KR101374305B1 - Anaerobic digestion system which combined with cross flow membrane and low intensity ultra sonication - Google Patents

Abstract

An anaerobic digestion system by an embodiment of the preset invention comprises the following: an anaerobic digestion tank including an organic sludge in which biogas generating microorganisms are dispersed; an ultrasonication device for emitting low intensity ultrasonic waves to the biogas generating microorganisms; a membrane separation device for returning the organic sludge contained in anaerobic digestion liquid of the organic sludge generated by the biogas generating microorganisms to the anaerobic digestion tank; and a control device controlling the ultrasonication device to intermittently emit the low intensity ultrasonic waves in predetermined emission intensity for a predetermined amount of time, and controlling the returning rate of the organic sludge in response to the filtration amount based on the membrane contamination of the membrane separation device. [Reference numerals] (110) Anaerobic digestion tank; (133) Ultrasonication device; (150) Membrane separation device

Description

ANAEROBIC DIGESTION SYSTEM WHICH COMBINED WITH CROSS FLOW MEMBRANE AND LOW INTENSITY ULTRA SONICATION

The present invention relates to an anaerobic digestion system combined with membrane bonding and low intensity ultrasound, and more particularly, to maintain a high concentration of microorganisms in an anaerobic digestion tank by applying a membrane separation device to block the outflow of the anaerobic digester. The present invention relates to an anaerobic digestive system that combines membrane bonding and low-intensity ultrasound that can maximize biogas generation by increasing the sludge digestion efficiency of organic matter by activating microorganisms by irradiating microorganisms with low-intensity ultrasound.

In general, biogas can be obtained by anaerobic digestion of organic substrates, also known as "methane fermentation".

As part of the low-carbon green growth in recent years, not only livestock manure, food waste, sewage sludge, but also agricultural by-products such as rice straw, barley straw, straw, rice hulls, cabbage, radish and onions, as well as bio-energy crops such as rapeseed and sunflower It is used to maximize the productivity of this biogas.

Anaerobic digestion of such fibrous organic substrates by anaerobic microorganisms requires a long residence time of about 50 days or more.

In addition, since the anaerobic digestion sludge sedimentation is poor during the treatment of the digestion liquid according to the organic substrate digestion of anaerobic microorganisms, there is a problem that the sludge outflow occurs.

Sludge outflow causes the loss of anaerobic microorganisms such as methane bacteria, resulting in lower extinguishing efficiency, lower gas production, and lower organic treatment efficiency.

The present invention has been made to solve this problem, it is possible to block the outflow of microorganisms in the anaerobic digestion tank and maintain the high concentration of microorganisms in the anaerobic digestion tank, digestion of microorganisms even without adding a sludge treatment facility generated in a pretreatment facility or a pretreatment facility It is to provide an anaerobic digestion system that combines membrane bonding and low-intensity ultrasonic waves to increase efficiency and maximize biogas generation rate and maximize organic waste reduction rate.

Anaerobic digestion system combined with membrane binding and low-intensity ultrasonic waves according to an embodiment of the present invention is a membrane separation device for blocking the outflow of biogas-generating microorganisms of the anaerobic digestion tank, and the biogas to activate the biogas-generating microorganisms Ultrasonic irradiation device for irradiating low-intensity ultrasonic waves to the gas generating microorganisms,
The ultrasonic irradiation apparatus includes an ultrasonic irradiation tank having a volume such that the constant sludge flow rate, which is the sum of the membrane conveyance sludge flow rate from the membrane separation device and the bypass organic sludge flow rate from the anaerobic digestion tank, stays for a predetermined time. do.

Anaerobic digestion system combined with membrane bonding and low-intensity ultrasonic waves according to an embodiment of the present invention is an anaerobic digestion tank having organic gas sludge in which biogas-generating microorganisms are distributed, for irradiating low-intensity ultrasonic waves to the biogas-generating microorganisms Ultrasonic irradiation apparatus, membrane separation device for conveying the organic sludge contained in the anaerobic digestion liquid of the organic sludge by the biogas generating microorganism to the anaerobic digestion tank, and the ultrasonic irradiation apparatus is a low intensity of a predetermined irradiation intensity for a predetermined time And controlling the ultrasonic wave to be irradiated intermittently and controlling the conveyance rate of the organic sludge in response to the amount of filtration according to the membrane fouling degree of the membrane separation device.
The ultrasonic irradiation apparatus includes an ultrasonic irradiation tank having a volume such that the constant sludge flow rate, which is the sum of the membrane conveyance sludge flow rate from the membrane separation device and the bypass organic sludge flow rate from the anaerobic digestion tank, stays for a predetermined time. do.

