JPH06199586A - Method for composting organic sludge and device therefor - Google Patents

Abstract

PURPOSE:To shorten the time in producing org. manure by fermentation of an org. sludge. CONSTITUTION:The org. sludge having 60-75% water content is made to the small lump having 3-20mm max. diameter, and the lump is housed into a fermentation tank provided with a feed/exhaust device and a heating device, and heated up to >=40 deg.C to promote the start of fermentation, then, the oxygen content in the fermentation tank is maintained in 5-20% and the temp. of the org. sludge is maintained at 55-65 deg.C, and after fermentation is almost finished, the org. sludge is dryed and the compost as a product is obtained. In this way, the fermentation is finished for the period one several that of the conventional method and a perfectly fermented org. manure is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for composting organic waste (hereinafter referred to as organic sludge) such as sewage sludge, raw garbage, livestock excrement, and oil squeezing waste. .

[0002]

2. Description of the Related Art The organic sludge, particularly sewage sludge and raw garbage, has been increasing year by year, and it is an urgent need to treat them in some form. Therefore, conventionally, such organic sludge is incinerated into ash to reduce the volume and to be disposed of at a disposal site, or treated at high temperature to manufacture bricks and tiles, or fermented by using microorganisms to be composted. It was used as an organic fertilizer.

However, in the above treatment, disposal is still the same, and there is a problem that the problem of the disposal site will become apparent, and in the other treatment, the bricks and the like obtained are expensive because the equipment is large and expensive. But it was very unprofitable.

Therefore, attention has been paid to a processing method as a relatively simple method, and various studies have been made. The simplest method is a method that has been conventionally used by farmers, etc., in which organic sludge is piled up in a field and naturally fermented. Unrealistic to do. Therefore, this method is scaled up to stack these organic sludges in a large fermentation tank, actively add microorganisms, mechanically stir the organic sludge during fermentation, or in the fermentation tank. Attempts have been made to activate the fermentation of microorganisms by installing an air supply pipe in the stacked organic sludge, but it still took about two months to complete the fermentation. In addition, there is also a problem that the fermentation may not be completed and it may not be a fully-ripened organic fertilizer because the end of fermentation depends on the feeling of the operator.

[0005]

As a result of various investigations in view of the above, the present invention provides a pretreatment of organic sludge so that fermentation can be performed for a short time before the organic sludge is put into a fermenter. , A method of composting organic sludge and a device therefor capable of producing a fully-ripened organic fertilizer in a fraction of a time compared with the conventional method.

That is, according to the method of the present invention, organic sludge having a water content of 60 to 75% is made into a small mass having a maximum diameter of 3 to 20 mm, and the small mass is stored in a fermentation tank equipped with an air supply / exhaust device and a heating device. The heating device raises the temperature of the organic sludge to 40 ° C or more to accelerate the start of fermentation, and then the supply / exhaust device increases the oxygen content in the fermentation tank to 5-20%.
At the same time, the temperature of the organic sludge is kept at 55 to 65 ° C, and after the fermentation is almost completed, the organic sludge is dried to obtain a product compost.

According to the present invention, the organic sludge is rolled into a squid-like shape which is intermittent in the rolling direction, and the sludge is shredded in the lateral direction with respect to the rolling direction to form small lumps or lumps. When storing product compost, incinerator ash of organic sludge, or one or more of hard permeable materials in an organic sludge in a simply dispersed state and storing it in a fermentation tank, or when storing small-sized organic sludge in a fermentation tank It is effective to use a plurality of stages with the maximum stacking height of the organic sludge within 50 cm, or to perform drying after completion of fermentation by operating the air supply / exhaust device and heating device in the fermentation tank. is there.

