JP7236890B2 - Garbage disposal device and garbage disposal method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a garbage disposal apparatus and a garbage disposal method for fermenting garbage.

Conventionally, attempts have been made to treat organic waste such as food waste by fermentation technology, not only to reduce the amount of waste, but also to utilize gases such as methane produced by the fermentation process. With such technology, the efficiency of treatment depends on the action of microorganisms such as methanogens, making it difficult to control.

For example, Japanese Patent Application Laid-Open Nos. 2018-103079 (Patent Document 1) and 2006-224090 (Patent Document 2) provide two fermenters with different temperatures to achieve practical processing speed and controllability. A compatible technique is disclosed.

JP 2018-103079 A JP 2006-224090 A

However, in the technology of Patent Document 1, the temperature in the first fermenter is 30 to 40 ° C., the temperature in the second fermenter is up to 45 ° C., and the technology of Patent Document 1 is applied. was limited to the fermentation process performed in the so-called mesophilic fermentation area. In addition, the application of the technique of Patent Document 2 was also limited to the fermentation process performed in the area of mesophilic fermentation. This is because the techniques of Patent Documents 1 and 2 are still insufficient in terms of technology for controlling the fermentation process, and are difficult to apply to high-temperature fermentation, in which the operation tends to be particularly unstable.

Therefore, it is desired to realize a food waste disposal apparatus and a food waste disposal method that are applicable to high-temperature fermentation and have high controllability.

The garbage disposal apparatus according to the present invention is characterized by a crushing unit capable of crushing garbage, a storage unit capable of storing a garbage treatment liquid containing the crushed garbage, and the storage unit. a stirring unit capable of stirring the garbage treatment liquid stored in the storage unit; a transfer unit capable of transferring the garbage treatment liquid stored in the storage unit; a fermentation processing unit capable of receiving and fermenting the processed garbage liquid; and an inspection unit capable of inspecting the processed garbage liquid fermented in the fermentation processing unit, wherein the stirring unit and A pump is provided as the transfer section, the upstream side of the pump is in fluid communication with the storage section, the downstream side of the pump is in fluid communication with the fermentation processing section and the storage section, and the inspection section A collecting unit capable of collecting a part of the treated food waste liquid fermented in the fermentation processing unit and storing it in a sample tank different from the fermentation processing unit, wherein the inspection is carried out by collecting the liquid in the sample tank. This is performed on the garbage treatment liquid, and the transferring section controls the transfer of the garbage treatment liquid to the fermentation treatment section based on the result of the inspection performed by the inspection section.

In addition, the characteristic configuration of the food waste disposal method according to the present invention includes a crushing treatment step of crushing food waste, a storage step of storing a food waste treatment liquid containing the crushed food waste in a storage unit , a stirring step of circulating the garbage treatment liquid stored in the reservoir through a stirring channel by a pump to maintain a dispersed state of the garbage treatment liquid; a transfer step of transferring to a fermentation processing section by the pump ; a fermentation processing step of fermenting the treated food waste liquid transferred to the fermentation processing section; and processing of the food waste fermented in the fermentation processing section. an inspection step of storing a part of the liquid in a sample tank different from the fermentation processing unit and performing an inspection, and in the transfer step, the transfer of the garbage treatment liquid is controlled based on the result of the inspection. It is in the point to do.

According to these configurations, it is possible to realize a garbage disposal apparatus and a garbage disposal method having high controllability. Therefore, the garbage disposal apparatus and the garbage disposal method according to the present invention can also be applied to high-temperature fermentation, so that it is easy to increase the ability to treat garbage. However, the application of the present invention is not limited to high-temperature fermentation, and high controllability can be exhibited even in mesophilic fermentation.
According to this configuration, the inspection section can be maintained and inspected without interrupting the fermentation process.
According to this configuration, it is easy to keep the state of the garbage treatment liquid stored in the storage unit uniform.
It is easier to increase the controllability of the fermentation process.
With this configuration, one pump can serve as both the transfer section and the agitation section.
can be

Preferred embodiments of the present invention are described below. However, the scope of the present invention is not limited by the preferred embodiments described below.

