JP6132104B2 - How to clean the filter - Google Patents

Description

The present invention relates to a filter cleaning method using filtration equipment including a plurality of filters, and using the filtered water treated by other filters as cleaning water.

Conventionally, in a filtration facility provided with a plurality of filters, a filtration method for storing filtered water treated by the filtration facility and using the filtered water as washing water at the time of washing the filter has been used. However, when this cleaning method is used, a storage tank for storing the filtered water as the cleaning water is necessary, and the installation area of the filtration equipment increases, and the management burden of the storage tank, the backwash pump, etc. increases. It was.

Similarly, in a filtration facility equipped with a plurality of filters, a filtration device that uses filtered water treated by other filters as washing water is disclosed in Patent Document 1.
In addition, Patent Document 2 proposes a filtration system that secures filtered water by increasing the flow rate of raw water from the normal flow rate with a filtration device that uses filtered water as washing water.

JP2003-93808 JP2013-166087A

In the filtration device of Patent Document 1, a storage tank for storing filtered water as washing water is not necessary, but the amount of filtered water treated by another filter is used for washing because the inflow of raw water is reduced. The amount of cleaning water used may not be sufficient. Therefore, it has been necessary to install a replenishment washing water tank and a replenishment water pump for feeding washing water from the replenishment washing water tank.

In the filtration system of Patent Document 2, it is not necessary to install a replenishment washing water tank or the like. However, in order to secure the amount of washing water, the inflow of filtered raw water is increased, and even if the inflow of filtered raw water changes In order to be able to do so, the raw filter water storage tank which stores raw filter water temporarily is required.

The present invention is a filter washing method that uses the filtrate water of another filter for washing the filter, and is a filtration facility that does not require a washing water storage tank. It was made to solve.
Moreover, this invention provides the washing | cleaning method which does not require the filtration raw water storage tank used by patent document 2 in addition to the said problem.

Filtration water that has passed through the filter media of the filter and connected to multiple filters in parallel with multiple filters that filter the raw water through the filter medium layer formed from the floatable filter medium. In the washing method that uses the filtered water from the other filter as washing water for washing one filter in a filtration facility having a treated water outflow passage that discharges the water from the water level meter above the other filter during filtration In accordance with the calculated filtrate water level, the opening of the wash water gate for changing the amount of wash water supplied from the lower side of one filter from the treated water outflow path is determined . If the actual filtration tank water level of the filter is higher than the reference filtration water level, wash water is passed through the washing water gate at the reference gate opening, and if the actual filtration tank water level of other filters is less than the reference filtration tank water level, washing is performed. Set the water gate to a predetermined gate opening smaller than the reference opening, and from above one filter By supplying wash water continuously until the total amount of wash sewage discharged overflow reaches a predetermined amount, stable washing can be performed without the need for a wash water storage tank , and a pump for washing, etc. The power of is not necessary. Further, even if the inflow of the raw water changes during the cleaning, the cleaning water can be always supplied, so that continuous cleaning can be performed.

Each filter has a cleaning drainage channel that discharges cleaning sewage, calculates the overflow water level from the actual filtration tank water level of the one filter to the cleaning drainage channel, and calculates the actual cleaning drainage amount of cleaning sewage, Since the total amount of cleaning waste water can be accurately calculated by integrating the actual cleaning waste water amount and calculating the actual total cleaning waste water amount, a stable cleaning effect can be obtained.

Compare the actual water flow rate calculated from the actual filtration tank water level of the other filter and the opening of the cleaning water gate with the actual water flow rate calculated from the actual filter tank water level of the one filter. If the amount of cleaning wastewater is greater than or equal to the amount of inflow of cleaning water, decrease the opening of the cleaning water gate in steps, and if the amount of actual cleaning wastewater is less than the amount of inflow of cleaning water, increase the opening of the cleaning water gate in steps. Therefore, it is possible to determine an error in the inflow amount of the cleaning water by adjusting the opening degree of the cleaning water gate, and to eliminate the excess or deficiency of the actual cleaning water discharge amount, and to obtain an optimum value for cleaning.

