JPH081184A - Control device of oxidation ditch water treatment apparatus - Google Patents

Abstract

PURPOSE:To obtain a control device of an oxidation ditch water treatment apparatus always well removing a nitrogen component in sewage and well performing solid-liquid separation treatment in a sedimentation basin to always ensure good water quality. CONSTITUTION:When water to be treated is allowed to flow in a ditch 1 to be subjected to activated sludge treatment by the aeration rotor 2 formed in the ditch 1, the concns. of nitrate nitrogen and ammonia nitrogen in water to be treated are respectively measured by concentration meters 100, 101 and the objective value of the number of rotations of the aeration rotor 2 is outputted corresponding to the deviation of the concn. difference between them and the objective value of the concn. difference preset to a setting device 103. The number of rotations of the aeration rotor is regulated according to the objective value of the number of rotations by a driver 3 to perform activated sludge treatment to remove a nitrogen component in water to be treated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an oxidation ditch water treatment device, and more particularly to a control device for efficiently removing nitrogen components in sewage which is a causative substance of eutrophication in a water treatment process. It is a thing.

[0002]

[Prior Art] Oxidation Ditch Water Treatment, as described in "Technical Data of Oxidation Ditch Method" (Japan Sewer Works Technical Development Department / Sewer Works Business Dissemination Association, January 1986) With the law, the sedimentation of general sewage, mainly domestic sewage, and the sewage after screen treatment are treated with activated sludge using an endless water channel (ditch) with a mechanical aeration device as a reaction tank. This is a series of sewage treatment methods that remove suspended solids in the sedimentation pond.

In recent years, the closed water area, which is the source of water supply, is eutrophied and the red tide and musty odorous microorganisms are frequently propagated. Therefore, it is required to remove nitrogen, which is the causative agent, in the lower and waste water. In the oxidation ditch method, an aerobic region where dissolved oxygen exists and an anaerobic region where dissolved oxygen does not exist are formed spatially (in the flow direction) in the ditch, and proceed in an aerobic state with a nitrification reaction and in an anaerobic state. Nitrogen in sewage can be removed in combination with the denitrification reaction.

FIG. 43 is a block diagram showing an example of a conventional oxidation ditch water treatment apparatus. In FIG. 43, 1 is a ditch and 2 is an aeration rotor. Reference numeral 3 is a drive device for the aeration rotor, which is connected to the aeration rotor 2 by a driving force transmission means 3a. 4 is the overflow weir. Reference numeral 13 denotes a drive device for changing the height of the overflow weir 4, which is connected to the overflow weir 4 by a driving force transmission means 13a. 5 is a sedimentation basin, 6 is a pump for discharging excess sludge, and 7 is a pump for returning sludge to the ditch 1. Reference numeral 8 is a dissolved oxygen concentration meter installed at an arbitrary point in the ditch. Further, a is a pipe for introducing the sewage into the ditch 1, b is a pipe for introducing the outflow water from the ditch 1 into the sedimentation basin 5, c is a pipe for discharging the precipitation treated water, and d.
Is a pipe for extracting sludge from the sedimentation basin, e is a pump 6
Is a pipe for discharging the sludge extracted as a surplus sludge, and f is a pipe for circulating the sludge returned by the pump 7 to the ditch 1.

Next, the operation will be described. Sewage is introduced into the ditch 1 via the pipe a. In Ditch 1,
Oxygen required for the treatment is supplied by the aeration rotor 2, the inflowing sewage and the activated sludge in the ditch 1 are mixed and stirred, and a flow velocity is given to the mixed liquid to circulate in the ditch 1. The adjustment of the oxygen supply amount by the aeration rotor 2 is performed by changing the rotation speed or the immersion depth of the aeration rotor 2. The rotation speed of the aeration rotor 2 is changed by operating the drive unit 3, and the immersion depth is changed by operating the drive unit 13 of the overflow weir 4. The dissolved oxygen concentration meter 8 measures the dissolved oxygen concentration in the ditch 1. The operation manager of the water treatment device appropriately adjusts the rotation speed or the immersion depth of the aeration rotor 2 while observing the measured value. If these adjustments are successful and an aerobic region and an anaerobic region are appropriately formed in the ditch 1, nitrogen in the sewage will be removed well.

On the other hand, the mixed liquid treated with activated sludge is piped b.
It is introduced into the settling basin 5 via. In the settling tank 5, solid-liquid separation of the activated sludge mixed liquid is performed. The supernatant water is discharged via the pipe c. The concentrated sludge is drawn out through the pipe d. A part of the sludge is discharged as excess sludge by the pump 6 to the outside of the system through the pipe e, and a part of the sludge is returned to the ditch 1 through the pipe f by the pump 7 as return sludge.

[0007]

As described above, conventionally, the operation manager refers to the measured value of the dissolved oxygen concentration in the ditch and the like, and refers to the mechanical aeration device, for example, the rotation speed and the immersion depth of the aeration rotor. Was being adjusted. However, the flow rate and properties of general sewage, mainly domestic sewage, change significantly, so
There is a problem in that it is difficult to properly form an aerobic state and an anaerobic state spatially in the ditch in accordance with the fluctuation and to always secure good water quality.

Further, when the flow rate into the ditch increases, the flow rate into the sedimentation basin also increases, so that solid-liquid separation of the activated sludge mixture cannot be sufficiently performed, and it is difficult to always ensure good water quality. There was a problem.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to appropriately control the number of revolutions of the aeration rotor of the oxidation ditch water treatment device or the immersion depth or the amount of sludge drawn out. It is an object of the present invention to obtain a control device for an oxidation ditch water treatment device that can always remove nitrogen components well and ensure good water quality. Further, for the purpose of obtaining a control device of an oxidation ditch water treatment device, which can perform a solid-liquid separation treatment favorably by always controlling the flow rate flowing out to a sedimentation basin and always ensure a good water quality. There is.

[0010]

A control device of an oxidation ditch water treatment apparatus according to claim 1 of the present invention measures a nitrate nitrogen concentration in treated water, and measures an ammonia nitrogen concentration in treated water. Means, a controller that outputs the target value of the number of revolutions of the aeration device or the immersion depth according to the deviation between the concentration difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration and the predetermined target value of the concentration difference. , And adjusting means for adjusting the rotation speed or the immersion depth of the aeration device according to the target value of the rotation speed or the immersion depth.

According to a second aspect of the present invention, in the controller of the oxidation ditch water treatment apparatus, the target value of the concentration difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration in the treated water is set to −
It is set in the range of 10 to 10 [mg / liter].

According to a third aspect of the present invention, there is provided a controller for an oxidation ditch water treatment apparatus, which comprises means for measuring the concentration of nitrate nitrogen in treated water, means for measuring the concentration of ammonia nitrogen in treated water, and concentration of nitrate nitrogen. And the concentration ratio of the ammonia nitrogen concentration, and a controller that outputs the target value of the rotation speed or the immersion depth of the aeration device according to the deviation between the predetermined target value of the above-mentioned concentration ratio, and the rotation speed or According to the target value of the immersion depth, the adjusting means is provided for adjusting the rotation speed of the aeration device or the immersion depth.

According to a fourth aspect of the present invention, in the controller of the oxidation ditch water treatment device, the target value of the concentration ratio between the nitrate nitrogen concentration and the ammonia nitrogen concentration in the treated water is 0.1-10. It is set in the range.

According to a fifth aspect of the present invention, there is provided a control device for an oxidation ditch water treatment apparatus, which comprises means for measuring the total nitrogen concentration in the treated water, means for measuring the nitrate nitrogen concentration in the treated water, total nitrogen concentration and nitric acid. Controller for outputting the target value of the rotation speed or the immersion depth of the aeration device according to the deviation between the concentration ratio with the nitrogen concentration and the predetermined target value of the above-mentioned concentration ratio, and the rotation speed or the immersion depth According to the target value of the depth, an adjusting means for adjusting the rotation speed or the immersion depth of the aeration device is provided.

According to a sixth aspect of the present invention, there is provided a control device for an oxidation ditch water treatment apparatus, which comprises means for measuring the total nitrogen concentration in the treated water, means for measuring the ammonia nitrogen concentration in the treated water, total nitrogen concentration and ammonia. Controller for outputting the target value of the rotation speed or the immersion depth of the aeration device according to the deviation between the concentration ratio with the nitrogen concentration and the predetermined target value of the above-mentioned concentration ratio, and the rotation speed or the immersion depth According to the target value of the depth, an adjusting means for adjusting the rotation speed or the immersion depth of the aeration device is provided.

According to a seventh aspect of the present invention, in the controller of the oxidation ditch water treatment device, the target value of the ratio of the concentration of nitrate nitrogen or ammonia nitrogen in the treated water to the total nitrogen concentration is from 1:10. It is set in the range of 9:10.

The control device of the oxidation ditch water treatment device according to claim 8 of the present invention is the dissolution of an arbitrary point in a region ¼ to ½ times the ditch length away from the aeration device installation point in the downflow direction. Means for measuring oxygen concentration, the number of revolutions of the aeration device or the number of revolutions of the aeration device depending on the deviation between the measured value of the dissolved oxygen concentration and the target value of the dissolved oxygen concentration preset to a value near 0 [mg / liter] It is provided with a controller that outputs a target value of the immersion depth, and an adjusting unit that adjusts the rotational speed or the immersion depth of the aeration device according to the target value of the rotational speed or the immersion depth.

According to a ninth aspect of the present invention, there is provided at least one control device for the oxidation ditch water treatment device, which is installed in a range separated by 0 to 1/2 times the ditch length in the downflow direction from the aeration device installation point. Means for measuring dissolved oxygen concentration,
Using the measured value of the dissolved oxygen concentration measured by this dissolved oxygen concentration measuring means, the dissolved oxygen concentration in the ditch is 0 [mg
/ Liter], a calculation means for calculating a point at which a reference value of the dissolved oxygen concentration set in advance to a value in the vicinity thereof is calculated. The calculation value calculated by this calculation means and the ditch length of 1 from the installation point of the aeration device in the downflow direction. Controller that outputs a rotation speed of the aeration device or a target value of the immersion depth according to a deviation from a target value of the point set in advance in a range separated by / 4 to 3/4 times, and the rotation speed. Or according to the target value of immersion depth,
It is provided with an adjusting means for adjusting the rotation speed or the immersion depth of the aeration device.

According to a tenth aspect of the present invention, there is provided a control device for an oxidation ditch water treatment device, according to means for measuring the water quality of the treated water, and the deviation between the measured water quality value and a predetermined water quality target value. A calculator for calculating the target value of the activated sludge microbial concentration, a controller for outputting the target value of the sludge extraction amount according to the deviation between the target value of the activated sludge microbial concentration and the measured value of the activated sludge microbial concentration, and the above. According to the target value of the sludge drawing-out amount, the adjusting means for adjusting the sludge drawing-out amount is provided.

The control device of the oxidation ditch water treatment device according to claim 11 of the present invention uses the measured value of the concentration of activated sludge microorganisms measured at any point in the ditch or the target value of the activated sludge microorganism concentration, A correction means for correcting the target value of the dissolved oxygen concentration is provided.

According to a twelfth aspect of the present invention, in the controller for the oxidation ditch water treatment device, the dissolved sludge microbe concentration is measured based on the measured value of the activated sludge microbe concentration measured at any point in the ditch or the target value of the activated sludge microbe concentration. The correction means is provided to correct the target value at the point where the oxygen concentration reaches the reference value.

According to a thirteenth aspect of the present invention, there is provided a control device for an oxidation ditch water treatment device according to the means for measuring the water quality of the treated water and the deviation between the measured water quality value and a predetermined water quality target value. The controller is provided with a controller for calculating a target value of the amount of sludge drawn out, and an adjusting means for adjusting the amount of sludge drawn out according to the target value of the amount of drawn sludge.

A control device for an oxidation ditch water treatment device according to claim 14 of the present invention is a device for measuring at least one of water temperature, pH and redox potential installed at an arbitrary point in the ditch. A correction means for correcting the target value of the dissolved oxygen concentration from the measured value is provided.

According to a fifteenth aspect of the present invention, a controller for an oxidation ditch water treatment apparatus is a means for measuring at least one of water temperature, pH and redox potential installed at any point in the ditch. A correction means is provided to correct the target value at the point where the reference value of the dissolved oxygen concentration is reached from the measured value.

According to a sixteenth aspect of the present invention, there is provided a control device for an oxidation ditch water treatment apparatus, wherein the means for measuring the inflow load to the ditch, and the reference value of the rotation speed or the immersion depth of the aeration device from the measured value of the inflow load. It is provided with a means for calculating the feedforward amount of the value.

According to a seventeenth aspect of the present invention, in the controller of the oxidation ditch water treatment device, the means for measuring the outflow rate from the ditch, the deviation between the measured outflow rate and the predetermined target value of the outflow rate. The controller includes a controller that outputs a target value of the water level of the ditch in accordance with the above, and an adjusting unit that adjusts the outflow rate according to the target value of the water level.

[0027]

The control device of the oxidation ditch water treatment device according to the first to fourth aspects measures the nitrate nitrogen concentration and the ammonia nitrogen concentration in the treated water, and uses the concentration difference or concentration ratio of both to measure the aeration rotor. The aerobic region and the anaerobic region are appropriately formed in the ditch by adjusting the rotation speed or the immersion depth.

The control device of the oxidation ditch water treatment device according to any one of claims 5 to 7 measures the total nitrogen concentration and the nitrate nitrogen concentration or the ammonia nitrogen concentration in the treated water, and aerates by using the concentration ratio of both. An aerobic region and an anaerobic region are appropriately formed in the ditch by adjusting the rotation speed of the rotor or the immersion depth.

The control device of the oxidation ditch water treatment device according to claim 8 measures the dissolved oxygen concentration in a specific section of the ditch, and adjusts the rotation speed or the immersion depth of the aeration rotor using this measured value. By doing so, the dissolved oxygen concentration at the measurement point is kept constant, and an aerobic region and an anaerobic region are appropriately formed in the ditch.

The control device of the oxidation ditch water treatment device according to claim 9 measures the dissolved oxygen concentration in a specific section of the ditch, and the dissolved oxygen concentration becomes a predetermined reference value using this measured value. An aerobic region and an anaerobic region are appropriately formed in the ditch by estimating the point and adjusting the rotation speed or the immersion depth of the aeration rotor so that this point is always at a predetermined point.

The control device of the oxidation ditch water treatment device according to the tenth and thirteenth aspects measures the treated water quality,
By changing and controlling the target value of the activated sludge microbial concentration or the target value of the sludge extraction amount so that this measured value becomes constant, the aerobic region and the anaerobic region are appropriately formed in the ditch, and at the same time, the water Make sure there is no excess or deficiency in the amount of microorganisms used for treatment.

The control device of the oxidation ditch water treatment device according to claims 11 and 14 measures the factors affecting the microbial activity such as the concentration of activated sludge microorganisms in the ditch, or the water temperature and pH. By using this to correct the control target value of the dissolved oxygen concentration in the specific section in the ditch, the aerobic region and the anaerobic region are always appropriately formed in the ditch.

The control device of the oxidation ditch water treatment device according to the twelfth and fifteenth aspects measures the factors affecting the microbial activity such as the concentration of activated sludge microorganisms in the ditch or the water temperature and pH, and uses the measured values. By correcting the control target value at the point where the dissolved oxygen concentration becomes a predetermined reference value, the aerobic region and the anaerobic region are always properly formed in the ditch.

A control device for an oxidation ditch water treatment device according to a sixteenth aspect measures an inflow load into the ditch and corrects the control reference value of the rotation speed of the aeration rotor or the immersion depth using this measured value. As a result, the aerobic region and the anaerobic region are always properly formed in the ditch.

The control device of the oxidation ditch water treatment device according to claim 17 measures the outflow rate from the ditch and adjusts the ditch water level so as to stabilize the water surface load on the sedimentation pond, thereby Always enable good solid-liquid separation.

