JP4131955B2 - Aeration air volume control device of sewage treatment plant - Google Patents

Description

  The present invention relates to an aeration air volume control device for a sewage treatment plant including aerobic tanks each having an aeration device and including a plurality of sewage treatment processes of the same treatment method.

  In conventional sewage treatment plants, organic substances were mainly removed by a process called activated sludge process. However, in recent years, eutrophication has progressed in closed water areas such as lakes and bays. There is an increasing demand for advanced treatment of sewage to remove nitrogen and phosphorus, which are eutrophication-causing substances.

  FIG. 10 is a treatment system diagram of this kind of sewage treatment plant, and FIG. 11 is a system diagram showing the arrangement of measuring devices of a conventional aeration air volume control device applied to this sewage treatment plant together with the treatment system. is there. The sewage treatment plant shown in FIG. 10 includes three treatment systems of series 1, series 2 and series 3. And the sewage sent from the water piping 50 is pumped by each series by No. 1 inflow pump 1, No. 2 inflow pump 101, and No. 3 inflow pump 201, respectively. Since series 1, series 2, and series 3 are configured identically, only the detailed configuration of series 1 will be described.

  The sewage sent from No. 1 inflow pump 1 flows into No. 1 first sedimentation site 2, where the suspended matter is settled. The outflow side of No. 1 first sedimentation site 2 is coupled to the inflow side of No. 1 anaerobic tank 10 by water pipe 51. A No. 1 anaerobic tank 11 and a No. 1 aerobic tank 12 are sequentially connected to the No. 1 anaerobic tank 10. The outflow side of the No. 1 aerobic tank 12 is connected to the inflow side of the No. 1 final sedimentation site 13 by a water pipe 52, and a water pipe 60 for sending treated water to the outflow side of the No. 1 final sedimentation site 13 Are combined. Further, a water pipe 53 is coupled to the circulating water outlet of the No. 1 aerobic tank 12, and the No. 1 circulation pump 14 supplies the circulating water to the No. 1 anaerobic tank 11 through the water pipe 53. ing. Further, a water pipe 54 and a water pipe 55 are connected to the No. 1 final sedimentation site 13, and among these, the No. 1 return pump 15 passes a part of the treated water of the No. 1 final sedimentation site 1 to No. 1. It returns to the anaerobic tank 10, and No. 1 surplus pump 17 discharges sludge through the water piping 55. FIG. Furthermore, No. 1 first sedimentation pump 18 is coupled to No. 1 first sedimentation site 2, and this No. 1 initial withdrawal pump 18 passes the sludge that has settled on No. 1 first sedimentation site 2 through water pipe 58. It is discharged together with the sludge of the surplus pump 17.

  As shown in FIG. 11, the No. 1 aerobic tank 12 is provided with the No. 1 aeration apparatus 9, and the No. 1 dissolved oxygen concentration meter 25 for control is installed in this. Then, the No. 2 dissolved oxygen concentration meter 125 is connected to the No. 2 aerobic tank (not shown) of the series 2 and the detailed dissolved explanation is omitted, and the No. 3 dissolved oxygen is added to the No. 3 aerobic tank (not shown) of the series 3. Each densitometer 225 is installed. In addition, in FIG. 10, the process provided with an anaerobic tank, an anaerobic tank, and an aerobic tank is generally called A20 process.

  FIG. 12 is a block diagram showing the configuration of a conventional aeration amount control device for controlling the aeration devices 9 of the series 1 to 3, and the dissolved oxygen concentration (hereinafter also referred to as DO) of the No. 1 aerobic tank 12 of the series 1. No. 1 control target value setter 31 for setting the target value, No. 2 control target value setter 131 for setting the dissolved oxygen concentration target value of the No. 2 aerobic tank of the series 2, and No. 3 aerobic tank of the series 3 No. 3 control target value setting unit 231 for setting the dissolved oxygen concentration target value of No. 1, and the dissolved oxygen concentration measured by No. 1 dissolved oxygen concentration meter 25 is the dissolved oxygen target of No. 1 control target value setting unit 31 The measured value of the dissolved oxygen concentration by the No. 1 DO controller 30 for calculating the aeration air volume target value of the No. 1 aeration apparatus 9 so as to follow the value and the No. 2 dissolved oxygen concentration meter 125 is obtained by the No. 2 control target value setting unit 131. The exposure of No. 2 aeration device 109 so as to follow the control target value The No. 3 aeration apparatus 209 so that the measured value of the dissolved oxygen concentration by the No. 2 DO controller 130 for calculating the air flow target value and the No. 3 dissolved oxygen concentration meter 225 follows the control target value of the No. 3 control target value setter 231. The No. 3 DO controller 230 for calculating the aeration air flow target value forms a set of controllers.

  FIGS. 11 and 12 show the installation position of the dissolved oxygen concentration meter and the control of the aeration apparatus in the case of controlling the dissolved oxygen concentration in the sewage treatment plant shown in FIG. 10, but ammonia instead of controlling the dissolved oxygen concentration. The nitrogen concentration can also be controlled. FIG. 13 shows the installation state of the ammonia meter in this case. In the figure, the same elements as those in FIG. In this case, the No. 1 ammonia meter 26 is installed in the No. 1 aerobic tank 12, and the No. 2 ammonia meter 126 is installed in the No. 2 aerobic tank (not shown) of the series 2 and the detailed configuration description is omitted. A No. 3 ammonia meter 226 is installed in a No. 3 aerobic tank (not shown).

  FIG. 14 is a block diagram showing the configuration of the aeration amount control device for controlling the aeration devices 9 of the series 1 to 3, and the first control for setting the target value of the ammonia nitrogen concentration in the first aerobic tank 12 of the series 1 Target value setter 41, No. 2 control target value setter 141 for setting the ammonia nitrogen concentration target value of the No. 2 aerobic tank of the series 2, and the ammonia nitrogen concentration target value of the No. 3 aerobic tank of the series 3 No. 3 control target value setting device 241 for setting the ammonia nitrogen concentration measured by the No. 1 ammonia meter 26 so as to follow the ammonia nitrogen concentration target value of the No. 1 control target value setting device 41. No. 2 aeration so that the measured value of the ammonia nitrogen concentration by No. 1 ammonia controller 40 and No. 2 ammonia meter 126 follow the control target value of No. 2 ammonia meter 126. The No. 3 aerator 209 controls the aeration amount of the device 109 and the No. 3 aeration device 209 so that the measured value of the dissolved oxygen concentration by the No. 3 ammonia meter 226 follows the control target value of the No. 3 control target value setter 241. No. 3 ammonia controller 240 that controls the above constitutes a set of controllers.

