JP2005066381A - Method and apparatus for treating organic waste water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for treating organic waste water, in which sewage, excreta or the organic waste discharged from a manufacturing process of a food factory, a chemical factory or the like is treated by biological digestion, wherein the amount of the waste sludge to be discharged to the outside can be reduced and the nitrogen-containing organic or inorganic content of the treated water to be discharged to the outside can be made small. <P>SOLUTION: In this method for biologically treating the organic waste water, the sludge generated in nitrification/denitrification processing can be made soluble after the organic waste water is subjected to nitrification/denitrification processing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for treating organic wastewater containing organic substances, for example, organic wastewater discharged from manufacturing processes such as sewage, human waste, food factories, and chemical factories by biological digestion.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, as a method of treating this type of organic wastewater, organic components of organic sludge are obtained by aerobic or anaerobic microbial decomposition such as an aerobic digestion method called an activated sludge method or an anaerobic methane digestion method. Biological digestion is used. In this method, organic matter is used as a gas component such as carbon dioxide and methane gas, and microbial biomass produced by biological digestion and treated sludge containing surplus sludge consisting of untreated residual sludge are solid-liquid separated in a sedimentation tank or the like. The surplus sludge is usually processed by offshore speculation or land reclamation.
[0003]
However, since dumping into the ocean will lead to environmental destruction, it is almost forbidden in recent years when the protection of the global environment is being screamed. In land reclamation, it is becoming more difficult to secure landfill sites each year.
[0004]
Therefore, the present applicant has filed a patent application as an invention described in Japanese Patent Application Laid-Open No. 9-10791 as a method capable of reducing the amount of excess sludge generated by biological treatment of organic wastewater.
In the present invention, an organic waste liquid sent from an organic waste liquid storage device is subjected to an aerobic biological treatment in an aeration device, and then this treatment liquid is solid-liquid separated into treated water and sludge by a solid-liquid separation device. Part of the sludge separated by the separation device is returned to the aeration device. Of the sludge separated by the solid-liquid separation device, the excess sludge is heat-exchanged by a heat exchanger and then solubilized at a high temperature by a solubilizer. In this method, the solubilized processing liquid is returned to the aeration apparatus.
[0005]
However, since sludge generated by biological treatment generally contains proteins, nitrogen compounds such as ammonia in the liquid returned from the solubilizer to the aeration device are combined with the treated water discharged from the solid-liquid separator. There is a problem of being released to the outside. In addition, since sludge generated by biological treatment generally contains a phosphorus component, the phosphorus compound in the liquid returned from the solubilizer to the aeration device is discharged to the outside together with the treated water discharged from the solid-liquid separator. There is a problem of being released.
[0006]
The present invention has been made to solve such problems, and can significantly reduce the amount of excess sludge discharged outside the treatment system, and can also treat the treated water discharged outside the treatment system. It is an object of the present invention to provide an organic wastewater treatment method and apparatus for reducing nitrogenous organic content or nitrogenous inorganic content.
Another object is to provide an organic wastewater treatment method and an apparatus for reducing the amount of phosphorus component in the treated water released outside the treatment system.
[0007]
[Means for Solving the Problems]
In order to solve such problems, the present invention was made as a method and apparatus for treating organic wastewater, and the feature as a method for treating organic wastewater is to biologically treat organic wastewater. The method is to solubilize sludge generated by nitrification and denitrification after nitrification and denitrification of organic wastewater.
[0008]
Another feature of the organic wastewater treatment equipment is the biological treatment of organic wastewater, a means for nitrifying and denitrifying organic wastewater, and solubilizing sludge generated by nitrification and denitrification. A solubilization tank is provided.
Therefore, it is possible to reduce the amount of nitrogen contained in the treated water released to the outside of the treatment system by the sludge solubilization effect as described above and the nitrification and denitrification treatment as described above. It becomes.
[0009]
The nitrification and denitrification treatment of organic wastewater is performed batchwise in a reaction tank, for example.
The nitrification process in this case is performed by aeration, for example, and the denitrification process is performed by stopping the aeration. The solubilization treatment solution is returned to the reaction vessel preferably 3 hours to 30 minutes before aeration is stopped, and more preferably 1 hour to 30 minutes.
[0010]
Further, other aspects of nitrification and denitrification treatment of organic waste water are performed by an anaerobic treatment process, a primary aeration process, a denitrification process in an oxygen-free tank, and a secondary aeration process. In this case, the sludge solid-liquid separated after the secondary aeration process is solubilized.
[0011]
Furthermore, other aspects of organic wastewater nitrification and denitrification treatment are performed by a denitrification process in an oxygen-free tank, an anaerobic treatment process, a treatment process in a compatible tank, a denitrification process in an oxygen-free tank, and an aeration process. The In this case, the sludge solid-liquid separated after the aeration process is solubilized. Nitrification is performed in the aeration process, and the nitrification liquid after nitrification is returned to the denitrification process.
[0012]
Furthermore, other aspects of nitrification and denitrification treatment of organic wastewater are performed by an anaerobic treatment step, a denitrification step in an oxygen-free tank, and an aeration step, and reduce dissolved oxygen in the treatment liquid after the solubilization treatment. Is made by Also in this case, nitrification is performed in the aeration process. The nitrification liquid after nitrification will be returned to the denitrification process.
[0013]
Furthermore, other aspects of nitrification and denitrification treatment of organic wastewater are performed by an anaerobic treatment process, a denitrification process in an oxygen-free tank, and an aeration process.
It is also possible to provide means for removing phosphorus in sludge generated by nitrification and denitrification.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
As shown in FIG. 1, the organic wastewater treatment apparatus of the present embodiment includes a reaction tank 1 and a solubilization tank 2. In the reaction tank 1, organic wastewater is treated batchwise. In this embodiment, sewage is used as the organic waste water that is raw water.
[0015]
In the present embodiment, processing is performed with raw water inflow, reaction, sedimentation, drainage, waste mud, etc. as one cycle. More specifically, as shown in FIG. 2, the steps of aeration, agitation, aeration, agitation, aeration, precipitation due to aeration stop, solid-liquid separation, and solubilization process are circulated while receiving the inflow of raw water. become. In this case, aeration is an aerobic process and agitation is an anaerobic process. The repeated steps of aeration and stirring, precipitation, and solid-liquid separation are performed in the reaction tank 1, and the solubilization process is performed in the solubilization tank 2. It is possible to adjust the processing time of each process so that the batch processing of the wastewater treatment from the inflow acceptance of the raw water to the discharge of the treated water is performed a plurality of times (for example, 2 to 4 times) per day. Depending on the properties, amount, etc., the processing time of each step may be adjusted so that batch processing is performed about once a day or about twice every three days.
