JP2015229150A - Anaerobic treatment apparatus, anaerobic treatment method, and display device of anaerobic treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anaerobic treatment apparatus capable of efficiently anaerobically treating low-concentration and low-temperature organic waste water.SOLUTION: The apparatus anaerobically treating organic waste water flowing into a vessel 1 using granule sludge in the vessel 1 is provided in which information regarding the flow rate in the vessel 1 is acquired by flow rate information acquisition means 11, and information regarding the concentration in the vessel 1 is acquired by concentration information acquisition means 12. A concentration curve based on the information regarding the flow rate and the information regarding the concentration are compared by comparison means 13, and an inflow rate into the vessel 1 is controlled by control means 14 based on the comparison result. Thus, organic matter concentration in the vessel 1 is changed, the organic matter concentration in the vessel 1 is controlled so as to be closer to a concentration curve at which low-concentration and low-temperature organic waste water can be optimally anaerobically treated, so that the low-concentration and low-temperature organic waste water is efficiently anaerobically treated.

Description

  The present invention relates to an anaerobic processing device, an anaerobic processing method, and a display device for an anaerobic processing device.

  Conventionally, the following is known in anaerobic treatment of organic wastewater containing organic components. When the temperature of organic wastewater is low (for example, 10-20 ° C), the growth rate of microorganisms that produce methane (granular sludge) and the substrate decomposition rate decrease, so the treatment performance of organic wastewater decreases. . In addition, when the organic matter concentration in the organic wastewater is low (for example, 0.15-1 g / L), the microorganisms that produce methane cannot secure the organic matter necessary for anaerobic treatment, so the performance of organic wastewater is low. descend.

  In the anaerobic treatment method described in Patent Document 1 below, as a method for anaerobically treating low temperature or low concentration organic wastewater, a one-pass mode and a circulation mode are repeatedly performed. In the one-pass mode, the organic waste water is anaerobically treated by the granular sludge in the container without being circulated. On the other hand, in the circulation mode, the organic waste water is circulated and anaerobically treated with the granule sludge. By repeating such a plurality of modes (forms), the inside of the container is physically and repeatedly agitated. In this anaerobic treatment method, low-concentration organic wastewater can be distributed and supplied from a plurality of different locations in the height direction of the reaction tank in both the one-pass mode and the circulation mode. Further, in the circulation mode, the anaerobic treated water taken out from the upper part of the reaction tank can be returned to a plurality of places having different height directions of the reaction tank. Therefore, in any mode of the one-pass mode and the circulation mode, the organic substance concentration is suppressed from decreasing toward the upper side of the reaction tank. For this reason, the substrate concentration in the reaction tank can be maintained above the substrate saturation constant of the methanogenic bacteria, and the organic matter resolution of retained sludge such as methanogenic bacteria in the entire reaction tank can be improved.

Japanese Patent No. 4982789

  As described above, intensive research has been conducted on the efficient anaerobic treatment of low-concentration, low-temperature organic wastewater, and further research is underway.

  Therefore, the present invention provides an anaerobic treatment apparatus, an anaerobic treatment method, and a display device provided in the anaerobic treatment apparatus capable of efficiently anaerobically treating low-concentration, low-temperature organic wastewater. With the goal.

  The inventors of the present invention have made extensive studies focusing on the organic matter concentration in the organic wastewater, regarding the configuration capable of anaerobically treating the low concentration and low temperature organic wastewater. As a result, it has been found that if the organic matter concentration is optimum for anaerobic treatment, the organic wastewater can be anaerobically treated even if the organic wastewater has a low concentration and a low temperature.

  The anaerobic treatment apparatus according to the present invention is an apparatus that anaerobically treats organic wastewater flowing into a container using granule sludge in the container, and obtains information related to the flow rate in the container. An acquisition means, a concentration information acquisition means for acquiring information related to the concentration in the container, a comparison means for comparing a concentration curve based on information related to the flow velocity and information related to the concentration, and a comparison result by the comparison means And a control means for controlling the flow rate of flow into the container based on the above.

