JP2003137680A - Method of decreasing malodor in preparation of compost - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of inexpensively and easily decreasing the malodors produced in preparing compost which is applicable even to a motor driven garbage disposal machine for household use. SOLUTION: This method of decreasing the malodors produced in preparing the compost comprises adding autotrophic nitrifying bacteria to the material to be prepared as the compost, thereby decreasing the ammonia odors generated from the material to be prepared as the compost in preparing the compost from organic wastes.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for reducing the malodor generated when composting organic waste.

[0002]

2. Description of the Related Art The composting and utilization of food waste generated at home has attracted attention as a part of resource reuse and garbage disposal measures. However, the odor generated during the preparation of the compost has been a serious problem in electric household garbage disposal machines for household use, which have become very popular in recent years. In order to reduce this odor, there has been proposed a method of utilizing a catalyst and an electric heater or adding a deodorizing device using an adsorbent (for example, JP-A-5-221767). However, these devices not only increase the initial cost and running cost, but also have a problem that they cannot cope with the generation of odors exceeding the expected amount.

On the other hand, attention has been paid to the malodorous substances generated in the process of composting, and a biological deodorizing device for deodorizing the main substance, ammonia, by utilizing the nitrification reaction by microorganisms has also been studied and attempted to be put into practical use. There is. However, these methods are still difficult in terms of maintenance and initial cost in that they are applied to electric household garbage disposers for home use.

[0004]

In view of the above problems, it is an object of the present invention to provide a method for reducing the malodor generated during compost preparation, which can be applied to an electric household waste disposal machine and is inexpensive and simple. And

[0005]

The present invention reduces the ammonia odor generated from a compost preparation by adding autotrophic nitrifying bacteria to the compost preparation when composting an organic waste. Is a method of reducing malodor during compost preparation.

[0006] The above-mentioned organic wastes include, for example, food waste discharged from homes and businesses; animal and plant residues discharged from food processing plants; surplus sludge generated from wastewater treatment plants; livestock discharged from livestock farms. Manure; rice straw discharged by farmers; rice husks and other wastes mainly composed of biodegradable organic matter.

The above-mentioned compost means a composted organic waste. In addition, the compost preparation according to the present invention means an intermediate when the organic waste is processed into compost. That is, the entire mixture of organic waste and the resulting compost.

[0008] As an example of the above-mentioned composting, as a method of utilizing nature, oxygen is obtained by placing human dwelling bedding, rice straw, etc. on which night soil, kitchen drainage, etc. are dropped and piled up and down, and by occasionally transposing (cut back). A method of supplying easily, and decomposing easily decomposable organic matter with microorganisms in the natural environment can be mentioned. Also, artificially, after putting garbage into an artificial container, attach a stirring blade and a stirring motor, and automatically stir at regular intervals with a timer to easily decompose easily degradable organic matter by microorganisms under oxygen supply. Household electric garbage processing machines for disassembling are becoming popular.

The present invention includes Arthrobacter globiformis.
Not autotrophic nitrifying bacteria such as is) but autotrophic nitrifying bacteria are used. It is difficult to efficiently culture the above heterotrophic nitrifying bacteria. In contrast, autotrophic nitrifying bacteria are
Since it can be cultured by a relatively simple method, a large amount of bacteria can be obtained at low cost. Moreover, since no other nutrient source is required, nitrification reaction can be carried out rapidly with only ammonia as the nutritional value.

The above-mentioned autotrophic nitrifying bacteria are generally known as Nitrosomonas.
Genus, Nitrococcus genus, etc.
Commonly known bacteria that perform a nitrification reaction can be mentioned, and these can be used alone or in a mixed state.

As a method for culturing the above-mentioned autotrophic nitrifying bacteria, forest mulch and water are mixed and stirred to extract various bacteria, and then an inorganic ammonium salt such as ammonium carbonate is added as a nutrient source to perform liquid culture. Method: A method of performing liquid culture by adding an inorganic ammonium salt as a nutrient source to a treatment liquid in a nitrification tank of a wastewater treatment facility; a carrier for adhering nitrifying bacteria to the culture liquid is added, and the culture is continued to use the bacteria as a carrier. Examples of the method of attachment include the method. The type of the carrier is not particularly limited,
What is used in a treatment reaction by a known microorganism, a treatment tank or the like is used.

The culture amount is, for example, in the case of a household electric food waste processing machine for processing 1 kg of food waste per day, the nitrogen load is 1 g-N / day, preferably 5 g-N / da as nitrification capacity.
y or more is preferable. If the capacity is less than this, the effect of the present invention may not be obtained. In other cases, the nitrification capacity is adjusted according to the amount of treated organic waste per day, or the nitrogen load per day is measured, and the nitrification capacity is 20% or more of the load. It is preferable to culture until.

In the liquid culture method described in the above example, the amount of culture liquid is usually several L to several tens L. If this is put into the treatment tank as it is, the water content of the compost in the treatment tank increases significantly, and it becomes difficult to prepare the compost. Therefore 50
It is better to concentrate to about ml. Examples of the concentration method include methods generally used in the field of microbiology, such as collecting cells by a centrifuge.

The cultivated bacteria can be added to the compost preparation in the treatment tank in the form of a culture solution, the above-mentioned concentrate, a bacterium-adhering carrier in which the bacterium is cultivated and adhered to the carrier surface. The timing of adding the bacterium is not particularly limited, but is preferably, for example, the time when the compost preparation is started, the time when the ammonia odor starts to be generated from the compost being prepared, or the like.

When the above-mentioned autotrophic nitrifying bacteria are added to compost preparations, in addition to the above autotrophic nitrifying bacteria, bacteria that deodorize other malodorous substances such as mercaptans and bacteria that decompose and digest organic substances are also used. You may.

In the present invention, when the organic waste is newly added from the outside as the content of the above-mentioned compost preparation, the weight ratio of the already-produced compost to the weight of the new organic waste is 3: It is preferably 1 or more.
More preferably, it is 10: 1 or more. If the ratio is lower than 3: 1, the effect of reducing the ammonia odor may not be sufficiently exerted, or a large amount of mites and molds may be generated to make the compost preparation unsuccessful. The above weight ratio is a weight ratio in a wet state containing water.

During the preparation of compost, the temperature of the compost preparation is preferably maintained at 10 to 40 ° C. in order to maintain the activity of autotrophic nitrifying bacteria for a long period of time. More preferably, it is 20 to 30 ° C.

As a method for adjusting the temperature, when using a food waste treating device or the like, there is a method of attaching a heater or a cooling device, but simply, the weight of the compost and the organic material to be treated are added at the stage of designing the device. By setting the weight ratio of the waste to about 10: 1, it is possible to naturally maintain an appropriate temperature by the heat of fermentation by the microorganisms.

The pH value of the above compost preparation is preferably in the range of 6 to 9 in order to maintain the activity of autotrophic nitrifying bacteria for a long period of time. More preferably, it is 7.0 to 8.
The range is 5. Outside the above pH range, the activity of nitrifying bacteria is reduced and the ammonia suppressing effect is reduced. Examples of the method for adjusting the pH include means for adjusting the amount of organic waste input.

The place for carrying out the method of the present invention is not particularly limited, but it is preferably carried out in an artificial tank such as a commonly used fermenter.

Further, when preparing compost, it is preferable to use a water absorbing material that absorbs water in the organic waste in order to efficiently progress composting. Examples of such a water absorbing material include sawdust and water absorbing polymers.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION (Example) In a commercially available household electric garbage processing machine (tank capacity: 45 L), humus 3 as a microbial source was used.
0 L (about 15 kg) was packed, and 1 kg of commercially available dog food was added as organic waste per day to prepare compost. The ammonia gas concentration generated from this compost preparation was measured daily by the detector tube method. As a result, ammonia gas was generated from the 15th day. As a result of measuring the ammonia gas generation concentration, it was 2 ppm. Therefore, 50 ml of autotrophic nitrifying bacteria that had been cultured in advance was injected into the above compost preparation. Even after the addition of the above bacteria, 1 kg of dog food was added per day, which was continued for 30 days.
Then, the concentration of ammonia gas generated from the compost preparation was measured and found to be 4 ppm.

Comparative Example The same procedure as in the above Example was performed except that autotrophic nitrifying bacteria were not injected into the compost preparation at the time when ammonia gas was generated on the 15th day. As a result, the ammonia gas concentration was measured at the same final measurement time as in the example, and as a result, it was 50 ppm.

The autotrophic nitrifying bacteria used above were cultivated by the following procedure. After adding 25 L of tap water to commercially available mulch (30 L), the mixture was stirred and various fungi were extracted from the mulch. Aqueous ammonium carbonate solution was added to the extract to culture autotrophic nitrifying bacteria. For the culture, the nitric acid concentration of the culture solution was appropriately measured, and when the nitric acid concentration reached 4 g-N03 / L, the culture solution was exchanged by half. This was continued for about 8 months, and the final nitrification rate was 60 g-N03 / day. This culture solution was concentrated with a centrifuge to finally obtain 50 ml of a concentrated culture solution.

[0025]

EFFECTS OF THE INVENTION According to the method of the present invention, it is possible to reduce the generation of ammonia during the preparation of compost by a method of utilizing nitrifying bacteria, which is energy-saving, simple, and has a very low environmental load. This may solve the problem of reducing the offensive odor generated from the electric household garbage disposer for home use, and is considered to be useful for its widespread use.

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Claims (2)

[Claims] 1. When composting an organic waste,
A method for reducing malodor during compost preparation, which comprises reducing autonomic odor generated from the compost preparation by adding autotrophic nitrifying bacteria to the compost preparation. 2. The method for reducing malodor during compost preparation according to claim 1, wherein the pH value of the compost preparation is in the range of 6-9.