[0036]

[Examples] The inventors of the present invention have been able to efficiently remove nitrogen and the like in an oxydendonic water treatment process for many years.
We have repeatedly examined computer simulations based on dynamic models for operation control methods for stable advanced processing. As a result, they discovered several laws useful for controlling and arrived at the present invention. First,
The dynamic model used in the computer simulation will be described below.

The kinetic model of the organic substance removal reaction is represented by the equation 1. This can be found in the literature ("Real-Time Contr
ol of Activated Sludge Pr
ossesses ”(ASCE (EE), 1979)) based on the Stenstrom model.

[0038]

[Equation 1]

Here, r _XS , r _XA , r _XI : generation rate [mg / L · h] Y ₁ , Y ₂ : yield K _S : half-saturation constant [mg / L] K _fS : half-saturation constant XT : MLVSS (active sludge microorganism) concentration [mg / L] XS: Accumulation partial concentration of MLVSS [mg / L] XA: Active partial concentration of MLVSS [mg / L] XI: Inactive partial concentration of MLVSS [mg / L] fs: XS / XT fs ^M : Maximum value of fs S: Organic matter concentration [mg / L] R _T : Transfer coefficient [h ^-1 ] R _XA : Maximum specific growth rate [h ^-1 ] R _XI : Maximum specific death rate [H ^-1 ]. However, L represents liter.

Further, the kinetic model of the nitrification reaction is expressed by equation 2. This is also constructed based on the Stenstrom model described in the above document.

[0041]

[Equation 2]

Here, r _XNS , r _XNB : production rate [mg / L · h] r _SNO3 , r _SNO2 , r _SNH4 : substrate production rate by nitrification reaction [mg / L · h] XNS: nitrosomonas (Nitrosomonas) Concentration [mg / L] XNB: Nitrobacter concentration [mg / L] DO: Dissolved oxygen concentration [mg / L] μ _NS (DO), μ _NB (DO): Specific growth rate by mono (Monod) function ^{_{[h -1] μ NS M,}} μ NB M: maximum specific growth rate _{^{[h -1] D XNS, D}} XNB: specific mortality rate [h ^-1] r _HNH4: matrix production speed by organic removal reaction [mg / L · h] K _DO : Half-saturation constant [mg / L].

Further, the kinetic model of the denitrification reaction is expressed by Equation 3. This is "Water Treatment Engineering" (Gihodo Publishing, 1976).
And references ("Biological Denitri
fication "(Dep. of Sanitar
y EngineeringTechnical Un
iv. of Denmark, 1972)).

R _DNO3 =-(R _HN + R _SN ) XA r _DNH4 = (0.25R _SN + 0.02R _HN Y ₃ ) XA r _DXS = -2.21R _HN XA r _DXA = (R _HN Y ₃ -2.0R _SN ) XA ・ ・ ・ ・ (3)

Here, r _DNO3 , r _DNH4 , r _DXS , r _DXA : production rate by denitrification reaction [Mg / L · h] R _HN : Biosynthetic denitrification rate constant [h ^-1 ] R _SN : Endogenous denitrification rate constant [h ^-1 ] Y ₃ : Yield.

The balance of the dissolved oxygen concentration is expressed by equation 4.

[0047]

(Equation 3)

Here, r _HDO : oxygen consumption rate by removal of organic substances [mg / L · h] r _NDO : oxygen consumption rate by nitrification [mg / L · h] r _DO : oxygen transfer rate [mg / L · h] Y _NS , Y _NB : Yield K _L a: Overall oxygen transfer capacity coefficient [h ^-1 ] DO _s : Saturated dissolved oxygen concentration [mg / L].

The kinetic parameters were set as shown in Table 1.

[0050]

[Table 1]

Further, the mixing in the ditch was approximated by a down-flow tank row model considering the circulating flow as shown in FIG. 1, and the material balance between the tanks was taken.

The apparatus conditions were set as shown in Table 2 with reference to "Development of mechanical aeration apparatus used for oxidation ditch method (Ministry of Construction Technical Evaluation Statement No. 82402)".

[0053]

[Table 2]

The characteristics of the aeration rotor were set as shown in equation 5.

[0055]

[Equation 4]

Here, OC: Oxygen supply rate per rotor 1 [m] [kg-O ₂ / m · h] NN: Oxygen supply efficiency (shaft power) [kg-O ₂ / kWh] K _L a: General Oxygen transfer capacity coefficient [h ^-1 ] q: Power consumption [kW] V _m : Average flow velocity in the pond [m / s] L: Channel length [m] φ: Ratio of input power used for propulsion power P _r : Power input Density [W / m ³ ] V _u : Rotor peripheral speed [m / s] ζ: Channel loss coefficient

2, 3, and 4 show the MLSS concentration of 30.
00 [mg / L], and the aeration rotor immersion depth was changed to 15 [cm], 20 [cm], and 24 [cm], and in (a), (b), and (c) of each figure, The rotation speeds of the aeration rotor are 48 [rpm], 60 [rpm], and 71 [r, respectively.
It is a figure which shows the relationship between the dissolved oxygen concentration distribution in a ditch and the total nitrogen concentration of treated water when the said simulation is performed by changing it with [pm]. The horizontal axis is 6 down the ditch.
As shown in FIG. 1, B, C, D, E, and F are shown in order from the aeration rotor installation point (sewage inflow point) A.
The name is (treated water runoff point). The vertical axis represents the dissolved oxygen concentration. The numbers on the right side of the graph indicate the total nitrogen concentration at point F, the left side in the brackets indicates the ammonia nitrogen concentration, and the right side indicates the nitrate nitrogen concentration.

Similarly, FIG. 5, FIG. 6, and FIG. 7 are diagrams showing the results when a simulation was performed with the MLSS concentration set to 4000 [mg / L], and FIG. 8, FIG. 9, and FIG.
FIG. 5 is a diagram showing a relationship between a dissolved oxygen concentration distribution in a ditch and a total nitrogen concentration in treated water when a simulation is performed with the MLSS concentration set to 5000 [mg / L].

From these figures, it is understood that when the total nitrogen concentration in the treated water is low, the nitrate nitrogen content and the ammonia nitrogen content remain to the same extent. In order to facilitate understanding, FIG. 11 is a diagram in which the horizontal axis represents the difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration at point F, and the vertical axis represents the sum of the two, that is, the total nitrogen concentration. MLSS concentration is 3000 [mg /
L] (solid line), 4000 [mg / L] (dotted line), 500
In any case of 0 [mg / L] (one-dot chain line), when the difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration is 0, the total nitrogen concentration becomes the minimum. From this, the inventors have stated that "the total nitrogen concentration in the treated water can be suppressed to a minimum by setting the nitrate nitrogen concentration and the ammonia nitrogen concentration in the treated water to the same extent". Found the law.

It can also be seen from FIG. 11 that the higher the MLSS concentration, the smaller the total nitrogen concentration in the treated water. From this, the inventors found the second law that "the MLSS concentration must be kept high in order to further remove nitrogen to a high degree".

Applying the first and second laws to the operation of an actual oxidation ditch water treatment process makes it possible to achieve a high degree of treatment of nitrogen in sewage. In order to discover a simpler method that does not require measurement or analysis of nitrogen concentration, the inventors have further described the above FIGS.
Was examined more carefully. According to these figures, MLSS
Regardless of the concentration, when the dissolved oxygen concentration disappears in the vicinity of points C to D, that is, when the aerobic region and the anaerobic region are formed almost equally and nitrification and denitrification occur in a well-balanced manner, It can be seen that the nitrogen concentration is low. It can be said that the optimum point of the boundary between the aerobic region and the anaerobic region depends on the ratio between the nitrification rate and the denitrification rate. To help understanding, when the nitrification rate was set to 10 times the normal value (μ _{NS in} Table 1
^M, 12 simulation results of the mu _NB ^M a to 10-fold), 13, 14, if you set the denitrification rate in the 10 times the normal value (Table 1 R _HN, the R _SN 10 Simulation results of (doubling) are shown in FIGS. 15, 16 and 17.
The way of viewing the figures is the same as in FIGS.

In FIGS. 12, 13 and 14, when the dissolved oxygen concentration disappears near point B, the total nitrogen concentration in the treated water is low. This is because if the nitrification rate is higher than the denitrification rate,
Since the aerobic region may be short, the optimum end position of the aerobic region for the treated water quality is displaced forward from the vicinity of the center of the ditch (aeration rotor side). On the other hand, FIG. 15 and FIG.
6, in FIG. 17, when the dissolved oxygen concentration disappears near point E, the total nitrogen concentration in the treated water is low. This is because, when the denitrification rate is higher than the nitrification rate, the anaerobic region may be short, so that the optimum end position of the aerobic region for the treated water is shifted rearward from the vicinity of the center of the ditch.

The conditions of this simulation are set independently of the actual phenomenon for the purpose of helping understanding, and the nitrification rate and the denitrification rate cannot actually deviate greatly from the literature values. However, water temperature, p
H, redox potential, and the like have some influence on the nitrification rate and denitrification rate, and the degree of the effect differs between the nitrification rate and the denitrification rate. From this, the inventors have stated that "normally, the boundary between the aerobic region and the anaerobic region, which is optimal for nitrogen removal, is near the center of the ditch.
It is affected by changes in factors that affect microbial activity such as H and redox potential. "

Finally, regarding the dissolved oxygen concentration distribution in the ditch, even if the aeration rotor speed and immersion depth are the same, ML
It can be seen from FIGS. 2 to 10 that the gradient of the dissolved oxygen concentration distribution is different when the SS concentration is different. To facilitate understanding, FIG. 18 shows a diagram in which the horizontal axis represents the dissolved oxygen concentration at point A and the vertical axis represents the total nitrogen concentration at point F. From this figure, it is understood that the higher the MLSS concentration, the higher the dissolved oxygen concentration at point A where the total nitrogen concentration becomes the minimum. As described in the derivation of the third law, when the total nitrogen concentration in the treated water is low, the MLS
In all cases of S concentration, the dissolved oxygen concentration disappeared near points C to D. That is, the higher the MLSS concentration, the more rapidly the dissolved oxygen concentration distribution is formed.
From this, the inventors have stated that the higher the MLSS concentration is,
Dissolved oxygen concentration distribution has a steep gradient. "

Example 1. Hereinafter, an embodiment according to claim 1 and claim 2 of the present invention will be described with reference to the drawings. FIG. 19 is a configuration diagram illustrating a control device of the oxidation ditch water treatment device according to the first embodiment. In FIG.
The same reference numerals as in FIG. Also,
Reference numeral 100 is a nitrate nitrogen concentration meter attached to a pipe c for discharging the precipitation treated water, and 101 is an ammonia nitrogen concentration meter. Reference numeral 102 is a controller that outputs a target value of the number of rotations of the aeration rotor 2 according to a deviation between a difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration and a predetermined target value of the concentration difference. 100a is a nitrate nitrogen concentration meter 100, and signal line 101a is an ammonia nitrogen concentration meter 1
01 and the signal line 102a are connected to the driving device 3. Reference numeral 103 denotes a setting device for setting a target value of the density difference, which is connected to the controller 102 via a signal line 103a. The target value set in the setter 103 is in the range of -10 to 10 [mg-N / L], preferably 0 according to the first law.
It is more effective if it is in the vicinity of [mg-N / L]. In addition, [mg-N / L] has shown the unit showing the density | concentration of nitrogen N.

Next, the operation will be described. The nitrate nitrogen concentration in the treated water is measured by the nitrate nitrogen concentration meter 100, and the ammonia nitrogen concentration is measured by the ammonia nitrogen concentration meter 101. The respective measured values are signal lines 100a and 101.
It is transmitted to the controller 102 via a. The controller 102 outputs a target value of the number of revolutions of the aeration rotor 2 according to, for example, Equation 6 according to a deviation between a difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration and a target value of a predetermined concentration difference. .

R _rot = R _rot0 + K _RDN (DN ^* -DN) (6) Here, R _rot : target value of rotation speed of aeration rotor R _rot0 : constant K _RDN : constant DN ^* : (nitrate Target value of nitrogen concentration-ammonia nitrogen concentration) DN: Nitrate nitrogen concentration-Ammonia nitrogen concentration. The target value DN ^* of the density difference required for this calculation is obtained as the output of the setter 103 via the signal line 103a. The output R _rot of the controller 102 is transmitted to the drive device 3 via the signal line 102a, and the rotation speed of the aeration rotor 2 is adjusted.

As a result, if the concentration difference DN is smaller than the target value DN ^* , the rotation speed of the aeration rotor 2 increases, and the aerobic region is extended. On the contrary, if the concentration difference DN is larger than the target value DN ^* , the rotation speed of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, even if the inflow load to the ditch 1 changes, if the rotation speed of the aeration rotor 2 is automatically adjusted so that the concentration of nitrate nitrogen and the concentration of ammonia nitrogen in the treated water remain approximately the same, The end of the area can be adjusted to be near the center of the ditch, and good treated water quality can be stably maintained.

Example 2. Claims 1 and 2 of the present invention
Another embodiment according to the present invention will be described with reference to the drawings. 20: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 2. As shown in FIG. In FIG. 20, reference numeral 104 denotes a controller that outputs a target value of the immersion depth of the aeration rotor 2 according to a deviation between a difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration and a target value of a predetermined concentration difference. Yes, signal line 10
0a is connected to the nitrate nitrogen concentration meter 100, a signal line 101a is connected to the ammonia nitrogen concentration meter 101, and a signal line 103a is connected to a setting device 103 for setting a target value of the concentration difference. Similar to the first embodiment, the target value set in the setter 103 is more effective when set in the range of -10 to 10 [mg-N / L], preferably near 0 [mg-N / L]. 1
Reference numeral 2 is a calculator for calculating a target value of the height of the overflow 4 from the target value of the immersion depth of the aeration rotor 2, which is connected to the controller 104 by a signal line 104a. Reference numeral 13 is a drive device for changing the height of the overflow weir 4, and the drive force transmission means 1
3a is connected to the overflow weir 4, and the signal line 12a is connected to the computing unit 12. Others are the same as in FIG.

Next, the operation will be described. Controller 104
Then, the target value of the immersion depth of the aeration rotor 2 is output according to, for example, Equation 7 according to the deviation between the difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration and the target value of the predetermined concentration difference. D _rot = D _rot0 + K _DDN (DN ^* -DN) (7) Here, D _rot : target value of immersion depth of aeration rotor D _rot0 : constant K _DDN : constant. The measured value of the nitrate nitrogen concentration required for this calculation is output as the output of the nitrate nitrogen concentration meter 100 via the signal line 100a, and the measured value of the ammonia nitrogen concentration is output as the output of the ammonia nitrogen concentration meter 101 as the signal line 101a. Obtained through. The target value DN ^* of the density difference is obtained as an output of the setter 103 via the signal line 103a. Controller 1
The output D _rot of 04 is supplied to the arithmetic unit 12 via the signal line 104a.
Conveyed to. The calculator 12 calculates a target value of the height of the overflow weir 4 from the target value D _rot of the immersion depth of the aeration rotor 2 according to, for example, Expression 8. H = H ₀ + D _rot (8) Here, H: target value of height of overflow weir H ₀ : constant. The output H of the calculator 12 is transmitted to the drive device 13 via the signal line 12a, and the immersion depth of the aeration rotor 2 is adjusted.

As a result, if the concentration difference DN is smaller than the target value DN ^* , the immersion depth of the aeration rotor 2 is increased and the aerobic region is extended. On the contrary, if the concentration difference DN is larger than the target value DN ^* , the immersion depth of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, since the immersion depth of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is near the center of the ditch even if the inflow load to the ditch 1 changes, good treated water quality is stably maintained. Will be able to.

Note that FIG. 20 shows an example in which the target value D _rot of the immersion depth, which is the output of the controller 104, is calculated by the calculator 12 into the target value H of the height of the overflow 4; Also, even if the controller 104 performs the calculation of the equation 8 at one time and the calculator 12 is omitted, the same effect can be obtained.

