JP2017154082A - Anaerobic wastewater treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anaerobic wastewater treatment device having enhanced destruction efficiency of higher fatty acid in an anaerobic treatment.SOLUTION: There is provided an anaerobic wastewater treatment device having an acid production tank for introducing wastewater containing oil and fat and producing primary treated water containing acid by decomposing the oil and fat by treatment bacteria and a reaction tank for introducing the primary treated water, methane fermenting by the treatment bacteria to produce secondary treatment water and including a return means for returning the treatment bacteria ejected from the reaction tank to the acid production tank and/or a hydrogen partial pressure reduction means for reducing hydrogen partial pressure in the acid production tank.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an anaerobic wastewater treatment apparatus.

  As a method of treating wastewater containing fats and oils, for example, wastewater containing fats and oils is separated into oil and water by pressurized flotation, separated into sludge containing fats and oils and pressurized flotation treated water, and then pressurized flotation treated water is preferred. A method of applying methane fermentation by methane bacteria to decomposition of sludge containing fats and oils is known (Patent Document 1). According to the method of Patent Document 1, oil and fat in waste water containing fat and oil is separated, and anaerobic treatment is applied to the decomposition of the fat and oil-containing sludge after separation, thereby purifying waste water containing fat and oil with high efficiency. ing.

JP 2006-95377 A

  On the other hand, the method of Patent Document 1 may cause problems such as generation of odor due to pressurization and the need for a space associated with the introduction of the pressurization tank. In addition, fats and oils have a problem that they are difficult to biodegrade under anaerobic treatment conditions. In particular, higher fatty acids produced by hydrolyzing ester bonds of fats and oils (triglycerides) are not easily reduced in molecular weight by β-oxidation under anaerobic treatment conditions, and lower fatty acids that can be decomposed to methane by methane bacteria are produced. There is a problem that it is difficult. Furthermore, there is a problem that scum is generated due to accumulation of higher fatty acids in the tank.

  Then, an object of this invention is to provide the anaerobic waste water treatment apparatus which raised the decomposition | disassembly efficiency of the higher fatty acid in anaerobic treatment.

  That is, the present invention introduces wastewater containing fats and oils, decomposes fats and oils with treated bacteria to produce primary treated water containing acids, and introduces primary treated water and ferments methane with treated fungi. A reaction tank for generating secondary treated water, and a return means for returning treated bacteria discharged from the reaction tank to the acid generation tank and / or a hydrogen partial pressure reduction means for reducing the hydrogen partial pressure in the acid generation tank. An anaerobic waste water treatment apparatus is provided.

  According to the anaerobic waste water treatment apparatus according to the present invention, the decomposition efficiency of higher fatty acids in the anaerobic treatment can be increased.

  The present inventors speculate as follows why the higher fatty acid decomposition efficiency in the anaerobic treatment can be increased by the anaerobic wastewater treatment apparatus according to the present invention. First, in this invention, by having the return means which returns the process microbe discharged | emitted from a reaction tank to an acid production tank, decomposition | disassembly of the fats and oils and higher fatty acid by the returned process microbe is accelerated | stimulated in an acid production tank. Furthermore, it is considered that β oxidation of higher fatty acids in the acid generation tank is promoted because the hydrogen partial pressure in the acid generation tank can be reduced by the returned treated bacteria.

  In the present invention, the hydrogen partial pressure reducing means for reducing the hydrogen partial pressure in the acid generation tank can be used to reduce the hydrogen partial pressure. The inventors speculate.

  In addition, according to the anaerobic wastewater treatment apparatus according to the present invention, wastewater containing fats and oils is not separated by oil and water by pressurized flotation, and odor is generated and a space associated with introduction of a pressurized flotation tank is required. There is no problem.

  The return means may include a collection unit that collects the treated bacteria to be discharged.

  The hydrogen partial pressure reducing means may be a dominating means for dominating bacteria that use hydrogen in the acid generation tank, and the dominating means is in an acid generating tank containing bacteria that use hydrogen. It may be a means for giving a load fluctuation to the treated bacteria or a means for supplying a substance that inhibits the activity of the treated bacteria in the acid production tank other than the bacteria utilizing hydrogen.

