Anaerobic treatment apparatus and method for operating anaerobic treatment apparatus

Abstract

The present invention addresses the problem of providing: an anaerobic treatment apparatus which suppresses the occurrence of a short-circuit flow in a carrier type anaerobic treatment tank or eliminates the short-circuit flow, ensures fluidity in the anaerobic treatment tank, and suppresses the occurrence of a phenomenon associated with a decrease in treatment efficiency; and a method for operating an anaerobic treatment apparatus.　In order to solve the above problem, provided are: an anaerobic treatment apparatus which comprises a carrier type anaerobic treatment tank, a first pipe group that is composed of a plurality of pipes for introducing a fluid into the anaerobic treatment tank, and a control unit for controlling the introduction amount of the fluid introduced from the first pipe group for each pipe, wherein the control unit performs control pertaining to the introduction amount of the fluid introduced from the first pipe group so as to switch carrier flow regions in the anaerobic treatment tank; and a method for operating the anaerobic treatment apparatus.　According to the present invention, the occurrence of a short-circuit flow in a carrier type anaerobic treatment tank is suppressed or eliminated, fluidity in the anaerobic treatment tank is ensured, and the occurrence of a phenomenon associated with a decrease in treatment efficiency can be suppressed.

Description

Anaerobic treatment apparatus and operation method thereof

[0001] The present invention relates to an anaerobic treatment apparatus and an operation method thereof. More specifically, the present invention relates to an anaerobic treatment apparatus including a carrier-type anaerobic treatment tank and an operation method of this anaerobic treatment apparatus.

[0002] Generally, as a method for treating wastewater containing organic substances, 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] As such anaerobic treatment, an upflow anaerobic sludge bed method (UASB) using a treatment tank holding sludge or granules is known. Further, in order to increase the concentration of anaerobic microorganisms in the treatment tank, it is also known to use a treatment tank using a carrier (a treatment tank holding a carrier inside). In addition, a treatment tank that uses a carrier and performs anaerobic treatment is hereinafter also referred to as a "carrier-type anaerobic treatment tank" or simply an "anaerobic treatment tank".

[0004] For example, in Patent Document 1, in the treatment of treated water containing organic substances, a fluidized bed type reaction tank holding a carrier to which anaerobic microorganisms are attached inside is used, and as a fluid (water) for forming a fluidized bed, a part of the treated water from which organic substances have been removed through a fluidized type reaction tank is used. It is also described in Patent Document 1 that in order to perform the removal treatment at a high removal rate even when the concentration of organic substances in the treated water decreases, the amount of treated water supplied to the fluidized bed type reaction tank is controlled based on the concentration of organic substances in the treated water and the removal rate of organic substances.

[0005] Japanese Patent Application Laid-Open No. 2017-047398

[0006] As described in Patent Document 1, in the anaerobic treatment of treated water, when using a carrier-type anaerobic treatment tank, in this anaerobic treatment tank, it is required to maintain a high concentration of anaerobic microorganisms and to maintain and form a situation where the biofilm formed on the carrier surface and the treated water are efficiently in contact.

[0007] On the other hand, in a carrier-type anaerobic treatment tank, over time, the carriers, which have biofilms formed on their surfaces, adhere to each other. This leads to the formation of short-circuit channels within the carrier layer, where fluid can easily pass (areas where fluid has priority over others), resulting in what is known as a short-circuit flow. This reduces fluidity within the anaerobic treatment tank, ultimately causing a decrease in the contact efficiency between the carrier and the treated water (a decrease in treatment efficiency). In this case, even if the supply amount of treated water introduced into the anaerobic treatment tank is controlled, as described in Patent Document 1, the introduced treated water passes through the short-circuit channels and becomes part of the short-circuit flow, making it difficult to eliminate the short-circuit flow.

[0008] The object of the present invention is to provide an anaerobic treatment apparatus and a method for operating the anaerobic treatment apparatus that can suppress or eliminate the generation of short-circuit flow in a carrier-type anaerobic treatment tank when performing anaerobic treatment using a carrier-type anaerobic treatment tank, thereby ensuring fluidity in the anaerobic treatment tank and suppressing the occurrence of phenomena that contribute to a decrease in treatment efficiency.

[0009] As a result of diligent research into the above-mentioned problems, the inventors have discovered that, rather than increasing the flow rate supplied to a carrier-type anaerobic treatment tank, it is possible to suppress the generation of short-circuit flows within the carrier-type anaerobic treatment tank, ensure fluidity within the tank, and suppress phenomena that contribute to a decrease in treatment efficiency. Based on this discovery, the inventors have completed the present invention. That is, the present invention is the following anaerobic treatment apparatus and method for operating the anaerobic treatment apparatus.

