JPS62247897A - Microorganism reaction vessel provided with thickening mechanism and microorganism reaction method - Google Patents

Abstract

PURPOSE:To reduce the size over the entire device by attaching a centrifugal thickening device to the inside of a reaction vessel in which microorganism reaction is effected and subjecting a liquid mixture contg. microorganisms in the vessel to a solid-liquid sepn. CONSTITUTION:The centrifugal thickening device 2 is attached to the inside of the reaction vessel 1 in which the microorganism reaction is effected. The liquid mixture 3 contg. the microorganism in the vessel is admitted into a rotor 4 of the centrifugal thickening device 2 and the rotor is rotationally driven to generate centrifugal force, by which the liquid mixture is subjected to the solid-liquid sepn. The liquid mixture thickened by the solid-liquid sepn. is returned in the slit 5 provided to the outside peripheral part of the rotor 4 into the vessel from the rotor inside. The separated liquid from the liquid mixture by the solid-liquid sepn. is discharged to the outside of the vessel from the rotor inside in a discharge pipe. As a result, the need for providing the installation for the solid-liquid sepn. to a point separate from the reaction vessel is eliminated, and the entire device is made compact. The floor area for installation and the required volume are thus reduced.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to reaction tanks used for carrying out microbial reactions, such as aeration tanks for wastewater treatment, other fermentation tanks, and culture tanks;
In particular, it relates to a reaction tank equipped with a concentration mechanism and a microbial reaction method in this reaction tank.

[Background technology] In reaction tanks that carry out microbial reactions such as fermenters, culture tanks, and activated sludge aeration tanks for wastewater, the stam of microorganisms or activated sludge that controls the reaction with the culture solution and wastewater that can serve as nutrients for microorganisms is used. The reaction proceeds by mixing flocs containing such microorganisms and maintaining environmental conditions suitable for the growth and reaction of these microorganisms. These environmental conditions include stirring the mixed liquid containing microorganisms to improve contact between the liquid and the microorganisms, and in the case of an aerobic microbial reaction, ensuring sufficient contact between the mixed liquid and the acidity or pure oxygen in the air to increase the In the case of anaerobic microbial reactions, it is often important to maintain a low redox potential by expelling dissolved oxygen in the mixed liquid or by bringing it into contact with a reducing gas. Furthermore, the smaller the amount of nutrients supplied per microorganism cell, the longer the microbial reaction will be completed.

Microbial reactions are generally carried out according to the flow shown in Figure 6. When treating wastewater such as sewage or industrial wastewater by microbial reaction, the process is basically the same as that shown in Figure 6, but the flow is specifically as shown in Figure 7. In Figures 6 and 7, solid line arrows indicate main flows, and dashed line arrows indicate incidental flows.
As shown by the solid arrows in the figure, in both cases, after the microbial reaction in the reaction tank and the microbial reaction in the activated sludge aeration tank,
A process of solid-liquid separation of a mixed liquid containing microorganisms into liquid and proliferating microorganisms is essential. In addition, as shown by the broken line arrow, when carrying out a productive microbial reaction in a reaction tank to increase the number of microbial cells, such as fermentation or cultivation, it is necessary to cultivate Stam as a seed and supply it in large quantities. It is also possible to separate the mixed liquid in the reaction tank into solid-liquid and return some of the proliferating microorganisms to the seed culture tank or reaction tank.In addition, in the case of wastewater treatment, the solid-liquid separated sludge is used as returned sludge and activated sludge. It may also be sent back to the aeration tank (reaeration may be performed during the process).

Here, the microbial reaction may be carried out using a reaction tank such as a fermenter, a culture tank, or an activated sludge aeration tank in a batch manner or in a continuous manner. Solid-liquid separation of a mixed liquid containing microorganisms is usually carried out as a separate unit operation by drawing the mixed liquid out of the reaction tank once the microbial reaction is completed, especially in the case of a continuous system. It is common that For example, yeast culture uses high-speed centrifugal concentration, alcohol fermentation uses sedimentation and filtration, wastewater treatment uses sedimentation, and methane fermentation uses sedimentation to perform solid-liquid separation. Furthermore, re-solid-liquid separation in wastewater treatment and re-solid-liquid separation in methane fermentation are carried out using centrifugation and filtration. However, these solid-liquid separation operations are performed in a separate location from the reaction tank in which the microbial reaction takes place, requiring a location for the installation of equipment for solid-liquid separation operations, and the overall size of the equipment increases. There is a problem in that the area and volume required for installing the entire device become large.

Specifically, when performing solid-liquid separation by sedimentation, it is necessary to install a settling tank. For example, in a wastewater treatment facility using the activated sludge method, normal domestic wastewater (BOD approximately 20
mH/f, COD approx. 200mg//, suspended solids 200
mg/f>, the volume of the activated sludge aeration tank as a reaction tank is 6-8)
~5) It is necessary to install a settling tank with a volume of X0 m3, and it is also necessary to install a pump for returning the settled sludge. Furthermore, in yeast cultivation, alcohol fermentation, etc., it is necessary to install a centrifugal separator, a filtration device, etc. separately from the reaction tank. In the batch method, a reaction tank may be used instead of a precipitation tank to perform solid-liquid separation by precipitation, and in this case, solid-liquid separation can be performed within the reaction tank. However, in this case, if the reaction tank is used as a settling tank, it is necessary to increase the volume of the reaction tank in order to lengthen the residence time in the reaction tank, which increases the size of the entire device as well as the installation of the entire device. The problem is that the area and volume required to do so become large.

[Object of the invention] The present invention has been made in view of the above points, and there is no need to provide solid-liquid separation equipment at a location separate from the reaction tank, and the entire device can be formed and installed compactly. The main purpose is to reduce the required area and volume, and also to completely perform solid-liquid separation and promote microbial reactions in the reaction tank. The purpose is to efficiently carry out microbial reactions while increasing the concentration of microorganisms in the tank.

