JP2018018413A - Sewage unknown water simple evaluation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage unknown water simple evaluation method that contributes to understanding of the actual state of a wide-ranging unknown water problem by enabling unknown water to be evaluated at low cost.SOLUTION: Provided is a sewage unknown water simple evaluation method that calculates the water level of sewage on the basis of a measurement value of a first pressure gauge installed in a sewage pipeline facility so as to measure pressure corresponding to the water-level of the sewage and a measurement value of a second pressure gauge installed in a place opened to the atmosphere so as to measure atmospheric pressure applied on the water surface of the sewage, and evaluates the unknown water on the basis of the calculated water level. The evaluation is executed by carrying out measurements by the first and second pressure gauges for each prescribed time, generating date data by dividing the water level of each measurement time based on the obtained measurement values by dates, and diving the date data into data obtained on a target rainy day when a precipitation amount per day is equal to or lager than a fixed amount, and data obtained on rainfall influence days within a predetermined number of days from the target rainy day, data obtained on fine days which are not rainfall influence days, and data other than these.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a simple evaluation method of unknown sewage water that can be used for investigation of unknown water in a sewage pipeline facility, for example.

  There is an unknown water problem as an important issue in the maintenance of sewage pipeline facilities. Unknown water means the difference between the amount of sewage flowing into the sewage treatment plant and the amount of water supply (water supply). Unidentified water mainly includes rainwater intrusion water (direct infiltration water) that flows directly into the sewer pipe facility during rainy weather, rainwater intrusion water (penetration infiltration water) that enters the sewer pipe facility after the rain penetrates the ground, It consists of groundwater, irrigation water, and constantly intruded water into which seawater flows. In general, the sewerage usage fee is calculated from the water supply usage fee, but if there is a lot of unknown water, not only will the processing costs exceed the plan, but there will be contamination of public water areas due to overloading of the treatment plant, Unknown water has become a very serious problem in terms of sewage maintenance and management, such as hollowing around the pipeline, sinking the road, and shortening the life of the pipeline facility itself.

  However, at present, the actual situation of unknown water problems on a nationwide scale has not been grasped at all, and a screening survey (surface) necessary for sewerage infrastructure stock management (lifetime management and risk management) is the beginning of this understanding. The technology that enables the development of a simple survey has not yet been realized.

  The present invention has been made in consideration of the above-mentioned matters, and the purpose thereof is to provide a simple evaluation method for unknown water that enables evaluation of unknown water at a low cost and contributes to grasping the actual situation of a wide range of unknown water problems. There is to do.

  In order to achieve the above-mentioned object, the simplified evaluation method of unknown sewage water according to the present invention includes a measurement value of a first pressure gauge installed in a sewage pipeline facility to measure a pressure corresponding to a sewage water level. The water level of the sewage is determined based on the measured value of the second pressure gauge installed at a location open to the atmosphere to measure the atmospheric pressure acting on the water surface of the sewage, and the obtained water level It is a simple evaluation method of unknown sewage water that evaluates unknown water on the basis of each of the pressure gauges measuring at a predetermined time, and dividing the water level at each measurement time based on the obtained measurement value by date to obtain date data The date data is obtained on the target rainy day when the daily precipitation is above a certain level, the data obtained on the rainy effect day within the specified number of days from the target rainy day, and the rainy effect date is not applicable. It was divided into those obtained on a clear day and those other than these. In performing the evaluation (claim 1).

  In the simple evaluation method of the sewage unknown water, excluding the date data that has a missing part, and for the date data obtained on the clear day, the part where the water level changed suddenly over time and The evaluation may be performed by excluding a part that does not change over a predetermined time (Claim 2).

  In the above simple evaluation method of unknown sewage water, continued using measurement data temporarily measured by the flowmeter or velocimeter at the sewage pipeline facility, the water level obtained continuously, and Manning's formula Flow rate data may be obtained (claim 3).

