JP2003200190A - Device for controlling quality of water at sewage treatment plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To always maintain the quality of water of nitrogen and phosphor in treated water from a sewage treatment plant. <P>SOLUTION: Using a C/N ratio of a nitrogen component and organic substance components in incoming water flowing into the sewage treatment plant, at least one of the circulation rate, the returning rate, the amount of aeration air, the amount of carbon source poured, the flow rate of excessive sludge, the flow rate of returned water and an initial sedimentation by-path valve at the sewage treatment plant is controlled. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewage treatment plant water quality control device for controlling the quality of treated water discharged from a sewage treatment plant equipped with an aeration tank, and more particularly to nitrogen of inflow water flowing into the sewage treatment plant. Treated water discharged from the sewage treatment plant even when the water quality balance such as the ratio of the organic component to the organic component (C / N ratio) and the ratio of the phosphorus component to the organic component (C / P ratio) deteriorates The present invention relates to a water quality control device for a sewage treatment plant, which can always maintain good water quality of nitrogen and phosphorus.

[0002]

2. Description of the Related Art In recent years, eutrophication has been progressing in closed water areas such as lakes and bays, and it is necessary to suppress the outflow from the sewage treatment plants of nitrogen and phosphorus, which are the causative agents thereof, to the closed water areas. There is.

Therefore, in a conventional sewage treatment plant,
Organic substances have been removed by a process called the activated sludge method, but recently, due to the progress of eutrophication in closed water areas such as lakes, bays, etc., there is a demand for advanced treatment that also removes nitrogen and phosphorus. It is increasing.

Then, as a sewage treatment plant in order to meet such demand, a biological nitrification denitrification reaction, a biological dephosphorization reaction, a dephosphorization reaction by addition of a coagulant, etc. are utilized to flow into the sewage treatment plant. Sewage treatment plants equipped with aeration tanks that remove nitrogen or phosphorus in the inflow water have been realized.

FIG. 7 shows the above-mentioned various water treatment processes.
Flocculant injection type anaerobic-anoxic-aerobic method (Flocculant injection A
It is a flow chart showing an example of composition of a sewage treatment plant provided with an aeration tank constituted by a process called ₂ O method).

In FIG. 7, one of the inflow water 1 flowing into the sewage treatment plant first flows into the settling tank 2 via the water pipe 50 and the valve 24, and the anaerobic tank 10 via the water pipe 51. It flows into the anaerobic tank 10, which is an aeration tank composed of a combination of the oxygen-free tank 11 and the aerobic tank 12 provided with the aeration device 9.

The other one is a water pipe 50 and a water pipe 5.
9, flowing into the anaerobic tank 10 through the first settling bypass valve 23,
Water pipe 52, final settling tank 1 after treatment with aeration tank
3. The treated water 3 is discharged through the water pipe 60.

On the other hand, the carbon source is injected from the carbon source storage tank 21 into the anaerobic tank 10 through the carbon source injection pump 19 and the water pipe 57.

The coagulant is injected from the coagulant storage tank 22 into the aerobic tank 12 via the PAC injection pump 16 and the water pipe 56.

On the other hand, the untreated water in the aerobic tank 12 is the water pipe 5
3. Returned to the oxygen-free tank 11 via the circulation pump 14.

The settling water in the final settling tank 13 is returned to the anaerobic tank 10 via the water pipe 54 and the returning pump 15.

Furthermore, the final sludge water in the final settling tank 13 is
Through the water pipe 55 and the surplus pump 17, the sludge storage tank 20
Released to.

Furthermore, the first settling sludge water in the first settling tank 2 is discharged to the sludge storage tank 20 through the first settling / drawing pump 18 and the water pipe 58.

In the sewage treatment plant equipped with the aeration tank as described above, first, nitrogen is removed as follows.

In the aerobic tank 12, ammoniacal nitrogen (NH ₄ —N) is oxidized to nitrite nitrogen (NO ₂ —N) and nitrate nitrogen (NO ₃ —N) by the action of nitrifying bacteria.

The nitrite nitrogen (NO ₂ -N) and nitrate nitrogen (NO ₃ -N) sent into the anoxic tank 11 by the circulation pump 14 are deoxidized under the anoxic condition using organic matter as a nutrient source. It is reduced to nitrogen gas (N ₂ ) by nitrate respiration or nitrite respiration by nitrifying bacteria and is removed to the outside of the system.

At this time, if the organic substances necessary for the denitrification reaction are not sufficient, good nitrogen removal cannot be performed.

As a means for supplementing this organic substance,
By opening the initial settling bypass valve 23 and closing the valve 24, a method of bypassing the first settling tank 2 to secure organic substances, methanol, ethanol, acetic acid, waste acetic acid, glucose, etc. stored in the carbon source storage tank 21 There are a method of injecting a carbon source, a method of first introducing drawn sludge generated in the settling tank 2 into an aeration tank, and the like.

Next, phosphorus removal is performed by the following mechanism.

In the anaerobic tank 10 arranged in front of the aeration tank,
Phosphorus-accumulating bacteria in activated sludge accumulate organic acids such as acetic acid in the body, and phosphoric acid (PO ₄ ) is released.

The excessively released phosphate in the anaerobic tank 10 is released in the anaerobic tank 10 in the aerobic tank 12 arranged after the aeration tank by utilizing the phosphorus excessive intake action of phosphorus accumulating bacteria. Phosphorus is removed by absorbing phosphoric acid in activated sludge.

That is, in order to proceed such a reaction, an organic acid such as acetic acid is required as a hydrogen donor.

At the time of rainwater inflow, the concentration of organic acid becomes thin,
Since the amount of organic substances that can be used by the phosphorus accumulating bacteria is reduced, the sufficient phosphorus discharge reaction is not sufficiently performed, and the subsequent excessive phosphorus intake reaction is also insufficient.

To compensate for this, the carbon source necessary for phosphorus removal is secured by the same means as in the case of nitrogen removal, or polyaluminum chloride or aluminum sulfate stored in the flocculant storage tank 22 is secured. In order to remove phosphorus, a coagulant such as iron sulfate is injected to precipitate a phosphorus component in the form of aluminum phosphate or iron phosphate.

FIG. 8 is a block diagram showing one structural example of a conventional sewage treatment plant water quality control device.

In FIG. 8, the inflow water 1 flowing into the sewage treatment plant is of an aeration tank constituted by a combination of an oxygen-free tank 100 and an aerobic tank 101 equipped with an aeration device 103 via a water pipe 120. After flowing into the anoxic tank 100 and treated by the aeration tank, it is discharged as treated water 3 through the water pipe 121, the final settling tank 102, and the water pipe 122.

On the other hand, the untreated water in the aerobic tank 101 is returned to the anoxic tank 100 via the circulation pump 104.

Further, the settling water in the final settling tank 102 is passed through the water pipe 123 and the return pump 105 to obtain the oxygen-free tank 100.
Returned to.

On the other hand, the aerobic tank 101 is provided with an ammonia nitrogen concentration meter 106 for measuring the concentration of ammonia nitrogen, and the measured value 106a is output.

The control target value setter 108 sets the control target value 108a.

Further, in the controller 107, the measured value 106a from the ammonia nitrogen concentration meter 106 and the controller 10 are used.
The manipulated variable 107a for adjusting the aeration device 103 based on the deviation from the control target value 108a set by 7.
Is obtained and supplied to the aeration device 103.

As a result, control is performed so that the ammonia concentration in the aeration tank is kept constant.

[0033]

[Problems to be Solved by the Invention] (a) However,
As shown in FIG. 8, in the control in which the aeration air amount of the aeration device 103 is adjusted by feedback (FB) control based on the ammonia nitrogen concentration after nitrification treatment in the aerobic tank 101, it flows into the sewage treatment plant. Despite the large fluctuations in the amount of inflowing water, the water quality reaction by microorganisms in the aeration tank is relatively slow. Therefore, with such feedback control alone, the response of the water quality reaction to the change in the manipulated variable 107a is slow, and the treated water is treated. There is a problem that it is difficult to maintain good water quality.

(B) Further, only by controlling the nitrification reaction, nitrite nitrogen and nitrate nitrogen remain, the pH of the discharged water is lowered, and N ₂ gas generation due to the denitrification reaction occurs in the final settling tank. There is a problem of floating sludge.

In the denitrification, the circulation pump 104 is used to circulate the nitrification liquid in the anoxic tank 100 for denitrification. Conventionally, the circulation flow rate is controlled to be a constant amount or a ratio control to the inflow flow rate. In most cases,
Control is required for better denitrification.

On the other hand, in order to satisfactorily perform denitrification, it is necessary to secure a carbon source, and when the ratio (C / N ratio) of the nitrogen component to the organic matter component of the inflow water is reduced, There is a problem that the denitrification capacity decreases.

(C) Further, a nitrogen component concentration meter such as an ammonia nitrogen concentration meter, a nitrate nitrogen concentration meter, a total nitrogen concentration meter, etc. installed in the sewage treatment plant, and a phosphorus concentration meter, a total phosphorus concentration meter, etc. The component densitometer is liable to be contaminated due to floating components in the sewage and often shows an abnormal value, so that it is unstable as a control sensor, has low accuracy, and is difficult to use.

Even if the densitometer samples and filters, there is a problem in maintenance such as clogging of the sampling tube.

(D) Ratio of phosphorus component and organic component (C /
If P ratio is secured to some extent, it is possible to remove phosphorus to some extent only by biological dephosphorization, but C / P
If the ratio is small and the amount of usable organic matter for phosphorus-accumulating bacteria is small relative to the inflowing phosphorus, phosphorus must be secured by some means or by injecting a flocculant such as polyaluminum chloride unless phosphorus is used. Removal is difficult.

At this time, it has been empirically determined how much the carbon source should be injected, the cost due to the excessive injection of the coagulant, and the outflow of polyaluminum chloride into the treated water become problems. There is.

The object of the present invention is to determine the water quality such as the ratio of the nitrogen component to the organic component (C / N ratio), the ratio of the phosphorus component to the organic component (C / P ratio), etc. of the inflow water flowing into the sewage treatment plant. It is an object of the present invention to provide a sewage treatment plant water quality control device capable of always maintaining good water quality of nitrogen and phosphorus in treated water discharged from a sewage treatment plant even when the balance is deteriorated.

[0042]

In order to achieve the above-mentioned object, a sewage treatment plant water quality control device for controlling the quality of treated water discharged from a sewage treatment plant provided with an aeration tank, corresponds to claim 1. In the invention to do, a nitrogen component concentration measuring means for measuring the nitrogen component concentration of the inflow water flowing into the sewage treatment plant,
Based on the organic component concentration measuring means for measuring the organic component concentration of the inflow water flowing into the sewage treatment plant, and the nitrogen component concentration and the organic component concentration measured by the nitrogen component concentration measuring means and the organic component concentration measuring means, the sewage treatment Ratio of nitrogen component and organic matter component of inflow water flowing into the field (C / N
C / N ratio calculation means for calculating a ratio) and a reference C serving as a reference
C / N ratio setting means for setting the A / N ratio, and the reference C / N
Based on the difference between the reference C / N ratio set by the ratio setting means and the C / N ratio calculated by the C / N ratio calculating means,
A control means for outputting at least one of a circulation flow rate, a return flow rate, an aeration air flow rate, a carbon source injection amount, an excess sludge flow rate, a return water flow rate, and an initial settling bypass valve in a sewage treatment plant is provided. There is.

Therefore, in the sewage treatment plant water quality control apparatus of the invention according to claim 1, the C / N ratio of the inflow water flowing into the sewage treatment plant is calculated, and based on the difference from the reference C / N ratio. Inflow that flows into the sewage treatment plant by controlling at least one of the following: circulation flow rate, return flow rate, aeration flow rate, carbon source injection rate, excess sludge flow rate, return water flow rate, and first settling bypass valve Even when the water quality balance of the C / N ratio of water deteriorates, the quality of nitrogen in the treated water discharged from the sewage treatment plant is always maintained in good condition,
Nitrogen removal can be performed.

In the invention according to claim 2, the phosphorus component concentration measuring means for measuring the phosphorus component concentration of the inflow water flowing into the sewage treatment plant, and the organic component concentration of the inflow water flowing into the sewage treatment plant are measured. Based on the phosphorus component concentration and the organic component concentration measured by the organic component concentration measuring unit and the phosphorus component concentration measuring unit and the organic component concentration measuring unit, the phosphorus component and the organic component of the inflow water flowing into the sewage treatment plant C / P ratio calculation means for calculating a ratio (C / P ratio), C / P ratio setting means for setting a reference C / P ratio, and reference C / P set by the C / P ratio setting means Based on the difference between the P ratio and the C / P ratio calculated by the C / P ratio calculation means, the return flow rate at the sewage treatment plant, the aeration air volume,
And a control means for outputting an operation amount for controlling at least one of the carbon source injection amount, the coagulant injection amount, the excess sludge flow rate, the return water flow rate, and the initial settling bypass valve.

Therefore, in the sewage treatment plant water quality control apparatus according to the second aspect of the present invention, the C / P ratio of the inflow water flowing into the sewage treatment plant is calculated and based on the difference from the reference C / P ratio. Inflow to the sewage treatment plant by controlling at least one of the return flow rate at the sewage treatment plant, the amount of aeration air, the carbon source injection amount, the coagulant injection amount, the excess sludge flow amount, the return water flow amount, and the first settling bypass valve. Even when the water quality balance of the C / P ratio of the inflowing water is deteriorated, the phosphorus quality can be removed by always maintaining the good quality of phosphorus in the treated water discharged from the sewage treatment plant.

Further, in the invention corresponding to claim 3, the nitrogen component concentration measuring means for measuring the nitrogen component concentration of the inflow water flowing into the sewage treatment plant and the phosphorus component concentration of the inflow water flowing into the sewage treatment plant are measured. Phosphorus component concentration measuring means, organic component concentration measuring means for measuring the organic component concentration of the inflow water flowing into the sewage treatment plant, nitrogen component concentration measuring means and nitrogen component concentration and organic substance measured by the organic component concentration measuring means C / N ratio calculation means for calculating the ratio (C / N ratio) of nitrogen component and organic matter component of inflow water flowing into the sewage treatment plant based on the component concentration, phosphorus component concentration measurement means and organic matter component concentration measurement Based on the phosphorus component concentration and the organic component concentration measured by the means, the ratio (C / P) between the phosphorus component and the organic component of the inflow water flowing into the sewage treatment plant.
C / P ratio calculation means for calculating a ratio) and a reference C serving as a reference
A reference C / N ratio setting means for setting the A / N ratio, a C / P ratio setting means for setting a reference C / P ratio, and a reference C / N ratio.
The difference between the reference C / N ratio set by the N ratio setting means and the C / N ratio calculated by the C / N ratio calculating means, and C
Reference C / P ratio and C / P set by the / P ratio setting means
Based on the difference from the C / P ratio calculated by the ratio calculation means, the circulation flow rate, return flow rate, aeration air volume, carbon source injection rate, coagulant injection rate, excess sludge flow rate, return water flow rate in the sewage treatment plant Control means for outputting an operation amount for controlling at least one of the sinking bypass valve.

Therefore, in the sewage treatment plant water quality control apparatus of the invention according to claim 3, the C / N ratio of the inflow water flowing into the sewage treatment plant is calculated, and the C of the inflow water flowing into the sewage treatment plant is calculated. / P ratio is calculated and the difference from the reference C / N ratio,
And based on the difference from the standard C / P ratio, the circulation flow rate at the sewage treatment plant, the return flow rate, the aeration air volume, the carbon source injection volume,
By controlling at least one of the coagulant injection amount, excess sludge flow rate, return water flow rate, and first settling bypass valve, the water quality balance of C / N ratio and C / P ratio of inflow water flowing into the sewage treatment plant Even in the case where the water quality deteriorates, the quality of nitrogen and phosphorus in the treated water discharged from the sewage treatment plant can always be kept good, and nitrogen and phosphorus can be removed.

On the other hand, the quality of treated water discharged from a sewage treatment plant equipped with an aeration tank composed of an anoxic tank and an aerobic tank or a combination of an anaerobic tank, an anoxic tank and an aerobic tank is controlled. In the sewage treatment plant water quality control device, in the invention corresponding to claim 4, a nitrate nitrogen concentration measuring means for measuring the nitrate nitrogen concentration in the anoxic tank, and an organic matter component concentration of inflow water flowing into the anoxic tank. Based on the organic component concentration measuring means for measuring, the nitrate nitrogen concentration and the organic component concentration measured by the nitrate nitrogen concentration measuring means and the organic component concentration measuring means, the ratio (C /
C / N ratio calculating means for calculating N ratio, reference C / N ratio setting means for setting a reference C / N ratio as a reference, and reference C / N ratio
Based on the difference between the reference C / N ratio set by the N ratio setting means and the C / N ratio calculated by the C / N ratio calculating means, the circulation flow rate, return flow rate, aeration air amount, carbon source in the sewage treatment plant And a control means for outputting an operation amount for controlling at least one of the injection amount, the surplus sludge flow rate, the returning water flow rate, and the initial settling bypass valve.

Therefore, in the sewage treatment plant water quality control apparatus of the invention according to claim 4, the nitric acid is determined based on the concentration of nitrate nitrogen in the anoxic tank and the concentration of organic matter components of the inflow water flowing into the anoxic tank. C / N ratio between organic nitrogen and organic matter components is calculated, and based on the difference with the standard C / N ratio, the circulation flow rate, return flow rate, aeration air flow rate, carbon source injection rate, surplus sludge flow rate, return rate at the sewage treatment plant. Even if the water quality balance of the C / N ratio of the inflow water flowing into the sewage treatment plant is deteriorated by controlling at least one of the flow rate of the effluent and the first settling bypass valve, the effluent is discharged from the sewage treatment plant. Nitrogen can be removed while always maintaining good water quality of nitrogen in the treated water. It can also be applied to the case where the nitrate nitrogen concentration measuring means and the organic component concentration measuring means are not installed in the inflow part of the sewage treatment plant. Furthermore, by measuring the concentration in the aeration tank part, controllability can be improved. Can be further improved.

Further, in the invention according to claim 5, a phosphorus component concentration measuring means for measuring the phosphorus component concentration in the anaerobic tank, and an organic component concentration measuring means for measuring the organic component concentration of the inflow water flowing into the anaerobic tank. And a C / P ratio calculation for calculating the ratio (C / P ratio) between the phosphorus component and the organic substance component based on the phosphorus component concentration and the organic substance component concentration measured by the phosphorus component concentration measuring means and the organic substance component concentration measuring means. Means, a C / P ratio setting means for setting a reference C / P ratio, a reference C / P ratio set by the C / P ratio setting means, and a C calculated by the C / P ratio calculating means. Based on the difference with the / P ratio, the operation amount that controls at least one of the return flow rate at the sewage treatment plant, the aeration flow rate, the carbon source injection rate, the excess sludge flow rate, the return water flow rate, and the initial settling bypass valve is output. Control means to Eteiru.

Therefore, in the sewage treatment plant water quality control apparatus according to the fifth aspect of the invention, the phosphorus component and the organic substance are determined based on the phosphorus component concentration in the anaerobic tank and the organic component concentration of the inflow water flowing into the anaerobic tank. Calculate the C / P ratio with the components, and based on the difference from the standard C / P ratio, the return flow rate at the sewage treatment plant, the aeration air flow rate, the carbon source injection rate, the surplus sludge flow rate, the return water flow rate, the first settling bypass valve Even if the water quality balance of the C / P ratio of the inflow water that flows into the sewage treatment plant is deteriorated by controlling at least one of the above, the quality of phosphorus in the treated water discharged from the sewage treatment plant Can be maintained always good, and phosphorus can be removed. Also, it can be applied to the case where the phosphorus component concentration measuring means and the organic matter component concentration measuring means are not installed in the inflow part of the sewage treatment plant, and the controllability can be improved by measuring the concentration in the aeration tank part. It can be further improved.

Further, in the invention corresponding to claim 6, a nitrate nitrogen concentration measuring means for measuring the nitrate nitrogen concentration in the anoxic tank, and a phosphorus component concentration measuring means for measuring the phosphorus component concentration in the anaerobic tank. , Based on the nitrogen component concentration and the organic component concentration measured by the organic component concentration measuring device and the nitrogen component concentration measuring device and the organic component concentration measuring device for measuring the organic component concentration of the inflow water flowing into the sewage treatment plant Based on the C / N ratio calculating means for calculating the ratio (C / N ratio) of the component and the organic component and the phosphorus component concentration and the organic component concentration measured by the phosphorus component concentration measuring means and the organic component concentration measuring means, C / P ratio calculation means for calculating the ratio (C / P ratio) of the phosphorus component and organic matter component, reference C / N ratio setting means for setting a reference reference C / N ratio, and reference reference / A C / P ratio setting means for setting the P ratio, the reference C / N reference set by the ratio setting means C /
The difference between the N ratio and the C / N ratio calculated by the C / N ratio calculating means, and the reference C set by the C / P ratio setting means
/ P ratio and C / P ratio calculated by the C / P ratio calculation means, based on the difference between the circulation flow rate, return flow rate, aeration air volume, carbon source injection rate, excess sludge flow rate, and return water flow rate in the sewage treatment plant , And a control means for outputting an operation amount for controlling at least one of the initial sinking bypass valve.

Therefore, in the sewage treatment plant water quality control apparatus according to the sixth aspect of the present invention, the nitrogen content is adjusted based on the concentration of nitrate nitrogen in the oxygen-free tank and the concentration of the organic matter component of the inflow water flowing into the sewage treatment plant. The C / N ratio between the phosphorus component and the organic component is calculated, and the C / P of the phosphorus component and the organic component is calculated based on the phosphorus component concentration in the anaerobic tank and the organic component concentration of the inflow water flowing into the sewage treatment plant. The ratio is calculated, and based on the difference between the standard C / N ratio and the C / P ratio, the circulation flow rate, return flow rate, aeration flow rate, carbon source injection rate, excess sludge flow rate, return water flow rate at the sewage treatment plant By controlling at least one of the sedimentation bypass valves, even when the water quality balance of the inflow water flowing into the sewage treatment plant is deteriorated, the effluent is discharged from the sewage treatment plant. Treated water nitrogen, phosphorus water It can always be maintained satisfactorily performed nitrogen, phosphorus removal. It can also be applied to the case where the nitrate nitrogen concentration measuring means, phosphorus component concentration measuring means, and organic matter component concentration measuring means are not installed in the inflow part of the sewage treatment plant. By measuring, the controllability can be further improved.

On the other hand, in the invention corresponding to claim 7, any one of claim 1, claim 3, claim 4, and claim 6 is provided.
In the sewage treatment plant water quality control device of the invention corresponding to the item,
As a nitrogen component concentration measuring means, ammonia nitrogen concentration,
Or using a densitometer that measures either total nitrogen concentration,
In addition, as a means for measuring the concentration of organic components, biochemical oxygen demand (BOD), chemical oxygen demand (CODMn, CO
A densitometer for measuring either Dcr) or total organic carbon content (TOC) is used.

Therefore, in the sewage treatment plant water quality control apparatus of the invention according to claim 7, as the nitrogen component concentration measuring means, a concentration meter for measuring the ammonia nitrogen concentration and the total nitrogen concentration is used, and the organic substance component concentration is measured. As means, biochemical oxygen demand (BOD), chemical oxygen demand (CO
The net C / N ratio can be calculated by using a densitometer that measures DMn, CODcr) and total organic carbon content (TOC).

In the invention corresponding to claim 8, any one of claim 2, claim 3, claim 5, and claim 6 is provided.
In the sewage treatment plant water quality control device of the invention corresponding to the item,
As the phosphorus component concentration measuring means, a densitometer for measuring either phosphorus acid phosphorus concentration or total phosphorus concentration is used, and as the organic substance component concentration measuring means, biochemical oxygen demand (BO
D), chemical oxygen demand (CODMn, CODcr),
A densitometer that measures any of the total organic carbon (TOC) is used.

Therefore, in the sewage treatment plant water quality control apparatus according to the invention as claimed in claim 8, as the phosphorus component concentration measuring means, a concentration meter for measuring the phosphorus acid phosphorus concentration and the total phosphorus concentration is used, and the organic substance component concentration is measured. As means, biochemical oxygen demand (BOD), chemical oxygen demand (CODM)
The net C / P ratio can be calculated by using a densitometer that measures n, CODcr), and total organic carbon content (TOC).

Further, in the invention corresponding to claim 9, in the sewage treatment plant water quality control device of the invention according to any one of claims 1 to 8, ultraviolet rays of inflow water flowing into the sewage treatment plant are ultraviolet rays. An ultraviolet ray measuring unit for measuring (UV) intensity and a converting unit for converting the ultraviolet ray intensity into the organic component concentration based on the correlation between the ultraviolet intensity measured by the ultraviolet ray measuring unit and the organic component concentration are provided. The organic substance component concentration converted by the means is used instead of the organic substance component concentration measured by the organic substance component concentration measuring means.

Therefore, in the sewage treatment plant water quality control apparatus of the invention according to claim 9, the ultraviolet ray measuring means for measuring the ultraviolet ray (UV) intensity of the inflow water flowing into the sewage treatment plant is used, and the ultraviolet ray intensity is measured as an organic matter. By using the concentration of the organic component obtained by converting it into the component concentration, continuous measurement can be performed and the stability as a measuring means can be made high.

On the other hand, in the invention corresponding to claim 10, in the sewage treatment plant water quality control device according to any one of claims 1 to 9, the flow rate of the inflowing water flowing into the sewage treatment plant. Inflow water quality database that stores time-series data of water quality component measurement values by manual analysis, nitrogen component concentration measurement means, phosphorus component concentration measurement means, organic matter component concentration measurement means, ultraviolet ray measurement means, and inflow water quality Based on the time-series data stored in the database, equipped with inflow water quality prediction means for predicting at least one of nitrogen component concentration, phosphorus component concentration, and organic component concentration of inflow water flowing into the sewage treatment plant, Nitrogen component concentration, phosphorus component concentration predicted by the water quality prediction means,
The C / N ratio and the C / P ratio are calculated using the organic component concentration.

Therefore, in the sewage treatment plant water quality control apparatus according to the tenth aspect of the invention, each time series of the flow rate of the inflowing water flowing into the sewage treatment plant, the measured value of the water quality component, and the water quality test result by manual analysis is obtained. Based on the data, at least one of the nitrogen component concentration, the phosphorus component concentration, and the organic matter component concentration of the inflow water that flows into the sewage treatment plant is predicted, and the predicted value is used to calculate the C / N ratio, C / When it is difficult to install the nitrogen component concentration measuring means, the phosphorus component concentration measuring means, the organic component concentration measuring means by calculating the P ratio, or the nitrogen component concentration measuring means, the phosphorus component concentration measuring means, the organic component concentration measuring means Even in the case of failure, the control can be sufficiently performed.

Further, in the invention corresponding to claim 11, in the sewage treatment plant water quality control device according to any one of claims 1 to 10, the flow rate of inflowing water flowing into the sewage treatment plant. The flow rate measuring means for measuring the flow rate is used as the control means, and the flow rate value measured by the flow rate measuring means and the reference C / N set by the reference C / N ratio setting means are provided.
The difference between the ratio and the C / N ratio calculated by the C / N ratio calculation means, and the reference C / set by the C / P ratio setting means.
Based on the difference between the P ratio and the C / P ratio calculated by the C / P ratio calculation means, the circulation flow rate, return flow rate, aeration air volume, carbon source injection rate, excess sludge flow rate, return water flow rate in the sewage treatment plant, The operation amount for controlling at least one of the initial sink bypass valves is output.

Therefore, in the sewage treatment plant water quality control apparatus according to the eleventh aspect of the present invention, the flow rate measuring means for measuring the flow rate of the inflowing water flowing into the sewage treatment plant is used, and the flow rate measurement value by the flow rate measuring means, Based on the difference between the standard C / N ratio and the C / N ratio, and the difference between the standard C / P ratio and the C / P ratio, the circulation flow rate, return flow rate, aeration flow rate, carbon source injection rate at the sewage treatment plant, By controlling at least one of the surplus sludge flow rate, return water flow rate, and first settling bypass valve, in the case where the quality of the treated water varies depending on the size of the inflow of inflow to the sewage treatment plant. Also,
The controllability can always be kept good.

Further, in the invention corresponding to claim 12,
In the sewage treatment plant water quality control device of the invention according to any one of claims 1 to 11, at least one of water quality components of the treated water after passing through the aeration tank or the treated water in the aeration tank is measured. Water quality measuring means and a control correcting means for correcting the operation amount output from the control means based on the difference between the measured value of the water quality component measured by the water quality measuring means and the preset target value of the water quality component. It is attached.

Therefore, in the sewage treatment plant water quality control device of the invention according to claim 12, the water quality component of the treated water after passing through the aeration tank or the treated water in the aeration tank is measured, and the measured value of the water quality component is measured. By correcting the operation amount output from the control unit based on the difference between the target value of the water quality component and the target value of the water quality component, the water quality of the treated water can always be kept good.

[0066]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing an example of the structure of a water quality control system for a sewage treatment plant according to this embodiment. The same parts as those in FIG. 7 are designated by the same reference numerals. Description is omitted, and only different parts will be described here.

That is, as shown in FIG. 1, the sewage treatment plant water quality control apparatus according to the present embodiment has the TOC meter 4 as the organic component concentration measuring means and the ammonia component concentration measuring means as shown in FIG. A densitometer 5, a C / N ratio calculator 6, a reference C / N ratio setter 7, and a controller 8 are added.

The valve 24 and the water pipe 5 shown in FIG.
9. The first settling bypass valve 23 is not shown in FIG.

The TOC meter 4 is installed in the water pipe 51 and measures the total organic carbon content (TOC) 4a, which is the concentration of organic substances in the influent 1 flowing into the sewage treatment plant.

The ammonia concentration meter 5 is installed in the same water pipe 51 and measures the total nitrogen concentration 5a, which is the concentration of nitrogen components in the inflow water 1 flowing into the sewage treatment plant.

The C / N ratio calculation unit 6 calculates the nitrogen component of the inflow water 1 flowing into the sewage treatment plant based on the total organic carbon amount 4a and the total nitrogen concentration 5a measured by the TOC meter 4 and the ammonia concentration meter 5. Ratio of organic matter and organic components (C / N ratio) 6
Calculate a.

The reference C / N ratio setter 7 sets a reference C / N ratio 7a as a reference.