The filtration facility of the present invention includes a plurality of filters, and in order to wash the filters while controlling the amount of filtrate water used by other filters, a storage tank for storing the wash water is required. In addition, pumps and other equipment are not required to use the water level difference for supplying cleaning water.
Even if the inflow of raw water fluctuates, the amount of cleaning water used is controlled by adjusting the opening of the cleaning water gate, and the lack of filtered water is prevented.
By controlling the opening of the wash water gate as in the present invention, a certain amount of filtered water can be secured at all times while using a portion of the filtered water for the wash water, so that the filtrate recovery rate can be stabilized. .
Moreover, since the washing is completed by detecting that a predetermined amount of washing water has passed through the filtration tank, the washing effect can be stabilized. If the cleaning effect is stabilized, the number of cleanings can be reduced, leading to energy saving.

It is a schematic explanatory drawing of the filtration equipment used for the washing method concerning the present invention. Similarly, it is sectional drawing of the filtration installation in a filtration process. Similarly, it is sectional drawing of the filtration equipment in the water draining process. Similarly, it is sectional drawing of the filtration installation in a stirring process. Similarly, it is sectional drawing of the filtration equipment in a drainage process. It is a flowchart of the washing | cleaning method of this invention. It is a flowchart of the washing | cleaning method which concerns on other embodiment of this invention.

FIG. 1 is a schematic explanatory view of a filtration facility used in the cleaning method according to the present invention.
In the cleaning method of the present invention, a plurality of upward flow filters are used. The filter tank 1 of the filter is provided with a filter medium receiver 2 for preventing the filter medium from flowing out, and filtration is performed with a filter medium layer 3 made of a floatable filter medium below the filter medium receiver 2.

A pressure regulating tank 4 is provided adjacent to the filtration tank 1, and raw water flows into the pressure regulating tank 4.
The pressure regulating tank 4 has an opening penetrating from the lower side of the pressure regulating tank 4 to the lower side of the filter medium layer 3 of the filtration tank 1, and the raw water of the pressure regulating tank 4 is supplied to the lower side of the filter medium layer 3 of the filtration tank 1. A raw water inflow gate 5 is provided in an opening penetrating the pressure regulating tank 4 and the filtration tank 1.

The raw water that has flowed into the filtration tank 1 passes through the filter medium layer 3 formed in the filter tank 1 and is filtered, and is discharged from the upper part of the filter medium receiver 2 to the treated water outflow passage 6 adjacent to the filter tank 1. The plurality of filters discharges filtrate to the common treated water outflow passage 6. The filtered water discharged to the treated water outflow path 6 is conveyed to the next process. The treated water outflow passage 6 is shared adjacent to a plurality of filters, and collects the filtrate discharged from each filter. The treated water outflow path 6 has an outlet for supplying filtrate to the next process from a position corresponding to the filter medium receiver 2 of the filtration tank 1 and a bottom at a position corresponding to the lower end of the filter medium layer 3 .

A washing pipe 7 communicates from the bottom of the treated water outflow path 6 to the lower part of the filtration tank 1, and a part of the filtered water discharged to the treated water outflow path 6 is used as washing water for the filter medium layer 3. A cleaning water gate 8 is disposed in the cleaning pipe 7.
An air tube 9 for stirring and washing the filter medium layer 3 is disposed below the filter medium layer 3. At the time of washing, the filter medium layer 3 is agitated by the air supplied from the air pipe 9, and the washing water is caused to flow into the filtration tank 1 due to the difference in water level between the treated water outflow path 6 and the filtration tank 1 and the washing sewage is discharged. Therefore, it is only necessary to open the washing water gate 8 without requiring the power of a pump or the like.
In addition, the speed at which the washing water moves upward in the filtration tank 1 is proportional to the water level (filtered water amount) of the treated water outflow passage 6.

