JPH05138192A - Anaerobic treatment of high-concentration organic waste water containing organic suspended solid and equipment thereof - Google Patents

Abstract

PURPOSE:To enhance the degree of decomposition of organic suspended solid by washing the organic suspended solid with treated water and performing liquid-solid separation to separate the same into supernatant and concentrate and treating supernatant by a high efficient anaerobic bioreactor and treating condensate by a device combined with a floating type bioreactor and a membrane separator, CONSTITUTION:Drainage containing organic suspended solid at high concentration in a raw liquid tank 1 is sent to a washing tank 3, washed and separated into organic suspended solid and liquid. Organic suspended solid difficult to be decomposed is removed by a filter member 4. Then filtrate is sent to a liquid-solid separator 6 and separated into supernatant 6b and concentrate 6a. Supernatant 6b is treated at high load by using a high efficient anaerobic bioreactor 12 such as a fluidized bed reactor. Concentrate 6a is treated by a floating type bioration membrane and a precision filtration membrane. Thereby the degree of decomposition of organic substance is enhanced because the concentration of suspended solid is low in the high efficient anaerobic bioreactor 12.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an organic suspended substance (S
The present invention relates to a method and an apparatus for anaerobically treating wastewater containing S) in a high concentration.

[0002]

2. Description of the Related Art Conventionally, in order to anaerobically treat wastewater containing a high concentration of organic suspended solids (SS), UASB (Upfl
ow Anaeiohic Sladge Blanket (sludge bed), fluidized bed, fixed bed and other highly efficient anaerobic bioreactors have been developed.

[0003]

However, whichever treatment method is used, high-concentration organic suspensions represented by, for example, shochu wastewater, brewer's yeast washing wastewater, sake rinsing wastewater, starch wastewater, etc. are used. When the substance (SS) is included, it cannot be granulated (UASB), the biofilm is separated (fluidized bed), the filter bed is blocked (fixed bed), and the organic suspended substance (SS) is short-passed. It cannot be processed because the removal rate deteriorates.

Further, when a completely mixed floating type bioreactor is used, the processing speed is slow, and therefore a huge bioreactor is required. Organic suspended solids (SS) flow out without being decomposed and dehydrated sludge. There was a problem that the amount was very large.

Moreover, the organic suspended solids (SS) contained in these wastewaters account for 10 to 50% of the organic matter in the wastewater, have a very high viscosity, and can be concentrated and dehydrated at low cost. Is difficult.

The present invention has been made to solve such conventional problems, and an object thereof is to perform solid-liquid separation of waste water containing an organic suspended solid (SS) in a high concentration. , Separate into a supernatant liquid containing a relatively small concentration of organic suspended solids (SS) and a concentrated liquid containing a high concentration of organic suspended solids (SS), and subject them individually to anaerobic treatment An object of the present invention is to provide a method and an apparatus for anaerobic treatment of highly concentrated organic wastewater containing an organic suspended substance (SS) that enables the above.

[0007]

A method for anaerobic treatment of high-concentration organic wastewater containing organic suspended solids according to claim 1, wherein the wastewater containing high-concentration organic suspended solids is washed and solidified. Liquid-separated, the solid-liquid separated supernatant is supplied to the anaerobic bioreactor and processed by methane fermentation, and the solid-liquid separated organic suspended substance is a floating type with a membrane separator. It is supplied to the anaerobic bioreactor of the above and treated by methane fermentation.

The anaerobic treatment method for high-concentration organic wastewater containing organic suspended solids according to claim 2 is to wash wastewater containing organic suspended solids in high concentration with treated water or diluted water. is there. The method for anaerobic treatment of high-concentration organic wastewater containing organic suspended matter according to claim 3, wherein the high-concentration organic wastewater containing organic suspended matter is shochu distilled water, brewer's yeast washing according to claim 1. It is waste water, rice rinsing waste water of sake, and starch waste liquor.

According to a fourth aspect of the present invention, there is provided an anaerobic treatment method for high-concentration organic wastewater containing an organic suspended substance, wherein the wastewater containing an organic suspended substance in a high concentration is washed to obtain 300 μm.
It removes organic suspended matter of m or more.