[0010] The anaerobic treatment apparatus of the present invention, which solves the above problems, comprises a carrier-type anaerobic treatment tank, a first piping group consisting of a plurality of pipes for introducing fluid into the anaerobic treatment tank, and a control unit that controls the amount of fluid introduced from the first piping group for each pipe, wherein the control unit controls the amount of fluid introduced from the first piping group so as to switch the flow region of the carrier within the anaerobic treatment tank. According to the anaerobic treatment apparatus of the present invention, by introducing fluid into the carrier-type anaerobic treatment tank via a first piping group consisting of a plurality of pipes, and controlling the amount of fluid introduced so as to switch the flow region of the carrier within the carrier-type anaerobic treatment tank, it is possible to create a gradient in the fluid flow rate introduced into the anaerobic treatment tank and apply a localized load to the solid material (carrier) that forms the carrier layer. This makes it possible to suppress the formation of structures (short-circuit channels) that may be formed in a carrier-type anaerobic treatment tank due to adhesion between carriers with biofilms on their surfaces, or to dismantle existing structures (short-circuit channels), thereby suppressing or eliminating the generation of short-circuit channels in the carrier-type anaerobic treatment tank. In other words, it is possible to ensure fluidity in the carrier-type anaerobic treatment tank and suppress phenomena that contribute to a decrease in treatment efficiency.

[0011] Furthermore, in one embodiment of the anaerobic treatment apparatus of the present invention, the first piping group is characterized by performing gas introduction and wastewater introduction. With this characteristic, the first piping group combines the functions related to the introduction of the material to be treated into the carrier-type anaerobic treatment tank (wastewater introduction) and the introduction of fluid (especially gas introduction) to apply a local load to the solid material (carrier) that forms the carrier layer in the carrier-type anaerobic treatment tank, thereby making it possible to reduce the number of parts and save space in the apparatus.

[0012] Furthermore, one embodiment of the anaerobic treatment apparatus of the present invention is characterized by further provision of a second group of pipes, consisting of multiple pipes for introducing fluid into the anaerobic treatment tank, at a location different from the first group of pipes. This feature makes it even easier to create a gradient in the fluid flow rate introduced into the carrier-type anaerobic treatment tank, and also makes it possible to apply a locally high load to the solid material (carrier) that forms the carrier layer. As a result, it becomes even easier to suppress the formation of structures (short-circuit channels) that may be formed in the carrier-type anaerobic treatment tank by adhesion between carriers on which biofilms have formed on their surfaces, or to collapse the formed structures (short-circuit channels), and consequently, it becomes possible to quickly suppress the generation of short-circuit flow or eliminate short-circuit flow in the carrier-type anaerobic treatment tank.

[0013] Furthermore, in one embodiment of the anaerobic treatment apparatus of the present invention, the second group of piping is arranged at the bottom of the anaerobic treatment tank. With this feature, the direction of fluid flow introduced into the carrier-type anaerobic treatment tank via the second group of piping is perpendicular to the anaerobic treatment tank (upward flow). By using this upward flow in conjunction with the fluid flow introduced via the first group of piping, it becomes possible to easily switch the flow region of the carrier within the carrier-type anaerobic treatment tank and increase or fluctuate the local load intensity applied to the solid material (carrier) forming the carrier layer. This makes it even easier to suppress or eliminate short-circuit flow within the carrier-type anaerobic treatment tank.

[0014] Furthermore, one embodiment of the anaerobic treatment apparatus of the present invention is characterized in that the carrier held in the anaerobic treatment tank is activated carbon. This characteristic allows for the use of activated carbon as a carrier, which has excellent function as a carrier for attaching and supporting sludge (microorganisms), and also has a high specific gravity and settling velocity as a carrier. This makes it less likely for carrier to be washed out due to fluid introduction via the first and second piping groups or fluctuations in fluid flow rate, thus enabling the continuous and stable treatment.

[0015] Furthermore, one embodiment of the anaerobic treatment apparatus of the present invention is characterized in that the fluid introduced from the first piping group and / or the second piping group contains gas generated in the anaerobic treatment tank. This characteristic makes it possible to utilize gas (biogas) generated in the system when introducing fluid via the first and second piping groups, thereby reducing operating costs.