[0016]
In the present embodiment, nitrification treatment is performed with nitrifying bacteria in the aeration process, and denitrification treatment with denitrifying bacteria is performed in the stirring process in which aeration is stopped. Thereafter, the sludge settles and is separated by stopping the aeration. The supernatant is discharged, etc., and a part of the settled sludge is held in the reaction tank 1 for the next batch process, and the remaining part of the sludge is supplied to the solubilization tank 2 and solubilized. As shown in FIG. 2, the solution solubilized in the solubilization tank 2 is preferably returned to the first step of stirring. In the nitrification step, in order to maintain the nitrification reaction by nitrifying bacteria, the pH is preferably 7 or more, and particularly preferably pH 7.0 to 8.0. The temperature is preferably 15 ° C to 35 ° C, more preferably 25 ° C to 35 ° C.
[0017]
The solubilized solution is returned to the reaction tank 1 3 to 30 minutes before stopping the first-stage aeration, preferably 1 hour to 30 minutes. The number of cycles is determined by the BOD-SS load of the reaction vessel. In general, in the case of high-load operation (BOD-SS load: 0.2 to 0.4 kg BOD / kgSS · day), it is preferable that the aeration and stirring nitrification denitrification treatment cycles be operated in 3 to 4 cycles. In the case of low load operation (BOD-SS load: 0.03 to 0.05 kgBOD / kgSS · day), it is preferable that the nitrification denitrification treatment cycle is operated in 2 to 3 cycles.
[0018]
The solubilization tank 2 is for solubilizing the sludge supplied from the reaction tank 1 as described above, and this solubilization is performed by a solubilizing enzyme such as protease. This solubilizing enzyme is produced by a thermophilic bacterium such as an aerobic thermophilic bacterium such as a Bacillus bacterium. Such thermophilic bacteria may be preliminarily held in the solubilization tank 2, previously contained in the sludge supplied to the solubilization tank 2, or newly added in the solubilization tank 2.
[0019]
Examples of Bacillus bacteria include Bacillus stearothermophilus (Bacillus stearothermophilus), Bacillus thermoreobolans (Bacillus thermoleovorans) Etc., especially Bacillus(Bacillus)SPT2-1 [FERM P-15395], Bacillus(Bacillus)SPT3 [FERM P-19226], Geobacillus(Geobacillus) SPT4 [FERM BP-0842], Geobacillus(Geobacillus) SPT5 [FERM BP-08453 ],Geobacillus(Geobacillus) SPT6 [FERM BP-08454], Geobacillus(Geobacillus) SIt is preferable to use PT7 [FERM BP-08455] or the like.
In the solubilization tank 2, sludge is decomposed by thermophilic bacteria in this way, but ozonolysis, electrolysis, thermal alkali decomposition, enzymatic decomposition (for example, protease, lipase, glycosidase, etc. are added alone or in combination), etc. The present invention may be implemented in combination with various conventionally known methods.
[0020]
In the solubilization tank 2, organic sludge is solubilized anaerobically or aerobically under high temperature conditions. In this case, the anaerobic or aerobic microorganism inoculated cells (thermophilic bacteria) used under high temperature conditions are obtained, for example, by culturing microorganisms from a conventional anaerobic or aerobic digester. In addition, the optimum temperature of the solubilization tank 2 is preferably operated in a temperature range of 50 to 90 ° C., but it is a thermophilic that decomposes organic solids contained in the sludge that is the high-temperature treatment target. For example, in the case of thermophilic bacteria isolated from sewage surplus sludge, both the solubilization reaction by microorganisms (thermophilic bacteria) and the physicochemical thermal decomposition by heat are efficiently performed simultaneously. The temperature under high temperature conditions is in the range of 55 to 75 ° C., preferably 60 to 70 ° C., so that it can occur sufficiently.
[0021]
In any case, depending on the type of microorganism, a temperature of 50 to 90 ° C. may be used so that both the solubilization reaction by the microorganism (thermophilic bacterium) and the physicochemical thermal decomposition by heat can occur efficiently and sufficiently. It is desirable to set the temperature range. In particular, in the case of using an aerobic thermophilic bacterium belonging to the genus Bacillus, it is preferably set to a temperature range of 55 to 70 ° C, and more preferably 60 to 65 ° C. Moreover, when using the aerobic thermophilic bacterium of the genus Geobacillus, it is preferable to set the temperature range of 55 to 65 ° C.
[0022]
Moreover, pH is set so that it may become the range of pH 6-9, Preferably it is the range of 7-8 according to the kind of microorganisms. This is to prevent the solubilization treatment liquid from adversely affecting the nitrification or denitrification treatment. Further, the solubilization treatment is preferably an aerobic treatment in order to decompose (nitrify) ammonia produced by the sludge decomposition to some extent.
[0023]
In the present embodiment, the solubilized sludge is returned to the reaction tank in the first (first) aeration process step 3 hours to 30 minutes before stopping the aeration process, preferably 1 hour to 30 minutes before. The Thereby, the organic matter contained in the solubilized sludge can be effectively used as a proton source (BOD source) in the denitrification treatment, and denitrification can be promoted. Therefore, since the amount of chemicals such as methanol generally used as a proton source can be reduced, the cost associated with the amount of chemicals can be reduced.
In this case, the solubilization time is preferably 12 to 72 hours, more preferably 18 to 48 hours, and most preferably 20 to 36 hours. The solubilization treatment time is set by a combination method of a wastewater treatment system for performing nitrification and denitrification treatment of wastewater and sludge solubilization, and will be described later for each embodiment.
[0024]
In addition, ammonia is generated by solubilization of sludge by thermophilic bacteria, but ammonia contained in solubilized sludge is oxidized to nitrite nitrogen and nitrate nitrogen that can be denitrified in the aeration process. Become. As a result, the denitrification process is suitably performed, and no harmful nitrogen component is released outside the system.
In the present embodiment, it is important to oxidize ammonia to nitrous acid or nitric acid while leaving the organic matter in the aeration step, so the timing at which the solubilized sludge is returned to the reaction tank in the first aeration treatment step. And the setting of the solubilization processing time is important.
[0025]
(Embodiment 2)
This embodiment is a batch-type treatment method as in the first embodiment, in which the treatment apparatus is composed of the reaction tank 1 and the solubilization tank 2, and aeration, stirring, It is the same as in the first embodiment in that the steps of aeration, stirring, aeration, precipitation due to aeration stop, solid-liquid separation, and solubilization process are circulated. Therefore, also in the present embodiment, nitrification treatment by nitrifying bacteria is performed in the aeration step, and denitrification processing by denitrifying bacteria is performed in the stirring step in which aeration is stopped.