Further, the apparatus of the present invention comprises at least one pair of rotary rolling rollers for rolling organic sludge having a water content of 60 to 75% so as to be intermittent in the rolling direction, and the organic matter in the form of watermelon. It has a pretreatment device equipped with a pair of rotary groove rollers that mesh with each other by cutting the sludge laterally with respect to the rolling direction to form small pieces with a maximum diameter of 3 to 20 mm and forming unevenness in the lateral direction. In addition, there are multiple stages of stacked organic sludge in a height of 50 cm or less, and there is a heating device that heats the stacked organic sludge to 40 ° C or higher to accelerate the start of fermentation of the organic sludge. In addition, an air supply / exhaust device for circulating air in the stacked organic sludge, a temperature sensor for measuring the temperature of the organic sludge, and an oxygen concentration meter for measuring the oxygen concentration in the atmosphere are used to provide the oxygen concentration in the atmosphere. 5-20%,
It is characterized by having a fermentation tank that automatically adjusts the temperature of the organic sludge to 55 to 65 ° C by the air supply and exhaust device.
At this time, it is more effective to supply air into the fermentation tank by sucking the exhaust side as a supply / exhaust device.

[0009]

As described above, the water content of the organic sludge targeted by the present invention is set to 60 to 75% in advance so that the aerobic microorganisms that carry out composting can be the most active and the organic sludge can be reduced to a small amount. This is because the water content is easy to agglomerate.

The maximum diameter of such organic sludge is 3 to 20.
The reason for making a small lump of mm is that the aerobic microorganisms can ferment the organic sludge uniformly and evenly if it has this size, and thus a mature fertilizer can be obtained in a short time. And if the size of the nodules is less than 3 mm, the air flow will be poor when piled up in the fermentor, fermentation by aerobic microorganisms will not progress sufficiently, and it will take a long time to complete the fermentation. . If the size exceeds 20 mm, fermentation will not proceed to the inside of the granules,
After all, it takes a long time to complete the fermentation. The shape of the small lumps may be any shape such as a small sphere, a small flat shape, or an indeterminate shape, and the maximum crossover dimension of each of them is 3 to 20 mm.
However, about 5 to 10 mm is more preferable.

In order to obtain such small lumps, a pair of rotary rolling rollers that rolls the organic sludge into a squid-like shape and is intermittent in the rolling direction, and the squid-like organic sludge in the rolling direction. On the other hand, a pretreatment device is used which is composed of a pair of rotary groove rollers which are formed by forming unevenness in the lateral direction by shredding in the lateral direction and meshing with each other.

That is, as shown in FIG. 1, the organic sludge is rolled by a pair of rotary rolling rollers (1) having smooth or rough surfaces and having a gap of about 10 mm (A in the figure). This rolled organic sludge becomes squid-like organic sludge (2) with some breaks in the rolling direction. Next, below the above-mentioned rotary rolling roller (1), unevenness having a width of about 10 mm (B in the figure) is provided in the lateral direction, and a rotating groove roller (3) in which these unevenness meshes with each other as shown in FIG. 2 is installed. Then, the squid-like organic sludge (2) is supplied to the groove roller (3). The squid-like organic sludge (2) is laterally shredded by the rotating groove roller (3), and the roller (3)
When it is discharged from, it breaks into small pieces due to its own cut and its own weight.

Next, the small lumps are stored in a fermenter, but at the same time, product compost, incineration ash of organic sludge, and hard breathable material can be mixed. In this way, by partially mixing the product compost, a large amount of aerobic microorganisms responsible for fermentation are added, and fermentation is promoted.
In addition, incineration ash adjusts the water content of organic sludge,
The hard breathable material is for facilitating the fermentation by smoothing the air flow to the inside when a small amount of organic sludge is piled up. The breathable material is preferably a hard material that is not crushed when stacked and has a diameter of 20 mm or more. An example is a hard porous plastic ball.

The fermenter is provided with a plurality of stages made of a plate having a large number of holes so that the air can flow well inside the fermenter. The one covered is good. The small sludge of organic sludge stacked on each stage has a stacking height of 50 cm or less. If this exceeds 50 cm, the small lumps at the bottom are compressed by weight and come into close contact with each other to form larger lumps, making it difficult for air to flow.

An electric heater or a gas burner may be used as a device for heating the inside of the fermentation tank, but in order to heat the inside of the tank quickly and uniformly, heated air is supplied by a blower and at the same time the atmosphere in the tank can be stirred. It is more effective when set to. Further, as the air supply / exhaust device, it is preferable to use a system that sucks air from the ceiling of the tank and at the same time supplies external air from the bottom or bottom of the tank by the suction force. By sucking air from the outside with a negative pressure in the tank as described above, the problem that the malodor of the organic sludge leaks to the outside from the gap of the tank is eliminated, which is excellent in environmental hygiene.