A further characteristic configuration of the garbage processing apparatus according to the present invention is that the inspection unit can measure the pH of the garbage treatment liquid, and the transfer unit performs the fermentation process based on the pH of the garbage treatment liquid. The point is to control the transfer of the garbage treatment liquid to the part.

According to this configuration, it is possible to measure the pH, which is correlated with the production of organic acids, which is important as a factor inhibiting methane fermentation, so that it is easier to improve the controllability of the fermentation process.

A further characteristic configuration of the food waste treatment apparatus according to the present invention comprises at least two of said pumps, the upstream side of each pump being in fluid communication with said storage section, and the downstream side of each pump being in fluid communication with said fermentation processing section and said It is in fluid communication with the reservoir.

According to this configuration, both of the two pumps can serve as both the transfer section and the stirring section. Therefore, even if one of the pumps cannot operate due to a failure or the like, the operation of the garbage processing apparatus is stopped. Maintenance work can be performed without

A further characteristic configuration of the garbage disposal apparatus according to the present invention is that the operation of the pump is controlled based on the result of the inspection.

According to this configuration, the operation of the pump for transporting the garbage treatment liquid can be controlled based on the inspection result, so that the controllability of the fermentation treatment can be easily improved.

A further characteristic configuration of the garbage disposal apparatus according to the present invention is that the fermentation treatment in the fermentation treatment section is performed at 50° C. or higher.

According to this configuration, it is easy to increase the ability to dispose of garbage.

Further features and advantages of the invention will become clearer from the following description of exemplary and non-limiting embodiments described with reference to the drawings.

1 is a configuration diagram of a garbage disposal apparatus according to an embodiment; FIG. It is a figure showing the control system of the garbage processing apparatus which concerns on embodiment.

An embodiment of a garbage disposal apparatus and a garbage disposal method according to the present invention will be described with reference to the drawings. An example in which the garbage disposal apparatus according to the present invention is applied to a garbage disposal apparatus 100 for fermenting garbage discharged from a food factory to generate biogas will be described below.

[Structure of Garbage Disposal Device]
First, the configuration of the garbage disposal apparatus 100 according to this embodiment will be described. The garbage processing apparatus 100 includes a disposer unit 1 (an example of a crushing unit) capable of crushing garbage D, and a storage tank 2 (an example of a storage unit) capable of receiving and storing the garbage treatment liquid DW from the disposer unit 1. , a pump 3A and a pump 3B capable of feeding the garbage-treated liquid DW from the storage tank 2, a fermentation tank 4 capable of fermenting the garbage-treated liquid DW (an example of the fermentation section), and a garbage-treated liquid from the fermentation tank 4. A pH measurement unit 5 (an example of an inspection unit) capable of collecting a DW sample and measuring the pH of the sample, and a consumption facility 6 capable of consuming the biogas produced in the fermentation tank 4 are provided (Fig. 1).

The disposer unit 1 has a hopper 11 capable of receiving the food waste D, a crusher 12 capable of crushing the food waste D, and a liquid feed pump 13 capable of feeding the food waste treatment liquid DW. Garbage D thrown into the hopper 11 falls by its own weight into a crusher 12 provided below the hopper 11 . The hopper 11 is provided with an agitator 14 for preventing clogging (bridging) of the garbage D, and a screw feeder 15 for conveying the garbage D to the crusher is provided below the hopper 11 . The garbage D that has fallen into the crusher 12 is crushed by the crusher 12 and then mixed with water W to form the garbage treatment liquid DW. The garbage treatment liquid DW is sent to the storage tank 2 by the liquid sending pump 13 .

The storage tank 2 has a receiving port 21 that can receive the garbage treatment liquid DW sent from the disposer unit 1 (liquid sending pump 13), and a delivery port 22 that can send the garbage treatment liquid DW to the pumps 3A and 3B. , and a return receiving port 23 capable of receiving the garbage treatment liquid DW returned from the pumps 3A and 3B.