  Here, since the sewage treatment of the series 1, the series 2 and the series 3 is the same, the process in the series 1 will be described. The sewage supplied by the No. 1 inflow pump 1 settles a part of sludge at the No. 1 first sedimentation site 2, and the settled sludge is passed through the water pipe 58 by the No. 1 initial sedimentation pump 18 to the final sludge. It is sent to the discharge system. The No. 1 anaerobic tank 10, No. 1 anaerobic tank 11 and No. 1 anaerobic tank 12 are typical anaerobic-anoxic-aerobic processes (A20 process) that simultaneously remove organic matter, nitrogen and phosphorus. Hereinafter, the mechanisms for removing nitrogen and phosphorus in this process will be described separately.

(A) Removal of Nitrogen In the aerobic tank 12, using oxygen supplied from the aeration device 9, nitrifying bacteria convert ammonia nitrogen (NH ₄ -N) to nitrite nitrogen (NO ₂ -N), nitric acid Oxidizes to basic nitrogen (NO ₃ -N). Nitrite nitrogen (NO ₂ -N) and nitrate nitrogen (NO ₃ -N) sent to the anoxic tank 11 by the circulation pump 14 are removed from the organic matter in the inflowing sewage under nutrient-free conditions. It is reduced to nitrogen gas (N ₂ ) by nitrate respiration or nitrite respiration by nitrogen bacteria and removed out of the system.

When nitrogen removal reaction is expressed by chemical formula, nitrification reaction is
^{_{NH 4 + + 2O 2 → NO}} 2 - + 2H 2 O ... (1)
^{_{NO 2 - + 1 / 2O 2}} → NO 3 - ... (2)
As a denitrification reaction, the reaction when methanol is used as an organic substance is described.
^{_{6NO 3 - + 5CH 3 OH →}} 3N 2 + 5CO 2 + 7H 2 O + 6OH - ... (3)
It becomes.

(B) Removal of phosphorus In the anaerobic tank 10 arranged in the front stage of the aeration tank, phosphorus accumulating bacteria in the activated sludge accumulate organic acids such as acetic acid in the body and release phosphoric acid (PO ₄ ). The excessively released phosphorous phosphorus is used in the aerobic tank 12 arranged at the latter stage of the aeration tank, and the phosphorous phosphorus more than that released in the anaerobic tank 10 is utilized by the phosphorus excessive intake action of the phosphorus accumulating bacteria. Phosphorus is removed by absorbing activated carbon in activated sludge.

  In other words, an organic acid such as acetic acid is required to advance this reaction. When rainwater flows in, the organic acid concentration decreases and the organic matter that can be used by phosphorus-accumulating bacteria decreases, so that the phosphorus discharge reaction is not sufficiently performed, and the subsequent excessive intake of phosphorus may be insufficient. In some cases, the target water quality cannot be obtained only by removing biological phosphorus.

  Therefore, in order to compensate for this, a flocculant storage tank that stores flocculants such as polyaluminum chloride, aluminum sulfate, and iron sulfate is provided, and these flocculants are injected to add phosphorus components in the form of aluminum phosphate and iron phosphate. There is also a method of removing phosphorus by precipitation. The chemical formula in this case is expressed as follows.

Al ³⁺ + 3PO ₄ ⁻ → Al (PO ₄ ) ₃ (4)
In the sewage treatment plant, the return pump, circulation pump, surplus sludge extraction pump, and aeration device of each series are operated appropriately, and the return flow rate, circulation flow rate, surplus sludge extraction amount, and aeration air volume are controlled to appropriate values. Therefore, it is necessary to operate so that phosphorus and organic substances do not exceed the regulation values of the respective discharged water quality.

  Among these, the aeration apparatus 9 supplies dissolved oxygen necessary for removing nitrogen, phosphorus and organic substances by microorganisms, and accounts for 40 to 60% of the operating cost of the sewage treatment plant. If the supply amount of dissolved oxygen from the aeration apparatus 9 is too small, the water quality deteriorates. On the other hand, when the supply amount increases, the operation cost increases. That is, by appropriately controlling this aeration apparatus, it is possible to achieve maintenance of water quality and reduction of operating costs.

The conventional aeration air volume control device shown in FIGS. 11 and 12 uses the measured values of the dissolved oxygen concentration meters 25, 125, and 225 installed in the aerobic tanks of each series to the control target value setters 31, 131, and 231. The aeration devices 9, 109, and 209 are each controlled so as to have a set control target value (see, for example, Patent Document 1). On the other hand, another aeration air volume control device shown in FIG. 13 and FIG. 14 uses the No. 1 ammonia meter 26, 126, 226 installed in the No. aerobic tank of each series as the No. 1 control target value setter. The aeration apparatuses 9, 109, and 209 are controlled so as to have control target values set in 41, 141, and 142 (see, for example, Patent Document 2).
JP 11-244894 A JP 2003-200190 A

  The aeration air flow control device shown in FIGS. 11 and 12 uses a dissolved oxygen concentration meter that is cheaper and easier to maintain than an ammonia meter, and has a low initial cost and is easy to maintain. Since control is performed based on an indirect index of oxygen, it is necessary to operate at a high target value of dissolved oxygen in order to always maintain the quality of discharged water, and the operating cost for aeration increases.

  On the other hand, the aeration air volume control device shown in FIGS. 13 and 14 is higher in initial cost than the devices shown in FIGS. 11 and 12, and the maintenance of the sensor is difficult. On the other hand, since the nitrification rate of nitrifying bacteria is usually slower than the removal rate of organic matter and phosphorus, if the oxygen necessary for nitrification is supplied, the air volume necessary for the removal of organic matter, phosphorus and nitrogen can be secured. Based on the idea, since the amount of aeration air is controlled using the ammoniacal nitrogen concentration as an index, it is possible to perform an operation that reduces the operating cost for aeration while maintaining the discharged water quality.

  The present invention has been made in order to solve the above-described problems. In a sewage treatment plant having a plurality of series of advanced treatment processes, the present invention is more aerated than an aeration air volume control device that controls dissolved oxygen using a dissolved oxygen concentration meter. Aeration at a sewage treatment plant that can reduce operating costs and lower initial costs and maintenance management costs than an aeration air volume control device that controls ammonia nitrogen concentration using an ammonia meter of each series. An object is to provide an air volume control device.

The invention according to claim 1
In an aeration air volume control device of a sewage treatment plant including an aerobic tank having an aeration device that operates according to an aeration air volume target value, and having a plurality of sewage treatment processes of the same treatment method,
Flow rate control means for controlling the flow rate of sewage flowing into all systems to be equal;
An ammonia meter that measures the ammoniacal nitrogen concentration in the aerobic tank of any one of a plurality of series;
A dissolved oxygen concentration meter that measures the dissolved oxygen concentration of all series of aerobic tanks of multiple series;
First target value setting means for setting the ammonia nitrogen concentration target value of the treated water;
Based on the dissolved oxygen concentration measured by the dissolved oxygen concentration meter of the aerobic tank of the series where the ammonia meter is installed, the dissolved oxygen concentration target value of the other series of aerobic tanks where the ammonia meter is not installed is set. Second target value setting means for
The aeration device of the aerobic tank in which the ammonia meter is installed calculates the aeration air flow target value that brings the measured value of the ammonia nitrogen concentration close to the ammonia nitrogen concentration target value, and the aerobic tank in which the ammonia meter is not installed. A controller for calculating an aeration air volume target value that brings the measured value of the dissolved oxygen concentration closer to the dissolved oxygen concentration target value,
An aeration air volume control device for a sewage treatment plant.