  The anaerobic treatment method according to the present invention is a method for anaerobic treatment of organic wastewater flowing into a container using granular sludge in the container, and acquires information related to the flow rate in the container. A flow rate information acquisition step, a concentration information acquisition step for acquiring information related to the concentration in the container, a comparison step for comparing a concentration curve based on the information related to the flow rate and information related to the concentration, and the comparison step And a control step for controlling the flow rate of flow into the container based on the comparison result obtained by the above.

  According to such an anaerobic processing apparatus and anaerobic processing method, information related to the flow rate in the container and information related to the concentration in the container are acquired, and the concentration curve and concentration based on the information related to the flow rate are acquired. Is compared with information related to. Since the inflow flow rate into the container is controlled based on the comparison result, the concentration in the container can be changed, and the concentration in the container can be controlled to be close to the concentration curve. Therefore, by making the above-mentioned concentration curve an optimum concentration curve for anaerobic treatment of low concentration and low temperature organic wastewater, low concentration and low temperature organic wastewater can be efficiently anaerobically treated.

  Here, if a flow rate adjusting means for adjusting the flow rate is provided in the line, a line that circulates and returns a part of the treated water that has been anaerobically treated in the vessel is circulated. Can do. For this reason, the activity and growth of the microorganisms that produce methane in the container can be controlled, and the organic substance concentration in the container can be controlled to an optimum value.

  Further, the display device of the anaerobic treatment device according to the present invention is a display device of an anaerobic treatment device for anaerobically treating organic wastewater flowing into the container using granular sludge in the container. A comparison result of comparing a concentration curve based on information related to the flow rate of the gas and information related to the concentration in the container is displayed.

  According to such a display device, a comparison result obtained by comparing a concentration curve based on information related to the flow velocity in the container and information related to the concentration in the container is displayed. For this reason, by making the said density | concentration curve into a density | concentration curve optimal for the anaerobic process of the low concentration and low temperature organic waste_water | drain, the information of the gap between this optimal density | concentration curve and the density | concentration in a container can be displayed. Furthermore, this information can be grasped quickly by the operator and the operator.

  Thus, according to the present invention, an anaerobic treatment apparatus, an anaerobic treatment method, and a display device included in the anaerobic treatment apparatus that can efficiently anaerobically process low-concentration, low-temperature organic wastewater. Can be provided.

It is a schematic structure figure showing an anaerobic processing device concerning an embodiment of the present invention. It is a flowchart which shows the process sequence in the control apparatus in FIG. It is a figure which shows the density | concentration curve which concerns on embodiment of this invention. It is a figure which shows the other density | concentration curve which concerns on embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram showing an anaerobic processing apparatus according to an embodiment of the present invention, and FIG. 2 is a flowchart showing a processing procedure in the control apparatus in FIG.

  As shown in FIG. 1, an anaerobic treatment apparatus 100 is an anaerobic treatment of organic waste water, and includes a tank 1 (container) that is an anaerobic treatment tank as a main component. An acid generation tank 2 is provided.

  The tank 1 is EGSB (Expanded Granular Sludge Bed) treatment in which the granulation of the granule sludge bed G is promoted and expanded to improve the contact efficiency with the liquid to be treated containing organic components. Device.

  The acid generation tank 2 is provided in the middle of the line L1 for introducing organic wastewater into the tank 1, and organically oxidizes the organic wastewater so as to be a treatment liquid suitable for methane fermentation. The line L <b> 1 has a pump 3 (flow rate adjusting means) for pumping the liquid to be treated in the acid generation tank 2 to the tank 1 at a position downstream from the acid generation tank 2.

  The tank 1 performs anaerobic treatment by introducing organic wastewater, which is a liquid to be treated, from the line L1 through the introduction pipe 4 from the lower part of the tank 1, and here, the shape in which the upper and lower ends of the cylinder are closed. A granular sludge bed G is formed in the lower part of the tank 1. In the granular sludge bed G, granular anaerobic sludge in which microbes that produce methane self-aggregate and become fine particles accumulates.

  Above the granular sludge bed G in the tank 1, three for separating the biogas containing methane generated by the anaerobic treatment (methane fermentation process) in the tank 1, the granular sludge, and the treated water, respectively. A phase separation unit 6 is provided.

