JP6654981B2 - Anaerobic treatment of organic wastewater - Google Patents

Description

  The present invention relates to an anaerobic treatment method for organic wastewater, and in particular, reduces the start-up operation period until an anaerobic microorganism is attached to a non-biological carrier to form a highly active biofilm on the surface of the non-biological carrier. The present invention relates to an anaerobic treatment method for organic wastewater.

  Methods of treating organic wastewater using microorganisms include aerobic biological treatment and anaerobic biological treatment. Among anaerobic biological treatments, methane fermentation treatment is a biological treatment method that uses the metabolic reaction of anaerobic microorganisms that grow in an oxygen-free anaerobic environment to decompose organic matter in organic wastewater into methane gas or carbon dioxide gas. Compared to aerobic biological treatment, there is an advantage that the amount of generated sludge is small, and there is no running cost because electricity costs such as a blower (aeration) are unnecessary, and the generated methane gas can be used effectively. In recent years, it has been particularly noted as a method for treating organic wastewater.

  As the methane fermentation treatment method, for example, a UASB (abbreviation of Upflow Anaerobic Sludge Blanket), a fixed bed method, a fluidized bed method and the like are known. Above all, the UASB method uses granule sludge formed by granulation by contact of anaerobic bacteria such as methane bacteria and acid-producing bacteria with sludge, thereby reducing the concentration of methane bacteria in the reaction tank. It has the feature that it can be maintained at a high concentration, and as a result, it can be efficiently treated even when the concentration of organic matter in the wastewater is considerably high. Therefore, it is widely used in Japan and overseas as a method for treating organic wastewater. However, there is a problem that it is difficult to form and maintain granule sludge in organic wastewater discharged from a chemical factory or the like and mainly composed of low molecular organic substances such as methanol and formaldehyde.

When COD _Cr (oxygen demand by potassium dichromate) is 2000 mg / L or less of low concentration raw water, COD _Cr volume load, which is a design load in a general UASB treatment method, is 10 kg / (m ³ · When the operation is performed in d), the flow rate of the organic wastewater becomes excessive, and the linear velocity (LV) in the UASB reactor exceeds 3 m / h, so that granular sludge flows out of the UASB reactor. In addition, it becomes difficult to maintain the amount of sludge in the UASB reaction tank.

  As a measure to maintain the required amount of sludge in the UASB reaction tank, granule sludge is placed in the UASB reaction tank with the non-biological carrier and the methane bacteria granules present in a volume ratio of 100: 5 to 100: 500. A start-up operation method for starting the flow of organic wastewater has been proposed (Patent Document 1). However, since it takes time for the methane bacteria granules to adhere to the non-biological carrier and form a biofilm, the granule sludge is dismantled before the biofilm is formed on the non-biological carrier, and methane bacteria flow out. Therefore, in order to secure the required amount of methane bacteria granules at the time of steady operation, it is necessary to supply a large amount of granular sludge at the start of water supply.

  The carrier and the methane bacteria aggregate obtained by pulverizing the methane bacteria granules are charged into the reaction tank, and the start-up operation of the reaction tank is performed in a state where the methane bacteria aggregate per 1 L of the carrier is present in the range of 1 to 900 g. (Patent Document 2). However, since the methane bacterium granules are pulverized, the sedimentation speed is reduced and the sedimentation speed is liable to flow out of the reactor, and the desired amount of sludge cannot be maintained during the start-up operation. It is necessary to input a large amount of methanogen granules in consideration of the amount.

  Granule sludge is formed as a sludge layer in UASB (upflow anaerobic sludge bed method) and EGSB (expanded sludge bed method). Normal granule sludge has a structure in which filamentous or rod-shaped Methanosaeta methanogens are intertwined. Furthermore, the extracellular polymer secreted from acid-producing bacteria maintains high mechanical strength. In addition, in the case of an upward-flow type reaction tank such as UASB or EGSB having a solid-liquid separation mechanism, the introduced granular sludge can be retained, but in the complete mixing type reaction tank, the granular sludge flows out in a short period of time. I will.

Japanese Patent No. 568902 JP 2014-100680 A

An object of the present invention is to provide an anaerobic treatment method for organic wastewater in which the startup operation period of an anaerobic reaction tank is shortened.
Another object of the present invention is to provide an anaerobic treatment method for organic wastewater, which can reduce the necessity of maintaining and managing the amount of sludge according to the load fluctuation.

The embodiments of the present invention are as follows.
[1] An anaerobic treatment method for treating organic wastewater by passing organic wastewater through an anaerobic reaction tank holding a carrier capable of supporting anaerobic microorganisms,
At the start of the passage of the organic wastewater, a compatible carrier to which anaerobic microorganisms are attached and a new carrier to which anaerobic microorganisms are not mixed are mixed, and the compatible carrier is 5 vol% or more and less than 100 vol% of all the carriers. An anaerobic treatment method for organic wastewater, characterized in that:
[2] The anaerobic treatment of the organic wastewater according to [1], wherein the adaptable carrier is a carrier to which anaerobic microorganisms having an SS per bulk volume of the carrier of 1 g / L to 500 g / L are adhered. Method.
[3] The organic wastewater according to [1] or [2], wherein the conditioned carrier is a carrier conditioned in an existing anaerobic reactor and / or a carrier conditioned in a temporary anaerobic reactor. Anaerobic treatment method.
[4] an anaerobic reaction tank holding a carrier capable of supporting anaerobic microorganisms;
An anaerobic reaction tank for preparing a conditioned carrier to which a anaerobic microorganism for attaching to the anaerobic reaction tank is attached,
An anaerobic treatment apparatus for organic wastewater, comprising:

  According to the anaerobic treatment method of the organic wastewater of the present invention, a biofilm having high methane generation activity is easily formed on the surface of the carrier because the anaerobic microorganism is attached to the familiar carrier. Can be shortened.

  Moreover, even in a complete mixing type reaction tank (including a mechanical stirring type and a gas stirring type) in which granulated sludge flows out in a short time, the familiar carrier is difficult to flow out, so it depends on the type of anaerobic reaction tank. The start-up period can be shortened without the need.

  Furthermore, according to the organic wastewater treatment method of the present invention, it is possible to prevent the granular sludge from flowing out at the time of load change or the like, so that it is possible to reduce the necessity of maintaining and managing the amount of sludge according to the load change.

It is explanatory drawing which illustrated the outline | summary of one form of the organic wastewater treatment method of this invention. It is explanatory drawing which shows an example of a schematic structure of an upward flow methane fermentation tank as an anaerobic reaction tank. It is explanatory drawing which shows another example of a schematic structure of an upward flow methane fermentation tank as an anaerobic reaction tank. It is explanatory drawing which shows another example of a schematic structure of a mechanical stirring type methane fermentation tank as an anaerobic reaction tank. It is explanatory drawing which shows another example of a schematic structure of a gas stirring type methane fermentation tank as an anaerobic reaction tank. It is a schematic diagram of normal granule sludge. It is a schematic diagram of a conforming carrier. 6 is a graph showing the change over time of the S-COD _Cr removal rates of Comparative Examples 1 and 2. It is a graph which shows the daily change of S-COD _Cr removal rate of Examples 1-5.

Embodiment

  FIG. 1 is an explanatory view illustrating an outline of one embodiment of the anaerobic treatment method for organic wastewater of the present invention. In FIG. 1, raw water (organic wastewater) is treated in an acid fermentation treatment tank, then introduced into a methane fermentation tank and subjected to anaerobic treatment, and the resulting treated water is sent to a treatment water tank. The treated water from the treated water tank may be returned to the acid fermentation tank and / or the methane fermentation tank and used for controlling the upward flow rate in the tank.

  The methane fermentation tank is an anaerobic fluidized bed upward flow type reaction tank that holds anaerobic microorganisms on the surface of a fluid carrier (FIGS. 2 to 3), a mechanical stirring type complete mixing tank (FIG. 4), and a gas stirring type. A complete mixing tank (FIG. 5) or the like can be used. In the anaerobic reaction tank (methane fermentation tank), biogas (methane gas) generated by the anaerobic reaction rises in the anaerobic reaction tank and is discharged from the upper part of the anaerobic reaction tank to the outside to be collected. At this time, the carrier holding the microorganisms may rise together and flow out of the anaerobic reaction tank as overflow. In the case of a complete mixing tank, the biogas is forcibly raised by mechanical stirring or gas stirring, so that the carrier often rises. In the apparatus for practicing the present invention, a screen for separating the treated water and the carrier is provided at the overflow in order to prevent the carrier from flowing out of the anaerobic reaction tank (methane fermentation tank) (FIG. 2). Alternatively, an overflow water storage unit is attached to the outside of the anaerobic reaction tank, the overflow water including the carrier is temporarily stored, a screen is provided at an outlet from the overflow water storage unit, and the carrier and the treated water are separated. It may be configured to return only the anaerobic reaction tank (FIG. 3). The biogas recovered from the anaerobic reaction tank (methane fermentation tank) can be used in a boiler or the like after performing gas purification such as desulfurization as necessary.

The present invention is characterized in that the start-up operation of an anaerobic reaction tank (methane fermentation tank) is controlled. Usually, in the anaerobic treatment of organic wastewater, it is necessary to carry out the anaerobic microorganism acclimatization operation until the design load of the anaerobic reaction tank is reached. Since it takes a long time for stable attachment and propagation of microorganisms to a new carrier, the start-up operation time may exceed 90 days. In the present invention, at the start of the passage of the organic wastewater, the familiar carrier to which the anaerobic microorganisms have already adhered is mixed in an amount of 5 vol% or more and less than 100 vol% of the total carrier amount, thereby shortening the startup operation period.

The method for anaerobic treatment of organic wastewater of the present invention is an anaerobic treatment method in which organic wastewater is passed through an anaerobic reaction tank holding a carrier capable of supporting anaerobic microorganisms for treatment. At the start of the flow of the anaerobic wastewater, the adaptable carrier to which the anaerobic microorganisms are attached and the new carrier to which the anaerobic microorganisms are not attached are mixed, and the adaptable carrier is set to 5 vol% or more and less than 100 vol% of all the carriers. It is characterized by doing.

  The anaerobic reaction tank in the present invention is anaerobic in all temperature ranges, such as a medium-temperature methane fermentation treatment tank with an optimum temperature of 30 ° C to 40 ° C, and a high-temperature methane fermentation treatment tank with an optimum temperature of 50 ° C to 60 ° C. The treatment tank can be used without limitation.

[Operation conditions of anaerobic reaction tank (methane fermentation tank)]
When the anaerobic reaction tank (methane fermentation tank) is an upward anaerobic reaction tank, LV is preferably 1 m / h or more and 20 m / h or less, particularly preferably 2 m / h or more and 10 m / h or less. In order to adjust the inside of the anaerobic reaction tank (methane fermentation tank) to a predetermined LV, a part of the anaerobic reaction (methane fermentation) treated water is supplied to the lower part of the anaerobic reaction tank (methane fermentation tank). Can be circulated to the water inlet. The treated water to be circulated may be treated water containing no carrier after passing treated water accompanied by a carrier flowing out of an anaerobic reaction tank (methane fermentation tank) through a screen to separate the carrier, or a treatment containing a carrier. It may be water. When circulating treated water containing a carrier, it is preferable to use a snake pump or a gas lift that does not destroy the carrier. When the carrier is separated, it is preferable to return the carrier to the anaerobic reaction tank (methane fermentation tank) (FIG. 3).

Design loading anaerobic reactor (methane fermentation tank) _{(COD Cr} volumetric loading) depends on the raw water properties, but can range from ^{5~50kg / (m 3 · d)} . Granule sludge floats with bubbles inside, or granule sludge may be dismantled due to excessive gas mixing, so high-load treatment is difficult. Thus, higher load processing can be performed.

Generally, granular sludge contains not only methane-producing bacteria but also acid-producing bacteria, and has high activity near the surface but low activity at the center (FIG. 6). On the other hand, in the familiar carrier used in the present invention, highly active methane-producing bacteria adhere to the carrier surface in a dominant state (FIG. 7). The methane generation activity of general granule sludge is 0.4 to 0.8 kg COD _Cr / (kg-SS · d), but the methane generation activity of the microorganisms supported on the carrier used in the present invention is 1%. 0.0 to 4.0 kg COD _Cr / (kg-SS · d)

  In determining the load condition of the methane fermentation tank, the CODCr load per sludge amount based on MLVSS (hereinafter referred to as “sludge load”) is 1 to 4 kg / (kg-MLVSS) based on the adhered sludge of the familiar carrier.・ Adjust the load so that d).

[Carrier]
The carrier can be used without any particular limitation as long as the carrier can support the microorganism and propagate the microorganism on the surface of the carrier.

  The shape of the carrier may be any shape such as a sphere, a column, a rectangular parallelepiped, and a hollow, but the amount of microorganisms supported, the efficiency of contact between the propagated microorganisms and organic wastewater, and the amount of carrier retained in the anaerobic reaction tank In view of the above, a spherical shape is particularly preferable.

  The size of the carrier is preferably 0.1 mm or more and 10 mm or less, more preferably 2 mm or more as an average value (median diameter d50 for spherical particles, arithmetic mean value of the maximum and minimum dimensions for other shapes). It is preferably 6 mm or less.

  The carrier is preferably a porous carrier having pores to which microorganisms can easily adhere, and the pore diameter is preferably 1 μm or more and 100 μm or less, particularly preferably 5 μm or more and 50 μm or less.

  Further, in order to make the fluid flow in the anaerobic reaction tank, fresh water is flowed upward into a cylindrical column having a diameter of 80 mm filled with unused carrier at an ascending linear velocity (LV) of 1 m / h to 20 m / h. Expansion rate when passing water (carrier height when passing water relative to carrier height when charged) is 105% or more and 150% or less, especially 110% or more when water is passed when LV is 2 m / h or more and 15 m / h or less. Carriers that are less than 130% are preferred.

  The material of the carrier may be any material as long as anaerobic microorganisms adhere thereto. However, activated carbon, polyvinyl alcohol, ethylene glycol, and the like are particularly preferable because the above-mentioned requirements are satisfied.

[Compatible carrier]
In the present invention, at the start-up operation of the anaerobic reaction tank, that is, at the start of the flow of the organic wastewater, the familiar carrier is mixed in the anaerobic tank reactor together with the new carrier. The amount of the familiar carrier to be mixed is 5 vol% or more and less than 100 vol%, preferably 20 vol% or more and less than 100 vol% of the total carrier amount. If the mixing ratio of the conforming carrier is too small, the startup operation period becomes long.

The adaptable carrier is a carrier having anaerobic microorganisms or methane-producing bacteria of a type that easily forms a biofilm on the surface of the above-described carrier, and it is preferable that methane-producing bacteria be in a dominant state. The amount of anaerobic microorganisms attached to the carrier is 1 g / L or more and 500 g / L or less, preferably 5 g / L or more and 100 g / L or less as SS per bulk volume of the carrier. The SS measures the nitrogen content and the phosphorus content combined with the carrier by using the values measured by peeling the microorganisms attached to the surface of the carrier, and the empirical chemical composition formula (C ₅ H ₇ O) of the anaerobic microorganism. ₂ NP _0.06 S _0.1 )). If the attached amount is small, the time required for the anaerobic reaction tank to reach the design load cannot be shortened even if the familiar carrier is charged during the start-up operation of the anaerobic reaction tank. The proportion of bacteria increases, and the efficiency of attachment of anaerobic microorganisms to the new carrier decreases.

  It is preferable to use a carrier that has been adapted in an existing anaerobic reaction tank and / or a temporary anaerobic reaction tank. The existing anaerobic reaction tank refers to an anaerobic reaction tank that is already performing a steady-state operation in a water treatment facility that is the same as or different from the anaerobic reaction tank in which the startup operation is to be performed. The temporary anaerobic reaction tank refers to a small anaerobic reaction tank whose purpose is to provide a carrier that is compatible with the anaerobic reaction tank to be started up. Seed sludge and a new carrier are immersed in the same organic wastewater as the treatment target of the anaerobic reaction tank that is going to perform the start-up operation, the seed sludge is attached to the carrier, and the seed sludge is propagated on the carrier surface. And a compatible carrier carrying an anaerobic microorganism. A small-sized anaerobic treatment device is required to prepare a carrier, so long as it can prevent the carrier and the seed sludge from flowing out. Carrier separation such as a UASB type reaction tank equipped with a gas-solid liquid separation device, a screen, etc. Any type such as a complete mixing type reaction tank having a function, an anaerobic membrane separation device having a separation membrane inside or outside the reaction tank, or a batch methane fermentation tank may be used. When a temporary small anaerobic treatment device is used, during the installation work of the anaerobic reaction tank to be started up, the familiar carrier can be prepared in a separate reaction tank in parallel, There is also an advantage that the raising operation period can be significantly reduced. Alternatively, when there is no anaerobic treatment device capable of supplying a suitable adaptation carrier, the carrier may be immersed in a water tank of an existing water treatment device for treating organic wastewater to be treated. There is not a small amount of methanogen in such a tank. As a condition of the water tank in which the carrier is immersed, a reduced state in which the oxidation-reduction potential is -200 mV or less is preferable. Examples of such a water tank include a raw water storage tank, a treated water tank, and an excess sludge storage tank, and an excess sludge storage tank having a particularly high anaerobic level and a high sludge concentration is preferable.

[Organic wastewater]
The COD _{Cr of the} organic wastewater that can be treated by the anaerobic treatment method of the present invention is not particularly limited, and the organic wastewater having an organic substance concentration in a range from 100 mg / L to 50,000 mg / L of low to high concentration. Can be applied to In the case of organic wastewater having a high organic matter concentration, it is preferable to appropriately dilute the wastewater in order to alleviate the inhibition of the raw water components.

  The anaerobic treatment method of the present invention is particularly useful for treating organic wastewater having a composition that cannot maintain granular sludge. For example, organic wastewater containing low-molecular-weight organic substances having 5 or less carbon atoms, such as ethanol, methanol, and acetic acid, which cannot maintain the granular sludge due to reduced strength of the granular sludge, and a pipe cleaning agent that dismantles the granular sludge. It is effective for treating organic wastewater from beverage factories containing chelating agents, bactericides and the like.

FIG. 1 shows a process flow in which organic wastewater flows into a methane fermentation tank after an acid fermentation treatment in an acid fermentation tank, but the acid fermentation treatment is not essential. It is not necessary to use an acid fermenter in the case of organic wastewater in which acid fermentation has already progressed sufficiently, or organic wastewater that can be treated only in a methane fermenter without performing acid fermentation. Specifically, for example, and organic wastewater total COD _Cr equivalent value of 5 or less organic acid carbon to organic wastewater COD _Cr occupies 40% or more, a low molecular organic material having one carbon atom such as methanol or formaldehyde In the case of the organic wastewater which accounts for 70% or more of the organic wastewater COD _Cr , the acid fermentation treatment is unnecessary. In the case of performing the acid fermentation treatment, the pH is adjusted with an alkali agent in the acid fermenter so that the pH becomes 5.5 or more, which is suitable for the acid-producing bacteria. By circulating the methane fermentation treated water to the acid fermentation tank, the amount of alkali agent added can be reduced by the alkali component contained in the methane fermentation treated water. The residence time of the acid fermentation tank can be appropriately determined in the range of 2 hours to 48 hours depending on the components contained in the organic wastewater. Often.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
In Comparative Examples and Examples, organic wastewater (raw water), which is a soft drink factory wastewater whose COD _Cr was adjusted to about 3,000 mg / L, was treated with an alkaline solution such that the residence time was 6 hours, the water temperature was 36 ° C, and the pH was 6.5. After adding sodium hydroxide as an agent and performing an acid fermentation treatment, a 10-liter upward flow anaerobic reaction tank or a mechanical stirring type complete mixing reaction tank using a paddle (hereinafter, both are collectively referred to as a “methane fermentation tank”) ) Was used for anaerobic treatment. A screen having a width of 2.0 mm was provided in the treated water outflow portion above the methane fermentation tank to prevent the carrier from flowing out of the methane fermentation tank. A part of the methane fermentation treatment water was circulated to the inflow portion at the lower part of the methane fermentation tank, and the LV of the methane fermentation tank was adjusted to 5.0 m / h.

Gel particles of polyvinyl alcohol having an average particle diameter of 4.0 mm, an LV of 10 m / h in an unused fresh water test and an expansion rate of 115% were used as a carrier.
The design load of the methane fermentation tank was set to 20 kg / (m ³ · d), and the comparative example and the example were operated at a COD _Cr volume load of 10 kg / (m ³ · d) for 14 days, and thereafter, the COD _Cr volume load was 20 kg / (m ³ · d). and continue operation at the m ³ · d).

In the evaluation of the treatment performance, soluble COD _Cr (S-COD _Cr ) of a 1 μm filtrate was employed in order to remove the influence of the sludge flowing out.
[Comparative Example 1]
4.0 L of granular sludge and 4.0 L of unused fresh carrier were added to the upward flow type reaction tank at a time, and the flow of acid fermentation treatment water was started. As the granular sludge, granule sludge having a particle diameter of 0.5 mm to 2.0 mm and a ratio of 92%, which was collected from UASB in a steady operation in which the same raw water was subjected to acid fermentation treatment water, was used.

COD _Cr volume loading of the setting load 20kg / ^(m 3 · d) and the 15 day after, with granular sludge flows out in a short time, _{S-COD Cr} removal rate decreased. When the operation was continued, the S-COD _Cr removal rate was stabilized at about 90% after the 68th day. As a result, the startup operation period was 68 days.

[Comparative Example 2]
4.0 L of granular sludge and 4.0 L of unused fresh carrier were added at a time to the mechanical stirring type complete mixing reaction tank, and the flow of acid fermentation treatment water was started. As the granular sludge, granule sludge having a particle diameter of 0.5 mm to 2.0 mm and a ratio of 92%, which was collected from UASB in a steady operation in which the same raw water was subjected to acid fermentation treatment water, was used.

Immediately after the start-up operation started, the granular sludge flowed out in a short time, and the S-COD _Cr removal rate decreased. When the operation was continued, the S-COD _Cr removal rate was stabilized at about 90% after the 88th day. As a result, the startup operation period was 88 days.

[Example 1]
0.4 L of the familiar carrier and 3.6 L of an unused new carrier were charged into the upward flow type reaction tank, and the flow of the acid fermentation treated water was started. As an adaptable carrier, an unused carrier was charged into an anaerobic reaction tank for treating the same raw water in the acid fermentation treatment water, and after a steady operation for half a year, the adapted carrier (SS per bulk volume of the carrier was 53 g / L) was used.

Although the removal rate of S-COD _Cr was low after the start of operation, it gradually increased and stabilized at about 90% after the 36th day. As a result, the startup operation period was 36 days.
[Example 2]
2.0 L of the familiar carrier and 2.0 L of an unused new carrier were charged into the upward flow type reaction tank, and the flow of the acid fermentation treated water was started. As an adaptable carrier, an unused carrier was charged into an anaerobic reaction tank for treating the same raw water in the acid fermentation treatment water, and after a steady operation for half a year, the adapted carrier (SS per bulk volume of the carrier was 53 g / L) was used.

Setting load of COD _Cr volumetric loading 20kg / ^(m 3 · d) and the 15 day onwards, have been reduced _{S-COD Cr} removal rate was stable at about 90% after 24 days. As a result, the startup operation period was 24 days.