The invention according to claim 2
In an aeration air volume control device of a sewage treatment plant including an aerobic tank having an aeration device that operates according to an aeration air volume target value, and having a plurality of sewage treatment processes of the same treatment method,
Flow rate control means for controlling the flow rate of sewage flowing into all systems to be equal;
An ammonia meter that measures the ammoniacal nitrogen concentration in the aerobic tank of any one of a plurality of series;
Target value setting means for setting the ammonia nitrogen concentration target value of the treated water;
Aeration efficiency input means for inputting the aeration efficiency of the aeration apparatus for each series, and other series for the aeration apparatus of the aerobic tank of the series where the ammonia meter is installed based on the inputted aeration efficiency. An aeration efficiency ratio calculating means for obtaining an aeration efficiency ratio of each aeration apparatus of the aerobic tank;
A controller for calculating an aeration air volume target value that brings the measured value of the ammonia nitrogen concentration closer to the ammonia nitrogen concentration target value, the aeration apparatus of the aerobic tank in which the ammonia meter is installed,
Aeration air volume calculation means for calculating the aeration air volume target value of the aeration apparatus of the aerobic tank in which the ammonia meter is not installed by multiplying the aeration air volume target value calculated by the controller by the aeration efficiency ratio;
An aeration air volume control device for a sewage treatment plant.

The invention according to claim 3
In an aeration air volume control device of a sewage treatment plant including an aerobic tank having an aeration device that operates according to an aeration air volume target value, and having a plurality of sewage treatment processes of the same treatment method,
An inflow flow meter that measures the flow rate of sewage flowing into each series;
An ammonia meter that measures the ammoniacal nitrogen concentration in the aerobic tank of any one of a plurality of series;
Target value setting means for setting the ammonia nitrogen concentration target value of the treated water;
The aeration efficiency input means for inputting the aeration efficiency of the aeration apparatus for each series, and the other aeration apparatus of the aerobic tank of one series in which the ammonia meter is installed based on the inputted aeration efficiency. An aeration efficiency ratio calculating means for obtaining an aeration efficiency ratio of each of the aeration apparatuses of the aerobic tank of the series;
A controller for calculating an aeration air volume target value that brings the measured value of the ammonia nitrogen concentration closer to the ammonia nitrogen concentration target value, the aeration apparatus of the aerobic tank in which the ammonia meter is installed,
An air magnification calculating means for calculating the air magnification of the series from the flow rate of sewage flowing into the series including the aerobic tank in which the ammonia meter is installed and the aeration volume of the aeration apparatus;
Multiplying the aeration air volume target value calculated by the controller by the air magnification, the aeration air volume target value obtained by this multiplication, the value obtained by multiplying the input aeration efficiency by the aeration efficiency ratio, and the inflowing sewage An aeration air volume calculating means for calculating an aeration air volume target value of an aeration apparatus of an aerobic tank in which an ammonia meter is not installed, based on a flow rate measurement value;
An aeration air volume control device for a sewage treatment plant.

The invention according to claim 4 is the aeration air volume control device for a sewage treatment plant according to any one of claims 1 to 3,
An inflow flow meter for measuring the total inflow of sewage flowing into the sewage treatment plant,
A total nitrogen meter that measures the total nitrogen concentration of the incoming sewage,
And the first target value setting means or the target value setting means sets the ammonia nitrogen concentration target value of the treated water based on both or either of the measured total inflow of sewage and / or the total nitrogen concentration. It is characterized by setting.

The invention according to claim 5 is the aeration air volume control device for a sewage treatment plant according to any one of claims 1 to 4,
A dissolved oxygen concentration meter that measures the dissolved oxygen concentration of all series,
A limiter device for setting the upper and lower limit values of the dissolved oxygen concentration and controlling the aeration air volume so that the measured dissolved oxygen concentration of each series does not deviate from the upper and lower limit values;
It is provided with.

  By configuring the present invention as described above, the operating cost for aeration is reduced in a sewage treatment plant having multiple series of advanced treatment processes, compared to an aeration air volume control device that controls dissolved oxygen using a dissolved oxygen concentration meter. An aeration air volume control device for a sewage treatment plant that can reduce the initial cost and the maintenance cost compared to an aeration air volume control device that can control the ammoniacal nitrogen concentration using an ammonia meter of each series. Provided.

  Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings.

  FIG. 1 is a system diagram showing a treatment system of a sewage treatment plant to which a first embodiment of an aeration air volume control device according to the present invention is applied together with an arrangement of measuring instruments, and FIG. 11 or FIG. The same elements as those in Fig. 13 are denoted by the same reference numerals, and the description thereof is omitted. Here, a No. 1 dissolved oxygen concentration meter 25 and an ammonia meter 26 are installed to control the aeration apparatus of each series of aerobic tanks. The No. 2 dissolved oxygen concentration meter 125 is connected to the No. 2 aerobic tank (not shown) of the series 2 and the detailed dissolved explanation is omitted, and the No. 3 dissolved oxygen is added to the No. 3 aerobic tank (not shown) of the series 3. The configuration of the densitometer 225 is different from that of FIG. 11 or FIG. 13, and the other configuration is the same as that of FIG. 11 or FIG. 13. The No. 1 dissolved oxygen concentration meter 25, the ammonia meter 26, the No. 2 dissolved oxygen concentration meter 125 and the No. 3 dissolved oxygen concentration meter 225 are installed at the same position in the sewage flow direction.

  FIG. 2 is a block diagram showing the configuration of the first embodiment of the aeration air volume control device applied to the sewage treatment plant. This apparatus is based on the measured value of the No. 1 control target value setter 41 for setting the target value of the ammonia nitrogen concentration of the No. 1 aerobic tank 12 of the No. 1 series and the No. 1 dissolved oxygen concentration meter 25. Based on the measurement value of the No. 2 control target value calculator 132 that calculates the dissolved oxygen concentration target value of the No. 2 aerobic tank and the No. 1 dissolved oxygen concentration meter 25, the dissolved oxygen concentration target of the No. 3 aerobic tank of Series 3 A No. 2 control target value calculator 232 for calculating a value, and the measured value of the ammonia nitrogen concentration by the ammonia meter 26 follows the target value of the ammonia nitrogen concentration of the No. 1 control target value setter 41 The measured value of the dissolved oxygen concentration by the No. 1 ammonia controller 40 that controls the aeration amount of the No. 1 aeration apparatus 9 and the No. 2 dissolved oxygen concentration meter 125 follows the control target value of the No. 2 control target value calculator 132. No. 2 aeration tank 109 exposure The No. 3 aeration apparatus 209 is controlled so that the measured value of the dissolved oxygen concentration by the No. 2 DO controller 130 for controlling the amount and the No. 3 dissolved oxygen concentration meter 225 follows the control target value of the No. 3 control target value calculator 232. No. 3 DO controller 230, which constitutes one controller.

