JP2009285554A - Solid food organic waste treating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To greatly reduce volume of solid organic waste produced in a food processing factory. <P>SOLUTION: A solid food organic waste treating method includes a cutting process S11 for cutting solid waste such as a stalk of broccoli produced in the food processing factory to obtain minute waste pieces of 3 to 5 mm size, a grinding process S12 for grinding the waste pieces to obtain paste of 150 μm size and a heating process S13 for heating the waste paste to a sol state. Sewage of the sol state after heating is subjected to oxidative decomposition by ozone at an ozone treatment process S21 and then to biological decomposition by aeration at an activated sludge treatment process S22. Sludge subjected to biological decomposition becomes sludge cake through an dehydration process S23. The sludge cake can be utilized as compost. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for treating solid food organic waste, and more particularly to treatment of food (including food) to be discarded in a food processing factory, typically vegetables, fruit agricultural products, and processed products thereof.

  Convenience stores, department stores, supermarkets, etc. sell cooked foods such as lunch boxes and prepared dishes, but the market size tends to increase year by year. At food processing factories that provide food to these stores, processing of waste generated in the food processing process, such as vegetable and fruit residues (typically processing of raw vegetable scraps and apple peels) is a problem. Therefore, volume reduction of this kind of waste is a big issue.

  Patent Document 1 discloses a technique for solubilizing organic waste such as garbage, food waste, and livestock manure. In the method for solubilizing organic waste described in Patent Document 1, as shown in FIG. 4 attached hereto, the organic waste is put into the compression crusher and then the organic waste is applied by instantaneously applying high pressure. The waste material is compressed, and the waste material is crushed into fine particles through the discharge hole and fed into the solubilization tank through the pressure tube.

  In the solubilization tank, the fine particulate organic waste in the solubilization tank is maintained by stirring while maintaining the pressure state and heating to 30 to 70 ° C. for 4 to 8 hours. Solubilized waste is solubilized by the synergistic effect of pressure and temperature, and the solubilized waste is fed into the fermentor through a transfer tube. In the fermenter, anaerobic fermentation and aerobic fermentation are performed. According to Table 1 of patent document 1, although it changes with the pressure and temperature of a solubilization tank, the solubilization rate of garbage is described as 75 to 90%.

JP-A-11-221551

  Patent Document 1 described above is intended for a wide range of organic waste such as manure, sewage sludge, agricultural sludge, raw garbage, and food waste. The inventors of the present application have specialized in solid food organic waste generated in food processing factories, and have devised the present invention as a result of studying effective treatment of fruit and raw vegetable residues, for example. is there.

  The objective of this invention is providing the solid food organic waste processing method which can implement | achieve the significant volume reduction of the solid waste generated in a food processing factory.

According to the present invention, the above technical problem is
A cutting process for cutting solid food organic waste,
A grinding step of grinding the waste pieces that have become finer by the cutting step to produce a waste paste;
A heating step of heating the waste paste generated by the grinding step to a waste component-containing liquid in a sol state;
An ozone treatment step of oxidizing and decomposing the waste component-containing liquid in the sol state with ozone;
An activated sludge treatment step for microbially degrading the sewage through the ozone treatment step;
It is achieved by providing a solid food organic waste treatment method characterized by comprising a dehydration step of dewatering sludge from the activated sludge treatment step to produce a sludge cake.

  In the solid food organic waste processing method of the present invention, it is possible to damage the cell wall of the solid waste by grinding the waste pieces that have been cut into fine pieces such as vegetable waste and fruit waste into a waste paste. In the subsequent heating step, the components contained in the waste are eluted to form a waste component-containing liquid in a sol state, and at the same time, the waste components are not separated from the waste water by softening the fiber structure of the solid waste. Since the state is generated, the oxidative decomposition of the waste component-containing liquid and the subsequent microbial decomposition in the subsequent ozone treatment process can be promoted, and thereby the volume of solid food organic waste can be greatly reduced. .

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

  FIG. 1 is a flowchart showing an outline of the solid food organic waste treatment method of the embodiment. Solid food organic waste generated in a food processing factory is processed according to the flow shown in FIG. The following are typical examples of waste generated at food processing plants.

(1) Raw vegetable scraps, such as lettuce core, lettuce outer leaves, cabbage core, cabbage outer leaves, carrot peel, carrot peel, radish peel, radish peel, broccoli stem;
(2) Fruit scraps such as apple and pear skin, watermelon skin, melon skin, citrus thin skin and fruit skin such as mandarin orange, banana skin, strawberry peel, mango skin;
(3) damaged vegetables and fruits.

  Solid food organic waste treatment can be divided into pre-treatment and post-treatment. The pre-treatment includes cutting step S11 to cut broccoli stems and the like into small waste pieces of 3 to 5 mm, and grinding the fine waste pieces from the cutting step S11 to 150 μm. It includes a grinding step S12 for making a paste, and a heating step S13 for heat sterilization until the waste paste from the grinding step S12 reaches a high temperature (for example, 100 ° C.).