Example 3. In Examples 1 and 2 described above, the ammonia nitrogen concentration was reduced from the nitrate nitrogen concentration, but the same effect can be obtained by reducing the nitrate nitrogen concentration from the ammonia nitrogen concentration.

Example 4. Claims 3 and 4 of the present invention
An embodiment according to the present invention will be described with reference to the drawings. 21: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 4. FIG. In FIG. 21, reference numeral 105 is an adjustment for outputting the target value of the rotation speed of the aeration rotor 2 in accordance with the deviation between the concentration ratio of the nitrate nitrogen concentration and the ammonia nitrogen concentration and the target value of the predetermined concentration ratio. The signal line 100a is a nitrate nitrogen concentration meter 100, and the signal line 101a.
The ammonia nitrogen concentration meter 101 is connected to the driving device 3 via a signal line 105a. Reference numeral 106 denotes a setting device for setting a target value of the density ratio, which is connected to the controller 105 via a signal line 106a. According to the first law, the target value set in the setter 106 is more effective if it is in the range of 0.1 to 10, and preferably in the vicinity of 1. Others are the same as in FIG.

Next, the operation will be described. Controller 10
In 5, the target value of the number of revolutions of the aeration rotor 2 is output according to, for example, Expression 9 according to the deviation between the concentration ratio of the nitrate nitrogen concentration and the ammonia nitrogen concentration and the target value of the predetermined concentration ratio. . R _rot = R _rot0 + K _RRN1 (RN ₁ ^* _{-RN 1} ) (9) where, K _RRN1 : constant RN ₁ ^* : target value of (nitrate nitrogen concentration / ammonia nitrogen concentration) RN ₁ : nitric acid It is the nitrogen concentration / ammonia nitrogen concentration. The measured value of the nitrate nitrogen concentration required for this calculation is output as the output of the nitrate nitrogen concentration meter 100 via the signal line 100a, and the measured value of the ammonia nitrogen concentration is output as the output of the ammonia nitrogen concentration meter 101 as the signal line 101a. Obtained through. The target value RN ₁ ^* of the density ratio is obtained as an output of the setter 106 via the signal line 106. Controller 10
The output R _rot of _No. 5 is transmitted to the drive device 3 via the signal line 105a, and the rotation speed of the aeration rotor 2 is adjusted.

As a result, the concentration ratio RN ₁ is set to the target value RN ₁ ^*.
If it is smaller than this, the number of revolutions of the aeration rotor 2 increases, and the aerobic region is extended. Conversely, the concentration ratio RN ₁ is the target value RN ₁ ^*
If it is larger than this, the number of rotations of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, the rotational speed of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is near the center of the ditch even if the inflow load to the ditch 1 changes, so that good treated water quality can be stably maintained. Will be able to.

Example 5. Claims 3 and 4 of the present invention
Another embodiment according to the present invention will be described with reference to the drawings. 22: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 5. FIG. In FIG. 22, 107 is a controller that outputs the target value of the immersion depth of the aeration rotor 2 according to the deviation between the ratio of the nitrate nitrogen concentration and the ammonia nitrogen concentration and the target value of the predetermined concentration ratio. Yes, signal line 10
0a is connected to the nitrate nitrogen concentration meter 100, a signal line 101a is connected to the ammonia nitrogen concentration meter 101, and a signal line 106a is connected to a setting device 106 for setting a target value of the concentration difference. Similar to the fourth embodiment, the target value set in the setting device 106 is more effective when it is set in the range of 0.1 to 10, preferably around 1. The controller 107 is also connected by a signal line 107a to a calculator 12 for calculating a target value of the height of the overflow 4 from the target value of the immersion depth of the aeration rotor 2. Others are the same as in FIG.

Next, the operation will be described. Controller 107
Then, the target value of the immersion depth of the aeration rotor 2 is output according to, for example, Equation 10 in accordance with the deviation between the concentration ratio of the nitrate nitrogen concentration and the ammonia nitrogen concentration and the target value of the predetermined concentration ratio. . D _rot = D _rot0 + K _DRN1 (RN ₁ ^* _{-RN 1} ) (10) Here, K _DRN1 : is a constant. The measured value of the nitrate nitrogen concentration required for this calculation is output as the output of the nitrate nitrogen concentration meter 100 via the signal line 100a, and the measured value of the ammonia nitrogen concentration is output as the output of the ammonia nitrogen concentration meter 101 as the signal line 101a. Obtained through. The target value RN ₁ ^* of the density ratio is obtained as an output of the setter 106 via the signal line 106 a. Controller 1
The output D _rot of 07 is the arithmetic unit 12 via the signal line 107a.
Conveyed to. Thereafter, as in the second embodiment, the height of the overflow 4 is adjusted to adjust the immersion depth of the aeration rotor 2.

As a result, the concentration ratio RN ₁ becomes the target value RN ₁ ^*.
If smaller than this, the immersion depth of the aeration rotor 2 increases,
Extend the aerobic region. Conversely, the concentration ratio RN ₁ is the target value RN
If it is larger than ₁ ^*, the immersion depth of the aeration rotor 2 is reduced and the aerobic region is shortened. That is, since the immersion depth of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is near the center of the ditch even if the inflow load to the ditch 1 changes, good treated water quality is stably maintained. Will be able to.

Note that FIG. 22 shows an example in which the target value of the immersion depth, which is the output of the controller 107, is calculated by the calculator 12 as the target value of the height of the overflow 4, but the calculation is adjusted at one time. Total 1
Even if the calculator 12 is omitted, the same effect can be obtained.

Example 6. In the above Examples 4 and 5, the nitrate nitrogen concentration was divided by the ammonia nitrogen concentration, but the same effect can be obtained by dividing the ammonia nitrogen concentration by the nitrate nitrogen concentration.

Example 7. Claims 5 and 7 of the present invention
An embodiment according to the present invention will be described with reference to the drawings. 23: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 7. FIG. In FIG. 23, 25 is a total nitrogen concentration meter attached to a pipe c for discharging the precipitation-treated water. Reference numeral 108 denotes a controller that outputs a target value of the rotation speed of the aeration rotor 2 according to a deviation between a concentration ratio of the nitrate nitrogen concentration to the total nitrogen concentration and a predetermined target value of the concentration ratio. The total nitrogen concentration meter 25 on the line 25a,
The signal line 100a and the nitrate nitrogen concentration meter 100, and the signal line 1
It is connected to the driving device 3 at 08a. Reference numeral 109 denotes a setting device for setting a target value of the density ratio,
It is connected to the controller 108 at a. The target value set in the setter 109 is the total nitrogen concentration obtained by adding the nitrate nitrogen concentration and the ammonia nitrogen concentration. Further, as shown in the first law, the nitrate nitrogen concentration and the ammonia nitrogen concentration are set. Since the total nitrogen concentration in the treated water can be suppressed to a minimum when the concentrations are almost equal, the ratio between the nitrate nitrogen concentration and the total nitrogen concentration is in the range of 1:10 to 9:10, and the optimum ratio is 1 : It is better to set it to 2. That is, the concentration ratio of the nitrate nitrogen concentration to the total nitrogen concentration was 0.
It is effective to set it in the range of 1 to 0.9, preferably 0.25 to 0.75, and the optimum value near 0.5. Others are the same as in FIG.

Next, the operation will be described. Controller 10
In 8, the target value of the rotation speed of the aeration rotor 2 is output according to, for example, Expression 11 according to the deviation between the concentration ratio of the nitrate nitrogen concentration and the total nitrogen concentration and the target value of the predetermined concentration ratio. R _rot = R _rot0 + K _RRN2 (RN ₂ ^* _{-RN 2} ) (11) where, K _RRN2 : constant RN ₂ ^* : (nitrate nitrogen concentration / total nitrogen concentration) target value RN ₂ : nitrate Nitrogen concentration / total nitrogen concentration. The measured value of the nitrate nitrogen concentration necessary for this calculation is output as the output of the nitrate nitrogen concentration meter 100 via the signal line 100a, and the measured value of the total nitrogen concentration is output as the output of the total nitrogen concentration meter 25 via the signal line 25a. Obtained. The target value RN ₂ ^* of the density ratio is obtained as an output of the setter 109 via the signal line 109. The output R _rot of the controller 108 is the signal line 1
It is transmitted to the drive device 3 via 08a, and the rotation speed of the aeration rotor 2 is adjusted.

As a result, the concentration ratio RN ₂ becomes the target value RN ₂ ^*.
If it is smaller than this, the number of revolutions of the aeration rotor 2 increases, and the aerobic region is extended. Conversely, the concentration ratio RN ₂ is the target value RN ₂ ^*
If it is larger than this, the number of rotations of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, the rotational speed of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is near the center of the ditch even if the inflow load to the ditch 1 changes, so that good treated water quality can be stably maintained. Will be able to.

Example 8. Claims 5 and 7 of the present invention
Another embodiment according to the present invention will be described with reference to the drawings. 24: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 8. FIG. In FIG. 24, 110 is a controller that outputs the target value of the immersion depth of the aeration rotor 2 according to the deviation between the concentration ratio of the nitrate nitrogen concentration to the total nitrogen concentration and the target value of the predetermined concentration ratio. Yes, signal line 25
The total nitrogen concentration meter 25 is connected with a, the nitrate nitrogen concentration meter 100 is connected with the signal line 100a, and the setting device 109 for setting the target value of the concentration difference is connected with the signal line 109a. Example 7
Similarly to, the target value set in the setter 109 is 0.1 to
It is effective that the range is 0.9, preferably 0.25 to 0.75, and the optimum value is near 0.5. Controller 11
0 is also connected to a calculator 12 that calculates a target value of the height of the overflow 4 from the target value of the immersion depth of the aeration rotor 2. Others are the same as in FIG.

Next, the operation will be described. Controller 110
Then, the target value of the immersion depth of the aeration rotor 2 is output according to, for example, Equation 12 in accordance with the deviation between the concentration ratio of the nitrate nitrogen concentration and the total nitrogen concentration and the target value of the predetermined concentration ratio. D _rot = D _rot0 + K _DRN2 (RN ₂ ^* _{-RN 2} ) (12) Here, K _DRN2 is a constant. The total nitrogen concentration measured value required for this calculation is output as the total nitrogen concentration meter 25 via the signal line 25a, and the nitrate nitrogen concentration measured value is output as the nitrate nitrogen concentration meter 100 via the signal line 100a. Obtained. The target value RN ₂ ^* of the concentration ratio is output from the setter 109 as a signal line 109 a.
Obtained through. The output D _rot of the controller 110 is transmitted to the calculator 12 via the signal line 110a.

As a result, the concentration ratio RN ₂ becomes the target value RN ₂ ^*.
If smaller than this, the immersion depth of the aeration rotor 2 increases,
Extend the aerobic region. Conversely, the concentration ratio RN ₂ is the target value RN
If it is larger than ₂ ^*, the immersion depth of the aeration rotor 2 is reduced and the aerobic region is shortened. That is, since the immersion depth of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is near the center of the ditch even if the inflow load to the ditch 1 changes, good treated water quality is stably maintained. There is an effect that can be.

Note that FIG. 24 shows an example in which the target value D _rot of the immersion depth, which is the output of the controller 110, is calculated by the calculator 12 as the target value of the height of the overflow 4; The same effect can be obtained even if the controller 110 is used and the arithmetic unit 12 is omitted.

Example 9. In Examples 7 and 8 above, the nitrate nitrogen concentration was divided by the total nitrogen concentration, but the same effect can be obtained by dividing the total nitrogen concentration by the nitrate nitrogen concentration. However, it is effective that the target value of the concentration ratio at this time is in the range of 1 to 10, preferably 1.3 to 4.0, and the optimum value is close to 2.

Example 10. An embodiment according to claim 6 and claim 7 of the present invention will be described with reference to the drawings. 25: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 10. FIG. In FIG. 25, 111 is the concentration ratio of the ammonia nitrogen concentration to the total nitrogen concentration,
It is a controller that outputs a target value of the rotation speed of the aeration rotor 2 according to a deviation from a target value of a predetermined concentration ratio. The densitometer 101 and the signal line 111a are connected to the driving device 3. Reference numeral 112 denotes a setter for setting a target value of the density ratio, which is connected to the controller 11 via a signal line 112a.
It is connected to 1. The target value set in the setter 112 is the total nitrogen concentration obtained by adding the nitrate nitrogen concentration and the ammonia nitrogen concentration, as described in Example 7, and as shown in the first law. Since the total nitrogen concentration in the treated water can be suppressed to a minimum when the nitrate nitrogen concentration and the ammonia nitrogen concentration are almost equal, the ratio of the ammonia nitrogen concentration to the total nitrogen concentration is from 1:10 to 9:10.
It is preferable that the range is set to be 1: 2 as an optimum ratio. That is, it is effective that the concentration ratio of the ammonia nitrogen concentration to the total nitrogen concentration is in the range of 0.1 to 0.9, preferably 0.25 to 0.75, and the optimum value is near 0.5. . Others are the same as in FIG.

Next, the operation will be described. Controller 11
In 1, the target value of the rotation speed of the aeration rotor 2 is output according to, for example, Expression 13 according to the deviation between the concentration ratio of the ammonia nitrogen concentration and the total nitrogen concentration and the target value of the predetermined concentration ratio. _{R rot = R rot0 -K RRN3 (} RN 3 * -RN 3) ··· (13) Here, K _RRN3: Constant RN ₃ ^* :( ammonium nitrogen concentration / target RN ₃ total nitrogen concentration): Ammonia Soluble nitrogen concentration / total nitrogen concentration. The measured value of the ammonia nitrogen concentration necessary for this calculation is output from the ammonia nitrogen concentration meter 101 as a signal line 1.
01a, and the measured value of the total nitrogen concentration is obtained as an output of the total nitrogen concentration meter 25 via the signal line 25a. The target value RN ₃ ^* of the density ratio is obtained as an output of the setter 112 via the signal line 112. Output of controller 111 R _rot
Is transmitted to the drive device 3 via the signal line 111a, and the rotation speed of the aeration rotor 2 is adjusted.

As a result, the concentration ratio RN ₃ becomes the target value RN ₃ ^*.
If it is larger than this, the number of revolutions of the aeration rotor 2 increases, and the aerobic region is extended. Conversely, the concentration ratio RN ₃ is the target value RN ₃ ^*
If it is smaller than this, the number of rotations of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, the rotational speed of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is near the center of the ditch even if the inflow load to the ditch 1 changes, so that good treated water quality can be stably maintained. Will be able to.

Example 11. Another embodiment according to claims 6 and 7 of the present invention will be described with reference to the drawings. 26: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 11. FIG. In FIG. 26, 113
Is a controller that outputs the target value of the immersion depth of the aeration rotor 2 according to the deviation between the concentration ratio of the ammonia nitrogen concentration to the total nitrogen concentration and the target value of the predetermined concentration ratio. Total nitrogen concentration meter 25 and signal line 101
a, the ammonia nitrogen concentration meter 101 and the signal line 112a
Is connected to the setting device 112 for setting the target value of the density difference. The controller 113 is also connected to a calculator 12 that calculates a target value for the height of the overflow 4 from the target value for the immersion depth of the aeration rotor 2. Others are the same as those in FIG.

Next, the operation will be described. Controller 113
Then, the target value of the immersion depth of the aeration rotor 2 is output according to, for example, Expression 14 according to the deviation between the concentration ratio of the ammonia nitrogen concentration and the total nitrogen concentration and the target value of the predetermined concentration ratio. D _rot = D _rot0 −K _DRN3 (RN ₃ ^* _{-RN 3} ) ... (14) Here, K _DRN3 is a constant. The total nitrogen concentration measurement value necessary for this calculation is obtained as the output of the total nitrogen concentration meter 25, and the ammonia nitrogen concentration measurement value is obtained as the output of the ammonia nitrogen concentration meter 25 via the signal line 25a. The target value RN ₃ ^* of the density ratio is obtained as an output of the setter 112 via the signal line 112a. The output D _rot of the controller 113 is transmitted to the calculator 12 via the signal line 113a.