  In this case, No. 1 dissolved oxygen concentration meter 25 is connected to each input terminal of No. 2 control target value calculator 132 and No. 3 control target value calculator 232 by signal line 25a. The output terminals of the No. 1 control target value setter 41, No. 2 control target value calculator 132 and No. 3 control target value calculator 232 are connected to the No. 1 ammonia controller 40, No. 2 DO by signal lines 41a, 132a and 232a, respectively. The No. 1 ammonia meter 26, the No. 2 dissolved oxygen concentration meter 125 and the No. 3 dissolved oxygen concentration meter 225 are connected to one input terminal of each of the controller 130 and the No. 3 DO controller 230, and the No. 1 signal line 26a, 125a and 225a The ammonia controller 40 is connected to the other input terminals of the No. 2 DO controller 130 and the No. 3 DO controller 230. Further, the output terminals of No. 1 ammonia controller 40, No. 2 DO controller 130 and No. 3 DO controller 230 are connected to No. 1 aeration apparatus 9, No. 2 aeration apparatus 109 and No. 3 aeration apparatus 209 by signal lines 26b, 125b and 225b. It is connected.

The operation of the first embodiment configured as described above will be described below, particularly focusing on the parts that differ from the conventional apparatus. Sewage flowing into the sewage treatment plant is supplied from the water pipe 50 to the series 1, 2, 3 by the No. 1 inflow pump 1, No. 2 inflow pump 101 and No. 3 inflow pump 201. The No. 1 inflow pump 1, No. 2 inflow pump 101 and No. 3 inflow pump 201 are controlled by a control device (not shown) so that the inflow amount flowing into each series becomes equal. The measured value of the No. 1 ammonia meter 26 installed in the No. 1 aerobic tank 12 is transmitted to the No. 1 ammonia controller 40 via the signal line 26a. In order to follow the ammonia nitrogen concentration target value set in the No. 1 control target value setter 41, the No. 1 ammonia controller 40 is operated by, for example, a PI controller as shown in Equations (5) and (6). 9 is calculated.

However,
Qair1 (t): No.1 aeration air flow target value at time t (m ³ / min)
Qair ₀₁ : Initial value of No. 1 aeration air volume (m ³ / min)
Kp: Proportional gain (m ⁶ / g · min)
T _I : Integration constant (min)
Δt: Control cycle (min)
e (t): Deviation (mg / L)
SV _NH41 (t): No.1 ammonia nitrogen concentration target (mg / L)
PV _NH41 (t): Ammonia meter measurement (mg / L)
It is.

  The No. 1 aeration apparatus 9 adjusts the air volume by adjusting the opening of the air volume control valve and controlling the inverter of the aeration apparatus (blower) so as to follow the air volume target value calculated by the equations (5) and (6). The measured value of the No. 1 aerobic tank dissolved oxygen concentration meter 25 at this time is transmitted to the No. 2 control target value calculator 132 and the No. 3 control target value calculator 232 via the signal line 25a.

The No. 2 control target value calculator and the No. 3 control target value calculator are values obtained by filtering the measured value of the dissolved oxygen meter 25 according to the equation (7) at a constant period (5 to 30 minutes). The data is transmitted to the No. 2 DO controller 130 and the No. 3 DO controller 230 via the line 232a.

However,
PVf _O2 (t): Unit 1 dissolved oxygen concentration filtering value at time t
PV _O2 (t): Unit 1 dissolved oxygen concentration measurement value at time t
n: An integer.

The No. 2 DO controller 130 and the No. 3 DO controller 230 are, for example, PI controllers as shown in equations (8) and (9) so as to follow the output value from the No. 2 control target value calculator and the No. 3 control target value calculator. The air volume target values of the No. 2 aeration apparatus 109 and No. 3 aeration apparatus 209 are calculated by the above.

However,
Qairn (t): No. n aeration target value at time t (m ³ / min)
Qair _0n : Initial value of No. n aeration air volume (m ³ / min)
Kp: Proportional gain (m ⁶ / g · min)
T _I : Integration constant (min)
Δt: Control cycle (min)
e (t): Deviation (mg / L)
SV _O2n (t): No. n dissolved oxygen concentration target value (mg / L)
PV _O2n (t): No. n dissolved oxygen concentration meter measurement value (mg / L) (n = 2, 3)
It is.

  The No. 2 aeration apparatus 109 and No. 3 aeration apparatus 209 adjust the opening of the air volume control valve and control the inverter of the aeration apparatus (blower) so as to follow the air volume target values calculated by the equations (8) and (9), respectively. Adjust air volume with.

  Thus, according to the first embodiment, compared with the apparatus shown in FIG. 13 and FIG. 14, the number of ammonia meters having a high initial cost and complicated maintenance is reduced. Since the air volume of No. 3 aerobic tank is controlled by a variable DO target value, an air volume reduction effect can be expected as compared with the apparatus shown in FIGS.

  Further, since the control is performed so that the DO of each series becomes equal, the present invention can be applied even when the aeration efficiency of the aeration apparatus is different. In particular, when a pond is added, an aeration apparatus with different aeration efficiency may be installed, and this control method is effective.

  FIG. 3 is a system diagram showing the treatment system of the sewage treatment plant to which the second embodiment of the aeration air volume control device according to the present invention is applied, together with the arrangement of measuring instruments. In FIG. Are denoted by the same reference numerals, and description thereof is omitted. Here, in order to control the aeration apparatus of each series of aerobic tanks, only the ammonia meter 26 is installed in the No. 1 aerobic tank 12 of the series 1 and dissolved in any of the aerobic tanks of the series 1, 2 and 3. The configuration is different from that in FIG. 1 in that no oxygen concentration meter is installed.