  In the simple evaluation method of sewage unknown water, the first pressure gauge has a temperature measurement function, or provided with a temperature measurement means for measuring the temperature of the sewage, and the measured value of the obtained sewage temperature and the You may evaluate the flow volume of always intrusion water based on flow volume data (Claim 4).

  In the present invention, it is possible to evaluate unknown water at a low cost, and a simple evaluation method for unknown sewage water that contributes to grasping the actual situation of unknown water problems over a wide range is obtained.

  That is, in the simple evaluation method of sewage unknown water according to the claims of the present application, since an inexpensive pressure gauge can be used, the unknown water can be evaluated at low cost, and since it is low cost, it is unknown over a wide range. It can also be used to understand the actual situation of water problems.

  In the simple evaluation method of sewage unknown water according to the second aspect of the invention, the evaluation can be simplified and the accuracy can be improved.

  In the simple evaluation method of sewage unknown water according to the third aspect of the invention, quantitative evaluation based on simple calculation of the sewage flow rate is possible.

  In the simple evaluation method of sewage unknown water according to the invention of claim 4, it is possible to perform simple quantitative determination of always intruded water, determination of the presence or absence of business wastewater, and the like.

It is explanatory drawing which shows roughly the structure of the simple evaluation method of sewage unknown water which concerns on one embodiment of this invention, and has expanded and illustrated one part. It is explanatory drawing which shows the method for calculating | requiring the flow product A, the wet edge S, and the diameter depth R from the radius r and the water level h of a sewer pipe. (A) is a chart showing the water level and the amount of rainfall at each time obtained by the simple evaluation method of unknown sewage water, and (B) is a chart including a disconnection pattern and an unchanged pattern.

  Embodiments of the present invention will be described below with reference to the drawings.

  The simple evaluation method for unknown sewage water according to the present embodiment is a method for evaluating unknown water in a sewage pipeline facility, in order to measure the pressure corresponding to the water level in the sewage pipeline facility. A first pressure gauge (water level gauge) 1 installed at each of a plurality of locations A (1) to A (N) (for example, 100 locations) of the facility is used (see FIG. 1).

  The first pressure gauge 1 of the present embodiment can be installed (temporary) in a sewage pipe facility in a short time by a dedicated mount, and has a data logger (with a recording meter and an integrating meter) and an absolute pressure detection type water level. A sensor can be used. Such a water level sensor is available at a low price of, for example, about 50,000 yen. Normally, such a water level sensor is provided with a temperature sensor for pressure compensation.

In addition, since the measurement accuracy of the water level is not guaranteed only by the absolute pressure (water pressure) obtained by the first pressure gauge 1, in this embodiment, the atmospheric pressure acting on the water surface of the sewage flowing through the sewage pipeline facility is measured. For this purpose, a second pressure gauge (atmospheric pressure logger) 2 installed at a location open to the atmosphere is also used (see FIG. 1). As the second pressure gauge 2, the same one as the first pressure gauge 1 can be used. However, when the first pressure gauge 1 is installed at a plurality of locations A (1) to A (N), the second pressure gauge 2 is necessarily installed to correspond to the first pressure gauge 1 on a one-to-one basis. There is no need, and if it is in the area B (B _{1 to} B _n ) where the atmospheric pressure can be identified, even if a plurality of first pressure gauges 1 are provided in the area B, the second pressure gauge 2 is at least You only need to install one. In FIG. 1, only the areas B ₁ and B _n are shown enlarged.

  And the measured value obtained with each pressure gauge 1 and 2 is sent to information equipment (information terminal) outside a figure, for example, and based on the difference (differential pressure) of the absolute pressure obtained with both pressure gauges 1 and 2 The sewage water level is calculated, and unknown water is evaluated based on this water level. This evaluation method will be described in detail below.

  First, each of the pressure gauges 1 and 2 performs measurement every predetermined time (for example, 1 to 5 minutes), and the water level (collected data) at each measurement time based on both measurement values continuously obtained in the information equipment is the date ( For example, date data (primary processed data) is divided by midnight to midnight. In addition, what is necessary is just to adjust suitably the time interval which each pressure gauge 1, 2 measures according to the change degree of a measured value. In this example, the date data includes, for example, not only the water level at each measurement time but also the time value (average value of the water level every hour), the maximum value of the time value of each day (maximum time water level), the minimum When a value (time minimum water level), an average value (time average value), and the pressure gauges 1 and 2 measure every minute, a 5-minute average value (for charts) and the like are included.

