Biological treatment apparatus and biological treatment method

Abstract

To provide a biological treatment apparatus and a biological treatment method using a treatment tank filled with carriers that can both prevent the carriers from floating by controlling the excessive growth of a biological film formed on the carriers and maintain and improve a contact efficiency between microorganisms (carriers) and treated water, thereby preventing a decline in treatment performance.SOLUTION: A biological treatment apparatus and a biological treatment method using this apparatus are provided. The apparatus is equipped with a treatment tank filled with carriers, an agitation part for agitating the carriers, a sedimentation detection section for detecting the sedimentation state of the carriers, and a control section for controlling the agitation intensity of the agitation part based on the detection results of the sedimentation detection section. According to the present invention, by controlling the agitation intensity according to the sedimentation state of the carriers, it is possible to control the occurrence of sedimentation itself in the treatment tank. This makes it possible to suppress the decline in treatment performance caused by the accumulation of carriers filled in the treatment tank.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a biological treatment apparatus and a biological treatment method. In particular, it relates to a biological treatment apparatus and a biological treatment method for performing biological treatment using a treatment tank filled with carriers.

Background Art

[0002] Generally, as a method for treating water to be treated containing organic matter, biological treatment using various microorganisms is known. In particular, biological treatment under an anaerobic environment (hereinafter referred to as "anaerobic treatment") has high merits in terms of introduction, such as not requiring aeration power and hardly generating excess sludge.

[0003] And, as one of the methods for further increasing the concentration of microorganisms in the treatment tank when performing biological treatment, it is also known to use a treatment tank filled with carriers. In particular, the fluidized bed type in which the carriers filled in the treatment tank are fluidized by a water flow or a stirring mechanism is widely used, and is also called the MBBR (Moving Bed Biofilm Reactor) method.

[0004] In the MBBR method, it is important to achieve sufficient contact between the biofilm formed on the carrier surface and the water to be treated, and it is necessary to maintain good fluidity of the carriers in the treatment tank. Also, in the MBBR method, when gas (biogas) is generated by biological treatment, the biogas may be enclosed inside the biofilm formed on the carrier, or the generated biogas may adhere to the carrier surface, etc., resulting in the carriers floating to the upper part (water surface) of the treatment tank.

[0005] Here, in the MBBR method, if the fluidity cannot be maintained well or the carriers float to the upper part of the treatment tank, the contact efficiency between the microorganisms and the water to be treated will drastically decrease, and the treatment efficiency will decrease. For example, Patent Document 1 describes that in biological treatment by the MBBR method, bubble-dissipating means is provided to dissipate bubbles by sandwiching the carrier floating in the tank between a rotating plate and a stationary plate, thereby preventing or suppressing the detachment of the biofilm formed on the carrier and suppressing the floating of the carrier.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] As described in Patent Document 1, in the MBBR method, it is known to suppress the floating of the carrier by dissipating (removing) the bubbles attached to the carrier floating in the tank due to the generation of biogas. On the other hand, although Patent Document 1 describes preventing or suppressing the detachment of the biofilm formed on the carrier, one of the factors causing the carrier to float in the MBBR method is considered to be that excessive growth of the biofilm occurs on the carrier surface, making it easier for biogas to be encapsulated inside the biofilm. That is, with the technology described in Patent Document 1, it is impossible to adjust the biofilm that has once grown excessively to a thickness that does not (is difficult to) encapsulate biogas, and even if the bubbles are dissipated from the carrier and it sinks, it will float again. Therefore, in biological treatment by the MBBR method, instead of dissipating (removing) bubbles from the floating carrier, it is required to create a situation where bubbles are not (are difficult to) be encapsulated in the carrier (inside the biofilm) in the first place.

[0008] An object of the present invention is to provide a biological treatment apparatus and a biological treatment method using a treatment tank filled with a carrier, which can prevent the carrier from floating by suppressing the excessive growth of the biofilm formed on the carrier, and can achieve both the maintenance and improvement of the contact efficiency between the microorganism (carrier) and the water to be treated, and suppress the degradation of the treatment performance.

Means for Solving the Problems

[0009] As a result of intensive studies on the above problems, the present inventor has found that in a biological treatment apparatus and a biological treatment method using a treatment tank filled with a carrier, due to insufficient stirring intensity and the deposition of the carrier in the treatment tank, in addition to the decrease in the contact efficiency between the microorganism and the water to be treated, the amount of detachment of the biofilm formed on the carrier decreases, and excessive growth of the biofilm occurs. Based on this finding, by suppressing the deposition of the carrier in the treatment tank, it is possible to achieve both the prevention of the carrier from floating and the maintenance and improvement of the contact efficiency between the microorganism and the water to be treated, and to suppress the degradation of the treatment performance, thus completing the present invention. That is, the present invention relates to the following biological treatment apparatus and biological treatment method.

[0010] The biological treatment apparatus of the present invention for solving the above problems is characterized by comprising a treatment tank filled with a carrier, a stirring unit for stirring the carrier, a deposition detection unit for detecting the deposition state of the carrier, and a control unit for controlling the stirring intensity of the stirring unit based on the detection result of the deposition detection unit. The biological treatment apparatus of the present invention is based on the finding that in a treatment tank filled with a carrier, the deposition of the carrier in the treatment tank leads to a decrease in the treatment performance. According to this feature, by controlling the stirring intensity according to the deposition state of the carrier, it is possible to suppress the continuation of the state where the carrier is deposited in the treatment tank, and further suppress the occurrence of deposition itself. Thereby, it is possible to achieve both the prevention of the carrier from floating in the treatment tank and the maintenance and improvement of the contact efficiency between the microorganism and the water to be treated, and to suppress the degradation of the treatment performance.

