WO2014199972A1

WO2014199972A1 - Alcohol production waste water treatment device, and treatment method

Info

Publication number: WO2014199972A1
Application number: PCT/JP2014/065308
Authority: WO
Inventors: 和也小松; 田中　倫明; 智弘清川
Original assignee: 栗田工業株式会社
Priority date: 2013-06-10
Filing date: 2014-06-10
Publication date: 2014-12-18
Also published as: JP2014237102A; MY169243A; JP5846160B2

Abstract

An anaerobic treatment of distilled condensed water from alcohol production waste water, wherein the consumption of an alkali agent is suppressed, and a high-load, stable treatment is performed. A method in which, when performing the anaerobic treatment on condensed water obtained by performing a distillation treatment on organic waste water discharged from an alcohol production waste water production step, while a portion of the treated water is circulated as circulating water, the condensed water is treated in an upflow fluidised bed anaerobic reactor in which anaerobic microorganisms adhered to the surface of a carrier perform the treatment. A circulation ratio, which is calculated as the ratio of the amount of circulating water to the amount of condensed water treated in the anaerobic reactor (circulating water amount/condensed water amount), is preferably 5 or more.

Description

Alcohol production wastewater treatment device and treatment method

The present invention relates to a treatment apparatus and a treatment method for wastewater generated when alcohol such as bioethanol and distilled liquor is produced using sugarcane, corn, wheat and the like as raw materials. The present invention particularly relates to an apparatus and method for anaerobically treating condensed water obtained by distillation treatment of alcohol production wastewater.

In the method of producing bioethanol and distilled liquor, raw materials for grains such as sugar cane, corn, and wheat are subjected to pretreatment and saccharification treatment such as acid treatment, alkali treatment, biological treatment, and physical treatment to produce a carbon source. The By fermenting the obtained carbon source with yeast, a low-concentration ethanol-containing fermentation broth is produced. Bioethanol and distilled liquor are produced by concentrating and distilling the fermented liquor and further purifying as necessary (for example, Patent Document 1).

In the process for producing alcohol, wastewater containing COD containing a very high concentration of 100,000 mg / L or more is discharged in the fermentation liquid distillation step. This alcohol production wastewater is mainly composed of organic acids produced in the fermentation process, in addition to grain residues, waste yeast, and sugars. Alcohol production wastewater is conventionally treated by the following method.
(1) In a factory having vast land, treated water is obtained by directly treating alcohol production wastewater with an anaerobic lagoon. The residual sludge of the anaerobic lagoon is effectively used for fertilizers and the like because components such as nitrogen, phosphorus, and potassium in the fermentation liquid are concentrated.
(2) In a factory that has a biomass boiler and can secure a large amount of steam, the alcohol production wastewater is further distilled. Recycle distillate bottoms (concentrated residue) as liquid fertilizer. The condensed water of the tower top distillate gas whose COD concentration is reduced to about several thousand mg / L by distillation is treated with an anaerobic lagoon.

Conventionally, UASB (Upflow Anaerobic Sludge Blanket: Upflow high-speed treatment using granular sludge with high density and high sedimentation as a treatment method for high-concentration organic wastewater discharged from beer, beverages, food factories, etc. The counter-current anaerobic sludge blanket method is known. In the UASB method, organic wastewater is introduced into a reaction tank that holds a sludge blanket formed of granular sludge, and is allowed to contact the sludge blanket by flowing upward. An EGSB method (Expanded Granule) that allows organic wastewater to flow through the reaction vessel with a higher height at a higher flow rate and expands the sludge blanket at a higher deployment rate than the UASB method. Sludge Blanket) is also known.

In the UASB method and the EGSB method, granular sludge in which anaerobic microorganisms are granulated is used, and the sludge containing anaerobic microorganisms is maintained and grown in the form of granules (grains). The biological treatment method using granular sludge can be operated at a high load because a high sludge retention concentration can be obtained as compared with a fixed bed or fluidized bed in which microorganisms are held on a carrier. In the UASB method and the EGSB method using granular sludge, it is necessary to stably form and maintain granular sludge in order to treat organic wastewater stably and satisfactorily. If granule sludge cannot be formed and maintained in the reaction tank, the treatment performance gradually decreases and may eventually become untreatable. For this reason, the examination for forming and maintaining the granular sludge in a reaction tank stably is made (for example, patent documents 2).

International Publication WO00 / 53791 JP 2008-279383 A

Among the conventional methods for treating wastewater from alcohol production, in the method of treating directly with an anaerobic lagoon, odors and greenhouse gases such as methane are discharged into the environment. A vast space of more than 100 days of HRT is required.

In the method of treating the condensed water obtained by distilling alcohol production wastewater with an anaerobic lagoon, fertilizer components such as nitrogen, phosphorus, and potassium in the alcohol production wastewater are concentrated (about 1/3 to 1/4 as the amount of water). Can be recovered and effectively used as fertilizer. Since the COD concentration of the condensed water supplied to the anaerobic lagoon is significantly reduced as compared with the alcohol production waste water before distillation, the organic load of waste water treatment is reduced. Compared to the direct anaerobic lagoon treatment of the alcohol production wastewater as it is, the treatment facility can be downsized and treated water with good water quality can be obtained. However, since an anaerobic lagoon is used, odors and other exhaust gases are generated.

When trying to process distilled condensate from alcohol production wastewater with a high load, such as the UASB method or EGSB method, this condensate is mainly composed of organic acids and does not contain sugars required to form granules. Therefore, it is impossible to stably form and maintain granules. A large amount of alkaline agent is required to neutralize the organic acid.

The present invention provides an apparatus and a method for treating alcohol production wastewater that can suppress the consumption of an alkaline agent and perform high load and stable treatment in anaerobic treatment of distilled condensed water of alcohol production wastewater. This is the issue.

The present inventor is an anaerobic reaction of an upward flow type fluidized bed type in which anaerobic microorganisms attached to the surface of a carrier are treated while anaerobic treatment of distilled condensed water of alcohol production wastewater is circulated. It has been found that by applying the tank, it is not necessary to form granules and a good treatment can be performed. The present inventor can use the alkalinity of the treated water to neutralize the organic acid in the raw water by increasing the circulation amount of the treated water with respect to the raw water (condensed water). Found that can be reduced.
The circulation of the treated water is also performed by the UASB method and the EGSB method using granules. However, if the circulation rate is increased, the upward flow rate (LV) in the anaerobic reaction tank increases and the granules are more likely to flow out. The circulation rate can only be increased to about 4 m / hr. In the treatment using the carrier, the sedimentation rate of the carrier is 200 to 500 m / hr, which is significantly higher than the granule sedimentation rate of 50 to 80 m / hr. Therefore, even if the circulation rate is increased to about LV 4 to 20 m / hr, The microorganisms can be retained and processed stably.

The present invention has been achieved on the basis of such findings, and the gist thereof is as follows.

[1] In an alcohol production wastewater treatment apparatus for anaerobically treating condensed water obtained by distillation treatment of organic wastewater discharged from the production process of alcohol production wastewater, while circulating a part of the treated water as circulating water An apparatus for treating wastewater from alcohol production comprising an upward flow fluidized bed type anaerobic reaction tank for treating with anaerobic microorganisms adhering to the surface of the carrier, wherein the condensed water is COD _Cr 500-20,000 mg / L The organic acid-containing water containing 30 to 90% of the organic acid component in the total COD _Cr , and is calculated by the ratio of the circulating water amount to the condensed water amount treated in the anaerobic reaction tank (circulating water amount / condensed water amount). A treatment apparatus for alcohol production waste water, wherein the circulation ratio is 5 or more.

[2] An apparatus for treating wastewater from alcohol production according to [1], wherein an upward flow velocity (LV) of the anaerobic reaction tank is 4 to 20 m / hr.

[3] In [1] or [2], the carrier has a specific gravity of 1.1 to 1.3 and an average particle diameter of 1 to 30 mm, and the carrier filling rate of the upward flow fluidized bed anaerobic reaction tank is as follows. Alcohol production waste water treatment equipment characterized by 10 to 80%.

[4] In any one of [1] to [3], the anaerobic treatment conditions in the upward flow type fluidized bed type anaerobic reaction tank are as follows: temperature 20 to 60 ° C., pH 6 to 8, tank load 2 to 40 kg-COD _An apparatus for treating alcohol production wastewater, wherein _Cr / m ³ / day.

[5] In any one of [1] to [4], the circulating water includes bicarbonate generated by decomposing an organic acid in the condensed water, and the condensed water is added with alkali. An apparatus for treating wastewater from alcohol production, wherein the pH is adjusted using the alkalinity of the circulating water.

[6] In a method for treating alcohol production wastewater in which condensed water obtained by distillation treatment of organic wastewater discharged from the production process of alcohol production wastewater is anaerobically treated, a portion of the treated water is circulated through the condensed water. An alcohol production wastewater treatment method for introducing an anaerobic treatment into an upward flow fluidized bed type anaerobic reaction tank that performs treatment with anaerobic microorganisms attached to the surface of the carrier while circulating as water, wherein the condensed water is COD _Cr 500 to 20,000 mg / L, organic acid-containing water containing 30 to 90% of organic acid components in the total COD _Cr , and the ratio of the circulating water amount to the condensed water amount treated in the anaerobic reaction tank ( A method of treating alcohol production wastewater, characterized in that the circulation ratio calculated by (circulated water amount / condensed water amount) is 5 or more.

[7] A method for treating wastewater from alcohol production according to [6], wherein an upward flow velocity (LV) of the anaerobic reaction tank is 4 to 20 m / hr.

[8] In [6] or [7], the carrier has a specific gravity of 1.1 to 1.3 and an average particle diameter of 1 to 30 mm, and the carrier filling rate of the upward flow fluidized bed anaerobic reaction tank is as follows. A method for treating wastewater from alcohol production, characterized by comprising 10 to 80%.

[9] In any one of [6] to [8], the anaerobic treatment conditions in the upward flow type fluidized bed type anaerobic reaction tank are a temperature of 20 to 60 ° C., a pH of 6 to 8, and a tank load of 2 to 40 kg-COD. _{It is Cr} / m _< ³ > / day, The processing method of the alcohol manufacture waste_water | drain characterized by the above-mentioned.

[10] In any one of [6] to [9], the circulating water includes bicarbonate generated by decomposing an organic acid in the condensed water, and an alkali is added to the condensed water, A method for treating wastewater from alcohol production, wherein the pH is adjusted using the alkalinity of circulating water.

According to the present invention, in anaerobic treatment of distilled condensed water of alcohol production wastewater, while reducing the consumption of alkaline agent, it is possible to efficiently obtain high quality treated water by performing high load and stable treatment. it can. If it is an upward flow type fluidized bed type anaerobic reaction tank, the problem of an odor and exhaust gas is also reduced, without requiring a vast space like the conventional anaerobic lagoon.

It is a systematic diagram which shows an example of embodiment of the processing apparatus of the alcohol manufacture waste_water | drain of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the present invention, the condensed water obtained by distillation treatment of the organic wastewater discharged from the production process of alcohol production wastewater is anaerobically treated. In the alcohol production process, a carbon source obtained by saccharifying grains and the like is fermented by yeast to produce a fermentation liquid containing alcohol. The fermented liquor is concentrated, distilled, and further purified as necessary to produce alcohol. When the high-concentration COD-containing wastewater discharged as the bottoms of the distillation tower in the fermentation liquid distillation step is distilled, the condensed water and the bottoms of the distillation tower, which are concentrated residues, are separated. This condensed water is treated by the method and apparatus of the present invention. This condensed water is preferably obtained by condensing the overhead effluent gas of a distillation column for distilling wastewater containing high concentration COD.

This condensed water is mainly composed of organic acids such as acetic acid and propionic acid. This condensed water is an acidic wastewater containing about 30 to 90% of organic acid components in the total COD _Cr , having a COD _Cr concentration of about 500 to 20,000 mg / L, and a pH of about 3 to 5.

In the present invention, such condensed water is anaerobically treated in an upward flow fluidized bed type anaerobic reaction tank.

FIG. 1 is a system diagram showing an embodiment of a treatment apparatus for alcohol production wastewater of the present invention having an upward flow type fluidized bed anaerobic reaction tank according to the present invention.
In FIG. 1, 1 is a pH adjustment tank, 2 is an upward flow type fluidized bed type anaerobic reaction tank, and 3 is a treated water tank.
Raw water (condensed water) is introduced into the pH adjusting tank 1 from the pipe 11, and part of the treated water is introduced as circulating water from the treated water tank 3 through the pipe 12. An alkaline agent is added to the pH adjusting tank 1 through a pipe 13 to adjust the pH.

The water whose pH has been adjusted in the pH adjusting tank 1 is introduced from the pipe 14 to the bottom of the upward flow type fluidized bed type anaerobic reaction tank 2. The anaerobic reaction tank 2 is filled with a carrier 4, and the water introduced into the anaerobic reaction tank 2 flows the carrier 4 in the tank in the process of flowing upward in the tank, It is treated with anaerobic microorganisms attached to the carrier 4. The treated water is introduced into the treated water tank 3 through the pipe 15.

The treated water tank 3 is provided with a submersible pump 5 and a return pipe 16 for returning the carrier flowing out from the anaerobic reaction tank 2 to the anaerobic reaction tank 2. The effluent carrier is returned to the anaerobic reaction tank 2 through the pipe 16. A carrier outflow prevention screen 6 is provided in the vicinity of the treated water outlet in the treated water tank 3. The treated water that has passed through the screen 6 is taken out from the pipe 17, part of it is circulated through the pipe 12 as circulating water to the pH adjustment tank 1, and the rest is discharged out of the system. The blower 7 performs aeration cleaning of the screen in order to prevent the screen 6 from being blocked. The gas of the blower 7 is preferably air or nitrogen gas.

FIG. 1 shows an example of the apparatus for treating alcohol production wastewater of the present invention, and the apparatus for treating alcohol production wastewater of the present invention is not limited to the illustrated one.

For example, the pH adjustment tank is not necessarily required, and the circulating water may be injected into the line by connecting the circulating water circulation pipe to the pipe for introducing the raw water into the bottom of the anaerobic reaction tank. Conversely, raw water may be injected into a circulation pipe that circulates part of the treated water to the bottom of the anaerobic reaction tank. In this case, the alkaline agent for pH adjustment can be line-injected into these pipes.

The treated water tank is not necessarily required, and this can be omitted, and a part of the treated water can be circulated to the anaerobic reaction tank through the circulating water circulation pipe branched from the treated water extraction pipe. In this case, the screen for preventing the carrier from flowing out is provided in the vicinity of the treated water outlet in the anaerobic reaction tank. As the blower gas for the blower for preventing the blockage of the screen, a gas not containing oxygen such as nitrogen gas is used in order to maintain the anaerobic state in the anaerobic reaction tank.

Furthermore, a neutralization tank and an acid generation tank can be provided upstream of the anaerobic reaction tank.

There are no particular restrictions on the material, shape, size, etc. of the carrier filled in the upward flow fluidized bed type anaerobic reaction tank, but a resin such as polyolefin or polypropylene is preferred, and the specific gravity is about 1.1 to 1.3. Those having a specific gravity slightly higher than that of water are preferred. The size of the carrier is preferably about 1 to 30 mm, particularly about 3 to 10 mm in terms of average particle diameter. The particle diameter is the diameter when the carrier is spherical, and corresponds to the length of one side if it is a cube, but in the case of other irregular shapes, the carrier is sandwiched between two parallel plates. The length of the part where the distance between the plates is the largest. Various shapes such as a spherical shape, a cubic shape, a rectangular parallelepiped shape, a rod shape, a cylindrical shape, and a disk shape can be used as the shape of the carrier.

The carrier filling rate of the upward flow type fluidized bed type anaerobic reaction tank (the ratio of the total volume (apparent volume) of the filled carrier to the effective volume of the anaerobic reaction tank) is about 10 to 80%, especially about 40 to 60%. It is preferable that

In the anaerobic treatment in the upward flow type fluidized bed type anaerobic reaction tank, the circulation ratio calculated by the ratio of the circulating water amount to the raw water (condensed water) amount (circulating water amount / raw water amount) is 5 or more, preferably 10 or more. Circulate part of the treated water. Thereby, the effect of utilizing the alkalinity of the treated water for neutralizing the raw water can be effectively exhibited, and the amount of the alkaline agent necessary for adjusting the pH of the raw water can be significantly reduced. That is, the condensed water, which is the raw water, is usually acidic at a pH of about 3 to 5, but the anaerobic treated water contains bicarbonate (alkalinity) produced by the decomposition and removal of the organic acid. It can be used for pH adjustment of raw water. However, if the circulation ratio is excessively increased, the processing efficiency is lowered and a large-capacity circulation pump is required. Therefore, the circulation ratio is preferably 20 or less.

Other anaerobic treatment conditions are not particularly limited, but it is preferable in terms of treatment efficiency to adopt the following conditions.
Temperature: 20-60 ° C, preferably 25-38 ° C or 50-55 ° C
pH: 6-8
Tank load: 2 to 40 kg-COD _Cr / m ³ / day
Upward flow velocity (LV): 4-20m / hr

Hereinafter, the present invention will be described more specifically with reference to examples.

[Example 1]
The raw water is condensed water having the following water quality obtained by distillation treatment of bioethanol production wastewater. Raw water was anaerobically treated under the following conditions using a treatment apparatus shown in FIG. 1 using a tank capacity of 4 L (a cylindrical shape having a diameter of 10 cm and a height of 50 cm) and an upward flow type fluidized bed type anaerobic reaction tank.

<Raw water quality>
pH: 4-5
COD _Cr : 5000 to 6000 mg / L
(The proportion of organic acids such as acetic acid and propionic acid in COD _Cr is 60-80%)

<Anaerobic treatment conditions>
Raw water treatment amount: 16L / day
Temperature: 35 ° C
Carrier: Polypropylene cylindrical carrier with bacterial cells attached Carrier size: Diameter 3 mm x Length 5 mm
Carrier filling amount: 1.6L
Carrier filling rate: 40%
Tank load of anaerobic reaction tank: 20kg-COD _Cr / m ³ / day

In the pH adjustment tank, 2N NaOH was added to adjust the pH to 6.5.