  Then, unknown sewage water is evaluated based on a plurality of date data. However, since the water level of sewage is affected by rainfall (including snowfall), in this embodiment, the daily precipitation is constant. (Preliminary reference value, for example, 10 mm) The rainy day data obtained on the target rainy day or more and the rainy effect day that is a clear day within a predetermined number of days from the target rainy day (for example, only the day after the target rainy day) , Or the next day and the day after the next day, etc.), clear day data obtained on a clear day that does not fall on a rainy influence day, and other excluded days (for example, rainy days but daily precipitation) Are obtained on the day less than the reference value), and the date data of the exclusion date is excluded from the evaluation target (analysis target), and then the evaluation is performed for each classification date.

  Here, the rainy day is divided into the target rain day and the excluded rain day by extracting the days with significant rainfall effects as the target rain days and not extracting the days with no significant rain effects. This is for improvement. The reason for extracting rain-affected days is to evaluate the infiltration water.

  In addition, among the date data, date data having a missing part in 24 hours is excluded from the evaluation target (in the example of FIG. 3A, data of 8/25 (Tuesday), 9/28 (Month). ). Furthermore, for date data obtained on a clear day, a portion where the water level has changed abruptly over time (portion forming a break pattern X as shown in FIG. 3B) and a predetermined time (for example, 10 minutes to 1 hour) Those having a portion that does not change over the above (portion that forms the unchanged pattern Y as shown in FIG. 3B) are excluded from the evaluation target. The determination of the presence / absence of the disconnection pattern X may be performed based on, for example, setting a range of change or rate of change in the water level that is allowed for each time and whether or not it is within the set range.

  In the present embodiment, the date data obtained in a predetermined period (for example, 4 weeks or more) over a plurality of days at each location A is divided into rainy day data, influence date data, and clear day data as described above. The maximum value (maximum period water level), minimum value (minimum period water level), average value (period average water level), etc. of the time value during a predetermined period (for example, 4 weeks or more) are obtained. In consideration of the tube diameter, it is automatically evaluated by the following evaluation method.

  That is, first, in the sewer pipe, the sewage water level tends to rise during rainy weather, and if the maximum sewage water level during rainy weather is within the range that can be afforded from the pipe diameter of the sewer pipe, There is little need for detailed evaluation of unknown water flowing through sewer pipes. Therefore, first, it is determined whether or not the unknown water needs to be evaluated. Specifically, the period maximum water level on the rain target day (or the maximum period water level only for the rain target day with a specific daily precipitation such as 50 mm) corresponds to a margin rate (for example, 20%) from the pipe diameter of the sewer pipe. Based on whether or not it exceeds the water level obtained by subtracting the minute, if it does not exceed, it is judged that the evaluation of unknown water is unnecessary, and only the water exceeding it is evaluated.

  Of the unknown water, the directly influent water is, for example, the maximum water level of the rainy day data (or date data obtained only on the rainy target day of a specific daily precipitation such as 30 mm) with respect to the average water level of the sunny day data. The degree can be evaluated by the ratio of the average water level during the period.

  Among the unknown water, the infiltration intrusion water is, for example, the period average water level of the influence date data on the period average water level of clear day data (or date data obtained only on the rain target day of a specific daily precipitation such as 30 mm) and / or Alternatively, the amount can be evaluated by the ratio of the period maximum water level.

  Of the unknown water, the amount of constantly intruded water can be evaluated, for example, by the minimum water level for the period of sunny day data.

  According to the simple evaluation method of sewage of this embodiment performed as described above, it is possible to evaluate unknown water at a low cost, and it is possible to contribute to grasping the actual state of a wide range of unknown water problems.