[0011] In addition, as one embodiment of the biological treatment apparatus of the present invention, the control unit controls to increase the stirring intensity by the stirring unit after the occurrence of carrier deposition in the treatment tank based on the detection result by the deposition detection unit, while decreasing the stirring intensity by the stirring unit after the elimination of carrier deposition in the treatment tank. According to this feature, in addition to attempting to eliminate carrier deposition by increasing the stirring intensity after the occurrence of carrier deposition, it is possible to suppress the excessive consumption of energy of the entire apparatus (particularly the energy related to driving the stirring unit) by decreasing the stirring intensity after the elimination of carrier deposition, and in combination with suppressing the decrease in treatment performance, it becomes possible to optimize the energy consumption related to the operation of the apparatus.

[0012] In addition, as one embodiment of the biological treatment apparatus of the present invention, the control unit has a feature of controlling the stirring intensity by the stirring unit using information related to the driving of the stirring unit. According to this feature, in controlling the stirring intensity by the stirring unit, by using information related to the driving of the stirring unit in addition to the deposition state of the carrier in the treatment tank, it becomes easy to improve the accuracy of control related to both suppressing and eliminating the occurrence of carrier deposition and optimizing the energy consumption related to the driving of the stirring unit. As a result, it becomes possible to further optimize the treatment in the biological treatment apparatus using a treatment tank filled with carriers.

[0013] In addition, as one embodiment of the biological treatment apparatus of the present invention, the deposition detection unit has a feature of being provided near the side wall of the treatment tank. According to this feature, since the deposition detection unit is provided at a location where carrier deposition is likely to occur in the treatment tank, it becomes possible to quickly and accurately grasp the presence or absence of deposition as the deposition state of the carrier in the treatment tank. As a result, the accuracy of control by the control unit can be improved, and it becomes possible to further suppress the decrease in treatment performance.

[0014] In addition, as one embodiment of the biological treatment apparatus of the present invention, the deposition detection unit has a feature of being able to acquire a plurality of detection results in the depth direction of the treatment tank. According to this feature, it becomes possible to quickly and accurately grasp the tendency leading to the occurrence of carrier deposition as the deposition state of the carrier in the treatment tank. Thereby, the accuracy of control by the control unit can be improved, and it becomes possible to further suppress the decrease in treatment performance.

[0015] The biological treatment method of the present invention for solving the above problems includes a biological treatment step using a treatment tank filled with a carrier, a stirring step for stirring the carrier, a deposition detection step for detecting the deposition state of the carrier, and a control step for controlling the stirring intensity of the stirring step based on the detection result of the deposition detection step. As described above, the biological treatment method of the present invention is based on the finding that in a treatment tank filled with a carrier, the deposition of the carrier in the treatment tank leads to a decrease in treatment performance. According to this feature, by controlling the stirring intensity according to the deposition state of the carrier, it is possible to suppress the state in which the carrier is deposited in the treatment tank. Thereby, it is possible to achieve both prevention of carrier floating in the treatment tank and maintenance / improvement of the contact efficiency between microorganisms and the water to be treated, and it is possible to suppress the decrease in treatment performance.

Effects of the Invention

[0016] According to the present invention, in a biological treatment apparatus and a biological treatment method using a treatment tank filled with a carrier, it is possible to provide a biological treatment apparatus and a biological treatment method that can achieve both prevention of carrier floating by suppressing excessive growth of the biofilm formed on the carrier and maintenance / improvement of the contact efficiency between microorganisms (carriers) and the water to be treated, and suppress the decrease in treatment performance.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments of the biological treatment apparatus and the biological treatment method according to the present invention will be described in detail with reference to the drawings. Regarding the biological treatment method in the present invention, it shall be replaced with the description of the operation of the biological treatment apparatus according to the present invention. Note that the biological treatment apparatus and the biological treatment method described in the embodiments are merely examples for explaining the biological treatment apparatus and the biological treatment method according to the present invention, and are not limited thereto.

[0019] The biological treatment apparatus and the biological treatment method of the present invention are used for treating treated water containing organic substances to be biologically treated, and are particularly preferably used in the biological treatment of wastewater containing organic substances.

[0020] Here, the wastewater containing organic substances that is particularly suitable as the treatment target of the present invention includes industrial wastewater discharged from various factories such as food factories, chemical factories, and paper pulp factories, and domestic wastewater such as sewage. Note that the wastewater containing organic substances is not limited thereto, and any wastewater containing organic substances that can be biologically treated under aerobic or anaerobic conditions can be the treatment target of the present invention. Examples of such wastewater include livestock manure and organic wastewater containing sludge (excess sludge).

[0021] In addition, the biological treatment in the present invention may be either aerobic treatment or anaerobic treatment, and is not particularly limited. In anaerobic treatment using a treatment tank filled with a carrier, compared with aerobic treatment, the carrier is likely to float due to the bio-gas generated in the biological treatment process being encapsulated in the biofilm. Therefore, the biological treatment apparatus and the biological treatment method of the present invention exhibit particularly high effects when applied to the anaerobic treatment of the water to be treated. At this time, as the microorganisms used in (involved in) the biological treatment in the present invention, any microorganisms capable of treating (decomposing) organic substances according to the type of biological treatment (aerobic treatment or anaerobic treatment) may be used. The specific types of microorganisms are not particularly limited, and known microorganisms widely used in aerobic treatment or anaerobic treatment can be used. Hereinafter, in the description of the embodiments, anaerobic treatment will be mainly described as the biological treatment, but it is not limited thereto.

