JPH0471596B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a filter number control device for a water treatment plant that controls the number of filters, and particularly to a water treatment plant flow rate. The present invention relates to a device for controlling the number of filters in a water purification plant, which operates an appropriate number of filters to protect the filter beds of each filter.

(Prior art) Generally, in the water treatment process at a water purification plant, raw water is taken in by a water intake pump, lands in a landing well, and then is guided to a settling pond, where the turbid substances and suspended matter contained in the raw water are removed by medicines. Sedimentation is separated by injection treatment, and the resulting supernatant water is led to a filtration pond via a sedimentation basin outflow conduit, where it is filtered, and then, if necessary, water is sent to general consumers through a water purification pond, a water distribution pond, etc.

By the way, in the above-mentioned water treatment plants, the supernatant water from the sedimentation basin outflow drain is usually filtered through multiple filtration basins, and each of these filtration basins is individually equipped with a filtration flow rate control valve. The filtration flow rate of the entire filtration (hereinafter referred to as the total filtration flow rate) is adjusted by adjusting the opening degree of the filtration flow rate control valve of each filtration basin according to the water treatment flow rate.
I am getting . However, in terms of filtration cleaning efficiency, etc., it is desirable to operate each filter to obtain a filtration flow rate within a predetermined filtration flow rate setting range. In this case, when the water treatment flow rate at the water treatment plant changes significantly due to some kind of accident, it is extremely difficult to operate each filtration basin to obtain the filtration flow rate within the set range.
It is necessary to operate the filter while increasing or decreasing the number of filters depending on the water treatment flow rate.

Conventionally, when the water treatment flow rate changes significantly as described above, the number of filters is increased or decreased by manually opening and closing the inlet and outlet valves of the filters.
However, when the water treatment flow rate suddenly decreases, as in the case of a water intake pump trip accident, for example, it is difficult to maintain proper operation because it takes a long time to manually shut down the filtration basin. The same thing can be said when the power is restored to the water intake pump and the water treatment flow rate suddenly recovers.

(Problem to be Solved by the Invention) Therefore, in the above-mentioned water treatment plants, when the water treatment flow rate changes suddenly, it is difficult to take appropriate measures with manual intervention, and the water level of the filtration basin may be There is a problem in that the filter bed of the filtration basin is exposed to the air due to the drop, causing secondary failure.
In other words, when regenerating the filter bed after the filter bed of the filter bed is exposed to the air and air enters the sand layer of the filter bed, the air inside the filter bed is expelled while gradually filling the filter bed with water. It needs to be cleaned and restored to its original filtration capacity. This work of filling water is generally done on-site by manipulating valves, so once air gets into the filter bed, it takes a considerable amount of time to restart the operation, and the number of filters that can filter during that time is The problem is that even if the water intake pumps are restored to power, they will not be able to process the water and the water treatment plant will have to stop functioning. Furthermore, when the water intake pump is restarted due to power restoration, the pump has a minimum discharge flow rate, so the water landing flow rate increases rapidly. As a result, when the flow rate of water arriving at the water treatment plant increases rapidly, unless the filtration flow rate is increased accordingly, the water level in the sedimentation basin outflow channel will rise rapidly, causing a situation where the sedimentation basin will overflow.

The present invention was made to solve the above-mentioned problems, and detects abnormal conditions from a total perspective of the water treatment plant process and automatically increases or decreases the number of filters to be operated. Preventing the water level of the filtration basin from dropping and preventing exposure of the filtration basin's bed.
Another object of the present invention is to provide a filter number control device for a water purification plant that prevents overflow due to an abnormally high water level in a sedimentation basin outflow conduit and ensures stable operation of the water purification plant.