Between the filter medium receptacle 2 of the filtration tank 1 and the treated water outflow passage 6, there is an opening penetrating to the washing drainage passage 10. A sewage discharge gate 11 is provided in the opening. A cleaning drain pipe 12 is connected from below the cleaning drainage channel 10, and the cleaning drain pipe 12 discharges cleaning sewage after cleaning the filter medium. The washing drainage channels 10 of a plurality of filters may be connected and shared.
At the time of washing, washing water flows into the filtration tank 1 from the treated water outflow path 6, and the washing sewage level in the filtration tank 1 being washed rises and is discharged to the washing drainage path 10. The washing water is replaced and washing is performed. The sewage discharge gate 11 is closed during the filtration process.

The cleaning drain pipe 12 and the cleaning pipe 7 are communicated with each other through a communication pipe 13, and a drain gate 14 is disposed in the communication pipe 13. The communication pipe 13 connected to the cleaning pipe 7 is connected to the cleaning pipe 7 on the filtration tank 1 side from the cleaning water gate 8.
A water level meter 15 is disposed above the filtration tank 1 and the pressure regulating tank 4.

A method from filtration to washing in the filtration facility will be described in detail with reference to FIGS.
FIG. 2 is a cross-sectional view of the filtration equipment during the filtration process.
The raw water inflow gate 5 is opened, and the sewage discharge gate 11, the washing water gate 8, and the drain gate 14 are closed.
The raw water that has flowed into the pressure adjusting tank 4 flows into the filter tank 1 through the opening at the bottom of the filter tank 1, and passes through the filter medium layer 3 made of a floatable filter medium formed in the filter tank 1 in an upward flow. While the raw water passes through the filter medium layer 3, SS in the raw water is captured and removed. The filtered water that has passed through the filter medium layer 3 is discharged from above the filtration tank 1 to the treated water outflow passage 6. The filtered water discharged to the treated water outflow passage 6 is continuously conveyed to the next process, and the other part is used as cleaning water.

As filtration progresses, the trapped water loss rises due to the captured SS, and the water level in the pressure regulating tank 4 rises accordingly. When the water level in the pressure regulating tank 4 rises to a predetermined water level, the process switches to the water draining process for cleaning the filter medium layer 3.
Filters other than the filter switched to the draining process use the filtered water as washing water and continue the filtering process. The filtered water is subsequently conveyed to the next process.

FIG. 3 is a cross-sectional view of the filtration equipment during the water draining process.
The drainage gate 14 is opened, and the raw water inflow gate 5, the sewage discharge gate 11 and the washing water gate 8 are closed.
The raw water inflow gate 5 is closed to stop the raw water inflow. The filtration tank 1 is drained from the washing pipe 7 connected to the lower side of the filtration tank 1 through the communication pipe 13 and the washing drain pipe 12. When the water level of the filtration tank 1 that performs washing falls below the filter medium receiver 2, the drain gate 14 is closed, the draining process is completed, and the process is switched to the stirring process.
The water draining step is intended to facilitate the stirring of the filter medium layer 3 compacted by the filter medium receiver 2 by the filtration pressure in the air stirring of the next process and to discharge the sediment having a relatively large specific gravity that has settled in the lower part of the filter tank 1. It is.

FIG. 4 is a cross-sectional view of the filtration equipment during the stirring process.
The raw water inflow gate 5, the washing water gate 8, the drainage gate 14, and the sewage discharge gate 11 are closed.
In the stirring step, air is supplied from the air pipe 9 provided at the lower part of the filter medium layer 3 to stir the filter medium layer 3 formed by the filtration pressure, and the trapped SS and the like are dispersed from the filter medium by bringing the filter medium into a fluid state.
After the stirring of the filter medium layer 3 is completed, the process switches to the drainage process. Moreover, you may open the sewage discharge gate 11 in preparation for the next process during this process.

FIG. 5 is a cross-sectional view of the filtration facility during the drainage process.
The sewage discharge gate 11 and the wash water gate 8 are opened, and the raw water inflow gate 5 and the drain gate 14 are closed.
In the drainage process, the filter medium is regenerated and the wash water gate 8 is opened while the filter medium is agitated and flowed with air in order to discharge the captured SS and the like out of the system, and the treated water in the treated water outflow passage 6 from the lower part of the filtration tank 1. Is passed through the filtration tank 1 as washing water. Since cleaning water flows into the filtration tank 1 from below, the cleaning sewage rises, and the cleaning sewage is discharged from the sewage discharge gate 11. Therefore, the cleaning sewage in the filtration tank 1 is replaced with the cleaning water.
Since the cleaning water supply uses the difference in water level, no power such as a pump is required.

