JP2012081382A - Biological liquid waste treatment apparatus and biological liquid waste treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological liquid waste treatment apparatus and a biological liquid waste treatment method, capable of sufficiently decomposing oil or fat separated from oil-containing liquid waste.SOLUTION: The oil-containing liquid waste is separated into liquid waste containing the oil or fat at a lower concentration and liquid waste containing the oil or fat at a higher concentration by means of an oil concentration/separation apparatus 1; the liquid waste containing the oil or fat at a lower concentration is introduced into a methane fermentation apparatus 2, and subjected to a methane fermentation treatment using microbial sludge, while the liquid waste containing the oil or fat at a higher concentration is introduced into an oil decomposition apparatus 3 and stirred by means of a stirring apparatus 11. The state of the oil in the liquid waste containing the oil or fat at a higher concentration is acquired by means of an oil state acquisition means 10, and the stirring condition of the stirring apparatus 11 is changed in accordance with the state of the oil. According to this, the oil contained in the high-concentration oil liquid waste is surely decomposed using the microbial sludge while suppressing the formation of masses of the oil.

Description

  The present invention relates to a biological wastewater treatment apparatus and a biological wastewater treatment method for decomposing organic substances in oil-containing wastewater.

  As a biological wastewater treatment apparatus that decomposes organic matter in wastewater, a device that performs methane fermentation treatment of wastewater is known. In such a biological wastewater treatment apparatus, the methane fermentation treatment may be hindered when the fat and oil concentration of the wastewater is high. That is, when the concentration of fats and oils in the wastewater increases, methane bacteria may float with the fats and oils and flow out of the methane fermentation treatment tank. In addition, methane bacteria are covered with oils and fats, and the ability of methane bacteria to decompose organic matter may be impaired. As a biological wastewater treatment device that solves such problems, an oil-containing wastewater is introduced, and a fat concentration separator that separates into a low-concentration fat wastewater and a high-concentration fat wastewater, and a separated low-concentration fat wastewater are introduced. , A methane fermentation device that performs methane fermentation of low-concentration fat wastewater using microbial sludge, and an oil decomposition device that introduces the separated high-concentration fat wastewater and decomposes fats and oils in high-concentration fat wastewater using microbial sludge And a stirrer that stirs high-concentration fat and oil wastewater introduced into the fat and oil decomposer (see, for example, Patent Document 1).

JP 2005-270862 A

  In the said apparatus, the lump of fats and oils is formed in high concentration fat and oil wastewater, the microorganism sludge in a fat and oil decomposition apparatus becomes difficult to act on fats and oils, and the fats and oils in a fat and oil decomposition apparatus may not fully decompose | disassemble.

  The present invention has been made to solve such problems, and provides a biological wastewater treatment apparatus and a biological wastewater treatment method capable of sufficiently decomposing oil and fat separated from fat and oil-containing wastewater. Objective.

  The biological wastewater treatment device according to the present invention is a biological wastewater treatment device that decomposes organic matter in fat-containing wastewater, and introduces fat-containing wastewater, and separates oil into fat-concentrated fat wastewater and high-concentration fat-oil wastewater. Separation equipment and methane fermentation equipment that introduces low-concentration fat wastewater and performs methane fermentation treatment of low-concentration fat wastewater using microbial sludge, and high-concentration fat drainage using microbial sludge A fat and oil decomposition apparatus for decomposing oil and fat, and the fat and oil decomposition apparatus is a stirrer for stirring high-concentration fat and oil waste introduced into the fat and oil decomposition apparatus and an oil and fat state for acquiring the state of fat and oil in the high-concentration fat and oil waste water It has an acquisition means and a control device that changes the stirring state of the stirring device according to the state of the oil and fat acquired by the fat and oil state acquisition means.

  Further, the biological wastewater treatment method according to the present invention is a biological wastewater treatment method for decomposing organic matter in oil-containing wastewater, wherein the oil-containing wastewater is introduced into an oil concentration separator, and the low-concentration fat wastewater and the high-concentration fats and oils are introduced. Separated into wastewater, introduces low-concentration fat wastewater into methane fermentation equipment, performs methane fermentation treatment of low-concentration fat wastewater using microbial sludge, introduces high-concentration fat wastewater into fat and oil decomposition equipment, and high-concentration fat drainage And microbial sludge are agitated by a stirrer to obtain the state of fat and oil in the high-concentration fat drainage, change the stirring state of the high-concentration fat drainage according to the acquisition result, and decompose the fat and oil in the high-concentration fat drainage It is characterized by doing.