As a result, the concentration ratio RN ₃ becomes the target value RN ₃ ^*.
If it is larger than this, the immersion depth of the aeration rotor 2 increases,
Extend the aerobic region. Conversely, the concentration ratio RN ₃ is the target value RN
If it is smaller than ₃ ^*, the immersion depth of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, since the immersion depth of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is near the center of the ditch even if the inflow load to the ditch 1 changes, good treated water quality is stably maintained. Will be able to.

Although the target value of the immersion depth, which is the output of the controller 113, is calculated by the calculator 12 as the target value of the height of the overflow 4 in FIG. 26, the calculation is adjusted at one time. Total 1
The same effect can be obtained even if the calculator 12 is omitted.

Example 12. In the above Examples 10 and 11,
Although the ammonia nitrogen concentration is divided by the total nitrogen concentration, the same effect can be obtained by dividing the total nitrogen concentration by the ammonia nitrogen concentration. However, it is effective that the target value of the concentration ratio at this time is in the range of 1 to 10, preferably 1.3 to 4.0, and the optimum value is near 2 as in the ninth embodiment.

Example 13 An embodiment according to claim 8 of the present invention will be described with reference to the drawings. 27: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 13. FIG. In FIG. 27, reference numeral 8 denotes a dissolved oxygen concentration meter, which is a ditch 1 whose starting point is the installation point of the aeration rotor 2.
The dissolved oxygen concentration is measured in the vicinity of the center, preferably at a point separated by 1/4 to 1/2 times the Ditch length from the installation point of the aeration rotor 2 in the downflow direction. As shown in the third law, the boundary between the aerobic region and the anaerobic region, which is optimum for nitrogen removal, is near the center of the ditch.
By measuring the dissolved oxygen concentration slightly forward (aeration rotor 2 side), it is possible to reliably detect that the end of the aerobic region is near the center of the ditch 1. If the dissolved oxygen concentration near the aeration rotor 2 was measured,
It is difficult to estimate the end position of the aerobic region in the oxidation ditch, where the inflow load changes greatly and the dissolved oxygen concentration distribution is unstable, and it is detected that the aerobic region is too short behind the center of the ditch 1. Since it cannot be done, from the installation point of the aeration rotor 2 to 1/4 of the ditch length in the downflow direction
It is most appropriate to measure the dissolved oxygen concentration at a point separated by 1/2 times.

Reference numeral 9 is a controller that outputs a target value of the number of revolutions of the aeration rotor 2 according to a deviation between a measured value of the dissolved oxygen concentration and a predetermined target value of the dissolved oxygen concentration.
The dissolved oxygen concentration meter 8 is connected to a and the driving device 3 is connected to the signal line 9a. Reference numeral 10 denotes a setting device for setting a target value of the dissolved oxygen concentration, which is connected to the controller 9 via a signal line 10a. Since the target value set in the setter 10 is the dissolved oxygen concentration slightly ahead of the end of the aerobic region, it is 0 [m
It is suitable to set the value in the vicinity of g / L], preferably 0 to 1 [mg / L]. Others are the same as in FIG.

Next, the operation will be described. 1/4 to 1/2 of the ditch length in the downflow direction from the installation point of the aeration rotor 2
The dissolved oxygen concentration at the point separated by twice is measured by the dissolved oxygen concentration meter 8. The measured value of the dissolved oxygen concentration is transmitted to the controller 9 via the signal line 8a. The controller 9 outputs the target value of the number of revolutions of the aeration rotor 2 according to, for example, Expression 15 according to the deviation between the measured value of the dissolved oxygen concentration and the predetermined target value of the dissolved oxygen concentration. R _rot = R _rot0 + K _RDO (DO ^* -DO) (15) Here, K _RDO : constant DO ^* : target value of dissolved oxygen concentration DO: measured value of dissolved oxygen concentration. Target value DO ^{* of} dissolved oxygen concentration required for this calculation
Is obtained as an output of the setter 10 via the signal line 10a. The output R _rot of the controller 9 is transmitted to the drive device 3 via the signal line 9a, and the rotation speed of the aeration rotor 2 is adjusted.

As a result, if the measured value DO of the dissolved oxygen concentration is smaller than the target value DO ^* , the rotation speed of the aeration rotor 2 increases and the aerobic region is extended. On the contrary, if the measured value DO of the dissolved oxygen concentration is larger than the target value DO ^* , the rotation speed of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, even if the inflow load to the ditch 1 changes, the rotation speed of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is near the center of the ditch, so that the nitrogen concentration is not measured or analyzed. In addition, it is possible to stably maintain good treated water quality.

Example 14. Another embodiment according to claim 8 of the present invention will be described with reference to the drawings. 28: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 14. FIG. In FIG. 28, 11 is the aeration rotor 2
The measured value of the dissolved oxygen concentration at a point separated by 1/4 to 1/2 times the ditch length from the installation point in the downflow direction and 0 [m
g / L] is a controller that outputs the target value of the immersion depth of the aeration rotor 2 according to the deviation from the target value of the dissolved oxygen concentration set in the vicinity of the dissolved oxygen concentration meter 8 via the signal line 8a. The signal line 10a is connected to the setter 10 for setting the target value of the dissolved oxygen concentration. Reference numeral 12 is a calculator for calculating the target value of the height of the overflow 4 from the target value of the immersion depth of the aeration rotor 2, and is connected to the controller 11 by a signal line 11a. Reference numeral 13 is a drive device for changing the height of the overflow weir 4, and the driving force transmitting means 13a is used for the overflow weir 4 and the signal line 1.
It is connected to the calculator 12 at 2a. Others are the same as in FIG. 27.

Next, the operation will be described. The controller 11 outputs the target value of the immersion depth of the aeration rotor 2 according to, for example, Expression 16 according to the deviation between the measured value of the dissolved oxygen concentration and the predetermined target value of the dissolved oxygen concentration. _{D rot = D rot0 + K DDO} (DO * -DO) ··· (16) Here, K _DDO: is a constant. The measured value DO of the dissolved oxygen concentration necessary for this calculation is output from the dissolved oxygen concentration meter 8 via the signal line 8a, and the target value DO ^* of the dissolved oxygen concentration is output from the setter 10 via the signal line 10a. can get. Output D of controller 11
_{The rot} is transmitted to the arithmetic unit 12 via the signal line 11a.

The output of the computing unit 12 is transmitted to the drive unit 13 via the signal line 12a, and the rotation speed of the aeration rotor 2 is adjusted.

As a result, if the measured value DO of the dissolved oxygen concentration is smaller than the target value DO ^* , the immersion depth of the aeration rotor 2 increases and the aerobic region is extended. On the contrary, if the measured value DO of the dissolved oxygen concentration is larger than the target value DO ^* , the immersion depth of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, since the immersion depth of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is located near the center of the ditch even if the inflow load to the ditch 1 is changed, the nitrogen concentration is not measured or analyzed. In addition, it is possible to stably maintain good treated water quality.

Although FIG. 28 shows an example in which the target value of the immersion depth, which is the output of the controller 11, is calculated to the target value of the height of the overflow 4 by the calculator 12, the calculation is adjusted at one time. 11 in total
The same effect can be obtained even if the arithmetic unit 12 is omitted.

Example 15. An embodiment according to claim 9 of the present invention will be described with reference to the drawings. 29: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 15. FIG. In FIG. 29, 14 is a calculator for calculating the point at which the dissolved oxygen concentration in the ditch 1 reaches a predetermined reference value of the dissolved oxygen concentration from the measured value of the dissolved oxygen concentration and the rotation speed of the aeration rotor 2, and The line 8a is connected to the dissolved oxygen concentration meter 8 and the signal line 2a is connected to the aeration rotor 2. The dissolved oxygen concentration meter 8 is located in front of the vicinity of the center of the ditch 1, that is, in the range up to the vicinity of the center of the ditch with the aeration rotor installation point as the starting point, and preferably from the installation point of the aeration rotor 2 to the ditch length 0 to Install in the range up to 1/2 times away. The purpose is to calculate the dissolved oxygen concentration distribution starting from the value measured by the dissolved oxygen concentration meter 8 and adjust the rotation speed of the aeration rotor 2 so that the end of the aerobic region is near the center of the ditch 1. That's why. Reference numeral 15 is a setting device for setting a reference value of the dissolved oxygen concentration, which is connected to the calculator 14 by a signal line 15a. Since the reference value set in the setter 15 is the dissolved oxygen concentration indicating the end of the aerobic region, it is appropriate to select a value near 0 [mg / L], preferably 0 to 1 [mg / L]. Is. 16 outputs the target value of the rotation speed of the aeration rotor 2 according to the deviation between the calculated value (calculation point) at the point where the dissolved oxygen concentration in the ditch 1 reaches the reference value and the target value (target point) at the point. The controller is a signal line 14a, and is connected to the calculator 14 and a signal line 16a to the drive device 3 of the aeration rotor 2. Reference numeral 17 denotes a setter for setting a target value at the point, which is connected to the controller 16 via a signal line 17a. Since the target value set in the setter 17 is preferably near the center of the ditch 1 according to the first law, 1/4 to 3 / of the ditch length from the installation point of the aeration rotor 2 to the downflow direction.
It is appropriate to select from a range up to four times as far apart. Others are the same as in FIG. 27.

Next, the operation will be described. Calculator 14
Then, for example, the distance in the flow-down direction from the installation point of the dissolved oxygen concentration meter 8 at the point where the dissolved oxygen concentration in the ditch 1 reaches a predetermined reference value of the dissolved oxygen concentration is calculated according to Equation 17, for example. x = (DO-DO ^** ) / _Rr * V ( _Rrot ) ... (17) Here, x: The point where the dissolved oxygen concentration in the ditch 1 reaches a predetermined reference value of the dissolved oxygen concentration. Of the dissolved oxygen concentration meter 8 in the downflow direction DO: Measured value of dissolved oxygen concentration DO ^** : Reference value of dissolved oxygen concentration R _r, which is predetermined to a value near 0 [mg / L]: Dissolved oxygen consumption rate V (R _rot ): Circulation flow rate of the mixed solution in the ditch 1 obtained from the rotation speed R _rot of the aeration rotor 2. The measured value DO of the dissolved oxygen concentration required for this calculation is output from the dissolved oxygen concentration meter 8 via the signal line 8a, and the rotational speed R _rot of the aeration rotor 2 is output from the aeration rotor 2 via the signal line 2a. can get. The reference value DO ^** of the dissolved oxygen concentration is obtained as the output of the setter 15 via the signal line 15a. The calculation result x is transmitted to the controller 16 via the signal line 14a. The circulation flow velocity V (R _rot ) of the mixed liquid in the ditch 1 may be directly measured by using a flow velocity meter without _{obtaining it} from the rotation speed R _rot of the aeration rotor 2. Controller 16
Then, for example, the target value of the rotation speed of the aeration rotor 2 is output according to the deviation between the calculated value x at the point where the dissolved oxygen concentration in the ditch 1 reaches the reference value and the target value at the point according to Expression 18. R _rot = R _rot0 + K _Rx (x ^* −x) (18) where K _Rx : constant x ^* : the point where the dissolved oxygen concentration in the ditch 1 reaches a predetermined reference value of the dissolved oxygen concentration. , The target value of the distance in the downflow direction from the installation point of the dissolved oxygen concentration meter 8. The target value x ^* at the point where the dissolved oxygen concentration in the ditch 1 required for this calculation reaches the reference value is obtained as the output of the setter 17 via the signal line 17a. The output R _rot of the controller 16 is transmitted to the drive device 3 via the signal line 16a, and the rotation speed of the aeration rotor 2 is adjusted.

As a result, if the calculated value x at the point where the dissolved oxygen concentration reaches the reference value is smaller than the target value x ^* , the rotation speed of the aeration rotor 2 increases and the aerobic region is extended. On the contrary, if the calculated value x at the point where the dissolved oxygen concentration reaches the reference value is larger than the target value x ^* , the rotation speed of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, since the rotation speed of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region is near the center of the ditch even if the inflow load to the ditch 1 changes, without measuring or analyzing the nitrogen concentration. This has the effect of being able to stably maintain good treated water quality.

Example 16. Another embodiment according to claim 9 of the present invention will be described with reference to the drawings. 30: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 16. FIG. In FIG. 30, 8 and 18 are 0 to 1 / l of the ditch length from the installation point of the aeration rotor 2 in the downflow direction.
It is two dissolved oxygen concentration meters installed in a range up to a distance of two times. Reference numeral 19 is a computing unit that computes a point where the dissolved oxygen concentration in the ditch 1 reaches a reference value of the dissolved oxygen concentration preset to a value near 0 [mg / L] from the measured values of the dissolved oxygen concentrations 8 and 18, The signal line 8a is connected to the dissolved oxygen concentration meter 8, the signal line 18a is connected to the dissolved oxygen concentration meter 18, and the signal line 15a is connected to the setter 15 for setting the reference value of the dissolved oxygen concentration. The calculator 19 is also connected to the controller 16 that outputs the rotation speed of the aeration rotor 2 via a signal line 19a. Others are the same as in FIG.

Next, the operation will be described. Calculator 19
Then, for example, the distance in the downflow direction from the installation point of the dissolved oxygen concentration meter 8 at the point where the dissolved oxygen concentration in the ditch 1 reaches a predetermined reference value of the dissolved oxygen concentration is calculated according to Equation 19, for example. x = L × (DO1-DO ^** ) / (DO1-DO2) (19) Here, L: Distance between the dissolved oxygen concentration meter 8 and the dissolved oxygen concentration meter 18 DO1: By the dissolved oxygen concentration meter 8 Measured value DO2: Measured value by the dissolved oxygen concentration meter 18. Measured value DO of dissolved oxygen concentration required for this calculation
1, DO2 is a dissolved oxygen concentration meter 8 and a dissolved oxygen concentration meter 1
8 is obtained via the signal line 8a and the signal line 18a. The reference value DO ^** of the dissolved oxygen concentration is obtained as the output of the setter 15 via the signal line 15a. Further, the calculation result x is transmitted to the controller 16 via the signal line 19a,
Thereafter, the rotation speed of the aeration rotor 2 is adjusted in the same manner as in the fifteenth embodiment.

In addition to the effects of the fifteenth embodiment, in this embodiment, the position of the end of the aerobic region is directly calculated from the distribution of the dissolved oxygen concentration, so the rotational speed of the aeration rotor 2 should be adjusted more precisely. There is an effect that can be.

Example 17 Still another embodiment according to claim 9 of the present invention will be described with reference to the drawings. FIG. 31 shows the first embodiment
It is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on 7. In FIG. 31, 20 indicates that the dissolved oxygen concentration in the ditch 1 calculated by the calculator 14 is 0 [m
[g / L] The calculated value at a point that reaches a preset reference value in the vicinity of the value and a point that is separated from the installation point of the aeration rotor 2 in the ditch 1 by 1/4 to 3/4 times the ditch length in the downflow direction. Is a controller that outputs the target value of the immersion depth of the aeration rotor 2 according to the deviation from the target value of the point preset in the range up to, and is connected to the calculator 14 by the signal line 14a. Like the fifteenth embodiment, the calculator 14 calculates the point where the dissolved oxygen concentration in the ditch 1 reaches the reference value from the measured value of the dissolved oxygen concentration meter 8 and the rotation speed of the aeration rotor 2. The controller 20 calculates the target value of the height of the overflow weir 4 from the target value of the immersion depth of the aeration rotor 2 using the setter 17 for setting the target value of the point concerned with the signal line 17a and the target value of the immersion depth of the aeration rotor 2 with the signal line 20a. It is also connected to the arithmetic unit 12 for performing. Others are the same as in FIG.

Next, the operation will be described. Controller 20
Then, the target value of the immersion depth of the aeration rotor 2 is output according to, for example, Expression 20, according to the deviation between the calculated value at the point where the dissolved oxygen concentration in the ditch 1 reaches the reference value and the target value at the point. D _rot = D _rot0 + K _Dx (x ^* −x) (20) Here, K _Dx is a constant. The calculated value x at the point where the dissolved oxygen concentration in the ditch 1 required for this calculation reaches the reference value is the output of the calculator 14 via the signal line 14a, and the target value x ^* at that point is the output of the setter 17. It is obtained via the signal line 17.
The calculation result D _rot is transmitted to the calculator 12 via the signal line 20a.