[0026]
However, in this embodiment, as shown in FIG. 3, the treatment liquid after the solubilization treatment is returned to the first (first) stirring step, and in this respect, is returned to the aeration step. Is different.
[0027]
Also in the present embodiment, since the solubilization treatment liquid is returned to the reaction tank 1 in the denitrification process, the organic matter contained in the solubilization treatment liquid is effectively used as a proton source in the denitrification treatment, and denitrification is promoted. Is done. In this case, in order to reduce ammonia contained in the solubilized sludge, it is preferable to oxidize to nitrite nitrogen and nitrate nitrogen that can be denitrified in the solubilization treatment. Specifically, the solubilization treatment time is implemented. It is conceivable that the length is longer than that of Form 1, and is preferably 24 to 72 hours, more preferably 36 to 72 hours.
[0028]
In particular, in this embodiment, since the organic substance as a proton source is directly returned to the denitrification process, the amount of chemicals such as methanol that is generally used can be reduced, and the cost associated with the amount of chemicals is reduced. There is an effect that can be done. As described above, by combining sludge solubilization treatment with nitrification and denitrification treatment of wastewater, and by optimally setting the conditions of each treatment step when combined, the amount of excess sludge generation can be greatly reduced In addition, there is an effect that the quality of the treated water can be maintained well.
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially various Bacillus disclosed in Embodiment 1 (Bacillus) Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set so as to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
In addition, the temperature, pH, etc. of the nitrification step are the same as in the first embodiment.
[0029]
(Embodiment 3)
As shown in FIG. 4, the organic wastewater treatment apparatus of this embodiment includes a fermentation liquid storage tank 3, an anaerobic tank 4, a primary aeration tank 5, an oxygen-free tank 6, a secondary aeration tank 7, a precipitation tank 8, and A solubilization tank 2 is provided. As the liquid to be treated stored in the fermented liquid storage tank 3, an acid fermented liquid obtained by gas decomposition (methane fermentation) of fermented rice discharged from a food factory or the like and fermented is used in the present embodiment. Separately from the liquid to be treated, sewage or the like is supplied to the anaerobic tank.
[0030]
The anaerobic tank 4 anaerobically digests the sewage and the acid fermentation liquid supplied from the fermentation liquid storage tank 1, and if phosphorus is contained in the returned sludge or the sludge in the acid fermentation liquid, It has a function of releasing phosphorus into the liquid.
[0031]
The primary aeration tank 5 is used to aerobically biotreat the treatment liquid that has been anaerobically treated in the anaerobic tank 4 by aeration and agitation, to oxidize and decompose organic matter in the anaerobic treated water, or to nitrify inflowing ammonia. belongs to. The primary aeration tank 5 only needs to be provided with an aeration means, and the aeration means is not questioned, but an aeration tube or the like can be used, for example. The aeration treatment is preferably performed at room temperature with an air flow rate of 0.1 to 0.5 vvm so that aerobic digestion degradation is allowed. May be processed. The liquid to be treated is preferably adjusted to pH 5.0 to 8.0, more preferably pH 7.0 to 8.0.
[0032]
The anaerobic tank 6 is for denitrifying the treatment liquid that has been aerobically treated in the primary aeration tank 5.
The secondary aeration tank 7 is for aerobically biologically treating the treatment liquid denitrified in the oxygen-free tank 6. The secondary aeration tank 7 is configured in the same manner as the primary aeration tank 3, and biological treatment is similarly performed by aeration and agitation. The secondary aeration tank 7 in this case has functions of both nitrification and BOD removal. A part of the nitrification liquid that is the treatment liquid in the secondary aeration tank 7 is returned to the anoxic tank 6 (not shown), and nitric acid or nitrous acid in the nitrification liquid is denitrified.
[0033]
The sedimentation tank 8 is for solid-liquid separation of the treatment liquid biologically treated in the secondary aeration tank 7. The separated liquid is reused or discharged as the treatment liquid, and separated and precipitated solid content. A part of the sludge is supplied to the next solubilization tank 2 and the remaining part is returned to the anaerobic tank 4.
[0034]
Next, an embodiment of a processing method for processing both sewage and leftover food discharged from a food factory or the like by the processing apparatus having the above-described configuration will be described.
[0035]
First, the leftover food discharged from a food factory or the like is decomposed by gas. This gas decomposition is performed by, for example, acid fermentation and methane fermentation. An acid fermentation broth is obtained by such gas decomposition, and the acid fermentation broth is stored in the fermentation broth 3. The acid fermentation liquid is supplied from the fermentation liquid storage tank 3 to the anaerobic tank 4. Sewage is also supplied to the anaerobic tank 4.
[0036]
Then, the treated water after the anaerobic treatment is supplied to the primary aeration tank 5 in the next step and is aerobically treated while being aerated and stirred. The nitrification treatment is performed by the aerobic treatment by aeration and stirring.
Next, the treatment liquid aerated in the primary aeration tank 5 is supplied to the oxygen-free tank 6. In this oxygen-free tank 6, a denitrification process is performed.
Further, the acid fermentation liquid is supplied from the fermentation liquid storage tank 3 to the anoxic tank 6. This is because the acid fermentation broth is effectively used as a proton source (BOD source) during denitrification and promotes denitrification.
[0037]
The treatment liquid denitrified in the anaerobic tank 6 is supplied to the secondary aeration tank 7 and aerobically processed while being aerated and stirred. Nitrification is performed by the aeration process in the secondary aeration tank 7, and the BOD is removed.
Next, the treatment liquid aerated in the secondary aeration tank 7 is supplied to the precipitation tank 8. In this settling tank 8, solid-liquid separation is performed, and the separated liquid is reused or discharged as a treatment liquid, and a part of the sludge, which is separated and precipitated solid, is supplied to the solubilization tank 2 and is preferably used. Sludge is solubilized aerobically by heat bacteria.
Further, the remaining part of the precipitated sludge is returned to the anaerobic tank 4 as return sludge.
[0038]
The sludge solubilized in the solubilization tank 2 is returned to the oxygen-free tank 6 and processed again. Then, the denitrification process in the oxygen-free tank 6, the aeration process in the secondary aeration tank 7, the solid-liquid separation in the sedimentation tank 8, and the solubilization process in the solubilization tank 2 are repeated and repeated.
