JP3590884B2 - Organic waste treatment system and treatment method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an organic waste treatment system and a treatment method for fermenting and decomposing organic waste such as garbage, food processing residues, and livestock manure using microorganisms.
[0002]
[Prior art]
Conventionally, organic wastes such as garbage, food processing residues, and livestock manure have been mostly treated by incineration or landfill. In recent years, due to the shortage of disposal sites, dioxin problems, etc., waste reduction and resource recycling have been progressing.Organic waste treatment equipment that uses the action of microorganisms, commonly called bio-type garbage disposal, It has begun to spread for business and business use.
[0003]
As bio-type garbage processing apparatuses, there are a type (composting type) in which a product after processing is reused as compost (compost) and an ultra-reduced type (extinction type) that hardly leaves any processed material. However, the compost made by the composting type is often not used effectively because its properties are unstable and it is not mature as compost. For this reason, there is an increasing need for the extinguishing-type waste disposal apparatus for business use.
[0004]
When organic matter such as garbage is treated in each of the above organic waste treatment apparatuses, most of the organic waste is decomposed into water and carbon dioxide gas. The carbon dioxide gas generated during the decomposition process is often discharged to the atmosphere without being treated. At present, measures against global warming are regarded as an urgent issue, and it is required to reduce or fix carbon dioxide, which is one of the causes of global warming.
[0005]
Further, ammonia and sulfur-based substances such as hydrogen sulfide and methyl mercaptan generated by fermentation and decomposition of organic wastes by microorganisms cause a problem as offensive odor, and are described in, for example, JP-A-6-271378. As described above, a processing apparatus in which odor countermeasures are taken by a deodorizing apparatus or the like has been developed. However, even with such a processing apparatus, the deodorization may be incomplete depending on the processed material and processing conditions.
[0006]
[Problems to be solved by the invention]
In an aerobic microorganism-type fermentation-decomposition type treatment device for organic waste, especially in an annihilation type (ultra-reduction type) treatment device that decomposes the treated material into water and carbon dioxide gas, all carbon elements in the treated material are carbon dioxide It is estimated that about 180 kg of carbon dioxide gas is generated per ton of standard garbage. Incidentally, 100% cereal garbage produces about 600 kg of carbon dioxide gas per ton. The annual emission of household and business garbage in Japan is said to be about 50 million tons (1996). Carbon dioxide gas is emitted. This is equivalent to 3% of the annual carbon dioxide emission in Japan (approximately 300 million tons), so there is concern about its impact on global warming.
[0007]
In addition, the revised Offensive Odor Control Law was enacted in 1996, and the odor index regulation system and the responsibilities of stakeholders for the prevention of odors were newly regulated. It has become to.
[0008]
An object of the present invention is to ferment and decompose organic waste by using microorganisms and to suppress the emission of carbon dioxide gas generated in the process to the atmosphere, and to further suppress odor components generated in the process to the outside. An object of the present invention is to provide an organic waste treatment system and a treatment method capable of suppressing discharge.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a feature of the present invention is that an organic waste including an organic waste such as garbage, food processing residue, and livestock manure is fermented and decomposed by microorganisms and has a treatment tank configured in an airtight structure. A waste treatment apparatus, a carbon dioxide fixing apparatus having a carbon dioxide fixing means for fixing carbon dioxide and having an airtight structure, and a carbon dioxide gas generated in the process of treating the organic waste. Means for supplying a gas in the organic waste treatment apparatus containing the gas to the carbon dioxide gas fixing apparatus, and a treatment tank of the organic waste treatment apparatus containing a gas containing air treated by the carbon dioxide gas fixing apparatus. And a means for fixing carbon dioxide gas. The carbon dioxide gas fixing means is a device for chemically fixing carbon dioxide gas.
[0010]
In the above, the carbon dioxide gas fixation device is provided with a fixation tank filled with a calcium hydroxide solution, and aeration provided at a lower portion of the fixation tank and discharging gas from the organic waste treatment device as fine bubbles. Preferably, a tube is provided.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
One embodiment of the present invention will be described with reference to FIGS.
The figure shows an organic waste treatment system provided with a biological carbon dioxide fixing device. In the figure, reference numeral 1 denotes an organic waste treatment device using microorganisms, and reference numeral 2 denotes a carbon dioxide generated in a process of the organic waste treatment device 1. It is a biological carbon dioxide fixing device for fixing gas.