  Next post-treatment is ozone treatment step S21 that oxidizes and decomposes with ozone, activated sludge treatment step S22 that microbially decomposes oxidatively decomposed sewage, and dewatered sludge from activated sludge treatment step S22 to make a sludge cake And step S23.

  As a result of a trial run with vegetable scraps and fruit scraps, it was found that there was "residue" in which sewage was mixed with vegetables and fruit residue, and "no residue" in which sewage was not mixed with vegetables and fruit residue. There is no change in the amount of sludge cake generated after the dehydration step S23. Therefore, it can be said that the volume reduction of the vegetable and fruit residue has been substantially reduced by 100%.

  The post-treatment process described above can also be used for the treatment of oil-containing wastewater containing edible oil. In other words, by adding the above pretreatment step before the series of steps of ozone treatment step S21, activated sludge treatment step S22, dehydration step S23 installed for treatment of sewage containing edible oil, Waste treatment can be performed while diverting the treatment facility, and the volume of solid food organic waste can be greatly reduced.

  FIG. 2 shows an outline of a facility constituting a pretreatment process in the treatment of solid food organic waste. The cutting process S11 is performed by the cutting machine 10 on the solid organic waste containing the residues of vegetables and fruits. The cutting machine 10 has a rotating cutting blade, accepts solid organic waste conveyed by a conveyor, and cuts it into small pieces of 3 to 5 mm by the cutting blade. The fine waste pieces coming out of the cutting machine 10 are put into the next attritor 12, making it easier to elute the components contained in the solid organic waste in the subsequent heating step, and further promoting the subsequent microbial degradation. For this reason, the waste pieces are ground to a paste state by, for example, 150 μm or less with a grinder 12 that damages the cell walls of the waste. When water is insufficient in the processing of the grinder 12, it is better to grind while supplying some water to the grinder 12.

  The waste paste discharged from the grinder 12 is pumped to the steam continuous heating device 16 by a monopump (not shown) and a transfer pipe 14. The steam-type continuous heating device 16 has a plurality of heat transfer pipes 16b inside the outer cylinder 16a, and steam is continuously supplied to the outer cylinder 16a. Waste paste supplied under pressure from the transfer pipe 14 is heated to, for example, 100 ° C. in the process of passing through the heat transfer pipe 16b. By heating at 100 ° C., the waste paste becomes a sol-state waste component-containing solution in which solid components are difficult to separate due to elution of components contained in solid organic waste, such as pectin, and inhibits subsequent microbial degradation It is possible to soften the fiber structure of organic food waste while eliminating various germs, and by this heat treatment, it is possible to prevent the precipitation and decay of waste components in each treatment tank later, and oxidative degradation and microorganisms Degradation can be accelerated.

  The heating of the waste paste by the heating device 16 may be at or above the temperature at which the components are eluted from the waste paste so that the waste component-containing liquid is in a sol state. If it is 85 degreeC or more, Preferably it is 90 degreeC or more, Most preferably, it is 98 degreeC or more, and it can be set as the sol state where a solid-liquid is hard to isolate | separate. The upper limit of the temperature of the waste paste can be heated locally up to about 150 ° C if the steam used is high-pressure steam, but back pressure is required and the equipment cost becomes expensive. Therefore, it is preferable to heat to the boiling point of the waste paste, which is generally about 100 ° C.

  The waste component-containing liquid in a sol state after passing through the steam-type continuous heating device 16 and sterilized by heating at about 100 ° C. is supplied to the ozone treatment tank 20. The ozone treatment tank 20 constitutes a part of the post-treatment process, and the post-treatment process is roughly composed of a sewage treatment tank 22, a regulation tank 24, an aeration tank 26, a precipitation tank 28, and a dehydrator 30. ing.

  The ozone treatment tank 20 receives wastewater in the food processing factory in addition to the waste component-containing liquid. Here, the wastewater may include paste-like or puree-like wastes such as tomato puree, raspberry puree, and chestnut paste, which are to be discarded. The paste-like or puree-like waste that is to be discarded may be put into the above-described grinder 12 or may be put into the heating device 16.

  In the ozone treatment tank 20, compressed air containing ozone generated by an ozone generator is diffused. The sewage containing the waste component-containing liquid in the ozone treatment tank 20 is aerated with ozone, so that the sewage is oxidatively decomposed and pumped up by a pump and supplied to the screen 34 through the first pipe 32. And sent to the sewage treatment tank 22.

  The wastewater treatment tank 22 is also supplied with wastewater containing fats and oils. In the sewage treatment tank 22, compressed air containing ozone generated by an ozone generator is diffused. By performing aeration with ozone in the sewage treatment tank 22, the oxidative decomposition of the fat and oil component mixed in the sewage and the second oxidative decomposition of the waste component-containing liquid are performed. When limited to sewage treatment including fats and oils, the sewage treatment tank 22 can be called an oil and fat decomposition tank. The sewage in the sewage treatment tank 22 is changed from the oil sticky state to the fluidity state by ozone aeration, and the odor is greatly reduced.