Pumps 3A and 3B are provided on the downstream side of the storage tank 2 (outlet 22) as shown in FIG. A pipe 31 connected to the delivery port 22 branches into a pipe 31A connected to the upstream side of the pump 3A and a pipe 31B connected to the upstream side of the pump 3B. Pipes 32A, 32B connected downstream of the pumps 3A, 3B branch into pipes 33A, 33B directed to the fermentation tank 4 and pipes 34A, 34B directed to the storage tank 2 . The pipe 33A and the pipe 33B merge and are connected as the pipe 33 to the fermentation tank 4 (receiving port 41). The pipe 34A and the pipe 34B merge and are connected as a pipe 34 to the storage tank 2 (return receiving port 23). Valves 35A and 35B are provided on the pipes 33A and 33B, and valves 36A and 36B are provided on the pipes 34A and 34B.

Under normal conditions, one of the pumps 3A and 3B is operated as an agitation pump and the other as a transfer pump. In the following description, an example will be described in which the pump 3A is operated as a stirring pump and the pump 3B is operated as a transfer pump.

To operate pump 3A as an agitation pump, valve 35A is closed and valve 36A is open. Therefore, the fluid communication flow path ( A stirring channel) is formed.

Since the food waste treatment liquid DW is a dispersion liquid in which solid food waste is dispersed in water, the food waste gradually settles when left standing. Since sedimented food waste can cause clogging, etc., it is necessary to periodically stir the food waste treatment liquid DW to maintain the state of the dispersion liquid. In the garbage disposal apparatus 100 of the present embodiment, the pump 3A is periodically operated to circulate the garbage treatment liquid DW through the agitation passage, thereby maintaining the garbage treatment liquid DW dispersed. That is, the agitation flow path described above functions as an agitator in the garbage disposal apparatus 100 .

On the other hand, to operate the pump 3B as a transfer pump, the valve 35A is opened and the valve 36A is closed. Therefore, the storage tank 2 (delivery port 22), the pipe 31, the pipe 31B, the pump 3B, the pipe 32B, the valve 35B, the pipe 33B, the pipe 33, and the fermentation tank 4 (receiving port 41) are fluidly communicated in this order. channel) is formed.

Furthermore, a pump control section 37 (FIG. 2) is provided for controlling the operation and stop of the pumps 3A and 3B.

Both of the pumps 3A and 3B can operate as a stirring pump and a transfer pump. Therefore, even if one of the pumps breaks down, for example, the other non-broken pump can be used as an agitation pump and a transfer pump, so the operation of the garbage disposal apparatus 100 can be continued.

In the garbage disposal apparatus 100 of the present embodiment, the pump 3B is periodically operated to transfer the treated garbage DW from the storage tank 2 to the fermentation tank 4 through the transfer passage. In other words, the transfer channel functions as a transfer section in the garbage disposal apparatus 100 .

The fermentation tank 4 has a receiving port 41 for receiving the treated garbage DW transferred from the storage tank 2, an agitator 42 for stirring the treated garbage DW in the tank, and a pH of the treated garbage DW in the tank. It has a sampling port 43 that can be sampled by the measuring unit 5 and a gas outlet 44 that can deliver the biogas generated in the tank to the consuming facility 6 . Microorganisms such as methane bacteria are present in the fermentation tank 4, and ferment the garbage contained in the garbage treatment liquid DW to generate biogas containing methane. The inside of the fermentation tank 4 is maintained at 53 to 55° C. suitable for fermentation by a temperature maintenance device (not shown).

The stirrer 42 is provided for the purpose of making uniform the dispersed state and temperature of the garbage to be fermented by stirring the garbage treatment liquid DW in the tank. The stirrer 42 is controlled by a timer to operate intermittently.

