant injection rate, the change amount or change rate is determined by fuzzy reasoning from the inferred value of the change amount or change rate of the inorganic flocculant injection rate and the measured value of treated water turbidity, and (iii) the inorganic flocculation rate is determined by fuzzy reasoning. The current value of the inorganic flocculant injection rate and the current value of the organic polymer flocculant injection rate according to the amount of change in the agent injection rate or the inferred value of the change rate and the amount of change or inferred value of the change rate of the organic polymer flocculant injection rate. Change the values and
(iv) Change the injection amount of the inorganic coagulant and the organic polymer coagulant according to the changed value of the inorganic coagulant injection rate, the changed value of the organic polymer coagulant injection rate, and the measured value of the raw water flow rate. The present invention relates to a chemical injection control method for a coagulation and sedimentation treatment apparatus that injects an inorganic flocculant and an organic polymer flocculant into raw water. [Prior Art] Conventionally, the chemical injection control method for this type of coagulation-sedimentation processing equipment involves separating raw water and adding and injecting reagents with injection rates of an inorganic flocculant and an organic polymer flocculant set appropriately. A method in which the optimal injection rate of inorganic flocculant and organic polymer flocculant is determined by performing a coagulation-sedimentation test in a batch manner, and the inorganic flocculant and organic polymer flocculant are injected into raw water based on this. was proposed. [Problems to be solved] However, the conventional chemical injection control method for coagulation and sedimentation processing equipment has the drawbacks of (i) requiring 30 to 90 minutes for each coagulation and sedimentation test to determine the injection rate; , and (ii) skilled operators to select the most suitable inorganic flocculant or organic polymer flocculant or to determine the sedimentation rate of aggregates (i.e., flocs) formed by injection of the inorganic flocculant or organic polymer flocculant. As a result, (iii)
It had the disadvantage of not adapting to automation. Therefore, the present invention aims to provide a chemical injection control method for a coagulation sedimentation treatment apparatus that eliminates these drawbacks. (2) Structure of the invention [Means for solving the problems] The means for solving the problems provided by the present invention are as follows:
``Chemical injection control method for a coagulation and sedimentation treatment device in which an inorganic flocculant and an organic polymer flocculant are injected into raw water in order to flocculate suspended matter in raw water, remove sediment, and then discharge it as treated water. (a) The first step is to measure the raw water flow rate using a raw water flow meter.
and (b) a second step of measuring raw water turbidity using a raw water turbidity meter.
(c) A third step of measuring the turbidity of the treated water using a treated water turbidity meter; (d) Determining the raw water turbidity from the measured value of the raw water turbidity measured in the second step. a fourth step of calculating the amount of change or rate of change, and (e) fuzzy set regarding raw water turbidity, fuzzy set regarding amount of change or rate of change in raw water turbidity, and fuzzy set regarding amount of change or rate of change in inorganic flocculant injection rate; Based on the first fuzzy rule established between the set, the amount of change or rate of change in the raw water turbidity measured in the second step and the raw water turbidity calculated in the fourth step. a fifth step of determining the amount or rate of change in the inorganic flocculant injection rate from the calculated value by fuzzy reasoning; (f) fuzzy set and turbidity of the treated water regarding the amount or rate of change in the inorganic flocculant injection rate; The amount of change in the inorganic flocculant injection rate determined in the fifth step based on the second fuzzy rule established between the fuzzy set regarding the degree of change and the fuzzy set regarding the change amount or change rate of the organic polymer flocculant injection rate Alternatively, a sixth step of determining the change amount or change rate of the organic polymer flocculant injection rate by fuzzy reasoning from the inferred value of the change rate and the measured value of the treated water turbidity measured in the third step. Injecting the inorganic flocculant according to the amount of change in the inorganic flocculant injection rate or the inferred value of the change rate determined in the fifth step and the measured value of the raw water flow rate measured in the first step a seventh step of injecting an inorganic flocculant into the raw water by changing the amount of the inorganic flocculant; 1
an eighth step of changing the amount of organic polymer flocculant to be injected according to the measured value of the raw water flow rate measured in the step of and injecting the organic polymer flocculant into the raw water; A chemical injection control method for a coagulation sedimentation treatment device characterized by the following. In addition, the solution to the problem provided by the present invention is as follows: ``In order to flocculate the suspended solids in the raw water, remove the precipitate, and then discharge it as treated water, an inorganic flocculant and an organic polymer flocculant are added to the raw water. In a chemical injection control method for a coagulation-sedimentation treatment apparatus in which:
and (b) a second step of measuring raw water turbidity using a raw water turbidity meter.
