KR102345126B1 - equipment for sludge treatment - Google Patents

Abstract

The present invention relates to a sludge treatment device for fermenting and drying wastewater sludge, which comprises: a sludge storage part for temporarily storing the sludge; a sludge fermentation part for receiving the sludge from the sludge storage part and fermenting the same with microorganisms; a microorganism storage part for storing the microorganisms input to the sludge fermentation part; a scum processing part for removing odors from scum generated in the sludge fermentation part; and a drying part for removing moisture by receiving the fermented sludge from the sludge fermentation part. The sludge fermentation part comprises: a fermentation tank providing a predetermined space for fermentation; a sludge input pipe formed on an upper part of the fermentation tank; a scum discharge pipe formed on an upper part of the fermentation tank; a lower stirrer formed in a lower part of the fermentation tank; an air injection pipe formed in a lower part of the fermentation tank; and a fermentation product discharge pipe formed in a lower part of the fermentation tank, wherein a side of the fermentation tank has an air bubble guide plate for temporarily suppressing the rise of the air bubbles injected from the air injection pipe. The sludge treatment device is capable of controlling the amount of oxygen required by aerobic microorganisms in various time steps in the fermentation process of the sludge.

Description

Sludge treatment equipment {equipment for sludge treatment}

The present invention relates to a sludge treatment apparatus, and more particularly, fermenting and drying sludge containing food waste, industrial wastewater, domestic sewage, etc. to reduce the moisture content, and to recycle the dried sludge as fertilizer. It's about the device.

In general, in a sewage treatment process, a large amount of organic solids derived from food waste are included, and the object to be treated in which these solids and water are mixed is called sludge. Sewage sludge is separated in a state of discharging water during the sewage treatment process, and even after this dewatering process, the content reaches 70-90%. Such sludge is generated not only in the sewage treatment process but also in livestock excreta and industrial waste, so it is difficult to treat.

Even after dehydration, sludge has a high water content and contains various kinds of organic matter, so it easily decomposes and has a bad effect on the environment, such as giving off a bad odor during the decay process. The simplest method to prevent sludge from decay is to use external energy to dry the sludge. As a prior literature on this, there is Korean Patent Application Laid-Open No. 2017-0087013. The prior literature discloses a step of mixing sludge and oil in a mass ratio of 1:0.5 to 1:1.5, and a step of reducing moisture by using steam by introducing the mixture into a series-type multi-stage evaporator; and centrifuging the mixture to first separate oil, wherein at least one of the multi-stage evaporators is operated under reduced pressure, the operating temperature of the preceding evaporator is lower than the operating temperature of the subsequent evaporator, and the boiling point of the oil is the moisture Disclosed is a sludge treatment method characterized in that 30 ° C. to 80 ° C. higher than the steam temperature supplied in the reduction step. However, the sludge treatment method presented in the prior literature is not preferable because excessive external energy is included in the operation of the evaporator in the sludge treatment process, and secondary environmental pollution may occur in the process of using such external energy.

Another method for treating sludge is to decompose and dry organic matter contained in the sludge through fermentation. The sludge treatment method using fermentation treatment is environmentally friendly and has the advantage that the product decomposed by microorganisms in the fermentation process can be recycled as fertilizer or the like. As a prior document on a technology for treating sludge through fermentation, there is Korean Patent Registration No. 1803895. The prior literature discloses a first fermenter 110 in which a first sludge fermentation space 112 capable of fermenting the input sludge is formed, and is provided in the lower portion of the first fermenter 110 and the first sludge fermentation space 112. The first lower air supply device 120 for supplying air to the It is installed in the transverse direction at the center of the first fermenter 110 and provided with central air supply devices 146 and 148, to the first sludge fermentation space 112 through the central air supply devices 146 and 148. A first fermentation device 100 including a first stirring device 140 for supplying air and agitating the input sludge; and a second fermenter 210 having a second sludge fermentation space 212 in which the sludge that has passed through the first fermentation device 100 can be input and fermented is provided in the lower portion of the second fermenter 210 and 2 The second lower air supply device 220 for supplying air to the sludge fermentation space 212 and the second agitator 240 installed in the transverse direction in the center of the second fermenter 210 and agitating the input sludge ), including a second fermentation apparatus 200; is disclosed with respect to a sludge fermentation apparatus comprising.