[0022] [First Embodiment] FIG. 1 is a schematic explanatory view of the biological treatment apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the biological treatment apparatus 1A in the present embodiment includes a treatment tank 2 filled with a carrier P therein for introducing the water to be treated W0 and performing biological treatment, a stirring unit 3 for stirring the carrier P, a deposition detection unit 4 for detecting the deposition state of the carrier P in the treatment tank 2, and a control unit 5 for controlling the stirring intensity of the stirring unit 3 based on the detection result of the deposition detection unit 4. Further, it has a line L1 which is an introduction pipe for introducing the water to be treated W0 into the treatment tank 2, and a line L2 which is a discharge pipe for discharging the treated water W1 discharged from the treatment tank 2 to the outside of the system. Note that the dashed arrows in FIG. 1 indicate that they are connected so as to be inputtable / outputtable or controllable.

[0023] The treatment tank 2 is a reaction tank for biologically treating the water to be treated W0 (anaerobic treatment in this embodiment). As shown in FIG. 1, the water to be treated W0 is supplied to the treatment tank 2 through the line L1 provided in the treatment tank 2. In the treatment tank 2, the components contained in the water to be treated W0 are decomposed by the microorganisms present inside (anaerobic microorganisms in the case of anaerobic treatment). Then, the treated water W1 after biological treatment is discharged from the treatment tank 2 through the line L2 provided in the treatment tank 2. When performing anaerobic treatment, the treatment tank 2 is preferably a closed system to maintain an anaerobic environment. Hereinafter, the biological treatment in the treatment tank 2 of this embodiment will be referred to as "anaerobic treatment", and the microorganisms present in the treatment tank 2 will be referred to as "anaerobic microorganisms". However, as described above, it is not limited to this.

[0024] The line L1 for introducing the water to be treated W0 into the treatment tank 2 is not particularly limited regarding the connection location and structure to the treatment tank 2. However, as shown in FIG. 1, in addition to connecting a pipe to the lower part of the side wall of the treatment tank 2, it can be connected to a distributor (dispersion pipe, dispersion plate, etc.) provided at the bottom of the treatment tank 2 to introduce the water to be treated W0 into the treatment tank 2. This facilitates the control of the flow rate of the water to be treated W0 introduced into the treatment tank 2 and makes it easy to maintain the fluidity of the carrier in the treatment tank 2. Also, a pump may be provided in the line L1 (not shown) so that the water to be treated W0 forms a stable upward flow in the treatment tank 2.

[0025] When performing anaerobic treatment in the treatment tank 2 as in this embodiment, the microorganisms (anaerobic microorganisms) to be used may be any that can perform biological treatment under anaerobic conditions. For example, as anaerobic microorganisms, acid-forming bacteria and methane-forming bacteria that perform methane fermentation treatment can be used. Other anaerobic microorganisms include denitrifying bacteria used in denitrification treatment for reducing nitrate and nitrite, and sulfate-reducing bacteria used in sulfate reduction treatment for reducing sulfuric acid, etc. In particular, from the viewpoint of enabling effective utilization of the biogas generated during the anaerobic treatment process, it is preferable to use anaerobic microorganisms that perform methane fermentation treatment. Note that as the anaerobic microorganisms in this embodiment, isolated microorganisms may be used, or seed sludge from other wastewater treatment facilities or the like may be used. Further, anaerobic microorganisms contained in the water to be treated W0 may be utilized.

[0026] Note that the treatment tank 2 in this embodiment can be further provided with various additional facilities. For example, the treatment tank 2 may be provided with means for adjusting the internal water temperature, means for injecting a pH adjuster, and means for adding metals such as nitrogen, phosphorus, cobalt, and nickel, which are nutrient sources required by microorganisms. In particular, when performing methane fermentation by acid-forming bacteria and methane-forming bacteria as anaerobic treatment, it is preferable that the treatment tank 2 is provided with means for recovering, purifying, and storing methane gas as an additional facility.

[0027] And the treatment tank 2 in this embodiment is filled with the carrier P, and microorganisms (anaerobic microorganisms in this embodiment) involved in biological treatment adhere to the surface of this carrier P, and a biofilm is formed, whereby it becomes possible to retain anaerobic microorganisms in the treatment tank 2. Thereby, it becomes possible to increase the concentration of anaerobic microorganisms in the treatment tank 2 and improve the anaerobic treatment efficiency.

[0028] The carrier P in this embodiment is also called a microorganism carrier, and any solid material to which microorganisms involved in biological treatment adhere may be used, and there is no particular limitation on the material and shape. Specific examples of the material of the carrier P include, for example, silica sand, ceramics, activated carbon, polymers, clay, incineration ash, blast furnace granulated slag, and the like. At this time, from the viewpoint of excellent sedimentation properties and easy maintenance of fluidity in the treatment tank 2, it is preferable to use a carrier P having a specific gravity greater than that of the water to be treated W0. Specific examples of the shape of the carrier P include, for example, spherical, pellet-shaped, honeycomb-shaped, small cylindrical, tube-shaped, cubic-shaped, and the like. Note that, as the carrier P of the present embodiment, the presence or absence of pores is not particularly limited. However, from the viewpoint of being able to adsorb components that inhibit anaerobic treatment by anaerobic microorganisms in addition to retaining anaerobic microorganisms, it preferably has pores, and it is preferable to use a carrier (such as a porous carrier) having a structure with a high porosity.

