JP5779001B2 - Sewage inflow calculation method and sewage inflow calculation device - Google Patents

Description

  The present invention relates to a sewage inflow calculation method and a sewage inflow calculation device for calculating the inflow of sewage into a pump well.

  In general, water treatment plant equipment (hereinafter abbreviated as plant equipment) is configured to flow into a pump well through a sand basin, so that the amount of sewage flowing into the pump well (hereinafter abbreviated as sewage inflow). ) Is difficult to measure accurately. For this reason, when simulating the behavior of plant equipment using the sewage inflow amount or investigating the tendency of the sewage inflow amount, it is necessary to calculate the sewage inflow amount by calculation. From such a background, a system for calculating a sewage inflow amount by calculation has been proposed (see Patent Document 1).

Japanese Patent Laid-Open No. 11-272336

  However, the system described in Patent Document 1 is configured to calculate the amount of sewage inflow based on the amount of sewage pumped from the pump well and the amount of change in the level of sewage in the pump well. For this reason, according to the system described in Patent Document 1, when the amount of pumped sewage changes greatly, such as when the number of pumps that pump sewage changes, between the change in the amount of pumped sewage and the change in the water level. Therefore, the amount of sewage inflow cannot be accurately calculated.

  The present invention has been made in view of the above problems, and the object thereof is a sewage inflow amount calculation method and sewage that can accurately calculate the sewage inflow amount even when the pumped amount of sewage has changed greatly. It is to provide an inflow amount calculation device.

In order to solve the above-mentioned problems and achieve the object, the method for calculating the amount of sewage inflow according to the present invention is a method for calculating the amount of sewage inflow that calculates the amount of inflow of sewage into the pump well, Using a function that shows the change in the amount of inflow of sewage per predetermined time, which is derived from the integrated value of the amount of pumped water, assuming that the amount of sewage pumped and the amount of inflow of sewage correspond one-to-one. The amount of sewage inflow at an arbitrary time is calculated using the step of calculating the amount of inflow of sewage at an arbitrary time as the first inflow of sewage and the amount of pumped sewage at an arbitrary time and the water level of the pump well . calculating a 2 sewage inflow, characterized in that it comprises calculating a weighted sum of the first sewage inflow amount and the second sewage inflow as inflow of sewage at any time, the.

In order to solve the above-described problems and achieve the object, a sewage inflow amount calculating device according to the present invention is a sewage inflow amount calculating device that calculates an inflow amount of sewage into a pump well, Using a function that indicates the change in the amount of inflow of sewage per predetermined time, which is derived from the integrated value of the amount of pumped water, assuming that the amount of inflow of sewage and the amount of sewage pumped in one-to-one correspondence. The amount of sewage inflow at an arbitrary time is calculated using the means for calculating the inflow of sewage at an arbitrary time as the first inflow of sewage, and the amount of sewage pumped at the arbitrary time and the water level of the pump well . It means for calculating a sewage inflow, characterized in that it comprises means for calculating a weighted sum of the first sewage inflow amount and the second sewage inflow as inflow of sewage at any time, the.

  According to the sewage inflow amount calculation method and the sewage inflow amount calculation device according to the present invention, the sewage inflow amount can be accurately calculated even when the pumped amount of sewage is greatly changed.

FIG. 1 is a schematic diagram showing a configuration of a water treatment plant facility to which a sewage inflow amount calculating apparatus according to an embodiment of the present invention is applied. FIG. 2 is a flowchart showing a flow of sewage inflow amount calculation processing according to an embodiment of the present invention. FIG. 3 is a diagram for explaining a method of calculating the sewage inflow amount from the integrated value of the sewage pumping amount. FIG. 4 is a diagram for explaining a method of calculating the sewage inflow amount from the integrated value of the sewage pumping amount.

  Hereinafter, the configuration and operation (sewage inflow amount calculation method) of a sewage inflow amount calculation apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[Configuration of water treatment plant equipment]
First, with reference to FIG. 1, the structure of the water treatment plant equipment to which the sewage inflow amount calculation apparatus which is one Embodiment of this invention is applied is demonstrated.

  FIG. 1 is a schematic diagram showing a configuration of a water treatment plant facility to which a sewage inflow amount calculating device according to an embodiment of the present invention is applied. As shown in FIG. 1, a water treatment plant facility 1 to which a sewage inflow amount calculating device according to an embodiment of the present invention is applied, pumps sewage 4 flowing into a pump well 3 from a sand basin 2 into a discharge well 5. The water absorption pump 6 is provided. The sewage 4 pumped to the discharge tank 5 is supplied to a water treatment facility 7 including an initial settling tank, an aeration tank, a final settling tank, and the like for processing.