Based on the difference between the reference C / N ratio 7a set by the reference C / N ratio setting unit 7 and the C / N ratio 6a calculated by the C / N ratio calculation unit 6, the control unit 8 calculates The operation amount 8a for adjusting the flow rate of the carbon injection pump 19 in the sewage treatment plant is output.

Next, the operation of the sewage treatment plant water quality control apparatus according to the present embodiment configured as described above will be described.

In FIG. 1, the total organic carbon amount (TOC) 4a, which is the measured value of the TOC meter 4 installed on the water pipe 51 that first flows into the aeration tank from the settling tank 2, and the measurement of the total nitrogen meter 5. The total nitrogen concentration 5a, which is the value, is input to the C / N ratio calculator 6 via the signal lines 4a and 5a, and C / N ratio is calculated based on these.
The N ratio is calculated.

An arithmetic expression in this case is represented by the following expression (1.1), for example.

[0078]

[Equation 1]

P _CN : C / N ratio at time t C _TOC : TOC concentration of inflow water, C _TN : Total nitrogen concentration of inflow water The C / N ratio calculated by the above equation (1.1) is calculated on the signal line 6a. It is input to the control unit 8 via the.

On the other hand, the reference C / N ratio setter 7 sets the reference C / N ratio.

In the controller 8, based on the deviation between the C / N ratio calculated by the C / N ratio calculator 6 and the reference C / N ratio, the target carbon source injection amount is, for example, the following formula (1. The carbon source injection amount is adjusted so that the carbon source injection amount target value is calculated by the equation shown in the equation (2).

[0082]

[Equation 2]

SVQ _{carbon, t} : Target carbon source injection amount at time t _{PCN , t} : C / N ratio at time t P _Cnbase : Reference C / N ratio for efficient nitrogen removal Q _in : Sewage treatment Field inflow rate C _carbonTOC : TOC concentration of carbon source C _{T-Nin, t} : T-N concentration of inflow water On the other hand, reference C set by reference C / N ratio setting device 7
Although the value of / N ratio P _Cnbase varies depending on the target sewage treatment plant, in order to perform efficient nitrogen removal, BOD
Since it is necessary to secure 3 to 4 as the / t-N ratio, it is preferable to set a value of about 4 to 6 in consideration of the BOD / TOC ratio.

TOC concentration of carbon source C _carbonTOC is the carbon source used (methanol, ethanol, acetic acid, waste acetic acid,
If glucose etc) and the concentration of the solution are known, it can be easily determined.

The carbon source injection amount is adjusted according to the carbon source injection amount target value calculated by the above equation (1.2).

By the water quality control device of this sewage treatment plant, C /
The necessary amount of carbon source can be injected only when the N ratio is decreased, that is, when the amount of organic matter required for efficient nitrogen removal is insufficient, and efficient nitrogen removal without excessive injection of carbon source is achieved. Can be done.

As described above, the sewage treatment plant water quality control system according to this embodiment can obtain the following effects.

(A) Since the carbon source injection pump 19 is used as the control target, C corresponding to the injection amount is used.
The / N ratio can be easily calculated, and it is possible to maintain a value equal to or higher than the C / N ratio required for efficient nitrogen removal without injecting an excessive carbon source.

(B) Since the TOC meter 4 is used as the sensor for measuring the organic component and the total nitrogen meter 5 is used as the sensor for measuring the nitrogen component, it is possible to calculate the net organic substance and the nitrogen ratio. Becomes

(C) All parameters can be calculated by setting the reference C / N ratio P _Cnbase by the reference C / N ratio setting device 7, so that parameter adjustment is not necessary.

(D) Since the total nitrogen meter 5 and TOC meter 4 are arranged in the water pipe 51 after the first settling tank 2, the water pipe 50
The possibility of sensor value abnormality due to dirt is reduced as compared with the case of arranging in the above, and the net C / N ratio flowing into the aeration tank can be calculated.

(Modification 1) The nitrogen component concentration meter 5 and the organic substance concentration meter 4 in FIG.
It may be attached to 0.

Any position can be used as long as it is the first settling basin 2, the inflow basin, the sand basin, the pump well, etc., as long as it is a front stage part of the aeration tank.

(Modification 2) As the organic component concentration meter 4 in FIG. 1, any of a BOD meter and a COD meter may be used instead of the TOC meter.

Even if the nitrogen component concentration meter 5 is not a total nitrogen meter, most of the nitrogen components of the inflow water 1 flowing into the sewage treatment plant are ammonia nitrogen. It may be used.

(Modification 3) As the nitrogen component concentration meter 5 of FIG. 1, a nitrate nitrogen meter mounted in the oxygen-free tank 11 may be used.

(Modification 4) Examples of the carbon source include methanol, ethanol, acetic acid, waste acetic acid and glucose.

Further, the drawn sludge of the first settling tank 2 in FIG. 1 and the fermented sludge may be used.

(Modification 5) As the operation amount 8a calculated by the control unit 8 in FIG. 1, in addition to the carbon source injection amount, the circulation flow rate, the return flow rate, the aeration air amount, the carbon source injection amount, the surplus sludge flow rate, and the return amount. It may be either a flowing water flow rate or a first settling bypass valve.

For example, when the manipulated variable 8a calculated by the control unit 8 is the circulation flow rate, the target value is calculated by the arithmetic expression as shown in the following formula (1.3), for example.

[0101]

[Equation 3]

SVQ _{cir, t} : Target value of carbon source injection amount at time t P _{CN, t} : C / N ratio at time t P _Cnbase : C / N ratio for efficient nitrogen removal Q0: Constant K: proportional The constant Q0 may be a constant flow rate or a target value for ratio control with respect to the inflow rate.

Thus, when the C / N ratio is insufficient, the circulation flow rate is controlled to increase, and when the C / N ratio is sufficient, the circulation flow rate is controlled to decrease, so that nitrogen can be removed efficiently. be able to.

(Modification 6) The manipulated variable 8a calculated by the control unit 8 in FIG. 1 is not limited to the one described above, but may be a plurality of controlled variables.

For example, when the carbon source injection amount and the return water flow rate are selected as the manipulated variable 8a calculated by the control unit 8, the C / N ratio is set by the reference C / N ratio setting unit 7. If it is larger than the value, the return water flow rate is controlled as shown in the following formula (1.4), and the C / N ratio is higher than the value set by the reference C / N ratio setter 7. If it is small, the injection amount of the carbon source is the above formula (1.
It is controlled in the form shown in 2).

It is also possible to carry out switching control by combining in this way.

That is, the return water returned from the sludge storage tank 20 has a higher nitrogen load and a smaller C / N ratio than the inflow water flowing from the sewer pipe. Therefore, when the return water amount is increased, It acts to lower the C / N ratio.

When the C / N ratio is large, the control target value is calculated for the larger amount of returned water.

When the C / N ratio becomes smaller, the control target value is calculated for the smaller amount of returned water.

[0110]

[Equation 4]

SVQ _{cir, t} : Carbon source injection amount target value at time t P _CN : C / N ratio at time t P _Cnbase : Reference C / N ratio T _I : Integration time Q0: Constant K: Proportional constant C / N When the ratio is smaller than the value set by the reference C / N ratio setting device 7 and the carbon source is insufficient, the amount of return water goes toward zero, and becomes zero when P _{CN, t} <P _Cnbase. .

On the other hand, when P _{CN, t} <P _Cnbase , the carbon source injection amount _tends to increase as described above.

Further, instead of the above switching control,
It is also possible to control two or more manipulated variables at the same time.

(Modification 7) The target process may be applied to any of the following water treatment processes.

Standard activated sludge method A ₂ O method (anaerobic-anoxic-aerobic method) AO method (anaerobic-aerobic method) Nitrification Endogenous denitrification method Circulating nitrification denitrification method OD method Step injection method Batch activated sludge method Intermittent aeration method Carrier injection type activated sludge method carrier injection A ₂ O method carrier injection AO method carrier injection Nitrification endogenous denitrification method carrier injection Cycle type nitrification denitrification method carrier injection OD method carrier injection step injection method carrier injection batch type activated sludge method carrier Input intermittent aeration method Flocculant injection type activated sludge method Flocculant injection A ₂ O method Flocculant injection AO method Flocculant injection Nitrification Endogenous denitrification method Flocculant injection Circulating nitrification denitrification method Flocculant injection Step OD method Flocculant injection Flocculant injection Batch activated sludge method Flocculant injection Intermittent aeration method Membrane separation type activated sludge method Membrane separation type A ₂ O method Membrane separation type AO method Membrane separation type Nitrification Endogenous denitrification method Membrane separation circulation type Nitrification denitrification method Membrane separation Type OD method Membrane separation type step injection method Membrane separation type batch Activated sludge process membrane separation type intermittent aeration method In addition to the above, the carrier is turned, the process of the flocculant combination type or AOAO method, may be used in any variation of the various A ₂ O process.

(Modification 8) The manipulated variable 8a calculated by the control unit 8 in FIG. 1 is the time when the C / N ratio of the influent 1 flowing into the sewage treatment plant is calculated and until it flows into the aeration tank. In consideration of the time lag of, the following expression (1.5) may be used.

[0117]

[Equation 5]

SVQ _{carbon, t} : Target value of carbon source injection amount at time t P _CN : C / N ratio at time t P _Cnbase : Reference C / N ratio Q _{in, t-Δt} : Sewage treatment plant at time t-Δt Inflow rate C _carbonTOC : TOC concentration of carbon source C _{T-Nin, t} : Total nitrogen concentration of inflow water at time t-Δt (Modification 9) Direct measurement of organic matter concentration of inflow water 1 flowing into the sewage treatment plant Even if not, ultraviolet rays (UV)
Ultraviolet rays (UV) measured by a UV meter that measures intensity
A conversion value obtained by obtaining the concentration of the organic component of the inflow water 1 flowing into the sewage treatment plant may be used from the correlation between the strength and the concentration of the organic component.

For example, it is said that the chemical oxygen demand (COD) value generally has a high correlation with the UV value, and the CO value can be calculated by the equation shown in the following equation (1.6).
The D value can be estimated.

[0120]

[Equation 6]

C _COD : Estimated value of COD C _UV : UV measured value a, b: Constant As a result, even in a sewage treatment plant where an organic component concentration meter such as a COD meter is not installed, contamination of water to be treated, etc. UV is a more stable sensor that is not easily affected by
Control can be performed using the measurement value of the meter.