According to a fifth aspect of the present invention, there is provided an anaerobic treatment apparatus for high-concentration organic wastewater containing organic suspended solids, which comprises a stock solution tank for storing wastewater containing high-concentration organic suspended solids and an organic suspension tank. A washing device for washing wastewater containing a high concentration of turbid substances, a solid-liquid separation device, an anaerobic bioreactor that takes in the supernatant of the solid-liquid separation device and processes it by methane fermentation, and concentration of the solid-liquid separation device Equipped with a floating type anaerobic bioreakly that takes in wastewater containing a high concentration of the suspended organic suspended matter and treats it by methane fermentation, and a membrane separation device that connects with the floating type anaerobic bioreakly It is a thing.

According to a sixth aspect of the present invention, there is provided an anaerobic treatment apparatus for high-concentration organic wastewater containing organic suspended matter, which is the cleaning apparatus for washing wastewater containing high-concentration organic suspended matter. Is provided with a filtering member for removing organic suspended matter of 300 μm or more.

According to a seventh aspect of the present invention, in the anaerobic treatment apparatus for high-concentration organic wastewater containing organic suspended matter, the floating type anaerobic bioreactor and the membrane separation apparatus in the fifth aspect are provided. The circulation device is interposed.

[0013]

The organic suspending substance according to claim 1 (S
S) In the anaerobic treatment method of high-concentration organic wastewater containing, the wastewater containing high concentration of organic suspended solids (SS) is washed, and the concentration of organic suspended solids (SS) is relatively low. The supernatant and the concentrated liquid containing a high concentration of organic suspended solids (SS) are separated, and the supernatant containing a relatively small concentration of organic suspended solids (SS) is transferred to the anaerobic bioreactor. It is supplied and processed by methane fermentation, and a concentrated liquid containing a high concentration of organic suspended solids (SS) is supplied to a floating type anaerobic bioreactor having a membrane separation device and processed by methane fermentation. ..

In the method for anaerobic treatment of high-concentration organic wastewater containing organic suspended solids (SS) according to claim 4, the wastewater containing high-concentration organic suspended solids (SS) is washed, For example, potato peels, roots, trunks, etc.
Remove organic suspended solids (SS) above 0 μm.

In the anaerobic treatment apparatus for high-concentration organic wastewater containing organic suspended solids (SS) according to claim 5, the organic suspended solids (SS) stored in the stock solution tank are contained in high concentration. The wastewater is washed with a washing device, and in the solid-liquid separation device, a supernatant containing a relatively small concentration of organic suspended solids (SS) and a concentrated liquid containing a high concentration of organic suspended solids (SS) Separated into and
A supernatant containing a relatively low concentration of organic suspended solids (SS) is processed by methane fermentation in an anaerobic bioreactor to obtain a concentrated liquid containing a high concentration of organic suspended solids (SS). , A floating type anaerobic bioreactor and methane fermentation, and a membrane separation device.

In the anaerobic treatment apparatus for high-concentration organic wastewater containing organic suspended solids (SS) according to claim 6, 30
An organic suspended substance (SS) of 0 μm or more is removed by a filter member.

In the anaerobic treatment apparatus for high-concentration organic wastewater containing organic suspended solids (SS) according to claim 7, a concentrated liquid containing high-concentration organic suspended solids (SS) is suspended. Type anaerobic bioreactor is used for methane fermentation, and the membrane is separated by a membrane separator.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows an embodiment of an anaerobic treatment apparatus for high-concentration organic wastewater containing an organic suspended substance according to the present invention, and 1 is a stock solution tank.

The stock solution tank 1 stores waste water containing high-concentration organic suspended substances (SS) represented by, for example, shochu waste water, brewer's yeast washing waste water, sake rinsing waste water, starch waste liquid, and the like. It The stock solution tank 1 is connected to the cleaning device 3 via a pipe 2.

The cleaning device 3 has, for example, a diameter of 0.5 mm.
A filtering member 4 for removing large organic suspended solids (SS) of 300 μm or more is provided, such as a punching plate having a large number of small holes, a filter, and a screen. In addition, the cleaning device 3 has an organic suspended substance (S
Well water or circulating water is supplied in order to sufficiently separate S) from waste water. The well water or circulating water required for that purpose is from undiluted to about 100 times, depending on the properties of the waste water. The setting of the dilution ratio is determined by the viscosity of the waste water and should be 10 cP or less. The cleaning device 3 is connected via a pipe 5 to a solid-liquid separation device 6 composed of an SS concentration tank.