The pH measurement unit 5 includes a collection pump 51 capable of collecting the treated garbage DW from the fermentation tank 4, a sample tank 52 (example of a collection unit) capable of storing the collected treated garbage DW, and the raw garbage in the sample tank 52. It has a pH measuring device 53 capable of measuring the pH of the waste treatment liquid DW and a gate valve 54 . Each part of the pH measuring part 5 is provided above the liquid surface of the fermentation tank 4 .

Since the pH measuring device 53 is configured not to directly measure the pH of the treated garbage DW in the fermentation tank 4 but to measure the pH of the treated garbage DW collected in the sample tank 52, There is an advantage that maintenance of the pH measuring device 53 is easy. The pressure inside the fermentation tank 4 becomes higher than the atmospheric pressure due to the generated biogas. Therefore, if the pH measuring device 53 is directly installed in the fermentation tank 4, the fermentation tank 4 must be depressurized in order to maintain the pH measuring device 53. need. However, in the present embodiment, the pH measuring device 53 can be maintained by depressurizing only the sample tank 52 after the communication between the fermentation tank 4 and the sample tank 52 is cut off by the gate valve 54. Therefore, it is necessary to depressurize the fermentation tank 4. There is no

The consumption facility 6 may be a known facility capable of consuming methane, such as a boiler, generator, cogeneration facility, flare stack, or the like. If the consumption facility 6 is a facility that utilizes heat, such as a boiler or a cogeneration facility, the heat generated by the consumption facility 6 can be used in the temperature maintenance device of the fermentation tank 4 .

[Control of Garbage Disposal Device]
Next, a control method for the garbage disposal apparatus 100 according to this embodiment will be described. As a premise for this, first, the influence of organic acids, which is one of the factors inhibiting the fermentation process performed in the fermentation tank 4, will be described.

Fermentation of food waste consists of the steps in which proteins contained in food waste are hydrolyzed into small molecules such as amino acids and sugars by enzymes, the step in which organic acids are generated from amino acids and sugars by acid-producing bacteria, and the following steps. a stage in which methane is produced from the organic acid by methanogenic bacteria. Here, when the production rate of organic acid by acid-producing bacteria exceeds the consumption rate of organic acid by methanogenic bacteria, excess organic acid accumulates in the tank, resulting in a decrease in pH. Since the optimum pH for the activity of methanogens is 7 to 8, when the pH drops due to the accumulation of organic acids, the activity of methanogens decreases and the rate of consumption of organic acids further decreases, resulting in a further decrease in pH. That is, when the pH in the tank drops to some extent, a vicious cycle occurs in which the activity of methanogenic bacteria decreases due to the pH decrease and the pH decreases due to the accumulation of organic acids, and the fermentation process does not proceed.

In order to avoid such a situation, it is effective to take measures to inhibit the production of the organic acid when signs of excessive organic acid are observed. Specifically, it is effective to reduce or stop the supply of new organic matter, that is, new garbage, which is the source of organic acid generation. By taking such measures, the rate of organic acid consumption by methanogenic bacteria exceeds the rate of organic acid production by acidogenic bacteria, and an excessive decrease in pH can be suppressed.

In order to realize such control, in the garbage disposal apparatus 100, based on the pH (example of inspection result) of the garbage treatment liquid DW measured by the pH measuring unit 5 (pH measuring device 53), the transfer pump to control the operation of the pump 3B operated as

First, the operation cycle of the pumps 3A and 3B during normal operation when the pH of the garbage treatment liquid DW is 7.4 or higher will be described. First, the pump 3A (stirring pump) is operated for 30 minutes in order to make the garbage treatment liquid DW in the storage tank 2 uniformly dispersed. Next, in order to transfer the uniformly dispersed garbage treatment liquid DW to the storage tank 2, the pump 3B (transfer pump) is operated for 15 minutes. After that, one cycle ends after a 15-minute pump rest period. As long as the pH of the garbage treatment liquid DW is 7.4 or more, the cycle of the stirring operation (30 minutes), the transfer operation (15 minutes), and the pause period (15 minutes) is repeated.