[Example 3]
0.4 L of the familiar carrier and 3.6 L of an unused new carrier were charged into the upward flow type reaction tank, and the flow of the acid fermentation treated water was started. As a compatible carrier, a surplus sludge discharged from a water treatment facility of a soft drink factory and an unused new carrier are charged into a plastic tank and adjusted for 3 months. Used 6 g / L).

Although the removal rate of S-COD _Cr was low after the start of the operation, it gradually increased and stabilized at about 90% after the 46th day. As a result, the startup operation period was 46 days.
[Example 4]
0.4 L of the familiar carrier and 3.6 L of an unused new carrier were charged into the upward flow type reaction tank, and the flow of the acid fermentation treated water was started. Granular sludge having a particle diameter of 0.5% to 2.0mm and a ratio of 92% collected from a UASB in a steady operation in which the same raw water is subjected to acid fermentation treatment water is used as the matching carrier. , And a batch-type batch methane fermentation for one week was used for three months to prepare a conventional carrier (SS per bulk volume of the carrier was 46 g / L).

COD _Cr volumetric loading 20kg / ^(m 3 · d) and the 15 days after, but _{S-COD Cr} removal rate decreased and stabilized at approximately 90% after 39 days. As a result, the startup operation period was 39 days.

[Example 5]
0.4 L of the familiar carrier and 3.6 L of an unused new carrier were charged into a mechanical stirring type complete mixing reaction tank, and the flow of acid fermentation treated water was started. As an adaptable carrier, an unused carrier was charged into an anaerobic reaction tank for treating the same raw water in the acid fermentation treatment water, and after a steady operation for half a year, the adapted carrier (SS per bulk volume of the carrier was 53 g / L) was used.

Setting load of COD _Cr volumetric loading 20kg / ^(m 3 · d) and the 15 day onwards, have been reduced _{S-COD Cr} removal rate was stable at about 90% after 38 days. As a result, the startup operation period was 38 days.

  The results for Comparative Examples and Examples are summarized in Table 1, FIGS. 8 and 9.

Claims (4)

An anaerobic treatment method for passing organic wastewater through an anaerobic reaction tank holding a carrier capable of supporting anaerobic microorganisms, and treating the wastewater.
At the start of the passage of the organic wastewater, a compatible carrier to which anaerobic microorganisms are attached and a new carrier to which anaerobic microorganisms are not mixed are mixed, and the compatible carrier is 5 vol% or more and less than 100 vol% of all carriers. and,
The acclimatization carrier is a carrier which anaerobic microorganisms and methanogenic bacteria easily type forming a biofilm on the surface of the carrier is attached, and wherein the carrier der Rukoto methanogens are dominant state Anaerobic treatment method for organic wastewater. The method for anaerobic treatment of organic wastewater according to claim 1, wherein the adaptable carrier is a carrier to which anaerobic microorganisms having an SS per bulk volume of the carrier of 1 g / L to 500 g / L are adhered. The anaerobic treatment method for organic wastewater according to claim 1 or 2, wherein the adaptation carrier is a carrier adapted in an existing anaerobic reaction tank and / or a carrier adapted in a temporary anaerobic reaction tank. An anaerobic fluidized bed anaerobic reaction tank holding anaerobic microorganisms on the surface of a fluid carrier ,
An anaerobic reaction tank for preparing a conditioned carrier to which a anaerobic microorganism and a methane-producing bacterium are attached to be introduced into the anaerobic reaction tank, and is a UASB type equipped with a gas-solid liquid separation device. Small anaerobic treatment selected from reaction tank, complete mixing type reaction tank with carrier separation function, anaerobic membrane separation device with separation membrane inside or outside the reaction tank, and batch methane fermentation tank An apparatus, or an anaerobic reaction tank for a preparation carrier preparation, which is a water tank of an existing water treatment apparatus selected from a storage tank of raw water in a reduced state having an oxidation-reduction potential of -200 mV or less, a treated water tank, and an excess sludge storage tank,
An anaerobic treatment apparatus for organic wastewater, comprising: