JPH0739000B2 - Sludge control device for sedimentation pond - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a control device for discharging sludge from a sedimentation basin.

B. Summary of the Invention The present invention is a sludge control device that discharges sludge from a high-speed coagulation sedimentation basin or a cross-flow type sedimentation basin at a predetermined cycle by a timer, and stores data of the actual sludge operation of an operator in a controller or the like. By determining the set values for the sludge cycle and sludge time based on the detected values such as the turbidity of raw water and the above data, the sludge control is automated and the equipment cost is suppressed. .

C. Problems to be solved by the conventional technology and the invention At present, in the sludge operation in the chemical sedimentation basin of a water purification plant, a sludge cycle and a sludge time are set by using a timer, for example, 10 minutes and 1 minute, respectively. Then, it is performed in a form similar to continuous sludge as much as possible. In this mud discharging method, the mud discharging cycle and the mud discharging time set in the timer must be manually changed at any time according to changes in raw water quality, especially turbidity, depending on the strength and experience of the operator. Therefore, when high turbidity occurs during the flood season, snowmelt season, etc., it is necessary to change the setting frequently and in a timely manner so as to shorten the sludge discharge cycle and lengthen the sludge discharge time. . In addition, the raw water turbidity becomes low during the dry season in the middle of winter, and the sludge discharge cycle and the sludge time are set to prevent sludge in the sedimentation basin from spoiling. It is necessary to change the settings even at midnight, and if this is not done, the quality of treated water in the sedimentation pond will deteriorate. In this way, the mud discharge operation itself is automated because it automatically opens and closes the mud discharge valve and turns the mud pump on and off automatically. How much should the mud cycle and the mud time be set? The setting action is artificially determined according to the enormous power and experience of the operator. However, such a method of artificially setting has a problem that an operator's burden is heavy.

In addition, as a method for completely automating sludge drainage control, the amount of sludge generated based on the turbidity of raw water is estimated, and the sludge accumulated in the sedimentation pond is determined based on the detection values of the sludge interface meter and sludge concentration meter. Therefore, it is also considered to estimate the amount of sludge by a computer such as a mini computer. However, this method is used in addition to a sludge concentration meter (for example, 5% full scale), a water quality measuring instrument such as a sludge interfacial meter and a raw water turbidimeter, and many measuring and controlling instruments such as a raw water flowmeter and a sludge flowmeter. A computer of the mini computer class is required, the equipment cost rises, and the estimation accuracy of the sludge retention state is low due to many disturbances.

An object of the present invention is to automate sludge control in a sedimentation basin and reduce capital investment.

D. Means for Solving Problems In the present invention, for example, when a slurry circulation type high-speed coagulation sedimentation basin is targeted, the detected values of sludge concentration and raw water turbidity of the secondary stirring chamber are input to a fuzzy controller or the like, Fuzzy calculation and PID calculation are performed and each set value of the sludge cycle and the sludge time is output as an output signal. The control method performed inside the fuzzy controller or the like takes a form that mimics the control method of an experienced operator. For example, a sludge concentration meter with a measurement range of 0 to 5000 mg / l is set in the secondary stirring chamber of the actual high-speed coagulation sedimentation basin, and the sludge discharge operation is performed for one year based on the manual setting of the timer by the operator. The results obtained are shown in FIG.
As can be seen from this figure, as the raw water turbidity increases, 2
The sludge concentration in the secondary stirring chamber also increases, and the operator shortens the sludge discharge cycle and lengthens the drainage time as the raw water turbidity increases to keep the increase in the sludge concentration constant. The present invention incorporates this principle into a controller or the like to automate the sludge control. Specifically, a feedforward control unit for determining each set value of the sludge cycle and the sludge time, and a correction for each of the set values. A feedback control unit for obtaining a value,
A timer setting unit that sets a timer based on the set value and the correction value.

E. Action In the feedforward control section, it was obtained from the data based on the actual sludge operation performed by manually setting the timer.
The relationship between each of the raw water turbidity and the sludge concentration in the stirring chamber and the sludge cycle, and the relationship between the raw water turbidity and each of the sludge concentration and the sludge time are stored in advance, and the relationship, the raw water turbidity and the Based on the detected values of sludge concentration, the set values of the sludge cycle and sludge time are calculated. Further, the feedforward control unit stores in advance the relationship between the raw water turbidity obtained based on the data during the sludge operation and the target value of the sludge concentration, and the relationship and the detected value of the raw water turbidity. The target value of the sludge concentration is obtained from the above, and the correction value is obtained for each set value of the sludge cycle and the sludge time so that the detected value of the sludge concentration becomes the target value. Then, a timer is set with the added value of the set value and the correction value of the sludge discharging cycle as the sludge discharging cycle and the added value of the set value of the sludge discharging time and the correction value as the sludge discharging time.