(c) A third step of measuring the turbidity of the treated water using a treated water turbidity meter; (d) The measured value of the raw water turbidity measured in the second step is determined as the raw water turbidity. (e) calculating the amount of change or change in raw water turbidity from the measured value of raw water turbidity measured in the second step; (f) a fuzzy set regarding the design value ratio of raw water turbidity, a fuzzy set regarding the change amount or rate of change in raw water turbidity, and a fuzzy set regarding the change amount or change rate of the inorganic flocculant injection rate; Based on the first fuzzy rule established between the set, the calculated value of the design value ratio of the raw water turbidity calculated in the fourth step and the amount of change in the raw water turbidity calculated in the fifth step or a sixth step of calculating the change amount or change rate of the inorganic flocculant injection rate by fuzzy inference from the calculated value of the change rate; and (g) fuzzy set regarding the change amount or change rate of the inorganic flocculant injection rate. Inorganic flocculant injection determined in the sixth step based on the second fuzzy rule established between the fuzzy set regarding the treated water turbidity and the fuzzy set regarding the change amount or change rate of the organic polymer flocculant injection rate. From the inferred value of the rate change or rate of change and the measured value of the turbidity of the treated water measured in the third step, use fuzzy reasoning to determine the rate of change or rate of change in the organic polymer flocculant injection rate. (h) according to the amount of change in the inorganic flocculant injection rate or the inferred value of the change rate obtained in the sixth step and the measured value of the raw water flow rate measured in the first step; an eighth step of changing the injection amount of the inorganic coagulant and injecting the inorganic coagulant into the raw water; The inferred value of the rate and the first
and a ninth step of injecting the organic polymer flocculant into the raw water by changing the injection amount of the organic polymer flocculant according to the measured value of the raw water flow rate measured in the step of ``Characteristic chemical injection control method for coagulation sedimentation processing equipment.'' [Function] The chemical injection control method of the coagulation-sedimentation treatment apparatus according to the present invention includes adding an inorganic coagulant and an organic polymer to raw water in order to flocculate suspended solids in the raw water, remove the precipitate, and then discharge it as treated water. A chemical injection control method for a coagulation sedimentation treatment device in which a coagulant is injected, the method comprising:
It is characterized by comprising the first to eighth steps listed in items (a) to (h) in the first part of the [Means for solving problems] column, so (i) applying an inorganic flocculant to raw water and It has the function of making it possible to automate the injection of organic polymer flocculant, and in turn (ii) the function of changing the injection amount of inorganic flocculant and organic polymer flocculant in real time in response to changes in the flow rate of raw water and its water quality. . As a result, (iii) the amount of injected inorganic flocculant and organic polymer flocculant is reduced, and (iv) the coagulation and sedimentation treatment of raw water is made more precise. In addition, another chemical injection control method of the coagulation-sedimentation treatment apparatus according to the present invention also includes the following steps:
A chemical injection control method for a coagulation-sedimentation treatment device in which an inorganic flocculant and an organic polymer flocculant are injected into raw water, and (a) ~
Since it is characterized by comprising the first to ninth steps listed in item (i), similarly, the above-mentioned (i) to (iv)
It has the effect of [Implementation] Next, the chemical injection control method of the coagulation-sedimentation treatment apparatus according to the present invention will be specifically explained by citing preferred examples thereof. However, the examples described below are described to facilitate or accelerate understanding of the present invention, and are not described to limit the present invention. In other words, each element disclosed in the embodiments described below includes all design changes and equivalent substitutions that fall within the spirit and technical scope of the present invention. FIG. 1 is a conceptual diagram showing a coagulation-sedimentation processing apparatus in which chemical injection control is executed according to an embodiment of the chemical injection control method for a coagulation-sedimentation processing apparatus according to the present invention. FIGS. 2 a to 2 c are first operation explanatory diagrams for explaining one embodiment of the chemical injection control method of the coagulation-sedimentation treatment apparatus according to the present invention. A fuzzy set A consisting of triangular membership functions L _A , M _A , H _A created with respect to turbidity, and a fuzzy set consisting of triangular membership functions L _B , M _B , H _B created regarding the rate of change S of raw water turbidity. B, and a fuzzy set C consisting of triangular membership functions N _C , N M _C , ZO _C , P M _C , and P B _C created with respect to the change rate P of the inorganic flocculant injection rate are exemplarily shown. 3a to 3c are second operation explanatory diagrams for explaining one embodiment of the chemical injection control method of the coagulation sedimentation processing apparatus according to the present invention, and each shows a change rate of the inorganic coagulant injection rate. Fuzzy set D consisting of triangular membership functions L _D , M _D , _HD created for P, and fuzzy set E consisting of triangular membership functions L _E , M _E , H _E created for treated water turbidity Q. and a fuzzy set F consisting of triangular membership functions NB _F , NM _F , ZO _F , PM _F , and PB _F created with respect to the change rate R of the organic polymer flocculant injection rate. FIGS. 4 a 1 to ₄ e are third operation explanatory diagrams for explaining one embodiment of the chemical injection control method of the coagulation-sedimentation treatment apparatus according to the present invention, and are the same as those shown in FIGS. 2 a to c. This figure exemplarily shows how to determine the change rate P of the inorganic flocculant injection rate by executing fuzzy inference based on the fuzzy rules f ₁₁ , ~, f ₁₉ shown in Table 1 regarding the fuzzy sets A, ~, C. . FIGS. 5 a 1 to ₅ e are fourth operation explanatory diagrams for explaining one embodiment of the chemical injection control method of the coagulation-sedimentation treatment apparatus according to the present invention, and are the same as those shown in FIGS. 3 a to c. The method of determining the change rate R of the organic polymer flocculant injection rate by executing fuzzy inference based on the fuzzy rules f ₂₁ , ~, f ₂₉ shown in Table 2 regarding the fuzzy sets D, ~, F is exemplified. ing. First, with reference to FIG. 1, an embodiment of the chemical injection control method for a flocculation and sedimentation treatment apparatus according to the present invention will be described in detail while explaining the configuration of the flocculation and sedimentation treatment apparatus that executes the method. Here, to simplify the explanation, we will use the hydrogen ion concentration index, or PH
It is assumed that this adjustment is not performed, but if this is necessary for the formation of aggregates, a PH detector or the like may be appropriately installed to detect it, and adjustment may be made in a well-known manner. Reference numeral 10 denotes a coagulation-sedimentation processing device in which chemical injection control is executed by the chemical injection control method for a coagulation-sedimentation processing device according to the present invention, in which raw water (for example, tap water, sewage, factory wastewater, etc.) is supplied to the coagulation tank 11. The flow rate of raw water supplied by the raw water supply pipe 12A (hereinafter referred to as "raw water flow rate" a raw water flowmeter 13 for measuring the turbidity of raw water (hereinafter also referred to as "raw water turbidity") and a raw water turbidity meter installed for the raw water supply pipe 12A for measuring the turbidity of the raw water (hereinafter also referred to as "raw water turbidity"). 14
, an inorganic flocculant injection device 15 for injecting an inorganic flocculant into the flocculant tank 11 to generate aggregates, that is, flocs; A mixing tank 16 for stirring and mixing the suspended water (hereinafter referred to as "flocculating tank effluent water") supplied from the flocculating tank 11 via the guide pipe 12B with the organic polymer flocculant.
and an organic polymer flocculant injection device 17 for injecting the organic polymer flocculant into the mixing tank 16 to increase the particle size of the aggregates and improve their sedimentation speed.