[0039]
In this embodiment, the sludge is solubilized not continuously as in the first embodiment, but in a continuous manner. When the sludge is solubilized in this manner, the amount of influent and the reaction tank An HRT is determined based on the effective capacity. That is, HRT can be calculated based on the equation of HRT (hydraulic residence time) = V / Q (V: reaction tank capacity, Q: influent amount).
It goes without saying that the volume of the reaction vessel can be reduced as the HRT is shortened as long as the desired solubilization is achieved. Therefore, by determining the solubilization time based on the HRT, redundant solubilization processing is avoided.
[0040]
The HRT is preferably selected based on the HRT that maximizes the production and secretion of thermophilic bacteria. If HRT is set in this way, the reaction by the produced and secreted sludge solubilizing enzyme can be used efficiently. Usually, the HRT is preferably set to 12 to 72 hours, more preferably set to 24 to 72 hours from the viewpoint of oxidizing ammonia in the solubilized solution, and the solubilizer is made compact and the quality of the treated water is improved. From the viewpoint of maintaining both, it is most preferable to set to 36 to 48 hours.
[0041]
Moreover, HRT of tanks other than the solubilization tank 2 is 0.5 to 1.5 hours in the anaerobic tank 4, 2 to 6 hours in the primary aeration tank 5, 0.5 to 3 hours in the anaerobic tank 6, and secondary. 0.5 to 2 hours in the aeration tank 7, preferably 0.5 to 1 hour in the anaerobic tank 4, 3 to 5 hours in the primary first aeration tank 5, 1 to 2 hours in the oxygen-free tank 6, and the secondary aeration tank 7 0.5 to 1.5 hours are preferable.
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially the various Bacillus disclosed in Embodiment 1( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set so as to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
In addition, the temperature, pH, etc. of the nitrification step are the same as in the first embodiment.
[0042]
(Embodiment 4)
In this embodiment, as shown in FIG. 5, a concentrator 9 is provided between the precipitation tank 8 and the solubilization tank 2, that is, in the flow path from the precipitation tank 8 to the solubilization tank 2.
[0043]
In the present embodiment, the sludge separated in the settling tank 8 is supplied to the concentrator 9. In the concentrator 9, sludge is concentrated by gravity sedimentation, for example. As the concentration method, in addition to gravity sedimentation, flotation concentration, evaporation concentration, membrane concentration, flocculant addition, drum screen type concentration, or a concentration method using centrifugal force can also be employed. The concentration rate of sludge is preferably concentrated to a moisture content of 99% by weight or less (sludge concentration of 1% by weight or more) from the viewpoint of improving the sludge solubilization rate by thermophilic bacteria and making the solubilization tank compact. The concentrated liquid after concentration is supplied to the solubilization tank 2. However, the sludge concentration preferably does not exceed 5% by weight. This is because if it exceeds 5% by weight, it is difficult to feed with a pump, and sludge foaming due to aerobic treatment in a solubilization tank becomes remarkable.
[0044]
Anaerobic treatment in the anaerobic tank 4, aeration treatment in the primary aeration tank 5, denitrification treatment in the anaerobic tank 6, aeration treatment in the secondary aeration tank 7, solid-liquid separation in the precipitation tank 8, solubilization tank 2 Since the solubilization process in is the same as that of the third embodiment, the description thereof is omitted.
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially the various Bacillus disclosed in Embodiment 1( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set so as to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0045]
(Embodiment 5)
In the present embodiment, as shown in FIG. 6, a nitrification tank 10 is provided between the solubilization tank 2 and the oxygen-free tank 6, that is, in a return flow path from the solubilization tank 2 to the oxygen-free tank 6. By providing such a nitrification tank 10, the ammonia contained in the sludge solubilizing solution changes to nitrous acid or nitric acid.
In the present embodiment, a part of the sludge is returned from the sedimentation tank 8 to the anaerobic tank 4, and the remaining sludge is also supplied to the nitrification tank 10 via the solubilization tank 2.
[0046]
The HRT of the solubilization tank in this embodiment is preferably selected based on the HRT that maximizes the production and secretion amount of the sludge solubilizing enzyme secreted by thermophilic bacteria. If HRT is set in this way, the reaction by the produced and secreted sludge solubilizing enzyme can be used efficiently. Usually, the HRT is set to 12 to 72 hours. In this embodiment, since the nitrification tank 10 is located after the solubilization tank, the solubilization treatment liquid is put into the nitrification tank 10 with ammonia remaining in the solubilization treatment liquid. In consideration of this, the HRT is more preferably set to 18 to 48 hours, and most preferably set to 20 to 36 hours.
[0047]
The operating conditions of the nitrification tank 10 are preferably 25 to 35 ° C. and the pH is preferably in the range of 7.0 to 8.0. The HRT of the nitrification tank 10 needs to oxidize the ammonia contained in the sludge solubilizing solution to nitrous acid or nitric acid, and to leave the organic matter as a proton source for the denitrification process in the next step. In view of the above, it is preferably 30 minutes to 3 hours.
Anaerobic treatment in the anaerobic tank 4, aeration treatment in the primary aeration tank 5, denitrification treatment in the anaerobic tank 6, aeration treatment in the secondary aeration tank 7, solid-liquid separation in the precipitation tank 8, solubilization tank 2 Since the solubilization process in is the same as that of the third embodiment, the description thereof is omitted.
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially various Bacillus disclosed in Embodiment 1 (Bacillus) Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set so as to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0048]
(Embodiment 6)
In this embodiment, two oxygen-free tanks are provided, and only one aeration tank is provided. This is different from the above-described third to fifth embodiments.
That is, as shown in FIG. 7, the biological treatment apparatus of the present embodiment includes a pre-anoxic tank 11, an anaerobic tank 4, a compatible tank 12, an oxygen-free tank 6, an aeration tank 13, a precipitation tank 8, a concentrator 9, and A solubilization tank 2 is provided.
[0049]
In this embodiment, the raw water that has flowed into the anaerobic tank 4 is supplied to the compatible tank 12.
The compatibility tank 12 has a function of changing the return path of the sludge and treatment liquid (nitrification liquid) from the aeration tank 13 depending on the degree of denitrification of the inflowing sewage. For example, when the degree of denitrification is high in summer, etc., it is used as an anaerobic tank to promote the phosphorus release reaction of the returned sludge in anaerobic conditions. By utilizing this, the denitrification reaction of the nitrification solution returned from the raw water and the aeration tank 13 to the pre-anoxic tank 11 or the compatible tank 12 is promoted.