F. Embodiment FIG. 1 is a diagram showing an embodiment of the present invention. 1 is a high-speed aggregation sedimentation basin, the sedimentation tank 1 is introduced into the primary mixing chamber 1 ₂ of the lower side of the back of the frustoconical stirring chamber raw water via the inlet pipe 1 _1, stirring section 1 ₃ together is discharged through the discharge pipe 1 ₄ by coagulating sedimentation sludge by stirring, the raw water containing sludge its upper end so than Yue flow through the secondary agitation chamber 1 ₅ of the upper side, the solid-liquid at the solid-liquid separating section 1 ₆ It is to separate.

The inlet pipe 1 ₁ and the secondary agitation chamber 1 to ₅ respectively turbidimeter 2 and sludge concentration meter 3 is installed. 4 ₁ denotes a control unit feed-forward (hereinafter referred to as "FF"), as well as previously stored data obtained have not a preparative to waste sludge operation experienced operator, the turbidity meter 2 and this data It has a function of calculating the set value DS of the sludge cycle and the set value DT of the sludge time based on the detected values of the sludge concentration meter 3. The data is
Each relationship (second view of the sludge concentration and the waste sludge cycle of the obtained raw water turbidity and secondary mixing chamber 1 ₅ by performing a waste sludge operated by manual setting of the timer operator, for example, over one year ( a), (b)), and the turbidity of raw water and the sludge concentration have respective relations with the sludge discharge time (Figs. 3 (a), (b)), and were calculated from the stochastic set value of the operator. It is a thing.

4 ₂ is a feedback (hereinafter referred to as "FB") control unit, the detection value of the sludge concentration meter 3 after a predetermined time in consideration of the time lag used as FB control input signal, so that this value becomes a target value Correct the values of DS and DT. Regarding this target value, when the operator performs ideal sludge control, there is a macroscopically linear relationship between the raw water turbidity and the sludge concentration, as shown in FIG. And the detection value of the turbidimeter 2. In this case, sludge concentration = a x raw water turbidity + b
A linear expression (a and b are constants) may be used, or a stippled relationship as shown in FIG. 5 may be used. In this embodiment, the target value is calculated from the relationship shown in FIG. Looking for. The FB control unit 4 ₂ Specifically, outputs the correction value ΔDT correction value ΔDS and DT of DS corresponding to a deviation of the detected value and the target value of the sludge concentration.

4 ₃ is a timer setting unit, which calculates DS + ΔDS and DT + ΔDT, which are the added values of the output of the FF control unit 4 _{1 and} the output of the FB control unit 4 ₂ for each sludge cycle and sludge time, and calculates DS + ΔDS It has the function of setting a timer (not shown) as the cycle and DT + ΔDT as the sludge discharge time. Further, V is a sludge discharge valve, M is a motor, which constitute a sludge discharge means, and the timer controls the sludge discharge cycle and the sludge time. In this example at least, the FF control unit 4 _1, FB control unit 4 ₂ and a timer setting unit 4 ₃ digital controller (e.g. SLD
C) Incorporated in 4.

Next, the operation of the above embodiment will be described. Raw now been introduced into the sedimentation tank 1, where the solid-liquid separation by flocculation action of stirring section 1 ₃ is made treated water is to be discharged. In this case the detected values of the sludge concentration in the turbidity and secondary agitation chamber 1 ₅ of the raw water is input to the FF control unit 4 _1, the detection value TB and the second view of turbidity (a) and FIG. 3 (a) From the relationship shown in and from the sludge cycle DS ₁
And the sludge discharge time DT _1, and the detected value SS of sludge concentration
And the relationship shown in FIG. 2 (b) and FIG. 3 (b), the sludge cycle DS ₂ and the sludge time DT ₂ are obtained, and the set value DS is obtained from DS ₁ and DS _2, and DT Set value from ₁ and DT ₂
Find the DT. On the other hand the target value SS ₀ sludge concentration corresponding to TB from the relationship of FIG. 5 in FB control unit 4 ₂ is determined, correction values ΔDS and ΔDT corresponding to deviations between the SS is ₀ and the detected value SS Is output. Then, in the timer setting section 4 ₃ DS + ΔDS and DT +
ΔDT is calculated and the sludge cycle becomes DS + ΔDS,
Further, a timer (not shown) is set so that the sludge discharging time becomes DT + ΔDT, and the sludge discharging means is controlled according to the set value.

