JPH0430866B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a deodorizing method using microorganisms, and particularly to a deodorizing method using microorganisms for removing bad odors that are a source of pollution at low cost. Conventional technology Complaints about bad odors are increasing with the progress of urbanization, and according to the 1988 White Paper on Pollution issued by the Environment Agency, about a quarter of complaints about pollution are related to bad odors, making it the second largest problem after noise. It is the th. Sources of bad odors include livestock excrement, industrial waste, raw materials in manufacturing plants, intermediate and final products, by-products, household waste, sewage treatment equipment, garbage incineration equipment, etc. The method of covering with soil, which has been used for a long time as a countermeasure against bad odors, is not necessarily efficient and requires a large area of equipment, so it is not practical. Conventional general countermeasures include incineration, adsorption, chemical decomposition, washing and solubilization, etc., but all of them require large amounts of consumables such as fuel and chemicals and large equipment, making them technically and economically difficult. It was not something that I should be satisfied with. The so-called biofreshure method is known as a biological deodorization method that utilizes surplus sludge from water treatment equipment, which was previously disposed of, as a deodorizer. In this method, surplus sludge made into a slurry is sprayed as a deodorizer, and this is brought into countercurrent contact with a gas containing malodorous components to deodorize.This method has the advantages of reducing the cost of the deodorizer and saving equipment space by using a scrubber tower. have However, the so-called biofreshure method requires large equipment costs, operating costs, and maintenance costs because the slurry is constantly circulated. Problems to be solved by the invention Therefore, the problems to be solved by the invention are as follows:
Cost reduction in biological deodorization methods. Means for solving the problems In the deodorizing method using microorganisms of the present invention,
Deodorizing microorganisms are fixed on ^100cm3 of sphagnum peat with an air-dry weight of 11g or less, and the moisture content of this porous deodorizing layer made of sphagnum peat and 0.1% or more pore-filling material is kept at 50% or more. Deodorization is performed by passing a certain gas through. An example of a pore-forming material is a so-called "eyeball" made of activated carbon or a material such as plastic or glass formed into a porous spherical shape or the like. The present inventor focused on the efficiency of deodorizing methods that utilize microorganisms contained in sludge and soil, and as a result of repeated research experiments on increasing the air permeability and contact area of microorganism carriers, the inventor found that peat is an appropriate carrier for microorganisms. I found that. Peat is generally produced by plants such as trees, herbs, algae, and moss that grow in swamps, lakes, or nearby moist areas. At some stage during the process of decomposition by microorganisms, decomposition stagnates in anaerobic conditions lacking oxygen. This is what was deposited. A pile of peat is sometimes called peat soil. In Japan, peat has long been classified as low peat, intermediate peat, and high peat, and the main constituent plant species have also been clarified. The total amount of peat resources worldwide is estimated to be approximately 2.8 billion tons, of which the share of each country's resources is 60.7% in the Soviet Union, 8.2% in Finland, 8.2% in Finland,
It is said that Canada accounts for 7.8%, and Japan accounts for 0.18%, and the amount of resources is said to be about 900 million tons. Peat in Japan is mainly distributed in Hokkaido and the Tohoku region.
Table 1 shows the volumetric weight, water capacity, water holding capacity, and other properties of peat in comparison with those of loam soil.

【table】

[Table] The volumetric weight of the other three types of peat is significantly lower than that of the planted loam, and the ranking is sphagnum peat < sedge peat <
It is reed peat, and sphagnum peat is 11g/100cm ³
This is an extremely low value. This indicates that peat, especially sphagnum peat, retains much of its remains and has many pores distributed within its structure. Looking at the water capacity, the planted soil is 44.3%, while other peat is distributed in the range of 289-1057%.
The values are particularly high in sphagnum peat. Peat thus has many distributed pores,
It has an extremely small volumetric weight and a large amount of water retention.
Moreover, the effectiveness of retained moisture is almost the same as that of planting soil. These properties are particularly remarkable in the case of sphagnum peat, which has low degradability and is fibrous, indicating that peat, especially sphagnum peat, is an excellent material as a carrier for immobilizing microorganisms. That is, when the gas to be treated is passed through a microbial deodorizing layer using peat as a carrier, it is expected that the pressure loss will be small and the power consumption required for air blowing will be small. As a result of comparing the relationship between water content and pressure loss in fibrous peat carbon with that of other carriers, it was confirmed that peat layers exhibit significantly lower pressure loss values over a wide range of water content. In practical deodorizing equipment that requires long-term operation, moisture content is a very important factor, so low pressure loss over a wide range of moisture content is a particularly desirable property for carriers. The reason why wet peat containing water is used in the present invention is that dry peat has little deodorizing effect. It is well known that dissolving malodorous substances in water has a deodorizing effect. Examples of microorganisms for decomposing malodorous substances used in the present invention include microorganisms collected from pig pens, cow pens, poultry pens, or soil in their vicinity, microorganisms collected from activated peat in various water treatment facilities, and anaerobic sludge. These are things taken from. Generally, malodorous substances are often complex systems rather than single compounds, and it is preferable that the microorganisms that have decomposition ability be a mixed system consisting of several types of microorganisms rather than a single type. A method for collecting microorganisms is to embed an immobilized carrier made of peat in the soil near the facility where the malodorous substance is generated for a certain period of time, and allow microorganisms that have activity against the malodorous substance to migrate to the immobilized carrier and become accustomed to it. is convenient. Odorless microorganisms include mold, yeast,
Although they can be classified into actinomycetes and bacteria, it is not always easy to identify preferred microorganisms because there are a wide variety of malodorous substances. The reality is that finding microorganisms that are effective against bad odors to be removed requires trial and error experiments. Effective deodorizing microorganisms have been successfully isolated and identified for some specific malodorous substances, and highly efficient deodorizing technology based on mass cultivation has also been developed. However, it is difficult to say that general microbial deodorization technology has been established yet. Effects To explain the effects, as pointed out earlier, the pressure drop when gas is passed through a hydrated peat layer is extremely low over a wide range of moisture content. By passing odorous air through peat, the odor can be removed without requiring particularly large blowing power. Therefore, equipment for circulating slurry-like sludge and power for circulation are not required, and the blowing power is small, so that cost reduction in the biological deodorization method, which is the objective of the present invention, can be achieved reliably. . EXAMPLES The present invention will be described in further detail below with reference to Examples. In the present invention, a suitable pore-forming material is used to maintain constant gas flow in the peat. Examples of pore-forming materials include activated carbon and spherical porous bodies.
Activated carbon not only has high surface activity and physical adsorption ability, but also has excellent properties as a microbial carrier. In other words, when mixed into soil as agricultural carbon, it improves aggregate structure, water retention, air permeability, fertilizer retention,
It has been recognized that it exhibits excellent properties for improving the microbial environment in terms of soil temperature rise, microbial growth, pH adjustment, etc. The present inventor has experimentally found that a microbial immobilization carrier prepared by mixing 30-0.1% activated carbon with peat is preferable. A spherical porous body is one made of plastic, glass, or other material molded into a porous spherical shape.
One example is the porous material manufactured and sold by Tokyo Tokushu Wire Mesh Co., Ltd. under the name "Eyeball", which has a diameter of 25 mm.
mm, surface area 314m ² /m ³ , free volume 92%, density 84000
It is commercially available as products with particles/m ³ and other particle sizes and characteristics. Example 1 Activated sludge liquid collected at Kitatama Sewage Treatment Plant in Tokyo
75ml was impregnated with 240g of sphagnum peat from the Soviet Union.
The properties of the Soviet sphagnum peat were as follows. Moisture 52.41%, total nitrogen 1.03%, total phosphoric acid 0.13%, total potassium 0.04%, crude ash 2.71%, loss on ignition 97.29%, organic carbon 50.03%, carbon percentage 48.6%, crude humic acid 12.2%, cation exchange capacity A 1.15 meq/100 g column with an internal diameter of 60 mm and a height of 500 mm was filled with 50% of the above sludge-impregnated peat and 50% of the above spherical porous eyeballs with a diameter of 25 mm in an internal volume of 1350 ml. From the top of the column, 50-100ppm
Air containing hydrogen sulfide was blown in at a rate of 100 ml per hour, and continuous operation was carried out for about 24 days. To prevent the peat from drying out, water was sprayed from the top from time to time to adjust the moisture content of the peat to 50-80%. The deodorizing efficiency was calculated by measuring the hydrogen sulfide concentration at the inlet and outlet of the column using a detection tube.
The deodorizing efficiency during the above operation period was 100%. Example 2 An experiment was conducted in the same manner as in Example 1, except that anaerobic sludge collected from a methane fermentation reactor was used instead of the activated sludge collected at the Kitatama Sewage Treatment Plant. The deodorizing efficiency during this experimental period was also 100%. Example 3 Same as Example 1 except that instead of the impregnation treatment with the activated sludge liquid collected at the Kitatama Sewage Treatment Plant, 250 g of soil collected from the Morimoto Pig Farm in Kisarazu City, Chiba Prefecture was mixed and treated. The experiment was conducted using a method. The deodorizing efficiency during this experimental period was also 100%. Example 4 The peat produced in the Soviet Union was left buried in the soil of the pig farm in Example 3, and microorganisms were collected. Inner diameter 60mm, height
A 500 mm column was filled with a mixture of 350 g of the microorganism-collected sphagnum peat and 60 spherical porous eyeballs each having a diameter of 25 mm. Air containing 100-150 ppm hydrogen sulfide is pumped from the top of the column to 100%
It was injected at a speed of 1/2 hour and operated continuously for about 35 days. To prevent the peat from drying out, water was sprayed from the top from time to time to adjust the moisture content of the peat to 50-80%. The deodorizing efficiency was calculated by measuring the hydrogen sulfide concentration in the inlet and outlet air of the column using a detection tube. The deodorizing efficiency during the above operation period was 100%. Example 5 Same as Example 4 except that air containing 50-100 ppm acetic acid as a malodorous component instead of 100-150 ppm hydrogen sulfide was blown in at a rate of 100 ppm/hour, and continuous operation was performed for about 18 days. Experiments were conducted in a similar manner. The deodorizing efficiency during this experimental period was also 100%. Example 6 Tank floor area (2.2mx3.3m=) 6.0m ² , tank height 1.0m
The sphagnum peat from the Soviet Union was buried and left in the soil of the pig farm in Example 3, which accounted for 50% of its internal volume of 6 m ^{3 ,} or 3 m ³ , and microorganisms were collected inside the microbial deodorizing bench experimental equipment. Spherical porous eyeball manufactured by Special Wire Mesh Co., Ltd. (diameter 50mm, surface area
165m ² /m ³ , free volume 94%, density 10400 pieces/m ³ ) Approx.
31,000 pieces were filled alternately. Peat moisture content 50
In order to adjust to -80%, the water content was continuously monitored and water was automatically sprayed from the top of the column using a water sprinkler. The foul-smelling air generated from the pig farm was fed into the above bench experimental equipment using a fan (blow capacity 1200 m ³ /hour) while controlling the wind speed to 0.04 - 0.07 m / sec, and it was operated continuously for about 3 months. I did this. The concentration of malodorous components (ammonia, methyl mercaptan, hydrogen sulfide, butyric acid isovaleric acid) in the inlet and outlet air of the bench experimental apparatus was quantitatively measured by the peak area of a gas chromatograph. The deodorizing efficiency was approximately 80% throughout the above operating period. The deodorizing efficiency was maintained at 100% for 38 days after startup, but
The deodorizing efficiency began to gradually decrease from the 39th day, and had dropped to 55% at the end of 3 months. Effects of the Invention As explained in detail above, the deodorizing method using microorganisms of the present invention deodorizes by passing odor gas through a porous layer of peat with a water content of 50% or more, which has fixed deodorizing microorganisms, so that it has the following effects: play. (a) Equipment costs can be kept low because a sludge slurry circulation device is not required. (b) Running costs are low because the operating power is low. (c) Maintenance is easy and maintenance costs can be kept low.

Claims (1)

[Claims] 1. Deodorizing microorganisms are fixed on sphagnum peat of ^100cm3 with an air-dry weight of 11g or less, and this sphagnum peat and 0.1%
The moisture content of the porous deodorizing layer made of the above pore-forming material is reduced to 50%.
This method uses microorganisms to deodorize by passing odor gas through the porous deodorizing layer.