  FIG. 4 is a block diagram showing the configuration of the aeration air volume control device according to the second embodiment. Here, the No. 1 ammonia meter 26 is connected to one input end of the No. 1 ammonia controller 40 by a signal line 26a, and the No. 1 control target value setter 41 is connected to the other input end of the No. 1 ammonia controller 40 by a signal line 41a. The output end of the No. 1 ammonia controller 40 is connected to the No. 1 aeration device 9 by a signal line 26b. In addition, the No. 1 aeration device aeration efficiency input unit 43, the No. 2 aeration device aeration efficiency input unit 143 and the No. 3 aeration device aeration efficiency input unit 243 for presetting the aeration efficiencies of the series 1, 2 and 3 are provided. Newly added No. 1 to No. 2 aeration efficiency ratio calculating unit 144 for calculating the aeration efficiency ratio of No. 2 aeration device 109 to No. 1 aeration device aeration efficiency input unit 43 and No. 1 aeration A No. 1 to No. 3 aeration efficiency ratio calculation unit 244 that calculates an aeration efficiency ratio of the No. 3 aeration apparatus 209 is provided for the apparatus aeration efficiency input unit 43. Further, the No. 2 aeration air amount calculation unit 145 that calculates the aeration air amount of the No. 2 aeration apparatus 109 by multiplying the aeration air amount output from the No. 1 ammonia controller 40 by the output of the No. 1 vs. No. 2 aeration efficiency ratio calculation unit 144. And a No. 3 aeration air volume calculation unit 245 that calculates the aeration air volume of the No. 3 aeration apparatus 209 by multiplying the aeration air volume output from the No. 1 ammonia controller 40 by the output of the No. 1 vs. No. 3 diffusion efficiency ratio calculation unit 244. These output terminals are connected to the No. 2 aeration apparatus 109 and No. 3 aeration apparatus 209 through signal lines, respectively.

The operation of the second embodiment configured as described above will be described below. The sewage flowing into the sewage treatment plant is supplied from the series 1 to the series 3 by the No. 1 inflow pump 1, the No. 2 inflow pump 101, and the No. 3 inflow pump 201 from the water pipe 50. The No. 1 to No. 3 inflow pumps are controlled by control means (not shown) so that the inflow amounts flowing into each series are equal. The measured value of the ammonia meter 26 installed in the No. 1 aerobic tank 12 is transmitted to the No. 1 ammonia controller 40 through a signal line 26a. The No. 1 ammonia controller 40 is adapted to follow the ammonia nitrogen concentration target value set in the No. 1 control target value setter 41, for example, by the PI controller as shown in the equations (10) and (11), the air volume of the No. 1 aeration apparatus 9 Calculate the target value.

However,
Qair1 (t): No.1 aeration air flow target value at time t (m ³ / min)
Qair ₀₁ : Initial value of No. 1 aeration air volume (m ³ / min)
Kp: Proportional gain (m ⁶ / g · min)
T _I : Integration constant (min)
Δt: Control cycle (min)
e (t): Deviation (mg / L)
SV _NH41 (t): No.1 ammonia nitrogen concentration target (mg / L)
PV _NH41 (t): Ammonia meter measurement (mg / L)
It is.

  The No. 1 aeration apparatus 9 adjusts the air volume by adjusting the opening of the air volume control valve and controlling the inverter of the aeration apparatus (blower) so as to follow the aeration air volume target value calculated by the equations (10) and (11). In addition, the No. 1 No. 2 diffuser efficiency ratio calculating unit 144 and No. 1 No. 3 diffused efficiency ratio calculating unit are controlled by an ammonia meter based on the input diffused efficiency based on the calculations shown in the equations (12) and (13). The aeration efficiency ratio between the series (series 1) and other series is calculated.

C ₁₂ = Kl ₂ / Kl ₁ (12)
C ₁₃ = Kl ₃ / Kl ₁ (13)
However,
C ₁₂ : 1 No.2 diffuse efficiency ratio
C ₁₃ : 1 No. 3 diffuse efficiency ratio
Kl ₁ : 1 Aeration system diffuser efficiency
Kl ₂ : Aeration efficiency of No.2 aerator
Kl ₃ : No. 3 aeration device.

  The aeration efficiency ratio calculated here is transmitted to the No. 2 aeration air volume calculation unit and No. 3 aeration air volume calculation unit, respectively, together with the No. 1 aeration air volume target value at time t calculated by the equations (10) and (11). , (14) and (15) are used to calculate the aeration air volume target value.

Qair2 (t) ＝ C ₁₂・ Qair1 (t) (14)
Qair3 (t) ＝ C ₁₃・ Qair1 (t) (15)
However,
Qairn (t): No. n aeration air flow target value at time t (m ³ / min) (n = 1 to 3)
C ₁₂ : 1 No.2 diffuse efficiency ratio
C ₁₃ : No. 1 No. 3 air diffusion efficiency ratio.

  The No. 2 aeration device 109 and No. 3 aeration device 209 adjust the opening of the air volume control valve and the inverter control of the aeration apparatus (blower) so as to follow the target air volume calculated by the equations (14) and (15), respectively. Adjust the air volume.

  Thus, according to the second embodiment, it is necessary to set an accurate air diffusion efficiency in the input unit in advance, but the initial cost is lower than that of the conventional aeration air volume control device shown in FIGS. 13 and 14. It is possible to reduce the number of ammonia meters that are expensive and complicated to maintain, and to control the air volume of the No. 2 aeration apparatus 109 in the series 2 and the No. 3 aeration apparatus 209 in the series 3. Further, unlike the first embodiment, the dissolved oxygen concentration meter is not used for the control, and only the ammonia meter is used. Therefore, there is no control abnormality due to the abnormality of the dissolved oxygen concentration meter, and the stability is improved.

  FIG. 5 is a system diagram showing the treatment system of the sewage treatment plant to which the third embodiment of the aeration air volume control device according to the present invention is applied, together with the arrangement of measuring instruments. In FIG. Are denoted by the same reference numerals, and description thereof is omitted. Here, the No. 1 inflow flow meter 5 is connected to the sewage delivery side of the No. 1 inflow pump 1 of the series 1, and the No. 2 inflow flow meter 105 is connected to the sewage delivery side of the No. 2 inflow pump 101 of the series 1. 3 is different from FIG. 3 in that a No. 3 inflow flow meter 205 is provided on the sewage outflow side of the inflow pump 201.

  FIG. 6 is a block diagram showing the configuration of the aeration air volume control device according to the third embodiment. In the figure, the same elements as those in FIG. 4 showing the second embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the second embodiment shown in FIG. 4, the aeration air volume target value of the No. 1 ammonia controller 40 is input as one input, and the measured value of the No. 1 inflow flow meter 5 is input as the other, and the aeration air volume ratio of the No. 1 aeration apparatus 9 is calculated. A No. 1 air magnification calculation unit 246 is newly provided, and a No. 2 aeration air amount calculation unit 145 is provided for the No. 1 vs. No. 2 diffuser efficiency ratio calculation unit 144, No. 2 inflow flow meter 105 and No. 1 air magnification calculation unit 246. Based on each output, the aeration air volume target value for the No. 2 aeration device 109 is calculated, and the No. 3 aeration air quantity calculation unit 245 is operated by the No. 1 vs. No. 3 aeration efficiency ratio calculation unit 244, No. 3 inflow flow meter 205 and No. 1 air. 4 is different from the second embodiment shown in FIG. 4 in that the aeration air volume target value for the No. 3 aeration apparatus 209 is calculated based on each output of the magnification calculation unit 246. Other than that, FIG. It is configured identically.

