JPH0579399B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a bioreactor that uses microorganisms to produce valuables and purify pollutants, and particularly relates to a bioreactor that uses microorganisms to produce valuables and purify pollutants, and particularly relates to a bioreactor that uses microorganisms to produce valuables and purify pollutants, and particularly relates to a bioreactor that uses microorganisms to produce valuable substances and purify pollutants, and particularly relates to a bioreactor that uses microorganisms to produce valuable substances and purify pollutants. Regarding floor bioreactors.

[Conventional technology]

As a conventional fluidized bed type bioreactor, for example, the one shown in FIG. 3 is known. This bioreactor 1 ejects liquid or gas from the inverted conical bottom 3 of a cylindrical reaction container 2 to bring microbial carriers 4 floating from the vicinity of the bottom 3 to the middle of the container 2 into a fluid state. Carrier 4...
Microorganisms that adhere to, adhere to, or are contained in
The wastewater 5 in the reaction vessel 2 is subjected to biological treatment, and the treated wastewater 5 is configured to flow out from an overflow weir 6 at the upper part of the reaction vessel 2 through an overflow pipe 6'.

[Problem that the invention seeks to solve]

However, in such a bioreactor 1, the supernatant of the treated water flows out from the overflow weir 6 at the upper end of the reaction vessel 2, so it is necessary to separate the microbial carriers 4 from the treated water. .
This separation of the carriers 4 is usually carried out by gravity sedimentation separation from the viewpoint of cost. For this reason, the carrier 4 must necessarily be made of sand, diatomaceous earth, or the like, which is much heavier than water. However, if a heavy carrier 4 is used, since the specific gravity is large, a large amount of energy is required to fluidize the carrier, thereby limiting the amount of carrier. For this reason, carrier 4...
The filling amount is only 3 of the actual reaction volume of reaction vessel 2.
~20% of the reaction volume in the fluidized state
The upper limit is ~60%. Therefore, the amount of microorganisms retained on the carrier 4 is also limited, and for example, in methane fermentation using sugar wastewater as the target wastewater, the limit is 40,000 ppm.

In some cases, a separate sedimentation tank is installed to separate carriers, but in that case, a new sedimentation tank is required, and in order to separate in the sedimentation tank, carriers with microorganisms attached and heavier than water are required. , a large amount of energy is required to spread the fluid throughout the device.

On the other hand, in the case of a bioreactor, it is known that the reaction rate is proportional to the amount of microorganisms, and the larger the amount of microorganisms, the higher the reaction rate, the shorter the residence time, and the more compact the device can be.

Therefore, the conventional fluidized bed type bioreactor 1 has problems such as poor processing efficiency per unit volume of the reaction vessel 2, inability to perform highly efficient processing, and difficulty in downsizing the device. It was hot.

[Means for solving problems]

Therefore, in this invention, inside the reaction vessel main body,
An intermediate cylindrical body is formed to have a smaller diameter than the reaction vessel main body, an upper end protrudes above the level of the stored liquid, and a lower end is close to the bottom of the reaction vessel main body, and a wastewater receiving port for receiving the wastewater to be treated is provided inside the intermediate cylindrical body. At the same time, a waste water outlet for taking out treated wastewater is provided outside the middle cylinder, and a jetting means for dispersing gas is disposed at the bottom of the reaction vessel main body, and a waste water outlet is provided at the bottom of the main body of the reaction vessel. An inner cylindrical part is provided in the half part at a constant interval from the middle cylinder body and guides the gas diffused from the jetting means upward, and is spaced at a constant interval from the bottom of the reaction vessel main body. Approximately vertically above the inner cylindrical portion, a certain gap is opened between the inner cylindrical body and the inner cylindrical body at a position that approximately bisects the interior of the middle cylindrical body in the vertical direction. A cap-shaped partition wall is provided with its top facing upward to block the rise of the gas guided by the inner cylinder part and to guide the gas to the outside of the inner cylinder part. The space between the periphery and the periphery is a derivation area in which the heavy microbial carriers having a specific gravity higher than the liquid are allowed to settle downward and flow, and the space between the lower end periphery of the partition wall and the middle cylinder is guided to the outside of the inner cylindrical part. The above-mentioned problem is solved by guiding the gas upward to create a blow-up region in which lightweight microbial carriers having a specific gravity smaller than the liquid flow above the partition wall.

〔Example〕

FIG. 1 shows an example of a fluidized bed bioreactor of the present invention, and reference numeral 11 in the figure is a reaction vessel main body. This reaction vessel main body 11 includes a cylindrical outer cylinder part 11a and an inverted conical bottom part 11 connected to the outer cylinder part 11a.
It is composed of b. This reaction container body 11
Inside, a cylindrical intermediate cylinder part (middle cylinder body) 12 is provided coaxially with the outer cylinder part 11a, and this intermediate cylinder part (middle cylinder body) 12 has a predetermined space between it and the outer cylinder part 11a. spacing is maintained. Moreover, this intermediate cylinder portion 12
A cap-shaped partition wall 13 is provided approximately at the center of the inner side of the housing. This partition wall 13 is arranged so as to vertically divide the space inside the intermediate cylinder part 12 into two at approximately the center thereof, and is arranged so that the part corresponding to the upper part of the shade is located upward. The partition wall 13 is disposed at a predetermined distance between the partition wall 13 and the intermediate cylindrical portion 12 so that fluid can flow therebetween. Further, above the partition wall 13, a circular plate 14 in the shape of a cone is provided. The bottom portion of the circulation plate 14 has been removed and is missing, allowing liquid to flow therethrough. Further, the circulation plate 14 is also arranged at a predetermined distance from the intermediate cylinder portion 12. Further, vertically below the partition wall 13, that is, in the lower half of the intermediate cylindrical portion 12, an inner cylindrical portion 15 made of a cylindrical body with a slightly smaller diameter is provided at a constant distance from the intermediate cylindrical portion 12. The lower end of this inner cylindrical part 15 extends to a position further below the lower end of the intermediate cylindrical part 12 and at a constant distance from the bottom 11b of the reaction vessel main body 11, and has a wide diameter. has been done. A diffuser member 16 is provided below this inner cylindrical portion 15 . A diffuser pipe (spouting means) 19 is connected to the diffuser member 16, which extends from the blower 17 through the valve 18, passing through the center of the bottom 11b of the reaction vessel main body 11.

Further, the upper end of the reaction vessel main body 11 has a main body 1
1 is provided with a lid portion 20 that airtightly covers the device. A generated gas discharge pipe 21 and a circulating gas pipe 22 are connected to the lid part 20, and the upper end of the intermediate cylinder part 12 is connected in an airtight manner. Also,
A part of the lid part 20 constitutes an overflow weir (wastewater discharge port) 23 , and a drain pipe 25 is connected to the overflow weir 23 via a valve 24 . Furthermore, an inflow pipe (wastewater receiving port) 26 is attached to the lid 20 to introduce the water to be treated into the intermediate cylinder 12 through the lid 20 . In addition, the generated gas exhaust pipe 2
1 is connected to a gas storage tank 28 via a valve 27, and the circulating gas pipe 22 is connected to the blower 17 via a valve 29 and to the aeration pipe 19 via a valve 30.

Next, a method of operating such a bioreactor will be explained using sugar waste liquid as an example.

In the reaction vessel main body 11, the sugar waste liquid is first introduced into the inflow pipe 2.
Supplied from 6. At this time, since the inflow pipe 26 opens into the interior of the intermediate cylindrical portion 12, the sugar waste liquid is supplied into the intermediate cylindrical portion 12. Reaction container body 11
The interior is filled with heavy microbial carriers and lightweight microbial carriers. The heavy microbial carriers are placed below the partition wall 13 in the intermediate cylinder 12, and the lightweight microbial carriers are also placed above. The weight microbial carrier and the lightweight microbial carrier are set at a volume ratio of 3:2, and an amount equivalent to 40% of the actual reaction volume of the reaction vessel body 11 is filled. As lightweight microbial carriers, plastic particles with a specific gravity lower than that of water, natural mineral particles such as pumice with air bubbles or pores inside, foamed plastic particles, and other particles lighter than water in natural or artificial usage conditions can be used. A material containing fixed, attached, or encapsulated microorganisms depending on the type of biological treatment is used, and a particle size of about 0.1 to 10 mm and a specific gravity of about 0.90 to 0.97 in the used state are suitable. Examples of gravimetric microbial carriers include particles with a specific gravity greater than water, such as sand, activated carbon, diatomaceous earth, phosphate rock, coke, zeolite, plastic particles, foamed plastic particles, and natural mineral particles having air bubbles and pores inside. is used to similarly fix microorganisms to particles with a particle size of about 0.1 to 1 mm.
Those that are attached or included are used, and those that have a specific gravity of about 1.05 to 1.20 in the used state are preferably used. It is desirable to use particles with a smaller diameter for a heavy microorganism carrier with a higher specific gravity, and to use particles with a smaller diameter for a lightweight microorganism carrier with a lower specific gravity.

Then, the blower 17 is operated to remove the air diffuser 16.
The gas is further diffused to fluidize and circulate each carrier within the container body 11. In this way, the sugar in the sugar waste liquid is subjected to acid fermentation and methane fermentation by the action of the microorganisms held on each carrier, producing methane gas (CH ₄ ) and carbon dioxide (CO ₂ ), and at the same time, the sugar waste liquid is purified.

Here, the heavy microorganism carriers located below the inner cylinder part 15 rise within the inner cylinder part 15 due to the aeration, and the rising is blocked by the partition wall 13, flows outward along the partition wall 13, and rises. The inner cylinder part 1 loses its energy.
5 and the lower end periphery of the partition wall 13, the air sinks downward and returns to the bottom 11b, where it is diffused again and circulated in the same way. (See the solid line arrow in Figure 1). On the other hand, the diffused gas flows outward from the bottom surface of the partition wall 13 , rises to the upper side of the partition wall 13 from the blow-up area between the lower edge of the partition wall 13 and the intermediate cylinder part 12 , and circulates along the inside of the intermediate cylinder part 12 . It rises on the outside of the plate 14 and escapes from the water surface (see the broken line arrow in Figure 1). Accompanied by this gas flow, the lightweight microbial carrier rises on the outside of the circulation plate 14, then flows down on the inside of the circulation plate 14, and circulates around the circulation plate 14.

A part of the methane gas and carbon dioxide generated by the biological reaction is extracted from the generated gas discharge pipe 21 and stored in the gas storage tank 28, and the remaining part is sent to the blower via the circulating gas pipe 22 to be used as a diffuser gas. used in circulation as

Further, the purified treated sugar waste liquid is transferred to the intermediate cylindrical portion 12.
and the outer cylinder part 11a, flows out from the overflow weir 23, passes through the drain pipe 25, and is sent to the next higher treatment step.

According to such a fluidized bed bioreactor,
The reaction area is vertically divided into two parts by the partition wall 13, and the lightweight microbial carriers are placed above and the heavy microbial carriers are placed below, respectively, and are made to flow by gas aeration, so that the overall amount of microbial carriers can be reduced. The amount of microorganisms can be increased to about 40 to 50% of the actual reaction volume, and the amount of microorganisms can be increased to 60,000 to 80,000 ppm, for example, as in the case of methane fermentation of sugar waste liquid in this example. Therefore, processing efficiency is greatly increased and the device can be made smaller. Furthermore, the energy for fluidizing the microbial carrier may be the same as the energy for fluidizing the conventional heavy microbial carrier, resulting in improved energy efficiency. Furthermore, even though lightweight microbial carriers are used and fluidized in the upper region of the reaction vessel main body 11, the presence of the intermediate cylinder portion 12 and the partition wall 13 prevents any outflow of the lightweight microbial carriers. Further, a heavy microorganism carrier is also provided inside the intermediate cylinder part 12, and the air diffuser 16
Since an upward flow is generated in the center of the intermediate cylinder part 12, the heavy microbial carriers will not leak out of the intermediate cylinder part 12, and furthermore, the treated wastewater can be taken out outside the intermediate cylinder part 12. , here complete separation of microbial carriers is possible. Moreover, the partition wall 13 keeps both the lightweight microbial carrier and the heavy microbial carrier almost completely separated at all times, so that the intended function is always exhibited.

FIG. 2 shows another example of the bioreactor of the present invention, and the same components as in the example shown in FIG. 1 are given the same reference numerals and their explanations will be omitted. The fluidized bed bioreactor of this example uses a treatment liquid to fluidize microbial carriers. A liquid suction pipe 31 for sucking the processing liquid is opened above the partition wall 13 , and this liquid suction pipe 31 penetrates through the lid 20 and is connected to a liquid pump 33 via a valve 32 . A part of the processing liquid pumped by the liquid pump 33 passes through the blow-off pipe 34 and the valve 35 and reaches the bottom 1 of the main body 11.
1b is blown out from the outlet (spouting means) 36, and the remainder is sent to a water sprinkling member 39 provided above the water surface via a valve 37 and a water sprinkling pipe 38.
Water is sprinkled. The lightweight microbial carrier is mainly fluidized by water sprinkling from this water sprinkling member 39, and is
It circulates in the area above 3. For lightweight microbial carriers, lighter ones are preferred.

〔Effect of the invention〕

As explained above, the fluidized bed bioreactor of the present invention includes a middle cylinder provided inside the reaction vessel main body, the inside of this middle cylinder divided vertically into two by a partition wall,
Light microbial carriers are arranged in the upper region of this partition wall, and heavy microbial carriers are arranged in the lower region for fluidization, so the amount of microbial carriers can be reduced to the actual reaction vessel volume with the same fluidization energy as before. of 40
50%, the amount of microorganisms retained can be increased to about 1.5 to 2 times the conventional amount, and the volumetric efficiency of the reaction can be improved by about 30 to 50%. In addition, due to the action of the inner cylinder and the ejection means, both the lightweight microbial carrier and the heavy microbial carrier are constantly flowing within the inner cylinder, so there is no leakage of the microbial carrier, and complete separation of the microbial carrier and the treated water is possible. It is. Furthermore, since the partition wall almost completely separates the lightweight microbial carriers from the heavy microbial carriers, it is possible to always exhibit the desired high functionality even though it is a completely fluid type.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are both schematic configuration diagrams showing an example of a fluidized bed type bioreactor of the present invention, and FIG. 3 is a schematic configuration diagram showing an example of a conventional fluidized bed type bioreactor. 11...Reaction container main body, 11a...Outer cylinder part, 1
1b...bottom, 12...middle cylinder part (middle cylinder), 1
3... Partition wall, 16... Air diffusion member (spouting means),
17...Blower, 19...Diffuser pipe, 20...Lid, 22...Circulating gas pipe, 31...Liquid suction pipe, 33
. . . Liquid feed pump, 34 . . . Blowout pipe, 36 .

Claims (1)

[Claims] 1. A middle cylindrical body is provided inside the reaction vessel body, the diameter of which is smaller than that of the reaction vessel body, the upper end of which protrudes above the level of the stored liquid, and the lower end of which is close to the bottom of the reaction vessel body;
A wastewater inlet for receiving the wastewater to be treated is provided inside the middle cylinder, while a wastewater outlet for taking out the treated wastewater is provided outside the middle cylinder, and gas is diffused at the bottom of the reaction vessel main body. A blowout means is disposed in the lower half of the central part of the middle cylinder, and an inner cylinder part is spaced apart from the middle cylinder by a certain distance and guides the gas diffused from the blowout means upward. The inner cylinder is provided at a constant interval from the bottom of the reaction vessel main body, and is located approximately vertically above the inner cylinder at a position that vertically divides the inside of the inner cylinder into approximately two parts. A cap-shaped partition wall is opened with a certain gap from the cylinder body to block the rise of the gas guided upward by the inner cylinder part and to guide the gas to the outside of the inner cylinder part, with its top facing upward. The area between the upper end periphery of the inner cylinder part and the lower end periphery of the partition wall is used as a derivation area in which heavy microorganism carriers having a specific gravity greater than the liquid are allowed to settle and flow downward, and the lower end periphery of the partition wall and the middle cylinder A flow characterized in that the gas guided to the outside of the inner cylindrical part between the body and the body is guided upward to create a blow-up area in which lightweight microbial carriers having a specific gravity smaller than the liquid flow above the partition wall. Floor bioreactor.