Moreover, the wash water used for washing | cleaning uses the filtered water of the treated water outflow path 6 common to a some filter. Controlling the amount of filtered water used as washing water so that it can be used as washing water while continuously supplying filtered water to the next process, it is necessary to provide equipment that can always supply washing water and store washing water. do not do. Washed sewage is extracted from the opened sewage discharge gate 11 and flows out to the washing drainage channel 10. After the cleaning sewage is discharged from the cleaning drain pipe 12 below the cleaning drainage channel 10, the cleaning is terminated and the process is switched to the filtration process.

FIG. 6 is a flowchart of the cleaning method of the present invention.
A reference value used for cleaning is set in advance before cleaning.
A certain amount of washing water is used for washing in order to obtain a stable washing effect. The amount of cleaning water for stable cleaning is defined as a reference total cleaning drainage amount QW _-SET .

1A. When the water level in the washing start pressure adjustment tank 4 exceeds the specified value, the filter starts washing. That is, the process proceeds from the filtration step described above to the draining step through the water draining step and the stirring step. Several other filters continue filtering. Hereinafter, it becomes a flowchart of the control method in a discharge process.

1B. Measurement of filtration tank water level In a filter during filtration, the water level measured in the filtration tank 1 is defined as an actual filtration tank water level H1. In addition, what is measured at this time may measure and compare the water level of the overflow part to the treated water outflow channel 6.

1C. The amount of filtrate water currently obtained can be judged by the water level of the filtration tank 1 during filtration tank water level comparison filtration. As described above, the amount of filtered water is proportional to the washing rate. When the cleaning water is supplied as the reference gate opening degree _GO-STD with the cleaning water gate 8 set in advance at the normal raw water inflow amount, the upward speed of the cleaning water is set as the reference cleaning speed. Therefore, the water level of the filtration tank 1 for obtaining the amount of filtered water necessary for washing at the reference washing speed is defined as a reference filtration tank water level H1 _STD .
In the flowchart 1C, the actual filtration tank water level H1 and the reference filtration tank water level H1 _STD are compared. The opening degree of the cleaning water gate 8 is set based on the water level H1 of the actual filtration tank, and the supply amount of the cleaning water is controlled.
When the actual filtration tank water level H1 is equal to or higher than the reference filtration tank water level H1 _STD , the flow proceeds to the flowchart 1D and the opening degree of the washing water gate 8 is set.
When the actual filtration tank water level H1 is less than the reference filtration tank water level H1 _STD , the flow proceeds to the flowchart 1E and the opening degree of the washing water gate 8 is set.

1D. Since the actual filtration tank water level H1 is equal to or higher than the reference filtration tank water level H1 _{STD in the} cleaning water gate setting flowchart 1C, a sufficient amount of filtered water can be secured. Accordingly, since the cleaning may be performed at the reference cleaning speed, the opening degree of the cleaning water gate 8 is set to a preset reference gate opening degree _GO-STD .
After the opening degree of the cleaning water gate 8 is set to the reference gate opening degree _GO-STD , the process proceeds to the flowchart 1F.

1E. Since the actual filtration tank water level H1 is less than the reference filtration tank water level H1 _{STD in the} washing water gate setting flowchart 1C, the discharge amount of filtrate water decreases, and the washing water becomes insufficient when washing is performed at the reference washing speed. Accordingly, the opening degree of the cleaning water gate 8 is set to a predetermined gate opening degree G _O-SET smaller than the reference gate opening degree G _O-STD to reduce the supply amount of the cleaning water. In order to reduce the amount of filtered water used as the washing water, the washing water in the treated water outflow passage 6 can be continuously supplied without being depleted. The gate opening degree G _O-SET is set so as to vary in proportion to the actual filtration tank water level H1.
The gate opening degree G _O-SET may be set to decrease stepwise.
After the opening degree of the washing water gate 8 is set, the process proceeds to the flowchart 1F.

1F. Calculation of the amount of washing wastewater The water level measured in the filtration tank 1 during washing is defined as an actual filtration tank water level H2. From the actual filtration tank water level H2, an actual cleaning drainage amount QW _-OUT discharged from the cleaning drainage channel 10 is calculated.

1G. Accumulated actual cleaning wastewater amount QW _-OUT is integrated to calculate the actual total cleaning wastewater amount ΣQW _-OUT .

1H. Comparison of total cleaning wastewater amount Actual total cleaning wastewater amount ΣQ _W-OUT is compared with reference total cleaning wastewater amount QW _-SET .
When the actual total cleaning waste water amount ΣQ _W-OUT is equal to or larger than the reference total cleaning waste water amount Q _W-SET , the process proceeds to the flowchart 1I to end the cleaning.
When the actual total cleaning drainage amount ΣQ _W-OUT is less than the reference total cleaning drainage amount QW _-SET , the process proceeds to the flowchart 1B and the cleaning is continued.

1I. The washing water gate 8 after washing is closed and filtration is resumed.

FIG. 7 is a flowchart of a cleaning method according to another embodiment of the present invention.
A reference value used for cleaning is set in advance before cleaning. Since the definition of the setting value described above is the same, the description thereof is omitted here.

2A. When the water level in the washing start pressure adjustment tank 4 exceeds the specified value, the filter starts washing. That is, the process proceeds from the filtration step described above to the draining step through the water draining step and the stirring step. Several other filters continue filtering. Hereinafter, it becomes a flowchart of the control method in a discharge process.

2B. Measurement of filtration tank water level The actual filtration tank water level H1 is measured in another filtering machine during filtration. In addition, what is measured at this time may measure and compare the water level of the overflow part to the treated water outflow channel 6.

2C. In the filtration tank water level comparison flowchart 2C, the actual filtration tank water level H1 and the reference filtration tank water level H1 _STD are compared.
When the actual filtration tank water level H1 is equal to or higher than the reference filtration tank water level H1 _STD , the flow proceeds to the flowchart 2D and the opening degree of the washing water gate 8 is set.
When the actual filtration tank water level H1 is less than the reference filtration tank water level H1 _STD , the flow proceeds to the flowchart 2E and the opening degree of the washing water gate 8 is set.

2D. Since the actual filtration tank water level H1 is equal to or higher than the reference filtration tank water level H1 _{STD in the} cleaning water gate setting flowchart 2C, a sufficient amount of filtered water can be secured. Accordingly, since the cleaning may be performed at the reference cleaning speed, the opening degree of the cleaning water gate 8 is set to a preset reference gate opening degree _GO-STD .
After the opening degree of the cleaning water gate 8 is set to the reference gate opening degree _GO-STD , the process proceeds to the flowchart 2F.

2E. Since the actual filtration tank water level H1 is less than the reference filtration tank water level H1 _{STD in the} washing water gate setting flowchart 2C, the discharge amount of filtrate water decreases, and the washing water becomes insufficient when washing is performed at the reference washing speed. Accordingly, the opening degree of the cleaning water gate 8 is set to a predetermined gate opening degree G _O-SET smaller than the reference gate opening degree G _O-STD to reduce the supply amount of the cleaning water. In order to reduce the amount of filtered water used as the washing water, the washing water in the treated water outflow passage 6 can be continuously supplied without being depleted. The gate opening degree G _O-SET is set so as to vary in proportion to the actual filtration tank water level H1. The gate opening degree G _O-SET may be set to decrease stepwise.
After the opening degree of the washing water gate 8 is set, the process proceeds to the flowchart 2F.

2F. Calculation of the amount of washing wastewater The actual filtration tank water level H2 is measured in the filtration tank 1 during washing. From the actual filtration tank water level H2, an actual cleaning drainage amount QW _-OUT discharged from the cleaning drainage channel 10 is calculated.
Further, the gate opening degree G _O-SET of the washing water gate 8 and the washing water inflow amount Q _W-in flowing into the filtration tank 1 from the actual filtration tank water level H1 are calculated.

The opening degree of the washing water gate 8 is a calculated value calculated based on the actual filtration tank water level H1 of the filtration tank 1 so as to be a predetermined washing water inflow amount. Here, the actual cleaning waste water amount Q _W-OUT is measured, and it is confirmed whether the actual cleaning water inflow amount Q _W-in is equal to the calculated value. If there is an error _{in the} actual cleaning wastewater amount QW _-OUT and the cleaning water inflow amount QW _-in , the opening degree of the cleaning water gate 8 is adjusted in the flowcharts 2G to 2I. Depending on the size of the allowable error, the flowcharts 2G to 2I can be omitted.

2G. Comparison of cleaning wastewater amount The actual cleaning wastewater amount QW _-OUT and the cleaning water inflow amount QW _-in are compared.
When the actual cleaning wastewater amount QW _-OUT is smaller than the cleaning water inflow amount QW _-in , the flow proceeds to the flowchart 2H and the opening degree of the cleaning water gate 8 is set.
When the actual cleaning wastewater amount QW _-OUT is larger than the cleaning water inflow amount QW _-in , the flow proceeds to the flowchart 2I and the opening degree of the cleaning water gate 8 is set.
When the actual cleaning wastewater amount QW _-OUT is equal to the cleaning water inflow amount QW _-in , the process proceeds to the flowchart 2J.

2H. In the cleaning water gate adjustment flowchart 2G, when the actual cleaning drainage amount QW _-OUT is smaller than the cleaning water inflow amount QW _-in , the cleaning water amount is insufficient. In order to increase the actual cleaning wastewater amount QW _-OUT , the opening degree of the cleaning water gate 8 is increased stepwise.
After adjusting the opening degree of the washing water gate 8, the process proceeds to the flowchart 2G.

2I. In the cleaning water gate adjustment flowchart 2G, when the actual cleaning drainage amount QW _-OUT is larger than the cleaning water inflow amount QW _-in , the cleaning water amount is excessive. In order to reduce the actual cleaning drainage amount QW _-OUT , the opening degree of the cleaning water gate 8 is decreased stepwise.
After adjusting the opening degree of the washing water gate 8, the process proceeds to the flowchart 2G.

2J. Accumulated actual cleaning wastewater amount QW _-OUT is integrated to calculate the actual total cleaning wastewater amount ΣQW _-OUT .

2K. Comparison of total cleaning wastewater amount Actual total cleaning wastewater amount ΣQ _W-OUT is compared with reference total cleaning wastewater amount QW _-SET .
When the actual total cleaning waste water amount ΣQ _W-OUT is equal to or larger than the reference total cleaning waste water amount Q _W-SET , the process proceeds to the flowchart 2L to end the cleaning.
When the actual total cleaning drainage amount ΣQ _W-OUT is less than the reference total cleaning drainage amount QW _-SET , the process proceeds to the flowchart 2B and the cleaning is continued.

2L. The washing water gate 8 after washing is closed and filtration is resumed.

The design conditions of the filtration equipment in the embodiment of the present invention are set as follows.
Standard inflow water amount: 3000 m ³ / day, standard filtration tank water level H1 _STD : 2.6 m
Standard filtration rate: 500 m / day, standard opening G _O-STD : 80%
Filtration area: 3000/500 = 6 m ²
Standard total washing wastewater amount Q _W-SET : 6 × 500 × (20 _{min /} 60/24) = 41.7 m ³
Filtration machine: 2 tanks

-When there is much inflow water to a filter The water level of the pressure regulation tank 4 rises during a filtration process, and the filter exceeding a predetermined water level shifts to a draining process, a stirring process, and a drainage process, and performs washing.
In the drainage process, the actual filtration tank water level H1 from the water level of the filtration tank 1 during filtration to the treated water outflow passage 6 is calculated and compared with the reference filtration tank water level H1 _STD . Since a large amount of filtered water is obtained due to a large amount of inflow into the raw water filter, the actual filtration tank water level H1 is higher than the reference filtration tank water level H1 _STD . Therefore, drainage is performed by setting the opening degree of the washing water gate 8 for supplying the washing water to the reference opening degree _GO-STD .

From the actual filtration tank water level H2 measured in the filtration tank 1 being washed, the actual washing drainage amount QW _-OUT discharged from the washing drainage channel 10 is calculated.
Further, the gate opening degree G _O-STD of the washing water gate 8 and the washing water inflow amount Q _W-in flowing into the filtration tank 1 from the actual filtration tank water level H1 are calculated.
The opening amount of the cleaning water gate 8 is finely adjusted in order to compare the cleaning water inflow amount Q _W-in with the actual cleaning waste water amount Q _W-OUT and correct the error of the calculated cleaning water inflow amount Q _W-in . When the actual cleaning wastewater amount QW _-OUT is smaller than the cleaning water inflow amount QW _-in , the opening degree is increased stepwise, and when the actual cleaning wastewater amount QW _-OUT is larger than the cleaning water inflow amount QW _-in , it is opened. Decrease the degree step by step.

Calculates the actual total washing wastewater [sum] Q _W-OUT of the total amount of actual washing wastewater _{Q W-OUT,} compares the actual total washing wastewater [sum] Q _W-OUT and the reference total cleaning wastewater _{Q W-SET.} When the actual total cleaning drainage amount ΣQ _W-OUT reaches the reference total cleaning drainage amount QW _-SET , the process proceeds from the draining process to the filtering process, and the cleaning ends.

Table 1 shows the actual filtration tank water level H1 for each cleaning time, the opening of the cleaning water gate 8, and the actual total cleaning drainage amount ΣQ _W-OUT . The actual filtration tank water level H1 is higher than the reference filtration tank water level H1 _STD and fluctuates with time, but the opening degree of the washing water gate 8 becomes constant at the reference gate opening degree _GO-STD , and the reference total washing drainage amount after 25 minutes. Q _W-SET is satisfied and cleaning is completed.

-When there is little inflow to a filter, the water level of the pressure regulation tank 4 rises during a filtration process, and the filter which exceeded the predetermined water level transfers to a drain process, a stirring process drainage process, and performs washing.
In the drainage process, the actual filtration tank water level H1 from the water level of the filtration tank 1 during filtration to the treated water outflow passage 6 is calculated and compared with the reference filtration tank water level H1 _STD . Since the filtrate water decreases due to a small amount of raw water flowing into the filter, the actual filtration tank water level H1 is lower than the reference filtration tank water level H1 _STD . Accordingly, drainage is performed by setting the opening degree of the cleaning water gate 8 for supplying the cleaning water to a predetermined gate opening degree G _O-SET smaller than the reference opening degree G _O-STD . The gate opening degree G _O-SET is appropriately determined in proportion to the actual filtration tank water level H1. (Or decrease in steps)

From the actual overflow water level H2 measured in the filtration tank 1 being washed, the actual washing drainage amount QW _-OUT discharged from the washing drainage channel 10 is calculated.
Further, the gate opening degree G _O-SET of the washing water gate 8 and the washing water inflow amount Q _W-in flowing into the filtration tank 1 from the actual filtration tank water level H1 are calculated.
The opening amount of the cleaning water gate 8 is finely adjusted in order to compare the cleaning water inflow amount Q _W-in with the actual cleaning waste water amount Q _W-OUT and correct the error of the calculated cleaning water inflow amount Q _W-in . When the actual cleaning wastewater amount QW _-OUT is smaller than the cleaning water inflow amount QW _-in , the opening degree is increased stepwise, and when the actual cleaning wastewater amount QW _-OUT is larger than the cleaning water inflow amount QW _-in , it is opened. Decrease the degree step by step.

Calculates the actual total washing wastewater [sum] Q _W-OUT of the total amount of actual washing wastewater _{Q W-OUT,} compares the actual total washing wastewater [sum] Q _W-OUT and the reference total cleaning wastewater _{Q W-SET.} When the actual total cleaning wastewater amount ΣQ _W-OUT reaches the reference total cleaning wastewater amount QW _-SET , the draining process is terminated.