As a result, if the calculated value x at the point where the dissolved oxygen concentration reaches the reference value is smaller than the target value x ^* , the immersion depth of the aeration rotor 2 increases and the aerobic region is extended.
On the contrary, if the calculated value x at the point where the dissolved oxygen concentration reaches the reference value is larger than the target value x ^* , the immersion depth of the aeration rotor 2 is reduced, and the aerobic region is shortened. That is, Ditch 1
Since the immersion depth of the aeration rotor 2 is automatically adjusted so that the end of the aerobic region will be near the center of the ditch even if the inflow load to the air fluctuates, good processing is possible without measuring or analyzing the nitrogen concentration. It has an effect that the water quality can be maintained stably.

Note that FIG. 31 shows an example in which the target value of the immersion depth, which is the output of the controller 20, is calculated by the calculator 12 as the target value of the height of the overflow 4, but the calculation is adjusted at once. 20 in total
The same effect can be obtained even if the arithmetic unit 12 is omitted.

Example 18. In the seventeenth embodiment, an example in which the point at which the dissolved oxygen concentration reaches the predetermined reference value is estimated from the measured value of the dissolved oxygen concentration and the rotation speed of the aeration rotor 2 is shown. Alternatively, the distribution of the dissolved oxygen concentration may be directly obtained using the dissolved oxygen concentration meter, and the point where the dissolved oxygen concentration becomes a predetermined reference value may be calculated. The device configuration of the embodiment in this case is almost the same as that of FIG. 30, but instead of the controller 16 and the drive device 3, the immersion depth of the aeration rotor 2 is adjusted by the controller 20, the calculator 12 and the drive device 13. . As a result, in addition to the effects of the seventeenth embodiment, there is an effect that the immersion depth of the aeration rotor 2 can be adjusted more precisely.

Example 19 An embodiment according to claim 11 of the present invention will be described with reference to the drawings. 32: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 19. FIG. In FIG. 32, reference numeral 21 denotes a microorganism concentration meter for measuring the concentration of activated sludge microorganisms in the ditch 1, which is installed at an arbitrary point in the ditch 1. 22 is 1/4 of the ditch length in the downflow direction from the installation point of the aeration rotor 2
It is a calculator for calculating the target value of the dissolved oxygen concentration at a point separated by ½ times, and the microorganism concentration meter 21 and the signal line 21a.
Thus, the controller 9 is connected to the signal line 22a. Reference numeral 23 is a setting device for setting a reference value of the dissolved oxygen concentration, which is connected to the calculator 22 by a signal line 23a. Others are Fig. 27
Is the same as

Next, the operation will be described. As described in the fourth law, the higher the MLSS concentration (concentration of activated sludge microorganisms), the steeper the dissolved oxygen concentration distribution in the ditch. That is, the dissolved oxygen concentration slightly ahead of the end of the aerobic region becomes slightly large when the activated sludge microorganism concentration is high, and slightly small when the activated sludge microorganism concentration is low. Therefore, the calculator 22 corrects the target value of the dissolved oxygen concentration by, for example, the formula 21. _{^{DO * H = DO * + K}} SS (MLSS-MLSS 0) ··· (21) here, DO ^* _H: corrected dissolved oxygen concentration target value (correction value in consideration of the activated sludge concentration of microorganisms) DO ^* : Target value of dissolved oxygen concentration K _SS : Constant MLSS: Measured value of activated sludge microorganism concentration MLSS ₀ : Reference value of activated sludge microorganism concentration. The measured value MLSS of the microorganism concentration of activated sludge necessary for this calculation is the signal line 21a as the output of the microorganism concentration meter 21.
And the target value of dissolved oxygen concentration DO ^* Is the setting device 2
3 is output via the signal line 23a. The calculation result DO ^* _H is transmitted to the controller 9 which outputs the target value of the rotation speed of the aeration rotor 2 through the signal line 22a, and will be described below with reference to FIG.
It operates similarly to the thirteenth embodiment shown in FIG.

By this, the measured value of the activated sludge microbial concentration
MLSS is the reference value MLSS₀ A greater than
1/4 to 1/2 times the ditch length from the data 2 in the downflow direction
Target value DO of dissolved oxygen concentration at a distance^* Is larger
Will be corrected. Therefore, the dissolved oxygen concentration distribution becomes steep
Can deal with that. Conversely, the measured value of the activated sludge microbial concentration
MLSS is the reference value MLSS₀ Dissolved acid when smaller than
Target value of elementary concentration DO^* Is corrected to be smaller. Therefore,
It is possible to cope with a gentle gradient of the dissolved oxygen concentration distribution. You
That is, in addition to the effect of Example 13, "MLSS concentration is
The higher the distribution, the steeper the dissolved oxygen concentration distribution in the ditch.
More accurate aerobic region that takes into account the fourth law
There is an effect that the adjustment of can be performed.

Example 20. In Example 19, the aeration rotor 2
Although the example of adjusting the number of rotations is shown, the immersion depth of the aeration rotor 2 may be adjusted. The device configuration of the embodiment in this case is almost the same as that of FIG. 32, but the controller 9 and the drive device 3 are used.
Instead of controller 11, calculator 12 and drive unit 13
The immersion depth of the aeration rotor 2 is adjusted by. The arithmetic unit 12 can be omitted. Thereby, in addition to the effect of Example 14, more accurate adjustment of the aerobic region is performed in consideration of the fourth law that "the higher the MLSS concentration, the steeper the dissolved oxygen concentration distribution in the ditch". There is an effect that can be.

Example 21. An embodiment according to claim 12 of the present invention will be described with reference to the drawings. 33: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 21. As shown in FIG. In FIG. 33, 24 indicates that the dissolved oxygen concentration in the ditch 1 is 0 from the measured value of the dissolved oxygen concentration, the rotation speed of the aeration rotor 2 and the measured value of the activated sludge microbial concentration.
The signal line 8 is a calculator for calculating the point where the reference value of the dissolved oxygen concentration set in advance to a value near [mg / L] is reached.
It is connected to the dissolved oxygen concentration meter 8 at a. The dissolved oxygen concentration meter 8 is installed in a range from the installation position of the aeration rotor 2 to a position separated by 0 to 1/2 times the ditch length in the downflow direction. The calculator 24 is also connected to the aeration rotor 2 via the signal line 2a and the setter 15 for setting the reference value of the dissolved oxygen concentration via the signal line 15a. The signal line 21a is also connected to the microorganism concentration meter 21, and the signal line 24a is also connected to the controller 16 that outputs the target value of the rotation speed of the aeration rotor 2. Others are the same as in FIG.

Next, the operation will be described. Calculator 24
Then, for example, the point at which the dissolved oxygen concentration in the ditch 1 reaches a predetermined reference value of the dissolved oxygen concentration is calculated by using Equations 17 and 22. the _{x H = x × Rr 0 /} Rr (MLSS) Rr (MLSS) = Rr 0 + K MLSS (MLSS-MLSS 0) ··· (22) wherein, x _H: ditch 1 inside the dissolved oxygen concentration is predetermined Distance from the point where the dissolved oxygen concentration meter reaches the reference value of the dissolved oxygen concentration 8 in the downflow direction (correction value of x considering the activated sludge microbial concentration) Rr ₀ : Reference value of dissolved oxygen consumption rate Rr (MLSS) : Dissolved oxygen consumption rate obtained from activated sludge microorganism concentration K _MLSS : Constant. The measured value MLSS of the activated sludge microbial concentration required for the calculation of the equation 22 is the signal line 2 as the output of the microbial concentration meter 21.
Obtained via 1a. The calculation result x _H is transmitted to the controller 16 that outputs the target value of the rotation speed of the aeration rotor 2 via the signal line 24a, and thereafter, the same operation as that of the fifteenth embodiment shown in FIG. 29 is performed.

Thus, when the measured value MLSS of the activated sludge microorganism concentration is large, the term Rr (ML
Since SS) becomes large, the distance x _H of the reference value reaching point is corrected to be shorter than the distance x. Therefore, it is possible to deal with the steep gradient of the dissolved oxygen concentration distribution. On the contrary, when the measured value MLSS of the activated sludge microorganism concentration is small, the dissolved oxygen consumption rate term Rr (MLSS) becomes small, so the distance x _H at the reference value reaching point is corrected to be longer than the distance x.
Therefore, it can be dealt with that the dissolved oxygen concentration distribution has a gentle gradient. That is, in addition to the effects of Example 15, “MLS
The dissolved oxygen concentration distribution in the ditch becomes steeper as the S concentration increases, which brings about the effect of enabling more accurate adjustment of the aerobic region in consideration of the fourth law.

Example 22. In the twenty-first embodiment, the example in which the rotation speed of the aeration rotor 2 is adjusted has been shown, but the immersion depth of the aeration rotor 2 may be adjusted. The device configuration of the embodiment in this case is almost the same as that of FIG. 33, but instead of the controller 16 and the driving device 3, the immersion depth of the aeration rotor 2 is adjusted by the controller 20, the calculator 12 and the driving device 13. . Calculator 1
2 can be omitted. Thus, in addition to the effect of Example 17, more accurate adjustment of the aerobic region is performed in consideration of the fourth law that "the higher the MLSS concentration, the steeper the dissolved oxygen concentration distribution in the ditch". There is an effect that can be.

Example 23. An embodiment according to claim 10 of the present invention will be described with reference to the drawings. 34: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 23. As shown in FIG. In FIG. 34, reference numeral 25 is a total nitrogen concentration meter attached to a pipe c for discharging the precipitation treated water. Reference numeral 26 is a memory circuit for storing the relationship between the MLSS concentration in the ditch 1 and the total nitrogen concentration in the treated water,
The signal line 25a is connected to the total nitrogen concentration meter 25. The calculator 22 calculates the target value of the dissolved oxygen concentration at a point distant from the installation point of the aeration rotor 2 by 1/4 to 1/2 times the ditch length in the downflow direction. Reference numeral 27 is a setting device for setting a target value of the total nitrogen concentration in the treated water, and a signal line 27a
And is connected to the storage circuit 26. 28 is a memory circuit 26
It is a controller that outputs the excess sludge removal amount according to the deviation between the target value of the MLLS concentration and the measured value of the MLSS concentration that are output by the memory circuit 26 by the signal line 26a and the microbial concentration (MLSS by the signal line 21b. Concentration) meter 21 and signal line 28a are connected to excess sludge drawing pump 6.
Others are the same as in FIG. 32.

Next, the operation will be described. The total nitrogen concentration in the treated water is the total nitrogen concentration meter 25 attached to the pipe c.
Is measured at. The measured value of the total nitrogen concentration is transmitted to the storage circuit 26 via the signal line 25a. The memory circuit 26 determines the target value of the MLSS concentration in the ditch 1 from the measured value of the total nitrogen concentration in the treated water and the predetermined target value of the total nitrogen concentration. The target value of total nitrogen concentration in the treated water is the setting device 2
It is set by 7. Only one target value may be set, or two upper limit values and lower limit values may be set. Here, the former case will be described for the sake of brevity. The set target value is transmitted to the memory circuit 26 via the signal line 27a.

Now, in the memory circuit 26, the M in the ditch 1
The relationship between the LSS concentration and the total nitrogen concentration in the treated water is stored. That is, in order to highly remove nitrogen, MLS
It has been shown that it is necessary to keep the S concentration high (second law), but FIG. 35 is an example of obtaining the optimum water quality, and the horizontal axis represents the MLSS concentration [mg / L] in the ditch 1 vertically. The axis shows the total nitrogen concentration [mg / L] in the treated water. The curve in the figure shows the relationship between the total nitrogen concentration and the MLSS concentration when the treated water quality was the best, as a result of simulation with changing the rotor condition for a certain inflow load. FIG.
5, an algorithm for determining the target value of the MLSS concentration in the ditch 1 from the measured value of the total nitrogen concentration in the treated water and the predetermined target value will be described.

The flow rate according to the planned value, for example, 1 in FIG.
When sewage of 5 [m ³ / h] flows in, the MLSS concentration is set so that the treated water quality can be obtained according to the target value (point A). If the total nitrogen concentration measured value is worse than the target value, the inflow rate should be increasing. Therefore, the inflow flow rate is estimated from the combination of the measured value of the total nitrogen concentration and the initially set current MLSS concentration (point B). For example, in FIG. 35, it is 20 [m ³ / h]. According to the MLSS concentration-total nitrogen concentration curve using this new inflow flow rate as a parameter, a new MLSS concentration target value for obtaining the target water quality is determined (point C). Even when the measured value of the total nitrogen concentration is better than the target value, a new MLSS concentration target value can be similarly determined. This new MLSS concentration target value is transmitted to the controller 28. The controller 28 outputs the target value of the excess sludge withdrawal amount according to, for example, Equation 23. Q _drw = Q _drw0 + K _SS (MLSS ^* -MLSS) (23) where Q _drw : Target value of excess sludge removal amount Q _drw0 : Constant K _SS : Constant _MLSS ^* : Target of _MLSS concentration in Ditch 1 The value (new MLSS).

As described above, the target value MLSS ^* of the MLSS concentration in the ditch 1 is obtained as the output of the memory circuit 26 via the signal line 26a. Also, MLS in Ditch 1
The measured value MLSS of the S concentration is obtained from the microorganism concentration meter 21 via the signal line 21b. The output of the controller 28 is the signal line 2
The excess sludge is pumped to the excess sludge extraction pump 6 via 8a, and the excess sludge is extracted in a predetermined amount.

As a result, the optimum MLSS concentration for achieving the target water quality is maintained. On the other hand, since the rotation speed of the aeration rotor 2 is adjusted while being corrected by the measurement value of the MLSS concentration meter 21, in addition to the effect of the nineteenth embodiment, more stable and good treated water quality can be obtained, and at the same time, in the system. The effect of not causing excess or deficiency in the amount of activated sludge microorganisms is obtained.

Example 24. Another embodiment according to claim 10 of the present invention will be described with reference to the drawings. 36: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 25. As shown in FIG. In FIG. 36, reference numeral 29 is a calculator for calculating the target value of the MLSS concentration in the ditch 1 according to the deviation between the measured value of the total nitrogen concentration meter 25 and a predetermined target value, and is connected to the pipe c by the signal line 25a. It is connected to the attached total nitrogen concentration meter 25, a setter 27 for setting a target value of the total nitrogen concentration via a signal line 27a, and a controller 28 for controlling the excess sludge removal amount via a signal line 29a. Others are Figure 3
The same as 4.

Next, the operation will be described. Calculator 29
Then, for example, the target value of the MLSS concentration in the ditch 1 is output according to the equation 24. ^{_{MLSS * = MLSS 0 + K TN1}} (* TN -TN) ··· (24) here, MLSS _0: constant K _TN1: constant TN ^*: is a measure of the total nitrogen concentration: target value TN of the total nitrogen concentration. Target value TN ^{* of} total nitrogen concentration required for this calculation
Is obtained as the output of the setter 27 via the signal line 27a, and the measured value TN of the total nitrogen concentration is obtained as the output of the total nitrogen concentration meter 25 via the signal line 25a. Calculation result MLSS
^* Is transmitted to the controller 28 via the signal line 29a.

As a result, if the measured value TN of total nitrogen concentration is larger than the target value TN ^{*, the} amount of excess sludge drawn out is reduced and the total amount of sludge retained in the system is increased. Therefore, since the MLSS concentration in the ditch 1 increases, the total nitrogen concentration in the treated water tends to decrease. On the contrary, when the measured value TN of the total nitrogen concentration is smaller than the target value TN ^{*, the} amount of excess sludge drawn out increases and the total amount of sludge retained in the system decreases. On the other hand, the rotation speed of the aeration rotor 2 is the MLSS concentration meter 2
It is adjusted while performing correction based on the measurement value of 1. That is, since the optimum MLSS concentration for achieving the target water quality is maintained and the rotation speed of the aeration rotor 2 is adjusted so that the aerobic region length is optimum for the MLSS concentration, the same as in Example 23. Produce the effect of. In this embodiment, M
Since the target value MLSS ^* of the LSS concentration is calculated, the configuration is simpler than that of the twenty-third embodiment using the memory circuit 26.

