JPS6033282A - Sludge composting method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sludge composting method - a method for treating sludge-like substances containing microorganism-decomposable organic matter such as sludge generated from urban sewage treatment processes and human waste treatment processes. .

Up until now, various methods have been proposed and implemented for the treatment of sludge generated in the urban sewage treatment process and sludge generated in the human waste treatment process. A so-called composting method or fermentation method, in which compost is converted into a compost-like material by the action of microorganisms, is attracting attention.

The basic idea of this method is that after adjusting the moisture content of the material to be treated, it is kept in a so-called aerobic state by making it come into contact with the air, and at this time, aerobic microorganisms are allowed to proliferate and become active in large quantities. It is used to convert sludge into so-called compost, which is chemically and biochemically stable and has low odor.

However, when we examine the conventional methods of composting, we find that it takes a long time to start the aerobic microbial reaction, or that the reaction stops midway through. There are various drawbacks.

In consideration of these points, the present invention provides an effective method for converting sludge-like material into compost-like material in a short time.

That is, the present invention converts various sludge-like substances containing organic matter that can be decomposed by microorganisms into compost-like substances through the activities of microorganisms, mainly aerobic microorganisms. Treating the sludge-like material by completely introducing oxygen or a gas containing oxygen and controlling at least one of state factors such as the temperature, humidity, flow rate, flow rate, atmospheric pressure, and introduction time of the gas. It is characterized by:

The present invention will now be explained in detail according to the embodiments shown in the figures.

FIG. 1 shows a schematic configuration 5!2t of one basic embodiment of the present invention.
- In the flow sheet shown, 1 is a material to be treated, which is various sludge-like substances, which are put into 1 reaction [2].

Air 4 is fed through the lower opening of the reaction tank 2 while controlling the temperature and humidity using a blower 3, a humidifier 5, and a warmer 6.

After this air further comes into contact with the workpiece 1 in the reaction tank 2,
The air is taken out of the reaction tank through the upper opening of the reaction tank, and a part of it is returned to the blower 3 through the pipe 7' for circulation. Of course, during this time some fresh air is constantly being replenished from the outside.

In this way, the present invention can control the temperature and humidity of the air that comes into contact with the object 1 to be treated. As a result, the time required to start the aerobic microbial reaction (hereinafter simply referred to as reaction) is shortened, and once the reaction has started, the desired reaction state Mk is maintained continuously over the target time. can be retained.

As a first practical example of the present invention, an experiment was conducted using sludge generated from the treatment process of urban sewage by the activated sludge method as the object to be treated. As the object to be processed.

The sludge was mechanically dewatered using a filter and press, and had a water content of about 85% by weight. In order to lower this moisture content, a mixture of powdered compost with a moisture content of 10% by weight was mixed to bring the moisture content to 55% by weight.
6 Using the screw set press shown in @a, the diameter is 30 m.
After molding into a round bar shape with a length of 100 mm, the round bar shape is shaped into a shape with a diameter of 1 m and a height of 5 mm as shown in the figure.
m of cylindrical reaction 4W2. There is an opening 2a at the bottom of reaction@2! l1% This opening 2aK is the pipe 7
is connected, and the air from the main blower is sent into the reaction tank 2 through the 710 humidifier 5 and the heater 6. Also reaction 4
There is also an opening 2b at the top of 112, and a part of the exhaust gas from the reaction tank is returned to the suction port of the main blower 6 through a pipe 7' connected to it, and the rest is discharged to the outside while being regulated by the pulp 8a. . In addition, outside air is sent to the suction port of the main blower 3 using another sub-blower 3'. Oxygen in the air passing through the inner metal of the reaction tank 2 is consumed by microbial reactions and decreases, so it is necessary to replenish it. At the meeting a
Send it! They used Sakaki 3' to send in a new and talented foreigner.

Further, the reaction 112 has a to-be-treated material inlet 9a at the upper part and a to-be-treated material outlet 9b at the lower part.

By providing seven tassels 9a' and 9b'l for each, airtightness inside the reaction tank is maintained.

In this way, the temperature t of the air when it flows into 1 reaction tank 2
When kept at -40℃ and 100% relative humidity, the temperature of the object to be treated started to rise immediately after the equipment started operating, and after about 5 FI#s, it reached 40℃, which is the same as the inflow air temperature. Subsequently, the rapid rise t-continues.

After about 12 hours, the temperature reached 65°C. Continue as is V
The apparatus continued to operate for a period of C,ias, during which time the object to be treated continued to maintain a high temperature of 60°C to 65°C. At 100 hours after the start of operation, the operation of the equipment, that is, the air blowing, was stopped and the material to be treated was taken out from the reaction tank.
It had turned into good compost with black color and low odor. however,
In this case, after the temperature of the object to be treated reaches 40°C, the warmer 6
I tried to stop the operation.

Next, as a first comparative example, all of the objects to be treated were treated in the same manner as in the first practical example described above, and after being formed into a round bar shape with a moisture content of 55% by weight, the material was used in the practical example shown in Figure 2. The same equipment was used, except that the lid 9a' of the upper inlet 9a of the reaction tank 2 was replaced.
Open the lid 9b' of the lower outlet 9b and remove the main blower 6.
The auxiliary blower 3' was not operated, and therefore the outside air was brought in from the bottom of the reaction tank by natural ventilation, and was discharged from the top, and the outside air temperature at this time was 15°C on average.

Relative temperature averaged 40 degrees. In this case, it took about 48 hours after all the materials to be treated were introduced into the reaction tank until a clear temperature increase was observed.

Further, approximately 24 hours were required for the temperature of the object to be treated to reach the same high temperature as described above. When the temperature of the object to be treated was left as it was, approximately 12 hours after the temperature reached 60° C., the temperature of the object to be treated began to drop, and the reaction was clearly slowed down.

Furthermore, as a second comparative example, the material to be treated was taken out from the reaction tank 100 hours after the material was added, as in the first comparative example, but it still contained a large amount of unfermented material. It was incomplete compost with a foul odor.

FIG. 3 shows the characteristic curves of changes in the temperature of the processed material with respect to time in the actual example of FIG. 2 of the present invention and the above-mentioned comparative example of Ml. In the actual example, it is clearly expressed that the reaction starts quickly and that a good reaction state is maintained for a long time compared to the comparative example of conventional technology.

In other words, in the practical example of the present invention, the temperature of the object to be treated increased rapidly at the initial stage due to the mere knife-warming effect of the heated air, but as a result, the aerobic microbial reaction The reaction started rapidly, and the temperature of the object continued to rise due to the self-generated heat caused by the reaction, reaching a high temperature of 65°C.

In addition, in the first practical example of the present invention, the air fed into the reaction tank always had a relative humidity of 10 °C, and therefore there was no water loss due to evaporation from the material to be treated, so that good reaction conditions could be maintained for a long time. It was done.

On the other hand, in the first comparative example, the aerobic microbial reaction was slow because the temperature of the material to be treated was low, and it took a long time of 48 hours for the heat to accumulate and start to noticeably increase the temperature. Met. Moreover, the loss of moisture from the object to be treated due to evaporation proceeded at the same time as the temperature started to rise, and since the moisture content appropriate for the reaction was maintained only for a short period of time, the temperature of the object to be treated immediately dropped.

In the first practical example of the present invention, the sludge to be treated was granulated into round bar shapes before being introduced into the reaction tank as described above, but of course there are no restrictions on the shape or size of the granules. It can be used not only in round bar shape but also in spherical shape, sub-ball shape, etc.

There is also no restriction on the granulation method, and transfer granulation, extrusion granulation, compression granulation, crushing granulation, etc. can be used, but among them, the method can be used most effectively in the present invention. The methods are extrusion granulation, compression granulation, and crush granulation.

To illustrate these specific methods, a typical example of the extrusion granulation method uses a screw set press shown in FIG. It is pressed against the press die 13 by the screw 21 holding it.

It is extruded through a hole 13' made in the presser and granulated. In this case, it is molded into a round bar shape, and the round bar is cut by a rotary blade (not shown) that rotates along the outside of the press die. Another specific extrusion granulation method is a method using a ram press as shown in FIG. In the same figure, the workpiece 1 is placed in a ram 1 in a casing 22'.
8 is pressed against the press die 17, and the hole 17 of the press die is
' is extruded and granulated.

The particles are pushed downward by the row 215 that moves while rotating, and are pushed out through the holes 14' formed in the plate 14 and granulated. As described above, the extrusion granulation method is a general term for a method of granulating a material to be processed by pressurizing it and extruding it through the holes of a pressing die, and the specific method is not limited to the one described here. In addition, the compression granulation method refers to two or more rollers 16, 16 rotating the workpiece 1 in contact with each other, as shown in FIG. 6d.
In this method, depressions 16a and 16'a are provided on the surface of these holes 16 and 16', and the material to be processed is compressed and granulated in the depressions. be. At this time, by changing the shape and size of the depressions, the size and shape of the granulated product can be changed arbitrarily, and any shape or size can be obtained in addition to the spherical and sub-spherical shapes.

It can also be formed into a plate shape, a corrugated plate shape, or the like. There is also a method of compressing between two or more plates without using rotating rollers.

Furthermore, the crushing granulation method is as shown in FIG. 6e.

In this method, the object to be processed 1 is compressed into a plate shape between two fully rotating rollers 19 and 19' and then crushed by a crusher 20.

If the material to be treated is granulated in advance before being introduced into the reaction tank, as in the method used in the practical example shown in Figure 2, nitrogen, oxygen, or oxygen-containing gas will pass through the reaction tank. Therefore, the present invention is easier to implement, and its effects are also greater.

Next, a second practical example of the present invention will be explained.

In this case, the material to be treated is the same dehydrated sludge as in the first practical example, but in this case, it was treated to a moisture content of 85% by weight without any adjustment of the moisture content. . However, with this water content, it was impossible to form it into a round bar shape as in the previous example, so many small holes were formed on the many sides and bottom as shown in the side sectional views and slope views in Figures 4a and b. 11' is provided, and the air 4 sent from below is passed through this hole 1.
1' and passed through the object 1 to be treated. This perforated plate 1
1 A large number of them were stacked in a reaction tank 3 as shown in FIG.

In this case, since it is necessary to first reduce the moisture content of the material to be treated to about 60% by weight, which is appropriate for an aerobic microbial reaction, it is decided that only drying will be performed for the first 5 hours, and the humidifier 6 will not operate. , only the warmer 5 is operated, and the pulp 8 on the exhaust side
A and the outside air introduction pulp 8c were fully opened, and the pulp 8b provided in the reflux path was closed to operate the main air blower *3t-, so that all the exhaust gas flowed out to the outside.

Thereafter, the pulp 8bi was closed until the pulp 8a was slightly closed, the pulp 8bi was fully opened, the outside air introduction valve 80 was slightly closed, and the humidifier 6 was also operated to maintain the aerobic microbial reaction state mt for 60 hours.

When the material to be treated was then taken out, it was found that it had turned into good compost.

The shape of the perforated plate used in the second practical example is as follows:
Any type of material is acceptable, such as a simple flat plate with holes or a corrugated plate with holes or slits.

A third practical example of the invention is shown in FIGS. 7a+b. In this case, a large number of hollow round rods 19 are arranged vertically inside the reaction tank 2.
A large number of holes 19''t-drainage pipes 19b are provided on each side of the drain pipe 19b.
They are connected to each other so that the air can communicate with them, and are further connected to the supply/discharge pipes 7 and 7' as shown in Fig. 2. is housed in a reaction tank. In this case, as in the second practical example, the heated and humidified air 4f is sent through the pipe 7, the pipe 19a and the hollow round rod 19 into the reaction chamber, and the air is further fed into the reaction chamber through the holes in the hollow round rods 19. The hollow round d is discharged from 19' into the reaction tank 2, passes through the material to be treated, and is connected to the discharge pipe 19b again. is discharged to.

The material to be treated in this practical example was dehydrated sludge generated from the same urban sewage treatment process as in the JGL example, and the water content was adjusted to 60% by weight to create a good compost-like material. Substance obtained.

In this case, in the actual example, a round rod with many holes is used as the inside, but instead of a round rod, a hollow plate-like body is used and a large number of holes are provided in the inside. Good too. Or the seventh
As shown in the figure, insert the round rod 1 inside which is connected to the feed pipe 19a.
9 may extend over the entire circumference.

In addition, as shown in FIG. 7C, the discharge pipe 19b and the feed pipe 19a are each made of a hollow round rod with a large number of holes, and both are installed above the reactor and inserted into the object to be treated 1. However, in this case, although not shown in the figure, a screw or auger spiral drill is installed on the outside of the container tubes 19a, 19b. If you insert it inside, you can easily insert it.

Also, if this drill is operated at all times during the reaction, the entire material to be treated can be stirred.

In addition, contrary to FIG.
9a and 19b are fixed, and the object to be treated can be introduced from the upper part of the reaction tank, and after the reaction is completed, the object to be processed can be taken out from the lower part of the reaction tank. Further, by using the present invention, thermal energy generated by an aerobic microbial reaction of the material to be treated can be converted into usable energy. For example, if a heat exchanger 21 is connected to the exhaust pipe 7' in the second cause as shown in Figure 8, and a heat medium such as water is heated, hot water can be obtained, and this can be used for heating or other similar reactions. It can be used to heat a tank or a sludge digestion tank (anaerobic methane fermentation tank).

Or exhaust pulp 8avi-open in FIG.

If this exhaust gas is guided to the lower ventilation port of another reaction tank similar to that shown in Fig. 2, the material to be treated in that reaction tank can be heated, and the aerobic microbial reaction in that reaction tank can be started. You can stop. Also, the exhaust pipe 7' in Fig. 8
A heat exchanger 21 is connected to the reactor 2, whereby fresh outside air or oxygen-containing gas 4 is galvanically heated, and the heated gas can be humidified or guided to the lower part of the reaction tank 2 without being humidified.

As described in the above practical examples, the present invention provides an extremely effective method for converting sludge-like material into compost-like material in a short period of time.

In the practical examples of the present invention so far, the case has been described in which the temperature and humidity of air or outside air are controlled. It can also be injected into a reaction tank.

Further, the temperature and humidity of these various gases can be controlled by either or both of them at the same time, and there is no support for controlling either heating or humidification first. It is also possible that full control is performed only during a part of the time during the reaction and not at other times.

Further, if the outside air temperature and outside air humidity are appropriate for the reaction, no control may be performed at all. Instead of humidification, it is also possible to spray or inject water or a liquid containing water onto the object to be treated.

The processed material is not limited to sludge generated from the treatment process of sewage or human waste, but also raw human waste, livestock and animal excrement, etc.
Alternatively, sludge-like substances containing almost all kinds of organic matter are included, such as sludge generated from these processing processes, or sludge generated from various production facilities such as slaughterhouses, food processing plants, and meat processing plants. There are no restrictions on the method, type, or shape of humidifiers, warmers, and blowers. Also, a humidifier may be replaced by a dehumidifier, a warmer by a cooler, and a blower by a suction fan, or in combination.

In addition, in the present invention, at least one of the two state factors, such as the temperature and humidity of the air or oxygen flowing into the reaction tank or the gas containing oxygen, is controlled at the same time, and in some cases, two are mainly controlled simultaneously. In addition, other state factors such as the flow top, flow rate, air pressure, and inflow time of the gas flowing into the reaction tank can also be controlled.

The structure of the reaction tank that can be used in the present invention is not limited. Second. In addition to the ones shown in the third practical example, there is a rotary kiln type, a windrow set, an open pile type, an elevator type, and an auger set.

There are various types such as multi-stage type (Thomas, digester).

Incidentally, it is often necessary to dry the material that has been composted using the present invention, and the method of the present invention is effective in this case, since the blower and humidifier can be operated while all the material to be processed is kept in the reaction tank. However, the operation of the humidifier is stopped, and the outside air is fully heated before being injected into the reaction tank in a multi-level manner.The material to be treated can be easily dried if the humidifier is discharged outside without being circulated. I can do it.

Alternatively, a dedicated drying device may be provided separately from the aerobic microbial reaction tank, and various drying devices such as a rotary kiln type, a belt type, and an open pile type can be used. In addition, methods that require the least amount of energy for drying include methods that use an improved screw press type extrusion granulator or an improved compression granulator, which use far less energy than normal extrusion pressure or compression pressure. By applying a large pressure t-m,
By mechanically dehydrating the processed material and making it dry,
Wear.

[Brief explanation of the drawing]

The drawings are for explaining the invention in detail. FIG. 1 is a 70-sheet showing a schematic block diagram according to one basic embodiment of the present invention, FIG. 2 is a 70-sheet showing a schematic block diagram in a first practical example of the present invention, and FIG. FIG. 4a is a diagram of the temperature characteristic curve of the processed material versus time in the first actual product, the actual product, and the comparative example. 'B' is a sectional view and an oblique view of a perforated plate used in a second practical example of the present invention. FIG. 5 is a flow sheet showing a schematic configuration diagram of the second practical example, and FIG. 6 a, b, c. d and e are simplified diagrams of different granulators that use different pressures when granulating the processed material, and Figures 7a, b, and c are different configurations of the tubes in the reaction tank used in the third practical example. Cross-sectional view. FIG. 8 is a schematic diagram of a case where a heat exchanger is used in a part of the 70-sheet shown in FIG. In the figure, 1 is the sludge material to be treated, 2 is the reaction tank, 5 is the blower, 4 is the air, 5 is the humidifier, 6 is the warmer, 7°7' is the pipe, sa is the valve, 9a+9'a is the lid. Figure 1 Figure 2 Figure 3 Figure 8 Figure 4α Figure 4b Figure 5 Figure 6α Figure 6b Figure 6C Figure 6d Figure 6e 0 e θ2 Figure 7C

Claims (1)

[Scope of Claims] +11 Various sludge-like substances containing organic matter that can be decomposed by microorganisms are converted into compost-like substances by the activities of microorganisms, mainly aerobic microorganisms, in which air is added to a reaction tank containing all the sludge-like substances. Alternatively, oxygen or a gas containing oxygen is introduced, and the temperature and humidity of the gas are adjusted. A sludge composting method characterized in that the sludge-like material is completely treated by controlling at least one of state factors such as flow rate, flow rate, air pressure, and introduction time. (2) A claim characterized in that a sludge-like substance is previously formed or granulated into various shapes such as a round rod or one sphere using mechanical means, and then placed in a reaction tank and subjected to a reaction treatment. The sludge composting method according to item 1.