JP3376620B2 - Biological denitrification treatment apparatus and biological denitrification treatment method - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a biological denitrification treatment apparatus.
And a biological denitrification treatment method , in particular, in batch-type biological denitrification treatment of nitrogen-containing wastewater in a single biological treatment tank, by effectively controlling the aeration amount of the biological treatment tank. ,
The present invention relates to a biological denitrification treatment apparatus and a biological denitrification treatment method that make it possible to stably obtain treated water of high quality.

[0002]

2. Description of the Related Art As a method for treating wastewater containing nitrogen such as human waste, batch biological dewatering in which raw water is intermittently introduced into a single biological treatment tank and a nitrification process and a denitrification process are alternately performed. There is a treatment method.

In this batch-type biological denitrification treatment system, raw water is introduced into a biological treatment tank at regular intervals, and
The inside of the tank is aerated to perform nitrification and aerobic denitrification, and then the aeration is stopped, and the denitrification is performed by injecting an organic substance and stirring to complete one batch treatment.

Conventionally, the control of the amount of aeration in such batch processing is performed based on the dissolved oxygen (DO) in the biological treatment tank. That is, in the conventional aeration amount control method, the aeration amount that reaches a predetermined DO within a certain period of time is set as a standard, and when the standard is not reached, the next aeration amount is increased; when it reaches earlier than the standard, the next aeration amount is set. Lowering;

FIG. 2 shows an example of changes over time in ORP (oxidation-reduction potential) and DO and N (nitrogen) concentration in the biological treatment tank in the batch-type biological denitrification treatment.

[0006]

The DO meter is not suitable as an index for controlling the aeration amount because it is greatly affected by dirt, deterioration of the meter, or the property of sludge, and the indicated value is unstable. There are cases.

The present invention solves the above-mentioned conventional problems and performs batch-type biological denitrification treatment of nitrogen-containing wastewater in a single biological treatment tank based on the ORP of the aeration amount of the biological treatment tank. Biological denitrification treatment equipment and biological denitrification for effective setting or control to stably obtain high quality treated water
It is intended to provide a raw material processing method .

[0008]

[Means for Solving the Problems]Claim 1Biological denitrification
The elementary treatment device comprises a treatment tank for receiving nitrogen-containing wastewater,
Means for intermittently introducing nitrogen-containing wastewater into the treatment tank,
The means for discharging the treated water from the treatment tank to the outside of the tank and the inside of the treatment tank are
Equipped with aeration means for aeration, it is a batch type of nitrification and denitrification.
In the biological denitrification treatment apparatus, the ORP in the treatment tank
And a detection ORP of the measurement means.
Aeration amount that sets the aeration amount for the next batch processing based on the value
Control means providedA biological denitrification treatment device comprising:
The aeration amount control means uses the time-dependent change curve of ORP in the treatment tank.
The shape near the maximum value of ORP in
Compared with the shape near the maximum value of the ORP change pattern,
If the hill shape is gentler than that of the standard ORP,
Excessive aeration. Sharp angle compared to the standard ORP
If it is, the aeration is insufficient. Almost the same as the standard ORP
If the shape, the aeration is appropriate. And judge each
In the case of the above, the aeration amount in the next batch processing is
If the amount is less than the aeration amount and in the above case, the next batch processing
The amount of aeration in is larger than this time, and
In the case of, the aeration amount in the next batch process
Set the aeration amount for the next time so that it is about the same as the air amount.
It is a volume control meansIt is characterized by

[0009]The biological denitrification treatment apparatus according to claim 2,
A treatment tank that receives elemental-containing wastewater, and a nitrogen-containing treatment tank
Means to intermittently add wastewater and treated water from the treatment tank
Means for discharging outside the tank and aeration means for aerating the inside of the processing tank
And a batch-type biological denitrification treatment for nitrification and denitrification.
Measuring device for measuring ORP in the processing tank
A step is provided, and based on the detected ORP value of the measuring means,
Biological aeration amount control means for controlling the aeration amount during separation treatment
A denitrification treatment device, wherein the aeration amount control means is a treatment tank.
The rise curve of the time-dependent change of ORP in the
Compared to the rise curve of ORP, (i) Soaring after that of the standard ORP and after that
If it follows a moderate rise, it is over-aeration. (ii) Those that rise linearly compared to those of the standard ORP
If so, there is insufficient aeration. (iii) If the rising curve is almost the same as the reference ORP, it is suitable.
Normal aeration. It is judged respectively, and in the case of (i) above,
In the case of (ii) above, increase the aeration amount so as to reduce the aeration amount.
In the case of (iii) above, the amount of aeration as it is
Exposure to control the amount of aeration during the batch process to maintain
It is characterized by being a volume control means.