[0017]
The organic waste treatment apparatus 1 includes a treatment tank (fermentation / decomposition tank) 3 for fermenting / decomposing organic waste, a charging door 4 for a treated substance (organic waste), and stirring for stirring the treated substance. It comprises a heater 5, a heater 6 for accelerating the processing, a thermistor 7 for detecting the temperature in the processing tank 3, and a temperature controller 8 for adjusting the temperature in the processing tank based on the temperature detected from the thermistor 7. Is done.
[0018]
The processing tank 3 is filled with a base material (or base material) 9 such as wood chips and sawdust as a moisture adjusting material for the processed product, and a seed bacterium containing a plurality of microorganisms involved in fermentation and decomposition. The base material 9 not only functions as a water conditioning material but also serves as a place where microorganisms live and grow. In addition, dominant microorganisms that perform fermentation / decomposition generally include aerobic and thermophilic Bacillus species that can work under aerobic conditions and at a temperature higher than the temperature range in which ordinary microorganisms grow. Microorganisms are used.
[0019]
The process of the fermentation / decomposition process will be described. First, organic waste, such as garbage, is thrown in from the throw-in door 4 of the processing apparatus 1. The shaft of the stirrer 5 in the processing apparatus is connected to the motor 5b by a chain belt 5a, and the processed material is mixed with the base material 9 by the stirrer. By the function of the stirrer 5, the water content of the processed product is adjusted so that the water content of the processed product is about 50 to 60%, which is easy for microorganisms to work, and air is supplied to the entire processed product by stirring to create an aerobic condition. . Further, at the same time as the stirring, the heater 6 provided around the processing tank 3, the thermistor 7 and the temperature controller 8 allow the inside of the tank to be around 60 ° C. (55-65 ° C.) which is said to be the optimum temperature of the microorganisms that perform fermentation and decomposition. ) And the fermentation / decomposition of microorganisms becomes active. Further, when harmful microorganisms having pathogenicity or the like inhabit in the processed product, the heat treatment can kill or inactivate the harmful microorganism.
[0020]
The reaction process of fermentation / decomposition by microorganisms differs depending on the components of the processed material, but organic substances such as carbohydrates and proteins in garbage are converted into glucose and amino acids by enzymes secreted from microorganisms, and are absorbed by microorganisms Or it is decomposed into carbon dioxide and water. However, in the process of decomposing amino acids, ammonia or sulfur-based substances may be generated, and these become odor components. An example of these reactions can be shown below.
(Carbohydrate) → _{(glucose): C 6 H 12 O 6} + 6O 2 → 6CO 2 + 6H 2 O
(Protein) → (amino acid): CxHyNzOp + aO ₂ → CuHvNwOq + bCO ₂ + dH ₂ O + eNH ₃
After this treatment, organic substances that are hardly decomposed and inorganic substances that remain after the decomposition can be used as compost (compost). In addition, since microorganisms involved in fermentation / decomposition live in the above organic and inorganic substances, they may be used as inoculum.
[0021]
As described above, composting-type processing equipment is a type that reuses the residue after processing as compost, and an extinguishing-type processing apparatus that performs fermentation / decomposition processing until almost no residue (compost) remains after processing. It is. Both types are the same in that stirring and heating operations are performed in the process. The water generated by the fermentation / decomposition process is drained to the outside through the drain pipe 11.
[0022]
Next, the biological carbon dioxide fixing device 2 will be described. The gas containing carbon dioxide gas generated in the organic waste treatment apparatus 1 is supplied to the culture tank 14 of the immobilization apparatus 2 via supply means such as an air pump 12 and an air supply pipe 13. The material of the culture tank 14 is made of a material having optical transparency such as transparent acrylic or glass. In the culture tank 14, a photosynthetic microorganism (green sulfur bacteria, helobacteria, etc.) capable of fixing carbon dioxide gas is present, or immobilized organisms such as algae (chlorella, spirulina, etc.) are inhabited. In the present embodiment, the immobilized organism 15 is cultured in a culture medium 14 in a liquid medium (culture liquid) 16 containing a nutrient for promoting growth. An aeration tube 17 is provided at the end of the air supply tube 13 led into the culture tank 14, and the culture solution in the culture tank is circulated and agitated by discharging fine bubbles from the aeration tube, thereby causing carbon dioxide gas to be added to the culture solution. It can be dissolved in water. The immobilized organism in the culture tank performs photosynthesis using the carbon dioxide gas. This immobilization reaction is typically represented by the following formula, and oxygen is produced simultaneously with the production of organic substances.
6CO ₂ + 6H ₂ O → C ₆ H ₁₂ O ₆ + 6O ₂
An exhaust pipe 18 is provided in the upper part of the culture tank 14, and a gas containing oxygen generated by the immobilization process and carbon dioxide gas that could not be completely dissolved in the medium is exhausted to the outside through the exhaust pipe 18.