The operation of the third embodiment configured as described above will be described below. The sewage flowing into the sewage treatment plant is supplied from the series 1 to the series 3 by the No. 1 inflow pump 1, the No. 2 inflow pump 101, and the No. 3 inflow pump 201 from the water pipe 50. The measured value of the ammonia meter 26 installed in the No. 1 aerobic tank 12 is transmitted to the No. 1 ammonia controller 40 through a signal line 26a. The No. 1 ammonia controller 40 is adapted to follow the ammonia nitrogen concentration target value set in the No. 1 control target value setter 41, for example, by the PI controller as shown in the equations (16) and (17), the air volume of the No. 1 aeration apparatus 9 Calculate the target value.

However,
Qair1 (t): No.1 aeration air flow target value at time t (m ³ / min)
Qair ₀₁ : Initial value of No. 1 aeration air volume (m ³ / min)
Kp: Proportional gain (m ⁶ / g · min)
T _I : Integration constant (min)
Δt: Control cycle (min)
e (t): Deviation (mg / L)
SV _NH41 (t): No.1 ammonia nitrogen concentration target (mg / L)
PV _NH41 (t): Ammonia meter measurement (mg / L)
It is.

  The No. 1 aeration apparatus 9 adjusts the air volume by adjusting the opening of the air volume control valve and controlling the inverter of the aeration apparatus (blower) so as to follow the aeration air volume target value calculated by the equations (16) and (17).

In addition, the No. 1 No. 2 diffused efficiency ratio calculating unit 144 and No. 1 No. 3 diffused efficiency ratio calculating unit are controlled by an ammonia meter based on the input diffused efficiency based on the calculations shown in the equations (18) and (19). The aeration efficiency ratio between the series (series 1) and other series is calculated.

C ₁₂ = Kl ₂ / Kl ₁ (18)
C ₁₃ = Kl ₃ / Kl ₁ (19)
However,
C ₁₂ : 1 No.2 diffuse efficiency ratio
C ₁₃ : 1 No. 3 diffuse efficiency ratio
Kl ₁ : 1 Aeration system diffuser efficiency
Kl ₂ : Aeration efficiency of No.2 aerator
Kl ₃ : No. 3 aeration device.

  On the other hand, the No. 1 air magnification calculator calculates the No. 1 air magnification from the measured value of No. 1 inflow flow meter 5 and the No. 1 aeration air flow target value calculated from Equations (16) and (17) according to Equation (20). The

A1 (t) = Qair1 (t) / Qin1 (t) (20)
However,
A1 (t): No.1 air magnification calculation value
Qair1 (t): No.1 aeration air flow target value at time t (m ³ / min)
Qin ₁ (t): Unit ₁ inflow rate (m ³ / min)
It is.

  The No. 1 air magnification calculated here is No. 1 No. 2 diffused efficiency ratio calculated by the formulas (18) and (19), No. 1 No. 3 diffused efficiency ratio, No. 2 inflow flow meter 105, No. 3 inflow The measured value of the flow meter 205 is transmitted to the No. 2 aeration air volume calculation unit and No. 3 aeration air volume calculation unit, respectively, and the aeration air volume target value is calculated by the equations (21) and (22).

Qair2 (t) ＝ C ₁₂・ A1 (t) ・ Qin ₂ (t) (21)
_{Qair3 (t) = C 13 ·} A1 (t) · Qin 3 (t) ... (22)
However,
Qair2 (t): No. 2 aeration air flow target value at time t (m ³ / min)
Qair3 (t): No. 3 aeration air volume target value at time t (m ³ / min)
C ₁₂ : 1 No.2 diffuse efficiency ratio
C ₁₃ : 1 No. 3 diffuse efficiency ratio
A1 (t): No.1 air magnification calculation value
Qin ₂ (t): Unit ₂ inflow flow rate at time t (m ³ / min)
Qin ₃ (t): No. 3 inflow rate at time t (m ³ / min)
It is.

  The No. 2 aeration device 109 and No. 3 aeration device 209 adjust the opening of the air volume control valve and the inverter control of the aeration apparatus (blower) so as to follow the air volume target values calculated by the equations (21) and (22), respectively. Adjust the air volume.

  Thus, according to the third embodiment, compared with the conventional aeration air volume control device shown in FIG. 13 and FIG. 14, the number of ammonia meters which are high in initial cost and complicated to maintain is reduced. It becomes possible to control the air volume of the aeration apparatus 109 and the No. 3 aeration apparatus 209 of the series 3. Further, unlike the first embodiment, the dissolved oxygen concentration meter is not used for the control, and only the ammonia meter is used. Therefore, there is no control abnormality due to the abnormality of the dissolved oxygen concentration meter, and the stability is improved. Furthermore, as compared with the first embodiment and the second embodiment, there is also a new effect that it is possible to control even when the amount of sewage flowing into each series is different.

FIG. 7 is a system diagram showing the treatment system of the sewage treatment plant to which the fourth embodiment of the aeration air volume control device according to the present invention is applied, together with the arrangement of measuring instruments. In FIG. Are denoted by the same reference numerals, and description thereof is omitted. Here, the inflow flow meter 3 and the inflow total nitrogen meter 4 for measuring the inflowing nitrogen are connected to the original water pipe for dividing the sewage by the No. 1 inflow pump 1, the No. 2 inflow pump 101 and the No. 3 inflow pump 201. Provided, the inflow flow meter measurement value and the inflow total nitrogen meter measurement value are multiplied by, for example, multiplication means (not shown), and the obtained nitrogen load amount information is taken into the No. 1 ammonia controller 40 (see FIG. 1). For example, the air volume target value of the No. 1 aeration apparatus is calculated by calculating the equations (23), (24), and (25). Thus, the calculation of the air volume target value of the aeration apparatus using the nitrogen load information is not limited to the first embodiment, and can be applied to both the second and third embodiments. It is.

However,
Qair1 (t): No.1 aeration air flow target value at time t (m ³ / min)
Aair1 (t): 1 nitrogen load multiplication factor calculation value (m ³ / g)
TN (t): Total nitrogen meter measurement (mg / L)
Qin (t): Inflow flow meter measurement (m ³ / min)
Aair ₀₁ : Initial value of No. 1 nitrogen load air magnification factor
Kp: Proportional gain (m ⁶ / g ² )
T _I : Integration constant (min)
Δt: Control cycle (min)
e (t): Deviation (mg / L)
SV _NH41 (t): No.1 ammonia nitrogen concentration target (mg / L)
PV _NH41 (t): Ammonia meter measurement (mg / L)
It is.

