JP2017029925A - Sludge volume reduction method, and activated sludge treatment apparatus of membrane separation type using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an activated sludge treatment apparatus and a method of a membrane separation type which do not require a cost for large-scale renovation work or the like, and can control and reduce an excess sludge amount by a simple method.SOLUTION: An activated sludge treatment apparatus of membrane separation type includes: a biological reaction tank which biologically processes organic waste water; a membrane separation unit for separating organic waste water purified in the biological reaction tank into purified water and activated sludge; a fungivorous bacterium culture tank which regenerates excess sludge generated in the biological reaction tank into activated sludge, and is equipped with aeration means for culturing fungivorous bacteria under an aerobic condition; sludge returning means for sending activated sludge generated in the fungivorous bacterium culture tank to the biological reaction tank, in which excess sludge is regenerated into activated sludge by culturing fungivorous bacteria in excess sludge in the fungivorous bacterium culture tank, and furthermore regenerated activated sludge is repeatedly used in the biological reaction tank.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sludge volume reduction method and a membrane separation type activated sludge treatment apparatus using the same.

  Membrane bioreactor (MBR) uses activated sludge containing microorganisms to decompose organic matter, nitrogen components, phosphorus components, etc. in wastewater such as sewage in a reaction tank, and then a membrane separation unit This is a technology for solid-liquid separation of purified water and microorganisms. In this way, the purified water discharged out of the system by the membrane separation type activated sludge treatment apparatus becomes a high-quality treated water. On the other hand, activated sludge is mainly composed of aerobic microorganisms, and microorganisms in the activated sludge grow depending on the operation time of the membrane separation type activated sludge treatment apparatus. Conventionally, activated sludge proliferated excessively in a membrane separation type activated sludge treatment apparatus has been disposed of as excess sludge in order to keep the activated sludge concentration constant. In addition to the excess sludge discarded in this way, the sludge waste discharged from other factories is collectively called sludge, but these sludges account for 43% of industrial waste by type. Therefore, controlling and reducing excess sludge volume was one of the important issues in MBR operation management.

Here, as a promising method for sludge volume reduction, there is a method of physically crushing microorganisms in sludge by subjecting excess sludge to pressure jet treatment (Patent Document 1). However, this method requires a new high-pressure jet injection system and a large-scale renovation work.
In addition, a method has been devised in which bacteria predatory protozoa are added to treat bacteria that are thought to cause a decrease in MBR processing ability (Patent Document 2). However, in this method, since predatory organisms are added from the outside, there is a concern that the balance of bacteria in the activated sludge changes greatly and the reactor function is lowered.

JP 2001-314877 A JP 2007-260664 A

  In view of the above-described problems, the present invention provides a membrane separation type activated sludge treatment apparatus that does not require cost for large-scale repair work and the like, and an apparatus and method that can control and reduce the amount of excess sludge by a simple method. Offering is an issue.

  Here, the method disclosed in Patent Document 1 is a method applied to an activated sludge treatment apparatus that does not employ a membrane separation type system. In an activated sludge treatment apparatus that does not employ a membrane separation type system, a certain amount of activated sludge is also discharged when purified water is discharged out of the system. On the other hand, in the membrane separation type activated sludge treatment apparatus, unless the excess sludge is taken out from the biological reaction tank, the excess sludge is accumulated in the biological reaction tank, so that the organic matter concentration in the excess sludge becomes relatively high. Moreover, as mentioned above, when employ | adopting the method of patent document 1, it is necessary to newly incorporate a high pressure jet injection system in an activated sludge processing apparatus. In addition, in the method of Patent Document 1, since the microorganisms in the activated sludge are not killed, the increase in concentration due to the grown microorganisms itself is not solved. Therefore, the method of patent document 1 also had the subject that it does not know whether it functions repeatedly also about the excess sludge in the membrane separation type | formula activated sludge processing apparatus from which a density | concentration becomes comparatively high. Therefore, the present inventors examined a volume reduction method of excess sludge that can be applied to excess sludge having a high concentration.

To date, the present inventors have operated a pilot scale MBR under various conditions, and have studied changes in the microbial composition in the activated sludge and associated changes in wastewater treatment capacity. As a result, the following important findings were found.
(I) Mycophagous bacteria are present as resident bacteria in activated sludge (ii) The amount of microorganisms in activated sludge increases in correlation with the amount of organic matter added, but is constant at a certain value, and for a certain period After a lapse, it starts to decrease. During this period, mycophagous bacteria grow rapidly in the activated sludge.
(Iii) When the amount of organic matter to be added is reduced, the amount of microorganisms in the activated sludge is reduced, but even during this period, mycophagous bacteria grow rapidly.

  Based on these findings, the present inventors maintained aerobic conditions in the tank containing excess sludge and restricted the amount of organic matter. Surprisingly, microorganisms that require organic matter are killed and lysed. In addition, the present inventors have found that the excess sludge can be reduced by decomposing these inactivated microorganisms by the bacteriophage bacteria present in the excess sludge. As a result, the present inventors preferentially proliferate mycophagous bacteria residing in the MBR activated sludge, and develop an apparatus and method that can reduce excess sludge by preying and decomposing inactive activated sludge microorganisms. It came to offer.

That is, the present invention is as follows.
One embodiment of the present invention provides:
[1] a biological reaction tank for biologically treating organic wastewater;
A membrane separation unit for separating the organic wastewater purified in the biological reaction tank into purified water and activated sludge;
A bacteriophage bacteria culture tank for regenerating surplus sludge generated in the biological reaction tank into activated sludge, comprising aeration means for culturing bacteriophage bacteria under aerobic conditions; ,
A membrane-separated activated sludge treatment apparatus comprising sludge return means for sending activated sludge regenerated in the bacteriophage bacteria culture tank to the biological reaction tank,
By culturing the bacteriophage bacteria in the excess sludge in the bacteriophage bacteria culture tank, the excess sludge is regenerated into activated sludge, and the regenerated activated sludge is repeatedly used in the biological reaction tank. The present invention relates to a membrane separation type activated sludge treatment apparatus.

Moreover, in one embodiment of the membrane separation type activated sludge treatment apparatus of the present invention,
[2] The present invention further comprises an organic matter inflow control means for controlling the inflow of organic matter to the bacteriophage bacterium culture tank.
Moreover, in one embodiment of the membrane separation type activated sludge treatment apparatus of the present invention,
[3] The bacteriophage bacterium culture tank further includes means for measuring the amount of organic matter.
Moreover, in one embodiment of the membrane separation type activated sludge treatment apparatus of the present invention,
[4] The bacteriophage bacterium belongs to the family Xanthomonadaceae, the bacteriophage bacterium belonging to the family Bdellovibrionaceae, the mycophagous bacterium belonging to the order Myxococcales, the phagocytic bacterium belonging to the class Sphingobacteriia, the phagocytic bacterium belonging to the class Flavobacteriia, and , Characterized in that it is at least one bacterium selected from the group of mycophagous bacteria belonging to the class Cytophagia.
Moreover, in one embodiment of the membrane separation type activated sludge treatment apparatus of the present invention,
[5] The culture of the bacteriophage bacteria in the bacteriophage bacteria culture tank is carried out for at least 7 days.
In addition, what has combined the characteristic for every embodiment regarding the membrane separation type | formula activated sludge processing apparatus of this invention in combination is also contained in the membrane separation type | formula activated sludge processing apparatus of this invention.

According to another aspect of the present invention, the present invention provides:
[6] A method of regenerating surplus sludge generated in the membrane separation type activated sludge method into activated sludge,
A method comprising culturing surplus sludge under aerobic conditions and under the condition that no organic matter is added from the outside to the surplus sludge,
The present invention relates to a regeneration method characterized by culturing bacteriophage bacteria in excess sludge by the culture and decomposing organic matter in the excess sludge by the bacteriophage bacteria.
Here, in one embodiment of the reproduction method of the present invention,
[7] The bacteriophage bacteria cultivated by the above-mentioned culturing process belong to the family Xanthomonadaceae, bacteriophages belonging to the family Bdellovibrionaceae, bacteriophages belonging to the family Myxococcales, bacteriophages belonging to the class Sphingobacteriia, Flavobacteriia It is characterized by being at least one bacterium selected from the group of mycophagous bacteria and mycophagous bacteria belonging to the class Cytophagia.
In one embodiment of the playback method of the present invention,
[8] The culturing step is performed for at least 7 days.
A combination of a plurality of features in each embodiment of the reproduction method of the present invention is also included in the reproduction method of the present invention.

According to another aspect of the present invention, the present invention provides:
[9] A membrane-separated activated sludge method including a step of biologically treating organic wastewater using the activated sludge regenerated by the regeneration method according to any one of [6] to [8] above .

  According to the membrane-separated activated sludge treatment apparatus of the present invention, excess sludge can be easily reduced in a bacteriophage bacteria culture tank. As a result, it is possible to reduce the amount of excess sludge discarded, and it is possible to use the regenerated activated sludge again for biological treatment.

FIG. 1 is a schematic view of a three-tank polycarbonate membrane separation activated sludge treatment apparatus used in Example 1 below. FIG. 2 shows a perspective view of a 3-tank polycarbonate membrane separation activated sludge treatment apparatus used in Example 1 below. FIG. 3 is an embodiment of the membrane separation activated sludge treatment apparatus of the present invention, and is a schematic diagram of a membrane separation activated sludge treatment apparatus in which a bacteriophage bacteria culture tank is provided separately from a biological treatment tank. Show. FIG. 4 (a) and FIG. 4 (b) are one embodiment of the membrane separation activated sludge treatment apparatus of the present invention, in which a mycophagous bacterial culture tank is provided separately from the biological treatment tank. The perspective view in embodiment of a separation activated sludge processing apparatus is shown, respectively. FIG. 5 is a graph (ML (a)) showing a time-dependent change of MLSS when a wastewater treatment operation is performed using a membrane separation activated sludge treatment apparatus under the conditions described in Example 1, and the most during the operation period. A graph showing the change in relative abundance of the top 10 microorganisms with a high increase in relative abundance (FIG. 5 (b)), and a table showing phylogenetic information on the top 10 microorganisms (FIG. 5 ( c)). FIG. 6 is a graph (FIG. 6 (a)) showing a time-dependent change in MLSS when a wastewater treatment operation is performed using a membrane separation activated sludge treatment apparatus under the conditions described in Example 2, and the most during the operation period. A graph showing the change in relative abundance of the top 10 microorganisms with a high relative abundance increase (FIG. 6 (b)), and a table showing phylogenetic information on the top 10 microorganisms (FIG. 6 ( c)). FIG. 7 is a graph (FIG. 7 (a)) showing a time-dependent change of MLSS when a wastewater treatment operation is performed using a membrane separation activated sludge treatment apparatus under the conditions described in Example 3, which is the most during the operation period. A graph showing the relative abundance change of the top 10 microorganisms having a high relative abundance increase (FIG. 7B), and a table showing phylogenetic information on the top 10 microorganisms (FIG. 7 ( c)).

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the form shown in FIG. 1, the membrane separation type activated sludge treatment apparatus 1 has three biological reaction tanks 2, 8, and 10. The biological reaction tank 2 is connected to an inflow system of wastewater for supplying organic wastewater, and organic wastewater such as sewage flows into the biological reaction tank 2 via the pump 3a. The organic wastewater that has flowed into the biological reaction tank 2 is mixed with activated sludge and the organic matter is decomposed by biological treatment. At this time, an air blower 4a, a diffuser tube 5a, and a flow meter 6a are installed in the biological reaction tank 2, and the inside of the biological reaction tank 2 is always kept in an aerobic condition. The biological reaction tank 2 is connected to the biological reaction tank 8, and the mixture of the organic waste water and the activated sludge in the biological reaction tank 2 flows into the biological reaction tank 8 through the connection pipe 7. An air blower 4b, an air diffuser 5b, and a flow meter 6b are also installed in the biological reaction tank 8, and the inside of the biological reaction tank 8 is always kept in an aerobic condition. This further promotes biodegradation of organic matter in the wastewater. The biological reaction tank 8 is connected to the biological reaction tank 10, and the mixture of the organic waste water and the activated sludge in the biological reaction tank 8 flows into the biological reaction tank 10 through the connection pipe 9. An air blower 4c, a diffuser tube 5c, and a flow meter 6c are also installed in the biological reaction tank 10, and the inside of the biological reaction tank 10 is always kept in an aerobic condition. The biological reaction tank 10 is also provided with a membrane separation unit 11 and a discharge system for separating the wastewater purified by biological treatment and activated sludge. In the discharge system, a transmembrane pressure gauge 12, a pump 3b, and a flow meter 6d are installed. Wastewater purified by biological treatment flows out from the membrane separation unit 11 to the discharge system and is discharged out of the system as treated water. The biological reaction tank 10 has a sludge return pipe 13 and a pump 3c for returning the activated sludge to the biological reaction tank 2, and the activated sludge is repeatedly used in the membrane separation type activated sludge treatment apparatus 1. The

  Here, the membrane-separated activated sludge treatment apparatus of the present invention includes a bacteriophage bacteria culture tank. The bacteriophagous bacteria culture tank is a tank for regenerating the activated sludge from the microorganisms in the activated sludge which have grown and become excess sludge. The regeneration of the excess sludge in the mycological bacteria culture tank is performed by limiting the addition of further organic substances from the outside and culturing the mycophagous bacteria in the excess sludge under aerobic conditions. Here, many microorganisms in the excess sludge are killed and lysed by restricting the increase of organic substances from the outside with respect to the excess sludge in the bacteriophage bacteria culture tank. The bacteriophage bacteria present in the excess sludge grow and proliferate by utilizing and decomposing these inactivated microorganisms. As a result, the mycophagous bacteria grow, but the organic matter concentration in the excess sludge can be reduced as a whole.

  The bacteriophage bacteria culture tank can be installed as a tank separate from the biological reaction tank, or at least one of the biological reaction layers can be used as the bacteriophage bacteria culture tank. In one embodiment shown in FIG. 1, at least one of the biological reaction tanks can function as a mycophagous bacteria culture tank. For example, in one embodiment of the membrane separation type activated sludge treatment apparatus shown in FIG. 1, the connecting pipe 7 or the connecting pipe 9 can be provided with an organic matter inflow control means. In the case where the connecting pipe 7 has an organic matter inflow control means, the biological reaction tank 8 and / or the biological reaction tank 10 can be used as a mycophagous bacteria culture tank. In order to use the biological reaction tank 8 and / or the biological reaction tank 10 as a mycophagous bacteria culture tank, the inflow of organic waste water is stopped by the organic matter inflow control means in the connecting pipe 7. Thereby, the new inflow of the organic waste water from the biological reaction tank 2 to the biological reaction tank 8 and / or the biological reaction tank 10 can be stopped. At this time, the bacteriophage bacteria are cultured by maintaining the inside of the bacteriophage bacteria culture tank in an aerobic condition. Further, in the embodiment of the membrane separation type activated sludge treatment apparatus shown in FIG. 1, when the connection pipe 9 has the organic matter inflow control means, the bioreaction layer 10 can be used as a mycophagous bacteria culture tank. In another embodiment, the biological reaction tanks 2, 8, 10 may be used as bacteriophage bacteria culture tanks by installing organic matter inflow control means in the inflow system of the wastewater that supplies organic wastewater. it can. The organic matter inflow control means is not particularly limited as long as it can stop further inflow of organic matter (that is, organic wastewater) into the fungal microbial culture tank, and adopts a known configuration such as a gate valve. Can do.

Moreover, the membrane separation type | formula activated sludge processing apparatus of this invention can also further be provided with a mycophactic bacteria culture tank as a different embodiment separately from a biological reaction tank. As one embodiment of such a membrane separation type activated sludge treatment apparatus, as shown in FIG. 3, the mycophagous bacteria culture tank 15 and at least one of the biological reaction tanks are connected by a connecting pipe 14. Then, surplus sludge generated in the biological reaction tank 8 is sent to the bacteriophage bacteria culture tank 15 via the connecting pipe 14. Here, the connecting pipe 14 is provided with an organic matter inflow control means, and further inflow of organic waste water or the like into the mycogenic bacteria culture tank 15 is restricted. The bacteriophage bacteria culture tank 15 has aeration means (air blower 4d and diffuser 5d), and the inside of the bacteriophage bacteria culture tank 15 is kept under aerobic conditions. The bacteriophage bacteria culture tank may be provided with a flow meter 6d for monitoring aerobic conditions. When excess sludge is sent to the mycophagous bacteria culture tank 15, the inflow of organic substances is restricted, and the mycophagous bacteria are cultured while maintaining aerobic conditions. By this culture, mycophagous bacteria grow and microbial cells and organic matter in the excess sludge are decomposed by the mycophagous bacteria. Here, the bacteriophage bacterium culture tank 15 is at least one of biological reaction tanks (for example, a biological reaction tank to which surplus sludge has been sent (the biological reaction tank 8 corresponds in the form of FIG. 3) or organic waste water. The sludge return means 16 for sending the activated sludge regenerated to the first biological reaction tank to which is supplied (in the form of FIG. 3 corresponds to the biological reaction tank 2). Via this sludge return means, the activated sludge regenerated in the mycological bacteria culture tank is sent to the biological reaction tank and repeatedly used for biological treatment.
In addition, the position where the mycobacterial bacterial culture tank 15 is connected is not particularly limited and is not limited to the following form, but as shown in FIG. 4 (a), the first biological reaction tank 8 to which organic waste water is supplied and You may connect and you may connect with the 2nd biological reaction tank 10 as shown in FIG.4 (b).

  In this specification, "membrane separation type activated sludge treatment equipment" is a kind of activated sludge process that purifies sewage and industrial wastewater, etc., and is a combination of treated water (treated water) and solid components (activated sludge). The separation is performed by using a microfiltration membrane or an ultrafiltration membrane instead of a conventional sedimentation basin. A method of treating wastewater using such an apparatus is called a membrane separation type activated sludge method. The membrane-separated activated sludge treatment apparatus to which the present invention can be applied can include a bacteriophage bacteria culture tank that regenerates surplus sludge into activated sludge when surplus activated sludge is generated in a biological treatment tank. Any device can be used as long as it can have a configuration in which the activated sludge regenerated thereby can be reused, and is not particularly limited. Each configuration of a biological treatment tank and a membrane separation unit, an air blower, an air diffuser, a pump, a flow meter and the like constituting a membrane separation type activated sludge apparatus to which the present invention can be applied, unless otherwise specified in the present specification. Usually used ones or known ones can be used.

  “Organic wastewater” refers to wastewater mainly composed of organic matter, such as sewage, factory wastewater, and restaurant wastewater.

The “biological reaction tank” refers to a tank for decomposing organic matter in organic wastewater using activated sludge. The MBR only needs to include at least one biological reaction layer, and may have a plurality of biological reaction tanks. The biological reaction tank can be equipped with an air blower, an air diffuser, a flow meter, etc. for keeping the inside of the tank in an aerobic condition, and can also be equipped with a membrane separation unit for separating activated sludge and treated water. it can.
Here, the sludge density | concentration in the reaction tank in biological treatment can be shown by "MLSS" (Mixed Liquor Suspended Solid (active sludge suspended matter)). “MLSS” refers to the sum of activated sludge and other suspended solids concentration (suspended solids component (SS component)). Mainly used as an indicator of activated sludge concentration, and the unit is mg / L.

  In addition, “COD” (Chemical Oxygen Demand) can be used as an index indicating the concentration of water-based organic components. “COD” indicates the amount of oxygen required to oxidize the amount of oxidizable substance in water, and mg / L is used as the unit. Further, “TOC” (Total Organic Carbon) can be used as an index indicating the concentration of the organic component related to water quality, and mg / L is used as a unit.

  Here, “activated sludge” is a general term for organic sludge mainly composed of thousands of aerobic microorganisms (bacteria, protozoa, etc.). Widely used in treatment plants and septic tanks. The activated sludge that can be used in the present invention is not particularly limited as long as it contains bacteriophage bacteria, and known activated sludge can be used. In addition, when necessary, bactericidal bacteria may be added to the activated sludge before being used for MBR. When adding bacteriophage bacteria to the activated sludge, for example, it can be added at a ratio of about 10 to 20% with respect to the amount of microorganisms in the activated sludge.

“Excess sludge” refers to the amount of sludge that is excessively increased when the microorganism concentration in the activated sludge is adjusted to a certain level in the biological treatment of organic wastewater such as the activated sludge process. Say. In MBR, operation is often performed while maintaining the activated sludge concentration (MLSS) at about 8,000 to 15,000 mg / L. Therefore, for example, when the activated sludge concentration in the MBR is set to MLSS = 8,000 to 15,000 mg / L, if the MLSS further increases, the surplus becomes surplus sludge.
More specifically, when MLSS in the bioreactor is in the range of 8,000 to 20,000 mg / L, when MLSS in the bioreactor is maintained at 8,000 to 15,000 mg / L In addition, it is preferable to transfer the activated sludge in the biological reaction tank as surplus sludge to the bacteriophage bacteria culture tank, and when the MLSS concentration falls within the range of 10,000 to 15,000 mg / L, the surplus sludge is transferred to the bacteriophage bacteria culture tank. More preferably, it is transferred.
However, since the concentration (MLSS value) of the activated sludge to be maintained differs depending on the wastewater type and the purpose of treatment, the criteria for determining surplus sludge also differ depending on the wastewater type and the purpose of treatment.

  As used herein, “mycophagous bacteria” refers to bacteria that can kill other microorganisms and consume the cells as nutrient sources. Examples of aerobic bacteriophage bacteria contained in organic wastewater include, but are not limited to, for example, bacteriophage bacteria belonging to the family Xanthomonadaceae, bacteriophage bacteria belonging to the family Bdellovibrionaceae, bacteriophage bacteria belonging to the order Myxococcales, Sphingobacteriia Mention may be made of the mycophagous bacteria belonging to the class Flavobacteriia, and the mycophagous bacteria belonging to the class Cytophagia.

Examples of the mycophagous bacteria belonging to the family Xanthomonadaceae include the genus Lysobacter, which is known to secrete degrading enzymes outside the cell and dissolve other bacteria. Other examples of mycophagous bacteria belonging to the family Xanthomonadaceae and related species include, but are not limited to, Luteimonas sp., Xanthomonas sp., Pseudoxanthomonas sp., And Thermomonas sp.
Examples of mycophagous bacteria belonging to the family Bdellovibrionaceae include Bdellovibrio bacteria. This bacterium is known to invade into the cells of other bacteria and prey on other bacteria from inside the cells. Other examples of mycophagous bacteria belonging to the family Bdellovibrionaceae and related species thereof include, but are not limited to, Vampirovibrio sp.
Examples of mycophagous bacteria belonging to the order Myxococcales include Myxcoccus bacteria, which are known to secrete degrading enzymes outside the cells and dissolve other bacteria. Other examples of mycophagous bacteria belonging to the order Myxococcales and related species include, but are not limited to, Sorangium cellulosum.
Examples of mycophagous bacteria belonging to the class Sphingobacteriia include Saprospira bacteria. Other examples of the phagocytic bacteria belonging to the class Shingobacteriia and related species thereof include, but are not limited to, Lewinella cohaerens, Aquiflexum sp., And Sphingobacterium sp.
Examples of bacteriophage bacteria belonging to the class Flavobacteriia include Flavobacterium bacteria. In addition, examples of mycophagous bacteria belonging to the Flavobacteriia class and related species thereof include, but are not limited to, Chryseobacterium, Imtechella halotolerans, Alkaliflexus sp., And Solidalea koreensis.
Examples of mycophagous bacteria belonging to the class Cytophagia include Cytophaga bacteria. Other examples of mycophagous bacteria belonging to the class Cytophagia and related species include, but are not limited to, Leadbetterella byssophila.

In the present specification, the “bacterial phagocytic culture tank” is a tank for regenerating surplus sludge into activated sludge by culturing bacteriophage bacteria in the surplus sludge. The surplus sludge is cultured in the “bacteriophagous bacterial culture tank” under “aerobic conditions” and “under no additional organic substances from the outside to the surplus sludge”. Under such conditions, for example, one or more species of mycophagous bacteria as listed above can be grown. Then, the bacteriophage bacteria grown in the bacteriophage bacteria culture tank decompose other microorganisms and other organic substances that have been killed or lysed in the excess sludge, thereby reducing the organic matter concentration in the excess sludge.
Here, “the condition that no organic matter is added from the outside to the surplus sludge” means that when surplus sludge is cultured in the bacteriophage bacteria culture tank, the extra sludge is contaminated with extra organic matter from the outside. Means no. Specifically, it means that there is no further inflow of organic waste water or activated sludge to the fungal phagocytic culturing tank being cultured. In order to satisfy such conditions, for example, in the membrane-separated activated sludge treatment apparatus, organic matter inflow control means for temporarily stopping the inflow of organic waste water or activated sludge to the mycological bacteria culture tank is used. do it.

There are no particular restrictions on the aerobic conditions in the bacteriophage bacterium culture tank as long as aerobic bacteriophage bacteria can grow during the culture. As the aerobic condition, for example, the dissolved oxygen amount (DO, unit mg / L) in the activated sludge can be adjusted to be 2.0 or more. That is, the bacteriophage bacteria culture tank is provided with aeration means for making the inside of the tank an aerobic condition. The aeration means is not limited as long as the aerobic condition is satisfied, and for example, a known air blower or a diffuser can be used.
Moreover, it is preferable to culture | cultivate the excess sludge in a bacteriophage bacteria culture tank for 7 to 14 days, and it is more preferable to culture for 10 to 14 days. The temperature for culturing excess sludge in the mycophagous bacterial culture tank is preferably within the range of 25 to 35 ° C, and more preferably within the range of 29 to 31 ° C. It is preferable that the pH when surplus sludge is cultivated in a mycophagous bacterial culture tank be around 6 to 9 neutral.

In addition, it is preferable to perform the culture | cultivation of the excess sludge in a bacteriophage bacteria culture tank until the value of MLSS reduces 20 to 80%, and it is more preferable to carry out until it reduces 50 to 80%. Here, in the membrane-separated activated sludge treatment apparatus (for example, in a biological treatment tank), in order to measure the amount of organic substances in the tank, a known automatic TOC measuring device or MLSS measuring device (for example, Iijima Electronics Co., Ltd.) It can be calculated as TOC, MLSS, and COD using IM-50P).
Further, the activated sludge whose volume has been reduced and regenerated in the bacteriophage bacteria culture tank can be returned to the biological reaction tank or the like by the sludge return pipe and reused. In addition, you may equip the sludge return pipe | tube which sends the surplus sludge to a bacteriophage bacteria layer, and the sludge return pipe | tube which sends the regenerated activated sludge to a biological treatment tank.

In the following test, a 3-tank, polycarbonate membrane separation activated sludge treatment apparatus (MBR: Membrane bioreactor) as shown in FIGS. 1 and 2 was used.
The capacity of each tank of MBR is 92L for the first tank, 80.5L for the second tank, and 57.5L for the three large tanks, respectively. As described above, the membrane separation activated sludge treatment apparatus used in this test is a pilot scale reactor having a total capacity of 230 L.
As the activated sludge, standard activated sludge distributed from Kinu Aqua Station of the West Basin Sewerage Office in Ibaraki Prefecture was used.

As waste water, organic artificial sewage was used. As the concentration of the organic substance, two types of (i) low concentration or (ii) high concentration are used, and the respective compositions are as shown below.
(I) Composition of artificial sewage with low concentration (COD: 450mg / L): CH3COONa (2.65g / L), NH4Cl (0.376g / L), KH2PO4 (0.109g / L), peptone (0.706g / L), FeCl3 ・ 6H2O (0.782g / L), CaCl2 (1.56mg / L), MgSO4 (1.56mg / L), KCl (1.56mg / L), and NaCl (1.56mg / L)
(Ii) Composition of artificial sewage with high concentration (COD: 900 mg / L): CH3COONa (5.30 g / L), NH4Cl (0.751 g / L), KH2PO4 (0.217 g / L), peptone (1.41 g / L) , FeCl3 ・ 6H2O (1.57mg / L), CaCl2 (3.13mg / L), MgSO4 (3.13mg / L), KCl (3.13mg / L), and NaCl (3.13mg / L)

An aeration blower was installed in each MBR tank, and the inside of the tank was adjusted to an aerobic environment by aeration during operation.
In the MBR, artificial sewage is introduced into the first tank from outside the system, and the artificial sewage flows in the order of the first tank, the second tank, and the third tank (membrane separation tank).
A membrane separation unit that separates the solid component and the liquid component is disposed in the membrane separation tank as the third tank. The membrane separation unit has four separation membranes. As the separation membrane, a flat and bag-shaped flat membrane made of PAN (polyacrylonitrile) of 150 mm × 300 mm (Awa Paper Co., Ltd., pore diameter 0.07 μm) is used. This separation membrane performs filtration by drawing water into the bag from outside the bag, and discharges the filtrate as purified water out of the system. The filtered activated sludge is returned to the first layer.
The inflow rate of artificial sewage into the system, the outflow rate of treated water out of the system, and the sludge return rate from the third tank to the first layer were all set to 115 L / day. This results in a hydraulic retention time (HRT) of 2 days.
In this example, the waste water treatment operation for a total of 19 days was performed using low-concentration artificial sewage in the first half (1-7 days) and high-concentration artificial sewage in the second half (8-19 days).
Regarding this example, measurement of the artificial sewage MLSS (Mixed Liquor Suspended Solid), temperature, pH, organic substance concentration in the treated water (TOC: Total Organic Carbon, COD: Chemical Oxygen Demand), etc. And observed changes in physicochemical parameters according to the driving conditions.
MLSS measurement was performed around 30 cm from the sludge interface using an MLSS measuring instrument (Iijima Electronics Co., Ltd., IM-50P). Moreover, each measurement of temperature and pH was performed in the vicinity of 30 cm from the sludge interface using a pH meter (HORIBA, D-55). The TOC value (Shimadzu Corporation, TOC-L) is used for the organic substance concentration in the treated water, and the COD value is a kit (Hach, TNT820 or TNT821) corresponding to the COD analyzer (Hach, DR2800 or DRB200). ).
Activated sludge at each time point was collected, and microbial flora analysis was performed using a next-generation sequencer (Illumina, MiSeq).
Here, the microbial flora analysis in the next-generation sequencer was performed according to the following procedure. First, a bead beater (biomedical) with zirconia / silica beads with an average particle size of 0.1 mm added to a sludge sample (centrifugal sediment) of standard activated sludge obtained by centrifugation. Crush the microorganism cells contained in the sludge sample. Next, chromosomal DNA is extracted and purified from the obtained cell lysate by a phenol / chloroform extraction method. Next, based on a universal primer targeting 16S rRNA of the chromosomal DNA, a reference document (J Gregory Caporaso et al., The ISME Journal (2012) 6, 1621-1624) to which a barcode sequence for illumina and the like was added. 16S rRNA gene was amplified by PCR (Polymerase Chain Reaction) method using the primers described in the supplementary information.
Using the AMPure magnetic beads (Beckmann coulter, A63881) and the purification magnetic stand (Beckmann coulter, A32782), unreacted primers and primer dimers were removed from the obtained PCR amplification product, and then obtained. The purified product was fractionated by agarose gel electrophoresis, and only the PCR amplification product having the desired fragment length was purified using a spin column (Promega, Wizard SV Gel and PCR Clean-up System). Next, the DNA concentration in the PCR amplification product sample was quantified using a fluorescent reagent kit for DNA staining Quant-iT PicoGreen dsDNA Assay Kit (manufactured by Thermo scientific, P11496) and a fluorescence spectrometer for trace amounts (manufactured by Thermo scientific, NanoDrop 3300). Based on the measured DNA concentration, the necessary amount from the PCR amplification product sample was subjected to MiSeq Reagent Kits v2 (manufactured by Illumina, MS-102-2003), and DNA sequence analysis was performed using the next-generation sequencer.
As a result of analysis by a next-generation sequencer, sequence data of about 10,000 to 100,000 reads / sample was obtained. For the obtained sequence data, linkage of gene sequence information using software ea-utils-1.1.2-301 (available from https://code.google.com/p/ea-utils/downloads/list) Furthermore, after removing the chimeric sequence using the software Mothur version 1.31.2, phylogenetic analysis of the gene sequence was performed using the software QIIME version 1.6.0, and the relative abundance of each microbial species was increased and decreased. The relationship with physicochemical parameters (increase / decrease in MLSS) was considered. For details of the software Mothur version 1.31.2, reference literature (Schloss P. D et al., Appl. Environ. Microbiol (2009) 75, 7537-7541.) Can be referred to, and the software QIIME version 1.6.0. For more details, reference literature (Caporaso J. G et al., Nat. Methods (2010) 7, 335-336.) Can be referred to.

Figure 5 shows the results of a 19-day wastewater treatment operation using low-concentration artificial sewage in the first half (1-7 days) and high-concentration artificial sewage in the second half (8-19 days). Indicates. FIG. 5A shows the change in MLSS during the operation period. FIG. 5 (b) shows the fold change of the top 10 bacteria having the highest increase rate when comparing the relative abundance on the 5th day and 19th day in the microbial flora analysis. Also, the table of FIG. 5 (c) describes the phylogenetic information of those 10 types.
As shown to Fig.5 (a), MLSS increased rapidly by making inflow artificial sewage into a high density | concentration from a low density | concentration (8-12 days). This increase in MLSS is thought to have proliferated rapidly by assimilating organic matter contained in artificial sewage by many microorganisms in activated sludge. However, after the 15th day, despite the presence of high-concentration organic matter, MLSS decreased gradually, indicating that the amount of microorganisms (solid content) contained in the activated sludge decreased.
In order to discuss this result, microbial community flora analysis during the operation period revealed that there were bacteriophage bacteria as resident bacteria in the activated sludge. Furthermore, it was found that among these mybivorous bacteria, Luteimonas marina, Fusibacter sp., Luteimonas aestuarii, Proteocatella sphenisci, Luteimonas sp., And Pseudoxanthomonas sp. That is, it was suggested that the mycophagous bacteria prey on and decompose other bacteria and their dead cells, contributing to the reduction of the amount of microorganisms in the activated sludge.

(Example 2)
In this example, a low concentration artificial sewage is used in the first half (1st to 21st day) and a high concentration artificial sewage is used in the second half (22th to 30th day). went. The conditions other than the period using the low-concentration or high-concentration artificial sewage and the total operation treatment period were all performed in the same manner as in Example 1. In addition, MLSS measurement and microbial community flora analysis were performed in the same manner as in Example 1. During the operation period, the tank was kept in an aerobic environment by aeration constantly.
The result is shown in FIG. FIG. 6A shows a change in MLSS during the operation period. FIG. 6 (b) is a graph showing the change in the magnification of the top 10 types with the highest increase rate compared with the relative abundance on the 19th and 30th day of operation. It is a table | surface which shows those 10 types of phylogenetic information.
MLSS increased rapidly by increasing the concentration of inflow artificial sewage (22-26 days). Like Example 1, it is thought that many microorganisms in activated sludge proliferated rapidly by assimilating the organic substance contained in artificial sewage. In addition, MLSS decreased gradually after the 26th day, and it was shown that the amount of microorganisms (solid content) contained in activated sludge decreased.
As a result of microbial community flora analysis during this operation period, Bdellovibrio sp., Leadbetterella byssophila, Luteimonas marina, Psedoxanthomonas sp., And Aquiflexum sp. It was suggested that the predation and decomposition of other bacteria and their dead cells contributed to the reduction of the amount of microorganisms in the activated sludge.

(Example 3)
In an actual sludge treatment apparatus, the amount of organic matter in the biological reaction tank that performs biological treatment increases as the operation continues, and surplus sludge is generated. In particular, in MBR, activated sludge and surplus sludge are not discharged out of the system from the biological reaction tank, so that the organic matter concentration of surplus sludge is higher than that of a general sludge treatment apparatus. In order to confirm whether the excess sludge can be reduced by restricting the amount of inflowing organic matter with respect to such excess sludge with a high organic matter, the following test was performed.
In this example, wastewater treatment operation was performed for a total of 21 days using high-concentration artificial sewage in the first half (1st to 4th day) and low-concentration artificial sewage in the second half (5th to 21st day). The conditions other than the period using the low-concentration or high-concentration artificial sewage and the total operation treatment period were all performed in the same manner as in Example 1. In addition, MLSS measurement and microbial community flora analysis were performed in the same manner as in Example 1. During the operation period, the tank was kept in an aerobic environment by aeration constantly.
The results are shown in FIG. 7A shows the change in MLSS during the operation period, and FIG. 7B compares the relative abundances on the 5th and 10th days of operation, and the top 10 with the highest increase rate. A graph of species fold change is shown, and FIG. 7 (c) describes phylogenetic information of the top 10 species in increasing magnification.
As shown to Fig.7 (a), MLSS decreased sharply by changing inflow artificial sewage from high concentration to low concentration (5-21 days). Since MLSS detects solid components in activated sludge, for example, cells whose growth has been weakened, dead cells, cell debris, etc. are counted as MLSS values. Therefore, it is considered that such a rapid decrease in MLSS indicates that microbial cells have been killed, crushed, and dissolved, and that the residue and the bacterial bodies themselves have been decomposed by other bacteriophage bacteria.
As a result of the analysis of the microbial flora during this operation period, the mycophagous bacteria Luteimonas sp., Thermomonas sp., And Luteimonas marina grew rapidly during the period when the amount of microorganisms decreased, and the mycophagous bacteria became other bacteria. It was thought that the dead cells were preyed and decomposed.

DESCRIPTION OF SYMBOLS 1 Membrane separation type activated sludge processing apparatus 2, 8, 10 Biological reaction tank 3 Pump 4 Air blower 5 Aeration pipe 6 Flow meter 7, 9, 14 Connection pipe 11 Membrane separation unit 12 Transmembrane pressure gauge 13, 16 Sludge return pipe 15 Bacteriophage bacteria culture tank

Claims (9)

A biological reaction tank for biological treatment of organic wastewater;
A membrane separation unit for separating the organic wastewater purified in the biological reaction tank into purified water and activated sludge;
A bacteriophage bacteria culture tank for regenerating surplus sludge generated in the biological reaction tank into activated sludge, comprising aeration means for culturing bacteriophage bacteria under aerobic conditions; ,
A membrane-separated activated sludge treatment apparatus comprising sludge return means for sending activated sludge regenerated in the bacteriophage bacteria culture tank to the biological reaction tank,
By culturing the bacteriophage bacteria in the excess sludge in the bacteriophage bacteria culture tank, the excess sludge is regenerated into activated sludge, and the regenerated activated sludge is repeatedly used in the biological reaction tank. Membrane separation type activated sludge treatment equipment.   The apparatus according to claim 1, further comprising organic matter inflow control means for controlling inflow of organic matter with respect to the bacteriophage bacterium culture tank.   The apparatus of Claim 1 or 2 with which the said bacteriophage bacteria culture tank is further equipped with the means to measure the amount of organic substances.   The bacteriophage bacterium belongs to the family Xanthomonadaceae, the bacteriophage bacterium belonging to the family Bdellovibrionaceae, the mycophagous bacterium belonging to the order Myxococcales, the bacteriophage bacterium belonging to the class Sphingobacteriia, the phagocytic bacterium belonging to the class Flavobacteriia, and the Cytophagia class Device according to any one of claims 1 to 3, characterized in that it is at least one bacterium selected from the group of mycophagous bacteria belonging to the group.   The apparatus according to any one of claims 1 to 4, wherein culture of the bacteriophage bacteria in the bacteriophage bacteria culture tank is performed for at least 7 days. A method of regenerating surplus sludge generated in the membrane separation type activated sludge method into activated sludge,
A method comprising culturing surplus sludge under aerobic conditions and under the condition that no organic matter is added from the outside to the surplus sludge,
A regeneration method comprising culturing bacteriophage bacteria in surplus sludge by the culture and decomposing organic matter in the surplus sludge by the bacteriophage bacteria.   7. The regeneration method according to claim 6, wherein the bacteriophage bacteria cultivated by the culturing step are fungiphagous bacteria belonging to the family Xanthomonadaceae, bacteriophage bacteria belonging to the family Bdellovibrionaceae, bacteriophage bacteria belonging to the order Myxococcales, Sphingobacteriia A regeneration method, characterized in that it is at least one bacterium selected from the group of mycophagous bacteria belonging to the genus, Mycophagous bacteria belonging to the Flavobacteriia class, and Mycophagous bacteria belonging to the Cytophagia class.   The regeneration method according to claim 6 or 7, wherein the culturing step is performed for at least 7 days. A membrane-separated activated sludge method comprising a step of biologically treating organic wastewater using the activated sludge regenerated by the regeneration method according to any one of claims 6 to 8.

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