  In addition, this invention is not limited to said embodiment at all, Of course, it can change and implement variously in the range which does not deviate from the summary of this invention. For example, the following modifications can be given.

  The above embodiment enables simple, relative and qualitative automatic evaluation of sewage by utilizing the correlation and similarity between the sewage water level and the flow rate, and is based on the segregated and separated sewage water level. Is used to improve the speed and economy and facilitate the development of screening surveys necessary for sewer infrastructure stock management, but it can also be applied to quantitative evaluation based on simple calculation of sewage flow rate. is there.

  Specifically, the measurement data temporarily measured in the sewage pipeline facility by the flow meter 3 (see FIG. 1) or the velocimeter, and the water level (measured value) obtained continuously by the pressure gauges 1 and 2 By using the Manning formula (average flow rate formula), for example, in the information device, continuous flow rate data can be easily obtained, and quantitative evaluation of sewage can be performed using this flow rate data.

That is, first, Manning's average flow rate formula is
V _m = (1 / n) · R ^2/3 · I ^1/2 (1)
It is represented by
here,
V _m : Average flow velocity (m / sec)
n: Manning roughness coefficient R: Diameter depth (m)
I: gradient.

The diameter depth R (m) in the equation (1) is obtained by dividing the flow product A (m ² ) by the wet side (length in which the flow contacts the transverse wall surface) S (m). That is,
R = A / S (2)

The flow rate Q is
Q = A · V _m (3)
Obtained by.

The above formula (1) can be applied to the flow rate of sewage flowing through the sewage pipeline, and at this time, (1 / n) · I ^1/2 on the right side of the formula (1) is regarded as a constant specific to the sewage pipeline. It can be said that the average flow velocity V _m is a function of the diameter depth R. Further, in the case of a sewage pipe having a circular cross-sectional shape, the flow A, the wetted edge S, and the diameter depth R can be obtained from the water level of the sewage flowing through the sewage pipe (this method will be described later). . Accordingly, the measured average flow velocity V _m (this average flow velocity V _m may be directly measured by the flow meter 3 or the flow meter, or obtained by substituting the flow rate Q measured by the flow meter 3 into the above equation (3). And the above constant (1 / n) · I ^1/2 is obtained by substituting into the formula (1) the diameter depth R derived from the sewage water level calculated from the pressure gauges 1 and ² . Thereafter, by substituting the value of the diameter depth R calculated from the water level of the sewage into the equation (1), the average flow velocity V _{m and} further the flow rate Q can be obtained simply and approximately. Therefore, continuous flow rate data can be obtained simply by continuously measuring the sewage water level. Strictly speaking, if the diameter depth R (sewage water level) changes in the equation (1), the roughness coefficient n also changes. However, the amount of change is limited, and the flow rate Q is simply evaluated. It will not be a serious problem in the scene.

Here, as the flow meter 3, an ultrasonic surface velocity type flow meter (for example, manufactured by PENTAF Corporation or Mainstream Corporation) frequently used in the flow measurement of sewers can be used. This surface velocity type flow meter calculates the flow rate from the average flow velocity measured by the Doppler velocimeter and the flowing water cross section obtained from the water level measurement, but is generally expensive (about 2 to 2.4 million yen). Thus, the average flow velocity V _m can be measured. Then, instead of installing a plurality of expensive surface velocity type flow meters 3 at a plurality of locations (fixed installation), for example, one surface velocity type flow meter 3 is carried around and temporarily (for example, once) Only) By measuring the average flow velocity V _m or the flow rate Q, the evaluation can be performed at low cost. At this time, the first pressure gauge (water level sensor) 1 is attached to each of the locations A (1) to A (N) at the same time when the surface velocity type flow meter 3 is carried to the locations A (1) to A (N). You may make it install. As the flow meter 3, an expensive flume flow meter may be used as in the surface velocity type flow meter. In this case, measurement data can be obtained by a water level meter, and the flow rate or flow velocity can be obtained by the flow meter 3. Instead of measuring, the flow velocity may be measured by an anemometer.