[Structure of the Invention] (Means for Solving the Problems) The device for controlling the number of filtration ponds in a water purification plant according to the present invention is capable of controlling turbid substances contained in raw water taken in by a water intake pump,
Water treatment that processes floating matter through settling, filtration, etc. through an incoming well, settling basin, settling basin outflow channel, and multiple filtration basins, and controlling the number of filtration basins in operation according to the water treatment flow rate. In the field filtration tank number control device, a process state signal acquisition means for acquiring a process state signal at a pretreatment stage including the sedimentation basin outflow conduit, and an abnormal state of the water purification plant process acquired by the process state signal acquisition means are provided. When an abnormality detection signal is received from the abnormality detection means to be detected and the abnormality detection signal is received from the abnormality detection means, the control timing time is determined from the amount of water level change in the sedimentation basin outflow culvert within the observation time, and then the control timing time is Determine the number of filters to start or stop based on
A number-of-filtration determining means is provided for determining which filter to start or stop based on this number of filters.

(Function) Therefore, in the present invention, by using the above means, the abnormality detection means detects the water purification plant process based on the process state signal acquired by the process state signal acquisition means and the predetermined setting value. After examining the presence or absence of an abnormality from various viewpoints and determining the control timing time when it is determined that there is an abnormality, the number of filters to be started or stopped is determined based on this timing time, and the number of filters to be started or stopped is determined based on this timing time. The filtration basins to be started or stopped are determined in sequence, and the corresponding filtration basins are started or stopped.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram showing one embodiment of the device of the present invention, and this device is roughly divided into a water purification plant 10 and a filter number control device 20.

As is well known in the art, the water purification plant 10 takes in raw water 11 with water pumps 12, . . .
3. Remove turbid substances, suspended matter, etc. contained in the raw water while passing through the sedimentation basin 14, sedimentation basin outflow drain 15, multiple filtration basins 16, ... and water purification basin 17, etc.,
It is also a facility that performs a series of water purification operations, such as filtering and cleaning and then sending water to consumers using a water pump 18. In addition, a sedimentation pond outflow weir of a predetermined height is provided between the sedimentation pond 14 and the sedimentation pond outflow culvert 15,
The flow rate of the sedimentation basin 14 overflows the sedimentation basin outflow weir and is sent to the sedimentation basin outflow culvert 15.

On the other hand, the filter number control device 20 is provided with process status signal acquisition means for acquiring status signals of the target process. This process status signal acquisition means acquires a process status signal for determining the operating status of the target process by installing a detector according to the acquisition purpose at a desired location, and specifically, for example, a water intake pump. 12 operating units S1, the landing flow rate value S2 of the landing well 13 (or the sedimentation basin total inflow flow rate value S3 of the sedimentation basin 14), the sedimentation basin outflow conduit water level S4 of the sedimentation basin outflow conduit 15, etc. are acquired.

Further, the filter number control device 20 is provided with an abnormality detection means for detecting an abnormal state of the target process from each of the signals S1 to S4. This abnormality detection means is a water intake pump stop detection means 2 that compares the number of water intake pumps in operation S1 and a set value S1' for the number of water intake pumps in operation and detects an abnormality in the number of water intake pumps in operation.
1, and the landing flow rate S2 or the total sedimentation pond inflow flow rate S
3 and a flow rate change set value S2', and detects an abnormality when the inflow flow rate to the filtration basin 16 of the water purification plant changes by more than the flow rate change set value.
2, water level change abnormality detection that compares the sedimentation basin outflow conduit water level S4 and the sedimentation basin outflow conduit water level change set value S4' and detects an abnormality when the water level of the sedimentation basin outflow conduit changes by more than the set value within a unit time. It is constituted by means 23 and the like. In addition, these water intake pump stop detection means 21, water landing flow rate abnormality detection means 22, and water level change abnormality detection means 23 process state signals S1 to S.
4 are taken in parallel to determine whether there is an abnormal state, but since the sedimentation basin outflow conduit water level S4 most reflects the state of the filtration flow rate, at least the water level change abnormality detection means 23 is used to detect the sedimentation basin outflow conduit water level S4. It is necessary to obtain the outflow channel water level S4 and determine the abnormal state of the process.

The intake pump stop detection means 21, the water landing flow abnormality detection means 22, and the water level change abnormality detection means 23
These outputs are sent to the control timing determining means 24. The control timing determining means 24 has a function of determining the control timing based on the abnormality detection signal from any one of the means 21 to 23 and the sedimentation pond outflow channel water level S4. Reference numeral 25 denotes a starting/stopping pond number determining means which receives a control timing signal from the control timing determining means 24 and determines the number of ponds to be started or stopped based on the sedimentation pond outflow channel water level S4, and the activated or stopped pond number determined here is The stop pond number signal is introduced into the start/stop pond determining means 26. In addition to the number of ponds to be started or stopped, the start/stop pond determining means 26 receives input of the valve opening/closing state signal S11, filtration signal S12, filtration flow rate S13, and pond determination standard setting value S14 of each filter basin 16,... , the pond number of the filtration basin to be started or stopped, and the state target value of the filtration basin 16 of the relevant pond number (for example, starting or stopping)
Determine and output. In addition, these means 21-2
6, etc., which will be described later, can be realized by software processing using a control computer or by a hardware configuration.

Reference numeral 30 denotes an operating end control unit, which sends an open/close command signal S15 to the valve installed in the corresponding filter basin 16 by sequence control, for example, according to the state target value from the start/stop basin number determining means 26. The output is output and adjusted to control the state of the filter 16 to a target state value, and is realized using, for example, a sequence controller. Note that signal input/output to the target process is performed using a data transmission device. In the figure, 31 is a flow meter, and 32 is a water level meter.

Next, before explaining the operation of the device configured as described above, the necessity of operating the device using an appropriate number of filters 16 based on the water level relationship of the water purification plant will be explained using Fig. 2. . Now, the water level h of the sedimentation basin outflow channel 15 is the water treatment flow rate of the water treatment plant, Q,
When the filtration flow rate of the filtration basin 16 is q, it changes based on the following formula: ∂h/∂t=1/A(Q− _o 〓 ⁱ⁼¹ qi) (1). However, n is filtration pond 1
6 in parallel, A (m ² ) is the area of the sedimentation basin outflow conduit 15. Therefore, when the sum _o 〓 ⁱ⁼¹ qi of the filtration flow rate of each filtration basin 16 is large compared to the water treatment flow rate Q of the water purification plant, the water level h of the sedimentation basin outflow culvert 15 decreases,
Conversely, when the sum _o 〓 ⁱ⁼¹ qi of the filtration flow rate of each filtration basin 16 is small, the water level h of the sedimentation basin outflow culvert 15 rises. Further, the water treatment flow rate Q of the water treatment plant is approximately equal to the total inflow flow rate Q' of the sedimentation pond, which is approximately equal to the landing flow rate. Therefore, if the landing flow rate suddenly decreases for some reason, the water treatment flow rate Q and the settling basin outflow channel water level h also decrease rapidly. If the water level h of the sedimentation basin outflow channel falls below the specified value, the water level of the filter bed 16a of the filtration basin 16 is generally made higher than the water level of the water purification basin 17, so the filter bed 16a may come into contact with air. Gender comes out.
Therefore, when the water treatment flow rate Q suddenly decreases, it is necessary to reduce the number of filtration ponds in operation to prevent a sudden drop in the sedimentation basin outflow water level h. In addition, filter bed 1
When air enters the sand layer 6a, all the filters 16
The filtration capacity will not be restored unless the air is gradually filled with water and the air is expelled from the filter bed 16a, and it will take a considerable amount of time to restart the water purification plant.

On the other hand, when the water intake pump 12 is restarted due to power restoration at the water intake pump station, etc., the minimum discharge flow rate is determined for the pump 12, so the landing flow rate increases accordingly. As a result, the water treatment flow rate Q at the water purification plant also increases rapidly. When the water treatment flow rate Q rapidly increases, the water level h of the sedimentation basin outflow conduit 15 increases rapidly, and as a result, the sedimentation basin 14 overflows. Therefore, when the water treatment flow rate Q suddenly increases, it is necessary to increase the number of filtration basins 16 to prevent a sudden increase in the sedimentation basin outflow water level h.