[Disclosure of the Invention] The present invention provides a reaction tank 1 for carrying out a microbial reaction.
The centrifugal concentrator 2 includes a rotor 4 into which a mixed liquid 3 containing microorganisms in a tank is fed and separates the mixed liquid 3 into solid and liquid by centrifugal force caused by rotation, and an outer periphery of the rotor 4. A slit 5 provided in the section for returning the mixed liquid 3 concentrated by solid-liquid separation from inside the rotor 4 into the tank, and a slit 5 for discharging the separated liquid separated by solid-liquid separation from inside the rotor 4 to the outside of the tank. The first invention provides a microbial reaction tank equipped with a concentrating mechanism characterized by being formed with a tube 6, and a centrifugal concentrator 2 is installed in the reaction tank 1 in which a microbial reaction is carried out. The centrifugal concentrator 2 consists of a rotor 4 into which a mixed liquid 3 containing microorganisms in a tank flows and separates the mixed liquid 3 into solid and liquid using centrifugal force due to rotational drive; a slit 5 for returning the mixed liquid 3 from the rotor 4 to the tank;
A discharge pipe 6 discharges the separated liquid separated by solid-liquid separation from inside the rotor 4 to the outside of the tank, an inflow lower and slit 5 through which the mixed liquid 3 flows into the rotor 4, and a discharge pipe 6 through which the separated liquid in the rotor 4 is discharged. A second invention provides a microbial reaction tank equipped with a concentration mechanism characterized in that it is formed with a filtering material 9 installed in the rotor 4 between the outflow port 8 and the outflow port 8, The centrifugal concentrator 2 is configured by attaching a centrifugal concentrator 2 to a reaction tank 1 in which a microbial reaction is carried out.The centrifugal concentrator 2 receives a mixed liquid 3 containing microorganisms in the tank and separates the mixed liquid 3 into solid and liquid using the centrifugal force generated by the rotational drive. a slit 5 provided on the outer periphery of the rotor 4 for returning the mixed liquid 3 concentrated by solid-liquid separation from inside the rotor 4 into the tank;
It is formed with a discharge pipe 6 for discharging the separated liquid separated by solid-liquid separation from the inside of the rotor 4 to the outside of the tank, and is rotated with the rotation of the rotating shaft 1o that rotationally drives the rotor 4. A third invention provides a microorganism reaction tank equipped with a concentration mechanism, characterized in that a mixed liquid stirring means 11 is provided attached to the centrifugal concentrator 2, and in addition, the mixed liquid in the reaction tank 1 containing microorganisms is 3 flows into the rotor 4 of the centrifugal separator 2 installed in the reaction tank 1, and the mixed liquid 3 is separated into solid and liquid by the centrifugal force generated by the rotary drive of the rotor 4, and the mixed liquid 3 that has been solid-liquid separated and concentrated is The separated liquid separated from the mixed liquid 3 by solid-liquid separation is returned to the reaction tank 1 through a slit 5 provided on the outer periphery of the rotor 4, and the separated liquid is discharged from the inside of the rotor 4 to the outside of the tank through a discharge pipe 6. A microbial reaction method in a microbial reaction tank equipped with a concentration mechanism characterized by increasing the concentration of the mixed liquid 3 in the reaction tank 1 and allowing the microorganisms in the mixed liquid 3 to act on the liquid to be treated supplied to the reaction tank 1. This is the fourth invention.

In the first aspect of the present invention, a centrifugal concentration device 2 is provided in the reaction tank 1.
Since the reactor 1 and the equipment for solid-liquid separation can be integrated, the entire apparatus can be made compact, and the equipment for solid-liquid separation can be integrated. Since the concentrated liquid of the mixed liquid 3 is returned from the rotor 4 into the reaction tank 1 and the separated liquid is discharged outside the reaction tank 1, the concentration of the mixed liquid 3 in the reaction tank 1 is increased and the reaction jw
1 can be made smaller in volume. Further, in the second aspect of the present invention, since the filter material 9 is provided within the rotor 4, solid-liquid separation can be reliably performed by the filtration action of the filter material 9. Further, in the third aspect of the present invention, the mixed liquid 3 can be stirred or scattered by the mixed liquid stirring means 11, and the microbial reaction within the reaction tank 1 can be promoted. In addition, in the fourth aspect of the present invention, the microbial concentration of the mixed liquid 3 in the reaction tank 1 can be increased, and the highly concentrated microorganisms can efficiently cause a microbial reaction in the liquid to be treated.

The present invention will be explained in detail below with reference to Examples. 1 and 2 each show an embodiment of the apparatus of the present invention, in which a centrifugal concentrator 2 is installed approximately in the center of a reaction tank 1 configured as a fermenter, a culture tank, an activated sludge aeration tank, etc. is the installation. A rotor 4 formed hollow inside this centrifugal concentrator 2
is provided with a vertical rotation shaft 10 that protrudes above and below, respectively. The rotating shaft 10 is formed by a hollow pipe, and the rotating shaft 10 protruding upward is connected to the output shaft 14 of the electric motor 13 installed in the box 17 in the upper part of the reaction tank 1 by a flange joint, and is connected to the box 17. Bearing 1
5, and a rotating shaft 10 protruding downward is supported by a mechanical seal type bearing 16 on a pedestal 18 provided at the bottom of the reaction tank 1, and connected to the discharge pipe 6 while ensuring water sealing. be. In the centrifugal concentrator 2 shown in FIG. 1, the rotor 4 has an external shape that resembles a pair of upper and lower cones joined together, and a slit 5 is provided in the upper and lower middle portions of the outer periphery to allow communication between the inside and the outside of the rotor 4 over the entire circumference. The rotor 4 is arranged below the surface of the mixed liquid 3 in the reaction tank 1. In the centrifugal concentrator 2 shown in FIG. 2, the rotor 4 has an inverted conical outer shape, and a slit 5 is provided on the outer periphery of the upper end of the rotor 4 to allow the rotor 4 to pass inside and out in a series of 11 parts over the entire circumference. is arranged near the water surface of the mixed liquid 3 in the reaction tank 1. Further, the discharge pipe 6 is connected to the inside of the rotor 4 via the rotating shaft 10 as described above, and this discharge pipe 6 is led to the outside of the reaction tank 1. The rotor 4 has an inflow lower formed at its axial center, and an outlet 8 provided at the axial center of the rotor 4 at a position vertically apart from the inflow lower allows the inside of the discharge pipe 6 and the inside of the rotor 4 to be connected. are communicated. Further, in the centrifugal concentrator 2 shown in FIG. 1, a mixed liquid stirring means 11 formed of stirring blades 11a is attached to the rotating shaft 10, and in the centrifugal concentrator 2 shown in FIG. The mixed liquid stirring means 11 formed by is attached.

A liquid to be treated, such as a culture solution or waste water to be treated, is continuously fed into the reaction tank 1 through an inflow pipe 19, and a mixed liquid 3 containing microorganisms in the reaction tank 1 enters the rotor 4 from the inflow lower. The rotor 4 is rotated by an electric motor 13 at a circumferential speed of about 10 m/sec or more, and the mixed liquid 3 is rapidly separated into solid and liquid within the rotor 4 by its centrifugal force. The mixed liquid 3 concentrated by solid-liquid separation in the rotor 4 is discharged from the rotor 4 through the slit 5 provided on the outer periphery of the rotor 4 and returned to the reaction tank. The separated liquid obtained by separating solid content such as microorganisms from the mixed liquid 3 is discharged from the outlet 8 to the discharge pipe 6,
It is discharged to the outside of the reaction tank 1 through a discharge pipe 6. In this way, the mixed liquid 3 in the reaction tank 1 is concentrated in the rotor 4 of the centrifugal concentrator 2 and returned to the reaction tank 1, so the mixed liquid 3 in the reaction tank 1 has a high microbial concentration and a suspended solids concentration. It is maintained at about 5,000 to 50,000 mg/f. Therefore, the nutrients in the liquid to be treated, such as the culture liquid and wastewater to be treated, which are sent into the reaction tank 1 from one inflow pipe, are immediately bioadsorbed onto the surface of the suspended matter, absorbed by microorganisms, and formed into cavities. become. Moreover, at this time, the mixed liquid stirring means 11 formed by the stirring blades 11a and the stirring plate 11b is rotated together with the rotor 4 which is rotationally driven by the rotating shaft 10, and the mixed liquid 3 is stirred or scattered by the stirring action on the water surface. As a result, the liquid mixture 3 is in a completely mixed state, which promotes absorption of nutrients by microorganisms and conversion to copper. Further, if the centrifugal concentrator 2 continues to operate continuously, the concentration of the mixed liquid 3 in the reaction tank 1 will gradually increase, and the microbial reaction will be inhibited or the fluidity will decrease. Therefore, the concentration of mixed liquid 3 was set to 500C1-5 above.
It is necessary to adjust and maintain a concentration range of 0,000 mg/I. For this purpose, the reaction tank 1 has a concentrated mixed liquid discharge pipe 2.
0 is attached so that the concentration of the mixed liquid 3 in the reaction tank 1 can be adjusted by discharging the mixed liquid 3 at the appropriate time.

Next, the construction of the rotor 4 of the centrifugal concentrator 2 will be explained. The one shown in FIG. 3(a) is of a type in which a plurality of upper and lower separation swash plates 21 are provided inside the rotor 4, and the rotor 4 is rotated below the water surface of the mixed liquid 3, and the inflow lower is connected to the rotor 4. When installed above the separating swash plate 21, the separation swash plate 21 is arranged so as to be inclined diagonally downward toward the outside. In the case shown in FIG. 3(b), a plurality of upper and lower separation swash plates 21 are provided inside the rotor 4, so that the rotor 4 is rotated near the water surface of the mixed liquid 3, and a mixed liquid stirring means is provided on the outer peripheral surface of the rotor 4. 1
The stirring plate 1 as a stirring plate 1] is of a type in which a is attached, and when the inflow lower is provided below the rotor 4, the separation swash plate 21 is inclined diagonally upward toward the outside. Placed. 3(a) and (b), the mixed liquid 3 flowing into the rotor 4 from the inflow lower
is guided by the separation swash plate 21 (solid line arrow) and flows under the solid-liquid separation effect due to the centrifugal force caused by the rotation of the rotor 4. The separation swash plate 21 separates the flow into solids and liquid, resulting in the flow shown by the broken line. The concentrated liquid mixture 3 containing a large amount of solid content is discharged from the slit 5, and the separated liquid containing almost no solid content is discharged from the outlet 8 to the discharge pipe 6 as indicated by the double line arrow. In this way, the separation swash plate 2 can promote solid-liquid separation and centrifugal separation of the mixed liquid 3. The ones shown in FIGS. 3(e) and 3(d) are of the same type as those shown in FIG. 3(a) and FIG. 3(b), respectively. Open foam etc.5
A filter material 9 formed into an umbrella shape with a filter material having pores of about 0 to 100 mesh or less is attached.
The interior of the rotor 4 is partitioned and separated into a portion communicating with the slit 5 and the inflow lower and a portion communicating with the outlet 8. In this figure 3 (cod>), the mixed liquid 3 that has flowed into the rotor 4 from the inflow lower flows while undergoing solid-liquid separation action due to the centrifugal force caused by the rotation of the rotor 4 (solid line arrow), but the solid content is Since it cannot pass through the filter medium 9, only the separated liquid that does not contain solids passes through the filter medium 9 as shown by the double line arrow, and the separated liquid flows out from the outlet 8 to the discharge pipe 6. The concentrated liquid mixture 3 containing a large amount of solids is discharged from the slit 5 as indicated by the broken line arrow.

In this way, the separated liquid is discharged after the solid content has been filtered and removed by the filter medium 9, and complete solid-liquid separation can be performed. In addition, the above figure 3(b)
In (e), the filtering material 9 is formed into an umbrella shape and used, but the filtering material 9 is divided into two parts in the rotor 4: one part communicates with the slit 5 and the inflow lower, and the other part communicates with the outlet port 8. As long as it has a shape that can be partitioned and separated -16
The shape can be arbitrary, such as small or cylindrical. The rotor 4 of each type shown in FIGS. 3(a) to 3(d) can be selected and used depending on the conditions of the mixed liquid 3 in the reaction tank 1. Of course, the structures shown in FIGS. 3(a) to 3(d) are examples of the structures when the rotor 4 of the centrifugal separator 2 used in the present invention is put into practical use, and the structures are limited to these structures. isn't it.

Install the centrifugal separator w2 in the reaction tank 1 as described above,
By separating the mixed liquid 3 in the reaction tank 1 into solid and liquid and returning the concentrated mixed liquid 3 to the reaction tank 1, the entire device can be made compact and the required installation area and installation volume of the entire device can be reduced. can be made smaller. In other words, when solid-liquid separation is performed in a location other than reaction tank 1, a sedimentation tank, etc. must be installed in addition to reaction tank 1 when performing solid-liquid separation by precipitation separation as described above, and a centrifugal When performing solid-liquid separation by separation or filtration, it is necessary to install a centrifugal separator or a filtration device in a location other than the reaction tank 1, but with the present invention, these devices are no longer necessary, and these devices can be attached. Since there is no necessary force to do this, the entire device is made into a compact structure to reduce the area and volume required for installation of the entire device. By separating the solid and liquid in Step 4 and returning the concentrated mixed liquid 3 to the reaction tank 1 and discharging the separated liquid to the outside of the reaction tank 1, the concentration of microorganisms and activated sludge in the reaction tank can be reduced. Conventionally, the microbial dry matter concentration in the mixed liquid 3 in the reaction tank 1 in which this type of microbial reaction is carried out is usually 0.2% to 1% at most.
It is difficult to increase this concentration. For example, it is attempted to increase the concentration of the mixed liquid 3 in the reaction tank 1 by precipitating the mixed liquid 3 in a settling tank, performing solid-liquid separation and concentrating the mixed liquid 3, and returning this to the reaction tank 1.
When the concentration of the mixed liquid 3 becomes about 2% or more, it becomes difficult to separate the mixed liquid 3 into a liquid part and a settling part in the settling tank. It is not possible to significantly increase the concentration of In addition, it is attempted to increase the concentration of the mixed liquid 3 in the reaction tank 1 by performing solid-liquid separation by means of filtration or centrifugation and returning the slurry separated from the mixed liquid 3 to the reaction tank 1, but the dry matter of the separated slurry When the concentration exceeds 5%, its fluidity deteriorates and it becomes difficult to return it to the reaction tank 1. Moreover, during this operation, the characteristics of the microorganisms tend to deteriorate due to self-digestion and putrefaction. It is practically difficult to greatly increase the concentration of the mixed liquid 3 in the liquid mixture 3. In contrast, in the present invention, the mixed liquid 3 is highly concentrated by centrifugation using the rotor 4 of the centrifugal separator 2 in the reaction tank 1, and this concentrated mixed liquid 3 is directly returned to the reaction tank 1. The concentration of the mixed liquid 3 in the tank 1 can be easily increased to about 2 to 5%.

By increasing the concentration of microorganisms in the mixed liquid 3 in the reaction tank 1 in this way, assuming that the biochemical reaction rate per cell of microorganisms remains the same, the amount of reaction in a given tank volume can be significantly increased. I can do it. For example, when alcoholic fermentation of glucose is carried out, as the concentration of microorganisms, that is, yeast, in reaction tank 1 increases, the number of yeast cells in the same volume increases, and the concentration of glucose increases in proportion to the number of yeast cells. can be supplied to produce alcohol,
This means that fermentation efficiency can be significantly increased. In addition, in the case of activated sludge treatment of wastewater, the concentration of suspended solids in the mixed liquid 3 in the activated sludge aeration tank as the reaction tank 1 is usually 3.
000mg/f, but if the concentration of microorganisms in the mixed liquid 3 is increased and maintained at, for example, about 9000mg/f, the aeration capacity will be approximately tripled and the volume of the aeration tank will only need to be about 173mm. Therefore, the volume of the aeration tank is (6 to 8)
Qm3, the same level of processing as before can be achieved even if the volume is reduced to (2~3)XQm3.
”

Furthermore, as described above, in the present invention, nutrients can be supplied to the reaction tank 1 without requiring operations such as drawing out the mixed liquid 3 in the reaction tank 1, concentrating it, and then returning it to the reaction tank 1. However, if the slurry concentration in the mixed liquid 3 reaches 5% or more, the fluidity of the mixed liquid 3 in the reaction tank 1 will decrease. As a result, the efficiency of centrifugal concentration by the centrifugal concentrator 2 also decreases. Moreover, in an aerobic microbial reaction, oxygen must be supplied according to the concentration of the mixed liquid 3, but this supply of oxygen becomes difficult as the concentration of the mixed liquid 3 increases. For this reason, depending on the conditions, it is possible to perform aerobic or anaerobic digestion to control the slurry concentration in the mixed liquid 3, but it is also possible to control the slurry concentration in the reaction tank 1 in order to maintain the slurry concentration in the mixed liquid 3 at a predetermined concentration. The mixed liquid 3 must be drawn out as appropriate, and the drawn mixed liquid 3 must be subjected to solid-liquid separation for disposal or reuse. Here, in the present invention, the mixed liquid 3 in the reaction tank 1 has been concentrated by the centrifugal concentrator 2 and has already undergone preliminary concentration, so it is extracted by filtration or centrifugation at high speed. Solid-liquid separation of the mixed liquid 3 can be easily carried out using a compact device.

In addition, when separating the mixed liquid 3 in the reaction tank 1 into solid and liquid,
If precipitation separation or filtration is used, the separation will be insufficient in the case of precipitation separation, and in the case of filtration, there will be many troubles such as clogging of the filter medium. In particular, in sedimentation separation in activated sludge treatment of wastewater, it is difficult for solids to settle due to swelling (bulking), and it is difficult to obtain a clear sedimentation liquid by disassembly. Mixed liquid 3 is separated by centrifugal separator 2 in tank 1.
By performing centrifugal separation, the separation of the mixed liquid 3 can be significantly accelerated by the centrifugal action, and a clear separated liquid can always be obtained, eliminating troubles such as swelling and disassembly. In particular, by attaching the filtering material 9 in the rotor 4 of the centrifugal separator 2 (second invention of the present invention: described in claim 2), the effect of solid-liquid separation of the mixed liquid 3 is enhanced by the filtering material 9. Even if the effect of centrifugal concentration decreases or becomes defective for some reason, it is possible to always discharge only a clear separated liquid in which the solid content has been completely filtered out.

At this time, the solid content clogging of the filter medium 9 is self-cleaned by the centrifugal force generated when the filter medium 9 rotates together with the rotor 4, and it is possible to prevent troubles such as clogging of the filter medium 9 from occurring. .

In addition, by providing the mixed liquid stirring means 11 on the rotating shaft 1o or the rotor 4 of the centrifugal separator 2 (third invention of the present invention:
(Recited in Claim 3), by stirring the mixed liquid 3 or scattering the mixed liquid 3 into the gas layer by stirring the mixed liquid 3 near the water surface, the biochemical reaction within the reaction tank 1 can be significantly accelerated. It can be promoted. In other words, it is desirable to bring the nutrients supplied into the reaction tank 1 into contact with the microbial cells in the tank as evenly as possible in order to promote biochemical reactions. The stirring blades 11a and the stirring plates 11b facilitate centrifugal concentration and stirring and mixing of the liquid mixture 3 at the same time, allowing the nutrients to come into uniform contact with the microbial cells and promoting biochemical reactions.

The mixed liquid 3 is stirred by creating a swirling flow in the tank by encouraging upward flow or horizontal flow. In the case of an aerobic reaction, by scattering the mixed liquid 3 into the air by the mixed liquid stirring means 11, aeration by so-called mechanical stirring can be performed and the aerobic reaction can be promoted. Furthermore, in the case of an anaerobic reaction such as methane fermentation, by forming the reaction tank 1 as a closed tank and scattering the mixed liquid 3 into the upper air layer of the reaction tank 1, oxygen in the mixed liquid 3 is removed and the air layer is reduced. The mixed liquid 3 can be maintained in a reduced state with hydrogen sulfide, etc. contained therein, and the anaerobic reaction can be promoted. Furthermore, scum generated on the surface of the mixed liquid 3 by scattering of the mixed liquid 3 can also be crushed.

In addition, in the past, reactions and treatments proceeded efficiently in a reaction tank 1 such as a fermentation tank, a culture tank, or an activated sludge aeration tank, and the mixed liquid 3 transferred and discharged from the reaction tank 1 was separated into solid and liquid and then re-entered into the reaction tank. However, in the present invention, many driving devices and mechanical devices are required for aeration, stirring, transfer, solid-liquid separation (sedimentation, centrifugal concentration, filtration, etc.), and return. The rotor 4 of the centrifugal concentrator 2 can perform centrifugal concentration and filtration, the mixed liquid stirring means 11 attached to the centrifugal concentrator 2 can perform stirring and aeration, and the slit 5 of the rotor 4 can perform return. In principle, the operation can be performed with a single drive device or mechanical device, which is extremely energy-saving. Here, the circumferential speed of rotation of the rotor 4 only needs to be 10 m/sec or more as described above. For example, in the case of a rotor 4 with a diameter of about 250 mm,
It is sufficient to rotate the rotor 4 at about 10Q Q rpm or more, and by using a general-purpose 4-pole or 2-pole electric motor 13, the rotation axis 1 of the rotor 4 is connected to the output shaft 14 of the electric motor 1a13.
It is sufficient to directly connect 0, and no special equipment is required.

Therefore, it is economical in terms of equipment, and the operating power cost does not increase.

Next, the application of the present invention to a specific device will be explained.

The apparatus and method of the present invention can be effectively used in the alcoholic fermentation of sugars for production or in the production of baker's yeast from molasses or the like.

For example, 100% aqueous solution containing 10% glucose or fructose
In order to convert alcohol into nearby alcohol, conventionally a fermenter for alcohol fermentation was prepared, the tank was filled with sugar solution, seed cultured yeast was added to it, and fermentation was carried out in batch mode for 8 days or more.
The grown yeast is precipitated in a fermenter or filtered,
This is done through solid-liquid separation, such as by centrifugation.

On the other hand, when the apparatus shown in FIG. 1 of the present invention is used (the rotation of the rotor 4 is set at a circumferential speed of about 50 m/sec), the mixed liquid 3 in the reaction tank 1 as a fermenter contains yeast that has grown. is concentrated and remains until the suspended solids concentration is about 5,000 to 50,000 mg/Il, and by continuously supplying a 10% sugar aqueous solution to the fermenter, the fermentation reaction immediately proceeds and converts sugar into alcohol. It is possible to convert. Here, the amount of sugar loaded depends on the fermentation capacity of yeast per unit time per unit organism, the concentration of yeast as suspended matter maintained in the fermenter, the separation function of centrifugal concentrator 2, etc. , compared to conventional alcoholic fermentation, it is possible to make fermentation completely continuous,
Moreover, it becomes possible to significantly reduce the volume of the fermenter. In the conventional batch method in which seed cultured yeast is added, the average suspended solids concentration from the start to the end of fermentation is 1500 mg.
/j! However, in the device of the present invention that can concentrate the mixed liquid 3, this concentration can be reduced to 6000 mg/j! If the fermentation time is maintained at a certain level or higher, the required fermentation time can be calculated to be reduced to less than 174 mm compared to the conventional method.If a fermenter with a volume equivalent to 2 days' worth of sugar solution is used, the yield can be maintained as usual. It is thought that alcoholic fermentation can be carried out continuously. At this time, in order to prevent the concentration of suspended solids in the fermenter from becoming too high, it is desirable to draw out the mixed liquid 3 little by little, perform solid-liquid separation outside the tank, and return the separated liquid to the fermenter.

Alcohol fermentation waste liquid, food processing waste liquid, livestock sewage, human waste,
Methane fermentation of sewage sludge and other materials has been widely put into practical use. The apparatus and method of the present invention can also be effectively used in this methane fermentation.

In medium-temperature methane fermentation of waste liquid or sludge with an organic matter concentration of 1 to 2%, conventionally a fermenter is used that can be kept at a temperature of 30 to 37 degrees Celsius and has a retention period of around 30 days with stirring, and is continuously or semi-continuously exposed to the fermentation tank. This is done by supplying a treatment liquid and fermenting it.

In this case, the mixed liquid is separated by sedimentation inside or outside the fermenter to separate the desorbed liquid and the digested sludge, and the desorbed liquid is sent to secondary treatment, and the digested sludge has a concentration of suspended solids in the mixed liquid in the methane fermentation tank. The standard practice is to leave only 0.5 to 1.5% (in the case of sewage sludge, it may be more than this) and dewater the rest.

On the other hand, when the device shown in FIG. 2 of the present invention is used and the rotor 4 shown in FIG. 11, separation and discharge of the desorbed liquid by the rotor 4 and discharge pipe 6, and return of the digested sludge to the tank can be performed in a closed tank. In other words, the rotational circumferential speed of the rotor 4 is approximately 30 m.
/second, the effect of stirring by the mixed liquid stirring means 11 can be made comparable to that of the conventional mechanical stirring method, and the centrifugal concentrator 2 returns the thick slurry of digested sludge to the tank. This makes it possible to increase the concentration of suspended solids in the mixed liquid 3 to 3 to 5%. Methane fermentation also depends on the actions of various microorganisms mixed in the digested sludge, especially the methane bacteria group, and by enriching them, methane fermentation can be speeded up 2 to 6 times compared to conventional methods. Furthermore, if the concentration of organic matter in the liquid to be treated is 1 to 2%, it is thought that it will be sufficiently decomposed and methane gas can be recovered within 5 to 15 days of retention. This methane fermentation requires heat retention, but since the volume of the tank can be significantly reduced, energy consumption for heat retention can also be reduced. In addition, the thickened mixed liquid is drawn out as appropriate for solid-liquid separation,
It is desirable to control the concentration of the mixed liquid in the tank.

The activated sludge method,
Contact biofilm methods such as the trickling bed method, rotating disk method, and packed circulation filter bed method are used, but the activated sludge method is the most popular.

If you try to completely treat organic wastewater using this activated sludge method, you will need large aeration tanks and sedimentation tanks, and the activated sludge method is also prone to biological problems such as bulking and disintegration. Power consumption is also large.

In this regard, by applying the apparatus and method of the present invention, extremely remarkable effects can be achieved. That is, for example, the device shown in FIG. 2 is used in an activated sludge aeration tank, and the rotation speed is set to about 30 km/sec in circumferential speed (see FIG. 3).
Using the rotor 4 of d), domestic wastewater with BOD, COD, and suspended solids of about 200 mg/l each is Q m ' /
When processing at a processing speed of hr, the following effects can be expected.

1) Inside the aeration tank used as the reaction tank 1, the mixed liquid 3 can be separated into solid and liquid by the centrifugal concentrator 2, and the sludge can be returned directly into the aeration tank, and the separated liquid can be discharged to the outside of the tank through the discharge pipe 6. In addition, a settling tank following the aeration tank and a mechanism for returning settled sludge are completely unnecessary.

Therefore, the volume of the sedimentation tank can be reduced by 2 to 5) XQm3.

2) Increase the concentration of mixed liquid 3 in the aeration tank with centrifugal compaction W2,
Suspended solids (MLSS) in mixed liquid 3 are 9000 to 1200
If maintained at 0 mg/l, the MLS of a conventional standard activated sludge aeration tank would be 53,000 mg/l! It is possible to increase the BOD volume load to the aeration tank by 3 to 4 times.
．． 8-2,'4 kg/m3-day.

Therefore, the conventional standard OD volume load (approximately 0.6 kg/
The aeration tank has a volume of (6 to 8)×Qm3 (less than m3·day), but it becomes possible to form and use the aeration tank with a volume of about 2×Qm3, which is 173 to 1/4 of this. Above 1
), the tank volume is reduced to 1 compared to the conventional one.
It can be set to 75 or less.

3) Aeration in the aeration tank has traditionally been carried out by aeration methods or mechanical agitation methods, which reduces power consumption.
Although it is expressed in kWh per OD1'kg, the mechanical stirring method is generally considered to be advantageous in terms of power consumption. Therefore, it can be said that the apparatus of the present invention, which mechanically stirs the mixed liquid 3 using the mixed liquid stirring means 11 which is rotated at the same time as centrifugal concentration is performed by the centrifugal concentrator 2, is advantageous because it can perform efficient stirring.

4) Swelling and disintegration are likely to occur when solid-liquid separation is performed by sedimentation separation, but since solid-liquid separation is performed by centrifugal concentration using the centrifugal concentrator 2, these swelling and disintegrations can be prevented even under conditions that cause swelling and disintegration. Clear separation liquid can be separated without fear. This means that the most difficult problem in managing conventional activated sludge treatment facilities can be solved.

5) By using the rotor 4 provided with the filtering material 9 as shown in FIG. 3(d), suspended solids are filtered out by the filtering material 9, so that the amount of suspended solids in the solid-liquid separated liquid is reduced. be able to. For example, by using a 100-mesh nylon cloth as the filter material 9, suspended solids in the separated liquid can be extremely reduced. The filtering material 9 tends to become clogged with suspended solids, but even if suspended solids accumulate on the surface of the filtering material 9, since the filtering material 9 is also rotated with the rotation of the rotor 4, the centrifugal force at this time will cause the suspended solids to become clogged. The substance is detached from the surface of the filter medium 9 and no disturbance occurs.

6) Domestic wastewater and industrial wastewater contain a lot of nitrogen, so even if normal sludge activation treatment is performed to lower BOD and COD, it is not sufficient as a treatment, and nitrogen removal may also be required. . Here, nitrogen is oxidized by aeration in activated sludge treatment and becomes nitrous acid and nitric acid. Afterwards, when aeration is stopped and the redox potential is lowered, these become nitrogen gas and volatilize into the air. It has been known.

This oxidation and denitrification occur more easily as the MLSS increases. In the apparatus and method of the present invention, if centrifugal concentration and stirring are stopped for a short time and aeration is repeated, oxidation and denitrification can easily proceed because the MLSS is higher than before. Usually, the rotation of the rotor 4 and the mixed liquid stirring means 1
If the stirring in step 1 is stopped for about 5 minutes per hour, the purpose of denitrification can be sufficiently achieved.

Next, a specific example of a wastewater treatment device will be shown.

4(a) and 4(b) show a total aeration centrifugal separation type combined treatment apparatus, in which an aeration tank 23 constituting the reaction tank 1 is provided in the tank, and the aeration tank 23 shown in FIG. A centrifugal concentrator 2 similar to that of the present invention is installed. In this case, an inverted triangular pyramid base 2 is provided with a mixed liquid stirring means 11 on a rotating shaft 10.
A stirring plate 11b is formed protruding from the outer periphery of the water tank 4, and the mixed liquid stirring means 11 is arranged near the water surface. A basket-shaped screen 25 is provided below the tip of one of the inflow pipes, and the tip of the discharge pipe 6 connected to the rotor 4 is a disinfection tank equipped with a tower 26 filled with a disinfectant, such as a Hyclone packed tower. It leads to 27. In the figure, 28 is a manhole. In this treatment device, wastewater is sent into an aeration tank 23 from one inflow pipe, and coarse suspended matter such as garbage is first removed by a screen.

Then, the wastewater is treated with activated sludge in the aeration tank 23 by the action of the centrifugal concentrator 2 and mixed liquid stirring means 11, and the separated liquid separated into solid and liquid in the rotor 4 is sent to the disinfection tank 27 through the discharge pipe 6. It is disinfected in the disinfection tank 27 and discharged from the outflow pipe 29.

FIGS. 5(a) and 5(b) show a separate aeration and centrifugation type combined treatment apparatus, in which the inside of the tank is partitioned by an overflow plate 30 to separate the aeration tanks 23 and 35 that constitute the reaction tank 1. A tank 31 is formed, and an aeration tank 23 is formed.
A centrifugal concentrator 2 similar to that shown in FIG. 2 is installed inside. In the figure, 32 is a scum stopper.

In this treatment device, wastewater is first sent from an inflow pipe 19 to a separation tank 31, where garbage and the like are sedimented and separated. Then, the wastewater in the separation tank 31 is advected over the upper end of the overflow plate 30 into the aeration tank 23, where it is treated in the same way as that shown in FIG. 4, and further disinfected in the disinfection tank 27. [Effects of the Invention] As mentioned above, the first invention of the present invention is one in which a centrifugal concentrator is installed in a reaction tank in which a microbial reaction is carried out, and this centrifugal concentrator is A rotor into which the mixed liquid containing microorganisms in the tank flows and separates the mixed liquid into solid and liquid using centrifugal force due to rotational drive, and a slit provided on the outer periphery of the rotor that returns the mixed liquid concentrated by solid-liquid separation from inside the rotor to the tank. and a discharge pipe for discharging the separated liquid separated from the mixed liquid by solid-liquid separation from inside the rotor to the outside of the tank, so there is no equipment for solid-liquid separation inside the reaction tank. A certain centrifugal concentration device can be integrated, and there is no need to install a separate device for solid-liquid separation, and there is no need for return equipment from outside the tank to the inside of the tank, making the whole system compact. Moreover, since the concentrated liquid of the solid-liquid separated mixed liquid is returned into the reaction tank through the slit of the rotor, and the separated liquid is discharged from the reaction tank through the discharge pipe, the mixed liquid in the reaction tank is It is possible to increase the concentration of microorganisms in the mixed solution and increase the reaction efficiency of the microorganisms in the mixture.
Due to the high efficiency of the microbial reaction within the reaction tank, the volume of the reaction tank can be reduced. Therefore, the area and volume for installing the device can be reduced.

In addition to the first invention, a second invention of the present invention provides a filter between the inlet and slit through which the mixed liquid flows into the rotor and the outlet through which the separated liquid in the rotor flows out into the discharge pipe. Because the material is attached to the rotor, the solid content separated from solid and liquid by centrifugation in the rotor can be prevented from being discharged through the discharge pipe by the filtering action of the filter material, ensuring a clear separated liquid. The filter material is rotated together with the rotor, and the surface of the filter material self-cleans due to centrifugal force during rotation, which prevents the filter material from becoming clogged. This is something that can prevent this from happening. Therefore, solid-liquid separation of the mixed liquid can be reliably performed.

Further, in addition to the first invention, a third invention of the present invention provides a method for stirring a mixed liquid, in which a mixed liquid stirring means is attached to the centrifugal concentrator and is rotated with the rotation of a rotating shaft that rotationally drives a rotor. The mixed liquid in the reaction tank can be stirred or dispersed by means, and the microbial reaction can be promoted by equalizing the action between the microorganisms and nutrients due to stirring and by contacting the mixed liquid with the air layer due to scattering. I can do it. However, when the mixed liquid stirring means rotates the rotor, it can be driven to rotate at the same time with the same power as the rotational power of the rotor, and there is no need for special power to drive the mixed liquid stirring means, which simplifies the device. Energy saving effects can be obtained.

In addition, the fourth aspect of the present invention is to cause the mixed liquid in the reaction tank containing microorganisms to flow into the rotor of a centrifugal separator installed in the reaction tank, and to separate the mixed liquid into solid and liquid by the centrifugal force generated by the rotational drive of the rotor, The solid-liquid separated and concentrated mixed liquid is returned to the reaction tank through a slit provided on the outer periphery of the rotor, and the separated liquid separated from the mixed liquid by solid-liquid separation is discharged from the rotor to the outside of the tank through a discharge pipe. By doing this, the concentration of the mixed liquid in the reaction tank is increased, and the microorganisms in this mixed liquid are allowed to act on the mixed liquid supplied to the reaction tank. Therefore, the mixed liquid is concentrated by solid-liquid separation in the rotor. The solid-liquid separated liquid is directly returned from the slit of the herotor in the reaction tank, and the solid-liquid separated liquid is discharged to the outside of the tank through a discharge pipe. By repeating this operation in the reaction tank, the mixed liquid in the reaction tank can be easily reduced in concentration. By increasing the concentration of microorganisms in the mixed liquid, it is possible to increase the efficiency of the biological reaction of the microorganisms to the liquid to be treated.

[Brief explanation of drawings]

Figures 1 and 2 are schematic sectional views showing embodiments of the device of the present invention, and Figures 3 (a), (b), (c) and (d) are cross-sectional views showing embodiments of the rotor used in the present invention, respectively. figure,
FIGS. 4(a) and 4(b) are a schematic front sectional view and a schematic plan sectional view showing an embodiment in which the apparatus of the present invention is applied to wastewater treatment;
Figures (a) and (b) are a schematic front sectional view and a schematic plan sectional view showing another embodiment in which the device of the present invention is applied to wastewater treatment, and
7 and 7 are flow diagrams of microbial reactions, respectively. 1 is a reaction tank, 2 is a centrifugal concentration device, 3 is a mixed liquid, 4 is a rotor, 5 is a slit, 6 is a discharge pipe, 7 is an inlet, 8 is an outlet, 9 is a filter material, 1o is a rotating shaft, ]1 is a mixed liquid stirring means.

Claims (4)

[Claims] (1) A centrifugal concentrator is installed in a reaction tank in which a microbial reaction is carried out.The centrifugal concentrator consists of a rotor that receives the mixed liquid in the tank containing microorganisms and separates the mixed liquid into solid and liquid using the centrifugal force generated by rotation. , a slit provided on the outer circumference of the rotor that returns the mixed liquid concentrated by solid-liquid separation from inside the rotor to the tank, and a discharge pipe that discharges the separated liquid separated from the mixed liquid by solid-liquid separation from inside the rotor to the outside of the tank. A microbial reaction tank equipped with a concentration mechanism, characterized in that it is formed by comprising: (2) A centrifugal concentrator is installed in a reaction tank in which a microbial reaction takes place, and the centrifugal concentrator consists of a rotor that receives the mixed liquid in the tank containing microorganisms and separates the mixed liquid into solid and liquid using centrifugal force generated by rotation. , a slit provided on the outer circumference of the rotor that returns the mixed liquid concentrated by solid-liquid separation from inside the rotor to the tank, and a discharge pipe that discharges the separated liquid separated from the mixed liquid by solid-liquid separation from inside the rotor to the outside of the tank. and a filtering material installed in the rotor between the inlet and slit through which the mixed liquid flows into the rotor and the outlet through which the separated liquid in the rotor flows out to the discharge pipe. A microbial reaction tank equipped with a concentration mechanism characterized by: (3) A centrifugal concentrator is installed in a reaction tank in which a microbial reaction takes place, and the centrifugal concentrator consists of a rotor that receives the mixed liquid in the tank containing microorganisms and separates the mixed liquid into solid and liquid using the centrifugal force generated by rotation. , a slit provided on the outer circumference of the rotor that returns the mixed liquid concentrated by solid-liquid separation from inside the rotor to the tank, and a discharge pipe that discharges the separated liquid separated from the mixed liquid by solid-liquid separation from inside the rotor to the outside of the tank. A concentrating mechanism characterized in that the centrifugal concentrating device is provided with mixed liquid stirring means that rotates with the rotation of a rotating shaft that rotationally drives the rotor. Equipped with a microbial reaction tank. (4) The mixed liquid in the reaction tank containing microorganisms is caused to flow into the rotor of a centrifugal separator installed in the reaction tank, and the mixed liquid is separated into solid and liquid by the centrifugal force generated by the rotation of the rotor, and the mixed liquid is separated into solid and liquid and concentrated. The mixed liquid in the reaction tank is returned to the reaction tank through a slit provided on the outer periphery of the rotor, and the separated liquid separated from the mixed liquid by solid-liquid separation is discharged from the rotor to the outside of the tank through a discharge pipe. increase the concentration of
A microbial reaction method in a microbial reaction tank equipped with a concentration mechanism, characterized in that microorganisms in this mixed liquid are made to act on a liquid to be treated that is supplied into the reaction tank.