JPH01135599A - Sludge discharge controller for sedimentation tank - Google Patents

Abstract

PURPOSE:To automate, by automatically obtaining a value to be fixed by means of a timer, said value corresponding to a sludge discharge, period and a sludge discharge time. CONSTITUTION:Original water is introduced into a sedimentation tank 1 and subjected to solid-liquid separation by means of the flocculating effect of a stirrer 13, and treated water is discharged. The measured values of both the turbidity of the original water and the sludge concentration in a second stirring room 15 are inputted in an FF controller 41. A sludge discharge period DS1 and a sludge discharge time DT1 are obtained from the measured values TB of the turbidity and each of the relationships between them. From measured values SS of the sludge concentration and each of the relationships between them, a sludge discharge period DS2 and a sludge discharge time DT2 are obtained, and further a value DS to be fixed is obtained from the DS1 and DS2. Further, a value DT to be fixed is obtained from the DT1 and DT2, and an FB controller 42 fixes a target value SS0 of the sludge concentration, said target value corresponding to the TB. Then, a sludge-discharging means is controlled by setting a timer such that the sludge discharge time may be DT+DELTADT.

Description

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

B3 Summary of the Invention The present invention is a sludge control device that discharges sludge from a high-speed coagulation sedimentation tank or a galvanic type sedimentation tank at a predetermined period using a timer, in which data of an operator's actual sludge removal operation is stored in a controller, etc. By determining the setting values for the sludge removal cycle and sludge time based on the detected values of raw water turbidity, etc. and the above data, □ Automate sludge removal control and reduce equipment costs. This is what I did.

C1 Problems to be Solved by the Prior Art and the Invention At present, the sludge removal operation in the chemical sedimentation tank of a water treatment plant uses a timer to set the sludge period and the sludge time to, for example, 10 minutes and 1 minute, respectively. This is done in a manner as close to continuous mud removal as possible. □With this sludge removal method, the sludge removal period and sludge removal time set on the timer must be manually changed as needed according to changes in raw water quality, especially turbidity, with the cooperation and experience of the operator. Therefore, when high turbidity occurs during the flood season or snowmelt season, it is necessary to frequently change the settings in a timely manner to shorten the sludge cycle and lengthen the sludge time.
Moreover, it must be done day and night. In addition, during the dry season in the middle of winter, the concentration of raw water turbidity is low, and in order to prevent the sludge accumulated in the sedimentation tank from rotting, the sludge operation is carried out by setting the sludge cycle and sludge time, and when there is a sudden flood such as a typhoon, the turbidity of the raw water becomes low. Setting changes must be made even in the middle of the night, and if this is not done, the quality of treated water in the sedimentation pond will deteriorate. In this way, the sludge removal operation itself is automated, as the sludge valve is automatically opened and closed, and the sludge pump is automatically turned on and off. The setting behavior is artificially determined according to the cooperation and experience of the operator. However, such a method of making artificial settings has a problem in that it places a heavy burden on the operator.

In addition, as a method to fully automate sedimentation tank drainage control, the amount of generated sludge is estimated based on raw water turbidity, and the sludge stagnant in the sedimentation tank is estimated based on the detected values of the sludge interface meter and sludge concentration meter. It is also being considered to determine the amount of sludge discharged by estimating it using a calculator such as a minicomputer. However, this method requires water quality measuring instruments such as effluent sludge concentration meters (e.g. 5% full scale), sludge interface meters and raw water turbidity meters, as well as many measurement and control instruments such as raw water flow meters and sludge flow meters. Mini-computer-class calculators are required, which increases equipment costs, and the accuracy of estimating the state of sludge retention is relatively low due to many disturbances.

An object of the present invention is to automate the control of sludge removal from a sedimentation tank and to reduce capital investment.

Means for solving the D0 problem In the present invention, for example, when targeting a slurry circulation type high-speed coagulation sedimentation tank, the detected values of the sludge concentration and raw water turbidity in the secondary stirring chamber are input to a fuzzy controller etc. It performs calculations and PID calculations and outputs each set value of the mud removal period and mud removal time as an output signal. The control method performed inside a fuzzy controller or the like imitates the control method used by an experienced operator. A sludge concentration meter with a measurement range of, for example, 0 to 5000 mg/4 was installed in the secondary stirring chamber of an actual high-speed coagulation sedimentation tank, and the sludge removal operation based on manual timer settings by the operator was carried out over a period of one year. The results of the implementation are shown in the fourth
As shown in the figure. As can be seen from this figure, as the raw water turbidity increases, the sludge concentration in the secondary stirring chamber also increases. The increase in concentration is kept constant. The present invention incorporates this principle into a controller etc. to automate sludge removal control, and specifically includes a feedforward control section that calculates each set value of the sludge removal period and sludge removal time,
It is comprised of a feedback control section that calculates correction values for each set value, and a timer setting section that sets a timer based on the set values and correction values.

In the 80-action feedforward control section, the timer was manually set.
The relationship between raw water turbidity and sludge concentration in the stirring chamber and the sludge cycle, and the relationship between each of raw water turbidity and early sludge concentration and sludge time are stored in advance, and these relationships, raw water turbidity, and the above-mentioned relationship are stored in advance. Based on each detected value of sludge concentration, each set value of the sludge drainage cycle and sludge drainage time is determined. In addition, the feedforward system m section stores in advance the relationship between the raw water turbidity obtained based on the data during the sludge removal operation and the target value of the sludge concentration, and also detects this relationship and the raw water turbidity. A target value of the sludge concentration is determined from the value, and a correction value is determined for each of the set values 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 so that the added value of the set value of the mud removal cycle and the correction value is the mud removal cycle, and the added value of the set value of the mud removal time and the correction value is the mud removal time.

F. Embodiment FIG. 1 is a diagram showing an embodiment of the present invention. ■ is a high-speed coagulation sedimentation tank, and this sedimentation tank 1 is a pipe for introducing raw water! , to the primary stirring chamber on the lower side of the truncated conical stirring chamber! ,
Introduced into the stirring means! , the sludge is coagulated and precipitated by stirring and discharged through the discharge pipe 14, and the raw water containing the sludge is overflowed from the upper end through the secondary stirring chamber 11 on the upper side, and the solid-liquid separation section! , solid-liquid separation is performed.

Said introduction W1. and the secondary stirring chamber 1 are each equipped with a turbidity meter 2.
and a sludge concentration meter 3 are installed. 41 is a feedforward (hereinafter referred to as rFFJ) control unit, which stores in advance data obtained based on sludge removal operations by an experienced operator, and also combines this data with the turbidity meter 2 and sludge concentration meter. The setting value D of the sludge removal cycle is based on each detected value of 3.
It has a function of calculating S and a set value DT of mud removal time.

The data is the relationship between the raw water turbidity, the sludge concentration in the secondary stirring chamber, and the sludge cycle, which are obtained by an operator performing sludge removal operations by manual setting of a timer over a period of one year, for example. (Fig. 2 (a), (b)), and the relationship between raw water turbidity, the sludge concentration, and sludge drainage time (Fig. 3 (a), (b))
)), which was determined from the operator's probabilistic settings.

4. is a feedback (hereinafter referred to as rFBJ) control section, which uses the detected value of the sludge concentration meter 3 after a certain period of time as the FB control input signal, taking into account the time delay, and controls the DS and DT so that this value becomes the target value. Correct the value of. Regarding this target value, since there is a macroscopic linear relationship between the raw water turbidity and the sludge concentration as shown in Figure 4 when the operator performs ideal sludge drainage control, this relationship and the detected value of the turbidity meter 2. In this case, a linear equation of sludge concentration = aX raw water turbidity + b (a and b are constants) may be used, or a step-like relationship as shown in Figure 5 may be used; In the example, the target value is determined from the relationship shown in FIG. Specifically, the FB control unit 4. is the correction value ΔD of DS according to the deviation between the detected value and target value of sludge concentration.
A correction value ΔDT of S and DT is output.

4 is a timer setting section, which outputs the output of the FF control section 4I and the FB control section 4.4 for each of the sludge removal period and the sludge removal time. It has a function of determining DS+ΔDS and DT+ΔDT, which are the sum of the outputs of , and setting a timer (not shown) with DS+ΔDS as the mud removal period and DT+ΔDT as the mud removal time. Further, V is a mud draining valve, and M is a motor, which constitute mud draining means, and the mud draining cycle and mud draining time are controlled by the timer. In this example, the FF@@ section 4□, the FB control F44. and timer setting section 4
．． is built into a digital controller (eg 5LDC) 4.

Next, the operation of the above embodiment will be described. Now the raw water is introduced into the settling tank I, where the stirring means! It is assumed that solid-liquid separation is performed by the coagulation effect of , and treated water is discharged.

At this time, the turbidity of the raw water and the secondary stirring chamber 1. Each detected value of sludge concentration is input to the FF control unit 4I, and the detected value of turbidity TB
From the relationship shown in FIGS. 2(a) and 3(a), the sludge draining period DS1 and sludge draining time DTl are determined, and the detected value SS of the sludge concentration and the relationship shown in FIGS. 2(b) and 3 are calculated. From the relationship shown in (b), the sludge removal period DS and the sludge removal time DT are obtained.

Further, DS, which is a set value, is found from DSI and DS, and DT, which is a set value, is found from DTI and DT. On the other hand, FB@ll1 part 4. From the relationship shown in Figure 5, T
Target value SS of sludge concentration corresponding to H.

is determined, and 〇S and ΔDT are output as correction values corresponding to the deviation between this SSo and the detected value SS. and timer setting section 4. DS+ΔDS and DT+ΔDT are calculated, and a timer (not shown) is set so that the sludge removal cycle becomes DS+ΔDS and the sludge removal time becomes DT+ΔDT, and the sludge removal means is controlled according to the set values. .

FIG. 6 is a diagram showing another embodiment of the present invention, in which a fungi controller is used in place of the digital controller. In the figure, 58 is a condition measurement certification section for the set amount; 5. 5s is a set amount estimation rule storage section, 5s is a correction amount state measurement certification section 54 is a correction amount estimation rule storage section, 56
5 is a fuzzy inference section; 5 is a setting value determining section; 57 is a correction value determining section; 5. is a timer setting section, which is built into the fuzzy controller 5.

In this example, the detected value of raw water turbidity and the secondary stirring chamber 1. Both of the detected values of the sludge concentration are determined by the condition measurement certification section 58.5.
! At the same time, the turbidity of the treated water is further input to the state measurement certification section 5s for the correction amount, and the measured values for the set amount and the correction amount are certified. Then, the estimation rules in the estimation rule storage sections 52 and 54 are applied to these values, respectively, and the results are sent to the fuzzy inference section 5. will be input into. Furthermore, the fuzzy inference section 5. Based on the calculation result of 5. DS and DT are determined in the correction value determining section 5, ΔDS and ΔDT are determined in the correction value determining section 5, and the timer setting section 5. A timer (not shown) is set so that the mud removal period becomes DS+ΔDS and the mud removal time becomes DT+ΔDT. In the embodiment shown in No. 61!1 above, the fuzzy inference 115 and the setting value determination unit 5. is FF
Corresponding to the control section, the fuzzy inference section 56 and the correction value determination section 5. corresponds to F BliJ Gobe.

FIG. 7 is a diagram showing an embodiment of another invention, and this embodiment has the points that the settling tank is of a galvanometric type, and that the sludge concentration in the secondary stirring chamber is changed to the sludge pit of the settling tank. This invention differs from the above-mentioned invention in that the detected values of the sludge concentration and the sludge interface are used as input signals for the FF control section and the FB@1 section. 7th
6 in the figure is a galvanic type sedimentation tank, and this sedimentation tank 6 has a floc formation tank 6. The inflowing raw water is separated into solid and liquid, and the precipitated sludge is collected in a sludge scraper (not shown) in the sludge pit 6.
! It is collected by. 7 is a turbidity meter, which detects the turbidity of raw water in the floc formation pond 61. Reference numeral 8 denotes an optical sludge concentration/interface meter having a function of detecting sludge concentration and sludge interface level, and detects each part in the sludge drainage pit 6. 6.
is an inclined plate sedimentation device. The digital controller 91 is an FF control section, and 9j is an FB control section 9. is a timer setting section. FF control section 9. Now, the value of the sludge concentration detected by the sludge concentration/interface meter 8 is corrected based on the value detected at the sludge interface, and based on the corrected sludge concentration and the value detected by the turbidity meter 7, the result is shown in Figure 1. DS and DT are determined using the relationship shown in FIG. 2 in the same manner as in the embodiment shown in FIG. At this time, it is predicted that the sludge concentration in the sludge pit 6 and the raw water turbidity have the same relationship as shown in FIG. 4, so the FB control unit 9f uses the relationship shown in FIG. A target value of sludge concentration according to turbidity is determined, and correction control is performed so that the sludge concentration in the sludge pit 6 is maintained near the target value. That is, like the embodiment shown in FIG. 1, the FB control section 9. ΔDS and ΔDT are outputted from the timer setting section 9. Accordingly, a timer is set with DS+ΔDS as the mud removal period and DT+ΔDT as the mud removal time.

Here, the FF control section 9I and the FB control section 9. As the input signal from the sludge concentration/interface meter 8, only the detected value of the sludge concentration or only the detected value of the sludge interface may be used.

In addition, in conventional manual control, the sludge interface and the sludge pipe 64
The timer setting value was determined while checking the sludge concentration of C, but since the sludge concentration changes between 0 and 5%, the sludge drainage pipe 64
Detected values from sludge concentration meters inserted directly into the water are unreliable. Therefore, in the present invention, it is desirable to arrange a sludge concentration/interface meter 8 above the sludge pit 6 and use the detected value from the viewpoint of improving reliability.

Furthermore, in the sludge removal control of a galvanometric sedimentation tank, a fuzzy controller as shown in FIG. 6 may be used instead of the digital controller.

In this case, a secondary stirring chamber! Instead of the sludge concentration of , either the detected values of both the sludge concentration and the sludge interface from the sludge concentration/interface meter 8 are used, or one of them is used. If we use the fuzzy controller in this way and perform fuzzy control using more ambiguous information, ΔDS
Since the accuracy of determining ΔDT and ΔDT is increased, more fine-grained control can be performed.

H1 Effects of the Invention According to the present invention, since the timer setting values corresponding to the sludge removal period and sludge time are automatically determined and the timer settings are performed, sludge removal control is automated, thereby reducing the burden on the operator. Reduced. Then, DS and DT are determined by FF control based on the data of the operator's actual sludge removal operation.
Since each correction value of DS and DT is determined by B control and correction control is performed, fine sludge removal control can be performed and an ideal sludge removal operation can be realized. Furthermore, since it can be controlled by a controller such as a turbidity meter, sludge concentration meter, sludge interface meter, and digital controller, the initial investment is small and it is economical.

[Brief explanation of the drawing]

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 removal cycle, Figures 3 (a) and (b)
) is a relationship diagram for determining the sludge drainage time, Figure 4 is a data diagram showing the relationship between raw water turbidity and sludge concentration, Figure 5 is a graph for setting the target value of sludge concentration, and Figure 6 is a diagram for determining the sludge concentration target value. FIG. 7 is a block diagram showing another embodiment of the invention. l...High-speed coagulation and sedimentation tank, 2,7...Turbidity meter, 3...
・Sludge concentration meter, 4. ．． 91...FF@Obe, 4-. 9!
...FB control section, 4s, 9s...timer setting section, 5
...Fuzzy controller, 6...Cross-flow sedimentation tank. Fig. 1 To the explanation of the series of laughs and rows of Homiaki 2-turbidity meter 3--itto χl meter 4-11 digital control O-ra 4+---FF leg control section 4, --FB system Mja 43--One timer! 5! i Egg Fig. 2 Feather ￥ χ Periodic function y F, Product (a) (b) Raw water turbidity M (9/r) ff1Z;1
! (m9/l) Figure 3: Determination of evacuation time - review time (α) (b) Onsui Norishige (m9/r)
Figure 4: UK cloudy skin, dirt, humidity, Liao U branch, Shuhei ('9/z) Figure 5: Definition of power desert skin giant prefecture value, 7hufu thick X turbidity ('9/z) '9/Z)

Claims (2)

[Claims] (1) Introducing raw water containing sludge into the stirring chamber in the settling tank,
Regarding the sedimentation tank that coagulates and settles sludge through stirring and performs solid-liquid separation, the sludge control device uses a timer to control the sludge period and sludge time of the separated sludge. The relationship between 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 the sludge concentration and the sludge time, obtained from data based on the sludge operation. In addition to memorizing in advance,
a feedforward control unit that calculates set values for the sludge cycle and sludge time based on these relationships and the detected values of raw water turbidity and the sludge concentration; 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 determined from this relationship and the detected value of the raw water turbidity, and the detected value of the sludge concentration is determined. a feedback control unit that calculates a correction value for each of the set values of the sludge cycle and the sludge time so that the set values of the sludge cycle and the sludge time become the target values; A sludge removal control device for a settling basin, comprising: a timer setting section that sets a timer using a set value of a sludge removal time and an added value of a correction value as a sludge removal time. (2) Introducing raw water containing sludge into the stirring chamber in the settling tank,
In a sedimentation tank that settles sludge and performs solid-liquid separation, an actual sludge operation performed by manually setting the timer in a sludge control device that uses a timer to control the sludge period and time of separated sludge. The relationship between raw water turbidity and sludge concentration below the sludge interface and/or sludge interface level and the sludge cycle, and the raw water turbidity and the sludge concentration and/or sludge obtained from data based on The relationships between each interface level and the sludge drainage time are stored in advance, and the sludge cycle and sludge time are determined based on these relationships, raw water turbidity, and the detected value of the sludge concentration and/or sludge interface level. A feedforward control unit that calculates each setting value, and stores in advance the relationship between the raw water turbidity obtained based on the data during the sludge removal operation and the target value of the sludge concentration and/or sludge interface level. , the target value of the sludge concentration and/or sludge interface level is determined from this relationship and the detected value of raw water turbidity, and the sludge drainage cycle is adjusted so that the detected value of the sludge concentration and/or sludge interface level becomes the target value. and a feedback control unit that calculates a correction value for each set value of the sludge removal time; A sludge removal control device for a sedimentation basin, comprising: a timer setting section that sets a timer using an added value as a sludge removal time.