As described above, in this apparatus, it is necessary to operate an appropriate number of filters 16 according to the water treatment flow rate of the water purification plant.Hereinafter, the operation of the apparatus of the present invention will be explained with reference to FIG. 3. When the device starts operating by turning on the power, as shown in step ST1, the water intake pump stop detection means 21, the water landing flow abnormality detection means 22, and the water level change abnormality detection means 2 are activated.
3 takes in the number of intake pumps in operation S1, the landing flow rate S2 (or the total inflow flow rate of the sedimentation basin S3), and the sedimentation basin outflow channel water level S4, and sets the respective set values S1' and S.
2, compare with S4'. Here, if the number S1 of water intake pumps in operation is not equal to the set value S1', the water intake pump stop detection means 21 determines that a sudden change has occurred in the water treatment flow rate at the water purification plant, and outputs an abnormal signal. Further, the landing flow rate abnormality detection means 22 outputs an abnormal signal when the change in the landing flow rate S2 or the total inflow flow rate S3 of the sedimentation basin is equal to or larger than the flow rate change set value S2'. The water level change abnormality detection means 23 outputs an abnormal signal when the sedimentation pond outflow channel water level S4 within a unit time is equal to or higher than a set value S4'.

When an abnormal signal is output from any one of the detection means 21 to 23 as described above, the control timing determination means 24 performs steps ST2 to ST4 to determine the timing for starting or stopping the filter 16. decide. In other words, the control timing determining means 24 sets the water level of the sedimentation basin outflow channel at time t from the water level meter 32 to h(t) and the control water level upper limit set value.
If HL and control water level lower limit set value LL, then step
In ST2, it is determined whether the relationship h<LL or HL<h...(2) exists, and if the above relationship exists, the process moves to step ST3 and the amount of change in the water level of the sedimentation basin outflow channel within the observation time DT is determined. Calculate DH.

DH-h(t)-h(t-DT)...(3) Then, once the amount of change DH in the water level of the sedimentation basin outflow channel is determined, the time T is determined.

T=｜(DT/DH)｜・α……(4) However, α is a control parameter (constant).

Once the time T has been determined in step ST3, if the filter 16 has not been started or stopped during the past time T based on step ST4, it is determined that it is the control timing, and a control timing signal is output. . If the filter 16 has been started or stopped within the past time T, no control timing signal is output.

Here, the start/stop filter number determining means 25 determines the number of filter filters to be started or stopped upon receiving the control timing signal (step ST5). This number of starting or stopping ponds △N is: (a) When the filter starts △N = (DH・A)/(DT・Qs)・β ……(5) (b) When the filter stops △N=(DH・A)/(DT・Qe)・β ...(6) It is expressed as. In the above formula, A is the sedimentation basin outflow conduit area, Qs is the average filtration flow rate at the time of starting the filtration basin, and Qe
is the average value of the filtration flow rate when the filtration basin is stopped, and β is the control parameter.

When the number of starting/stopping ponds ΔN is determined as described above, the starting/stopping pond determining means 26 determines the filtration pond to be started or stopped based on the determined number of ponds ΔN in steps ST6 to ST8. do. This determination of the filter is determined by the valve opening/closing status signal S1 of each filter 16.
1. Take in the filtration signal S12, filtration flow rate S13, pond determination standard set value S14, etc., and use these signals S
From 11 to S13, it is determined for how long which filter 16 has been stopped, in operation, or in a fatigued state, and for example, if the stoppage time exceeds the standard set value S14, the filter with the longest stoppage time is selected. Pond 1
6 to the short filters 16, and sends a filter activation command (when ΔN>0) to the operating end control unit 30 for these ΔN filters 16.

On the other hand, to determine the stop ponds, filters 16 are sequentially selected for the number of △N filters starting from the filter 16 with the longest operating time, and a filter stop command is issued to these △N filters 16 (for △<0). time) is sent to the operating end control section 30. Here, the operating end control unit 30 gives an overstart command or a filter stop command to the determined filter 16 to start or stop the filter 16, and always keeps the filtration flow rate of each filter 16 within the set range. Run filtration.

In addition, to explain with a specific example, for example, due to a sudden decrease in the landing flow rate, the landing flow abnormality detection means 2
When an abnormal signal is output from 2, the control timing determining means 24 receives this abnormal signal and determines the observation time.
Assuming that the sedimentation pond water level changes by DH1 during DT, the time T1 can be obtained from equation (4) as follows: T1=(DT/DH1)・α...(4)′. From this equation, if the change in the water treatment flow rate at the water treatment plant is large, the value of T1 will be small, and conversely, if the change in the water treatment flow rate at the water treatment plant is small, the value of T1 will be small.
The value of increases. This means that when there are large changes in the water treatment flow rate at a water treatment plant, the filtration
On the other hand, when the change in the water treatment flow rate at the water purification plant is small, the filtration basin 16 is started or stopped at long intervals. In particular, T1
The value of becomes even smaller and becomes less than the control period.
In this case, the number ΔN1 of the filters 16 to be stopped is calculated from the above equation (6) as follows: ΔN1=(DH1・A)/(DT・Qe)・β (6)′. In other words, if there is a large change in the water treatment flow rate at the water treatment plant, the number of filtration ponds to be started or stopped △N
is controlled so that the filtration flow rate increases and the filtration flow rate changes significantly.

Therefore, according to the embodiments described above, when it is detected that a large change has occurred in the water treatment flow rate of the water treatment plant from the process status signal such as the water level of the sedimentation pond outflow conduit, for example, the water level of the sedimentation pond outflow conduit, etc. The number of filters to be automatically started or stopped is determined based on the factors, and the filters 16 corresponding to the number of filters are selected and started or stopped based on the length of the stop time or operating time of each filter 16. As a result, the filter 16 can be started or stopped in a short period in response to large fluctuations in the water treatment flow rate at the water treatment plant, and the filter cleaning is always performed with the number of active filter basins commensurate with the water treatment flow rate. Therefore, there is no need to worry about the filter bed 16a of the filter basin 16 coming into contact with the air, and stable operation can be ensured. In addition, since only the determined number of filters are selected from among the filters 16 and controlled to start or stop, taking into account the operating state, the operating time of each filter 16 can be averaged, and from the point of view of filtration capacity, etc. is also desirable.

Note that the present invention is not limited to the above embodiments. For example, as shown in Figure 4, each filtration basin 1
6,... are equipped with filtration flow rate control valves 41,..., each filter 16 is provided with a filtration flow rate control device 42,..., and performs, for example, PID control based on the filtration flow rate S13 and the filtration flow rate target value S41. and
The obtained operation output controls the filtration flow rate control valve 41.
You may control the filtration flow rate of each filtration basin 16 so that it becomes a filtration flow rate target value by adjusting the opening degree of the filtration basin 16 .

According to the configuration of such an embodiment, the filtration flow rate qi of each filter basin 16 is controlled to be the filtration flow rate target value S41 by the PID calculation control of the filtration flow rate control device 42, and as a result, the above equation (1) The term Σqi is a constant value, and as mentioned above, the number of ponds to be started or stopped is determined according to the water treatment flow rate of the water treatment plant, and each filter basin 16 is selected as appropriate based on this number of ponds. It performs start or stop control.

Next, FIG. 5 is a block diagram illustrating another embodiment of the apparatus of the present invention. That is, in this embodiment, when the filtration flow rate control valve 41 is installed in the filtration basin 16, a water level control device 51 is provided in addition to the filtration flow rate control device 42, and this water level control device 51
In each filter basin 16, based on the sedimentation pond outflow conduit water level S4 and the sedimentation basin outflow conduit water level target value S51
The filtration flow rate target value S41 may be automatically determined and supplied to the filtration flow rate control device 42. In other words, the water level control device 51 increases the filtration flow rate target value S41 when the water level of the sedimentation pond outflow drain rises, and conversely acts to decrease the filtration flow rate target value S41 when the water level of the sedimentation basin outflow drain decreases. while controlling the filtration flow rate.

Now, the target value of filtration flow rate for No. I filtration basin 16i is
Let it be Qref-i. Since there are physically upper and lower limits to the filtration flow rate of this filtration basin 16i, the filtration flow rate target value
Qref-i must satisfy the following formula.