FIG. 6 is a diagram showing another embodiment of the present invention, in which a fangie controller is used in place of the digital controller. In the figure, 5 ₁ is a state measurement authorization unit for set amount, 5 ₂ is a set amount estimation rule storage unit, 5 ₃ is a state measurement authorization unit for correction amount 5 ₄ is a correction amount estimation rule storage unit, 5 ₅ is fuzzy inference , 5 ₆ is a set value determining unit, 5 ₇ is a correction value determining unit, and 5 ₈ is a timer setting unit, which are incorporated in the fuzzy controller 5.

In this embodiment, the state measurement for the correction amount with both the detection value of the detection value and the sludge concentration in secondary stirring chamber 1 ₅ of the raw water turbidity is input neither the state measurement certification unit 5 _1, 5 ₂ for the identification portion ₃ is further turbidity of treated water input set amount and measurement values of the correction amount is certified. The estimation rules of the estimation rule storage units 5 ₂ and 5 ₄ are applied to these values, respectively, and the results are input to the fuzzy inference unit 5 ₅ . Furthermore the calculation result of the fuzzy inference section 5 ₅ Te also DOO stamen, DerutaDS and ΔDT are determined by the correction value determination section 5 ₇ with DS and DT is determined by the setting value determination unit 5 _6, timer setting unit 5 Set a timer (not shown) so that the sludge cycle becomes DS + ΔDS and the sludge time becomes DT + ΔDT by ₈ . In the embodiment shown in FIG. 6 in the above, the fuzzy inference section 5 ₅ and setting value determination unit 5 ₆ corresponds to the FF control unit, Fiji inference unit 5 ₆ and the correction value determination section 5 ₇ FB
It corresponds to the control unit.

FIG. 7 is a diagram showing an embodiment of another invention. In this embodiment, the settling basin is a cross-flow type, and instead of the sludge concentration in the secondary stirring chamber, the drainage pit of the settling basin is used. This is different from the above-mentioned invention in that each detected value of the sludge interface of sludge concentration is used as an input signal of the FF control section and the FB control section. Figure 7 during 6 is a sedimentation tank of the horizontal flow type, the raw water that has flowed from the flocculation basin 6 ₁ Te this sedimentation basin 6 is a solid-liquid separation, discharge mud pits 5 in the sludge scraped up machine precipitated sludge fraction is not shown Can be scraped to ₂ . 7 is a turbidimeter, detects the raw water turbidity of flocculation basin 6 _1. 8 is a sludge concentration and interface meter-light having a function of detecting a sludge concentration and sludge interface level, it detects each value of the waste sludge pit 6 _2. 6 ₃ is an inclined plate sedimentation device. 9 digital controller 9 ₁ FF controller, 9 ₂ FB control unit 9 ₃ is a timer setting unit. FF controller 9 ₁
Then, the detected values of sludge concentration and interface sludge concentration 8 were corrected based on the detected values of the sludge interface, and based on the corrected sludge concentration and the detected value from turbidity meter 7, Fig. 1 DS and DT are determined using the relationship shown in FIG. 2 in the same manner as the embodiment shown in FIG. Since this time, the sludge concentration raw water turbidity of waste sludge pit 6 in ₂ are expected to have the relationship shown in FIG. 4 similar, using the relationship shown by the FB control unit 9 ₂ in FIG. 5 for example obtains a target value of the sludge concentration in accordance with the raw water turbidity, Ru sludge concentration of waste sludge pit 6 within ₂ to correction control to be maintained near a target value.
That is similar to the embodiment shown in FIG. 1 ΔDS from FB control unit 9 _2,
ΔDT is output. As the waste sludge cycle DS + ΔDS by the timer setting section 9 _3, and sets the timer DT + .DELTA.DT as waste sludge time.

Here, as the input signal from the sludge concentration / interface meter 8 in the FF controller 9 ₁ and the FB controller 9 ₂ , only the detected value of the sludge concentration or only the detected value of the sludge interface may be used.

Also in the conventional manual control, it had established the timer settings while watching the waste sludge concentration of sludge interface and Haidorokan 6 _4,
Since the waste sludge concentration varies between 0-5%, the detection value from the sludge concentration meter was inserted directly into Haidorokan 6 ₄ unreliable. In the present invention, therefore, the sludge concentration and interface meter on the waste sludge pit 6 ₂ 8
It is desirable from the viewpoint of improving reliability that the detection value is used by arranging.