[0029] The stirring unit 3 is for stirring the carrier P and the water to be treated W0 in the treatment tank 2 in order to ensure the fluidity of the carrier P and increase the contact efficiency between the carrier P and the water to be treated W0. As the stirring unit 3 in the present embodiment, it is only necessary that stirring in the treatment tank 2 is possible and the stirring intensity is variable, and the specific structure is not particularly limited. As a specific example of the stirring unit 3, for example, as shown in FIG. 1, it has a motor 31, a shaft 32, and stirring blades 33, and transmits the rotational force of the motor 31 installed above the treatment tank 2 to the stirring blades 33 via the shaft 32. At this time, by making the rotational force of the motor 31 (the rotational speed of the stirring blades 33) adjustable (controlled) by the control unit 5 described later, it becomes possible to change the stirring intensity.

[0030] Also, as another example of the stirring unit 3, it may be one that performs stirring by supplying a fluid (gas / liquid) into the treatment tank 2. For example, separately from the line L1, a pipe for supplying a stirring fluid is connected to the treatment tank 2, and by making it possible to adjust (control) the supply amount (supply flow rate) of the fluid, the stirring intensity can be made variable. More specifically, in the case of the stirring unit 3 that supplies a liquid for stirring, it is configured to adjust the discharge liquid amount to the treatment tank 2, and in the case of the stirring unit 3 that supplies a gas for stirring, by adjusting the aeration amount (aeration air volume or air diffusion amount) to the treatment tank 2, it becomes possible to change the stirring intensity. Note that when performing anaerobic treatment in the treatment tank 2 as in the present embodiment, in order to maintain the anaerobic environment in the treatment tank 2, as the stirring unit 3, it is preferable to perform stirring by the rotation of the stirring blades 33 as shown in FIG. 1.

[0031] By providing the stirring unit 3, the carrier P filled in the treatment tank 2 is stirred by the stirring unit 3 and flows in the treatment tank 2 to form a so-called fluidized bed. Then, the water to be treated W0 supplied into the treatment tank 2 via the line L1 undergoes anaerobic treatment by contacting the biofilm formed on the carrier P, and is discharged out of the system as the treated water W1 via the line L2.

[0032] Also, although the stirring unit 3 of the present embodiment has a variable stirring intensity, the types of parameters (hereinafter referred to as "stirring parameters") involved in the variation of the stirring intensity (control of the stirring intensity) are not particularly limited at this time. For example, as examples of the stirring parameters, in addition to the rotation speed of the stirring blades and the supply amount of the fluid (discharge liquid amount, aeration air volume, diffused air amount, etc.) as described above, the required power (input power) used for stirring, the mixing time, the stirring speed, the G value (also called the rapid stirring intensity, a value obtained from the stirring energy, the viscosity coefficient of water, and the tank volume), etc. can be mentioned. By controlling these stirring parameters, it becomes possible to control the stirring intensity.

[0033] The deposition detection unit 4 is for detecting the deposition state of the carrier P in the treatment tank 2. Here, the "deposition state" detected by the deposition detection unit 4 does not refer to the state related to the dispersion of the carrier P, but refers to the state related to the phenomenon (deposition) in which the carrier P that has settled in the treatment tank 2 stays and accumulates on the bottom of the treatment tank 2.

[0034] As shown in FIG. 1, the carrier P filled in the treatment tank 2 is stirred by the stirring unit 3, but does not always reach a uniform dispersion state. Some of the carrier P settles on the bottom side of the treatment tank 2, and there is a bias in the abundance ratio of the carrier P in the treatment tank 2. At this time, if the settled carrier P continues to stay on the bottom side of the treatment tank 2 without flowing, in addition to the decrease in the contact efficiency between the anaerobic microorganisms and the water to be treated W0, the amount of peeling of the biofilm formed on the carrier P decreases, and excessive growth of the biofilm occurs. And, as described above, due to the excessive growth of the biofilm, biogas is easily encapsulated inside the biofilm, causing the carrier P to float and leading to a decrease in treatment performance. Therefore, by detecting the deposition state of the carrier P rather than the dispersion state of the carrier P by the deposition detection unit 4, it becomes possible to obtain information regarding the measures (control of the agitation intensity by the control unit 5) necessary for suppressing the floating of the carrier P and maintaining and improving the contact efficiency between the microorganism (carrier P) and the water to be treated W0.

[0035] The deposition detection unit 4 in the present embodiment only needs to be able to detect the deposition state of the carrier P in the treatment tank 2, and the specific structure and device are not particularly limited. For example, as an example of the deposition detection unit 4 in the present embodiment, those that can acquire information regarding the behavior of the carrier P in the treatment tank 2 can be mentioned. More specifically, an image acquisition device such as a camera is used as the detection means 41 of the deposition detection unit 4 to observe and analyze the behavior of the carrier P from inside or outside the treatment tank 2. As another example, an optical sensor or a pressure sensor as the detection means 41 is provided in the treatment tank 2 to analyze the behavior of the carrier P. At this time, as the content of the behavior of the carrier P to be observed and analyzed, whether the carrier P stays within a certain region of the measurement range for a predetermined time or more, or whether the carrier P exists in a predetermined amount or more, etc. are used, and based on this, information regarding the deposition state of the carrier P can be acquired.

[0036] As another example of the deposition detection unit 4, information regarding the deposition state of the carrier P is acquired by acquiring information regarding the behavior of the fluid (mainly the water to be treated W0) in the treatment tank 2, rather than information regarding the direct behavior of the carrier P. More specifically, a flow meter such as an electromagnetic flow meter or an ultrasonic flow meter is used as the detection means 41 of the deposition detection unit 4 to obtain the flow velocity of the fluid in the treatment tank 2. At this time, when the flow velocity of the fluid is zero or close to zero, it can be determined that the carrier P also stays in the treatment tank 2, so that it becomes possible to acquire information regarding the deposition state of the carrier P.