Example 25. In the above Examples 23 and 24,
For the example of correcting the control target value of the dissolved oxygen concentration in the specific section in the ditch by using the optimized reference value of MLSS concentration and the measured value of MLSS concentration, the optimum MLSS concentration to achieve the target water quality Was calculated and the amount of sludge drawn out was controlled so as to reach the target value of this MLSS concentration, but no correction may be performed. As a device configuration of the embodiment in this case, a configuration is provided in which the calculator 22 and the setter 23 in FIGS. 34 and 36 are omitted, and the setter 10 is provided, and the dissolved oxygen target value is set by the setter 10. Can be considered. As a result, substantially the same effect can be achieved with a simpler device configuration than the twenty-third and twenty-fourth embodiments. As a device configuration similar to this, a microorganism concentration meter 21, a memory circuit 26, a setting device 27 and a controller 28 are provided in FIGS. 19 to 26, and a total nitrogen concentration meter 25 or a nitrate nitrogen concentration meter 100 and A configuration is conceivable in which the output signal from the ammonia nitrogen concentration meter 101 is used to adjust the amount of excess sludge drawn out. As a result, the optimum MLSS concentration for achieving the target water quality is maintained, and at the same time, the aerobic region length is appropriately controlled. Therefore, in addition to the effects of Examples 1 to 12, it is more stable and favorable. It is possible to obtain various treated water qualities, and at the same time, it is possible to obtain an effect that the amount of activated sludge microorganisms in the system is not excessive or insufficient.

Example 26. Still another embodiment according to claim 10 of the present invention will be described with reference to the drawings. 37: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 26. As shown in FIG. In FIG. 37, the memory circuit 2
6 and the calculator 22 are connected by a signal line 26b. In Example 23, the MLSS optimum for achieving the target water quality is compared with the example in which the measured target MLSS concentration is used to correct the control target value of the dissolved oxygen concentration in the specific section in the ditch.
The concentration was calculated, and the amount of sludge drawn was controlled to reach the target value of this MLSS concentration.
Since the LSS concentration eventually becomes the target value of the MLSS concentration, the ML output from the storage circuit 26 in the twenty-sixth embodiment.
The target value MLSS ^* of the SS concentration was input to the calculator 22 instead of the measured MLSS concentration, and the target value of the dissolved oxygen concentration was corrected. By doing so, it is possible to quickly cope with the excess or deficiency in the amount of microorganisms for water treatment.

Example 27. Similarly to the twenty-sixth embodiment, the twenty-fourth embodiment also inputs the target value MLSS ^* of the MLSS concentration output from the computing unit 29 to the computing unit 22 and is measured when correcting the target value of the dissolved oxygen concentration. It may be used instead of the MLSS concentration.

Example 28. An embodiment according to claim 13 of the present invention will be described with reference to the drawings. 38: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 28. As shown in FIG. In FIG. 38, reference numeral 30 is a controller that outputs a target value of the excess sludge removal amount according to a deviation between the measured value of the total nitrogen concentration meter 25 and a predetermined target value of the total nitrogen concentration, and a pipe for the signal line 25a. It is connected to the total nitrogen concentration meter 25 attached to c and also to the excess sludge drawing pump 6 by a signal line 30a. Reference numeral 27 is a setting device for setting a target value of the total nitrogen concentration, which is connected to the controller 30 via a signal line 27a. Others are the same as in FIG. 32.

Next, the operation will be described. Controller 30
Then, for example, the target value of the excess sludge withdrawal amount is output according to Equation 25. Q _drw = Q _drw0 + K _drw (TN ^* -TN) (25) where K _TN2 is a constant. Target value TN ^{* of} total nitrogen concentration required for this calculation
Is obtained as the output of the setter 27 via the signal line 27a, and the measured value TN of the total nitrogen concentration is obtained as the output of the total nitrogen concentration meter 25 via the signal line 25a. The calculation result Q _drw is transmitted to the excess sludge drawing pump 6 through the signal line 30a.

As a result, if the measured value TN of total nitrogen concentration is larger than the target value TN ^{*, the} amount of excess sludge drawn out is reduced and the total amount of sludge retained in the system is increased. Therefore, since the MLSS concentration in the ditch 1 increases, the total nitrogen concentration in the treated water tends to decrease. On the contrary, when the measured value TN of the total nitrogen concentration is smaller than the target value TN ^{*, the} amount of excess sludge drawn out increases and the total amount of sludge retained in the system decreases. On the other hand, the rotation speed of the aeration rotor 2 is the MLSS concentration meter 2
It is adjusted while performing correction based on the measurement value of 1. That is, the optimum MLSS concentration for achieving the target water quality is maintained, and the rotation speed of the aeration rotor 2 is adjusted so that the aerobic region length is optimum for the MLSS concentration. In addition to this, it is possible to obtain a more stable and favorable treated water quality, and at the same time, it is possible to obtain an effect that the amount of activated sludge microorganisms in the system does not become excessive or insufficient.

Example 29. In the above Example 28, the amount of sludge drawn out so as to achieve the target water quality, in contrast to the example in which the control target value of the dissolved oxygen concentration in the specific section in the ditch is corrected using the optimized reference value of the MLSS concentration. Although it has been controlled, it may not be corrected. As the apparatus configuration of the embodiment in this case, the microorganism concentration meter 21, the calculator 22, and the setting device 23 in FIG. 38 are omitted, but a setting device 10 is provided, and the setting of the dissolved oxygen concentration target value is performed by the setting device 10. It is conceivable to perform the configuration. As a result, substantially the same effect can be obtained with a simpler device configuration than the twenty-eighth embodiment. In addition, as a device configuration similar to this, a setting device 27 and a controller 30 are provided in FIGS. 19 to 26, and outputs from the total nitrogen concentration meter 25, or the nitrate nitrogen concentration meter 100 and the ammonia nitrogen concentration meter 101. It is possible to use a signal to adjust the amount of excess sludge drawn out.
As a result, the optimum MLSS to achieve the target water quality
At the same time that the concentration is maintained, the aerobic region length is also appropriately controlled. Therefore, in addition to the effects of Examples 1 to 12, more stable and favorable treated water quality can be obtained, and at the same time, activated sludge in the system can be obtained. The effect that neither excess nor deficiency occurs in the amount of microorganisms is exhibited.

Example 30. In the above Examples 23 to 29,
Although the example in which the rotation speed of the aeration rotor 2 is adjusted has been described, the immersion depth of the aeration rotor 2 may be adjusted. The device configuration of the embodiment in this case is almost the same as that of FIGS. 34, 36, 37 and 38, but instead of the controller 9 and the drive device 3, the controller 1 is used.
1. The immersion depth of the aeration rotor 2 is adjusted by the arithmetic unit 12 and the drive device 13. The arithmetic unit 12 can be omitted. As a result, in addition to the effects of Example 14 or Example 20, more stable and favorable treated water quality is obtained, and at the same time, there is no excess or deficiency in the amount of activated sludge microorganisms in the system.

Example 31. Examples 23 to 30 show examples in which the rotational speed or the immersion depth of the aeration rotor 2 is adjusted by using the measured value of the dissolved oxygen concentration in the specific section in the ditch 1, but Examples 15 to 18, 21, It is also possible to estimate a point where the dissolved oxygen concentration reaches a predetermined reference value as in 22 and adjust the rotation speed or the immersion depth of the aeration rotor 2 so that this point is always at a predetermined point. The apparatus configuration of the embodiment in this case is almost the same as that of FIGS. 34, 36, 37 and 38, but when the number of revolutions is adjusted, the configuration of that part is as shown in FIG. When adjusting the immersion depth, instead of the controller 16 and the driving device 3, the controller 2 is used.
0, the calculator 12 and the drive unit 13 adjust the immersion depth of the aeration rotor 2. The arithmetic unit 12 can be omitted. As a result, in addition to the effects of Examples 15 to 18, 21, and 22, more stable and favorable treated water quality can be obtained, and at the same time, there is no excess or deficiency in the amount of activated sludge microorganisms in the system.

Example 32. In Examples 23 to 31, an example of measuring the total nitrogen concentration in the treated water was shown, but the present invention is not limited to this as long as it is an index showing the water quality of the treated water, and the organic matter concentration, the total phosphorus concentration, etc. may be measured. .

Example 33. Examples 1-12, 23-32
In the above, an example is shown in which a means for measuring the quality of treated water, such as a nitrate nitrogen concentration meter 100 and an ammonia nitrogen concentration meter 101, is installed in the pipe c for discharging the precipitated treated water. Whichever comes first. In addition, the means for measuring the treated water quality is such that the effluent water from the ditch 1
It may be installed in the pipe b for introducing into the tank or in the vicinity of the treated water outflow point in the ditch 1.

Example 34. An embodiment according to claim 14 of the present invention will be described with reference to the drawings. 39: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 34. As shown in FIG. In FIG. 39, reference numeral 31 is a thermometer for measuring the water temperature in the ditch 1, which is installed at an arbitrary point in the ditch. Reference numeral 32 is a calculator for calculating a target value of the dissolved oxygen concentration at a point separated by 1/4 to 1/2 times the Ditch length from the installation point of the aeration rotor 2 in the downflow direction, and is a thermometer 31 and a signal line 31a. It is connected to the controller 9 by a signal line 32a. Reference numeral 33 is a setter for setting parameters for calculating the target value of the dissolved oxygen concentration, and the signal line 33a
Is connected to the computing unit 32. Others are the same as in FIG. 27.

Next, the operation will be described. As described in the third law, the optimum end position of the aerobic region for the quality of treated water is affected by fluctuations of factors that affect microbial activity such as water temperature, pH, and redox potential. Specifically, when the nitrification rate is higher than the denitrification rate, it shifts to the front (aeration rotor side), and when the denitrification rate is higher than the nitrification rate, it shifts backward. Therefore, the calculator 32 calculates the target value of the dissolved oxygen concentration according to, for example, Expression 26. _{^{DO H1 * = DO * × K}} D θ D T-20 / K N θ N T-20 ··· (26) here, DO _H1 ^*: dissolved oxygen concentration target value (correction value in consideration of the water temperature) K _D : Denitrification rate at a water temperature of 20 ° C θ _D : Constant K _N : Nitrification rate at a water temperature of 20 ° C θ _N : Constant T: Temperature. The water temperature T in the ditch 1 required for this calculation is output from the thermometer 31 via the signal line 31a, and the parameter for the calculation is output from the setter 33 to the signal line 33a.
It is obtained via a. The calculation result DO _H1 ^* is the signal line 32a
Is transmitted to the controller 9 that outputs the target value of the rotation speed of the aeration rotor 2.

As a result, when the denitrification rate is higher than the nitrification rate, the ditch length is 1 in the downward direction from the aeration rotor 2.
The target value of the dissolved oxygen concentration at a point ½ times away from / 4 is corrected to a large extent. Therefore, it is possible to deal with the case where the optimum end position of the aerobic region for the treated water quality is displaced rearward from the vicinity of the center of the ditch. On the contrary, when the nitrification rate is higher than the denitrification rate, the target value of the dissolved oxygen concentration is corrected to be smaller. Therefore, it is possible to deal with the case where the optimum end position of the aerobic region for the treated water quality is displaced rearward from the vicinity of the center of the ditch. That is, in addition to the effect of the thirteenth embodiment, "the optimum end position of the aerobic region for the treated water quality is the water temperature, p
It is possible to perform more accurate regulation of the aerobic region in consideration of the third law "that is affected by fluctuations in factors that affect microbial activity such as H and redox potential."

Example 35. In Example 34, the aeration rotor 2
Although the example of adjusting the number of rotations is shown, the immersion depth of the aeration rotor 2 may be adjusted. The device configuration of the embodiment in this case is almost the same as that of FIG. 39, but the controller 9 and the drive device 3 are used.
Instead of controller 11, calculator 12 and drive unit 13
The immersion depth of the aeration rotor 2 is adjusted by. The arithmetic unit 12 can be omitted. As a result, in addition to the effect of Example 14, "the optimum end position of the aerobic region with respect to the treated water quality is affected by changes in factors that affect microbial activity such as water temperature, pH, and redox potential". The effect that the aerobic region can be adjusted more accurately in consideration of the third law is obtained.

Example 36. An embodiment according to claim 15 of the present invention will be described with reference to the drawings. 40: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 36. As shown in FIG. In FIG. 40, 34 indicates that the dissolved oxygen concentration in the ditch 1 is 0 [m from the measured value of the dissolved oxygen concentration, the rotation speed of the aeration rotor 2 and the measured value of the water temperature in the ditch 1.
[g / L] is a calculator for calculating the point at which the reference value of the dissolved oxygen concentration reaches a preset value in the vicinity of [g / L], and is connected to the dissolved oxygen concentration meter 8 via a signal line 8a. Dissolved oxygen concentration meter 8
Is a ditch length of 0 from the installation point of the aeration rotor 2 in the downflow direction.
It will be installed in a range up to 1/2 times away. The calculator 34 uses the signal line 2a to connect the aeration rotor 2 and the signal line 15a.
It is also connected to the setting device 15 for setting the reference value of the dissolved oxygen concentration. Moreover, the thermometer 31 is connected to the signal line 31a.
The signal line 34a is also connected to the controller 16 that outputs the target value of the rotation speed of the aeration rotor 2. Others are shown in FIG.
Is the same as

Next, the operation will be described. Calculator 34
Then, the point where the dissolved oxygen concentration in the ditch 1 reaches a predetermined reference value of the dissolved oxygen concentration is calculated by, for example, Equation 17 and Equation 27. X _H2 = X × K _D θ _D ^T-20 / K _N θ _N ^T-20 (27) Here, X _H2 : The dissolved oxygen concentration in the ditch 1 is set to a predetermined reference value of the dissolved oxygen concentration. It is the distance (correction value considering water temperature) from the installation point of the dissolved oxygen concentration meter 8 at the reaching point. The measured value of the activated sludge microbial concentration required for the calculation of Expression 27 is obtained as the output of the microbial densitometer 31 via the signal line 31a. The calculation result X _H2 is transmitted to the controller 16 which outputs the target value of the rotation speed of the aeration rotor 2 via the signal line 34a.

As a result, when the denitrification rate is higher than the nitrification rate, the distance X _H2 of the point where the reference value of the dissolved oxygen concentration reaches is corrected to be longer than the distance X. Therefore, it is possible to deal with the case where the optimum end position of the aerobic region for the treated water quality is displaced rearward from the vicinity of the center of the ditch. On the contrary, when the nitrification rate is higher than the denitrification rate, the distance X _H2 at the point where the reference value of the dissolved oxygen concentration reaches is corrected to be shorter than the distance X. Therefore, it is possible to deal with the case where the optimum end position of the aerobic region for the treated water quality is displaced rearward from the vicinity of the center of the ditch. That is, in addition to the effects of Example 15, the "the optimum end position of the aerobic region for the treated water quality is affected by fluctuations in factors that affect microbial activity such as water temperature, pH, and redox potential". This brings about the effect that the aerobic region can be adjusted more accurately in consideration of the law of 3.

Example 37. In Example 36, the aeration rotor 2
Although the example of adjusting the number of rotations is shown, the immersion depth of the aeration rotor 2 may be adjusted. The device configuration of the embodiment in this case is almost the same as that of FIG. 40, but instead of the controller 16 and the driving device 3, the controller 20, the calculator 12, and the driving device 1
At 3, the immersion depth of the aeration rotor 2 is adjusted. The arithmetic unit 12 can be omitted. As a result, in addition to the effect of Example 17, "the optimum end position of the aerobic region for the treated water quality is affected by fluctuations of factors affecting microbial activity such as water temperature, pH, and redox potential". The effect that the aerobic region can be adjusted more accurately in consideration of the third law is obtained.