Anaerobic digestion system combined with membrane bonding and low-intensity ultrasonic waves according to an embodiment of the present invention is included in the anaerobic digestion tank having an organic sludge in which biogas generating microorganisms are distributed, the anaerobic digestion of the organic sludge by the biogas generating microorganisms Membrane separator for conveying the organic sludge to the anaerobic digestion tank, Bypass apparatus for extracting the bypass organic sludge flow rate from the anaerobic digestion tank corresponding to the flow rate of the membrane conveying organic sludge conveyed from the membrane separation device, the membrane conveyance The predetermined time for the predetermined sludge flow rate of the low intensity ultrasonic irradiation tank, the low intensity ultrasonic irradiation tank for returning the constant sludge flow rate, which is the sum of the organic sludge flow rate and the bypass organic material sludge flow rate for a predetermined time, to the anaerobic digestion tank Low intensity supersonic A comprises an ultrasound irradiation device and a control device for controlling the membrane separation device, the bypass device, the ultrasonic wave irradiation apparatus for irradiating,
The ultrasonic irradiation tank is characterized by having a volume such that a constant sludge flow rate, which is the sum of the membrane conveyance sludge flow rate and the bypass sludge flow rate, stays for the predetermined time.

According to an embodiment of the present invention, it is possible to block the outflow of microorganisms in the anaerobic digestion tank and maintain the inside of the anaerobic digester as a high concentration of microorganisms, and to increase the digestion efficiency of the microorganisms without adding a sludge treatment facility generated in the pretreatment facility or pretreatment facility It can maximize the amount of gas generated and maximize the rate of organic waste reduction.

1 is a block diagram showing a schematic configuration of an anaerobic digestion system according to an embodiment of the present invention.
Figure 2 is a graph showing the amount of methane generated according to the presence or absence of solid-liquid separation membrane of the anaerobic digestion system according to an embodiment of the present invention.
Figure 3 is a graph showing the amount of methane generated according to the low intensity ultrasonic treatment of the anaerobic digestion system according to an embodiment of the present invention.
Figure 4 is a schematic diagram of an anaerobic digestion system according to another embodiment of the present invention.
5 is a flowchart illustrating a control method of an anaerobic digestion system according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

First, an anaerobic digestion system according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

1 is a block diagram showing a schematic configuration of an anaerobic digestion system according to an embodiment of the present invention, Figure 2 is a graph showing the amount of methane generated according to the presence or absence of solid-liquid separation membrane of the anaerobic digestion system according to an embodiment of the present invention, 3 is a graph showing the amount of methane generated by the low intensity ultrasonic treatment of the anaerobic digestion system according to an embodiment of the present invention.

As shown in FIG. 1, the anaerobic digestion system 100 according to an embodiment of the present invention has an anaerobic digestion tank 110 for anaerobic digestion of organic matters by biogas generating microorganisms and low intensity to the biogas generating microorganisms. Ultrasonic irradiation apparatus 130 for irradiating the ultrasonic wave, and digestion fluid generated during the digestion of organic matter by the biogas generating microorganisms in the anaerobic digestion tank 110 to prevent the outflow of the biogas generating microorganisms It may include a membrane separation device 150, a control device for controlling the ultrasonic irradiation device 130 and the membrane separation device (150).

In the present specification, "low intensity ultrasound" is conventionally used for the purpose of reducing the microbial cell wall thickness to increase the substrate absorbency or destroying the substrate in order to increase the biogas generation efficiency of the anaerobic digester, or to improve the biodegradability. Ultrasonic energy with irradiation energy that is about 0.1 ~ 0.8KWh / m ³ (0.5) compared to 3.5 ~ 100KWh / m ³ (50) continuously irradiated with organic sludge to increase microbial activity Means.

Here, 50 and 0.5 represent the representative value of the conventional ultrasonic wave irradiated to the substrate and the representative value of the low intensity ultrasonic wave according to an embodiment of the present invention irradiated to the bio sludge, an embodiment of the present invention through comparison thereof The low intensity ultrasonic energy according to the present invention can be seen that uses about one hundredth of the ultrasonic energy compared to the ultrasonic energy used for irradiation to the substrate.

The anaerobic digestion tank 110 contains biogas producing microorganisms such as methane gas producing bacteria in organic sludge.

The anaerobic digestion tank 110 has an inlet pipe 111 through which organic matter is introduced, and a digestive fluid outlet tube 113 through which the biogas microorganisms flow out digestive fluid anaerobicly digested the organic matter introduced through the inlet pipe 111. It may be further provided.

In addition, the anaerobic digestion tank 110 may be preferably provided with a biogas outlet pipe 115 through which the biogas containing methane is collected and discharged above the anaerobic digestion tank 110.

In the anaerobic digestion tank system 100 according to an embodiment of the present invention, the ultrasonic irradiation apparatus 130 includes an ultrasonic vibrator 131 disposed inside or inside the anaerobic digestion tank 110 and the ultrasonic vibrator 131. Ultrasonic generator 133 for generating low-intensity ultrasound that can increase the microbial activity to vibrate at a predetermined frequency.

The controller 180 controls the ultrasonic generator 133 to generate low intensity ultrasonic waves at about 0.1 to 0.8 KWh / m ³ (0.5), which can increase microbial activity.

The ultrasonic vibrator 131 may be installed in a plurality of spaced apart from the inner wall of the anaerobic digestion tank 100 so as to evenly irradiate the biogas generating microorganisms, it may be distributed in the anaerobic digestion tank 100. .

In the anaerobic digestion system 100 according to an embodiment of the present invention, a membrane separation device 150 was used to prevent sludge loss due to anaerobic digestion.

The membrane separation device 150 is a pressure pump 151 for pumping the anaerobic digestion liquid from the anaerobic digestion tank 110 through the outlet pipe 113 at a predetermined pressure and pumped by the pressure pump 151 Pressurized membrane 153 for separating anaerobic digestion into anaerobic digestion sludge and filtrate, filtrate discharge line 155 for treating the filtrate and anaerobic digestion sludge to be separated through the pressurized membrane 153; A discharge line 154 for conveying to the anaerobic digestion tank 110 is included.

The controller 180 is a pressure applied by the pressure pump 151 when the pressure type membrane 153 is heavily contaminated according to the degree of contamination of the pressure type membrane 153 of the membrane separation device 150. By increasing the control solution so that the filtrate corresponding to the organic matter inflow amount introduced through the inlet pipe 111 to the anaerobic digestion tank 110 can be discharged through the discharge line (155).

Membrane separation device 150 of the anaerobic digestion system 100 according to an embodiment of the present invention, the membrane fouling occurs easily when the viscosity of the anaerobic digestion sludge in the case of the immersion membrane, the digestion gas sparging of the immersion membrane ( Since the biogas production can be reduced because it is used for a sparging), a pressurized membrane 153 is used.

Membrane separation device 150 of the anaerobic digestion system 100 according to an embodiment of the present invention can control the membrane fouling of the pressure-type membrane 153 by controlling the pressure of the pressure pump 151, Anaerobic digestion sludge is discharged through the discharge line 154 to the anaerobic digestion tank 110 to block the outflow of the anaerobic digestion sludge to prevent the loss of biogas generating microorganisms.

Referring to FIG. 2, even when a continuous operation is performed for four months in the case of using the membrane separator 150 to which a predetermined pressure is applied, the increased methane gas production rate is maintained as compared with the case in which the membrane separator 150 is not used. I can see that

As such, since the sludge and the microorganisms contained therein can be returned to the anaerobic digestion tank 110 by using the membrane separation device 150, the problem of methane bacteria loss due to sludge leakage from the anaerobic digestion tank 110 can be solved. .

In addition, since the concentration of microorganisms in the anaerobic digestion tank 110 can be maintained at a high concentration, methane gas production can be increased and organic matter treatment efficiency can be increased.

Referring to FIG. 3, when the low intensity ultrasonic pretreatment was not performed on the organic material of the anaerobic digestion tank 110, the methane gas generation amount was 0.3 L / g after 6 days, whereas the low intensity ultrasonic pretreatment was performed after 6 days of methane gas. It can be seen that the generation amount is more than three times more than 0.8L / g.

To this end, Experimental Example 1 was carried out.

(Experimental Example 1)

Courage A Container B Dose 0.3W / sludge ml - Investigation Hours / At Rest 20 minutes / 6 days - During anaerobic digestion 100 days total 100 days total

As shown in Table 1, the container A and the container B (serrum bottle) which are 100 ml or more are prepared, and 50 ml each of substrates, such as food, is put into the container A and the container B, respectively, and the container A has low intensity ultrasonic 0.3 W / slurry. 50 ml of sludge irradiated with 20 ml of ml (= 300 W / L) for 20 minutes, and 50 ml of normal sludge was added to vessel B without sonication and stored in a 35 ° C constant temperature water bath. Measured and analyzed.

In this case, when the ultrasonic dose 0.3W / sludge ml is irradiated for 20 minutes and has a 6-day rest period, when the unit conversion is performed as shown in Equation 1, a low intensity irradiation energy of about 0.7Kwh / m ³ is irradiated. Can be.

(0.3W / ml) x (1000ml / 1L) x (1000L / 1m 3) x (1Kw / 1000W) x (20min / 60min) x (1 / (24x6 days) = about 0.7Kwh / m ³ .... ........................... (Equation 1)

It can be seen that the amount of biogas generated when the low-intensity ultrasonic irradiation energy of about 0.7 Kwh / m ³ is generated three times or more as compared with the case where the ultrasonic treatment is not performed.

As described above, when the range of low-intensity ultrasound irradiation energy is 0.1 ~ 0.8KWh / m ³ (0.5), if less than 0.1KWh / m ³ It does not help the microbial activity, if more than 0.8KWh / m ³ In order to stress the sludge or microorganisms it is desirable to investigate the amount of energy in the appropriate range.

On the other hand, in the anaerobic digestion system 100 according to an embodiment of the present invention, it is necessary to irradiate low intensity ultrasound of a certain irradiation density to the biogas generating microorganisms of the anaerobic digestion tank 110.

To this end, when the biogas generating microorganisms are distributed in the sludge at a constant density, the amount of the sludge to the anaerobic digestion tank 110 needs to be constant.

However, according to the membrane separation device 150, the amount of the filtrate discharged through the discharge line 155 of the pressure-type membrane 153 also changes as the membrane contamination of the pressure-type membrane 153 increases. In order to control the amount of filtrate, the sludge conveyance rate according to the discharge line 154 should also be controlled differently.

That is, according to the degree of membrane fouling of the pressurized membrane 153, 4Q is conveyed through the discharge line 154 by forcibly pumping the organic digestion treatment solution of 5Q through the outlet pipe 113 of the anaerobic digestion tank 110. The pump may be forced to pump 10Q, and 9Q may be conveyed through the discharge line 154.

As such, the return rate of the organic digestion solution returned to the anaerobic digestion tank 110 is changed along the discharge line 154, and if the transport rate of the organic digestion solution is changed, low-intensity ultrasonic waves having a predetermined appropriate irradiation density are irradiated. It becomes difficult to do.

4 and 5, an anaerobic digestion system 200 according to another embodiment of the present invention will now be described.

Figure 4 is a schematic configuration diagram of an anaerobic digestion system according to another embodiment of the present invention, Figure 5 is a flow chart illustrating a control method of the anaerobic digestion system according to another embodiment of the present invention.

As shown in FIG. 4, the anaerobic digestion system 200 according to another embodiment of the present invention is similar to the anaerobic digestion system 100 according to an embodiment of the present invention for biogas generating microorganisms to anaerobic organic matter. An anaerobic digestion tank 210, an ultrasonic irradiation apparatus 230 for irradiating the biogas generating microorganisms with low intensity ultrasonic waves, and the biogas generating microorganisms in the anaerobic digestion tank 210 generated during the digestion of organic matter And a membrane separation device 250 for preventing the outflow of the biogas-generating microorganism by membrane separation of the digestive liquid, and a control device 280 for controlling the ultrasonic irradiation device 230 and the membrane separation device 250. .

The anaerobic digestion system 200 according to another embodiment of the present invention and the anaerobic digestion system 100 according to an embodiment of the present invention are different from the ultrasonic irradiation device 230 for the biogas generating microorganisms. In addition to the anaerobic digestion tank 210 so as to irradiate low-intensity ultrasonic wave of the desired irradiation density of the low-intensity ultrasonic treatment tank 220 is further provided, the rate of return to the low-intensity ultrasonic treatment tank 220 by A small amount of sludge, i.e., a certain amount of biogas generating microorganisms, is irradiated with a low intensity ultrasonic wave of a predetermined desired irradiation density, and the activated biogas microorganisms are supplied to the anaerobic digestion tank 210 to provide anaerobic digestion in the anaerobic digestion tank 210. To activate it.

To this end, the low-intensity ultrasonic treatment tank 220 is not only connected to the conveying line 255 of the membrane separation device 250, but also bypasses other than the digested organic matter outlet pipe 213 from the anaerobic digestion tank 110. The anaerobic digestion organics are supplied through the apparatus 270 to keep the anaerobic digestion organics, ie, sludge conveyance, to the low intensity ultrasonic treatment tank 220 constant.

The bypass device 270 includes a bypass pump 271 and a bypass line 273, and the bypass pump 271 of the bypass device 270 is controlled by the controller 280. The sludge conveyance rate to the intensity ultrasonic treatment tank 220 is controlled to be constant.

In detail, when the sludge of 5Q is discharged through the digestion organic matter outlet pipe 213 of the anaerobic digestion tank 210, and the membrane separation apparatus 250 conveys the sludge of 4Q, the anaerobic digestion tank 210 The low intensity ultrasonic waves through the conveying line 255 even when the sludge of 10Q flows out through the extinguishing organic matter outlet pipe 213 and the conveying rate is changed, such as when the membrane separation unit 250 conveys the sludge of 9Q. The sludge of 4Q and 9Q is introduced into the treatment tank 220, and the sludge of 6Q and 1Q is introduced into the low intensity ultrasonic treatment tank 220 from the anaerobic digestion tank 210 through the bypass line 273. By the low-intensity ultrasonic treatment tank 220 can be controlled so that the rate of return to the anaerobic digestion tank 210 through the second conveying line 275 is always constant.

Therefore, since the constant sludge flow rate flows in the low intensity ultrasonic irradiation tank 220, the control device 280 controls the irradiation intensity of the ultrasonic generator 233 with respect to the constant sludge flow rate so that low intensity ultrasonic waves having a constant irradiation density are irradiated. can do.

For example, when the volume of the anaerobic digestion tank 210 is 30m ³ , the daily amount of organic matter is 1m ³ , and the residence time is 30 days, the low-intensity ultrasonic irradiation density is irradiated at 330W / L for 20 minutes, and rests for 6 days. When time is given, the method of irradiating low-intensity ultrasonic waves with a constant irradiation density will be described.

The circulation rate of the anaerobic digesters 210, assuming that during the six days rest period is filled the volume 30m ³ for the anaerobic digestion tank, since the sludge of 30m ³ cycle, 30m ^3/6, that is 5m ³ / day The controller 280 controls the membrane separator 250 and the bypass device 270 to fit.

That is, the control device 280 from the membrane conveying sludge flow rate and the anaerobic digestion tank 210 is conveyed to the low intensity ultrasonic irradiation tank 220 through the first conveying line 255 of the membrane separation device 250 Feedback control is performed such that the sum of the pumping sludge flow rates supplied to the low intensity ultrasonic irradiation tank 220 through the bypass pump 271 becomes a circulation flow of 5 m ³ / day of the anaerobic digestion tank 210.

The volume of the low-intensity ultrasonic irradiation tank 220 is 5m ³ / day x 20 minutes (1 day / 1440 minutes) (1000L / m ³ ) when the constant circulation flow rate 5m ³ / day stays for 20 minutes That is, 7L.

 The control device 280 is irradiated by controlling the ultrasonic generator 210 of the ultrasonic irradiation device 230 so that a low intensity ultrasonic wave of a constant irradiation density 330W / L to the 7L low intensity ultrasonic irradiation tank 220 is irradiated The intensity can be irradiated to 330W / Lx7L, or 2.3KW.

The control device 280 is connected to the ultrasonic generator 233 connected to the ultrasonic vibrator 231, the irradiation intensity of the ultrasonic wave, the operating time of the ultrasonic vibrator 231 and the neighboring ultrasonic vibrator 231 The low-intensity ultrasound may be controlled by controlling the circulation flow rate of the anaerobic digestion tank 210 by feedback control of the bypass device 270 and the membrane separation device 250 as well as the interval between the operation time. The irradiation density of is uniformly adjusted to suit the activity of the biogas generating microorganism.

That is, when the anaerobic digestion tank 210 is filled with organic sludge and biogas-generating microorganisms (S110), the membrane separation apparatus 250 may be supplied to the anaerobic digestion tank 210 to continuously supply a certain amount of organic sludge. The pressure of the pressure pump 251 is controlled to correspond to the amount of the filtrate discharged through the pressurized membrane 253 to convey a predetermined membrane conveying flow rate through the first conveying line 255 (S120). ).

The membrane conveying sludge flow rate conveyed from the membrane separation device 230 is determined to be less than the predetermined sludge flow rate set to flow into the low-intensity ultrasonic irradiation tank 220 (S130), and is conveyed from the membrane separation device 230 If it is determined that the membrane conveyed sludge flow rate is less than the predetermined sludge flow rate set to flow into the low-intensity ultrasonic irradiation tank 220 (S131), as much as the difference between the constant sludge flow rate and the membrane conveyed sludge flow rate from the anaerobic digester 110. Bypass the sludge flow rate of the pump using the bypass pump 271 is supplied to the low-intensity ultrasonic irradiation tank 220 through the bypass line (273) (S240).

The control device 280 determines whether the constant sludge flow rate set in the low intensity ultrasonic irradiation tank 220 is input (S250), and when it is determined that the constant sludge flow rate set in the low intensity ultrasonic irradiation tank 220 is introduced. In operation S251, the low-intensity ultrasound irradiation apparatus 230 irradiates the low-intensity ultrasonic wave having a predetermined irradiation intensity to the low-intensity ultrasonic irradiation tank 220 for a predetermined irradiation time (S260). While the low-intensity ultrasonic wave of a constant irradiation intensity is irradiated with a constant sludge flow rate to the anaerobic digester 210.

As described above, the anaerobic digestion tank improvement apparatus 200 according to another embodiment of the present invention may prevent the sludge from flowing out by allowing a certain sludge flow rate to be circulated to the anaerobic digestion tank 210 using the membrane separator 250. In addition, feedback control is performed such that the membrane conveying sludge flow rate returned from the membrane separation device 250 and the bypass sludge flow rate bypassed from the anaerobic digestion tank 210 using the bypass device 270 are constant sludge flow rate. Since the low-intensity ultrasonic wave of a predetermined intensity can be irradiated for a predetermined irradiation time so that a predetermined sludge flow rate flows into the ultrasonic low-intensity irradiation tank 220, a low-intensity ultrasonic wave having an appropriate irradiation density can increase the activity of microorganisms. Irradiation can increase biogas production.

110, 210: anaerobic digestion tank 220: low intensity ultrasonic irradiation tank
130, 230: ultrasonic irradiation device 150, 250: membrane separation device
280: controller

Claims (10)

A membrane separation device for blocking the outflow of biogas producing microorganisms in the anaerobic digestion tank,
An ultrasonic irradiation apparatus for irradiating low-intensity ultrasonic waves to the biogas generating microorganisms to activate the biogas generating microorganisms,
And the ultrasonic irradiation apparatus includes an ultrasonic irradiation tank having a volume such that a constant sludge flow rate, which is the sum of the membrane conveyance sludge flow rate from the membrane separation device and the bypass slurry flow rate from the anaerobic digestion tank, is retained for a predetermined time. Anaerobic digestion tank having organic sludge in which biogas producing microorganisms are distributed;
An ultrasonic irradiation device for irradiating low intensity ultrasonic waves to the biogas generating microorganisms;
A membrane separation device for returning the organic sludge contained in the anaerobic digestion liquid of the organic sludge by the biogas generating microorganism to the anaerobic digestion tank; And
A control device for controlling the ultrasonic irradiation device to intermittently irradiate low-intensity ultrasonic waves of a predetermined irradiation density for a predetermined time, and to control the conveyance rate of the organic sludge differently in response to the amount of filtration according to the membrane fouling degree of the membrane separation device Including;
The ultrasonic irradiation apparatus includes an ultrasonic irradiation tank having a volume such that a constant sludge flow rate, which is the sum of the membrane conveyance sludge flow rate from the membrane separator and the bypass organic sludge flow rate from the anaerobic digestion tank, stays for a predetermined time. . Anaerobic digestion tank having organic sludge in which biogas producing microorganisms are distributed;
A membrane separation device for returning the organic sludge contained in the anaerobic digestion liquid of the organic sludge by the biogas generating microorganism to the anaerobic digestion tank;
A bypass device for extracting the bypass organic sludge flow rate from the anaerobic digestion tank in response to the membrane conveyed organic sludge flow rate returned from the membrane separation device;
A low intensity ultrasonic irradiation tank for conveying the constant sludge flow rate, which is the sum of the membrane conveyance organic sludge flow rate and the bypass organic matter sludge flow rate, to the anaerobic digestion tank for a predetermined time;
An ultrasonic irradiation device for irradiating low intensity ultrasonic waves for a predetermined time with respect to a constant sludge flow rate of the low intensity ultrasonic irradiation tank; And
It includes a control device for controlling the membrane separation device, the bypass device, the ultrasonic irradiation device,
The ultrasonic irradiation tank has an anaerobic digestion system having a volume such that a constant sludge flow rate, which is the sum of the membrane conveyed sludge flow rate and the bypass sludge flow rate, stays for the predetermined time. 4. The method according to any one of claims 1 to 3,
The low intensity ultrasound has an irradiation energy that increases the activity of the biogas generating microorganisms below the irradiation energy irradiated to reduce the thickness of the biogas generating microbial cell wall or destroy the organic material. 4. The method according to any one of claims 1 to 3,
The ultrasonic irradiation apparatus is an anaerobic digestion system comprising an ultrasonic generator for irradiating the low intensity ultrasonic waves during the predetermined irradiation time, and an ultrasonic vibrator vibrating for the predetermined irradiation time according to the frequency generated by the ultrasonic generator. 4. The method according to any one of claims 1 to 3,
The membrane separation device includes a pressurized filtration membrane for filtering the anaerobic digestion liquid of the organic sludge by the biogas generating microorganism, a pressurized pump whose pressure is controlled according to the membrane fouling degree of the pressurized filtration membrane, and filtration in the anaerobic digestion liquid. An anaerobic digestion system comprising a discharge line for discharging the liquid, and a return line for conveying the organic sludge in the anaerobic digestion liquid to the anaerobic digestion tank. 4. The method according to any one of claims 1 to 3,
Anaerobic digestion system is controlled to have a rest period for 5 to 7 days after the irradiation density of the low-intensity ultrasound is 250 to 400W / L, 15 minutes to 30 minutes. The method of claim 3, wherein
The bypass device includes a bypass pump for pressurizing and pumping a bypass sludge flow rate varying in response to the membrane conveying organic sludge flow rate of the membrane separation device from the anaerobic digestion tank, and a bypass sludge pressurized and pumped by the bypass pump. An anaerobic digestion system comprising a bypass line for transferring a flow rate from said anaerobic digestion tank to said ultrasonic irradiation tank. delete The method of claim 3, wherein
The control device is a rate of return of organic sludge to the anaerobic digestion tank and the bypass organic material by the bypass device in response to the amount of filtration according to the membrane contamination of the membrane separation device so that the inflow rate of organic sludge in the ultrasonic irradiation tank is constant. Feedback control of sludge flow rate,
Anaerobic digestion system for controlling the ultrasonic irradiation tank to irradiate low intensity ultrasound of a predetermined intensity for a predetermined time.

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