The biological denitrification treatment method according to claim 3 is
A treatment tank that receives elemental-containing wastewater, and a nitrogen-containing treatment tank
Means to intermittently add wastewater and treated water from the treatment tank
Means for discharging outside the tank and aeration means for aerating the inside of the processing tank
And a batch-type biological denitrification treatment for nitrification and denitrification.
Biological denitrification treatment method for treating nitrogen-containing wastewater with a processing device
Method, the ORP in the treatment tank is measured and detected.
Biology that sets the aeration amount for the next batch processing based on the value
Denitrification treatment method, in which the ORP in the treatment tank changes over time.
The shape near the maximum value of the ORP in the conversion curve is set in advance.
Shape and ratio in the vicinity of the maximum value of the change pattern of the standard ORP
Compared to the standard ORP, it has a gentle hill shape
If so, excessive aeration. Compared to the standard ORP
If the shape is sharp, the aeration is insufficient. Standard ORP
If the shape is almost the same, proper aeration is performed. And each judgment
The aeration amount in the next batch treatment in the above case.
Is less than the aeration amount this time, and in the above case,
The aeration amount in batch processing is larger than this time's.
In the above case, the aeration amount in the next batch treatment
Set the aeration amount for the next time so that it is about the same as this time.
It is characterized by setting.

[0011]The biological denitrification treatment method according to claim 4,
A treatment tank that receives elemental-containing wastewater, and a nitrogen-containing treatment tank
Means to intermittently add wastewater and treated water from the treatment tank
Means for discharging outside the tank and aeration means for aerating the inside of the processing tank
And a batch-type biological denitrification treatment for nitrification and denitrification.
Biological denitrification treatment method for treating nitrogen-containing wastewater with a processing device
Method, the ORP in the treatment tank is measured and detected.
Batch processing based on the value Biological control of physical aeration rate
This is a denitrification treatment method and changes with time of ORP in the treatment tank.
Of the rising curve of the standard ORP with the preset rising curve of the reference ORP.
Compare (i) Soaring after that of the standard ORP and after that
If it follows a moderate rise, it is over-aeration. (ii) Those that rise linearly compared to those of the standard ORP
If so, there is insufficient aeration. (iii) If the rising curve is almost the same as the reference ORP, it is suitable.
Normal aeration. It is judged respectively, and in the case of (i) above,
In the case of (ii) above, increase the aeration amount so as to reduce the aeration amount.
In the case of (iii) above, the amount of aeration as it is
Exposure to control the amount of aeration during the batch process to maintain
It is characterized by being a volume control means.

[0012]

The present inventor conducted a study to control the amount of aeration in a batch type biological denitrification process using a single tank based on ORP, and as a result, the time course of ORP in the processing tank was As shown in Fig. 2, it temporarily drops from human waste input, rises during the subsequent aeration time, reaches a maximum after the addition of methanol (organic matter), and then falls again; and it is effective under the proper aeration amount. It was found that the ORP change curve in the case of performing nitrification and denitrification treatment has a constant pattern.

In addition, the ORP change when the aeration amount is excessive and the ORP change when the aeration amount is insufficient with respect to the ORP reference change when effective treatment is performed. As shown in FIG. 3 and FIG. 4, which is an enlarged view of the portion of FIG. 3, it was confirmed that the patterns were different.

That is, as shown in FIGS. 3 and 4A and 4C, the ORP at the time of over-aeration is compared with the reference ORP.
When the ORP rises from the minimum value ORP _min, the rise is fast, the change in ORP after that is small, and the slope of the curve reaching the maximum value ORP _max of the ORP after the addition of methanol (organic substance) is small. Then, _{ORP ma x} at this time
The neighboring curve has a gentle hill shape, and ORP _max
Is smaller than the _max of the reference ORP.

Further, as shown in FIGS. 3 and 4A and 4B, the ORP in the case of insufficient aeration is higher than that of the reference ORP.
Minimum ORP value ORP _min to maximum ORP value ORP
_The curve that reaches _max is linear. Then, show substantially the same value as the _{ORP max} of _{ORP max} Criteria ORP of this _time, the curve of _{ORP max} vicinity becomes pointed acute angle.