(Modification 10) The output of the manipulated variable 8a calculated by the control unit 8 in FIG. 1 is the deviation ( _{PCN, t-} P).
It does not have to be linearly proportional to _CNbase ), but may be anything based on the deviation.

For example, the logarithm of the deviation log (P _{CN, t} −P
_CNbase ), exponential function exp (P _{CN, t} −P
_CNbase ), a power proportional to the power (P _{CN, t} −P _CNbase ) ⁿ , or a combination thereof.

(Modification 11) The C / N ratio is not calculated from the measured values of the organic component concentration meter 4 and the nitrogen component concentration meter 5, but is predicted using the past inflow water quality pattern. It may be calculated using the predicted value.

(Modification 12) It is possible to correct the ratio of the flow rate ratio control to the inflow rate of the inflow water 1 flowing into the sewage treatment plant, or to correct the control target value of the DO control.

(Modification 13) In addition to the C / N ratio calculator 6 of FIG. 1, a C / P ratio calculator is provided, and circulation is performed based on the C / N ratio and C / P ratio calculated by these. At least one of the flow rate, the return flow rate, the aeration flow rate, the carbon source injection rate, the coagulant injection rate, the excess sludge flow rate, and the return water flow rate may be adjusted.

(Modification 14) The water quality attached to the portion where the biological water treatment is almost completed, such as the rear part of the aerobic tank 12 of FIG. 1, the water pipe 52, the final settling tank 13, the water pipe 60 and the like. By feedback (FB) control using a sensor,
The control amount may be corrected.

(Second Embodiment) FIG. 2 is a block diagram showing a structural example of a water quality control system for a sewage treatment plant according to this embodiment. The same parts as those in FIG. 7 are designated by the same reference numerals. Description is omitted, and only different parts will be described here.

That is, as shown in FIG. 2, the sewage treatment plant water quality control apparatus according to the present embodiment has the TOC meter 4 as the organic component concentration measuring means and the total phosphorus component concentration measuring means shown in FIG. A phosphorus densitometer 25, a C / P ratio calculator 6 ', a reference C / P ratio setter 7', and a controller 8 are added.

The valve 24 and the water pipe 5 shown in FIG.
9, the first settling bypass valve 23 is not shown in FIG.

The TOC meter 4 is installed in the water pipe 51 and measures the total organic carbon content (TOC) 4a, which is the concentration of organic substances in the influent 1 flowing into the sewage treatment plant.

The total phosphorus concentration meter 25 is installed in the same water pipe 51 and measures the total phosphorus concentration 25a which is the phosphorus component concentration of the inflow water 1 flowing into the sewage treatment plant.

The C / P ratio calculation unit 6'according to the total organic carbon amount 4a and the total phosphorus concentration 25a measured by the TOC meter 4 and the total phosphorus concentration meter 25, the inflow water 1 flowing into the sewage treatment plant is calculated. Ratio of phosphorus component and organic component (C / P ratio)
6'a is calculated.

The reference C / P ratio setter 7'sets a reference C / P ratio 7'a as a reference.

The control unit 8 includes a reference C / P ratio 7'a set by the reference C / P ratio setting unit 7'and a C / P ratio calculation unit 6 '.
Based on the difference with the C / P ratio 6′a calculated by
The operation amount 8a for adjusting the flow rate of the PAC injection pump 16 in the sewage treatment plant is output.

Next, the operation of the sewage treatment plant water quality control apparatus according to the present embodiment configured as described above will be described.

In FIG. 2, the total organic carbon content (TOC) 4a, which is the measured value of the TOC meter 4 installed on the water pipe 51 that first flows into the aeration tank from the settling tank 2, and the total phosphorus meter 2
The total phosphorus concentration 25a, which is the measured value of 5, is measured by the signal lines 4a, 2
It is input to the C / P ratio calculation unit 6'through 5a, and the C / P ratio is calculated based on these.

An arithmetic expression in this case is represented by the following expression (2.1), for example.

[0139]

[Equation 7]

P _{CP, t} : C / P ratio at time t C _TOC : inflow water TOC concentration, C _TP : total inflow water phosphorus concentration C / P ratio calculated by the above equation (2.1) is the signal line It is input to the control unit 8 via 6a '.

On the other hand, by the reference C / P ratio setter 7 ',
The reference C / P ratio is set.

In the control unit 8, based on the deviation between the C / P ratio calculated by the C / P ratio calculation unit 6'and the reference C / P ratio,
The PAC injection amount target value is calculated, for example, by the formula shown in the following formula (2.2), and the PAC flow rate is adjusted so as to be the PAC injection amount target value.

[0143]

[Equation 8]

SVQ _{PAC, t} : Target value of PAC injection amount at time t P _CP : C / P ratio at time t P _Cnbase : Reference C / P ratio Q0: Constant K: Proportional constant The constant of Q0 is a constant flow rate. Alternatively, the target value of the ratio control with respect to the inflow rate may be used.

The value of the reference C / P ratio P _CPbase set by the reference C / P ratio setting device 7 ′ varies depending on the target sewage treatment plant, but in order to perform efficient simultaneous removal of phosphorus nitrogen, Since it is necessary to secure a BOD / TP ratio of about 25, it is preferable to set a value of about 30 to 45 in consideration of the BOD / TOC ratio.

By the water quality control device of this sewage treatment plant, C /
When the P ratio is small, the efficiency of biological phosphorus removal is lowered, so that the injection amount of PAC tends to increase, and conversely, when the C / P ratio is large, the injection amount of PAC decreases. Head in the direction.

As described above, the sewage treatment plant water quality control apparatus according to this embodiment can obtain the following effects.

(A) Since the PAC injection pump 16 is used as the control target, even if the C / P ratio is low and biological phosphorus removal is difficult, the phosphorus concentration of the discharged water quality is not deteriorated. It becomes possible to remove phosphorus.

(B) Since the TOC meter 4 is used as the sensor for measuring the organic component and the total phosphorus meter 25 is used as the sensor for measuring the phosphorus component, the net organic substance,
It is possible to calculate the phosphorus ratio.

(C) If the reference C / P ratio setter _{7'sets the} reference C / P ratio P _CPbase , the parameter is K
And Q0, which are as small as two, making it possible to adjust parameters relatively easily.

(D) Since the total phosphorus total 25 and the TOC total 4 are first arranged in the water pipe 51 after passing through the sedimentation tank 2, the water pipe 5
Compared with the case of setting it to 0, the possibility of sensor value abnormality due to dirt is reduced and the net C / P flowing into the aeration tank is reduced.
It is possible to calculate the ratio.

(Modification 1) The phosphorus component concentration meter 25 of FIG.
The organic component concentration meter 4 may be attached to the water pipe 50.

Any position can be used as long as it is the first settling basin 2, the inflow basin, the sand basin, the pump well, etc., as long as it is a front stage part of the aeration tank.

(Modification 2) As the organic component concentration meter 4 in FIG. 2, any of a BOD meter and a COD meter may be used instead of the TOC meter.

Even if the phosphorus component concentration meter 25 is not the total phosphorus concentration meter, most of the phosphorus component of the inflow water 1 flowing into the sewage treatment plant is phosphorus acid phosphorus, so the phosphorus acid concentration meter 25 It may be used.

(Modification 3) As the total phosphorus meter 25 shown in FIG. 2, a phosphorus acid phosphorus meter mounted in the anaerobic tank 10 may be used.

(Modification 4) As the manipulated variable 8a calculated by the control unit 8 of FIG. 2, in addition to the PAC (coagulant) injection amount, the return flow rate, the aeration air flow rate, the carbon source injection rate, the surplus sludge flow rate, and the return flow rate. It may be any of the running water flow rates.

(Modification 5) As the manipulated variable 8a calculated by the control unit 8 in FIG. 2, not only one described above but one may be controlled.

(Modification 6) The target process may be applied to any of the water treatment processes described above.

Further, it may be used in any of a carrier injection method, a coagulant combination type process, and various A ₂ O methods such as AOAO method.

(Variation 7) The manipulated variable 8a calculated by the control unit 8 in FIG. 2 is the time when the C / P ratio of the inflow 1 flowing into the sewage treatment plant is calculated and until it flows into the aeration tank. The time lag of may be taken into consideration.

(Modification 8) Ultraviolet (UV) intensity measured by a UV meter for measuring ultraviolet (UV) intensity, even if the concentration of organic components in the influent 1 flowing into the sewage treatment plant is not directly measured. And the correlation between the organic component concentration,
A conversion value obtained by obtaining the concentration of the organic matter component of the inflow water 1 flowing into the sewage treatment plant may be used.

(Modification 9) The C / P ratio is not calculated from the measured values of the organic component densitometer and the nitrogen component densitometer, but the predicted value predicted by the method described later is used. May be (Invention of Claim 10) (Modification 10) The output of the manipulated _variable 8a calculated by the control unit 8 of FIG. 2 is not necessarily linearly proportional to the deviation (P _{CN, t} −P _CNbase )) Anything based on

For example, the logarithm of the deviation log (P _{CN, t} −P
_CNbase ), exponential function exp (P _{CN, t} −P
_CNbase ), a power proportional to the power (P _{CN, t} −P _CNbase ) ⁿ , or a combination thereof.

(Modification 11) Even if the C / P ratio is not calculated from the respective measured values of the organic component concentration meter 4 and the phosphorus component concentration meter 25, it is predicted using the past inflow water quality pattern and the like. It may be calculated using the predicted value.

(Modification 12) It is possible to correct the ratio of the flow ratio control to the inflow of the inflow 1 flowing into the sewage treatment plant, or to correct the control target value of the DO control.

(Modification 13) C / P ratio calculator 6'of FIG.
In addition to the above, a C / N ratio calculator is provided, and based on the C / N ratio and C / P ratio calculated by these, the circulation flow rate, the return flow rate, the aeration air volume, the carbon source injection volume, the coagulant injection volume, At least one of the excess sludge flow rate and the return water flow rate may be adjusted.

(Variation 14) The quality of water attached to the portion where the biological water treatment is almost completed, such as the rear stage of the aerobic tank 12 of FIG. 2, the water pipe 52, the final settling tank 13 and the water pipe 60. By feedback (FB) control using a sensor,
The control amount may be corrected.

