Processing system and processing method

Abstract

To provide a processing system and a processing method that make it possible to easily grasp an actual status of operation of the processing system and allow for stable and efficient progress of the whole process of the processing system.SOLUTION: To solve the above problem, a processing system and a processing method are provided. The processing system includes a methane fermentation tank, a membrane module, a circulation pump, detection means for detecting the blockage state of the membrane module, and microorganism concentration maintaining means for maintaining the concentration of microorganisms such as methanogens in the methane fermentation tank based on the detection results by the detection means, the detection means including means for monitoring parameters pertaining to a process of the processing system. According to this, the actual status of operation of the processing system can be easily grasped. In addition, while maintaining the methane fermentation treatment efficiency appropriately, a rapid decrease in treatment efficiency in the membrane separation can be suppressed, so that the whole process of the processing system can proceed stably and efficiently.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a treatment system and a treatment method for treating an organic substance-containing treatment target. More specifically, the present invention relates to a treatment system and a treatment method for a membrane separation methane fermentation process that combines a methane fermentation process and a membrane separation process. [Background technology]

[0002] Biological treatment using anaerobic microorganisms is widely used as a technology for treating organic substances such as organic wastewater and organic waste. In particular, methane fermentation treatment has attracted attention as a highly useful technology because it not only reduces the amount of the substance to be treated but also allows the methane produced to be used as energy.

[0003] Furthermore, solid-liquid separation is performed to separate and recover anaerobic microorganisms contained in the treated liquid after biological treatment (methane fermentation treatment), and the solid content (concentrated liquid) containing a large amount of anaerobic microorganisms is then subjected to biological treatment again. As solid-liquid separation treatments for the treated liquid after biological treatment, centrifugation using a centrifuge, sedimentation using a settling tank, dehydration using a dehydrator, and membrane separation (membrane filtration) using a membrane are known, and in particular, the combination of membrane separation and methane fermentation treatment (membrane separation methane fermentation treatment) is widely known.

[0004] For example, Patent Document 1 describes a treatment method using a fermenter and a membrane separation tank for treating high-concentration organic waste, in which methane fermentation treatment is carried out in the fermenter, the fermented sludge is circulated between the fermenter and the membrane separation tank, the fermented sludge is subjected to solid-liquid separation using a membrane separation device immersed in the membrane separation tank, and the membrane-permeated liquid that has passed through the membrane separation device is discharged outside the system, thereby maintaining the SS concentration in the fermenter at or above the effective value required to maintain methane fermentation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-24661 Summary of the Invention [Problem to be solved by the invention]

[0006] As described in Patent Document 1, membrane separation methane fermentation treatment involves subjecting the treated liquid after methane fermentation treatment to membrane separation. Therefore, if the concentration of solids (SS) in the methane fermentation tank becomes excessive in order to increase the concentration of anaerobic microorganisms (such as methane bacteria), which are greatly involved in the efficiency of methane fermentation treatment, the amount of solids contained in the treated liquid increases, making it more likely that clogging will occur in the membrane separation at the subsequent stage, resulting in problems such as the labor costs required to resolve the clogging state and a decrease in treatment efficiency due to the need to stop the entire treatment. Therefore, in membrane separation methane fermentation treatment, it is necessary to prevent a rapid decrease in treatment efficiency in membrane separation while appropriately maintaining the methane fermentation treatment efficiency.

[0007] Patent Document 1 describes that in membrane separation methane fermentation treatment, the SS concentration is considered to be equivalent to the anaerobic microorganism concentration, and the SS concentration in the methane fermentation tank is maintained at a predetermined value, thereby maintaining an appropriate methane fermentation treatment efficiency in the methane fermentation tank. On the other hand, Patent Document 1 does not specifically disclose a means for detecting SS concentration, but SS concentration is generally measured using an instrument such as an SS concentration meter (sludge concentration meter). However, instruments for measuring SS concentration have a limited measurable concentration range and problems with measurement accuracy, making it difficult to quickly and accurately grasp the SS concentration. Therefore, it is difficult to directly measure the SS concentration in a membrane separation methane fermentation process and use that value to perform stable treatment. Furthermore, Patent Document 1 does not describe at all the influence on membrane separation caused by maintaining the SS concentration at a predetermined value.

[0008] Furthermore, in a process that combines biological treatment and membrane separation, the SS concentration is not measured directly, but the viscosity of the treated liquid produced in the biological treatment tank is measured, and the solids (sludge) are extracted from the biological treatment tank so that this viscosity reaches a predetermined value, thereby improving the efficiency of the biological treatment and membrane separation. However, it is difficult to quickly and accurately measure and obtain the viscosity of the treated liquid within the treatment system.

[0009] Furthermore, in order to ensure stable and efficient operation of the entire membrane bioreactor process, it is difficult to grasp the operating status of an actual treatment system based solely on the values ​​related to the SS concentration and viscosity of the treated liquid. In other words, simply determining the values ​​related to the SS concentration and viscosity of the treated liquid in a portion of the treatment system does not necessarily provide sufficient parameters for grasping the operating status of the entire treatment system, posing challenges for stable and efficient operation of the treatment system. However, installing multiple SS concentration meters and viscometers throughout the entire treatment system not only increases costs, but also creates the problem of increasing the complexity of the treatment system, as comparing the data obtained from each meter requires correction calculations that take into account the accuracy and measurement conditions of each meter.