[0050]
After the treatment in the compatible tank 12 is performed in this way, the raw water is supplied to the anoxic tank 6 and denitrified, and further supplied to the aeration tank 13 to be aerobically biologically treated by aeration and stirring. Next, it is supplied from the aeration tank 13 to the precipitation tank 8, where solid-liquid separation is performed in the precipitation tank 8, and the separated liquid is discharged appropriately. Further, the sludge that is separated and precipitated is supplied to the concentrator 9 and supplied to the solubilization tank 2. In this case, the aeration tank 13 has BOD removal and nitrification functions. A part of the nitrification liquid, which is the treatment liquid in the aeration tank 13, is returned to the pre-anoxic tank 11, preferably (not shown).
[0051]
Further, the sludge solubilized in the solubilization tank 2 is returned to the compatible tank 12 and circulates in the compatible tank 12, the oxygen-free tank 6, the aeration tank 13, the precipitation tank 8, the concentrator 9, and the solubilization tank 2. It will be. The sludge separated in the sedimentation tank 8 is returned to the pre-anoxic tank 11 as well as being supplied to the concentrator 9. In addition, sludge is returned to the anaerobic tank 11 from the anaerobic tank 4 and the compatible tank 12.
[0052]
The HRT of the solubilization tank 2 is preferably set to 12 to 72 hours as in the third embodiment, more preferably set to 24 to 72 hours, and most preferably set to 36 to 48 hours.
HRT of tanks other than the solubilization tank 2 is 0.5 to 1.5 hours in the anaerobic tank 11, 0.5 to 2 hours in the anaerobic tank 4, 0.5 to 1 hour in the compatible tank 12, and oxygen-free It is preferable to set it as 1 to 3 hours in the tank 6, 3 to 6 hours in the aeration tank 13, 0.5 to 1 hour in the anaerobic tank 11, 0.5 to 1 hour in the anaerobic tank 4, and in the compatible tank 12 0.5 to 1 hour, 1 to 2 hours in the anaerobic tank 6, and 3.5 to 5 hours in the aeration tank 13 are more preferable.
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially the various Bacillus disclosed in Embodiment 1( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set so as to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
In addition, although the concentration apparatus 9 was provided in the processing apparatus of this embodiment, providing the concentration machine 9 is not an essential condition for the present invention.
[0053]
(Embodiment 7)
In this embodiment, as shown in FIG. 8, a nitrification tank 10 is provided on the rear stage side of the solubilization tank 2, and this is different from the sixth embodiment.
That is, in this embodiment, the sludge solubilized in the solubilization tank 2 is supplied to the nitrification tank 10, and the ammonia in the sludge is converted into nitrous acid or nitric acid in the nitrification tank 10, and then returned to the compatible tank 12. Will be. The sludge separated in the settling tank 8 is supplied to the concentrator 9 and returned to the pre-anoxic tank 11 as in the sixth embodiment, and is also directly supplied to the nitrification tank 10 in this embodiment.
Since other configurations and processing procedures are the same as those in the sixth embodiment, description thereof is omitted.
Note that the HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably set to 18 to 48 hours, and most preferably set to 20 to 36 hours, as in the fifth embodiment. .
Further, as a microorganism for producing a solubilizing enzyme for solubilizing sludge, thermophilic bacteria, in particular, various Bacillus disclosed in the first embodiment.( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Furthermore, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment. When an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set so as to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0054]
(Embodiment 8)
As shown in FIG. 9, the processing apparatus of this embodiment includes a dissolved oxygen reduction tank 16, an anaerobic tank 4, an oxygen-free tank 6, an aeration tank 13, a precipitation tank 8, a concentrator 9, and a solubilization tank 2. ing. In this embodiment, in addition to supplying treated water that has been anaerobically treated in the anaerobic tank 2 to the anoxic tank 4, treated water that has been treated so as to reduce dissolved oxygen in the dissolved oxygen reducing tank 16 is also added to the anoxic tank 6. To supply.
[0055]
The treated water supplied to the anaerobic tank 6 and denitrified is further supplied to the aeration tank 13 and treated aerobically by aeration and stirring, and further supplied to the precipitation tank 8 for solid-liquid separation. The separated liquid is appropriately discharged or the like, and the sludge that is the separated solid is supplied to the concentrator 9 and part of the sludge is returned to the aeration tank 13.
Further, the nitrification liquid is denitrified by returning a part of the treatment liquid in the aeration tank 13, that is, a part of the nitrification liquid, to the anoxic tank 6 through the dissolved oxygen reduction tank 16. The denitrification efficiency can be stabilized by charging the nitrification liquid into an oxygen-free tank and reducing the dissolved oxygen in the nitrification liquid.
Further, the sludge concentrated by the concentrator 9 is supplied to the solubilization tank 2 and solubilized, and then returned to the dissolved oxygen reduction tank 16.
The sludge supplied to the anaerobic tank 6 is also returned to the anaerobic tank 4 and further returned from the anaerobic tank 4 to the dissolved oxygen reduction tank 16.
[0056]
The HRT of the solubilization tank 2 is preferably set to 12 to 72 hours as in the third embodiment, more preferably set to 24 to 72 hours, and most preferably set to 36 to 48 hours.
HRT of tanks other than the solubilization tank 2 is 0.15-0.3 hours in the dissolved oxygen reduction tank 16, 0.5-2 hours in the anaerobic tank 4, 1-3 hours in the anaerobic tank 6, and the aeration tank 13 3 to 6 hours, preferably 0.17 to 0.25 hours in the dissolved oxygen reduction tank 16, 1 to 1.5 hours in the anaerobic tank 4, 1-2 hours in the anaerobic tank 6, and the aeration tank 13 And more preferably 3.5 to 5 hours.
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially the various Bacillus disclosed in Embodiment 1( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0057]
(Embodiment 9)
In the present embodiment, as shown in FIG. 10, a nitrification tank 10 is provided on the rear stage side of the solubilization tank 2, which is different from the above-described eighth embodiment.
That is, in this embodiment, the sludge solubilized in the solubilization tank 2 is supplied to the nitrification tank 10, and the ammonia in the sludge is converted into nitrous acid or nitric acid in the nitrification tank 10, and then the dissolved oxygen reduction tank 16 is used. Will be returned to. Further, a part of the sludge in the sedimentation tank 8 is supplied to the nitrification tank 10 so that the nitrification treatment is maintained.
Since other configurations and processing procedures are the same as those in the eighth embodiment, description thereof is omitted.
Note that the HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably set to 18 to 48 hours, and most preferably set to 20 to 36 hours, as in the fifth embodiment. .