  In addition, the measurement of inflow total nitrogen may be provided in the piping of the front | former stage or back | latter stage of each first sedimentation place of series 1, 2, and 3, and each measured value may be added. Furthermore, in Examples 1-3, since the inflow flow rate is controlled so as to be equal to each pond, the flow rate of each series is not limited to a flowmeter that measures the overall flow rate as in this example. It is possible to measure the total nitrogen flowing in just by measuring.

  Thus, according to the fourth embodiment, in addition to the effect that the operating cost for aeration can be reduced and the initial cost and the maintenance cost can be kept low, the nitrogen load information on the inflowing sewage Therefore, a new effect that the target value followability of ammonia nitrogen concentration control is improved can be obtained.

  FIG. 8 is a system diagram showing the treatment system of the sewage treatment plant to which the fifth embodiment of the aeration air volume control device according to the present invention is applied, together with the arrangement of measuring instruments. In the figure, the third embodiment is applied. The same elements as those in FIG. 5 are denoted by the same reference numerals, and the description thereof is omitted. Here, the No. 1 dissolved oxygen concentration meter 25 is provided in addition to the No. 1 ammonia meter 26 in the No. 1 aerobic tank 12 of the series 1, and the No. 2 dissolved oxygen concentration meter is provided in the No. 2 aerobic tank of which the illustration of the series 2 is omitted. 125 is different from FIG. 5 in that the No. 3 dissolved oxygen concentration meter 225 is provided in the No. 3 aerobic tank in which the illustration of Series 3 is omitted, and the other configuration is exactly the same as FIG. .

  FIG. 9 is a block diagram showing the configuration of the aeration air volume control device according to the fifth embodiment. In the figure, the same elements as those in FIG. 6 showing the third embodiment are denoted by the same reference numerals, and the description thereof is omitted. In this embodiment, the No. 1 DO limiter device 47 is provided at the output stage of the No. 1 ammonia controller 40, No. 2 aeration air amount calculation unit 145 and No. 3 aeration air amount calculation unit 245 constituting the third embodiment shown in FIG. The configuration is the same as that of FIG. 6 except that the No. 2 DO limiter device 147 and the No. 3 DO limiter device 247 are provided. In addition, the 1 DO limiter device 47, the 2 DO limiter device 147 and the 3 DO limiter device 247 are measured values of the No. 1 dissolved oxygen concentration meter 25, the No. 2 dissolved oxygen concentration meter 125 and the No. 3 dissolved oxygen concentration meter 225, respectively. Based on the above, the air flow target value of each series of aeration devices is limited.

The operation of the fifth embodiment configured as described above will be described below. In the No. 1 DO limiter device 47, the No. 2 DO limiter device 147 and the No. 3 DO limiter device 247, a lower limit value and an upper limit value of the dissolved oxygen concentration are set. When the measured values of the No. 1 dissolved oxygen concentration meter 25, No. 2 dissolved oxygen concentration meter 125 and No. 3 dissolved oxygen concentration meter 225 are between the set upper and lower limit values, the operation is performed as in the third embodiment. However, when the measured values of No. 1 dissolved oxygen concentration meter 25, No. 2 dissolved oxygen concentration meter 125 and No. 3 dissolved oxygen concentration meter 225 deviate from the set upper and lower limit values, (26), (27) As shown in the equations (29) and (30), the No. 1 DO limiter device 47, 2 is switched over so that the DO does not deviate from the upper and lower limits by switching to a constant dissolved oxygen concentration control with the lower limit or upper limit as a target value. The No. DO limiter device 147 and the No. 3 DO limiter device 247 operate. The calculation formulas of the DO limiter device are shown in formulas (26) to (30).

However,
Q´airn (t): No. n aeration target output value at time t (m ³ / min)
Q´air _0n : Initial value of No. n aeration air volume (m ³ / min),
Qairn (t): No. aeration air volume target DO limiter device input value at time t (m ³ / min)
Kp: Proportional gain (m ⁶ / g · min)
T _I : Integration constant (min)
Δt: Control cycle (min)
e (t): Deviation (mg / L)
DOmin: Lower limit of dissolved oxygen concentration (mg / L)
DOmax: Upper limit of dissolved oxygen concentration (mg / L)
PV _O2n (t): No. n dissolved oxygen concentration meter measurement value (mg / L) (n = 1-3)
It is.

  Thus, according to the fifth embodiment, when the dissolved oxygen concentration exceeds the lower limit value or the upper limit value, the dissolved oxygen concentration can be switched to the constant control with the lower limit value or the upper limit value as the target value, and the treated water quality can be kept constant. Can be kept in range.

  In addition, although each said embodiment applied to what the processing system of a sewage-treatment plant has A20 process, this invention is not limited to this, A standard activated sludge process, a circulation type nitrification denitrification process, AO Any treatment system may be used as long as it is a sewage treatment process that performs aeration, such as a process, a carrier input type process, and a step inflow process.

  Further, the number of series is not limited to 3 series as in the embodiment, and any number of series can be applied as long as it is 2 series or more.

  Furthermore, the aeration apparatus is a device that supplies air to a plurality of systems from one aeration apparatus, as in the above embodiment, and controls the air regulating valve on the piping. The aeration air volume may be adjusted.

  Furthermore, the installation position of the ammonia meter may be any part of the aerobic tank in which aeration is performed.

The system diagram which showed the processing system of the sewage treatment plant to which the 1st Example of the aeration air volume control apparatus which concerns on this invention is applied with the arrangement | positioning of a measuring device. The block diagram which shows the structure of 1st Example of the aeration air volume control apparatus which concerns on this invention. The system diagram which showed the processing system of the sewage treatment plant to which 2nd Example of the aeration air volume control apparatus which concerns on this invention is applied with the arrangement | positioning of a measuring device. The block diagram which shows the structure of 2nd Example of the aeration air volume control apparatus which concerns on this invention. The system diagram which showed the processing system of the sewage treatment plant to which the 3rd Example of the aeration air volume control apparatus which concerns on this invention is applied with the arrangement | positioning of a measuring device. The block diagram which shows the structure of 3rd Example of the aeration air volume control apparatus which concerns on this invention. The system diagram which showed the processing system of the sewage treatment plant which applies this as a 4th Example of the aeration air volume control apparatus which concerns on this invention with arrangement | positioning of a measuring device. The system diagram which showed the processing system of the sewage treatment plant to which 5th Example of the aeration air volume control apparatus which concerns on this invention is applied with the arrangement | positioning of a measuring device. The block diagram which shows the structure of 5th Example of the aeration air volume control apparatus which concerns on this invention. System diagram of a sewage treatment plant that removes nitrogen and phosphorus in addition to organic matter. The system diagram which showed arrangement | positioning of the measuring device of the conventional aeration air volume control apparatus applied to the sewage treatment plant shown in FIG. The block diagram which shows the structure of the conventional aeration air volume control apparatus using the measuring device of FIG. The system diagram which showed arrangement | positioning of the measuring device of another conventional aeration air volume control apparatus applied to the sewage treatment plant shown in FIG. The block diagram which shows the structure of another conventional aeration air volume control apparatus using the measuring device of FIG.