[0010] Therefore, in membrane separation methane fermentation treatment, it is necessary to easily grasp the actual operating conditions of the treatment system, rather than measuring the SS concentration in the methane fermentation tank or the viscosity of the treatment liquid, and to take appropriate measures based on the grasped conditions, in order to ensure smooth treatment of the entire treatment system related to membrane separation methane fermentation treatment.

[0011] An object of the present invention is to provide a treatment system that can easily grasp the actual operating status of a treatment system that performs methane fermentation treatment and membrane separation in the treatment of a material containing organic substances, and that can carry out treatment of the entire treatment system stably and efficiently, and a treatment method using this treatment system. [Means for solving the problem]

[0012] As a result of intensive research into the above-mentioned problems, the present inventors have found that, as a means for understanding the operating status of a treatment system performing methane fermentation treatment and membrane separation, a means for detecting the blockage state of a membrane module used in membrane separation is provided, and this detection means does not directly measure the physical properties of the treatment liquid, but includes a means for monitoring parameters related to the treatment system process, thereby making it possible to easily understand the actual operating status of the treatment system. Furthermore, by providing a means for maintaining the concentration of microorganisms such as methanogens in the methane fermentation treatment based on the detection results of the blockage state of the membrane module, it is possible to appropriately maintain the efficiency of the methane fermentation treatment while suppressing a rapid decrease in the treatment efficiency in membrane separation, and to enable the treatment of the entire treatment system related to membrane separation to proceed stably and efficiently, thereby completing the present invention. That is, the present invention provides the following processing system and processing method.

[0013] The treatment system of the present invention for solving the above problems is a treatment system for treating a treatment target containing organic substances, and comprises a methane fermentation tank for subjecting the treatment target to methane fermentation, a membrane module for membrane separation of the treatment liquid produced in the methane fermentation tank to obtain a concentrated liquid and a permeate liquid, a circulation pump for sending the treatment liquid to the membrane module and returning the concentrated liquid to the methane fermentation tank, a detection means for detecting a blocked state of the membrane module, and a microbial concentration maintenance means for maintaining the concentration of microorganisms in the methane fermentation tank based on the detection results by the detection means, wherein the detection means has at least one monitoring means selected from the group consisting of a means for monitoring pressure fluctuations in the circulation pump, a means for monitoring load fluctuations related to the agitation means of the methane fermentation tank, or a means for monitoring pressure difference fluctuations related to the treatment liquid inlet pressure and the concentrated liquid outlet pressure in the membrane module. According to this treatment system, in a treatment system performing methane fermentation and membrane separation, a detection means for detecting a clogged state of a membrane module used for membrane separation is provided as a means for understanding the operating status of the treatment system. This detection means includes a means for monitoring process parameters of the treatment system, such as the pressure of the circulation pump, the load on the agitation means, and the pressure difference between the inlet and outlet of the membrane module. This enables prediction and determination of the clogged state of the membrane module and facilitates understanding of the actual operating status of the treatment system. In particular, these parameters require simple operation and equipment for detection, making them preferable in terms of initial and running costs. Furthermore, by providing a microbial concentration maintenance means for maintaining the concentration of microorganisms, such as methanogens, in the methane fermentation treatment based on the detection results of the clogged state of the membrane module, it is possible to appropriately maintain the efficiency of the methane fermentation treatment while suppressing a rapid decline in the treatment efficiency of the membrane separation, thereby enabling stable and efficient treatment in the entire treatment system involving membrane separation methane fermentation.

[0014] In addition, in one embodiment of the treatment system of the present invention, the detection means has a means for monitoring load fluctuations related to the agitation means of the methane fermentation tank, and is characterized in that it monitors at least one of the current value, vibration, and temperature related to the agitation means. Generally, methane fermentation tanks are provided with agitation means for agitating the treatment liquid to homogenize the tank and increase treatment efficiency. Here, the ease of agitation varies depending on the SS concentration and viscosity of the treatment liquid, so if the SS concentration or viscosity of the treatment liquid changes, the load on the agitation means also changes. Therefore, as with this feature, by providing a means for monitoring load fluctuations associated with the agitation means of the methane fermentation tank as the detection means, it becomes possible to grasp the state of the treated liquid without directly measuring the physical properties of the treated liquid. Furthermore, it becomes possible to predict and determine whether the membrane module is clogged from the state of the treated liquid. This makes it possible to grasp the state of the treated liquid in the methane fermentation tank in addition to detecting whether the membrane module is clogged. Furthermore, by monitoring at least one of the current value, vibration, and temperature associated with the agitation means and monitoring the load fluctuations, it becomes possible to grasp the state of the treated liquid (or changes in the state) more easily and with greater accuracy than by measuring the physical properties of the treated liquid (SS concentration and viscosity).

