JPH04354596A - Aerobic self-granulated material and production thereof - Google Patents

Abstract

PURPOSE:To obtain a self-granulated material high in organic matter decomposi tion performance by entangling protozoa with aerobic filamentous bacteria and granulating them. CONSTITUTION:Self-granulated material 31 is formed by entangling filamentous bacteria 32 and protozoa 33 are incorporated therein. Since the whole body is microorganisms, organismic reactivity is superior in comparison with a mixture formed by a carrier bonding method and an microorganismic capsule produced by a comprehensive immobilization method. Further since this self- granulated material is formed of aerobic filamentous bacteria 32 and protozoa 32, organic matter decomposition performance is higher than the self-granulated material formed of the conventional anaerobic filamentous bacteria. The self- granulated material is very effective in treatment of organic drainage.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an aerobic self-granulated product and a method for producing the same.

0002

[Prior Art] The use of biotechnology has been actively researched and developed as a method for efficiently treating organic wastewater, but immobilization of microorganisms is particularly important because it allows the selective use of specific microorganisms and the ability to collect microorganisms at high density. It is attracting attention as an essential technology because of its ability to retain Conventional methods for immobilizing microorganisms at high density include the following methods. (2) Carrier binding method This method is a method in which microorganisms are physicochemically attached to the surface of a carrier, and is formed by mixing the carrier material and microorganisms under environmental conditions suitable for immobilization for a certain period of time. ■Crosslinking method This method is a method in which a reagent having two or more functional groups is added to microorganisms to form microorganisms into aggregates. (2) Entrapping immobilization method In this method, microorganisms are encapsulated in a gel lattice or covered with a polymer film. After mixing microorganisms and polymeric resin, it is made into a solid state through a gelation reaction such as polymerization reaction. Then, after coating the surface with another resin, the immobilized resin inside is melted to produce a microbial capsule with a polymer film. (2) Self-immobilization method This method is a method in which microorganisms are made into particles using the agglomeration function in which methane bacteria of the genus Methanothrix that have grown in filamentous growth under anaerobic conditions are entangled.

0003

However, the conventional method described above has the following drawbacks. That is, the mixture formed by the method (2) cannot be used effectively as a whole because it contains an inert material that does not have a biological reaction. In addition, if a material with a higher density than microorganisms is used as a carrier, it will easily deform due to its own weight when used in a packed bed reactor, and the fluid energy will be large when used in a fluidized bed reactor. Power costs are high. Method (2) requires special reagents, which increases production costs. Since the microbial capsule produced by the method (2) has a low microbial density, it is necessary to concentrate the microorganisms at a high density as a pretreatment, which is difficult to manipulate. The product produced by method (2) has low organic matter decomposition performance because it is made up of granular anaerobic microorganisms. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a self-granulated product that is low in production cost and has high organic decomposition performance, and a method for producing the same.

0004

[Means for Solving the Problems] In order to achieve the above object, the aerobic self-granulated product of the first invention is characterized in that aerobic filamentous bacteria and protozoa are entangled and granulated. Further, the method for producing an aerobic self-granulated product according to the second invention includes a step of blowing air into the activated sludge placed in a container and stirring it, and stopping the air blowing to allow microorganisms in the activated sludge to settle. A semi-continuous culturing process is carried out for a predetermined period of time, which consists of a step of allowing the microorganisms to settle, a step of removing the supernatant liquid after the microorganisms have settled, and a step of adding a solution containing nutrients for the microorganisms to the activated sludge from which the supernatant liquid has been removed. Repeatedly generate aerobic filamentous bacteria in the activated sludge,
The same semi-continuous culture process as described above is repeated for a predetermined period of time on the activated sludge in which the aerobic filamentous bacteria have been generated, and the aerobic self-granulated material in which the aerobic filamentous bacteria and protozoa are entangled and granulated is obtained. It is characterized by the fact that it occurs. Further, the method for producing an aerobic self-granulated product according to the third invention includes a step of blowing air into activated sludge placed in a container and stirring it, and stopping the air blowing to allow microorganisms in the activated sludge to settle. A semi-continuous culturing process is carried out for a predetermined period of time, which consists of a step of allowing the microorganisms to settle, a step of removing the supernatant liquid after the microorganisms have settled, and a step of adding a solution containing nutrients for the microorganisms to the activated sludge from which the supernatant liquid has been removed. The process is repeated to generate aerobic filamentous bacteria in the activated sludge, while adding a solution with lower nutrient concentration than the above solution instead of the above solution to the activated sludge placed in the above container and another container. The continuous culture process is repeated for a predetermined period of time to increase the number of sessile protozoa in the activated sludge, and a plate-like member is inserted into the activated sludge in which the number of sessile protozoa has increased, and the plate-like member is filled with the sessile protozoa. Activated sludge containing animals is attached, the activated sludge attached to the plate member is scraped off and mixed with the activated sludge in which the aerobic filamentous bacteria are generated,
The activated sludge is characterized by repeating the same semi-continuous culture process as described above for a predetermined period of time to generate an aerobic self-granulated product in which the aerobic filamentous bacteria and protozoa are entangled and granulated.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to illustrated embodiments. FIG. 1 is a flowchart showing an embodiment of the method for producing an aerobic self-granulated product of the present invention. This manufacturing method begins with 5,500 m of MLSS collected at a sewage treatment plant.
Returned sludge with a low density of approximately g/L is placed in a container (step S1), and semi-continuous culture is performed for about 2 months (step S2).
. In this semi-continuous culture, the following steps ① to ② are repeated in sequence. ■Blow air into the returned sludge and stir it. (
This air blowing is performed continuously for about 16 hours at a rate of 1 L/5 L/min. ) ■ Stop blowing air for about 8 hours to allow microorganisms in the sludge to settle. ■After the microorganisms have settled, remove the supernatant liquid. ■After that, a solution of skim milk as a substrate dissolved in water at a rate of 1.3 g/L,
Add approximately the same amount of supernatant liquid that was removed. When the above-mentioned semi-continuous culture is carried out for about two months, a large amount of aerobic filamentous bacteria (Sphaelotilus, etc.) is generated, and sludge containing protozoa is formed (Step S3). Then, the sludge in which a large amount of filamentous bacteria has been generated is further subjected to semi-continuous culture for about one week in the same manner as above (step S
4), an aerobic self-granulated material as shown in FIG. 4 is generated (step S5). This self-granulated material 31 is formed by the above-mentioned filamentous bacteria 32 intertwined with each other, and contains protozoa 33 therein. In this way, an aerobic self-granulated product can be produced by a simple method of semi-continuously cultivating returned sludge, so material and equipment costs can be reduced, and production costs can be lowered.

FIG. 2 is a flowchart showing another embodiment of the method for producing an aerobic self-granulated product of the present invention. In this manufacturing method, in steps S11 to S13, a large amount of aerobic filamentous bacteria is generated in the same manner as in steps S1 to S3 in the above embodiment,
It is allowed to precipitate (step S14). On the other hand, the same MLSS55 as above collected in another container.
00mg/L of low density sludge (step S15)
Continuously culture for ~2 and a half weeks (step S15). In this semi-continuous culture, the concentration of the skim milk solution is lower (for example, about 0.1 g/L) than in the semi-continuous culture in the above example.
The other conditions were the same as in the above example. This semi-continuous culture increases the number of sessile protozoa (genus Epistylus; many ciliates such as Epistylis sp.) in the sludge (step S17). Next, as shown in FIG. 3, plates 22 made of ceramic or the like having small irregularities on the surface are hung at intervals of 10 mm in the container 21, and the activated sludge 23 containing the sessile protozoa is deposited on the plates (step S18). Next, the plate 22 is taken out from the container 21, the activated sludge 23 adhering to the plate is scraped off, and the scraped activated sludge is mixed with the sludge in which a large amount of aerobic filamentous bacteria is generated (step S20). After that, semi-continuous culture similar to the semi-continuous culture in step S12 is performed for about one week (step S21). By doing so, the aerobic filamentous bacteria and sessile protozoa become entangled to form an aerobic self-granulated material similar to that shown in FIG. 4. This manufacturing method is similar to the manufacturing method in the above example,
Since the process is as simple as semi-continuous cultivation of returned sludge, material and equipment costs can be reduced, and manufacturing costs can be lowered.

[0007] In addition, since the self-granulated product produced by any of the above production methods is entirely composed of microorganisms, it contains fewer organisms than a mixture formed by a carrier binding method or a microbial capsule produced by an entrapping immobilization method. It has excellent reactivity and has a lower density than a mixture formed by a carrier bonding method, so it has the advantage of lower power costs when used in a fluidized bed reactor. In addition, since this self-granulated material is made of aerobic filamentous bacteria and protozoa, it has a higher organic decomposition performance than conventional self-granulated material made of anaerobic filamentous bacteria, and is effective in reducing organic wastewater. Very effective for processing.

[Effects of the Invention] As is clear from the above, the aerobic self-granulated product of the first invention is a granulated product in which aerobic filamentous bacteria and protozoa are entangled, so it is suitable for the treatment of organic wastewater. It is very effective. Further, in the method for producing an aerobic self-granulated product of the second invention, activated sludge placed in a container is semi-continuously cultured for a predetermined period of time to generate aerobic filamentous bacteria in the activated sludge, The activated sludge in which the filamentous bacteria have been generated is subjected to semi-continuous culture as described above for a predetermined period of time to generate aerobic self-granulated material in which the aerobic filamentous bacteria and protozoa are entangled and granulated. Compared to conventional microbial immobilization methods, this method requires fewer materials and equipment, and can lower manufacturing costs. Further, in the method for producing an aerobic self-granulated product according to the third invention, activated sludge placed in a container is cultured semi-continuously for a predetermined period of time to generate aerobic filamentous bacteria in the activated sludge, while Activated sludge placed in a separate container is subjected to semi-continuous culture for a predetermined period using a nutrient solution with a lower concentration than the nutrient solution used in the semi-continuous culture to increase the number of sessile protozoa in the activated sludge, A plate member is inserted into the activated sludge in which the sessile protozoa have increased, the activated sludge containing the sessile protozoa is adhered to the plate member, and the activated sludge adhering to the plate member is scraped off. The above-mentioned aerobic filamentous bacteria are mixed with the activated sludge in which they are generated, and the activated sludge is subjected to the same semi-continuous culture process as above for a predetermined period, so that the above-mentioned aerobic filamentous bacteria and sessile protozoa become entangled and form particles. Since aerobic self-granulated material is generated, similar to the production method of the second invention, less materials and equipment are required compared to the conventional microorganism immobilization method, and the production cost is reduced. be able to.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing one embodiment of the method for producing an aerobic self-granulated product of the present invention.

FIG. 2 is a flowchart showing another embodiment of the method for producing an aerobic self-granulated product of the present invention.

FIG. 3 is a diagram showing a state in which sludge containing sessile protozoa adheres to a plate in the above-mentioned another example.

FIG. 4 is a schematic enlarged view of an aerobic self-granulated product produced by the above production method.

[Explanation of symbols]

21... Container, 22... Board, 23... Sludge containing sessile protozoa, 31... Aerobic self-granulated material, 32... Aerobic filamentous bacteria, 33... Protozoa.

Claims (3)

[Claims] [Claim 1] An aerobic self-granulated product in which aerobic filamentous bacteria and protozoa are entangled and granulated. 2. A step of blowing air into the activated sludge placed in a container and stirring it, stopping the air blowing to settle the microorganisms in the activated sludge, and removing a supernatant liquid after the microorganisms have settled. A semi-continuous culture process consisting of a step of removing the supernatant liquid and a step of adding a solution containing nutrients for the microorganisms to the activated sludge from which the supernatant liquid has been removed is repeated for a predetermined period to create aerobic filamentous properties in the activated sludge. Bacteria are generated, and the same semi-continuous culture process as above is repeated for a predetermined period on the activated sludge in which the aerobic filamentous bacteria have been generated, resulting in aerobic sludge in which the aerobic filamentous bacteria and protozoa are entangled and granulated. A method for producing an aerobic self-granulated product that generates a self-granulated product. 3. A step of blowing air into and stirring activated sludge placed in a container, a step of stopping the air blowing to settle the microorganisms in the activated sludge, and a supernatant liquid after the microorganisms have settled. A semi-continuous culture process consisting of a step of removing the supernatant liquid and a step of adding a solution containing nutrients for the microorganisms to the activated sludge from which the supernatant liquid has been removed is repeated for a predetermined period to create aerobic filamentous properties in the activated sludge. While generating bacteria, the above semi-continuous culture step of adding a solution with a lower concentration of nutrients than the above solution instead of the above solution to the activated sludge placed in the above container and another container is repeated for a predetermined period, and the activated sludge is incubated. sessile protozoa, inserting a plate-like member into the activated sludge in which the sessile protozoa have increased, and adhering the activated sludge containing the sessile protozoa to the plate-like member; The activated sludge adhering to the sludge is scraped off and mixed with the activated sludge in which the aerobic filamentous bacteria are generated, and the activated sludge is subjected to the same semi-continuous culture process as above for a predetermined period of time to produce the aerobic filamentous bacteria. A method for producing an aerobic self-granulated material in which bacteria and protozoa are entangled to generate aerobic self-granulated material.