Qmin-i≦Qref-i≦Qmax-i ...(7) However, Qmin-i is the minimum filtration flow rate target value of No. I filter 16i, and Qmax-i is the maximum filtration flow rate target value of No. I filter 16i. be. Therefore, in the water level control device 51, the filtration flow rate target value Qref-i calculated based on the water level of the sedimentation basin outflow channel is set to the upper limit value Qmax-.
Qref-i is limited to the upper limit Qmax-i or the lower limit Qmin-i when it exceeds the upper limit Qmin-i or the lower limit Qmin-i, that is, when the above equation (7) is not satisfied. As a result, the term Σqi in equation (1) becomes ΣQmax−
i (or the lower limit value Qmin-i), the water level in the sedimentation basin outflow channel will change depending on the amount of change in the water treatment flow rate that exceeds this value, and the operating filtration pond will change depending on the water treatment flow rate at the water treatment plant. The number can be controlled.

In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As described in detail above, according to the present invention, when a process abnormality is detected from various process status signals of a water treatment plant, it is possible to detect a The number of filters to start or stop is determined while varying the control timing time, so even when the water treatment flow rate at the water treatment plant fluctuates significantly, the appropriate number of filters can be determined while considering stable and safe operation. Therefore, each filtration basin can be continuously operated in an appropriate state without manual intervention, and a drop in the water level of the filtration basin can be avoided and the exposure of the filter bed of the filtration basin can be prevented. It is possible to provide a filter number control device for a water purification plant that can prevent overflow due to abnormally high water levels and ensure stable operation of the water purification plant.

[Brief explanation of the drawing]

Figures 1 to 3 are shown to explain one embodiment of the device of the present invention. Figure 1 is a configuration diagram of the entire device, and Figure 2 is a schematic diagram explaining the relationship between water levels in a water purification plant. , FIG. 3 is a processing procedure diagram explaining the operation of the apparatus of the present invention, and FIGS. 4 and 5 are configuration diagrams showing other embodiments in which a filtration flow rate regulating valve is provided, respectively. 10...Water treatment plant, 12...Water intake pump, 13...
... Water landing well, 14 ... Sedimentation pond, 15 ... Sedimentation pond outflow channel, 16 ... Filtration pond, 20 ... Filter number control device, 21 ... Water intake pump stop detection means, 22 ...
... Water landing flow rate abnormality detection means, 23 ... Water level change abnormality detection means, 24 ... Control timing determination means, 2
5... Means for determining the number of starting/stopping ponds, 26... Starting/stopping
Stop pool determining means, 30... operating end control unit, 41...
...filtration flow rate control valve, 42...filtration flow rate control device,
51...Water level control device.

Claims (1)

[Scope of Claims] 1. Processing water such as turbid substances, suspended matter, etc. contained in raw water taken in by a water intake pump through sedimentation, filtration, etc. through a landing well, a sedimentation pond, a sedimentation pond outflow drain, and a plurality of filtration ponds, In a filter number control device for a water purification plant that increases or decreases the number of filters operated according to the water treatment flow rate, a process status signal acquisition means for acquiring a process status signal of a pretreatment stage including the sedimentation basin outflow conduit. and an abnormality detection means for detecting an abnormal state of the water purification plant process using the process state signal acquired by the process state signal acquisition means; A control timing time is determined from the amount of water level change in the sedimentation basin outflow conduit, the number of filtration ponds to be started or stopped is determined based on this control timing time, and filtration to be started or stopped based on this number of ponds. A device for controlling the number of filtration ponds in a water purification plant, comprising: means for determining the number of filtration ponds for determining the number of filtration ponds. 2. The process status signal acquisition means is configured to detect at least the water level of the settling basin outflow drain among the number of operating water intake pumps, the landing flow rate of the landing well, the total flow rate of the settling basin into the settling basin, and the water level change of the settling basin outflow drain. A filter number control device for a water purification plant according to claim 1, which obtains changes. 3. The means for determining the number of filtration ponds determines the number of ponds using data such as the amount of change in the water level of the sedimentation basin outflow channel and the area of the sedimentation basin outflow conduit within a certain observation time. A device to control the number of filtration ponds at a water treatment plant. 4. The filtration basin number determination means grasps the stoppage or operating status of the filtration basins based on the number of basins, using the valve opening/closing state signal, filtration signal, filtration flow rate, basin determination standard set value, etc. of each filtration basin, The device for controlling the number of filters in a water purification plant according to claim 1, which sequentially determines which filters to start or stop based on the stop time and operation time.