  Further, as shown in FIG. 2, when the water level of the sewage flowing through the sewage pipe having a circular cross section having a radius r is h, the flow product A, the plume S and by extension from the water level h as follows: The diameter depth R can be obtained.

  First, in FIG. 2, point o is the center of the cross section of the pipe, points a and b are the contact points between the sewage water surface and the pipe wall inner surface, and point c is a vertical line passing through the point o. The point d is the point of contact between the vertical line passing through the point o and the inner surface of the tube wall and the lowest point on the inner surface of the tube wall. At this time, the water level h is represented by the length of the straight line cd.

In FIG. 2, the wet side P is represented by the length of the arc ab. Therefore, when the circumferential angle (= ∠aob) corresponding to the arc ab is θ (rad),
P = rθ (4)
It becomes.

On the other hand, in FIG. 2, the flow product A is an area of a portion surrounded by the arc ab and the straight line ab, and is equal to the area of the fan oab minus the area of the triangle oab. That is, the product A is
A = (area of fan oab) − (area of triangle oab)
= Πr ² × (θ / (2π))
− (1/2) × [2 × r × sin (θ / 2) × r × cos (θ / 2)]
= R ² × θ / 2−r ² × sin (θ / 2) × cos (θ / 2)
= R ² × θ / 2−r ² × ((1/2) × (sin (θ) + sin (0))
= (1/2) × r ² × (θ−sin (θ) −sin (0))
= (1/2) × r ² × (θ−sin (θ)) (5)
It becomes.

Substituting Equations (4) and (5) into Equation (2),
R = A / S
= (1/2) × r ² × (θ−sin (θ)) / (rθ)
= R × (θ−sin (θ)) / (2θ) (6)
It becomes.

As shown in the equations (4), (5), and (6), the flow product A, the wetted edge S, and the diameter depth R can be obtained from the radius r and the circumferential angle θ. Of these, the radius r is a known value, and the circumferential angle θ is determined by the radius r and the water level h. That is,
h = straight line cd
= Line od-Line oc
= R-r * cos (θ / 2)
And transforming this equation,
cos (θ / 2) = 1− (h / r)
It becomes. Therefore, by using the radius r, which is a known value, and the water level h obtained by the pressure gauges 1 and 2, the circumferential angle θ and consequently the flow product A, the wetness S and the diameter depth R can be obtained.

  For example, in an area where normal infiltration water flowing into the sewage pipe is expected to be relatively large, the above-mentioned flow rate data obtained using the Manning formula, sewage temperature measurement results, expected sewage temperature and normal infiltration water By using the temperature and calculating the ratio of the constantly intruding water contained in the sewage, it is possible to simply determine the constantly invading water flowing through the sewage pipe.

That is, first, the amount of sewage obtained using Manning's formula is Q ₀ , the measured sewage temperature is T ₀ , the amount of sewage is Q _s , and the sewage temperature assumed as a typical average value (for example, 25 ° C.) is T _s, constantly entering water Q _w, typical assumed as the average value is constantly entering water temperature (for example 18 ° C.) and T _w.

The amount of sewage Q ₀ is considered to be the sum of the amount of sewage Q _s and the amount of constant infiltration water Q _w
Q ₀ = Q _s + Q _w
And transforming this equation,
Q _s = Q ₀ -Q _w (7)
It becomes.

In addition, since the amount of heat (heat load amount) of sewage is considered to be the sum of the amount of heat of sewage and the amount of heat of constantly intruded water,
_{Q 0 T 0 = Q s T} s + Q w T w ... (8)
It is.

Substituting and transforming equation (7) into equation (8),
Q ₀ T ₀ = (Q ₀ -Q _w ) T _s + Q _w T _{w
Q 0 T 0 = Q 0 T} s -Q w T s + Q w T w
_{Q w T s -Q w T w} = Q 0 T s -Q 0 T 0
Q _w (T _s −T _w ) = Q ₀ (T _s −T ₀ )
Q _w = Q ₀ (T _s −T ₀ ) / (T _s −T _w )
Thus, a constant intrusion water amount _Qw is obtained. However, when the _{T w} ≧ _{T 0,} the _Q w = Q _0. In general, the temperature T _w of constantly entering water does not change almost 1 year, sewage temperature T _s in order to vary with the seasons, etc., for example it may be different sewage temperature T _s to be used for each period of seasons such as .