(Third Embodiment) FIG. 3 is a block diagram showing a structural example of a water quality control system for a sewage treatment plant according to this embodiment. The same parts as those in FIG. Description is omitted, and only different parts will be described here.

That is, as shown in FIG. 3, the sewage treatment plant water quality control apparatus according to the present embodiment has a UV meter 30 as an ultraviolet ray measuring means, a flowmeter 31 as a flow rate measuring means, as shown in FIG. NH ₄ meter 32, T-N meter 33 which is a nitrogen component concentration measuring means, and T-N which is a phosphorus component concentration measuring means.
P total 34, inflow water quality database 26, meteorological information prediction unit 27, inflow water quality pattern database 28, inflow water quality prediction unit 29, reference C / N ratio C / P ratio setter 7 ″.
A UV → BOD converter 37, a C / N ratio C / P ratio calculation unit 6 ″, an inflow ratio setting unit 38, a control unit 8, a treated water quality determination unit 36, and a control correction unit 35 are added. It has been configured.

The valve 24 and the water pipe 5 shown in FIG.
9, the initial precipitation bypass valve 23, the carbon source storage tank 21, the carbon source injection pump 19, and the water pipe 57 are omitted in FIG. 3.

The UV meter 30 is installed in the water pipe 51, and ultraviolet rays (UV) of the inflow water 1 flowing into the sewage treatment plant.
Measure the strength.

The flow meter 31 is installed in the same water pipe 51 and measures the flow rate of the inflow water 1 flowing into the sewage treatment plant.

The NH ₄ meter 32 is installed in the aerobic tank 12 and measures the concentration of ammonia in the aerobic tank 12.

The TN meter 33 is installed in the water pipe 61 and measures the total nitrogen concentration of the treated water 3.

The T-P meter 34 is installed in the same water pipe 61 and measures the total phosphorus concentration of the treated water 3.

The inflow water quality database 26 is a UV meter 30.
Total phosphorus concentration measured measured ultraviolet (UV) intensity, the ammonia concentration was measured by NH ₄ meter 32, the total nitrogen concentration was measured by T-N meter 33, the T-P meter 34, the flow meter 31 The time-series data of the flow rate measured by and the water quality test result by manual analysis which is a daily water quality test are stored.

The weather information predicting section 27 predicts weather information.

The inflow water quality pattern database 28 creates and stores inflow water quality patterns based on the data accumulated in the inflow water quality database 26.

The inflow water quality prediction unit 29 flows into the sewage treatment plant based on the TN water quality pattern stored in the inflow water quality pattern database 28 and the weather information predicted by the weather information prediction unit 272. At least one of the nitrogen component concentration, the phosphorus component concentration, and the organic substance component concentration of the inflow water is predicted.

The reference C / N ratio C / P ratio setter 7 ″ sets the reference C / N ratio and the reference C / P ratio.

The UV → BOD converter 37 converts the ultraviolet (UV) intensity measured by the UV meter 30 into a biochemical oxygen demand (BOD).

The C / N ratio C / P ratio calculation unit 6 ″ includes a nitrogen component concentration, a phosphorus component concentration, an organic component concentration predicted by the inflow water quality prediction unit 29, and an N ratio C / P ratio reference setter 7 ″. The standard C / N ratio and standard C / P ratio set by
The C / N ratio and the C / P ratio are calculated based on the BOD converted by the BOD converter 37.

The inflow ratio setter 38 determines the aeration air flow rate, the circulation flow rate, the PA flow rate with respect to the flow rate of the inflow water 1 flowing into the wastewater treatment plant.
Set the ratio of the C injection flow rate.

The control unit 8 has a C / N ratio C / P ratio calculation unit 6 ".
C / N ratio, C / P ratio and C / N ratio C / P calculated by
Based on the deviations of the reference C / N ratio and the reference C / P ratio set by the ratio reference setting device 7 ″, the operation amount for adjusting the aeration device 9, the circulation pump 14, and the PAC injection pump 16 is output.

The treated water quality judging unit 36 determines the ammonia concentration measured by the NH ₄ meter 32, the total nitrogen concentration measured by the TN meter 33, and the total phosphorus concentration measured by the TP meter 34. Based on this, the water quality state of the treated water 3 is determined.

The control correction unit 35 controls the control unit 8 based on the difference between the water quality state of the treated water 3 determined by the treated water quality determination unit 36 and the preset target value of the water quality component.
The manipulated variables for the aeration device 9, the circulation pump 14, and the PAC injection pump 16 output from are corrected.

Next, the operation of the sewage treatment plant water quality control apparatus according to the present embodiment having the above-described structure will be described with reference to the relationship diagrams shown in FIGS. 4 to 6.

In FIG. 3, the first settling tank 2 to the anaerobic tank 1
UV meter 3 mounted on water pipe 51 connected to 0
The UV intensity, which is the measured value of 0, is converted from UV to BOD 3
Converted to BOD value by 7 and C /
It is input to the N ratio C / P ratio calculation unit 6 ″.

The nitrogen component concentration and the phosphorus component concentration, which are the inflow water quality of the inflow water 1 flowing into the sewage treatment plant, are estimated by the following method.

The inflow water quality database 26 contains time series data of water quality measured by daily water quality tests and the flowmeter 3.
The time series data of the flow rate measurement value of 1 and the UV measurement value of the UV meter 30 is held.

[0192]

[Table 1]

The inflow water quality pattern database 28 contains
Meteorological information such as weather, rainfall, rainfall duration, rainfall intensity, temperature, etc., and inflow water quality patterns are stored for each day event such as season, weekday, and Sunday.

This is created from the data accumulated in the inflow water quality database 26, and this inflow water quality pattern can be freely changed by the operator of the sewage treatment plant.

For example, FIG. 4 is a diagram showing inflow TN fluctuation patterns on weekdays, summers, and sunny days.

The water quality pattern of TN has a peak in the morning as shown in FIG.

The water quality pattern of TP also has a peak in the morning.

Note that, in FIG. 4, the circle marks are data stored in the inflow water quality database 26.

The inflow water quality prediction unit 29 selects a similar day based on the day event of the day and the weather information predicted by the weather information prediction unit 27, and the TN water quality pattern of the day is selected from the water quality pattern database 28. Be done.

In this case, if the T-
When N is measured and the value is input to the inflow water quality database 26, different TN water quality patterns are selected based on the data, as shown in FIG. 5, and the daily variation pattern is corrected. .

Further, the similar date is re-searched by the data accumulated in the inflow water quality database 26 such as the measurement value of the flow meter 31 and the measurement value of the UV meter 30, and the daily fluctuation pattern is updated at any time.

The T− predicted by the inflow water quality predicting unit 29
The N concentration and the T-P concentration are C / N ratio C / P via the signal line.
It is input to the ratio calculation unit 6 ″.

C / N ratio In the C / P ratio calculation unit 6 ″, the C / N ratio and C / N ratio are calculated based on the following formulas (3.1) and (3.2).
Each P ratio is calculated.

[0204]

[Equation 9]

P _{CN, t} : C / N ratio at time t C _BOD : Influent water BOD concentration conversion value, C _TN : Influent water total nitrogen concentration predicted value

[Equation 10]

P _{CP, t} : C / P ratio at time t C _BOD : Influent water BOD concentration conversion value, C _TP : Influent water total phosphorus concentration predicted value On the other hand, by the inflow ratio setting unit 38, the aeration air volume with respect to the inflow flow rate, Circulation flow rate, ratio of PAC injection flow rate Rblow, R
cir and Rpac are set respectively.

The C / N ratio C / P ratio calculation unit 6 ″
Based on the respective deviations of the C / N ratio and C / P ratio calculated by the reference C / N ratio and the reference C / N ratio and the reference C / P ratio set by the C / P ratio setter 7 ″. Thus, the ratio of the circulation flow rate and the PAC injection amount to the inflow flow rate is corrected.

[0208]

[Equation 11]

SVQ _{blow, t} : Aeration air flow rate target value SVQ _{cir, t} : Circulation flow rate target value SVQ _{pac, t} : PAC flow rate target value Q _{in, t} : Inflow rate P _{CNbase at} time t: Reference C / N ratio P _CPbase : Reference C / P ratio Sblow, Scir, Spac: Control correction amount K1, K2: Constant

[0210]

[Equation 12]

C _{NH4, t} : Concentration of ammonia nitrogen at time t C _{TN, t} : Concentration of total nitrogen at time t C _{TP, t} : Concentration of total phosphorus at time t K3, K4, K5: Constant The above equation (3.3). ) -Equation (3.5), the circulation flow rate increases when the C / N ratio is insufficient, and the PAC injection amount increases when the C / P ratio is insufficient.

The control correction amount (Sblow, Scir, Spac) is
It is calculated by the following equations (3.6) to (3.8).

On the basis of the count value of the TN meter 33, the count value of the TP meter 34, and the count value of the NH ₄ meter 32 attached to the pipe 60 after passing through the final settling tank 13, the treated water 3 was treated. The treated water quality determination unit 36 that determines the water quality state causes TN,
When it is determined that the T-P process tends to deteriorate, the correction is applied.

That is, for example, as shown in FIGS. 6A to 6C, (1) when the measured values of the TN meter 33 and the TP meter 34 are continuously increasing (see FIG. a)), (2) T
When the measured values of the -N meter 33 and the T-P meter 34 are equal to or higher than the processing deterioration determination value and a certain time has passed (FIG. 6B), (3) T
When the measured values of the -N meter 33 and the T-P meter 34 have a sharp increase in concentration within a certain time width (Fig. 6 (c)), it is determined that the quality of the treated water 3 has deteriorated. To be done.

From the above, the treated water quality judgment unit 36
When it is determined that the treated water has deteriorated, the control amount is corrected by the following logic.

(1) Treated water TN deteriorates, and aerobic tank 12
When the measured value by the NH ₄ meter 32 in the above is higher than a certain reference value, the aeration air flow rate is corrected by, for example, the above formula (3.6).

(2) Treated water T-N deteriorates and treated water T-N
When the difference between the measured value of the N meter 33 and the measured value of the NH ₄ meter 32 in the aerobic tank 12 is equal to or more than a certain value, it is determined that the denitrification process is defective, and for example, the above formula (3.7) is used. The circulation flow rate is corrected by.