Next, the control of the atmosphere in the fermenter will be described. After stacking the pretreated small organic sludge on each stage in the fermenter, the temperature of the accumulated organic sludge deposits is raised to about 45 ° C by the heating device. The time until this temperature rise depends on the size of the tank and the capacity of the heating device, but
24 hours is enough. This temperature rise activates the activity of microorganisms and starts fermentation. The temperature of the organic sludge piled up by this fermentation naturally rises, and since oxygen in the atmosphere is consumed by the start of fermentation, the oxygen concentration in the atmosphere gradually decreases.

At this time, the optimum fermentation temperature is about 60 ° C.,
As the fermentation progresses, the temperature rises further, and when the temperature of the sediment exceeds 65 ° C, the activity of the aerobic microorganisms responsible for the fermentation suddenly decreases. Therefore, at this time, the outside air is introduced by the air supply / exhaust device to lower the temperature to around 60 ° C. Further, when the oxygen concentration in the atmosphere is less than 5%, fermentation of microorganisms is also stagnation. Therefore, also at this time, the outside air is introduced by the air supply / exhaust device to raise the oxygen concentration. By simultaneously and repeatedly adjusting such temperature and oxygen concentration, fermentation of the small sludge-like organic sludge proceeds smoothly. According to the present invention, the time from when the temperature of the sediment rises to about 60 ° C to the end of fermentation is about 48 hours.

When the fermentation is completed, the temperature of the sediment becomes 60
Since the temperature will naturally decrease from around 0 ° C, the fermented sediment at that point is transferred to the drying process. The drying can be carried out by operating the heating device and the air supply / exhaust device at the same time in the fermentation tank, but may be carried out by an external drying device. In the present invention, the maximum drying in the fermenter is
It only needs to be done for 24 hours, which results in a ripe product compost. As described above, it takes about 4 days to commercialize a fully-ripened organic fertilizer using organic sludge as a raw material, which is much shorter than in the past.

[0019]

EXAMPLES The present invention will be further described with reference to examples.

Sewage sludge having a water content of 75 to 85% was made into small pieces having a particle size of about 10 mm by the above pretreatment device. Then, the sludge incineration ash with a water content of 15 to 25%, the returned product compost, and the porous plastic balls are mixed with the above-mentioned small lumps so that the total water content is
As shown in Table 1, five types of samples A to E were prepared so as to have a concentration of 60 to 65%. The sample of 100% sewage sludge is
It was not adopted because it is very difficult in terms of time and cost to dry it to a predetermined water content of 60 to 65%. A commercially available microorganism was also added as a promoter, but the amount was neglected because of its small amount.

[0021]

[Table 1]

The blending method of these blends is the three types shown in Table 2, and the initial environmental temperature in the fermenter is 10 ° C or less, 25 ° C and 45 ° C, and these are combined as shown in Table 3. It was composted. After the temperature of these compounds reached 60 ° C and the fermentation was activated, the temperature of the compounds was adjusted to about 60 ° C and the oxygen concentration in the tank was adjusted to about 5% by operating the air supply / exhaust device.

[0023]

[Table 2]

[0024]

[Table 3]

By combining the conditions as described above, the compound of each compounding type is piled up in a fermenter in the form of a shelf having seven steps with a bottom size of 1.5 m square and a stacking height of about 40 cm. Fermentation was performed and the results are shown in Tables 4-6.

[0026]

[Table 4]

[0027]

[Table 5]

[0028]

[Table 6]

Numbers such as 16 Hr in the table indicate the time until the temperature of the compound reaches 60 ° C. after the compound is put into the fermenter.
Finally, when the whole is in a good fermentation state, it is described as (overall), and when approximately 1/3 of the formulation is judged to be anaerobic fermentation (mura is large), it is further described as the target aerobic fermentation ( Those that did not reach 60 ° C and became so-called rotten were described as (anaerobic fermentation). In addition, * in the table represents conditions other than the implementation conditions, and the state of fermentation was judged visually and by smell.

The following is clear from the table. If the sample is artificially stirred or kneaded in an attempt to mix it uniformly, the sample that has been made into agglomerated and finely divided particles for improving air permeability becomes a nodule-like shape, which is the worst compounding method. The best results were obtained by sprinkling the agglomerated sample with water control and fermentation accelerators such as returning compost (simply mixed in a dispersed state). The effect of environmental temperature is greater than that of the compounding type (some additives). In particular, if the temperature rise of 60 ° C is not achieved within 48 hours, aerobic fermentation does not occur. If the initial environmental temperature is maintained at 45 degrees where microbial change occurs, it will shift to aerobic fermentation in 16 to 24 hours, and thereafter
The sample temperature around 60 ℃ can be maintained.

As described above, the initial environmental temperature in the fermenter is 40 ° C.
With the above, if it is a blended mixture without stirring, regardless of the blending format, the temperature will be 60 ° C, which is optimal for fermentation within 18 hours after being added to the fermenter, and the whole will be in a good fermentation state. The fermentation time was 48 hours or less in all cases.

[0032]

As described above, according to the present invention, it is possible to obtain an organic fertilizer in which the fermentation time of the organic sludge is much shorter than in the conventional case and the organic fertilizer is fully ripe. Therefore, since compost can be obtained from the organic sludge within a few days, the industrially significant effect is achieved such that the organic waste that has been mainly discarded conventionally can be easily used as a fertilizer.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a pretreatment apparatus according to the present invention.

FIG. 2 is a plan view showing a rotary groove roller of the pretreatment device according to the present invention.

[Explanation of symbols]

 1 rotary rolling roller 2 squid-like organic sludge 3 rotary groove roller

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshinori Inoue 1-13-4 Koteshi-cho, Tokorozawa, Saitama Prefecture East Japan Fusion Co., Ltd.

Claims (7)

[Claims] 1. An organic sludge having a water content of 60 to 75% has a maximum diameter of 3
A small lump of ~ 20 mm is stored in a fermentation tank equipped with an air supply / exhaust device and a heating device, and the temperature of the organic sludge is controlled by the heating device.
After raising the temperature to 40 ° C or higher to accelerate the start of fermentation, the oxygen amount in the fermenter is kept at 5 to 20% by the air supply / exhaust device, and at the same time, the temperature of the organic sludge is kept at 55 to 65 ° C, and the fermentation is almost completed. After that, the organic sludge is dried to obtain a product compost, which is a method for composting an organic sludge. 2. The composting method according to claim 1, wherein the organic sludge is rolled into a caustic shape that is intermittent in the rolling direction, and the sludge is shredded in the lateral direction with respect to the rolling direction to form small pieces. 3. A small-sized organic sludge, product compost,
The incineration ash of organic sludge and one or more hard breathable materials are simply mixed and stored in a fermenter.
The composting method described. 4. When storing the lumped organic sludge in a fermenter, a plurality of stages having a maximum stacking height of the organic sludge of not more than 50 cm are provided. How to compost. 5. Drying after completion of fermentation is performed by operating the air supply / exhaust device and heating device in the fermentation tank.
4. The composting method according to any one of 4 above. 6. At least one pair of rotary rolling rollers for rolling an organic sludge having a water content of 60 to 75% in the rolling direction and intermittently in the rolling direction, and the water-dried organic sludge in the rolling direction. On the other hand, the maximum diameter is 3 to 20 mm by laterally chopping.
It has a pretreatment device equipped with a pair of rotating groove rollers that form unevenness in the lateral direction and mesh with each other, and there are multiple steps in which the small lumps of organic sludge are piled up within a height of 50 cm. The organic sludge is installed in stages and has a heating device that heats the stacked organic sludge to 40 ° C. or more to accelerate the start of fermentation of the organic sludge, and a supply / exhaust device that circulates air in the stacked organic sludge, and the organic material. Equipped with a temperature sensor to measure the temperature of sludge and an oxygen concentration meter to measure the oxygen concentration in the atmosphere, the oxygen concentration in the atmosphere is 5 to 20%, and the temperature of the organic sludge is 55
An apparatus for composting organic sludge, comprising a fermentation tank which is automatically adjusted to a temperature of up to 65 ° C by the air supply and exhaust device. 7. The composting device according to claim 6, wherein air is supplied to the fermentation tank by sucking the exhaust side as a supply / exhaust device.