  ADVANTAGE OF THE INVENTION According to this invention, the anaerobic waste water treatment apparatus which improved the decomposition | disassembly efficiency of the higher fatty acid in anaerobic processing can be provided.

It is a schematic diagram which shows the anaerobic waste water treatment apparatus which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the anaerobic waste water treatment apparatus which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows the anaerobic waste water treatment apparatus which concerns on 3rd Embodiment of this invention. It is a schematic diagram which shows the anaerobic waste water treatment apparatus which concerns on 4th Embodiment of this invention. It is a schematic diagram which shows an example of the collection part in the anaerobic waste water treatment apparatus which concerns on 5th Embodiment of this invention. It is a schematic diagram which shows an example of the collection part in the anaerobic waste water treatment apparatus which concerns on 6th Embodiment of this invention. It is a schematic diagram which shows the anaerobic waste water treatment apparatus which concerns on 7th Embodiment of this invention. It is a schematic diagram which shows the anaerobic waste water treatment apparatus which concerns on 8th Embodiment of this invention. It is a schematic diagram which shows the anaerobic waste water treatment apparatus which concerns on 9th Embodiment of this invention. It is a figure which shows the breakdown of the oil component in the acid production tank which concerns on each embodiment of this invention, and its decomposition product.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings depending on cases, but the invention is not limited to these embodiments.

[Anaerobic wastewater treatment equipment]
The anaerobic wastewater treatment apparatus according to the present embodiment introduces wastewater containing fats and oils, decomposes fats and oils with treated bacteria to produce primary treated water containing acids, and introduces primary treated water and treats them. A reaction tank that produces methane-fermented methane-fermented secondary treatment water, and returns the treatment bacteria discharged from the reaction tank to the acid generation tank and / or reduces the hydrogen partial pressure in the acid generation tank It has a hydrogen partial pressure reducing means.

  In this embodiment, the anaerobic treatment is a treatment to hydrolyze fats and oils to produce higher fatty acids, a treatment to produce higher fatty acids by β-oxidation of higher fatty acids, and conversion of lower fatty acids to methane and carbon dioxide by methane fermentation or the like. The process to do. Here, the higher fatty acid refers to, for example, a fatty acid having 12 or more carbon atoms, and the lower fatty acid refers to, for example, a fatty acid having 2 to 4 carbon atoms such as acetic acid.

  In the present embodiment, the acid generation refers to a treatment for hydrolyzing fats and oils to produce higher fatty acids and, optionally, β-oxidation of higher fatty acids to produce lower fatty acids. In addition, the present inventors have confirmed that wastewater containing fats and oils is decomposed by the treatment bacteria in the acid generation tank. FIG. 10 shows the result of measuring the content ratios of fats and oils (triglycerides), higher fatty acids and lower fatty acids before and after the cultivation after adding fats and oils, treated bacteria and medium in a nitrogen-substituted test tube and culturing for 72 hours. Indicates. According to FIG. 10, the return means for returning the treated bacteria discharged from the reaction tank to the acid generation tank and / or the hydrogen partial pressure reduction means for reducing the hydrogen partial pressure in the acid generation tank, It can be seen that the percentage can be increased.

  The treated bacteria may be any anaerobic bacteria suitable for anaerobic treatment, for example, methane bacteria such as methanobacterium, methanospirillum, and methanosarcina, sulfate-reducing bacteria such as desulfobibrio, clostridium, and symphophomonas. Can be mentioned. The treated bacteria may be used singly or in a mixed form. The method for adding the treated bacteria to the acid production tank and the reaction tank is not particularly limited, and the treated bacteria may be added as it is, a granule sludge layer containing the treated bacteria may be added, and it is immobilized on the carrier. Treated bacteria may be added. Moreover, the structure of the processing microbe accommodated in an acid production tank and a reaction tank may be the same or different.

<First Embodiment>
FIG. 1 is a schematic diagram showing an anaerobic wastewater treatment apparatus according to the first embodiment of the present invention. An anaerobic waste water treatment apparatus 100 shown in FIG. 1 includes an acid generation tank 10, a reaction tank 20, a return means 30 for returning treated bacteria discharged from the reaction tank 20 to the acid generation tank, and a line L1 connecting them. To L5.

  Waste water containing fats and oils is introduced into the acid generation tank 10 via the line L1, and is acid-treated by the treatment bacteria accommodated in the acid generation tank 10 to generate primary treated water. The primary treated water contains at least a lower fatty acid, but may contain other higher fatty acids and untreated fats and oils. Subsequently, the primary treated water is introduced into the reaction tank 20 via the line L2, and methane-fermented by the treatment bacteria accommodated in the reaction tank 20 to generate a gas 23 mainly composed of methane and carbon dioxide, Generate secondary treated water. Moreover, the processing microbe accommodated in the reaction tank 20 may form the granule sludge layer 22, for example. Note that a settler 21 may be provided inside the reaction vessel 20. The generated gas 23 is released outside the apparatus (not shown). The secondary treated water is discharged out of the reaction tank 20 through the line L3 and introduced into the return means 30. The secondary treated water contains a part of the treated bacteria stored in the reaction tank 20. The return means 30 collects at least a part of the treated bacteria, and the treated bacteria are returned to the acid generation tank 10 via the line L4. A valve V1 may be provided in the line L4. The treated bacteria returned to the acid generation tank 10 may be returned as granules when the granular sludge layer 22 is formed in the reaction tank 20, or separated by ultrasonic waves, jetting, in-pump crushing, or the like. It may be returned in a state where it has been fixed, or it may be returned in a state where it is immobilized on a carrier. In order to immobilize the treated bacterium on a carrier, it may be cultured for a certain period in a culture solution containing the carrier. The remaining secondary treated water introduced into the return means 30 is discharged out of the apparatus via the line L5.

  Thus, in the anaerobic waste water treatment apparatus 100, the amount of treated bacteria in the acid production tank 10 is increased by including the return means 30 for returning the treated bacteria discharged from the reaction tank 20 to the acid production tank. The decomposition of fats and oils and higher fatty acids in the acid generation tank 10 (and in some cases the reaction tank 20) is promoted. In particular, the capacity of bacteria (methanobacteria, etc.) using hydrogen is increased, and the hydrogen partial pressure in the acid generation tank 10 (and in some cases, the reaction tank 20) is reduced. Thereby, β oxidation of higher fatty acids is promoted, and the decomposition efficiency of higher fatty acids in the anaerobic treatment can be increased.

(Second to Fourth Embodiments)
FIGS. 2-4 is a schematic diagram which shows the anaerobic waste water treatment apparatus which concerns on 2nd-4th embodiment of this invention, It is equipped with an acid production | generation tank and a reaction tank, The hydrogen partial pressure in an acid production tank is shown It has a hydrogen partial pressure reducing means for reducing. The hydrogen partial pressure reducing means may be a dominating means for dominating bacteria that use hydrogen in the acid generation tank. Making the bacteria using hydrogen dominant means that bacteria using hydrogen become the dominant species in the entire treated bacteria. The dominating means for dominating the bacteria using hydrogen in the acid generation tank may be, for example, a means for giving load fluctuations to the acid generation tank containing bacteria using hydrogen and the treatment bacteria in the reaction tank. Further, it may be a means for supplying a substance that inhibits the activity of the treatment bacteria in the acid generation tank and reaction tank other than the bacteria using hydrogen. Here, examples of the bacteria using hydrogen include hydrogen-utilizing methane bacteria such as methanobacterium and methanospirillum, and hydrogen-utilizing sulfate-reducing bacteria such as desulfobibrio.

  Substances that inhibit the activity of acid-producing tanks other than bacteria that use hydrogen and the treatment bacteria in the reaction tank, act on the acid-producing tanks other than bacteria that use hydrogen and the treated bacteria themselves in the reaction tank, Substances that inhibit the activity of the treatment bacteria in the acid production tank and the reaction tank other than the bacteria that use hydrogen by controlling the pH in the reaction solution in the acid production tank and the reaction tank in an alkaline environment, etc. . Examples of the substance that acts on the acid producing tank other than the bacteria using hydrogen and the treated bacteria themselves in the reaction tank to suppress the activity include methanol, sulfur compounds, ammonium nitrogen, ammonia and the like. In addition, as a substance that inhibits the activity of the treatment bacteria in the acid production tank and the reaction tank other than the bacteria that use hydrogen by making the pH in the reaction solution in the acid production tank and the reaction tank in an alkaline environment, Examples include alkaline substances such as sodium and potassium hydroxide. In the case of using an alkaline substance, in the reaction of decomposing oils and fats to generate acid, the activity of treated bacteria other than bacteria using hydrogen is efficiently suppressed while inhibiting the inhibition of the activity of bacteria using hydrogen. From the viewpoint of inhibiting the pH of the reaction solution, the pH in the reaction solution is preferably controlled to 7.5 to 8.0, and more preferably 7.5 to 7.8.

  FIGS. 2 and 3 are schematic views showing an anaerobic wastewater treatment apparatus in the case where the dominating means is a means for giving load fluctuations to the acid generation tank containing bacteria utilizing hydrogen and the treatment bacteria in the reaction tank ( Second Embodiment and Third Embodiment). Giving load fluctuations to acid generation tanks containing bacteria that use hydrogen and treatment bacteria in reaction tanks means that treatment bacteria containing bacteria that use hydrogen treat organic substances such as fats and oils that are processed per unit time and unit volume. This refers to changing the amount, for example, increasing and decreasing the amount of organic matter such as fats and oils, and repeating these steps. In addition, the present inventors have confirmed that methanobacterium can be dominant by giving a load fluctuation to the treated bacteria.

Second Embodiment
An anaerobic wastewater treatment apparatus 200 shown in FIG. 2 stores an acid generation tank 10, a reaction tank 20, a high-concentration raw water tank 40 that stores wastewater containing high-concentration fats and oils, and wastewater that contains low-concentration fats and oils. The low concentration raw | natural water tank 50 and the line L2 and L6-L10 which connect these are provided.

  Wastewater containing fats and oils is divided into wastewater containing high-concentration fats and fats and wastewater containing low-concentration fats and oils, and is introduced into the high-concentration raw water tank 40 and the low-concentration raw water tank 50 through lines L6 and L8, respectively. . Wastewater containing high-concentration oil and fat and low-concentration oil and fat respectively stored in the high-concentration raw water tank 40 and the low-concentration raw water tank 50 are introduced into the acid generation tank 10 via lines L7 and L9, respectively. . At this time, the lines L7 and L9 are provided with valves V2 and V3 as switching means, respectively, and the oil and fat concentration in the raw water can be changed by switching the valves V2 and V3. For example, when introducing wastewater containing high-concentration oil into the acid generation tank 10, the valve V2 may be opened and the valve V3 may be closed. The waste water containing the high-concentration or low-concentration oil and fat introduced into the acid generation tank 10 is acid-treated by the treatment bacteria accommodated in the acid generation tank 10 to generate primary treated water. The primary treated water contains at least a lower fatty acid, but may contain other higher fatty acids and untreated fats and oils. Subsequently, the primary treated water is introduced into the reaction tank 20 via the line L2, and methane-fermented by the treatment bacteria accommodated in the reaction tank 20 to generate a gas 23 mainly composed of methane and carbon dioxide, Generate secondary treated water. The treated bacteria accommodated in the reaction tank 20 may form a granular sludge layer 22. The generated gas is discharged out of the apparatus (not shown). The secondary treated water is discharged through the line L10.

<Third Embodiment>
The anaerobic waste water treatment apparatus 300 shown in FIG. 3 includes an acid generation tank 10, a reaction tank 20, a raw water tank 60 that stores waste water containing fats and oils, and lines L2, L5, and L11 to L13 that connect these. Prepare.

  Waste water containing fats and oils is introduced into the raw water tank 60 via the line L11. Waste water containing fats and oils stored in the raw water tank 60 is introduced into the acid generation tank 10 via the line L12. The waste water containing fats and oils introduced into the acid generation tank 10 is acid-treated by the treatment bacteria accommodated in the acid generation tank 10 to generate primary treated water. The primary treated water contains at least a lower fatty acid, but may contain other higher fatty acids and untreated fats and oils. Subsequently, the primary treated water is introduced into the reaction tank 20 through the line L2, and generates a gas 23 mainly composed of methane and carbon dioxide that has been methane-fermented by the treatment bacteria accommodated in the reaction tank 20, Generate secondary treated water. The treated bacteria accommodated in the reaction tank 20 may form a granular sludge layer 22. The generated gas 23 is released outside the apparatus (not shown). The secondary treated water is introduced so that at least a part thereof joins the line L12 via the line L13. At this time, a valve V4 is provided in the line L13, and the fat and oil concentration in the raw water can be changed by opening / closing control of the valve V4. For example, when making the fats and oils in the waste water containing the fats and oils introduced into the acid generation tank 10 into a low concentration, the valve V4 may be opened. The remainder of the secondary treated water is discharged through line L5.

  Note that the line L13 does not necessarily have to be introduced so as to merge with the line L12 as described above, and can achieve the purpose of adjusting the concentration of the oil and fat in the wastewater including the oil and fat introduced into the acid generation tank 10. For example, it may be introduced so as to join the raw water tank 60. Moreover, the line L13 should just be able to supply the water which does not contain fats and oils to raw | natural water, does not necessarily need to be connected with the line L5, and may be connected with supply ports, such as industrial water.

  Thus, in the anaerobic waste water treatment apparatus 200 and 300, by changing the fat and oil content of the waste water containing the fat and oil introduced into the acid generation tank 10 with time, the treated bacteria including bacteria using hydrogen are treated. On the other hand, by giving a load fluctuation, bacteria (methanobacterium, etc.) using hydrogen dominate, and the hydrogen partial pressure in the acid generation tank 10 (and the reaction tank 20) is reduced. Thereby, β oxidation of higher fatty acids is promoted, and the decomposition efficiency of higher fatty acids in the anaerobic treatment can be increased.

<Fourth embodiment>
FIG. 4 is a schematic diagram showing an anaerobic wastewater treatment apparatus when the dominant means is means for supplying a substance that mainly inhibits the activity of treated bacteria in an acid generation tank and reaction tank other than bacteria using hydrogen. FIG. By mainly inhibiting the activity of treated bacteria other than bacteria that use hydrogen, bacteria that use hydrogen are relatively dominant, and the hydrogen partial pressure in the acid generation tank and reaction tank is reduced.

  The anaerobic wastewater treatment apparatus 400 shown in FIG. 4 includes an acid generation tank 10, a reaction tank 20, an inhibitor supply tank 70, and lines L1 to L2, L5, and L14 that connect them.

  Waste water containing fats and oils is introduced into the acid generation tank 10 via the line L1, and is acid-treated by the treatment bacteria accommodated in the acid generation tank 10 to generate primary treated water. At this time, a substance that mainly inhibits the activity of treatment bacteria other than the bacteria that use hydrogen is supplied to the acid generation tank 10 from the inhibitor supply tank 70 via the line L14. A valve V5 may be provided in the line L14. The primary treated water contains at least a lower fatty acid, but may contain other higher fatty acids and untreated fats and oils. Subsequently, the primary treated water is introduced into the reaction tank 20 via the line L2, and methane-fermented by the treatment bacteria accommodated in the reaction tank 20 to generate a gas 23 mainly composed of methane and carbon dioxide, Generate secondary treated water. The treated bacteria accommodated in the reaction tank 20 may form a granular sludge layer 22. The generated gas 23 is released outside the apparatus (not shown). Secondary treated water is discharged via line L5.

  Thus, in the anaerobic waste water treatment apparatus 400, by introducing a substance that inhibits the activity of treatment bacteria other than bacteria that use hydrogen into the acid generation tank 10, bacteria that use hydrogen eventually dominate. Thus, the hydrogen partial pressure in the acid generation tank 10 (and the reaction tank 20) is reduced. Thereby, β oxidation of higher fatty acids is promoted, and the decomposition efficiency of higher fatty acids in the anaerobic treatment can be increased.

(Fifth and sixth embodiments)
In the anaerobic wastewater treatment apparatus 100 according to the first embodiment, the return means 30 preferably includes a collection unit that collects the discharged processing bacteria. Since the return means 30 includes a collection unit that collects the treated bacteria, the treated bacteria contained in the secondary treated water can be efficiently collected. Therefore, the amount of treated bacteria in the acid generation tank 10 can be more effectively reduced. Can be increased. As a collection part, a U-shaped valve, a buffer tank, etc. are mentioned, for example. FIG.5 and FIG.6 is a schematic diagram which shows the collection part in the anaerobic waste water treatment apparatus which concerns on 1st Embodiment of this invention.

<Fifth Embodiment>
FIG. 5 is a schematic diagram showing the U-shaped valve 31, and a valve V6 is provided at the bottom of the U-shaped tube. In the anaerobic wastewater treatment apparatus 100, the treated bacteria contained in the secondary treated water supplied via the line L3 are collected by the U-shaped valve 31 and returned to the acid generation tank 10 via the line L4. The secondary treated water from which the treated bacteria have been separated may be drained through, for example, the line L5, or may be returned to the acid generation tank 10 through the line L4 together with the treated bacteria.

<Sixth Embodiment>
FIG. 6 is a schematic diagram showing the buffer tank 32. The treated bacteria contained in the secondary treated water supplied via the line L3 are precipitated and collected in the buffer tank 32, and returned to the acid generation tank 10 via the line L4. The secondary treated water from which the treated bacteria have been separated may be drained through, for example, the line L5, or may be returned to the acid generation tank 10 through the line L4 together with the treated bacteria.

<Seventh embodiment>
FIG. 7 is a schematic view showing an anaerobic waste water treatment apparatus according to the seventh embodiment of the present invention. An anaerobic waste water treatment apparatus 700 shown in FIG. 7 includes an acid generation tank 10, a reaction tank 20, a return means 30 for returning treated bacteria discharged from the reaction tank 20 to the acid generation tank, and high-concentration fats and oils. The high concentration raw | natural water tank 40 which stores waste_water | drain, the low concentration raw | natural water tank 50 which stores the waste_water | drain containing low concentration fats and oils, and the lines L2-L9 which connect these are provided.

  In the anaerobic wastewater treatment apparatus 700, the amount of treated bacteria in the acid production tank 10 is increased by providing the return means 30 for returning the treated bacteria discharged from the reaction tank 20 to the acid production tank. The decomposition of fats and oils and higher fatty acids in the (and reaction tank 20 in some cases) is promoted. In particular, the capacity of bacteria (methanobacteria, etc.) using hydrogen is increased, and the hydrogen partial pressure in the acid generation tank 10 (and in some cases, the reaction tank 20) is reduced. In addition, by changing the oil content of the wastewater containing fats and oils introduced into the acid generation tank 10, a load fluctuation is given to the treated bacteria containing bacteria that use hydrogen, and as a result, bacteria that use hydrogen Is dominant, and the hydrogen partial pressure in the acid generation tank 10 (and the reaction tank 20) is reduced. Thereby, β oxidation of higher fatty acids is promoted, and the decomposition efficiency of higher fatty acids in the anaerobic treatment can be increased.

<Eighth Embodiment>
FIG. 8 is a schematic view showing an anaerobic waste water treatment apparatus according to the eighth embodiment of the present invention. An anaerobic wastewater treatment apparatus 800 shown in FIG. 8 stores an acid generation tank 10, a reaction tank 20, a return means 30 for returning treated bacteria discharged from the reaction tank 20 to the acid generation tank, and wastewater containing fats and oils. Raw water tank 60, and lines L2 to L5 and L11 to L13 connecting them.

  In the anaerobic wastewater treatment apparatus 700, the amount of treated bacteria in the acid production tank 10 is increased by providing the return means 30 for returning the treated bacteria discharged from the reaction tank 20 to the acid production tank. The decomposition of fats and oils and higher fatty acids in the (and reaction tank 20 in some cases) is promoted. In particular, the capacity of bacteria (methanobacteria, etc.) using hydrogen is increased, and the hydrogen partial pressure in the acid generation tank 10 (and in some cases, the reaction tank 20) is reduced. In addition, by changing the oil content of the wastewater containing fats and oils introduced into the acid generation tank 10, a load fluctuation is given to the treated bacteria containing bacteria that use hydrogen, and as a result, bacteria that use hydrogen Is dominant, and the hydrogen partial pressure in the acid generation tank 10 (and the reaction tank 20) is reduced. Thereby, β oxidation of higher fatty acids is promoted, and the decomposition efficiency of higher fatty acids in the anaerobic treatment can be increased.

<Ninth Embodiment>
FIG. 9 is a schematic view showing an anaerobic waste water treatment apparatus according to the ninth embodiment of the present invention. An anaerobic waste water treatment apparatus 900 shown in FIG. 9 includes an acid generation tank 10, a reaction tank 20, a return means 30 that returns treated bacteria discharged from the reaction tank 20 to the acid generation tank, and an inhibitor supply tank 70. , Lines L1 to L5 and L14 connecting them.

  In the anaerobic waste water treatment apparatus 900, the amount of the treatment bacteria in the acid production tank 10 increases by providing the return means 30 for returning the treatment bacteria discharged from the reaction tank 20 to the acid production tank. The decomposition of fats and oils and higher fatty acids in the (and reaction tank 20 in some cases) is promoted. In particular, the capacity of bacteria (methanobacteria, etc.) using hydrogen is increased, and the hydrogen partial pressure in the acid generation tank 10 (and in some cases, the reaction tank 20) is reduced. In addition, by introducing a substance that inhibits the activity of treated bacteria other than bacteria that use hydrogen from the inhibitor supply tank 70 to the acid generation tank 10, the bacteria that use hydrogen eventually become dominant, and acid generation occurs. The hydrogen partial pressure in the tank 10 (and the reaction tank 20) is reduced. Thereby, β oxidation of higher fatty acids is promoted, and the decomposition efficiency of higher fatty acids in the anaerobic treatment can be increased.

  100, 200, 300, 400, 700, 800, 900 ... anaerobic waste water treatment device, 10 ... acid generation tank, 20 ... reaction tank, 21 ... settler, 22 ... granule sludge layer, 23 ... gas, 30 ... return means 31 ... U-shaped valve, 32 ... Buffer tank, 40 ... High concentration raw water tank, 50 ... Low concentration raw water tank, 60 ... Raw water tank, 70 ... Inhibitor substance supply tank, L1, L2, L3, L4, L5, L6 L7, L8, L9, L10, L11, L12, L13, L14 ... lines, V1, V2, V3, V4, V5 ... valves.

Claims (5)

An acid generation tank that introduces wastewater containing fats and oils, decomposes the fats and oils with treated bacteria to produce primary treated water containing acids,
A reaction vessel for introducing the primary treated water, producing methane fermented with the treated bacteria to produce secondary treated water,
An anaerobic wastewater treatment apparatus comprising return means for returning treated bacteria discharged from the reaction tank to the acid generation tank and / or hydrogen partial pressure reduction means for reducing hydrogen partial pressure in the acid generation tank.   The anaerobic wastewater treatment apparatus according to claim 1, wherein the return means includes a collection unit that collects the discharged treated bacteria.   The anaerobic wastewater treatment apparatus according to claim 1, wherein the hydrogen partial pressure reducing means is a dominant means for predominating bacteria that use hydrogen in the acid generation tank.   The anaerobic waste water treatment apparatus according to claim 3, wherein the dominating means is a means for giving a load fluctuation to the treatment bacteria in the acid generation tank containing the bacteria that utilize the hydrogen.   The anaerobic waste water treatment apparatus according to claim 3, wherein the dominating means is means for supplying a substance that inhibits the activity of the treatment bacteria in the acid generation tank other than the bacteria utilizing the hydrogen.

Images