KR102580886B1 - Operation method and cultivation reactor for promoting granulation of Aerobic Granular Sludge - Google Patents

Abstract

The present invention relates to a culture tank for promoting granulation of aerobic granular sludge and a control method thereof. More specifically, it relates to a culture tank for promoting granulation of aerobic granular sludge having a granulation tank and an aeration tank, and a granulation tank for AGS formation. ; And an aeration tank that mixes the outflow water of the granulation tank and the inflow water to maintain the DO concentration above a set value, wherein the aeration tank includes a main body with a closed top, a blower and a diffuser for supplying air into the main body. and a second DO meter that measures DO concentration, and the granulation tank includes an inner cylinder into which effluent water from the aeration tank flows, a stirrer installed so that the impeller is located at the bottom of the inner cylinder, an outer cylinder spaced apart from the inner cylinder, and the inner cylinder and the outer cylinder. It relates to a culture tank for promoting aerobic granular sludge granulation, characterized by having a reaction tank as an interspace, and a reaction tank outlet provided outside the inner cylinder.

Description

Cultivation tank for promoting aerobic granular sludge granulation and its control method {Operation method and react cultivationor for promoting granulation of Aerobic Granular Sludge}

The present invention relates to a culture tank for promoting aerobic granular sludge granulation and a control method thereof. More specifically, it relates to a culture tank for promoting granulation of aerobic granular sludge containing exogenous acyl homoserine lactone and a method for controlling the same. This invention is the result of research with support from the Korea Environmental Industry & Technology Institute's water supply and sewerage innovation technology development funded by the Ministry of Environment.

Aerobic Granular Sludge (AGS) has been widely applied in the sewage and wastewater treatment field since its discovery in anaerobic sewage treatment systems in 1980. AGS is a microbial aggregate containing millions of microorganisms in 1g of aerobic granules. Compared to the existing activated sludge method, AGS can reduce operating costs by 20 to 25%, energy by 25 to 40%, and site area by 50 to 75%. This has possible advantages. However, despite these advantages, it may vary depending on the influent substrate composition, organic matter feed rate, hydrodynamic shear, abundance-deficiency period, influent supply strategy, dissolved oxygen concentration, reactor configuration, solids retention time, SBR reactor operation time, precipitation and butch exchange rate, etc. There is a big difference in the granulation of AGS.

Due to the diverse microbial population, differentiated operating conditions and reactor structures are required to select the desired species for AGS. For example, slow-growing organisms have a positive effect on the density and stability of AGS. Because the growth of nitrifying microorganisms is slow compared to the growth of heterotrophic microorganisms, the supply of organic matter must be limited, but the supply of organic matter is excessively limited. In this case, the consumption of extracellular polymer substances (EPS) increases and AGS granulation is limited.

In addition to slow-growing microorganisms, polyphosphate accumulating microorganisms (PAO) and glycogen accumulating microorganisms (GAO) are known to enhance the formation and stabilization of AGS, but GAO cannot accumulate phosphorus, which reduces the efficiency of phosphorus removal from the system, so PAO Since PAO and GAO consume the same substrate, volatile fatty acid (VFA) and undergo similar metabolism, PAO can become dominant only by lowering the C/N ratio and lowering the dissolved oxygen (DO) concentration. However, the C/N ratio concentration of the influent cannot be controlled, and lowering the DO causes the growth of filamentous bacteria and inhibits granulation, so it is virtually impossible to induce granulation and perform advanced treatment of sewage and wastewater in parallel.

In particular, among the driving factors contributing to granulation formation, hydrodynamic shear force is a factor that has a great influence on producing stabilized granules by promoting aerobic granulation, suppressing the growth of filamentous fungi, and preventing the enlargement of granules. Therefore, existing technologies require enormous operating costs by supplying excess air to promote granulation considering hydrodynamic shear force, and the reaction tank is manufactured and operated with a height/diameter ratio of 8 to 10 or more, making it suitable for large-scale treatment facilities. It has limitations that make it difficult to apply.

In addition, existing technologies mainly induce granulation in SBR reactors and are combined with advanced treatment. However, as mentioned above, granulation and advanced treatment are not compatible, so advanced operation technology is required and there are limits to granulation or compliance with discharge water quality. has.

Republic of Korea Patent No. 10-1272016 Republic of Korea Patent No. 10-1336988 Republic of Korea Patent No. 10-2103668 Republic of Korea Patent No. 10-2051259

Therefore, the present invention was developed to solve the above-described conventional problems. According to an embodiment of the present invention, an aerobic granular sludge can be used to promote the formation and granulation of aerobic granular sludge for sewage and wastewater treatment. The purpose is to provide a granulation promotion culture tank and a method for controlling it.

According to an embodiment of the present invention, it is composed of a granulation tank and an aeration tank, and the effluent of the granulation tank from which AGS and sludge are separated is introduced into the aeration tank, and then influent water and AHL (exogenous acyl homoserine lactone) are added as necessary, and the aeration tank is aerated. The DO concentration can be controlled and transported to the granulation tank, and the granulation tank promotes the granulation of AGS dominated by nitrifying microorganisms and PAO by supplying AHL and nutrients such as organic matter, nitrogen and phosphorus necessary for the growth of AGS. The purpose is to provide a culture tank and control method for promoting aerobic granular sludge granulation, which can promote AGS granulation with less energy by supplying pure hydrodynamic shear force using a stirring facility that does not contact AGS and sludge. .

According to an embodiment of the present invention, a method of determining the end point of granulation by calculating the oxygen consumption rate (OUR) using the DO concentration in the granulation tank is applied to promote the formation of granulation while reducing the amount of air supply. This reduces maintenance costs, can be applied to large sewage treatment plants due to the low height/diameter ratio of the reaction tank, and promotes aerobic granular sludge granulation, which can improve maintenance by introducing a rational and scientific operation system. The purpose is to provide a culture tank and a control method for the same.

Meanwhile, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly apparent to those skilled in the art from the description below. It will be understandable.

The first object of the present invention is a culture tank for promoting aerobic granular sludge (AGS) granulation having a granulation tank and an aeration tank, including a granulation tank for AGS formation; And an aeration tank that mixes the effluent of the granulation tank and the influent sewage water to maintain the DO concentration above a set value, wherein the aeration tank includes a main body with a closed top, and a blower for supplying air into the main body. It has an air diffuser and a second DO meter that measures DO concentration, and the granulation tank includes an inner cylinder into which effluent water from the aeration tank flows, an agitator installed so that an impeller is located at the bottom of the inner cylinder, an outer cylinder spaced apart from the inner cylinder, and It can be achieved as a culture tank for promoting granulation of aerobic granular sludge, characterized by having a reaction tank that is a space between the inner cylinder and the outer cylinder, and a reaction tank outlet provided on the outside of the inner cylinder.

And, in the aeration tank, the effluent of the granulation tank flows in, exogenous acyl homoserine lactone (AHL) is mixed with the wastewater influent, and a separation member is provided to separate the space where the granulation tank effluent and inflow water and AHL are mixed. Includes ;, and the control unit may be characterized in that it controls the DO concentration in the aeration tank by controlling the blower based on the DO value measured by the second DO meter.