[0037] The location where the deposition detection unit 4 is installed is not particularly limited as long as it can detect the deposition state of the carrier P. However, as shown in FIG. 1, it is particularly preferable to be near the side wall inside the treatment tank 2. Since the deposition detection unit 4 will be provided at a location where deposition of the carrier P is likely to occur inside the treatment tank 2, it becomes possible to quickly and accurately grasp the presence or absence of deposition of the carrier P inside the treatment tank 2. As a result, the accuracy of control by the control unit 5 described later can be improved, and it becomes possible to further suppress a decrease in treatment performance. In particular, when using a stirring blade 33 for the stirring unit 3 to rotate, since a stirring flow is generated from the center of the treatment tank 2 toward the side wall direction, deposition of the carrier P (increase in the abundance ratio of the carrier P and retention of the carrier P) is likely to occur on the side wall side of the treatment tank 2. Therefore, by providing the deposition detection unit 4 near the side wall inside the treatment tank 2, it will have a high effect.

[0038] Also, the deposition detection unit 4 may be configured to be able to obtain a plurality of detection results in the depth direction inside the treatment tank 2. FIG. 2 is a schematic explanatory diagram showing another aspect of the biological treatment apparatus 1A of the present embodiment. Regarding the same configuration as the biological treatment apparatus shown in FIG. 1, the same reference numerals are given and the description is omitted. As the biological treatment apparatus 1A in the present embodiment, as shown in FIG. 2, a plurality of detection means 41 (image acquisition devices, sensors, etc.) are provided inside the treatment tank 2 as the deposition detection unit 4, and analysis is performed based on the information obtained by each detection means 41, and it can be cited as obtaining a plurality of detection results in the depth direction inside the treatment tank 2. Also, as another example, a moving mechanism that can move up and down is provided for the detection means 41, and by moving the deposition detection unit 4 (detection means 41) up and down inside the treatment tank 2 to obtain information related to the deposition state, it can be cited as obtaining a plurality of detection results in the depth direction inside the treatment tank 2, etc. By the deposition detection unit 4 obtaining a plurality of detection results in the depth direction inside the treatment tank 2, it also becomes possible to quickly and accurately grasp information regarding the tendency leading to the occurrence of deposition of the carrier P among the deposition states of the carrier P inside the treatment tank 2. As a result, the accuracy of control by the control unit 5 described later can be improved, and it becomes possible to further suppress a decrease in treatment performance.

[0039] The control unit 5 is for controlling the agitation intensity of the agitation unit 3 based on the detection result of the deposition detection unit 4. As shown in FIGS. 1 and 2, the control unit 5 in the present embodiment may be any device that can acquire information related to the deposition state of the carrier P obtained by the deposition detection unit 4 and adjust the agitation intensity of the agitation unit 3 based on that information. There are no particular limitations on the specific means for acquiring and judging information from the deposition detection unit 4 or the specific means for adjusting the agitation intensity of the agitation unit 3. As the control unit 5, for example, it may include manual operations by an operator, but it is preferable to use a computing device that has a data input / output function for information acquisition and executes a program for performing calculations and transmitting control signals related to control by a processor such as a CPU, so as to enable automatic control. Thereby, it is possible to more reliably suppress the occurrence of deposition in the treatment tank 2 and effectively suppress the deterioration of the treatment performance.

[0040] Hereinafter, the control by the control unit 5 of the present embodiment will be described while showing specific examples. In this description, although the content of the control of the agitation intensity for the one that uses the rotation of the agitation blades 33 as the agitation unit 3 is shown, the control content of the control unit 5 is not limited to this, and it can be the control content of the agitation intensity according to the device / machinery constituting the agitation unit 3 or the type of agitation parameter.

[0041] FIG. 3 is a flowchart showing an example of the control content by the control unit 5 in the biological treatment apparatus 1A of the present embodiment. As shown in FIG. 3, first, as the initial operation (S1), an initial value of the agitation intensity (rotation speed of the agitation blades 33) of the agitation unit 3 is set, and the agitation unit 3 is operated so as to satisfy the set initial value (initial value of the rotation speed setting). Next, information acquisition related to the deposition state of the carrier P is performed by the deposition detection unit 4 (S2). When it is determined that the deposition of the carrier P has occurred (S3: YES), the stirring intensity of the stirring unit 3 is adjusted to increase, that is, the stirring unit 3 is operated so as to increase the rotation speed of the stirring blades 33 (S4). Then, the process returns to the step of detecting the deposition state by the deposition detection unit 4 again with the increased stirring intensity (S2), and the adjustment of the stirring intensity of the stirring unit 3 according to the presence or absence of deposition generation is repeated. On the other hand, when it is determined that the deposition of the carrier P has not occurred (S3: NO), the process returns to the step of detecting the deposition state by the deposition detection unit 4 again (S2), and the adjustment of the stirring intensity of the stirring unit 3 according to the presence or absence of deposition generation is repeated. Thereby, the generation of deposition of the carrier P in the treatment tank 2 can be suppressed, and the excessive growth of the biofilm formed on the carrier P can be suppressed, so that the reduction of the treatment performance can be suppressed. In addition, in the adjustment of the stirring intensity, it is not accompanied by a sudden (substantial) change in the stirring intensity. It is preferable to set a predetermined adjustment range and control to increase the stirring intensity step by step. Thereby, there is no sudden environmental change in the treatment tank 2, so the influence on the anaerobic treatment can be reduced, and excessive energy consumption (the driving energy consumption of the stirring unit 3) can be suppressed.

[0042] Here, regarding the adjustment range of the stirring intensity of the stirring unit 3 or the initial value of the stirring intensity, a value estimated from past treatment results may be used, or a value may be set from the calculation results at the time of designing the treatment tank 2 or the observation (monitoring) results of the actual treatment situation in the treatment tank 2.

[0043] Also, regarding the setting of various values (adjustment range and initial value) related to the stirring intensity, for example, the stirring speed at which complete suspension defined by Zwietering is achieved, that is, the just-suspended speed; N JS) may also be set based on this. Complete suspension means that all particles do not stay at the bottom of the tank for 1 to 2 seconds or more, and the complete suspension stirring speed can be obtained by the Zwietering correlation formula including parameters such as the device shape factor (the size of the tank, the type of stirring blades, etc.), particle diameter, and particle density. In addition, it can also be obtained using a new particle suspension limit stirring speed formula based on LDV flow velocity measurement or simulation. Further, without relying on arithmetic expressions, the complete suspension state in the treatment tank 2 or a test tank having a structural correlation with the treatment tank 2 can be observed visually, etc., and the complete suspension stirring speed can be obtained from the stirring speed (rotation speed of the stirring blades 33) at that time.

[0044] When the complete suspension stirring speed is obtained, it can first be used for setting the initial value of the stirring intensity. Then, as the anaerobic treatment in the treatment tank 2 progresses, changes in the properties of the carrier P (such as changes in the thickness of the biofilm formed on the carrier P) occur, so the value of the complete suspension stirring speed used for setting the initial value of the stirring intensity can no longer maintain the complete suspension state. Therefore, when the deposition detection unit 4 detects the occurrence of deposition, it is possible to recalculate the complete suspension stirring speed and set the value and adjustment range of the stirring intensity of the stirring unit 3 adjusted by the control unit 5. Thereby, the complete suspension state of the carrier P can always be maintained in the treatment tank 2, and it becomes easy to suppress the deposition of the carrier P.

[0045] FIG. 4 is a flowchart showing an example of another control content by the control unit 5 in the biological treatment apparatus 1A of the present embodiment. First, the initial operation (S1) and the step of acquiring information related to the deposition state of the carrier P by the deposition detection unit 4 (S2) are common to the control flow shown in FIG. 3.

[0046] Then, when it is determined that the deposition of the carrier P has occurred (S3: YES), the stirring intensity of the stirring unit 3 is adjusted to increase, that is, the stirring unit 3 is operated so as to increase the rotation speed of the stirring blades 33 (S4). On the other hand, when it is determined that the deposition of the carrier P has not occurred, that is, the deposition of the carrier P has been eliminated (S3: NO), the stirring intensity of the stirring unit 3 is adjusted to decrease, that is, the stirring unit 3 is operated so as to decrease the rotation speed of the stirring blades 33 (S5).

[0047] Furthermore, after the step (S4) of increasing the stirring intensity due to the occurrence of the deposition of the carrier P, the process returns to the step (S2) of detecting the deposition state by the deposition detection unit 4 again, and the adjustment of the stirring intensity of the stirring unit 3 according to the presence or absence of the deposition is repeated. On the other hand, after the step (S5) of decreasing the stirring intensity due to the elimination of the deposition of the carrier P, after a predetermined time has elapsed, the process returns to the step (S1) of operating the stirring unit 3 so as to satisfy the set initial value, and again passes through the step (S2) of detecting the deposition state by the deposition detection unit 4, and the adjustment of the stirring intensity of the stirring unit 3 according to the presence or absence of the deposition is repeated. Thereby, in addition to aiming to eliminate the deposition of the carrier P by increasing the stirring intensity after the deposition of the carrier P has occurred, by decreasing the stirring intensity after the deposition of the carrier P has been eliminated, the energy consumption of the entire biological treatment apparatus 1A (particularly the energy related to the drive of the stirring unit 3) is suppressed from becoming excessive, and in combination with suppressing the decrease in treatment performance, it becomes possible to optimize the energy consumption related to the operation of the apparatus.

[0048] In addition, as a result of determining the presence or absence of the carrier deposition by the deposition detection unit 4, when the carrier deposition has not occurred and the process of decreasing the stirring intensity (routine passing from S3: NO to S5) is repeated, it may be controlled to continuously decrease the stirring intensity, or it may be controlled to maintain the stirring intensity without decreasing it within a predetermined time. Thereby, the change in the stirring intensity (rotation speed of the stirring blades 33) is not repeatedly changed at a high frequency with respect to the stirring unit 3, and it becomes possible to reduce the load on the apparatus accompanying the change in the stirring intensity.

[0049] As described above, in the biological treatment apparatus 1A according to the present embodiment, by controlling the stirring intensity according to the deposition state of the carrier, it is possible to suppress the continuation of the state where the stirring intensity is insufficient and the carrier is deposited in the treatment tank, and further suppress the occurrence of deposition itself. As a result, it is possible to achieve both prevention of carrier floating in the treatment tank and maintenance / improvement of the contact efficiency between the microorganisms and the water to be treated, and it is possible to suppress a decrease in treatment performance.