The suspended water (hereinafter referred to as "mixing tank outflow") is disposed on the downstream side of the mixing tank 16 and is stirred and mixed with the inorganic flocculant and the organic polymer flocculant and supplied from the mixing tank 16 via the guide pipe 12C. A settling tank 18 is used to settle the flocculates by allowing the flocs to settle in the settling tank 18, and clear mixing tank effluent (hereinafter referred to as "treated water") is used to settle the flocculates in the settling tank 18. Treated water turbidity meter 1 for measuring the turbidity of water (hereinafter also referred to as "treated water turbidity")
9. The settling tank 18 is provided with a discharge pipe 12D for discharging treated water and a discharge pipe 12E for removing aggregates settled at the bottom. The coagulation sedimentation treatment device 10 also includes a raw water flow meter 1
The first to third input terminals are respectively connected to the output terminal of the raw water flow meter 13, the output terminal of the raw water turbidity meter 14, and the output terminal of the treated water turbidity meter 19.
The measured raw water flow rate measured by the raw water turbidity meter 14, the raw water turbidity measured by the raw water turbidity meter 14, and the treated water turbidity meter 1
An amplifier circuit 20 for suitably amplifying and outputting the measured values of the treated water turbidity measured in No. 9, and an input terminal connected to the first output terminal of the amplifier circuit 20, Divide the currently measured raw water turbidity value by its design value to obtain the raw water turbidity design value ratio N.
An arithmetic circuit 21A for calculating and an amplifier circuit 2
The input terminal is connected to the first output terminal of 0, and the current measurement value of raw water turbidity given from the amplifier circuit 20 is compared with the previous measurement value of raw water turbidity given earlier from the amplifier circuit 20. and another arithmetic circuit 21B for calculating the rate of change S of raw water turbidity. The coagulation sedimentation processing device 10 further includes an arithmetic circuit 21
The first and second input terminals are connected to the output terminals of A and 21B, respectively, and the third input terminal is connected to the setting circuit 2.
The setting circuit 22 is connected to the first output terminal of the setting circuit 22.
Calculation of the design value ratio N of raw water turbidity calculated in the arithmetic circuit 21A from the measured value of raw water turbidity based on fuzzy rules stored in advance (for example, fuzzy rules f ₁₁ , ~, f ₁₉ in Table 1). a fuzzy inference circuit 23 for calculating the change rate P of the inorganic flocculant injection rate from the calculated value of the change rate S of the raw water turbidity calculated by the arithmetic circuit 21B from the measured value of the raw water turbidity, Reasoning circuit 2
The first and second input terminals are respectively connected to the output terminal of No. 3 and the second output terminal of the amplifier circuit 20, and the third input terminal is connected to the second output terminal of the setting circuit 22. Inferred value and processing of the change rate P of the inorganic flocculant injection rate by the fuzzy inference circuit 23 based on other fuzzy rules stored in advance in the circuit 22 (for example, fuzzy rules f ₂₁ , ~, f ₂₉ in Table 2) It also includes another fuzzy inference circuit 24 for determining the change rate R of the organic polymer flocculant injection rate from the measured value of water turbidity Q by fuzzy inference. In addition, the coagulation-sedimentation processing device 10 includes output terminals of the fuzzy inference circuits 23 and 24, a third output terminal of the amplifier circuit 20, and a first terminal of the inorganic flocculant injection device 15.
Second input end and organic polymer flocculant injection device 1
The inferred value of the change rate P of the inorganic flocculant injection rate and the organic polymer flocculant injection rate determined by the fuzzy inference circuits 23 and 24, which are arranged between the first and second input terminals of The estimated value of the change rate P is given to the inorganic flocculant injection device 15 and the organic polymer flocculant injection device 17, respectively, and the measured value of the raw water flow rate is sent from the amplifier circuit 20 to the inorganic flocculant injection device 15 and the organic polymer flocculant injection device 17. A sequencer 25 is provided for supplying the medicine to both of the medicine injection devices 17. Incidentally, the arithmetic circuits 21A, 21B, the setting circuit 22, and the fuzzy inference circuits 23, 24 are usually configured by computers. Also, setting circuit 2
2 may be incorporated into the fuzzy inference circuits 23 and 24. The inorganic coagulant injection device 15 changes the current value of the inorganic coagulant injection rate according to the inferred value of the change rate P of the inorganic coagulant injection rate given via the sequencer 25, and changes the current value of the inorganic coagulant injection rate. The injection amount of the inorganic flocculant is changed according to the changed value and the measured value of the raw water flow rate given via the sequencer 25, and the inorganic flocculant is injected into the flocculation tank 11 according to the changed injection amount. . The organic polymer flocculant injection device 17 changes the current value of the organic polymer flocculant injection rate according to the inferred value of the change rate R of the organic polymer flocculant injection rate given via the sequencer 25, and The injection amount of the organic polymer flocculant is changed according to the changed value of the organic polymer flocculant injection rate and the measured value of the raw water flow rate given via the sequencer 25, and the organic polymer flocculant is injected according to the changed injection amount. A molecular flocculant is injected into the mixing tank 16. Furthermore, with reference to FIGS. 1 to 5 a ₁ to e, an explanation will be given of an embodiment of the chemical injection control method for a coagulation-sedimentation processing apparatus according to the present invention, and the operation of the coagulation-sedimentation processing apparatus that carries out the method. This will be explained in detail. (General operation of the coagulation and sedimentation treatment device 10 ) In the coagulation and sedimentation treatment device 10 , in the flocculation tank 11, raw water is supplied from a raw water supply source (not shown) as shown by arrow A through the raw water supply pipe 12A. By injecting an appropriate amount of inorganic flocculant from the inorganic flocculant injection device 15 and stirring and mixing,
The suspended solids in the raw water are flocculated to form aggregates (ie, flocs). Suspended water supplied as raw water and in which aggregates (i.e., flocs) have been formed in the flocculation tank 11 is led to the mixing tank 16 as flocculation tank effluent via the guide pipe 12B, and then to the organic polymer flocculant injection device 17. The particle size of the aggregates (ie, flocs) is increased by mixing with an appropriate amount of organic polymer flocculant injected from the flocculent. The coagulation tank effluent mixed in the mixing tank 16 is supplied to the settling tank 18 via the guide pipe 12C as the mixing tank effluent. In the settling tank 18, the water flowing out of the mixing tank is allowed to stand still, so that aggregates (ie, flocs) are settled and removed. The aggregates (ie, flocs) settled in the settling tank 18 are removed as sludge through a discharge pipe 12E that opens at the bottom of the settling tank 18.