The water treatment plant facility 1 includes a water level sensor 8, a sewage pumping amount sensor 9, and a control device 10 as a control system. The water level sensor 8 detects the water level L of the sewage 4 in the pump well 3 and inputs an electrical signal indicating the detected water level L to the control device 10. Sewage pumping amount sensor 9, the flow rate of sewage 4 is pumped to the discharge culvert 5 by intake pump 6 detected as sewage pumping amount Q _0, inputs the electric signal indicating a sewage pumping amount Q ₀ which is detected in the control unit 10 To do.

The control device 10 is configured by an arithmetic processing device such as a workstation or a personal computer. The control device 10 calculates an inflow amount Q _i of the sewage 4 to the water treatment plant facility 1 at an arbitrary time t (hereinafter abbreviated as sewage inflow amount Q _i ) by executing a sewage inflow amount calculation process described later. By controlling the function and the number of rotations of the water absorption pump 6 and the opening degree of the on-off valve 11 provided between the discharge tank 5 and the water absorption pump 6, the water level L of the sewage 4 in the pump well 3 is kept within a predetermined range. And a function to control.

[Calculation method of sewage inflow]
In the water treatment plant facility 1 having such a configuration, the control device 10 calculates the sewage inflow amount Q _i at an arbitrary time t by executing the sewage inflow amount calculation process described below. Hereinafter, with reference to the flowchart shown in FIG. 2, operation | movement of the control apparatus 10 at the time of performing wastewater inflow amount calculation processing is demonstrated.

  FIG. 2 is a flowchart showing a flow of sewage inflow amount calculation processing according to an embodiment of the present invention. The flowchart shown in FIG. 2 starts when the operator instructs the control device 10 to start the sewage inflow amount calculation process, and the sewage inflow amount calculation process proceeds to step S1.

In the process of step S1, the control unit 10 calculates the sewage inflow Q _i at any time t by using the data of the sewage pumping amount Q ₀ of every predetermined time (for example, daily data). Specifically, as shown in FIG. 3, the control device 10 sets the sewage pumping amount Q ₀ every predetermined time (in this example, every hour) based on the electric signal input from the sewage pumping amount sensor 9. Accumulated values h _{1 to} h ₂₄ are stored. Therefore, the control device 10, assuming that the sewage inflow Q _i and sewage pumping amount Q ₀ is a one-to-one correspondence, a linear function y = a n _{x +} b representing the change in the sewage inflow Q _i at each time period _n is derived. Here, parameters x and y in the linear function indicate time and sewage inflow amount Q _i , respectively, and parameters a _n and b _n indicate coefficients determined for each time zone n.

For example, as shown in FIG. 4A, in the time zone from 0 o'clock to 1 o'clock (n = 1), the control device 10 performs a linear function y indicating a change in the sewage inflow amount Q _{i from} 0 o'clock to 1 o'clock. = assuming integral values of _a 1 x + _{b 1} coincides with the accumulated value _{h 1} of 0:00 to 1:00 sewage pumping amount _{Q 0,} to calculate the linear function _y = a 1 coefficients _a 1 in x + _{b 1, b 1} . The time zone to 2 o'clock 1 as shown in FIG. 4 (b) in (n = 2), the control unit 10, a primary showing a change in 1:00 1.5 o'clock sewage inflow _{Q i} The sum of the integral value of the function y = a ₁ x + b _{1 and} the integral value of the linear function y = a ₂ x + b ₂ indicating the change in the sewage inflow amount Q _i between 1.5 o'clock and 2 o'clock is between 1 o'clock and 2 o'clock. assuming matching the accumulated value _{h 2} of the sewage pumping amount _{Q 0,} to calculate the linear function _y = a 2 x + _b coefficients _{2 a 2, b 2.}

That is, the control device 10 applies the following mathematical formulas (1) and (2) to the determinant (3) shown below, and thereby the linear function y indicating the change in the sewage inflow amount Q _i in each time zone n. = _An x + b _n is derived. The following mathematical formula (2) is connected to the linear function y = a _{n + 1} x + b _{n + 1} in the time zone n + 1 at the intermediate position of the time zone n + 1 where the linear function y = a _n x + b _n in the time zone n is adjacent. The boundary conditions for are shown. By deriving the linear function y = a _{n x +} b n indicating the change of the sewage inflow Q _i at each time period n, the control device 10 can calculate the sewage inflow Q _i at any time t. Thereby, the process of step S1 is completed and the sewage inflow amount calculation process proceeds to the process of step S2.