Change the circulation ratio of the treated water to 0 (no circulation), 1 (circulation in the same amount as the raw water), 4, 8, 10, 15, 20 in a range of LV 0.7-14 m / hr. When the treatment was performed, the COD _Cr of the treated water was 1,000 mg / L or less under any condition, and a removal rate of 80% or more was obtained.
Table 1 shows the NaOH consumption in the pH adjusting tank at each circulation ratio.

From Table 1, it can be seen that the higher the circulation ratio, the smaller the NaOH consumption, and a circulation ratio of 10 or more can be reduced to 20% or less of the NaOH consumption when the treated water is not circulated.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2013-121861 filed on June 10, 2013, which is incorporated by reference in its entirety.

Claims

In an alcohol production wastewater treatment device that anaerobically treats condensed water obtained by distillation treatment of organic wastewater discharged from the production process of alcohol production wastewater, while circulating a part of the treated water as circulating water, An apparatus for treating wastewater from alcohol production comprising an upward flow fluidized bed type anaerobic reaction tank that performs treatment with anaerobic microorganisms attached to the surface,
The condensed water is an organic acid-containing water containing COD Cr of 500 to 20,000 mg / L and containing 30 to 90% of an organic acid component in the total COD Cr .
An apparatus for treating alcohol production wastewater, wherein a circulation ratio calculated by a ratio of the amount of circulating water to the amount of condensed water to be treated in the anaerobic reaction tank (circulating water amount / condensed water amount) is 5 or more.
The apparatus for treating wastewater from alcohol production according to claim 1, wherein an upward flow velocity (LV) of the anaerobic reaction tank is 4 to 20 m / hr.
3. The carrier according to claim 1, wherein the carrier has a specific gravity of 1.1 to 1.3 and an average particle size of 1 to 30 mm, and the carrier filling rate of the upward flow type fluidized bed anaerobic reaction tank is 10 to 80%. An apparatus for treating wastewater from alcohol production, characterized in that:
The anaerobic treatment conditions in the upward flow fluidized bed type anaerobic reaction tank according to any one of claims 1 to 3 are a temperature of 20 to 60 ° C, a pH of 6 to 8, and a tank load of 2 to 40 kg-COD Cr / m. 3 / day is an apparatus for treating wastewater from alcohol production.
5. The circulating water according to claim 1, wherein the circulating water includes bicarbonate generated by decomposing an organic acid in the condensed water, and the condensed water is added with alkali and the circulating water. An apparatus for treating wastewater from alcohol production, wherein the pH is adjusted using the alkalinity of water.
In an alcohol production wastewater treatment method for anaerobically treating condensed water obtained by distillation treatment of organic wastewater discharged from the production process of alcohol production wastewater, the condensed water is circulated using a part of the treated water as circulating water. A method for treating alcohol production wastewater that is introduced into an upward flow fluidized bed type anaerobic reaction tank that is treated with anaerobic microorganisms attached to the surface of the carrier and anaerobically treated,
The condensed water is an organic acid-containing water containing COD Cr of 500 to 20,000 mg / L and containing 30 to 90% of an organic acid component in the total COD Cr .
A method for treating alcohol production wastewater, wherein a circulation ratio calculated by a ratio of the amount of circulating water to the amount of condensed water treated in the anaerobic reaction tank (circulating water amount / condensed water amount) is 5 or more.
7. The method for treating wastewater from alcohol production according to claim 6, wherein an upward flow velocity (LV) of the anaerobic reaction tank is 4 to 20 m / hr.
8. The carrier according to claim 6, wherein the carrier has a specific gravity of 1.1 to 1.3 and an average particle size of 1 to 30 mm, and the carrier filling rate of the upward flow fluidized bed anaerobic reaction tank is 10 to 80%. A method for treating wastewater from alcohol production.
9. The anaerobic treatment conditions in the upward flow type fluidized bed type anaerobic reaction tank according to any one of claims 6 to 8 are a temperature of 20 to 60 ° C., a pH of 6 to 8, and a tank load of 2 to 40 kg-COD Cr / m. 3 / day, a method for treating wastewater from alcohol production.
10. The circulating water according to claim 6, wherein the circulating water includes bicarbonate generated by decomposing an organic acid in the condensed water, and an alkali is added to the condensed water, and the circulating water is added. A method for treating wastewater from alcohol production, wherein the pH is adjusted using alkalinity.