Secondly, the operation cycle of the pumps 3A and 3B when the pH of the garbage treatment liquid DW is 7.2 or more and less than 7.4 will be described. First, the stirring operation for 30 minutes is the same as usual. The transfer run is then carried out for half the normal time, ie 7.5 minutes. After that, the rest period is extended by the shortened transfer operation, and one cycle ends after the rest period of 22.5 minutes. As long as the pH of the garbage treatment liquid DW is 7.2 or more and less than 7.4, the above cycle of stirring operation (30 minutes), transfer operation (7.5 minutes), rest period (22.5 minutes) is repeated. .

Thirdly, the operation cycle of the pumps 3A and 3B when the pH of the garbage treatment liquid DW is less than 7.2 will be described. When the pH of the garbage treatment liquid DW is less than 7.2, the transfer operation is not performed in order to stop the generation of organic acid and wait for the pH to recover. Therefore, the cycle is a 30-minute stirring operation and a 30-minute pause period, which is the same as the normal time. In this manner, the supply of food waste is stopped to restore the pH, and when the pH is restored to 7.2 or higher, the transfer of the food waste treatment liquid DW is resumed.

In order to realize such control of transfer according to pH, the pH measurement unit 5 performs pH measurement at a timing corresponding to the operation cycle. Specifically, for example, immediately before the stirring operation of each cycle is started, the sampling pump 51 is operated to sample the latest garbage treatment liquid DW in the sample tank 52 to measure the pH, and the transfer operation in the cycle is performed. determine the length of

By controlling as described above, it is possible to suppress the production of organic acids in a stage where the decrease in pH is mild, and to prevent the pH from decreasing to a level at which methanogenic bacteria lose their activity.

[Other embodiments]
Finally, other embodiments of the garbage disposal apparatus and the garbage disposal method according to the present invention will be described. It should be noted that the configurations disclosed in the respective embodiments below can also be applied in combination with configurations disclosed in other embodiments unless there is a contradiction.

(1) In the above-described embodiment, the configuration in which the garbage disposal apparatus 100 includes the pH measurement unit 5 has been described as an example. However, without being limited to such a configuration, in the garbage disposal apparatus according to the present invention, the inspection unit inspects, for example, the temperature, turbidity, specific gravity, conductivity, liquid level, etc. of the garbage disposal liquid. may be configured to be executable. In addition, the garbage processing apparatus according to the present invention may include a plurality of inspection units.

(2) In the above embodiment, the pH measuring unit 5 includes the sampling pump 51 and the sample tank 52, and is configured to measure the pH of the garbage treatment liquid DW sampled in the sample tank 52. However, without being limited to such a configuration, the inspection unit of the garbage disposal apparatus according to the present invention may be configured to be capable of directly inspecting the treated garbage liquid being fermented in the fermentation processing unit. .

(3) In the above embodiment, one of the pumps 3A and 3B is configured to be operable as an agitation pump and the other as a transfer pump, so the garbage disposal apparatus 100 is configured to include a transfer section and an agitation section. was described as an example. However, without being limited to such a configuration, the kitchen garbage disposal apparatus according to the present invention may not include the agitator.

(4) In the above embodiment, the example in which the pumps 3A and 3B are both operable as agitation pumps and transfer pumps has been described. However, without being limited to such a configuration, the food waste disposal apparatus according to the present invention may have the transfer section and the stirring section independently.

(5) In the above embodiment, an example of a configuration including the pumps 3A and 3B and the stirring flow path as the stirring section has been described. However, without being limited to such a configuration, the agitator of the food waste disposal apparatus according to the present invention can be provided as, for example, an agitator provided in the reservoir.

(6) In the above embodiment, the length of the operation period of each cycle of the pump 3B (transfer pump) that is intermittently operated based on the pH of the garbage treatment liquid DW measured by the pH measuring unit 5 has been described as an example. However, without being limited to such a configuration, in the garbage disposal apparatus according to the present invention, transfer of the garbage treatment liquid to the fermentation treatment section can be achieved by, for example, controlling the output of the transfer section, It can be controlled by controlling a distribution valve or the like.