Example 38. In Examples 34 to 37, an example was shown in which the target value of the dissolved oxygen concentration in the specific section in the ditch 1 was corrected by considering only the water temperature, but the correction considering the MLSS concentration as in Examples 19 to 33 was also performed. You can do it. The device configuration of the embodiment in this case is almost the same as that of FIGS. 32 and 33 or FIGS. 34 and 36, but a signal from the water temperature gauge 31 is input to the calculator 22 through the signal line 31a,
For example, the target value of the dissolved oxygen concentration at a point separated by ¼ to ½ times the Ditch length from the point where the aeration rotor 2 is installed in the downflow direction is calculated by Equation 28. DO _H2 ^* = DO _H ^* × K _D θ _D ^T-20 / K _N θ _N ^T-20・ ・ ・ (28)

Alternatively, the signal from the water temperature gauge 31 is sent to the signal line 3
It is input to the calculator 24 via 1a, and the point where the dissolved oxygen concentration in the ditch 1 reaches a predetermined reference value of the dissolved oxygen concentration is calculated by, for example, formula 29. X _H2 = X _H × K _D θ _D ^T-20 / K _N θ _N ^T-20 (29)

When adjusting the immersion depth of the aeration rotor 2, instead of the controller 9 or 16, and the drive unit 3, the controller 11 or 20, the calculator 12, and the drive unit 13 are used. The arithmetic unit 12 can be omitted.

Thus, in addition to the effects of Examples 19 to 33, "the optimum end position of the aerobic region for the treated water quality is the fluctuation of factors such as water temperature, pH, and redox potential that affect microbial activity. This brings about an effect that more accurate adjustment of the aerobic region can be performed in consideration of the third law of "being affected."

Example 39. Although the examples using the thermometer are shown in Examples 34 to 38, the same effect can be obtained by using the pH meter or the oxidation-reduction potentiometer. In this case, equations 26 to 29
Instead of the calculation shown in, the calculation is performed in consideration of the influence of the pH or the redox potential on the nitrification rate and the denitrification rate.

Example 40. An embodiment according to claim 16 of the present invention will be described with reference to the drawings. 41: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 40. As shown in FIG. In FIG. 41, reference numeral 35 is a flow meter attached to a pipe a for introducing sewage into the ditch 1. Reference numeral 36 is a calculator for calculating the reference value of the number of revolutions of the aeration rotor 2.
It is connected to a controller 9 that calculates a target value of the rotation speed of the aeration rotor 2 at 5a. Others are the same as in FIG. 27.

Next, the operation will be described. Example 13
As shown in, the dissolved oxygen concentration in a specific section in the ditch 1 is measured, and the measured value is used to adjust the rotation speed of the aeration rotor 2 to keep the dissolved oxygen concentration at the measurement point constant. By doing so, an aerobic region and an anaerobic region can be appropriately formed in the ditch 1 and good treated water quality can be obtained. However, in this method, the aeration rotor is adjusted only after the biochemical reaction in the tank progresses and the dissolved oxygen concentration changes, so there is a possibility that the response will be delayed if there is a sudden inflow load change. There is. Therefore, the flow rate of the sewage flowing into the ditch 1 is measured, the reference value of the rotation speed of the aeration rotor 2 is adjusted in advance using this measurement value, and then the balance between the aerobic region and the anaerobic region is adjusted. By doing so, it is possible to stably maintain good treated water quality even with a sudden change in the inflow rate.

The flow rate of the sewage flowing into the ditch 1 is equal to that of the pipe a.
It is measured by the flow meter 35 attached to and is transmitted to the computing unit 36 via the signal line 35a. In the computing unit 36, for example, the reference value R _rot0 of the rotation speed of the aeration rotor 2 is calculated by the formula 30.
Is calculated. R _rot0 = K _Qin Q _in (30) where K _{Qin is a} constant Q _in is the flow rate of sewage flowing into the ditch 1. This calculation result is transmitted to the controller 9 for calculating the target value of the rotation speed of the aeration rotor 2 via the signal line 35a.

As a result, the reference value of the rotation speed of the aeration rotor 2 is set to a large value in advance when the inflow rate is large. On the contrary, when the inflow rate is small, the reference value of the rotation speed of the aeration rotor 2 is set to a small value in advance. This gives Example 13
In addition to the above effect, there is an effect that it is possible to stably maintain good treated water quality even with a sudden change in inflow rate.

Example 41. In Example 40, the aeration rotor 2
Although the example of adjusting the number of rotations is shown, the immersion depth of the aeration rotor 2 may be adjusted. The device configuration of the embodiment in this case is almost the same as that of FIG. 41, but the controller 9 and the drive device 3 are used.
Instead of controller 11, calculator 12 and drive unit 13
The calculation result of the calculator 34 (reference value of the immersion depth of the aeration rotor 2) is input to the controller 11. The arithmetic unit 12 can be omitted. As a result, in addition to the effects of the fourteenth embodiment, there is an effect that it is possible to stably maintain good treated water quality even with a sudden change in the inflow rate.

Example 42. In Examples 40 and 41, the example in which the rotational speed or the immersion depth of the aeration rotor 2 is adjusted by using the measured value of the dissolved oxygen concentration in the specific section in the ditch 1 was shown, but the dissolved oxygen concentration is a predetermined reference value. Is estimated, and the aeration rotor 2 is set so that this is always at a predetermined point.
The method of adjusting the number of rotations or the immersion depth, and the method of correcting the dissolved oxygen concentration or the reference value reaching point in consideration of microbial activity such as microbial concentration, temperature, pH, redox potential, of course, nitrate nitrogen concentration, The same effect can be obtained by adjusting the rotation speed or the immersion depth of the aeration rotor 2 using the concentration difference or concentration ratio between the ammonia nitrogen concentration and the total nitrogen concentration. As in the case of FIG. 41, the device configuration of the embodiment in these cases may include the flowmeter 35 and the calculator 36, and the calculation result of the calculator 36 can be used as the rotation speed controller of the aeration rotor 2 or the immersion depth controller. input.

Example 43. In Examples 40 to 42, the example in which the measured value of the inflow flow rate of the sewage into the ditch 1 is used is shown.

Example 44. In Examples 40 to 42, the example in which the measured value of the inflow flow rate of the sewage into the ditch 1 is used is shown, but the same effect can be obtained even if the measured value of the concentration of the inflowing contaminant, for example, total nitrogen is used.

Example 45. In Examples 40 to 42, the example in which the measured value of the inflow flow rate of the sewage into the ditch 1 is used is shown, but the same effect can be obtained by using the inflow pollutant, for example, the inflow total nitrogen amount obtained by multiplying the concentration of total nitrogen. Play.

Example 46. An embodiment according to claim 17 of the present invention will be described with reference to the drawings. 42: is a block diagram which shows the control apparatus of the oxidation ditch water treatment apparatus which concerns on Example 46. As shown in FIG. In FIG. 42, reference numeral 37 is a flow meter attached to a pipe b for introducing the outflow water from the ditch 1 into the settling basin 5. Reference numeral 38 is a controller that outputs a target value of the height of the overflow 4, and the flowmeter 37 is connected by a signal line 37a.
And the signal line 38a is connected to the drive device 13 of the overflow weir 4. Others are the same as in FIG.

Next, the operation will be described. Ditch 1
The flow rate flowing out from is measured by the flow meter 37 attached to the pipe b and is transmitted to the controller 38 via the signal line 37a. In the controller 38, the overflow 4
A target value for the height of is calculated. _{H = H 0 + K Qout (} Q out -Q out0) ··· (31) Here, K _Qout: Factor Q _out: flow rate flowing out from the ditch 1 Q _out0: the reference value of the flow rate flowing out of the ditch 1. This calculation result H is transmitted to the drive device 13 via the signal line 38a, and the height of the overflow weir 4 is adjusted.

As a result, if the flow rate Q _out flowing out of the ditch 1 is larger than the reference value Q _out0 , the height H of the overflow _weir 4 is increased, and the outflow amount, that is, the inflow amount into the sedimentation basin 5 is reduced. At the same time, the immersion depth of the aeration rotor 2 increases and the amount of aeration increases. On the contrary, if the flow rate Q _out flowing out of the ditch 1 is smaller than the reference value Q _out0 , the height H of the overflow _weir 4 becomes low, and the outflow amount, that is, the inflow amount into the settling tank 5 increases, and at the same time, the aeration rotor. The dipping depth of 2 decreases and the aeration amount decreases. That is, even if the flow rate of the sewage flowing into the ditch 1 changes, the flow rate flowing out to the settling basin 5 is always kept constant, and the solid-liquid separation treatment is satisfactorily performed in the settling basin 5. Further, the immersion depth of the aeration rotor 2 can be adjusted at the same time.

Example 47. In the example of adjusting the immersion depth of the aeration rotor among the above-mentioned embodiments, the case where the height of the overflow is changed has been described, but even if the installation position of the aeration rotor itself is changed, it is the same as the above-mentioned embodiment. Produce the effect of.

In each of the embodiments described above, the case where the aeration rotor is used is shown, but other aeration devices,
For example, it can be applied to the case where an axial flow pump type aerator, a screw type aerator or the like is used.

Further, in each of the above-mentioned embodiments, the case of removing nitrogen has been shown, but it is also applicable to the case of removing other contaminants such as organic matter or phosphorus.

Furthermore, in each of the above-mentioned embodiments, the time continuous analog type is used. However, even if the time discontinuous analog type (sample value type) or digital type is used, the same effect as that of the above-described embodiments can be obtained. .

Further, although the control circuit configuration is shown in the above embodiment, the same effect as that of the above embodiment can be obtained even if the control circuit configuration is programmed and mounted in a computer.

Further, in the above-mentioned embodiment, the control circuit is constructed as a closed loop, but it may be constructed as a driving support system for presenting the control target value to the operator.

[0177]

As described above, according to the invention of claim 1, the control device of the oxidation ditch water treatment device comprises means for measuring the nitrate nitrogen concentration in the treated water, and ammonia nitrogen concentration in the treated water. A controller for outputting a target value of the number of revolutions of the aeration rotor or the immersion depth according to a deviation between the difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration and the target value of the predetermined concentration difference. And the means for adjusting the number of rotations or the immersion depth of the aeration rotor according to the target value of the number of rotations or the immersion depth, the end of the aerobic region can be controlled and good treated water quality can be stabilized. The effect is that it can be maintained.

According to the second aspect of the present invention, the target value of the concentration difference is set in the range of -10 to 10 [mg / liter], so that the end of the aerobic region is near the center of the ditch. There is an effect that it can be automatically adjusted so that the quality of the treated water can be kept stable.

According to the third aspect of the present invention, the control device of the oxidation ditch water treatment device comprises a means for measuring the concentration of nitrate nitrogen in the treated water, and a means for measuring the concentration of ammonia nitrogen in the treated water. A controller that outputs the rotation speed of the aeration rotor or the target value of the immersion depth according to the deviation between the concentration ratio between the nitrate nitrogen concentration and the ammonia nitrogen concentration and the target value of the predetermined concentration ratio, and the rotation speed. Alternatively, it is configured with means for adjusting the rotation speed of the aeration rotor or the immersion depth according to the target value of the immersion depth, so the end of the aerobic region can be controlled and good treated water quality can be maintained stably. The effect is that you can do it.

Further, according to the invention of claim 4, since the target value of the concentration ratio is set in the range of 0.1 to 10, the aerobic region is automatically set so that the end thereof is near the center of the ditch. There is an effect that the quality of the treated water can be stably maintained and good treated water quality can be stably maintained.

Further, according to the invention of claim 5, the control device of the oxidation ditch water treatment device comprises: a means for measuring the total nitrogen concentration in the treated water; a means for measuring the nitrate nitrogen concentration in the treated water; A controller that outputs the target value of the number of revolutions of the aeration rotor or the immersion depth according to the deviation of the concentration ratio between the nitrogen concentration and the nitrate nitrogen concentration and the target value of the predetermined concentration ratio, and the number of revolutions or immersion Since it is configured with means for adjusting the rotation speed of the aeration rotor or the immersion depth according to the target depth value, the end of the aerobic region can be controlled and good treated water quality can be stably maintained. effective.

Further, according to the invention of claim 6, the control device of the oxidation ditch water treatment device comprises: a means for measuring the total nitrogen concentration in the treated water; a means for measuring the ammonia nitrogen concentration in the treated water; A controller that outputs the target value of the rotation speed or the immersion depth of the aeration rotor according to the deviation between the concentration ratio of the nitrogen concentration and the ammonia nitrogen concentration and the target value of the predetermined concentration ratio, and the rotation speed or the immersion Since it is configured with means for adjusting the rotation speed of the aeration rotor or the immersion depth according to the target depth value, the end of the aerobic region can be controlled and good treated water quality can be stably maintained. effective.

Further, according to the invention of claim 7, the target value of the ratio of the nitrate nitrogen concentration or the ammonia nitrogen concentration and the total nitrogen concentration is set within the range of 1:10 to 9:10. Therefore, there is an effect that the end of the aerobic region can be automatically adjusted so as to come close to the center of the ditch, and good treated water quality can be stably maintained.

Further, according to the invention of claim 8, the control device of the oxidation ditch water treatment device can be installed in any region in a region away from the aeration rotor installation point in the downflow direction by 1/4 to 1/2 times the ditch length. The means for measuring the dissolved oxygen concentration at the point, and the rotation speed of the aeration rotor or the rotation speed of the aeration rotor according to the deviation between the measured value of the dissolved oxygen concentration and the target value of the dissolved oxygen concentration preset to a value near 0 [mg / liter] Since it is composed of a controller that outputs the target value of the immersion depth and a means for adjusting the rotation speed or the immersion depth of the aeration rotor according to the target value of the rotation speed or the immersion depth, it is possible to measure the nitrogen concentration or Even if the analysis is not performed, the end of the aerobic region can be automatically adjusted so as to be near the center of the ditch, and there is an effect that good treated water quality can be stably maintained.

Further, according to the invention of claim 9, the control device of the oxidation ditch water treatment device is installed at least in a range apart from the aeration rotor installation point in the downflow direction by 0 to 1/2 times the ditch length. Using one or more dissolved oxygen concentration measuring means and the measured value of the dissolved oxygen concentration, the point where the dissolved oxygen concentration in the ditch reaches the reference value of the dissolved oxygen concentration preset to a value near 0 [mg / liter] Aeration is performed according to the calculation means for calculating and the deviation between the calculated value and the target value set in advance in the range apart from the aeration rotor installation point by 1/4 to 3/4 times the ditch length in the downflow direction. Since it consists of a controller that outputs the target value of the rotation speed or immersion depth of the rotor and means for adjusting the rotation speed or immersion depth of the aeration rotor according to the target value of the rotation speed or immersion depth. The rotational speed of the aeration rotor can be automatically adjusted so that the end of the aerobic region is near the center of the ditch without measuring or analyzing the nitrogen concentration, and good treated water quality can be maintained stably. The effect is that you can do it.

According to the invention of claim 10, the control device of the oxidation ditch water treatment device is provided with a means for measuring the concentration of activated sludge microorganisms installed at an arbitrary point in the ditch, and a water quality of the treated water. Means to measure, a calculator that calculates the target value of the activated sludge microbial concentration according to the deviation between the measured value of water quality and the predetermined target value, and the deviation between the target value and the measured value of the activated sludge microbial concentration In accordance with the controller for outputting the target value of the sludge removal amount according to the above, and the means for adjusting the sludge removal amount according to the target value of the sludge removal amount, the aerobic region and the anaerobic region are appropriately set in the ditch. At the same time as the above-mentioned formation, there is an effect that there is no excess or deficiency in the amount of microorganisms for water treatment.