(3) When the treated water T-P deteriorates,
For example, the PAC flow rate is corrected by the above equation (3.8).

As described above, the sewage treatment plant water quality control apparatus according to the present embodiment can obtain the following effects.

(A) Since the predicted values are used as the nitrogen component concentration and the phosphorus component concentration of the inflow water 1 flowing into the sewage treatment plant, the nitrogen component concentration meter and the phosphorus component concentration meter should not be installed. It will be possible to apply it even at various machines.

(B) Instead of the organic component concentration meter, a UV meter 30 capable of continuous measurement with relatively high accuracy is used to measure the organic component concentration, so that more effective control is possible. Can be carried out.

(C) Since the manipulated variable is corrected by feedback (FB) control using the measured values of total nitrogen and total phosphorus in the discharged water quality, the quality of the treated water 3 is not deteriorated. It becomes possible to control.

(D) The ammonia meter 32 attached to the aerobic tank 12 determines whether the deterioration of the total nitrogen in the treated water 3 is due to poor nitrification or poor denitrification, and the aeration air volume and circulation Since the flow rate is controlled, it is possible to perform more efficient nitrogen removal.

(Modification 1) Flowmeter 31 and U in FIG.
The V meter 30 may be attached to the water pipe 50.

The first settling basin 2, the inflow basin, the sand basin, the pump well, etc. can be used at any position as long as it is in the front stage of the aeration tank.

Further, instead of the flow meter 31, it is also possible to use one in which the flow rate is calculated by the QH curve from the measured value of the water level gauge installed in the pump well.

(Modification 2) Instead of the ultraviolet (UV) intensity, the measurement value of a densitometer for directly measuring the organic component may be used as the organic component concentration.

(Modification 3) As the phosphorus component concentration and the nitrogen component concentration of the inflow water 1 flowing into the sewage treatment plant, the water pipes 50, 51, the first settling basin 2, the inflow basin, the sand basin, the pump well, etc. are aerated. T-P meter attached to the front part of the tank, PO ₄
Meter and T-N meter, may be utilized a measurement of NH ₄ meters.

(Modification 4) The water pipes 50, 51, the first settling basin 2, the inflow basin, the sand basin, the pump well, etc., and the TP meter, the PO ₄ meter, the TN meter, and the NH at the front stage of the aeration tank. _{Even in} a sewage treatment plant where _four gauges are installed, control may be performed using the value predicted by the inflow water quality pattern prediction.

(Modification 5) As the operation amount 8a calculated by the control unit 8 in FIG. 1, the circulation flow rate, the return flow rate, the aeration air flow rate, the carbon source injection rate, the coagulant injection rate, the excess sludge flow rate, and the return water flow rate. At least one of the first settling bypass valve may be provided.

(Modification 6) TN meter 3 of treated water 3 in FIG.
3 and the mounting position of the T-P meter 34 include a water pipe 6
Even if the position is not 0, the rear part of the aerobic tank 12 and the water pipe 5
2. Any position may be used as long as the biological water treatment is almost completed, such as the final sedimentation tank 13.

(Modification 7) As a nitrogen component concentration meter 5 for measuring the nitrogen component of the treated water 3 for control correction, a TN meter 3 is used.
Instead of 3, the concentration may be any one of ammonia nitrogen concentration, nitrate nitrogen concentration, and nitrite nitrogen concentration, and the correction may be performed using a plurality of concentrations instead of one.

(Modification 8) A T-P meter 34 is used as a phosphorus component concentration meter for measuring the phosphorus component of the treated water 3 for control correction.
Alternatively, the concentration of phosphoric acid and phosphorus may be used, and a plurality of corrections may be used instead of one.

(Modification 9) The control correction is attached to the rear stage of the aerobic tank 12, the water pipe 52, the final settling tank 13, the water pipe 60, and the like where the biological water treatment is almost completed. DO meter, ORP meter, pH meter, SS meter, MLSS meter, UV
Any of a water quality sensor such as a meter may be used.

(Modification 10) The operation amount output calculated by the control unit 8 of FIG. 3 is not necessarily linearly proportional to the deviation as shown above, but may be any operation based on the deviation. It may be one.

For example, it may be one proportional to the logarithm of the deviation, one exponential function, one proportional to a power, or a combination thereof.

(Modification 11) The output from the control correction unit 35 may be any output based on the deviation, not necessarily linearly proportional to the deviation.

For example, it may be one proportional to the logarithm of the deviation, one exponential function, one proportional to the power, or a combination thereof.

(Other Embodiments) The present invention is not limited to the above-described embodiments, but can be variously modified and implemented at the stage of implementation without departing from the spirit of the invention. Is. For example, in the above embodiments,
The case where the present invention is applied to a sewage treatment plant equipped with an aeration tank composed of a combination of an anaerobic tank, an anoxic tank, and an aerobic tank has been described, but the present invention is not limited to this, and an anoxic tank and an aerobic tank are provided. The present invention can be applied to the sewage treatment plant including the aeration tank constituted by the combination of the above, and the same effects can be obtained by applying the present invention as described above.

Further, the respective embodiments may be combined as appropriate as much as possible, and in that case, the combined effects can be obtained. Further, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent features. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, the problem (at least one) described in the section of the problem to be solved by the invention can be solved, and When the effect (at least one) described in the section can be obtained, a structure in which this constituent element is deleted can be extracted as an invention.

[0241]

As described above, according to the sewage treatment plant water quality control apparatus of the present invention, the C / N ratio between the nitrogen component and the organic component of the inflow water or / and the C ratio between the phosphorus component and the organic component. Circulation flow rate in the sewage treatment plant using the / P ratio,
At least one of the return flow rate, aeration flow rate, carbon source injection rate, excess sludge flow rate, return water flow rate, and first settling bypass valve is controlled, so that the nitrogen component of the inflow water flowing into the sewage treatment plant Even when the water quality balance such as the C / N ratio with the organic component and the C / P ratio with the phosphorus component and the organic component is deteriorated, the water quality of nitrogen and phosphorus of the treated water discharged from the sewage treatment plant is always maintained. It becomes possible to remove nitrogen and phosphorus while maintaining good condition.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a water quality control device for a sewage treatment plant according to the present invention.

FIG. 2 is a block diagram showing a second embodiment of the water quality control device for a sewage treatment plant according to the present invention.

FIG. 3 is a block diagram showing a third embodiment of the water quality control device for a sewage treatment plant according to the present invention.

FIG. 4 is a relationship diagram for explaining the operation of the sewage treatment plant water quality control device according to the third embodiment.

FIG. 5 is a relationship diagram for explaining the operation of the water quality control device for a sewage treatment plant according to the third embodiment.

FIG. 6 is a relationship diagram for explaining the operation of the sewage treatment plant water quality control device according to the third embodiment.

FIG. 7 is a flow diagram showing a configuration example of a sewage treatment plant including an aeration tank configured by a coagulant injection type anaerobic-anoxic-aerobic method (coagulant injection A ₂ O method).

FIG. 8 is a block diagram showing a configuration example of a conventional sewage treatment plant water quality control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inflow water 2 ... First settling basin 3 ... Treated water 4 ... TOC meter 5 ... TN meter 6 ... C / N ratio calculation unit 6 '... C / P ratio calculation unit 6 "... C / N ratio, C / P ratio calculator 7 ... Standard C / N ratio setter 7 '... Standard C / P ratio setter 7 "... Standard C / N ratio, C / P ratio setter 8 ... Controller 9 ... Aerator 10 ... Anaerobic tank 11 ... Anoxic tank 12 ... Aerobic tank 13 ... Final settling tank 14 ... Circulation pump 15 ... Return pump 16 ... PAC injection pump 17 ... Surplus pump 18 ... Initial sinking / pulling pump 19 ... Carbon source injection pump 20 ... Sludge storage tank 21 ... Carbon source storage tank 22 ... Flocculant storage tank 23 ... First settling bypass valve 24 ... Valve 25 ... TP total 26 ... Inflow water quality database 27 ... Meteorological information prediction unit 28 ... Water quality pattern database 29 ... Inflow water quality prediction unit 30 ... UV meter 31 ... flow meter 32 ... NH ₄ meter 33 ... T-N in total 34 ... T-P total 35 ... control correction unit 6 ... treated water determination unit 37 ... UV → BOD terms 38 ... inflow ratio setter 50 to 60 ... water pipe.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 3/34 101 C02F 3/34 101C G05D 21/00 G05D 21/00 A (72) Inventor Rin Yamanaka Tokyo No. 1 in Toshiba Town, Fuchu, Tokyo (72) Inventor Yuio Motoki 1-1-1, Shibaura, Minato-ku, Tokyo Tokyo Head Office Office (72) Inventor Yoshihiro Shibamoto Shibaura, Minato-ku, Tokyo 1-1-1 1-1 Toshiba Headquarters Office (72) Inventor Yukio Hatsuka 1-1-30 Oyodochu, Kita-ku, Osaka-shi, Osaka F-Term (1) 1-30, Kansai Branch of Toshiba Corporation (reference) 4D028 AA08 CA00 CA09 CA12 CB03 CC01 CC02 CE02 4D040 BB05 BB07 BB25 BB57 BB65 BB72 BB91 BB93 5H309 AA07 BB20 CC05 DD08 DD13 DD14 DD37 DD38 EE03 GG02 HH12 JJ06

Claims (12)