In the fermentation process of sludge, aerobic microorganisms are generally used, and in the fermentation process by such aerobic microorganisms, the fermentation rate and metabolic pathway are changed by the amount of oxygen contained in the treatment object. However, the sludge treatment apparatus disclosed in Korea Patent Registration No. 1803895, which is the preceding document, has a disadvantage in that the amount of oxygen dissolved in the sludge cannot be precisely controlled. Therefore, there is a high need for the development of a sludge treatment device that can precisely control the amount of dissolved oxygen in the fermentation process.

Therefore, the problem to be solved by the present invention is to provide a sludge treatment apparatus capable of controlling the amount of oxygen required by aerobic microorganisms in various time steps in the fermentation process of the sludge.

The present invention provides a sludge treatment apparatus for fermenting and drying wastewater sludge in order to achieve the above object. , a microorganism storage unit for storing microorganisms input to the sludge fermentation unit, a scum treatment unit for removing odor from the scum generated in the sludge fermentation unit, and the sludge fermented in the sludge fermentation unit to receive and remove moisture for the sludge fermentation unit, a fermentation tank providing a predetermined space for fermentation, a sludge input pipe formed on the upper part of the fermentation tank, a scum discharge pipe formed on the upper part of the fermentation tank, and a lower part of the fermentation tank It includes a lower stirrer formed, an air injection tube formed in the lower portion of the fermentation tank, and a fermentation product discharge tube formed in the lower portion of the fermentation tank, and the side of the fermentation tank temporarily suppresses the rise of air bubbles injected from the air injection tube It provides a sludge treatment device, characterized in that the air bubble guide plate is formed for

According to one embodiment of the present invention, the fermentation tank has a rectangular cross section in the horizontal direction, and the bubble guide plate is inclined downward from both sides of the fermentation tank and may be made of a plurality of plates extending to the center of the fermentation tank. have.

According to another embodiment of the present invention, the inclination of the air bubble guide plate can be controlled so that the inclination can be switched to be inclined in the upward direction.

According to another embodiment of the present invention, it further comprises an upper stirrer formed on the upper portion of the fermentation tank, wherein the lower stirrer moves the sludge treatment liquid in the upper direction of the fermentation tank, and the upper stirrer is in the lower direction of the fermentation tank to move the sludge treatment liquid.

According to another embodiment of the present invention, while the lower stirrer rotates, the bubble guide plate is inclined downward, and while the upper stirrer rotates, the air bubble guide plate can be controlled to tilt upward.

The sludge treatment apparatus of the present invention can treat sludge having a content rate of up to 85% by sequentially applying the fermentation and drying steps, and in this case, the weight of the sludge after treatment can be reduced by 85% compared to the original.

In addition, the sludge treatment apparatus of the present invention can maximize the residence time of the air bubbles dispersed in the sludge treatment liquid by applying an air bubble guide plate to the fermentation tank.

In addition, since the bubble guide plate applied to the sludge treatment apparatus of the present invention can freely control the inclination, the amount of dissolved oxygen in the fermentation step requiring a relatively large amount of dissolved oxygen for fermentation and the fermentation step in which a relatively small amount of dissolved oxygen is required for fermentation are time-sequentially controlled. The range can be freely controlled.

In addition, since the sludge treatment apparatus of the present invention has a stirrer installed at the upper and lower portions, respectively, it is possible to induce a change in the dissolved oxygen amount in each fermentation step by interlocking the operation of the stirrer and the inclination control of the bubble guide plate.

1 schematically shows each configuration and coupling relationship of the sludge treatment apparatus of the present invention.
Figure 2 shows the basic configuration of a fermentation tank applied to the sludge treatment apparatus of the present invention.
Figure 3 shows an embodiment of the bubble guide plate installed in the fermentation tank applied to the sludge treatment apparatus of the present invention.
4 shows an example in which the inclination of the air bubble guide plate is controlled in the sludge treatment apparatus shown in FIG.
Figure 5 schematically shows the movement path of the air bubble by the control method of the air bubble guide plate shown in FIG.
6 is a view for explaining a method of controlling the stirrer and the bubble guide plate in the fermentation tank installed with the agitator at the upper and lower parts.
7 is a view for explaining that the bubble guide plate is controlled at different inclinations from both sides of the fermentation tank according to an embodiment of the present invention.
8 is a view for explaining the structure of a fermentation tank in which an air bubble guide plate is spirally installed according to an embodiment of the present invention.

The present invention is a sludge treatment device for fermenting and drying wastewater sludge, a sludge storage unit for temporarily storing the sludge, a sludge fermentation unit receiving sludge supplied to the sludge storage unit and fermenting it with microorganisms, and input to the sludge fermentation unit A microbial storage unit for storing microorganisms to be used, a scum processing unit for removing odor from the scum generated in the sludge fermentation unit, and a drying unit for receiving the sludge fermented by the sludge fermentation unit and removing moisture, wherein the The sludge fermentation unit includes a fermentation tank providing a predetermined space for fermentation, a sludge input tube formed on the upper portion of the fermentation tank, a scum discharge tube formed on the upper portion of the fermentation tank, a lower stirrer formed on the lower portion of the fermentation tank, and the fermentation tank It includes an air injection tube formed in the lower part of the fermentation tank and a fermentation product discharge tube formed in the lower portion of the fermentation tank, and an air bubble guide plate is formed on the side of the fermentation tank to temporarily suppress the rise of air bubbles injected from the air injection tube. characterized in that

The sludge treatment apparatus of the present invention is characterized in that the sludge is fermented with an aerobic microorganism, dried, and treated. At this time, in the fermentation process by aerobic microorganisms, the fermentation rate and metabolic pathway are affected by the amount of dissolved oxygen contained in the sludge treatment liquid. Therefore, for efficient and fast fermentation, it is necessary to quickly control the amount of dissolved oxygen contained in the sludge treatment liquid in a wide range during the fermentation process, and in this case, it is possible to significantly increase the fermentation rate.

The sludge treatment apparatus of the present invention applies an air bubble guide plate of various structures to control the time that air bubbles injected into the sludge treatment liquid inside the fermentation tank remain in the solution, and interlocks the operation of the stirrer and the inclination of the air bubble guide plate It has controllable features.

The present invention will be described in more detail below with reference to the drawings.

1 schematically shows each configuration and coupling relationship of the sludge treatment apparatus of the present invention. 1, the sludge treatment apparatus 100 of the present invention includes a sludge storage unit 10, a sludge fermentation unit 20, a microorganism storage unit 30, a drying unit 40, a scum processing unit 50, and a fertilizer. It includes a processing unit (60). The sludge storage unit 10 is a means for temporarily storing the sludge in order to receive the sludge containing various organic substances and supply it to the sludge fermentation unit 20 . The sludge storage unit includes a sludge inlet and outlet, and may be coupled to the sludge fermentation unit 20 by a connection pipe including a valve. The sludge fermentation unit 20 provides a space for fermenting sludge with microorganisms, is connected to the microorganism storage unit 30 through a valve and a connection pipe, and is stored in the microorganism storage unit 30 at a necessary time by controlling the valve. Microorganisms may be injected into the sludge fermentation unit 20 . The drying unit 40 is a means for receiving the fermented sludge from the sludge fermentation unit 20 and removing the remaining moisture using a heater, and the drying unit and the sludge fermentation unit are connected with a valve and a connection pipe. The scum processing unit 50 is a means for removing scum generated in the fermentation process and odor gas generated in the drying process and discharging to the outside, and may include a flame for incineration or ozone treatment means for chemical decomposition. The scum processing unit 50 may be connected to the sludge fermentation unit 20 and the drying unit 40 .

Below, the configuration and effects of the sludge fermentation unit including the characteristic configuration of the present invention will be described in more detail.

Figure 2 shows the basic configuration of a fermentation tank applied to the sludge treatment apparatus of the present invention. 2, the sludge fermentation apparatus 200 includes a fermentation tank 201, a heater 202 for controlling the internal temperature of the fermentation tank, a sludge input pipe 203 for injecting sludge into the fermentation tank, A lower stirrer 204 installed in the lower part of the fermentation tank, an air injection pipe 205 installed in the lower part to inject air into the sludge treatment liquid stored in the fermentation tank, and a fermentation product discharge pipe for discharging the fermentation-completed sludge to the outside (206), includes a scum discharge pipe 207 for discharging the scum generated in the fermentation process to the outside. Valves V1 to V5 for controlling the flow of fluid are installed between the sludge input pipe 203, the scum discharge pipe 207, the fermentation product discharge pipe 206, and the air injection pipe 205 and the fermentation tank.

The fermentation tank 201 provides a space in which sludge is stored and fermentation proceeds, and the sludge treatment liquid is stored in the internal space during fermentation to have a predetermined height. The heater 202 may be a heating means using steam or small thermal oil as a means for controlling the temperature of the sludge treatment liquid stored in the fermentation tank to a temperature suitable for fermentation, and if necessary, it can control the temperature change in stages or continuously. can Although the drawing shows the heater on the side of the fermentation tank, the heater may be installed on the side or the lower side of the fermentation tank, and may consist of a plurality of heaters. The lower agitator 204 agitates the sludge treatment liquid so that microorganisms and air bubbles are uniformly mixed. do. In this case, the rotor blade may have a structure for pushing the fluid in a direction parallel to the rotation axis and a force for pushing the fluid in a direction perpendicular to the rotation axis. Such a structure may be the same structure as a general fan blade, and the blade may have a structure inclined at a predetermined angle in the direction of the rotation axis. The air injection pipe 205 is a means for injecting air bubbles into the sludge treatment liquid 300 stored in the fermentation tank, and a gas compression means such as an air compressor, a bubbler or It may include additional components such as ejectors.

Figure 3 shows an embodiment of the bubble guide plate installed in the fermentation tank applied to the sludge treatment apparatus of the present invention. Referring to FIG. 3 , the sludge fermentation apparatus 100 includes all of the configurations shown in FIG. 2 , and further includes air bubble guide plates 211a and 211b. At this time, the fermentation tank includes a rectangular parallelepiped-shaped wall having a horizontal cross section. On both walls of the fermentation tank, the bubble guide plates (211a, 211b) extend to the center of the fermentation tank while inclining in the lower direction of the fermentation tank. The air bubble guide plates 211a and 211b installed inclined in this way allow the air bubbles to stay for a certain time between the bubble guide plate and the wall of the fermentation tank to increase the time for oxygen to dissolve in the sludge treatment liquid 300. do. At this time, the bubble guide plates (211a, 211b) may be installed in a downwardly inclined form, but the inclination is reversed by the hinge and the driving unit formed between the fermentation tank side wall and the bubble guide plates (211a, 211b). can Between the side wall of the fermentation tank and the air bubble guide plate, a polymer film is attached downward to prevent air bubbles from passing therebetween. The bubble guide plate can be extended in the central direction with a length of 0.1 to 0.3 times the width of the fermentation tank, and the inclination of the bubble guide plate can be controlled in the range of -30 degrees to +30 degrees relative to the horizontal. . The length and inclination angle in the extension direction of the bubble guide plate is a numerical range considering the stirring efficiency of the agitated sludge treatment liquid and the time the air bubble temporarily stays between the wall and the bubble guide plate. The lower stirrer 204 is installed in the lower central portion of the fermentation tank 201 , and the air injection pipes 208a and 208b are formed in symmetrical positions on both sides of the lower stirrer 204 . The air injection pipes 208a and 208b are connected to the air compressor 220 through a valve V5.

4 shows an example in which the inclination of the air bubble guide plate is controlled in the sludge treatment apparatus shown in FIG. Referring to (a) of Figure 4, the air bubble guide plates (211a, 211b) can be controlled in a downwardly inclined form from both sides, referring to (b), the air bubble guide plates (211a, 211b) are both sides At the same time, it can be controlled in an upwardly inclined form. Controlling the inclination of the bubble guide plate in this way is to step-by-step control of the time the air bubbles supplied to the sludge treatment liquid stay inside the treatment liquid, and the air bubble guide plates on both sides are controlled to have the same inclination at the same time period. can be

Figure 5 schematically shows the movement path of the air bubble by the control method of the air bubble guide plate shown in FIG. Referring to (a) of Figure 5, when the lower stirrer 204 rotates in a state in which the air bubble guide plates 211a and 211b are all inclined downward, the air bubbles injected into the air injection tubes 208a and 208b are fermented. The tank 201 is dispersed and moved radially upward from the lower center of the tank 201 . The flow of the fluid rising upward forms the opposite flow that descends downward from the side of the fermentation tank, and a vortex is sometimes formed around the bubble guide plate, but only the main flow is shown with arrows in the figure. At this time, air bubbles are introduced into the lower part of the air bubble guide plate (211a, 211b), and the introduced air bubble rises by buoyancy and stays trapped in the space between the air bubble guide plate and the wall of the fermentation tank (with black air bubbles). indicated). In this way, the air bubbles staying in the space are secured a time to dissolve in the sludge treatment liquid, so that the amount of dissolved oxygen can be increased. Then, referring to (b) of Figure 5, when the position of the bubble guide plates (211a, 211b) is controlled in an upwardly inclined form while the lower agitator 204 is operating, between the bubble guide plate and the fermentation tank Air bubbles that stay in space are released above the water surface as they rise with buoyancy and fluid flow. In this way, periodically raising and lowering the bubble guide plate while stirring functions to prevent the air bubbles from staying in the sludge treatment liquid for too long. If the bubble stays in the same area for too long, it is advantageous to periodically change the position of the bubble, since the dissolution of oxygen in the sludge treatment liquid in the surrounding area is saturated. The fermentation induction process of the fermentation tank described in FIG. 5 may consist of "supply of sludge treatment liquid - operation of heater - repetition of rise and fall of air bubble guide plate during operation of lower stirrer". The ascending and descending period of the bubble guide plate is preferably 15 to 30 seconds apart. If the period is shorter than this, the durability of the equipment deteriorates due to frequent operation of the bubble guide plate, and if it is longer than this, the bubble retention effect by the bubble guide plate is too low.

It is possible to additionally install an upper stirrer together with a lower stirrer in the fermentation tank applied to the sludge treatment apparatus of the present invention. The upper agitator functions to more effectively control the movement path of the air bubbles together with the function of allowing the agitation of the sludge treatment liquid to be performed together (or in stages) at the upper and lower portions.

6 is a view for explaining a control method of the stirrer and the bubble guide plate in the fermentation tank installed with the agitator at the upper and lower parts. Referring to FIG. 6(A), when the upper agitator 204' operates (at this time, the lower agitator does not operate), the flow of the fluid formed in the sludge treatment liquid 300 is formed radially downward, and downward As the descending fluid rises toward the side of the fermentation tank, a local vortex is formed. However, arrow marks for fluid flow and vortex in opposite directions are omitted from the drawings. While the upper stirrer 204' is operating, the bubble guide plates 211a, 211b both maintain a downwardly inclined shape, and at this time, the air bubbles injected through the air injection pipes 208a, 208b are located in the center of the fermentation tank. It moves to the side of the fermentation tank through a flow opposite to the fluid flow of The air bubbles moved in this way are introduced into the space between the bubble guide plate and the side wall of the fermentation tank along the slope of the lower part of the bubble guide plate. stay (marked with black air bubbles). Then, referring to FIG. 6 (b), when the operation of the upper stirrer 204' stops, the operation of the lower stirrer 204 starts, and at this time, the air bubble guide plates 211a and 211b rise. At this time, an ascending flow occurs in the center of the fermentation tank by the operation of the lower agitator 204, and the air bubbles remaining in the clogged space along this flow may rise upward. In this way, if the upper stirrer and the lower stirrer are used together and the inclination of the bubble guide plate is controlled together according to the operation of the stirrer, the time the air bubbles stay inside the sludge treatment liquid can be more effectively controlled, and efficient fermentation can be induced. have. The ascending and descending period of the bubble guide plate is preferably 15 to 30 seconds apart. If the period is shorter than this, the durability of the equipment deteriorates due to frequent operation of the bubble guide plate, and if it is longer than this, the bubble retention effect by the bubble guide plate is too low.

The fermentation tank applied to the sludge treatment apparatus of the present invention may include an air bubble guide plate that is controlled with inclinations in different directions. In this way, when the air bubble guide plate is controlled in different directions with a slope, it is advantageous to alternately operate the two air injection tubes 208a and 208b.

7 is a view for explaining that the control at different inclination from both sides of the fermentation tank of the bubble guide plate according to an embodiment of the present invention. Referring to (a) of Figure 7, the left air bubble guide plate (211b) is inclined downward and in the state in which the right air bubble guide plate (211a) is controlled to tilt upward, the left air injection pipe (208b) Air is injected through and the air injection pipe 208a on the right may be maintained in a closed state. In order to control in this way, it is necessary to install and control a separate valve in each air inlet pipe. In this state, a lot of air bubbles are relatively distributed on the left side of the fermentation tank, and it can effectively stay in the lower part of the air bubble guide plate inclined downward. 7 (b), when the left air injection pipe 208b is closed and the right air injection pipe 208a is changed to an open state, the left air bubble guide plate 211b rises and the right air The drop guide plate 211a is lowered. It can be continuously changed to the states of (A) and (B) while fermentation is in progress. The rising and falling cycle of the bubble guide plate is preferably 30 to 1 minute intervals. If the period is longer or shorter than this, the effect of air bubbles staying in the left and right air bubble guide plates may be too small due to the formation of vortices.

It is possible to apply an air bubble guide plate formed in a spiral direction to the fermentation tank applied to the sludge treatment apparatus of the present invention. To this end, the fermentation tank may have a circular cross section in the vertical direction, the bubble guide plate extends from the side of the fermentation tank to the central part while having a predetermined width, and the bubble guide plate spirals along the side of the fermentation tank in the form of a column can be extended upwards. At this time, the air bubble guide plate may be installed in a downwardly inclined form. Hereinafter, this will be described in more detail with reference to FIGS. 7 and 8 .

8 is a view for explaining the structure of a fermentation tank in which an air bubble guide plate is spirally installed according to an embodiment of the present invention. Referring to (b) of Figure 8, the fermentation tank 201 has a cylindrical shape, the air bubble guide plate (211c') is formed in a spiral along the side wall. The spiral-shaped bubble guide plate (211c') functions to efficiently dissolve oxygen in the sludge treatment liquid by moving it spirally in an area adjacent to the side wall of the fermentation tank while rising by the buoyancy of the air bubbles. Referring to FIG. 8(A), the bubble guide plate 211c extends in the direction of the center of the fermentation tank while being inclined downward. The inclination of this air bubble guide plate is to help the air bubbles move spirally by being constrained in the area adjacent to the fermentation tank wall. At this time, the length of the bubble guide plate extending in the direction of the center of the fermentation tank may be 0.1 to 0.3 times the diameter of the fermentation tank. The bubble guide plate of this structure may have the advantage that there is no need to control the change in inclination.

The above description describes the technical idea of the present invention using one embodiment, and various modifications and variations are possible by those skilled in the art to which the present invention pertains without departing from the essential characteristics of the present invention. Accordingly, the embodiments described in the present invention are not intended to limit the technical spirit of the present invention, but to illustrate, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: sludge treatment device 10: sludge storage unit
20: sludge fermentation unit 30: microorganism storage unit
40: drying unit 50: scum processing unit
60: fertilizer treatment unit
200: sludge fermentation device 201: fermentation tank
202: heater 203: sludge inlet pipe
204: lower stirrer 204': upper stirrer
205: air injection pipe 206: fermentation product discharge pipe
207: scum discharge pipe 208a, 208b: air injection pipe
211a, 211b, 211c, 211c': air bubble guide plate
220: air compressor 300: sludge treatment liquid
400: air bubble V1 to V5: valve

Claims (5)

A sludge treatment apparatus for fermenting and drying wastewater sludge,
a sludge storage unit for temporarily storing the sludge;
a sludge fermentation unit that receives the sludge from the sludge storage unit and ferments it with microorganisms;
a microorganism storage unit for storing microorganisms input to the sludge fermentation unit;
a drying unit for receiving the fermented sludge from the sludge fermentation unit and removing moisture; and
A scum processing unit for removing scum generated in the sludge fermentation unit and odorous gas generated in the drying unit,
The sludge fermentation unit includes a fermentation tank providing a predetermined space for fermentation, a sludge input tube formed on the upper portion of the fermentation tank, a scum discharge tube formed on the upper portion of the fermentation tank, a lower stirrer formed on the lower portion of the fermentation tank, and the fermentation Comprising an air inlet pipe formed in the lower part of the tank and a fermentation product outlet pipe formed in the lower part of the fermentation tank,
An air bubble guide plate for temporarily suppressing the rise of air bubbles injected from the air injection pipe is formed on the side of the fermentation tank,
The fermentation tank has a rectangular cross section in the horizontal direction,
The bubble guide plate is a sludge treatment device, characterized in that consisting of a plurality of plates extending toward the center of the fermentation tank while inclined downward from both sides of the fermentation tank. delete The method of claim 1,
The air bubble guide plate is a sludge treatment apparatus, characterized in that the inclination is controlled so that the inclination can be converted to incline in the upward direction. 4. The method of claim 3,
Further comprising an upper stirrer formed on the upper portion of the fermentation tank,
The lower agitator moves the sludge treatment liquid in the upper direction of the fermentation tank, and the upper stirrer moves the sludge treatment liquid in the lower direction of the fermentation tank. 5. The method of claim 4,
While the lower agitator rotates, the bubble guide plate tilts downward, and while the upper stirrer rotates, the air bubble guide plate is controlled to tilt upward.

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