Therefore, in one batch process, the change in the ORP in the processing tank is investigated, and the shape near the maximum value is compared with the shape near the maximum value of the preset reference ORP change pattern to obtain the reference ORP. If the hill shape is gentler than that of the above, it is excessive aeration. If the shape is sharper than that of the reference ORP, the aeration is insufficient. If the shape is almost the same as the reference ORP, proper aeration is performed. In the above case, the aeration amount in the next batch process is smaller than the current aeration amount, in the above case, the aeration amount in the next batch process is larger than the current aeration amount, and In the case of, by setting the aeration amount of the next time so that the aeration amount in the next batch processing is about the same as the aeration amount of this time, it is possible to compensate for the excess or deficiency of the aeration and perform good processing. Like

Further, the ORP rising curve during the aeration period is compared with the rising curve of the reference ORP. (I) Excess aeration is performed as long as it follows a rapid increase and a gentle increase thereafter as compared with the reference ORP. is there. (ii) If it rises linearly compared to that of the standard ORP, the aeration is insufficient. (iii) If the rising curve is almost the same as the reference ORP, the aeration is appropriate. In the case of (i) above, reduce the aeration amount, in the case of (ii) increase the aeration amount, and in the case of (iii), maintain the same aeration amount. As described above, by controlling the aeration amount during the aeration period, the excess or deficiency of the aeration amount is corrected during the aeration period,
Good processing can be performed.

As described above, in the conventional control of the aeration amount by DO, the aeration amount that reaches a predetermined DO within a certain time is standard, and when it does not reach the standard, the next aeration amount is increased; If reached, reduce the next aeration amount;
Is the method. This control method determines the amount of aeration for the next time from the processing status of the current time, and since the amount of aeration is constant during the aeration period, it is determined whether the amount of aeration is appropriate during aeration. Therefore, the adequacy of the aeration amount will be determined after the end of the batch process. Therefore, even in the case of improper treatment, the aeration amount could not be controlled during the treatment.

Further, in order to effectively utilize BOD in human waste for treatment, it is necessary to suppress the amount of aeration at the initial stage of human discharge, but in the conventional DO control method, the amount of aeration during treatment is required. However, by controlling the aeration amount during the aeration period based on ORP as described above, it becomes possible to adjust the aeration amount and to effectively use BOD in human urine. It is possible to plan.

In the present invention, the setting and correction of the reference ORP pattern can be performed by the following procedure, for example. (1) Setting of the reference ORP pattern At a preset time, the aeration amount is set so that the DO reaches a predetermined value, and batch processing is performed. If the DO deviates from the predetermined value within the set time, the aeration is performed. The amount is multiplied by a coefficient to correct the aeration amount, and the next batch process is performed. The maximum value of the ORP in the batch process after the correction of the aeration amount is calculated as to how many times the maximum value of the ORP in the standard ORP change curve (standard ORP pattern) as shown in FIG. A reference ORP pattern is obtained by applying a correction to the ORP pattern. (2) ORP measured by the latest batch processing after continuing the calibration operation of the reference ORP pattern
ORP of 5 to 10 examples of change curve patterns
Of the standard ORP pattern is calculated, and the standard ORP pattern is corrected by multiplying the standard ORP pattern by the multiplication factor.

[0021] It is preferable that this correction is performed once a week.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of the biological denitrification apparatus of the present invention.

In FIG. 1, 1 is a biological treatment tank, 11 is a pipe for introducing raw water (pretreated and urine) having an input pump 11A, 2 is a storage tank 2A, methanol injection equipment is provided with a pipe 12 and a pump 12A, and 3 is a storage tank 3A. , A caustic soda injection facility equipped with a pipe 13 and a pump 13A, 4 is a storage tank 4A,
Defoaming agent injecting equipment equipped with piping 14 and pump 14A, 1
Reference numeral 5 is a discharge pipe for the treated water (treatment mixed liquid) equipped with a valve 15A. The defoaming agent injection pipe 14 has a branch pipe 16 provided with a spray pump 16A, and the branch pipe 16 is connected to the bottom of the biological treatment tank 1. Reference numeral 5 denotes an aeration equipment, which includes a pipe 17, an oxygen dissolution pump (circulation pump) 17A provided in the pipe 17, a cooler 6, an ejector 7, and a valve 18 connected to the ejector 7.
An air supply pipe 18 including A and an aeration pipe 19 are provided.

In the biological denitrification treatment apparatus of this embodiment, the biological treatment tank 1 is provided with the ORP meter 20,
This measured value is input to the arithmetic controller 8, and the arithmetic controller 8 uses the oxygen dissolution pump 1 based on the ORP measurement result.
A control signal for the rotation speed of 7 A is transmitted, and the aeration amount is adjusted by increasing or decreasing the circulating liquid amount.

In order to perform the batch-type biological denitrification treatment by such a biological denitrification treatment apparatus, for example, raw water (pretreated urine) is intermittently supplied from the pipe 11 through the pipe 11 at predetermined intervals. At the same time, the aeration is started by the aeration equipment 5 so that almost 100% nitrification and about 90% aerobic denitrification are simultaneously performed within a predetermined aeration time. next,
Aeration is stopped, methanol is injected from the methanol injection equipment 2, and a stirring process for a predetermined time is started, and about 10% of remaining nitric acid and nitrous acid are removed by a final denitrification treatment.

In the present embodiment, first, in the first batch process, the aeration amount is determined by multiplying the standard aeration amount by a coefficient (1 or less). The measured value of ORP during this aeration period is compared with a preset reference ORP pattern in the arithmetic and control unit 8 and the determination is performed according to the above (i) to (iii) to adjust the aeration amount. In addition, ORP immediately after stopping aeration and adding methanol
The pattern shape in the vicinity of the maximum value of the measured values is compared with the reference ORP pattern shape, the determination is performed according to the above-mentioned (1) to set the aeration amount in the next batch processing.

In the present invention, when the aeration amount is controlled during aeration, the control may be performed so that the reference ORP pattern is as close as possible. The amount of increase / decrease of the aeration amount may be uniform, but may be proportional (P control) to the difference from the reference ORP pattern, and of course, may be PID or the like.

When setting the aeration amount in the next batch processing, there is no particular limitation on the degree of increase / decrease of the aeration amount. In this case, a plurality of ORP patterns in the case of excessive aeration and insufficient aeration are set in advance, and the optimum setting value of the next aeration amount corresponding to them is obtained, and the optimum ORP pattern closest to the measured ORP pattern is set. It is advantageous to set a calculation formula in the arithmetic controller in advance so that the set value is the aeration amount for the next batch process.

In the biological denitrification treatment apparatus of the present invention, a DO meter is provided together with the ORP meter, and the ORP meter as described above is provided.
It is also possible to incorporate the conventional method of setting the aeration amount by DO into the control of the aeration amount based on the above.

The biological denitrification treatment apparatus shown in FIG. 1 is an embodiment of the biological denitrification treatment apparatus of the present invention. It is not limited. In the illustrated embodiment, the aeration amount is controlled by changing the rotation speed of the oxygen dissolution pump, that is, the amount of circulating water, but it can also be controlled by increasing or decreasing the amount of air blown in.

[0032]

As described above in detail, the biological denitrification treatment apparatus according to claim 1 and the biological denitrification according to claim 3 of the present invention.
According to the processing method , it is possible to reliably set the appropriate aeration amount for each batch process by controlling the aeration amount by the ORP with high reliability of the instrument.

The biological denitrification of claim 2 of the present invention
According to the treatment device and the biological denitrification treatment method according to claim 4.
For example, by properly controlling the aeration amount during the aeration period,
Good treatment can be performed by correcting the excess or deficiency of the aeration amount during the treatment.

According to the biological denitrification treatment apparatus and the biological denitrification treatment method of the present invention as described above, it is possible to prevent waste of electric power cost due to excessive aeration and increase in the amount of the defoaming agent, and to increase It is possible to stably and efficiently obtain treated water of water quality.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a biological denitrification treatment apparatus of the present invention.

FIG. 2 is a graph showing changes with time of DO, ORP and N concentrations in the biological treatment tank.

FIG. 3 is a graph showing changes with time of ORP and DO.

FIG. 4 is an enlarged view of a portion of FIG.

[Explanation of symbols]

1 biological treatment tank 2 Methanol injection equipment 3 Caustic soda injection equipment 4 Defoaming agent injection equipment 5 Aeration equipment 8 arithmetic controller 20 ORP meter

Continuation of the front page (56) Reference JP-A-61-54295 (JP, A) JP-A-62-42796 (JP, A) JP-A-62-227499 (JP, A) JP-A-62-286597 (JP , A) JP-A-5-309389 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 3/34 101 C02F 3/12

Claims (4)

(57) [Claims] 1. A treatment tank for receiving nitrogen-containing wastewater, Means for intermittently introducing nitrogen-containing wastewater into the treatment tank, Means for discharging treated water from the treatment tank to the outside of the tank; Aeration means for aerating the inside of the processing tank, For batch-type biological denitrification equipment for nitrification and denitrification
And A measuring means for measuring the ORP in the processing tank is provided, At the next batch processing based on the detected ORP value of the measuring means
The aeration amount control means to set the aeration amount ofBiological prolapse
A nitrogen treatment device, The aeration amount control means, Maximum ORP in the time-dependent curve of ORP in the treatment tank
Change the shape of the value near the value by changing the preset reference ORP
The shape near the maximum value of Compared to the standard ORP, it should have a gentle hill shape
For example, excessive aeration.   Sharper than that of the standard ORP
If the shape is acute, there is insufficient aeration.Standard ORP Toho
If the shape is almost the same, proper aeration is performed. Judge each
However, in the above case, the aeration amount in the next batch treatment
It is less than the aeration amount this time, and in the above case, the next
The aeration amount in the minute treatment is larger than the aeration amount this time.
In the above case, the aeration amount in the next batch treatment
Set the aeration amount for the next time so that it is about the same as this time.
It is a means to control the amount of aerationBiological characterized by
Denitrification treatment equipment. 2.A treatment tank for receiving nitrogen-containing wastewater, Means for intermittently introducing nitrogen-containing wastewater into the treatment tank, Means for discharging treated water from the treatment tank to the outside of the tank; An aeration means for aerating the inside of the processing tank, For batch-type biological denitrification equipment for nitrification and denitrification
And A measuring means for measuring the ORP in the processing tank is provided, Based on the detected ORP value of the measuring means,
Aeration that controls the amount of aeration Biological denitrification process for quantitative control
A device, The aeration amount control means, The rising curve of the time-dependent change of ORP in the processing tank is set in advance.
Compared with the rising curve of the standard ORP, (i) Soaring after that of the standard ORP and after that
If it follows a moderate rise, it is over-aeration. (ii) Those that rise linearly compared to those of the standard ORP
If so, there is insufficient aeration. (iii) If the rising curve is almost the same as the reference ORP, it is suitable.
Normal aeration. It is judged respectively, and in the case of (i) above,
In the case of (ii) above, increase the aeration amount so as to reduce the aeration amount.
In the case of (iii) above, the amount of aeration as it is
Exposure to control the amount of aeration during the batch process to maintain
Biological denitrification treatment characterized by being a volume control means
Processing equipment. 3.A treatment tank for receiving nitrogen-containing wastewater, Means for intermittently introducing nitrogen-containing wastewater into the treatment tank, Means for discharging treated water from the treatment tank to the outside of the tank; An aeration means for aerating the inside of the processing tank, Nitrogenation and denitrification using a batch-type biological denitrification equipment
Of biological denitrification treatment method for treating wastewater containing oxygen
hand, Measuring the ORP in the treatment tank, Set the aeration amount at the next batch processing based on the detected ORP value
A biological denitrification treatment method comprising: Maximum ORP in the time-dependent curve of ORP in the treatment tank
Change the shape of the value near the value by changing the preset reference ORP
The shape near the maximum value of Compared to the standard ORP, it should have a gentle hill shape
For example, excessive aeration. Sharper than that of the standard ORP
If the shape is acute, there is insufficient aeration. Standard ORP Toho
If the shape is almost the same, proper aeration is performed. Judge each
However, in the above case, the aeration amount in the next batch treatment
It is less than the aeration amount this time, and in the above case, the next
The aeration amount in the minute treatment is larger than the aeration amount this time.
In the above case, the aeration amount in the next batch treatment
Set the aeration amount for the next time so that it is about the same as this time.
A biological denitrification treatment method comprising: 4.A treatment tank for receiving nitrogen-containing wastewater, Means for intermittently introducing nitrogen-containing wastewater into the treatment tank, Means for discharging treated water from the treatment tank to the outside of the tank; An aeration means for aerating the inside of the processing tank, Nitrogenation and denitrification using a batch-type biological denitrification equipment
Of biological denitrification treatment method for treating wastewater containing oxygen
hand, Measuring the ORP in the treatment tank, Controls the amount of aeration during the batch processing based on the detected ORP value
A biological denitrification treatment method comprising: The rising curve of the time-dependent change of ORP in the processing tank is set in advance.
Compared with the rising curve of the standard ORP, (i) Soaring after that of the standard ORP and after that
If it follows a moderate rise, it is over-aeration. (ii) Those that rise linearly compared to those of the standard ORP
If so, there is insufficient aeration. (iii) If the rising curve is almost the same as the reference ORP, it is suitable.
Normal aeration. It is judged respectively, and in the case of (i) above,
In the case of (ii) above, increase the aeration amount so as to reduce the aeration amount.
In the case of (iii) above, the amount of aeration as it is
The aeration rate during the batch process can be controlled to maintain
And a biological denitrification treatment method.