As the solid-liquid separator 6, a sedimentation tank or a centrifuge is used. In this solid-liquid separator 6, an organic suspended substance (SS) having a relatively large particle size and having a sedimentation velocity of 1 m / hour or more is transferred to the concentrated liquid 6a side, and the suspended liquid 6b is discharged toward the supernatant liquid 6b. Only a light organic suspended solid (SS) with a sedimentation speed of 1 m / hour or less is used. At this time, the concentration of the organic suspended substance (SS) in the concentrated liquid is controlled to 50,000 mg / l or less. The solid-liquid separation device 6 communicates with the supernatant liquid storage tank 8 via a pipe 7 and also communicates with the floating bioreactor 10 via a pipe 9.

The supernatant storage tank 8 is in communication with the anaerobic bioreactor 12 via a pipe 11. As the anaerobic bioreactor 12, a UASB that allows a high load
(Upflow Anaeiohic Sladge Blanket) (sludge bed) type reactor, fluidized bed type reactor, or fixed bed fluidized bed type reactor is used. In this example, a fluidized bed reactor is shown. Further, in the anaerobic bioreactor 12, the supernatant liquid is circulated through the pipe 13. It is necessary to install a precipitation tank in this circulation line and control the concentration of the organic suspended solids (SS) in the circulation liquid to be 3,000 mg / l or less.

The anaerobic bioreactor 12 uses the UASB (Upflow Anaei) depending on the CODcr concentration of the supernatant liquid when undiluted.
Either an ohic sludge blanket (sludge bed) type reactor, a fluidized bed type reactor, or a fixed bed fluidized bed type reactor is used.

By the way, the supernatant CODcr concentration is 6,000 m
In the case of g / l or less, UASB is used and the circulation ratio of the reactor is 0-10. The supernatant CODcr concentration is 6,
In the case of 000-15,000 mg / l, a fixed bed is used and the circulation ratio of the reactor is 10-20. Supernatant CODcr
When the concentration is 15,000 mg / l, a fixed bed is used and the circulation ratio of the reactor is 20-100.

Here, a part or all of the generated circulating liquid is used as circulating water for cleaning the cleaning device 3. The concentration of organic suspended solids (SS) when diluted is 1,000 mg / l.
It is desirable to control the following.

In UASB, the upward flow velocity is 1 m /
Even if the organic suspended solids (SS) cannot be decomposed by setting the time more than the time, the organic suspended solids (SS) will remain on the treated water side.
Is controlled to flow out of the system so as not to affect the reaction. In the case of the other reactors, the upward flow velocity is higher than 1 m / hour, so that there is almost no influence of organic suspended solids (SS).

Further, the BOD load can be expected to be 5 kg-BOD / m ³ / day or more, and the BOD efficiency can be expected to be 85%. Further, the anaerobic bioreactor 12 is connected to the biofilm separation tank 15 via the pipe 14 and to the gas holder 17 via the pipe 16. Also, the biofilm separation tank 15
Pipes 18 and 19 for removing treated water and excess sludge are attached to the pipes. Further, a pipe 20 for taking out methane gas is attached to the gas holder 17.

On the other hand, in the floating bioreactor 10,
A circulating water tank 22 is connected via a pipe 21. A cross-flow type membrane separator 24 using an ultrafiltration membrane or a microfiltration membrane is connected to the circulating water tank 22 via pipes 23 and 25. A pipe 28 for taking out the separated treated water is attached to the membrane separation device 24. Further, in the circulating water tank 22, a return path is connected to the floating bioreactor 10 via pipes 26 and 29. Furthermore, in the floating bioreactor 10,
The sludge is drawn out through the pipes 27 and 29. Furthermore, the floating bioreactor 10 has a pipe 3
The generated gas is sent to the gas holder 17 via 0. In this floating type bioreactor 10, the decomposition of organic suspended solids (SS) is slow, so the BOD load is set to about 1 to 5 kg / m ³ / day. In the floating bioreactor 10, the sludge concentration in the floating bioreactor 10 is 30,000 mg / l by pulling out the sludge.
Control to the following. Further, a part or all of the sludge circulating liquid used for cleaning the membrane surface is used for stirring and mixing the floating bioreactor 10 at a membrane surface flow velocity of 0.2 m / sec or more. When the mixing is insufficient only by stirring with the circulating liquid, air lift stirring with the generated gas of the floating bioreactor 10 is also used. Normally, this operation results in a BOD removal rate of 95%
The above can be expected.

Next, the organic suspended substance (SS) of the present invention
An anaerobic treatment method for high-concentration organic wastewater containing the above will be described with reference to FIG. First, waste water containing a high concentration of organic suspended substances in the stock solution tank 1 is sent to the cleaning tank 3 via the pipe 2. Here, the organic suspended substance (SS) can be sufficiently separated into the liquid by thoroughly washing the organic suspended substance (SS) with well water or circulating water.
And, for example, organic suspension substances (SS) of 300 μm or more which are hard to be decomposed, such as potato skin, root, and trunk,
It is removed by the filtering member 3. The viscosity of the filtrate is 10
It is processed so as to be less than or equal to cP.

Next, the filtrate is sent to the solid-liquid separator 6 through the pipe 5. Here, the organic suspension material (SS) having a relatively large particle size with a sedimentation speed of 1 m / hour or more is
Transferred to the side a, and on the side of the supernatant 6b, only the organic suspended substance (SS) having a sedimentation speed of 1 m / hour or less and a relatively small particle size is formed. At this time, the concentration of the organic suspended substance (SS) in the concentrated liquid 6a is controlled to 50,000 mg / l or less.

As described above, the high-concentration organic wastewater containing the organic suspended solids (SS) contains the supernatant liquid 6b containing little organic suspended solids (SS) and the high-concentrated organic wastewater. It is separated into a concentrated liquid 6a containing a suspended substance (SS).

Then, the supernatant 6b and the concentrate 6a are separately processed. First, the treatment of the supernatant 6b will be described. The supernatant liquid 6b having a low concentration of organic suspended solids (SS) was used in a high efficiency anaerobic bioreactor 12 such as a fluidized bed reactor to obtain a BOD load of 5 kg-BOD / m.
It is processed with a high load of ³ / day or more.

Supernatant liquid 6b flowing out of the solid-liquid separation device 6
Is stored in the supernatant liquid storage tank 8 through the pipe 7, and the pipe 11
To the highly efficient anaerobic bioreactor 12 via. At this time, as the high-efficiency anaerobic bioreactor 12, three types of bioreactors are prepared depending on the CODcr concentration of the supernatant 6b when undiluted. That is, when the CODcr concentration of the undiluted supernatant 6b is 6,000 mg / l or less, UASB, and when 6,000 to 15,000 mg / l or less,
A fixed bed, and a fluidized bed when it is 15,000 mg / l or more.

In the high efficiency anaerobic bioreactor 12,
Since the supernatant 6b has a low concentration of organic suspended solids (SS), the decomposition rate of organic substances is dramatically improved, and only 9 is anaerobic.
A BOD removal rate of 0% or more is achieved, resulting in a large amount of methane gas. The generated methane gas is stored in the gas holder 17 via the pipe 16.

Next, the treatment of the concentrated liquid 6a will be described. Concentrated liquid containing high concentration of organic suspended solids (SS) 6
a is a membrane separation device 24 having an ultrafiltration membrane or a microfiltration membrane
It is processed in the floating bioreactor 10 in combination with.

The concentrated liquid 6a containing a high-concentration organic suspended substance (SS) is sent to the floating bioreactor 10 through a pipe 9 which communicates with the concentrated liquid 6a side of the solid-liquid separator 6. In the floating bioreactor 10, the BOD load is 1 to 5 kg-BOD while being agitated by the agitating action of the sludge circulating liquid and the agitating action of the air lift by the generated gas.
It is processed at a relatively high load of about / m ³ / day. Then, the sludge in the floating bioreactor 10 is extracted and controlled so that the sludge concentration becomes 30,000 mg / l or less. At the same time, by the circulating water tank 22, the floating bioreactor 1
The sludge in 0 is subjected to a membrane separation process by the membrane separation device 24.

As described above, since the supernatant liquid 6b and the concentrated liquid 6a are separately processed, the organic suspended substance (S
There are advantages such that the retention time of S) can be remarkably extended, oxygen and bacteria can be maintained at a high concentration, and the treated water quality is good and stable. As a result, the treatment can be performed with a relatively high load of BOD load of about 2 kg-BOD / m ³ / day, and the generation of excess sludge can be made extremely small. In addition, the generated sludge can be concentrated and
Since it can be dehydrated, energy and chemical costs for sludge treatment can be saved.

Next, the case where the present invention is applied to corn shochu waste liquid will be described. First, for the supernatant, C
Waste liquor from corn with an ODcr concentration of 18,000 mg / l,
When treated with a fluidized bioreactor, BO
A D load of 13.5 Kg-BOD / m ³ / day and a BOD removal rate of 85% or more were obtained. Further, 90% or more of CODcr could be recovered as methane.

Next, concerning the concentrated liquid, in the corn shochu waste liquid, 9% of 20,000 mg / l of the organic suspended substance (SS) was added.
0% or more was decomposable, and the CODcr removal rate was 90% or more. Further, 90% or more of the removed CODcr could be recovered as methane.