Further, the mixing tank effluent from which aggregates (i.e., flocs) have been removed in the settling tank 18 is discharged as treated water as shown by arrow B through the discharge pipe 12D, and is supplied to a subsequent treatment device (not shown). Alternatively, it can be released or reused as is. (Chemical injection control of coagulation sedimentation treatment device 10 ) A raw water flow meter 13 and a raw water turbidity meter 14 are arranged in the raw water supply pipe 12A, and the flow rate of raw water given to the flocculation tank 11 from the raw water supply source is controlled. (that is, the flow rate of raw water) is appropriately measured, and the turbidity of the raw water (that is, the raw water turbidity) is also appropriately measured (for example, at predetermined time intervals) and provided to the amplifier circuit 20. In addition, a treated water turbidity meter 19 is installed in the settling tank 18, and the turbidity of the mixing tank effluent from which aggregates (i.e., flocs) have been precipitated, i.e., the treated water, is measured as appropriate. (for example, at predetermined time intervals) and is applied to the amplifier circuit 20. The amplification circuit 20 appropriately amplifies the raw water turbidity measurement value given from the raw water turbidity meter 14 and outputs it to the arithmetic circuit 2.
1A, 21B and from the treated water turbidity meter 19 is appropriately amplified and given to the fuzzy inference circuit 24, and the raw water flow rate given from the raw water flow meter 13 is The measured value is appropriately amplified and given to the sequencer 25. The calculation circuit 21A calculates the design value ratio N of the raw water turbidity from the designed value of the raw water turbidity and the current measured value of the raw water turbidity given from the amplifier circuit 20. That is, the arithmetic circuit 21A calculates the raw water turbidity design value ratio N by dividing the current measured raw water turbidity value by the raw water turbidity design value. N=Currently measured value/design value The raw water turbidity design value ratio N calculated by the arithmetic circuit 21A is given to the fuzzy inference circuit 23. The arithmetic circuit 21B calculates the rate of change S of raw water turbidity from the raw water turbidity measurement value given from the amplifier circuit 20. That is, the calculation circuit 21B calculates the rate of change S of the raw water turbidity by dividing the difference between the current measured value and the previous measured value of the raw water turbidity by the current measured value. Arithmetic circuit 2
Calculated using 1B: S = Current measurement value - Previous measurement value / Current measurement value The rate of change S in the raw water turbidity that was obtained is given to the fuzzy inference circuit 23. The fuzzy inference circuit 23 generates a fuzzy set regarding the design value ratio N of raw water turbidity (see fuzzy set A in Figure 2a) and a fuzzy set regarding the rate of change S of raw water turbidity (see fuzzy set B in Figure 2b). and a fuzzy set regarding the change rate P of the injection rate of the inorganic flocculant (that is, the inorganic flocculant injection rate) injected into the flocculation tank 11 by the inorganic flocculant injection device 15 (No. P = change in the inorganic flocculant injection rate) The fuzzy rules shown in Table 1 that hold true between the current value of amount/inorganic coagulant injection rate (see fuzzy set C in Figure 2 c) f ₁₁ , ~, f ₁₀
Based on the calculated value of the design value ratio N of raw water turbidity calculated from the measured value of raw water turbidity and the calculated value of the rate of change S of raw water turbidity calculated from the measured value of raw water turbidity, the inorganic The change rate P of the flocculant injection rate is determined. On the other hand, the fuzzy inference circuit 24 generates a fuzzy set regarding the change rate P of the inorganic flocculant injection rate (see fuzzy set D in FIG. 3a) and a fuzzy set regarding the turbidity Q of the treated water given from the amplifier circuit 20 ( (see fuzzy set E in FIG. 3b) and changing the injection rate of the organic polymer flocculant injected into the mixing tank 16 by the organic polymer flocculant injection device 17 (that is, the organic polymer flocculant injection rate) In Table 2, the formula for rate R is established between R = amount of change in organic polymer flocculant injection rate/current value of organic polymer flocculant injection rate (see Fuzzy set F in Figure 3c). Fuzzy rules as shown
Based on f ₂₁ , ~, f ₂₉ , from the inferred value of the change rate P of the inorganic flocculant injection rate obtained by the fuzzy inference circuit 23 and the measured value of the treated water turbidity Q, the inorganic Change rate R of polymer flocculant injection rate
seek. The inferred value of the change rate P of the inorganic flocculant injection rate and the inferred value of the change rate R of the organic polymer flocculant injection rate obtained by the fuzzy inference circuits 23 and 24 are calculated by the sequencer 25, respectively. It is applied to the flocculant injection device 15 and the organic polymer flocculant injection device 17. The inorganic flocculant injection device 15 and the organic polymer flocculant injection device 17 are also provided with a measured value of the raw water flow rate from an amplifier circuit 20 via a sequencer 25 . As a result, in the inorganic flocculant injection device 15 and the organic polymer flocculant injection device 17, the inference results obtained by the fuzzy inference circuits 23 and 24, that is, the inference value of the change rate P of the inorganic flocculant injection rate and the organic The current value of the inorganic flocculant injection rate and the current value of the organic polymer flocculant injection rate are changed according to the inferred value of the change rate R of the polymer flocculant injection rate. The injection amount of the inorganic flocculant supplied to the flocculation tank 11 and the mixing tank 16, respectively, according to the changed value of the polymer flocculant injection rate and the measured value of the raw water flow rate given via the amplifier circuit 20. The injection amount of the organic polymer flocculant is changed, and the inorganic flocculant and the organic polymer flocculant are respectively injected into the flocculating tank 11 and the mixing tank 16 according to the changed injection amount. (Fuzzy Inference of Coagulation and Sedimentation Treatment Apparatus 10 ) Since it would be very complicated to generalize and explain the fuzzy inference executed by the fuzzy inference circuits 23 and 24, here, we will explain that the raw water turbidity is 100
When the injection rate of inorganic flocculant (here aluminum sulfate) and organic polymer flocculant is
In the coagulation and sedimentation treatment equipment 10 designed to be 50 mg/l and 1.0 mg/l, the previous measured value of raw water turbidity was 100 degrees, and the injection rate of inorganic flocculant and organic polymer flocculant at that time are 50 each
An example case will be described in which the treated water turbidity Q is 8 degrees with mg/l and 1.0 mg/l, and the current measured value of raw water turbidity changes to 125 degrees. (Inference in the fuzzy inference circuit 23) The calculation circuit 21A calculates the design value ratio N=1.25 from the design value of raw water turbidity of 100 degrees and the current measured value of 125 degrees, and the calculation circuit 21B The rate of change S from the measured value of 100 degrees and the current measured value of 125 degrees
= +20% is calculated. The fuzzy inference circuit 23 includes arithmetic circuits 21A, 2
When receiving the raw water turbidity design value ratio N = 1.25 and the raw water turbidity change rate S = +20% from 1B, the fuzzy sets A, ~, C and fuzzy rules f ₁₁ , ~, f input from the setting circuit 22 are received. ₁₉ , the membership functions and fuzzy rules involved at this time are selected. In other words, the fuzzy inference circuit 23 calculates the design value ratio N of raw water turbidity in (i) fuzzy sets A, ~, C;
= 1.25 intersects member-hop functions H _A , M _A
, and the rate of change in raw water turbidity S = +20%, select the member shop functions H _B and M _B (Fig. 2 a to c
), and then (ii) in fuzzy rules f ₁₁ , ~, f ₉ , fuzzy rules f 11 , f ₁₂ that include one of membership functions H _A , M _A and one of other membership functions H _B , _{M B} , f ₁₄ and f ₁₅ (see Table 11). Regarding Fuazii rule f ₁₁ , as is clear from Figure 4 a ₁ and a ₂ , the raw water turbidity design value ratio N = 1.25
Since the function value _B1 corresponding to the rate of change in raw water turbidity S = +20% is larger than the function value _A1 corresponding to
The fuzzy inference circuit 23 calculates the membership function by setting the height of the membership function PB _C belonging to the fuzzy set C shown in FIG. 2c to _A1 .
Create PB _C ^*1 (see Figure 4 a ₃ ). Regarding the fuzzy rule f ₁₂ , as is clear from Figure 4 b ₁ and b ₂ , the raw water turbidity design value ratio N = 1.25
Since the function value _A2 corresponding to the rate of change in raw water turbidity S = +20% is larger than the function value _A2 corresponding to
The fuzzy inference circuit 23 creates the membership function PM C ^*2 by setting the height of the membership function _{PM C} belonging to the fuzzy set C shown in FIG. 2 c to _A2 (see FIG. 4 b ₃ ). Regarding the fuzzy rule f ₁₄ , as is clear from Figure 4 c ₁ and c ₂ , the rate of change in raw water turbidity S is lower than the function value _A4 corresponding to the design value ratio N = 1.25 of raw water turbidity.
Since the function value _B4 corresponding to =+20% is small, the fuzzy inference circuit 23 calculates the membership function by setting the height _B4 of the membership function PMC belonging to the fuzzy set _C shown in FIG.
Create PM _C ^*3 (see Figure 4 c ₃ ). Regarding the fuzzy rule f ₁₅ , as is clear from Figure 4 d ₁ and d ₂ , the raw water turbidity design value ratio N = 1.25
Since the function value _B5 for the change rate S = +20% of raw water turbidity is smaller than the function value _A5 corresponding to By setting the value to _B5 , the membership function
Create ZOc ^*4 (see Figure 4 d ₃ ). The fuzzy inference circuit 23 uses the membership functions PB _C ^*1 , PMc ^*2 , PM _C ^*3 and
Calculate the center of gravity M ₁ for the hatched area surrounded by the four elements of ZOc ^*4 (see Figure 4 e). vinegar

【table】

[Table] That is, the fuzzy inference circuit 23 calculates the abscissa of the center of gravity _M1 to be +21.54%, and infers this as the change rate P of the inorganic flocculant injection rate. Inferred value of change rate P of inorganic flocculant injection rate +21.54
% is from the fuzzy inference circuit 23 to the sequencer 25
The inorganic flocculant is supplied to the inorganic flocculant injection device 15 via the inorganic flocculant injection device 15. The inorganic coagulant injection device 15 calculates the inorganic coagulant injection rate from the inferred value of change rate P of the inorganic coagulant injection rate +21.54% and the current value of the inorganic coagulant injection rate of 50 mg/l.
After changing the inorganic flocculant injection rate to 60.8 mg/l, the injection amount of the inorganic flocculant is determined according to the changed value of the inorganic flocculant injection rate of 60.8 mg/l and the measured value of the raw water flow rate given from the amplifier circuit 20 via the sequencer 25. change. (Inference in the fuzzy inference circuit 24) The fuzzy inference circuit 24 is similar to the fuzzy inference circuit 2.
From 3, the inferred value of the change rate P of the inorganic flocculant injection rate +
21.54% and a measured value of 8 degrees of treated water turbidity Q from the amplifier circuit 20, the setting circuit 22
Membership functions and fuzzy rules involved at this time are selected from the fuzzy sets D, ~, F and fuzzy rules f ₂₁ , ~, f ₂₉ input from . In other words, the fuzzy inference circuit 24 calculates (i) in the fuzzy sets D, ~, F, the membership functions H _D , M _D that intersect with the change rate P = +21.54% of the inorganic flocculant injection rate, and the treated water turbidity Q Select the membership functions L _E and M _E that intersect =8 (see Figure 3 a to c), and then (ii) select the membership functions H _D and M _D in the fuzzy rules f ₂₁ , ~, f ₂₉ . Select fuzzy rules f ₂₂ , f ₂₃ , f ₂₅ and f ₆ that include any of the other membership functions L _E , M _E (see Table 2). Regarding the fuzzy rule f ₂₂ , as is clear from Figure 5 a ₁ and a ₂ , the change rate P of the inorganic flocculant injection rate
Since the function value _E2 corresponding to the treated water turbidity Q=8 is larger than the function value _D2 corresponding to =+21.54%,
The fuzzy inference circuit 24 creates the membership function PM F ^*1 by setting the height of the membership function _{PM F} belonging to the fuzzy set F shown in FIG. 3 c to _D2 (see FIG. 5 a ₃ ). Regarding the fuzzy rule f ₂₃ , as is clear from Figure 5 b ₁ and b ₂ , the change rate P of the inorganic flocculant injection rate
Since the function value _E3 corresponding to the treated water turbidity Q=8 is smaller than the function value _D3 corresponding to =+21.54%,
The fuzzy inference circuit 24 calculates the membership function by setting the height of the membership function ZO _F belonging to the fuzzy set F shown in FIG. 3c to be _E3 .
Create ZO _F ^*2 (see Figure 5 b ₃ ). Regarding the fuzzy rule f ₂₅ , as is clear from Fig. 5 c ₁ and c ₂ , the change rate of the inorganic flocculant injection rate P =
Since the function value _E5 corresponding to the treated water turbidity Q=8 is larger than the function value _D5 corresponding to +21.54%,
The fuzzy inference circuit 24 calculates the membership function by _setting the height of the membership function ZO _F belonging to the fuzzy set F shown in FIG.
Create ZO _F ^*3 (see Figure 5 c ₃ ). Regarding the fuzzy rule f ₂₆ , as is clear from Fig. 5 d ₁ and d ₂ , the change rate P of the inorganic flocculant injection rate
Since the function value _E6 corresponding to the treated water turbidity Q=8 is smaller than the function value _D6 corresponding to =+21.54%,
The fuzzy inference circuit 24 calculates the membership function by setting the height of the membership function ZO _F belonging to the fuzzy set F shown in FIG. 3c to be _E6 .
Create ZO _F ^*4 (see Figure 5 d ₃ ). The fuzzy inference circuit 24 uses the membership functions PM _F ^*1 , ZO _F ^*2 , ZO _F ^*3 and ZO _F created above.
^* Calculate the center of gravity M ₂ for the hatched area surrounded by the four elements. In other words, fuzzy inference circuit 2
4, the abscissa of the center of gravity M ₂ is calculated as +9.35%, and this is inferred as the change rate R of the organic polymer flocculant injection rate. Inferred value of change rate R of organic polymer flocculant injection rate +
9.35% is given from the fuzzy inference circuit 24 to the organic polymer injection device 17 via the sequencer 25. The organic polymer injection device 17 has an estimated value of +9.35% for the change rate R of the organic polymer flocculant injection rate, and the organic polymer flocculant injection rate R is +9.35%.

[Table] After changing the organic polymer flocculant injection rate from the current value of 1.0 mg/l to 1.09 mg/l, the changed value of the organic polymer flocculant injection rate is 1.09 mg/l. The injection amount of the organic polymer flocculant is changed according to the measured value of the raw water flow rate given from the amplifier circuit 20 via the sequencer 25. In the above, fuzzy sets A and B are respectively the design value ratio N of raw water turbidity and its rate of change S.
and fuzzy set C(=D),
Although F is created for the change rate P of the inorganic flocculant injection rate and the change rate R of the organic polymer flocculant injection rate, the present invention is not limited to this, and if desired, For example, fuzzy sets A and B are created for raw water turbidity and its change amount, respectively, and fuzzy sets C (=D) and F
may be created for the amount of change in the inorganic flocculant injection rate and the amount of change in the organic polymer flocculant injection rate, respectively. In other words, according to the present invention, a fuzzy set A is created for the raw water turbidity or its design value ratio N, and a fuzzy set B is created based on the amount of change in the raw water turbidity.
Create a fuzzy set C (= ^D ) for the change amount or change rate P of the inorganic flocculant injection rate, and create the fuzzy set F for the organic flocculant injection rate ^or the change rate P. It may also be created for the change amount or change rate R of the polymer flocculant injection rate. Incidentally, when creating the fuzzy set A for raw water turbidity, since the measured value of raw water turbidity can be used directly, the arithmetic circuit 21A is removed. In addition, the fuzzy set B is calculated as the amount of change in raw water turbidity.