  Connected to the upper part of the tank 1 is a line L2 for discharging the treated water separated by the three-phase separator 6 to the subsequent stage, and for circulating a part of the treated water and returning it to the acid generation tank 2. Line L3 is connected. The line L3 is connected upstream of the acid generation tank 2 or the acid generation tank 2. The line L3 has a pump 8 (flow rate adjusting means) that pumps the treated water downstream.

  Here, in the present embodiment, a concentration sensor 9 that detects the organic matter concentration in the organic waste water is disposed in the line L1. Note that the concentration sensor 9 may be provided in an introduction pipe 4 described later in the tank 1. Even in this case, the organic substance concentration in the organic waste water flowing into the tank 1 can be detected. A concentration sensor 5 for detecting the concentration of organic matter in the organic waste water is disposed in the tank 1. A plurality of concentration sensors 5 are installed along the vertical direction in the tank 1. The density sensors 5 may be installed at equal intervals in the vertical direction. By comprising in this way, the organic substance density | concentration of the organic waste water in the tank 1 can be detected at equal intervals in the up-down direction.

  The three-phase separation unit 6 is provided with a flow rate sensor 7 that detects the flow rate of the organic waste water in the tank 1. The flow rate sensor 7 is disposed below a setter 6a for separating a solid from gas and liquid. The flow velocity sensor 7 may measure, for example, the linear velocity of the organic waste water flowing through the introduction pipe 4. In this case, the linear velocity of the organic waste water flowing in the introduction pipe 4 can be acquired as information related to the flow velocity in the tank 1.

  In particular, the anaerobic treatment apparatus 100 of the present embodiment includes a control device 10 that calculates a concentration curve in the container based on outputs from the concentration sensor 9 and the flow rate sensor 7. The control device 10 controls the driving of the pump 3 or the pump 8 so that the actually measured value by the concentration sensor 5 approaches the concentration curve.

  The control device 10 includes a flow rate information acquisition unit 11, a concentration information acquisition unit 12, a comparison unit 13, and a control unit 14. Further, the control device 10 includes a RAM that stores output information from the concentration sensors 5 and 9 and the flow velocity sensor 7 and a ROM that stores a processing procedure of the control means 14 in the form of a program.

  The flow rate information acquisition unit 11 acquires flow rate information in the tank 1 by the flow rate sensor 7. The flow rate information is the flow rate of the organic waste water in the vicinity of the settler 6a. The flow velocity information is not limited to this, and may be information measured at other positions in the tank 1. The flow velocity information acquired by the flow velocity sensor 7 is used for calculating a concentration curve described later.

  The density information acquisition unit 12 acquires density information from the density sensor 9. The density information acquired by the density sensor 9 is used for calculating a density curve described later. Further, the concentration information acquisition means 12 acquires concentration information in the tank 1 by the concentration sensor 5. The concentration information is the organic matter concentration of the organic waste water at a plurality of positions in the upper and lower positions in the tank 1.

  The comparing means 13 compares the concentration curve based on the flow rate information with the concentration information. The concentration curve based on the flow rate information will be described later.

  Based on the comparison result by the comparison means 13, the control means 14 controls the driving of the pump 3 so that the concentration measured by the concentration sensor 5 approaches the concentration given by the concentration curve. Control the flow rate. Alternatively, the control means 14 controls the amount of treated water to be circulated by controlling the driving of the pump 8 so that the concentration measured by the concentration sensor 5 approaches the concentration given by the concentration curve. To control the inflow flow rate.

Here, the density curve will be described. In the anaerobic treatment, microorganisms (anaerobic bacteria or the like) that generate methane in the granular sludge decompose organic substances in the tank 1, whereby the organic substance concentration in the organic waste water changes. The inventors have found that when anaerobic treatment is performed on wastewater having a low organic substance concentration, there is an optimum organic substance concentration for the microorganisms to efficiently decompose the organic substance. At this time, the mass balance formula in the tank 1 can be expressed by the following formula (1).

Here, the diffusion coefficient D, the reaction order n, the flow velocity u, the organic matter concentration C _A in the organic waste water flowing into the tank 1, and the reaction rate constant κ are values measured by experiments or values corresponding to the experimental values. be able to. The variable l is an amount corresponding to the depth direction of the tank 1. In equation (1), variable conversion is performed so that the variable 1 corresponding to the depth of the tank 1 is dimensionlessly quantified, and when the reaction in the mass balance equation is a primary reaction, the following equation (2) is obtained. A concentration dependent equation is obtained.