[0016] The present invention provides an operating method for an anaerobic treatment apparatus to solve the above problems, which is an operating method for an anaerobic treatment apparatus equipped with a carrier-type anaerobic treatment tank, comprising: a fluid introduction step of introducing fluid into the anaerobic treatment tank via a first piping group consisting of a plurality of pipes; and a control step of controlling the amount of fluid introduced into the anaerobic treatment tank via the first piping group in the fluid introduction step for each pipe, wherein the control step controls the amount of fluid introduced from the first piping group in such a way that it switches the flow region of the carrier within the anaerobic treatment tank. According to the operating method for an anaerobic treatment apparatus of the present invention, by introducing fluid into the carrier-type anaerobic treatment tank via a first piping group consisting of a plurality of pipes, and controlling the amount of fluid introduced in such a way that it switches the flow region of the carrier within the anaerobic treatment tank, it becomes possible to create a gradient in the fluid flow rate introduced into the anaerobic treatment tank and apply a localized load to the solid material (carrier) that forms the carrier layer. This makes it possible to suppress the formation of structures (short-circuit channels) that may be formed in a carrier-type anaerobic treatment tank due to adhesion between carriers with biofilms on their surfaces, or to dismantle existing structures (short-circuit channels), thereby suppressing or eliminating the generation of short-circuit channels in the carrier-type anaerobic treatment tank. In other words, it is possible to ensure fluidity in the carrier-type anaerobic treatment tank and suppress phenomena that contribute to a decrease in treatment efficiency.

[0017] According to the present invention, when performing anaerobic treatment using a carrier-type anaerobic treatment tank, it is possible to provide an anaerobic treatment apparatus and a method for operating the anaerobic treatment apparatus that can suppress or eliminate the generation of short-circuit flow within the carrier-type anaerobic treatment tank, thereby ensuring fluidity within the anaerobic treatment tank and suppressing the occurrence of phenomena that contribute to a decrease in treatment efficiency.

[0018] This is a schematic diagram illustrating an anaerobic treatment device according to the first embodiment of the present invention. This is a schematic diagram illustrating an anaerobic treatment device according to the second embodiment of the present invention. This is a schematic diagram illustrating another aspect of the anaerobic treatment device according to the second embodiment of the present invention.

[0019] In the present invention, the wastewater to be treated by the anaerobic treatment device contains organic matter and includes industrial wastewater discharged from various factories such as food processing plants, chemical plants, and paper and pulp mills, as well as domestic wastewater such as sewage. However, the wastewater is not limited to this; any wastewater containing organic matter that can be biologically treated under anaerobic conditions is subject to treatment in the present invention. Examples of such wastewater include organic wastewater containing livestock manure and sludge (excess sludge).

[0020] Hereinafter, embodiments of the anaerobic treatment apparatus and the method of operating the anaerobic treatment apparatus according to the present invention will be described in detail with reference to the drawings. The description of the method of operating the anaerobic treatment apparatus in the present invention shall be replaced by the description of the operation of the anaerobic treatment apparatus according to the present invention. The anaerobic treatment apparatus and the method of operating the anaerobic treatment apparatus described in the embodiments are merely illustrative examples for the purpose of explaining the anaerobic treatment apparatus and the method of operating the anaerobic treatment apparatus according to the present invention, and are not limited thereto.

[0021] The anaerobic treatment apparatus and operating method of the anaerobic treatment apparatus according to this embodiment relate to an anaerobic treatment apparatus and an operating method of the anaerobic treatment apparatus that biologically treat wastewater (anaerobic treatment). More specifically, the anaerobic treatment apparatus and operating method of the anaerobic treatment apparatus according to this embodiment are anaerobic treatment apparatus equipped with a carrier-type anaerobic treatment tank, which suppresses the generation of short-circuit flow within the anaerobic treatment tank, ensures fluidity within the anaerobic treatment tank, and suppresses the occurrence of phenomena that contribute to a decrease in treatment efficiency.

[0022] [First Embodiment] Figure 1 is a schematic diagram illustrating the structure of the anaerobic treatment apparatus in the first embodiment of the present invention. Figure 1A shows the overall structure of the anaerobic treatment apparatus in the first embodiment of the present invention, and Figure 1B shows the structure of the carrier-type anaerobic treatment tank and the first piping group within the structure of the anaerobic treatment apparatus in the first embodiment of the present invention.

[0023] As shown in Figure 1A, the anaerobic treatment device 1A in this embodiment comprises a carrier-type anaerobic treatment tank (hereinafter simply referred to as "anaerobic treatment tank 10") that holds a carrier C inside, a first piping group 20 consisting of a plurality of fluid introduction pipes P1 (hereinafter simply referred to as "piping P1") that introduce fluid into the anaerobic treatment tank 10, and a control unit 30 that controls the amount of fluid introduced from the first piping group 20 for each pipe. In this embodiment, wastewater W0 is introduced into the anaerobic treatment device 1A as the target for treatment, and biogas G is generated through anaerobic treatment by the anaerobic treatment tank 10, while treated water W1 is discharged outside the system. In Figure 1, the black arrows indicate the flow of wastewater W0 and treated water W1, and the white arrows indicate the flow of gas (biogas G). Also in Figure 1, the dashed-dotted arrows indicate connections that allow for control.