[0015] The treatment method of the present invention for solving the above problems is a treatment method for treating a treatment target containing organic substances, and comprises: a methane fermentation process for subjecting the treatment target to methane fermentation; a membrane separation process for subjecting the treatment liquid generated in the methane fermentation process to membrane separation using a membrane module to obtain a concentrated liquid and a permeated liquid; a circulation process using a circulation pump for sending the treatment liquid to the membrane module and returning the concentrated liquid to the methane fermentation tank; a detection process for detecting a blocked state of the membrane module; and a microbial concentration maintenance process for maintaining the concentration of microorganisms in the methane fermentation tank based on the detection results from the detection process, wherein the detection process is characterized by having at least one monitoring means selected from the group consisting of a means for monitoring pressure fluctuations of the circulation pump in the circulation process, a means for monitoring load fluctuations related to the agitation means in the methane fermentation process, or a means for monitoring pressure difference fluctuations related to the treatment liquid inlet pressure and the concentrated liquid outlet pressure of the membrane module in the membrane separation process. According to this treatment method, which performs a methane fermentation process and a membrane separation process, a detection process for detecting a clogged state of a membrane module used in the membrane separation process is provided to grasp the operating status of the treatment system. This detection process includes a means for monitoring process parameters of the treatment system, such as the pressure of the circulation pump, the load on the agitation means, and the pressure difference between the inlet and outlet of the membrane module. This makes it possible to predict and determine the clogged state of the membrane module and easily grasp the actual operating status of the treatment system. In particular, these parameters require simple detection operations and devices, making them preferable in terms of initial and running costs. Furthermore, by providing a microbial concentration maintenance process for maintaining the microbial concentration in the methane fermentation process based on the detection results of the clogged state of the membrane module, it is possible to appropriately maintain the efficiency of the methane fermentation process while suppressing a rapid decline in the treatment efficiency of the membrane separation, thereby enabling the membrane separation methane fermentation process to proceed stably and efficiently. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a treatment system that can easily grasp the actual operating status of a treatment system that performs methane fermentation treatment and membrane separation in the treatment of a material containing organic substances, and that can proceed with treatment of the entire treatment system stably and efficiently, and a treatment method using this treatment system. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic explanatory diagram showing the structure of a processing system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a schematic explanatory diagram showing another aspect of a processing system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] The treatment system and treatment method of the present invention are for treating an organic substance-containing treatment target. Also, the treatment system and treatment method of the present invention are for a membrane separation methane fermentation process that combines a methane fermentation process and a membrane separation process.

[0019] Examples of materials to be treated in the present invention include organic wastewater containing solids such as food waste, food waste, vegetation, and sludge, as well as organic waste liquids and organic waste such as livestock manure and excess sludge. In particular, the materials to be treated in the present invention are preferably organic wastewater or organic wastewater that has a low solid content and contains organic substances that are easily decomposed by biological treatment. This facilitates increasing the concentration of anaerobic microorganisms in the methane fermentation treatment, and reduces the solid content in the treated liquid, making it possible to suppress the progression of membrane module blockage during membrane separation. Examples of such materials to be treated include organic wastewater and high-concentration wastewater discharged from food factories, chemical plants, etc. More specifically, examples include organic wastewater and high-concentration wastewater containing alcohols such as methanol and ethanol, glucose, glycerin, organic acids such as acetic acid, higher fatty acids, surfactants, phenols, etc. However, the object to be treated in the present invention is not limited to this, and any object containing organic matter that can be treated by methane fermentation under anaerobic conditions can be treated in the present invention.

[0020] Hereinafter, embodiments of a processing system and a processing method according to the present invention will be described in detail with reference to the drawings. The description of the processing method according to the present invention will be replaced with the description of the configuration and operation of the processing system according to the present invention. The processing system described in the embodiment is merely an example for explaining the processing system according to the present invention, and is not limited thereto. Furthermore, the processing method of the embodiment is merely an example for explaining the processing method using the following processing system, and is not limited thereto.

[0021] [Processing System] FIG. 1 is a schematic explanatory diagram showing the structure of a processing system according to an embodiment of the present invention. A treatment system 100 according to an embodiment of the present invention performs methane fermentation treatment and membrane separation treatment on a treatment target S. As shown in FIG. 1, the treatment system 100 comprises a methane fermentation tank 1 that performs methane fermentation treatment on the treatment target S supplied via a line L1, a membrane module 2 that performs membrane separation on the treated liquid W produced in the methane fermentation tank 1 to obtain a concentrated liquid F1 and a permeated liquid F2, a circulation pump 3 that sends the treated liquid W to the membrane module 2 and returns the concentrated liquid F1 to the methane fermentation tank 1, a detection means 4 that detects a blocked state of the membrane module 2, and a microbial concentration maintaining means 5 that maintains the concentration of microorganisms such as methanogens in the methane fermentation tank 1.

[0022] The treatment system 100 according to the present invention may be provided with equipment other than that shown in Fig. 1. For example, a concentration tank for concentrating the treatment target S, a solubilization tank for solubilizing the treatment target S, an adjustment tank for adjusting the amount of the treatment target S supplied to the methane fermentation tank 1, and the like may be provided upstream of the methane fermentation tank 1. Furthermore, a water treatment facility for treating the permeate F2 may be provided downstream of the membrane module 2. Furthermore, a biogas utilization facility including a desulfurization device and a gas storage tank for recovering biogas (methane gas) generated from the methane fermentation tank 1 via line L2 and utilizing this biogas may be provided.