Table 2 shows the actual filtration tank water level H1, the opening degree of the cleaning water gate 8, and the actual total cleaning waste water amount ΣQ _W-OUT for each cleaning time. Since the actual filtration tank water level H1 is smaller than the reference filtration tank water level H1 _STD , the opening degree of the washing water gate 8 is set to a predetermined gate opening degree G _O-SET smaller than the reference gate opening degree G _O-STD and 35 minutes later. The total cleaning wastewater amount QW _-SET is satisfied and cleaning is completed.

・ When the inflow to the filter fluctuates.
Cleaning is performed by the same cleaning method as in Examples 1 and 2.
Table 3 shows the actual filtration tank water level H1, the opening degree of the cleaning water gate 8, and the actual total cleaning drainage amount ΣQ _W-OUT for each cleaning time. Since the amount of water flowing into the filter is large until 10 minutes after the start of washing, the actual filtration tank water level H1 is higher than the reference filtration tank water level H1 _STD , and the opening degree of the washing water gate is constant at the reference gate opening degree _GO-STD . It is said. However, when 15 minutes have passed since the start of washing, the inflow water to the filter is decreasing. Since the actual filtration tank water level H1 is smaller than the reference filtration tank water level H1 _STD , the gate opening is set to a predetermined gate opening G _O-SET smaller than the reference gate opening G _O-STD . Then, 30 minutes after the start of cleaning, the reference total cleaning drainage amount QW _-SET is satisfied and the cleaning is completed.

  The filtration facility of the present invention saves space because there is no need for a storage tank for storing washing water, and by adjusting the washing water gate from the water level of the filtration tank, washing can be performed in response to fluctuations in the amount of inflow of raw water. Can continue.

DESCRIPTION OF SYMBOLS 1 Filtration tank 3 Filter material layer 6 Processed water outflow channel 8 Washing water gate 10 Washing drainage channel

Claims (3)

A plurality of filters that perform filtration by passing raw water through the filter medium layer (3) formed of a floatable filter medium in parallel , are connected to the plurality of filters, and above the filter tank (1) of the filter In the washing method using the treated water outflow passage (6) for discharging the filtered water more overflowed, and using the filtered water of the other filter as washing water for washing of one filter,
Depending on the water level of the filtered water, which is calculated from the filtered motor above the water level gauge in the other filtration (15),
Determine the opening of the wash water gate (8) that varies the amount of wash water supplied from the bottom of one filter from the treated water outflow passage (6) ,
The opening of the washing water gate (8) is
If the actual filter tank water level of another filtration machine (H1) is based filtration water level _{(H1 STD)} above, the washing water was passed through the washing water gate (8) at the reference gate opening _{(G 0-STD),}
When the actual filtration tank water level (H1) of another filter is less than the reference filtration tank water level (H1 _STD ), the cleaning water gate (8) is set to a predetermined gate opening (G _0-SED ) that is smaller than the reference opening. And
The method of cleaning a filtration device the total amount of washing wastewater from one filtering unit upward and is discharged by flowing Yue and supplying continuously the washing water reaches a predetermined amount. Each filter has a wash drain (10) that drains wash sewage,
Calculate the overflow water level from the actual filtration tank water level (H2) of the one filter to the washing drainage channel (10) to calculate the actual washing drainage amount (QW _-OUT ) of the washing sewage,
The cleaning method for a filter according to claim 1, wherein the actual total amount of cleaning waste water (ΣQ _W−OUT ) is calculated by integrating the actual amount of cleaning waste water (Q _W−OUT ). Wash water inflow amount (Q _W-in ) calculated from the actual filtration tank water level (H1) of the other filter and the opening of the wash water gate (8),
Compare the actual washing drainage amount (Q _W-OUT ) calculated from the actual filtration tank water level (H2) of the one filter,
If the actual wash drainage (Q _W-OUT ) is greater than or equal to the wash water inflow (Q _W-in ), reduce the opening of the wash water gate (8) step by step,
If the actual washing wastewater (Q _W-OUT) is smaller than the washing water inflow (Q _W-in), as set forth in claim 2, characterized in that to increase the opening degree of the washing water gate (8) stepwise How to wash the filter.

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