[0023]
The discharge and supply of the culture solution and the immobilized organism 15 in the culture tank 14 are performed by opening and closing the valves 19a and 20a through a drain pipe 19 or a supply pipe 20 connected to the lower and upper parts of the culture tank, respectively. It is. The immobilized organisms recovered from the drainage pipe 19 can be used as feed or useful substances produced by the immobilized organisms (for example, antibacterial substances, ultraviolet absorbing substances, unsaturated fatty acids, produced when microalgae are used). And polysaccharides).
[0024]
Furthermore, in the culture tank 14, odor components such as ammonia and sulfur-based substances generated during the fermentation / decomposition process are brought into gas-liquid contact with a culture solution (liquid medium) in the culture tank, and the odor components such as photosynthetic microorganisms and algae It can be removed by absorption by immobilized organisms, and therefore a large deodorizing effect can be obtained.
[0025]
FIG. 3 is a diagram showing a processing flow of the organic waste in the embodiment of the present invention.
In the present embodiment, organic waste such as garbage, food processing residues, livestock manure, and the like are put into the treatment tank of the organic waste treatment apparatus 1 having an airtight structure. In the treatment tank, the treated material (waste) is stirred together with the base material and the inoculum, and the water content is adjusted so that the moisture content of the treated material is about 50 to 60%, which is easy for microorganisms to work on. Air is supplied throughout the object to create aerobic conditions. Furthermore, the inside of the tank is uniformly adjusted to around 60 ° C., which is said to be the optimum temperature of the microorganisms to be fermented and decomposed, by a heater or the like provided around the treatment tank at the same time as stirring, so that the fermentation and decomposition of the microorganisms become active. To After this treatment, organic substances that are hardly decomposed and inorganic substances that remain after the decomposition can also be used as compost (compost). In this embodiment, the destruction type processing apparatus performs the fermentation / decomposition processing until almost no residue (compost) remains after the processing. Since a large amount of carbon dioxide gas is generated in the process, the gas containing the carbon dioxide gas has an airtight structure. Is supplied to the culture tank 14 of the carbon dioxide immobilization apparatus. In the culture tank, the culture solution is circulated and stirred to dissolve carbon dioxide in the culture solution, and immobilized organisms such as photosynthetic microorganisms and algae in the culture tank perform photosynthesis using the carbon dioxide gas, Immobilize the gas. In the culture tank, odor components such as ammonia and sulfur-based substances generated during the fermentation / decomposition process are also in gas-liquid contact with the culture solution (liquid medium) in the culture tank, and immobilized organisms such as photosynthetic microorganisms and algae. Can be removed by absorption. The gas from which the odor component has been removed in this way is discharged outside the fixing device (outside air or the like) as exhaust gas.
[0026]
It should be noted that the exhaust gas from which the odor component has been removed (the gas including the air processed by the carbon dioxide fixing device) may not be discharged to the outside air, but may be returned to the processing tank for processing the organic waste. With such a configuration, it is possible to almost completely suppress leakage of the odor component into the outside air.
[0027]
Although the biological immobilization device is used in the above embodiment, a chemical carbon dioxide immobilization device for immobilizing carbon dioxide gas by converting carbon dioxide gas into calcium carbonate may be used. That is, the gas containing carbon dioxide gas generated in the organic waste treatment apparatus is supplied to the immobilization tank (corresponding to the culture tank 14) of the immobilization apparatus 2 via the air supply pipe 13 by the air pump 12. The fixation tank is filled with a calcium hydroxide solution, and an aeration pipe 17 is provided at the tip of an air supply pipe led to the lower part of the fixation tank, and fine bubbles are discharged from the aeration pipe. By doing so, the carbon dioxide gas can be fixed by dissolving it in the calcium hydroxide solution in the fixing tank and causing a chemical reaction. The reaction of carbon dioxide fixation can be represented by the following equation.
Ca (OH) ₂ + CO ₂ → CaCO ₃ + H ₂ O
Also in the case of a chemical carbon dioxide fixing device, similarly to FIG. 1, an exhaust pipe 18 is connected to the upper part of the fixing tank, and the gas from which the carbon dioxide has been removed by the fixing process is passed through the exhaust pipe to the outside. Exhaust. Further, the supply of the calcium hydroxide solution and the discharge of calcium carbonate in the immobilization tank can be performed through a liquid supply pipe 20 and a drain pipe 19 connected to the upper and lower parts of the culture tank, respectively.