[0024] The anaerobic treatment tank 10 in this embodiment is not particularly limited, as long as it has a structure for performing anaerobic treatment on wastewater W0. Examples of anaerobic treatments performed in the anaerobic treatment tank 10 include methane fermentation by acid-producing bacteria and methane-producing bacteria, denitrification treatment in which nitrate and nitrite are reduced by denitrifying bacteria, and sulfate reduction treatment in which sulfuric acid is reduced by sulfate-reducing bacteria.

[0025] Furthermore, the anaerobic treatment tank 10 in this embodiment may be equipped with various additional facilities. For example, the anaerobic treatment tank 10 may be equipped with means for adjusting the internal water temperature, means for adding pH adjusters, and means for adding metals such as nitrogen, phosphorus, cobalt, and nickel, which are nutrients required by microorganisms. In particular, when methane fermentation by acid-producing bacteria and methane-producing bacteria is performed as anaerobic treatment, it is preferable to provide the anaerobic treatment tank 10 with facilities for recovering, purifying, and storing methane gas. In addition, as shown in Figure 1A, it is preferable that the anaerobic treatment tank 10 in this embodiment is equipped with a gas holder 11 for recovering and storing the biogas G produced by anaerobic treatment.

[0026] Furthermore, another reaction tank may be provided upstream of the anaerobic treatment tank 10 in this embodiment. In particular, when methane fermentation using acid-producing bacteria and methane-producing bacteria is performed as anaerobic treatment, it is known that the optimal conditions for the treatment process using acid-producing bacteria, which reduces organic matter in wastewater W0 to low molecular weight (hereinafter referred to as the "acid production process"), and the treatment process using methane-producing bacteria, which decomposes the reduced molecular weight organic matter to produce methane gas (hereinafter referred to as the "methane production process"), are different. Therefore, as shown in Figure 1A, it is preferable to provide an acid production tank 12 upstream of the anaerobic treatment tank 10 and to carry out the acid production process and the methane production process in separate tanks. The acid production tank 12 should function as a tank for carrying out the acid production process, in which wastewater W0 is introduced upstream of the anaerobic treatment tank 10, and in an anaerobic atmosphere without dissolved oxygen, the acid-producing bacteria (one of the facultative anaerobic bacteria) contained inside promote the reduction of organic matter in wastewater W0 (decomposition of organic matter) to produce organic acids. Furthermore, it is desirable that the acid generation tank 12 be a sealed system to maintain an anaerobic environment.

[0027] In this embodiment, the description will mainly focus on a configuration in which an acid generation tank 12 is provided upstream of the anaerobic treatment tank 10, but the invention is not limited to this configuration. For example, the acid generation tank 12 may be omitted, and the wastewater W0 may be directly introduced into the anaerobic treatment tank 10. Alternatively, a raw water adjustment tank or raw water storage tank may be provided further upstream of the acid generation tank 12.

[0028] Figure 1A shows an example of the arrangement and connection of the anaerobic treatment tank 10 and its surrounding equipment in this embodiment. For example, as shown in Figure 1A, the acid generation tank 12 is located upstream of the anaerobic treatment tank 10, and a line L1 for introducing wastewater W0 to the acid generation tank 12 and a line L2 for connecting to the anaerobic treatment tank 10 are provided. To the anaerobic treatment tank 10, wastewater W0 is indirectly introduced via line L2, and a line L3 is provided for discharging treated water W1 after anaerobic treatment. As for the gas holder 11, as shown in Figure 1A, a line L5 is provided for recovering the biogas G generated by anaerobic treatment in the anaerobic treatment tank 10 and introducing it into the gas holder 11, and a line L6 is provided for reintroducing a portion of the biogas G stored in the gas holder 11 back into the anaerobic treatment tank 10 via the first piping group 20, which will be described later.

[0029] Furthermore, the anaerobic treatment tank 10 of this embodiment may be provided with a structure for circulating treated water W1 within the anaerobic treatment tank 10, in consideration of improving the treatment efficiency of anaerobic treatment. For example, as shown in Figure 1A, in addition to line L3, line L4 may be provided to discharge the treated water W1 and be connected to the upstream side of the anaerobic treatment tank 10. In this case, line L4 may be connected to line L2, or it may be connected to the acid generation tank 12.

[0030] Furthermore, the anaerobic treatment tank 10 according to this embodiment holds a carrier C, and anaerobic microorganisms adhere to the surface of this carrier C, forming a biofilm, which makes it possible to retain anaerobic microorganisms involved in anaerobic treatment within the anaerobic treatment tank 10. This makes it possible to increase the concentration of anaerobic microorganisms in the anaerobic treatment tank 10 and improve the treatment efficiency related to anaerobic treatment.

[0031] (Carrier) The carrier C introduced and held in the anaerobic treatment tank 10 can be any material to which anaerobic microorganisms involved in anaerobic treatment adhere, and its structure and material are not particularly limited, however, in this embodiment, it is preferable to use a carbonaceous carrier as the carrier C. A carbonaceous carrier refers to an inorganic material whose main component is carbon, and specifically, examples include carbon black, graphite, coke, and activated carbon. In addition to being easy to mold as a carrier, carbonaceous carriers generally have a higher specific gravity than resin carriers, and have the advantage of suppressing outflow to the outside of the tank when they are flowed in the anaerobic treatment tank 10. In particular, in the anaerobic treatment device 1A of this embodiment, fluid is introduced via the first piping group 20 and the amount of fluid introduced is varied, but by using a carbonaceous carrier, carrier outflow due to such fluid introduction is less likely to occur, and stable treatment can be continued. Furthermore, while the carbonaceous carrier in this embodiment is not particularly limited in terms of whether or not it has pores, it is preferable that it has pores, in addition to being able to adsorb components that inhibit anaerobic treatment by anaerobic microorganisms (anaerobic treatment inhibitors), and specifically, it is particularly preferable to use activated carbon.

[0032] The anaerobic microorganisms attached to the carrier C in this embodiment can be any microorganism capable of anaerobic treatment of organic matter, and the specific type of microorganism is not particularly limited. For example, when methane fermentation treatment is performed as anaerobic treatment, acid-producing bacteria and methane-producing bacteria are used as anaerobic microorganisms. Other anaerobic microorganisms include denitrifying bacteria used in denitrification treatment to reduce nitrate and nitrite, and sulfate-reducing bacteria used in sulfate reduction treatment to reduce sulfuric acid. In this embodiment, isolated microorganisms may be used as anaerobic microorganisms, or seed sludge (activated sludge, digested sludge) collected from other wastewater treatment facilities may be used. Furthermore, anaerobic microorganisms contained in wastewater W0 may be utilized.

[0033] In this case, within the anaerobic treatment tank 10, the adhesion between carriers C on which a biofilm has formed on their surface can create a short-circuit channel, which is a place through which fluid can easily pass (a place through which fluid passes preferentially over other areas). When a short-circuit channel is formed, a so-called short-circuit flow occurs in the fluid flow within the anaerobic treatment tank 10. In this case, a decrease in fluidity occurs within the anaerobic treatment tank 10, which in turn leads to a decrease in the contact efficiency between the carriers and the water to be treated (a decrease in treatment efficiency).

[0034] Therefore, the anaerobic treatment device 1A in this embodiment applies a gradient to the fluid flow rate introduced into the anaerobic treatment tank 10, thereby locally increasing the load (fluid velocity) applied to the solid material (carrier C) forming the carrier layer, thereby suppressing the formation of short-circuit channels within the anaerobic treatment tank 10 or causing them to collapse, and thereby suppressing the generation of short-circuit flows within the anaerobic treatment tank 10 or eliminating short-circuit flows. More specifically, the anaerobic treatment device 1A in this embodiment applies a fluid introduction step in which fluid is introduced through a first piping group 20 consisting of a plurality of pipes P1, and a control step in which the amount of fluid introduced through the first piping group 20 is controlled in such a way that the fluid introduction step switches the flow region of the carrier within the anaerobic treatment tank 10, thereby applying a gradient to the fluid flow rate introduced into the anaerobic treatment tank and locally increasing the load (fluid velocity) applied to the carrier layer, thereby suppressing the formation of short-circuit channels within the anaerobic treatment tank 10 or causing them to collapse, and thereby suppressing the generation of short-circuit flows within the anaerobic treatment tank 10 or eliminating short-circuit flows.

[0035] The first piping group 20 in this embodiment is for performing a fluid introduction step of introducing fluid into the anaerobic treatment tank 10, and includes a plurality of pipes P1. Here, the pipes P1 can be any structure that can introduce fluid into the anaerobic treatment tank 10, for example, a tubular structure having an opening on its side for introducing fluid.

[0036] Furthermore, as a specific example of the first piping group 20 in this embodiment, as shown in Figure 1B, it comprises a plurality of pipes P1 arranged in the anaerobic treatment tank 10 and a valve V1 provided on the upstream side of each pipe P1, and the pipes P1 are merged together and connected to line L2. In other words, the first piping group 20 has a structure that connects to line L2 and branches into a plurality of pipes P1, and each pipe P1 is provided on the upstream side. Note that although there are four pipes P1 in Figure 1B, the number of pipes P1 is not limited to the number shown in Figure 1B, as long as it is a number that can create a gradient in the fluid flow rate introduced into the anaerobic treatment tank 10.