Further, as a microorganism for producing a solubilizing enzyme for solubilizing sludge, thermophilic bacteria, in particular, various Bacillus disclosed in the first embodiment.( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Furthermore, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment. When an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set so as to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0058]
(Embodiment 10)
As shown in FIG. 11, the organic wastewater treatment apparatus of the present embodiment includes an anaerobic tank 4, an oxygen-free tank 6, an aeration tank 13, a precipitation tank 8, and a solubilization tank 2.
In this embodiment, after anaerobic treatment of raw water is performed in the anaerobic tank 4 and the phosphorus component in the sludge is released, it is supplied to the oxygen-free tank 6 and denitrified in the oxygen-free tank 6. The treatment liquid denitrified in the anaerobic tank 6 is supplied to the aeration tank 13, and the ammonia contained in the sludge changes to nitrous acid and nitric acid in the aeration tank 13. That is, the aeration tank 13 is nitrified.
[0059]
Next, the treatment liquid that has been nitrified in the aeration tank 13 is supplied to the precipitation tank 8. In this settling tank 8, solid-liquid separation is performed, and the separated liquid is discharged or the like, and a part of the sludge that is separated and precipitated is supplied to the solubilization tank 2, and the rest is returned sludge. And returned to the anaerobic tank 4.
The sludge after the solubilization treatment is returned to the oxygen-free tank 6, denitrification treatment in the oxygen-free tank 6, treatment in the aeration tank 13, solid-liquid separation in the precipitation tank 8, and solubilization treatment in the solubilization tank 2. Will be repeated in a cycle. Further, a part of the nitrification liquid treated in the aeration tank 13 is returned to the anoxic tank 6 or the anaerobic tank 4 and denitrified in the anoxic tank 6.
The HRT of the solubilization tank 2 is preferably set to 12 to 72 hours as in the third embodiment, more preferably set to 24 to 72 hours, and most preferably set to 36 to 48 hours.
HRT of tanks other than the solubilization tank 2 is 0.15-0.3 hours in the dissolved oxygen reduction tank 16, 0.5-2 hours in the anaerobic tank 4, 1-3 hours in the anaerobic tank 6, and an aerobic tank 17 is preferably 3 to 6 hours, 0.17 to 0.25 hours in the dissolved oxygen reduction tank 16, 1 to 1.5 hours in the anaerobic tank 4, and 1-2 hours in the anaerobic tank 6. More preferably, the time in the tank 17 is 3.5 to 5 hours.
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially the various Bacillus disclosed in Embodiment 1( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0060]
(Embodiment 11)
In this embodiment, as shown in FIG. 12, the sludge solubilized in the solubilization tank 2 is returned to the anaerobic tank 4, and this is different from the case of the embodiment 10 in which the sludge is returned to the anaerobic tank 6. .
Embodiments of anaerobic treatment in the anaerobic tank 4, denitrification treatment in the anaerobic tank 6, nitrification treatment in the aeration tank 13, solid-liquid separation in the precipitation tank 8, and solubilization treatment in the solubilization tank 2 10 and the description thereof is omitted. Also in this embodiment, a part of the nitrifying solution is returned to the anoxic tank 6 or the anaerobic tank 4.
The HRT of the solubilization tank 2 is preferably set to 12 to 72 hours as in the third embodiment, more preferably set to 24 to 72 hours, and most preferably set to 36 to 48 hours.
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially the various Bacillus disclosed in Embodiment 1( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0061]
Embodiment 12
In the present embodiment, a nitrification tank 10 is provided at the subsequent stage of the solubilization tank 2 as shown in FIG. In the present embodiment, the sludge treated in the solubilization tank 2 is supplied to the nitrification tank 10, and ammonia in the sludge is converted into nitrous acid or nitric acid in the nitrification tank 10 and then returned to the anoxic tank 6. become. Further, sludge is supplied from the sedimentation tank 8 to the nitrification tank 10.
Embodiments of anaerobic treatment in the anaerobic tank 4, denitrification treatment in the anaerobic tank 6, nitrification treatment in the aeration tank 13, solid-liquid separation in the precipitation tank 8, and solubilization treatment in the solubilization tank 2 11 and the description thereof is omitted.
However, the HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably 18 to 48 hours, and most preferably 20 to 36 hours, as in the fifth embodiment. .
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially the various Bacillus disclosed in Embodiment 1( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0062]
(Embodiment 13)
Also in the present embodiment, the nitrification tank 10 is provided in the subsequent stage of the solubilization tank 2 as in the twelfth embodiment, but the sludge after the treatment in the nitrification tank 10 is transferred to the anaerobic tank 4 as shown in FIG. This is different from the case of the twelfth embodiment which is returned to the oxygen-free tank 6 in this respect.
Embodiments of anaerobic treatment in the anaerobic tank 2, denitrification treatment in the anaerobic tank 6, nitrification treatment in the aeration tank 13, solid-liquid separation in the precipitation tank 8, and solubilization treatment in the solubilization tank 2 are the embodiments. 10 and the description thereof is omitted.
The HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably set to 18 to 48 hours, and most preferably set to 20 to 36 hours, as in the fifth embodiment.
[0063]
Also in the present embodiment, as in the twelfth embodiment, it is necessary to supply sludge from the sedimentation tank 8 to the nitrification tank 10.
In addition, as microorganisms which produce the solubilizing enzyme for solubilizing sludge, thermophilic bacteria, especially the various Bacillus disclosed in Embodiment 1( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0064]
(Embodiment 14)
As shown in FIG. 15, the organic wastewater treatment apparatus of the present embodiment includes a reaction tank 1, a solubilization tank 2, and a storage tank 3. In the reaction tank 1, the organic wastewater is treated batchwise as in the first embodiment.
[0065]
In this embodiment, as shown in FIG. 16, the anaerobic process by stirring and the aerobic process by aeration are repeated three times, and then the precipitation, solid-liquid separation, and solubilization processes by stopping aeration are performed. Will be made in circulation. The anaerobic treatment and aerobic treatment repetition steps, precipitation and solid-liquid separation steps are performed in the reaction tank 1, and the solubilization treatment process is performed in the solubilization tank 2.
It is possible to adjust the processing time of each process so that the batch processing of the wastewater treatment from the inflow acceptance of the raw water to the discharge of the treated water is performed a plurality of times (for example, 2 to 4 times) per day. Depending on the properties, amount, etc., the processing time of each step may be adjusted so that batch processing is performed about once a day or about twice every three days.
The wastewater treatment process time is, for example, inflow 60 minutes, anaerobic 60 minutes, aerobic 70 minutes, anaerobic 30 minutes, aerobic 80 minutes, anaerobic 20 minutes, aerobic 10 minutes, precipitation 40 minutes, and discharge 40 minutes. Yes.