In the process of step S2, the control unit 10 calculates the sewage inflow Q _i at any time t by using the instantaneous value of the wastewater pumping amount Q ₀ which has been detected by the sewage pumping amount sensor 9. Specifically, the control device 10 uses the sewage pumping amount Q ₀ detected by the sewage pumping amount sensor 9, the time change amount dL / dt of the water level L of the sewage 4 detected by the water level sensor 8, and the water level sensor 8. By substituting the cross-sectional area S (L) of the pump well 3 at the detected water level L of the sewage 4 into the following formula (4), the sewage inflow amount Q _i at an arbitrary time t is calculated.

In addition, table data indicating the relationship between the water level L of the sewage 4 and the cross-sectional area S (L) of the pump well 3 is stored in the control device 10 in advance, and the control device 10 refers to this table data to store the sewage. The cross-sectional area S (L) of the pump well 3 at the water level L of 4 is specified. Further, the control device 10 uses the average value of the instantaneous values before and after an arbitrary time t, that is, by calculating the sewage inflow amount Q _i by smoothing the instantaneous value, the amount of sewage pumped up significantly changed. Even in such a case, it is preferable that the inflow amount of sewage can be accurately calculated. Thereby, the process of step S2 is completed and the sewage inflow amount calculation process proceeds to the process of step S3.

In the process of step S3, the control unit 10 calculates the weighted sum of the sewage inflow Q _i calculated by Sewage inflow Q _i and step S2 calculated by the processing in step S1, the calculated weighted The sum value is defined as an inflow amount Q _i of the sewage 4 to the water treatment plant facility 1. Specifically, the control device 10 sets the sewage inflow amount Q _i calculated by the process of step S1 as the sewage inflow amount Q _i1 , and the sewage inflow amount Q _i calculated by the process of step S2 as the sewage inflow amount Q _i2. , sewage inflow Q _{i 1} in equation (5) shown _below, and by substituting the sewage inflow Q _i2, calculates the sewage inflow Q _i at any time t. Here, the parameter r in the mathematical formula (5) is a value of 0 or more and 1 or less, and is a value that can be appropriately set by the operator. Thereby, the process of step S3 is completed and a series of sewage inflow amount calculation processes are complete | finished.

As apparent from the above description, an embodiment in a is sewage inflow quantity arithmetic form, the control apparatus 10, the predetermined time that is derived by utilizing the integrated value of the wastewater pumping amount Q ₀ of every predetermined time of the present invention The sewage inflow amount Q _i1 at an arbitrary time t is calculated using a linear function indicating the change in the sewage inflow amount Q _i for each time, and the sewage pumping amount Q ₀ and the water level L of the sewage 4 at an arbitrary time t are calculated. Since the sewage inflow amount Q _i2 at an arbitrary time t is calculated and the weighted sum of the calculated sewage inflow amount Q _i1 and the sewage inflow amount Q _i2 is calculated as the sewage inflow amount Q _i at an arbitrary time t. Even if the pumping amount of the sewage 4 changes greatly, the sewage inflow amount Q _i can be accurately calculated.

  Although the embodiment to which the invention made by the present inventor is applied has been described above, the present invention is not limited by the description and the drawings that form a part of the disclosure of the present invention according to this embodiment. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Water treatment plant equipment 2 Sedimentation basin 3 Pump well 4 Sewage 5 Discharge tank 6 Water absorption pump 7 Water treatment equipment 8 Water level sensor 9 Sewage pumping amount sensor 10 Control device

Claims (2)

A method for calculating the amount of inflow of sewage into a pump well,
From the integrated value of the amount of sewage discharged every predetermined time, the amount of sewage inflow per predetermined time derived on the assumption that the amount of pumped sewage and the amount of inflow of sewage correspond one-to-one. Calculating a sewage inflow amount at an arbitrary time as a first sewage inflow amount using a function indicating change;
Calculating the amount of inflow of sewage at an arbitrary time as a second amount of inflow of sewage using the pumped amount of sewage at an arbitrary time and the water level of the pump well ;
Calculating a weighted sum of the first sewage inflow amount and the second sewage inflow amount as the sewage inflow amount at an arbitrary time;
A method for calculating the amount of inflow of sewage, comprising: A sewage inflow calculation device for calculating an inflow of sewage into a pump well,
From the integrated value of the amount of sewage pumped at each predetermined time, the amount of sewage inflow for each predetermined time derived on the assumption that the amount of sewage inflow and the amount of sewage pumped correspond one-to-one. Means for calculating an inflow amount of sewage at an arbitrary time as a first inflow amount of sewage using a function indicating change;
Means for calculating the inflow amount of sewage at an arbitrary time as the second inflow amount of sewage using the pumped amount of sewage at an arbitrary time and the water level of the pump well ;
Means for calculating a weighted sum of the first sewage inflow amount and the second sewage inflow amount as an inflow amount of sewage at an arbitrary time;
A sewage inflow amount calculating device comprising:

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