JPS6255884B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic deposit discharge control system for depositing and discharging deposits.

The outline of the system is to calculate the amount of settled solids with respect to the sediment such as sludge deposited in the sedimentation tank, select a container for sediment that is full or reach a predetermined amount, and automatically remove the sediment that has accumulated in that container. This is an automatic discharge control system for the deposits that are removed at a specific time, and in the calculation formula for calculating the discharge interval of the deposits, for calculating the amount of deposits and the discharge interval for discharging the deposits. The discharge coefficient (calculation coefficient) is separated from the discharge coefficient (calculation coefficient), and the discharge coefficient is stored in a table in advance in correspondence with the average concentration of the water to be treated over a given period. The discharge coefficient is calculated backwards to correct the stored discharge coefficient.This allows for efficient discharge treatment of sludge, etc. that is suitable for actual operation.

An example of this type of automatic sediment discharge control system is an automatic sludge discharge control system.

A calculation method for the volume of settled sludge, sludge discharge interval, etc. based on the calculation method of the amount of settled solids in the conventional automatic sludge discharge control system is based on the patent application No. 53-143559 (Patent Application No. Opening 55-70310
This will be disclosed in the following issue.

Therefore, as a conventional technology, a sludge treatment plant to which an automatic sludge discharge control method is applied will be described. FIG. 1 shows its block diagram.

1 is a sludge treatment device, and 2 is its sludge discharge control device.

The sludge treatment device 1 includes a water landing well 3 and a water landing well 3.
A stirring pond 4 into which the water to be treated flows in, a floc formation pond 5 arranged on the downstream side of this stirring pond 4, a settling tank 6, a filtration pond 7 arranged on the downstream side of this settling tank 6, and further , a water purification tank 8 placed on the downstream side thereof, hoppers 61, 62, 63, 64 placed at the bottom of the settling tank 6, and a sludge basin 9 for storing the sludge discharged from these hoppers. .

On the other hand, the sludge discharge control device 2 includes a detector 10a that detects the turbidity of raw water placed in the landing well 3, a detector 10b that detects the flow rate of raw water flowing from the landing well 3 into the stirring pond 4, and It is equipped with a detector group consisting of a detector 10c arranged in front of the outflow trough 6a of the pond 6 for detecting the turbidity of the treated water, and an accumulated sludge amount calculator.

The accumulated sludge amount calculator is the raw water sludge amount calculator 11
, a deposited sludge amount calculator 12, and a sludge amount calculator 13 for flocculants such as PAC (polyaluminum chloride). Here, the raw water sludge amount calculator 11
are raw water flow rate Qn, raw water turbidity Tr, and treated water turbidity.
The sludge amount calculator 13 calculates the amount of sludge based on the turbidity removal in the raw water from Tt, and calculates the amount of undissolved material by the flocculant injected into the source water from the flocculant injection rate Pn, a constant, and the flow rate of the raw water. The amount of sludge is calculated, and the accumulated sludge amount calculator 12 calculates the amount of sludge solids Dn from the sludge concentration α based on these calculated values.

Now, the sludge discharge control device 2 calculates the amount of sludge solids using these various calculation units, and then discharges the sludge and then performs the next operation based on the relationship between the hopper volume, constants determined by the process, safety factors, sludge concentration, etc. The interval until the next discharge of sludge, the so-called period until the next discharge of sludge (hereinafter referred to as the sludge discharge interval)
The sludge is discharged from a predetermined hopper by performing processing such as calculating , and controlling the opening and closing of the discharge valve of the hopper.

By the way, the constants, safety factors, sludge concentration, etc. that are determined by the process, which are the basis of such calculations, are actually determined by experimental values such as jar tests, or actually measured values in specific situations. be.
However, in reality, changes in the quality of raw water cause differences in the flocculation effect, which increases or decreases, resulting in actual control based on calculated values in such automatic processing no longer matching reality.
In addition, for example, with respect to changes in sludge concentration due to high turbidity during or before and after a typhoon, there is a problem in that it is difficult to control using calculated values as appropriate test data cannot be obtained.

This invention was made in view of the problems of the prior art, and in addition to solving these problems, it also provides a method for actually controlling objects when accumulating and discharging deposits. It is an object of the present invention to provide an automatic deposit discharge control system that can obtain suitable data and perform automatic discharge processing of deposits in accordance with the data.

In order to achieve such an objective, the present invention separates the theoretical elements of calculating the amount of accumulated sludge from the elements that cause non-conformity values during water purification operation, and
The sludge drainage coefficient, which is an element that causes a nonconformity value, is stored in a table form, and this table is updated according to the actual state of the water to be treated to obtain calculation results that match reality.

Therefore, the present invention provides a container for depositing substances to be deposited contained in a liquid to be treated, a first container for detecting the concentration of the substances to be deposited in the liquid to be treated and a liquid after treatment;
a second detector and a detector that detects the amount of inflow of the liquid to be treated into the container; the substance to be deposited is deposited in the container by mixing a flocculant or the like with the liquid to be treated; In an automatic sediment discharge control method in which a full or predetermined amount of sediment is automatically removed from the container by calculating the amount of precipitated solids in the sediment, the average concentration of the liquid to be treated over a predetermined period of time is determined. The device is equipped with a storage section that stores a discharge coefficient of the deposited material corresponding to the amount of the deposited material, and a calculation section. Calculating an average amount of deposits in the container over a predetermined period by the calculating section, and calculating an interval for discharging the deposits from the container from the discharge coefficient read from the storage section and the average amount of deposits, According to this discharge interval, the deposited material is discharged from the container, and if the deposit is discharged at any time depending on the actual accumulation state of the deposit in the container, at that time. , calculating the discharge coefficient backward from the period from the previous discharge to the current discharge, the average concentration of the liquid to be treated, and the average deposition amount, and rewriting the corresponding discharge coefficient in the storage unit for this average concentration; This relates to an automatic discharge control method for such sludge, etc.

In this way, depending on the actual state of accumulation of deposits in the container, when discharging at any time, the discharge coefficient is calculated backward from the period until discharge, the average concentration of the liquid to be treated, and the average deposit amount. By rewriting the corresponding discharge coefficient in the storage unit for the average concentration, even if there is a difference in the coagulation effect due to changes in the quality of the liquid to be treated, this can be maintained. Accordingly, the calculated value can be calculated in accordance with the reality. Therefore, the actual control will not become out of compliance with reality. In particular, in automatic sludge discharge control, even if the flocculation effect varies due to changes in the quality of raw water, calculated values can be calculated in accordance with the actual situation. Therefore, the actual control will not become inconsistent with reality, and it will also be possible to use appropriate actual data for changes in sludge concentration due to high turbidity during or before and after typhoons. is obtained.

By the way, when we examine the relationship between the sludge interval, the amount of solid sludge deposited in the settling tank 6, and the sludge coefficient with reference to the conventional sludge treatment plant shown in FIG. Sludge solid content Dst
[Tons/day] is the injection rate Pn of flocculant and the raw water turbidity.
Tr (as sludge concentration of treated water), treated water turbidity Tt
(as sludge concentration in treated water), and raw water flow rate Qn
(flow rate of water to be treated).

That is, Dst=Qn{(Tr−Tt)+K ₁ Pn}K ₂ ×10...(1) However, K ₁ is a constant depending on the flocculant,
K ₂ is the safety factor, Qn is m ³ /day, Tr, Tt,
The value of Pn is in ppm.

Here, the volume of sludge in the settling tank is Dv
[m ³ ]/day, Dv=Dst/K ₃ × 100...(2) However, K ₃ is the sludge concentration [%] of the sediment, and the flocculant injection rate Pn is determined by the jar test etc.
, raw water turbidity Tr, treated water turbidity Tt, raw water flow rate Qn
It is required from.

By the way, if a plurality of hoppers are arranged in the sedimentation tank 6, the Dvi of the amount of sludge deposited in each hopper is
(Volume) is Dvi=bi×Dv...(3) However, here, the subscript i means the i-th hopper (the same applies hereinafter), and bi is the deposition ratio of each column of the sedimentation basin.

Therefore, the number of sludge removals Fi for each hopper
and the sludge removal interval Ti (time) are: Fi=Dvi/V...(4) Ti=1440/Fi...(5) However, V indicates the volume of each hopper, and 1440 is
It is converted into minutes as 24 (hours) x 60 (minutes).

Here, from equations (1) to (5) above, a certain hotspot Vi
To find the mud removal interval Ti, TiK ₃ /bi×K ₂ ×V×1.44×10 ⁷ /Qn{(Tr-Tt)+K ₁ Pn}=Ai×R...
(6) becomes.

However, Ai=K ₃ /bi×K ₂ R=V×1.44×10 ⁷ /Qn{(Tr-Tt)+K
₁ Pn}=V×1.44×10 ⁷ /Dst Here, in equation (6), the hopper deposition V in the R section is a plant value, and K ₁ is a process constant.
On the other hand, the flow rate Qn, raw water turbidity Tr, and treated water turbidity Tt are
It is a process measurement value. Therefore, the R portion is theoretically unique. However, as the sludge removal coefficient
Regarding the Ai part, the safety factor of _K2 , the sludge concentration of _K3 , and the deposition ratio of bi are all determined by experimental values such as the jar test. the result,
In the actual operation process, there is a possibility that the calculated value of the sludge removal interval does not match.

Therefore, by separating the sludge discharge coefficient part corresponding to the Ai part and making it possible to update it according to the actual situation, it is possible to perform automatic sludge discharge control in accordance with reality.

Next, specific examples applied based on this idea will be described with reference to the drawings.

FIG. 2 shows a block diagram of a sludge treatment plant in which the present invention is applied to an automatic sludge discharge control system. Note that the same reference numerals as in FIG. 1 refer to the same components.

The sludge discharge control device 20 includes a detector 10a that detects the turbidity of raw water arranged in the landing well 3 and
A detector group consisting of a detector 10b for detecting the flow rate of raw water flowing into the stirring basin 4 from the sedimentation basin 6 and a detector 10c for detecting the turbidity of the treated water disposed in front of the outflow trough 6a of the settling basin 6, and the accumulated sludge A quantity calculator 21,
Sludge interval calculator 22, mud drain time discriminator 23, mud drain sequencer 24, mud drain coefficient generator 25, mud drain coefficient calculator 26, normal data discriminator 27, data input command switch 28, discharge command switch 29, It is also provided with an automatic mud removal/manual switch 30.

Here, the accumulated sludge amount calculator 21 is connected to the detector 10.
The raw water flow rate value Qn detected by b and the detector 10a
From the turbidity Tr of the raw water detected by the detector 10c, the turbidity Tt of the treated water detected by the detector 10c, and the injection rate Pn of the flocculant, the average amount of sludge from the previous discharge to the present is calculated.
DNA is calculated and sent to the sludge removal interval calculator 22. On the other hand, the sludge removal coefficient generator 25
From the raw water turbidity Tr detected by 0a, calculate the raw water average turbidity Tra from the previous discharge to the present, and calculate the average turbidity Tra by referring to the built-in memory table.
Find the sludge removal coefficient Ai of a certain hopper Vi corresponding to
This is sent to the mud removal interval calculator 22.

The sludge interval calculator 22 calculates these average sludge amounts Dna
Based on the equation (6) above, the hopper is calculated from the sludge removal coefficient Ai and
The mud removal interval Ti is calculated for Vi, and the calculation result is sent to the mud removal time discriminator 23. The sludge removal time discriminator 23 uses this sludge removal interval Ti and the sludge removal sequencer 2.
When this count value TCi exceeds Ti, that is, TCi
> When Ti, the sludge ejection command signal is sent to the sludge ejection sequencer 2.
Send to 4.

Upon receiving this signal, the mud removal sequencer 24 sets each hopper 61, 62, 6 for the mud removal interval Ti.
3 and 64 discharge valves v1, v2, v3, and v4 are selectively opened. As a result, the sludge deposited there is discharged to the sludge pond 9.

By the way, the sludge removal sequencer 24 counts the time since the previous sludge removal using its built-in counter, and sends the count value TCi to the sludge removal time discriminator 23 and the sludge removal coefficient calculator 26. Here, the count value sent to the emission factor calculator 26
TCi is an element for calculating the sludge removal coefficient to be updated.

Furthermore, the storage table built into the sludge removal coefficient generator 25 is as shown in FIG. Note that the details will be described later.

