JP7407634B2 - Water treatment equipment and water treatment method - Google Patents

Description

The present invention relates to a water treatment device and a water treatment method. In particular, it is a water treatment device and a water treatment method related to nitrification and denitrification treatment of nitrogen components in water to be treated.

Various types of treatment means are known for wastewater treatment, and treatment means are selected depending on the components to be removed in the wastewater. For example, nitrification and denitrification treatment is one of the treatment methods when nitrogen components are included as a component to be removed in wastewater.

Such nitrification and denitrification treatment includes biological nitrification and denitrification treatment in which activated sludge is used to reduce nitrogen components in water to be treated to nitrogen gas. Biological nitrification and denitrification treatment using this activated sludge consists of a nitrification process in which ammonia nitrogen is nitrified to nitrate nitrogen and nitrite nitrogen by nitrifying bacteria under aerobic conditions, and a nitrification process in which ammonia nitrogen is nitrified to nitrate nitrogen and nitrite nitrogen under anaerobic conditions. It is known as a process consisting of a denitrification process in which nitrate nitrogen and nitrite nitrogen are reduced to nitrogen gas.

As part of this biological nitrification and denitrification treatment, air aeration and aeration stop are repeated alternately for the water to be treated containing nitrogen components, and the nitrification process under aerobic conditions and the denitrification process under anaerobic conditions are performed in one process. Intermittent aeration treatment, which is performed in cycles, is known.

For example, Patent Document 1 describes intermittent aeration treatment as a nitrification-denitrification treatment of water to be treated containing nitrogen components. In addition, Patent Document 1 discloses that the pH in a reaction tank that performs intermittent aeration treatment is measured over time, and if the difference between the maximum and minimum pH values in one cycle of intermittent aeration treatment is less than a predetermined value, , it is described that the amount of water to be treated to be supplied to the reaction tank is reduced.

Japanese Patent Application Publication No. 2008-36558

It is known that a water treatment device used for intermittent aeration treatment as described in Patent Document 1 can perform treatment in one tank, and the device can be easily miniaturized. For this reason, water treatment using intermittent aeration treatment is widely used to treat water containing nitrogen components.

In addition, water treatment using intermittent aeration involves performing air aeration and stopping aeration in one tank to proceed with the two-stage treatment process: nitrification under aerobic conditions and denitrification under anaerobic conditions. Therefore, operational management related to the treatment process is important. For this reason, it is necessary to grasp the processing status related to the progress of the nitrification process and denitrification process and perform control to maintain stable operation.

In Patent Document 1, pH is used as an index in order to understand the treatment state in intermittent aeration treatment. However, when pH is used as an index, since the treatment state of the water to be treated is indirectly evaluated, it cannot be said that the operation control in intermittent aeration treatment is fully optimized. Therefore, there is a need to optimize operational control in intermittent aeration treatment using an index that can more accurately evaluate the treatment state of water to be treated.

The purpose of the present invention is to directly grasp the nitrogen behavior in the water to be treated, accurately evaluate the treatment status of the water, and optimize the intermittent aeration operation in water treatment in which nitrogen components in the water to be treated are subjected to intermittent aeration. It is an object of the present invention to provide a water treatment device and a water treatment method that can perform the following steps.

As a result of intensive study on the above-mentioned problems, the present inventors have developed a water treatment equipment that performs intermittent aeration treatment that repeats stirring and aeration, and that the concentration of ammonia nitrogen and/or nitric acid Compare the initial value of the nitrogen concentration with the value after treatment, and adjust the operational distribution of stirring and aeration during the treatment time of the next cycle, and the amount of air supplied by aeration during the treatment time of the next cycle. The present invention was completed by discovering that by providing a control unit, it is possible to directly grasp the behavior of nitrogen in the water to be treated, accurately evaluate the treatment status of the water to be treated, and optimize the intermittent aeration operation.
That is, the present invention is the following water treatment device and water treatment method.

The water treatment device of the present invention for solving the above problems is a water treatment device that removes nitrogen components in water to be treated by intermittent aeration operation, and has one cycle of operation related to stirring and aeration. In the treatment time of one cycle, the initial value of ammonia nitrogen concentration and/or nitrate nitrogen concentration is compared with the value after treatment, and the operation allocation in the treatment time of the next one cycle and the treatment time of the next one cycle are determined. The present invention is characterized by comprising a control unit that adjusts the amount of air supplied by aeration.

According to the water treatment device of the present invention, the behavior of nitrogen in the water to be treated can be directly grasped by providing a control unit and comparing the initial value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration with the value after treatment. The treatment status of the water to be treated can be accurately evaluated. In addition, based on this comparison result, by adjusting the operation distribution of stirring and aeration in the treatment time of the next one cycle and the amount of air supplied by aeration in the treatment time of the next one cycle, it is possible to It is possible to perform detailed nitrogen control and optimize intermittent aeration operation.

Further, in an embodiment of the water treatment device of the present invention, the control unit controls the input amount of water to be treated based on the maximum value or minimum value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration during treatment. It has the characteristic of adjusting.
According to this feature, by using the maximum or minimum value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration during treatment in the control unit, the behavior of nitrogen in the water to be treated can be directly grasped. By accurately evaluating the water treatment status and adjusting the input amount of water to be treated based on this value, it is possible to finely control nitrogen in the water to be treated and optimize intermittent aeration operation. becomes possible.

Further, in an embodiment of the water treatment device of the present invention, the control unit controls the amount of hydrogen donor added based on the maximum or minimum value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration during treatment. It has the characteristic of adjusting.
According to this feature, by using the maximum or minimum value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration during treatment in the control unit, the behavior of nitrogen in the water to be treated can be directly grasped. By accurately evaluating the water treatment status and adjusting the amount of hydrogen donor added based on this value, it is possible to finely control nitrogen in the water being treated and optimize intermittent aeration operation. becomes possible.

The water treatment method of the present invention to solve the above problems is a water treatment method that removes nitrogen components in water to be treated by intermittent aeration operation, in which stirring and aeration operations are one cycle, and a predetermined In the treatment time of one cycle, the initial value of ammonia nitrogen concentration and/or nitrate nitrogen concentration is compared with the value after treatment, and the operation allocation in the treatment time of the next one cycle and the treatment time of the next one cycle are determined. It is characterized by a control process for adjusting the amount of air supplied by aeration.

According to the water treatment method of the present invention, as a control step, the behavior of nitrogen in the water to be treated can be directly understood by comparing the initial value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration with the value after treatment. The treatment status of treated water can be accurately evaluated. In addition, based on this comparison result, by adjusting the operation distribution of stirring and aeration in the treatment time of the next one cycle and the amount of air supplied by aeration in the treatment time of the next one cycle, it is possible to It is possible to perform detailed nitrogen control and optimize intermittent aeration operation.

According to the present invention, in water treatment in which nitrogen components in the water to be treated are subjected to intermittent aeration, the behavior of nitrogen in the water to be treated can be directly grasped, the treatment status of the water to be treated can be accurately evaluated, and the intermittent aeration operation can be optimized. It is possible to provide a water treatment device and a water treatment method that can perform the following steps.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing which shows the water treatment apparatus of the embodiment of this invention. It is a graph which shows an example of the measurement result by the measurement part in the water treatment apparatus of the embodiment of this invention. It is a flowchart which shows an example of control by the control part in the water treatment apparatus of the embodiment of this invention. It is a flowchart which shows another example of control by the control part in the water treatment apparatus of the embodiment of this invention. It is a flowchart which shows another example of control by the control part in the water treatment apparatus of the embodiment of this invention.

The water treatment device and water treatment method of the present invention are used to treat water to be treated containing nitrogen components. In particular, the water treatment device and water treatment method of the present invention are those in which the steps of stirring and aeration are performed once each on treated water containing nitrogen components as one of biological nitrification and denitrification treatments. This is used for intermittent aeration treatment in which one cycle of treatment is performed.

The water to be treated W in the present invention is not particularly limited as long as it contains a nitrogen component to be treated. Specific examples of such water to be treated include wastewater such as factory wastewater and domestic wastewater. In particular, examples of the water to be treated W containing ammonia nitrogen or nitrate nitrogen as a nitrogen component include sewage and human waste.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a water treatment device and a water treatment method according to the present invention will be described in detail with reference to the drawings. In addition, regarding the water treatment method of the present invention, the following description of the structure and operation of the water treatment device shall be substituted. Further, the structure of the water treatment device described in the embodiments is merely illustrated to explain the water treatment device according to the present invention, and the structure is not limited thereto.

[Embodiment]
(Water treatment equipment)
FIG. 1 is a schematic explanatory diagram of a water treatment device 10 in an embodiment of the present invention.
As shown in FIG. 1, the water treatment device 10 according to this embodiment includes a treatment tank 1 into which water to be treated W is input via a line L1, an aeration device 2, a stirring device 3, and a hydrogen donor addition 4, a measuring section 5 for measuring ammonia nitrogen concentration and/or nitrate nitrogen concentration, and a control section 6. Moreover, on the line L1, a to-be-treated water amount adjustment section 7 that adjusts the input amount of the to-be-treated water W is provided.
In addition, in FIG. 1, the dashed-dotted arrow indicates that the connection is possible for control or for input.

In the water treatment apparatus 10 of the present embodiment, intermittent aeration treatment is performed on the water to be treated W containing nitrogen components introduced into the treatment tank 1.
As shown in FIG. 1, a treatment tank 1 is provided with an aeration device 2 and a stirring device 3. Additionally, activated sludge containing microbial cells such as nitrifying bacteria and denitrifying bacteria is placed in the treatment tank 1 .
In this treatment tank 1, nitrogen components in the water to be treated W are treated by performing an intermittent aeration operation in which aeration by the aeration device 2 and stirring by the stirring device 3 are alternately repeated.
More specifically, by driving the aeration device 2 in the treatment tank 1, an aerobic (oxidizing) atmosphere is formed, and an oxidation reaction in which ammonia nitrogen is oxidized to nitrate nitrogen proceeds by nitrifying bacteria. . On the other hand, by driving the stirring device 3 within the processing tank 1, an anaerobic (reducing) atmosphere is formed, and a reduction reaction in which nitrate nitrogen is reduced to nitrogen gas by denitrifying bacteria progresses.
The treated water W1 treated in the treatment tank 1 is then discharged to the outside of the system via the line L2.

The aeration device 2 is for forming an aerobic atmosphere within the processing tank 1.
The aeration device 2 may be any device that can supply gas such as air or oxygen into the processing tank 1, and its specific structure is not particularly limited. An example of the aeration device 2 is one in which a gas diffuser 21 and a blower B are connected, as shown in FIG. 1, for example. Here, examples of the gas diffuser 21 include a gas diffuser having a plurality of nozzles, a tubular member made of a porous material, a tubular member provided with a large number of holes or slits, a gas diffuser made of a plate-like member, etc. It will be done. Further, the blower B may be any device as long as it is capable of pumping gas, such as a blower or a compressor. Thereby, gas can be supplied into the processing tank 1, the inside of the processing tank 1 will be under an aerobic atmosphere, and the nitrification process (oxidation reaction) by nitrifying bacteria can proceed.

The stirring device 3 is for forming an anaerobic atmosphere in the processing tank 1 by stirring the processing tank 1 when the aeration device 2 is stopped.
The stirring device 3 may be any device as long as it can stir the water to be treated W in the treatment tank 1, and its specific structure is not particularly limited. As shown in FIG. 1, the stirring device 3 includes, for example, one including a stirring blade 31, a stirring shaft 32 attached to the stirring blade 31, and a drive mechanism 33 for rotating the stirring blade 31. Thereby, the inside of the processing tank 1 can be stirred, the inside of the processing tank 1 can be brought into an anaerobic atmosphere, and the denitrification process (reduction reaction) using denitrifying bacteria can proceed.
Note that as the stirring device 3, a structure other than a stirring blade may be used. Further, stirring may be performed by a drive mechanism other than rotation.

The placement location of the stirring device 3 is not particularly limited. As shown in FIG. 1, in addition to providing stirring blades from the top side of the processing tank 1, stirring blades may be provided on the side wall side of the processing tank 1, or stirring blades may be provided on the bottom side of the processing tank 1. For example, it is necessary to provide a

The hydrogen donor addition unit 4 is for adding a hydrogen donor to the water W to be treated in the treatment tank 1 .
In the reduction reaction related to the denitrification step described above, hydrogen is required to advance the reaction. Normally, the BOD component in the water W to be treated functions as a hydrogen donor, but it may be insufficient depending on the quality of the water W to be treated and the treatment conditions. Therefore, by providing the hydrogen donor addition section 4 and adding a hydrogen donor to the water to be treated W as necessary, it is possible to efficiently advance the denitrification process.

The structure of the hydrogen donor addition section 4 is not particularly limited. For example, as shown in FIG. 1, there is a storage section 41 for storing a hydrogen donor, a pipe 42 for adding the hydrogen donor to the processing tank 1, and a pipe 42 for adjusting the amount of hydrogen donor added. An example is one having an adjustment mechanism 43 provided therein. Here, examples of the adjustment mechanism 43 include a flow rate adjustment valve and a pump.
Note that an easily decomposable organic substance may be used as the hydrogen donor. Examples of such organic substances include alcohol, organic acids such as acetic acid, and waste liquids containing sugar. In particular, as the hydrogen donor, it is preferable to use methanol, which also acts as a carbon source and an energy source for denitrifying bacteria. Furthermore, by using methanol as a hydrogen donor, it becomes easy to calculate the influence on the denitrification process (reduction reaction) depending on the amount added. This facilitates control of the amount of hydrogen donor added to the water W to be treated in the control unit 6, which will be described later.

The measurement unit 5 is for measuring the ammonia nitrogen concentration and/or the nitrate nitrogen concentration in the water W to be treated.
The measurement unit 5 may be any device that can measure at least either the ammonia nitrogen concentration or the nitrate nitrogen concentration, but it is more preferable that it can measure both the ammonia nitrogen concentration and the nitrate nitrogen concentration. . This improves the calculation accuracy regarding the optimization conditions for the intermittent aeration operation in the control unit 6, which will be described later.
The measurement unit 5 may be equipped with a known measuring device as an ammonia nitrogen concentration meter and a nitrate nitrogen concentration meter, respectively, to measure the ammonia nitrogen concentration and nitrate nitrogen concentration independently. Alternatively, the values of the ammonia nitrogen concentration and the nitrate nitrogen concentration may be obtained by combining either one of the nitrate nitrogen concentration meters and the total nitrogen concentration meter. Note that known measuring instruments capable of measuring the ammonia nitrogen concentration and/or the nitrate nitrogen concentration include those equipped with an ion electrode.
Further, it is preferable that the measurement unit 5 is capable of continuous measurement and automatic data transmission. This increases the calculation accuracy in the control section 6, which will be described later, and facilitates data input to the control section 6.

The treated water amount adjustment section 7 is for adjusting the amount of treated water W introduced into the treatment tank 1.
The amount of water to be treated may be adjusted by the amount adjusting section 7 as long as it can adjust the amount of water W to be treated that is introduced from the line L1 by the control section 6, which will be described later. As shown in FIG. 1, the treated water amount adjusting section 7 may be, for example, a flow rate regulating valve or a valve provided on the line L1, or may be controlled by an inverter of a treated water transfer device.

The control unit 6 is for controlling intermittent aeration operation in the treatment tank 1.
As shown in FIG. 1, the control unit 6 is controllably connected to the aeration device 2, stirring device 3, hydrogen donor addition unit 4, and water amount adjustment unit 7 to be controlled, and It is connected so that the measurement results of the measurement section 5 can be input.

The control unit 6 may be any unit as long as it is capable of controlling each component connected as a control target or acquiring information. As shown in FIG. 1, the control section 6 in this embodiment includes, for example, one including an information acquisition section 61, a calculation section 62, and an operation control section 63.

The information acquisition unit 61 acquires data related to the measurement results in the measurement unit 5.
The calculation unit 62 also calculates, based on the data acquired by the information acquisition unit 61, the driving time of the aeration device 2 related to the intermittent aeration operation, the driving time of the stirring device 3, and the amount of hydrogen donor added by the hydrogen donor addition unit 4. , the amount of water to be treated W to be inputted by the water amount adjustment unit 7, and other calculations related to the control of the intermittent aeration operation. Note that an explanation regarding this calculation will be given later.
Further, the operation control section 63 transmits a control signal based on the calculation result of the calculation section 2 to each component connected as a control target.

The information acquisition unit 61, the calculation unit 62, and the operation control unit 63 that constitute the control unit 6 may include manual operation by an operator, but have a data input/output function for information acquisition, It is preferable to enable automatic control using a computing device in which a processor such as a CPU executes a program for performing calculations related to control and issuing control signals. Thereby, it becomes easy to optimize the intermittent aeration operation of the water treatment device 10.

(Control of intermittent aeration operation in water treatment equipment)
Hereinafter, when performing intermittent aeration treatment of water to be treated containing nitrogen components as water to be treated W using the water treatment apparatus 10 of this embodiment, a suitable intermittent aeration operation according to the behavior of nitrogen in the water to be treated W will be described. Control will be explained using an example. Note that the explanations and flowcharts regarding each operation control are merely examples of embodiments, and are not limited thereto.

FIG. 2 is a graph schematically showing measurement results obtained by the measurement unit 5 within one cycle of processing time related to the intermittent aeration operation of the water treatment device 10 of this embodiment.
In the intermittent aeration operation of the present invention, the combination of stirring and aeration is defined as one cycle, and the order of stirring and aeration is not particularly limited. In this embodiment, for convenience of explanation regarding calculation processing, one cycle is shown as a cycle in which aeration is performed by the aeration device 2 after stirring by the stirring device 3, but the aeration device is not limited to this. One cycle may be one in which stirring is performed by the stirring device 3 after aeration by step 2.

FIG. 2 shows a state in which water to be treated W input into the water treatment device 10 is subjected to a denitrification step (reduction reaction) by driving the stirring device 3 and then to a nitrification step (oxidation reaction) by driving the aeration device 2. Fig. 2A shows changes over time in ammonia nitrogen concentration (Fig. 2A) and changes over time in nitrate nitrogen concentration (Fig. 2B).
At this time, the initial value of ammonia nitrogen concentration is C _NH4-N0 , the value after treatment is C _NH4-N1 , the maximum value during treatment is C _NH4-Nmax , and the initial value of nitrate nitrogen concentration is C _NO3-N0. , the value after processing is C _NO3-N1 , and the minimum value during processing is C _NO3-Nmin .
Further, at this time, the stirring time related to the denitrification step is T _D0 , the aeration time related to the nitrification step is T _N0 , and the treatment time of one cycle is T ₀ . Note that the relationship among T _DO , T _N0 , and T ₀ is such that T ₀ =T _D0 +T _N0 holds true. T ₀ is a predetermined treatment time for one cycle, and T _DO and T _N0 are reference times for stirring and aeration in treatment cycles after T ₀ .

When the data shown in FIG. 2 is input to the calculation unit 62 via the information acquisition unit 61, the calculation unit 62 calculates the initial value C _NH4-N0 of the ammonia nitrogen concentration and the post-processing value C _NH4-N1. Make a comparison. More specifically, the difference ΔC _NH4 (=C _NH4-N1 -C _NH4-N0 ) between the initial value C _NH4-N0 of the ammonia nitrogen concentration and the value after treatment C _NH4-N1 is calculated. The value of this difference ΔC _NH4 is compared with the set values X ₁ and X ₂ , and based on the value classification resulting from this comparison, the content related to the operation control in the next cycle is determined. Calculations related to this operation control will be described later.
Note that the set values X ₁ and X ₂ correspond to the variation in the ammonia nitrogen concentration or the measurement error of the ammonia nitrogen concentration that is allowed within one cycle, and the relationship of X ₁ > X ₂ holds. . In addition, normally, it is assumed that X ₁ and X ₂ have the same absolute value and have a positive/negative relationship, but this is not limiting, and it is assumed that X ₁ and X ₂ have different absolute values. Good too. The set values X ₁ and X ₂ can be determined as appropriate based on past processing results and the like.

Based on _the value division in the comparison of the value of the difference ΔC _NH4 and _the set values X _{1 and} Adjust the amount of air. Here, "operation allocation" is the time ratio of the denitrification process and the nitrification process within the treatment time of one cycle. In other words, it refers to the number of hours of stirring time and aeration time or the ratio of stirring time and aeration time. It is something.
Here, the processing time _T1 of the next cycle is assumed to be the same as the predetermined processing time _T0 of one cycle, and the processing time of one cycle itself is treated as a fixed value.
Further, the amount of air to be adjusted at this time is the amount of air necessary for nitrification, and can be determined based on the aeration time and the performance of the aeration device. For example, if the value of _the difference ΔC _NH4 is larger than the set value Control is performed to increase T _N1 . In addition, as the aeration time T _N1 increases, by determining the stirring time T _D1 in the next cycle from T ₁ -T _N1 , it is possible to adjust the operation allocation in the treatment time T ₁ in the next cycle.

Based on the calculation results of the calculation unit 62, the operation control unit executes operation allocation in the next cycle of processing time _T1 and adjustment of the amount of air supplied by aeration in the next cycle of processing time _T1 . 63 transmits control signals related to the driving time of the blower B of the aeration device 2 and the driving time of the drive mechanism 33 of the stirring device 3 to the respective components (the aeration device 2 and the stirring device 3).
As a result, it is possible to directly understand the behavior of nitrogen in the water to be treated W, accurately evaluate the treatment status of the water to be treated, and then finely control the nitrogen in the water to be treated, allowing for intermittent aeration operation. It becomes possible to optimize.

As mentioned above, the data used in the calculation unit 62 is not limited to only data based on the ammonia nitrogen concentration value, but data based on the nitrate nitrogen concentration value can be used as data, and similar calculation processing can be performed. The intermittent aeration operation may also be controlled. In addition, in calculating the operation allocation for the processing time T ₁ of the next cycle, in addition to calculating the stirring time T _D1 from the difference between the processing time T ₁ and the aeration time T _N1 , the processing time T ₁ and the stirring time T _D1 are The aeration time T _N1 may be determined by the difference between the aeration time T _N1 and the stirring time T _D1 .

In this embodiment, it is preferable to perform arithmetic processing using the values of the ammonia nitrogen concentration and the nitrate nitrogen concentration. Thereby, it becomes possible to optimize the intermittent aeration operation after understanding the behavior of nitrogen in the water W to be treated in more detail.

FIG. 3 shows a flowchart related to the control of the control unit 6 in the water treatment device 10 of this embodiment, in which both the ammonia nitrogen concentration and the nitrate nitrogen concentration are measured in the measurement unit 5, and the measured FIG. 6 is a flow diagram when the results are input to the information acquisition unit 61. FIG. Note that in the following explanation regarding control in the control unit 6, the processing time of one cycle is expressed as the processing time T (T=T ₁ =T ₀ ).

First, in the treatment time T of one cycle, the treatment is performed with stirring time T _D0 and aeration time T _N0 . Then, data on the ammonia nitrogen concentration and nitrate nitrogen concentration obtained by the measuring section 5 is input to the calculation section 62 via the information acquisition section 61. Here, the difference ΔC NH4 between the initial value C _NH4-N0 of the ammonia nitrogen concentration and the value after treatment C _{NH4-N1 is} calculated. The value of this difference ΔC _NH4 is compared with the set values X ₁ and X ₂ and the values are classified based on this comparison. As shown in FIG. 3, this value classification is divided into three, ΔC _NH4 <X ₂ , X ₂ ≦ΔC _NH4 ≦X ₁ , and X ₁ <ΔC _NH4 .

Next, _the difference ΔCNO3 between the initial value _CNO3-N0 of the nitrate nitrogen concentration and the value after treatment CNO3 _-N1 is calculated. The value of this difference ΔC _NO3 is compared with the set values Y ₁ and Y ₂ and the values are classified based on this comparison. As shown in FIG. 3, this value classification is divided into three: ΔC _NO3 <Y ₂ , Y ₂ ≦ΔC _NO3 ≦Y ₁ , and Y ₁ <ΔC _NO3 . Note that the set values Y ₁ and Y ₂ correspond to the allowable variation in nitrate nitrogen concentration or measurement error in nitrate nitrogen concentration within one cycle, and the relationship Y ₁ > Y ₂ holds. . In addition, normally Y ₁ and Y ₂ are assumed to have the same absolute value and have a positive/negative relationship, but this is not limiting, and Y ₁ and Y ₂ may be set to have different absolute values. Good too. The set values Y ₁ and Y ₂ can be appropriately determined based on past processing results, etc., similarly to the set values X ₁ and X ₂ .

The processing time for the next one cycle is determined based on the value divisions obtained by comparing the value of the difference ΔC _NH4 and the set values X ₁ and X ₂ , and the value divisions obtained by comparing the value of the difference ΔC _NO3 and the set values Y ₁ and Y ₂ . The aeration time T _N1 at T is adjusted to increase or decrease with respect to the aeration time T _N0 . This makes it possible to adjust the operation allocation during the processing time T of the next cycle and the amount of air supplied by aeration during the processing time T of the next cycle.

As shown in FIG. ₃ , if the value range related to the difference ΔC _NH4 is ΔC _{NH4 <} The aeration time T _N1 is adjusted to be shorter than the aeration time T _N0 . Furthermore, if the value category related to the difference ΔC _NH4 is X ₁ <ΔC _NH4 , no matter which range the value category of the difference ΔC _NO3 is, it is determined that the treatment in the nitrification process is not sufficient, and the aeration time T _N1 is Adjust the aeration time T to be greater than _N0 . On the other hand, if the value category for the difference ΔC _NH4 is X ₂ ≦ΔC _NH4 ≦X ₁ , and the value category for the difference ΔC _NO3 is ΔC _NO3 <Y ₂ , Y ₂ ≦ΔC _NO3 ≦Y ₁ , the aeration time T _N1 is The aeration time is kept the same as the time T _NO0 , that is, unchanged from the aeration time T _NO0 , but if the value category of the difference ΔC _NO3 is Y ₁ <ΔC _NO3 , it is necessary to carry out the denitrification process longer than the nitrification process. The aeration time T _N1 is adjusted to be shorter than the aeration time T _N0 .
In this way, by performing calculations using both the ammonia nitrogen concentration and the nitrate nitrogen concentration, the behavior of nitrogen in the water to be treated W can be more accurately understood and the treatment status of the water to be treated W can be evaluated. Therefore, nitrogen in the water to be treated W can be precisely controlled, and the intermittent aeration operation can be further optimized.

As mentioned above, in the explanation regarding the control based on FIG. 3, the measurement unit 5 uses the measured values of both the ammonia nitrogen concentration and the nitrate nitrogen concentration, but the invention is not limited to this. Not done. It is also possible to measure one of the concentrations and obtain an estimated value by calculation or the like for the unmeasured concentration. For example, when measuring ammonia nitrogen concentration, calculations may be performed to obtain an estimated value of nitrate nitrogen on the assumption that the entire amount of ammonia nitrogen is converted to nitrate nitrogen through aeration, and correction coefficients related to conversion may be performed. For example, calculations may be performed to obtain an estimated value by multiplying by .

The control by the control unit 6 in this embodiment uses the values of the ammonia nitrogen concentration and/or nitrate nitrogen concentration in the treatment, accurately grasps the nitrogen behavior, and evaluates the treatment state of the water to be treated W. It controls nitrogen in the water to be treated W, and in addition to the operational distribution of stirring and aeration within one cycle and the amount of air supplied by aeration, it also adjusts other factors related to intermittent aeration operation. is preferred.

In addition to the above-mentioned control contents, other controls by the control unit 6 in this embodiment include, for example, intermittent aeration based on the maximum or minimum value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration during treatment. This includes making adjustments to other factors related to driving.

FIG. 4 shows a flowchart relating to another control of the control unit 6 in the water treatment apparatus 10 of this embodiment.
The control shown in FIG. 4 is for adjusting the input amount of water W to be treated. In addition, the part surrounded by the broken line in FIG. 4 shows the common part with the flowchart shown in FIG.

First, in the treatment time T of one cycle, the treatment is performed with stirring time T _D0 and aeration time T _N0 . Then, as data on the ammonia nitrogen concentration and nitrate nitrogen concentration obtained by the measurement section 5, the maximum value CNH4 _-Nmax during processing of the ammonia nitrogen concentration is inputted to the calculation section 62 via the information acquisition section 61. do.
Next, the calculation unit 62 performs value classification by comparing the aeration time T _N0 with preset maximum aeration time T _Nmax and minimum aeration time T _Nmin . As shown in FIG. 4, this value classification is divided into three: T _N0 <T _Nmin , T _Nmin ≦T _N0 ≦T _Nmax , and T _Nmax <T _N0 .
Next, the maximum value C _NH4-Nmax of the ammonia nitrogen concentration during processing is compared with a preset upper limit value C _NH4-set , and the values are classified.

Value classification based on comparison of aeration time T _N1 with set maximum aeration time T _Nmax and minimum aeration time T _Nmin , maximum value C _NH4-Nmax during treatment of ammonia nitrogen concentration, and preset upper limit setting value C Based on the value classification obtained by comparison with _NH4-set , an adjustment is made to increase or decrease the input amount of water to be treated W in the treatment time T of the next cycle.

As shown in FIG. 4, C _{NH4 - Nmax} is _smaller than C _{NH4 - set} (C _{NH4 - Nmax} <C _NH4-set ), it is determined that there is surplus capacity in the nitrification process, and the amount of water to be treated W input during the treatment time T of the next cycle is adjusted to be increased. Furthermore, in any case of T _N0 <T _Nmin , T _Nmin ≦T _N0 ≦T _Nmax , and T _Nmax <T _N0 , C _NH4-Nmax is larger than C _NH4-set (C _NH4-set < C _NH4-Nmax ), it is determined that the treatment in the nitrification step has not caught up, and the amount of input water W to be treated in the treatment time T of the next cycle is adjusted to be reduced.

Here, when T _N0 < T _Nmin and T _Nmax < T _N0 , the setting value of T Nmin and the setting of T _Nmax at the processing time T of the next cycle are determined by the value classification of C _NH4-set and C _NH4 - _Nmax . Change the value. Thereby, it becomes possible to set the range of aeration time related to the nitrification process according to the actual situation of the nitrification process.
As shown in FIG. 4, when T _N0 <T _Nmin , if C _NH4-Nmax is smaller than C _NH4-set (C _NH4-Nmax < C _NH4-set ), the value of T _Nmin is adjusted to lower. do. On the other hand, when C _NH4-Nmax is larger than C _NH4-set (C _NH4-set <C _NH4-Nmax ), the value of T _Nmin is adjusted to be increased. Similarly, when T _Nmax <T _N0 , if C _NH4-Nmax is smaller than C _NH4-set (C _NH4-Nmax < C _NH4-set ), the value of T _Nmax is adjusted to be lower. On the other hand, when C _NH4-Nmax is larger than C _NH4-set (C _NH4-set <C _NH4-Nmax ), the value of T _Nmax is adjusted to be increased.

Based on the flowchart shown in FIG. 4, the operation control section 63 controls the drive (opening/closing) of the water amount adjustment section 7 in order to adjust the input amount of the water W to be treated during the treatment time T of the next cycle. The relevant control signal is transmitted. Thereby, the amount of water to be treated W introduced from the line L1 can be adjusted.
In this way, by performing calculations using the maximum value of the ammonia nitrogen concentration during treatment, the behavior of nitrogen in the water to be treated W can be more accurately understood and the treatment status of the water to be treated W can be evaluated. be able to. Furthermore, by adjusting the input amount of water to be treated based on this evaluation, nitrogen control in the water to be treated can be finely controlled, and intermittent aeration operation can be optimized.

FIG. 5 shows a flowchart related to another control of the control unit 6 in the water treatment apparatus 10 of this embodiment.
The control shown in FIG. 5 is for adjusting the amount of hydrogen donor added. In addition, the part surrounded by the broken line in FIG. 5 shows the common part with the flowchart shown in FIG.

First, in the treatment time T of one cycle, the treatment is performed with stirring time T _D0 and aeration time T _N0 . Then, as data on the ammonia nitrogen concentration and nitrate nitrogen concentration obtained by the measurement unit 5, the minimum value C _N03−Nmin during processing of the nitrate nitrogen concentration is input to the calculation unit 62 via the information acquisition unit 61. do. Here, when the value of C _NO3-Nmin becomes zero, it is determined that the treatment by the denitrification step is progressing in just the right amount, and the addition of the hydrogen donor during the treatment time of the next cycle is stopped.

On the other hand, if the value of C _NO3-Nmin is other than zero, it is determined that there is an excess or deficiency in the denitrification process, and the amount of hydrogen donor added is adjusted.
Here, the calculation unit 62 compares the minimum value C _NO3-Nmin during the treatment of nitrate nitrogen concentration with a preset lower limit set value C _NO3-set , and performs value classification.

The amount of hydrogen donor added during the treatment time T of the next cycle is determined based on the value classification based on the comparison between the minimum value _CNO3-Nmin during treatment of nitrate nitrogen concentration and the preset lower limit value _CNO3-set. Make adjustments to increase or decrease.

As shown in FIG. 5, when C _NO3-Nmin is larger than C _NO3-set (C _NO3-Nmin > C _NO3-set ), it is determined that the denitrification process is not sufficient, and the next cycle is The amount of hydrogen donor added during the treatment time T is adjusted to increase. In addition, when C _NO3-Nmin is smaller than C _NO3-set (C _NO3-set > C _NO3-Nmin ), it is determined that there is surplus capacity for the denitrification process, and the Adjust to reduce the amount of hydrogen donor added.

Based on the flowchart shown in FIG. 5, the operation control unit 63 controls the driving of the adjustment mechanism 43 in the hydrogen donor addition unit 4 in order to adjust the amount of hydrogen donor added during the processing time T of the next cycle. The relevant control signal is transmitted. Thereby, the amount of hydrogen donor added from the storage section 41 via the pipe 42 can be adjusted.
In this way, by performing calculations using the minimum value of the nitrate nitrogen concentration during treatment, the behavior of nitrogen in the water to be treated W can be more accurately understood and the treatment status of the water to be treated W can be evaluated. be able to. Furthermore, by adjusting the amount of hydrogen donor added based on this evaluation, nitrogen in the water to be treated can be finely controlled, and intermittent aeration operation can be optimized.

In addition, as mentioned above, in the explanation regarding the control based on FIGS. 4 and 5, the explanation is given using the maximum value during treatment of ammonia nitrogen concentration or the minimum value during treatment of nitrate nitrogen concentration. However, it is not limited to this. The data used in each control can be selected depending on the order of stirring and aeration within one cycle, the relationship between ammonia nitrogen concentration and nitrate nitrogen concentration (conversion by treatment), etc.
For example, the input amount of the water to be treated W may be adjusted based on the minimum value of the ammonia nitrogen concentration during treatment, and the input amount of the water to be treated W may be adjusted based on the maximum or minimum value of the nitrate nitrogen concentration during treatment. The amount of input may be adjusted. Further, the input amount of the water to be treated W may be adjusted by performing calculations that take into account data regarding both the ammonia nitrogen concentration and the nitrate nitrogen concentration.
Similarly, the amount of hydrogen donor added may be adjusted based on the maximum value of nitrate nitrogen concentration during treatment, and the amount of hydrogen donor added may be adjusted based on the maximum value or minimum value of ammonia nitrogen concentration during treatment. The amount added to the body may be adjusted. Alternatively, the amount of hydrogen donor added may be adjusted by performing calculations that take into account data regarding both the ammonia nitrogen concentration and the nitrate nitrogen concentration.

As described above, the water treatment device 10 of the present embodiment includes a control unit and compares the initial value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration with the value after treatment, thereby controlling nitrogen in the water to be treated. It is possible to directly understand the behavior and accurately evaluate the treatment status of the water to be treated. In addition, based on this comparison result, by adjusting the operation distribution of stirring and aeration in the treatment time of the next one cycle and the amount of air supplied by aeration in the treatment time of the next one cycle, it is possible to It is possible to perform detailed nitrogen control and optimize intermittent aeration operation.

In addition, the water treatment device 10 of this embodiment uses the maximum value or minimum value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration during treatment in the control unit to control nitrogen behavior in the water to be treated. By directly understanding and accurately evaluating the treatment status of the water to be treated, and based on this value, adjusting the input amount of the water to be treated and the amount of hydrogen donor added, it is possible to finely control nitrogen in the water to be treated. This makes it possible to optimize intermittent aeration operation.

In addition, the embodiment mentioned above shows an example of a water treatment apparatus and a water treatment method. The water treatment device and water treatment method according to the present invention are not limited to the embodiments described above, and the water treatment device and water treatment method according to the embodiments described above may be modified without changing the gist. .

The water treatment device of this embodiment may be one that performs intermittent aeration operation that repeats stirring and aeration, and is not limited to one that performs treatment in one tank (single tank). For example, intermittent aeration operation based on the control in this embodiment may be performed for a plurality of tanks. Thereby, the amount of water to be treated that can be treated within a predetermined period of time can be increased, making it possible to improve treatment efficiency.

The water treatment device and water treatment method of the present invention are suitably used for treatment of water to be treated containing nitrogen components. In particular, it is suitably used in nitrification and denitrification treatment in which nitrogen components in water to be treated are removed by intermittent aeration operation.

10 water treatment device, 1 treatment tank, 2 aeration device, 21 gas diffuser, 3 stirring device, 31 stirring blade, 32 stirring shaft, 33 drive mechanism, 4 hydrogen donor addition section, 41 storage section, 42 piping, 43 adjustment mechanism , 5 measurement unit, 6 control unit, 61 information acquisition unit, 62 calculation unit, 63 operation control unit, 7 treated water amount adjustment unit, B blower, L1 to L3 line, W treated water, W1 treated water

Claims (4)

A water treatment device that removes nitrogen components in water to be treated by intermittent aeration operation,
The operation related to stirring and aeration is considered to be one cycle, and the initial value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration is compared with the value after treatment at the predetermined treatment time of one cycle, and the values for the next one cycle are compared. 1. A water treatment device, comprising a control unit that adjusts the operation allocation during the treatment time and the amount of air supplied by aeration during the treatment time of the next cycle. 2. The control unit adjusts the input amount of the water to be treated based on a maximum value or a minimum value of ammonia nitrogen concentration and/or nitrate nitrogen concentration during treatment. water treatment equipment. Claim 1 or 2, wherein the control unit adjusts the amount of hydrogen donor added based on a maximum value or a minimum value of ammonia nitrogen concentration and/or nitrate nitrogen concentration during treatment. Water treatment equipment described in. A water treatment method for removing nitrogen components in water to be treated by intermittent aeration operation,
The operation related to stirring and aeration is considered to be one cycle, and the initial value of the ammonia nitrogen concentration and/or nitrate nitrogen concentration is compared with the value after treatment at the predetermined treatment time of one cycle, and the values for the next one cycle are compared. A water treatment method characterized by comprising a control step of adjusting operation allocation during treatment time and the amount of air supplied by aeration during the treatment time of the next cycle.