[0037] The fluid introduced from the first piping group 20 to the anaerobic treatment tank 10 may be a liquid, a gas, or a mixture of liquid and gas. While the fluid introduced from the first piping group 20 to the anaerobic treatment tank 10 may be a fluid (liquid or gas) transported from outside the system, it is preferable to use a fluid within the system from the viewpoint of reducing operating costs (transportation costs). Specific examples include wastewater W0 introduced via line L2, and biogas G introduced via line L6. In particular, by providing line L6 and using biogas G generated in the anaerobic treatment tank 10 as the fluid introduced from the first piping group 20 to the anaerobic treatment tank 10, the gas (biogas G) generated within the anaerobic treatment device 1A system can be effectively utilized, leading to an effective reduction in operating costs. In this case, the fluid introduced from the first piping group 20 to the anaerobic treatment tank 10 may be only wastewater W0, only biogas G, or a mixture of wastewater W0 and biogas G. Here, with regard to the introduction of the material to be treated (wastewater W0) into the anaerobic treatment tank 10 and the introduction of a fluid (especially gas (biogas G)) to apply a localized load to the solid material (carrier C) that forms the carrier layer within the anaerobic treatment tank 10, the first piping group 20 combines the functions related to each introduction, thereby enabling a reduction in the number of parts and space of the device.

[0038] Furthermore, lines L2 and L6 are connected via valve V2, and it is preferable, but not limited to, that the fluid introduced from the first piping group 20 is switched by switching valve V2. For example, lines L2 and L6 may be opened simultaneously, and wastewater W0 and biogas G may be introduced into the anaerobic treatment tank 10 simultaneously via the first piping group 20. Also, regarding the control of valve V2, the control unit 30, which will be described later, may adjust the fluid flow rate introduced into the anaerobic treatment tank 10 by keeping the fluid flow rate in either line L2 or line L6 constant and adjusting the fluid flow rate in the other line, thereby switching the flow region of the carrier C within the anaerobic treatment tank 10. Note that the fluid flow rate introduced into the anaerobic treatment tank 10 can be adjusted by valves V1 provided on each pipe P1 of the first piping group 20, so valve V2 only needs to have a flow path switching function, and a flow rate adjustment function is not essential.

[0039] The control unit 30 is for performing a control step of controlling the amount of fluid introduced through the first piping group 20 for each pipe P1 in order to switch the flow region of the carrier C in the anaerobic treatment tank 10. In this embodiment, the control unit 30 only needs to be able to individually control the opening and closing operations of each valve V1 provided in the first piping group 20, and may include manual operation by an operator. However, it is preferable to use a computing device (computer) that executes a program for transmitting control signals related to the opening and closing operations of the valves V1 to be controlled using a processor such as a CPU, thereby automating the series of operations by the control unit 30. This makes it possible to quickly and reliably introduce fluid in order to switch the flow region of the carrier C in the anaerobic treatment tank 10.

[0040] In this embodiment, the control content of the control unit 30 includes, for example, controlling the operation related to the driving of each valve V1 provided in the piping P1, and controlling each piping P1 (in other words, each valve V1). More specifically, this includes switching the opening / closing (ON / OFF) of the valve V1, adjusting the opening degree of the valve V1, and switching the fluid velocity (fluid flow rate) passing through the piping P1 between low velocity (low flow rate) and high velocity (high flow rate), etc., for each piping P1 (each valve V1). As a result, areas with locally high (or locally low) fluid velocity (flow rate) are formed in the anaerobic treatment tank 10, and by changing the control content related to the driving of these valves V1 (in other words, switching the operation content related to valves V1) in a short time (for example, at intervals of several minutes to several tens of minutes), the flow region of the carrier C can be switched. In other words, by creating a gradient in the fluid flow rate introduced into the anaerobic treatment tank, it is possible to apply a localized load to the solid material (carrier) forming the carrier layer, and to make the location of the load move (vary) regularly or irregularly. At this time, within the anaerobic treatment tank 10, it becomes possible to suppress the formation of structures (short-circuit channels) that may be formed by the adhesion of carriers C on which biofilms have formed on their surfaces, or to collapse the structures (short-circuit channels) that have been formed, and consequently, to suppress the generation of short-circuit flows or eliminate short-circuit flows within the anaerobic treatment tank 10.

[0041] Furthermore, the control unit 30 may also control operations related to the driving of the valve V2 connecting line L2 and line L6, and may assist in operations related to switching the fluid introduced into the anaerobic treatment tank 10 and adjusting the fluid flow rate.