FIGS. 2 and 3 were prepared based on this experiment. FIG. 2 shows the sludge conversion rate in the methane fermentation treatment of the corn shochu waste liquor, and FIG. 3 shows the COD removal in the methane fermentation treatment of the corn shochu waste liquor. Indicates the rate.

[0041]

As described above, according to the method and apparatus for anaerobic treatment of high-concentration organic wastewater containing organic suspended matter according to the present invention, the high-concentration organic suspended matter (S
During the anaerobic treatment of high-concentration organic wastewater containing S),
Organic suspension substance (SS) by dilution water or treated water
Are thoroughly washed, and solid-liquid separation is performed, and an organic suspended substance (S
S) Separation into a supernatant liquid having a relatively low concentration and a concentrated liquid containing a high concentration of an organic suspended substance (SS), and the supernatant liquid is UAS.
B, a high-efficiency anaerobic bioreactor such as a solid bed or a fluidized bed is processed at a high speed, and a concentrated liquid is processed by a device combining a floating bioreactor and a membrane separation device. The decomposition rate of (SS) is dramatically improved, and a BOD removal rate of 90% or more is achieved only by anaerobic treatment, and as a result, a large amount of methane gas is obtained. The generated methane gas can be used as an energy source. The average load applied to the anaerobic bioreactor that processes the supernatant and the highly efficient floating doio reactor that processes the concentrate is a BOD load of 3.3 kg-BOD.
Since it is possible to achieve a high load of / m ³ / day or more, the installation area of the device can be reduced and construction costs can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of an anaerobic treatment apparatus for high-concentration organic wastewater containing an organic suspended substance according to the present invention.

FIG. 2 is a graph showing a sludge conversion rate in a methane fermentation process of corn shochu waste liquid.

FIG. 3 is a graph showing the COD removal rate in the methane fermentation treatment of corn shochu waste liquid.

[Explanation of symbols]

 1 stock solution tank 3 washing device 6 solid-liquid separation device 10 floating bioreactor 12 anaerobic bioreactor 23 circulating water tank 24 membrane separation device

Claims (7)

[Claims] 1. Washing wastewater containing an organic suspended substance in a high concentration, performing solid-liquid separation, and separating the solid-liquid separated supernatant liquid,
It is supplied to an anaerobic bioreactor and treated by methane fermentation, and the solid-liquid separated organic suspended substance is supplied to a floating type anaerobic bioreactor having a membrane separation device and treated by methane fermentation. An anaerobic treatment method for high-concentration organic wastewater containing organic suspended matter, which is characterized by the above. 2. The high-concentration organic wastewater containing organic suspended substances according to claim 1, wherein the wastewater containing high-concentration organic suspended substances is washed with treated water or diluted water. Anaerobic treatment method. 3. The organic wastewater according to claim 1, wherein the high-concentration organic wastewater containing organic suspended matter is shochu wastewater, brewer's yeast wash wastewater, sake rinsing wastewater, and starch wastewater. Anaerobic treatment method for highly concentrated organic wastewater containing suspended solids. 4. The organic suspended substance according to claim 1, which is characterized in that waste water containing a high concentration of the organic suspended substance is washed to remove the organic suspended substance of 300 μm or more. Anaerobic treatment method for high concentration organic wastewater containing. 5. A stock solution tank for storing waste water containing a high concentration of organic suspended solids, a washing device for washing waste water containing a high concentration of organic suspended solids, a solid-liquid separation device, and a solid-liquid separator. Anaerobic bioreakly, which takes in the supernatant of the liquid separator and treats it by methane fermentation, and wastewater containing a high concentration of concentrated organic suspended matter in the solid-liquid separator, which is treated by methane fermentation. Floating type anaerobic bio rear cree,
An anaerobic treatment device for high-concentration organic wastewater containing organic suspended matter, comprising: a membrane separation device connected to a floating type anaerobic bioreactor. 6. The cleaning device according to claim 5, wherein the cleaning device for cleaning the wastewater containing a high concentration of organic suspended solids is 300 μm.
An anaerobic treatment apparatus for high-concentration organic wastewater containing organic suspended matter, comprising a filter member for removing the organic suspended matter described above. 7. The organic suspension substance according to claim 5, wherein a circulation device is interposed between the floating type anaerobic bioreactor and the membrane separation device. Anaerobic treatment equipment for highly concentrated organic wastewater.