[0066]
In the present embodiment, nitrification is performed in the aerobic treatment step, and denitrification treatment is performed in the anaerobic treatment step.
The solubilized solution after the solubilization treatment is returned to the reaction tank 2 in the first (first) aerobic treatment step. The timing of the return is determined in relation to the processing time of the first aerobic processing step, but is 3 hours to 30 minutes before aeration stop, preferably 1 hour to 30 minutes before.
[0067]
In this embodiment, since the storage tank 3 is provided after the solubilization tank 2, the first aerobic treatment is performed by temporarily storing the solubilized liquid processed in the solubilization tank 2 in the storage tank 3. This is preferable because the timing, amount and the like of returning the solubilized liquid to the reaction tank 2 in the process can be easily adjusted.
The HRT of the solubilization tank 2 is preferably 12 to 72 hours, more preferably 18 to 48 hours, and most preferably 20 to 36 hours, as in the first embodiment.
Examples of microorganisms that produce solubilizing enzymes for solubilizing sludge include thermophilic bacteria, especiallyProcessingVarious Bacillus disclosed in aspect 1( Bacillus )Genus bacteria and Geobacillus(GeobacillusIt is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0068]
(Embodiment 15)
As shown in FIG. 17, the organic wastewater treatment apparatus of the present embodiment is provided with a storage tank 3 at the rear stage of the reaction tank 1 and further with a solubilization tank 2 at the subsequent stage. In the present embodiment, sludge after nitrification and denitrification treatment is temporarily stored in the storage tank 3, and a necessary amount of sludge to be solubilized is supplied to the solubilization tank 2.
[0069]
By supplying only the necessary amount of sludge to be solubilized to the solubilization tank 2, the amount of the solubilized liquid to be returned to the aerobic treatment step can be adjusted in advance. .
The points of anaerobic treatment and aerobic treatment are repeated, and thereafter precipitation and solid-liquid separation are performed, as in the case of the fourteenth embodiment.
The HRT of the solubilization tank 2 is preferably 12 to 72 hours, more preferably 18 to 48 hours, and most preferably 20 to 36 hours, as in the first embodiment.
Examples of microorganisms that produce a solubilizing enzyme for solubilizing sludge are thermophilic bacteria, particularly the various Bacillus disclosed in Embodiment 1.( Bacillus )Genus bacteria and Geobacillus(Geobacillus)It is preferred to use a genus bacterium.
Further, the temperature during the solubilization treatment is desirably a temperature range of 50 to 90 ° C. as in the first embodiment, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, a temperature range of 55 to 70 ° C. It is preferable to set to, and a range of 60 to 65 ° C. is particularly preferable. Further, the pH during the solubilization treatment is set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.
[0070]
(Embodiment 16)
This embodiment is an embodiment provided with means for removing phosphorus when the sludge generated by biological treatment such as nitrification and denitrification contains phosphorus.
In this embodiment, a flocculant such as polyaluminum chloride is added on the rear stage side of the precipitation tank 8 as in each of the above embodiments, and phosphorus in the treated water is removed by coagulation precipitation, or a filter medium is provided to perform coagulation filtration. Removes phosphorus.
[0071]
In each of the embodiments described above, in an embodiment including an anaerobic treatment step and an aerobic treatment step (aeration treatment step), if phosphorus is contained in the treated water or sludge, the phosphorus is contained in the sludge in the anaerobic treatment step. Released from microorganisms and taken up by microorganisms in the aerobic process. However, even if phosphorus is released and taken up in this way, if a sludge solubilization treatment is incorporated, the treatment liquid containing phosphorus may be discharged out of the system, and the anaerobic treatment step and the aerobic treatment step. The function of releasing and taking up phosphorus cannot be achieved by both.
[0072]
Therefore, the phosphorus contained in the treated water and sludge can be positively removed by providing the phosphorus removal means as described above. This is applicable to both continuous processing and batch processing.
[0073]
(Embodiment 17)
In this embodiment, instead of the means using the flocculant or the like as the phosphorus removal means, a phosphorus release tank provided with phosphorus separation means is provided on the rear stage side of the precipitation tank 8, and the sludge separated in the precipitation tank 8 is removed. In the phosphorus release tank, the phosphorus is released by exposing the phosphorus from the sludge in anaerobic condition, heated condition, etc., and the released phosphorus is separated into the phosphorus release sludge and the phosphorus eluate and aggregated in the phosphorus release liquid It can be removed by adding an agent or the like. The phosphorus release sludge is solubilized.
[0074]
Therefore, also in this embodiment, various tanks as in the above embodiments can be provided on the upstream side of the precipitation tank 8. This is applicable to both continuous and batch processing.
[0075]
(Embodiment 18)
In this embodiment, iron plate, iron particles, steel wool, etc. are charged into the reaction tank 1, the aeration tank 13, the nitrification tank 10, the solubilization tank 2, the anoxic tank 6, etc. of the above-described embodiments, and the phosphorus component Is an embodiment in which phosphorus is removed by attaching to the iron.
[0076]
In the present embodiment, an existing reaction tank 1 in the processing apparatus is used without using a flocculant as in the above-described Embodiment 16 and without separately providing a phosphorus release tank for releasing phosphorus as in the above-described Embodiment 17. By simply putting the iron material into the aeration tank 13, the solubilization tank 2, the anoxic tank 6, etc., phosphorus can be easily removed by attaching a phosphorus component to the iron material.
[0077]
(Other embodiments)
In Embodiments 3, 4, 5 and the like, the acid fermented liquor obtained by gas-decomposing and fermenting the residual rice discharged from the food factory was used as the liquid to be treated. However, the kind of the treatment is limited to this. It doesn't matter what kind of thing it is.
[0078]
In addition, as in the third, fourth, and fifth embodiments, the provision of the fermentation liquid storage tank 3 is not an essential condition for the present invention. For example, as shown in FIG. 18, there is no fermentation liquid storage tank 3 and an anaerobic tank. 4. It is also possible to use a processing apparatus including the primary aeration tank 5, the oxygen-free tank 6, the secondary aeration tank 7, the precipitation tank 8, and the solubilization tank 2. For example, when only the sewage from the sewage treatment plant is treated, the treatment apparatus shown in FIG. 18 can be preferably used.
[0079]
Furthermore, exhaust gas may be discharged from the solubilization tank 2, but by introducing such exhaust gas into the nitrification tank or the aeration tank of the above embodiment, the odor of the exhaust gas can be removed and the high temperature It is preferable to introduce exhaust gas into a nitrification tank or an aeration tank, because the temperature of each tank can be made higher than that of aeration with ordinary air, thereby increasing the activity of microorganisms and, as a result, improving the processing efficiency.
[0080]
Furthermore, the kind of organic waste water which should be processed does not ask | require.
[0081]
【The invention's effect】
As described above, the present invention reduces the amount of sludge generated by nitrification and denitrification in order to solubilize sludge generated by nitrification and denitrification after nitrification and denitrification of organic wastewater. In addition, there is an effect that the nitrogen-containing organic component and the nitrogen-containing inorganic component in the treated water released to the outside of the treatment system can be greatly reduced as compared with the conventional case.
[0082]
Further, nitrification and denitrification treatment of organic wastewater is performed in a batch system including a nitrification step by aeration, and preferably 3 hours to 30 minutes before stopping the aeration, preferably 1 hour to 30 minutes before stopping aeration. When the solubilization treatment liquid is returned to the reaction tank, the organic matter contained in the solubilization treatment sludge can be effectively used as a proton source (BOD source) in the denitrification treatment, thereby promoting denitrification. Therefore, since the amount of chemicals such as methanol generally used as a proton source can be reduced, there is an effect that the cost associated with the amount of chemicals can be reduced.
[0083]
Furthermore, when organic wastewater nitrification and denitrification treatment includes anaerobic treatment steps such as anaerobic treatment steps and aeration treatments, phosphorus components are contained in sludge generated by nitrification and denitrification treatments. Even in this case, phosphorus is released by anaerobic treatment, phosphorus is taken up by aerobic treatment, and by providing a phosphorus removing means, it is possible to suitably prevent the phosphorus component from being discharged out of the system.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing an organic wastewater treatment apparatus as one embodiment.
FIG. 2 is a block diagram of a batch processing process performed by the processing apparatus of FIG.
FIG. 3 is a block diagram of another example batch processing step performed by the processing apparatus of FIG. 1;
FIG. 4 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 5 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 6 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 7 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 8 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 9 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 10 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 11 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 12 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 13 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 14 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 15 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
16 is a block diagram of batch processing steps performed by the processing apparatus of FIG.
FIG. 17 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
FIG. 18 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment.
[Explanation of symbols]
1 ... Reaction tank
2 ... Solubilization tank
4 ... Anaerobic tank
5 ... Primary aeration tank
6 ... Anoxic tank
7 ... Secondary aeration tank
10 ... Nitrification tank
13 ... Aeration tank

Claims (21)

A method for biologically treating organic wastewater, characterized by nitrifying and denitrifying the organic wastewater and then solubilizing sludge generated by the nitrification and denitrification treatment Method. The method for treating organic wastewater according to claim 1, wherein the nitrification and denitrification treatment of the organic wastewater is carried out batchwise in the reaction tank 1. The method for treating organic wastewater according to claim 2, wherein the nitrification treatment is performed by aeration, and the denitrification treatment is performed by stopping the aeration. The method for treating organic wastewater according to claim 2 or 3, wherein the solubilized solution is returned to the reaction tank 1 3 hours to 30 minutes before aeration is stopped. The method for treating organic wastewater according to claim 2 or 3, wherein the solubilized treatment liquid is returned to the reaction tank 1 1 hour to 30 minutes before aeration is stopped. The method for treating organic wastewater according to claim 1, wherein the nitrification and denitrification treatment of the organic wastewater is performed by an anaerobic treatment step, a primary aeration step, a denitrification step in an oxygen-free tank, and a secondary aeration step. The nitrification and denitrification treatment of organic wastewater is performed by a denitrification step in an oxygen-free tank, an anaerobic treatment step, a treatment step in a compatible tank, a denitrification step in an oxygen-free tank, and an aeration process. Organic wastewater treatment method. The method for treating organic wastewater according to claim 6 or 7, wherein nitrification is performed after the solubilization treatment. The organic waste water according to claim 1, wherein the nitrification and denitrification treatment of the organic wastewater is performed by an anaerobic treatment step, a denitrification step in an oxygen-free tank, and an aeration step, and the dissolved oxygen in the treatment solution after the solubilization treatment is reduced. Of waste water. The method for treating organic wastewater according to claim 1, wherein the nitrification and denitrification treatment of the organic wastewater is performed by an anaerobic treatment step, a denitrification step in an oxygen-free tank, and an aeration step. The method for treating organic wastewater according to any one of claims 1 to 10, wherein the sludge is concentrated before the solubilization treatment. The method for treating organic wastewater according to any one of claims 1 to 11, wherein sludge is solubilized by an aerobic thermophilic bacterium. The method for treating organic wastewater according to claim 12, wherein the aerobic thermophilic bacterium is a microorganism belonging to the genus Bacillus . The method for treating organic wastewater according to any one of claims 1 to 13, comprising a step of removing phosphorus in sludge generated by nitrification and denitrification. An apparatus for biologically treating organic wastewater, comprising means for nitrifying and denitrifying organic wastewater, and a solubilization tank for solubilizing sludge generated by nitrification and denitrification Organic wastewater treatment equipment. The organic wastewater treatment apparatus according to claim 15, wherein the means for nitrifying and denitrifying the organic wastewater is a means for nitrifying and denitrifying in the batch type reaction tank 1. The treatment of organic wastewater according to claim 15, wherein the means for nitrifying and denitrifying the organic wastewater is a means for nitrifying and denitrifying with the anaerobic tank 4, the primary aeration tank 5, the anoxic tank 6, and the secondary aeration tank 7. apparatus. 16. The organic material according to claim 15, wherein the means for nitrifying and denitrifying the organic wastewater is a means for nitrifying and denitrifying the pre-anoxic tank 11, the anaerobic tank 4, the compatible tank 12, the anoxic tank 6, and the aeration tank 13. Waste water treatment equipment. The means for nitrifying and denitrifying organic wastewater is a means for nitrifying and denitrifying by the anaerobic tank 4, the oxygen-free tank 6, and the aeration tank 13, and reducing dissolved oxygen in the treated liquid after solubilization treatment The organic wastewater treatment apparatus according to claim 15, wherein a tank 16 is provided. The organic wastewater treatment apparatus according to claim 15, wherein the means for nitrifying and denitrifying the organic wastewater is a means for nitrifying and denitrifying with the anaerobic tank 4, the anoxic tank 6, and the aeration tank 13. The organic wastewater treatment apparatus according to any one of claims 15 to 20, further comprising means for removing phosphorus in sludge generated by nitrification and denitrification treatment.

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