[0050] [Second Embodiment] FIG. 5 is a schematic explanatory diagram of the biological treatment apparatus 1B according to the second embodiment of the present invention. As shown in FIG. 5, the biological treatment apparatus 1B according to the present embodiment is provided with a control unit 6 that controls the stirring intensity of the stirring unit 3 using information related to the drive of the stirring unit 3 in addition to the detection result by the deposition detection unit 4, instead of the control unit 5 in the biological treatment apparatus 1A in the first embodiment. Among the configurations of the biological treatment apparatus 1B according to the present embodiment, the description of the same configurations as those of the biological treatment apparatus 1A in the first embodiment will be omitted.

[0051] In the biological treatment apparatus 1B according to the present embodiment, in controlling the stirring intensity by the stirring unit 3, by using information related to the drive of the stirring unit 3 together with the detection result of the deposition state of the carrier in the treatment tank 2, it becomes easy to improve the accuracy of control related to both suppression / elimination of the occurrence of deposition of the carrier P and optimization of the energy consumption related to the drive of the stirring unit 3.

[0052] The control unit 6 according to the present embodiment only needs to be able to acquire information related to the drive of the stirring unit 3 together with the information related to the deposition state of the carrier P obtained by the deposition detection unit 4, and based on these information, adjust the stirring intensity of the stirring unit 3. There are no particular limitations on the specific means for acquiring and judging information from the stirring unit 3 and the deposition detection unit 4, and the specific means for adjusting the stirring intensity of the stirring unit 3. Incidentally, similar to the control unit 5 described above, the control unit 6 may also include manual operations by an operator. However, it is preferable to use a computing device that has a data input / output function for information acquisition and executes a program for performing calculations related to control and transmitting control signals by a processor such as a CPU, so that automatic control is possible. Thereby, it becomes possible to more reliably suppress the occurrence of deposits in the treatment tank 2 and effectively suppress the deterioration of the treatment performance.

[0053] Specific examples of the information related to the drive of the stirring unit 3 acquired by the control unit 6 include the drive time (continuous drive time) of the stirring unit 3 and the amount of energy consumption (electric power amount) related to the drive. Note that the information to be acquired may be an absolute value (or an instantaneous output value) in the drive of the stirring unit 3 or a cumulative value. By controlling the stirring intensity of the stirring unit 3 using such information, it is possible to advance the biological treatment while suppressing the occurrence of deposits of the carrier P without accompanying excessive energy consumption. That is, in addition to suppressing the deterioration of the treatment performance, it becomes possible to optimize the operation of the apparatus while suppressing an increase in the running cost.

[0054] Hereinafter, the control by the control unit 6 of the present embodiment will be described while showing specific examples. In this description, similar to the control content in the control unit 5, the control content related to the control of the stirring intensity for the one using the rotation by the stirring blades 33 as the stirring unit 3 is shown. However, the control content of the control unit 6 is not limited to this, and can be the control content of the stirring intensity according to the device / mechanism constituting the stirring unit 3 or the type of stirring parameter.

[0055] FIG. 6 is a flowchart showing an example of the control content by the control unit 6 in the biological treatment apparatus 1B of the present embodiment. As shown in FIG. 6, first, as an initial operation (S10), an initial value of the stirring intensity (rotation speed of the stirring blades 33) of the stirring unit 3 is set, and the stirring unit 3 is operated so as to satisfy the set initial value (initial value of the rotation speed setting). Note that the description of the initial value setting is the same as that in the control unit 5 described above, and thus the description is omitted. Next, the deposition detection unit 4 acquires information regarding the deposition state of the carrier P (S11).

[0056] Then, information on the energy consumption required for driving from the stirring unit 3 (the absolute value of the power consumption in this embodiment) is acquired and compared with a preset upper limit value of the energy consumption (power consumption upper limit value) (S12). At this time, when the information acquired from the stirring unit 3 is lower than the set upper limit value (S12: YES), the process proceeds to the step of determining the presence or absence of deposition of the carrier P (S13). On the other hand, when the information acquired from the stirring unit 3 exceeds the set upper limit value (S12: NO), the stirring intensity of the stirring unit 3 is adjusted to be lowered, that is, after proceeding to the step of operating the stirring unit 3 so as to lower the rotation speed of the stirring blades 33 (S14), the process returns to the step of detecting the deposition state by the deposition detection unit 4 (S11), and the adjustment of the stirring intensity of the stirring unit 3 according to the presence or absence of deposition is repeated.

[0057] Also, after proceeding to the step of determining the presence or absence of deposition of the carrier P (S13), when it is determined that the carrier P has been deposited (S13: YES), the stirring intensity of the stirring unit 3 is adjusted to be increased, that is, the stirring unit 3 is operated so as to increase the rotation speed of the stirring blades 33 (S15). Then, the process returns to the step of detecting the deposition state by the deposition detection unit 4 (S11) again with the stirring intensity increased, and the adjustment of the stirring intensity of the stirring unit 3 according to the presence or absence of deposition is repeated. On the other hand, when it is determined that the carrier P has not been deposited, that is, the deposition of the carrier P has been eliminated (S13: NO), the process returns to the step of detecting the deposition state by the deposition detection unit 4 (S11) while maintaining the stirring intensity of the stirring unit 3, and the adjustment of the stirring intensity of the stirring unit 3 according to the presence or absence of deposition is repeated.

[0058] In the control flow shown in FIG. 6, if the deposition of the carrier is eliminated below the preset upper limit value of the energy consumption, the stirring intensity will be maintained. Also, even if the stirring intensity is increased due to the non-elimination of the deposition of the carrier, when the set upper limit value of the energy consumption is exceeded, the stirring intensity of the stirring unit 3 is adjusted to be lowered. This makes it easy to suppress excessive energy consumption in adjusting the stirring intensity for suppressing the deposition of the carrier P in the treatment tank 2. That is, in addition to suppressing the reduction in treatment performance, it is possible to perform biological treatment with excellent running costs. In addition, in adjusting the stirring intensity, similar to the control unit 5, it is preferable to set a predetermined adjustment range and control to increase the stirring intensity step by step. Also, since the setting of the adjustment range at this time is the same as the description content in the above-described control unit 5, the description is omitted.

