JPS5942095A - Biological treatment of waste water containing organic material - Google Patents

Abstract

PURPOSE:To clean up biochemically polluted waste water of middle and high concn. without diluting the same by treating the waste water contg. org. polluting components of middle and low concn. in an anaerobic tank and an aerobic tank then adding the same to the waste water of middle and high concn. which is treated in the anaerobic tank. CONSTITUTION:The waste water of middle and low concn. contg. org. pollutants such as waste water of fishery processing, waste water of night soil or the like is first supplied into the 1st conditioning and anaerobic tank 1 contg. anaerobic bacteria such as lactic acid bacteria or the like where the waste water is treated; in succession, the water is treated in the 1st aerobic tank 2 contg. aerobic bacteria such as zooglea bacteria. The treated water is treated together with the waste water having pollution of middle and high concn. treated in the 2nd conditioning and anaerobic tank 3 in the 2nd aerboic tank 4, whereafter the aerobic sludge is separated by settling in a settling and separating tank 5. The treated water is added to the waste water from the tank 1. The activity of the waste water in the tank 1, 3 and the tanks 2, 4 is increased and the treatment is made possible without diluting the waste water having the pollution of middle and high concn.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a biological treatment method for wastewater containing organic substances, which can treat medium-high concentration wastewater without diluting it.

The inventors of this invention previously filed a patent application filed in 1986-115.
No. 715, a useful biological treatment method was proposed as an alternative to the biological treatment of wastewater containing organic substances by the conventional activated sludge method. The characteristics of this biological treatment method will be explained based on the flow sheets shown in Figures 1 and 2. First, as shown in Figure 1, medium- and high-concentration wastewater consisting of the same or similar pollutant components. Among the medium and low concentration wastewater, the medium and low concentration wastewater is sequentially sent from the first adjustment anaerobic tank 1 to the first aerobic tank 2, and then mixed with the medium and high concentration wastewater that has passed through the second adjustment anaerobic tank 3. The aerobic sludge separated in the sedimentation separation tank 5 is sent from the second aerobic tank 4 to the sedimentation separation tank 5, and the aerobic sludge separated in the sedimentation separation tank 5 is
It is a wastewater treatment circulation system that mixes medium and low concentration wastewater discharged from a regulating anaerobic tank 1 and returns it to a first aerobic tank 2, in which the anaerobic wastewater containing facultative anaerobic bacteria is Aeration and agitation suitable for generating anaerobic sludge in which bacteria are exposed is performed, and wastewater containing this anaerobic sludge and Zoogloea returned from the sedimentation separation tank 5 are
The aerobic sludge in which aerobic bacteria and anaerobic bacteria have become apparent is mixed to produce sludge, and by aeration and agitation in the first aerobic tank 2, aerobic bacteria are revealed and anaerobic bacteria are Anaerobic bacteria including facultative anaerobic bacteria generated by aerobic agitation of the latent aerobic sludge and wastewater containing this new aerobic sludge in the second adjustment anaerobic tank 3 is anaerobic. Sludge is generated by mixing wastewater containing sludge and aerated and agitated in the second aerobic tank 4 to make aerobic sludge in which aerobic bacteria become apparent again and anaerobic bacteria become latent, and this aerobic sludge is contained. The wastewater is sent to the sedimentation separation tank 5 and the aerobic sludge separated from the supernatant liquid is returned to the first aerobic tank 2 as described above, and the remaining aerobic sludge returned to the first aerobic tank 2 and the above-mentioned supernatant are The clear liquid is discharged to the outside of the wastewater treatment circulation system, and as shown in FIG. The first is mixed with the medium and low concentration wastewater produced.
In addition to being returned to the aerobic tank 2, it is also distributed and returned to the first adjusted anaerobic tank 1 and the second adjusted anaerobic tank 3.

Compared to the conventional activated sludge method, this biological treatment method is more effective than the conventional activated sludge method, in which aerobic bacteria contained in medium- and low-concentration wastewater treated under aerobic conditions become apparent and anaerobic bacteria become latent. New sludge produced by mixing pneumatic sludge with anaerobic sludge in which anaerobic bacteria contained in medium-high concentration wastewater, which is composed of the same or similar pollutant components as low-core nuclear wastewater, has become apparent, Since the pollutant components contained in the water are rapidly purified, there is no need to dilute it several tens of times when treating medium and high concentration wastewater as in the past.
This has the effect of making it possible to downsize each device and simplifying operation. Furthermore, since the amount of aeration in each aerobic tank and each adjusted anaerobic tank is significantly smaller than in the conventional activated sludge method, it has the advantage of reducing operating costs.

However, if there is a sudden change in the pollutant components or concentration of wastewater, changes in weather conditions, or other changes in physical and chemical conditions, the survival conditions for bacteria in the wastewater treatment circulation system may change due to these factors. This fluctuation makes it impossible to perform wastewater treatment smoothly, and as a result, there is a drawback that a great deal of effort is required to stabilize the wastewater treatment circulation system.

This invention was made in view of the above circumstances, and even when there is a sudden change in the pollutant components or concentration of wastewater, a change in weather conditions, or other physicochemical changes, the wastewater treatment cycle can be improved. The purpose is to stabilize the system and perform smooth wastewater treatment, and its characteristics are that the first and second regulating anaerobic tanks 1 and 3 and the first
, a part of the wastewater in the second aerobic tanks 2 and 4 is taken out to separate activation tanks, and the C/N ratio is adjusted and inorganic substances are added.
After performing aeration and stirring under the same conditions as in 3 and 4, the wastewater in each activation tank was transferred to each tank 1, 2, 3,
This is where I changed it back to 4.

The method of this invention will be explained in detail below with reference to FIG.

This method of the invention involves sequentially sending medium-low concentration wastewater from a first adjusted anaerobic tank 1 to a first aerobic tank 2, and then passing it through a second adjusted anaerobic tank 3 containing pollutant components that are the same as or similar to the medium-low concentration wastewater. The aerobic sludge separated in the sedimentation separation tank 5 is mixed with the medium and low concentration wastewater discharged from the first adjusted anaerobic tank 1 and sent from the second aerobic tank 4 to the sedimentation separation tank 5. In the wastewater treatment circulation system in which the wastewater is returned to the first aerobic tank 2,
, the activity of bacteria in the wastewater in the second adjusted anaerobic tanks 1 and 3 and the first and second aerobic tanks 2 and 4 is promoted.

In this invention, medium-high concentration wastewater and medium-bottom concentration wastewater consisting of the same or similar pollutant components include, for example, boiling liquid, blood juice, etc. in the marine product processing process of mackerel and sardines, and general process wastewater is referred to as medium-high concentration wastewater. This is called medium-low concentration wastewater. In addition, if raw human waste is considered medium-high concentration wastewater, general city sewage and diluted human waste fall under medium-low concentration wastewater. Furthermore, the medium-high concentration wastewater includes methane fermentation desorbed liquid in addition to the untreated raw liquid wastewater as described above.

Wastewater includes seafood processing wastewater, accumulated human waste wastewater, agricultural processing wastewater,
Any wastewater containing other organic substances can be treated by the method of the present invention, regardless of its type.

Among the bacteria that act in the wastewater treatment circulation system of this invention, aerobic bacteria include Zoogloea bacteria, other yeasts are also included, and anaerobic bacteria include facultative anaerobic bacteria that have some aerobic properties. sexual bacteria, such as lactic acid bacteria (L
actobacillus), Pediococcus (P
ediococcus), streptococcus (St
genus repto-coccus, Bacillus
Bacteria belonging to the genus S. lus) are essential, and other obligate anaerobic bacteria may also be included. When facultative anaerobic bacteria contain bacteria belonging to the genus Lactobacillus, specific effects described below are produced. These aerobic bacteria and anaerobic bacteria are previously introduced into the wastewater treatment circulation system before the system starts operating, and from then on, those that have grown naturally in the threads are used.

The medium-low concentration wastewater is sent in order from the first adjustment anaerobic tank 1 to the first aerobic tank 2, the second aerobic tank 4, and the sedimentation separation tank 5, and is composed of the same or similar pollutant components as the medium-low concentration wastewater. The medium-high concentration wastewater is mixed with the wastewater exiting the first aerobic tank 2 from the second adjustment anaerobic tank 3 and sent to the second aerobic tank 4 and sedimentation tank 5.

The medium-low concentration wastewater is collected in the first adjustment anaerobic tank 1, where operations such as equalizing the liquid, adding nutrients, and adjusting the pH are performed as necessary. Aerated and stirred. This aeration agitation is performed in the wastewater in order to proliferate anaerobic bacteria including facultative anaerobic bacteria living in the first adjusted anaerobic tank 1 and to generate anaerobic sludge in which these anaerobic bacteria are exposed. Since it provides a small amount of dissolved oxygen evenly, the amount of aeration per unit pollutant may be weak, usually about one-tenth or less of the amount of aeration in the first and second aerobic tanks 2 and 4. This has been found empirically and experimentally. This is because if a larger amount of aeration is performed, although the wastewater is sufficiently agitated, facultative anaerobic bacteria become inactive and anaerobic sludge is not produced. In addition, in this first adjustment anaerobic tank 1, a part of the wastewater in the tank is once guided to the activation tank 8 by the pump 7, and the C/N ratio is adjusted and inorganic substances are added. After aeration and agitation under the same conditions in the first regulating anaerobic tank 1 is performed using air sent from the blower 6, the wastewater in the activation tank 8 is returned to the first regulating anaerobic tank 1 again. The capacity of this activation tank 8 may normally be about 1/100 to 1/10 of the capacity of the first adjustment anaerobic tank.

Further, the C/N ratio is appropriately selected and adjusted within the range of 10 to 25 depending on the pollutant components of the wastewater. This adjustment of the C/N ratio is performed to activate the anaerobic bacteria contained in the wastewater and speed up their growth rate, but if the C/N ratio is high, it can be lowered by adding nitrogen components such as urea. If the C/N ratio is low, a carbon component such as waste molasses is added to increase it. Like the adjustment of the C/N ratio, the addition of inorganic substances is done to activate the anaerobic bacteria contained in the wastewater and increase their growth rate. A solution containing about 50% of other necessary salts is added to about 1/300 to 1/10 of the volume of the activation tank 8. The time for which the wastewater is retained in the activation tank 8 is approximately 10 times the division time of the oily anaerobic bacteria present in the wastewater.
Specifically, the standard residence time is about 2 hours and 30 minutes, but the residence time may be extended or shortened as necessary depending on the wastewater conditions or other reasons. The first adjustment anaerobic tank 1 to this activation tank 8
The wastewater in the activation tank 8 is supplied in a batch by a predetermined amount, subjected to the above treatment, and then the wastewater in the activation tank 8 is returned all at once to the first adjustment anaerobic tank 1 through so-called batch processing. is standard, but a fixed amount may be supplied continuously if the wastewater composition is not particularly suitable for the growth of anaerobic bacteria. As mentioned above, the anaerobic bacteria contained in the wastewater treated in the activation tank 8 have been activated and the state is most suitable for promoting microbial decomposition of organic matter. 1 By returning to the adjusted anaerobic tank 1,
Like the wastewater returned from the activation tank 8, the wastewater in the first adjustment anaerobic tank 1 is also in a state suitable for promoting microbial decomposition of organic matter, that is, a state in which the anaerobic bacteria in the wastewater are activated. The batch treatment of the wastewater in the activation tank 8 may be performed continuously depending on the composition of the wastewater, but it may be performed continuously only when there is a possibility that the treatment system will not be able to operate smoothly due to a change in the initial conditions of the wastewater. You may also do this by doing this. The temperature of the wastewater in the activation tank 8 is desirably within a range of ±10°C with respect to the temperature of the wastewater in the first adjustment anaerobic tank 1, but is most preferably 30°C or more and 32°C or less.

The medium and high concentration wastewater is collected in the second adjustment anaerobic tank 3, where, like the medium and low concentration wastewater, the wastewater is adjusted as necessary and aerated and agitated to expose anaerobic bacteria including oily anaerobic bacteria. anaerobic sludge is produced. Also, in this second adjustment anaerobic tank 3, an activation tank 9 similar to the first adjustment anaerobic tank 1 is used.
A part of the wastewater in the tank is once guided to the activation tank 9 by the pump 10, and the C/N ratio is adjusted and inorganic substances are added.
After aeration and agitation under the same conditions as in the above are performed using air sent from the blower 6, the wastewater in the activation tank 9 is returned to the second adjustment anaerobic tank 3 again.

The wastewater containing anaerobic sludge in which anaerobic bacteria have become apparent and exits from the first adjustment anaerobic tank 1 is mixed with aerobic sludge in which aerobic bacteria have become apparent and anaerobic bacteria have become latent, which is returned from the sedimentation separation tank 5. The sludge is then put into the first aerobic tank 2 together with the new sludge generated. The mixing ratio of the two is such that the solids concentration is equal or a little more aerobic sludge is mixed. These two different types of sludge have contradictory physical and chemical properties, and among these contradictory physical and chemical properties, the affinity between aerobic sludge and anaerobic sludge due to Coulomb force and Van der Waals force is Due to the additive effects such as the increase in sludge properties and the formation of certain macromolecular bonding reactions between the two sludges and the adhesive force due to the mucous membrane formed by the aerobic bacteria, 2.
A strong cohesive force between the two sludges is created. Due to this strong cohesive force and the effect of incorporating dissolved components as coagulation progresses, new sludge containing both aerobic and anaerobic bacteria is generated, and the purification effect of wastewater is promoted. . Incidentally, aerobic sludge and anaerobic sludge produced from wastewater composed of the same or similar pollutant components have strong vertical concentration as described above, but on the other hand, aerobic sludge and anaerobic sludge produced from wastewater containing the same or similar pollutant components have a strong vertical concentration as described above. It has been experimentally found that almost no cohesive force occurs between aerobic sludge and anaerobic sludge. This indicates that the aggregation reaction is not simply due to Coulomb force or van der Waals force, but also the presence of a certain type of polymer bonding reaction.

Also, in this first aerobic tank 2, the first and second anaerobic tanks 1,
An activation tank 11 similar to No. 3 is provided, and a part of the waste water in the tank is once guided to the activation tank 11 by a pump 12 to adjust the C/N ratio and add inorganic substances.
After performing aeration and agitation under the same conditions in the first aerobic tank 2 for a predetermined period of time using air sent from the blower 6, the wastewater in the activation tank 11 is returned to the first aerobic tank 2 again. The capacity of the activation tank 11 relative to the first aerobic tank 2, the preferred C/N ratio range, the method of adjusting the C/N ratio, the addition of inorganic substances, and the retention of wastewater in the activation tank 11 for aeration and agitation. The time, batch processing is standard, etc.
and activation tanks 8 and 9 provided in the second adjustment anaerobic tanks 1 and 3
is the same except that the purpose of installing this activation tank 11 is to activate aerobic bacteria. Regarding the temperature conditions inside the activation tank 11, it is desirable that the range is ±5°C with respect to the temperature of the waste water in the first aerobic tank 2, but the most desirable range is 25°C or more and 27°C or less. Here, the first
and activation tanks 8 and 9 provided in the second adjustment anaerobic tanks 1 and 3
The difference in temperature from the internal wastewater is due to the difference in the response of the target bacterial group to external temperature conditions.

The sludge generated in this way is collected in the first aerobic tank 2.
By aerating and stirring in the activation tank 11 and further activating the aerobic bacteria, the aerobic sludge becomes an aerobic sludge in which the aerobic bacteria are exposed and the anaerobic bacteria are latent, and then the sludge is discharged from the first aerobic tank 2 together with the wastewater. The sludge is mixed with wastewater containing anaerobic sludge discharged from the second adjusted anaerobic tank 3, and is then introduced into the second aerobic tank 4 together with sludge produced for the same reason as described above. The mixing ratio of the two is such that the solids yield is equal or a little more aerobic sludge is mixed. The generation of this new sludge promotes the purification effect of the wastewater containing anaerobic sludge discharged from the second regulating anaerobic tank 3. In addition, this second aerobic tank 4 is also provided with an activation tank 13 similar to the first and second adjustment anaerobic tanks 1 and 3 and the first aerobic tank 2, and once a part of the wastewater in the tank is removed. , is guided to the activation tank 13 by the pump 14, and the C/N ratio is adjusted and inorganic substances are added.
After aeration and agitation under the same conditions in the aerobic tank 4 are performed using air sent from the blower 6, the wastewater in the activation tank 13 is returned to the second aerobic tank 4 again.

The conditions of this activation tank 13 are the same as those of the activation tank 11 provided in the first aerobic tank 2. The sludge put into the second aerobic tank 4 has both aerobic bacteria and anaerobic bacteria, but it is aerated and stirred in the second aerobic tank 4, and aerobic bacteria are removed in the activation tank 11. By further activating the sludge, aerobic bacteria become apparent and anaerobic bacteria become activated, resulting in aerobic sludge that is sent to the sedimentation separation tank 5.

In the sedimentation separation tank 5, the aerobic sludge settles and is separated from the supernatant liquid, and the supernatant liquid is discharged as treated water to the outside of this wastewater treatment circulation system. It is mixed with wastewater containing anaerobic sludge discharged from the first adjusted anaerobic tank 1 and returned to the first aerobic tank 2. The remaining aerobic sludge that is not returned is separated into solid and liquid by the sludge dehydrator 16 and discharged to the outside of the wastewater treatment circulation system.

In addition, the aerobic sludge contains Zooglaia (Zooglaia), which was introduced into the wastewater treatment circulation system before its operation started, or which grew naturally afterward.
Aerobic bacteria, including bacteria of the genus zoogloea, have become evident, and anaerobic bacteria, including facultative anaerobic bacteria, have become latent. Also, similar to the first adjustment anaerobic tank 1, the first aerobic tank 2,
Aeration and agitation in the second aerobic tank 4, second adjustment anaerobic tank 3, and each activation tank 8, 9, 11, 13 is also performed by air sent from the blower 6, but instead of this, other means can be used. Of course, aeration and stirring may also be used.

Furthermore, in the first adjusted anaerobic tank 1 and the second adjusted anaerobic tank 3, anaerobic bacteria including facultative anaerobic bacteria added before the start of operation proliferate despite the inflow and outflow of wastewater due to aeration and agitation. Anaerobic sludge is continuously generated, but if the pollution concentration of wastewater decreases for various reasons, it may become impossible for the anaerobic bacteria to grow.
As shown in the figure, a wastewater treatment circulation system can be provided in which the aerobic sludge separated in the sedimentation separation tank 5 is also returned to the first adjustment anaerobic tank 1 and the second adjustment anaerobic tank 3. In the case of this system, the anaerobic bacteria that are latent in the aerobic sludge can become apparent and multiply in the first adjusted anaerobic tank 1 and the second adjusted anaerobic tank 3 due to the aeration and agitation described above. be. Therefore, in this system, the wastewater discharged from the first adjusted anaerobic tank 1 and the second adjusted anaerobic tank 3 contains anaerobic sludge in which anaerobic bacteria have become apparent and aerobic bacteria have become latent. It is in this system that the wastewater containing this anaerobic sludge and the aerobic sludge returned from the sedimentation separation tank 5, in which aerobic bacteria are exposed and anaerobic bacteria are latent, are mixed to generate new sludge. The same is true.

Also, in this system, the first and second adjustment anaerobic tanks 1 and 3
Also, in the same manner as in the above system, the wastewater in the first and second aerobic tanks 2 and 4 is taken out to the activation tanks 8, 9, 11, and 13, and all bacteria in the wastewater are activated.

In the two wastewater treatment circulation systems mentioned above, when Lactobacillus bacteria are included as facultative anaerobic bacteria, the strong sludge flocculation effect further increases due to the action of these Lactobacillus bacteria. The production of sludge is promoted, and the progress of putrefaction due to the proliferation of putrefaction bacteria under anaerobic conditions in the first adjusted anaerobic tank 1 and the second adjusted anaerobic tank 3 is delayed, and therefore, the generation of putrid odor is also prevented. It has the effect of

As is clear from the above explanation, in the method of the present invention, of medium-high concentration wastewater and medium-low concentration wastewater consisting of the same or similar pollutant components, the medium-low concentration wastewater is transferred from the first adjustment anaerobic tank 1 to the first preferred anaerobic tank 1. After the water is sequentially sent to the air tank 2, it is mixed with the medium-high concentration wastewater that has passed through the second adjustment anaerobic tank 3, and sent from the second aerobic tank 4 to the sedimentation separation tank 5. A wastewater treatment circulation system in which sludge is mixed with medium-low concentration wastewater discharged from the first adjustment anaerobic tank 1 and returned to the first aerobic tank 2, or the aerobic sludge separated in the sedimentation separation tank 5 in the system is In a wastewater treatment circulation system that mixes with medium and low concentration wastewater discharged from the first adjusted anaerobic tank 1 and returns it to the first aerobic tank 2, and also distributes and returns it to the first adjusted anaerobic tank 1 and the second adjusted anaerobic tank 3, Activation tanks 8, 9, 11, 1 in the first adjustment anaerobic tank 1, first aerobic tank 2, second adjustment anaerobic tank 3, and second aerobic tank 4
A portion of the wastewater in each tank 1, 2, 3, 4 is introduced into these activation tanks 8, 9, 11, 13 to activate the anaerobic bacteria or aerobic bacteria, and then the wastewater is reactivated. Since the water is returned to the original 11 tanks 1, 2, 3, and 4, the bacteria in each tank 1, 2, 3, and 4 become active, and the microorganisms contained in the wastewater become activated. In other words, the wastewater treatment system can be stabilized because the wastewater is adjusted to a state suitable for decomposing organic matter in the wastewater.

Therefore, when there is a sudden change in the pollutant components or concentration of wastewater, changes in weather conditions or other physicochemical changes can be adequately coped with, and wastewater treatment can be carried out smoothly and efficiently.

[Brief explanation of the drawing]

1 and 2 each show a flow sheet of a wastewater treatment circulation system without an activation tank, and FIGS. 3 and 4 each show an example of a flow sheet of the present invention. 1... First adjusted anaerobic tank, 2... First aerobic tank, 3...
- Second adjustment anaerobic tank, 4... second aerobic tank, 5... sedimentation separation tank, 8, 9, 11, 13... activation tank. Companion: Mihiko Tsuchibe Procedural amendment (spontaneous) Japan Patent Office opponent Kazuo Wakasugi 1, Indication of matter 9 Patent application No. 152308 1982, Title of invention Organic 12 [organisms in wastewater containing substances] Scientific processing method 3, relationship with the case of the person making the amendment (for patents) Name of person: Nobuyoshi Ukai 4, agent: 530 Tel: Osaka 06 (361) 383
1 Address: 2-21-5 Tayu-cho, Kita-ku, Osaka, Subject of amendment (1) Detailed explanation of the invention in the specification column 6, Contents of the amendment (11 Detailed explanation of the invention column ■ Specification No. 6 Correct “at the bottom” in the 19th line of the specification to “below”. ■ Correct “mid-bottom concentration” in the 8th line of the 9th line of the specification to “medium-low concentration”. ■ Correct the 16th shell of the specification Correct the 2nd line "2nd anaerobic tank" to 1st 2nd adjustment anaerobic tank. ■ Correct the 21st true line 2 of the specification to "J under" to "under".

Claims (4)

[Claims] 1. Of medium-high concentration wastewater and medium-low concentration wastewater consisting of the same or similar pollutant components, the medium-low concentration wastewater was sent from the first adjustment anaerobic tank to the first aerobic tank in order, and then passed through the second adjustment anaerobic tank. The mixture is mixed with the medium-low concentration wastewater and sent from the second aerobic tank to the sedimentation separation tank, and the aerobic sludge separated in the nuclear sedimentation separation tank is mixed with the medium-low concentration wastewater discharged from the first adjustment anaerobic tank. A wastewater treatment circulation system for returning to an aerobic tank, wherein the first
In the adjusted anaerobic tank, aeration and agitation suitable for generating anaerobic sludge in which anaerobic bacteria including total anaerobic bacteria are exposed is performed, and this anaerobic sludge is returned to the sinking wastewater from the sedimentation separation tank. Zoogloea
The aerobic sludge in which aerobic bacteria including bacteria of the genus are exposed and anaerobic bacteria are latent is mixed to produce sludge, and by aeration and stirring in the first aerobic tank, aerobic bacteria are exposed and anaerobic bacteria are latent. Furthermore, the anaerobic sludge in which anaerobic bacteria including facultative anaerobic bacteria, which is generated by aeration and agitation of the wastewater containing this new aerobic sludge and the second adjustment anaerobic tank, has become apparent. By mixing the containing wastewater to produce sludge and aerating and stirring it in a second aerobic tank, the aerobic sludge is made into an aerobic sludge in which aerobic bacteria are exposed again and anaerobic bacteria are latent, and further, the first adjusted anaerobic tank, Part of the wastewater in the second adjustment anaerobic tank, first aerobic tank, and second aerobic tank is taken out to separate activation tanks, and the C/N ratio is adjusted and inorganic substances are added. A method for biological treatment of wastewater containing organic substances, characterized in that after performing aeration and stirring under the same conditions as in each of the tanks, the wastewater in each activation tank is returned to the original tanks. . 2. 2. The method for biological treatment of wastewater containing organic substances according to claim 1, wherein the oily anaerobic bacteria are facultative anaerobic bacteria including bacteria of the genus Lactobacillus. 3. Among medium-high concentration wastewater and medium-low concentration wastewater containing the same or similar pollutant components, the medium-low concentration wastewater is sent from the first regulating anaerobic tank to the first aerobic tank in order, and then passing through the second regulating anaerobic tank. The aerobic sludge separated in the sedimentation separation tank is mixed with the medium and low concentration wastewater discharged from the first adjustment anaerobic tank and sent from the second aerobic tank to the sedimentation separation tank. A wastewater treatment circulation system that returns wastewater to an aerobic tank and also returns to a first adjusted anaerobic tank and a second adjusted anaerobic tank, wherein anaerobic bacteria including facultative anaerobic bacteria are manifest in the first adjusted anaerobic tank. At the same time, aerobic agitation suitable for producing anaerobic sludge is carried out, and aerobic bacteria including Zoogloea bacteria returned from the wastewater containing this anaerobic sludge and the sedimentation separation tank are brought to light and anaerobic sludge is generated. The aerobic sludge with latent bacteria is mixed to produce sludge, which is then aerated and stirred in the first aerobic tank to make aerobic sludge where aerobic bacteria are exposed and anaerobic bacteria are latent. Sludge is produced by mixing wastewater containing aerobic sludge with wastewater containing anaerobic sludge in which anaerobic bacteria including facultative anaerobic bacteria produced by aeration and agitation in a second adjustment anaerobic tank have become apparent. By aeration and agitation in the second aerobic tank, aerobic bacteria become apparent again and anaerobic bacteria become latent aerobic sludge.
Part of the wastewater in the aerobic tank and the second aerobic tank is taken out to separate activation tanks, and the C/N ratio is adjusted and inorganic substances are added, and in these activation tanks, the same as in each of the above tanks is used. A biological treatment method for wastewater containing organic substances, characterized in that after performing aeration and stirring under certain conditions, the wastewater in each activation tank is returned to the original respective tanks. 4. 4. The biological treatment method for wastewater containing organic substances according to claim 3, wherein the facultative anaerobic bacteria are facultative anaerobic bacteria including the genus Lactobacillus.