According to the eleventh aspect of the invention, the target value of the dissolved oxygen concentration is corrected from the measured value of the activated sludge microbial concentration at any point in the ditch or the target value of the activated sludge microbial concentration. Therefore, there is an effect that the aerobic region can be adjusted more accurately, and good treated water quality can be stably maintained.

According to the twelfth aspect of the present invention, the point at which the dissolved oxygen concentration reaches the reference value is corrected from the measured value of the activated sludge microbial concentration at any point in the ditch or the target value of the activated sludge microbial concentration. As a result, there is an effect that the aerobic region can be adjusted more accurately, and good treated water quality can be stably maintained.

According to the thirteenth aspect of the present invention, the control device of the oxidation ditch water treatment device is provided with a means for measuring the water quality of the treated water and a deviation between the measured value of the water quality and a predetermined target value. Since it is equipped with a controller that calculates a target value for the amount of sludge withdrawal and a means for adjusting the amount of sludge withdrawal according to the target value for the amount of sludge withdrawal, the aerobic region and the anaerobic region are appropriately set in the ditch. At the same time as the formation, there is an effect that there is no excess or deficiency in the amount of microorganisms for water treatment.

According to the fourteenth aspect of the present invention, means for measuring at least one of water temperature, pH and redox potential is provided at any point in the ditch, and the target value of the dissolved oxygen concentration is determined from these measured values. As a result, the aerobic region can be adjusted more accurately, and good treated water quality can be stably maintained.

According to the fifteenth aspect of the present invention, means for measuring at least one of water temperature, pH and redox potential is provided at an arbitrary point in the ditch, and the reference value of the dissolved oxygen concentration is determined from these measured values. Since the target value at the point reaching to is corrected, the aerobic region can be adjusted more accurately, and good treated water quality can be stably maintained.

According to the sixteenth aspect of the present invention, the control device of the oxidation ditch water treatment device is provided with means for measuring the inflow load to the ditch, and the number of revolutions of the aeration rotor or the immersion depth from the measured value of the inflow load. Since it is provided with a means for calculating the feedforward amount of the reference value of, there is an effect that good treated water quality can be maintained more stably.

According to the seventeenth aspect of the present invention, the control device of the oxidation ditch water treatment device is provided with a means for measuring the outflow rate from the ditch, a measured value of the outflow rate and a predetermined target value of the outflow rate. Since it consists of a controller that outputs the target value of the water level of the ditch according to the deviation of and the means that adjusts the outflow rate according to the target value of the water level, the outflow rate to the sedimentation basin is kept constant, There is an effect that the solid-liquid separation treatment is favorably performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a tank row model used in a computer simulation that has led to the discovery of the first to fourth laws of the present invention.

FIG. 2 is a graph showing the results of computer simulations with the MLSS concentration set to 3000 [mg / L] and the aeration rotor immersion depth set to 15 [cm].

FIG. 3 is a graph showing the results of a computer simulation performed with the MLSS concentration set to 3000 [mg / L] and the aeration rotor immersion depth set to 20 [cm].

FIG. 4 is a graph showing the results of computer simulations with the MLSS concentration set to 3000 [mg / L] and the aeration rotor immersion depth set to 24 [cm].

FIG. 5 is a graph showing the results of computer simulations with the MLSS concentration set to 4000 [mg / L] and the aeration rotor immersion depth set to 15 [cm].

FIG. 6 is a graph showing the results of computer simulation performed with the MLSS concentration set to 4000 [mg / L] and the aeration rotor immersion depth set to 20 [cm].

FIG. 7 is a graph showing the results of a computer simulation in which the MLSS concentration is set to 4000 [mg / L] and the aeration rotor immersion depth is set to 24 [cm].

FIG. 8 is a graph showing the results of computer simulations with the MLSS concentration set to 5000 [mg / L] and the aeration rotor immersion depth set to 15 [cm].

FIG. 9 is a graph showing the results of computer simulation performed with the MLSS concentration set to 5000 [mg / L] and the aeration rotor immersion depth set to 20 [cm].

FIG. 10 is a graph showing the results of computer simulations with the MLSS concentration set to 5000 [mg / L] and the aeration rotor immersion depth set to 24 [cm].

FIG. 11 is a graph showing the relationship between the difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration at point F and the total nitrogen concentration.

FIG. 12 is a graph showing the results of computer simulation with the nitrification rate set to 10 times.

FIG. 13 is a graph showing the result of computer simulation with the nitrification rate set to 10 times.

FIG. 14 is a graph showing the result of computer simulation with the nitrification rate set to 10 times.

FIG. 15 is a graph showing the result of computer simulation performed with the denitrification rate set to 10 times.

FIG. 16 is a graph showing the results of computer simulation with the denitrification rate set to 10 times.

FIG. 17 is a graph showing the results of computer simulation with the denitrification rate set to 10 times.

FIG. 18 is a graph showing the relationship between the dissolved oxygen concentration at point A and the total nitrogen concentration at point F.

FIG. 19 is a configuration diagram showing a control device of the oxidation ditch water treatment device according to the first embodiment of the present invention.

FIG. 20 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a second embodiment of the present invention.

FIG. 21 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a fourth embodiment of the present invention.

FIG. 22 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a fifth embodiment of the present invention.

FIG. 23 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a seventh embodiment of the present invention.

FIG. 24 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to Example 8 of the present invention.

FIG. 25 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a tenth embodiment of the present invention.

FIG. 26 is a configuration diagram showing a controller of an oxidation ditch water treatment device according to Example 11 of the present invention.

FIG. 27 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a thirteenth embodiment of the present invention.

FIG. 28 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a fourteenth embodiment of the present invention.

FIG. 29 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a fifteenth embodiment of the present invention.

FIG. 30 is a configuration diagram showing a controller of an oxidation ditch water treatment device according to Example 16 of the present invention.

FIG. 31 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a seventeenth embodiment of the present invention.

FIG. 32 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a nineteenth embodiment of the present invention.

FIG. 33 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a twenty-first embodiment of the present invention.

FIG. 34 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a twenty-third embodiment of the present invention.

FIG. 35 is a graph showing the relationship between the MLSS concentration and the total nitrogen concentration stored in the memory circuit 26 of the controller of the oxidation ditch water treatment apparatus according to Example 23 of the present invention.

FIG. 36 is a configuration diagram showing a controller of an oxidation ditch water treatment device according to Example 24 of the present invention.

[Fig. 37] Fig. 37 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a twenty-sixth embodiment of the present invention.

FIG. 38 is a configuration diagram showing a control device of the oxidation ditch water treatment apparatus according to Example 28 of the present invention.

FIG. 39 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a thirty-fourth embodiment of the present invention.

FIG. 40 is a configuration diagram showing a control device of an oxidation ditch water treatment device according to a thirty-sixth embodiment of the present invention.

FIG. 41 is a configuration diagram showing a control device for an oxidation ditch water treatment device according to a fortieth embodiment of the present invention.

FIG. 42 is a configuration diagram showing a control device of the oxidation ditch water treatment apparatus according to Example 46 of the present invention.

FIG. 43 is a configuration diagram showing a conventional oxidation ditch water treatment device.

[Explanation of symbols]

1 Ditch 2 Aeration rotor 3 Drive device 4 Overflow weir 5 Sedimentation tank 6 Pump 8, 18 Dissolved oxygen concentration meter 9, 11, 16, 20, 28, 30, 38, 102, 1
04, 107, 108, 110, 111, 113 Controllers 10, 15, 17, 23, 27, 33, 103, 10
6, 109, 112 Setting device 12, 14, 19, 22, 24, 29, 32, 34, 3
6 calculator 13 drive device 21 microorganism concentration meter 25 total nitrogen concentration meter 26 memory circuit 31 thermometer 35, 37 flowmeter 100 nitrate nitrogen concentration meter 101 ammonia nitrogen concentration meter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Shimaoka 1-2-1 Wadazakicho, Hyogo-ku, Kobe Sanryo Electric Co., Ltd.

Claims (17)

[Claims] 1. A control of an oxidation ditch water treatment device for injecting treated water into a ditch, performing activated sludge treatment by a mechanical aeration device provided in the ditch, and removing nitrogen components in the treated water. In the device, means for measuring the nitrate nitrogen concentration in the treated water, means for measuring the ammonia nitrogen concentration in the treated water, the concentration difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration, the predetermined above A controller that outputs the target value of the rotation speed or the immersion depth of the aeration device according to the deviation from the target value of the concentration difference,
And a controller for an oxidation ditch water treatment device, which is provided with adjusting means for adjusting the rotation speed or the immersion depth of the aeration device according to the target value of the rotation speed or the immersion depth. 2. The target value of the concentration difference between the nitrate nitrogen concentration and the ammonia nitrogen concentration in the treated water is -10 to 10 [mg /
[Liters]] is set in the range of [1].
Control device for the described oxidation ditch water treatment device. 3. Control of an oxidation ditch water treatment device for injecting treated water into a ditch, performing activated sludge treatment by a mechanical aeration device provided in the ditch, and removing nitrogen components in the treated water. In the device, means for measuring the nitrate nitrogen concentration in the treated water, means for measuring the ammonia nitrogen concentration in the treated water, the nitrate nitrogen concentration and the ammonia nitrogen concentration and concentration ratio, the predetermined concentration According to the deviation from the target value of the ratio controller for outputting the target value of the rotation speed or immersion depth of the aeration device, and according to the target value of the rotation speed or the immersion depth, the rotation speed of the aeration device or A control device for an oxidation ditch water treatment device, comprising an adjusting means for adjusting the immersion depth. 4. The oxidation ditch according to claim 3, wherein the target value of the concentration ratio value of the nitrate nitrogen concentration and the ammonia nitrogen concentration in the treated water is set in the range of 0.1 to 10. Control device for water treatment equipment. 5. A control of an oxidation ditch water treatment device for injecting treated water into a ditch, performing activated sludge treatment by a mechanical aeration device provided in the ditch, and removing nitrogen components in the treated water. In the device, means for measuring the total nitrogen concentration in the treated water, means for measuring the nitrate nitrogen concentration in the treated water, the concentration ratio between the total nitrogen concentration and the nitrate nitrogen concentration, the predetermined concentration ratio According to the deviation from the target value of the controller for outputting the target value of the rotation speed or the immersion depth of the aeration device, and according to the target value of the rotation speed or the immersion depth, the rotation speed or immersion of the aeration device A control device for an oxidation ditch water treatment device, which is provided with an adjusting means for adjusting the depth. 6. Control of an oxidation ditch water treatment device for injecting treated water into a ditch, performing activated sludge treatment by a mechanical aeration device provided in the ditch, and removing nitrogen components in the treated water. In the device, means for measuring the total nitrogen concentration in the treated water, means for measuring the ammonia nitrogen concentration in the treated water, the concentration ratio between the total nitrogen concentration and the ammonia nitrogen concentration, the predetermined concentration ratio According to the deviation from the target value of the controller for outputting the target value of the rotation speed or the immersion depth of the aeration device, and according to the target value of the rotation speed or the immersion depth, the rotation speed or immersion of the aeration device A control device for an oxidation ditch water treatment device, which is provided with an adjusting means for adjusting the depth. 7. The target value of the ratio of the concentration of nitrate nitrogen or ammonia nitrogen in the treated water to the total nitrogen concentration is 1: 1.
The control device of the oxidation ditch water treatment device according to claim 5 or 6, wherein the control device is set in a range of 0 to 9:10. 8. A control of an oxidation ditch water treatment device for injecting treated water into a ditch, performing activated sludge treatment by a mechanical aeration device provided in the ditch, and removing nitrogen components in the treated water. In the equipment, 1/4 to 1/2 of the ditch length in the downflow direction from the aeration equipment installation point
Means for measuring the dissolved oxygen concentration at an arbitrary point in a doubled region, deviation between the measured value of the dissolved oxygen concentration and the target value of the dissolved oxygen concentration preset to a value near 0 [mg / liter] A controller that outputs a target value of the rotation speed or the immersion depth of the aeration device according to the above, and an adjustment that adjusts the rotation speed or the immersion depth of the aeration device according to the rotation speed or the target value of the immersion depth. A control device for an oxidation ditch water treatment device, which is provided with a means. 9. A control of an oxidation ditch water treatment device for injecting treated water into a ditch, performing activated sludge treatment by a mechanical aeration device provided in the ditch, and removing nitrogen components in the treated water. In the apparatus, at least one or more dissolved oxygen concentration measuring means installed in a range distant from the aeration device installation point in the downflow direction by 0 to 1/2 times the ditch length, and dissolved oxygen measured by the dissolved oxygen concentration measuring means. Calculating means for calculating the point where the dissolved oxygen concentration in the ditch reaches the reference value of the dissolved oxygen concentration preset to a value near 0 [mg / liter], using the measured value of the concentration;
The calculated value calculated by this calculating means and the target value of the point that reaches the above-mentioned reference value, which is set in advance in a range separated by 1/4 to 3/4 times the Ditch length from the aeration device installation point in the downflow direction. According to the deviation from the controller to output the target value of the rotation speed or immersion depth of the aeration device, and according to the target value of the rotation speed or the immersion depth, the rotation speed or immersion depth of the aeration device A control device for an oxidation ditch water treatment device, comprising an adjusting means for adjusting. 10. A means for measuring the concentration of activated sludge microorganisms installed at an arbitrary point in a ditch, a means for measuring the quality of treated water, and a deviation between the measured value of water quality and a predetermined target value of water quality. A calculator for calculating the target value of the activated sludge microbial concentration according to, a controller for outputting the target value of the sludge extraction amount according to the deviation between the target value of the activated sludge microbial concentration and the measured value of the activated sludge microbial concentration The control device for an oxidation ditch water treatment device according to any one of claims 1 to 9, further comprising: adjusting means for adjusting the sludge withdrawal amount according to the target value of the sludge withdrawal amount. 11. A correction means for correcting the target value of the dissolved oxygen concentration from the measured value of the concentration of the activated sludge microorganisms measured at any point in the ditch or the target value of the activated sludge microorganisms concentration is provided. The control device of the oxidation ditch water treatment device according to claim 8 or 10. 12. A correction means for correcting the target value at the point where the dissolved oxygen concentration reaches the reference value from the measured value of the activated sludge microbial concentration measured at any point in the ditch or the target value of the activated sludge microbial concentration. The control device for an oxidation ditch water treatment device according to claim 9 or 10, wherein the control device is provided. 13. A means for measuring the quality of treated water, a controller for calculating a target value of sludge removal amount according to a deviation between a measured value of water quality and a predetermined target value of water quality, The control device for an oxidation ditch water treatment device according to any one of claims 1 to 12, further comprising adjusting means for adjusting an amount of sludge drawn out according to a target value. 14. A means for measuring at least one of water temperature, pH and redox potential installed at an arbitrary point in the ditch, and a correcting means for correcting the target value of the dissolved oxygen concentration from these measured values. Claims 8 and 1 characterized in that
The control device of the oxidation ditch water treatment apparatus according to any one of 0, 11, or 13. 15. A means for measuring at least one of water temperature, pH, and redox potential installed at an arbitrary point in a ditch, and a target value at a point where a reference value of dissolved oxygen concentration is reached from these measured values. The controller for an oxidation ditch water treatment device according to claim 9, 10, 12, or 13, further comprising a correcting means for correcting. 16. A means for measuring an inflow load to the ditch, and a means for calculating a feedforward amount of a reference value of the rotation speed or the immersion depth of the aeration device from the measured value of the inflow load. A control device for an oxidation ditch water treatment device according to any one of claims 1 to 15. 17. The activated sludge treatment is carried out by inflowing the water to be treated into a ditch by a mechanical aeration device provided in the ditch, and introducing the treated water from the ditch into a sedimentation basin. In the control device of the oxidation ditch water treatment device for performing solid-liquid separation, the means for measuring the outflow rate from the ditch, the above according to the deviation between the measured value of the outflow rate and the predetermined target value of the outflow rate. A controller for an oxidation ditch water treatment device, comprising: a controller that outputs a target value of the water level of the ditch; and a controller that adjusts the outflow rate according to the target value of the water level.