When creating S ^* , it may be calculated by the arithmetic circuit 21B. In addition, although the shape of the membership functions of the fuzzy sets A, ~, and F is all triangular in the description, the present invention is not limited to this, and the present invention is not limited to this. Depending on, the fuzzy set A, ~, F
The shape of the membership function may be any desired shape such as a trapezoid, a quadratic curve, or a probability density distribution curve. Furthermore, there are three membership functions belonging to the fuzzy set (in the case of fuzzy sets A, B, D, and E).
and five membership functions (in the case of fuzzy sets C and F), the present invention is not limited to this, and an appropriate number of membership functions may be selected as desired. . Furthermore, fuzzy inference is max-minimum (MAX−
MIN) method, the present invention is not limited to this, but may be implemented by any desired inference method such as the direct product method, marginal product method, or radical product method. It also includes cases where In addition, fuzzy inference is max-minimum (MAX−
MIN) method, the present invention is limited to this. For example, it can be performed by cutting off the top of the membership function in the conclusion part according to the function value of the membership function in the condition part obtained by the maximum-minimum (MAX-MIN) method. It also includes cases where (3) Effects of the Invention As is clear from the above, the chemical injection control method of the coagulation-sedimentation treatment apparatus according to the present invention has the following steps: In a chemical injection control method for a coagulation-sedimentation treatment apparatus in which an inorganic flocculant and an organic polymer flocculant are injected into raw water, (a) a first step of measuring the raw water flow rate with a raw water flow meter;
and (b) a second step of measuring raw water turbidity using a raw water turbidity meter.
(c) A third step of measuring the turbidity of the treated water using a treatment turbidity meter; (d) Calculating the raw water turbidity from the measured value of the raw water turbidity measured in the second step. a fourth step of calculating the amount of change or rate of change, and (e) fuzzy set regarding raw water turbidity, fuzzy set regarding amount of change or rate of change in raw water turbidity, and fuzzy set regarding amount of change or rate of change in inorganic flocculant injection rate; Based on the first fuzzy rule established between the set, the amount of change or rate of change in the raw water turbidity measured in the second step and the raw water turbidity calculated in the fourth step. a fifth step of determining the amount or rate of change in the inorganic flocculant injection rate from the calculated value by fuzzy reasoning; (f) fuzzy set and turbidity of the treated water regarding the amount or rate of change in the inorganic flocculant injection rate; The amount of change in the inorganic flocculant injection rate determined in the fifth step based on the second fuzzy rule established between the fuzzy set regarding the degree of change and the fuzzy set regarding the change amount or change rate of the organic polymer flocculant injection rate Alternatively, a sixth step of determining the change amount or change rate of the organic polymer flocculant injection rate by fuzzy reasoning from the inferred value of the change rate and the measured value of the treated water turbidity measured in the third step. and (g) inorganic flocculant in accordance with the amount of change in the inorganic flocculant injection rate or the inferred value of the change rate determined in the fifth step and the measured value of the raw water flow rate measured in the first step. a seventh step of changing the injection amount of the inorganic flocculant and injecting the inorganic flocculant into the raw water; (h) the amount of change in the injection rate of the organic polymer flocculant obtained in the sixth step or the inferred value of the change rate; and the first
and an eighth step of injecting the organic polymer flocculant into the raw water by changing the injection amount of the organic polymer flocculant according to the measured value of the raw water flow rate measured in the step of (i) It has the effect of automating the injection of inorganic flocculants and organic polymer flocculants into raw water, and (ii) Injecting inorganic flocculants and organic polymer flocculants into raw water can be automated, and (ii) Injecting inorganic flocculants and organic polymer flocculants into raw water can be automated in real time. It has the effect of being able to change the injection amount of the inorganic flocculant and the organic polymer flocculant, and as a result, (iii) it has the effect of reducing the injection amount of the inorganic flocculant and the organic polymer flocculant, and ( iv) It has the effect of increasing the precision of coagulation and sedimentation treatment of raw water. In addition, in another chemical injection control method of the coagulation sedimentation treatment apparatus according to the present invention, an inorganic flocculant and an organic high In a chemical injection control method for a coagulation sedimentation treatment device in which a molecular flocculant is injected, (a) a first step of measuring the raw water flow rate with a raw water flow meter;
and (b) a second step of measuring raw water turbidity using a raw water turbidity meter.
(c) A third step of measuring the turbidity of the treated water using a treated water turbidity meter; (d) The measured value of the raw water turbidity measured in the second step is determined as the raw water turbidity. (e) calculating the amount of change or change in raw water turbidity from the measured value of raw water turbidity measured in the second step; (f) a fuzzy set regarding the design value ratio of raw water turbidity, a fuzzy set regarding the change amount or rate of change in raw water turbidity, and a fuzzy set regarding the change amount or change rate of the inorganic flocculant injection rate; Based on the first fuzzy rule established between the set, the calculated value of the design value ratio of the raw water turbidity calculated in the fourth step and the amount of change in the raw water turbidity calculated in the fifth step or a sixth step of calculating the change amount or change rate of the inorganic flocculant injection rate by fuzzy inference from the calculated value of the change rate; and (g) fuzzy set regarding the change amount or change rate of the inorganic flocculant injection rate. Inorganic flocculant injection determined in the sixth step based on the second fuzzy rule established between the fuzzy set regarding the treated water turbidity and the fuzzy set regarding the change amount or change rate of the organic polymer flocculant injection rate. From the inferred value of the rate change or rate of change and the measured value of the turbidity of the treated water measured in the third step, use fuzzy reasoning to determine the rate of change or rate of change in the organic polymer flocculant injection rate. (h) according to the amount of change in the inorganic flocculant injection rate or the inferred value of the change rate obtained in the sixth step and the measured value of the raw water flow rate measured in the first step; an eighth step of changing the injection amount of the inorganic coagulant and injecting the inorganic coagulant into the raw water; The inferred value of the rate and the first
and a ninth step of injecting the organic polymer flocculant into the raw water by changing the injection amount of the organic polymer flocculant according to the measured value of the raw water flow rate measured in the step of Therefore, it similarly has the effects (i) to (iv) described above.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing a coagulation-sedimentation processing apparatus in which chemical injection control is executed by an embodiment of the chemical injection control method for a coagulation-sedimentation processing apparatus according to the present invention, and FIGS. The first operation explanatory diagram for explaining one embodiment of the chemical injection control method for the coagulation sedimentation processing apparatus according to the present invention, and FIGS. A second operation explanatory diagram for explaining an example, FIGS. 4A to _4E are third operation explanatory diagrams for explaining an embodiment of the chemical injection control method for a coagulation sedimentation treatment apparatus according to the present invention, Figure 5 a ₁
-e are fourth operation explanatory diagrams for explaining one embodiment of the chemical injection control method of the coagulation-sedimentation processing apparatus according to the present invention. 10 ... Coagulation sedimentation treatment device, 11... Coagulation tank,
12A... Raw water supply pipe, 12B, 12C... Guide pipe, 12D, 12E... Discharge pipe, 13... Raw water flow meter, 14... Raw water turbidity meter, 15... Inorganic flocculant injection device, 16... Mixing tank, 17... Organic polymer flocculant injection device, 18... Sedimentation tank, 19... Treated water turbidity meter, 20... Amplification circuit, 21... Arithmetic circuit, 22... Setting circuit, 23, 24 ...Fuzzy inference circuit, 25...Sequencer.