[Claims] 1. A sewage treatment plant water quality control device for controlling the quality of treated water discharged from a sewage treatment plant equipped with an aeration tank, wherein a nitrogen component for measuring a nitrogen component concentration of inflow water flowing into the sewage treatment plant. Concentration measuring means, organic component concentration measuring means for measuring the organic component concentration of the inflow water flowing into the sewage treatment plant, nitrogen component concentration and organic component measured by the nitrogen component concentration measuring means and the organic component concentration measuring means C / N ratio calculating means for calculating the ratio (C / N ratio) of the nitrogen component and the organic matter component of the inflow water flowing into the sewage treatment plant based on the concentration, and the reference C / N ratio to be set Reference C / N ratio setting means, and the reference C / N ratio set by the reference C / N ratio setting means
The circulation flow rate in the sewage treatment plant based on the difference between the ratio and the C / N ratio calculated by the C / N ratio calculation means,
Control means for outputting an operation amount for controlling at least one of the return flow rate, the aeration flow rate, the carbon source injection rate, the surplus sludge flow rate, the return water flow rate, and the initial settling bypass valve. Sewage treatment plant water quality control device. 2. A sewage treatment plant water quality control device for controlling the quality of treated water discharged from a sewage treatment plant provided with an aeration tank, wherein a phosphorus component for measuring a phosphorus component concentration of inflow water flowing into the sewage treatment plant. Concentration measuring means, organic component concentration measuring means for measuring organic component concentration of inflow water flowing into the sewage treatment plant, phosphorus component concentration and organic component measured by the phosphorus component concentration measuring means and organic component concentration measuring means C / P ratio calculation means for calculating the ratio (C / P ratio) between the phosphorus component and the organic matter component of the inflow water flowing into the sewage treatment plant based on the concentration, and a reference C / P ratio to be set C / P ratio setting means for performing the sewage treatment based on the difference between the reference C / P ratio set by the C / P ratio setting means and the C / P ratio calculated by the C / P ratio calculating means. At the processing plant Control means for outputting an operation amount for controlling at least one of the return flow rate, the amount of aeration air, the injection amount of carbon source, the injection amount of coagulant, the flow rate of excess sludge, the return water flow rate, and the initial settling bypass valve. A sewage treatment plant water quality control device characterized by the above. 3. A sewage treatment plant water quality control device for controlling the quality of treated water discharged from a sewage treatment plant provided with an aeration tank, wherein a nitrogen component for measuring a nitrogen component concentration of inflow water flowing into the sewage treatment plant. Concentration measuring means, phosphorus component concentration measuring means for measuring phosphorus component concentration of inflow water flowing into the sewage treatment plant, and organic component concentration measuring means for measuring organic component concentration of inflow water flowing into the sewage treatment plant Based on the nitrogen component concentration and the organic component concentration measured by the nitrogen component concentration measuring means and the organic component concentration measuring means, the ratio (C / N) between the nitrogen component and the organic component of the inflow water flowing into the sewage treatment plant. C / N ratio calculating means for calculating the ratio), and based on the phosphorus component concentration and the organic component concentration measured by the phosphorus component concentration measuring means and the organic component concentration measuring means. A C / P ratio calculating means for calculating a ratio (C / P ratio) between a phosphorus component and an organic matter component of the inflow water flowing into the sewage treatment plant; and a reference C / N for setting a reference C / N ratio. N ratio setting means, C / P ratio setting means for setting a reference C / P ratio, and reference C / N set by the reference C / N ratio setting means
The difference between the ratio and the C / N ratio calculated by the C / N ratio calculation means, and the reference C / P ratio set by the C / P ratio setting means and the C / P ratio calculation means Based on the difference with the C / P ratio, among the circulation flow rate, return flow rate, aeration flow rate, carbon source injection rate, coagulant injection rate, excess sludge flow rate, return water flow rate, first settling bypass valve in the sewage treatment plant A sewage treatment plant water quality control device comprising: a control unit that outputs an operation amount that controls at least one. A water quality control device for a sewage treatment plant, comprising: a control unit for controlling one or more of the above. 4. The quality of treated water discharged from a sewage treatment plant equipped with an aeration tank composed of an anoxic tank and an aerobic tank or an anaerobic tank, an anoxic tank and an aerobic tank is controlled. In a sewage treatment plant water quality control device, a nitrate nitrogen concentration measuring means for measuring a nitrate nitrogen concentration in the anoxic tank, and an organic component concentration measuring means for measuring an organic component concentration of inflow water flowing into the anoxic tank And based on the nitrate nitrogen concentration and the organic component concentration measured by the nitrate nitrogen concentration measuring unit and the organic component concentration measuring unit, the ratio (C /
C / N ratio calculation means for calculating N ratio), reference C / N ratio setting means for setting a reference C / N ratio as a reference, and reference C / N set by the reference C / N ratio setting means.
The circulation flow rate in the sewage treatment plant based on the difference between the ratio and the C / N ratio calculated by the C / N ratio calculation means,
Control means for outputting an operation amount for controlling at least one of the return flow rate, the aeration flow rate, the carbon source injection rate, the surplus sludge flow rate, the return water flow rate, and the initial settling bypass valve. Sewage treatment plant water quality control device. 5. Sewage for controlling the quality of treated water discharged from a sewage treatment plant having an aeration tank composed of an anaerobic tank and an aerobic tank, or a combination of an anaerobic tank, an anoxic tank and an aerobic tank. In the treatment plant water quality control device, a phosphorus component concentration measuring unit that measures the phosphorus component concentration in the anaerobic tank, an organic component concentration measuring unit that measures the organic component concentration of the inflow water flowing into the anaerobic tank, and the phosphorus component Based on the phosphorus component concentration and the organic component concentration measured by the concentration measuring unit and the organic component concentration measuring unit, the ratio between the phosphorus component and the organic component (C / P ratio)
C / P ratio calculation means for calculating, C / P ratio setting means for setting a reference C / P ratio, reference C / P ratio set by the C / P ratio setting means, and C / P ratio Based on the difference with the C / P ratio calculated by the P ratio calculating means, of the return flow rate, the aeration air flow rate, the carbon source injection rate, the surplus sludge flow rate, the return water flow rate, and the initial sedimentation bypass valve in the sewage treatment plant. A sewage treatment plant water quality control device comprising: a control unit that outputs an operation amount that controls at least one. 6. A sewage treatment plant water quality control device for controlling the quality of treated water discharged from a sewage treatment plant, comprising an aeration tank composed of a combination of an anaerobic tank, an anoxic tank, and an aerobic tank. Nitrate nitrogen concentration measuring means for measuring the nitrate nitrogen concentration in the anoxic tank, phosphorus component concentration measuring means for measuring the phosphorus component concentration in the anaerobic tank, and organic matter components of inflow water flowing into the sewage treatment plant Based on the organic component concentration measuring means for measuring the concentration and the nitrogen component concentration and the organic component concentration measured by the nitrogen component concentration measuring means and the organic component concentration measuring means, the ratio (C / N) between the nitrogen component and the organic component ratio)
Based on the phosphorus component concentration and the organic component concentration measured by the phosphorus component concentration measuring unit and the organic component concentration measuring unit, the ratio (C / P) between the phosphorus component and the organic component is calculated. ratio)
C / P ratio calculating means for calculating, a reference C / N ratio setting means for setting a reference C / N ratio, and a C / P ratio setting means for setting a reference C / P ratio, Reference C / N set by the reference C / N ratio setting means
The difference between the ratio and the C / N ratio calculated by the C / N ratio calculation means, and the reference C / P ratio set by the C / P ratio setting means and the C / P ratio calculation means Control at least one of the circulation flow rate, return flow rate, aeration flow rate, carbon source injection rate, excess sludge flow rate, return water flow rate, and first settling bypass valve in the sewage treatment plant based on the difference from the C / P ratio A sewage treatment plant water quality control device comprising: 7. The sewage treatment plant water quality control device according to claim 1, wherein the nitrogen component concentration measuring means is ammoniacal nitrogen concentration, Alternatively, a densitometer for measuring any of the total nitrogen concentration is used, and as the organic component concentration measuring means, biochemical oxygen demand (BOD), chemical oxygen demand (CODM)
n, CODcr), or a total concentration of organic carbon (TOC), a densitometer is used for the sewage treatment plant water quality control device. 8. The sewage treatment plant water quality control device according to any one of claims 2, 3, 5, and 6, wherein the phosphorus component concentration measuring means is a phosphorus acid phosphorus concentration,
A densitometer for measuring any of the total phosphorus concentrations is used, and as the organic component concentration measuring means, biochemical oxygen demand (BOD), chemical oxygen demand (CODM)
n, CODcr), or a total concentration of organic carbon (TOC), a densitometer is used for the sewage treatment plant water quality control device. 9. The method according to any one of claims 1 to 8.
In the sewage treatment plant water quality control device according to the item 1, an ultraviolet ray measuring means for measuring an ultraviolet ray (UV) intensity of the inflow water flowing into the sewage treatment plant, and an ultraviolet ray intensity and an organic component concentration measured by the ultraviolet ray measuring means. Based on the correlation of, the conversion means for converting the ultraviolet intensity to the organic component concentration, and the organic component concentration converted by the conversion means, instead of the organic component concentration measured by the organic component concentration measuring means A water quality control device for a sewage treatment plant, which is characterized by being used for. 10. The sewage treatment plant water quality control device according to claim 1, wherein a flow rate of inflowing water flowing into the sewage treatment plant, the nitrogen component concentration measuring means, and a phosphorus component. Concentration measuring means, organic matter component concentration measuring means, measured value of water quality component by ultraviolet ray measuring means, and inflow water quality database that stores time series data of water quality test results by manual analysis, and time series data stored in the inflow water quality database Based on, the inflow water quality predicting means for predicting at least one of the nitrogen component concentration, the phosphorus component concentration, and the organic matter component concentration of the inflow water flowing into the sewage treatment plant, is predicted by the inflow water quality predicting means. Nitrogen concentration,
Using the phosphorus component concentration and the organic component concentration, the C / N
A water quality control device for a sewage treatment plant, wherein a ratio and a C / P ratio are calculated. 11. The sewage treatment plant water quality control device according to claim 1, further comprising a flow rate measuring unit that measures a flow rate of inflow water flowing into the sewage treatment plant, The control means includes a flow rate value measured by the flow rate measuring means, a reference C / N ratio set by the reference C / N ratio setting means, and a C / N ratio calculated by the C / N ratio calculating means. And the difference between the reference C / P ratio set by the C / P ratio setting means and the C / P ratio calculated by the C / P ratio calculating means, based on the circulating flow rate in the sewage treatment plant. , Return flow rate, aeration flow rate, carbon source injection rate, surplus sludge flow rate, return water flow rate, and operation amount for controlling at least one of the first settling bypass valve are output. Control device. 12. The sewage treatment plant water quality control device according to claim 1, wherein the treated water after passing through the aeration tank or the water quality component of the treated water in the aeration tank is used. At least one water quality measuring unit to measure, based on the difference between the measured value of the water quality component measured by the water quality measuring unit and the preset target value of the water quality component, the operation amount output from the control unit. A water quality control device for a sewage treatment plant, comprising: