JPH11335192A - Composting of solid waste from biomass and equipment for that purpose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply air at a low pressure loss and to efficiently dry compost at a low pressure loss after fermentation, by the aerobic fermentation of wet bulk materials or wet coarse particles of solid biomass waste in a fermentor equipped with charging means and exhausting means for oxygen-containing pressurized gas between the bottom bed face and the upper bed face while conducting charging and exhausting gas. SOLUTION: Bulk materials or coarse particles are filled into a fermentor 1 in a state that >=0.01 wt.% ripe compost as seed bacteria is added to solid biomass waste and moisture adjustment of bulk materials, etc., is conducted, and then oxygen-containing gas (e.g. air) is supplied in a state of partial charging into a gas inlet 5 of bottom bed face and a gas inlet 52 of intermediate bed position through a gas-supply pipe 8. The oxygen-containing gas passes through the bed 2 while contacting with the bulk materials, etc., and is exhausted from the fermentor 1 through a gas exit 111 of intermediate bed position and a gas-exhaust pipe 10 above upper bed face in a reduced oxygen content. The oxygen content of exhaust gas is detected by a concentration sensor 12 for exhaust gas and the signal of the sensor 12 is transmitted to an oxygen concentration regulator 13, followed by changing air quantity supplied through a control valve 9 for air charging quantity. Treated bed is discharged as a compost product from a blowdown outlet 4 of the bottom of the fermentor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for composting biological organic solid waste.

[0002]

2. Description of the Related Art For bio-organic solid waste such as municipal solid waste, livestock dung, sewage sludge, and alkaline dewatered sludge cake, each raw material is fed into a fermenter on a silo with no structure in the tank.
Japanese Patent Application Laid-Open No. Sho 54-54 discloses a method in which raw material waste is simply filled to form a continuous bed, air is supplied only from the bottom of the tank, and air passing through the bed is exhausted from the top of the packed bed. No. 101768, JP-A-55-12199
No. 0 publication.

[0003] The conventional silo-filling composting method has the advantage that the tank can be filled with the floor at a high rate and the tank volume can be used effectively. However, if the height of the packed bed is increased in order to reduce the installation area, oxygen is consumed at the bottom of the bed, and not only is the oxygen deficient in the middle and upper portions of the bed, but also the pressure loss increases and the supply is increased. You may have difficulty.

[0004]

As a result of repeated studies to solve the above problems, the present inventors have found the following phenomena.

(1) The air supply is divided not only from the floor bottom but also from an intermediate height between the floor bottom and the floor upper surface. However, in this method, oxygen deficiency is improved only in the floor part very close to the air supply port, and oxygen depletion occurs in the middle and upper parts of the floor as in the conventional method in which air is supplied only from the floor bottom. I found something to do.

The reason is that even if air supply is added in the middle of the bed, oxygen is consumed at the bottom of the bed and diluted with an oxygen-deficient airflow. Further, it was found that the pressure loss was improved as compared with the air supply from only the floor bottom, but was still high.

(2) Therefore, while air is divided and supplied, partial exhaust is attempted from an exhaust port provided slightly below each air supply position.

[0008] As a result, when the thickness of the floor is made appropriate, the supply of air downward from the air supply port directly above the air supply port suppresses the backflow to the exhaust port immediately below the air supply port, thereby substantially depleting oxygen. It has been found that the exhaust gas can be naturally discharged without suction.

In view of the above, it is an object of the present invention to supply oxygen at a low pressure loss during fermentation in a packed continuous bed and to cope with oxygen consumption of the bed. Keep the pressure loss low, and
An object of the present invention is to provide a method and an apparatus for composting biological organic solid waste that can be dried efficiently.

[0010]

The gist of the present invention to achieve the above object is as follows.

[1] Biological properties in which aerobic fermentation is performed by feeding an oxygen-containing gas to a bed, which is continuously filled in the longitudinal direction with wet powdered granules or wet coarse granules of biological organic solid waste. In the method for composting organic solid waste, an air supply means for supplying pressurized oxygen-containing gas between a bottom surface and a top surface of a fermentation tank, and an exhaust means for exhausting without suction are provided. A feature of the present invention is a method for composting a biological organic solid waste.

[2] Biological properties of aerobic fermentation by feeding an oxygen-containing gas to a bed in which moisture-containing powdery granules or moisture-containing coarse particles of biological organic solid waste are continuously filled in the longitudinal direction. In the method for composting organic solid waste, a supply means for supplying pressurized oxygen-containing gas provided between the bottom surface and the top surface of the fermenter and a discharge means for discharging without suction are also provided. An aerobic fermentation process is performed by exhausting air, and after fermentation, a humidity-unsaturated gas is supplied and exhausted in the same manner as during fermentation to dry the floor, and the method for composting a biological organic solid waste is characterized in that the method is as follows.

[3] Biological properties of aerobic fermentation by feeding an oxygen-containing gas to a bed in which moisture-containing granules or moisture-containing coarse particles of biological organic solid waste are continuously filled in the vertical direction. In the organic solid waste composting apparatus, the air supply means for supplying pressurized oxygen-containing gas and the exhaust means for exhausting without suction are alternately arranged in the vertical direction, and the position of the lowermost air supply means Is disposed below the position of the lowermost exhaust means, the interval between the position of any air supply means and the position of the exhaust means directly above it is greater than the distance between the air supply means directly above the exhaust means. An apparatus for composting biological organic solid waste characterized by being arranged to be large.

In the above, it is preferable to arrange a plurality of stages of supply / exhaust means in the vertical direction between the floor bottom surface and the floor top surface.

It is preferable that the air supply and exhaust ports of the air supply and exhaust means open downward.

Further, the exhaust port may be provided with an oxygen concentration measuring means at a downstream side thereof, and the supply amount may be controlled based on the oxygen concentration measured by the oxygen concentration measuring means.

The gap between the exhaust port and the air supply port immediately above the exhaust port is 0.05 to 1 m, preferably 0.1 to 0.4 m.

Furthermore, the moisture content of an arbitrary floor or the humidity of the exhaust gas of an arbitrary floor may be detected, and the amount of air supplied to an air supply port immediately below the floor may be controlled.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The feature of the present invention is that, besides exhausting from the floor bottom, the air is naturally exhausted to the outside of the tank by the pressure of the air supply without being sucked from between the floor bottom and the floor upper surface, and That is, air is supplied from between the floor bottom and the floor top.

The biological organic solid waste of the present invention refers to, for example, garbage, various agricultural and livestock wastes, brewery waste, water treatment sludge, or primary fermentation compost thereof. To these raw material wastes, at least 0.01% or more of aged compost is preferably added as an inoculum, and water is appropriately added so as to be in a range of a water content at which a wet powder or a wet coarse powder can be formed. After adjustment, fill the fermenter.

When the height of the floor exceeds 2 m, a plurality of grids are vertically arranged in the fermenter so that the floor can be prevented from being compacted. By pulling out the floor from the bottom of the fermenter and returning it to the upper part of the floor in the course of the progress of the fermentation, the binding of the floor can be prevented.

In order to adjust the water content required for fermentation to 20% by weight or more, water or a raw material having a high water content may be blended. When the water content is higher than the limit at which the raw material forms coarse grains, aging compost having low water content, sawdust, rice husk, bark, coffee grounds, and the like may be added.

The air supply / exhaust means between the floor bottom and the floor upper surface is not limited to one set. By arranging a plurality of sets of air supply / exhaust means in the vertical direction at predetermined intervals, air supply / exhaust on a high floor can be achieved. Can also respond.

It is preferable that the air supply / exhaust port is opened downward so that air supply / exhaust can be smoothly performed without being closed. The gap between the exhaust port and the air supply port immediately above it can be appropriately selected depending on the physical properties of the floor and the filling height, but is usually 0.05 to 1 m, preferably 0.1 to 0.4 m.

If the floor gap is less than 0.05 m, short-circuiting of the air supply from the air supply port to the exhaust port immediately below becomes large, which is uneconomical.
On the other hand, if the bed gap exceeds 1 m, the supply of oxygen to the bed becomes incomplete and the pressure loss increases, which is disadvantageous both economically and in operation.

[0026]

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

Embodiment 1 FIG. 1 shows a basic flow of an embodiment of the present invention. At the bottom of the fermenter 1, floor bottom air inlet 5,
At the middle height of the tank, the floor middle air inlet 52 and the floor middle air outlet 111 approximately 10 cm below the floor middle air inlet 52.
Place.

A powder or coarse particles obtained by mixing the raw organic solid waste and the waste-derived compost are filled into the tank 1 through the raw material supply port 3. The air 6 is divided and supplied to the floor bottom supply port 5 and the floor middle section intake port 52 through the pump 7, the supply pipe 8, and the supply flow rate control valve 9.

The air having a reduced oxygen concentration after passing through the floor 2 passes through the middle floor exhaust port 111 and the exhaust oxygen concentration sensor 12 as well as the on-floor exhaust pipe 10 and the exhaust oxygen concentration sensor 12 as the exhaust gas 14, and is discharged outside the fermenter 1. To be discharged.

The oxygen concentration in the exhaust gas is measured by transmitting the signal of the exhaust oxygen concentration sensor 12 to the oxygen concentration controller 13 via a signal line 15. If the oxygen concentration is below the preset lower limit of the oxygen concentration, The supply air amount is increased by the supply air flow control valve 9,
If the oxygen concentration exceeds the set upper limit, the supply air amount is reduced by the supply air flow control valve 9.

The air 6 supplied to the tank bottom air supply port 5 is supplied to the floor 2
Rises in the bed while being in contact with the powdery or coarse particles constituting the fermenter 1.
It is discharged outside.

The remaining air flow in the floor 2 is supplied to the air inlet 5 in the middle of the floor.
The fermenter 1 joins with the air 6 supplied separately from the fermenter 1, and is discharged from the upper part of the fermenter 1 as exhaust 14.

By the above-described air supply control, the bed treated by progressing the fermentation is discharged as a compost from the compost discharge port 4 at the bottom of the fermenter to the outside of the fermenter 1.

[0034] Thus, the aerobic fermentation of the moist powder or the coarse moist granules of the biological organic solid waste can be performed with high efficiency.

[Embodiment 2] FIG. 2 is a flow chart in which three sets of supply / exhaust systems in Embodiment 1 are stacked. The floor 2 filled in the fermenter 1 is directed upward from the bottom of the fermenter 1, and the floor bottom air inlet 5, the floor middle air inlets 52, 53, 54, and about 20 cm of each of the above air inlets The lower floor exhaust port 111,
112 and 113 are arranged. The air 6 is supplied separately from the floor bottom supply port 5 and the floor middle supply ports 52, 53, 54 via the pump 7, the supply pipe 8, and the supply flow rate control valve 9.

The air 6 is discharged out of the fermenter 1 through the floor exhaust ports 111 to 113, the floor exhaust pipe 10 and the exhaust oxygen concentration sensors 12 as exhaust 14. The oxygen concentration at each exhaust port is transmitted from an exhaust oxygen concentration sensor 12 to the oxygen concentration controller 13 via a signal line 15 and, if the oxygen concentration exceeds a preset oxygen concentration set value, the supply air flow control valve 9 supplies the oxygen. The amount is reduced, and if less than the set value, the amount of air supply is increased by the air supply flow rate control valve 9.

The air 6 supplied to the floor bottom air inlet 5 of the fermenter 1 is in contact with the powdery or coarse particles constituting the floor 2 and is placed above the floor bottom air inlet 5. Intermediate exhaust port 11
1 is discharged from the fermenter 1 as exhaust gas 14.

The remaining airflow in the floor is supplied to the air supply port 52 in the middle of the floor.
From the fermentation tank, and rises up in the bed through the outlet 112 at the middle of the floor.

Further, the remaining air flow in the bed merges with the air 6 supplied separately from the air supply port 53 in the middle of the floor and rises in the fermenter, and most of the air flows out of the fermenter through the exhaust port 113 in the middle of the floor. Is discharged.

Next, the remaining airflow merges with the air 6 supplied separately from the air supply port 54 in the middle of the floor, rises in the floor, reaches the floor surface, and is discharged out of the fermenter 1 as exhaust 14. .

The floor after the above-described air supply control fermentation treatment is
The resulting compost is discharged out of the fermenter 1 through the compost outlet 4 at the bottom of the fermenter.

[Embodiment 3] FIG. 3 shows an outline of a flow in Example 2 in which air is supplied after the end of fermentation or during the middle of fermentation to dry the bed.

The humidity sensor 1 is provided downstream of the oxygen concentration controller 13.
6, the signal to the air supply flow rate control valve 9 is switched from the oxygen concentration controller 13 to the signal from the humidity controller 18 when switching from fermentation to drying.

A signal from the humidity sensor 16 is transmitted to a humidity controller 18 via a humidity signal line 17, and when the humidity of the exhaust gas is higher than a set value, that is, when the drying is still insufficient, the supply air flow control valve. 9 to increase the air supply. If the value is lower than the set value, that is, if the drying is completed, the air supply amount is reduced or the air supply is stopped.

The air supplied for drying is preferably a humidity-unsaturated gas having a temperature higher than the bed temperature heated by an external heat source.

[0046]

According to the conventional fermentation method in which air is supplied only from the bottom of the bed, the fermentation activity in the upper and lower parts of the bed is inhibited due to lack of oxygen in the upper part of the bed and a decrease in the bed temperature in the lower part of the bed. Because of the large pressure loss of air, it was necessary to supply air at a high pressure.

According to the present invention, not only the supply air is divided and supplied, but also the exhaust gas can be divided and naturally discharged to the outside of the fermentation tank at the pressure of the supply air. Can be maintained within the required range.

Further, since the amount of air supply per air supply port can be reduced, a decrease in the bed temperature near the air supply port is reduced, and the fermentation activity in the height direction of the bed can be maintained at a high level.

Also, since the pressure loss of the supply air can be reduced,
A low pressure air supply system and fermenter can be used,
Equipment costs and operating costs can be reduced.

As described above, the fermentation can be speeded up under conditions that save the area by increasing the bed height and are highly practical.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle flow of an embodiment of the present invention.

FIG. 2 is a diagram showing a principle flow of an embodiment of the present invention.

FIG. 3 is a diagram showing a principle flow of an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fermentation tank, 2 ... Bed, 3 ... Raw material supply port, 4 ... Compost discharge port, 5 ... Floor bottom supply port, 52, 53, 54 ... Floor middle section supply port, 6 ... Air, 7 ... Pump, 8 ... air supply pipe, 9 ... air supply flow control valve, 10 ... floor exhaust pipe, 111, 112,
113: Floor exhaust port, 12: Exhaust oxygen concentration sensor,
13: oxygen concentration controller, 14: exhaust, 15: signal line, 1
6 ... humidity sensor, 17 ... humidity signal line, 18 ... humidity controller.

Claims (3)

[Claims] An aerobic fermentation method in which an oxygen-containing gas is supplied to a bed, which is continuously filled in a longitudinal direction, with a wet powder or a coarse powder of a biological organic solid waste. In the method for composting solid waste, an air supply means for supplying a pressurized oxygen-containing gas between a bottom surface and a floor surface of a fermenter, and an exhaust means for exhausting without suction are provided. Composting method of biological organic solid waste. 2. A bioorganic organic compound which aerobically ferments by supplying an oxygen-containing gas to a bed in which a wet powder or a wet coarse powder of a biological organic solid waste is continuously filled in a longitudinal direction. In the method for composting solid waste, air is supplied and exhausted from an air supply means provided between the floor bottom and the floor upper surface of the fermenter to supply pressurized oxygen-containing gas and an exhaust means provided to exhaust without suction. Aerobic fermentation, and after the fermentation treatment, a moisture-unsaturated gas is supplied and exhausted in the same manner as during fermentation to dry the floor, thereby composting a biological organic solid waste. 3. A bio-organic material which is subjected to aerobic fermentation by feeding an oxygen-containing gas to a bed, which is continuously filled in the longitudinal direction, with a wet-powder granule or a coarse-grained wet bio-organic solid waste. In a solid waste composting device, an air supply means for supplying pressurized oxygen-containing gas and an exhaust means for exhausting without suction are alternately arranged in the vertical direction, and the position of the lowermost air supply means Arranged below the position of the lowermost exhaust means, the interval between the position of any air supply means and the position of the exhaust means directly above it is greater than the distance between the air supply means directly above the exhaust means. A composting apparatus for biological organic solid waste, wherein the composting apparatus is disposed.