[0042] As described above, in the anaerobic treatment apparatus and the operation method of the anaerobic treatment apparatus according to the present embodiment, fluid is introduced into the carrier-type anaerobic treatment tank through the first pipe group composed of a plurality of pipes, and at this time, the introduction amount of the fluid is controlled so as to switch the flow region of the carriers in the anaerobic treatment tank, thereby creating a gradient in the fluid flow rate introduced into the anaerobic treatment tank and locally applying a load to the solid matter (carriers) forming the carrier layer. As a result, regarding the structure (short-circuit flow path) that can be formed by the adhesion of carriers with biofilms formed on their surfaces in the carrier-type anaerobic treatment tank, it is possible to suppress the formation of the structure (short-circuit flow path) itself or to collapse the formed structure (short-circuit flow path). As a result, it is possible to suppress or eliminate the occurrence of short-circuit flow in the carrier-type anaerobic treatment tank. That is, it is possible to ensure the fluidity in the carrier-type anaerobic treatment tank and suppress the occurrence of phenomena involved in the reduction of treatment efficiency.

[0043] 〔Second Embodiment〕FIG. 2 is a schematic explanatory view of an anaerobic treatment apparatus according to the second embodiment of the present invention. Note that FIG. 2A shows the overall structure of the anaerobic treatment apparatus in the first embodiment of the present invention, and FIG. 2B shows the structure related to the anaerobic treatment tank, the first pipe group, and the second pipe group among the structures of the anaerobic treatment apparatus in the first embodiment of the present invention.

[0044] The anaerobic treatment apparatus 1B according to the present embodiment further includes a second pipe group 40 composed of a plurality of fluid introduction pipes P2 (hereinafter simply referred to as "pipe P2") for introducing fluid into the anaerobic treatment tank 10 at a location different from the first pipe group 20 in addition to the first pipe group 20 in the anaerobic treatment apparatus 1A of the first embodiment. In the description of the anaerobic treatment apparatus 1B according to the present embodiment, the description of the same parts as those in the first embodiment will be omitted.

[0045] As shown in Figures 2A and 2B, the anaerobic treatment apparatus 1B of this embodiment is equipped with a second piping group 40 consisting of multiple pipes P2 that introduce fluid into the anaerobic treatment tank 10, in addition to the first piping group 20, at a location different from the first piping group 20, in order to create a gradient in the fluid flow rate introduced into the anaerobic treatment tank 10 and apply a localized load to the solid material (carrier C) that forms the carrier layer. Furthermore, in the anaerobic treatment apparatus 1B of this embodiment, there are no particular limitations on the type of fluid introduced from the second piping group 40, but as shown in Figure 2A, a preferred example is to connect the line L6 through which biogas G from the gas holder 11 flows to the second piping group 40, and to use biogas G as the fluid introduced from the second piping group 40.

[0046] The second piping group 40 consists of a plurality of pipes P2. These pipes P2 may be tubular structures having openings on their sides for introducing fluid, similar to the pipes P1 in the first piping group 20 described above. However, as shown in Figure 2B, they may be tubular structures having openings at their ends for introducing fluid, and arranged to be inserted from the side wall or bottom of the anaerobic treatment tank 10. In this embodiment, a preferred example of the second piping group 40 is one in which a plurality of pipes P2 are arranged at the bottom of the anaerobic treatment tank 10, as shown in Figure 2B. This results in the fluid flow direction introduced via the second piping group 40 being vertical (upward flow) to the anaerobic treatment tank 10. By using this upward flow in conjunction with the fluid flow introduced via the first piping group 20, it becomes possible to easily switch the flow region of the carrier C within the anaerobic treatment tank 10 and increase or fluctuate the local load intensity applied to the solid material (carrier C) forming the carrier layer. This makes it even easier to suppress or eliminate short-circuit flow within the anaerobic treatment tank.

[0047] Also, when providing the second pipe group 40 at a location different from the first pipe group 20, a preferred example is to make it a location where there is no spatial overlap with the first pipe group 20 (a location with a spatial displacement in the spatial arrangement). Thereby, it becomes even easier to create a gradient in the fluid flow rate introduced into the anaerobic treatment tank 10 via the first pipe group 20 and the second pipe group 40, and it also becomes possible to locally apply a high load to the solid matter (carrier C) forming the carrier layer. That is, the formation of a short-circuit flow path in the anaerobic treatment tank 10 can be effectively suppressed, and the collapse of the short-circuit flow path can be effectively carried out, and it becomes possible to quickly suppress the generation of a short-circuit flow or eliminate the short-circuit flow in the anaerobic treatment tank.

[0048] Also, FIG. 3 is a schematic explanatory diagram showing another aspect of the anaerobic treatment apparatus according to the second embodiment of the present invention. In FIG. 3, some component illustrations are omitted to clarify the positional relationship between the first pipe group and the second pipe group. As another aspect of the second pipe group 40 in the anaerobic treatment apparatus 1B of the present embodiment, as shown in FIG. 3A, the pipe P2 may be arranged in the vertical direction along the side wall of the anaerobic treatment tank 10, or as shown in FIG. 3B, the pipe P2 may be arranged along the outer periphery of the side wall of the anaerobic treatment tank 10. In any case, by ensuring that there is no spatial overlap between the arrangement locations of the second pipe group 40 and the first pipe group 20, it becomes even easier to create a gradient in the fluid flow rate introduced into the anaerobic treatment tank 10, and it also becomes easier to locally apply a high load to the solid matter (carrier C) forming the carrier layer.