Now, when it comes to automatic sludge discharge control, there are cases where it is not suitable for actual water purification operations, as in reality, there are differences in the coagulation effect due to changes in the quality of the raw water.
This increases or decreases, or the sludge concentration changes due to high turbidity during or before and after a typhoon, which may cause the hopper to fill up early or not be full even when the discharge time comes. . In situations like this, you can either actually monitor the accumulation status of the hopper on-site or install a detector, such as a sludge interface meter, to detect when a certain hopper is almost full.
This allows you to know. That is, when there is a detection signal from this detector, the sludge removal sequencer 24
The discharge command signal is not easily generated from the
On the contrary, such a situation can be known if an ejection command signal is generated even though there is no detection signal.

When a certain hopper is full but no discharge occurs, the discharge command switch 29 is pressed; however, when a discharge command signal is generated or is about to occur even though a certain hopper is not full, the discharge command switch 29 is pressed. , turn off the automatic/manual sludge removal switch 30 connected between the sludge removal time discriminator 23 and the sludge removal sequencer 24, and turn off the sludge removal sequencer 2.
4 to manual mode. Then, the discharge command signal is cut off until the hopper is full.

Next, when the hopper is full, the discharge command switch 29 is pressed down. Then, the automatic mud removal switch 30 is returned to "on" to switch to the automatic mode.

Here, the signal of the pressed discharge command switch 29 is transmitted to the sludge discharge sequencer 24 and the normal data discriminator 2.
Sent to 7. Upon receiving this signal, the sludge discharge sequencer 24 generates a discharge command signal to the corresponding hopper, opens the discharge valve of a predetermined hopper, and discharges the sludge accumulated there.

At this time, if the data input command switch 28 is "on", the output signal from the normal data discriminator 27 consisting of an AND gate of these signals is sent to the sludge removal coefficient calculator 26. Upon receiving this signal, the sludge removal coefficient calculator 26 calculates the count signal TCi of the sludge sequencer 24 and the sludge removal coefficient generator 25.
The sludge removal coefficient Ai is back calculated based on the raw water average turbidity Tra from the above equation (6), and the value is sent to the sludge removal coefficient generator 25.

When the sludge removal coefficient generator 25 receives the sludge removal coefficient Ai from the sludge removal coefficient calculator 26, it rewrites the data in the storage table to correspond to the raw water average turbidity Tra at that time.

Here, whether or not to turn on the data input command switch 28 is determined depending on whether the input data is normal or not, and this may be determined by the operator or by other normal/abnormal judgments. It may be activated by output from a device or the like.

When the data is abnormal, the data input command switch 28 is turned off, and the discharge command switch 29 simply sends only the discharge command to the sludge removal sequencer 24 to discharge the sludge accumulated in a predetermined hopper.

After being rewritten in this way, this sludge removal coefficient
The sludge removal interval TCi will be calculated from the data of Ai.

The above operations are repeated at predetermined time intervals for each hopper, and automatic sludge discharge control is sequentially performed.

Next, calculate the average raw water turbidity Tra from the previous discharge to the current calculation time, and calculate Tra/Ai as shown in Figure 3.
According to the table, based on the raw water average turbidity Tra,
An example of how the sludge removal coefficient generator 25 calculates the sludge removal coefficient Ai of a certain hopper Vi and rewrites the sludge removal coefficient Ai will be described.

FIG. 3 is an explanatory diagram of a memory table built into the sludge removal coefficient generator 25, and each column Tra, A ₁ , A ₂ , A ₃ , A ₄ arranged in the horizontal direction of the table indicates the average raw water. Turbidity Tra and corresponding hoppers 61, 62, 6
A sludge removal coefficient Ai of 3.64 is shown.

Here, when the raw water average turbidity Tra matches the value of the average raw water turbidity shown in this table, the sludge drainage coefficient corresponding to that row is A ₁ , A ₂ , Read from columns A ₃ and A ₄ .

However, when the raw water average turbidity Tra does not match the value of the raw water average turbidity Tra shown in this table, the sludge removal coefficient Ai closest to the raw water average turbidity Tra is calculated from the Tra/Ai table by proportional distribution. demand.

As an example, the average turbidity Tra of raw water is 25ppm.
For 40ppm between 50ppm, Hoppa 61
In this case, it is 2.33 when it is 25ppm, and 3.33 when it is 50ppm, so by proportionally distributing this, Ai = (40-25) x (3.33-2.33) / (50- 2
5) It is calculated as +2.33 = 2.93.

Here, the first data of this storage table is
The settings must be made in advance based on water quality calculations such as a jar test, or actual measurement data.

On the other hand, the sludge removal coefficient generator 25 rewrites the data in the memory table when receiving the sludge removal coefficient Ai from the sludge removal coefficient calculator 26, but in this case, the current raw water average turbidity Tra is When the raw water average turbidity Tra listed in the table matches, the raw water average turbidity corresponding to this in the memory table
This will be written to the corresponding sludge removal coefficient position of the Tra position and rewritten. However, when the current raw water average turbidity Tra does not match the raw water average turbidity Tra listed in the storage table, it is rewritten as follows. That is, this method reads out the previous and subsequent sludge removal coefficients that are closest to the raw water average turbidity Tra, and corrects the previous and subsequent sludge removal coefficients by performing inverse proportional allocation.

For example, if the raw water average turbidity Tra is 40ppm and the sludge removal coefficient Ai is 3.83, it is between 25ppm and 50ppm, so in memory table A1, the sludge removal coefficient Ai
The values of are 2.33 and 3.33. Therefore, 3.83−{(40−25)×(3.33−2.33)/(50
-25) +2.33}=0.9, translate this in parallel as shown in Figure 4, find 2.33+0.9=3.23 and 3.33+0.9=4.23, and write the corresponding memory table. In A1, the sludge removal coefficient
Ai value from 2.33 to 3.23 and from 3.33 to 4.23
Rewrite each.

By the way, in this embodiment, the normal data discriminator 27 is built into the sludge removal coefficient calculation unit 26, and the sludge removal coefficient Ai calculated backward from the sludge removal interval TCi and the average sludge amount Dna and the correspondence stored in the storage table are If the data is significantly different from Ai, it may be regarded as abnormal data, and the data may not be written or modified.

For example, in Figure 4, the average turbidity of raw water Tra=
At 40ppm, the Ai to be corrected is 3.83, the previous Ai
is 2.93, if the correction range is within 10% and the dead band width is 10%, then 2.93×0.1=
0.29, and the sludge removal coefficient Ai is (2.93−0.29)＜=Ai
If it exceeds the range <= (2.93 + 0.29), it is possible to avoid correction. In addition, FIG. 4 is a diagram in which the sludge removal coefficient Ai is plotted on the vertical axis and the raw water average concentration Tra is plotted on the horizontal axis.

Furthermore, in this embodiment, instead of the sludge removal command switch 29, the hopper upper limit detection signal of the sludge interface meter can be used as a trigger signal for correcting the sludge removal coefficient Ai. Also, this allows
It is also possible to check the validity of the sludge removal coefficient Ai in the manner described above.

The automatic sludge discharge control plant has been described above with a focus on the hardware, but based on this configuration, an example will be shown in which the processing of each part is executed and realized by a program. FIG. 5 shows the flow of the processing steps.

Here, this will be explained according to the flowchart shown on the left side of FIG. In this flowchart, each processing step is configured in correspondence with the processing of each part in FIG. 2, so it will be explained in connection with this.

When sludge is not being drained, for example, each process data, raw water turbidity Tr, treated water turbidity Tt, raw water flow rate Qn, and flocculant injection are calculated at a calculation cycle of x minutes (specifically, about 1 to 10 minutes). Read the rate Pn and calculate, for example, the daily accumulated sludge amount Dn at the time of calculation,
The average amount of accumulated sludge per day from the time of the previous sludge removal to the current calculation time is calculated. The steps up to this point are from step 1 to step 6, and correspond to the processing of the accumulated sludge amount calculator 21 in FIG.

Next, calculate the average raw water turbidity Tra from the previous discharge to the current calculation time, and calculate Tra/Ai as shown in Figure 3.
Using the table, find the sludge removal coefficient Ai of a certain hopper Vi that is closest to the average raw water turbidity Tra. The steps up to this point are from step 7 to step 8, and correspond to the processing of the sludge removal coefficient generator 25 in FIG.

Next, the discharge interval Ti is calculated using the average sludge amount Dna and the sludge discharge coefficient.
Calculated from Ai. This is step 9,
This corresponds to the processing of the sludge discharge interval calculator 22 in FIG.

Next, the sludge removal interval Ti for a certain hopper Vi is compared with the time count value TCi since the previous sludge removal, and when TCi>Ti and in automatic mode, a discharge command is issued to the sludge removal sequencer 24. . In addition, when in automatic mode, sludge removal automatic/manual switch 30
is “on”. This is step 10 and corresponds to the process of the sludge removal time discriminator 22 in FIG. If TCi>Ti is satisfied here, a discharge command is generated in the next step 11, and the process ends.

Note that the process also ends if TCi>Ti does not hold in step 10.

In this way, after x minutes, the same processing steps are performed again, and processing is performed for each hopper. Note that n here is a count value for a certain hopper each time this processing step is performed after the mud removal processing, and is sequentially updated in accordance with the processing every x minutes.

In this processing step, in the determination of step 2, if mud is being removed, TCi,n, Dna, and Tra are set to "0" and initialized.

Next, we will explain the manual discharge command by the operator, which is carried out in cases where the hopper is not suitable for water purification operation, such as when the hopper fills up too early or when the discharge time does not reach its full capacity. .

First, in this case, as described above, either press the discharge command switch 29 or press the automatic mud discharge switch 30.
is once turned off, the mud discharge sequencer 24 is switched to the manual mode, the discharge command signal is cut off, and the discharge command switch 29 is then pressed down. Next, this will be explained according to the flowchart shown on the right side of FIG.

First, the operator presses the discharge command switch 29 to issue a discharge command. On the other hand, a detector that detects when a certain hopper is almost full, e.g.
It receives signals from the sludge interface meter, and the operator determines whether the data is normal or not. Under normal conditions, a new emission coefficient is determined by TCi and DNA.
Start the process of calculating Ai. This is up to step 3a, and the normal data discriminator 27 in FIG.
This corresponds to the processing of the sludge removal coefficient generator 25.

Next, this new sludge removal coefficient Ai is written to the position corresponding to Tra in the memory table and corrected to the new Ai. This is step 5a and corresponds to the process of the sludge removal coefficient generator 25 in FIG. Then, the process moves to step 6a, where a discharge command is generated, and the process ends. Note that even when it is determined in step 2a that the data is abnormal, the process moves to step 6a, where a discharge command is generated and the process ends.

As described above in detail, the automatic sludge discharge/manual switch 30 is set to the manual side in advance, and in the initial stage when the washing plant starts operating, the operator uses the discharge command switch 29 to obtain the actual Ai and memorize it. It may also be written to a table. In this case, when the memory table of Ai stored in this way becomes suitable, the switch will be made to the automatic side.

In the embodiments listed above, sludge has been mainly explained; however, this invention is not limited to this, and is generally applicable to the case where substances to be deposited are accumulated and discharged, such as when extracting chemicals, etc. It can be applied to things.
In this case, the sludge drainage coefficient in the example is treated as a more general discharge coefficient, and the turbidity is similarly treated as the concentration of the deposited material. Further, although the calculation unit for calculating various values in the embodiment is specifically made up of a plurality of units, these may be integrated as one calculation unit. Therefore, including this, this is simply regarded as an arithmetic unit here.

Further, although there are multiple hoppers, there may be only one hopper, and the sedimentation tank, including the hopper, can be seen as one container. However, when it comes to general deposits, settling basins, including hoppers, are treated as containers in general, and sludge is not only a deposit but also something that accumulates and becomes sediment. . Further, the amount of accumulation is not limited to being full, but may be a predetermined amount. Furthermore, raw water is treated as a liquid to be treated, and treated water is treated as a treated liquid.