  According to such a biological wastewater treatment device and biological wastewater treatment method, the fat-containing wastewater is separated into the low-concentration fat wastewater and the high-concentration fat wastewater by the fat concentration separation device. Since the low-concentration fat and oil wastewater separated in step 1 is subjected to methane fermentation by the methane fermentation apparatus, the methane fermentation treatment is not inhibited by the fat and oil, the organic matter in the low-concentration fat and oil wastewater is reliably decomposed, and sufficient methane gas is recovered. On the other hand, since the high-concentration fat and oil waste water separated by the fat and oil concentration separation device is introduced into the fat and oil decomposition device and stirred by the stirring device, the formation of fat and oil lump in the high-concentration fat and oil waste water is suppressed. At this time, since the stirring state of the stirring device is changed according to the state of the oil and fat acquired by the oil and fat state acquisition means, the formation of the fat and oil lump in the high-concentration fat and oil waste water is more reliably suppressed. Therefore, the microbial sludge in the oil and fat decomposition apparatus easily acts on the oil and fat, and the oil and fat in the high-concentration waste water is sufficiently decomposed. Thus, since the fat and oil density | concentration of the treated water of a fat and oil decomposition apparatus becomes low enough, the said treated water can be sent to a methane fermentation apparatus, and a methane fermentation process can be performed, without being inhibited by fats and oils. Moreover, when there is little organic substance remaining in the treated water of an oil-and-fat decomposer, it can send to the back | latter stage of a methane fermentation apparatus with the treated water of a methane fermentation apparatus.

  Here, it is preferable that the oil / fat state obtaining means obtains the oil / fat concentration of the high-concentration fat / oil drainage as the state of the fat / oil in the high-concentration fat / oil drainage. In this case, since the state of the fats and oils in the high-concentration fat drainage is acquired based on the easily measured fat and oil concentration, the configuration of the fat and oil state acquisition unit can be simplified.

  Moreover, you may make it a fat-and-oil state acquisition means acquire the magnitude | size of the fat-and-oil particle | grains in high concentration fat-and-oil wastewater as a state of fat and oil in high-concentration fat-and-oil wastewater. In this case, since the formation state of the fat and oil lump is directly measured and the stirring state of the stirring device is changed according to the state, formation of the lump in the high-concentration fat and oil waste water is further reliably suppressed.

  Here, as a configuration that effectively achieves the above-described operation, the oil and fat state acquisition means includes a sampling unit that collects a part of the high-concentration fat drainage in the fat and oil decomposition apparatus, and an image of the high-concentration fat drainage collected by the sampling unit. And an image processing unit that performs image processing on an image captured by the imaging unit to acquire the size of the fat and oil particles.

  Moreover, it is preferable that the microbial sludge used with an oil-and-oil decomposition apparatus has the capability to produce | generate a lipase and decompose a fatty acid. In this case, the fats and oils in the high concentration fat and oil waste water are decomposed with high efficiency and reliability.

  Thus, according to this invention, the fats and oils isolate | separated from the fats and oils containing waste water can fully be decomposed | disassembled.

It is a schematic block diagram of the biological waste water treatment apparatus which employ | adopted the biological waste water treatment method which concerns on 1st Embodiment of this invention. It is a flowchart which shows the control procedure of the control apparatus in FIG. It is a schematic block diagram of the biological waste water treatment apparatus which employ | adopted the biological waste water treatment method which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the control procedure of the control apparatus in FIG.

  Hereinafter, a preferred embodiment of a biological wastewater treatment apparatus employing a biological wastewater treatment method according to the present invention will be described with reference to the accompanying drawings. Note that, in each drawing, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  First, a first embodiment of a biological wastewater treatment apparatus according to the present invention will be described. FIG. 1 is a schematic configuration diagram of a biological wastewater treatment apparatus 100 that employs the biological wastewater treatment method according to the first embodiment of the present invention.

  The biological wastewater treatment device 100 introduces fat-containing wastewater, and separates the oil concentration separator 1 into a low-concentration fat wastewater and a high-concentration fat wastewater, and a methane fermentation device 2 that performs methane fermentation treatment of the low-concentration fat wastewater. And a fat and oil decomposition apparatus 3 for decomposing the fat and oil in the high concentration fat and oil waste water.

  As the fat concentration / separation apparatus 1, for example, a pressure levitation concentration apparatus, an atmospheric pressure levitation concentration apparatus, an API oil trap, or the like can be used.

  The methane fermentation apparatus 2 has a methane fermentation tank 4 and introduces the low-concentration fat / oil drainage separated by the oil concentration / separation apparatus 1 into the methane fermentation tank 4 via the line L1. The methane fermentation tank 4 contains a microbial sludge bed 5 containing microorganisms aggregated in a granular form (here, methane bacteria). The methane bacteria decompose methane gas by decomposing organic matter in the water to be treated under anaerobic conditions. Is generated.

  The methane fermentation apparatus 2 constitutes an EGSB (Expanded Granular Sludge Bed) reaction tank, and raises the low-concentration fat and oil drainage introduced into the methane fermentation tank 4 at a high speed, so that a high-speed upward flow is introduced into the methane fermentation tank 4. Form. The microbial sludge bed 5 flows and expands due to the upward flow in the methane fermentation tank 4, and constitutes a high load state with respect to the low-concentration fat and oil drainage.

  In the upper part of the methane fermentation tank 4, there is provided a gas-solid-liquid separation unit 6 that separates solids such as microorganisms, gas such as methane gas generated in the methane fermentation tank 4, and treated water subjected to methane fermentation treatment. It has been. The methane fermentation apparatus 2 discharges the treated water separated by the gas-solid-liquid separator 6 to the line L2, and discharges the gas to the line L3.

  The fat and oil decomposition apparatus 3 includes an oil and fat decomposition tank 7, a stirring device 11, a gas supply source B 1, an oil and fat state acquisition unit 10, and a control device 9, and the high concentration fat and oil separated by the fat and oil concentration and separation apparatus 1. The waste water is introduced into the fat and oil decomposition tank 7 through the line L5, and oxygen-containing gas is supplied into the fat and oil decomposition tank 7 from the gas supply source B1 through the line L6. In addition, the fats and oils decomposition apparatus 3 may decompose | disassemble fats and oils under anaerobic conditions, without supplying oxygen-containing gas in the fats and oils decomposition tank 7. FIG.

  The fat and oil decomposition tank 7 contains microbial sludge containing a lipase producing bacterium (for example, Acinetobacter genus) and a fatty acid degrading bacterium (for example, Pseudomonas genus, Bacillus genus). Lipase producing bacteria produce lipase under aerobic conditions. Lipase breaks down ester bonds in fats and oils to produce fatty acids. Fatty acid-degrading bacteria degrade fatty acids under aerobic conditions. In addition, the microbial sludge accommodated in the fats-and-oils decomposition tank 7 may contain the microbe (for example, Bacillus genus) which has a property which produces | generates a lipase and decomposes | disassembles a fatty acid.

  A plurality of perforated plates 8 are juxtaposed in the height direction in the fat and oil decomposition tank 7, and each perforated plate 8 is connected to a drive device 26 through a shaft 27 and operates the drive device 26. It is designed to reciprocate up and down. Each of the perforated plates 8 reciprocating up and down collides with high-concentration fat and oil drainage introduced into the fat and oil decomposition tank 7 and forms a turbulent flow in substantially the entire area of the fat and oil decomposition tank 7. Due to this turbulent flow, the high-concentration fat drainage, the microbial sludge and the oxygen-containing gas are agitated. As described above, the perforated plate 8, the drive device 26, and the shaft 27 constitute the stirring device 11 that stirs the high-concentration fat and oil waste introduced into the fat and oil decomposition device 3.

  The oil / fat state acquisition means 10 acquires the oil / fat concentration and the inflow water amount of the high-concentration oil / fat drainage that flows through the line L5 and is introduced into the oil / fat decomposition tank 7 as the state of the oil / fat in the high-concentration fat / oil discharge. For example, an infrared sensor, an odor sensor, or the like can be used to acquire the fat concentration.

  The control device 9 controls the stirring state of the stirring device 11 and the gas supply of the gas supply source B1 based on the information from the oil / fat state acquisition means 10. That is, the control device 9 controls the driving device 26 according to the state of the oil / fat acquired by the oil / fat state acquisition means 10 to change the cycle of the reciprocating motion of the perforated plate 8 and change the stirring state of the stirring device 11. . Further, the control device 9 controls the gas supply amount of the gas supply source B <b> 1 according to the state of the oil / fat acquired by the oil / fat state acquisition means 10, and changes the gas supply amount to the oil / fat decomposition tank 7.

  And the fats-and-oils decomposition apparatus 3 sends the process water by which the fats and oils density | concentration became low by the fats and oils decomposition in the fats and oils decomposition tank 7 to the methane fermentation tank 4 via the line L7.

  Then, the effect | action of the biological waste water treatment apparatus 100 comprised in this way is demonstrated. The fat and oil-containing wastewater is introduced into the fat and oil concentration separator 1 and separated into a low-concentration fat and oil wastewater and a high-concentration fat and oil wastewater. It is introduced into the fermenter 4 and is in countercurrent contact with the microbial sludge bed 5 with high efficiency and is subjected to methane fermentation with high efficiency. The treated water that has been raised in the methane fermentation tank 4 and subjected to methane fermentation is separated from methane gas, microorganisms, and the like by the gas-solid liquid separation unit 6, discharged from the methane fermentation tank 4, and separated by the gas-solid liquid separation unit 6. Gas such as methane gas is discharged out of the methane fermentation tank 4 and recovered as an energy resource.

  On the other hand, the high-concentration fat drainage separated by the fat concentration separation apparatus 1 is introduced into the fat decomposition tank 7 of the fat decomposition apparatus 3, and the microbial sludge in the fat decomposition tank 7 and the oxygen supplied from the gas supply source B1. Mixed with the contained gas. The high-concentration fat and oil drainage, microbial sludge and oxygen-containing gas are sufficiently stirred by the turbulent flow formed by the collision with the perforated plate 8 reciprocating up and down in the fat and oil decomposition tank 7. By this stirring, in the fat and oil decomposition tank 7, formation of fat and oil lump in the high concentration fat and oil waste water is suppressed.

  Here, the control procedure of the stirring state of the stirring device 11 and the gas supply amount of the gas supply source B1 by the control device 9 that makes the feature of the present embodiment particularly, will be described. FIG. 2 is a flowchart showing a control procedure of the control device 9 in FIG. First, the oil / fat state acquisition means 10 acquires the oil / fat concentration and the inflow water amount of the high-concentration oil / fat drainage flowing into the oil / fat decomposition tank 7 (steps S1 and S2). Next, based on the oil concentration and the inflow water amount of the acquired high concentration oil drainage, the oil inflow amount to the oil decomposition tank 7 is calculated (step S3), and there is no change in the oil inflow amount (actually a predetermined value) It is determined whether there is any change described above (step S4). If there is no change in the amount of oil and fat inflow, the reciprocating cycle of the perforated plate 8 and the gas supply amount of the gas supply source B1 are maintained (step S5). On the other hand, if there is a change in the inflow amount of fats and oils, it is determined whether the inflow amount of fats and oils is reduced (step S6). If the oil and fat inflow amount is reduced, the reciprocating cycle of the perforated plate 8 and the gas supply amount of the gas supply source B1 are lowered to save energy consumed by the drive device 26 and the gas supply source B1 (step S7). On the other hand, if the oil inflow amount is increased, the reciprocating cycle of the perforated plate 8 is increased, the increase in the amount of oil and fat mass accompanying the increase in the oil inflow amount is suppressed, and the gas supply amount of the gas supply source B1 is increased. The aerobic reaction of bacteria and fatty acid-degrading bacteria is accelerated, and the decomposition rate of fats and oils is increased (step S8). The control device 9 repeats the above processing at a predetermined cycle.

  Thus, since the stirring state of the stirring device 11 is changed by the control device 9 according to the state of the fats and oils acquired by the fat and oil state acquiring means 10, the formation of the lump of fats and oils in the high concentration fat and oil drainage is more reliable. To be suppressed. Therefore, the microbial sludge in the fat and oil decomposition apparatus 3 easily acts on the fat and oil, and the fat and oil in the high-concentration waste water is sufficiently decomposed.

  The treated water in which the fats and oils are decomposed in the fat and oil decomposition tank 7 is sent to the methane fermentation tank 4. Since the treated water has a sufficiently low fat concentration due to the decomposition of fats and oils, the treated water is subjected to methane fermentation treatment in the methane fermentation tank 4 without being inhibited by the fats and oils. Thereby, more methane gas is collect | recovered in addition to the methane gas collect | recovered by the methane fermentation process of the low concentration fat-oil waste water isolate | separated in the fat concentration separation apparatus 1. FIG.

  Thus, in this embodiment, the fats and oils isolate | separated from the fats and oils containing waste water can fully be decomposed | disassembled.

  Moreover, in this embodiment, the fat and oil concentration and inflow water amount of the high concentration fat and oil wastewater introduced into the fat and oil decomposition tank 7 are acquired as the fat and oil state in the high concentration fat and oil wastewater by the fat and oil state acquisition means 10. Since the oil and fat concentration and the inflow water amount can be easily measured with existing sensors, the configuration of the oil and fat state acquisition means 10 can be simplified. Moreover, since the high concentration fat drainage introduced into the fat decomposition tank 7 is not mixed with the microbial sludge in the fat decomposition tank 7, the fat concentration is easily measured, and the configuration of the fat state acquisition means 10 is further simplified. be able to. In addition, even if the microbial sludge in the fat and oil decomposition tank 7 is mixed with the high-concentration fat and oil waste water, if the measurement of the fat and oil concentration is not hindered, the fat and oil state acquisition means 10 acquires the fat and oil concentration in the fat and oil decomposition tank 7 You may do. In this case, since the fat and oil concentration in the fat and oil decomposition tank 7 can be directly obtained, the stirring state of the stirring device 11 is determined based only on the fat and oil concentration without considering the fluctuation of the amount of water flowing into the fat and oil decomposition tank 7. It may be changed.

  Moreover, since the microbial sludge used with the fats and oils decomposition apparatus 3 has the capability to produce | generate a lipase and to decompose a fatty acid, the fats and oils in high concentration fat and oil waste water are decomposed | disassembled efficiently and reliably.

  Moreover, since the methane fermentation apparatus 2 comprises the EGSB reaction tank, a methane fermentation process can be made high load and a methane fermentation process can be made highly efficient.

  FIG. 3 is a schematic configuration diagram of a biological wastewater treatment apparatus 200 that employs the biological wastewater treatment method according to the second embodiment of the present invention.

  The biological wastewater treatment apparatus 200 of the second embodiment is different from the biological wastewater treatment apparatus 100 of the first embodiment in that the fat and oil state obtaining means 10 for obtaining the fat concentration and inflow water amount of the high concentration fat and oil waste water is obtained. It is the point replaced with the oil-and-fat state acquisition means 24 which acquires the magnitude | size of the oil-and-fat particle | grains in high concentration fat and oil waste water. Accordingly, the control device 9 is also replaced with the control device 25.

  This oil / fat state acquisition means 24 was photographed by a sampling unit 21 that collects a part of the high-concentration fat / oil drainage in the fat / oil decomposition tank 7, and an imaging unit 22 that captures an enlarged image of the collected high-concentration fat / oil drainage. And an image processing unit 23 that performs image processing on the enlarged image and acquires the size of the fat and oil particles.

  The control device 25 changes the stirring state of the stirring device 11 and the gas supply amount of the gas supply source B1 according to the size of the fat and oil particles acquired by the fat and oil state acquisition unit 24. FIG. 4 is a flowchart showing a control procedure of the control device 25 in FIG. First, the fat and oil state acquisition means 24 acquires the size of the fat and oil particles in the high-concentration fat and oil wastewater introduced into the fat and oil decomposition tank 7. That is, a part of the high-concentration fat drainage in the fat / oil decomposition tank 7 is sampled by the sampling unit 21 (step S21), and an enlarged image of the collected high-concentration fat drainage is taken by the imaging unit 22 (step S22). Then, the image processing unit 23 performs image processing on the captured enlarged image to acquire the size of the oil and fat particles (step S23). Next, it is determined whether the size of the fat and oil particles is equal to or smaller than a predetermined size (here, 100 μm) (step S24). If the size of the fat and oil particles is 100 μm or less, the reciprocating cycle of the perforated plate 8 and the gas supply amount of the gas supply source B1 are set to be smaller than predetermined values, and the energy consumption of the driving device 26 and the gas supply source B1 is saved. (Step S25). On the other hand, if the size of the particles is larger than 100 μm, the reciprocating cycle of the porous plate 8 is set to be larger than a predetermined value, and the increase in fat and oil mass is suppressed, and the gas supply amount of the gas supply source B1 is less than the predetermined value. Is set to a large value to increase the decomposition speed of the oil (step S26). The control device 25 repeatedly performs the above processing at a predetermined cycle.

  Thus, in this embodiment, the size of the fat particles in the high-concentration fat drainage is acquired as the state of the fats and oils in the high-concentration fat drainage by the fat state acquisition means 24, and the formation of a lump of fats and oils The state is obtained directly. And since the stirring state of the stirring apparatus 11 is changed according to the formation state of the lump of fats and oils acquired directly, formation of the lump in high concentration fat and oil wastewater is suppressed more reliably.

  Moreover, although the fats and oils decomposition apparatus 3 is sending the treated water to the methane fermentation tank 4, when the organic substance density | concentration of treated water is very low, it seems to send to the back | latter stage of the methane fermentation apparatus 2 with the treated water of the methane fermentation apparatus 2. Anyway.

  The stirring device 11 includes the perforated plate 8, the drive device 26, and the shaft 27. The stirring blades (for example, propeller blades, paddle blades, turbine blades, anchor blades) installed in the oil decomposition tank 7 and You may be comprised by the power source. In this case, it is preferable to increase the rotation speed of the stirring blade instead of increasing the reciprocation period of the porous plate 8 and decrease the rotation speed of the stirring blade instead of decreasing the reciprocation period of the porous plate 8.

  The methane fermentation tank 4 constitutes an EGSB reaction tank. However, it only needs to constitute a reaction tank that decomposes organic substances by anaerobic reaction to generate methane gas. For example, UASB (Upflow Anaerobic Sludge Blanket) You may comprise the reaction tank.

  DESCRIPTION OF SYMBOLS 1 ... Oil and fat concentration separation apparatus, 2 ... Methane fermentation apparatus, 3 ... Oil and fat decomposition apparatus, 9 ... Control apparatus, 10 ... Oil and fat state acquisition means, 11 ... Stirrer, 100 ... Biological waste water treatment apparatus.

Claims (6)

In biological wastewater treatment equipment that decomposes organic matter in oil-containing wastewater,
An oil and fat concentrating and separating apparatus that introduces the oil and fat-containing waste water and separates into a low-concentration fat and oil waste water and a high-concentration fat and oil waste water,
A methane fermentation apparatus that introduces the low-concentration fat wastewater and performs methane fermentation treatment of the low-concentration fat wastewater using microbial sludge;
An oil and fat decomposition apparatus that introduces the high-concentration fat drainage and decomposes fats and oils in the high-concentration fat drainage using microbial sludge,
The fat and oil decomposer includes a stirring device that stirs the high-concentration fat and oil wastewater introduced into the fat and oil decomposer, an oil and fat state acquisition unit that acquires the state of the fat and oil in the high-concentration fat and oil wastewater, and the fat and oil state acquisition. A biological wastewater treatment apparatus comprising: a control device that changes a stirring state of the stirring device in accordance with the state of the oil and fat obtained by the means.   2. The biological wastewater treatment apparatus according to claim 1, wherein the fat and oil state obtaining unit obtains the fat and oil concentration of the high-concentration fat and oil wastewater as the state of the fat and oil in the high-concentration fat and oil wastewater.   2. The biological wastewater treatment according to claim 1, wherein the fat and oil state obtaining unit obtains the size of the fat and oil particles in the high concentration fat and oil wastewater as the state of the fat and oil in the high concentration fat and oil wastewater. apparatus.   The fat and oil state acquisition means includes a sampling unit that collects a part of the high-concentration fat drainage in the fat and oil decomposition apparatus, an imaging unit that captures an image of the high-concentration fat drainage collected by the sampling unit, and The biological wastewater treatment apparatus according to claim 3, further comprising: an image processing unit that performs image processing on the image captured by the imaging unit to acquire the size of the fat and oil particles.   The biological effluent treatment apparatus according to any one of claims 1 to 4, wherein the microbial sludge used in the fat and oil decomposition apparatus has an ability to generate lipase and decompose fatty acids. In a biological wastewater treatment method for decomposing organic matter in oil-containing wastewater,
The fat and oil containing wastewater is introduced into a fat and oil concentration separator, and separated into a low concentration fat wastewater and a high concentration fat wastewater,
The low-concentration fat wastewater is introduced into a methane fermentation apparatus, and the low-concentration fat wastewater is subjected to methane fermentation using microbial sludge,
The high-concentration fat / oil wastewater is introduced into a fat / oil decomposition apparatus, the high-concentration fat / oil drainage and the microbial sludge are stirred by a stirrer, the state of the fat / oil in the high-concentration fat / oil drainage is obtained, and according to the acquisition result A biological wastewater treatment method, wherein the agitation state of the high-concentration fat drainage is changed to decompose the fats and oils in the high-concentration fat drainage.

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