In addition, it may be characterized by including a granulation tank transfer pipe that flows the effluent from the aeration tank into the inner cylinder, a transfer pump provided on one side of the granulation tank transfer pipe to provide power for transfer, and a flow meter.

And it includes a diamond-shaped portion whose diameter is expanded at the position where the impeller is installed on the lower outlet side of the inner cylinder, and a baffle plate is installed to distribute the effluent to the inner cylinder outlet at the lower end of the diamond-shaped portion and allow it to flow into the reaction tank. It can be characterized as:

In addition, the lower end of the outer cylinder has a hopper shape whose diameter gradually decreases toward the bottom, and the cross section between the inclined surface of the hopper and the reduced diameter portion of the diamond-shaped portion is larger than the cross section of the outlet portion of the inner cylinder, so that AGS does not flow into the inner cylinder and the reaction tank. It may be characterized by preventing AGS from settling in the lower hopper.

And a first DO meter for measuring the DO value in the reaction tank, an MLSS meter for measuring the MLSS concentration in the reaction tank, and a sludge interface meter for measuring the sludge interfacial height in the reaction tank, and the MLSS concentration value measured by the MLSS meter. And, the injection amount and injection timing of the influent water and AHL may be controlled based on the sedimentation property of the sludge.

In addition, the reaction tank outlet is equipped with an inclined plate to minimize the inflow of AGS and sludge, and includes a weir outlet where a weir is installed to minimize the outflow of filamentous bacteria and fine flocs from the effluent discharged from the reaction tank outlet. The granulating tank effluent that has passed through the weir outlet unit may be characterized in that it flows into the inlet side of the aeration tank through an outflow passage.

In addition, the water flow in the reaction tank has the fastest flow rate at the point where it flows out through the inner tube outlet, and the outflow water passing through the inner tube outlet and moving upward along the side of the lower hopper of the reaction tank reaches the maximum diameter part of the diamond-shaped part. Afterwards, the flow rate decreases, and the flow rate along the outer pipe is relatively fast, and in the area close to the inner pipe, a vortex is formed in contact with the downward flow in the reaction tank, reducing the flow rate, and aerobic granulation is promoted by the hydrodynamic shear force caused by the vortex. It can be characterized by inhibiting the growth of filamentous fungi and preventing the enlargement of granules.

The second object of the present invention is a control method of a culture tank for promoting granulation of aerobic granular sludge according to the first object mentioned above, wherein the DO value of the aeration tank is measured through a second DO meter, and the DO value of the aeration tank is set as the first target. The first step of reaching a value; A second step in which the DO value of the granulating tank is measured through a first DO meter, and the DO value of the granulating tank reaches a set second target value; A third stage in which oxygen consumption exceeds the target value; A fourth step in which the MLSS concentration in the granulation tank is measured using an MLSS meter, and the MLSS concentration in the granulation tank reaches the target value; A fifth step of stopping the stirring of the stirrer and measuring the sludge interfacial height through a sludge interfacial meter; And when the sludge interface height reaches the target value, a sixth step of operating the control equipment of the AGS harvest transfer path; It can be achieved as a control method of a culture tank for promoting granulation of aerobic granular sludge, comprising a. .

And in the first step, the blower is controlled to increase the blowing flow rate until the first target value is reached, and in the second step, the stirrer and the blower are controlled until the second target value is reached to increase the stirring speed and blowing speed. The flow rate is increased, and in the fourth step, the injection amount and injection time of the influent water and AHL are determined based on the MLSS concentration value measured by the MLSS meter and the sedimentation property of the sludge, and the MLSS concentration value is a target value. In the fifth step, the stirring speed and blowing flow rate are increased by controlling the stirrer and blower until the interface height reaches the target value. can do.

According to the aerobic granular sludge granulation promotion culture tank and the method for controlling the same according to an embodiment of the present invention, it has the effect of promoting the formation and granulation of aerobic granular sludge for sewage and wastewater treatment.

According to the culture tank and its control method for promoting aerobic granular sludge granulation according to an embodiment of the present invention, it is composed of a granulation tank and an aeration tank, and the effluent of the granulation tank from which AGS and sludge are separated is introduced into the aeration tank and then aerated as needed. Accordingly, inflow water and AHL (exogenous acyl homoserine lactone) can be added and the DO concentration in the aeration tank can be controlled to transfer it to the granulation tank. In the granulation tank, nutrients such as organic matter, nitrogen, and phosphorus necessary for the growth of AGS and AHL are supplied. It promotes AGS granulation dominated by nitrifying microorganisms and PAO, and has the effect of promoting AGS granulation with less energy by supplying pure hydrodynamic shear force using a stirring facility that does not come into contact with AGS and sludge.

And according to the culture tank and its control method for promoting aerobic granular sludge granulation according to an embodiment of the present invention, the end point of granulation can be determined by calculating the oxygen consumption rate (OUR) using the DO concentration in the granulation tank. By applying existing methods, the formation of granules is promoted, while maintenance costs are reduced by reducing the amount of air supply. The height/diameter ratio of the reaction tank is low, so it can be applied to large sewage treatment plants, and the introduction of a rational and scientific operation system This has the advantage of improving maintenance.

Meanwhile, the effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention along with the detailed description of the invention, so the present invention is limited only to the matters described in such drawings. It should not be interpreted as such.
1 is a schematic cross-sectional view of a culture tank according to a first embodiment of the present invention;
Figure 2 is a schematic cross-sectional view of a culture tank installed with a settling basin according to a second embodiment of the present invention;
3 is a schematic top plan view of the culture tank according to the first embodiment of the present invention;
4 is a schematic top plan view of a culture tank according to a second embodiment of the present invention;
Figure 5 is a schematic diagram of water flow movement in a granulation tank according to an embodiment of the present invention;
Figure 6 is a flowchart of a culture tank operation control method according to an embodiment of the present invention;
Figure 7 is a schematic diagram of a batch reactor showing N-acyl homoserine lactone (AHL) added to each according to an experimental example of the present invention;
Figure 8 is a graph of EPS content change according to AHL type in an experimental example of the present invention;
Figure 9 shows EEM fluorescence spectra (a) example, (b) LB-EPS (c) TB-EPS, according to an experimental example of the present invention.
Figure 10 is a graph comparing the fluorescence intensity of (a) LB-EPS (B) TB-EPS when four types of AHL are added to the control group according to an experimental example of the present invention;
Figure 11 shows the effect of AHL on the relative hydrophobicity of sludge according to an experimental example of the present invention;
Figure 12 is a CLSM image of a biofilm on a membrane according to an experimental example of the present invention,
Figure 13 shows particle size distribution and corresponding sludge image according to an experimental example of the present invention;
Figure 14 is a graph of changes in MLSS, VS/TS, and SVI according to AHL type in an experimental example of the present invention;
Figure 15 is a schematic diagram of a continuous reactor according to an experimental example of the present invention;
Figure 16a is a graph comparing the COD removal efficiency between the case where C8-CHL was injected according to an experimental example of the present invention (hereinafter referred to as W/AHL) and the case where C8-CHL was not injected as a control (hereinafter referred to as W/O AHL);
Figure 16b is a graph comparing the total nitrogen (TN) removal efficiency of W/AHL and W/O AHL;
Figure 16c is a graph comparing the total phosphorus (TP) removal efficiency of W/AHL and W/O AHL;
Figure 17 is a graph of LB-EPS content change for W/O AHL (a) and W/AHL (b);
Figure 18 is a graph of TB-EPS content change for W/O AHL (a) and W/AHL (b);
Figure 19 is an average particle size comparison graph for W/O AHL (a) and W/AHL (b);
Figure 20 shows images for W/O AHL (a) and W/AHL (b).