Here, as the organic substance concentration X _A in the tank 1, the organic substance concentration C _A0 in the organic waste water flowing into the tank, and the residence time τ, values measured by experiments are used. The variable z is an amount corresponding to the depth direction of the tank 1, and the column length L is appropriately set when the above equation (1) is calculated numerically. By analytically solving the above equation (1) as a primary chemical reaction equation, the following equation (2) and equation (3) representing the following concentration curve can be calculated.

Here, FIG. 3 shows density curves obtained from the above equations (3) and (4). The concentration curve represents the concentration at the height (position in the depth direction) in the tank 1 and corresponds to the concentration distribution of the organic substance concentration in the tank 1. In FIG. 3, the vertical axis represents the tank height (m), and the horizontal axis represents the organic substance concentration (g / L). Variables and constants are diffusion coefficient D = 3.0 × 10 ⁻⁵ m ² / sec, flow rate u = 1.86 × 10 ⁻⁴ m / sec, organic substance concentration C _A0 initial value = 0.9 kg / m ³ , residence time τ = 4836 sec The reaction rate constant κ = 0.2 × 10 ⁻² m ⁻¹ . As the value of the flow velocity u, the flow velocity in the tank 1 obtained by the flow velocity sensor 7 is used. As the initial value of the organic substance concentration C _A0 , the organic substance concentration in the organic waste water flowing into the tank 1 obtained by the concentration sensor 9 is used. The variables are not limited to these values, and values including values measured by experiments, values described in literatures, and the like may be set as appropriate.

Note that the above-described equation (2) is a case of a first-order reaction, and it is not preferable to apply the zero-order reaction in a region where the substrate concentration is sufficiently high. Therefore, a numerical solution by the Runge-Kutta method may be obtained by using the reaction rate κC _A ⁿ term as a Michaelis-Menten equation as shown in the following equation (5).

Here, the maximum reaction rate Vmax represents the reaction rate when the organic substance concentration C _A is infinite, and the mono-constant K _s represents a concentration that gives half the maximum rate.

  By using the mass balance equation that employs the Michaelis-Menten equation, it is possible to calculate a concentration curve when the reaction order changes. That is, whether the reaction rate is a zero-order reaction when the reaction rate does not depend on the concentration of the reactant or the reaction rate is a concentration-dependent primary reaction, the concentration curve is continuously calculated. Can do.

Here, FIG. 4 shows a density curve obtained from a numerical solution by the Runge-Kutta method. In FIG. 4, the vertical axis is the tank height (m), and the horizontal axis is the organic substance concentration (g / L). The concentration curve shown in FIG. 4 was calculated using the following variables and constants. Also, diffusion coefficient D = 3.2 × 10 ^-4 m ² / sec, flow rate u = 1.86 × 10 ^-4 m / sec, residence time τ = 4836 sec, maximum reaction rate Vmax = 2.0 × 10 ^-4 m / sec, mono constant K _s = 0.8. Note that the above variables are not limited to these values, and values including values measured by experiments, values described in literatures, and the like may be set as appropriate. Even in such a case, the density curve can be calculated by the method described above.

  Thus, the concentration curve can be calculated together with the concentration of the organic waste water or the reaction order (reaction rate) of the chemical reaction in the anaerobic treatment. Therefore, when the anaerobic treatment occurs in proportion to the organic matter concentration in the organic waste water, the concentration curve shown in FIG. 3 can be selected. On the other hand, when the anaerobic treatment occurs without being proportional to the organic matter concentration in the organic waste water, the concentration curve shown in FIG. 4 can be selected. That is, an optimal (ideal) concentration curve can be selected for anaerobic treatment of the organic wastewater flowing into the tank 1.

  According to the anaerobic treatment apparatus 100 having such a configuration, a liquid to be treated containing an organic component is introduced from the lower part in the tank 1 and flows upward while contacting the granular sludge. Thereby, the organic component of a to-be-processed liquid decomposes | disassembles with granule sludge, and an organic waste water is anaerobically processed. And by returning a part of treated water to the acid production tank 2, while being able to avoid the outflow of an acid production microbe, the organic waste water in the acid production tank 2 can be diluted.