  The sewage in the sewage treatment tank 22 is sent to the adjustment tank 24 through the second pipe 36. In the adjustment tank 24, compressed air containing ozone is preferably diffused, and the third oxidative decomposition with ozone is also performed in the adjustment tank 24.

  The sewage in the adjustment tank 24 is pumped up by a pump and sent to the aeration tank 26 through the third pipe 38. In the aeration tank 26, aeration with compressed air is performed, and in the aeration tank 26, organic substances in the sewage are decomposed by aerobic microorganisms into carbon dioxide gas and water. The sewage in the aeration tank 26 is sent to the settling tank 28 through the fourth pipe 40, and the sludge separated in the settling tank 28 is sent to the dehydrator 30 through the fifth pipe 42. On the other hand, the supernatant liquid of the settling tank 28 is taken out from the settling tank 28 and then sterilized and sterilized by chlorine disinfection and then discharged into sewage.

  Here, a multiple disk dehydrator is employed as the dehydrator 30. In this multi-disk type dehydrator, the pitch between adjacent disks is narrowed in the sludge movement direction, so that dewatering is performed while the sludge is compressed in the process of passing through the dehydrator 30, and the sludge cake is removed from the dehydrator 30. Is discharged. And this sludge cake can be utilized as compost. In addition, the multi-disk dehydrator has a characteristic that it can be relatively easily handled by fine adjustment when the dewatering efficiency changes due to the physical properties of the sludge to be treated. In this case, the dewatering efficiency does not decrease as compared with a belt press or screw press type dehydrator. When tested on the residue of vegetables and fruits, it was confirmed that the sludge physical properties matched the characteristics of the multi-disk dehydrator, and good dewatering efficiency could be realized.

  According to the above-described embodiment, for example, the sewage treatment tank 22, the adjustment tank 24, the aeration tank 26, the precipitation tank 28, and the dehydrator 30 for treating the edible oil-containing wastewater discharged from the fryer are used to process food. This includes the advantage of reducing the volume of solid organic waste generated in the factory.

  In addition, it is possible to substantially reduce the volume of vegetable and fruit residues experimentally implemented as described above, and is a treatment that utilizes oxidative degradation and microbial degradation by ozone, and uses chemicals. The quality of treated water is not deteriorated. Furthermore, since the generated residue of vegetables and fruits can be processed immediately and continuously, there is an advantage that a space for storing the residues of vegetables and fruits in the factory is not required, and that the space is saved and hygienic. .

  In addition, the embodiment has an advantage that waste generated in a food processing factory including fat and oil waste, paste-like and puree-like waste can be comprehensively treated.

It is a figure which shows the whole flow of the solid food organic waste processing method of an Example. It is a figure which shows the outline | summary of the structure which comprises the pre-processing process included in the solid food organic waste processing method of an Example. It is a figure which shows the outline | summary of the facility which comprises the post-processing process included in the solid food organic waste processing method of an Example. It is a flowchart for demonstrating the outline | summary of a prior art example.

Explanation of symbols

S11 Cutting process
S12 grinding process
S13 Heating process
S21 Ozone treatment process
S22 Activated sludge treatment process
S23 Dehydration process 10 Cutting machine 12 Grinding machine 16 Steam type continuous heating device 20 Ozone treatment tank 22 Sewage treatment tank 24 Adjustment tank 26 Aeration tank 28 Precipitation tank 30 Dehydrator

Claims (6)

A cutting process for cutting solid food organic waste,
A grinding step of grinding the waste pieces that have become finer by the cutting step to produce a waste paste;
A heating step of heating the waste paste generated by the grinding step to a waste component-containing liquid in a sol state;
An ozone treatment step of oxidizing and decomposing the waste component-containing liquid in the sol state with ozone;
An activated sludge treatment step for microbially degrading the sewage through the ozone treatment step;
A solid food organic waste treatment method comprising: a dehydration step of dewatering the sludge produced from the activated sludge treatment step to produce a sludge cake.   The solid food organic waste treatment method according to claim 1, wherein aeration with air is performed in the activated sludge treatment step.   The solid food organic waste processing method according to claim 2, wherein the dehydration step is performed by a multi-disc dehydrator.   The solid food organic waste processing method according to claim 2 or 3, wherein the ozone treatment step is performed in multiple stages.   The solid food organic waste treatment method according to claim 1, wherein fat and oil-containing wastewater can be input into the ozone treatment process, and the oil and fat component is oxidatively decomposed in the ozone treatment process.   The solid food organic waste processing method according to claim 1, wherein paste-like or puree-like food waste can be input to the ozone treatment step.

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