[0028]
Another embodiment of the present invention will be described with reference to FIGS. In this embodiment, a passage (exhaust pipe) 18 is provided for returning the air treated in the carbon dioxide fixing device to the treatment tank 3 in which the fermentation / decomposition treatment is performed, and the odor generated in the treatment process is discharged to the outside. It is intended to be trapped in the processing system without being released.
[0029]
Also in this embodiment, a biological carbon dioxide fixing device is used for fixing carbon dioxide. The system configuration includes an organic waste treatment apparatus 1 using microorganisms, a biological carbon dioxide fixation apparatus 2 for fixing carbon dioxide generated in a treatment process, and a treatment tank for performing fermentation and decomposition processing in the organic waste treatment apparatus 1. 3 and a culture tank 14 of the biological carbon dioxide fixing device 2 are constituted by an air supply pipe 13 and an exhaust pipe 18 and the like.
[0030]
The configurations of the organic waste treatment apparatus and the biological carbon dioxide fixing apparatus are the same as those in the above-described embodiment, but the fixing apparatus has an airtight structure, and the carbon dioxide fixing processing and the odor component in the culture tank. The gas from which is removed is not exhausted to the outside, but is returned to the treatment tank 3 in the organic waste treatment apparatus 1 through the exhaust pipe 18 again. Furthermore, the treatment tank for fermentation / decomposition also has an airtight structure, so that gas is circulated in the fermentation / decomposition treatment process of organic waste and the fixation treatment process of carbon dioxide gas, so that it could not be removed by immobilization treatment. The fixation of carbon dioxide gas can be made more complete, and the emission of odor to the outside can be suppressed.
[0031]
【The invention's effect】
According to the present invention, the carbon dioxide gas generated in the fermentation / decomposition process by the organic waste treatment device is fixed by the fixing device, so that the amount of carbon dioxide gas emitted to the atmosphere can be reduced. In addition, since deodorization is performed simultaneously with the immobilization process, there is an effect that air containing odor generated in the process can be prevented from being discharged to the outside.
[0032]
Further, according to the present invention, which includes means for returning the gas containing air treated by the carbon dioxide fixing device to the treatment tank of the organic waste treatment device, the gas containing odor generated during the fermentation / decomposition treatment process is included. The gas is not released to the outside, so that not only the odor leakage can be more completely suppressed, but also the carbon dioxide gas can be more completely fixed.
[Brief description of the drawings]
FIG. 1 is a sectional view showing one embodiment of an organic waste treatment system of the present invention.
FIG. 2 is a perspective view of FIG.
FIG. 3 is a diagram showing an example of a processing flow in the organic waste processing of the present invention.
FIG. 4 is a sectional view showing another embodiment of the organic waste treatment system of the present invention.
FIG. 5 is a perspective view of FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Organic waste treatment apparatus, 2 ... Carbon dioxide fixation apparatus, 3 ... Processing tank (fermentation / decomposition tank), 4 ... Input door, 5 ... Stirrer, 5a ... Chain belt, 5b ... Motor, 6 ... Heating Heater, 7: Thermistor, 8: Temperature controller, 9: Base material (base material), 11: Drain pipe, 12, 13: Supply means (12: Air pump, 13: Air supply pipe), 14: Culture tank (fixed) Tank), 15: immobilized organism, 16: liquid medium (culture solution), 17: aeration pipe, 18: exhaust pipe (means for returning to the processing tank), 19: drain pipe, 19a: drain pipe valve, 20 ... Supply pipe, 20a ... Supply pipe valve.

Claims (2)

Organic waste treatment equipment that performs fermentation and decomposition treatment of organic waste such as garbage, food processing residue, livestock manure, etc. by microorganisms and has a treatment tank configured in an airtight structure, and to fix carbon dioxide gas A carbon dioxide gas fixing device having a carbon dioxide gas fixing means and having an airtight structure, and a gas in the organic waste treatment device containing carbon dioxide gas generated in the process of treating the organic waste, is treated with the carbon dioxide gas. and means for supplying the gas immobilization device, and means for a gas containing air which has been treated with the carbon dioxide fixing apparatus back into the treatment tank of the organic waste treatment apparatus, wherein the carbon dioxide fixing The organic waste treatment system is characterized in that the conversion means is a device for chemically fixing carbon dioxide gas . 2. The carbon dioxide gas fixing device according to claim 1 , wherein the carbon dioxide gas fixing device is provided with a fixing bath filled with a calcium hydroxide solution, and a gas is discharged from the organic waste treatment device as fine bubbles provided in a lower portion of the fixing bath. An organic waste treatment system, comprising:

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