Explanation of symbols

1 No. 1 inflow pump 2 No. 1 first sedimentation basin 3 Inflow flow meter 4 Inflow total nitrogen meter 9 No. 1 aeration device 10 No. 1 anaerobic tank 11 No. 1 anaerobic tank 12 No. 1 aerobic tank 13 No. 1 final sedimentation tank 14 1 No. 1 circulation pump 15 No. 1 return pump 17 No. 1 surplus pump 18 No. 1 initial withdrawal pump 25 No. 1 dissolved oxygen concentration meter 125 No. 2 dissolved oxygen concentration meter 225 No. 3 dissolved oxygen concentration meter 26 Ammonia meter 101 No. 2 inflow pump 201 No. 3 inflow pump 109 No. 2 aeration device 209 No. 3 aeration device 40 No. 1 ammonia controller,
130 No. 2 DO controller 230 No. 3 DO controller 43 No. 1 diffused efficiency input unit 143 No. 2 diffused efficiency input unit No. 2433 Diffused efficiency input unit 144 No. 1 No. 2 diffused efficiency calculating unit 244 No. 1 No. 3 diffused Efficiency calculation unit 46 No. 1 air magnification calculation unit 145 No. 2 aeration air amount calculation unit 245 No. 3 aeration air amount calculation unit 47 No. 1 DO limiter device 147 No. 2 DO limiter device 247 No. 3 DO limiter device

Claims (5)

In an aeration air volume control device of a sewage treatment plant including an aerobic tank having an aeration device that operates according to an aeration air volume target value, and having a plurality of sewage treatment processes of the same treatment method,
Flow rate control means for controlling the flow rate of sewage flowing into all systems to be equal;
An ammonia meter that measures the ammoniacal nitrogen concentration of the aerobic tank of any one of a plurality of series;
A dissolved oxygen concentration meter for measuring the dissolved oxygen concentration of the aerobic tank of all the series of a plurality of series;
First target value setting means for setting the ammonia nitrogen concentration target value of the treated water;
Based on the dissolved oxygen concentration measured value by the dissolved oxygen concentration meter of the aerobic tank of the series where the ammonia meter is installed, the dissolved oxygen concentration target value of the other aerobic tank of the other series where the ammonia meter is not installed A second target value setting means for setting each;
The aeration apparatus of the aerobic tank in which the ammonia meter is installed calculates an aeration air volume target value that brings the measured value of the ammonia nitrogen concentration close to the ammonia nitrogen concentration target value, and the aerobic device in which the ammonia meter is not installed A controller for calculating an aeration air volume target value that brings the measured value of the dissolved oxygen concentration closer to the dissolved oxygen concentration target value,
An aeration air volume control device for a sewage treatment plant. In an aeration air volume control device of a sewage treatment plant including an aerobic tank having an aeration device that operates according to an aeration air volume target value, and having a plurality of sewage treatment processes of the same treatment method,
Flow rate control means for controlling the flow rate of sewage flowing into all systems to be equal;
An ammonia meter that measures the ammoniacal nitrogen concentration of the aerobic tank of any one of a plurality of series;
Target value setting means for setting the ammonia nitrogen concentration target value of the treated water;
Aeration efficiency input means for inputting the aeration efficiency of the aeration apparatus for each series, and the aerobic tank aeration apparatus of the series where an ammonia meter is installed based on the inputted aeration efficiency, etc. Aeration efficiency ratio calculating means for obtaining the aeration efficiency ratio of each of the aeration devices of the aerobic tank of the series,
An aeration apparatus for the aerobic tank in which an ammonia meter is installed, a controller for calculating an aeration air volume target value for bringing the measured value of the ammonia nitrogen concentration close to the ammonia nitrogen concentration target value;
Aeration air volume calculation means for calculating the aeration air volume target value of the aeration apparatus of the aerobic tank in which the ammonia meter is not installed by multiplying the aeration air volume target value calculated by the controller with an aeration efficiency ratio;
An aeration air volume control device for a sewage treatment plant. In an aeration air volume control device of a sewage treatment plant including an aerobic tank having an aeration device that operates according to an aeration air volume target value, and having a plurality of sewage treatment processes of the same treatment method,
An inflow flow meter that measures the flow rate of sewage flowing into each series;
An ammonia meter that measures the ammoniacal nitrogen concentration of the aerobic tank of any one of a plurality of series;
Target value setting means for setting the ammonia nitrogen concentration target value of the treated water;
Aeration efficiency input means for inputting the aeration efficiency of the aeration apparatus for each series, and the aeration apparatus of the aerobic tank of one series in which an ammonia meter is installed based on the inputted aeration efficiency, Aeration efficiency ratio calculating means for obtaining the aeration efficiency ratio of each of the aeration devices of the aerobic tank of the other series,
An aeration apparatus for the aerobic tank in which an ammonia meter is installed, a controller for calculating an aeration air volume target value for bringing the measured value of the ammonia nitrogen concentration close to the ammonia nitrogen concentration target value;
An air magnification calculating means for calculating the air magnification of the series from the flow rate of sewage flowing into the series including the aerobic tank in which the ammonia meter is installed and the amount of aeration air of the aeration apparatus;
The aeration air volume target value calculated by the controller is multiplied by the air magnification, and the aeration air volume target value obtained by the multiplication, the value obtained by multiplying the input aeration efficiency by the aeration efficiency ratio, and the inflowing sewage An aeration air volume calculating means for calculating an aeration air volume target value of the aeration apparatus of the aerobic tank in which an ammonia meter is not installed, based on the flow measurement value of
An aeration air volume control device for a sewage treatment plant. An inflow flow meter for measuring the total inflow of sewage flowing into the sewage treatment plant,
A total nitrogen meter that measures the total nitrogen concentration of the incoming sewage,
And the first target value setting means or the target value setting means is the ammonia nitrogen concentration target value of the treated water based on both or both of the measured total inflow of sewage and / or the total nitrogen concentration. The aeration air volume control device for a sewage treatment plant according to any one of claims 1 to 3, wherein: A dissolved oxygen concentration meter that measures the dissolved oxygen concentration of all series,
A limiter device for setting the upper and lower limit values of the dissolved oxygen concentration and controlling the aeration air volume so that the measured dissolved oxygen concentration of each series does not deviate from the upper and lower limit values;
An aeration air volume control device for a sewage treatment plant according to any one of claims 1 to 4, characterized by comprising:

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