  On the other hand, the following processing procedure (anaerobic processing method) by the control device 10 is executed in parallel with the anaerobic processing. This processing procedure will be described with reference to the flowchart shown in FIG.

  First, in step S <b> 1 (flow velocity information acquisition step), the flow velocity information acquisition unit 11 acquires flow velocity information in the tank 1 by the flow velocity sensor 7.

  Next, in step S <b> 2 (density information acquisition step), the density information acquisition unit 12 acquires density information using the density sensors 5 and 9.

  In step S3 (comparison step), the above-described concentration curve is calculated based on the flow rate information and the concentration information, and the comparison unit 13 compares the concentration curve based on the flow rate information with the concentration information. Here, as described above, for example, the concentration curve shown in FIG. 3 or FIG. 4 is selected according to the concentration of the organic waste water and the reaction order (reaction rate) of the chemical reaction in the anaerobic treatment. The concentration curve may be calculated and stored in advance based on flow velocity information and concentration information obtained from the flow velocity sensor 7 and the concentration sensor 9. When configured in this way, the comparison means can compare the concentration curve stored in advance with the measured concentration information.

  In step S4 (control step), the control means 14 enters the tank 1 so that the concentration in the tank 1 to be measured approaches the concentration given by the concentration curve based on the comparison result by the comparison means 13. To control the inflow flow rate.

  Specifically, for example, as shown in FIG. 3, the inflow flow rate into the tank 1 is controlled so that the actually measured value (■ mark) of the organic substance concentration by the concentration sensor 5 in the tank 1 approaches the concentration curve (solid line). To do. Therefore, in this embodiment, anaerobic treatment can be performed efficiently on low-concentration organic wastewater. For this reason, even if organic wastewater is low temperature, organic wastewater can be anaerobically processed efficiently.

  Moreover, in this embodiment, the line L3 which circulates and returns a part of the treated water anaerobically treated in the tank 1 is provided, and the line L3 is provided with a pump 8 for adjusting the flow rate. Treated water can be circulated. For this reason, the activity of the microorganisms that produce methane in the tank 1 can be controlled, and the organic matter concentration in the tank 1 can be controlled to an optimum value. In addition, in order to exhibit such a function, the line L3 may be connected to the downstream side of the acid generation tank 2. Even if it is a case where it comprises in this way, the treated water in the tank 1 can be circulated.

(Second embodiment)
In the second embodiment, the display device 20 is attached to the anaerobic treatment device 100. The display device 20 includes the flow velocity information acquisition unit 11, the concentration information acquisition unit 12, and the comparison unit 13 described above, and additionally includes a display unit 21.

  The display means 21 has a display, and displays the comparison result by the comparison means 13 on this display.

  According to such a display device 20, the above-described comparison result is displayed, that is, the information on the distance between the optimum concentration curve and the concentration in the tank 1 can be displayed. I can grasp it.

  The display device 20 may be used at the site where the tank 1 is installed, or may be used at a remote location away from the site. That is, the display device 20 may be configured to perform comparison at a remote place based on information related to the flow velocity or information related to the concentration transmitted via a transmission means (not shown). Or the structure which displays the comparison result transmitted via the transmission means may be sufficient as the display apparatus 20. FIG. Thus, even when the display device 20 is provided at a remote location, information on the distance between the optimum concentration curve and the concentration in the tank 1 can be displayed. Operator can grasp quickly.

  The present invention has been specifically described above based on the embodiment. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, the concentration sensor 5 is preferably used in the tank 1 as particularly preferable. Measure the organic matter concentration. However, the organic wastewater in the tank 1 may be collected and the concentration measured without using the concentration sensor 5. By measuring the concentration in this way, it is possible to measure the organic substance concentration at an arbitrary position in the tank 1, so that the organic substance concentration in the tank 1 can be accurately approximated to the concentration curve.

  Moreover, in the said embodiment, although the anaerobic processing apparatus 100 is equipped with the acid production tank 2 in the front | former stage of the tank 1, it is not limited to this. For example, when the organic acid in the organic waste water is sufficiently generated, the acid generation tank 2 may not be disposed. By comprising in this way, since the structure of the acid production | generation tank 2 can be abbreviate | omitted, anaerobic processing can be performed by simple structure. For example, depending on the type of wastewater to be treated, an adjustment tank or a mixing tank may be arranged instead of the acid generation tank 2.

  Moreover, in the said embodiment, although the flow rate of the organic waste_water | drain near the settler 6a is acquired as flow rate information, it is not limited to this. For example, the flow rate of the organic waste water at another position in the tank 1 is acquired, and the flow rate information may be information related to the flow rate (information that can be converted into the flow rate). Any information related to density (information that can be converted into density) may be used.

  Moreover, in the said embodiment, although the flow velocity information is acquired using the flow velocity sensor 7, it is not limited to this. The flow velocity information may be acquired using, for example, a flow meter. In this case, for example, the flow velocity information can be acquired by measuring the flow rate per unit area through which the organic waste water passes. Or you may acquire the opening degree of the valve | bulb provided in the piping etc. through which organic wastewater passes as flow velocity information. In this case, a value set in relation to the opening of the valve can be used as the flow velocity information. Further, the flow velocity information may be acquired by, for example, image analysis of the granule level or the flow state of the granule.

  Moreover, in the said embodiment, although density information is acquired using the density sensor 5, it is not limited to this. Concentration information may be obtained from information related to concentration such as absorbance measured using an absorptiometer, or acquired from information related to concentration such as turbidity measured using a turbidimeter. May be.

  Moreover, in the said embodiment, although the control means 14 is controlling so that the density | concentration of one place set in the tank 1 approaches the density | concentration given with a density | concentration curve, the density | concentration of several places is a density | concentration curve. You may control so that the density | concentration given may be approached. According to this, since the concentration at a plurality of locations in the tank 1 is made closer to the concentration given by the concentration curve, the concentration in the tank 1 is further brought closer to the concentration given by the concentration curve.

  In the above-described embodiment, the anaerobic treatment apparatus 100 is an EGSB type anaerobic treatment apparatus. However, the UASB (Upflow Anaerobic) has granular anaerobic sludge in which anaerobic microorganisms are self-aggregated to form fine particles. Of course, it can also be applied to a sludge blanket (upward flow anaerobic sludge bed) treatment apparatus. In short, it can be applied to an apparatus for anaerobically treating organic wastewater flowing into the tank 1 using the granular sludge bed G in the tank 1.

DESCRIPTION OF SYMBOLS 1 ... Tank (container), 2 ... Acid production tank, 5 ... Concentration sensor (concentration information acquisition means), 7 ... Flow velocity sensor (flow velocity information acquisition means), 11 ... Flow velocity information acquisition means, 12 ... Concentration information acquisition means, 13 ... Comparison means, 14 ... control means, 20 ... display device, 21 ... display means, 100 ... anaerobic treatment device.

Claims (4)

An apparatus for anaerobically treating organic wastewater flowing into a container using granular sludge in the container,
Flow rate information acquisition means for acquiring information related to the flow rate in the container;
Concentration information acquisition means for acquiring information related to the concentration in the container;
A comparison means for comparing a concentration curve based on information related to the flow velocity and information related to the concentration;
An anaerobic treatment apparatus comprising: control means for controlling an inflow rate into the container based on a comparison result by the comparison means. Comprising a line that circulates and returns part of the treated water that has been anaerobically treated in the vessel,
The anaerobic treatment apparatus according to claim 1, wherein a flow rate adjusting means for adjusting a flow rate is provided in the line. A method for anaerobic treatment of organic wastewater flowing into a container using granular sludge in the container,
A flow rate information acquisition step of acquiring information related to the flow rate in the container;
A concentration information acquisition step for acquiring information related to the concentration in the container;
Comparing a concentration curve based on information related to the flow rate and information related to the concentration;
An anaerobic treatment method comprising: a control step of controlling an inflow rate into the container based on a comparison result obtained by the comparison step. An anaerobic treatment device display device for anaerobically treating organic wastewater flowing into a container using granular sludge in the container,
A display device for an anaerobic treatment apparatus, which displays a comparison result comparing a concentration curve based on information related to a flow rate in the container and information related to a concentration in the container.

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