Regarding other configurations, it should be understood that the embodiments disclosed in this specification are examples in all respects, and that the scope of the present invention is not limited by them. Those skilled in the art will easily understand that modifications can be made as appropriate without departing from the scope of the present invention. Therefore, other embodiments modified without departing from the gist of the present invention are naturally included in the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be used, for example, in a garbage processing apparatus that ferments garbage discharged from a food factory to generate biogas.

DESCRIPTION OF SYMBOLS 100: Garbage processing apparatus 1: Disposer unit 11: Hopper 12: Crusher 13: Liquid feed pump 14: Agitator 15: Screw feeder 2: Storage tank 21: Receptacle 22: Outlet 23: Return receptacle 3A: Pump 3B : Pump 31 to 34 : Piping 35, 36 : Valve 37 : Pump control unit 4 : Fermentation tank 41 : Receiving port 42 : Stirrer 43 : Sampling port 44 : Gas outlet 5 : pH measuring unit 51 : Sampling pump 52 : Sample tank 53: pH measuring instrument 54: Gate valve 6: Consumption facility W: Water D: Garbage DW: Garbage treatment liquid

Claims (6)

a crushing unit capable of crushing raw garbage;
a reservoir capable of storing a food waste treatment liquid containing the crushed food waste;
a stirring unit capable of stirring the garbage treatment liquid stored in the storage unit;
a transfer section capable of transferring the garbage treatment liquid stored in the storage section;
a fermentation processing unit that receives the garbage treatment liquid transferred by the transfer unit and is capable of fermenting the garbage treatment liquid;
an inspection unit capable of inspecting the garbage treatment liquid fermented in the fermentation processing unit ,
A pump as the stirring unit and the transfer unit,
an upstream side of the pump is in fluid communication with the reservoir and a downstream side of the pump is in fluid communication with the fermentation treatment section and the reservoir;
The inspection unit has a collection unit capable of collecting a portion of the treated food waste liquid fermented in the fermentation processing unit and stored in a sample tank different from the fermentation processing unit,
The inspection is performed on the garbage treatment liquid collected in the sample tank,
The transfer unit controls the transfer of the garbage treatment liquid to the fermentation processing unit based on the result of the inspection performed by the inspection unit. The inspection unit is capable of measuring the pH of the garbage treatment liquid,
2. The garbage disposal apparatus according to claim 1, wherein said transfer section controls transfer of said garbage treatment liquid to said fermentation treatment section based on the pH of said garbage treatment liquid. comprising at least two pumps;
an upstream side of each pump is in fluid communication with the reservoir;
2. The garbage disposal apparatus according to claim 1 , wherein the downstream side of each pump is in fluid communication with the fermentation section and the storage section. 4. The garbage disposal apparatus according to any one of claims 1 to 3, wherein operation of said pump is controlled based on the result of said inspection. The garbage disposal apparatus according to any one of claims 1 to 4 , wherein the fermentation treatment in the fermentation treatment section is performed at 50°C or higher. A crushing treatment process for crushing raw garbage;
a storage step of storing a garbage treatment liquid containing the crushed garbage in a reservoir ;
a stirring step of circulating the food waste treatment liquid stored in the storage part by means of a pump through a stirring channel to maintain a dispersed state of the food waste treatment liquid;
a transfer step of transferring the garbage treatment liquid stored in the storage unit to the fermentation processing unit by the pump ;
a fermentation treatment step of fermenting the garbage treatment liquid transferred to the fermentation treatment unit ;
an inspection step of storing a portion of the treated garbage liquid fermented in the fermentation processing unit in a sample tank different from the fermentation processing unit and performing an inspection;
The garbage disposal method, wherein, in the transfer step, the transfer of the garbage treatment liquid is controlled based on the result of the inspection.

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