[0049] Regarding the fluid flow rate introduced from the second pipe group 40 of the present embodiment, it is preferably controlled by the control unit 30 in the first embodiment described above. At this time, as shown in FIG. 2B, a valve V3 is provided at the confluence point of the pipe P2, and the opening and closing operation is made the object of control by the control unit 30, and it may be supplied at the same flow rate throughout all of the pipes P2. Also, similar to the control content regarding the fluid flow rate introduced from the first pipe group 20, control may be performed for each pipe P2. At this time, a valve may be provided for each pipe P2 (not shown), and this valve may be made the object of control by the control unit 30.

[0050] Furthermore, the control unit 30 may be configured to make the timing of fluid introduction from the first piping group 20 and the timing of fluid introduction from the second piping group 40 different, thereby creating a time lag in the fluid introduction into the anaerobic treatment tank 10. This makes it easier to create a gradient in the fluid flow rate introduced into the anaerobic treatment tank 10, and makes it easier to apply a localized load to the solid material (carrier) forming the carrier layer.

[0051] As described above, the anaerobic treatment apparatus and the operating method of the anaerobic treatment apparatus in this embodiment further provide a second group of pipes, consisting of multiple pipes for introducing fluid into the carrier-type anaerobic treatment tank, at a location different from the first group of pipes. This makes it even easier to create a gradient in the fluid flow rate introduced into the anaerobic treatment tank, and also makes it possible to apply a locally high load to the solid material (carrier) that forms the carrier layer. As a result, it becomes even easier to suppress the formation of structures (short-circuit channels) that may be formed in the carrier-type anaerobic treatment tank by adhesion between carriers with biofilms formed on their surfaces, or to collapse existing structures (short-circuit channels). Consequently, it becomes possible to quickly suppress the generation of short-circuit flows or eliminate short-circuit flows in the carrier-type anaerobic treatment tank.

[0052] The embodiments described above are merely examples of anaerobic treatment devices and methods for operating them. The anaerobic treatment devices and methods for operating them according to the present invention are not limited to the embodiments described above, and the anaerobic treatment devices and methods for operating them according to the embodiments described above may be modified without changing the gist of the claims.

[0053] The anaerobic treatment apparatus and method of operating the anaerobic treatment apparatus of the present invention are used in the anaerobic treatment of wastewater containing organic matter, and are particularly suitable for use in an anaerobic treatment apparatus equipped with an anaerobic treatment tank utilizing a carrier (carrier-type anaerobic treatment tank) and the method of operating the anaerobic treatment apparatus.

[0054] 1A, 1B Anaerobic treatment device, 10 (carrier type) anaerobic treatment tank, 11 Gas holder, 12 Acid generation tank, 20 First piping group, 30 Control unit, 40 Second piping group, L1-L6 Lines, C Carrier, G Biogas, P1, P2 Fluid introduction piping, V1, V2, V3 Valves, W0 Wastewater, W1 Treated water

Claims

1. An anaerobic treatment apparatus comprising: a carrier-type anaerobic treatment tank; a first piping group consisting of a plurality of pipes for introducing fluid into the anaerobic treatment tank; and a control unit for controlling the amount of fluid introduced from the first piping group for each pipe, wherein the control unit controls the amount of fluid introduced from the first piping group so as to switch the flow region of the carrier within the anaerobic treatment tank.

2. The anaerobic treatment apparatus according to claim 1, characterized in that the first group of piping is used for introducing gas and introducing wastewater.

3. The anaerobic treatment apparatus according to claim 1, further comprising a second group of pipes for introducing fluid into the anaerobic treatment tank, located at a different location from the first group of pipes.

4. The anaerobic treatment apparatus according to claim 3, characterized in that the second group of piping is arranged at the bottom of the anaerobic treatment tank.

5. The anaerobic treatment apparatus according to claim 1, characterized in that the carrier held in the anaerobic treatment tank is activated carbon.

6. The anaerobic treatment apparatus according to claim 1, characterized in that the fluid introduced from the first group of piping and / or the second group of piping includes gas generated in the anaerobic treatment tank.

7. A method for operating an anaerobic treatment apparatus equipped with a carrier-type anaerobic treatment tank, comprising: a fluid introduction step of introducing fluid into the anaerobic treatment tank via a first group of pipes consisting of a plurality of pipes; and a control step of controlling the amount of fluid introduced into the anaerobic treatment tank via the first group of pipes in the fluid introduction step, wherein the control step controls the amount of fluid introduced from the first group of pipes in such a way as to switch the flow region of the carrier within the anaerobic treatment tank.

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