[0059] FIG. 7 is a flowchart showing an example of another control content by the control unit 6 in the biological treatment apparatus 1B of the present embodiment. First, the initial operation (S10) and the step (S11) of acquiring information related to the deposition state of the carrier P by the deposition detection unit 4 are common to the control flow shown in FIG. 6.

[0060] Then, instead of the step (S12) in the control flow shown in FIG. 6, information on the driving time (continuous driving time in the present embodiment) is acquired from the stirring unit 3 and compared with a preset upper limit value of the driving time (continuous driving time upper limit value) (S16). At this time, when the information acquired from the stirring unit 3 is lower than the set upper limit value (S16: YES), the process proceeds to the step (S13) of determining the presence or absence of deposition of the carrier P. On the other hand, when the information acquired from the stirring unit 3 exceeds the set upper limit value (S16: NO), the process proceeds to the step (S17) of adjusting to lower the stirring intensity of the stirring unit 3, that is, operating the stirring unit 3 so as to lower the rotation speed of the stirring blades 33. After that, the information (driving time) acquired from the stirring unit 3 is reset (S18), and the process returns to the step (S11) of detecting the deposition state by the deposition detection unit 4 again.

[0061] Furthermore, after proceeding to the step (S13) of determining the presence or absence of deposition of the carrier P, since the steps are the same as the control flow shown in FIG. 6, the description is omitted.

[0062] In the control flow shown in FIG. 7, if the deposition of the carrier is eliminated within the upper limit value of the preset driving time (continuous driving time), the stirring intensity will be maintained. Also, when the upper limit value of the set driving time is exceeded in the state where the deposition of the carrier has been eliminated, the stirring intensity of the stirring unit 3 is adjusted downward and the driving time is reset. Accordingly, in adjusting the stirring intensity for suppressing the occurrence of deposition of the carrier P in the treatment tank 2, the stirring intensity can be forcibly decreased according to the driving time, and it becomes easy to suppress excessive energy consumption. That is, in addition to suppressing a decrease in treatment performance, it becomes possible to perform biological treatment with excellent running costs.

[0063] As described above, in the biological treatment apparatus 1B according to the present embodiment, in addition to the deposition state of the carrier, by controlling the stirring intensity using information related to the driving of the stirring unit, it becomes easy to increase the accuracy of control related to both suppression / elimination of the occurrence of deposition of the carrier and optimization of the energy consumption related to the driving of the stirring unit. Thereby, it becomes possible to further optimize the treatment for the biological treatment apparatus using a treatment tank filled with a carrier.

[0064] Note that the above-described embodiment shows an example of a biological treatment apparatus and a biological treatment method. The biological treatment apparatus and the biological treatment method according to the present invention are not limited to the above-described embodiment, and the biological treatment apparatus and the biological treatment method according to the above-described embodiment may be modified without changing the gist described in the claims.

[0065] For example, the control content by the control unit 5 and the control unit 6 in the present embodiment may perform any one of them, or may combine a plurality of control contents. For example, by combining a plurality of control contents, it becomes easy to always maintain the stirring intensity for preventing the occurrence of deposition of the carrier P in the treatment tank 2, and it becomes easy to continue biological treatment in which the treatment environment including costs is optimized.

Industrial Applicability

[0066] The biological treatment apparatus and biological treatment method of the present invention are used for biological treatment of water to be treated using a treatment tank filled with carriers. In particular, the biological treatment apparatus and biological treatment method of the present invention are suitably used for anaerobic treatment accompanied by generation of biogas.

Explanation of reference numerals

[0067] 1A, 1B Biological treatment apparatus, 2 Treatment tank, 3 Stirring unit, 31 Motor, 32 Shaft, 33 Stirring blades, 4 Deposition detection unit, 41 Detection means, 5, 6 Control unit, L1, L2 Lines, P Carrier, W0 Water to be treated, W1 Treated water

Claims

1. A treatment tank filled with a carrier, A stirring unit for stirring the carrier, A deposition detection unit for detecting the deposition state of the carrier, A control unit for controlling the stirring intensity of the stirring unit based on the detection result by the deposition detection unit. A biological treatment apparatus characterized by comprising these components.

2. The control unit increases the stirring intensity by the stirring unit after the occurrence of deposition of the carrier in the treatment tank from the detection result by the deposition detection unit, while decreasing the stirring intensity by the stirring unit after the elimination of deposition of the carrier in the treatment tank. The biological treatment apparatus according to Claim 1, characterized in that it controls in such a manner.

3. The control unit uses information related to the drive of the stirring unit to control the stirring intensity by the stirring unit. The biological treatment apparatus according to Claim 1 or 2, characterized in that it does so.

4. The deposition detection unit is provided near the side wall of the treatment tank. The biological treatment apparatus according to Claim 1, characterized in that it is so provided.

5. The deposition detection unit is capable of acquiring a plurality of detection results in the depth direction within the treatment tank. The biological treatment apparatus according to Claim 1, characterized in that it is so capable.

6. A biological treatment process using a treatment tank filled with a carrier, A stirring process for stirring the carrier, A deposition detection process for detecting the deposition state of the carrier, A control process for controlling the stirring intensity of the stirring process based on the detection result of the deposition detection process. A biological treatment method characterized by comprising these components.

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