[0023] An outline of the processing of a processing object by a processing system 100 in this embodiment will be described with reference to FIG. First, the material to be treated S is supplied to the methane fermentation tank 1 via line L1. Then, the material to be treated S is subjected to methane fermentation treatment in the methane fermentation tank 1. Then, the material to be treated S treated in the methane fermentation tank 1 becomes a treated liquid W, which is sent to the membrane module 2 side. At this time, the treated liquid W is passed through the circulation pump 3 and pipes 31a to 31d, 32a to 32c and is subjected to membrane separation through the plurality of membrane modules 2 to obtain a concentrated liquid F1 and a permeated liquid F2. The permeated liquid F2 is discharged outside the system, but the concentrated liquid F1 is returned to the methane fermentation tank 1. The above is the flow of the membrane separation methane fermentation treatment in the treatment system 100 in this embodiment. Although not shown in FIG. 1, the treatment system 100 may be provided with a line for returning the permeate F2 to the methane fermentation tank 1 so that the liquid level in the methane fermentation tank 1 does not drop.

[0024] The treatment system 100 of this embodiment is provided with a detection means 4 that detects a clogged state of the membrane module 2 used for membrane separation as a means for grasping the operating status of the treatment system 100. This detection means 4 includes at least one of monitoring means 4a to 4c that monitor parameters related to the process of the treatment system 100, such as the pressure of the circulation pump 3, the load on the agitation means 10 in the methane fermentation tank 1, and the pressure difference between the treated liquid inlet and the concentrated liquid outlet of the membrane module 2. This makes it possible to predict and determine the clogged state of the membrane module 2 and to easily grasp the actual operating status of the treatment system 100. In particular, these parameters are preferable in terms of the ease of operation and device required for detection, and in terms of initial and running costs.

[0025] Furthermore, the treatment system 100 in this embodiment is provided with a microbial concentration maintaining means 5 for maintaining the microbial concentration in the methane fermentation treatment based on the detection result of the clogging state of the membrane module 2. This makes it possible to appropriately maintain the methane fermentation treatment efficiency while suppressing a rapid decrease in the treatment efficiency in membrane separation, and allows the treatment of the entire treatment system related to membrane separation methane fermentation to proceed stably and efficiently.

[0026] Each component of the processing system 100 of this embodiment will be described below.

[0027] (methane fermentation tank) The methane fermentation tank 1 is a treatment tank for subjecting the treatment object S to methane fermentation treatment using anaerobic microorganisms (such as methane bacteria), and is preferably an airtight container to maintain anaerobic conditions, but other than that, there are no particular restrictions on the specific structure. The structure of the methane fermentation tank 1 is preferably selected appropriately depending on, for example, the material to be treated S. More specifically, the structure of a treatment tank used for the anaerobic treatment of organic wastewater or organic wastewater containing a large amount of liquid components, or the structure of a treatment tank used for the anaerobic treatment of organic waste containing a large amount of solid components, etc. can be selected and used appropriately. In the treatment system 100 of this embodiment, the treated liquid W produced in the methane fermenter 1 is supplied to the membrane module 2 for membrane separation. Therefore, when methane fermentation treatment is performed using granules in the methane fermenter 1, there is a risk that solid components with large particle diameters, such as granules, may become mixed into the treated liquid W produced in the methane fermenter 1, which may cause further clogging of the membrane module 2 arranged downstream of the methane fermenter 1. Therefore, it is preferable to perform the methane fermentation treatment using a methane fermenter 1 of a known structure as a complete mixing type methane fermenter in this embodiment.

[0028] The methane fermentation tank 1 in this embodiment is preferably provided with stirring means 10 for stirring the inside thereof. A specific configuration of the agitation means 10 is, for example, an agitator 11 equipped with an agitation blade 11a and a drive unit 11b attached to a rotation shaft as shown in Fig. 1. The agitation means 10 is also provided with a monitoring unit 4b associated with the detection means 4 described below. In the processing system 100 shown in Fig. 1, the drive unit 11b of the agitator 11 is provided with the monitoring unit 4b.

[0029] The stirring means 10 in this embodiment is not limited to the stirrer 11 having stirring blades 11a. FIG. 2 is a schematic explanatory diagram showing another aspect of the processing system in this embodiment. 2, the agitation means 10 may be configured to include an agitation pump 12 and piping 12a for circulating the treatment liquid W in the methane fermentation tank 1, instead of the agitator 11. In this case, the monitoring means 4b is provided for the agitation pump 12.

[0030] As an example of a specific structure of the methane fermenter 1, it is preferable that the bottom of the methane fermenter 1 is inclined. This makes it easier to collect the solid residue and also improves the stirring efficiency at the bottom of the methane fermenter 1. Furthermore, an example of other structures related to the methane fermentation tank 1 is one further provided with an internal structure for increasing the stirring efficiency of the stirring means 10.

[0031] In this embodiment, the material to be treated S treated in the methane fermenter 1 is sent as a treated liquid W to the membrane module 2.

[0032] (membrane module) The membrane module 2 performs solid-liquid separation (membrane separation) using a membrane on the treated liquid W produced in the methane fermenter 1 to obtain a concentrated liquid F1 and a permeated liquid F2. Furthermore, the number of membrane modules 2 in this embodiment is not particularly limited. For example, as shown in Fig. 1, a plurality of membrane modules 2a, 2b, and 2c may be arranged in series, and concentrated liquid F1 may be sequentially supplied to the membrane modules 2 to increase the concentration rate of the solid content (methane fermentation sludge) in the treated liquid W. The arrangement (arrangement) of the membrane modules 2 is also not particularly limited. For example, a plurality of membrane modules 2 may be connected in parallel to form an array, or a plurality of membrane modules 2 connected in series may be unitized, and a plurality of such units may be connected in parallel to form an array.

[0033] 1, the concentrated liquid F1 is returned to the methane fermentation tank 1 via the circulation pump 3 and pipes 31a to 31d. On the other hand, the permeated liquid F2 is discharged to the outside of the system via pipes 32a to 32c. As described above, the permeated liquid F2 discharged to the outside of the system may be further treated by other water treatment equipment.

[0034] Here, the treated liquid W sent to the membrane module 2 contains anaerobic microorganisms (methane bacteria, etc.) in the methane fermentation tank 1. In other words, when the treated liquid W is discharged from the methane fermentation tank 1 and sent to the membrane module 2, the anaerobic microorganisms (methane bacteria, etc.) are also discharged from the methane fermentation tank 1. 1, the treatment system 100 in this embodiment is equipped with a plurality of membrane modules 2a, 2b, and 2c, and circulates the treated liquid W via a circulation pump 3 and pipes 31a to 31d, and returns it to the methane fermentation tank 1 as a concentrated liquid F1, whereby anaerobic microorganisms (such as methane bacteria) that have flowed out of the methane fermentation tank 1 are recovered as the concentrated liquid F1 and returned to the methane fermentation tank 1. This prevents anaerobic microorganisms from flowing out of the methane fermentation tank 1, and makes it possible to maintain the microbial concentration in the methane fermentation tank 1.

[0035] The membrane module 2 may be any module capable of performing membrane separation of the treated liquid W to obtain a concentrated liquid F1 containing solids (methane fermentation sludge) rich in anaerobic microorganisms (such as methane bacteria) and a permeate F2 from which the solids have been removed. Specific examples of the membrane module 2 include a tubular type, a hollow fiber type, and a submerged flat membrane. As the membrane module 2 in this embodiment, it is preferable to use a so-called extra-tank type, which is installed outside the methane fermentation tank 1, as shown in FIG. 1 . It is particularly preferable to use a tubular type as the membrane module 2. The tubular type can perform membrane separation by a so-called cross-flow method, which increases the membrane surface linear velocity to generate turbulence near the membrane surface and suppresses reversible fouling. Therefore, it has the advantage that clogging of the membrane module 2 is unlikely to occur even if the treated liquid W to be fed has physical properties such as a high SS concentration and viscosity.

[0036] In this embodiment, a pressure gauge is provided at each of the treated liquid inlet and the concentrated liquid outlet of the membrane module 2, and a monitoring means 4c using the detection means 4 described below is provided. When multiple membrane modules 2 are arranged, it is sufficient that information relating to the pressure difference between the treated liquid inlet on the most upstream side of the membrane modules 2 and the concentrated liquid outlet on the most downstream side can be obtained. Specifically, as shown in Figure 1, a pressure gauge PI1 can be provided at the treated liquid inlet of the most upstream membrane module 2a, and a pressure gauge PI2 can be provided at the concentrated liquid outlet of the most downstream membrane module 2c. A monitoring means 4c is then provided for these pressure gauges PI1 and PI2.

[0037] It should be noted that a separate backwash line (not shown) may be provided for the membrane module 2.

[0038] (Circulation pump) The circulation pump 3 is used to send the treated liquid W produced in the methane fermentation tank 1 to the membrane module 2 and to return the concentrated liquid F1 to the methane fermentation tank 1. As a result, anaerobic microorganisms (such as methane bacteria) contained in the treated liquid W discharged from the methane fermentation tank 1 are returned to the methane fermentation tank 1 as the concentrated liquid F1, making it possible to suppress the outflow of anaerobic microorganisms from the methane fermentation tank 1. In Figure 1, the circulation pump 3 is shown as sending the treated liquid W produced in the methane fermentation tank 1 to the membrane module 2 (membrane module 2a) via piping 31a, and passing the concentrated liquid F1 sequentially through the membrane modules 2 (membrane modules 2b and 2c) via piping 31b to 31d, and returning it to the methane fermentation tank 1.

[0039] The circulation pump 3 is also provided with a monitoring means 4a using a detection means 4, which will be described later.

[0040] (Detection means) The detection means 4 detects whether the membrane module 2 is clogged. The detection means 4 in this embodiment does not directly measure the physical properties (SS concentration, viscosity, etc.) of the treatment liquid W when detecting the clogging state of the membrane module 2, but includes a means for monitoring parameters related to the process of the treatment system 100. This makes it possible to easily grasp the operating status of the treatment system 100 and to predict and determine the clogging state of the membrane module 2.

[0041] The detection means 4 in this embodiment is at least one selected from the group consisting of a monitoring means 4a that monitors pressure fluctuations in the circulation pump 3, a monitoring means 4b that monitors load fluctuations related to the stirring means 10 of the methane fermentation tank 1, and a monitoring means 4c that monitors pressure difference fluctuations related to the treated liquid inlet pressure and the concentrated liquid outlet pressure in the membrane module 2. The objects monitored by these monitoring means 4a to 4c are parameters related to the process of the processing system 100, and are also parameters that fluctuate with changes in the SS concentration and viscosity of the processing liquid W. Therefore, if a change occurs in the object (parameter) monitored by the monitoring means 4a to 4c, it means that a change also occurs in the SS concentration and viscosity of the processing liquid W, which makes it easier to understand the operating status of the processing system 100 and to predict or judge the clogging state of the membrane module 2.

[0042] The monitoring by the monitoring means 4a to 4c may be performed constantly while the processing system 100 is in operation, or may be performed periodically or irregularly. Furthermore, one way to predict or determine the clogged state of the membrane module 2 based on the monitoring results from the monitoring means 4a to 4c is to set a threshold value for the monitoring results in advance for each of the monitoring means 4a to 4c. For example, if any one of the monitoring results from the monitoring means 4a to 4c exceeds the threshold, it can be determined that the actual operating conditions of the treatment system 100 are such that the membrane module 2 is becoming increasingly clogged, making stable and efficient treatment difficult. Then, by taking action using the microbial concentration maintaining means 5 described below, it becomes possible to ensure stable and efficient treatment by the treatment system 100.

[0043] Each monitoring means will be explained below.

[0044] The monitoring means 4a monitors pressure fluctuations in the circulation pump 3, and examples of such monitoring means include a means for reading pressure gauges and the like provided in the circulation pump 3, and a means for transmitting and receiving pressure data from the circulation pump 3. In addition to directly obtaining pressure-related data from the circulation pump 3, a gauge such as a pressure gauge may be provided near the circulation pump 3 on the piping 31a to which the circulation pump 3 is attached, and the pressure fluctuations in the circulation pump 3 may be monitored by monitoring changes in the value of this gauge.

[0045] Here, the pressure fluctuations of the circulation pump 3 are caused by fluctuations (increases or decreases) in the SS concentration and viscosity of the treatment liquid W supplied from the methane fermentation tank 1. For example, when the treatment liquid W is being pumped by the circulation pump 3, if a higher pressure is required for the liquid to be pumped than before (if the monitoring means 4a detects a pressure fluctuation indicating an increase in the pressure of the circulation pump 3), it can be determined that the viscosity or SS concentration of the treatment liquid W has increased. In other words, it can be determined that the operating conditions are such that a blockage in the membrane module 2 is likely to occur.

[0046] The monitoring means 4 b monitors the load fluctuations associated with the agitation means 10 of the methane fermenter 1 . For example, when the stirring means 10 is composed of an agitator 11 as shown in FIG. 1, the "load" related to the stirring means 10 refers to the force (resistance force) applied to the rotational force of the stirring means 10 (agitator 11), and more specifically refers to the torque load of the stirring means 10 (agitator 11). Therefore, the monitoring means 4b may be any means capable of monitoring the torque load fluctuation of the agitator 11, and may, for example, be configured to select at least one of the current value, vibration, and temperature of the agitator 11 as the monitoring target and monitor it. More specifically, for example, the current value, vibration, and temperature of the drive unit 11b of the agitator 11 may be measured by using a function originally provided in the drive unit 11b or by providing a measuring instrument. Note that "vibration" here includes vibration velocity, vibration rate, frequency analysis, etc. More specifically, the current value can be measured by providing an ammeter to the drive unit 11b or by using a current input / output means provided in the drive unit 11b. Furthermore, the vibration can be measured by using a contact vibrometer or a non-contact vibrometer using low to high frequency bands in the drive unit 11b. Note that a vibrometer using a high frequency band can also detect damage to the drive unit 11b. Furthermore, the temperature can be measured by providing a temperature sensor to the drive unit 11b or by providing a device that can output detected heat to the outside, such as an infrared camera.

[0047] Here, the load fluctuation of the agitation means 10 is caused by fluctuations (increases or decreases) in the SS concentration and viscosity of the treatment liquid W in the methane fermentation tank 1. For example, if the current value required by the drive unit 11b becomes higher than before during agitation by the agitation means 10 (agitator 11), it can be determined that the viscosity or SS concentration of the treatment liquid W in the methane fermentation tank 1 has increased. In other words, it can be determined that the operating conditions are such that clogging of the membrane module 2 is likely to occur.

[0048] 2, the "load" of the agitation means 10 refers to the force required to drive the agitation means 10 (agitation pump 12), and more specifically, refers to the output load of the drive unit of the agitation means 10 (agitation pump 12). The monitoring means 4b is sufficient as long as it monitors the load fluctuation of the agitation pump 12, and the monitoring target is selected from at least one of the pressure, current value, vibration, and temperature related to the agitation pump 12. This makes it possible to grasp the operating status of the treatment system 100 and determine whether the membrane module 2 is clogged, just like the agitator 11.

[0049] The monitoring means 4c monitors fluctuations in the pressure difference between the treated liquid inlet pressure and the concentrated liquid outlet pressure of the membrane module 2. As shown in Fig. 1, for example, the monitoring means 4c acquires the value of a pressure gauge PI1 provided on the treated liquid inlet side (on the pipe 31a) of the membrane module 2a and the value of a pressure gauge PI2 provided on the concentrated liquid outlet side (on the pipe 31d) of the membrane module 2c, and calculates the pressure difference between them.

[0050] Here, fluctuations in the pressure difference between the inlet and outlet of the membrane module 2 are caused by fluctuations (increases or decreases) in the SS concentration and viscosity of the treated liquid W supplied from the methane fermentation tank 1, as well as by the progression of clogging of the membrane module 2. For example, when fluctuations in the pressure difference between the treated liquid inlet pressure and the concentrated liquid outlet pressure in the membrane module 2 occur, it can be determined that the clogging of the membrane module 2 is progressing and that the viscosity or SS concentration of the treated liquid W is increasing.

[0051] It is sufficient that at least one of the monitoring means 4a to 4c is provided as the detection means 4. Therefore, any one of the monitoring means 4a to 4c may be selected, or a plurality or all of the monitoring means 4a to 4c may be provided.

[0052] In particular, the detection means 4 in this embodiment preferably includes at least a monitoring means 4b for load fluctuations associated with the agitation means 10 of the methane fermentation tank 1. This makes it possible to grasp the state of the treated liquid W in the methane fermentation tank 1 in addition to detecting the blockage state of the membrane module 2. Furthermore, by monitoring at least one of the current value, vibration, and temperature associated with the agitation means 10 and monitoring the load fluctuations, it becomes possible to grasp the state (or changes associated with the state) of the treated liquid W more simply and with higher accuracy than by measuring the physical properties (SS concentration and viscosity) of the treated liquid W.

[0053] If the detection means 4 detects that the membrane module 2 is blocked or that the blocking state of the membrane module 2 is progressing, continuing to operate the treatment system 100 under these conditions will cause problems in the operation of the treatment system 100. Therefore, based on the detection results of the blockage state of the membrane module 2 by the detection means 4, measures can be taken to stabilize the operation of the treatment system 100, and the progression of the membrane module 2 to a blockage state can be suppressed without the objects monitored by the monitoring means 4a to 4c exceeding the threshold value. More specifically, for example, in the case of the monitoring means 4a, when the pressure fluctuation of the circulation pump 3 is on an upward or downward trend, the monitoring means 4a adjusts the physical properties of the treated liquid W or the treatment state and treatment conditions of the treated liquid W so that the pressure fluctuation difference falls within a certain range. In particular, the monitoring means 4a makes adjustments to maintain the concentration of microorganisms (such as methane bacteria) in the methane fermenter 1, preventing the SS concentration and viscosity of the treated liquid W from becoming excessively high or low, and allowing stable methane fermentation treatment to proceed in the methane fermenter 1. This makes it possible to appropriately maintain the methane fermentation treatment efficiency while suppressing progression to a clogged state in membrane separation, thereby suppressing a rapid decrease in treatment efficiency, and enabling stable and efficient treatment in the entire treatment system related to membrane separation methane fermentation.

[0054] (Means for maintaining microorganism concentration) The microbial concentration maintaining means 5 is a means for maintaining the concentration of microorganisms in the methane fermentation tank 1, and is operated based on the detection results obtained by the detection means 4. The "microorganisms in the methane fermentation tank 1" that are the target of the microbial concentration maintaining means 5 include all microorganisms involved in methane fermentation. More specifically, examples of the microorganisms in the methane fermentation tank 1 include methanogens, as well as microorganisms involved in breaking down organic substances into smaller molecules, hydrolysis, or acid production.

[0055] The microbial concentration maintaining means 5 may be any means capable of maintaining a constant microbial concentration in the methane fermentation tank 1. For example, the microbial concentration may be maintained by controlling the activity of methanogens and the like in the methane fermentation tank 1 by controlling the treatment conditions of the methane fermentation tank 1 (addition of nutrient sources for the microorganisms, temperature, stirring conditions, etc.), or by withdrawing methane fermentation sludge from the methane fermentation tank 1. As the microbial concentration maintaining means 5 in this embodiment, from the viewpoint of being easy to operate and capable of maintaining the microbial concentration with a certain degree of accuracy, an example will be given and explained in which methane fermentation sludge is extracted from the methane fermentation tank 1.

[0056] As shown in Fig. 1, the microbial concentration maintaining means 5 comprises a pipe 51 branched from the pipe 31a and an extraction unit 52 provided on the pipe 51. The specific structure of the extraction unit 52 is not particularly limited as long as the extraction operation is controlled in accordance with the detection result of the detection means 4. For example, as shown in Fig. 1, it may comprise a combination of a flow rate adjusting valve and a liquid feed pump provided on the pipe 51.

