KR100745201B1 - Apparatus for reducing sludge of anaerobic digester - Google Patents

Abstract

An apparatus for reducing the quantity of sludge of an anaerobic digester is provided to maximize the efficiency of reduction in the quantity of sludge. The apparatus for reducing the quantity of sludge of an anaerobic digester comprises an anaerobic digester(170), a circulation pipe(160), an ultrasonic reactor(150) and a steam mixer(190), wherein each sludge formed through a primary sedimentation basin(10) and a secondary sedimentation basin(20) circulates in the circulation pipe and the anaerobic digester and passes through a process of anaerobic digestion. The primary sludge formed by waste water flew in the primary sedimentation basin is concentrated by a mechanical concentrator(130) and flew in the circulation pipe via a primary supply line(132), the secondary sludge formed by waste water flew in the secondary sedimentation basin is concentrated in a centrifugal concentrator(40) and flew in the circulation pipe via a secondary supply line(142), and the primary sludge and the secondary sludge flew in the anaerobic digester are mixed in the anaerobic digester to form digested sludge, wherein the ultrasonic reactor puts ultrasonic cavitation on the digested sludge circulating along the circulation pipe.

Description

Apparatus for reducing sludge of anaerobic digester

1 is a block diagram showing a conventional anaerobic digester.

Figure 2 is a flow chart showing the process sequence of the sludge reduction apparatus of the anaerobic digester according to an embodiment of the present invention.

Figure 3 is a block diagram of a sludge reduction device of the anaerobic digester according to an embodiment of the present invention.

Figure 4 is an exemplary view showing the ultrasonic reactor of the sludge reduction apparatus of the anaerobic digester according to an embodiment of the present invention.

Figure 5 is a block diagram showing a steam mixer of the sludge reduction apparatus of the anaerobic digester according to an embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

10: primary clarifier 20: secondary clarifier

40: centrifugal concentrator 130: mechanical concentrator

150: ultrasonic reactor 160: circulating piping

161: discharge portion 162: inlet portion

170: anaerobic digester 180: temperature control device

190: steam mixer 191: non-return valve

In general, sewage treatment plants apply biological treatment techniques and recommend the combined treatment of high concentration organic waste such as livestock waste and food waste. In addition, in recent years, the development of an anaerobic digester having a high effect of sludge reduction is recommended, and technology development is being actively conducted to improve the efficiency of the anaerobic digester.

1 is a block diagram showing a conventional anaerobic digester.

As shown in FIG. 1, when the wastewater is introduced into the primary sedimentation basin 10, sludge in the wastewater is submerged by gravity and concentrated to form primary sludge. In addition, some of the wastewater introduced into the primary sedimentation basin 10 is introduced into the secondary sedimentation basin 20 through the bioreactor 15 and concentrated to form secondary sludge.

The primary sludge is introduced into the anaerobic digestion tank 70 through the transfer line 32 through the concentration tank 30, and the anaerobic digestion tank through the transfer line 42 through the centrifugal concentrator 40. 70) and mixed with the primary sludge.

The anaerobic digester 70 has one end connected to the lower side of the anaerobic digester 70, the other end is provided with a circulation line 60 connected to the upper side of the anaerobic digester 70, the inside of the anaerobic digester 70 The mixed sludge of is circulated through the circulation line 60.

In addition, a steam line 65 is connected to the upper portion of the anaerobic digester 70 so that the hot steam generated by the boiler 92 is moved, and the high temperature steam is connected to the anaerobic digester through the steam line 65. 70 is supplied inside.

However, the conventional sludge fire extinguishing device has the following problems.

First, the primary sludge was concentrated by gravity concentration that sinks by gravity in the primary sedimentation basin, resulting in low organic matter load ratio (OLR), and the secondary sludge was discharged from the biological process, so that the sludge was surrounded by mucous membranes, making it difficult to decompose. . Therefore, there is a limit to improve the digestion efficiency by digesting the mixed sludge formed by mixing the primary sludge and the secondary sludge only in the anaerobic digestion process in the anaerobic digester.

Second, there is a problem that can not maximize the amount of methane gas generated for the injected organic material due to the degradation of the digestion efficiency of the mixed sludge.

Third, when the steam line connected to the anaerobic digester for the activation of anaerobic digestion is connected to the upper part of the anaerobic digester and the steam is supplied to the upper part of the anaerobic digester, the mixing state in the anaerobic digester is poor. The heat is stagnated in the upper portion, which prevents efficient temperature transfer inside the anaerobic digester. Accordingly, the difference in temperature between the upper portion and the lower portion is increased, thereby lowering the anaerobic digestion efficiency.

In order to solve the problems as described above, an object of the present invention is to provide a sludge reducing device of the anaerobic digester with improved efficiency.

In order to achieve the above object, the present invention provides an anaerobic digestion tank in which a digestion process is performed by introducing a mixed sludge formed by inflowing and mixing secondary sludge concentrated from a primary sludge and a secondary sludge; A discharge part connected to the upper side of the anaerobic digester to discharge digested sludge in the anaerobic digester and the secondary sludge flows in; Circulation pipe in which the inlet portion is formed to be introduced; And it is provided with the inlet, the steam generated in the boiler is connected to the steam line is moved to provide a sludge reduction apparatus of the anaerobic digestion tank comprising a steam mixer for heating the circulating sludge passing through the inlet.

Here, one side of the circulation pipe is an oscillator for generating an ultrasonic wave to apply a physical force by cavitation (cavitation) to the circulation sludge circulating through the circulation pipe, and a vibration plate vibrating by the ultrasonic wave generated in the oscillator It is preferable that an ultrasonic reactor is included.

In addition, the steam mixer is preferably provided with a non-return valve so that the circulation circulating sludge does not flow back to the steam line.

In addition, the steam line is provided with an actuator valve for controlling the amount of steam, a temperature sensor provided on both sides of the steam mixer to measure the temperature of the circulating sludge circulating, and a control unit for controlling the actuator valve by receiving a signal from the temperature sensor It is preferable to further include a temperature control device comprising.

And, the primary sludge is concentrated in a mechanical thickener through an adjustment tank in the primary sedimentation basin, the secondary sludge is preferably concentrated by a mechanical centrifugal concentrator.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described.

Figure 2 is a flow chart showing the process sequence of the sludge reduction apparatus according to an embodiment of the present invention.

As shown in Figure 2, the sludge reduction device is preferably made of an anaerobic digestion tank 170, the circulation pipe 160, the ultrasonic reactor 150 and the steam mixer 190. Here, each sludge formed through the primary sedimentation basin 10 and the secondary sedimentation basin 20 is circulated inside the circulation pipe 160 and the anaerobic digestion tank 170 to undergo an anaerobic digestion process. In this case, physical and chemical forces may be applied to the sludge particles by the ultrasonic cavitation phenomenon (cavitation) generated by the ultrasonic reactor 150 provided in the circulation pipe 160, and thus the sludge may be destroyed. Solubilization may increase the digestion efficiency of the anaerobic digester 170.

In detail, the primary sludge formed by inflow of the wastewater into the primary sedimentation basin 10 is preferably concentrated through a mechanical concentrator 130, and some of the wastewater introduced into the primary sedimentation basin 10 is formed by living organisms. The reactor 15 is concentrated to secondary sludge through the secondary sedimentation basin 20 and centrifugal concentrator 40.

In addition, the primary sludge and the secondary sludge are preferably introduced into the circulation pipe 160 and then moved to the inside of the anaerobic digester 170 in communication with the circulation pipe 160.

The first sludge and the second sludge introduced into the anaerobic digestion tank 170 is mixed with each other to be digested sludge, the digested sludge is circulated sludge through the circulation pipe 160 communicated to the anaerobic digester 170 It is desirable to go through a cycle repeatedly.

On the other hand, one side of the circulation pipe 160 is preferably provided with an ultrasonic reactor 150 that can generate ultrasonic vibration, the ultrasonic reactor 150 is the circulating sludge by cavitation (cavitation) by the ultrasonic wave It can destroy and solubilize, thereby improving anaerobic digestion efficiency.

And, the other side of the circulation pipe 160 is preferably provided with a steam mixer 190 for supplying the hot steam generated in the boiler 92 to the inside of the circulation pipe 160, through this, As the warmed circulating sludge flows into the anaerobic digester 170, the anaerobic digestion efficiency of the sludge may be further improved.

Figure 3 is a block diagram of a sludge reducing device of the anaerobic digester according to an embodiment of the present invention.

As shown in FIG. 3, when primary sludge is formed from the wastewater introduced into the primary sedimentation basin 10, the primary sludge is transferred to the mechanical concentrator 130 through the first transfer line 111. desirable.

Here, the mechanical concentrator 130 may be composed of a Gravity Belt Thickener or a conventional mechanical concentrator that is introduced onto the belt and concentrated with a flocculant.

As such, the primary sludge may be lowered in the water content of the sludge while passing through the mechanical concentrator 130, thereby increasing the organic load of the primary sludge.

On the other hand, between the primary sedimentation basin 10 and the mechanical concentrator 130 may be further provided with an adjustment tank 18 provided with a circulation pump or an underwater pump, the mechanical concentrator is discharged from the primary sedimentation basin (10) The primary sludge before being transferred to 130 may be passed through the adjustment tank (18).

The primary sludge is circulated in the adjusting tank 18 by the circulation pump or the water pump, through which the concentration distribution of the solids in the primary sludge can be maintained uniformly. When tea sludge is introduced, the concentration efficiency in the mechanical thickener 130 may be further improved.

Then, some of the waste water introduced into the primary sedimentation basin 10 is moved to the bioreactor 15 through the second transfer line 12, and then flows into the secondary sedimentation basin 20, the secondary Secondary sludge precipitated in the waste water introduced into the sedimentation basin 20 is concentrated through a centrifugal concentrator 40.

On the other hand, the anaerobic digestion tank in which the anaerobic digestion process is performed is preferably a circulation pipe 160 is connected, where the circulation pipe 160 is connected to one side of the anaerobic digester 170, the anaerobic digester The discharge part 161 through which the sludge is discharged in 170 is connected to the lower side of the anaerobic digester 170, and the sludge moved through the discharge part 161 flows back into the anaerobic digester 170. It is preferable to include an inlet 162 to be.

The secondary sludge is introduced into the circulation pipe 160 through the second supply line 142 and circulated, and the primary sludge is concentrated in the mechanical concentrator 130 and then through the first supply line 132. It is introduced into the circulation pipe 160.

In addition, the primary sludge and the secondary sludge introduced into the anaerobic digester 170 are mixed in the anaerobic digester 170 to form digested sludge.

The digested sludge is discharged back to the discharge portion 161 communicated with the upper side of the anaerobic digester 170 and circulated along the circulation pipe 160, and introduced into the second supply line 142. It is mixed with the secondary sludge, and again mixed with the new primary sludge introduced into the discharge unit 162 through the first supply line 132 is repeatedly passed through the process introduced into the anaerobic digestion tank 170.

At this time, one side of the circulation pipe 160 is preferably provided with an ultrasonic reactor 150 for applying ultrasonic cavitation (cavitation) to the digestive sludge circulating along the circulation pipe 160.

The ultrasonic reactor 150 applies ultrasonic cavitation (cavitation) to the sludge to cause the molecules present in the liquid medium to vibrate at their average positions, and the compression cycle in which the distance between the molecules of the molecules in the medium is closer by the vibration. The phenomenon of the expansion cycle away from can occur repeatedly.

In this case, when the molecules in the medium reach an expansion cycle process in which the distance between each molecule is far, the distance between the critical molecules capable of maintaining the liquid state may be farther away, and a cavity may be formed in the liquid.

The surface area of the cavity thus formed may be greater than during the expansion cycle so that the rate of diffusion into the cavity from the solution around the cavity during the expansion cycle may be greater than the rate of diffusion into the liquid around the cavity during the compression cycle.

Therefore, a cavity in which the rate of expansion in the expansion cycle is larger than the rate of compression during the compression cycle may be destroyed according to a cavitation phenomenon which is instantaneously destroyed after a certain degree.

Due to the cavitation phenomenon, the circulating sludge that is moved through the circulation pipe 160 may be solubilized by the ultrasonic reactor 150 to cause destruction of the sludge mucosa or sludge cells.

Accordingly, the organic material is eluted from the cells of the destroyed organic material, the organic material can be used as a substrate of the microorganism in the anaerobic digestion process, and the organic material which is easy to decompose and of good quality is hydrolyzed and acid fermented during anaerobic digestion. In addition, organic matter is reduced through methane fermentation, and the reduced organic matter is methane gasified to maximize the production of methane gas.

In addition, as the cell walls of microorganisms in the sludge irradiated with ultrasonic waves are destroyed, moisture in cells such as internal water may be expelled, and the dehydration efficiency may be remarkably increased. Finally, the amount of dewatered sludge (dehydrated cake) to be disposed of is reduced. Can be.

In addition, the inlet 162 communicating with the lower side of the anaerobic digester 170 is preferably provided with a steam mixer 190 connected to the steam line 165 to move the steam generated in the boiler 92.

Through this, the circulating sludge moved into the inlet 162 is warmed while passing through the steam mixer 190 to be introduced into the anaerobic digester 170.

At this time, as the inlet portion 162 communicates with the lower side of the anaerobic digester 170, the temperature transmitted by the sludge circulated and introduced naturally diffuses to the upper portion, and the temperature difference between the upper and lower portions of the inside of the anaerobic digester 170 is increased. Can be minimized.

And, since the temperature inside the anaerobic digester 170 can be maintained uniformly, it is possible to maintain the optimum temperature in the anaerobic digester 170, through which anaerobic digestion can be made more efficient.

Figure 4 is an exemplary view showing the ultrasonic reactor of the sludge reduction apparatus of the anaerobic digester according to an embodiment of the present invention.

As shown in Figure 4, the ultrasonic reactor 150 is preferably provided in the flow direction of the circulation pipe 160 to minimize the disturbance of the movement of the sludge.

To this end, flanges 158 and 159 are provided at both ends of the flow path part 151 through which the sludge moves, and flanges formed at the ends of the discharge part 161 and the inlet part 162 to correspond to the flanges 158 and 159, respectively. 168, 169 and a fastening member such as a screw.

In addition, a plurality of oscillators 153 may be arranged in the longitudinal direction of the flow path part 151, and the diaphragm 155 may be coupled to an end of each oscillator 153.

At this time, the flow path portion 151 may be made of a cross-section of various shapes so that the oscillator 153 and the diaphragm 155 can be easily installed, and the sludge can be moved smoothly. Is preferred.

The generator 157 converts a power input into electrical energy of a high frequency, and converts the power input into mechanical energy through the oscillator 153 and the diaphragm 155 to transfer energy to the sludge moving through the flow path part 151. do.

In this case, the quantity of each of the oscillator 153 and the diaphragm 155 may be increased or a combination thereof may be performed in parallel according to the amount of sludge moving through the flow path part 151, and the shape of the flow path part 151 may be increased. Is not limited to any particular shape.

Figure 5 is a block diagram showing a steam mixer of the sludge reduction apparatus of the anaerobic digester according to an embodiment of the present invention.

As shown in Figure 5, the inlet 162 is preferably provided with the steam mixer 190.

Here, the steam mixer 190 is preferably installed in the flow path direction of the inlet 162, both ends of the steam mixer 190 may be flange-coupled with the inlet 162.

And, one side of the steam mixer 190 is preferably formed of the branch pipe portion 163, the branch pipe portion 163, such as flange coupling with the steam line 165 connected to the boiler (92 in FIG. 3) Can be connected in a way.

The steam mixer 190 is preferably formed in a shape that is expanded in the flow direction of the sludge moving through the inlet 162, through which the high-temperature steam moving through the steam line 165 is the steam It may be sucked into the mixer 190.

In addition, the branch pipe part 163 may be provided with a non-return valve 191 to prevent the sludge moving through the steam mixer 190 to be moved to the steam line 165.

Here, the non-return valve 191 is not limited to a specific shape, and may be a valve of a type in which a sludge backflow can be prevented, such as a check valve or a safety valve.

On the other hand, in order to adjust the amount of steam supplied by measuring the temperature of the sludge circulating through the anaerobic digestion tank 170 and the circulation pipe 160, it is preferable that the temperature control device 180 is further provided.

Here, the temperature control device 180 preferably comprises an actuator valve 182, a temperature sensor 184 and the controller 186.

First, the temperature sensor 184 is preferably installed in the inlet 162 coupled to both sides of the steam mixer 190 in order to measure the temperature of the sludge circulated to the inside of the inlet 162. Of course, the temperature sensor 184 may be installed on both sides of the steam mixer 190.

In addition, the actuator valve 182 is preferably provided in the steam line 165 to adjust the amount of steam moving through the steam line 165.

In addition, the controller 186 is provided to control the actuator valve 182 by receiving the temperature information measured by the temperature sensor 184 as an electrical signal and comparing it with a preset temperature value.

Through this, the temperature controller 180 measures the temperature of the sludge circulated through the temperature sensor 184 installed at the front and rear of the steam mixer 190, and transmits the temperature to the controller 186, the controller 186 is capable of automatically adjusting the amount of steam by adjusting the actuator valve 182 according to the set temperature, and thus, the internal temperature of the anaerobic digester 170 can be properly maintained.

As described above, the present invention is not limited to the above-described specific preferred embodiments, and various modifications by those skilled in the art to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Implementations are possible and such variations are within the scope of the present invention.

The effect of the sludge reduction apparatus according to the present invention described above is as follows.

First, the first sludge and the second sludge introduced into the anaerobic digester can be destroyed through the ultrasonic reactor and the hard cell wall can be destroyed by the cavitation phenomenon. Especially, the digestibility of the anaerobic digestion process can be improved by increasing the biodegradability of the secondary sludge. Can be. Accordingly, the amount of methane gas available as alternative energy can be maximized, and the amount of dewatered sludge waste can be reduced through anaerobic digestion.

Second, it is possible to increase the organic load factor (OLR) by increasing the solid concentration of the primary sludge through a mechanical concentrator, through which the treatment efficiency of the ultrasonic reactor can be further improved.

Third, the heated sludge may be introduced into the lower side of the anaerobic digester by providing a steam mixer in the circulation pipe flowing into the anaerobic digester, and thus the temperature difference inside the anaerobic digester can be minimized.

Fourth, as described above, not only the sludge to be disposed of can be reduced, but also the disposal cost can be reduced, and since the methane gas is used as a heat source for heating power production and sludge, the maintenance cost can be reduced and high concentration of methane gas. Since it can be used as a transportation air, it can be used as a basic technology in terms of utilization of renewable energy.

Claims (5)

An anaerobic digestion tank in which a digestion process of a mixed sludge formed by inflowing and mixing the primary sludge concentrated from the primary settler and the secondary sludge concentrated from the secondary settler is performed; An inlet portion connected to an upper portion of the anaerobic digester to discharge the mixed sludge and inflow of the secondary sludge, and an inlet portion to which the mixed sludge circulated connected to the lower portion of the anaerobic digester flows and inflow of the primary sludge A circulation pipe formed; And Sludge reduction apparatus of the anaerobic digestion tank is provided with a steam mixer which is provided in the inlet, and is connected to the steam line to move the steam generated in the boiler to pass the mixed sludge passing through the inlet. The method of claim 1, One side of the circulation pipe is characterized in that the ultrasonic reactor comprises an oscillator for generating an ultrasonic wave so that the cavitation (cavitation) is made to the mixed sludge circulating through the circulation pipe, and a diaphragm vibrating by the ultrasonic wave. Sludge reduction device of anaerobic digester. The method of claim 1, The steam mixer is a sludge reduction apparatus of the anaerobic digester, characterized in that the non-return valve is installed so that the circulating mixed sludge does not flow back to the steam line. The method of claim 1, The steam line includes an actuator valve for adjusting the amount of steam, a temperature sensor provided at both sides of the steam mixer to measure the temperature of the mixed sludge circulated, and a control unit for controlling the actuator valve by receiving a signal from the temperature sensor. Sludge reduction apparatus of the anaerobic digester characterized in that the temperature control device is further provided. The method of claim 1, The primary sludge is concentrated in a mechanical concentrator through an adjustment tank in the primary sedimentation basin, and the secondary sludge is introduced into the secondary sedimentation basin through a bioreactor and concentrated by a centrifugal concentrator. Sludge reduction device of the anaerobic digester characterized in that.

Images