Claims (1)

[Scope of Claims] 1. A coagulation-sedimentation treatment in which an inorganic flocculant and an organic polymer flocculant are injected into raw water in order to flocculate suspended solids in the raw water, remove the precipitate, and then discharge it as treated water. In the chemical injection control method for the device, (a) a first step that measures the raw water flow rate using a raw water flow meter;
and (b) a second step of measuring raw water turbidity using a raw water turbidity meter.
(c) a third step of measuring the turbidity of the treated water with a treated water turbidity meter; (d) determining the raw water turbidity from the measured value of the raw water turbidity measured in the second step. (e) a fuzzy set related to raw water turbidity, a fuzzy set related to the amount or rate of change in raw water turbidity, and a change amount or rate of change in the inorganic flocculant injection rate; Based on the first fuzzy rule established between the fuzzy set, the amount of change or rate of change between the measured value of raw water turbidity measured in the second step and the raw water turbidity calculated in the fourth step a fifth step of calculating the change amount or change rate of the inorganic coagulant injection rate by fuzzy reasoning from the calculated value; (f) Fuzzy set and treated water regarding the change amount or change rate of the inorganic coagulant injection rate; Changing the inorganic flocculant injection rate determined in the fifth step based on the second fuzzy rule established between the fuzzy set regarding turbidity and the fuzzy set regarding the change amount or change rate of the organic polymer flocculant injection rate A sixth step of calculating the change amount or change rate of the organic polymer flocculant injection rate by fuzzy reasoning from the inferred value of the amount or change rate and the measured value of the treated water turbidity measured in the third step. (g) inorganic flocculation according to the amount of change in the inorganic flocculant injection rate or the inferred value of the change rate determined in the fifth step and the measured value of the raw water flow rate measured in the first step; a seventh step of changing the injection amount of the agent and injecting the inorganic flocculant into the raw water; (h) inference of the change amount or change rate of the organic polymer flocculant injection rate determined in the sixth step; value and first
and an eighth step of injecting the organic polymer flocculant into the raw water by changing the injection amount of the organic polymer flocculant according to the measured value of the raw water flow rate measured in the step of Characteristic chemical injection control method for coagulation sedimentation processing equipment. 2. In a chemical injection control method for a coagulation-sedimentation treatment device in which an inorganic flocculant and an organic polymer flocculant are injected into raw water in order to flocculate suspended solids in raw water, remove precipitates, and then discharge as treated water. , (a) The first step is to measure the raw water flow rate using a raw water flow meter.
and (b) a second step of measuring raw water turbidity using a raw water turbidity meter.
(c) A third step of measuring the turbidity of the treated water using a treated water turbidity meter; (d) The measured value of the raw water turbidity measured in the second step is determined as the raw water turbidity. (e) calculating the amount of change or change in raw water turbidity from the measured value of raw water turbidity measured in the second step; (f) a fuzzy set regarding the design value ratio of raw water turbidity, a fuzzy set regarding the change amount or rate of change in raw water turbidity, and a fuzzy set regarding the change amount or change rate of the inorganic flocculant injection rate; Based on the first fuzzy rule established between the set, the calculated value of the design value ratio of the raw water turbidity calculated in the fourth step and the amount of change in the raw water turbidity calculated in the fifth step or a sixth step of calculating the change amount or change rate of the inorganic flocculant injection rate by fuzzy inference from the calculated value of the change rate; and (g) fuzzy set regarding the change amount or change rate of the inorganic flocculant injection rate. Inorganic flocculant injection determined in the sixth step based on the second fuzzy rule established between the fuzzy set regarding the treated water turbidity and the fuzzy set regarding the change amount or change rate of the organic polymer flocculant injection rate. From the inferred value of the rate change or rate of change and the measured value of the turbidity of the treated water measured in the third step, use fuzzy reasoning to determine the rate of change or rate of change in the organic polymer flocculant injection rate. (h) according to the amount of change in the inorganic flocculant injection rate or the inferred value of the change rate obtained in the sixth step and the measured value of the raw water flow rate measured in the first step; an eighth step of changing the injection amount of the inorganic coagulant and injecting the inorganic coagulant into the raw water; The inferred value of the rate and the first
and a ninth step of injecting the organic polymer flocculant into the raw water by changing the injection amount of the organic polymer flocculant according to the measured value of the raw water flow rate measured in the step of Characteristic chemical injection control method for coagulation sedimentation processing equipment.