[0057] The amount of methane fermentation sludge extracted by the extraction unit 52 corresponds to the detection result of the detection means 4. More specifically, the extraction unit 52 extracts methane fermentation sludge continuously or intermittently so that the fluctuation range of the monitored object falls within a certain range in the monitoring means 4a to 4c of the detection means 4. This makes it possible to appropriately maintain the microbial concentration in the methane fermentation tank 1, and to appropriately maintain the methane fermentation treatment efficiency while suppressing a rapid decrease in treatment efficiency in membrane separation, allowing the treatment in the membrane separation methane fermentation treatment system 100 as a whole to proceed stably and efficiently.

[0058] 1, the microbial concentration maintaining means 5 in this embodiment is not limited to being provided on a pipe 31a that connects the methane fermentation tank 1 and the membrane module 2 (membrane module 2a) and supplies the treated liquid W discharged from the methane fermentation tank 1 to the membrane module 2 (membrane module 2a). Another example is, for example, a pipe 51 and an extraction section 52 that branch off from a pipe 31d that connects the membrane module 2 (membrane module 2c) and the methane fermentation tank 1 and supplies a concentrated liquid F1 from the membrane module 2 (membrane module 2c) toward the methane fermentation tank 1, and that extracts methane fermentation sludge from the concentrated liquid F1.

[0059] The above-described embodiment shows an example of a processing system and a processing method. The processing system and processing method according to the present invention are not limited to the above-described embodiment, and the processing system and processing method according to the above-described embodiment may be modified within the scope of the gist of the claims. [Industrial Applicability]

[0060] The treatment system and treatment method of the present invention are used to treat organic substances, such as organic wastewater and organic waste, etc. The treatment system and treatment method of the present invention are particularly suitable for use in methane fermentation treatment and membrane separation methane fermentation treatment using membrane separation. [Explanation of symbols]

[0061] 100 treatment system, 1 methane fermentation tank, 10 stirring means, 11 agitator, 11 a stirring blade, 11 b drive unit, 12 stirring pump, 12 a piping, 2, 2a, 2b, 2c membrane module, 3 circulation pump, 31 a to 31 d piping, 32 a to 32 c piping, 4 detection means, 4 a to 4 c monitoring means, 5 microbial concentration maintenance means, 51 piping, 52 withdrawal unit, F1 concentrated liquid, F2 permeate, L1, L2 lines, PI1, PI2 pressure gauges, S treatment object, W treatment liquid

Claims

1. A treatment system for treating an object to be treated that contains organic matter, a methane fermentation tank for subjecting the material to methane fermentation; a membrane module that separates the treated liquid produced in the methane fermentation tank through membrane separation to obtain a concentrated liquid and a permeated liquid; a circulation pump that sends the treated liquid to the membrane module and returns the concentrated liquid to the methane fermentation tank; a detection means for detecting a blocked state of the membrane module; a microbial concentration maintaining means for maintaining a concentration of microorganisms in the methane fermentation tank based on the detection result by the detection means, The detection means a means for monitoring pressure fluctuations in the circulation pump; Or, a means for monitoring load fluctuations related to the agitation means of the methane fermentation tank, Alternatively, a treatment system characterized by having at least one monitoring means selected from the group consisting of monitoring means for fluctuations in the pressure difference between the inlet pressure of the treated liquid and the outlet pressure of the concentrated liquid in the membrane module.

2. A treatment system for treating an object to be treated that contains organic matter, a methane fermentation tank for subjecting the material to methane fermentation; a plurality of membrane modules for subjecting the treated liquid produced in the methane fermentation tank to membrane separation to obtain a concentrated liquid and a permeated liquid; a circulation pump that sends the treated liquid to the membrane module and returns the concentrated liquid to the methane fermentation tank; a detection means for detecting a blocked state of the membrane module; a microbial concentration maintaining means for maintaining a concentration of microorganisms in the methane fermentation tank based on the detection result by the detection means, the plurality of membrane modules are arranged to supply a concentrate to a downstream membrane module; The treatment system is characterized in that the detection means has a means for monitoring fluctuations in the pressure difference between the treatment liquid inlet pressure at the most upstream side of the plurality of membrane modules and the concentrated liquid outlet pressure at the most downstream side of the plurality of membrane modules.

3. A treatment method for treating an object to be treated that contains organic substances, comprising: a methane fermentation step of subjecting the material to be treated to methane fermentation; a membrane separation step in which the treated liquid produced in the methane fermentation step is subjected to membrane separation using a membrane module to obtain a concentrated liquid and a permeated liquid; a circulation step using a circulation pump to send the treated liquid to the membrane module and return the concentrated liquid to the methane fermentation tank; a detection step of detecting a clogged state of the membrane module; a microbial concentration maintaining step of maintaining a concentration of microorganisms in the methane fermentation tank based on the detection result from the detection step, The detection step includes: a means for monitoring pressure fluctuations in the circulation pump during the circulation process; Or, a means for monitoring load fluctuations related to the agitation means in the methane fermentation process, Alternatively, a treatment method characterized by using at least one monitoring means selected from the group consisting of monitoring means for fluctuations in the pressure difference between the inlet pressure of the treated liquid and the outlet pressure of the concentrated liquid of the membrane module in the membrane separation process.

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