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments related to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete and so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art.

In this specification, when an element is referred to as being on another element, it means that it may be formed directly on the other element or that a third element may be interposed between them. Also, in the drawings, the thickness of components is exaggerated for effective explanation of technical content.

Embodiments described herein will be explained with reference to cross-sectional views and/or plan views, which are ideal illustrations of the present invention. In the drawings, the thicknesses of films and regions are exaggerated for effective explanation of technical content. Therefore, the shape of the illustration may be changed depending on manufacturing technology and/or tolerance. Accordingly, embodiments of the present invention are not limited to the specific form shown, but also include changes in form produced according to the manufacturing process. For example, an area shown as a right angle may be rounded or have a shape with a predetermined curvature. Accordingly, the regions illustrated in the drawings have properties, and the shapes of the regions illustrated in the drawings are intended to illustrate a specific shape of the region of the device and are not intended to limit the scope of the invention. In various embodiments of the present specification, terms such as first and second are used to describe various components, but these components should not be limited by these terms. These terms are merely used to distinguish one component from another. Embodiments described and illustrated herein also include complementary embodiments thereof.

The terminology used herein is for describing embodiments and is not intended to limit the invention. As used herein, singular forms also include plural forms, unless specifically stated otherwise in the context. As used in the specification, 'comprises' and/or 'comprising' does not exclude the presence or addition of one or more other elements.

In describing specific embodiments below, various specific details have been written to explain the invention in more detail and to aid understanding. However, a reader with sufficient knowledge in the field to understand the present invention can recognize that it can be used without these various specific details. In some cases, it is mentioned in advance that when describing the invention, parts that are commonly known but are not significantly related to the invention are not described in order to prevent confusion without any reason in explaining the invention.

Hereinafter, the structure, function, and control method of a culture tank for promoting aerobic granular sludge granulation according to an embodiment of the present invention will be described.

Figure 1 shows a schematic cross-sectional view of a culture tank according to a first embodiment of the present invention. And Figure 2 shows a top plan schematic diagram of the culture tank according to the first embodiment of the present invention.

As shown in FIG. 1, the culture tank for promoting aerobic granular sludge granulation according to the first embodiment of the present invention includes a granulation tank 200 for AGS formation, effluent from the granulation tank 200, and wastewater influent. and an aeration tank (100) that maintains the DO concentration above 2 mg/L by mixing AHL (exogenous acyl homoserine lactone).

The granulation tank 200 includes a stirrer 240, a first DO meter 270 including a DO sensor, an MLSS meter 271, and a sludge interface meter 272.

The aeration tank 100 includes a blower 121, a blower flow meter 122, an air diffuser 120, etc.

In addition, between the granulation tank 200 and the aeration tank 100, a granulation tank transfer pipe 20, a transfer pump 30, and a transfer flow meter 40 are included.

The aeration tank 100 mixes the effluent from the granulation tank 200, the influent sewage and wastewater, and AHL, induces agitation through aeration using a blower 121 without a separate stirrer, and uses a 2DO meter (140) including a DO sensor. )) is used to control the DO concentration in the aeration tank (100).

That is, the aeration tank 100 includes a main body 110 with a closed top, a blower 121 and an air diffuser 120 for supplying air into the main body 110, and a 2DO meter that measures DO concentration ( 140).

In addition, the granulating tank 200 includes an inner cylinder 210 into which the effluent water from the aeration tank 100 flows, an agitator 240 installed so that the impeller 242 is located at the inner bottom of the inner cylinder 210, and an inner cylinder 210 that is spaced apart from each other. It is composed of an outer cylinder 251, a reaction tank 250 that is a space between the inner cylinder 210 and the outer cylinder 251, and a reaction tank outlet 260 provided outside the inner cylinder 210. The control unit controls the DO concentration in the aeration tank 100 by controlling the blower 121 based on the DO value measured by the second DO meter 140.

In addition, the aeration tank 100 includes a separation member 111 provided to separate the space where the granulation tank effluent and inflow water and AHL are mixed.

That is, the aeration tank 100 includes a separate space where the granulation tank effluent, inflow water, and AHL can be mixed using the internal partition wall 111, etc., and the upper part is closed to minimize contact with the atmosphere. do. The separate space where the granulation tank effluent, inflow water, and AHL can be mixed is to prevent immediate outflow of the mixed water, and is characterized by both complete spatial separation or zone separation using the partition wall 111. . In addition, the upper part of the aeration tank 100 is installed to minimize penetration of microorganisms present in the atmosphere or contact with other microorganisms present in the treatment facility.

The granulation tank effluent flows into the aeration tank 100, and the DO concentration is measured in real time using the second DO meter 140 to maintain the DO concentration at 2 mg/L or more. At this time, the DO concentration is controlled by adjusting the air supply amount using the blower 121. As will be explained later, the injection amount and injection timing of wastewater influent and AHL are controlled according to the MLSS concentration of the granulation tank 200 and the sedimentation property of the sludge.

The granulating tank 200 includes a propeller-type agitator 240 that moves the water flow in the downward direction of the granulating tank 200, an inner cylinder 210 into which the effluent of the aeration tank 100 flows, and a granulating tank 200 in the inner cylinder 210. Inside, a rectifying plate 230 that evenly distributes and supplies the effluent from the aeration tank 100, a reaction tank 250 that induces AGS formation, an outlet portion 260 having an inclined plate 261 through which AGS is separated and discharged, and a weir. It is configured to include a weir outlet 262 and an outlet passage 263 connected to the aeration tank 100.

Also, as mentioned above, the granulation tank 200 includes a first DO meter 270 including a DO sensor, an MLSS meter 271, a sludge interface meter 272, and a transfer path 290 for harvesting or transferring AGS. It is characterized by including equipment (valve, pump, etc.) 291 that controls it.

A propeller-type agitator 240 whose rotation speed is controllable is installed in the inner cylinder 210 of the granulating tank 200. The purpose of the propeller-type stirrer 240 is to move the mixing and water flow in the inner tube 210 downward and to prevent AGS present in the reaction tank 250 from entering the inner tube 210.

To this end, the inner cylinder 210 is configured to include a diamond-shaped portion 220 at the position of the impeller 242 of the propeller stirrer 240. In particular, the outlet portion of the inner cylinder 210 is made as small as possible to minimize the inflow of the AGS into the inner cylinder 210, and a flow plate 230 is installed to enable the flow to flow out as evenly as possible. If the outlet portion of the inner tube 210 is small, the flow rate is inversely proportional to the outlet cross section, so the flow rate increases, and the inflow into the inner tube 210 is minimized. The faster the flow rate, the faster the influent water discharged from the inner tube 210 moves upward along the side of the lower hopper 252 of the reaction tank 250, thereby preventing AGS from settling in the lower part of the reaction tank 250.

In order to prevent AGS from flowing into the inner cylinder 210, the cross section between the reduced diameter portion 222 of the diamond-shaped portion 220 and the inclined surface of the lower hopper 252 of the reaction tank must be slightly larger than the cross section of the outlet portion of the inner cylinder 210. do.

When the effluent moving upward reaches point A(3), the cross-section of the reaction tank 250 increases and the flow rate decreases significantly. However, the flow rate is relatively fast on the inner surface of the outer cylinder 251 of the reaction tank 250, and the inner cylinder (250) As it moves to the area adjacent to 210), a vortex is formed due to descent within the reaction tank 250 and the flow rate decreases.

Therefore, the outlet portion 260 is installed near the inner cylinder 210 with a relatively slow flow rate. Since AGS and sludge flows into the outlet 260, an inclined plate 261 is installed to induce precipitation of AGS and sludge to minimize outflow.

However, since filamentous bacteria and fine flocs may be present in the effluent flowing out through the outlet 260, it is characterized by having a weir outlet 262 in which a weir is installed to minimize the inflow of these into the aeration tank 100.

Due to the structure of the outflow section 260 having the inclined plate 261 and the wear outflow section 263 where the wear is installed, the outflow of filamentous bacteria and fine flocs is minimized, and even if filamentous bacteria are introduced into the aeration tank 100, the aeration tank 100 Because they are killed in the aeration tank (100) due to the high DO concentration, it is possible to prevent a decrease in granulation stability caused by filamentous bacteria, and the step of removing filamentous bacteria through sedimentation at regular time intervals can be minimized, thereby reducing anaerobic activity in the reaction tank (250). Burning can be minimized and the operating time of the reaction tank 250 can be maximized.

And, a first DO meter 270, an MLSS meter 271, and a sludge interface meter 272 are installed in the reaction tank 250. The oxygen consumption (mg O ₂ /L·hr) is calculated using the DO concentration measured in real time in the reaction tank 250 using the first DO meter 270.

Then, the OUR is periodically calculated using the MLSS measurements, and the timing and amount of influent and AHL input, as well as the DO concentration in the aeration tank, are determined. In addition, the sludge interface meter 272 evaluates the sedimentation of AGS by stopping the inflow and stirring at a certain period when the target MLSS concentration is reached, and when the predefined target value is reached, the AGS is harvested or transported to the main treatment facility.

Figure 3 shows a schematic cross-sectional view of a culture tank installed with a settling basin according to a second embodiment of the present invention. And Figure 4 shows a top plan schematic diagram of the culture tank according to the second embodiment of the present invention.

In the second embodiment of the present invention, as shown in Figures 3 and 4, it can be seen that a separate settling tank 131 can be installed to remove AGS and sludge present in the granulation tank effluent. Even if the outflow of filamentous bacteria or fine flocs is minimized, sludge outflow may occur, and if sludge outflows for a long period of time, it may flow into the aeration tank and be cultured in the aeration tank 100. To prevent this, a separate settling tank ( 131) can be installed.

Figure 5 shows a schematic diagram of water flow movement in a granulation tank according to an embodiment of the present invention. As mentioned above, a propeller-type agitator 240 whose rotation speed is controllable is installed in the inner cylinder 210 of the granulating tank 200 to move the water flow in the inner cylinder 210 in the downward direction.

In addition, due to the baffle plate 230 installed at the outlet of the inner tube 210, the water flowing out of the inner tube flows out equally in all directions, and the flow speed at point A(1) is characterized by the fastest flow speed at all points. do. In particular, the outlet portion of the inner cylinder 210 includes a diamond-shaped portion 220 at the position of the impeller 242 of the propeller agitator 240, so that the cross section [A(2)] between it and the inclined surface of the lower hopper 252 of the reaction tank is Since it is slightly larger than the cross section of the outlet of the inner cylinder 210 [A(1)], AGS does not flow into the inner cylinder 210 and prevents AGS from being deposited in the lower hopper 252 of the reactor.

And when the effluent moving upward along the side of the lower hopper 252 of the reaction tank reaches point A (3), the cross-section of the reaction tank 250 increases and the flow rate decreases significantly, but the outer cylinder 251 side of the reaction tank 250 [A(4)] In the area [A(7)] where the flow rate is relatively highest and adjacent to the inner tube 210, vortices are formed in contact with the downward flow within the reaction tank 250 and the flow rate decreases. In this area [A(7)], the hydrodynamic shear force is the highest within the granulation tank 200, and the high shear force promotes aerobic granulation, inhibits the growth of filamentous fungi, and prevents the granulation from becoming large.

When the inflow water rising along the outer cylinder (251) of the reaction tank reaches point A (5), the upper part is blocked because it is the weir outlet (262), so it moves along the upper surface, and near the inner cylinder (210) [A (6)]. It goes down. At this time, as it comes into contact with the inflow water rising through A(3), a vortex is formed and is affected by hydrodynamic shear force. When the inflow water moving downward reaches the area A (7), the AGS and sludge settle in the expansion part 221 of the diamond-shaped part 220 of the inner tube 210 due to the diamond-shaped part 220 of the inner tube, but the slope is also and moves downward along the ramp of the diamond-shaped portion 200 due to the downward flow rate occurring at the top. As described above, the AGS and sludge that moved to the bottom come into contact with the influent water that passed through point A(2) in section A(3), are mixed, and are exposed to high shear force due to eddy currents, thereby promoting granulation.

Since outflow water containing AGS flows into the inlet part [A(8)] of the outlet part 260, an inclined plate 261 is installed to prevent the outflow of AGS.

Figure 6 shows a flowchart of a culture tank operation control method according to an embodiment of the present invention.

First, the 2DO value of the aeration tank is measured through the 2DO measuring device to determine whether the 2DO value has reached the set first target value (S10). If the first target value is not reached, the blower 121 is controlled to increase the blowing flow rate until the first target value is reached (S11).

And when the first target value is reached, the DO value of the granulation tank 200 is measured through the first DO meter 270, and it is determined whether the DO value of the granulation tank 200 has reached the set second target value ( S20). If it is not reached, the stirring speed and blowing flow rate are increased by controlling the stirrer 240 and the blower 121 until the second target value is reached (S21, S22).

The DO concentration in the aeration tank 100 is preferentially controlled by the first DO meter 270 installed at the granulation tank outlet 260. The DO concentration of the effluent cannot be defined because it varies depending on the state and size of AGS, cultivation period, influent water quality, etc., but should generally be maintained above DO 0.1 mg/L.

The DO concentration of the aeration tank 100 measured by the 2nd DO meter 140 and the DO concentration of the granulation tank 200 measured by the 1st DO meter 270 are measured in real time and then introduced in consideration of the residence time of the granulation tank. Calculate the oxygen consumption (mg O ₂ /L·hr) by substituting the DO concentration in the aeration tank (measured by the first DO meter) at the time of this point into Equation 1 below (S30).

[Equation 1]

Oxygen consumption (mg O ₂ /L·hr) = (DO(2) (mg/L) - DO(1)(mg/L)) / (HRT(hr) × reactor volume(L))

If the oxygen consumption exceeds the target value, it is determined whether the MLSS concentration has reached the target (S40). If the MLSS concentration is below the target value, the substrate is insufficient, so the stirring speed of the granulation tank 200 is increased by a predefined ratio and (S41), and operates by inputting a fixed amount of inflow water and AHL (S42).

When the MLSS concentration reaches the target value, stirring is stopped, the sludge is allowed to settle, and the sludge interface height is measured to determine whether the target has been reached (S50). At this time, if the sludge interface height is below the target value, granulation formation is limited, so the stirring speed and aeration tank blowing flow rate are increased (S51, S52).

Afterwards, when all target values are reached, the automated equipment (valve or pump) 291 installed in the transfer path 290 of the granulation tank is operated to harvest or transfer AGS.

Hereinafter, a specific experimental example of exogenous acyl homoserine lactone (AHL) added together with the influent flowing through the inlet 130 of the aeration tank 100 according to an embodiment of the present invention will be described. Exogenous acyl homoserine lactone (AHL) functions as a granulation promoter.

The aerobic granular sludge granulation accelerator containing exogenous acyl homoserine lactone (AHL) according to the present invention promotes the granulation of aerobic granular sludge.

N-acyl-homoserine lactone (AHL) is a small diffusible signaling molecule secreted by Gram-negative bacteria and has a molecular structure suitable for QS expression. Addition of AHL signaling molecules increases biomass growth rate, microbial activity, and nitrifying biofilm formation. EPS synthesis can be greatly promoted by adding exogenous AHL according to an embodiment of the present invention. In particular, exogenous C6-HSL and C8-HSL can not only increase nitrogen removal efficiency but also have significant effects on EPS and microbial community production. Exogenous C10-HSL and C8-HSL promote anaerobic granule formation.

In other words, AGS formation and granulation are promoted through quorum sensing (QS) expression of the AHL signaling molecule.

The AHL signal molecule according to the present invention may be at least one of C6-HSL, C8-HSL, C10-HSL, and C12-HSL. In particular, the AHL signal molecule according to the present invention is C8-HSL.

The biofilm formation process consists of five stages: initial attachment, irreversible attachment by EPS secretion, proliferation, maturation, and dispersal. Exogenous AHL according to embodiments of the present invention can accelerate the initial granulation process. Exogenous addition of AHL can accelerate biofilm formation and shorten the onset delay period by approximately 50%.

The aerobic granular sludge granulation accelerator containing exogenous acyl homoserine lactone (AHL) according to the present invention promotes the secretion of extracellular polymer substances (EPS).

In addition, the aerobic granular sludge granulation accelerator containing exogenous acyl homoserine lactone (AHL) according to the present invention increases granule size, increases biomass content, increases relative hydrophobicity, improves sludge solidity, and promotes biofilm formation.

Below, when applying the aerobic granular sludge granulation accelerator containing exogenous acyl homoserine lactone (AHL) according to the present invention, examples, experimental examples, and result data on sludge characteristics, particle size, EPS, and biofilm formation are provided. Let me explain.

In an example of the present invention, the effect of AHL-mediated QS on aerobic granulation was tested using several types of AHL in a batch manner. This is to determine the most suitable AHL type for the AGS system. In an experimental example of the present invention, sludge characteristics, particle size, EPS, and biofilm formation were tested.

In an experimental example of the present invention, a batch experiment was performed to investigate the type of AHL signal molecule most suitable for the granulation process and AGS system.

Figure 7 shows a schematic diagram of a batch reactor showing N-acyl homoserine lactone (AHL) added to each according to an experimental example of the present invention.

As shown in Figure 7, activated sludge (300 mL) and synthetic wastewater (300 mL) were mixed in a 1L reactor. One of the five reactors without addition of AHL was used as a control. The remaining four reactors contained 5 μM of N-Hexanoyl-L-homoserine lactone (C6-HSL), N-Octanoyl-L-homoserine lactone (C8-HSL), N-Decanoyl-L-homoserine lactone (C10-HSL), N-Dodecanoyl-L-homoserine lactone (C12-HSL) was injected.

The sludge seeding sludge returned from the Jungnang secondary purifier was used at a sewage treatment plant in Seoul. The TSS and VSS of the sludge were 3,260 mg/L and 2,658 mg/L, respectively. Synthetic wastewater was prepared by simulating the lateral flow of a sewage treatment plant.

The composition is as follows: COD 2,480 mg/L (sodium acetate), TN 86.03 mg/L (NH ₄ Cl), TP 24.57 mg/L (K ₂ HPO ₄ and KH ₂ PO ₄ ). The reactor was mixed at 90 rpm using a stirrer, and the temperature was maintained at 25 ± 2°C. Air was supplied at a rate of 200 mL/min through an air diffuser to maintain aerobic conditions.

Below, the analysis method in the experimental example of the present invention and the results according to the analysis method will be described.

Analysis of batch reactor parameters including mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), and sludge volume index (SVI) were performed according to standard methods (23rd edition). To investigate the morphology of the sludge, an optical microscope (BX51, Olympus Co., Japan) and a field emission scanning electron microscope (FE-SEM, SU8010, Hitachi Ltd., Japan) were used. The particle size distribution of the granules was measured using a particle size analyzer (Malvern Mastersizer 2000, Malvern Panalytical Ltd., UK).

EPS extraction used heat extraction, which is the most effective extraction method, and used a modified existing heat extraction method. Sludge (25 mL) in the reactor was sampled and centrifuged at 4,000 g for 5 minutes. The supernatant was discarded, and the remaining solid was resuspended in phosphate-buffered saline at 70°C, mixed for 1 minute, and centrifuged (4,000 g, 10 minutes) to measure loosely bound EPS (LB-EPS) in the supernatant. The solid remaining after extraction was resuspended in phosphate-buffered saline at 60°C, mixed for 1 minute, and then reacted in a 60°C water bath for 30 minutes. The supernatant was centrifuged at 4,000g for 15 minutes and then filtered through a 0.45μm filter to measure TB -EPS (tightly-bound EPS).

EPS extracted in the experimental example of the present invention was quantified as the sum of its main components, protein (PN) and polysaccharide (PS). Proteins were analyzed using the Bio-Rad protein assay based on the Bradford dye binding method. For protein quantification, a standard curve was created using a 2 mg/mL bovine serum albumin stock solution. 0.5 mL of sample and 0.5 mL of protein dye (Bio-Rad, USA) were placed in a micro cuvette, reacted for 15 minutes, and the absorbance was measured at 595 nm using a UV/VIS spectrometer (OPTIZEN POP, Mecasys Co.). PS was analyzed using a TOC analyzer (Multi N/C-3100, Analytik Jena AG, Germany).

To investigate the effect of AHL on organic composition, the extracted EPS solution was analyzed using a fluorescence excitation-emission matrix (F-EEM, RF-5301 spectrofluorometer). The fluorescence properties of organic materials were scanned using an arc lamp at excitation wavelengths of 220–400 nm (10 nm steps) and emission wavelengths of 280–600 nm (1 nm steps).

And in the experimental example of the present invention, relative hydrophobicity (RH) was measured by partially modifying the hydrocarbon-hexane extraction method. A 15 mL sample was mixed with an equal volume of n-hexane in a separatory funnel for 10 min. After 30 minutes, when the two phases were completely separated, the water phase was moved and the absorbance was measured at 600 nm. RH (%) was calculated according to Equation 2 using the absorbance before and after n-hexane treatment.

[Equation 2]

RH(%) = (1-A ₀ /A) × 100

Here, A ₀ is OD600 before n-hexane treatment, and A is OD600 after n-hexane treatment.

In addition, for biofilm analysis according to the experimental example of the present invention The membrane was cut into 1.5 cm × 1.5 cm pieces, fixed in a batch reactor, and operated with sludge for 24 hours. Membrane fragments with attached microorganisms were washed twice with 0.9% NaCl solution and stained with LIVE/DEAD BacLight Bacterial Viability Kit (Molecular Probes, Eugene, Oregon, USA) containing SYTO9 and propidium iodide (PI).

SYTO9 is a green fluorescent dye that can penetrate both living and dead cells, while PI is a red fluorescent dye that can only penetrate dying or dead cells with damaged cell membranes. For biofilm staining, 3 μL SYTO9 and 3 μL PI solutions were mixed with 1 mL distilled water, and 200 μL of the mixture was pipetted to cover the entire membrane surface.

The Petri dish containing the membrane was covered with aluminum foil and left in the dark for 30 minutes, then washed carefully with distilled water to remove any excess stains. The membrane was mounted on a glass slide with a cover. A confocal laser scanning microscope (CLSM, LSM 810, Carl Zeiss, Germany) was used to investigate and image the thickness, shape, and distribution of biofilms attached to the membrane surface. All images were analyzed using an image analysis program (Zen software, Carl Zeiss Co., Germany), and CLSM images of biofilms formed on the membrane surface were quantified using COMSTAT image analysis software.

The resulting data according to the experimental example of the present invention will now be described.

Depending on the relationship between EPS and cells, EPS is composed of two layers: TB-EPS and LB-EPS. TB-EPS forms the inner layer surrounding the microbial cells, and LB-EPS forms the outer layer covering TB-EPS. The composition of EPS has different effects on sludge properties, and the addition of exogenous AHL not only changes the distribution of EPS but also affects its functional groups. In the present invention, EPS is divided into TB-EPS and LB-EPS.

Figure 8 shows a graph of changes in EPS content according to AHL type in an experimental example of the present invention (PN: protein, PS: polysaccharide, LB: loosely bound, TN: tightly bound)

It can be seen that different types of AHL signal molecules have slightly different effects on EPS content. TB-EPS was found to be 18.49 mg/g VSS and 18.68 mg/g VSS in reactors with C8-HSL and C12-HSL, respectively. Unlike -HSL and C10-HSL, it was higher than the control group (17.91 mg/g VSS).

LB-EPS significantly increased compared to TB-EPS, and all reactors to which AHL signal molecules were added showed increased LB-EPS compared to the control group. This may be because the shear resistance of LB-EPS is lower than that of TB-EPS.

Overall, C8-HSL was most effective in increasing EPS content. Among AHL types, TB-EPS and LB-EPS in the reactor containing C8-HSL increased by 3.15% and 53.76% to 18.49 and 74.07 mg/g VSS, respectively, compared to the control group. In other words, we found that adding C8-HSL increased the EPS content.

Sludge flocculation and granulation can be affected by changing surface properties such as surface charge and hydrophobicity. Among its components, PN plays an important role in crosslinking because it has a better affinity for cations than other components. Synthesis of PS, another component, may affect cell adhesion ability and help in the formation and stability of microbial aggregates.

Although LB-PS accounts for a larger proportion of total EPS, the addition of AHL appears to have a greater impact on the increase in LB-PN, with LB-PN increasing by up to 2.41 times. Polysaccharides, especially through AHL signaling molecules, were observed to have a significant effect on EPS increase. AHL signaling molecules affect the early stages of granule formation, resulting in increased biomass concentration, hydrophobicity, and sedimentation.

The composition of EPS was analyzed to investigate the effect of adding AHL signaling molecules to the organic matter composition of EPS. Figure 9 shows EEM fluorescence spectra according to an experimental example of the present invention (a) example, (b) LB-EPS, and (c) TB-EPS. Figure 10 shows a graph comparing the fluorescence intensity of (a) LB-EPS (B) TB-EPS when four AHLs are added to the control group according to an experimental example of the present invention.

It can be seen that in the reactor containing C8-HSL, peaks T1 and T2 corresponding to protein-like substances are the highest among the LB-EPS components. Unlike other AHL additions, peaks B1 and B2 also appeared prominent. This result corresponds to the protein content of EPS (Figure 8).

In other words, AHL signaling molecules promoted the secretion of protein-like substances, and the addition of C8-HSL had the greatest effect. As shown in Figures 9b and 9c, the peaks T1 and T2 of TB-EPS were highest in the reactor with C8-HSL. In the reactor where C8-HSL, C10-HSL, and C12-HSL were added, the fluorescence intensity of peaks A and C was high, which corresponds to substances similar to fulvic acid and humic acid in EPS (Figure 10). Protein-like substances are beneficial to the formation and stability of granular sludge, while humic and fulvic acid-like substances have the potential to worsen granulation. Additionally, humic acid-like organic substances are mainly produced by cell death and decomposition of organisms, and their accumulation may not be beneficial to the aggregation of microorganisms.

It can be seen that the addition of AHL signaling molecules changed the composition of EPS and could have a positive effect on granulation.

Additionally, in an experimental example of the present invention, it was found that C8-HSL had the greatest effect on both EPS and aromatic protein-like substances containing tryptophan. This is because short-chain AHLs may be more favorable for granule formation than long-chain AHLs, and tryptophan and aromatic protein-like substances are the main substances for EPS formation in the initial sludge. This suggests that the addition of C8-HSL may contribute to granule formation.

Below, the influence of AHL on relative hydrophobicity and biofilm formation will be described based on the result data for the experimental examples of the present invention. Change in relative hydrophobicity of sludge is one of the main characteristics of biomass forming biofilms. Increased cell surface hydrophobicity can be considered a force that promotes cell-cell interactions and causes granulation.

Figure 11 shows the effect of AHL on the relative hydrophobicity of sludge according to an experimental example of the present invention. As shown in Figure 11, all types of AHL signaling molecules increased the RH value of sludge flocs regardless of type.

The AHL that showed the highest increase in hydrophobicity was C8-HSL, with an RH value of 16.36% and n RH value of 25.00% in the control reactor, an increase of approximately 1.53 times in the reactor containing C8-HSL. The type of AHL that had the least effect on the increase in RH value was C10-HSL, with an RH value of 20.00%, which was about 1.22 times higher than the control reactor in which AHL was not added.

As the hydrophobicity of sludge floc increases, bioflocculation can increase and adhesion can be improved. Therefore, the higher the RH value, the better the cohesive properties. The relatively low surface charge and high hydrophobicity promote the aggregation of microorganisms. Figure 11 shows that the sludge floc formed by applying AHL has excellent hydrophobicity and can form granular sludge with larger size and denser structure.

In the experimental examples of the present invention, biofilms were observed using CLSM image analysis and information on structure, morphology, and biomass was obtained. Because the structure of the biofilm was not homogeneously distributed, the entire central part of the membrane was analyzed. Figure 12 shows a CLSM image of the biofilm on the membrane. The stronger the fluorescence of the microorganism, the brighter the green fluorescence appears. Most cells appear to exhibit green fluorescence, indicating that they are alive due to their high metabolism. However, in the control reactor where AHL was not added, biofilm was not formed well and was hardly observed in the image.

The effect of AHL was compared by quantifying biofilm volume and thickness using CLSM images. The biomass volume of the membrane operated for 24 hours was 7.82 ± 6.17 μm ³ /μm ² and 6.99 ± 10.22 μm ³ /μm ² for C8-HSL and C12-HSL, respectively, which was greater than 3.58 ± 8.72 μm ³ /μm ² . The average biomass thickness of C8-HSL was also highest in the reactor at 15.31 ± 12.96 μm, followed by C12-HSL at 14.45 ± 10.69 μm.

These results suggest that addition of AHL increases the thickness of biofilm and biomass. This is because AHL promotes EPS secretion, improving bacterial attachment and promoting 3D biofilm construction. The addition of QS-related substances, such as AHL, can contribute to the significant changes in EPS and biofilm that can be achieved through QS signaling. Therefore, it can be seen that the addition of AHL can promote biofilm formation, increase adhesion in the early stage of granule formation, and have a positive effect on AGS.

Below, as a result of an experimental example of the present invention, the change in size of sludge flocs according to the addition of AHL will be described. Figure 13 shows particle size distribution and corresponding sludge image according to an experimental example of the present invention.

As shown in Figure 13, addition of AHL signaling molecules increased the size of granules. The largest granules were formed in reactors with C6-HSL and C8-HSL. We showed that adding exogenous AHL signaling molecules in the early stages of granulation can promote microbial activity and biomass growth rate and improve sludge granulation. Additionally, among AHLs, C8-HSL and C10-HSL have a strong positive correlation with average granule size, and there is a strong correlation between AHL levels and granule formation.

Below, MLSS and fixability will be explained as a result of an experimental example of the present invention. Figure 14 shows a change graph of MLSS, VS/TS, and SVI according to AHL type in an experimental example of the present invention.

As shown in Figure 14, the effect of AHL type on MLSS and MLVSS was significant. After 3 weeks, the MLSS of the control group without AHL was 2,125 mg/L, whereas when C8-HSL was added, the AHL signaling molecule increased to 2,930 mg/L. Additionally, when AHL was added, the VS/TS ratio increased by more than 85% compared to the control group, regardless of type.

Figure 14 shows SVI results showing sludge settling characteristics. In general, sedimentation properties decrease with increasing VS/TS ratio. However, in the experimental example of the present invention, the sedimentation characteristics of the sludge were improved despite the increase in the VS/TS ratio due to the addition of the AHL signal molecule. This is believed to be due to an increase in EPS content, especially PN, which contributes to the formation and stability of microbial aggregates despite an increase in the VS/TS ratio. These results show that AHL signaling molecules increase biomass concentration and improve sedimentation .

Below, additional experimental examples and results will be described in the case where C8-HSL, which has the greatest effect in promoting AGS formation and granulation, was added in the above-mentioned examples of the present invention.

Figure 15 shows a schematic diagram of a continuous reactor according to an experimental example of the present invention. The reactor volume is 2L and the sedimentation tank volume is 0.76L. The hydraulic retention time (HRT) was 10 days, and the solids were returned from the bottom of the sedimentation tank to maintain the retention time (SRT) of 30 to 40 days, DO was maintained below 2 mg/LO ₂ , and the air flow rate was 0.2 L. /min, room temperature was maintained (25°C), and the initial MLSS was 2,243 mg/L.

In an experimental example of the present invention, to determine the effect of N-acyl Homoserine Lactone on the aerobic granule process, C8-HSL (N-Octanoyl- L -Homoserine Lactone) was added to the continuous reactor shown in Figure 9 to form granules. and stability were confirmed.

Two continuous reactors (Reator A, Reactor B) were operated, Reactor A was used as a control (W/O AHL), and C8-HSL was added to Reactor B at a concentration of 5 μM (W/ AHL). C8-HSL was added to Reactor B starting at the 40th day point.) Synthetic wastewater simulating return water was used as influent, and the influent feed was maintained at 6°C using a chiller. you

Figure 16a shows a graph comparing the COD removal efficiency between the case where C8-CHL was injected according to an experimental example of the present invention (hereinafter referred to as W/AHL) and the case where C8-CHL was not injected as a control (hereinafter referred to as W/O AHL). Despite the doubling of the influent COD concentration in Phase III of Figure 16a, both Reactors A and B showed a COD treatment efficiency of more than 90% during the operation period, and the addition of the signal molecule C8-CHL did not significantly affect the COD removal rate. It appears that

Figure 16b shows a graph comparing the total nitrogen (T-N) removal efficiency of W/AHL and W/O AHL. Figure 16c shows a graph comparing the total phosphorus (T-P) removal efficiency of W/AHL and W/O AHL.

As shown in Figure 16b, high TN removal efficiency was observed after the DO concentration was maintained below 2 mg/LO ₂ by adjusting the aeration amount in Phase III, and in Reactor A (W/O AHL), the average was 69.69%. , it can be seen that Reactor B (W/ AHL), an experimental example of the present invention, shows a higher removal efficiency with an average of 76.75%.

This shows that C8-HSL is closely correlated with biological nitrogen removal and that the nitrogen removal rate increased with the addition of the signal molecule.

As shown in Figure 16c, in the case of T-P removal efficiency, Reactor A (W/O AHL) showed an average of 86.6%, and Reactor B (W/ AHL), an experimental example of the present invention, showed a higher removal efficiency of 90.1% on average. can be seen. It can be seen that the addition of C8-HSL does not have a significant effect on the removal of COD, but the removal efficiency of total nitrogen and total phosphorus increases with the addition of the signal molecule.

Figure 17 shows a graph of LB-EPS content change for W/O AHL (a) and W/AHL (b). And Figure 18 shows a graph of the change in TB-EPS content for W/O AHL (a) and W/AHL (b).

As mentioned earlier, EPS is generally composed of two layers: loosely-bound EPS (LB-EPS) and tightly-bound EPS (TB-EPS). It is known that TB-EPS forms the inner layer surrounding microbial cells, and LB-EPS covers TB-EPS to form the outer layer. To confirm changes in EPS during the formation and maturation of AGS due to the addition of C8-HSL, EPS was quantified based on the contents of PN and PS.

LB-PN and LB-PS tended to increase in Reactor B (W/ AHL), an experimental example of the present invention, increasing by 2.74 times and 3.56 times, respectively. TB-PN and TB-PS also showed higher contents in Reactor B. TB-PN was secreted in greater amounts in Reactor B, an experimental example of the present invention, compared to A, the control group, and TB-PS increased approximately 1.7 times from the initial 67.52 mg/g VSS in Reactor B, and was maintained until the end of operation. showed a trend.

Among EPS, C8-HSL appears to regulate the secretion of polysaccharides (PS) in particular and participate in QS, and both LB and TB-EPS can be seen to increase overall along with the improvement of granule formation and stability in Reactor B.

Figure 19 shows an average particle size comparison graph for W/O AHL (a) W/AHL (b), and Figure 20 shows images for W/O AHL (a) W/AHL (b). will be.

The initial particle size of both Reactors A and B showed an average particle size of about 200 μm, but decreased to less than 100 μm after 30 days of operation.

Signal molecules were added to Reactor B at the 40th day of operation, and granules exceeding an average particle size of 290 μm were formed in Reactor B within 110 days of operation. At this time, the particle size distribution of Reactor A, the control group, was around 160 μm. . At the end of operation, it can be seen that Reactor A had a particle size of around 200 μm, and Reactor B had an average particle size exceeding 300 μm. As a result of particle size analysis, it was confirmed that the size of the granules increased by 2.5 times and was maintained in Reactor B with C8-HSL added.

This confirmed that the addition of C8-HSL signal molecules can induce and promote the formation of granules and also play a role in maintaining the stability of granules.

In addition, the apparatus and method described above are not limited to the configuration and method of the above-described embodiments, but all or part of each embodiment can be selectively combined so that various modifications can be made. It may be composed.

1: Culture tank to promote aerobic granular sludge granulation
20: Granulation tank transfer pipe
30: Transfer pump
40: flow meter
100:Give up
110: Body
111: Bulkhead
120:Diffuser
121:Blower
122: Blow flow meter
130: Inlet
131: Sedimentation basin
140: 2nd DO measuring instrument
200: Granulation tank
210:Inner tube
220: Rhombic shaped part
221: Enlarged cervix
222: Reduction part
230: Rectifying plate
240:Agitator
241: Rotation axis
242: Impeller
243: Drive motor
250: Reaction tank
251:Outer cylinder
252: Bottom hopper
260: Outflow part
261: Inclined plate
262: Wear leak department
263:Spillway
270: 1st DO measuring instrument
271:MLSS measuring instrument
273: Sludge interfacial system
290:AGS harvest conveyor
291:Control equipment

Claims (10)

A culture tank for promoting aerobic granular sludge (AGS) granulation having a granulation tank and an aeration tank,
Granulation tank for AGS formation; and
It includes an aeration tank that mixes the effluent from the granulation tank and the influent sewage water to maintain the DO concentration above a set value,
The aeration tank has a main body with a closed top, a blower and a diffuser for supplying air into the main body, and a second DO meter that measures DO concentration,
The granulation tank includes an inner cylinder into which the effluent from the aeration tank flows, a stirrer installed so that the impeller is located at the bottom of the inner cylinder, an outer cylinder spaced apart from the inner cylinder, a reaction tank that is a space between the inner cylinder and the outer cylinder, and an inner cylinder provided outside the inner cylinder. A culture tank for promoting aerobic granular sludge granulation, characterized by having a reaction tank outlet.
According to clause 1,
In the aeration tank, the effluent of the granulation tank is introduced, and exogenous acyl homoserine lactone (AHL) is mixed with the wastewater influent,
It includes a separation member provided to separate the space where the granulation tank effluent, wastewater influent, and AHL are mixed,
A culture tank for promoting granulation of aerobic granular sludge, characterized in that the control unit controls the DO concentration in the aeration tank by controlling the blower based on the DO value measured by the second DO meter.
According to clause 2,
Aerobic granular sludge granulation, comprising a granulation tank transfer pipe that flows the effluent from the aeration tank into the inner cylinder, a transfer pump provided on one side of the granulation tank transfer pipe to provide power for transfer, and a flow meter. Culture tank for promotion.
According to clause 3,
It includes a diamond-shaped portion whose diameter is expanded at the position where the impeller is installed on the lower outlet side of the inner cylinder,
A culture tank for promoting aerobic granular sludge granulation, characterized in that a baffle plate is installed at the inner cylinder outlet at the lower end of the diamond-shaped portion to disperse the effluent and allow it to flow into the reaction tank.
According to clause 4,
The lower end of the external cylinder has a hopper shape whose diameter gradually decreases toward the lower side,
Aerobic granular sludge granules, characterized in that the cross-section between the inclined surface of the hopper and the reduced diameter portion of the diamond-shaped portion is larger than the cross-section of the inner cylinder outlet, thereby preventing AGS from flowing into the inner cylinder and AGS from settling in the lower hopper of the reaction tank. Culture tank to promote flowering.
According to clause 5,
It includes a first DO meter for measuring the DO value in the reaction tank, an MLSS meter for measuring the MLSS concentration in the reaction tank, and a sludge interface meter for measuring the sludge interfacial height in the reaction tank,
A culture tank for promoting aerobic granular sludge granulation, characterized in that the injection amount and injection timing of the wastewater influent and AHL are controlled based on the MLSS concentration value measured by the MLSS meter and the sedimentation property of the sludge.
According to clause 6,
The reaction tank outlet is equipped with an inclined plate to minimize the inflow of AGS and sludge,
It includes a weir outlet unit installed with a weir to minimize the outflow of filamentous bacteria and fine flocs from the effluent discharged from the reaction tank outlet,
A culture tank for promoting granulation of aerobic granular sludge, characterized in that the granulation tank effluent that has passed through the reaction tank outlet and the weir outlet flows into the inlet side of the aeration tank through an outlet passage.
According to clause 7,
The water flow in the reaction tank is,
The flow speed is the fastest at the point where it flows out through the inner tube outlet, and after the effluent moving upward along the side of the lower hopper of the reaction tank after passing the inner tube outlet reaches the maximum diameter part of the diamond-shaped part, the flow speed decreases and follows the outer tube. The flow speed is relatively fast, and in the area close to the inner tube, vortices are formed in contact with the downward flow in the reaction tank, and the flow speed is reduced.
A culture tank for promoting aerobic granular sludge granulation, characterized in that aerobic granulation is promoted, filamentous fungal growth is suppressed, and granulation enlargement is prevented by the hydrodynamic shear force caused by the vortex.
A control method of a culture tank for promoting aerobic granular sludge granulation according to any one of claims 1 to 8,
A first step of measuring the DO value of the aeration tank through a second DO meter and reaching the set first target value of the DO value of the aeration tank;
A second step in which the DO value of the granulating tank is measured through a first DO meter, and the DO value of the granulating tank reaches a set second target value;
A third stage in which oxygen consumption exceeds the target value;
A fourth step in which the MLSS concentration in the granulation tank is measured using an MLSS meter, and the MLSS concentration in the granulation tank reaches the target value;
A fifth step of stopping the stirring of the stirrer and measuring the sludge interfacial height through a sludge interfacial meter; and
A control method of a culture tank for promoting granulation of aerobic granular sludge, comprising: a sixth step of operating the control equipment of the AGS harvest transfer path when the sludge interface height reaches the target value.
According to clause 9,
In the first step, the blower is controlled to increase the blowing flow rate until the first target value is reached,
In the second step, the stirring speed and blowing flow rate are increased by controlling the stirrer and blower until the second target value is reached,
In the fourth step, the injection amount and injection timing of the influent water and AHL are determined based on the MLSS concentration value measured by the MLSS meter and the sedimentation property of the sludge, and the injection amount and injection time are determined with a stirrer until the MLSS concentration value reaches the target value. By controlling the blower, the stirring speed and blowing flow rate are increased.
In the fifth step, a culture tank control method for promoting aerobic granular sludge granulation, characterized in that the stirring speed and blowing flow rate are increased by controlling the stirrer and blower until the interface height reaches the target value.