As can be understood from the above description, the present invention includes a container for depositing substances to be deposited contained in a liquid to be treated, a first container for detecting the concentration of the substances to be deposited in the liquid to be treated and a liquid after treatment; a second detector and a detector that detects the amount of inflow of the liquid to be treated into the container; the substance to be deposited is deposited in the container by mixing a flocculant or the like with the liquid to be treated; In an automatic sediment discharge control method in which a full or predetermined amount of sediment is automatically extracted from the container by calculating the amount of settled solids in the sediment, the average concentration of the liquid to be treated over a predetermined period The device is equipped with a storage section that stores discharge coefficients of the deposited material corresponding to the above, and a calculation section. Calculating an average amount of deposits in the container over a predetermined period by the calculating section, and calculating an interval for discharging the deposits from the container from the discharge coefficient read from the storage section and the average amount of deposits, According to this discharge interval, the deposited material is discharged from the container, and if the deposit is discharged at any time depending on the actual accumulation state of the deposit in the container, the previous discharge at that time The discharge coefficient is calculated backward from the period from to the current discharge, the average concentration of the liquid to be treated, and the average deposition amount, and the corresponding discharge coefficient in the storage unit for the average concentration is rewritten. , when the deposit is discharged at an arbitrary time according to the actual accumulation state of the deposit, the corresponding discharge coefficient in the storage unit is rewritten in accordance with the average concentration at that time. Therefore, even if there is a difference in the aggregation effect etc. due to a change in the quality of the liquid to be treated, the calculated value can be calculated in accordance with the actual value.
Therefore, the actual control will not become out of compliance with reality. In particular, in automatic sludge discharge control, even if the flocculation effect varies due to changes in the quality of raw water, calculated values can be calculated in accordance with the actual situation. Therefore, the actual control will not become out of compliance with reality. Furthermore, appropriate actual data can be obtained regarding changes in sludge concentration due to high turbidity during and before and after typhoons.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a sludge treatment plant to which the conventional automatic sludge discharge control system is applied, Fig. 2 is a block diagram of a sludge treatment plant to which the automatic sludge discharge control system of the present invention is applied, and Fig. 3 is an explanatory diagram of a memory table built into the sludge removal coefficient generator, which is one of the components in the embodiment of FIG.
Fig. 4 is an explanatory diagram for calculating the sludge removal coefficient for a certain average turbidity of raw water, and Fig. 5 is a flowchart of processing steps when the processing of each component in the embodiment of Fig. 2 is realized by a program. It is. 1...Sludge treatment device, 2, 20...Sludge discharge control device, 3...Water landing well, 4...Agitating pond, 5...Floc formation pond, 6...Settling basin, 7...Filtration basin, 8
...Water purification pond, 9...Sludge pond, 10a, 10b, 1
0c...Detector, 21...Deposited sludge amount calculator, 2
2...Sludging interval calculator, 23...Sludging time discriminator, 24...Sludge removal sequencer, 25...Sludge removal coefficient generator, 26...Discharge coefficient calculator, 27...Normal data discriminator, 28...Data input switch, 2
9...Sludge removal command switch, 30...Sludge removal automatic switch.

Claims (1)

[Claims] 1: a container for depositing substances to be deposited contained in the liquid to be treated; first and second detectors for detecting the concentration of the substances to be deposited in the liquid to be treated and the liquid after treatment; a detector that detects the amount of inflow into the container, mixes a flocculant or the like with the liquid to be treated, deposits the deposited material in the container, and calculates the amount of precipitated solid matter of the deposited material, In an automatic deposit discharge control method for automatically extracting deposits that are full or accumulated to a predetermined amount from the container, a discharge coefficient of the deposits is stored in correspondence to an average concentration of the liquid to be treated over a predetermined period. and a calculation unit, and the calculation unit calculates an average amount of deposited material over a predetermined period from the concentration of the liquid to be treated, the amount of the flocculant, etc., and the inflow amount of the liquid to be treated. do,
Based on the discharge coefficient read from the storage unit and this average amount of deposit, the calculation unit calculates the discharge interval of the deposits from the container, and according to this discharge interval, the deposited material is removed from the container. In addition, if the deposit is discharged at any time depending on the actual state of accumulation of the deposit in the container, the period from the previous discharge to the current discharge and the average of the liquid to be treated at that time. An automatic deposit discharge control method, characterized in that the discharge coefficient is calculated backward from the concentration and the average deposition amount, and the corresponding discharge coefficient in the storage unit is rewritten for the average concentration.