  Here, the measurement of the sewage temperature can be performed using the temperature measurement function (temperature sensor) that the first pressure gauge 1 normally has, but a temperature measurement means is separately provided for the measurement of the sewage temperature. It may be provided.

  As a further application example, when the temperature difference between business wastewater and general sewage can be used, the presence or absence of business wastewater and the amount of business wastewater can be determined by installing, for example, the first pressure sensor 1 with a temperature sensor at the business wastewater destination. Can be confirmed and quantified.

  Further, in addition to the determination of the constantly inflowing water amount, for example, a groundwater level measuring device is provided in the sewage manhole, and by using the measurement result of the groundwater level, it is possible to perform a correlation analysis between the contour line of the groundwater level and the inflowing water amount.

  The evaluation of the pipe diameter ratio (that is, the full pipe margin ratio) of the highest water level performed in the above embodiment can be used as it is for the evaluation of rainwater management (inundation countermeasures).

  Sewage heat is used to save energy in the heat load of sewage, which is expected to have a stable temperature and flow rate throughout the year. The water flow medium pipe, hot / cold air blower, and heat pump are used as heat exchangers around the sewage pipe. Etc. are used. And by reflecting the actual measurement values of the sewage amount and the sewage temperature in this design, it is expected to improve the accuracy of sewage heat utilization, and the simple evaluation method of sewage in the above embodiment can be applied. .

  In the combined sewer system, the water level observation can be easily performed by carrying out the simple evaluation method of the sewage in the above embodiment on the upstream side of the diversion basin overflow weir. The accuracy is not expected due to the wide crest and slant or crossover, but it is possible to calculate the flow rate easily from the overflow depth, and it can be used to measure the amount of rainfall and the relationship between rainfall intensity and the start of overflow. .

  The highest clear water level in the above-mentioned embodiment and the result of simple calculation of sewage amount combined with the above-mentioned flow velocity measurement and Manning formula are used for environmental investigation of pipe correction work, construction availability and selection of water change pump can do.

  Needless to say, the above modifications may be combined as appropriate.

1 1st pressure gauge 2 2nd pressure gauge 3 Flowmeter A Multiple locations of sewage pipeline facilities B area

Claims (4)

In order to measure the pressure corresponding to the water level of the sewage, the first pressure gauge installed in the sewage pipe facility and the atmospheric pressure acting on the water surface of the sewage are opened to the atmosphere. It is a simple evaluation method of sewage unknown water that determines the water level of the sewage based on the measured value of the second pressure gauge installed at the location, and evaluates the unknown water based on the determined water level,
Each of the pressure gauges measures at a predetermined time, and the water level at each measurement time based on the obtained measurement value is divided into dates to obtain date data. It is classified into those obtained, those obtained on rainy-affected days within a specified number of days from the target rainy day, those obtained on a clear day that does not correspond to the rain-affected days, and those other than these. The simple evaluation method of the sewage unknown water characterized by performing said evaluation by.   Of the date data, those with missing parts are excluded, and the date data obtained on the clear day has parts where the water level has changed suddenly over time and parts that have not changed over a predetermined time. The simple evaluation method of sewage unknown water according to claim 1, wherein the evaluation is performed by removing the sewage.   The continuous flow rate data is obtained by using the measurement data temporarily measured in the sewage pipeline facility by the flow meter or the flow meter, the water level obtained continuously, and the Manning formula. 2. Simple evaluation method of sewage unknown water described in 2.   The first pressure gauge is provided with a temperature measuring function or provided with a temperature measuring means for measuring the temperature of the sewage, and the constantly intruded water is based on the obtained measured value of the sewage temperature and the flow rate data. The simple evaluation method of the sewage unknown water of Claim 3 which evaluates a flow volume.