Further, also in the sludge control of the lateral flow type sedimentation tank, a fuzzy controller as shown in FIG. 6 can be used instead of the digital controller. In this case, the secondary stirring chamber ₁₅
Instead of the sludge concentration, the detection values of both the sludge concentration and the sludge concentration from the interface totalizer 8 and the sludge interface are used, or one of them is used. If the fuzzy controller is used to perform fuzzy control using more ambiguous information in this manner, the accuracy of determining ΔDS and ΔDT is increased, and thus more detailed control can be performed.

H. Effect of the Invention According to the present invention, the sludge control is automated because the timer setting value is automatically obtained by automatically obtaining the timer set value corresponding to the sludge cycle and the sludge time, thereby reducing the burden on the operator. Is reduced. Then, based on the data of the actual sludge operation of the operator, DS and DT are determined by FF control, and correction control is performed by obtaining each correction value of DS and DT by FB control. Fine sludge control can be performed, and ideal sludge operation can be realized. In addition, since it can be controlled by a turbidity meter, a sludge concentration meter, a sludge interface meter, and a controller such as a digital controller, the initial investment is small and it is economical.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 (a),
(B) is a relationship diagram for determining the sludge cycle, FIG. 3 (a),
(B) is a relationship diagram for determining the sludge discharge time, FIG. 4 is a data diagram showing the relationship between the raw water turbidity and the sludge concentration, FIG. 5 is a graph for setting the sludge concentration target value, and FIG. 6 is the present invention. FIG. 7 is a block diagram showing another embodiment of the present invention, and FIG. 7 is a block diagram showing another embodiment of the present invention. 1 ... High-speed coagulation sedimentation basin, 2,7 ... Turbidity meter, 3 ... Sludge concentration meter, 4 ₁ , 5 ₁ FF control unit, 4 ₂ , 9 ₂ FB control unit, 4 ₃ ,
9 ₃ ...... Timer setting part, 5 ...... Fuzzy controller, 6
...... A cross-flow type sedimentation pond.

Claims (2)

[Claims] 1. A settling basin in which raw water containing sludge is introduced into a stirring chamber in the settling tank to cause solid-liquid separation by aggregating and sedimenting the sludge by stirring, and a sludge discharging cycle and a discharging time of the separated sludge are timer-controlled. In the sludge control device controlled by, the relationship between each of the raw water turbidity and sludge concentration in the agitation chamber and the sludge cycle obtained from the data based on the actual sludge operation performed by setting the timer manually. , And the relationship between the raw water turbidity and the sludge concentration and the sludge discharge time are stored in advance,
Based on these relations and the detected values of the raw water turbidity and the sludge concentration, a feedforward control unit for obtaining each set value of the sludge cycle and the sludge time, and based on the data during the sludge operation. The relationship between the obtained raw water turbidity and the target value of the sludge concentration is stored in advance, and the target value of the sludge concentration is obtained from this relationship and the detected value of the raw water turbidity, and the detected value of the sludge concentration is A feedback control unit for obtaining a correction value for each set value of the sludge cycle and the sludge time so that the target value is obtained, and a sum value of the set value and the correction value of the sludge cycle is set as the sludge cycle and A sludge discharge control device for a sedimentation basin, comprising: a timer setting unit that sets a timer with the added value of the set value of the sludge discharge time and the correction value as the sludge discharge time. 2. In a sedimentation basin in which raw water containing sludge is introduced into a stirring chamber in the sedimentation basin and the sludge is precipitated to perform solid-liquid separation, a sludge discharge cycle and a discharge time of the separated sludge are controlled by a timer. In the sludge controller, the raw water turbidity and the sludge concentration and / or the sludge interface level lower than the sludge interface, which were obtained from the data based on the actual sludge operation performed by manually setting the timer, The relationship between the sludge cycle and the relationship between the raw water turbidity and the sludge concentration and / or sludge interface level and the sludge time are stored in advance, and the relationship, the raw water turbidity, the sludge concentration and / or the sludge are stored. A feedforward control unit for obtaining each set value of the sludge discharge cycle and the sludge time based on the detected value of the interface level, and the raw water turbidity obtained based on the data during the sludge operation and the above Sludge concentration and / Alternatively, the relationship between the sludge interface level and the target value is stored in advance, and the sludge concentration and / or the target value of the sludge interface level are obtained from the relationship and the detected value of the raw water turbidity, and the sludge concentration and / or the sludge interface is obtained. A feedback control unit that obtains a correction value for each set value of the sludge cycle and the sludge time so that the detected value of the level becomes the target value, and the addition value of the set value and the correction value of the sludge cycle are discharged. A mud control device for a sedimentation pond, comprising: a timer setting unit that sets a timer as a mud cycle and a sum of the set value of the mud discharge time and a correction value as the mud discharge time.